Taurine-induced attenuation of MPP+ neurotoxicity in vitro: a possible role for the GABA(A) subclass of GABA receptors.

PubMed

O'Byrne, M B; Tipton, K F

2000-05-01

Taurine is a sulphur-containing beta-amino acid found in high (millimolar) concentrations in excitable tissues such as brain and heart. Its suggested roles include osmoregulator, thermoregulator, neuromodulator, and potential neurotransmitter. This amino acid has also been shown to be released in large concentrations during ischaemia and excitotoxin-induced neuronal damage. Here we report a protective effect of taurine against MPP(+)-induced neurotoxicity in coronal slices from rat brain. Significant protective effects were observed at taurine concentrations of 20 and 1 mM, suggesting a potential role for taurine in cases of neuronal insult. Studies with the synthetic taurine analogues taurine phosphonate, guanidinoethane sulphonate, and trimethyltaurine suggested the observed effect to be mediated via an extracellular mechanism. The use of GABA receptor ligands muscimol and bicuculline indicated the effect to be mediated through activation of GABA(A) receptors.

Mechanical properties of gray and white matter brain tissue by indentation

PubMed Central

Budday, Silvia; Nay, Richard; de Rooij, Rijk; Steinmann, Paul; Wyrobek, Thomas; Ovaert, Timothy C.; Kuhl, Ellen

2015-01-01

The mammalian brain is composed of an outer layer of gray matter, consisting of cell bodies, dendrites, and unmyelinated axons, and an inner core of white matter, consisting primarily of myelinated axons. Recent evidence suggests that microstructural differences between gray and white matter play an important role during neurodevelopment. While brain tissue as a whole is rheologically well characterized, the individual features of gray and white matter remain poorly understood. Here we quantify the mechanical properties of gray and white matter using a robust, reliable, and repeatable method, flat-punch indentation. To systematically characterize gray and white matter moduli for varying indenter diameters, loading rates, holding times, post-mortem times, and locations we performed a series of n=192 indentation tests. We found that indenting thick, intact coronal slices eliminates the common challenges associated with small specimens: it naturally minimizes boundary effects, dehydration, swelling, and structural degradation. When kept intact and hydrated, brain slices maintained their mechanical characteristics with standard deviations as low as 5% throughout the entire testing period of five days post mortem. White matter, with an average modulus of 1.895kPa±0.592kPa, was on average 39% stiffer than gray matter, p<0.01, with an average modulus of 1.389kPa±0.289kPa, and displayed larger regional variations. It was also more viscous than gray matter and responded less rapidly to mechanical loading. Understanding the rheological differences between gray and white matter may have direct implications on diagnosing and understanding the mechanical environment in neurodevelopment and neurological disorders. PMID:25819199

Novel Approach to Estimate Kidney and Cyst Volumes using Mid-Slice Magnetic Resonance Images in Polycystic Kidney Disease

PubMed Central

Bae, Kyongtae T; Tao, Cheng; Wang, Jinhong; Kaya, Diana; Wu, Zhiyuan; Bae, Junu T; Chapman, Arlene B; Torres, Vicente E; Grantham, Jared J; Mrug, Michal; Bennett, William M; Flessner, Michael F; Landsittel, Doug P

2013-01-01

Objective To evaluate whether kidney and cyst volumes can be accurately estimated based on limited area measurements from MR images of patients with autosomal dominant polycystic kidney disease (ADPKD). Materials and Methods MR coronal images of 178 ADPKD participants from the Consortium for Radiologic Imaging Studies of ADPKD (CRISP) were analyzed. For each MR image slice, we measured kidney and renal cyst areas using stereology and region-based thresholding methods, respectively. The kidney and cyst ‘observed’ volumes were calculated by summing up the area measurements of all the slices covering the kidney. To estimate the volume, we selected a coronal mid-slice in each kidney and multiplied its area by the total number of slices (‘PANK2’ for kidney and ‘PANC2’ for cyst). We then compared the kidney and cyst volumes predicted from PANK2 and PANC2, respectively, to the corresponding observed volumes, using a linear regression analysis. Results The kidney volume predicted from PANK2 correlated extremely well with the observed kidney volume: R2=0.994 for right and 0.991 for left kidney. The linear regression coefficient multiplier to PANK2 that best fit the kidney volume was 0.637 (95%CI: 0.629–0.644) for right and 0.624 (95%CI: 0.616–0.633) for left kidney. The correlation between the cyst volume predicted from PANC2 and the observed cyst volume was also very high: R2=0.984 for right and 0.967 for left kidney. The least squares linear regression coefficient for PANC2 was 0.637 (95%CI: 0.624–0.649) for right and 0.608 (95%CI: 0.591–0.625) for left kidney. Conclusion Kidney and cyst volumes can be closely approximated by multiplying the product of the mid-slice area measurement and the total number of slices in the coronal MR images of ADPKD kidneys by 0.61–0.64. This information will help save processing time needed to estimate total kidney and cyst volumes of ADPKD kidneys. PMID:24107679

Effect of long-term (2 years) exposure of mouse brains to global system for mobile communication (GSM) radiofrequency fields on astrocytic immunoreactivity.

PubMed

Court-Kowalski, Stefan; Finnie, John W; Manavis, Jim; Blumbergs, Peter C; Helps, Stephen C; Vink, Robert

2015-04-01

This study was designed to determine whether long-term (2 years) brain exposure to mobile telephone radiofrequency (RF) fields produces any astrocytic activation as these glia react to a wide range of neural perturbations by astrogliosis. Using a purpose-designed exposure system at 900 MHz, mice were given a single, far-field whole body exposure at a specific absorption rate of 4 W/kg on five successive days per week for 104 weeks. Control mice were sham-exposed or freely mobile in a cage to control any stress caused by immobilization in the exposure module. Brains were perfusion-fixed with 4% paraformaldehyde and three coronal levels immunostained for glial fibrillary acidic protein (GFAP). These brain slices were then examined by light microscopy and the amount of this immunomarker quantified using a color deconvolution method. There was no change in astrocytic GFAP immunostaining in brains after long-term exposure to mobile telephony microwaves compared to control (sham-exposed or freely moving caged mice). It was concluded that long-term (2 years) exposure of murine brains to mobile telephone RF fields did not produce any astrocytic reaction (astrogliosis) detectable by GFAP immunostaining. © 2015 Wiley Periodicals, Inc.

The Effect of Temperature on Photoluminescence Enhancement of Quantum Dots in Brain Slices.

PubMed

Zhao, Fei; Kim, Jongsung

2017-04-01

In this paper, we investigated the effect of temperature on photoluminescence of quantum dots immobilized on the surface of an optical fiber in a rat brain slice. The optical fiber was silanized with 3-aminopropyl trimethoxysilane (APTMS), following which quantum dots with carboxyl functional group were immobilized on the optical fiber via amide bond formation. The effect of temperature on the fluorescence intensity of the quantum dots in rat brain slices was studied. This report shows that the fluorescence intensity of quantum dots increases with the increase of temperature of the brain slice. The fluorescence enhancement phenomenon appears to take place via electron transfer related to pH increase. With the gradual increase of temperature, the fluorescence intensity of quantum dots in solution decreased, while that in the brain slice increased. This enhanced thermal performance of QDs in brain slice makes suggestion for the study of QDs-based brain temperature sensors.

Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method.

PubMed

Ting, Jonathan T; Lee, Brian R; Chong, Peter; Soler-Llavina, Gilberto; Cobbs, Charles; Koch, Christof; Zeng, Hongkui; Lein, Ed

2018-02-26

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation.

Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method

PubMed Central

Chong, Peter; Soler-Llavina, Gilberto; Cobbs, Charles; Koch, Christof; Zeng, Hongkui; Lein, Ed

2018-01-01

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation. PMID:29553547

Free-floating adult human brain-derived slice cultures as a model to study the neuronal impact of Alzheimer's disease-associated Aβ oligomers.

PubMed

Mendes, Niele D; Fernandes, Artur; Almeida, Glaucia M; Santos, Luis E; Selles, Maria Clara; Lyra-Silva, Natalia; Machado, Carla M; Horta-Júnior, José A C; Louzada, Paulo R; De Felice, Fernanda G; Alvez-Leon, Soniza; Marcondes, Jorge; Assirati, João Alberto; Matias, Caio M; Klein, William L; Garcia-Cairasco, Norberto; Ferreira, Sergio T; Neder, Luciano; Sebollela, Adriano

2018-05-31

Slice cultures have been prepared from several organs. With respect to the brain, advantages of slice cultures over dissociated cell cultures include maintenance of the cytoarchitecture and neuronal connectivity. Slice cultures from adult human brain have been reported and constitute a promising method to study neurological diseases. Despite this potential, few studies have characterized in detail cell survival and function along time in short-term, free-floating cultures. We used tissue from adult human brain cortex from patients undergoing temporal lobectomy to prepare 200 μm-thick slices. Along the period in culture, we evaluated neuronal survival, histological modifications, and neurotransmitter release. The toxicity of Alzheimer's-associated Aβ oligomers (AβOs) to cultured slices was also analyzed. Neurons in human brain slices remain viable and neurochemically active for at least four days in vitro, which allowed detection of binding of AβOs. We further found that slices exposed to AβOs presented elevated levels of hyperphosphorylated Tau, a hallmark of Alzheimer's disease. Although slice cultures from adult human brain have been previously prepared, this is the first report to analyze cell viability and neuronal activity in short-term free-floating cultures as a function of days in vitro. Once surgical tissue is available, the current protocol is easy to perform and produces functional slices from adult human brain. These slice cultures may represent a preferred model for translational studies of neurodegenerative disorders when long term culturing in not required, as in investigations on AβO neurotoxicity. Copyright © 2018 Elsevier B.V. All rights reserved.

The challenge of localizing the anterior temporal face area: a possible solution.

PubMed

Axelrod, Vadim; Yovel, Galit

2013-11-01

Humans recognize faces exceptionally well. However, the neural correlates of face recognition are still elusive. Accumulated evidence in recent years suggests that the anterior temporal lobe (ATL), in particular face-selective region in the ATL, is a probable locus of face recognition. Unfortunately, functional MRI (fMRI) studies encounter severe signal drop-out in the ventral ATL, where that ATL face area resides. Consequently, all previous studies localized this region in no more than half of the subjects and its volume was relatively small. Thus, a systematic exploration of the properties of the ATL face area is scarce. In the current high-resolution fMRI study we used coronal slice orientation, which permitted us to localize the ATL face area in all the subjects. Furthermore, the volume of the area was much larger than was reported in previous studies. Direct within subjects comparison with data collected with the commonly used axial slice orientation confirmed that the advantage of the coronal slice orientation in revealing a reliable and larger face-selective area in the ATL. Finally, by displaying the face-selective activations resultant from coronal and axial scanning together, we demonstrate an organization principle of a chain of face-selective regions along the posterior-anterior axis in the ventral temporal lobe that is highly reproducible across all subjects. By using the procedure proposed here, a significant progress can be made in studying the neural correlates of face recognition. Copyright © 2013 Elsevier Inc. All rights reserved.

In Situ Activation of Antigen-Specific CD8+ T Cells in the Presence of Antigen in Organotypic Brain Slices1

PubMed Central

Ling, Changying; Verbny, Yakov I.; Banks, Matthew I.; Sandor, Matyas; Fabry, Zsuzsanna

2012-01-01

The activation of Ag-specific T cells locally in the CNS could potentially contribute to the development of immune-mediated brain diseases. We addressed whether Ag-specific T cells could be stimulated in the CNS in the absence of peripheral lymphoid tissues by analyzing Ag-specific T cell responses in organotypic brain slice cultures. Organotypic brain slice cultures were established 1 h after intracerebral OVA Ag microinjection. We showed that when OVA-specific CD8+ T cells were added to Ag-containing brain slices, these cells became activated and migrated into the brain to the sites of their specific Ags. This activation of OVA-specific T cells was abrogated by the deletion of CD11c+ cells from the brain slices of the donor mice. These data suggest that brain-resident CD11c+ cells stimulate Ag-specific naive CD8+ T cells locally in the CNS and may contribute to immune responses in the brain. PMID:18523307

Diagnosis of the "large medial meniscus" of the knee on MR imaging.

PubMed

Samoto, Nobuhiko; Kozuma, Masakazu; Tokuhisa, Toshio; Kobayashi, Kunio

2006-11-01

Although several quantitative magnetic resonance (MR) diagnostic criteria for discoid lateral meniscus (DLM) have been described, there are no criteria by which to estimate the size of the medial meniscus. We define a medial meniscus that exceeds the normal size as a "large medial meniscus" (LMM), and the purpose of this study is to establish the quantitative MR diagnostic criteria for LMM. The MR imaging findings of 96 knees with arthroscopically confirmed intact semilunar lateral meniscus (SLM), 18 knees with intact DLM, 105 knees with intact semilunar medial meniscus (SMM) and 4 knees with torn LMM were analyzed. The following three quantitative parameters were measured: (a) meniscal width (MW): the minimum MW on the coronal slice; (b) ratio of the meniscus to the tibia (RMT): the ratio of minimum MW to maximum tibial width on the coronal slice; (c) continuity of the anterior and posterior horns (CAPH): the number of consecutive 5-mm-thick sagittal slices showing continuity between the anterior horn and the posterior horn of the meniscus on sagittal slices. Using logistic discriminant analysis between intact SLM and DLM groups and using descriptive statistics of intact SLM and SMM groups, the cutoff values used to discriminate LMM from SMM were calculated by MW and RMT. Moreover, the efficacy of these cutoff values and three slices of the cutoff values for CAPH were estimated in the medial meniscus group. "MW> or =11 mm" and "RMT> or =15%" were determined to be effective diagnostic criteria for LMM, while three of four cases in the torn LMM group were true positives and specificity was 99% in both criteria. When "CAPH> or =3 slices" was used as a criterion, three of four torn LMM cases were true positives and specificity was 93%.

Geometry Processing of Conventionally Produced Mouse Brain Slice Images.

PubMed

Agarwal, Nitin; Xu, Xiangmin; Gopi, M

2018-04-21

Brain mapping research in most neuroanatomical laboratories relies on conventional processing techniques, which often introduce histological artifacts such as tissue tears and tissue loss. In this paper we present techniques and algorithms for automatic registration and 3D reconstruction of conventionally produced mouse brain slices in a standardized atlas space. This is achieved first by constructing a virtual 3D mouse brain model from annotated slices of Allen Reference Atlas (ARA). Virtual re-slicing of the reconstructed model generates ARA-based slice images corresponding to the microscopic images of histological brain sections. These image pairs are aligned using a geometric approach through contour images. Histological artifacts in the microscopic images are detected and removed using Constrained Delaunay Triangulation before performing global alignment. Finally, non-linear registration is performed by solving Laplace's equation with Dirichlet boundary conditions. Our methods provide significant improvements over previously reported registration techniques for the tested slices in 3D space, especially on slices with significant histological artifacts. Further, as one of the application we count the number of neurons in various anatomical regions using a dataset of 51 microscopic slices from a single mouse brain. To the best of our knowledge the presented work is the first that automatically registers both clean as well as highly damaged high-resolutions histological slices of mouse brain to a 3D annotated reference atlas space. This work represents a significant contribution to this subfield of neuroscience as it provides tools to neuroanatomist for analyzing and processing histological data. Copyright © 2018 Elsevier B.V. All rights reserved.

A Proposal of New Reference System for the Standard Axial, Sagittal, Coronal Planes of Brain Based on the Serially-Sectioned Images

PubMed Central

Park, Jin Seo; Park, Hyo Seok; Shin, Dong Sun; Har, Dong-Hwan; Cho, Zang-Hee; Kim, Young-Bo; Han, Jae-Yong; Chi, Je-Geun

2010-01-01

Sectional anatomy of human brain is useful to examine the diseased brain as well as normal brain. However, intracerebral reference points for the axial, sagittal, and coronal planes of brain have not been standardized in anatomical sections or radiological images. We made 2,343 serially-sectioned images of a cadaver head with 0.1 mm intervals, 0.1 mm pixel size, and 48 bit color and obtained axial, sagittal, and coronal images based on the proposed reference system. This reference system consists of one principal reference point and two ancillary reference points. The two ancillary reference points are the anterior commissure and the posterior commissure. And the principal reference point is the midpoint of two ancillary reference points. It resides in the center of whole brain. From the principal reference point, Cartesian coordinate of x, y, z could be made to be the standard axial, sagittal, and coronal planes. PMID:20052359

Novel active contour model based on multi-variate local Gaussian distribution for local segmentation of MR brain images

NASA Astrophysics Data System (ADS)

Zheng, Qiang; Li, Honglun; Fan, Baode; Wu, Shuanhu; Xu, Jindong

2017-12-01

Active contour model (ACM) has been one of the most widely utilized methods in magnetic resonance (MR) brain image segmentation because of its ability of capturing topology changes. However, most of the existing ACMs only consider single-slice information in MR brain image data, i.e., the information used in ACMs based segmentation method is extracted only from one slice of MR brain image, which cannot take full advantage of the adjacent slice images' information, and cannot satisfy the local segmentation of MR brain images. In this paper, a novel ACM is proposed to solve the problem discussed above, which is based on multi-variate local Gaussian distribution and combines the adjacent slice images' information in MR brain image data to satisfy segmentation. The segmentation is finally achieved through maximizing the likelihood estimation. Experiments demonstrate the advantages of the proposed ACM over the single-slice ACM in local segmentation of MR brain image series.

[Drainage characteristic of the brain interstitial fluid detected by using fluorescence and magnetic tracer method].

PubMed

Zhao, Y; Li, Y Q; Li, H Y; Li, Y L; Liu, L X; Yuan, L; Zhang, S J; Han, H B

2017-04-18

Compare the results of molecular diffusion and mass flow in the interstitial space(ISS) displayed by using optical and magnetic probes and study partitioned drainage of the brain interstitial fluid (ISF). In the study, 36 male SD rats were randomly divided into fluorescent inspection group (18), magnetic tracer group (18). Then they were divided equally into caudate nucleus (Cn), thalamus (T) and substantia nigra (Sn) subgroup, 6 rats in each subgroup. Referencing the brain stereotaxic atlas, the coronal globus pallidus as center level, Cn, T or Sn were acted as puncture positioning target. A 10 μL microsyringe was stereotaxically positioned and the lucifer yellow (LY) solution of 2 μL 10 mmol/L was infused into centric position. The coronary slices undergo cardiac perfusion and fix respectively in time point Cn 3 h, T 2 h and Sn 1 h. The rat brain was placed in rat stainless steel brain matrices and cut backward along visual intersection. The injection point of coronal slice as the center level, take 3 slices in front of the center level and 2 slices behind of it. 1 mm for each slice and 6 slices in total. Then slices were detected by laser scanning confocal microscope (LSCM). Simultaneous, in the same coordinate brain regions of another three groups, a gadolinium-diethylene triamine pentaacetic acidm (Gd-DTPA) solution of 2 μL 10 mmol/L was infused into different injection and detected by MRI tracer-based method. Then the Radiant can be used to measure distribution area of Gd-DTPA. LY and Gd-DTPA have different distribution regions in Cn, T and Sn. After LY and Gd-DTPA were introduced into the Cn subgroup 3 h, compare the 1 to 6 levels distribution area of LY and Gd-DTPA as follows: (10.95±4.27) mm 2 vs. (8.33±2.25) mm 2 , (18.16±4.74) mm 2 vs. (16.42±2.88) mm 2 , (24.57±3.65) mm 2 vs. (20.75±2.29) mm 2 , (34.81±3.32) mm 2 vs. (28.88±1.51) mm 2 , (30.53±3.12) mm 2 vs. (20.92±2.75) mm 2 , (12.15±4.92) mm 2 vs. (10.00±1.89) mm 2 . The statistical analysis of every level was made by T test, and the difference of the distribution area between the two tracers were not statistically significant (t=0.940, P=0.400; t=0.546, P=0.614; t=1.534, P=0.200; t=2.809, P=0.480; t=2.693, P=0.055; t=0.707, P=0.518); After LY and Gd-DTPA were introduced into the T subgroup 2 h, compare the 1-6 levels distribution area of LY and Gd-DTPA as follows: (5.56±4.61) mm 2 vs. (3.33±2.25) mm 2 , (16.21±3.36) mm 2 vs. (11.42±2.88) mm 2 , (19.00±5.21) mm 2 vs. (15.75±2.29) mm 2 , (25.32±5.49) mm 2 vs. (22.33±3.25) mm 2 , (17.34±5.31) mm 2 vs. (15.92±2.75) mm 2 , (7.67±6.19) mm 2 vs. (5.00±1.89) mm 2 . The statistical analysis of every level was made by T test, and the difference of the distribution area between the two tracers were not statistically significant (t=0.753, P=0.493; t=1.875, P=0.134; t=0.990, P=0.378; t=0.810, P=0.464; t=0.413, P=0.701; t=0.716, P=0.514); After LY and Gd-DTPA were introduced into the Sn subgroup 1 h, compare the 1-6 levels distribution area of LY and Gd-DTPA as follows: (6.78±4.56) mm 2 vs. (4.75±2.00) mm 2 , (12.65±5.04) mm 2 vs. (10.44±1.13) mm 2 , (19.51±6.54) mm 2 vs. (17.55±0.30) mm 2 , (28.72±5.45) mm 2 vs. (24.48±1.32) mm 2 , (21.34±4.42) mm 2 vs. (17.72±0.25) mm 2 , (13.00±5.46) mm 2 vs. (12.00±2.88) mm 2 . The statistical analysis of every level was made by T test and the difference of the distribution area between the two tracers were not statistically significant (t=0.705, P=0.519; t=0.743, P=0.499; t=0.517, P=0.656; t=1.310, P=0.260; t=1.416, P=0.292; t=0.281, P=0.793), but the distribution area of LY is slightly more than Gd-DTPA. LSCM imaging technology confirmed partitioned drainage of the brain ISF found by MRI tracer-based method and provided technology and method validation for MRI tracer-based method. LSCM imaging technology with higher contrast and resolution, therefore more sophisticated partitioned drainage of the brain interstitial fluid were got.

A microfluidic brain slice perfusion chamber for multisite recording using penetrating electrodes.

PubMed

Blake, Alexander J; Rodgers, Frank C; Bassuener, Anna; Hippensteel, Joseph A; Pearce, Thomas M; Pearce, Timothy R; Zarnowska, Ewa D; Pearce, Robert A; Williams, Justin C

2010-05-30

To analyze the spatiotemporal dynamics of network activity in a brain tissue slice, it is useful to record simultaneously from multiple locations. When obtained from laminar structures such as the hippocampus or neocortex, multisite recordings also yield information about subcellular current distributions via current source density analysis. Multisite probes developed for in vivo recordings could serve these purposes in vitro, allowing recordings to be obtained from brain slices at sites deeper within the tissue than currently available surface recording methods permit. However, existing recording chambers do not allow for the insertion of lamina-spanning probes that enter through the edges of brain slices. Here, we present a novel brain slice recording chamber design that accomplishes this goal. The device provides a stable microfluidic perfusion environment in which tissue health is optimized by superfusing both surfaces of the slice. Multichannel electrodes can be inserted parallel to the surface of the slice, at any depth relative to the surface. Access is also provided from above for the insertion of additional recording or stimulating electrodes. We illustrate the utility of this recording configuration by measuring current sources and sinks during theta burst stimuli that lead to the induction of long-term potentiation in hippocampal slices. (c) 2010 Elsevier B.V. All rights reserved.

Physiological temperature during brain slicing enhances the quality of acute slice preparations

PubMed Central

Huang, Shiwei; Uusisaari, Marylka Y.

2013-01-01

We demonstrate that brain dissection and slicing using solutions warmed to near-physiological temperature (~ +34°C), greatly enhance slice quality without affecting intrinsic electrophysiological properties of the neurons. Improved slice quality is seen not only when using young (<1 month), but also mature (>2.5 month) mice. This allows easy in vitro patch-clamp experimentation using adult deep cerebellar nuclear slices, which until now have been considered very difficult. As proof of the concept, we compare intrinsic properties of cerebellar nuclear neurons in juvenile (<1 month) and adult (up to 7 months) mice, and confirm that no significant developmental changes occur after the fourth postnatal week. The enhanced quality of brain slices from old animals facilitates experimentation on age-related disorders as well as optogenetic studies requiring long transfection periods. PMID:23630465

Cortical perfusion response to an electrical stimulation of the auditory nerve in profoundly deaf patients: study with technetium-99m hexamethylpropylene amine oxime single photon emission tomography.

PubMed

Le Scao, Y; Robier, A; Baulieu, J L; Beutter, P; Pourcelot, L

1992-01-01

Brain activation procedures associated with single photon emission tomography (SPET) have recently been developed in healthy controls and diseased patients in order to help in their diagnosis and treatment. We investigated the effects of a promontory test (PT) on the cerebral distribution of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) in 7 profoundly deaf patients, 6 PT+ and one PT-. The count variation in the temporal lobe was calculated on 6 coronal slices using the ratio (Rstimulation-Rdeprivation)/Rdeprivation where R = counts in the temporal lobe/whole-brain count. A count increase in the temporal lobe was observed in all patients and was higher in all patients with PT+ than in the patient with PT-. The problems of head positioning and resolution of the system were taken into account, and we considered that the maximal count increment was related to the auditory cortex response to the stimulus. Further clinical investigations with high-resolution systems have to be performed in order to validate this presurgery test in cochlear implant assessment.

Rat brain sagittal organotypic slice cultures as an ex vivo dopamine cell loss system.

PubMed

McCaughey-Chapman, Amy; Connor, Bronwen

2017-02-01

Organotypic brain slice cultures are a useful tool to study neurological function as they provide a more complex, 3-dimensional system than standard 2-dimensional in vitro cell cultures. Building on a previously developed mouse brain slice culture protocol, we have developed a rat sagittal brain slice culture system as an ex vivo model of dopamine cell loss. We show that rat brain organotypic slice cultures remain viable for up to 6 weeks in culture. Using Fluoro-Gold axonal tracing, we demonstrate that the slice 3-dimensional cytoarchitecture is maintained over a 4 week culturing period, with particular focus on the nigrostriatal pathway. Treatment of the cultures with 6-hydroxydopamine and desipramine induces a progressive loss of Fluoro-Gold-positive nigral cells with a sustained loss of tyrosine hydroxylase-positive nigral cells. This recapitulates the pattern of dopaminergic degeneration observed in the rat partial 6-hydroxydopamine lesion model and, most importantly, the progressive pathology of Parkinson's disease. Our slice culture platform provides an advance over other systems, as we demonstrate for the first time 3-dimensional cytoarchitecture maintenance of rat nigrostriatal sagittal slices for up to 6 weeks. Our ex vivo organotypic slice culture system provides a long term cellular platform to model Parkinson's disease, allowing for the elucidation of mechanisms involved in dopaminergic neuron degeneration and the capability to study cellular integration and plasticity ex vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimized 3D stitching algorithm for whole body SPECT based on transition error minimization (TEM)

NASA Astrophysics Data System (ADS)

Cao, Xinhua; Xu, Xiaoyin; Voss, Stephan

2017-02-01

Standard Single Photon Emission Computed Tomography (SPECT) has a limited field of view (FOV) and cannot provide a 3D image of an entire long whole body SPECT. To produce a 3D whole body SPECT image, two to five overlapped SPECT FOVs from head to foot are acquired and assembled using image stitching. Most commercial software from medical imaging manufacturers applies a direct mid-slice stitching method to avoid blurring or ghosting from 3D image blending. Due to intensity changes across the middle slice of overlapped images, direct mid-slice stitching often produces visible seams in the coronal and sagittal views and maximal intensity projection (MIP). In this study, we proposed an optimized algorithm to reduce the visibility of stitching edges. The new algorithm computed, based on transition error minimization (TEM), a 3D stitching interface between two overlapped 3D SPECT images. To test the suggested algorithm, four studies of 2-FOV whole body SPECT were used and included two different reconstruction methods (filtered back projection (FBP) and ordered subset expectation maximization (OSEM)) as well as two different radiopharmaceuticals (Tc-99m MDP for bone metastases and I-131 MIBG for neuroblastoma tumors). Relative transition errors of stitched whole body SPECT using mid-slice stitching and the TEM-based algorithm were measured for objective evaluation. Preliminary experiments showed that the new algorithm reduced the visibility of the stitching interface in the coronal, sagittal, and MIP views. Average relative transition errors were reduced from 56.7% of mid-slice stitching to 11.7% of TEM-based stitching. The proposed algorithm also avoids blurring artifacts by preserving the noise properties of the original SPECT images.

An algorithm based on OmniView technology to reconstruct sagittal and coronal planes of the fetal brain from volume datasets acquired by three-dimensional ultrasound.

PubMed

Rizzo, G; Capponi, A; Pietrolucci, M E; Capece, A; Aiello, E; Mammarella, S; Arduini, D

2011-08-01

To describe a novel algorithm, based on the new display technology 'OmniView', developed to visualize diagnostic sagittal and coronal planes of the fetal brain from volumes obtained by three-dimensional (3D) ultrasonography. We developed an algorithm to image standard neurosonographic planes by drawing dissecting lines through the axial transventricular view of 3D volume datasets acquired transabdominally. The algorithm was tested on 106 normal fetuses at 18-24 weeks of gestation and the visualization rates of brain diagnostic planes were evaluated by two independent reviewers. The algorithm was also applied to nine cases with proven brain defects. The two reviewers, using the algorithm on normal fetuses, found satisfactory images with visualization rates ranging between 71.7% and 96.2% for sagittal planes and between 76.4% and 90.6% for coronal planes. The agreement rate between the two reviewers, as expressed by Cohen's kappa coefficient, was > 0.93 for sagittal planes and > 0.89 for coronal planes. All nine abnormal volumes were identified by a single observer from among a series including normal brains, and eight of these nine cases were diagnosed correctly. This novel algorithm can be used to visualize standard sagittal and coronal planes in the fetal brain. This approach may simplify the examination of the fetal brain and reduce dependency of success on operator skill. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.

An evaluation of overnight fixation to facilitate neuropathological examination in Coroner's autopsies: our experience of over 200 cases.

PubMed

Scott, Ian Stuart; MacDonald, Alastair Wray

2013-01-01

Following recent changes in Coroner's Rules, there has been a desire to examine brains at the time of autopsy, rather than after a prolonged period of immersion fixation. Examination of the fresh brain at postmortem can yield unsatisfactory results where detailed histological examination is required. We aim to provide a compromise, where detailed examination of the brain is possible, without the requirement for prolonged fixation, interference with funeral arrangements and delay in the Coronial process. A retrospective audit of over 200 neuropathology cases requested by HM Coroner for the East Riding of Yorkshire between 2007 and 2010 was performed. The cases consisted of full neuropathology autopsies (n=212) and brains referred by general pathology colleagues (n=26). Of the 238 brains examined, approximately half (n=109) of the brains were sectioned fresh in the mortuary. The remaining brains (n=129) were immersion fixed overnight in 20% formalin prior to cutting and sampling for histology (n=127). The median time for reporting was 31 days (range 1-167; n=101) for brains requiring histology. This equates to a median turnaround time of 1 month for a neuropathological autopsy requiring detailed histology. In all cases, the report was prepared and available to HM Coroner in advance of the Inquest. This method provides reliable histological diagnoses in neuropathological autopsies and does not interfere with funeral arrangements for bereaved families following deaths falling under Coronial jurisdiction. In all cases, the body could be released to relatives, at Coroner's discretion, within two working days of the autopsy.

Development and characterization of an ex-vivo brain slice culture model of chronic wasting disease

USDA-ARS?s Scientific Manuscript database

Prion diseases have long incubation times in vivo, therefore, modeling the diseases ex-vivo will advance the development of rationale-based therapeutic strategies. An organotypic slice culture assay (POSCA) was recently developed for scrapie prions by inoculating mouse cerebellar brain slices with R...

Localized Drug Application and Sub-Second Voltammetric Dopamine Release Measurements in a Brain Slice Perfusion Device

PubMed Central

2015-01-01

The use of fast scan cyclic voltammetry (FSCV) to measure the release and uptake of dopamine (DA) as well as other biogenic molecules in viable brain tissue slices has gained popularity over the last 2 decades. Brain slices have the advantage of maintaining the functional three-dimensional architecture of the neuronal network while also allowing researchers to obtain multiple sets of measurements from a single animal. In this work, we describe a simple, easy-to-fabricate perfusion device designed to focally deliver pharmacological agents to brain slices. The device incorporates a microfluidic channel that runs under the perfusion bath and a microcapillary that supplies fluid from this channel up to the slice. We measured electrically evoked DA release in brain slices before and after the administration of two dopaminergic stimulants, cocaine and GBR-12909. Measurements were collected at two locations, one directly over and the other 500 μm away from the capillary opening. Using this approach, the controlled delivery of drugs to a confined region of the brain slice and the application of this chamber to FSCV measurements, were demonstrated. Moreover, the consumption of drugs was reduced to tens of microliters, which is thousands of times less than traditional perfusion methods. We expect that this simply fabricated device will be useful in providing spatially resolved delivery of drugs with minimum consumption for voltammetric and electrophysiological studies of a variety of biological tissues both in vitro and ex vivo. PMID:24734992

[A modified intracellular labelling technique for high-resolution staining of neuron in 500 microm-thickness brain slice].

PubMed

Zhao, Ming-liang; Liu, Guo-long; Sui, Jian-feng; Ruan, Huai-zhen; Xiong, Ying

2007-05-01

To develop simple but reliable intracellular labelling method for high-resolution visualization of the fine structure of single neurons in brain slice with thickness of 500 microm. Biocytin was introduced into neurons in 500 microm-thickness brain slices while blind whole cell recording. Following processed for histochemistry using the avidin-biotin-complex method, stained slices were mounted in glycerol on special glass slides. Labelled cells were digital photomicrographed every 30 microm and reconstructed with Adobe Photoshop software. After histochemistry, limited background staining was produced. The resolution was so high that fine structure, including branching, termination of individual axons and even spines of neurons could be identified in exquisite detail with optic microscope. With the help of software, the neurons of interest could be reconstructed from a stack of photomicrographs. The modified method provides an easy and reliable approach to revealing the detailed morphological properties of single neurons in 500 microm-thickness brain slice. Without requisition of special equipment, it is suited to be broadly applied.

Organotypic Slice Cultures for Studies of Postnatal Neurogenesis

PubMed Central

Mosa, Adam J.; Wang, Sabrina; Tan, Yao Fang; Wojtowicz, J. Martin

2015-01-01

Here we describe a technique for studying hippocampal postnatal neurogenesis in the rodent brain using the organotypic slice culture technique. This method maintains the characteristic topographical morphology of the hippocampus while allowing direct application of pharmacological agents to the developing hippocampal dentate gyrus. Additionally, slice cultures can be maintained for up to 4 weeks and thus, allow one to study the maturation process of newborn granule neurons. Slice cultures allow for efficient pharmacological manipulation of hippocampal slices while excluding complex variables such as uncertainties related to the deep anatomic location of the hippocampus as well as the blood brain barrier. For these reasons, we sought to optimize organotypic slice cultures specifically for postnatal neurogenesis research. PMID:25867138

Comparison of a modified mid-coronal sectioning technique and Wilson's technique when conducting eye and brain examinations in rabbit teratology studies.

PubMed

Ziejewski, Mary K; Solomon, Howard M; Rendemonti, Joyce; Stanislaus, Dinesh

2015-02-01

There are two methods used when examining fetal rabbit eyes and brain in teratology studies. One method employs prior fixation before serial sectioning (Wilson's technique) and the other uses fresh tissue (mid-coronal sectioning). We modified the mid-coronal sectioning technique to include removal of eyes and brain for closer examination and to increase the number of structures that can be evaluated and compared it to the Wilson's technique. We found that external examination of the head, in conjunction with either sectioning method, is equally sensitive in identifying developmental defects. We evaluated 40,401 New Zealand White (NZW) and Dutch-Belted (DB) rabbit fetuses for external head alterations, of which 28,538 fetuses were further examined for eye and brain alterations using the modified mid-coronal sectioning method (16,675 fetuses) or Wilson's technique (11,863 fetuses). The fetuses were from vehicle control or drug-treated pregnant rabbits in embryo-fetal development studies conducted to meet international regulatory requirements for the development of new drugs. Both methods detected the more common alterations (microphthalmia and dilated lateral cerebral ventricles) and other less common findings (changes in size and/or shape of eye and brain structures). While both methods are equally sensitive at detecting common and rare developmental defects, the modified mid-coronal sectioning technique eliminates the use of chemicals and concomitant fixation artifacts that occur with the Wilson's technique and allows for examination of 100% intact fetuses thereby increasing potential for detecting eye and brain alterations as these findings occur infrequently in rabbits. © 2015 Wiley Periodicals, Inc.

Ruminant organotypic brain-slice cultures as a model for the investigation of CNS listeriosis

PubMed Central

Guldimann, Claudia; Lejeune, Beatrice; Hofer, Sandra; Leib, Stephen L; Frey, Joachim; Zurbriggen, Andreas; Seuberlich, Torsten; Oevermann, Anna

2012-01-01

Central nervous system (CNS) infections in ruminant livestock, such as listeriosis, are of major concern for veterinary and public health. To date, no host-specific in vitro models for ruminant CNS infections are available. Here, we established and evaluated the suitability of organotypic brain-slices of ruminant origin as in vitro model to study mechanisms of Listeria monocytogenes CNS infection. Ruminants are frequently affected by fatal listeric rhombencephalitis that closely resembles the same condition occurring in humans. Better insight into host–pathogen interactions in ruminants is therefore of interest, not only from a veterinary but also from a public health perspective. Brains were obtained at the slaughterhouse, and hippocampal and cerebellar brain-slices were cultured up to 49 days. Viability as well as the composition of cell populations was assessed weekly. Viable neurons, astrocytes, microglia and oligodendrocytes were observed up to 49 days in vitro. Slice cultures were infected with L. monocytogenes, and infection kinetics were monitored. Infected brain cells were identified by double immunofluorescence, and results were compared to natural cases of listeric rhombencephalitis. Similar to the natural infection, infected brain-slices showed focal replication of L. monocytogenes and bacteria were predominantly observed in microglia, but also in astrocytes, and associated with axons. These results demonstrate that organotypic brain-slice cultures of bovine origin survive for extended periods and can be infected easily with L. monocytogenes. Therefore, they are a suitable model to study aspects of host–pathogen interaction in listeric encephalitis and potentially in other neuroinfectious diseases. PMID:22804762

In vivo rat deep brain imaging using photoacoustic computed tomography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lin, Li; Li, Lei; Zhu, Liren; Hu, Peng; Wang, Lihong V.

2017-03-01

The brain has been likened to a great stretch of unknown territory consisting of a number of unexplored continents. Small animal brain imaging plays an important role charting that territory. By using 1064 nm illumination from the side, we imaged the full coronal depth of rat brains in vivo. The experiment was performed using a real-time full-ring-array photoacoustic computed tomography (PACT) imaging system, which achieved an imaging depth of 11 mm and a 100 μm radial resolution. Because of the fast imaging speed of the full-ring-array PACT system, no animal motion artifact was induced. The frame rate of the system was limited by the laser repetition rate (50 Hz). In addition to anatomical imaging of the blood vessels in the brain, we continuously monitored correlations between the two brain hemispheres in one of the coronal planes. The resting states in the coronal plane were measured before and after stroke ligation surgery at a neck artery.

Visualizing Iron Deposition in Multiple Sclerosis Cadaver Brains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habib, A.C.; Zheng, W.; Haacke, E.M.

To visualize and validate iron deposition in two cases of multiple sclerosis using rapid scanning X-Ray Fluorescence (RS-XRF) and Susceptibility Weighted Imaging (SWI). Two (2) coronal cadaver brain slices from patients clinically diagnosed with multiple sclerosis underwent magnetic resonance imaging (MRI), specifically SWI to image iron content. To confirm the presence of iron deposits and the absence of zinc-rich myelin in lesions, iron and zinc were mapped using RS-XRF. MS lesions were visualized using FLAIR and correlated with the absence of zinc by XRF. XRF and SWI showed that in the first MS case, there were large iron deposits proximalmore » to the draining vein of the caudate nucleus as well as iron deposits associated with blood vessels throughout the globus pallidus. Less iron was seen in association with lesions than in the basal ganglia. The presence of larger amounts of iron correlated reasonably well between RS-XRF and SWI. In the second case, the basal ganglia appeared normal and acute perivascular iron deposition was absent. Perivascular iron deposition is seen in some but not all MS cases, giving credence to the use of SWI to assess iron involvement in MS pathology in vivo.« less

Visualizing Iron Deposition in Multiple Sclerosis Cadaver Brains

NASA Astrophysics Data System (ADS)

Habib, Charbel A.; Zheng, Weili; Mark Haacke, E.; Webb, Sam; Nichol, Helen

2010-07-01

Aim: To visualize and validate iron deposition in two cases of multiple sclerosis using rapid scanning X-Ray Fluorescence (RS-XRF) and Susceptibility Weighted Imaging (SWI). Material and Methods: Two (2) coronal cadaver brain slices from patients clinically diagnosed with multiple sclerosis underwent magnetic resonance imaging (MRI), specifically SWI to image iron content. To confirm the presence of iron deposits and the absence of zinc-rich myelin in lesions, iron and zinc were mapped using RS-XRF. Results: MS lesions were visualized using FLAIR and correlated with the absence of zinc by XRF. XRF and SWI showed that in the first MS case, there were large iron deposits proximal to the draining vein of the caudate nucleus as well as iron deposits associated with blood vessels throughout the globus pallidus. Less iron was seen in association with lesions than in the basal ganglia. The presence of larger amounts of iron correlated reasonably well between RS-XRF and SWI. In the second case, the basal ganglia appeared normal and acute perivascular iron deposition was absent. Conclusion: Perivascular iron deposition is seen in some but not all MS cases, giving credence to the use of SWI to assess iron involvement in MS pathology in vivo.

Optimization of Brain T2 Mapping Using Standard CPMG Sequence In A Clinical Scanner

NASA Astrophysics Data System (ADS)

Hnilicová, P.; Bittšanský, M.; Dobrota, D.

2014-04-01

In magnetic resonance imaging, transverse relaxation time (T2) mapping is a useful quantitative tool enabling enhanced diagnostics of many brain pathologies. The aim of our study was to test the influence of different sequence parameters on calculated T2 values, including multi-slice measurements, slice position, interslice gap, echo spacing, and pulse duration. Measurements were performed using standard multi-slice multi-echo CPMG imaging sequence on a 1.5 Tesla routine whole body MR scanner. We used multiple phantoms with different agarose concentrations (0 % to 4 %) and verified the results on a healthy volunteer. It appeared that neither the pulse duration, the size of interslice gap nor the slice shift had any impact on the T2. The measurement accuracy was increased with shorter echo spacing. Standard multi-slice multi-echo CPMG protocol with the shortest echo spacing, also the smallest available interslice gap (100 % of slice thickness) and shorter pulse duration was found to be optimal and reliable for calculating T2 maps in the human brain.

Chronic Ketamine Reduces the Peak Frequency of Gamma Oscillations in Mouse Prefrontal Cortex Ex vivo.

PubMed

McNally, James M; McCarley, Robert W; Brown, Ritchie E

2013-01-01

Abnormalities in EEG gamma band oscillations (GBO, 30-80 Hz) serve as a prominent biomarker of schizophrenia (Sz), associated with positive, negative, and cognitive symptoms. Chronic, subanesthetic administration of antagonists of N-methyl-D-aspartate receptors (NMDAR), such as ketamine, elicits behavioral effects, and alterations in cortical interneurons similar to those observed in Sz. However, the chronic effects of ketamine on neocortical GBO are unknown. Thus, here we examine the effects of chronic (five daily i.p. injections) application of ketamine (5 and 30 mg/kg) and the more specific NMDAR antagonist, MK-801 (0.02, 0.5, and 2 mg/kg), on neocortical GBO ex vivo. Oscillations were generated by focal application of the glutamate receptor agonist, kainate (KA), in coronal brain slices containing the prelimbic cortex. This region constitutes the rodent analog of the human dorsolateral prefrontal cortex, a brain region strongly implicated in Sz-pathophysiology. Here we report the novel finding that chronic ketamine elicits a reduction in the peak oscillatory frequency of KA-elicited oscillations (from 47 to 40 Hz at 30 mg/kg). Moreover, the power of GBO in the 40-50 Hz band was reduced. These findings are reminiscent of both the reduced resonance frequency and power of cortical oscillations observed in Sz clinical studies. Surprisingly, MK-801 had no significant effect, suggesting care is needed when equating Sz-like behavioral effects elicited by different NMDAR antagonists to alterations in GBO activity. We conclude that chronic ketamine in the mouse mimics GBO abnormalities observed in Sz patients. Use of this ex vivo slice model may be useful in testing therapeutic compounds which rescue these GBO abnormalities.

MO-F-CAMPUS-J-04: Tissue Segmentation-Based MR Electron Density Mapping Method for MR-Only Radiation Treatment Planning of Brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, H; Lee, Y; Ruschin, M

2015-06-15

Purpose: Automatically derive electron density of tissues using MR images and generate a pseudo-CT for MR-only treatment planning of brain tumours. Methods: 20 stereotactic radiosurgery (SRS) patients’ T1-weighted MR images and CT images were retrospectively acquired. First, a semi-automated tissue segmentation algorithm was developed to differentiate tissues with similar MR intensities and large differences in electron densities. The method started with approximately 12 slices of manually contoured spatial regions containing sinuses and airways, then air, bone, brain, cerebrospinal fluid (CSF) and eyes were automatically segmented using edge detection and anatomical information including location, shape, tissue uniformity and relative intensity distribution.more » Next, soft tissues - muscle and fat were segmented based on their relative intensity histogram. Finally, intensities of voxels in each segmented tissue were mapped into their electron density range to generate pseudo-CT by linearly fitting their relative intensity histograms. Co-registered CT was used as a ground truth. The bone segmentations of pseudo-CT were compared with those of co-registered CT obtained by using a 300HU threshold. The average distances between voxels on external edges of the skull of pseudo-CT and CT in three axial, coronal and sagittal slices with the largest width of skull were calculated. The mean absolute electron density (in Hounsfield unit) difference of voxels in each segmented tissues was calculated. Results: The average of distances between voxels on external skull from pseudo-CT and CT were 0.6±1.1mm (mean±1SD). The mean absolute electron density differences for bone, brain, CSF, muscle and fat are 78±114 HU, and 21±8 HU, 14±29 HU, 57±37 HU, and 31±63 HU, respectively. Conclusion: The semi-automated MR electron density mapping technique was developed using T1-weighted MR images. The generated pseudo-CT is comparable to that of CT in terms of anatomical position of tissues and similarity of electron density assignment. This method can allow MR-only treatment planning.« less

Positron Spectroscopy Investigation of Normal Brain Section and Brain Section with Glioma Derived from a Rat Glioma Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, SH.; Ballmann, C.; Quarles, C. A.

2009-03-10

The application of positron annihilation lifetime spectroscopy (PALS) and Doppler broadening spectroscopy (DBS) to the study of animal or human tissue has only recently been reported [G. Liu, et al. phys. stat. sol. (C) 4, Nos. 10, 3912-3915 (2007)]. We have initiated a study of normal brain section and brain section with glioma derived from a rat glioma model. For the rat glioma model, 200,000 C6 cells were implanted in the basal ganglion of adult Sprague Dawley rats. The rats were sacrificed at 21 days after implantation. The brains were harvested, sliced into 2 mm thick coronal sections, and fixedmore » in 4% formalin. PALS lifetime runs were made with the samples soaked in formalin, and there was not significant evaporation of formalin during the runs. The lifetime spectra were analyzed into two lifetime components. While early results suggested a small decrease in ortho-Positronium (o-Ps) pickoff lifetime between the normal brain section and brain section with glioma, further runs with additional samples have showed no statistically significant difference between the normal and tumor tissue for this type of tumor. The o-Ps lifetime in formalin alone was lower than either the normal tissue or glioma sample. So annihilation in the formalin absorbed in the samples would lower the o-Ps lifetime and this may have masked any difference due to the glioma itself. DBS was also used to investigate the difference in positronium formation between tumor and normal tissue. Tissue samples are heterogeneous and this needs to be carefully considered if PALS and DBS are to become useful tools in distinguishing tissue samples.« less

Characterization of cortical neuronal and glial alterations during culture of organotypic whole brain slices from neonatal and mature mice.

PubMed

Staal, Jerome A; Alexander, Samuel R; Liu, Yao; Dickson, Tracey D; Vickers, James C

2011-01-01

Organotypic brain slice culturing techniques are extensively used in a wide range of experimental procedures and are particularly useful in providing mechanistic insights into neurological disorders or injury. The cellular and morphological alterations associated with hippocampal brain slice cultures has been well established, however, the neuronal response of mouse cortical neurons to culture is not well documented. In the current study, we compared the cell viability, as well as phenotypic and protein expression changes in cortical neurons, in whole brain slice cultures from mouse neonates (P4-6), adolescent animals (P25-28) and mature adults (P50+). Cultures were prepared using the membrane interface method. Propidium iodide labeling of nuclei (due to compromised cell membrane) and AlamarBlue™ (cell respiration) analysis demonstrated that neonatal tissue was significantly less vulnerable to long-term culture in comparison to the more mature brain tissues. Cultures from P6 animals showed a significant increase in the expression of synaptic markers and a decrease in growth-associated proteins over the entire culture period. However, morphological analysis of organotypic brain slices cultured from neonatal tissue demonstrated that there were substantial changes to neuronal and glial organization within the neocortex, with a distinct loss of cytoarchitectural stratification and increased GFAP expression (p<0.05). Additionally, cultures from neonatal tissue had no glial limitans and, after 14 DIV, displayed substantial cellular protrusions from slice edges, including cells that expressed both glial and neuronal markers. In summary, we present a substantial evaluation of the viability and morphological changes that occur in the neocortex of whole brain tissue cultures, from different ages, over an extended period of culture.

5D CNS+ Software for Automatically Imaging Axial, Sagittal, and Coronal Planes of Normal and Abnormal Second-Trimester Fetal Brains.

PubMed

Rizzo, Giuseppe; Capponi, Alessandra; Persico, Nicola; Ghi, Tullio; Nazzaro, Giovanni; Boito, Simona; Pietrolucci, Maria Elena; Arduini, Domenico

2016-10-01

The purpose of this study was to test new 5D CNS+ software (Samsung Medison Co, Ltd, Seoul, Korea), which is designed to image axial, sagittal, and coronal planes of the fetal brain from volumes obtained by 3-dimensional sonography. The study consisted of 2 different steps. First in a prospective study, 3-dimensional fetal brain volumes were acquired in 183 normal consecutive singleton pregnancies undergoing routine sonographic examinations at 18 to 24 weeks' gestation. The 5D CNS+ software was applied, and the percentage of adequate visualization of brain diagnostic planes was evaluated by 2 independent observers. In the second step, the software was also tested in 22 fetuses with cerebral anomalies. In 180 of 183 fetuses (98.4%), 5D CNS+ successfully reconstructed all of the diagnostic planes. Using the software on healthy fetuses, the observers acknowledged the presence of diagnostic images with visualization rates ranging from 97.7% to 99.4% for axial planes, 94.4% to 97.7% for sagittal planes, and 92.2% to 97.2% for coronal planes. The Cohen κ coefficient was analyzed to evaluate the agreement rates between the observers and resulted in values of 0.96 or greater for axial planes, 0.90 or greater for sagittal planes, and 0.89 or greater for coronal planes. All 22 fetuses with brain anomalies were identified among a series that also included healthy fetuses, and in 21 of the 22 cases, a correct diagnosis was made. 5D CNS+ was efficient in successfully imaging standard axial, sagittal, and coronal planes of the fetal brain. This approach may simplify the examination of the fetal central nervous system and reduce operator dependency.

Establishment and Characterization of a Tumor Stem Cell-Based Glioblastoma Invasion Model.

PubMed

Jensen, Stine Skov; Meyer, Morten; Petterson, Stine Asferg; Halle, Bo; Rosager, Ann Mari; Aaberg-Jessen, Charlotte; Thomassen, Mads; Burton, Mark; Kruse, Torben A; Kristensen, Bjarne Winther

2016-01-01

Glioblastoma is the most frequent and malignant brain tumor. Recurrence is inevitable and most likely connected to tumor invasion and presence of therapy resistant stem-like tumor cells. The aim was therefore to establish and characterize a three-dimensional in vivo-like in vitro model taking invasion and tumor stemness into account. Glioblastoma stem cell-like containing spheroid (GSS) cultures derived from three different patients were established and characterized. The spheroids were implanted in vitro into rat brain slice cultures grown in stem cell medium and in vivo into brains of immuno-compromised mice. Invasion was followed in the slice cultures by confocal time-lapse microscopy. Using immunohistochemistry, we compared tumor cell invasion as well as expression of proliferation and stem cell markers between the models. We observed a pronounced invasion into brain slice cultures both by confocal time-lapse microscopy and immunohistochemistry. This invasion closely resembled the invasion in vivo. The Ki-67 proliferation indexes in spheroids implanted into brain slices were lower than in free-floating spheroids. The expression of stem cell markers varied between free-floating spheroids, spheroids implanted into brain slices and tumors in vivo. The established invasion model kept in stem cell medium closely mimics tumor cell invasion into the brain in vivo preserving also to some extent the expression of stem cell markers. The model is feasible and robust and we suggest the model as an in vivo-like model with a great potential in glioma studies and drug discovery.

Ammonia-induced brain swelling and neurotoxicity in an organotypic slice model

PubMed Central

Back, Adam; Tupper, Kelsey Y.; Bai, Tao; Chiranand, Paulpoj; Goldenberg, Fernando D.; Frank, Jeffrey I.; Brorson, James R.

2013-01-01

Objectives Acute liver failure produces cerebral dysfunction and edema, mediated in part by elevated ammonia concentrations, often leading to coma and death. The pathophysiology of cerebral edema in acute liver failure is incompletely understood. In vitro models of the cerebral effects of acute liver failure have predominately consisted of dissociated astrocyte cultures or acute brain slices. We describe a stable long-term culture model incorporating both neural and glial elements in a three-dimensional tissue structure offering significant advantages to the study of astrocytic-neuronal interactions in the pathophysiology of cerebral edema and dysfunction in acute liver failure. Methods We utilized chronic organotypic slice cultures from mouse forebrain, applying ammonium acetate in iso-osmolar fashion for 72 hours. Imaging of slice thickness to assess for tissue swelling was accomplished in living slices with optical coherence tomography, and confocal microscopy of fluorescence immunochemical and histochemical staining served to assess astrocyte and neuronal numbers, morphology, and volume in the fixed brain slices. Results Ammonia exposure at 1–10 mM produced swelling of immunochemically-identified astrocytes, and at 10 mM resulted in macroscopic tissue swelling, with slice thickness increasing by about 30%. Astrocytes were unchanged in number. In contrast, 10 mM ammonia treatment severely disrupted neuronal morphology and reduced neuronal survival at 72 hours by one-half. Discussion Elevated ammonia produces astrocytic swelling, tissue swelling, and neuronal toxicity in cerebral tissues. Ammonia-treated organotypic brain slice cultures provide an in vitro model of cerebral effects of conditions relevant to acute liver failure, applicable to pathophysiological investigations. PMID:22196764

Effects of Orientation and Anisometry of Magnetic Resonance Imaging Acquisitions on Diffusion Tensor Imaging and Structural Connectomes.

PubMed

Tudela, Raúl; Muñoz-Moreno, Emma; López-Gil, Xavier; Soria, Guadalupe

2017-01-01

Diffusion-weighted imaging (DWI) quantifies water molecule diffusion within tissues and is becoming an increasingly used technique. However, it is very challenging as correct quantification depends on many different factors, ranging from acquisition parameters to a long pipeline of image processing. In this work, we investigated the influence of voxel geometry on diffusion analysis, comparing different acquisition orientations as well as isometric and anisometric voxels. Diffusion-weighted images of one rat brain were acquired with four different voxel geometries (one isometric and three anisometric in different directions) and three different encoding orientations (coronal, axial and sagittal). Diffusion tensor scalar measurements, tractography and the brain structural connectome were analyzed for each of the 12 acquisitions. The acquisition direction with respect to the main magnetic field orientation affected the diffusion results. When the acquisition slice-encoding direction was not aligned with the main magnetic field, there were more artifacts and a lower signal-to-noise ratio that led to less anisotropic tensors (lower fractional anisotropic values), producing poorer quality results. The use of anisometric voxels generated statistically significant differences in the values of diffusion metrics in specific regions. It also elicited differences in tract reconstruction and in different graph metric values describing the brain networks. Our results highlight the importance of taking into account the geometric aspects of acquisitions, especially when comparing diffusion data acquired using different geometries.

Functionalized graphene oxide as a drug carrier for loading pirfenidone in treatment of subarachnoid hemorrhage.

PubMed

Yang, Lijun; Wang, Feng; Han, Haie; Yang, Liang; Zhang, Gengshen; Fan, Zhenzeng

2015-05-01

Subarachnoid hemorrhage (SAH) is a life-threatening disease that causes high morbidity and mortality. Pirfenidone is a SAH drug that prevents secondary bleeding and cerebral infarction. To improve its therapeutic efficacy, this study aimed to employ a functionalized graphene oxide nanosheet (FGO) as a drug carrier loading pirfenidone to treat SAH. The graphene oxide nanosheet was introduced with transcription activator peptide (Tat), followed by functionalization with methoxy polyethylene glycol (mPEG) and loading with pirfenidone. The pirfenidone-loaded FGO (pirfenidone-FGO) exhibits better treatment efficacy than the single pirfenidone due to more effective loading and controlled release of the drug in tissue. The introduction of Tat and mPEG onto GO nanosheet contributes to the ability to cross the blood-brain barrier and the stability in blood circulation of the drug. At lower pH values, the highly efficient release of the drug from the pirfenidone-FGO exerts effective treatment to acidic inflammatory lesion after severe SAH. Besides its treatment function, FGO is also shown as a strong near infrared absorbing material which can be applied in photoacoustic imaging, allowing rapid real-time monitoring with deep resolution of brain tissues after SAH. The treatment efficacy of pirfenidone-FGO for central nervous system injuries is further demonstrated by hematoxylin and eosin staining of coronal brain slices, as well as measurements of brain water content and blood-brain barrier permeability. Our study supports the potential of FGO in clinical application in treatment of SAH. Copyright © 2015 Elsevier B.V. All rights reserved.

3D Data Mapping and Real-Time Experiment Control and Visualization in Brain Slices.

PubMed

Navarro, Marco A; Hibbard, Jaime V K; Miller, Michael E; Nivin, Tyler W; Milescu, Lorin S

2015-10-20

Here, we propose two basic concepts that can streamline electrophysiology and imaging experiments in brain slices and enhance data collection and analysis. The first idea is to interface the experiment with a software environment that provides a 3D scene viewer in which the experimental rig, the brain slice, and the recorded data are represented to scale. Within the 3D scene viewer, the user can visualize a live image of the sample and 3D renderings of the recording electrodes with real-time position feedback. Furthermore, the user can control the instruments and visualize their status in real time. The second idea is to integrate multiple types of experimental data into a spatial and temporal map of the brain slice. These data may include low-magnification maps of the entire brain slice, for spatial context, or any other type of high-resolution structural and functional image, together with time-resolved electrical and optical signals. The entire data collection can be visualized within the 3D scene viewer. These concepts can be applied to any other type of experiment in which high-resolution data are recorded within a larger sample at different spatial and temporal coordinates. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Tensor-product kernel-based representation encoding joint MRI view similarity.

PubMed

Alvarez-Meza, A; Cardenas-Pena, D; Castro-Ospina, A E; Alvarez, M; Castellanos-Dominguez, G

2014-01-01

To support 3D magnetic resonance image (MRI) analysis, a marginal image similarity (MIS) matrix holding MR inter-slice relationship along every axis view (Axial, Coronal, and Sagittal) can be estimated. However, mutual inference from MIS view information poses a difficult task since relationships between axes are nonlinear. To overcome this issue, we introduce a Tensor-Product Kernel-based Representation (TKR) that allows encoding brain structure patterns due to patient differences, gathering all MIS matrices into a single joint image similarity framework. The TKR training strategy is carried out into a low dimensional projected space to get less influence of voxel-derived noise. Obtained results for classifying the considered patient categories (gender and age) on real MRI database shows that the proposed TKR training approach outperforms the conventional voxel-wise sum of squared differences. The proposed approach may be useful to support MRI clustering and similarity inference tasks, which are required on template-based image segmentation and atlas construction.

Cortical gyrification in autistic and Asperger disorders: a preliminary magnetic resonance imaging study.

PubMed

Jou, Roger J; Minshew, Nancy J; Keshavan, Matcheri S; Hardan, Antonio Y

2010-12-01

The validity of Asperger disorder as a distinct syndrome from autism is unclear partly because of the paucity of differentiating neurobiological evidence. Frontal lobe cortical folding between these disorders was compared using the gyrification index. Twenty-three boys underwent structural magnetic resonance imaging: 6 with high-functioning autism, 9 with Asperger disorder, and 8 controls. Using the first coronal slice anterior to the corpus callosum, total and outer cortical contours were traced to calculate the gyrification index. This index was also calculated for superior and inferior regions to examine dorsolateral prefrontal and orbitofrontal cortices, respectively. Analysis of variance revealed differences in the left inferior gyrification index, which was higher in the autism group compared with Asperger and control groups. There were no differences in age, intelligence quotient, and brain volume. These preliminary findings suggest that cortical folding may be abnormally high in the frontal lobe in autism but not Asperger disorder, suggesting distinct frontal lobe neuropathology.

Intracellular ATP influences synaptic plasticity in area CA1 of rat hippocampus via metabolism to adenosine and activity-dependent activation of adenosine A1 receptors.

PubMed

zur Nedden, Stephanie; Hawley, Simon; Pentland, Naomi; Hardie, D Grahame; Doney, Alexander S; Frenguelli, Bruno G

2011-04-20

The extent to which brain slices reflect the energetic status of the in vivo brain has been a subject of debate. We addressed this issue to investigate the recovery of energetic parameters and adenine nucleotides in rat hippocampal slices and the influence this has on synaptic transmission and plasticity. We show that, although adenine nucleotide levels recover appreciably within 10 min of incubation, it takes 3 h for a full recovery of the energy charge (to ≥ 0.93) and that incubation of brain slices at 34°C results in a significantly higher ATP/AMP ratio and a threefold lower activity of AMP-activated protein kinase compared with slices incubated at room temperature. Supplementation of artificial CSF with d-ribose and adenine (Rib/Ade) increased the total adenine nucleotide pool of brain slices, which, when corrected for the influence of the dead cut edges, closely approached in vivo values. Rib/Ade did not affect basal synaptic transmission or paired-pulse facilitation but did inhibit long-term potentiation (LTP) induced by tetanic or weak theta-burst stimulation. This decrease in LTP was reversed by strong theta-burst stimulation or antagonizing the inhibitory adenosine A(1) receptor suggesting that the elevated tissue ATP levels had resulted in greater activity-dependent adenosine release during LTP induction. This was confirmed by direct measurement of adenosine release with adenosine biosensors. These observations provide new insight into the recovery of adenine nucleotides after slice preparation, the sources of loss of such compounds in brain slices, the means by which to restore them, and the functional consequences of doing so.

The Brain Tourniquet: Physiological Isolation of Brain Regions Damaged by Traumatic Head Injury

DTIC Science & Technology

2008-06-19

brain slices were treated after injury with either a nootropic agent ( aniracetam , cyclothiazide, IDRA 21, or 1-BCP) or the antiepileptic drug...tourniquet approach. Four well-known nootropic agents were evaluated: aniracetam , a pyrrolidione analog that slows non-NMDA (AMPA/kainate) receptor...to improve cognition in rats [Stdubli et al., 1994], and has more potent effects than aniracetam in rat brain slices [Arai et al., 1994]. In

Slice-to-Volume Nonrigid Registration of Histological Sections to MR Images of the Human Brain

PubMed Central

Osechinskiy, Sergey; Kruggel, Frithjof

2011-01-01

Registration of histological images to three-dimensional imaging modalities is an important step in quantitative analysis of brain structure, in architectonic mapping of the brain, and in investigation of the pathology of a brain disease. Reconstruction of histology volume from serial sections is a well-established procedure, but it does not address registration of individual slices from sparse sections, which is the aim of the slice-to-volume approach. This study presents a flexible framework for intensity-based slice-to-volume nonrigid registration algorithms with a geometric transformation deformation field parametrized by various classes of spline functions: thin-plate splines (TPS), Gaussian elastic body splines (GEBS), or cubic B-splines. Algorithms are applied to cross-modality registration of histological and magnetic resonance images of the human brain. Registration performance is evaluated across a range of optimization algorithms and intensity-based cost functions. For a particular case of histological data, best results are obtained with a TPS three-dimensional (3D) warp, a new unconstrained optimization algorithm (NEWUOA), and a correlation-coefficient-based cost function. PMID:22567290

Development of a high-throughput brain slice method for studying drug distribution in the central nervous system.

PubMed

Fridén, Markus; Ducrozet, Frederic; Middleton, Brian; Antonsson, Madeleine; Bredberg, Ulf; Hammarlund-Udenaes, Margareta

2009-06-01

New, more efficient methods of estimating unbound drug concentrations in the central nervous system (CNS) combine the amount of drug in whole brain tissue samples measured by conventional methods with in vitro estimates of the unbound brain volume of distribution (V(u,brain)). Although the brain slice method is the most reliable in vitro method for measuring V(u,brain), it has not previously been adapted for the needs of drug discovery research. The aim of this study was to increase the throughput and optimize the experimental conditions of this method. Equilibrium of drug between the buffer and the brain slice within the 4 to 5 h of incubation is a fundamental requirement. However, it is difficult to meet this requirement for many of the extensively binding, lipophilic compounds in drug discovery programs. In this study, the dimensions of the incubation vessel and mode of stirring influenced the equilibration time, as did the amount of brain tissue per unit of buffer volume. The use of cassette experiments for investigating V(u,brain) in a linear drug concentration range increased the throughput of the method. The V(u,brain) for the model compounds ranged from 4 to 3000 ml . g brain(-1), and the sources of variability are discussed. The optimized setup of the brain slice method allows precise, robust estimation of V(u,brain) for drugs with diverse properties, including highly lipophilic compounds. This is a critical step forward for the implementation of relevant measurements of CNS exposure in the drug discovery setting.

Evaluating glymphatic pathway function utilizing clinically relevant intrathecal infusion of CSF tracer.

PubMed

Yang, Lijun; Kress, Benjamin T; Weber, Harris J; Thiyagarajan, Meenakshisundaram; Wang, Baozhi; Deane, Rashid; Benveniste, Helene; Iliff, Jeffrey J; Nedergaard, Maiken

2013-05-01

Neurodegenerative diseases such as Alzheimer's are associated with the aggregation of endogenous peptides and proteins that contribute to neuronal dysfunction and loss. The glymphatic system, a brain-wide perivascular pathway along which cerebrospinal fluid (CSF) and interstitial fluid (ISF) rapidly exchange, has recently been identified as a key contributor to the clearance of interstitial solutes from the brain, including amyloid β. These findings suggest that measuring changes in glymphatic pathway function may be an important prognostic for evaluating neurodegenerative disease susceptibility or progression. However, no clinically acceptable approach to evaluate glymphatic pathway function in humans has yet been developed. Time-sequenced ex vivo fluorescence imaging of coronal rat and mouse brain slices was performed at 30-180 min following intrathecal infusion of CSF tracer (Texas Red- dextran-3, MW 3 kD; FITC- dextran-500, MW 500 kD) into the cisterna magna or lumbar spine. Tracer influx into different brain regions (cortex, white matter, subcortical structures, and hippocampus) in rat was quantified to map the movement of CSF tracer following infusion along both routes, and to determine whether glymphatic pathway function could be evaluated after lumbar intrathecal infusion. Following lumbar intrathecal infusions, small molecular weight TR-d3 entered the brain along perivascular pathways and exchanged broadly with the brain ISF, consistent with the initial characterization of the glymphatic pathway in mice. Large molecular weight FITC-d500 remained confined to the perivascular spaces. Lumbar intrathecal infusions exhibited a reduced and delayed peak parenchymal fluorescence intensity compared to intracisternal infusions. Lumbar intrathecal contrast delivery is a clinically useful approach that could be used in conjunction with dynamic contrast enhanced MRI nuclear imaging to assess glymphatic pathway function in humans.

Evaluating glymphatic pathway function utilizing clinically relevant intrathecal infusion of CSF tracer

PubMed Central

2013-01-01

Background Neurodegenerative diseases such as Alzheimer’s are associated with the aggregation of endogenous peptides and proteins that contribute to neuronal dysfunction and loss. The glymphatic system, a brain-wide perivascular pathway along which cerebrospinal fluid (CSF) and interstitial fluid (ISF) rapidly exchange, has recently been identified as a key contributor to the clearance of interstitial solutes from the brain, including amyloid β. These findings suggest that measuring changes in glymphatic pathway function may be an important prognostic for evaluating neurodegenerative disease susceptibility or progression. However, no clinically acceptable approach to evaluate glymphatic pathway function in humans has yet been developed. Methods Time-sequenced ex vivo fluorescence imaging of coronal rat and mouse brain slices was performed at 30–180 min following intrathecal infusion of CSF tracer (Texas Red- dextran-3, MW 3 kD; FITC- dextran-500, MW 500 kD) into the cisterna magna or lumbar spine. Tracer influx into different brain regions (cortex, white matter, subcortical structures, and hippocampus) in rat was quantified to map the movement of CSF tracer following infusion along both routes, and to determine whether glymphatic pathway function could be evaluated after lumbar intrathecal infusion. Results Following lumbar intrathecal infusions, small molecular weight TR-d3 entered the brain along perivascular pathways and exchanged broadly with the brain ISF, consistent with the initial characterization of the glymphatic pathway in mice. Large molecular weight FITC-d500 remained confined to the perivascular spaces. Lumbar intrathecal infusions exhibited a reduced and delayed peak parenchymal fluorescence intensity compared to intracisternal infusions. Conclusion Lumbar intrathecal contrast delivery is a clinically useful approach that could be used in conjunction with dynamic contrast enhanced MRI nuclear imaging to assess glymphatic pathway function in humans. PMID:23635358

Organotypic hippocampal slice culture from the adult mouse brain: a versatile tool for translational neuropsychopharmacology.

PubMed

Kim, Hyunjeong; Kim, Eosu; Park, Minsun; Lee, Eun; Namkoong, Kee

2013-03-05

One of the most significant barriers towards translational neuropsychiatry would be an unavailability of living brain tissues. Although organotypic brain tissue culture could be a useful alternative enabling observation of temporal changes induced by various drugs in living brain tissues, a proper method to establish a stable organotypic brain slice culture system using adult (rather than neonatal) hippocampus has been still elusive. In this study, we evaluated our simple method using the serum-free culture medium for successful adult organotypic hippocampal slice culture. Several tens of hippocampal slices from a single adult mouse (3-5 months old) were cultured in serum-free versus serum-containing conventional culture medium for 30 days and underwent various experiments to validate the effects of the existence of serum in the culture medium. Neither the excessive regression of neuronal viability nor metabolic deficiency was observed in the serum-free medium culture in contrast to the serum-containing medium culture. Despite such viability, newly generated immature neurons were scarcely detected in the serum-free culture, suggesting that the original neurons in the brain slice persist rather than being replaced by neurogenesis. Key structural features of in vivo neural tissue constituting astrocytes, neural processes, and pre- and post-synapses were also well preserved in the serum-free culture. In conclusion, using the serum-free culture medium, the adult hippocampal slice culture system will serve as a promising ex vivo tool for various fields of neuroscience, especially for studies on aging-related neuropsychiatric disorders or for high throughput screening of potential agents working against such disorders. Copyright © 2012 Elsevier Inc. All rights reserved.

Ischemic Brain Injury Leads to Brain Edema via Hyperthermia-Induced TRPV4 Activation.

PubMed

Hoshi, Yutaka; Okabe, Kohki; Shibasaki, Koji; Funatsu, Takashi; Matsuki, Norio; Ikegaya, Yuji; Koyama, Ryuta

2018-06-20

Brain edema is characterized by an increase in net brain water content, which results in an increase in brain volume. Although brain edema is associated with a high fatality rate, the cellular and molecular processes of edema remain largely unclear. Here, we developed an in vitro model of ischemic stroke-induced edema in which male mouse brain slices were treated with oxygen-glucose deprivation (OGD) to mimic ischemia. We continuously measured the cross-sectional area of the brain slice for 150 min under macroscopic microscopy, finding that OGD induces swelling of brain slices. OGD-induced swelling was prevented by pharmacologically blocking or genetically knocking out the transient receptor potential vanilloid 4 (TRPV4), a member of the thermosensitive TRP channel family. Because TRPV4 is activated at around body temperature and its activation is enhanced by heating, we next elevated the temperature of the perfusate in the recording chamber, finding that hyperthermia induces swelling via TRPV4 activation. Furthermore, using the temperature-dependent fluorescence lifetime of a fluorescent-thermosensitive probe, we confirmed that OGD treatment increases the temperature of brain slices through the activation of glutamate receptors. Finally, we found that brain edema following traumatic brain injury was suppressed in TRPV4-deficient male mice in vivo Thus, our study proposes a novel mechanism: hyperthermia activates TRPV4 and induces brain edema after ischemia. SIGNIFICANCE STATEMENT Brain edema is characterized by an increase in net brain water content, which results in an increase in brain volume. Although brain edema is associated with a high fatality rate, the cellular and molecular processes of edema remain unclear. Here, we developed an in vitro model of ischemic stroke-induced edema in which mouse brain slices were treated with oxygen-glucose deprivation. Using this system, we showed that the increase in brain temperature and the following activation of the thermosensitive cation channel TRPV4 (transient receptor potential vanilloid 4) are involved in the pathology of edema. Finally, we confirmed that TRPV4 is involved in brain edema in vivo using TRPV4-deficient mice, concluding that hyperthermia activates TRPV4 and induces brain edema after ischemia. Copyright © 2018 the authors 0270-6474/18/385700-10$15.00/0.

Oxidative Damage in the Guinea Pig Hippocampal Slice

DTIC Science & Technology

1989-01-01

Original Contribution OXIDATIVE DAMAGE IN THE GUINEA PIG HIPPOCAMPAL SLICE TIRRY C. Pnt.N1.iAR’ and KATIlRNN L. Nt-t-t- Physiology Department. Armed Forces...responses in the hippocampal slice isolated from the brains of guinea pigs . Electrical stim- ulation of afferents to neurons of the CA I region of...from the brains be secreted by the microglia invading a region of in- of euthanized male Hartley guinea pigs as previously Jury. ’ Another possible

Chaos Control of Epileptiform Bursting in the Brain

NASA Astrophysics Data System (ADS)

Slutzky, M. W.; Cvitanovic, P.; Mogul, D. J.

Epilepsy, defined as recurrent seizures, is a pathological state of the brain that afflicts over one percent of the world's population. Seizures occur as populations of neurons in the brain become overly synchronized. Although pharmacological agents are the primary treatment for preventing or reducing the incidence of these seizures, over 30% of epilepsy cases are not adequately helped by standard medical therapies. Several groups are exploring the use of electrical stimulation to terminate or prevent epileptic seizures. One experimental model used to test these algorithms is the brain slice where a select region of the brain is cut and kept viable in a well-oxygenated artificial cerebrospinal fluid. Under certain conditions, such slices may be made to spontaneously and repetitively burst, thereby providing an in vitro model of epilepsy. In this chapter, we discuss our efforts at applying chaos analysis and chaos control algorithms for manipulating this seizure-like behavior in a brain slice model. These techniques may provide a nonlinear control pathway for terminating or potentially preventing epileptic seizures in the whole brain.

A simple water-immersion condenser for imaging living brain slices on an inverted microscope.

PubMed

Prusky, G T

1997-09-05

Due to some physical limitations of conventional condensers, inverted compound microscopes are not optimally suited for imaging living brain slices with transmitted light. Herein is described a simple device that converts an inverted microscope into an effective tool for this application by utilizing an objective as a condenser. The device is mounted on a microscope in place of the condenser, is threaded to accept a water immersion objective, and has a slot for a differential interference contrast (DIC) slider. When combined with infrared video techniques, this device allows an inverted microscope to effectively image living cells within thick brain slices in an open perfusion chamber.

3D knee segmentation based on three MRI sequences from different planes.

PubMed

Zhou, L; Chav, R; Cresson, T; Chartrand, G; de Guise, J

2016-08-01

In clinical practice, knee MRI sequences with 3.5~5 mm slice distance in sagittal, coronal, and axial planes are often requested for the knee examination since its acquisition is faster than high-resolution MRI sequence in a single plane, thereby reducing the probability of motion artifact. In order to take advantage of the three sequences from different planes, a 3D segmentation method based on the combination of three knee models obtained from the three sequences is proposed in this paper. In the method, the sub-segmentation is respectively performed with sagittal, coronal, and axial MRI sequence in the image coordinate system. With each sequence, an initial knee model is hierarchically deformed, and then the three deformed models are mapped to reference coordinate system defined by the DICOM standard and combined to obtain a patient-specific model. The experimental results verified that the three sub-segmentation results can complement each other, and their integration can compensate for the insufficiency of boundary information caused by 3.5~5 mm gap between consecutive slices. Therefore, the obtained patient-specific model is substantially more accurate than each sub-segmentation results.

Accuracy of limited four-slice CT-scan in diagnosis of chronic rhinosinusitis.

PubMed

Zojaji, R; Nekooei, S; Naghibi, S; Mazloum Farsi Baf, M; Jalilian, R; Masoomi, M

2015-12-01

Chronic rhinosinusitis (CRS) is a common chronic health condition worldwide. Standard CT-scan is the method of choice for diagnosis of CRS but its high price and considerable radiation exposure have limited its application. The main goal of this study was to evaluate the accuracy of limited four-slice coronal CT-scan in the diagnosis of CRS. This cross-sectional study was conducted on 46 patients with CRS, for one year, based on American Society of Head and Neck Surgery criteria. All patients received the preoperative standard and four-slice CT-scans, after which endoscopic sinus surgery was performed. Findings of four-slice CT-scans were compared with those of conventional CT-scan and the sensitivity and specificity of four-slice CT-scan and its agreement with conventional CT-scan was calculated. In this study, 46 patients including 32 males (69.6%) and 14 females (30.46%) with a mean age of 33 and standard deviation of 9 years, were evaluated. Sensitivity and specificity of four-slice CT-scan were 97.5% and 100%, respectively. Also, positive predictive value (PPV) and negative predictive value (NPV) of four-slice CT was 100% and 85.71%, respectively. There was a strong agreement between four-slice CT and conventional CT findings. Considering the high sensitivity and specificity of four-slice CT-scan and strong agreement with conventional CT-scan in the diagnosis of CRS and the lower radiation exposure and cost, application of this method is suggested for both diagnosis and treatment follow-up in CRS. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

A novel application of the fluorescent dye bis-ANS for labeling neurons in acute brain slices.

PubMed

Mozes, Emese; Hunya, Akos; Toth, Aniko; Ayaydin, Ferhan; Penke, Botond; Datki, Zsolt L

2011-10-10

The cell-impermeant oligomer-(e.g. beta-amyloid-, or tubulin-) specific fluorescent dye, bis-ANS (4,4'-bis-1-anilinonaphtalene-8-sulfonate), was successfully used for labeling mechanically damaged but still viable neuron bodies, neurites and neurite cross sections in acute brain slices. Acute hippocampal brain slices of rats were co-stained with bis-ANS and the cell-impermeant, DNA-specific dye propidium iodide (PI) and were then analyzed using fluorescence and confocal microscopes. Both the neuron bodies and the neurites were found to exhibit increased fluorescence intensities, suggesting that using this method they can be detected more easily. In addition, bis-ANS showed good region - but not cell specific co-localization with the neuron-specific fluorescent dye Dil (1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate). These two dyes label different neuronal structures: Dil binds specifically to intact cell membranes while bis-ANS can enter cells with compromised cell membranes and then stain the microtubules in the cytoplasm. For a quick (10min) staining of acute brain slices with bis-ANS both HEPES and NaHCO(3) were needed in order to achieve high signal intensity. Labeling with bis-ANS fluorescent dye is an easy method for imaging the neuronal structures on the surface of acute brain slices. Copyright © 2011 Elsevier Inc. All rights reserved.

Maintaining network activity in submerged hippocampal slices: importance of oxygen supply.

PubMed

Hájos, Norbert; Ellender, Tommas J; Zemankovics, Rita; Mann, Edward O; Exley, Richard; Cragg, Stephanie J; Freund, Tamás F; Paulsen, Ole

2009-01-01

Studies in brain slices have provided a wealth of data on the basic features of neurons and synapses. In the intact brain, these properties may be strongly influenced by ongoing network activity. Although physiologically realistic patterns of network activity have been successfully induced in brain slices maintained in interface-type recording chambers, they have been harder to obtain in submerged-type chambers, which offer significant experimental advantages, including fast exchange of pharmacological agents, visually guided patch-clamp recordings, and imaging techniques. Here, we investigated conditions for the emergence of network oscillations in submerged slices prepared from the hippocampus of rats and mice. We found that the local oxygen level is critical for generation and propagation of both spontaneously occurring sharp wave-ripple oscillations and cholinergically induced fast oscillations. We suggest three ways to improve the oxygen supply to slices under submerged conditions: (i) optimizing chamber design for laminar flow of superfusion fluid; (ii) increasing the flow rate of superfusion fluid; and (iii) superfusing both surfaces of the slice. These improvements to the recording conditions enable detailed studies of neurons under more realistic conditions of network activity, which are essential for a better understanding of neuronal network operation.

Preclinical Characterization of 18F-MK-6240, a Promising PET Tracer for In Vivo Quantification of Human Neurofibrillary Tangles.

PubMed

Hostetler, Eric D; Walji, Abbas M; Zeng, Zhizhen; Miller, Patricia; Bennacef, Idriss; Salinas, Cristian; Connolly, Brett; Gantert, Liza; Haley, Hyking; Holahan, Marie; Purcell, Mona; Riffel, Kerry; Lohith, Talakad G; Coleman, Paul; Soriano, Aileen; Ogawa, Aimie; Xu, Serena; Zhang, Xiaoping; Joshi, Elizabeth; Della Rocca, Joseph; Hesk, David; Schenk, David J; Evelhoch, Jeffrey L

2016-10-01

A PET tracer is desired to help guide the discovery and development of disease-modifying therapeutics for neurodegenerative diseases characterized by neurofibrillary tangles (NFTs), the predominant tau pathology in Alzheimer disease (AD). We describe the preclinical characterization of the NFT PET tracer 18 F-MK-6240. In vitro binding studies were conducted with 3 H-MK-6240 in tissue slices and homogenates from cognitively normal and AD human brain donors to evaluate tracer affinity and selectivity for NFTs. Immunohistochemistry for phosphorylated tau was performed on human brain slices for comparison with 3 H-MK-6240 binding patterns on adjacent brain slices. PET studies were performed with 18 F-MK-6240 in monkeys to evaluate tracer kinetics and distribution in the brain. 18 F-MK-6240 monkey PET studies were conducted after dosing with unlabeled MK-6240 to evaluate tracer binding selectivity in vivo. The 3 H-MK-6240 binding pattern was consistent with the distribution of phosphorylated tau in human AD brain slices. 3 H-MK-6240 bound with high affinity to human AD brain cortex homogenates containing abundant NFTs but bound poorly to amyloid plaque-rich, NFT-poor AD brain homogenates. 3 H-MK-6240 showed no displaceable binding in the subcortical regions of human AD brain slices and in the hippocampus/entorhinal cortex of non-AD human brain homogenates. In monkey PET studies, 18 F-MK-6240 displayed rapid and homogeneous distribution in the brain. The 18 F-MK-6240 volume of distribution stabilized rapidly, indicating favorable tracer kinetics. No displaceable binding was observed in self-block studies in rhesus monkeys, which do not natively express NFTs. Moderate defluorination was observed as skull uptake. 18 F-MK-6240 is a promising PET tracer for the in vivo quantification of NFTs in AD patients. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Long Term Synaptic Plasticity and Learning in Neuronal Networks

DTIC Science & Technology

1989-01-14

Videomicroscopy and synaptic physiology of cultured hippocampal slices. Soc, Neurosci. Abstr. 14:246, 1988. Griffith, W.H., Brown, T.H. and Johnston, D...Chapman, P.F., Chang, V., and Brown, T.H. . Videomicroscopy of acute brain slices from hippocampus and amygdala. Brain Res. Bull, 21: 373-383, 1988

Visualizing Iron Deposition in Multiple Sclerosis Cadaver Brains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habib, Charbel A.; Zheng Weili; Mark Haacke, E.

Aim: To visualize and validate iron deposition in two cases of multiple sclerosis using rapid scanning X-Ray Fluorescence (RS-XRF) and Susceptibility Weighted Imaging (SWI). Material and Methods: Two (2) coronal cadaver brain slices from patients clinically diagnosed with multiple sclerosis underwent magnetic resonance imaging (MRI), specifically SWI to image iron content. To confirm the presence of iron deposits and the absence of zinc-rich myelin in lesions, iron and zinc were mapped using RS-XRF. Results: MS lesions were visualized using FLAIR and correlated with the absence of zinc by XRF. XRF and SWI showed that in the first MS case, theremore » were large iron deposits proximal to the draining vein of the caudate nucleus as well as iron deposits associated with blood vessels throughout the globus pallidus. Less iron was seen in association with lesions than in the basal ganglia. The presence of larger amounts of iron correlated reasonably well between RS-XRF and SWI. In the second case, the basal ganglia appeared normal and acute perivascular iron deposition was absent. Conclusion: Perivascular iron deposition is seen in some but not all MS cases, giving credence to the use of SWI to assess iron involvement in MS pathology in vivo.« less

Hyaline cartilage thickness in radiographically normal cadaveric hips: comparison of spiral CT arthrographic and macroscopic measurements.

PubMed

Wyler, Annabelle; Bousson, Valérie; Bergot, Catherine; Polivka, Marc; Leveque, Eric; Vicaut, Eric; Laredo, Jean-Denis

2007-02-01

To assess spiral multidetector computed tomographic (CT) arthrography for the depiction of cartilage thickness in hips without cartilage loss, with evaluation of anatomic slices as the reference standard. Permission to perform imaging studies in cadaveric specimens of individuals who had willed their bodies to science was obtained from the institutional review board. Two independent observers measured the femoral and acetabular hyaline cartilage thickness of 12 radiographically normal cadaveric hips (from six women and five men; age range at death, 52-98 years; mean, 76.5 years) on spiral multidetector CT arthrographic reformations and on coronal anatomic slices. Regions of cartilage loss at gross or histologic examination were excluded. CT arthrographic and anatomic measurements in the coronal plane were compared by using Bland-Altman representation and a paired t test. Differences between mean cartilage thicknesses at the points of measurement were tested by means of analysis of variance. Interobserver and intraobserver reproducibilities were determined. At CT arthrography, mean cartilage thickness ranged from 0.32 to 2.53 mm on the femoral head and from 0.95 to 3.13 mm on the acetabulum. Observers underestimated cartilage thickness in the coronal plane by 0.30 mm +/- 0.52 (mean +/- standard error) at CT arthrography (P < .001) compared with the anatomic reference standard. Ninety-five percent of the differences between CT arthrography and anatomic values ranged from -1.34 to 0.74 mm. The difference between mean cartilage thicknesses at the different measurement points was significant for coronal spiral multidetector CT arthrography and anatomic measurement of the femoral head and acetabulum and for sagittal and transverse CT arthrography of the femoral head (P < .001). Changes in cartilage thickness from the periphery to the center of the joint ("gradients") were found by means of spiral multidetector CT arthrography and anatomic measurement. Spiral multidetector CT arthrography depicts cartilage thickness gradients in radiographically normal cadaveric hips. (c) RSNA, 2007.

Targeting neurotransmitter receptors with nanoparticles in vivo allows single-molecule tracking in acute brain slices

NASA Astrophysics Data System (ADS)

Varela, Juan A.; Dupuis, Julien P.; Etchepare, Laetitia; Espana, Agnès; Cognet, Laurent; Groc, Laurent

2016-03-01

Single-molecule imaging has changed the way we understand many biological mechanisms, particularly in neurobiology, by shedding light on intricate molecular events down to the nanoscale. However, current single-molecule studies in neuroscience have been limited to cultured neurons or organotypic slices, leaving as an open question the existence of fast receptor diffusion in intact brain tissue. Here, for the first time, we targeted dopamine receptors in vivo with functionalized quantum dots and were able to perform single-molecule tracking in acute rat brain slices. We propose a novel delocalized and non-inflammatory way of delivering nanoparticles (NPs) in vivo to the brain, which allowed us to label and track genetically engineered surface dopamine receptors in neocortical neurons, revealing inherent behaviour and receptor activity regulations. We thus propose a NP-based platform for single-molecule studies in the living brain, opening new avenues of research in physiological and pathological animal models.

Organotypic slice cultures containing the preBötzinger complex generate respiratory-like rhythms

PubMed Central

Phillips, Wiktor S.; Herly, Mikkel; Del Negro, Christopher A.

2015-01-01

Study of acute brain stem slice preparations in vitro has advanced our understanding of the cellular and synaptic mechanisms of respiratory rhythm generation, but their inherent limitations preclude long-term manipulation and recording experiments. In the current study, we have developed an organotypic slice culture preparation containing the preBötzinger complex (preBötC), the core inspiratory rhythm generator of the ventrolateral brain stem. We measured bilateral synchronous network oscillations, using calcium-sensitive fluorescent dyes, in both ventrolateral (presumably the preBötC) and dorsomedial regions of slice cultures at 7–43 days in vitro. These calcium oscillations appear to be driven by periodic bursts of inspiratory neuronal activity, because whole cell recordings from ventrolateral neurons in culture revealed inspiratory-like drive potentials, and no oscillatory activity was detected from glial fibrillary associated protein-expressing astrocytes in cultures. Acute slices showed a burst frequency of 10.9 ± 4.2 bursts/min, which was not different from that of brain stem slice cultures (13.7 ± 10.6 bursts/min). However, slice cocultures that include two cerebellar explants placed along the dorsolateral border of the brainstem displayed up to 193% faster burst frequency (22.4 ± 8.3 bursts/min) and higher signal amplitude (340%) compared with acute slices. We conclude that preBötC-containing slice cultures retain inspiratory-like rhythmic function and therefore may facilitate lines of experimentation that involve extended incubation (e.g., genetic transfection or chronic drug exposure) while simultaneously being amenable to imaging and electrophysiology at cellular, synaptic, and network levels. PMID:26655824

Volumetric analysis of maxillary sinuses of Zulu and European crania by helical, multislice computed tomography.

PubMed

Fernandes, C L

2004-11-01

The volumes of the maxillary sinuses are of interest to surgeons operating endoscopically as variation in maxillary sinus volume may mean variation in anatomical landmarks. Other surgical disciplines, such as dentistry, maxillo-facial surgery and plastic surgery, may benefit from this information. To compare the maxillary sinus volumes of dried crania from cadavers of European and Zulu descent, with respect to ethnic group and gender. Helical, multislice computed tomography (CT) was performed using 1-mm coronal slices. The area for each slice was obtained by tracing the outline of each slice. The CT machine calculated a volume by totalling the slices for each sinus. Ethnic and gender variations were found in the different groups. It was found that European crania had significantly larger antral volumes than Zulu crania and men had larger volumes than women. Race and gender interaction was also assessed, as was maxillary sinus side. A variation in maxillary sinus volume between different ethnic groups and genders exists, and surgeons operating in this region should be aware of this.

Recording and Modulation of Epileptiform Activity in Rodent Brain Slices Coupled to Microelectrode Arrays.

PubMed

Panuccio, Gabriella; Colombi, Ilaria; Chiappalone, Michela

2018-05-15

Temporal lobe epilepsy (TLE) is the most common partial complex epileptic syndrome and the least responsive to medications. Deep brain stimulation (DBS) is a promising approach when pharmacological treatment fails or neurosurgery is not recommended. Acute brain slices coupled to microelectrode arrays (MEAs) represent a valuable tool to study neuronal network interactions and their modulation by electrical stimulation. As compared to conventional extracellular recording techniques, they provide the added advantages of a greater number of observation points and a known inter-electrode distance, which allow studying the propagation path and speed of electrophysiological signals. However, tissue oxygenation may be greatly impaired during MEA recording, requiring a high perfusion rate, which comes at the cost of decreased signal-to-noise ratio and higher oscillations in the experimental temperature. Electrical stimulation further stresses the brain tissue, making it difficult to pursue prolonged recording/stimulation epochs. Moreover, electrical modulation of brain slice activity needs to target specific structures/pathways within the brain slice, requiring that electrode mapping be easily and quickly performed live during the experiment. Here, we illustrate how to perform the recording and electrical modulation of 4-aminopyridine (4AP)-induced epileptiform activity in rodent brain slices using planar MEAs. We show that the brain tissue obtained from mice outperforms rat brain tissue and is thus better suited for MEA experiments. This protocol guarantees the generation and maintenance of a stable epileptiform pattern that faithfully reproduces the electrophysiological features observed with conventional field potential recording, persists for several hours, and outlasts sustained electrical stimulation for prolonged epochs. Tissue viability throughout the experiment is achieved thanks to the use of a small-volume custom recording chamber allowing for laminar flow and quick solution exchange even at low (1 mL/min) perfusion rates. Quick MEA mapping for real-time monitoring and selection of stimulating electrodes is performed by a custom graphic user interface (GUI).

Live imaging of mitosis in the developing mouse embryonic cortex.

PubMed

Pilaz, Louis-Jan; Silver, Debra L

2014-06-04

Although of short duration, mitosis is a complex and dynamic multi-step process fundamental for development of organs including the brain. In the developing cerebral cortex, abnormal mitosis of neural progenitors can cause defects in brain size and function. Hence, there is a critical need for tools to understand the mechanisms of neural progenitor mitosis. Cortical development in rodents is an outstanding model for studying this process. Neural progenitor mitosis is commonly examined in fixed brain sections. This protocol will describe in detail an approach for live imaging of mitosis in ex vivo embryonic brain slices. We will describe the critical steps for this procedure, which include: brain extraction, brain embedding, vibratome sectioning of brain slices, staining and culturing of slices, and time-lapse imaging. We will then demonstrate and describe in detail how to perform post-acquisition analysis of mitosis. We include representative results from this assay using the vital dye Syto11, transgenic mice (histone H2B-EGFP and centrin-EGFP), and in utero electroporation (mCherry-α-tubulin). We will discuss how this procedure can be best optimized and how it can be modified for study of genetic regulation of mitosis. Live imaging of mitosis in brain slices is a flexible approach to assess the impact of age, anatomy, and genetic perturbation in a controlled environment, and to generate a large amount of data with high temporal and spatial resolution. Hence this protocol will complement existing tools for analysis of neural progenitor mitosis.

Brain tumor segmentation in MR slices using improved GrowCut algorithm

NASA Astrophysics Data System (ADS)

Ji, Chunhong; Yu, Jinhua; Wang, Yuanyuan; Chen, Liang; Shi, Zhifeng; Mao, Ying

2015-12-01

The detection of brain tumor from MR images is very significant for medical diagnosis and treatment. However, the existing methods are mostly based on manual or semiautomatic segmentation which are awkward when dealing with a large amount of MR slices. In this paper, a new fully automatic method for the segmentation of brain tumors in MR slices is presented. Based on the hypothesis of the symmetric brain structure, the method improves the interactive GrowCut algorithm by further using the bounding box algorithm in the pre-processing step. More importantly, local reflectional symmetry is used to make up the deficiency of the bounding box method. After segmentation, 3D tumor image is reconstructed. We evaluate the accuracy of the proposed method on MR slices with synthetic tumors and actual clinical MR images. Result of the proposed method is compared with the actual position of simulated 3D tumor qualitatively and quantitatively. In addition, our automatic method produces equivalent performance as manual segmentation and the interactive GrowCut with manual interference while providing fully automatic segmentation.

Fast and precise thermoregulation system in physiological brain slice experiment

NASA Astrophysics Data System (ADS)

Sheu, Y. H.; Young, M. S.

1995-12-01

We have developed a fast and precise thermoregulation system incorporated within a physiological experiment on a brain slice. The thermoregulation system is used to control the temperature of a recording chamber in which the brain slice is placed. It consists of a single-chip microcomputer, a set command module, a display module, and an FLC module. A fuzzy control algorithm was developed and a fuzzy logic controller then designed for achieving fast, smooth thermostatic performance and providing precise temperature control with accuracy to 0.1 °C, from room temperature through 42 °C (experimental temperature range). The fuzzy logic controller is implemented by microcomputer software and related peripheral hardware circuits. Six operating modes of thermoregulation are offered with the system and this can be further extended according to experimental needs. The test results of this study demonstrate that the fuzzy control method is easily implemented by a microcomputer and also verifies that this method provides a simple way to achieve fast and precise high-performance control of a nonlinear thermoregulation system in a physiological brain slice experiment.

Neuronal Deletion of Caspase 8 Protects against Brain Injury in Mouse Models of Controlled Cortical Impact and Kainic Acid-Induced Excitotoxicity

PubMed Central

Krajewska, Maryla; You, Zerong; Rong, Juan; Kress, Christina; Huang, Xianshu; Yang, Jinsheng; Kyoda, Tiffany; Leyva, Ricardo; Banares, Steven; Hu, Yue; Sze, Chia-Hung; Whalen, Michael J.; Salmena, Leonardo; Hakem, Razqallah; Head, Brian P.; Reed, John C.; Krajewski, Stan

2011-01-01

Background Acute brain injury is an important health problem. Given the critical position of caspase 8 at the crossroads of cell death pathways, we generated a new viable mouse line (Ncasp8 −/−), in which the gene encoding caspase 8 was selectively deleted in neurons by cre-lox system. Methodology/Principal Findings Caspase 8 deletion reduced rates of neuronal cell death in primary neuronal cultures and in whole brain organotypic coronal slice cultures prepared from 4 and 8 month old mice and cultivated up to 14 days in vitro. Treatments of cultures with recombinant murine TNFα (100 ng/ml) or TRAIL (250 ng/mL) plus cyclohexamide significantly protected neurons against cell death induced by these apoptosis-inducing ligands. A protective role of caspase 8 deletion in vivo was also demonstrated using a controlled cortical impact (CCI) model of traumatic brain injury (TBI) and seizure-induced brain injury caused by kainic acid (KA). Morphometric analyses were performed using digital imaging in conjunction with image analysis algorithms. By employing virtual images of hundreds of brain sections, we were able to perform quantitative morphometry of histological and immunohistochemical staining data in an unbiased manner. In the TBI model, homozygous deletion of caspase 8 resulted in reduced lesion volumes, improved post-injury motor performance, superior learning and memory retention, decreased apoptosis, diminished proteolytic processing of caspases and caspase substrates, and less neuronal degeneration, compared to wild type, homozygous cre, and caspase 8-floxed control mice. In the KA model, Ncasp8 −/− mice demonstrated superior survival, reduced seizure severity, less apoptosis, and reduced caspase 3 processing. Uninjured aged knockout mice showed improved learning and memory, implicating a possible role for caspase 8 in cognitive decline with aging. Conclusions Neuron-specific deletion of caspase 8 reduces brain damage and improves post-traumatic functional outcomes, suggesting an important role for this caspase in pathophysiology of acute brain trauma. PMID:21957448

Alterations of brain grey matter density and olfactory bulb volume in patients with olfactory loss after traumatic brain injury.

PubMed

Han, Pengfei; Winkler, Nicole; Hummel, Cornelia; Hähner, Antje; Gerber, Johannes; Hummel, Thomas

2018-04-27

Olfactory loss and traumatic brain injury (TBI) both lead to anatomical brain alterations in humans. Little research has been done on the structural brain changes for TBI patients with olfactory loss. Using voxel-based morphometry, the grey matter (GM) density was examined for twenty-two TBI patients with hyposmia, twenty-four TBI patients with anosmia, and twenty-two age-matched controls. Olfactory bulb (OB) volumes were measured by manual segmentation of acquired T2 weighted coronal slices using a standardized protocol. Brain lesions in the olfactory relevant areas were also examined for TBI patients. Results showed that patients with anosmia have more frequent lesions in the OB, orbitofrontal cortex (OFC) and the temporal lobe pole, as compared to patients with hyposmia. GM density in the primary olfactory area was decreased in both groups of patients. In addition, compared to controls, patients with anosmia showed GM density reduction in several secondary olfactory eloquent regions, including the gyrus rectus, medial OFC, anterior cingulate cortex, insula, and cerebellum. However, patients with hyposmia showed a lesser degree of GM reduction compared to healthy controls. Smaller OB volumes were found for patients with olfactory loss as compared to controls. TBI patients with anosmia had the smallest OB volumes which were caused by the lesions for OB. In addition, post-TBI duration was negatively correlated with GM density in the secondary olfactory areas in patients with hyposmia, but was positively correlated with GM density in the frontal and temporal gyrus in patients with anosmia. The GM density and OB volume reduction among TBI patients with olfactory loss was largely depend on the location and severity of brain lesions in olfactory relevant regions. Longer post-TBI duration had an impact on brain GM density changes, which indicate a decreased olfactory function in patients with hyposmia and possible compensatory mechanisms in patients with anosmia.

Acquisition of thin coronal sectional dataset of cadaveric liver.

PubMed

Lou, Li; Liu, Shu Wei; Zhao, Zhen Mei; Tang, Yu Chun; Lin, Xiang Tao

2014-04-01

To obtain the thin coronal sectional anatomic dataset of the liver by using digital freezing milling technique. The upper abdomen of one Chinese adult cadaver was selected as the specimen. After CT and MRI examinations verification of absent liver lesions, the specimen was embedded with gelatin in stand erect position and frozen under profound hypothermia, and the specimen was then serially sectioned from anterior to posterior layer by layer with digital milling machine in the freezing chamber. The sequential images were captured by means of a digital camera and the dataset was imported to imaging workstation. The thin serial section of the liver added up to 699 layers with each layer being 0.2 mm in thickness. The shape, location, structure, intrahepatic vessels and adjacent structures of the liver was displayed clearly on each layer of the coronal sectional slice. CT and MR images through the body were obtained at 1.0 and 3.0 mm intervals, respectively. The methodology reported here is an adaptation of the milling methods previously described, which is a new data acquisition method for sectional anatomy. The thin coronal sectional anatomic dataset of the liver obtained by this technique is of high precision and good quality.

Examining the Complex Regulation and Drug-Induced Plasticity of Dopamine Release and Uptake Using Voltammetry in Brain Slices

PubMed Central

2013-01-01

Fast scan cyclic voltammetry in brain slices (slice voltammetry) has been used over the last several decades to increase substantially our understanding of the complex local regulation of dopamine release and uptake in the striatum. This technique is routinely used for the study of changes that occur in the dopamine system associated with various disease states and pharmacological treatments, and to study mechanisms of local circuitry regulation of dopamine terminal function. In the context of this Review, we compare the relative advantages of voltammetry using striatal slice preparations versus in vivo preparations, and highlight recent advances in our understanding of dopamine release and uptake in the striatum specifically from studies that use slice voltammetry in drug-naïve animals and animals with a history of psychostimulant self-administration. PMID:23581570

Relationship Between the Lateral Center-Edge Angle and 3-Dimensional Acetabular Coverage.

PubMed

Wylie, James D; Kapron, Ashley L; Peters, Christopher L; Aoki, Stephen K; Maak, Travis G

2017-04-01

The lateral center-edge angle (LCEA) is an important measurement in understanding acetabular morphology and has had multiple interpretations. Misunderstanding of the LCEA and its relationship with acetabular 3-dimensional (3D) morphology may result in misdiagnosis and poor outcomes. To determine the discrepancy between bone-edge and sourcil-edge LCEA measurements on anteroposterior (AP) radiographs and to determine the 3D anatomic location of the sourcil-edge and bone-edge LCEA measurements. Cohort study (diagnosis); Level of evidence, 2. The LCEA was measured on radiographs to both the sourcil-edge and bone-edge on AP images of 60 symptomatic hips. On computed tomography (CT), coronal slices producing an LCEA matching the magnitude of each AP LCEA were identified. These coronal slices were mapped to a sagittal image of the acetabulum, which was divided into a standard clockface (3 = anterior, 12 = superior). We identified clockface locations corresponding to the AP sourcil-edge and bone-edge LCEA measurements. Paired t tests identified differences in magnitude and location of the bone and sourcil LCEAs. Limits of agreement were calculated for the differences between measures. Intraclass correlation coefficients (ICCs) assessed inter- and intraobserver repeatability. On the AP radiographs, the bone-edge LCEA was a mean 4.7° (95% CI, -4.0° to 13.3°) greater than the sourcil-edge LCEA ( P < .001). On CT, the sagittal clockface location of the sourcil-edge LCEA was more anterior compared with the sagittal clockface location of the maximum bone-edge LCEA (1:03 ± 0:42 vs 12:06 ± 0:30, respectively; P < .001). In hips with a difference >5° between sourcil-edge and bone-edge measurements, the coronal CT slice corresponding to the sourcil-edge LCEA was significantly more anterior (1:26 ± 0:35) than the CT slice corresponding to the bone-edge LCEA (11:46 ± 0:29; P < .001). This significant difference was similar in location but less pronounced in hips with a difference ≤5°: the sourcil-edge LCEA occurred at 12:50 ± 0:40, while the bone-edge LCEA occurred at 12:00 ± 0:11 ( P < .001). Interobserver repeatability was excellent for all LCEA and clockface location measurements (all ICCs >0.82). The sourcil-edge LCEA represents anterosuperior acetabular coverage while the bone-edge LCEA represents superior/lateral coverage. This information can be used in preoperative evaluation of and perioperative planning for hip preservation procedures.

The impact of computed tomography slice thickness on the assessment of stereotactic, 3D conformal and intensity-modulated radiotherapy of brain tumors.

PubMed

Caivano, R; Fiorentino, A; Pedicini, P; Califano, G; Fusco, V

2014-05-01

To evaluate radiotherapy treatment planning accuracy by varying computed tomography (CT) slice thickness and tumor size. CT datasets from patients with primary brain disease and metastatic brain disease were selected. Tumor volumes ranging from about 2.5 to 100 cc and CT scan at different slice thicknesses (1, 2, 4, 6 and 10 mm) were used to perform treatment planning (1-, 2-, 4-, 6- and 10-CT, respectively). For any slice thickness, a conformity index (CI) referring to 100, 98, 95 and 90 % isodoses and tumor size was computed. All the CI and volumes obtained were compared to evaluate the impact of CT slice thickness on treatment plans. The smallest volumes reduce significantly if defined on 1-CT with respect to 4- and 6-CT, while the CT slice thickness does not affect target definition for the largest volumes. The mean CI for all the considered isodoses and CT slice thickness shows no statistical differences when 1-CT is compared to 2-CT. Comparing the mean CI of 1- with 4-CT and 1- with 6-CT, statistical differences appear only for the smallest volumes with respect to 100, 98 and 95 % isodoses-the CI for 90 % isodose being not statistically significant for all the considered PTVs. The accuracy of radiotherapy tumor volume definition depends on CT slice thickness. To achieve a better tumor definition and dose coverage, 1- and 2-CT would be suitable for small targets, while 4- and 6-CT are suitable for the other volumes.

Analysis of acute brain slices by electron microscopy: a correlative light-electron microscopy workflow based on Tokuyasu cryo-sectioning.

PubMed

Loussert Fonta, Celine; Leis, Andrew; Mathisen, Cliff; Bouvier, David S; Blanchard, Willy; Volterra, Andrea; Lich, Ben; Humbel, Bruno M

2015-01-01

Acute brain slices are slices of brain tissue that are kept vital in vitro for further recordings and analyses. This tool is of major importance in neurobiology and allows the study of brain cells such as microglia, astrocytes, neurons and their inter/intracellular communications via ion channels or transporters. In combination with light/fluorescence microscopies, acute brain slices enable the ex vivo analysis of specific cells or groups of cells inside the slice, e.g. astrocytes. To bridge ex vivo knowledge of a cell with its ultrastructure, we developed a correlative microscopy approach for acute brain slices. The workflow begins with sampling of the tissue and precise trimming of a region of interest, which contains GFP-tagged astrocytes that can be visualised by fluorescence microscopy of ultrathin sections. The astrocytes and their surroundings are then analysed by high resolution scanning transmission electron microscopy (STEM). An important aspect of this workflow is the modification of a commercial cryo-ultramicrotome to observe the fluorescent GFP signal during the trimming process. It ensured that sections contained at least one GFP astrocyte. After cryo-sectioning, a map of the GFP-expressing astrocytes is established and transferred to correlation software installed on a focused ion beam scanning electron microscope equipped with a STEM detector. Next, the areas displaying fluorescence are selected for high resolution STEM imaging. An overview area (e.g. a whole mesh of the grid) is imaged with an automated tiling and stitching process. In the final stitched image, the local organisation of the brain tissue can be surveyed or areas of interest can be magnified to observe fine details, e.g. vesicles or gold labels on specific proteins. The robustness of this workflow is contingent on the quality of sample preparation, based on Tokuyasu's protocol. This method results in a reasonable compromise between preservation of morphology and maintenance of antigenicity. Finally, an important feature of this approach is that the fluorescence of the GFP signal is preserved throughout the entire preparation process until the last step before electron microscopy. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Gonadal Steroids: Effects on Excitability of Hippocampal Pyramidal Cells

NASA Astrophysics Data System (ADS)

Teyler, Timothy J.; Vardaris, Richard M.; Lewis, Deborah; Rawitch, Allen B.

1980-08-01

Electrophysiological field potentials from hippocampal slices of rat brain show sex-linked differences in response to 1 × 10-10M concentrations of estradiol and testosterone added to the incubation medium. Slices from male rats show increased excitability to estradiol and not to testosterone. Slices from female rats are not affected by estradiol, but slices from female rats in diestrus show increased excitability in response to testosterone whereas slices from females in proestrus show decreased excitability.

An automatic method of brain tumor segmentation from MRI volume based on the symmetry of brain and level set method

NASA Astrophysics Data System (ADS)

Li, Xiaobing; Qiu, Tianshuang; Lebonvallet, Stephane; Ruan, Su

2010-02-01

This paper presents a brain tumor segmentation method which automatically segments tumors from human brain MRI image volume. The presented model is based on the symmetry of human brain and level set method. Firstly, the midsagittal plane of an MRI volume is searched, the slices with potential tumor of the volume are checked out according to their symmetries, and an initial boundary of the tumor in the slice, in which the tumor is in the largest size, is determined meanwhile by watershed and morphological algorithms; Secondly, the level set method is applied to the initial boundary to drive the curve evolving and stopping to the appropriate tumor boundary; Lastly, the tumor boundary is projected one by one to its adjacent slices as initial boundaries through the volume for the whole tumor. The experiment results are compared with hand tracking of the expert and show relatively good accordance between both.

Deconstructing brain-derived neurotrophic factor actions in adult brain circuits to bridge an existing informational gap in neuro-cell biology.

PubMed

Bowling, Heather; Bhattacharya, Aditi; Klann, Eric; Chao, Moses V

2016-03-01

Brain-derived neurotrophic factor (BDNF) plays an important role in neurodevelopment, synaptic plasticity, learning and memory, and in preventing neurodegeneration. Despite decades of investigations into downstream signaling cascades and changes in cellular processes, the mechanisms of how BDNF reshapes circuits in vivo remain unclear. This informational gap partly arises from the fact that the bulk of studies into the molecular actions of BDNF have been performed in dissociated neuronal cultures, while the majority of studies on synaptic plasticity, learning and memory were performed in acute brain slices or in vivo. A recent study by Bowling-Bhattacharya et al., measured the proteomic changes in acute adult hippocampal slices following treatment and reported changes in proteins of neuronal and non-neuronal origin that may in concert modulate synaptic release and secretion in the slice. In this paper, we place these findings into the context of existing literature and discuss how they impact our understanding of how BDNF can reshape the brain.

Brevetoxin Depresses Synaptic Transmission in Guinea Pig Hippocampal Slices

DTIC Science & Technology

1993-01-01

Brevetoxin depresses synaptic transmission in guinea pig hippocampal slices. Brain Res Bull 31(1/2) 201-207, 1993.--Extracellular recordings were...obtained from area CA1 of guinea pig hippocampal slices. PbTx-3, a brevetoxin fraction isolated from the red tide dinoflagellate Ptychodiscus brevis, was

The detectability of brain metastases using contrast-enhanced spin-echo or gradient-echo images: a systematic review and meta-analysis.

PubMed

Suh, Chong Hyun; Jung, Seung Chai; Kim, Kyung Won; Pyo, Junhee

2016-09-01

This study aimed to compare the detectability of brain metastases using contrast-enhanced spin-echo (SE) and gradient-echo (GRE) T1-weighted images. The Ovid-MEDLINE and EMBASE databases were searched for studies on the detectability of brain metastases using contrast-enhanced SE or GRE images. The pooled proportions for the detectability of brain metastases were assessed using random-effects modeling. Heterogeneity among studies was determined using χ (2) statistics for the pooled estimates and the inconsistency index, I (2) . To overcome heterogeneity, subgroup analyses according to slice thickness and lesion size were performed. A total of eight eligible studies, which included a sample size of 252 patients and 1413 brain metastases, were included. The detectability of brain metastases using SE images (89.2 %) was higher than using GRE images (81.6 %; adjusted 84.0 %), but this difference was not statistically significant (p = 0.2385). In subgroup analysis of studies with 1-mm-thick slices and small metastases (<5 mm in diameter), 3-dimensional (3D) SE images demonstrated a higher detectability in comparison to 3D GRE images (93.7 % vs 73.1 % in 1-mm-thick slices; 89.5 % vs 59.4 % for small metastases) (p < 0.0001). Although both SE or GRE images are acceptable for detecting brain metastases, contrast-enhanced 3D SE images using 1-mm-thick slices are preferred for detecting brain metastases, especially small lesions (<5 mm in diameter).

Fear Conditioning Effects on Sensitivity to Drug Reward

DTIC Science & Technology

2009-06-01

stored at –70 C. Coronal sections (40 µm) were collected and alternate slides were Nissl stained to verify the anatomical localization of the nucleus...using an slicing/antibody/ staining procedures and the results of these studies are exhibited in the figures and table below. Figure Legend...streptavidin technique (ABC Staining System, Santa Cruz Biotechnology, Inc. Santa Cruz, CA) with metal-enhanced 3,3’diaminobenzidine as the chromagen

Brain Volume Estimation Enhancement by Morphological Image Processing Tools.

PubMed

Zeinali, R; Keshtkar, A; Zamani, A; Gharehaghaji, N

2017-12-01

Volume estimation of brain is important for many neurological applications. It is necessary in measuring brain growth and changes in brain in normal/abnormal patients. Thus, accurate brain volume measurement is very important. Magnetic resonance imaging (MRI) is the method of choice for volume quantification due to excellent levels of image resolution and between-tissue contrast. Stereology method is a good method for estimating volume but it requires to segment enough MRI slices and have a good resolution. In this study, it is desired to enhance stereology method for volume estimation of brain using less MRI slices with less resolution. In this study, a program for calculating volume using stereology method has been introduced. After morphologic method, dilation was applied and the stereology method enhanced. For the evaluation of this method, we used T1-wighted MR images from digital phantom in BrainWeb which had ground truth. The volume of 20 normal brain extracted from BrainWeb, was calculated. The volumes of white matter, gray matter and cerebrospinal fluid with given dimension were estimated correctly. Volume calculation from Stereology method in different cases was made. In three cases, Root Mean Square Error (RMSE) was measured. Case I with T=5, d=5, Case II with T=10, D=10 and Case III with T=20, d=20 (T=slice thickness, d=resolution as stereology parameters). By comparing these results of two methods, it is obvious that RMSE values for our proposed method are smaller than Stereology method. Using morphological operation, dilation allows to enhance the estimation volume method, Stereology. In the case with less MRI slices and less test points, this method works much better compared to Stereology method.

The use of maxillary sinus dimensions in gender determination: a thin-slice multidetector computed tomography assisted morphometric study.

PubMed

Ekizoglu, Oguzhan; Inci, Ercan; Hocaoglu, Elif; Sayin, Ibrahim; Kayhan, Fatma Tulin; Can, Ismail Ozgur

2014-05-01

Gender determination is an important step in identification. For gender determination, anthropometric evaluation is one of the main forensic evaluations. In the present study, morphometric analysis of maxillary sinuses was performed to determine gender. For morphometric analysis, coronal and axial paranasal sinus computed tomography (CT) scan with 1-mm slice thickness was used. For this study, 140 subjects (70 women and 70 men) were enrolled (age ranged between 18 and 63). The size of each subject's maxillary sinuses was measured in anteroposterior, transverse, cephalocaudal, and volume directions. In each measurement, the size of the maxillary sinus is significantly small in female gender (P < 0.001). When discrimination analysis was performed, the accuracy rate was detected as 80% for women and 74.3% for men with an overall rate of 77.15%. With the use of 1-mm slice thickness CT, morphometric analysis of maxillary sinuses will be helpful for gender determination.

Pyridostigmine-Induced Neurodegeneration: Role of Neuronal Apoptosis.

DTIC Science & Technology

1999-10-01

carbachol releases glutamate and glycine from dorsal cochlear nucleus brain slices (Chen et al, 1999). No other amino acids were released from brain...Sivasamy (1997) reported that the anticholinesterase, phosphamidon, caused apoptosis in spermatogenic line cells. Also, muscarinic agonists, carbachol and...1999) Glutamergic transmission of neuronal responses to carbachol in rat cochlear nucleus slices. Neurosci. 90: 2043-2049. Crews, F.T., Steck, J.C

Acetylcholinesterase inhibition reveals endogenous nicotinic modulation of glutamate inputs to CA1 stratum radiatum interneurons in hippocampal slices

PubMed Central

Alkondon, Manickavasagom; Albuquerque, Edson X.; Pereira, Edna F.R.

2013-01-01

The involvement of brain nicotinic acetylcholine receptors (nAChRs) in the neurotoxicological effects of soman, a potent acetylcholinesterase (AChE) inhibitor and a chemical warfare agent, is not clear. This is partly due to a poor understanding of the role of AChE in brain nAChR-mediated functions. To test the hypothesis that AChE inhibition builds sufficient acetylcholine (ACh) in the brain and facilitates nAChR-dependent glutamate transmission, we used whole-cell patch-clamp technique to record spontaneous glutamate excitatory postsynaptic currents (EPSCs) from CA1 stratum radiatum interneurons (SRI) in hippocampal slices. First, the frequency, amplitude and kinetics of EPSCs recorded from slices of control guinea pigs were compared to those recorded from slices of guinea pigs after a single injection of the irreversible AChE inhibitor soman (25.2 μg/kg, s.c.). Second, EPSCs were recorded from rat hippocampal slices before and after their superfusion with the reversible AChE inhibitor donepezil (100 nM). The frequency of EPSCs was significantly higher in slices taken from guinea pigs 24 h but not 7 days after the soman injection than in slices from control animals. In 52% of the rat hippocampal slices tested, bath application of donepezil increased the frequency of EPSCs. Further, exposure to donepezil increased both burst-like and large-amplitude EPSCs, and increased the proportion of short (20–100 ms) inter-event intervals. Donepezil’s effects were suppressed significantly in presence of 10 μM mecamylamine or 10 nM methyllycaconitine. These results support the concept that AChE inhibition is able to recruit nAChR-dependent glutamate transmission in the hippocampus and such a mechanism can contribute to the acute neurotoxicological actions of soman. PMID:23511125

Comparative analysis of 2 glenoid version measurement methods in variable axial slices on 3-dimensionally reconstructed computed tomography scans.

PubMed

Cunningham, Gregory; Freebody, John; Smith, Margaret M; Taha, Mohy E; Young, Allan A; Cass, Benjamin; Giuffre, Bruno

2018-05-16

Most glenoid version measurement methods have been validated on 3-dimensionally corrected axial computed tomography (CT) slices at the mid glenoid. Variability of the vault according to slice height and angulation has not yet been studied and is crucial for proper surgical implant positioning. The aim of this study was to analyze the variation of the glenoid vault compared with the Friedman angle according to different CT slice heights and angulations. The hypothesis was that the Friedman angle would show less variability. Sixty shoulder CT scans were retrieved from a hospital imaging database and were reconstructed in the plane of the scapula. Seven axial slices of different heights and coronal angulations were selected, and measurements were carried out by 3 observers. Mid-glenoid mean version was -8.0° (±4.9°; range, -19.6° to +7.0°) and -2.1° (±4.7°; range, -13.0° to +10.3°) using the vault method and Friedman angle, respectively. For both methods, decreasing slice height or angulation did not significantly alter version. Increasing slice height or angulation significantly increased anteversion for the vault method (P < .001). Both interobserver reliability and intraobserver reliability were significantly higher using the Friedman angle. Version at the mid and lower glenoid is similar using either method. The vault method shows less reliability and more variability according to slice height or angulation. Yet, as it significantly differs from the Friedman angle, it should still be used in situations where maximum bone purchase is sought with glenoid implants. For any other situation, the Friedman angle remains the method of choice. Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Differences in spike train variability in rat vasopressin and oxytocin neurons and their relationship to synaptic activity

PubMed Central

Li, Chunyan; Tripathi, Pradeep K; Armstrong, William E

2007-01-01

The firing pattern of magnocellular neurosecretory neurons is intimately related to hormone release, but the relative contribution of synaptic versus intrinsic factors to the temporal dispersion of spikes is unknown. In the present study, we examined the firing patterns of vasopressin (VP) and oxytocin (OT) supraoptic neurons in coronal slices from virgin female rats, with and without blockade of inhibitory and excitatory synaptic currents. Inhibitory postsynaptic currents (IPSCs) were twice as prevalent as their excitatory counterparts (EPSCs), and both were more prevalent in OT compared with VP neurons. Oxytocin neurons fired more slowly and irregularly than VP neurons near threshold. Blockade of Cl− currents (including tonic and synaptic currents) with picrotoxin reduced interspike interval (ISI) variability of continuously firing OT and VP neurons without altering input resistance or firing rate. Blockade of EPSCs did not affect firing pattern. Phasic bursting neurons (putative VP neurons) were inconsistently affected by broad synaptic blockade, suggesting that intrinsic factors may dominate the ISI distribution during this mode in the slice. Specific blockade of synaptic IPSCs with gabazine also reduced ISI variability, but only in OT neurons. In all cases, the effect of inhibitory blockade on firing pattern was independent of any consistent change in input resistance or firing rate. Since the great majority of IPSCs are randomly distributed, miniature events (mIPSCs) in the coronal slice, these findings imply that even mIPSCs can impart irregularity to the firing pattern of OT neurons in particular, and could be important in regulating spike patterning in vivo. For example, the increased firing variability that precedes bursting in OT neurons during lactation could be related to significant changes in synaptic activity. PMID:17332000

Effect of slice thickness on brain magnetic resonance image texture analysis

PubMed Central

2010-01-01

Background The accuracy of texture analysis in clinical evaluation of magnetic resonance images depends considerably on imaging arrangements and various image quality parameters. In this paper, we study the effect of slice thickness on brain tissue texture analysis using a statistical approach and classification of T1-weighted images of clinically confirmed multiple sclerosis patients. Methods We averaged the intensities of three consecutive 1-mm slices to simulate 3-mm slices. Two hundred sixty-four texture parameters were calculated for both the original and the averaged slices. Wilcoxon's signed ranks test was used to find differences between the regions of interest representing white matter and multiple sclerosis plaques. Linear and nonlinear discriminant analyses were applied with several separate training and test sets to determine the actual classification accuracy. Results Only moderate differences in distributions of the texture parameter value for 1-mm and simulated 3-mm-thick slices were found. Our study also showed that white matter areas are well separable from multiple sclerosis plaques even if the slice thickness differs between training and test sets. Conclusions Three-millimeter-thick magnetic resonance image slices acquired with a 1.5 T clinical magnetic resonance scanner seem to be sufficient for texture analysis of multiple sclerosis plaques and white matter tissue. PMID:20955567

Effect of metabolic alterations on the accumulation of technetium-99m-labeled d, l-HMPAO in slices of rat cerebral cortex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, C.S.; Tow, D.E.; Yu, C.C.

1994-03-01

It is widely recognized that the distribution of technetium-99m-labeled d,l-hexamethylpropylene amine oxime ({sup 99m}Tc-HMPAO) in the brain is determined by the regional blood flow. However, other factors may affect this process including the metabolism of the brain tissue. To examine this possibility we studied the effects of metabolic alterations on {sup 99m}Tc-HMPAO uptake in rat brain cortex slices, with concurrent measurement of oxygen consumption (QO{sub 2}). {sup 99m}Tc-HMPAO uptake was determined by incubating slices of rat cerebral cortex at 37{degrees}C in Krebs-Ringer phosphate glucose medium containing {sup 99m}Tc-HMPAO with and without test substances. Differential gradients for {sup 99m}Tc activity betweenmore » the tissue and the suspending medium (T/M ratio) were derived from the equation T/M[{sup 99m}Tc] = counts per gram of tissue/counts per milliliter of medium. The QO{sub 2} of the brain slices was measured using a biological oxygen monitor equipped with a polarographic oxygen probe. Inhibitors affecting oxidative phosphorylation caused parallel suppression of the T/M ratio and QO{sub 2}. Agents that uncouple oxidation from phosphorylation increased the QO{sub 2} and decreased the T/M ratio. Incubation of slices at 22{degrees}C depressed the T/M ratio and QO{sub 2}. The presence of inhibitors of oxidative phosphorylation in the incubation medium increased the release of {sup 99m}Tc activity from slices that had been prelabeled with {sup 99m}Tc-HMPAO. These findings suggest that the altered metabolic status of the brain tissue modulates the kinetics and net accumulation of {sup 99m}Tc-HMPAO at the cellular level by either depressing uptake, increasing back-diffusion, or both. 33 refs., 4 figs., 3 tabs.« less

Fractal analysis of MRI data for the characterization of patients with schizophrenia and bipolar disorder.

PubMed

Squarcina, Letizia; De Luca, Alberto; Bellani, Marcella; Brambilla, Paolo; Turkheimer, Federico E; Bertoldo, Alessandra

2015-02-21

Fractal geometry can be used to analyze shape and patterns in brain images. With this study we use fractals to analyze T1 data of patients affected by schizophrenia or bipolar disorder, with the aim of distinguishing between healthy and pathological brains using the complexity of brain structure, in particular of grey matter, as a marker of disease. 39 healthy volunteers, 25 subjects affected by schizophrenia and 11 patients affected by bipolar disorder underwent an MRI session. We evaluated fractal dimension of the brain cortex and its substructures, calculated with an algorithm based on the box-count algorithm. We modified this algorithm, with the aim of avoiding the segmentation processing step and using all the information stored in the image grey levels. Moreover, to increase sensitivity to local structural changes, we computed a value of fractal dimension for each slice of the brain or of the particular structure. To have reference values in comparing healthy subjects with patients, we built a template by averaging fractal dimension values of the healthy volunteers data. Standard deviation was evaluated and used to create a confidence interval. We also performed a slice by slice t-test to assess the difference at slice level between the three groups. Consistent average fractal dimension values were found across all the structures in healthy controls, while in the pathological groups we found consistent differences, indicating a change in brain and structures complexity induced by these disorders.

Fractal analysis of MRI data for the characterization of patients with schizophrenia and bipolar disorder

NASA Astrophysics Data System (ADS)

Squarcina, Letizia; De Luca, Alberto; Bellani, Marcella; Brambilla, Paolo; Turkheimer, Federico E.; Bertoldo, Alessandra

2015-02-01

Fractal geometry can be used to analyze shape and patterns in brain images. With this study we use fractals to analyze T1 data of patients affected by schizophrenia or bipolar disorder, with the aim of distinguishing between healthy and pathological brains using the complexity of brain structure, in particular of grey matter, as a marker of disease. 39 healthy volunteers, 25 subjects affected by schizophrenia and 11 patients affected by bipolar disorder underwent an MRI session. We evaluated fractal dimension of the brain cortex and its substructures, calculated with an algorithm based on the box-count algorithm. We modified this algorithm, with the aim of avoiding the segmentation processing step and using all the information stored in the image grey levels. Moreover, to increase sensitivity to local structural changes, we computed a value of fractal dimension for each slice of the brain or of the particular structure. To have reference values in comparing healthy subjects with patients, we built a template by averaging fractal dimension values of the healthy volunteers data. Standard deviation was evaluated and used to create a confidence interval. We also performed a slice by slice t-test to assess the difference at slice level between the three groups. Consistent average fractal dimension values were found across all the structures in healthy controls, while in the pathological groups we found consistent differences, indicating a change in brain and structures complexity induced by these disorders.

Transport mechanism of L-[14C]glutamate in cortical slices and synaptosomes of rabbits exposed to brain ischemia and reperfusion.

PubMed

Solyakov, L; Dobrota, D; Drany, O; Vachova, M; Machac, S; Mezesova, V; Bachurin, S; Lombardi, V

1995-01-01

Changes in the functioning of the glutamatergic system in rabbit brain were studied after partial brain ischemia and reperfusion. In vitro studies were conducted relating to the release of L-[14C]glutamate from cortical brain slices, L-[14C]glutamate uptake in synaptosomes, and 45Ca uptake in synaptosomes. It was found that basal release of L-[14C]glutamate from rabbit brain cortical slices after 30 min of partial ischemia and 1 d of reperfusion was essentially without change compared to the control values. After 3 d of reperfusion, there was an increase in basal release of L-[14C]glutamate from rabbit brain cortical slices. K+ stimulated release of L-[14C]glutamate in normal Krebs-Ringer medium was essentially the same in the control group and in the experimental group after 30 min of ischemia. The K+ stimulated release of L-[14C]glutamate independent of calcium was increased to 145% after 30 min of ischemia and 1 d of reperfusion. The decreased Km value at the glutamate transporter may have contributed to this difference. Kinetic parameters of the L-[14C]glutamate uptake (Km and Vmax) in synaptosomes from rabbit brain were significantly lower after 30 min of ischemia. The authors discovered that during the reperfusion period, Vmax was almost the same as in the control group. The activity of the Na+/Ca2+ exchanger in synaptosomes of rat brain was about 70% of the control values after 30 min of ischemia and 72 h of reperfusion. According to our results, increased L-[14C]glutamate release after 30 min of ischemia appears to be the result of higher intracellular calcium concentration and possibly also of a higher uptake of glutamate.

Imaging of Brain Slices with a Genetically Encoded Voltage Indicator.

PubMed

Quicke, Peter; Barnes, Samuel J; Knöpfel, Thomas

2017-01-01

Functional fluorescence microscopy of brain slices using voltage sensitive fluorescent proteins (VSFPs) allows large scale electrophysiological monitoring of neuronal excitation and inhibition. We describe the equipment and techniques needed to successfully record functional responses optical voltage signals from cells expressing a voltage indicator such as VSFP Butterfly 1.2. We also discuss the advantages of voltage imaging and the challenges it presents.

Co-registration of In-Vivo Human MRI Brain Images to Postmortem Histological Microscopic Images

PubMed Central

Singh, M.; Rajagopalan, A.; Kim, T.-S.; Hwang, D.; Chui, H.; Zhang, X.-L.; Lee, A.-Y.; Zarow, C.

2009-01-01

Certain features such as small vascular lesions seen in human MRI are detected reliably only in postmortem histological samples by microscopic imaging. Co-registration of these microscopically detected features to their corresponding locations in the in-vivo images would be of great benefit to understanding the MRI signatures of specific diseases. Using non-linear Polynomial transformation, we report a method to co-register in-vivo MRIs to microscopic images of histological samples drawn off the postmortem brain. The approach utilizes digital photographs of postmortem slices as an intermediate reference to co-register the MRIs to microscopy. The overall procedure is challenging due to gross structural deformations in the postmortem brain during extraction and subsequent distortions in the histological preparations. Hemispheres of the brain were co-registered separately to mitigate these effects. Approaches relying on matching single-slices, multiple-slices and entire volumes in conjunction with different similarity measures suggested that using four slices at a time in combination with two sequential measures, Pearson correlation coefficient followed by mutual information, produced the best MRI-postmortem co-registration according to a voxel mismatch count. The accuracy of the overall registration was evaluated by measuring the 3D Euclidean distance between the locations of microscopically identified lesions on postmortem slices and their MRI-postmortem co-registered locations. The results show a mean 3D displacement of 5.1 ± 2.0 mm between the in-vivo MRI and microscopically determined locations for 21 vascular lesions in 11 subjects. PMID:19169415

Central Mechanisms and Treatment of Blast-Induced Auditory and Vestibular Injuries

DTIC Science & Technology

2018-01-01

Standards and control samples were run simultaneously for validation.  Western blotting: Twenty micrograms of the protein extracts were fractionated by...removed after being administered with isoflurane and slice (400 µm) was cut in coronal section using a vibrating blade microtome (Leica VT1000S, Leica...P21958 (ThermoFisher scientific). The eluate was run to a SDS-PAGE gel and was silver stained using a complete kit (24600, ThermoFisher Scientific

Exercise training reinstates cortico-cortical sensorimotor functional connectivity following striatal lesioning: Development and application of a subregional-level analytic toolbox for perfusion autoradiographs of the rat brain

NASA Astrophysics Data System (ADS)

Peng, Yu-Hao; Heintz, Ryan; Wang, Zhuo; Guo, Yumei; Myers, Kalisa; Scremin, Oscar; Maarek, Jean-Michel; Holschneider, Daniel

2014-12-01

Current rodent connectome projects are revealing brain structural connectivity with unprecedented resolution and completeness. How subregional structural connectivity relates to subregional functional interactions is an emerging research topic. We describe a method for standardized, mesoscopic-level data sampling from autoradiographic coronal sections of the rat brain, and for correlation-based analysis and intuitive display of cortico-cortical functional connectivity (FC) on a flattened cortical map. A graphic user interface “Cx-2D” allows for the display of significant correlations of individual regions-of-interest, as well as graph theoretical metrics across the cortex. Cx-2D was tested on an autoradiographic data set of cerebral blood flow (CBF) of rats that had undergone bilateral striatal lesions, followed by 4 weeks of aerobic exercise training or no exercise. Effects of lesioning and exercise on cortico-cortical FC were examined during a locomotor challenge in this rat model of Parkinsonism. Subregional FC analysis revealed a rich functional reorganization of the brain in response to lesioning and exercise that was not apparent in a standard analysis focused on CBF of isolated brain regions. Lesioned rats showed diminished degree centrality of lateral primary motor cortex, as well as neighboring somatosensory cortex--changes that were substantially reversed in lesioned rats following exercise training. Seed analysis revealed that exercise increased positive correlations in motor and somatosensory cortex, with little effect in non-sensorimotor regions such as visual, auditory, and piriform cortex. The current analysis revealed that exercise partially reinstated sensorimotor FC lost following dopaminergic deafferentation. Cx-2D allows for standardized data sampling from images of brain slices, as well as analysis and display of cortico-cortical FC in the rat cerebral cortex with potential applications in a variety of autoradiographic and histologic studies.

Semi-automatic brain tumor segmentation by constrained MRFs using structural trajectories.

PubMed

Zhao, Liang; Wu, Wei; Corso, Jason J

2013-01-01

Quantifying volume and growth of a brain tumor is a primary prognostic measure and hence has received much attention in the medical imaging community. Most methods have sought a fully automatic segmentation, but the variability in shape and appearance of brain tumor has limited their success and further adoption in the clinic. In reaction, we present a semi-automatic brain tumor segmentation framework for multi-channel magnetic resonance (MR) images. This framework does not require prior model construction and only requires manual labels on one automatically selected slice. All other slices are labeled by an iterative multi-label Markov random field optimization with hard constraints. Structural trajectories-the medical image analog to optical flow and 3D image over-segmentation are used to capture pixel correspondences between consecutive slices for pixel labeling. We show robustness and effectiveness through an evaluation on the 2012 MICCAI BRATS Challenge Dataset; our results indicate superior performance to baselines and demonstrate the utility of the constrained MRF formulation.

Optimized heterologous transfection of viable adult organotypic brain slices using an enhanced gene gun

PubMed Central

2013-01-01

Background Organotypic brain slices (OTBS) are an excellent experimental compromise between the facility of working with cell cultures and the biological relevance of using animal models where anatomical, morphological, and cellular function of specific brain regions can be maintained. The biological characteristics of OTBS can subsequently be examined under well-defined conditions. They do, however, have a number of limitations; most brain slices are derived from neonatal animals, as it is difficult to properly prepare and maintain adult OTBS. There are ample problems with tissue integrity as OTBS are delicate and frequently become damaged during the preparative stages. Notwithstanding these obstacles, the introduced exogenous proteins into both neuronal cells, and cells imbedded within tissues, have been consistently difficult to achieve. Results Following the ex vivo extraction of adult mouse brains, mounted inside a medium-agarose matrix, we have exploited a precise slicing procedure using a custom built vibroslicer. To transfect these slices we used an improved biolistic transfection method using a custom made low-pressure barrel and novel DNA-coated nanoparticles (40 nm), which are drastically smaller than traditional microparticles. These nanoparticles also minimize tissue damage as seen by a significant reduction in lactate dehydrogenase activity as well as propidium iodide (PI) and dUTP labelling compared to larger traditional gold particles used on these OTBS. Furthermore, following EYFP exogene delivery by gene gun, the 40 nm treated OTBS displayed a significantly larger number of viable NeuN and EYFP positive cells. These OTBS expressed the exogenous proteins for many weeks. Conclusions Our described methodology of producing OTBS, which results in better reproducibility with less tissue damage, permits the exploitation of mature fully formed adult brains for advanced neurobiological studies. The novel 40 nm particles are ideal for the viable biolistic transfection of OTBS by reducing tissue stress while maintaining long term exogene expression. PMID:24354851

Time efficient whole-brain coverage with MR Fingerprinting using slice-interleaved echo-planar-imaging.

PubMed

Rieger, Benedikt; Akçakaya, Mehmet; Pariente, José C; Llufriu, Sara; Martinez-Heras, Eloy; Weingärtner, Sebastian; Schad, Lothar R

2018-04-27

Magnetic resonance fingerprinting (MRF) is a promising method for fast simultaneous quantification of multiple tissue parameters. The objective of this study is to improve the coverage of MRF based on echo-planar imaging (MRF-EPI) by using a slice-interleaved acquisition scheme. For this, the MRF-EPI is modified to acquire several slices in a randomized interleaved manner, increasing the effective repetition time of the spoiled gradient echo readout acquisition in each slice. Per-slice matching of the signal-trace to a precomputed dictionary allows the generation of T 1 and T 2 * maps with integrated B 1 + correction. Subsequent compensation for the coil sensitivity profile and normalization to the cerebrospinal fluid additionally allows for quantitative proton density (PD) mapping. Numerical simulations are performed to optimize the number of interleaved slices. Quantification accuracy is validated in phantom scans and feasibility is demonstrated in-vivo. Numerical simulations suggest the acquisition of four slices as a trade-off between quantification precision and scan-time. Phantom results indicate good agreement with reference measurements (Difference T 1 : -2.4 ± 1.1%, T 2 *: -0.5 ± 2.5%, PD: -0.5 ± 7.2%). In-vivo whole-brain coverage of T 1 , T 2 * and PD with 32 slices was acquired within 3:36 minutes, resulting in parameter maps of high visual quality and comparable performance with single-slice MRF-EPI at 4-fold scan-time reduction.

Direct Comparison of Respiration-Correlated Four-Dimensional Magnetic Resonance Imaging Reconstructed Using Concurrent Internal Navigator and External Bellows.

PubMed

Li, Guang; Wei, Jie; Olek, Devin; Kadbi, Mo; Tyagi, Neelam; Zakian, Kristen; Mechalakos, James; Deasy, Joseph O; Hunt, Margie

2017-03-01

To compare the image quality of amplitude-binned 4-dimensional magnetic resonance imaging (4DMRI) reconstructed using 2 concurrent respiratory (navigator and bellows) waveforms. A prospective, respiratory-correlated 4DMRI scanning program was used to acquire T2-weighted single-breath 4DMRI images with internal navigator and external bellows. After a 10-second training waveform of a surrogate signal, 2-dimensional MRI acquisition was triggered at a level (bin) and anatomic location (slice) until the bin-slice table was completed for 4DMRI reconstruction. The bellows signal was always collected, even when the navigator trigger was used, to retrospectively reconstruct a bellows-rebinned 4DMRI. Ten volunteers participated in this institutional review board-approved 4DMRI study. Four scans were acquired for each subject, including coronal and sagittal scans triggered by either navigator or bellows, and 6 4DMRI images (navigator-triggered, bellows-rebinned, and bellows-triggered) were reconstructed. The simultaneously acquired waveforms and resulting 4DMRI quality were compared using signal correlation, bin/phase shift, and binning motion artifacts. The consecutive bellows-triggered 4DMRI scan was used for indirect comparison. Correlation coefficients between the navigator and bellows signals were found to be patient-specific and inhalation-/exhalation-dependent, ranging from 0.1 to 0.9 because of breathing irregularities (>50% scans) and commonly observed bin/phase shifts (-1.1 ± 0.6 bin) in both 1-dimensional waveforms and diaphragm motion extracted from 4D images. Navigator-triggered 4DMRI contained many fewer binning motion artifacts at the diaphragm than did the bellows-rebinned and bellows-triggered 4DMRI scans. Coronal scans were faster than sagittal scans because of the fewer slices and higher achievable acceleration factors. Navigator-triggered 4DMRI contains substantially fewer binning motion artifacts than bellows-rebinned and bellows-triggered 4DMRI, primarily owing to the deviation of the external from the internal surrogate. The present study compared 2 concurrent surrogates during the same 4DMRI scan and their resulting 4DMRI quality. The navigator-triggered 4DMRI scanning protocol should be preferred to the bellows-based, especially for coronal scans, for clinical respiratory motion simulation. Copyright © 2016 Elsevier Inc. All rights reserved.

The mouse cerebellar cortex in organotypic slice cultures: an in vitro model to analyze the consequences of mutations and pathologies on neuronal survival, development, and function.

PubMed

Lonchamp, Etienne; Dupont, Jean-Luc; Beekenkamp, Huguette; Poulain, Bernard; Bossu, Jean-Louis

2006-01-01

Thin acute slices and dissociated cell cultures taken from different parts of the brain have been widely used to examine the function of the nervous system, neuron-specific interactions, and neuronal development (specifically, neurobiology, neuropharmacology, and neurotoxicology studies). Here, we focus on an alternative in vitro model: brain-slice cultures in roller tubes, initially introduced by Beat Gähwiler for studies with rats, that we have recently adapted for studies of mouse cerebellum. Cultured cerebellar slices afford many of the advantages of dissociated cultures of neurons and thin acute slices. Organotypic slice cultures were established from newborn or 10-15-day-old mice. After 3-4 weeks in culture, the slices flattened to form a cell monolayer. The main types of cerebellar neurons could be identified with immunostaining techniques, while their electrophysiological properties could be easily characterized with the patch-clamp recording technique. When slices were taken from newborn mice and cultured for 3 weeks, aspects of the cerebellar development were displayed. A functional neuronal network was established despite the absence of mossy and climbing fibers, which are the two excitatory afferent projections to the cerebellum. When slices were made from 10-15-day-old mice, which are at a developmental stage when cerebellum organization is almost established, the structure and neuronal pathways were intact after 3-4 weeks in culture. These unique characteristics make organotypic slice cultures of mouse cerebellar cortex a valuable model for analyzing the consequences of gene mutations that profoundly alter neuronal function and compromise postnatal survival.

A brain slice bath for physiology and compound microscopy, with dual-sided perifusion.

PubMed

Heyward, P M

2010-12-01

Contemporary in vitro brain slice studies can employ compound microscopes to identify individual neurons or their processes for physiological recording or imaging. This requires that the bath used to maintain the tissue fits within the working distances of a water-dipping objective and microscope condenser. A common means of achieving this is to maintain thin tissue slices on the glass floor of a recording bath, exposing only one surface of the tissue to oxygenated bathing medium. Emerging evidence suggests that physiology can be compromised by this approach. Flowing medium past both sides of submerged brain slices is optimal, but recording baths utilizing this principle are not readily available for use on compound microscopes. This paper describes a tissue bath designed specifically for microscopy and physiological recording, in which temperature-controlled medium flows past both sides of the slices. A particular feature of this design is the use of concentric mesh rings to support and transport the live tissue without mechanical disturbance. The design is also easily adapted for use with thin acute slices, cultured slices, and acutely dispersed or cultured cells maintained either on cover slips or placed directly on the floor of the bath. The low profile of the bath provides a low angle of approach for electrodes, and allows use of standard condensers, nosepieces and water-dipping objective lenses. If visualization of individual neurons is not required, the bath can be mounted on a simple stand and used with a dissecting microscope. Heating is integral to the bath, and any temperature controller capable of driving a resistive load can be used. The bath is robust, readily constructed and requires minimal maintenance. Full construction and operation details are given. © 2010 The Author Journal of Microscopy © 2010 The Royal Microscopical Society.

Thin isotropic FLAIR MR images at 1.5T increase the yield of focal cortical dysplasia transmantle sign detection in frontal lobe epilepsy.

PubMed

Kokkinos, Vasileios; Kallifatidis, Alexandros; Kapsalaki, Eftychia Z; Papanikolaou, Nikolaos; Garganis, Kyriakos

2017-05-01

The transmantle sign is a distinctive imaging marker of focal cortical dysplasia (FCD) type II in frontal lobe epilepsy (FLE), which is revealed predominantly by fluid-attenuation inversion recovery (FLAIR) sequences. Although the transmantle sign detection yield is high by routine imaging protocols for epilepsy at 3T, most centers around the world have access to 1.5T MR technology and FLE patients often receive negative imaging reports. This study investigates the optimization of transmantle detection yield at 1.5T by introducing a 3D thin-slice isotropic FLAIR sequence in the epilepsy imaging protocol. Twenty FLE patients underwent diagnostic imaging for epilepsy with typical 2D thick-slice (3.0mm) coronal FLAIR sequences and a 3D thin-slice (1.0mm) isotropic FLAIR sequences at 1.5T, and transmantle sign detection yields and thickness measurements were derived. The 2D thick-slice FLAIR detected a transmantle sign in seven (35.0%) patients. The 3D isotropic thin-slice FLAIR detected a transmantle sign in eleven (55.0%) patients, thereby increasing the transmantle sign detection yield by 57.4%. The mean transmantle sign thickness by thick images was 12.3mm, by thin images was 8.9mm, and in the patients undetected by thick FLAIR was 3.5mm. This study showed that the extratemporal transmantle sign in FLE patients can be thin enough to be missed by thick-slice FLAIR sequences at 1.5T. By introducing 3D thin-slice isotropic FLAIR, false-negative reports can be reduced without reference for higher MR field structural scanning or other modalities, and more FLE patients can benefit from epilepsy surgery candidacy. Copyright © 2017 Elsevier B.V. All rights reserved.

SU-E-J-157: Improving the Quality of T2-Weighted 4D Magnetic Resonance Imaging for Clinical Evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, D; Mutic, S; Hu, Y

2014-06-01

Purpose: To develop an imaging technique that enables us to acquire T2- weighted 4D Magnetic Resonance Imaging (4DMRI) with sufficient spatial coverage, temporal resolution and spatial resolution for clinical evaluation. Methods: T2-weighed 4DMRI images were acquired from a healthy volunteer using a respiratory amplitude triggered T2-weighted Turbo Spin Echo sequence. 10 respiratory states were used to equally sample the respiratory range based on amplitude (0%, 20%i, 40%i, 60%i, 80%i, 100%, 80%e, 60%e, 40%e and 20%e). To avoid frequent scanning halts, a methodology was devised that split 10 respiratory states into two packages in an interleaved manner and packages were acquiredmore » separately. Sixty 3mm sagittal slices at 1.5mm in-plane spatial resolution were acquired to offer good spatial coverage and reasonable spatial resolution. The in-plane field of view was 375mm × 260mm with nominal scan time of 3 minutes 42 seconds. Acquired 2D images at the same respiratory state were combined to form the 3D image set corresponding to that respiratory state and reconstructed in the coronal view to evaluate whether all slices were at the same respiratory state. 3D image sets of 10 respiratory states represented a complete 4D MRI image set. Results: T2-weighted 4DMRI image were acquired in 10 minutes which was within clinical acceptable range. Qualitatively, the acquired MRI images had good image quality for delineation purposes. There were no abrupt position changes in reconstructed coronal images which confirmed that all sagittal slices were in the same respiratory state. Conclusion: We demonstrated it was feasible to acquire T2-weighted 4DMRI image set within a practical amount of time (10 minutes) that had good temporal resolution (10 respiratory states), spatial resolution (1.5mm × 1.5mm × 3.0mm) and spatial coverage (60 slices) for future clinical evaluation.« less

A comprehensive visual rating scale of brain magnetic resonance imaging: application in elderly subjects with Alzheimer's disease, mild cognitive impairment, and normal cognition.

PubMed

Jang, Jae-Won; Park, So Young; Park, Young Ho; Baek, Min Jae; Lim, Jae-Sung; Youn, Young Chul; Kim, SangYun

2015-01-01

Brain magnetic resonance imaging (MRI) shows cerebral structural changes. However, a unified comprehensive visual rating scale (CVRS) has seldom been studied. Thus, we combined brain atrophy and small vessel disease scales and used an MRI template as a CVRS. The aims of this study were to design a simple and reliable CVRS, validate it by investigating cerebral structural changes in clinical groups, and made comparison to the volumetric measurements. Elderly subjects (n = 260) with normal cognition (NC, n = 65), mild cognitive impairment (MCI, n = 101), or Alzheimer's disease (AD, n = 94) were evaluated with brain MRI according to the CVRS of brain atrophy and small vessel disease. Validation of the CVRS with structural changes, neuropsychological tests, and volumetric analyses was performed. The CVRS revealed a high intra-rater and inter-rater agreement and it reflected the structural changes of subjects with NC, MCI, and AD better than volumetric measures (CVRS-coronal: F = 13.5, p < 0.001; CVRS-axial: F = 19.9, p < 0.001). The area under the receiver operation curve (aROC) of the CVRS showed higher accuracy than volumetric analyses. (NC versus MCI aROC: CVRS-coronal, 0.777; CVRS-axial, 0.773; MCI versus AD aROC: CVRS-coronal, 0.680; CVRS-axial, 0.681). The CVRS can be used clinically to conveniently measure structural changes of brain. It reflected cerebral structural changes of clinical groups and correlated with the age better than volumetric measures.

Gender and age effects in structural brain asymmetry as measured by MRI texture analysis.

PubMed

Kovalev, Vassili A; Kruggel, Frithjof; von Cramon, D Yves

2003-07-01

Effects of gender and age on structural brain asymmetry were studied by 3D texture analysis in 380 adults. Asymmetry is detected by comparing the complex 3D gray-scale image patterns in the left and right cerebral hemispheres as revealed by anatomical T1-weighted MRI datasets. The Talairach and Tournoux parcellation system was applied to study the asymmetry on five levels: the whole cerebrum, nine coronal sections, 12 axial sections, boxes resulting from both coronal and axial subdivisions, and by a sliding spherical window of 9 mm diameter. The analysis revealed that the brain asymmetry increases in the anterior-posterior direction starting from the central region onward. Male brains were found to be more asymmetric than female. This gender-related effect is noticeable in all brain areas but is most significant in the superior temporal gyrus, Heschl's gyrus, the adjacent white matter regions in the temporal stem and the knee of the optic radiation, the thalamus, and the posterior cingulate. The brain asymmetry increases significantly with age in the inferior frontal gyrus, anterior insula, anterior cingulate, parahippocampal gyrus, retrosplenial cortex, coronal radiata, and knee region of the internal capsule. Asymmetry decreases with age in the optic radiation, precentral gyrus, and angular gyrus. The texture-based method reported here is based on extended multisort cooccurrence matrices that employ intensity, gradient, and anisotropy features in a uniform way. It is sensitive, simple to reproduce, robust, and unbiased in the sense that segmentation of brain compartments and spatial transformations are not necessary. Thus, it should be considered as another tool for digital morphometry in neuroscience.

A rapid approach to high-resolution fluorescence imaging in semi-thick brain slices.

PubMed

Selever, Jennifer; Kong, Jian-Qiang; Arenkiel, Benjamin R

2011-07-26

A fundamental goal to both basic and clinical neuroscience is to better understand the identities, molecular makeup, and patterns of connectivity that are characteristic to neurons in both normal and diseased brain. Towards this, a great deal of effort has been placed on building high-resolution neuroanatomical maps(1-3). With the expansion of molecular genetics and advances in light microscopy has come the ability to query not only neuronal morphologies, but also the molecular and cellular makeup of individual neurons and their associated networks(4). Major advances in the ability to mark and manipulate neurons through transgenic and gene targeting technologies in the rodent now allow investigators to 'program' neuronal subsets at will(5-6). Arguably, one of the most influential contributions to contemporary neuroscience has been the discovery and cloning of genes encoding fluorescent proteins (FPs) in marine invertebrates(7-8), alongside their subsequent engineering to yield an ever-expanding toolbox of vital reporters(9). Exploiting cell type-specific promoter activity to drive targeted FP expression in discrete neuronal populations now affords neuroanatomical investigation with genetic precision. Engineering FP expression in neurons has vastly improved our understanding of brain structure and function. However, imaging individual neurons and their associated networks in deep brain tissues, or in three dimensions, has remained a challenge. Due to high lipid content, nervous tissue is rather opaque and exhibits auto fluorescence. These inherent biophysical properties make it difficult to visualize and image fluorescently labelled neurons at high resolution using standard epifluorescent or confocal microscopy beyond depths of tens of microns. To circumvent this challenge investigators often employ serial thin-section imaging and reconstruction methods(10), or 2-photon laser scanning microscopy(11). Current drawbacks to these approaches are the associated labor-intensive tissue preparation, or cost-prohibitive instrumentation respectively. Here, we present a relatively rapid and simple method to visualize fluorescently labelled cells in fixed semi-thick mouse brain slices by optical clearing and imaging. In the attached protocol we describe the methods of: 1) fixing brain tissue in situ via intracardial perfusion, 2) dissection and removal of whole brain, 3) stationary brain embedding in agarose, 4) precision semi-thick slice preparation using new vibratome instrumentation, 5) clearing brain tissue through a glycerol gradient, and 6) mounting on glass slides for light microscopy and z-stack reconstruction (Figure 1). For preparing brain slices we implemented a relatively new piece of instrumentation called the 'Compresstome' VF-200 (http://www.precisionary.com/products_vf200.html). This instrument is a semi-automated microtome equipped with a motorized advance and blade vibration system with features similar in function to other vibratomes. Unlike other vibratomes, the tissue to be sliced is mounted in an agarose plug within a stainless steel cylinder. The tissue is extruded at desired thicknesses from the cylinder, and cut by the forward advancing vibrating blade. The agarose plug/cylinder system allows for reproducible tissue mounting, alignment, and precision cutting. In our hands, the 'Compresstome' yields high quality tissue slices for electrophysiology, immunohistochemistry, and direct fixed-tissue mounting and imaging. Combined with optical clearing, here we demonstrate the preparation of semi-thick fixed brain slices for high-resolution fluorescent imaging.

Brain Slice Staining and Preparation for Three-Dimensional Super-Resolution Microscopy

PubMed Central

German, Christopher L.; Gudheti, Manasa V.; Fleckenstein, Annette E.; Jorgensen, Erik M.

2018-01-01

Localization microscopy techniques – such as photoactivation localization microscopy (PALM), fluorescent PALM (FPALM), ground state depletion (GSD), and stochastic optical reconstruction microscopy (STORM) – provide the highest precision for single molecule localization currently available. However, localization microscopy has been largely limited to cell cultures due to the difficulties that arise in imaging thicker tissue sections. Sample fixation and antibody staining, background fluorescence, fluorophore photoinstability, light scattering in thick sections, and sample movement create significant challenges for imaging intact tissue. We have developed a sample preparation and image acquisition protocol to address these challenges in rat brain slices. The sample preparation combined multiple fixation steps, saponin permeabilization, and tissue clarification. Together, these preserve intracellular structures, promote antibody penetration, reduce background fluorescence and light scattering, and allow acquisition of images deep in a 30 μm thick slice. Image acquisition challenges were resolved by overlaying samples with a permeable agarose pad and custom-built stainless steel imaging adapter, and sealing the imaging chamber. This approach kept slices flat, immobile, bathed in imaging buffer, and prevented buffer oxidation during imaging. Using this protocol, we consistently obtained single molecule localizations of synaptic vesicle and active zone proteins in three-dimensions within individual synaptic terminals of the striatum in rat brain slices. These techniques may be easily adapted to the preparation and imaging of other tissues, substantially broadening the application of super-resolution imaging. PMID:28924666

Hexose transport by brain slices: further studies on energy dependence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kyle-Lillegard, J.; Gold, B.I.

1983-04-01

We studied the uptake of (/sup 3/H)2-deoxyglucose ((/sup 3/H)2DG) by slices of rat cerebral cortex in vitro as a model of glucose transport by brain. Slices were incubated with (/sup 3/H)2DG, or with L-(/sup 3/H)glucose as a marker for diffusion; the difference between (/sup 3/H)2DG uptake and L-(/sup 3/H)glucose uptake was defined as net (/sup 3/H)2DG transport. Net (/sup 3/H)2DG transport was a function of incubation temperature, with an estimated temperature coefficient of 1.87 from 15 degrees C to 25 degrees C. The net uptake of (/sup 3/H)2DG was not inhibited by phlorizin or phloretin in concentrations well above themore » reported Ki of these inhibitors for hexose uptake in other systems. To examine the hypothesis that (/sup 3/H)2DG transport by brain slices is dependent on mitochondrial energy, we studied net (/sup 3/H)2DG uptake by slices which had been preincubated in media designed to alter intracellular ATP stores. The transport process was very sensitive to inhibition by DNP, but the correlation between (/sup 3/H)2DG transport and ATP levels was unclear. In contrast to our published hypothesis that the transport process required mitochondrial energy, these data indicate that dependence on energy is not absolute.« less

The in vitro isolated whole guinea pig brain as a model to study epileptiform activity patterns.

PubMed

de Curtis, Marco; Librizzi, Laura; Uva, Laura

2016-02-15

Research on ictogenesis is based on the study of activity between seizures and during seizures in animal models of epilepsy (chronic condition) or in in vitro slices obtained from naïve non-epileptic brains after treatment with pro-convulsive drugs, manipulations of the extracellular medium and specific stimulation protocols. The in vitro isolated guinea pig brain retains the functional connectivity between brain structures and maintains interactions between neuronal, glial and vascular compartments. It is a close-to-in vivo preparation that offers experimental advantages not achieved with the use of other experimental models. Neurophysiological and imaging techniques can be utilized in this preparation to study brain activity during and between seizures induced by pharmacological or functional manipulations. Cellular and network determinants of interictal and ictal discharges that reproduce abnormal patterns observed in human focal epilepsies and the associated changes in extracellular ion and blood-brain permeability can be identified and analyzed in the isolated guinea pig brain. Ictal and interictal patterns recorded in in vitro slices may show substantial differences from seizure activity recorded in vivo due to slicing procedure itself. The isolated guinea pig brain maintained in vitro by arterial perfusion combines the typical facilitated access of in vitro preparations, that are difficult to approach during in vivo experiments, with the preservation of larger neuronal networks. The in vitro whole isolated guinea pig brain preparation offers an unique experimental model to study systemic and neurovascular changes during ictogenesis. Published by Elsevier B.V.

Location of radiosensitive organs inside pediatric anthropomorphic phantoms: Data required for dosimetry.

PubMed

Inkoom, Stephen; Raissaki, Maria; Perisinakis, Kostas; Maris, Thomas G; Damilakis, John

2015-12-01

The aim of this study was to determine the location of radiosensitive organs in the interior of four pediatric anthropomorphic phantoms for dosimetric purposes. Four pediatric anthropomorphic phantoms representing the average individual as newborn, 1-year-old, 5-year-old and 10-year-old child underwent head, thorax and abdomen CT scans. CT and MRI scans of all children aged 0-16 years performed during a 5-year-period in our hospital were reviewed, and 503 were found to be eligible for normal anatomy. Anterior-posterior and lateral dimensions of twelve of the above children closely matched that of the phantoms' head, thoracic and abdominal region in each four phantoms. The mid-sagittal and mid-coronal planes were drawn on selected matching axial images of patients and phantoms. Multiple points outlining large radiosensitive organs in patient images were identified at each slice level and their orthogonal distances from the mid-sagittal and mid-coronal planes were measured. In small organs, the coordinates of organs' centers were similarly determined. The outlines and centers of all radiosensitive organs were reproduced using the coordinates of each organ on corresponding phantoms' transverse images. The locations of the following radiosensitive organs in the interior of the four phantoms was determined: brain, eye lenses, salivary glands, thyroid, lungs, heart, thymus, esophagus, breasts, adrenals, liver, spleen, kidneys, stomach, gallbladder, small bowel, pancreas, colon, ovaries, bladder, prostate, uterus and rectum. The production of charts of radiosensitive organs inside pediatric anthropomorphic phantoms was feasible and may provide users reliable data for positioning of dosimeters during direct organ dose measurements. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

A Linear Temporal Increase in Thrombin Activity and Loss of Its Receptor in Mouse Brain following Ischemic Stroke.

PubMed

Bushi, Doron; Stein, Efrat Shavit; Golderman, Valery; Feingold, Ekaterina; Gera, Orna; Chapman, Joab; Tanne, David

2017-01-01

Brain thrombin activity is increased following acute ischemic stroke and may play a pathogenic role through the protease-activated receptor 1 (PAR1). In order to better assess these factors, we obtained a novel detailed temporal and spatial profile of thrombin activity in a mouse model of permanent middle cerebral artery occlusion (pMCAo). Thrombin activity was measured by fluorescence spectroscopy on coronal slices taken from the ipsilateral and contralateral hemispheres 2, 5, and 24 h following pMCAo ( n  = 5, 6, 5 mice, respectively). Its spatial distribution was determined by punch samples taken from the ischemic core and penumbra and further confirmed using an enzyme histochemistry technique ( n  = 4). Levels of PAR1 were determined using western blot. Two hours following pMCAo, thrombin activity in the stroke core was already significantly higher than the contralateral area (11 ± 5 vs. 2 ± 1 mU/ml). At 5 and 24 h, thrombin activity continued to rise linearly ( r  = 0.998, p  = 0.001) and to expand in the ischemic hemisphere beyond the ischemic core reaching deleterious levels of 271 ± 117 and 123 ± 14 mU/ml (mean ± SEM) in the basal ganglia and ischemic cortex, respectively. The peak elevation of thrombin activity in the ischemic core that was confirmed by fluorescence histochemistry was in good correlation with the infarcts areas. PAR1 levels in the ischemic core decreased as stroke progressed and thrombin activity increased. In conclusion, there is a time- and space-related increase in brain thrombin activity in acute ischemic stroke that is closely related to the progression of brain damage. These results may be useful in the development of therapeutic strategies for ischemic stroke that involve the thrombin-PAR1 pathway in order to prevent secondary thrombin related brain damage.

Preparation of organotypic brain slice cultures for the study of Alzheimer’s disease

PubMed Central

Croft, Cara L.; Noble, Wendy

2018-01-01

Alzheimer's disease, the most common cause of dementia, is a progressive neurodegenerative disorder characterised by amyloid-beta deposits in extracellular plaques, intracellular neurofibrillary tangles of aggregated tau, synaptic dysfunction and neuronal death. There are no cures for AD and current medications only alleviate some disease symptoms. Transgenic rodent models to study Alzheimer’s mimic features of human disease such as age-dependent accumulation of abnormal beta-amyloid and tau, synaptic dysfunction, cognitive deficits and neurodegeneration. These models have proven vital for improving our understanding of the molecular mechanisms underlying AD and for identifying promising therapeutic approaches. However, modelling neurodegenerative disease in animals commonly involves aging animals until they develop harmful phenotypes, often coupled with invasive procedures. In vivo studies are also resource, labour, time and cost intensive. We have developed a novel organotypic brain slice culture model to study Alzheimer’ disease which brings the potential of substantially reducing the number of rodents used in dementia research from an estimated 20,000 per year. We obtain 36 brain slices from each mouse pup, considerably reducing the numbers of animals required to investigate multiple stages of disease. This tractable model also allows the opportunity to modulate multiple pathways in tissues from a single animal. We believe that this model will most benefit dementia researchers in the academic and drug discovery sectors. We validated the slice culture model against aged mice, showing that the molecular phenotype closely mimics that displayed in vivo, albeit in an accelerated timescale. We showed beneficial outcomes following treatment of slices with agents previously shown to have therapeutic effects in vivo, and we also identified new mechanisms of action of other compounds. Thus, organotypic brain slice cultures from transgenic mouse models expressing Alzheimer’s disease-related genes may provide a valid and sensitive replacement for in vivo studies that do not involve behavioural analysis. PMID:29904599

Physiological Effects of Enriched Environment Exposure and LTP Induction in the Hippocampus In Vivo Do Not Transfer Faithfully to In Vitro Slices

ERIC Educational Resources Information Center

Eckert, Michael J.; Abraham, Wickliffe C.

2010-01-01

A number of experimental paradigms use in vitro brain slices to test for changes in synaptic transmission and plasticity following a behavioral manipulation. For example, a number of previous studies have reported a variety of effects of environmental enrichment (EE) exposure on field potential responses in hippocampal slices, but in no study was…

Distinct Effects of Nalmefene on Dopamine Uptake Rates and Kappa Opioid Receptor Activity in the Nucleus Accumbens Following Chronic Intermittent Ethanol Exposure

PubMed Central

Rose, Jamie H.; Karkhanis, Anushree N.; Steiniger-Brach, Björn; Jones, Sara R.

2016-01-01

The development of pharmacotherapeutics that reduce relapse to alcohol drinking in patients with alcohol dependence is of considerable research interest. Preclinical data support a role for nucleus accumbens (NAc) κ opioid receptors (KOR) in chronic intermittent ethanol (CIE) exposure-induced increases in ethanol intake. Nalmefene, a high-affinity KOR partial agonist, reduces drinking in at-risk patients and relapse drinking in rodents, potentially due to its effects on NAc KORs. However, the effects of nalmefene on accumbal dopamine transmission and KOR function are poorly understood. We investigated the effects of nalmefene on dopamine transmission and KORs using fast scan cyclic voltammetry in NAc brain slices from male C57BL/6J mice following five weeks of CIE or air exposure. Nalmefene concentration-dependently reduced dopamine release similarly in air and CIE groups, suggesting that dynorphin tone may not be present in brain slices. Further, nalmefene attenuated dopamine uptake rates to a greater extent in brain slices from CIE-exposed mice, suggesting that dopamine transporter-KOR interactions may be fundamentally altered following CIE. Additionally, nalmefene reversed the dopamine-decreasing effects of a maximal concentration of a KOR agonist selectively in brain slices of CIE-exposed mice. It is possible that nalmefene may attenuate withdrawal-induced increases in ethanol consumption by modulation of dopamine transmission through KORs. PMID:27472317

ARGON, XENON, HYDROGEN, AND THE OXYGEN CONSUMPTION AND GLYCOLYSIS OF MOUSE TISSUE SLICES

PubMed Central

South, Frank E.; Cook, Sherburne F.

1954-01-01

The effects of xenon, argon, and hydrogen on the aerobic and anaerobic metabolism of mouse liver, brain, and sarcoma slices have been investigated. Xenon was found to alter the rates of metabolism of these tissues in a manner almost identical with helium. The gas increased the rate of oxygen consumption in all three tissues and significantly depressed that of anaerobic glycolysis in brain and liver. The depression of glycolysis in sarcoma was less pronounced and not highly significant. Although both the magnitude and statistical significance of the effects observed with argon were much smaller, there was a seeming adherence to the general pattern established by xenon and helium. Hydrogen while remaining essentially ineffective insofar as oxygen uptake was concerned, depressed glycolysis in both liver and brain slices but did not significantly affect sarcoma slices. The following points are stressed in the Discussion: (1) the magnitude and direction of effects exerted by helium, argon, xenon, hydrogen, and nitrogen do not conform with the relative values of molecular weight, density, and solubility of these gases; (2) the effect of these gases on tissue metabolism does not necessarily parallel that exerted upon the whole organism. PMID:13118104

Analysis of lipid raft molecules in the living brain slices.

PubMed

Kotani, Norihiro; Nakano, Takanari; Ida, Yui; Ito, Rina; Hashizume, Miki; Yamaguchi, Arisa; Seo, Makoto; Araki, Tomoyuki; Hojo, Yasushi; Honke, Koichi; Murakoshi, Takayuki

2017-08-24

Neuronal plasma membrane has been thought to retain a lot of lipid raft components which play important roles in the neural function. Although the biochemical analyses of lipid raft using brain tissues have been extensively carried out in the past 20 years, many of their experimental conditions do not coincide with those of standard neuroscience researches such as neurophysiology and neuropharmacology. Hence, the physiological methods for lipid raft analysis that can be compatible with general neuroscience have been required. Herein, we developed a system to physiologically analyze ganglioside GM1-enriched lipid rafts in brain tissues using the "Enzyme-Mediated Activation of Radical Sources (EMARS)" method that we reported (Kotani N. et al. Proc. Natl. Acad. Sci. U S A 105, 7405-7409 (2008)). The EMARS method was applied to acute brain slices prepared from mouse brains in aCSF solution using the EMARS probe, HRP-conjugated cholera toxin subunit B, which recognizes ganglioside GM1. The membrane molecules present in the GM1-enriched lipid rafts were then labeled with fluorescein under the physiological condition. The fluorescein-tagged lipid raft molecules called "EMARS products" distributed differentially among various parts of the brain. On the other hand, appreciable differences were not detected among segments along the longitudinal axis of the hippocampus. We further developed a device to label the lipid raft molecules in acute hippocampal slices under two different physiological conditions to detect dynamics of the lipid raft molecules during neural excitation. Using this device, several cell membrane molecules including Thy1, known as a lipid raft resident molecule in neurons, were confirmed by the EMARS method in living hippocampal slices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbleeds in postmortem brains of patients with Alzheimer disease: a T2*-weighted gradient-echo 7.0 T magnetic resonance imaging study.

PubMed

De Reuck, Jacques L; Cordonnier, Charlotte; Deramecourt, Vincent; Auger, Florent; Durieux, Nicolas; Bordet, Regis; Maurage, Claude-Alain; Leys, Didier; Pasquier, Florence

2013-01-01

This study aims to determine the distribution and to quantify microbleeds (MBs) in postmortem brains of patients with Alzheimer disease (AD) on T2*-weighted gradient-echo 7.0 T magnetic resonance imaging. Twenty-eight AD brains were compared with 5 controls. The AD brains were subdivided further: 18 without and 10 with additional severe cerebral amyloid angiopathy (AD-CAA). The distribution and the number of cortical focal signal intensity losses, representing MBs, were assessed on coronal sections at the frontal, the central, and the occipital level of a cerebral hemisphere. MBs prevailed in the central sections (P=0.005) of AD brains without CAA, whereas in AD-CAA brains, they were more frequent in all coronal sections (P≤0.002). They prevailed in the deep cortical layers of the AD brains and of the controls (P≤0.03). They were significantly increased in all cortical layers of the AD-CAA brains (P≤0.04), compared with the controls. MBs prevalence in brains of AD patients had a different topographic distribution according to the absence or presence of severe CAA.

Incorporating Functional Image Information to rpFNA Analysis for Breast Cancer Detection in High-Risk Women

DTIC Science & Technology

2011-03-01

protocol. Unfortunately for this grant project, this approval has come too late to acquire human subjects. Nonetheless, the MMI Lab will continue to...Gaussian filter ) of 10X clinical activity concentration (0.36 µCi/mL) images acquired on Day 1 with (LEFT) VAOR, (CENTER) TPB and (RIGHT) PROJSINE...trajectories. (ROW 3) Coronal and (ROW 4) transverse slices (smoothed with a Gaussian filter ) showing the placement and size of the VOI used to

The Effects of Dopamine and Estrogen Upon Cortical Parvalbumin Expression

DTIC Science & Technology

2001-01-01

Tavedi and Susan Alcala for their valuable technical assistance . This work was supported by NIH NS27038 and USUHS RO7096 to Linda L. Porter. 7 Abstract...postnatal days. All procedures were done in accordance with the NIH guide for the care and use of animals as outlined in a protocol approved by the USUHS...250 µm coronal sections. Slices were washed into cold dissecting medium and separated by gentle agitation using a fire polished wide aperture pipette

Three‐dimensional motion corrected sensitivity encoding reconstruction for multi‐shot multi‐slice MRI: Application to neonatal brain imaging

PubMed Central

Hughes, Emer J.; Hutter, Jana; Price, Anthony N.; Hajnal, Joseph V.

2017-01-01

Purpose To introduce a methodology for the reconstruction of multi‐shot, multi‐slice magnetic resonance imaging able to cope with both within‐plane and through‐plane rigid motion and to describe its application in structural brain imaging. Theory and Methods The method alternates between motion estimation and reconstruction using a common objective function for both. Estimates of three‐dimensional motion states for each shot and slice are gradually refined by improving on the fit of current reconstructions to the partial k‐space information from multiple coils. Overlapped slices and super‐resolution allow recovery of through‐plane motion and outlier rejection discards artifacted shots. The method is applied to T 2 and T 1 brain scans acquired in different views. Results The procedure has greatly diminished artifacts in a database of 1883 neonatal image volumes, as assessed by image quality metrics and visual inspection. Examples showing the ability to correct for motion and robustness against damaged shots are provided. Combination of motion corrected reconstructions for different views has shown further artifact suppression and resolution recovery. Conclusion The proposed method addresses the problem of rigid motion in multi‐shot multi‐slice anatomical brain scans. Tests on a large collection of potentially corrupted datasets have shown a remarkable image quality improvement. Magn Reson Med 79:1365–1376, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. PMID:28626962

De Novo Synthesized Estradiol Protects against Methylmercury-Induced Neurotoxicity in Cultured Rat Hippocampal Slices

PubMed Central

Ishihara, Yasuhiro; Komatsu, Shota; Munetsuna, Eiji; Onizaki, Masahiro; Ishida, Atsuhiko; Kawato, Suguru; Mukuda, Takao

2013-01-01

Background Estrogen, a class of female sex steroids, is neuroprotective. Estrogen is synthesized in specific areas of the brain. There is a possibility that the de novo synthesized estrogen exerts protective effect in brain, although direct evidence for the neuroprotective function of brain-synthesized estrogen has not been clearly demonstrated. Methylmercury (MeHg) is a neurotoxin that induces neuronal degeneration in the central nervous system. The neurotoxicity of MeHg is region-specific, and the molecular mechanisms for the selective neurotoxicity are not well defined. In this study, the protective effect of de novo synthesized 17β-estradiol on MeHg-induced neurotoxicity in rat hippocampus was examined. Methodology/Principal Findings Neurotoxic effect of MeHg on hippocampal organotypic slice culture was quantified by propidium iodide fluorescence imaging. Twenty-four-hour treatment of the slices with MeHg caused cell death in a dose-dependent manner. The toxicity of MeHg was attenuated by pre-treatment with exogenously added estradiol. The slices de novo synthesized estradiol. The estradiol synthesis was not affected by treatment with 1 µM MeHg. The toxicity of MeHg was enhanced by inhibition of de novo estradiol synthesis, and the enhancement of toxicity was recovered by the addition of exogenous estradiol. The neuroprotective effect of estradiol was inhibited by an estrogen receptor (ER) antagonist, and mimicked by pre-treatment of the slices with agonists for ERα and ERβ, indicating the neuroprotective effect was mediated by ERs. Conclusions/Significance Hippocampus de novo synthesized estradiol protected hippocampal cells from MeHg-induced neurotoxicity via ERα- and ERβ-mediated pathways. The self-protective function of de novo synthesized estradiol might be one of the possible mechanisms for the selective sensitivity of the brain to MeHg toxicity. PMID:23405170

Correcting for strong eddy current induced B0 modulation enables two-spoke RF pulse design with parallel transmission: demonstration at 9.4T in the human brain.

PubMed

Wu, Xiaoping; Adriany, Gregor; Ugurbil, Kamil; Van de Moortele, Pierre-Francois

2013-01-01

Successful implementation of homogeneous slice-selective RF excitation in the human brain at 9.4T using 16-channel parallel transmission (pTX) is demonstrated. A novel three-step pulse design method incorporating fast real-time measurement of eddy current induced B0 variations as well as correction of resulting phase errors during excitation is described. To demonstrate the utility of the proposed method, phantom and in-vivo experiments targeting a uniform excitation in an axial slice were conducted using two-spoke pTX pulses. Even with the pre-emphasis activated, eddy current induced B0 variations with peak-to-peak values greater than 4 kHz were observed on our system during the rapid switches of slice selective gradients. This large B0 variation, when not corrected, resulted in drastically degraded excitation fidelity with the coefficient of variation (CV) of the flip angle calculated for the region of interest being large (~ 12% in the phantom and ~ 35% in the brain). By comparison, excitation fidelity was effectively restored, and satisfactory flip angle uniformity was achieved when using the proposed method, with the CV value reduced to ~ 3% in the phantom and ~ 8% in the brain. Additionally, experimental results were in good agreement with the numerical predictions obtained from Bloch simulations. Slice-selective flip angle homogenization in the human brain at 9.4T using 16-channel 3D spoke pTX pulses is achievable despite of large eddy current induced excitation phase errors; correcting for the latter was critical in this success.

Heterogeneous histopathology of cortical microbleeds in cerebral amyloid angiopathy.

PubMed

van Veluw, Susanne J; Biessels, Geert Jan; Klijn, Catharina J M; Rozemuller, Annemieke J M

2016-03-01

To investigate the histopathologic substrate of microbleeds detected on 7T postmortem MRI in autopsy cases with severe cerebral amyloid angiopathy (CAA) and Alzheimer pathology. Five decedents (mean age at death 79.6 ± 5.7 years) with documented severe CAA and Alzheimer pathology on standard neuropathologic examination were selected from a local database. Formalin-fixed coronal brain slices were scanned at 7T MRI, including high-resolution T2- and T2*-weighted sequences. Representative microbleeds from each case were sampled for histopathologic analysis, including the presence of blood, blood breakdown products, and markers of ischemic tissue injury. On MRI, we identified >300 cortical and 4 subcortical microbleeds. Two out of 15 sampled cortical microbleeds corresponded histologically to erythrocytes (suggestive of recent hemorrhages), 4 to vasculopathies (fibrinoid necrosis in 3 and a cavernoma) without substantial parenchymal tissue injury, and 9 to accumulations of iron-positive siderophages without erythrocytes (suggestive of old hemorrhages) combined with mild to moderate degrees of chronic ischemic tissue injury. This study provides evidence for heterogeneous pathologic substrates and possibly different pathophysiologic mechanisms underlying MRI-observed cortical microbleeds in the context of advanced CAA and Alzheimer disease. © 2016 American Academy of Neurology.

COMPARISON OF ADAPTIVE STATISTICAL ITERATIVE RECONSTRUCTION (ASIR™) AND MODEL-BASED ITERATIVE RECONSTRUCTION (VEO™) FOR PAEDIATRIC ABDOMINAL CT EXAMINATIONS: AN OBSERVER PERFORMANCE STUDY OF DIAGNOSTIC IMAGE QUALITY.

PubMed

Hultenmo, Maria; Caisander, Håkan; Mack, Karsten; Thilander-Klang, Anne

2016-06-01

The diagnostic image quality of 75 paediatric abdominal computed tomography (CT) examinations reconstructed with two different iterative reconstruction (IR) algorithms-adaptive statistical IR (ASiR™) and model-based IR (Veo™)-was compared. Axial and coronal images were reconstructed with 70 % ASiR with the Soft™ convolution kernel and with the Veo algorithm. The thickness of the reconstructed images was 2.5 or 5 mm depending on the scanning protocol used. Four radiologists graded the delineation of six abdominal structures and the diagnostic usefulness of the image quality. The Veo reconstruction significantly improved the visibility of most of the structures compared with ASiR in all subgroups of images. For coronal images, the Veo reconstruction resulted in significantly improved ratings of the diagnostic use of the image quality compared with the ASiR reconstruction. This was not seen for the axial images. The greatest improvement using Veo reconstruction was observed for the 2.5 mm coronal slices. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Non-signalling energy use in the developing rat brain

PubMed Central

Engl, Elisabeth; Jolivet, Renaud; Hall, Catherine N

2016-01-01

Energy use in the brain constrains its information processing power, but only about half the brain's energy consumption is directly related to information processing. Evidence for which non-signalling processes consume the rest of the brain's energy has been scarce. For the first time, we investigated the energy use of the brain's main non-signalling tasks with a single method. After blocking each non-signalling process, we measured oxygen level changes in juvenile rat brain slices with an oxygen-sensing microelectrode and calculated changes in oxygen consumption throughout the slice using a modified diffusion equation. We found that the turnover of the actin and microtubule cytoskeleton, followed by lipid synthesis, are significant energy drains, contributing 25%, 22% and 18%, respectively, to the rate of oxygen consumption. In contrast, protein synthesis is energetically inexpensive. We assess how these estimates of energy expenditure relate to brain energy use in vivo, and how they might differ in the mature brain. PMID:27170699

Identification and characterisation of midbrain nuclei using optimised functional magnetic resonance imaging

PubMed Central

Limbrick-Oldfield, Eve H.; Brooks, Jonathan C.W.; Wise, Richard J.S.; Padormo, Francesco; Hajnal, Jo V.; Beckmann, Christian F.; Ungless, Mark A.

2012-01-01

Localising activity in the human midbrain with conventional functional MRI (fMRI) is challenging because the midbrain nuclei are small and located in an area that is prone to physiological artefacts. Here we present a replicable and automated method to improve the detection and localisation of midbrain fMRI signals. We designed a visual fMRI task that was predicted would activate the superior colliculi (SC) bilaterally. A limited number of coronal slices were scanned, orientated along the long axis of the brainstem, whilst simultaneously recording cardiac and respiratory traces. A novel anatomical registration pathway was used to optimise the localisation of the small midbrain nuclei in stereotactic space. Two additional structural scans were used to improve registration between functional and structural T1-weighted images: an echo-planar image (EPI) that matched the functional data but had whole-brain coverage, and a whole-brain T2-weighted image. This pathway was compared to conventional registration pathways, and was shown to significantly improve midbrain registration. To reduce the physiological artefacts in the functional data, we estimated and removed structured noise using a modified version of a previously described physiological noise model (PNM). Whereas a conventional analysis revealed only unilateral SC activity, the PNM analysis revealed the predicted bilateral activity. We demonstrate that these methods improve the measurement of a biologically plausible fMRI signal. Moreover they could be used to investigate the function of other midbrain nuclei. PMID:21867762

MALDI mass spectrometry imaging of bioactive lipids in mouse brain with a Synapt G2-S mass spectrometer operated at elevated pressure: improving the analytical sensitivity and the lateral resolution to ten micrometers.

PubMed

Kettling, Hans; Vens-Cappell, Simeon; Soltwisch, Jens; Pirkl, Alexander; Haier, Jörg; Müthing, Johannes; Dreisewerd, Klaus

2014-08-05

Mass spectrometers from the Synapt-G1/G2 family (Waters) are widely employed for matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). A lateral resolution of about 50 μm is typically achieved with these instruments, that is, however, below the often desired cellular resolution. Here, we show the first MALDI-MSI examples demonstrating a lateral resolution of about ten micrometers obtained with a Synapt G2-S HDMS mass spectrometer without oversampling. This improvement became possible by laser beam shaping using a 4:1 beam expander and a circular aperture for spatial mode filtering and by replacement of the default focusing lens. We used dithranol as an effective matrix for imaging of acidic lipids such as sulfatides, gangliosides, and phosphatidylinositols in the negative ion mode. At the same time, the matrix enables MS imaging of more basic lipids in the positive ion mode. Uniform matrix coatings with crystals having average dimensions between 0.5 and 3 μm were obtained upon spraying a chloroform/methanol matrix solution. Increasing the cooling gas pressure in the MALDI ion source after adding an additional gas line was furthermore found to increase the ion abundances of labile lipids such as gangliosides. The combined characteristics are demonstrated with the MALDI-MSI analysis of fine structures in coronal mouse brain slices.

Dietary fats significantly influence the survival of penumbral neurons in a rat model of chronic ischemic by modifying lipid mediators, inflammatory biomarkers, NOS production, and redox-dependent apoptotic signals.

PubMed

Lausada, Natalia; Arnal, Nathalie; Astiz, Mariana; Marín, María Cristina; Lofeudo, Juan Manuel; Stringa, Pablo; Tacconi de Alaniz, María J; Tacconi de Gómez Dumm, Nelva; Hurtado de Catalfo, Graciela; Cristalli de Piñero, Norma; Pallanza de Stringa, María Cristina; Illara de Bozzolo, Eva María; Bozzarello, Enrique Gustavo; Cristalli, Diana Olga; Marra, Carlos Alberto

2015-01-01

Brain stroke is the third most important cause of death in developed countries. We studied the effect of different dietary lipids on the outcome of a permanent ischemic stroke rat model. Wistar rats were fed diets containing 7% commercial oils (S, soybean; O, olive; C, coconut; G, grape seed) for 35 d. Stroke was induced by permanent middle cerebral artery occlusion. Coronal slices from ischemic brains and sham-operated animals were supravitally stained. Penumbra and core volumes were calculated by image digitalization after 24, 48, and 72 h poststroke. Homogenates and mitochondrial fractions were prepared from different zones and analyzed by redox status, inflammatory markers, ceramide, and arachidonate content, phospholipase A2, NOS, and proteases. Soybean (S) and G diets were mainly prooxidative and proinflammatory by increasing the liberation of arachidonate and its transformation into prostaglandins. O was protective in terms of redox homeostatic balance, minor increases in lipid and protein damage, conservation of reduced glutathione, protective activation of NOS in penumbra, and net ratio of anti-to proinflammatory cytokines. Apoptosis (caspase-3, milli- and microcalpains) was less activated by O than by any other diet. Dietary lipids modulate NOS and PLA2 activities, ceramide production, and glutathione import into the mitochondrial matrix, finally determining the activation of the two main protease systems involved in programmed cell death. Olive oil appears to be a biological source for the isolation of protective agents that block the expansion of brain core at the expense of penumbral neurons. Copyright © 2015 Elsevier Inc. All rights reserved.

Polyethylene glycol restores axonal conduction after corpus callosum transection.

PubMed

Bamba, Ravinder; Riley, D Colton; Boyer, Richard B; Pollins, Alonda C; Shack, R Bruce; Thayer, Wesley P

2017-05-01

Polyethylene glycol (PEG) has been shown to restore axonal continuity after peripheral nerve transection in animal models. We hypothesized that PEG can also restore axonal continuity in the central nervous system. In this current experiment, coronal sectioning of the brains of Sprague-Dawley rats was performed after animal sacrifice. 3Brain high-resolution microelectrode arrays (MEA) were used to measure mean firing rate (MFR) and peak amplitude across the corpus callosum of the ex-vivo brain slices. The corpus callosum was subsequently transected and repeated measurements were performed. The cut ends of the corpus callosum were still apposite at this time. A PEG solution was applied to the injury site and repeated measurements were performed. MEA measurements showed that PEG was capable of restoring electrophysiology signaling after transection of central nerves. Before injury, the average MFRs at the ipsilateral, midline, and contralateral corpus callosum were 0.76, 0.66, and 0.65 spikes/second, respectively, and the average peak amplitudes were 69.79, 58.68, and 49.60 μV, respectively. After injury, the average MFRs were 0.71, 0.14, and 0.25 spikes/second, respectively and peak amplitudes were 52.11, 8.98, and 16.09 μV, respectively. After application of PEG, there were spikes in MFR and peak amplitude at the injury site and contralaterally. The average MFRs were 0.75, 0.55, and 0.47 spikes/second at the ipsilateral, midline, and contralateral corpus callosum, respectively and peak amplitudes were 59.44, 45.33, 40.02 μV, respectively. There were statistically differences in the average MFRs and peak amplitudes between the midline and non-midline corpus callosum groups ( P < 0.01, P < 0.05). These findings suggest that PEG restores axonal conduction between severed central nerves, potentially representing axonal fusion.

Polyethylene glycol restores axonal conduction after corpus callosum transection

PubMed Central

Bamba, Ravinder; Riley, D. Colton; Boyer, Richard B.; Pollins, Alonda C.; Shack, R. Bruce; Thayer, Wesley P.

2017-01-01

Polyethylene glycol (PEG) has been shown to restore axonal continuity after peripheral nerve transection in animal models. We hypothesized that PEG can also restore axonal continuity in the central nervous system. In this current experiment, coronal sectioning of the brains of Sprague-Dawley rats was performed after animal sacrifice. 3Brain high-resolution microelectrode arrays (MEA) were used to measure mean firing rate (MFR) and peak amplitude across the corpus callosum of the ex-vivo brain slices. The corpus callosum was subsequently transected and repeated measurements were performed. The cut ends of the corpus callosum were still apposite at this time. A PEG solution was applied to the injury site and repeated measurements were performed. MEA measurements showed that PEG was capable of restoring electrophysiology signaling after transection of central nerves. Before injury, the average MFRs at the ipsilateral, midline, and contralateral corpus callosum were 0.76, 0.66, and 0.65 spikes/second, respectively, and the average peak amplitudes were 69.79, 58.68, and 49.60 μV, respectively. After injury, the average MFRs were 0.71, 0.14, and 0.25 spikes/second, respectively and peak amplitudes were 52.11, 8.98, and 16.09 μV, respectively. After application of PEG, there were spikes in MFR and peak amplitude at the injury site and contralaterally. The average MFRs were 0.75, 0.55, and 0.47 spikes/second at the ipsilateral, midline, and contralateral corpus callosum, respectively and peak amplitudes were 59.44, 45.33, 40.02 μV, respectively. There were statistically differences in the average MFRs and peak amplitudes between the midline and non-midline corpus callosum groups (P < 0.01, P < 0.05). These findings suggest that PEG restores axonal conduction between severed central nerves, potentially representing axonal fusion. PMID:28616031

Immature rat brain slices exposed to oxygen-glucose deprivation as an in vitro model of neonatal hypoxic-ischemic encephalopathy.

PubMed

Fernández-López, David; Martínez-Orgado, José; Casanova, Ignacio; Bonet, Bartolomé; Leza, Juan Carlos; Lorenzo, Pedro; Moro, Maria Angeles; Lizasoain, Ignacio

2005-06-30

To analyze whether exposure to oxygen-glucose deprivation (OGD) of immature rat brain slices might reproduce the main pathophysiologic events leading to neuronal death in neonatal hypoxic-ischemic encephalopathy (NHIE), 500 microm-thick brain slices were obtained from 7-day-old Wistar rats, and incubated in oxygenated physiological solution. In OGD group, oxygen and glucose were removed from the medium for 10-30 min (n = 25); then, slices were re-incubated in normal medium. In control group the medium composition remained unchanged (CG, n = 30). Medium samples were obtained every 30 min for 3 h. To analyze neuronal damage, slices were stained with Nissl and CA1 area of hippocampus and cortex were observed under microscopy. In addition, neuronal death was quantified as LDH released to the medium determined by spectrophotometry. Additionally, medium glutamate (Glu) levels were determined by HPLC and those of TNFalpha by ELISA, whereas inducible nitric oxide synthase expression was determined by Western blot performed on slices homogenate. Optimal OGD time was established in 20 min. After OGD, a significant decrease in the number of neurones in hippocampus and cortex was observed. LDH release was maximal at 30 min, when it was five-fold greater than in CG. Furthermore, medium Glu concentrations were 200 times greater than CG levels at the end of OGD period. A linear relationship between Glu and LDH release was demonstrated. Finally, 3 h after OGD a significant induction of iNOS as well as an increase in TNFalpha release were observed. In conclusion, OGD appears as a feasible and reproducible in vitro model, leading to a neuronal damage, which is physiopathologically similar to that found in NHIE.

Multi-slice computed tomography-assisted endoscopic transsphenoidal surgery for pituitary macroadenoma: a comparison with conventional microscopic transsphenoidal surgery.

PubMed

Tosaka, Masahiko; Nagaki, Tomohito; Honda, Fumiaki; Takahashi, Katsumasa; Yoshimoto, Yuhei

2015-11-01

Intraoperative computed tomography (iCT) is a reliable method for the detection of residual tumour, but previous single-slice low-resolution computed tomography (CT) without coronal or sagittal reconstructions was not of adequate quality for clinical use. The present study evaluated the results of multi-slice iCT-assisted endoscopic transsphenoidal surgery for pituitary macroadenoma. This retrospective study included 30 consecutive patients with newly diagnosed or recurrent pituitary macroadenoma with supradiaphragmatic extension who underwent endoscopic transsphenoidal surgery using iCT (eTSS+iCT group), and control 30 consecutive patients who underwent conventional endoscope-assisted transsphenoidal surgery (cTSS group). The tumour volume was calculated by multiplying the tumour area by the slice thickness. Visual acuity and visual field were estimated by the visual impairment score (VIS). The resection extent, (preoperative tumour volume - postoperative residual tumour volume)/preoperative tumour volume, was 98.9% (median) in the eTSS+iCT group and 91.7% in the cTSS group, and had significant difference between the groups (P = 0.04). Greater than 95 and >90% removal rates were significantly higher in the eTSS+iCT group than in the cTSS group (P = 0.02 and P = 0.001, respectively). However, improvement in VIS showed no significant difference between the groups. The rate of complications also showed no significant difference. Multi-slice iCT-assisted endoscopic transsphenoidal surgery may improve the resection extent of pituitary macroadenoma. Multi-slice iCT may have advantages over intraoperative magnetic resonance imaging in less expensive, short acquisition time, and that special protection against magnetic fields is not needed.

Synchrotron X-ray microtransections: a non invasive approach for epileptic seizures arising from eloquent cortical areas

PubMed Central

Pouyatos, B.; Nemoz, C.; Chabrol, T.; Potez, M.; Bräuer, E.; Renaud, L.; Pernet-Gallay, K.; Estève, F.; David, O.; Kahane, P.; Laissue, J. A.; Depaulis, A.; Serduc, R.

2016-01-01

Synchrotron-generated X-ray (SRX) microbeams deposit high radiation doses to submillimetric targets whilst minimizing irradiation of neighboring healthy tissue. We developed a new radiosurgical method which demonstrably transects cortical brain tissue without affecting adjacent regions. We made such image-guided SRX microtransections in the left somatosensory cortex in a rat model of generalized epilepsy using high radiation doses (820 Gy) in thin (200 μm) parallel slices of tissue. This procedure, targeting the brain volume from which seizures arose, altered the abnormal neuronal activities for at least 9 weeks, as evidenced by a decrease of seizure power and coherence between tissue slices in comparison to the contralateral cortex. The brain tissue located between transections stayed histologically normal, while the irradiated micro-slices remained devoid of myelin and neurons two months after irradiation. This pre-clinical proof of concept highlights the translational potential of non-invasive SRX transections for treating epilepsies that are not eligible for resective surgery. PMID:27264273

Synchrotron X-ray microtransections: a non invasive approach for epileptic seizures arising from eloquent cortical areas

NASA Astrophysics Data System (ADS)

Pouyatos, B.; Nemoz, C.; Chabrol, T.; Potez, M.; Bräuer, E.; Renaud, L.; Pernet-Gallay, K.; Estève, F.; David, O.; Kahane, P.; Laissue, J. A.; Depaulis, A.; Serduc, R.

2016-06-01

Synchrotron-generated X-ray (SRX) microbeams deposit high radiation doses to submillimetric targets whilst minimizing irradiation of neighboring healthy tissue. We developed a new radiosurgical method which demonstrably transects cortical brain tissue without affecting adjacent regions. We made such image-guided SRX microtransections in the left somatosensory cortex in a rat model of generalized epilepsy using high radiation doses (820 Gy) in thin (200 μm) parallel slices of tissue. This procedure, targeting the brain volume from which seizures arose, altered the abnormal neuronal activities for at least 9 weeks, as evidenced by a decrease of seizure power and coherence between tissue slices in comparison to the contralateral cortex. The brain tissue located between transections stayed histologically normal, while the irradiated micro-slices remained devoid of myelin and neurons two months after irradiation. This pre-clinical proof of concept highlights the translational potential of non-invasive SRX transections for treating epilepsies that are not eligible for resective surgery.

BAD and KATP channels regulate neuron excitability and epileptiform activity

PubMed Central

Fernández-Agüera, María Carmen; Nathwani, Nidhi; Lahmann, Carolina; Burnham, Veronica L

2018-01-01

Brain metabolism can profoundly influence neuronal excitability. Mice with genetic deletion or alteration of Bad (BCL-2 agonist of cell death) exhibit altered brain-cell fuel metabolism, accompanied by resistance to acutely induced epileptic seizures; this seizure protection is mediated by ATP-sensitive potassium (KATP) channels. Here we investigated the effect of BAD manipulation on KATP channel activity and excitability in acute brain slices. We found that BAD’s influence on neuronal KATP channels was cell-autonomous and directly affected dentate granule neuron (DGN) excitability. To investigate the role of neuronal KATP channels in the anticonvulsant effects of BAD, we imaged calcium during picrotoxin-induced epileptiform activity in entorhinal-hippocampal slices. BAD knockout reduced epileptiform activity, and this effect was lost upon knockout or pharmacological inhibition of KATP channels. Targeted BAD knockout in DGNs alone was sufficient for the antiseizure effect in slices, consistent with a ‘dentate gate’ function that is reinforced by increased KATP channel activity. PMID:29368690

Two-photon imaging in living brain slices.

PubMed

Mainen, Z F; Maletic-Savatic, M; Shi, S H; Hayashi, Y; Malinow, R; Svoboda, K

1999-06-01

Two-photon excitation laser scanning microscopy (TPLSM) has become the tool of choice for high-resolution fluorescence imaging in intact neural tissues. Compared with other optical techniques, TPLSM allows high-resolution imaging and efficient detection of fluorescence signal with minimal photobleaching and phototoxicity. The advantages of TPLSM are especially pronounced in highly scattering environments such as the brain slice. Here we describe our approaches to imaging various aspects of synaptic function in living brain slices. To combine several imaging modes together with patch-clamp electrophysiological recordings we found it advantageous to custom-build an upright microscope. Our design goals were primarily experimental convenience and efficient collection of fluorescence. We describe our TPLSM imaging system and its performance in detail. We present dynamic measurements of neuronal morphology of neurons expressing green fluorescent protein (GFP) and GFP fusion proteins as well as functional imaging of calcium dynamics in individual dendritic spines. Although our microscope is a custom instrument, its key advantages can be easily implemented as a modification of commercial laser scanning microscopes. Copyright 1999 Academic Press.

Anatomy and histology of the sacroiliac joints.

PubMed

Egund, Niels; Jurik, Anne Grethe

2014-07-01

The anatomy of joints provides an important basis for understanding the nature and imaging of pathologic lesions and their imaging appearance. This applies especially to the sacroiliac (SI) joints, which play a major role in the diagnosis of spondyloarthritis. They are composed of two different joint portions, a cartilage-covered portion ventrally and a ligamentous portion dorsally, and thus rather complex anatomically. Knowledge of anatomy and the corresponding normal imaging findings are important in the imaging diagnosis of sacroiliitis, especially by MR imaging. A certain distinction between the two joint portions by MR imaging is only obtainable by axial slice orientation. Together with a perpendicular coronal slice orientation, it provides adequate anatomical information and thereby a possibility for detecting the anatomical site of disease-specific characteristics and normal variants simulating disease. This overview describes current knowledge about the normal macroscopic and microscopic anatomy of the SI joints. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Fetal brain volumetry through MRI volumetric reconstruction and segmentation

PubMed Central

Estroff, Judy A.; Barnewolt, Carol E.; Connolly, Susan A.; Warfield, Simon K.

2013-01-01

Purpose Fetal MRI volumetry is a useful technique but it is limited by a dependency upon motion-free scans, tedious manual segmentation, and spatial inaccuracy due to thick-slice scans. An image processing pipeline that addresses these limitations was developed and tested. Materials and methods The principal sequences acquired in fetal MRI clinical practice are multiple orthogonal single-shot fast spin echo scans. State-of-the-art image processing techniques were used for inter-slice motion correction and super-resolution reconstruction of high-resolution volumetric images from these scans. The reconstructed volume images were processed with intensity non-uniformity correction and the fetal brain extracted by using supervised automated segmentation. Results Reconstruction, segmentation and volumetry of the fetal brains for a cohort of twenty-five clinically acquired fetal MRI scans was done. Performance metrics for volume reconstruction, segmentation and volumetry were determined by comparing to manual tracings in five randomly chosen cases. Finally, analysis of the fetal brain and parenchymal volumes was performed based on the gestational age of the fetuses. Conclusion The image processing pipeline developed in this study enables volume rendering and accurate fetal brain volumetry by addressing the limitations of current volumetry techniques, which include dependency on motion-free scans, manual segmentation, and inaccurate thick-slice interpolation. PMID:20625848

Imaging human brain cyto- and myelo-architecture with quantitative OCT (Conference Presentation)

NASA Astrophysics Data System (ADS)

Boas, David A.; Wang, Hui; Konukoglu, Ender; Fischl, Bruce; Sakadzic, Sava; Magnain, Caroline V.

2017-02-01

No current imaging technology allows us to directly and without significant distortion visualize the microscopic and defining anatomical features of the human brain. Ex vivo histological techniques can yield exquisite planar images, but the cutting, mounting and staining that are required components of this type of imaging induce distortions that are different for each slice, introducing cross-slice differences that prohibit true 3D analysis. We are overcoming this issue by utilizing Optical Coherence Tomography (OCT) with the goal to image whole human brain cytoarchitectural and laminar properties with potentially 3.5 µm resolution in block-face without the need for exogenous staining. From the intrinsic scattering contrast of the brain tissue, OCT gives us images that are comparable to Nissl stains, but without the distortions introduced in standard histology as the OCT images are acquired from the block face prior to slicing and thus without the need for subsequent staining and mounting. We have shown that laminar and cytoarchitectural properties of the brain can be characterized with OCT just as well as with Nissl staining. We will present our recent advances to improve the axial resolution while maintaining contrast; improvements afforded by speckle reduction procedures; and efforts to obtain quantitative maps of the optical scattering coefficient, an intrinsic property of the tissue.

Investigation of the moving structures in a coronal bright point

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ning, Zongjun; Guo, Yang, E-mail: ningzongjun@pmo.ac.cn

2014-10-10

We have explored the moving structures in a coronal bright point (CBP) observed by the Solar Dynamic Observatory Atmospheric Imaging Assembly (AIA) on 2011 March 5. This CBP event has a lifetime of ∼20 minutes and is bright with a curved shape along a magnetic loop connecting a pair of negative and positive fields. AIA imaging observations show that a lot of bright structures are moving intermittently along the loop legs toward the two footpoints from the CBP brightness core. Such moving bright structures are clearly seen at AIA 304 Å. In order to analyze their features, the CBP ismore » cut along the motion direction with a curved slit which is wide enough to cover the bulk of the CBP. After integrating the flux along the slit width, we get the spacetime slices at nine AIA wavelengths. The oblique streaks starting from the edge of the CBP brightness core are identified as moving bright structures, especially on the derivative images of the brightness spacetime slices. They seem to originate from the same position near the loop top. We find that these oblique streaks are bi-directional, simultaneous, symmetrical, and periodic. The average speed is about 380 km s{sup –1}, and the period is typically between 80 and 100 s. Nonlinear force-free field extrapolation shows the possibility that magnetic reconnection takes place during the CBP, and our findings indicate that these moving bright structures could be the observational outflows after magnetic reconnection in the CBP.« less

A Device for Long-Term Perfusion, Imaging, and Electrical Interfacing of Brain Tissue In vitro

PubMed Central

Killian, Nathaniel J.; Vernekar, Varadraj N.; Potter, Steve M.; Vukasinovic, Jelena

2016-01-01

Distributed microelectrode array (MEA) recordings from consistent, viable, ≥500 μm thick tissue preparations over time periods from days to weeks may aid in studying a wide range of problems in neurobiology that require in vivo-like organotypic morphology. Existing tools for electrically interfacing with organotypic slices do not address necrosis that inevitably occurs within thick slices with limited diffusion of nutrients and gas, and limited removal of waste. We developed an integrated device that enables long-term maintenance of thick, functionally active, brain tissue models using interstitial perfusion and distributed recordings from thick sections of explanted tissue on a perforated multi-electrode array. This novel device allows for automated culturing, in situ imaging, and extracellular multi-electrode interfacing with brain slices, 3-D cell cultures, and potentially other tissue culture models. The device is economical, easy to assemble, and integrable with standard electrophysiology tools. We found that convective perfusion through the culture thickness provided a functional benefit to the preparations as firing rates were generally higher in perfused cultures compared to their respective unperfused controls. This work is a step toward the development of integrated tools for days-long experiments with more consistent, healthier, thicker, and functionally more active tissue cultures with built-in distributed electrophysiological recording and stimulation functionality. The results may be useful for the study of normal processes, pathological conditions, and drug screening strategies currently hindered by the limitations of acute (a few hours long) brain slice preparations. PMID:27065793

Utility of coronal contrast-enhanced fat-suppressed FLAIR in the evaluation of optic neuropathy and atrophy.

PubMed

Boegel, Kevin H; Tyan, Andrew E; Iyer, Veena R; Rykken, Jeffrey B; McKinney, Alexander M

2017-01-01

Evaluating chronic sequelae of optic neuritis, such as optic neuropathy with or without optic nerve atrophy, can be challenging on whole brain MRI. This study evaluated the utility of dedicated coronal contrast-enhanced fat-suppressed FLAIR (CE-FS-FLAIR) MR imaging to detect optic neuropathy and optic nerve atrophy. Over 4.5 years, a 3 mm coronal CE-FS-FLAIR sequence at 1.5T was added to the routine brain MRIs of 124 consecutive patients, 102 of whom had suspected or known demyelinating disease. Retrospective record reviews confirmed that 28 of these 102 had documented onset of optic neuritis >4 weeks prior to the brain MRI. These 28 were compared to the other 22 ("controls") of the 124 patients who lacked a history of demyelinating disease or visual symptoms. Using coronal CE-FS-FLAIR, two neuroradiologists separately graded each optic nerve (n = 50 patients, 100 total nerves) as either negative, equivocal, or positive for optic neuropathy or atrophy. The scoring was later repeated. The mean time from acute optic neuritis onset to MRI was 4.1 ± 4.6 years (range 34 days-17.4 years). Per individual nerve grading, the range of sensitivity, specificity, and accuracy of coronal CE-FS-FLAIR in detecting optic neuropathy was 71.4-77.1%, 93.8-95.4%, and 85.5-89.0%, respectively, with strong interobserver (k = 0.667 - 0.678, p < 0.0001), and intraobserver (k = 0.706 - 0.763, p < 0.0001) agreement. For optic atrophy, interobserver agreement was moderate (k = 0.437 - 0.484, p < 0.0001), while intraobserver agreement was moderate-strong (k = 0.491 - 0.596, p < 0.0001). Coronal CE-FS-FLAIR is quite specific in detecting optic neuropathy years after the onset of acute optic neuritis, but is less useful in detecting optic nerve atrophy.

Silicon chip with capacitors and transistors for interfacing organotypic brain slice of rat hippocampus.

PubMed

Hutzler, Michael; Fromherz, Peter

2004-04-01

Probing projections between brain areas and their modulation by synaptic potentiation requires dense arrays of contacts for noninvasive electrical stimulation and recording. Semiconductor technology is able to provide planar arrays with high spatial resolution to be used with planar neuronal structures such as organotypic brain slices. To address basic methodical issues we developed a silicon chip with simple arrays of insulated capacitors and field-effect transistors for stimulation of neuronal activity and recording of evoked field potentials. Brain slices from rat hippocampus were cultured on that substrate. We achieved local stimulation of the CA3 region by applying defined voltage pulses to the chip capacitors. Recording of resulting local field potentials in the CA1 region was accomplished with transistors. The relationship between stimulation and recording was rationalized by a sheet conductor model. By combining a row of capacitors with a row of transistors we determined a simple stimulus-response matrix from CA3 to CA1. Possible contributions of inhomogeneities of synaptic projection, of tissue structure and of neuroelectronic interfacing were considered. The study provides the basis for a development of semiconductor chips with high spatial resolution that are required for long-term studies of topographic mapping.

Three-dimensional inversion recovery manganese-enhanced MRI of mouse brain using super-resolution reconstruction to visualize nuclei involved in higher brain function.

PubMed

Poole, Dana S; Plenge, Esben; Poot, Dirk H J; Lakke, Egbert A J F; Niessen, Wiro J; Meijering, Erik; van der Weerd, Louise

2014-07-01

The visualization of activity in mouse brain using inversion recovery spin echo (IR-SE) manganese-enhanced MRI (MEMRI) provides unique contrast, but suffers from poor resolution in the slice-encoding direction. Super-resolution reconstruction (SRR) is a resolution-enhancing post-processing technique in which multiple low-resolution slice stacks are combined into a single volume of high isotropic resolution using computational methods. In this study, we investigated, first, whether SRR can improve the three-dimensional resolution of IR-SE MEMRI in the slice selection direction, whilst maintaining or improving the contrast-to-noise ratio of the two-dimensional slice stacks. Second, the contrast-to-noise ratio of SRR IR-SE MEMRI was compared with a conventional three-dimensional gradient echo (GE) acquisition. Quantitative experiments were performed on a phantom containing compartments of various manganese concentrations. The results showed that, with comparable scan times, the signal-to-noise ratio of three-dimensional GE acquisition is higher than that of SRR IR-SE MEMRI. However, the contrast-to-noise ratio between different compartments can be superior with SRR IR-SE MEMRI, depending on the chosen inversion time. In vivo experiments were performed in mice receiving manganese using an implanted osmotic pump. The results showed that SRR works well as a resolution-enhancing technique in IR-SE MEMRI experiments. In addition, the SRR image also shows a number of brain structures that are more clearly discernible from the surrounding tissues than in three-dimensional GE acquisition, including a number of nuclei with specific higher brain functions, such as memory, stress, anxiety and reward behavior. Copyright © 2014 John Wiley & Sons, Ltd.

fMRI of pain studies using laser-induced heat on skin with and without the loved one near the subject - a pilot study on 'love hurts'

NASA Astrophysics Data System (ADS)

Sofina, T.; Kamil, W. A.; Ahmad, A. H.

2014-11-01

The aims of this study are to image and investigate the areas of brain response to laser-induced heat pain, to analyse for any difference in the brain response when a subject is alone and when her loved one is present next to the MRI gantry. Pain stimuli was delivered using Th-YAG laser to four female subjects. Blood-Oxygenation-Level-Dependent (BOLD) fMRI experiment was performed using blocked design paradigm with five blocks of painful (P) stimuli and five blocks of non-painful (NP) stimuli arranged in pseudorandom order with an 18 seconds rest (R) between each stimulation phase. Brain images were obtained from 3T Philips Achieva MRI scanner using 32-channel SENSE head coil. A T1-weighted image (TR/TE/slice/FOV = 9ms/4ms/4mm slices/240×240mm) was obtained for verification of brain anatomical structures. An echo-planar-imaging sequence were used for the functional scans (TR/TE/slice/flip/FOV=2000ms/35ms/4mm slices/90°/220×220mm). fMRI data sets were analysed using SPM 8.0 involving preprocessing steps followed by t-contrast analysis for individuals and FFX analysis. In both with and without-loved-one conditions, neuronal responses were seen in the somatosensory gyrus, supramarginal gyrus, thalamus and insula regions, consistent with pain-related areas. FFX analysis showed that the presence of loved one produced more activation in the frontal and supramarginal gyrus during painful and non-painful stimulations compared to absence of a loved one. Brain response to pain is modulated by the presence of a loved one, causing more activation in the cognitive/emotional area i.e. 'love hurts'.

Pregnant serum induces neuroinflammation and seizure activity via TNFα.

PubMed

Cipolla, Marilyn J; Pusic, Aya D; Grinberg, Yelena Y; Chapman, Abbie C; Poynter, Matthew E; Kraig, Richard P

2012-04-01

Preeclampsia is a hypertensive disorder of pregnancy that affects many organs including the brain. Neurological complications occur during preeclampsia, the most serious of which is seizure known as eclampsia. Although preeclampsia can precede the eclamptic seizure, it often occurs during normal pregnancy, suggesting that processes associated with normal pregnancy can promote neuronal excitability. Here we investigated whether circulating inflammatory mediators that are elevated late in gestation when seizure also occurs are hyperexcitable to neuronal tissue. Evoked field potentials were measured in hippocampal slices in which control horse serum that slices are normally grown in, was replaced with serum from nonpregnant or late-pregnant Wistar rats for 48 h. We found that serum from pregnant, but not nonpregnant rats, caused hyperexcitability to hippocampal neurons and seizure activity that was abrogated by inhibition of tumor necrosis factor alpha (TNFα) signaling. Additionally, application of TNFα mimicked this increased excitability. Pregnant serum also caused morphological changes in microglia characteristic of activation, and increased TNFα mRNA expression that was not seen with exposure to nonpregnant serum. However, TNFα protein was not found to be elevated in pregnant serum itself, suggesting that other circulating factors during pregnancy caused activation of hippocampal slice cells to produce a TNFα-mediated increase in neuronal excitability. Lastly, although pregnant serum caused neuroinflammation and hyperexcitability of hippocampal slices, it did not increase blood-brain barrier permeability, nor were pregnant rats from which the serum was taken undergoing seizure. Thus, the BBB has an important role in protecting the brain from circulating neuroinflammatory mediators that are hyperexcitable to the brain during pregnancy. These studies provide novel insight into the underlying cause of eclampsia without elevated blood pressure and the protective role of the BBB that prevents exposure of the brain to hyperexcitable factors. Copyright © 2012 Elsevier Inc. All rights reserved.

Correcting for Strong Eddy Current Induced B0 Modulation Enables Two-Spoke RF Pulse Design with Parallel Transmission: Demonstration at 9.4T in the Human Brain

PubMed Central

Wu, Xiaoping; Adriany, Gregor; Ugurbil, Kamil; Van de Moortele, Pierre-Francois

2013-01-01

Successful implementation of homogeneous slice-selective RF excitation in the human brain at 9.4T using 16-channel parallel transmission (pTX) is demonstrated. A novel three-step pulse design method incorporating fast real-time measurement of eddy current induced B0 variations as well as correction of resulting phase errors during excitation is described. To demonstrate the utility of the proposed method, phantom and in-vivo experiments targeting a uniform excitation in an axial slice were conducted using two-spoke pTX pulses. Even with the pre-emphasis activated, eddy current induced B0 variations with peak-to-peak values greater than 4 kHz were observed on our system during the rapid switches of slice selective gradients. This large B0 variation, when not corrected, resulted in drastically degraded excitation fidelity with the coefficient of variation (CV) of the flip angle calculated for the region of interest being large (∼12% in the phantom and ∼35% in the brain). By comparison, excitation fidelity was effectively restored, and satisfactory flip angle uniformity was achieved when using the proposed method, with the CV value reduced to ∼3% in the phantom and ∼8% in the brain. Additionally, experimental results were in good agreement with the numerical predictions obtained from Bloch simulations. Slice-selective flip angle homogenization in the human brain at 9.4T using 16-channel 3D spoke pTX pulses is achievable despite of large eddy current induced excitation phase errors; correcting for the latter was critical in this success. PMID:24205098

SU-E-J-240: Development of a Novel 4D MRI Sequence for Real-Time Liver Tumor Tracking During Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhuang, L; Burmeister, J; Ye, Y

2015-06-15

Purpose: To develop a Novel 4D MRI Technique that is feasible for realtime liver tumor tracking during radiotherapy. Methods: A volunteer underwent an abdominal 2D fast EPI coronal scan on a 3.0T MRI scanner (Siemens Inc., Germany). An optimal set of parameters was determined based on image quality and scan time. A total of 23 slices were scanned to cover the whole liver in the test scan. For each scan position, the 2D images were retrospectively sorted into multiple phases based on breathing signal extracted from the images. Consequently the 2D slices with same phase numbers were stacked to formmore » one 3D image. Multiple phases of 3D images formed the 4D MRI sequence representing one breathing cycle. Results: The optimal set of scan parameters were: TR= 57ms, TE= 19ms, FOV read= 320mm and flip angle= 30°, which resulted in a total scan time of 14s for 200 frames (FMs) per slice and image resolution of (2.5mm,2.5mm,5.0mm) in three directions. Ten phases of 3D images were generated, each of which had 23 slices. Based on our test scan, only 100FMs were necessary for the phase sorting process which may lower the scan time to 7s/100FMs/slice. For example, only 5 slices/35s are necessary for a 4D MRI scan to cover liver tumor size ≤ 2cm leading to the possibility of tumor trajectory tracking every 35s during treatment. Conclusion: The novel 4D MRI technique we developed can reconstruct a 4D liver MRI sequence representing one breathing cycle (7s/ slice) without an external monitor. This technique can potentially be used for real-time liver tumor tracking during radiotherapy.« less

Reformatted images improve the detection rate of acute traumatic subdural hematomas on brain CT compared with axial images alone.

PubMed

Amrhein, Timothy J; Mostertz, William; Matheus, Maria Gisele; Maass-Bolles, Genevieve; Sharma, Komal; Collins, Heather R; Kranz, Peter G

2017-02-01

Subdural hematomas (SDHs) comprise a significant percentage of missed intracranial hemorrhage on axial brain CT. SDH detection rates could be improved with the addition of reformatted images. Though performed at some centers, the potential additional diagnostic sensitivity of reformatted images has not yet been investigated. The purpose of our study is to determine if the addition of coronal and sagittal reformatted images to an axial brain CT increases the sensitivity and specificity for detection of acute traumatic SDH. We retrospectively reviewed consecutive brain CTs acquired for acute trauma that contained new SDHs. An equivalent number of normal brain CTs served as control. Paired sets of images were created for each case: (1) axial images only ("axial only") and (2) axial, coronal, sagittal images ("reformat added"). Three readers interpreted both the axial only and companion reformat added for each case, separated by 1 month. Reading times and SDH detection rates were compared. One hundred SDH and 100 negative examinations were collected. Sensitivity and specificity for the axial-only scans were 75.7 and 94.3 %, respectively, compared with 88.3 and 98.3 % for reformat added. There was a 24.3 % false negative (missed SDH) rate with axial-only scans versus 11.7 % with reformat added (p = <0.001). Median reader interpretation times were longer with the addition of reformatted images (125 versus 89 s), but this difference was not significant (p = 0.23). The addition of coronal and sagittal images in trauma brain CT resulted in improved sensitivity and specificity as well as a reduction in SDH false negatives by greater than 50 %. Reformatted images substantially reduce the number of missed SDHs compared with axial images alone.

Proposed radiofrequency phased-array excitation scheme for homogenous and localized 7-Tesla whole-body imaging based on full-wave numerical simulations.

PubMed

Abraham, Roney; Ibrahim, Tamer S

2007-02-01

In this article, a radiofrequency (RF) excitation scheme for 7-Tesla (T) whole-body applications is derived and analyzed using the finite difference time domain (FDTD) method. Important features of the proposed excitation scheme and coil (a potential 7T whole-body transverse electromagnetic [TEM] resonator design), from both operational and electromagnetic perspectives, are discussed. The choice of the coil's operational mode is unconventional; instead of the typical "homogenous mode," we use a mode that provides a null field in the center of the coil at low-field applications. Using a 3D FDTD implementation of Maxwell's equations, we demonstrate that the whole-body 7T TEM coil (tuned to the aforementioned unconventional mode and excited in an optimized near-field, phased-array fashion) can potentially provide 1) homogenous whole-slice (demonstrated in three axial, sagittal, and coronal slices) and 2) 3D localized (demonstrated in the heart) excitations. As RF power was not considered as a part of the optimization in several cases, the significant improvements achieved by whole-slice RF excitation came at the cost of considerable increases in RF power requirements. Copyright (c) 2007 Wiley-Liss, Inc.

Tryptophan availability modulates serotonin release from rat hypothalamic slices

NASA Technical Reports Server (NTRS)

Schaechter, Judith D.; Wurtman, Richard J.

1989-01-01

The relationship between the tryptophan availability and serononin release from rat hypothalamus was investigated using a new in vitro technique for estimating rates at which endogenous serotonin is released spontaneously or upon electrical depolarization from hypothalamic slices superfused with a solution containing various amounts of tryptophan. It was found that the spontaneous, as well as electrically induced, release of serotonin from the brain slices exhibited a dose-dependent relationship with the tryptophan concentration of the superfusion medium.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jope, R.S.; Casebolt, T.L.; Johnson, G.V.

Cortical slices from rat brain were used to study carbachol-stimulated inositol phospholipid hydrolysis. Omission of calcium during incubation of slices with (/sup 3/H)inositol increased its incorporation into receptor-coupled phospholipids. Carbachol-stimulated hydrolysis of (/sup 3/H)inositol phospholipids in slices was dose-dependent, was affected by the concentrations of calcium and lithium present and resulted in the accumulation of mostly (/sup 3/H)inositol-1-phosphate. Incubation of slices with N-ethylmaleimide or a phorbol ester reduced the response to carbachol. Membranes prepared from cortical slices labeled with (/sup 3/H)inositol retained the receptor-stimulated inositol phospholipid hydrolysis reaction. The basal rate of inositol phospholipid hydrolysis was higher than in slicesmore » and addition of carbachol further stimulated the process. Addition of GTP stimulated inositol phospholipid hydrolysis, suggesting the presence of a guanine nucleotide-binding protein coupled to phospholipase C. Carbachol and GTP-stimulated inositol phospholipid hydrolysis in membranes was detectable following a 3 min assay period. In contrast to slices, increased levels of inositol bisphosphate and inositol trisphosphate were detected following incubation of membranes with carbachol. These results demonstrate that agonist-responsive receptors are present in cortical membranes, that the receptors may be coupled to phosphatidylinositol 4, 5-bisphosphate, rather than phosphatidylinositol, hydrolysis and that a guanine nucleotide-binding protein may mediate the coupling of receptor activation to inositol phospholipid hydrolysis in brain.« less

Hypo-and hyperthyroidism affect the ATP, ADP and AMP hydrolysis in rat hippocampal and cortical slices.

PubMed

Bruno, Alessandra Nejar; Diniz, Gabriela Placoná; Ricachenevsky, Felipe Klein; Pochmann, Daniela; Bonan, Carla Denise; Barreto-Chaves, Maria Luiza M; Sarkis, João José Freitas

2005-05-01

The presence of severe neurological symptoms in thyroid diseases has highlighted the importance of thyroid hormones in the normal functioning of the mature brain. Since, ATP is an important excitatory neurotransmitter and adenosine acts as a neuromodulatory structure inhibiting neurotransmitters release in the central nervous system (CNS), the ectonucleotidase cascade that hydrolyzes ATP to adenosine, is also involved in the control of brain functions. Thus, we investigated the influence of hyper-and hypothyroidism on the ATP, ADP and AMP hydrolysis in hippocampal and cortical slices from adult rats. Hyperthyroidism was induced by daily injections of l-thyroxine (T4) 25 microg/100 g body weight, for 14 days. Hypothyroidism was induced by thyroidectomy and methimazole (0.05%) added to their drinking water for 14 days. Hypothyroid rats were hormonally replaced by daily injections of T4 (5 microg/100 g body weight, i.p.) for 5 days. Hyperthyroidism significantly inhibited the ATP, ADP and AMP hydrolysis in hippocampal slices. In brain cortical slices, hyperthyroidism inhibited the AMP hydrolysis. In contrast, hypothyroidism increased the ATP, ADP and AMP hydrolysis in both hippocampal and cortical slices and these effects were reverted by T4 replacement. Furthermore, hypothyroidism increased the expression of NTPDase1 and 5'-nucleotidase, whereas hyperthyroidism decreased the expression of 5'-nucleotidase in hippocampus of adult rats. These findings demonstrate that thyroid disorders may influence the enzymes involved in the complete degradation of ATP to adenosine and possibly affects the responses mediated by adenine nucleotides in the CNS of adult rats.

Imaging Heat Shock Protein 90 (Hsp90) Activity in Hormone-Refractory Prostate Cancer

DTIC Science & Technology

2009-03-01

proteins. The quantitative PET imaging of EGFR expression with 64Cu- DOTA -cetuximab is successful for monitoring the early therapeutic response upon 17...activated DOTA ester to afford DOTA -TD) for 64Cu labeling. Mice bearing human glioma U87MG tumors were then subjected to microPET scans at various...time points post-injection (p.i.) of 64Cu- DOTA -TD. The coronal slices that contain the tumor are shown in Fig. 1. The uptake of 64Cu- DOTA -TD into U87MG

Changes in presynaptic release, but not reuptake, of bioamines induced by long-term antidepressant treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolzhenko, A.T.; Komissarov, I.V.

1986-10-01

This paper describes an investigation into the effect of long-term administration of antidepressants on neuronal uptake of NA and 5-HT and on their release, induced by electrical stimulation, in rat brain slices. The effects of the test substances on neuronal uptake of /sup 14/C-NA and /sup 3/H-5-HT by the slices was investigated. Values of IC/sub 50/ and EC/sub 2/ were found and compared in the experiments and control. The inhibitory effect of clonidine (10/sup -4/ M) and of 5-HT (10/sup -5/ M) on presynaptic release of /sup 14/C-NA and /sup 3/H-5-HT also was studied in brain slices from intact ratsmore » and rats treated for two weeks with antidepressants.« less

Xenon Protects against Blast-Induced Traumatic Brain Injury in an In Vitro Model.

PubMed

Campos-Pires, Rita; Koziakova, Mariia; Yonis, Amina; Pau, Ashni; Macdonald, Warren; Harris, Katie; Edge, Christopher J; Franks, Nicholas P; Mahoney, Peter F; Dickinson, Robert

2018-04-15

The aim of this study was to evaluate the neuroprotective efficacy of the inert gas xenon as a treatment for patients with blast-induced traumatic brain injury in an in vitro laboratory model. We developed a novel blast traumatic brain injury model using C57BL/6N mouse organotypic hippocampal brain-slice cultures exposed to a single shockwave, with the resulting injury quantified using propidium iodide fluorescence. A shock tube blast generator was used to simulate open field explosive blast shockwaves, modeled by the Friedlander waveform. Exposure to blast shockwave resulted in significant (p < 0.01) injury that increased with peak-overpressure and impulse of the shockwave, and which exhibited a secondary injury development up to 72 h after trauma. Blast-induced propidium iodide fluorescence overlapped with cleaved caspase-3 immunofluorescence, indicating that shock-wave-induced cell death involves apoptosis. Xenon (50% atm) applied 1 h after blast exposure reduced injury 24 h (p < 0.01), 48 h (p < 0.05), and 72 h (p < 0.001) later, compared with untreated control injury. Xenon-treated injured slices were not significantly different from uninjured sham slices at 24 h and 72 h. We demonstrate for the first time that xenon treatment after blast traumatic brain injury reduces initial injury and prevents subsequent injury development in vitro. Our findings support the idea that xenon may be a potential first-line treatment for those with blast-induced traumatic brain injury.

Improved cerebral energetics and ketone body metabolism in db/db mice

PubMed Central

Andersen, Jens V; Christensen, Sofie K; Nissen, Jakob D

2016-01-01

It is becoming evident that type 2 diabetes mellitus is affecting brain energy metabolism. The importance of alternative substrates for the brain in type 2 diabetes mellitus is poorly understood. The aim of this study was to investigate whether ketone bodies are relevant candidates to compensate for cerebral glucose hypometabolism and unravel the functionality of cerebral mitochondria in type 2 diabetes mellitus. Acutely isolated cerebral cortical and hippocampal slices of db/db mice were incubated in media containing [U-13C]glucose, [1,2-13C]acetate or [U-13C]β-hydroxybutyrate and tissue extracts were analysed by mass spectrometry. Oxygen consumption and ATP synthesis of brain mitochondria of db/db mice were assessed by Seahorse XFe96 and luciferin-luciferase assay, respectively. Glucose hypometabolism was observed for both cerebral cortical and hippocampal slices of db/db mice. Significant increased metabolism of [1,2-13C]acetate and [U-13C]β-hydroxybutyrate was observed for hippocampal slices of db/db mice. Furthermore, brain mitochondria of db/db mice exhibited elevated oxygen consumption and ATP synthesis rate. This study provides evidence of several changes in brain energy metabolism in type 2 diabetes mellitus. The increased hippocampal ketone body utilization and improved mitochondrial function in db/db mice, may act as adaptive mechanisms in order to maintain cerebral energetics during hampered glucose metabolism. PMID:28058963

White matter segmentation by estimating tissue optical attenuation from volumetric OCT massive histology of whole rodent brains

NASA Astrophysics Data System (ADS)

Lefebvre, Joël.; Castonguay, Alexandre; Lesage, Frédéric

2017-02-01

A whole rodent brain was imaged using an automated massive histology setup and an Optical Coherence Tomography (OCT) microscope. Thousands of OCT volumetric tiles were acquired, each covering a size of about 2.5x2.5x0.8 mm3 with a sampling resolution of 4.9x4.9x6.5 microns. This paper shows the techniques for reconstruction, attenuation compensation and segmentation of the sliced brains. The tile positions within the mosaic were evaluated using a displacement model of the motorized stage and pairwise coregistration. Volume blending was then performed by solving the 3D Laplace equation, and consecutive slices were assembled using the cross-correlation of their 2D image gradient. This reconstruction algorithm resulted in a 3D map of optical reflectivity for the whole brain at micrometric resolution. OCT tissue slices were then used to estimate the local attenuation coefficient based on a single scattering photon model. The attenuation map obtained exhibits a high contrast for all white matter fibres, regardless of their orientation. The tissue optical attenuation from the intrinsic OCT reflectivity contributes to better white matter tissue segmentation. The combined 3D maps of reflectivity and attenuation is a step toward the study of white matter at a microscopic scale for the whole brain in small animals.

BAD and KATP channels regulate neuron excitability and epileptiform activity.

PubMed

Martínez-François, Juan Ramón; Fernández-Agüera, María Carmen; Nathwani, Nidhi; Lahmann, Carolina; Burnham, Veronica L; Danial, Nika N; Yellen, Gary

2018-01-25

Brain metabolism can profoundly influence neuronal excitability. Mice with genetic deletion or alteration of Bad ( B CL-2 a gonist of cell d eath) exhibit altered brain-cell fuel metabolism, accompanied by resistance to acutely induced epileptic seizures; this seizure protection is mediated by ATP-sensitive potassium (K ATP ) channels. Here we investigated the effect of BAD manipulation on K ATP channel activity and excitability in acute brain slices. We found that BAD's influence on neuronal K ATP channels was cell-autonomous and directly affected dentate granule neuron (DGN) excitability. To investigate the role of neuronal K ATP channels in the anticonvulsant effects of BAD, we imaged calcium during picrotoxin-induced epileptiform activity in entorhinal-hippocampal slices. BAD knockout reduced epileptiform activity, and this effect was lost upon knockout or pharmacological inhibition of K ATP channels. Targeted BAD knockout in DGNs alone was sufficient for the antiseizure effect in slices, consistent with a 'dentate gate' function that is reinforced by increased K ATP channel activity. © 2018, Martínez-François et al.

The influence of brain iron and myelin on magnetic susceptibility and effective transverse relaxation - A biochemical and histological validation study.

PubMed

Hametner, Simon; Endmayr, Verena; Deistung, Andreas; Palmrich, Pilar; Prihoda, Max; Haimburger, Evelin; Menard, Christian; Feng, Xiang; Haider, Thomas; Leisser, Marianne; Köck, Ulrike; Kaider, Alexandra; Höftberger, Romana; Robinson, Simon; Reichenbach, Jürgen R; Lassmann, Hans; Traxler, Hannes; Trattnig, Siegfried; Grabner, Günther

2018-06-15

Quantitative susceptibility mapping (QSM) and effective transverse relaxation rate (R2*) mapping are both highly sensitive to variations in brain iron content. Clinical Magnetic Resonance Imaging (MRI) studies report changes of susceptibilities and relaxation rates in various neurological diseases which are often equated with changes in regional brain iron content. However, these mentioned metrics lack specificity for iron, since they are also influenced by the presence of myelin. In this study, we assessed the extent to which QSM and R2* reflect iron concentration as well as histological iron and myelin intensities. Six unfixed human post-mortem brains were imaged in situ with a 7 T MRI scanner. After formalin fixation, the brains were sliced axially and punched. 671 tissue punches were subjected to ferrozine iron quantification. Subsequently, brain slices were embedded in paraffin, and histological double-hemispheric axial brain slices were stained for Luxol fast blue (myelin) and diaminobenzidine (DAB)-enhanced Turnbull blue (iron). 3331 regions of interest (ROIs) were drawn on the histological stainings to assess myelin and iron intensities, which were compared with MRI data in corresponding ROIs. QSM more closely reflected quantitative ferrozine iron values (r = 0.755 vs. 0.738), whereas R2* correlated better with iron staining intensities (r = 0.619 vs. 0.445). Myelin intensities correlated negatively with QSM (r = -0.352), indicating a diamagnetic effect of myelin on susceptibility. Myelin intensities were higher in the thalamus than in the basal ganglia. A significant relationship was nonetheless observed between quantitative iron values and QSM, confirming the applicability of the latter in this brain region for iron quantification. Copyright © 2018. Published by Elsevier Inc.

Particle swarm optimization and its application in MEG source localization using single time sliced data

NASA Astrophysics Data System (ADS)

Lin, Juan; Liu, Chenglian; Guo, Yongning

2014-10-01

The estimation of neural active sources from the magnetoencephalography (MEG) data is a very critical issue for both clinical neurology and brain functions research. A widely accepted source-modeling technique for MEG involves calculating a set of equivalent current dipoles (ECDs). Depth in the brain is one of difficulties in MEG source localization. Particle swarm optimization(PSO) is widely used to solve various optimization problems. In this paper we discuss its ability and robustness to find the global optimum in different depths of the brain when using single equivalent current dipole (sECD) model and single time sliced data. The results show that PSO is an effective global optimization to MEG source localization when given one dipole in different depths.

Characterization and localization of /sup 3/H-arginine8-vasopressin binding to rat kidney and brain tissue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorsa, D.M.; Majumdar, L.A.; Petracca, F.M.

Anatomic, behavioral and pharmacologic evidence suggests that arginine8-vasopressin (AVP) serves as a CNS neurotransmitter or neuromodulator. AVP binding to membrane and tissue slice preparations from brain and kidney was characterized, and the anatomical distribution of these binding sites was examined. Conditions for the binding assay were optimized using kidney medullary tissue. Binding of /sup 3/H-AVP (S.A. . 30-51 Ci/mmol, NEN) to brain and kidney membranes and tissue slices was saturable, temperature dependent, linearly related to protein concentration (or number of tissue slices), reversible, and specific since the ability of cold AVP to displace /sup 3/H-AVP from binding was greater thanmore » oxytocin and other related peptide fragments. Autoradiographic localization of /sup 3/H-AVP binding was restricted to kidney medullary tissue. In brain tissue, /sup 3/H-AVP binding was found to occur in concentrated foci. Brainstem areas such as the nucleus tractus solitarius (NTS) showed a high density of AVP binding sites. Since local injections of AVP into the NTS have been shown to influence blood pressure, the present study presents the first anatomical evidence for the presence of AVP specific binding sites which might mediate this effect.« less

Effects of endogenous pyrogen and prostaglandin E2 on hypothalamic neurons in rat brain slices.

PubMed

Watanabe, T; Morimoto, A; Murakami, N

1987-06-01

We investigated the effects of endogenous pyrogen and prostaglandin E2 (PGE2) on the preoptic and anterior hypothalamic (POAH) neurons using brain slice preparations from the rat. Partially purified endogenous pyrogen did not change the activities of most of the neurons in the POAH region when applied locally through a micropipette attached to the recording electrode in proximity to the neurons. This indicates that partially purified endogenous pyrogen does not act directly on the neuronal activity in the POAH region. The partially purified endogenous pyrogen, applied into a culture chamber containing a brain slice, facilitated the activities in 24% of the total neurons tested, regardless of the thermal specificity of the neurons. Moreover, PGE2 added to the culture chamber facilitated 48% of the warm-responsive, 33% of the cold-responsive, and 29% of the thermally insensitive neurons. The direction of change in neuronal activity induced by partially purified endogenous pyrogen appears to be almost the same as that induced by PGE2 when these substances were applied by perfusion to the same neuron in the culture chamber. These results suggest that partially purified pyrogen applied to the perfusate of the culture chamber stimulates some constituents of brain tissue to synthesize and release prostaglandin, which in turn affects the neuronal activity of the POAH region.

GTP effects in rat brain slices support the non-interconvertability of M/sub 1/ and M/sub 2/ muscarinic acetylcholine receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spencer, D.G. Jr.; Horvath, E.; Traber, J.

GTP (guanosine-5'-triphosphate) markedly reduced high-affinity /sup 3/H-oxotremorine-M binding to M/sub 2/ receptors on brain slices in autoradiographic experiments while /sup 3/H-pirenzepine binding to M/sub 1/ receptors was largely unaffected. The distribution of M/sub 1/ receptors so labelled was also not altered by GTP to include former M/sub 2/-rich regions, thus indicating that GTP could not, by itself, interconvert high agonist-affinity M/sub 2/ receptors to M/sub 1/ receptors. 18 references, 1 figure.

Super-resolution reconstruction in frequency, image, and wavelet domains to reduce through-plane partial voluming in MRI.

PubMed

Gholipour, Ali; Afacan, Onur; Aganj, Iman; Scherrer, Benoit; Prabhu, Sanjay P; Sahin, Mustafa; Warfield, Simon K

2015-12-01

To compare and evaluate the use of super-resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through-plane partial voluming effects in magnetic resonance imaging. The reconstruction of an isotropic high-resolution image from multiple thick-slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick-slice T2-weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high-resolution scan using peak signal-to-noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) of image intensity profiles. The application of super-resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through-plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities. Quantitative evaluation results show improvements in all evaluation metrics through super-resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image-domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in-plane and out-of-plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in resampled out-of-plane views consistently showed the superiority of SRR compared to original axial and coronal image acquisitions. Thick-slice 2D T2-weighted MRI scans are part of many routine clinical protocols due to their high signal-to-noise ratio, but are often severely affected by through-plane partial voluming effects. This study shows that while radiologic assessment is performed in 2D on thick-slice scans, super-resolution MRI reconstruction techniques can be used to fuse those scans to generate a high-resolution image with reduced partial voluming for improved postacquisition processing. Qualitative and quantitative evaluation showed the efficacy of all SRR techniques with the best results obtained from SRR in the image domain. The limitations of SRR techniques are uncertainties in modeling the slice profile, density compensation, quantization in resampling, and uncompensated motion between scans.

Adenovirus-mediated gene delivery to cells of the magnocellular hypothalamo-neurohypophyseal system

NASA Technical Reports Server (NTRS)

Vasquez, E. C.; Beltz, T. G.; Haskell, R. E.; Johnson, R. F.; Meyrelles, S. S.; Davidson, B. L.; Johnson, A. K.

2001-01-01

The objective of the present study was to define the optimum conditions for using replication-defective adenovirus (Ad) to transfer the gene for the green fluorescent protein (GFP) to the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei and cells of the neurohypophysis (NH). As indicated by characterizing cell survival over 15 days in culture and in electrophysiological whole cell patch-clamp studies, viral concentrations up to 2 x 10(7) pfu/coverslip did not affect viability of transfected PVN and NH cultured cells from preweanling rats. At 2 x 10(7) pfu, GFP gene expression was higher (40% of GFP-positive cells) and more sustained (up to 15 days). Using a stereotaxic approach in adult rats, we were able to directly transduce the PVN, SON, and NH and visualize gene expression in coronal brain slices and in the pituitary 4 days after injection of Ad. In animals receiving NH injections of Ad, the virus was retrogradely transported to PVN and SON neurons as indicated by the appearance of GFP-positive neurons in cultures of dissociated cells from those brain nuclei and by polymerase chain reaction and Western blot analyses of PVN and SON tissues. Adenoviral concentrations of up to 8 x 10(6) pfu injected into the NH did not affect cell viability and did not cause inflammatory responses. Adenoviral injection into the pituitary enabled the selective delivery of genes to the soma of magnocellular neurons. The experimental approaches described here provide potentially useful strategies for the treatment of disordered expression of the hormones vasopressin or oxytocin. Copyright 2000 Academic Press.

Residual dentin thickness in mandibular premolars prepared with gates glidden and ParaPost drills.

PubMed

Pilo, R; Tamse, A

2000-06-01

The main factor that determines the prognosis of restored pulpless teeth is preservation of sound dentin. This study evaluated the residual dentinal thickness (RDT) of mandibular premolars after preparation of post space with Gates Glidden and ParaPost drills. Twelve extracted single canal mandibular premolars were embedded in clear polyester resin to the cementoenamel junction (CEJ) in a muffle device. Three horizontal sections were made 1, 3, and 5 mm apical to the CEJ. Mesiodistal (MD) and faciolingual (FL) axes were carefully marked and the RDT was measured for each slice. Each tooth slice was reassembled in the muffle device with orientation pins, then secured with stabilizing pins. This procedure was repeated after enlarging the root canal to K-40 file and preparing the coronal root canal space with Gates Glidden drills and ParaPost drills Nos. 3, 4, and 5. Residual dentinal thickness in a MD direction was 3.77 +/- 0.51 mm in the unprepared upper slice and 2.23 +/- 0.31 mm in the No. 5 ParaPost drill prepared lower slice, for a difference of 41%. The corresponding values for the FL direction were 4.35 +/- 0.51 mm and 4.08 +/- 0.46 mm, respectively (6%). The average dentinal thickness 5 mm below the CEJ in the mesial and distal directions after post space preparation approached the accepted minimal 1 mm. A conservative approach to post space preparation was advocated.

In vivo single-shot three-dimensionally localized multiple quantum spectroscopy of GABA in the human brain with improved spectral selectivity

NASA Astrophysics Data System (ADS)

Choi, In-Young; Lee, Sang-Pil; Shen, Jun

2005-01-01

A single-shot multiple quantum filtering method is developed that uses two double-band frequency selective pulses for enhanced spectral selectivity in combination with a slice-selective 90°, a slice-selective universal rotator 90°, and a spectral-spatial pulse composed of two slice-selective universal rotator 45° pulses for single-shot three-dimensional localization. The use of this selective multiple quantum filtering method for C3 and C4 methylene protons of GABA resulted in improved spectral selectivity for GABA and effective suppression of overlapping signals such as creatine and glutathione in each single scan, providing reliable measurements of the GABA doublet in all subjects. The concentration of GABA was measured to be 0.7 ± 0.2 μmol/g (means ± SD, n = 15) in the fronto-parietal region of the human brain in vivo.

The Effects of Magnetic Exposure on the Nervous System: A study on the effects of low-strength low-frequency magnetic fields on neurotransmitter exocytosis and cell viability through ionic cyclotron resonance frequency

NASA Astrophysics Data System (ADS)

Saveriades, George

This PhD dissertation focuses on the study of the effects of magnetic exposure on biological systems using amperometry techniques and viability assays. In our prior work based on the cyclotron resonance model, chromaffin cells in physiological saline and Ca2+-free media were exposed for 5 minutes to a 2.7 muT magnetic field, with frequency sweeps going from 30-60 Hz (targeting several ions involved in exocytosis) and 44-48 Hz (targeting specifically Ca2+ ions), with noticeable effects on exocytosis. The present study extended the work on chromaffin cells by covering frequency sweeps for different ions, manipulating the time of exposure and the strength of the magnetic field. Furthermore, amperometry was conducted on acute coronal brain slices, to demonstrate that the recorded effects could be measured on neuronal tissue. The viability of chromaffin cells and primary neuronal cultures exposed to magnetic fields was also addressed. The results demonstrate that cellular exocytosis is sensitive to the frequency of the magnetic field it is exposed to, the strength of the magnetic field and the duration of exposure. No significant effects were established with regards to the viability of the cells exposed to magnetic fields.

Push-out bond strengths of fiber-reinforced composite posts with various resin cements according to the root level

PubMed Central

Chang, Hoon-Sang; Noh, Young-Sin; Lee, Yoon; Min, Kyung-San

2013-01-01

PURPOSE The aim of this study was to determine whether the push-out bond strengths between the radicular dentin and fiber reinforced-composite (FRC) posts with various resin cements decreased or not, according to the coronal, middle or apical level of the root. MATERIALS AND METHODS FRC posts were cemented with one of five resin cement groups (RelyX Unicem: Uni, Contax with activator & LuxaCore-Dual: LuA, Contax & LuxaCore-Dual: Lu, Panavia F 2.0: PA, Super-Bond C&B: SB) into extracted human mandibular premolars. The roots were sliced into discs at the coronal, middle and apical levels. Push-out bond strength tests were performed with a universal testing machine at a crosshead speed of 0.5 mm/min, and the failure aspect was analyzed. RESULTS There were no significant differences (P>.05) in the bond strengths of the different resin cements at the coronal level, but there were significant differences in the bond strengths at the middle and apical levels (P<.05). Only the Uni and LuA cements did not show any significant decrease in their bond strengths at all the root levels (P>.05); all other groups had a significant decrease in bond strength at the middle or apical level (P<.05). The failure aspect was dominantly cohesive at the coronal level of all resin cements (P<.05), whereas it was dominantly adhesive at the apical level. CONCLUSION All resin cement groups showed decreases in bond strengths at the middle or apical level except LuA and Uni. PMID:24049569

Determination of regional brain temperature using proton magnetic resonance spectroscopy to assess brain-body temperature differences in healthy human subjects.

PubMed

Childs, Charmaine; Hiltunen, Yrjö; Vidyasagar, Rishma; Kauppinen, Risto A

2007-01-01

Proton magnetic resonance spectroscopy ((1)H MRS) was used to determine brain temperature in healthy volunteers. Partially water-suppressed (1)H MRS data sets were acquired at 3T from four different gray matter (GM)/white matter (WM) volumes. Brain temperatures were determined from the chemical-shift difference between the CH(3) of N-acetyl aspartate (NAA) at 2.01 ppm and water. Brain temperatures in (1)H MRS voxels of 2 x 2 x 2 cm(3) showed no substantial heterogeneity. The volume-averaged temperature from single-voxel spectroscopy was compared with body temperatures obtained from the oral cavity, tympanum, and temporal artery regions. The mean brain parenchyma temperature was 0.5 degrees C cooler than readings obtained from three extra-brain sites (P < 0.01). (1)H MRS imaging (MRSI) data were acquired from a slice encompassing the single-voxel volumes to assess the ability of spectroscopic imaging to determine regional brain temperature within the imaging slice. Brain temperature away from the center of the brain determined by MRSI differed from that obtained by single-voxel MRS in the same brain region, possibly due to a poor line width (LW) in MRSI. The data are discussed in the light of proposed brain-body temperature gradients and the use of (1)H MRSI to monitor brain temperature in pathologies, such as brain trauma.

A Unified Approach to Diffusion Direction Sensitive Slice Registration and 3-D DTI Reconstruction From Moving Fetal Brain Anatomy

PubMed Central

Fogtmann, Mads; Seshamani, Sharmishtaa; Kroenke, Christopher; Cheng, Xi; Chapman, Teresa; Wilm, Jakob; Rousseau, François

2014-01-01

This paper presents an approach to 3-D diffusion tensor image (DTI) reconstruction from multi-slice diffusion weighted (DW) magnetic resonance imaging acquisitions of the moving fetal brain. Motion scatters the slice measurements in the spatial and spherical diffusion domain with respect to the underlying anatomy. Previous image registration techniques have been described to estimate the between slice fetal head motion, allowing the reconstruction of 3-D a diffusion estimate on a regular grid using interpolation. We propose Approach to Unified Diffusion Sensitive Slice Alignment and Reconstruction (AUDiSSAR) that explicitly formulates a process for diffusion direction sensitive DW-slice-to-DTI-volume alignment. This also incorporates image resolution modeling to iteratively deconvolve the effects of the imaging point spread function using the multiple views provided by thick slices acquired in different anatomical planes. The algorithm is implemented using a multi-resolution iterative scheme and multiple real and synthetic data are used to evaluate the performance of the technique. An accuracy experiment using synthetically created motion data of an adult head and a experiment using synthetic motion added to sedated fetal monkey dataset show a significant improvement in motion-trajectory estimation compared to a state-of-the-art approaches. The performance of the method is then evaluated on challenging but clinically typical in utero fetal scans of four different human cases, showing improved rendition of cortical anatomy and extraction of white matter tracts. While the experimental work focuses on DTI reconstruction (second-order tensor model), the proposed reconstruction framework can employ any 5-D diffusion volume model that can be represented by the spatial parameterizations of an orientation distribution function. PMID:24108711

Xenon Protects against Blast-Induced Traumatic Brain Injury in an In Vitro Model

PubMed Central

Campos-Pires, Rita; Koziakova, Mariia; Yonis, Amina; Pau, Ashni; Macdonald, Warren; Harris, Katie; Edge, Christopher J.; Franks, Nicholas P.; Mahoney, Peter F.

2018-01-01

Abstract The aim of this study was to evaluate the neuroprotective efficacy of the inert gas xenon as a treatment for patients with blast-induced traumatic brain injury in an in vitro laboratory model. We developed a novel blast traumatic brain injury model using C57BL/6N mouse organotypic hippocampal brain-slice cultures exposed to a single shockwave, with the resulting injury quantified using propidium iodide fluorescence. A shock tube blast generator was used to simulate open field explosive blast shockwaves, modeled by the Friedlander waveform. Exposure to blast shockwave resulted in significant (p < 0.01) injury that increased with peak-overpressure and impulse of the shockwave, and which exhibited a secondary injury development up to 72 h after trauma. Blast-induced propidium iodide fluorescence overlapped with cleaved caspase-3 immunofluorescence, indicating that shock-wave–induced cell death involves apoptosis. Xenon (50% atm) applied 1 h after blast exposure reduced injury 24 h (p < 0.01), 48 h (p < 0.05), and 72 h (p < 0.001) later, compared with untreated control injury. Xenon-treated injured slices were not significantly different from uninjured sham slices at 24 h and 72 h. We demonstrate for the first time that xenon treatment after blast traumatic brain injury reduces initial injury and prevents subsequent injury development in vitro. Our findings support the idea that xenon may be a potential first-line treatment for those with blast-induced traumatic brain injury. PMID:29285980

Long-term exposure to nicotine markedly reduces kynurenic acid in rat brain - In vitro and ex vivo evidence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zielinska, Elzbieta; Kuc, Damian; Zgrajka, Wojciech

Kynurenic acid (KYNA) is a recognized broad-spectrum antagonist of excitatory amino acid receptors with a particularly high affinity for the glycine co-agonist site of the N-methyl-D-aspartate (NMDA) receptor complex. KYNA is also a putative endogenous neuroprotectant. Recent studies show that KYNA strongly blocks {alpha}7 subtype of nicotinic acetylcholine receptors (nAChRs). The present studies were aimed at assessing effects of acute and chronic nicotine exposure on KYNA production in rat brain slices in vitro and ex vivo. In brain slices, nicotine significantly increased KYNA formation at 10 mM but not at 1 or 5 mM. Different nAChR antagonists (dihydro-{beta}-erythroidine, methyllycaconitine andmore » mecamylamine) failed to block the influence exerted by nicotine on KYNA synthesis in cortical slices in vitro. Effects of acute (1 mg/kg, i.p.), subchronic (10-day) and chronic (30-day) administration of nicotine in drinking water (100 {mu}g/ml) on KYNA brain content were evaluated ex vivo. Acute treatment with nicotine (1 mg/kg i.p.) did not affect KYNA level in rat brain. The subchronic exposure to nicotine in drinking water significantly increased KYNA by 43%, while chronic exposure to nicotine resulted in a reduction in KYNA by 47%. Co-administration of mecamylamine with nicotine in drinking water for 30 days reversed the effect exerted by nicotine on KYNA concentration in the cerebral cortex. The present results provide evidence for the hypothesis of reciprocal interaction between the nicotinic cholinergic system and the kynurenine pathway in the brain.« less

High-resolution whole-brain diffusion MRI at 7T using radiofrequency parallel transmission.

PubMed

Wu, Xiaoping; Auerbach, Edward J; Vu, An T; Moeller, Steen; Lenglet, Christophe; Schmitter, Sebastian; Van de Moortele, Pierre-François; Yacoub, Essa; Uğurbil, Kâmil

2018-03-30

Investigating the utility of RF parallel transmission (pTx) for Human Connectome Project (HCP)-style whole-brain diffusion MRI (dMRI) data at 7 Tesla (7T). Healthy subjects were scanned in pTx and single-transmit (1Tx) modes. Multiband (MB), single-spoke pTx pulses were designed to image sagittal slices. HCP-style dMRI data (i.e., 1.05-mm resolutions, MB2, b-values = 1000/2000 s/mm 2 , 286 images and 40-min scan) and data with higher accelerations (MB3 and MB4) were acquired with pTx. pTx significantly improved flip-angle detected signal uniformity across the brain, yielding ∼19% increase in temporal SNR (tSNR) averaged over the brain relative to 1Tx. This allowed significantly enhanced estimation of multiple fiber orientations (with ∼21% decrease in dispersion) in HCP-style 7T dMRI datasets. Additionally, pTx pulses achieved substantially lower power deposition, permitting higher accelerations, enabling collection of the same data in 2/3 and 1/2 the scan time or of more data in the same scan time. pTx provides a solution to two major limitations for slice-accelerated high-resolution whole-brain dMRI at 7T; it improves flip-angle uniformity, and enables higher slice acceleration relative to current state-of-the-art. As such, pTx provides significant advantages for rapid acquisition of high-quality, high-resolution truly whole-brain dMRI data. © 2018 International Society for Magnetic Resonance in Medicine.

Mesenchymal stem cells support neuronal fiber growth in an organotypic brain slice co-culture model.

PubMed

Sygnecka, Katja; Heider, Andreas; Scherf, Nico; Alt, Rüdiger; Franke, Heike; Heine, Claudia

2015-04-01

Mesenchymal stem cells (MSCs) have been identified as promising candidates for neuroregenerative cell therapies. However, the impact of different isolation procedures on the functional and regenerative characteristics of MSC populations has not been studied thoroughly. To quantify these differences, we directly compared classically isolated bulk bone marrow-derived MSCs (bulk BM-MSCs) to the subpopulation Sca-1(+)Lin(-)CD45(-)-derived MSCs(-) (SL45-MSCs), isolated by fluorescence-activated cell sorting from bulk BM-cell suspensions. Both populations were analyzed with respect to functional readouts, that are, frequency of fibroblast colony forming units (CFU-f), general morphology, and expression of stem cell markers. The SL45-MSC population is characterized by greater morphological homogeneity, higher CFU-f frequency, and significantly increased nestin expression compared with bulk BM-MSCs. We further quantified the potential of both cell populations to enhance neuronal fiber growth, using an ex vivo model of organotypic brain slice co-cultures of the mesocortical dopaminergic projection system. The MSC populations were cultivated underneath the slice co-cultures without direct contact using a transwell system. After cultivation, the fiber density in the border region between the two brain slices was quantified. While both populations significantly enhanced fiber outgrowth as compared with controls, purified SL45-MSCs stimulated fiber growth to a larger degree. Subsequently, we analyzed the expression of different growth factors in both cell populations. The results show a significantly higher expression of brain-derived neurotrophic factor (BDNF) and basic fibroblast growth factor in the SL45-MSCs population. Altogether, we conclude that MSC preparations enriched for primary MSCs promote neuronal regeneration and axonal regrowth, more effectively than bulk BM-MSCs, an effect that may be mediated by a higher BDNF secretion.

Genetically Targeted All-Optical Electrophysiology with a Transgenic Cre-Dependent Optopatch Mouse

PubMed Central

Lou, Shan; Adam, Yoav; Weinstein, Eli N.; Williams, Erika; Williams, Katherine; Parot, Vicente; Kavokine, Nikita; Liberles, Stephen; Madisen, Linda; Zeng, Hongkui

2016-01-01

Recent advances in optogenetics have enabled simultaneous optical perturbation and optical readout of membrane potential in diverse cell types. Here, we develop and characterize a Cre-dependent transgenic Optopatch2 mouse line that we call Floxopatch. The animals expressed a blue-shifted channelrhodopsin, CheRiff, and a near infrared Archaerhodopsin-derived voltage indicator, QuasAr2, via targeted knock-in at the rosa26 locus. In Optopatch-expressing animals, we tested for overall health, genetically targeted expression, and function of the optogenetic components. In offspring of Floxopatch mice crossed with a variety of Cre driver lines, we observed spontaneous and optically evoked activity in vitro in acute brain slices and in vivo in somatosensory ganglia. Cell-type-specific expression allowed classification and characterization of neuronal subtypes based on their firing patterns. The Floxopatch mouse line is a useful tool for fast and sensitive characterization of neural activity in genetically specified cell types in intact tissue. SIGNIFICANCE STATEMENT Optical recordings of neural activity offer the promise of rapid and spatially resolved mapping of neural function. Calcium imaging has been widely applied in this mode, but is insensitive to the details of action potential waveforms and subthreshold events. Simultaneous optical perturbation and optical readout of single-cell electrical activity (“Optopatch”) has been demonstrated in cultured neurons and in organotypic brain slices, but not in acute brain slices or in vivo. Here, we describe a transgenic mouse in which expression of Optopatch constructs is controlled by the Cre-recombinase enzyme. This animal enables fast and robust optical measurements of single-cell electrical excitability in acute brain slices and in somatosensory ganglia in vivo, opening the door to rapid optical mapping of neuronal excitability. PMID:27798186

1975 Memorial Award Paper. Image generation and display techniques for CT scan data. Thin transverse and reconstructed coronal and sagittal planes.

PubMed

Glenn, W V; Johnston, R J; Morton, P E; Dwyer, S J

1975-01-01

The various limitations to computerized axial tomographic (CT) interpretation are due in part to the 8-13 mm standard tissue plane thickness and in part to the absence of alternative planes of view, such as coronal or sagittal images. This paper describes a method for gathering multiple overlapped 8 mm transverse sections, subjecting these data to a deconvolution process, and then displaying thin (1 mm) transverse as well as reconstructed coronal and sagittal CT images. Verification of the deconvolution technique with phantom experiments is described. Application of the phantom results to human post mortem CT scan data illustrates this method's faithful reconstruction of coronal and sagittal tissue densities when correlated with actual specimen photographs of a sectioned brain. A special CT procedure, limited basal overlap scanning, is proposed for use on current first generation CT scanners without hardware modification.

Noninvasive quantification of left ventricular mass by cardiac magnetic resonance imaging: Development of the method and experimental validation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maddahi, J.; Crues, J.; Berman, D.S.

1985-05-01

Determination of left ventricular myocardial (LV) mass may aid evaluation of hypertrophic cardiomyopathies as well as percent viable myocardium in ischemic heart disease. The validity of cardiac NMR for determination of LV mass was evaluated in 9 dogs using a superconducting magnet operating at 0.35 Tesla. In-vivo gated spin echo pulsing sequences were used obtaining 0.7 cm thick slices of the heart, spaced by 1 cm, in three orthogonal planes. After sacrifice, the nonbeating hearts were imaged in-situ without gating. On each NMR slice, the LV surface area was planimetered and multiplied by slice spacing (1) and myocardial specific gravitymore » (1.05) to obtain slice mass. For total LV mass, slice masses were added on coronal (Method (Meth) 1), transaxial (Meth 2), and sagittal (Meth 3) planes. Mass of the LV portions subject to partial volume effect were derived from an orthogonal plane. Excised LV weight ranged from 27 to 134 grams. The intra- and inter-observer agreement for planimetry of the NMR slices was high (r=.99 and r=.97, respectively). For in-situ imaging, r values of all methods were high (r=.99, .99, and .98); however, the slope and intercept of the regression line were closes to the line of identity with Meth 1 (y=0.94x+0.52). For in-vivo beating heart images, Meth 1 also had the best results (r=.99, y= 0.99x+8.3). Failure to correct for partial volume effect resulted in underestimation of in-situ and in-vivo LV masses as indicated by slope of <1 (r=,.98, y=0.77x+3.9; r=.98, y= 0.88x+0.98, respectively, Meth 1). Thus, cardiac NMR is a reproducible and accurate method for noninvasive determination of LV myocardial mass.« less

Chronic Ethanol Consumption Profoundly Alters Regional Brain Ceramide and Sphingomyelin Content in Rodents

PubMed Central

2015-01-01

Ceramides (CER) are involved in alcohol-induced neuroinflammation. In a mouse model of chronic alcohol exposure, 16 CER and 18 sphingomyelin (SM) concentrations from whole brain lipid extracts were measured using electrospray mass spectrometry. All 18 CER concentrations in alcohol exposed adults increased significantly (range: 25–607%); in juveniles, 6 CER decreased (range: −9 to −37%). In contrast, only three SM decreased in adult and one increased significantly in juvenile. Next, regional identification at 50 μm spatial resolution from coronal sections was obtained with matrix implanted laser desorption/ionization mass spectrometry imaging (MILDI-MSI) by implanting silver nanoparticulate matrices followed by focused laser desorption. Most of the CER and SM quantified in whole brain extracts were detected in MILDI images. Coronal sections from three brain levels show qualitative regional changes in CER-SM ion intensities, as a function of group and brain region, in cortex, striatum, accumbens, habenula, and hippocampus. Highly correlated changes in certain white matter CER-SM pairs occur in regions across all groups, including the hippocampus and the lateral (but not medial) cerebellar cortex of adult mice. Our data provide the first microscale MS evidence of regional lipid intensity variations induced by alcohol. PMID:25387107

Neural Plasticity and Neurorehabilitation Following Traumatic Brain Injury

DTIC Science & Technology

2010-10-01

for sectioning and staining . To date, the brains have been sectioned and one set stained for Nissl . Using the Nissl stained sections, Dorothy...all behavioral data. • Brains have been harvested and sent to Dr. Jones’ lab • Dr. Jones’ lab has sliced the brains and stained one set with Nissl ...remaining sets of brain sections are currently being stained with markers of plasticity using immunohistochemistry. We have completed immunohistochemical

Stimulation of brain glucose uptake by cannabinoid CB2 receptors and its therapeutic potential in Alzheimer's disease.

PubMed

Köfalvi, Attila; Lemos, Cristina; Martín-Moreno, Ana M; Pinheiro, Bárbara S; García-García, Luis; Pozo, Miguel A; Valério-Fernandes, Ângela; Beleza, Rui O; Agostinho, Paula; Rodrigues, Ricardo J; Pasquaré, Susana J; Cunha, Rodrigo A; de Ceballos, María L

2016-11-01

Cannabinoid CB2 receptors (CB2Rs) are emerging as important therapeutic targets in brain disorders that typically involve neurometabolic alterations. We here addressed the possible role of CB2Rs in the regulation of glucose uptake in the mouse brain. To that aim, we have undertaken 1) measurement of (3)H-deoxyglucose uptake in cultured cortical astrocytes and neurons and in acute hippocampal slices; 2) real-time visualization of fluorescently labeled deoxyglucose uptake in superfused hippocampal slices; and 3) in vivo PET imaging of cerebral (18)F-fluorodeoxyglucose uptake. We now show that both selective (JWH133 and GP1a) as well as non-selective (WIN55212-2) CB2R agonists, but not the CB1R-selective agonist, ACEA, stimulate glucose uptake, in a manner that is sensitive to the CB2R-selective antagonist, AM630. Glucose uptake is stimulated in astrocytes and neurons in culture, in acute hippocampal slices, in different brain areas of young adult male C57Bl/6j and CD-1 mice, as well as in middle-aged C57Bl/6j mice. Among the endocannabinoid metabolizing enzymes, the selective inhibition of COX-2, rather than that of FAAH, MAGL or α,βDH6/12, also stimulates the uptake of glucose in hippocampal slices of middle-aged mice, an effect that was again prevented by AM630. However, we found the levels of the endocannabinoid, anandamide reduced in the hippocampus of TgAPP-2576 mice (a model of β-amyloidosis), and likely as a consequence, COX-2 inhibition failed to stimulate glucose uptake in these mice. Together, these results reveal a novel general glucoregulatory role for CB2Rs in the brain, raising therapeutic interest in CB2R agonists as nootropic agents. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

A Novel Application for the Cavalieri Principle: A Stereological and Methodological Study

PubMed Central

Altunkaynak, Berrin Zuhal; Altunkaynak, Eyup; Unal, Deniz; Unal, Bunyamin

2009-01-01

Objective The Cavalieri principle was applied to consecutive pathology sections that were photographed at the same magnification and used to estimate tissue volumes via superimposing a point counting grid on these images. The goal of this study was to perform the Cavalieri method quickly and practically. Materials and Methods In this study, 10 adult female Sprague Dawley rats were used. Brain tissue was removed and sampled both systematically and randomly. Brain volumes were estimated using two different methods. First, all brain slices were scanned with an HP ScanJet 3400C scanner, and their images were shown on a PC monitor. Brain volume was then calculated based on these images. Second, all brain slices were photographed in 10× magnification with a microscope camera, and brain volumes were estimated based on these micrographs. Results There was no statistically significant difference between the volume measurements of the two techniques (P>0.05; Paired Samples t Test). Conclusion This study demonstrates that personal computer scanning of serial tissue sections allows for easy and reliable volume determination based on the Cavalieri method. PMID:25610077

A novel application for the cavalieri principle: a stereological and methodological study.

PubMed

Altunkaynak, Berrin Zuhal; Altunkaynak, Eyup; Unal, Deniz; Unal, Bunyamin

2009-08-01

The Cavalieri principle was applied to consecutive pathology sections that were photographed at the same magnification and used to estimate tissue volumes via superimposing a point counting grid on these images. The goal of this study was to perform the Cavalieri method quickly and practically. In this study, 10 adult female Sprague Dawley rats were used. Brain tissue was removed and sampled both systematically and randomly. Brain volumes were estimated using two different methods. First, all brain slices were scanned with an HP ScanJet 3400C scanner, and their images were shown on a PC monitor. Brain volume was then calculated based on these images. Second, all brain slices were photographed in 10× magnification with a microscope camera, and brain volumes were estimated based on these micrographs. There was no statistically significant difference between the volume measurements of the two techniques (P>0.05; Paired Samples t Test). This study demonstrates that personal computer scanning of serial tissue sections allows for easy and reliable volume determination based on the Cavalieri method.

Monitoring gap junctional communication in astrocytes from acute adult mouse brain slices using the gap-FRAP technique.

PubMed

Yi, Chenju; Teillon, Jérémy; Koulakoff, Annette; Berry, Hugues; Giaume, Christian

2018-06-01

Intercellular communication through gap junction channels plays a key role in cellular homeostasis and in synchronizing physiological functions, a feature that is modified in number of pathological situations. In the brain, astrocytes are the cell population that expresses the highest amount of gap junction proteins, named connexins. Several techniques have been used to assess the level of gap junctional communication in astrocytes, but so far they remain very difficult to apply in adult brain tissue. Here, using specific loading of astrocytes with sulforhodamine 101, we adapted the gap-FRAP (Fluorescence Recovery After Photobleaching) to acute hippocampal slices from 9 month-old adult mice. We show that gap junctional communication monitored in astrocytes with this technique was inhibited either by pharmacological treatment with a gap junctional blocker or in mice lacking the two main astroglial connexins, while a partial inhibition was measured when only one connexin was knocked-out. We validate this approach using a mathematical model of sulforhodamine 101 diffusion in an elementary astroglial network and a quantitative analysis of the exponential fits to the fluorescence recovery curves. Consequently, we consider that the adaptation of the gap-FRAP technique to acute brain slices from adult mice provides an easy going and valuable approach that allows overpassing this age-dependent obstacle and will facilitate the investigation of gap junctional communication in adult healthy or pathological brain. Copyright © 2018 Elsevier B.V. All rights reserved.

Method of euthanasia affects amygdala plasticity in horizontal brain slices from mice.

PubMed

Kulisch, C; Eckers, N; Albrecht, D

2011-10-15

An important consideration in any terminal experiment is the method used for euthanizing animals. Although the prime consideration is that the method is humane, some methods can have a dramatic impact on experimental outcomes. The standard inhalant anesthetic for experiments in brain slices is isoflurane, which replaced the flammable ethers used in the pioneer days of surgery. To our knowledge, there are no data available evaluating the effects of the method of euthanasia on plasticity changes in brain slices. Here, we compare the magnitude of long-term potentiation (LTP) and long-term depression (LTD) in the lateral nucleus of the amygdala (LA) after euthanasia following either ether or isoflurane anesthesia, as well as in mice decapitated without anesthesia. We found no differences in input-output curves using different methods of euthanasia. The LTP magnitude did not differ between ether and normal isoflurane anesthesia. After deep isoflurane anesthesia LTP induced by high frequency stimulation of cortical or intranuclear afferents was significantly reduced compared to ether anesthesia. In contrast to ether anesthesia and decapitation without anesthesia, the low frequency stimulation of cortical afferents induced a reliable LA-LTD after deep isoflurane anesthesia. Low frequency stimulation of intranuclear afferents only caused LTD after pretreatment with ether anesthesia. The results demonstrate that the method of euthanasia can influence brain plasticity for hours at least in the interface chamber. Therefore, the method of euthanasia is an important consideration when brain plasticity will be evaluated. Copyright © 2011 Elsevier B.V. All rights reserved.

[An integrated segmentation method for 3D ultrasound carotid artery].

PubMed

Yang, Xin; Wu, Huihui; Liu, Yang; Xu, Hongwei; Liang, Huageng; Cai, Wenjuan; Fang, Mengjie; Wang, Yujie

2013-07-01

An integrated segmentation method for 3D ultrasound carotid artery was proposed. 3D ultrasound image was sliced into transverse, coronal and sagittal 2D images on the carotid bifurcation point. Then, the three images were processed respectively, and the carotid artery contours and thickness were obtained finally. This paper tries to overcome the disadvantages of current computer aided diagnosis method, such as high computational complexity, easily introduced subjective errors et al. The proposed method could get the carotid artery overall information rapidly, accurately and completely. It could be transplanted into clinical usage for atherosclerosis diagnosis and prevention.

Effect of thrombin preconditioning on migration of subventricular zone-derived cells after intracerebral hemorrhage in rats.

PubMed

Guan, Jingxia; Zhang, Shaofeng; Zhou, Qin; Yuan, Zhenhua; Lu, Zuneng

2016-09-01

To investigate the effect of thrombin preconditioning (TPC) on the intracerebral hemorrhage (ICH)-induced proliferation, migration, and function of subventriclular zone (SVZ) cells and to find new strategies that enhance endogenous neurogenesis after ICH. Male Sprague-Dawley rats were randomly divided into 3 groups (ICH, TPC, and control group). Rats of each group were randomly divided into 5 subgroups (3-d, 7-d, 14-d, 21-d, and 28-d subgroup). ICH was caused by intrastrial stereotactic administration of collagenase type IV. Brdu was used to label newborn SVZ cells. Organotypic brain slices were cultured to dynamically observe the migration of SVZ cells at living brain tissue. Migration of Dil-labeled SVZ cells in living brain slices was traced by time-lapse microscopy. To assess whether SVZ cells migrating to injured striatum had the ability to form synapses with other cells, brain slices from each group were double immunolabeled with Brdu and synapsin I. The number of Brdu-positive cells markedly increased in the ipsilateral SVZ and striatum 3 days after TPC, peaked at 14 days (P < 0.01), continued to 21 days, and then gradually decreased at 28 days with significant difference compared to the ICH group at each time point (P < 0.01). Migration of Dil-labeled SVZ cells in brain slices in each group was observed and imaged during a 12-h period. Dil-labeled SVZ cells in the TPC group were observed to migrate laterally toward striatum with time with a faster velocity compared to the ICH group (P < 0.01). Our study also demonstrated that TPC induced strong colocalization of Brdu and synapsin I in the ipsilateral striatum between 3 and 28 days after injury.TPC made colocalization of Brdu and synapsin I appear earlier and continue for a longer time compared to the ICH group. Our results demonstrated that TPC could promote proliferation, migration, and function of SVZ cells after ICH, which may provide a new idea for enhancing endogenous neurogenesis and developing new therapeutic strategies against ICH-induced brain injury.

Correlations of recognition memory performance with expression and methylation of brain-derived neurotrophic factor in rats.

PubMed

Muñoz, Pablo C; Aspé, Mauricio A; Contreras, Luis S; Palacios, Adrián G

2010-01-01

Object recognition memory allows discrimination between novel and familiar objects. This kind of memory consists of two components: recollection, which depends on the hippocampus, and familiarity, which depends on the perirhinal cortex (Pcx). The importance of brain-derived neurotrophic factor (BDNF) for recognition memory has already been recognized. Recent evidence suggests that DNA methylation regulates the expression of BDNF and memory. Behavioral and molecular approaches were used to understand the potential contribution of DNA methylation to recognition memory. To that end, rats were tested for their ability to distinguish novel from familiar objects by using a spontaneous object recognition task. Furthermore, the level of DNA methylation was estimated after trials with a methyl-sensitive PCR. We found a significant correlation between performance on the novel object task and the expression of BDNF, negatively in hippocampal slices and positively in perirhinal cortical slices. By contrast, methylation of DNA in CpG island 1 in the promoter of exon 1 in BDNF only correlated in hippocampal slices, but not in the Pxc cortical slices from trained animals. These results suggest that DNA methylation may be involved in the regulation of the BDNF gene during recognition memory, at least in the hippocampus.

High-sensitivity terahertz imaging of traumatic brain injury in a rat model

NASA Astrophysics Data System (ADS)

Zhao, Hengli; Wang, Yuye; Chen, Linyu; Shi, Jia; Ma, Kang; Tang, Longhuang; Xu, Degang; Yao, Jianquan; Feng, Hua; Chen, Tunan

2018-03-01

We demonstrated that different degrees of experimental traumatic brain injury (TBI) can be differentiated clearly in fresh slices of rat brain tissues using transmission-type terahertz (THz) imaging system. The high absorption region in THz images corresponded well with the injured area in visible images and magnetic resonance imaging results. The THz image and absorption characteristics of dehydrated paraffin-embedded brain slices and the hematoxylin and eosin (H&E)-stained microscopic images were investigated to account for the intrinsic differences in the THz images for the brain tissues suffered from different degrees of TBI and normal tissue aside from water. The THz absorption coefficients of rat brain tissues showed an increase in the aggravation of brain damage, particularly in the high-frequency range, whereas the cell density decreased as the order of mild, moderate, and severe TBI tissues compared with the normal tissue. Our results indicated that the different degrees of TBI were distinguishable owing to the different water contents and probable hematoma components distribution rather than intrinsic cell intensity. These promising results suggest that THz imaging has great potential as an alternative method for the fast diagnosis of TBI.

A Military-Relevant Model of Closed Concussive Head Injury: Longitudinal Studies Characterizing and Validating Single and Repetitive mTBI

DTIC Science & Technology

2013-10-01

processed at FD Neurotechnologies Inc. (Ellicott City, MD, USA). A series of coronal free floating brain sections (40 μm; 960 µm interval from +4.0...axonal damage. Another series of coronal sections was stained using FD NeuroSilverTM Kit II (FD Neurotechnologies Inc., Ellicott City, MD, USA) for... Neurotechnologies Inc for processing and staining. Tissue processing and staining protocols have been optimized for fluorescent staining of AQ4 co

Ballistic delivery of dyes for structural and functional studies of the nervous system

PubMed Central

Gan, Wen-Biao; Grutzendler, Jaime; Wong, Rachel O.; Lichtman, Jeff W.

2010-01-01

This chapter describes a detail protocol for rapid labeling of cells in a variety of preparations by means of particle-mediated ballistic (gene gun) delivery of fluorescent dyes. This method has been used for rapid labeling of cells with either lipid or water-soluble dyes in a variety of preparations. In particular, carbocyanine lipophilic dyes such as DiI have been used to obtain Golgi-like labeling of neurons and glia in fixed and live cell cultures, brain slices, as well as fixed post-mortem human brain. Water-soluble calcium indicators such as calcium green-1 dextran have been used to image calcium dynamics in living brain slices and retinal explants. This ballistic labeling technique is thus useful for studying the structure and function of neurons and glia in both living and fixed specimens. PMID:20147144

In vivo Postnatal Electroporation and Time-lapse Imaging of Neuroblast Migration in Mouse Acute Brain Slices

PubMed Central

Oudin, Madeleine Julie; Doherty, Patrick; Lalli, Giovanna

2013-01-01

The subventricular zone (SVZ) is one of the main neurogenic niches in the postnatal brain. Here, neural progenitors proliferate and give rise to neuroblasts able to move along the rostral migratory stream (RMS) towards the olfactory bulb (OB). This long-distance migration is required for the subsequent maturation of newborn neurons in the OB, but the molecular mechanisms regulating this process are still unclear. Investigating the signaling pathways controlling neuroblast motility may not only help understand a fundamental step in neurogenesis, but also have therapeutic regenerative potential, given the ability of these neuroblasts to target brain sites affected by injury, stroke, or degeneration. In this manuscript we describe a detailed protocol for in vivo postnatal electroporation and subsequent time-lapse imaging of neuroblast migration in the mouse RMS. Postnatal electroporation can efficiently transfect SVZ progenitor cells, which in turn generate neuroblasts migrating along the RMS. Using confocal spinning disk time-lapse microscopy on acute brain slice cultures, neuroblast migration can be monitored in an environment closely resembling the in vivo condition. Moreover, neuroblast motility can be tracked and quantitatively analyzed. As an example, we describe how to use in vivo postnatal electroporation of a GFP-expressing plasmid to label and visualize neuroblasts migrating along the RMS. Electroporation of shRNA or CRE recombinase-expressing plasmids in conditional knockout mice employing the LoxP system can also be used to target genes of interest. Pharmacological manipulation of acute brain slice cultures can be performed to investigate the role of different signaling molecules in neuroblast migration. By coupling in vivo electroporation with time-lapse imaging, we hope to understand the molecular mechanisms controlling neuroblast motility and contribute to the development of novel approaches to promote brain repair. PMID:24326479

[Imaging of the intrahepatic biliary tree with thick slice MR cholangiography].

PubMed

Leclerc, J C; Cannard, L; Lefèvre, F; Debelle, L; Béot, S; Boccaccini, H; Bazin, C; Régent, D

2001-02-01

To assess the value of single shot fast spin echo MR sequence (SS-FSE) in the evaluation of the normal and pathologic intrahepatic biliary tree. 418 consecutive patients (457 examinations) referred for clinical and/or biological suspicion of biliary obstruction underwent MR cholangiopancreatography (MRCP). All patients were imaged with a Signa 1.5 T GE MR unit, with High Gradient Field Strength and Torso Phased Array Coil. Biliary ducts were imaged with SS-FSE sequence, coronal and oblique coronal 20 mm thick slices on a 256 x 256 matrix. Total acquisition time was 1 second. Source images were reviewed by two radiologists blinded to clinical information. In case of disagreement, a third radiologist's opinion was requested. In all cases, MRCP results were compared with direct biliary tract evaluation, other imaging studies and clinical and biological follow-up. In all cases, MRCP produced high quality images. Numerous branch of division were observed although the peripheral intrahepatic ducts were well seen in more than 90% in an area 2 cm below the capsule. The number of division was statistically higher when mechanical obstruction was present. Intrahepatic calculi or peripheral cholangiocarcinoma were well detect by MRCP. For the detection of cholangitis, MRCP sensitivity was 87.5% but the positive predictive value was only 57.7% because of a high number of false positive. The diagnosis of primary sclerosing cholangitis must be made only on strict criteria and slightly dilated peripheral bile ducts unconnected to the central ducts in several hepatic segments were a characteristic MR sign of primary sclerosing cholangitis. MRCP can be proposed as a first intention imaging technique for the evaluation of intrahepatic ducts.

The value of "liver windows" settings in the detection of small renal cell carcinomas on unenhanced computed tomography.

PubMed

Sahi, Kamal; Jackson, Stuart; Wiebe, Edward; Armstrong, Gavin; Winters, Sean; Moore, Ronald; Low, Gavin

2014-02-01

To assess if "liver window" settings improve the conspicuity of small renal cell carcinomas (RCC). Patients were analysed from our institution's pathology-confirmed RCC database that included the following: (1) stage T1a RCCs, (2) an unenhanced computed tomography (CT) abdomen performed ≤ 6 months before histologic diagnosis, and (3) age ≥ 17 years. Patients with multiple tumours, prior nephrectomy, von Hippel-Lindau disease, and polycystic kidney disease were excluded. The unenhanced CT was analysed, and the tumour locations were confirmed by using corresponding contrast-enhanced CT or magnetic resonance imaging studies. Representative single-slice axial, coronal, and sagittal unenhanced CT images were acquired in "soft tissue windows" (width, 400 Hounsfield unit (HU); level, 40 HU) and liver windows (width, 150 HU; level, 88 HU). In addition, single-slice axial, coronal, and sagittal unenhanced CT images of nontumourous renal tissue (obtained from the same cases) were acquired in soft tissue windows and liver windows. These data sets were randomized, unpaired, and were presented independently to 3 blinded radiologists for analysis. The presence or absence of suspicious findings for tumour was scored on a 5-point confidence scale. Eighty-three of 415 patients met the study criteria. Receiver operating characteristics (ROC) analysis, t test analysis, and kappa analysis were used. ROC analysis showed statistically superior diagnostic performance for liver windows compared with soft tissue windows (area under the curve of 0.923 vs 0.879; P = .0002). Kappa statistics showed "good" vs "moderate" agreement between readers for liver windows compared with soft tissue windows. Use of liver windows settings improves the detection of small RCCs on the unenhanced CT. Copyright © 2014 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

"The Most Famous Brain in the World" Performance and Pedagogy on an Amnesiac's Brain

ERIC Educational Resources Information Center

Sweaney, Katherine W.

2012-01-01

Project H.M. was just the sort of thing one might expect the Internet to latch onto: it was a live streaming video of a frozen human brain being slowly sliced apart. Users who clicked the link on Twitter or Facebook between the 2nd and 4th of December 2009 were immediately confronted with a close-up shot of the brain's interior, which was…

A novel slice preparation to study medullary oromotor and autonomic circuits in vitro

PubMed Central

Nasse, Jason S.

2014-01-01

Background The medulla is capable of controlling and modulating ingestive behavior and gastrointestinal function. These two functions, which are critical to maintaining homeostasis, are governed by an interconnected group of nuclei dispersed throughout the medulla. As such, in vitro experiments to study the neurophysiologic details of these connections have been limited by spatial constraints of conventional slice preparations. New method This study demonstrates a novel method of sectioning the medulla so that sensory, integrative, and motor nuclei that innervate the gastrointestinal tract and the oral cavity remain intact. Results: Immunohistochemical staining against choline-acetyl-transferase and dopamine-β-hydroxylase demonstrated that within a 450 μm block of tissue we are able to capture sensory, integrative and motor nuclei that are critical to oromotor and gastrointestinal function. Within slice tracing shows that axonal projections from the NST to the reticular formation and from the reticular formation to the hypoglossal motor nucleus (mXII) persist. Live-cell calcium imaging of the slice demonstrates that stimulation of either the rostral or caudal NST activates neurons throughout the NST, as well as the reticular formation and mXII. Comparison with existing methods This new method of sectioning captures a majority of the nuclei that are active when ingesting a meal. Tradition planes of section, i.e. coronal, horizontal or sagittal, contain only a limited portion of the substrate. Conclusions Our results demonstrate that both anatomical and physiologic connections of oral and visceral sensory nuclei that project to integrative and motor nuclei remain intact with this new plane of section. PMID:25196216

A novel slice preparation to study medullary oromotor and autonomic circuits in vitro.

PubMed

Nasse, Jason S

2014-11-30

The medulla is capable of controlling and modulating ingestive behavior and gastrointestinal function. These two functions, which are critical to maintaining homeostasis, are governed by an interconnected group of nuclei dispersed throughout the medulla. As such, in vitro experiments to study the neurophysiologic details of these connections have been limited by spatial constraints of conventional slice preparations. This study demonstrates a novel method of sectioning the medulla so that sensory, integrative, and motor nuclei that innervate the gastrointestinal tract and the oral cavity remain intact. Immunohistochemical staining against choline-acetyl-transferase and dopamine-β-hydroxylase demonstrated that within a 450 μm block of tissue we are able to capture sensory, integrative and motor nuclei that are critical to oromotor and gastrointestinal function. Within slice tracing shows that axonal projections from the NST to the reticular formation and from the reticular formation to the hypoglossal motor nucleus (mXII) persist. Live-cell calcium imaging of the slice demonstrates that stimulation of either the rostral or caudal NST activates neurons throughout the NST, as well as the reticular formation and mXII. This new method of sectioning captures a majority of the nuclei that are active when ingesting a meal. Tradition planes of section, i.e. coronal, horizontal or sagittal, contain only a limited portion of the substrate. Our results demonstrate that both anatomical and physiologic connections of oral and visceral sensory nuclei that project to integrative and motor nuclei remain intact with this new plane of section. Published by Elsevier B.V.

TH-EF-BRA-08: A Novel Technique for Estimating Volumetric Cine MRI (VC-MRI) From Multi-Slice Sparsely Sampled Cine Images Using Motion Modeling and Free Form Deformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, W; Yin, F; Wang, C

Purpose: To develop a technique to estimate on-board VC-MRI using multi-slice sparsely-sampled cine images, patient prior 4D-MRI, motion-modeling and free-form deformation for real-time 3D target verification of lung radiotherapy. Methods: A previous method has been developed to generate on-board VC-MRI by deforming prior MRI images based on a motion model(MM) extracted from prior 4D-MRI and a single-slice on-board 2D-cine image. In this study, free-form deformation(FD) was introduced to correct for errors in the MM when large anatomical changes exist. Multiple-slice sparsely-sampled on-board 2D-cine images located within the target are used to improve both the estimation accuracy and temporal resolution ofmore » VC-MRI. The on-board 2D-cine MRIs are acquired at 20–30frames/s by sampling only 10% of the k-space on Cartesian grid, with 85% of that taken at the central k-space. The method was evaluated using XCAT(computerized patient model) simulation of lung cancer patients with various anatomical and respirational changes from prior 4D-MRI to onboard volume. The accuracy was evaluated using Volume-Percent-Difference(VPD) and Center-of-Mass-Shift(COMS) of the estimated tumor volume. Effects of region-of-interest(ROI) selection, 2D-cine slice orientation, slice number and slice location on the estimation accuracy were evaluated. Results: VCMRI estimated using 10 sparsely-sampled sagittal 2D-cine MRIs achieved VPD/COMS of 9.07±3.54%/0.45±0.53mm among all scenarios based on estimation with ROI-MM-ROI-FD. The FD optimization improved estimation significantly for scenarios with anatomical changes. Using ROI-FD achieved better estimation than global-FD. Changing the multi-slice orientation to axial, coronal, and axial/sagittal orthogonal reduced the accuracy of VCMRI to VPD/COMS of 19.47±15.74%/1.57±2.54mm, 20.70±9.97%/2.34±0.92mm, and 16.02±13.79%/0.60±0.82mm, respectively. Reducing the number of cines to 8 enhanced temporal resolution of VC-MRI by 25% while maintaining the estimation accuracy. Estimation using slices sampled uniformly through the tumor achieved better accuracy than slices sampled non-uniformly. Conclusions: Preliminary studies showed that it is feasible to generate VC-MRI from multi-slice sparsely-sampled 2D-cine images for real-time 3D-target verification. This work was supported by the National Institutes of Health under Grant No. R01-CA184173 and a research grant from Varian Medical Systems.« less

Bacterial Cytolysin during Meningitis Disrupts the Regulation of Glutamate in the Brain, Leading to Synaptic Damage

PubMed Central

Wippel, Carolin; Maurer, Jana; Förtsch, Christina; Hupp, Sabrina; Bohl, Alexandra; Ma, Jiangtao; Mitchell, Timothy J.; Bunkowski, Stephanie; Brück, Wolfgang; Nau, Roland; Iliev, Asparouh I.

2013-01-01

Streptococcus pneumoniae (pneumococcal) meningitis is a common bacterial infection of the brain. The cholesterol-dependent cytolysin pneumolysin represents a key factor, determining the neuropathogenic potential of the pneumococci. Here, we demonstrate selective synaptic loss within the superficial layers of the frontal neocortex of post-mortem brain samples from individuals with pneumococcal meningitis. A similar effect was observed in mice with pneumococcal meningitis only when the bacteria expressed the pore-forming cholesterol-dependent cytolysin pneumolysin. Exposure of acute mouse brain slices to only pore-competent pneumolysin at disease-relevant, non-lytic concentrations caused permanent dendritic swelling, dendritic spine elimination and synaptic loss. The NMDA glutamate receptor antagonists MK801 and D-AP5 reduced this pathology. Pneumolysin increased glutamate levels within the mouse brain slices. In mouse astrocytes, pneumolysin initiated the release of glutamate in a calcium-dependent manner. We propose that pneumolysin plays a significant synapto- and dendritotoxic role in pneumococcal meningitis by initiating glutamate release from astrocytes, leading to subsequent glutamate-dependent synaptic damage. We outline for the first time the occurrence of synaptic pathology in pneumococcal meningitis and demonstrate that a bacterial cytolysin can dysregulate the control of glutamate in the brain, inducing excitotoxic damage. PMID:23785278

Super-resolution reconstruction in frequency, image, and wavelet domains to reduce through-plane partial voluming in MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gholipour, Ali, E-mail: ali.gholipour@childrens.harvard.edu; Afacan, Onur; Scherrer, Benoit

Purpose: To compare and evaluate the use of super-resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through-plane partial voluming effects in magnetic resonance imaging. Methods: The reconstruction of an isotropic high-resolution image from multiple thick-slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick-slice T2-weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high-resolution scan using peak signal-to-noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) ofmore » image intensity profiles. The application of super-resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through-plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities. Results: Quantitative evaluation results show improvements in all evaluation metrics through super-resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image-domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in-plane and out-of-plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in resampled out-of-plane views consistently showed the superiority of SRR compared to original axial and coronal image acquisitions. Conclusions: Thick-slice 2D T2-weighted MRI scans are part of many routine clinical protocols due to their high signal-to-noise ratio, but are often severely affected by through-plane partial voluming effects. This study shows that while radiologic assessment is performed in 2D on thick-slice scans, super-resolution MRI reconstruction techniques can be used to fuse those scans to generate a high-resolution image with reduced partial voluming for improved postacquisition processing. Qualitative and quantitative evaluation showed the efficacy of all SRR techniques with the best results obtained from SRR in the image domain. The limitations of SRR techniques are uncertainties in modeling the slice profile, density compensation, quantization in resampling, and uncompensated motion between scans.« less

Super-resolution reconstruction in frequency, image, and wavelet domains to reduce through-plane partial voluming in MRI

PubMed Central

Gholipour, Ali; Afacan, Onur; Aganj, Iman; Scherrer, Benoit; Prabhu, Sanjay P.; Sahin, Mustafa; Warfield, Simon K.

2015-01-01

Purpose: To compare and evaluate the use of super-resolution reconstruction (SRR), in frequency, image, and wavelet domains, to reduce through-plane partial voluming effects in magnetic resonance imaging. Methods: The reconstruction of an isotropic high-resolution image from multiple thick-slice scans has been investigated through techniques in frequency, image, and wavelet domains. Experiments were carried out with thick-slice T2-weighted fast spin echo sequence on the Academic College of Radiology MRI phantom, where the reconstructed images were compared to a reference high-resolution scan using peak signal-to-noise ratio (PSNR), structural similarity image metric (SSIM), mutual information (MI), and the mean absolute error (MAE) of image intensity profiles. The application of super-resolution reconstruction was then examined in retrospective processing of clinical neuroimages of ten pediatric patients with tuberous sclerosis complex (TSC) to reduce through-plane partial voluming for improved 3D delineation and visualization of thin radial bands of white matter abnormalities. Results: Quantitative evaluation results show improvements in all evaluation metrics through super-resolution reconstruction in the frequency, image, and wavelet domains, with the highest values obtained from SRR in the image domain. The metric values for image-domain SRR versus the original axial, coronal, and sagittal images were PSNR = 32.26 vs 32.22, 32.16, 30.65; SSIM = 0.931 vs 0.922, 0.924, 0.918; MI = 0.871 vs 0.842, 0.844, 0.831; and MAE = 5.38 vs 7.34, 7.06, 6.19. All similarity metrics showed high correlations with expert ranking of image resolution with MI showing the highest correlation at 0.943. Qualitative assessment of the neuroimages of ten TSC patients through in-plane and out-of-plane visualization of structures showed the extent of partial voluming effect in a real clinical scenario and its reduction using SRR. Blinded expert evaluation of image resolution in resampled out-of-plane views consistently showed the superiority of SRR compared to original axial and coronal image acquisitions. Conclusions: Thick-slice 2D T2-weighted MRI scans are part of many routine clinical protocols due to their high signal-to-noise ratio, but are often severely affected by through-plane partial voluming effects. This study shows that while radiologic assessment is performed in 2D on thick-slice scans, super-resolution MRI reconstruction techniques can be used to fuse those scans to generate a high-resolution image with reduced partial voluming for improved postacquisition processing. Qualitative and quantitative evaluation showed the efficacy of all SRR techniques with the best results obtained from SRR in the image domain. The limitations of SRR techniques are uncertainties in modeling the slice profile, density compensation, quantization in resampling, and uncompensated motion between scans. PMID:26632048

Lipopolysaccharides do not alter metabolic disturbances in hippocampal slices of fetal guinea pigs after oxygen-glucose deprivation.

PubMed

Berger, R; Garnier, Y; Pfeiffer, D; Jensen, A

2000-10-01

The aim of the present study was to clarify whether endotoxins [lipopolysaccharides (LPS)] have a toxic effect on fetal brain tissue after cerebral ischemia, while excluding their effect on the cardiovascular system. Experiments were therefore performed on hippocampal slices prepared from mature fetal guinea pigs. In particular, we studied the influence of LPS on nitric oxide production, energy metabolism, and protein synthesis after oxygen-glucose deprivation (OGD). Incubating hippocampal slices in LPS (4 mg/L) for as long as 12 h did not alter cGMP tissue concentrations significantly. However, 10 min after OGD of 40-min duration, cGMP tissue concentrations were substantially increased in relation to controls, and this increase was almost completely blocked by the application of 100 microM N:(omega)-nitro-L-arginine, indicating that nitric oxide synthase was activated after OGD in fetal brain tissue. Again, LPS did not have any effect on cGMP tissue concentrations after OGD. Furthermore, addition of LPS altered neither protein synthesis nor energy metabolism measured 12 h after OGD. We therefore conclude that, apart from their well-known influence on the cardiovascular system, LPS do not alter metabolic disturbances in hippocampal slices of fetal guinea pigs 12 h after OGD. A direct toxic effect of LPS on immature brain tissue within this interval does not therefore seem to be very likely. However, delayed activation of LPS-sensitive pathways that may be involved in cell death, or damage limited to a small subgroup of cells such as oligodendrocyte progenitors, cannot be fully excluded.

In vitro 6-hydroxydopamine-induced toxicity in striatal, cerebrocortical and hippocampal slices is attenuated by atorvastatin and MK-801.

PubMed

Massari, Caio M; Castro, Adalberto A; Dal-Cim, Tharine; Lanznaster, Débora; Tasca, Carla I

2016-12-01

Parkinson's disease (PD) involves the loss of striatal dopaminergic neurons, although other neurotransmitters and brain areas are also involved in its pathophysiology. In rodent models to PD it has been shown statins improve cognitive and motor deficits and attenuate inflammatory responses evoked by PD-related toxins. Statins are the drugs most prescribed to hypercholesterolemia, but neuroprotective effects have also been attributed to statins treatment in humans and in animal models. This study aimed to establish an in vitro model of 6-hydroxydopamine (6-OHDA)-induced toxicity, used as an initial screening test to identify effective drugs against neural degeneration related to PD. The putative neuroprotective effect of atorvastatin against 6-OHDA-induced toxicity in rat striatal, cerebrocortical and hippocampal slices was also evaluated. 6-OHDA (100μM) decreased cellular viability in slices obtained from rat cerebral cortex, hippocampus and striatum. 6-OHDA also induced an increased reactive oxygen species (ROS) production and mitochondrial dysfunction. Co-incubation of 6-OHDA with atorvastatin (10μM) or MK-801 (50μM) an N-methyl-d-aspartate (NMDA) receptor antagonist, partially attenuated the cellular damage evoked by 6-OHDA in the three brain areas. Atorvastatin partially reduced ROS production in the hippocampus and striatum and disturbances of mitochondria membrane potential in cortex and striatum. 6-OHDA-induced toxicity in vitro displays differences among the brain structures, but it is also observed in cerebrocortical and hippocampal slices, besides striatum. Copyright © 2016 Elsevier B.V. All rights reserved.

Use of pattern recognition for unaliasing simultaneously acquired slices in simultaneous multislice MR fingerprinting.

PubMed

Jiang, Yun; Ma, Dan; Bhat, Himanshu; Ye, Huihui; Cauley, Stephen F; Wald, Lawrence L; Setsompop, Kawin; Griswold, Mark A

2017-11-01

The purpose of this study is to accelerate an MR fingerprinting (MRF) acquisition by using a simultaneous multislice method. A multiband radiofrequency (RF) pulse was designed to excite two slices with different flip angles and phases. The signals of two slices were driven to be as orthogonal as possible. The mixed and undersampled MRF signal was matched to two dictionaries to retrieve T 1 and T 2 maps of each slice. Quantitative results from the proposed method were validated with the gold-standard spin echo methods in a phantom. T 1 and T 2 maps of in vivo human brain from two simultaneously acquired slices were also compared to the results of fast imaging with steady-state precession based MRF method (MRF-FISP) with a single-band RF excitation. The phantom results showed that the simultaneous multislice imaging MRF-FISP method quantified the relaxation properties accurately compared to the gold-standard spin echo methods. T 1 and T 2 values of in vivo brain from the proposed method also matched the results from the normal MRF-FISP acquisition. T 1 and T 2 values can be quantified at a multiband acceleration factor of two using our proposed acquisition even in a single-channel receive coil. Further acceleration could be achieved by combining this method with parallel imaging or iterative reconstruction. Magn Reson Med 78:1870-1876, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Ethanol exposure during the third trimester equivalent does not affect GABAA or AMPA receptor-mediated spontaneous synaptic transmission in rat CA3 pyramidal neurons.

PubMed

Baculis, Brian Charles; Valenzuela, Carlos Fernando

2015-12-02

Ethanol exposure during the rodent equivalent to the 3(rd) trimester of human pregnancy (i.e., first 1-2 weeks of neonatal life) has been shown to produce structural and functional alterations in the CA3 hippocampal sub-region, which is involved in associative memory. Synaptic plasticity mechanisms dependent on retrograde release of brain-derived neurotrophic factor (BDNF) driven by activation of L-type voltage-gated Ca(2+) channels (L-VGCCs) are thought to play a role in stabilization of both GABAergic and glutamatergic synapses in CA3 pyramidal neurons. We previously showed that ethanol exposure during the first week of life blocks BDNF/L-VGCC-dependent long-term potentiation of GABAA receptor-mediated synaptic transmission in these neurons. Here, we tested whether this effect is associated with lasting alterations in GABAergic and glutamatergic transmission. Rats were exposed to air or ethanol for 3 h/day between postnatal days three and five in vapor inhalation chambers, a paradigm that produces peak serum ethanol levels near 0.3 g/dl. Whole-cell patch-clamp electrophysiological recordings of spontaneous inhibitory and excitatory postsynaptic currents (sIPSCs and sEPSCs, respectively) were obtained from CA3 pyramidal neurons in coronal brain slices prepared at postnatal days 13-17. Ethanol exposure did not significantly affect the frequency, amplitude, rise-time and half-width of either sIPSCs or sEPSCs. We show that an ethanol exposure paradigm known to inhibit synaptic plasticity mechanisms that may participate in the stabilization of GABAergic and glutamatergic synapses in CA3 pyramidal neurons does not produce lasting functional alterations in these synapses, suggesting that compensatory mechanisms restored the balance of excitatory and inhibitory synaptic transmission.

Neuroanatomy-based matrix-guided trimming protocol for the rat brain.

PubMed

Defazio, Rossella; Criado, Ana; Zantedeschi, Valentina; Scanziani, Eugenio

2015-02-01

Brain trimming through defined neuroanatomical landmarks is recommended to obtain consistent sections in rat toxicity studies. In this article, we describe a matrix-guided trimming protocol that uses channels to reproduce coronal levels of anatomical landmarks. Both setup phase and validation study were performed on Han Wistar male rats (Crl:WI(Han)), 10-week-old, with bodyweight of 298 ± 29 (SD) g, using a matrix (ASI-Instruments(®), Houston, TX) fitted for brains of rats with 200 to 400 g bodyweight. In the setup phase, we identified eight channels, that is, 6, 8, 10, 12, 14, 16, 19, and 21, matching the recommended landmarks midway to the optic chiasm, frontal pole, optic chiasm, infundibulum, mamillary bodies, midbrain, middle cerebellum, and posterior cerebellum, respectively. In the validation study, we trimmed the immersion-fixed brains of 60 rats using the selected channels to determine how consistently the channels reproduced anatomical landmarks. Percentage of success (i.e., presence of expected targets for each level) ranged from 89 to 100%. Where 100% success was not achieved, it was noted that the shift in brain trimming was toward the caudal pole. In conclusion, we developed and validated a trimming protocol for the rat brain that allow comparable extensiveness, homology, and relevance of coronal sections as the landmark-guided trimming with the advantage of being quickly learned by technicians. © 2014 by The Author(s).

Age Dependency of Inhibition of α7 Nicotinic Receptors and Tonically Active N-Methyl-d-aspartate Receptors by Endogenously Produced Kynurenic Acid in the Brain

PubMed Central

Alkondon, Manickavasagom; Pereira, Edna F. R.; Eisenberg, Howard M.; Kajii, Yasushi; Schwarcz, Robert

2011-01-01

In the mouse hippocampus normal levels of kynurenic acid (KYNA), a neuroactive metabolite synthesized in astrocytes primarily by kynurenine aminotransferase II (KAT II)-catalyzed transamination of l-kynurenine, maintain a degree of tonic inhibition of α7 nicotinic acetylcholine receptors (nAChRs). The present in vitro study was designed to test the hypothesis that α7 nAChR activity decreases when endogenous production of KYNA increases. Incubation (2–7 h) of rat hippocampal slices with kynurenine (200 μM) resulted in continuous de novo synthesis of KYNA. Kynurenine conversion to KYNA was significantly decreased by the KAT II inhibitor (S)-(−)-9-(4-aminopiperazine-1-yl)-8-fluoro-3-methyl-6-oxo-2,3,5,6-tetrahydro-4H-1-oxa-3a-azaphenalene-5carboxylic acid (BFF122) (100 μM) and was more effective in slices from postweaned than preweaned rats. Incubation of slices from postweaned rats with kynurenine inhibited α7 nAChRs and extrasynaptic N-methyl-d-aspartate receptors (NMDARs) on CA1 stratum radiatum interneurons. These effects were attenuated by BFF122 and mimicked by exogenously applied KYNA (200 μM). Exposure of human cerebral cortical slices to kynurenine also inhibited α7 nAChRs. The α7 nAChR sensitivity to KYNA is age-dependent, because neither endogenously produced nor exogenously applied KYNA inhibited α7 nAChRs in slices from preweaned rats. In these slices, kynurenine-derived KYNA also failed to inhibit extrasynaptic NMDARs, which could, however, be inhibited by exogenously applied KYNA. In slices from preweaned and postweaned rats, glutamatergic synaptic currents were not affected by endogenously produced KYNA, but were inhibited by exogenously applied KYNA. These results suggest that in the mature brain α7 nAChRs and extrasynaptic NMDARs are in close apposition to KYNA release sites and, thereby, readily accessible to inhibition by endogenously produced KYNA. PMID:21270133

Bayesian framework inspired no-reference region-of-interest quality measure for brain MRI images

PubMed Central

Osadebey, Michael; Pedersen, Marius; Arnold, Douglas; Wendel-Mitoraj, Katrina

2017-01-01

Abstract. We describe a postacquisition, attribute-based quality assessment method for brain magnetic resonance imaging (MRI) images. It is based on the application of Bayes theory to the relationship between entropy and image quality attributes. The entropy feature image of a slice is segmented into low- and high-entropy regions. For each entropy region, there are three separate observations of contrast, standard deviation, and sharpness quality attributes. A quality index for a quality attribute is the posterior probability of an entropy region given any corresponding region in a feature image where quality attribute is observed. Prior belief in each entropy region is determined from normalized total clique potential (TCP) energy of the slice. For TCP below the predefined threshold, the prior probability for a region is determined by deviation of its percentage composition in the slice from a standard normal distribution built from 250 MRI volume data provided by Alzheimer’s Disease Neuroimaging Initiative. For TCP above the threshold, the prior is computed using a mathematical model that describes the TCP–noise level relationship in brain MRI images. Our proposed method assesses the image quality of each entropy region and the global image. Experimental results demonstrate good correlation with subjective opinions of radiologists for different types and levels of quality distortions. PMID:28630885

A combined long-term recording system for single-unit activity and neurotransmitter efflux of a brain slice

NASA Astrophysics Data System (ADS)

Sheu, Y. H.; Young, M. S.

1998-04-01

A combined long-term measurement and recording system for neurotransmission research of brain slices is presented in this study. This system, based on the IBM PC or compatible computer, is capable of simultaneously measuring and recording both single-unit neural electropotential signals and the electrochemical signals of neurotransmitter efflux from the same neuron in a brain slice for long periods of time (time limited largely by hard disk capacity, 100 h or more not being unreasonable with contemporary hardware) using a single carbon microelectrode for both measurements. The combined long-term recording system uses a simple switching circuit to switch periodically the single microelectrode between two data acquisition subsystems, one for electrochemical data and one for electrophysiological data. The simple switching circuit separates the electrophysiological signals and electrochemical signals, overcoming the traditional interference problem caused by the two different measuring techniques. Software designed for the proposed system allows easy reconstruction of the full time course of the compressed measured data and easy, simultaneous display of both types of signals on the same time scale. On-line and recorded displays are available. Test results of a practical implementation of the proposed system verify that the combined long-term recording system meets actual requirements for electrophysiological and neurochemical research.

Automatic MRI 2D brain segmentation using graph searching technique.

PubMed

Pedoia, Valentina; Binaghi, Elisabetta

2013-09-01

Accurate and efficient segmentation of the whole brain in magnetic resonance (MR) images is a key task in many neuroscience and medical studies either because the whole brain is the final anatomical structure of interest or because the automatic extraction facilitates further analysis. The problem of segmenting brain MRI images has been extensively addressed by many researchers. Despite the relevant achievements obtained, automated segmentation of brain MRI imagery is still a challenging problem whose solution has to cope with critical aspects such as anatomical variability and pathological deformation. In the present paper, we describe and experimentally evaluate a method for segmenting brain from MRI images basing on two-dimensional graph searching principles for border detection. The segmentation of the whole brain over the entire volume is accomplished slice by slice, automatically detecting frames including eyes. The method is fully automatic and easily reproducible by computing the internal main parameters directly from the image data. The segmentation procedure is conceived as a tool of general applicability, although design requirements are especially commensurate with the accuracy required in clinical tasks such as surgical planning and post-surgical assessment. Several experiments were performed to assess the performance of the algorithm on a varied set of MRI images obtaining good results in terms of accuracy and stability. Copyright © 2012 John Wiley & Sons, Ltd.

Registration of in vivo MR to histology of rodent brains using blockface imaging

NASA Astrophysics Data System (ADS)

Uberti, Mariano; Liu, Yutong; Dou, Huanyu; Mosley, R. Lee; Gendelman, Howard E.; Boska, Michael

2009-02-01

Registration of MRI to histopathological sections can enhance bioimaging validation for use in pathobiologic, diagnostic, and therapeutic evaluations. However, commonly used registration methods fall short of this goal due to tissue shrinkage and tearing after brain extraction and preparation. In attempts to overcome these limitations we developed a software toolbox using 3D blockface imaging as the common space of reference. This toolbox includes a semi-automatic brain extraction technique using constraint level sets (CLS), 3D reconstruction methods for the blockface and MR volume, and a 2D warping technique using thin-plate splines with landmark optimization. Using this toolbox, the rodent brain volume is first extracted from the whole head MRI using CLS. The blockface volume is reconstructed followed by 3D brain MRI registration to the blockface volume to correct the global deformations due to brain extraction and fixation. Finally, registered MRI and histological slices are warped to corresponding blockface images to correct slice specific deformations. The CLS brain extraction technique was validated by comparing manual results showing 94% overlap. The image warping technique was validated by calculating target registration error (TRE). Results showed a registration accuracy of a TRE < 1 pixel. Lastly, the registration method and the software tools developed were used to validate cell migration in murine human immunodeficiency virus type one encephalitis.

Comparison of effectiveness between cork-screw and peg-screw electrodes for transcranial motor evoked potential monitoring using the finite element method.

PubMed

Tomio, Ryosuke; Akiyama, Takenori; Ohira, Takayuki; Yoshida, Kazunari

2016-01-01

Intraoperative monitoring of motor evoked potentials by transcranial electric stimulation is popular in neurosurgery for monitoring motor function preservation. Some authors have reported that the peg-screw electrodes screwed into the skull can more effectively conduct current to the brain compared to subdermal cork-screw electrodes screwed into the skin. The aim of this study was to investigate the influence of electrode design on transcranial motor evoked potential monitoring. We estimated differences in effectiveness between the cork-screw electrode, peg-screw electrode, and cortical electrode to produce electric fields in the brain. We used the finite element method to visualize electric fields in the brain generated by transcranial electric stimulation using realistic three-dimensional head models developed from T1-weighted images. Surfaces from five layers of the head were separated as accurately as possible. We created the "cork-screws model," "1 peg-screw model," "peg-screws model," and "cortical electrode model". Electric fields in the brain radially diffused from the brain surface at a maximum just below the electrodes in coronal sections. The coronal sections and surface views of the brain showed higher electric field distributions under the peg-screw compared to the cork-screw. An extremely high electric field was observed under cortical electrodes. Our main finding was that the intensity of electric fields in the brain are higher in the peg-screw model than the cork-screw model.

A serine peptidase responsible for the inactivation of endogenous cholecystokinin in brain.

PubMed

Rose, C; Camus, A; Schwartz, J C

1988-11-01

A serine endopeptidase was characterized as a major inactivating enzyme for endogenous cholecystokinin (CCK) in brain. CCK-8 released by depolarization of slices of rat cerebral cortex, as measured by its immunoreactivity (CCK-ir), undergoes extensive degradation (approximately 85% of the amount released) before reaching the incubation medium. However, recovery of CCK-ir is enhanced up to 3-fold in the presence of serine-alkylating reagents (i.e., phenylmethylsulfonyl fluoride) as well as selected active site-directed inactivators (i.e., peptide chloromethyl ketones) or transition-state inhibitors (i.e., peptide boronic acids) of serine peptidases. Among these compounds, elastase inhibitors were the most potent protecting agents, whereas trypsin or chymotrypsin inhibitors were ineffective. HPLC analysis of endogenous CCK-ir recovered in media of depolarized slices indicated that endogenous CCK-5 [CCK-(29-33)-pentapeptide] was the most abundant fragment and that its formation was strongly decreased in the presence of an elastase inhibitor. HPLC analysis of fragments formed upon incubation of exogenous CCK-8 [CCK-(26-33)-octapeptide] with brain slices showed CCK-5, Gly-Trp-Met, and Trp-Met to be major metabolites of CCK-8 whose formation was prevented or at least diminished in the presence of the elastase inhibitor. It is concluded that there is an elastase-like serine endopeptidase in brain that cleaves the two peptide bonds of CCK-8 where the carboxyl group is donated by a methionine residue and constitutes a major inactivation ectoenzyme for the neuropeptide.

A serine peptidase responsible for the inactivation of endogenous cholecystokinin in brain.

PubMed Central

Rose, C; Camus, A; Schwartz, J C

1988-01-01

A serine endopeptidase was characterized as a major inactivating enzyme for endogenous cholecystokinin (CCK) in brain. CCK-8 released by depolarization of slices of rat cerebral cortex, as measured by its immunoreactivity (CCK-ir), undergoes extensive degradation (approximately 85% of the amount released) before reaching the incubation medium. However, recovery of CCK-ir is enhanced up to 3-fold in the presence of serine-alkylating reagents (i.e., phenylmethylsulfonyl fluoride) as well as selected active site-directed inactivators (i.e., peptide chloromethyl ketones) or transition-state inhibitors (i.e., peptide boronic acids) of serine peptidases. Among these compounds, elastase inhibitors were the most potent protecting agents, whereas trypsin or chymotrypsin inhibitors were ineffective. HPLC analysis of endogenous CCK-ir recovered in media of depolarized slices indicated that endogenous CCK-5 [CCK-(29-33)-pentapeptide] was the most abundant fragment and that its formation was strongly decreased in the presence of an elastase inhibitor. HPLC analysis of fragments formed upon incubation of exogenous CCK-8 [CCK-(26-33)-octapeptide] with brain slices showed CCK-5, Gly-Trp-Met, and Trp-Met to be major metabolites of CCK-8 whose formation was prevented or at least diminished in the presence of the elastase inhibitor. It is concluded that there is an elastase-like serine endopeptidase in brain that cleaves the two peptide bonds of CCK-8 where the carboxyl group is donated by a methionine residue and constitutes a major inactivation ectoenzyme for the neuropeptide. PMID:3186727

Purinergic signaling triggers endfoot high-amplitude Ca2+ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage

PubMed Central

Pappas, Anthony C; Koide, Masayo

2016-01-01

Neurovascular coupling supports brain metabolism by matching focal increases in neuronal activity with local arteriolar dilation. Previously, we demonstrated that an emergence of spontaneous endfoot high-amplitude Ca2+ signals (eHACSs) caused a pathologic shift in neurovascular coupling from vasodilation to vasoconstriction in brain slices obtained from subarachnoid hemorrhage model animals. Extracellular purine nucleotides (e.g., ATP) can trigger astrocyte Ca2+ oscillations and may be elevated following subarachnoid hemorrhage. Here, the role of purinergic signaling in subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling was examined by imaging parenchymal arteriolar diameter and astrocyte Ca2+ signals in rat brain slices using two-photon fluorescent and infrared-differential interference contrast microscopy. We report that broad-spectrum inhibition of purinergic (P2) receptors using suramin blocked eHACSs and restored vasodilatory neurovascular coupling after subarachnoid hemorrhage. Importantly, eHACSs were also abolished using a cocktail of inhibitors targeting Gq-coupled P2Y receptors. Further, activation of P2Y receptors in brain slices from un-operated animals triggered high-amplitude Ca2+ events resembling eHACSs and disrupted neurovascular coupling. Neither tetrodotoxin nor bafilomycin A1 affected eHACSs suggesting that purine nucleotides are not released by ongoing neurotransmission and/or vesicular release after subarachnoid hemorrhage. These results indicate that purinergic signaling via P2Y receptors contributes to subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling. PMID:27207166

Purinergic signaling triggers endfoot high-amplitude Ca2+ signals and causes inversion of neurovascular coupling after subarachnoid hemorrhage.

PubMed

Pappas, Anthony C; Koide, Masayo; Wellman, George C

2016-11-01

Neurovascular coupling supports brain metabolism by matching focal increases in neuronal activity with local arteriolar dilation. Previously, we demonstrated that an emergence of spontaneous endfoot high-amplitude Ca 2+ signals (eHACSs) caused a pathologic shift in neurovascular coupling from vasodilation to vasoconstriction in brain slices obtained from subarachnoid hemorrhage model animals. Extracellular purine nucleotides (e.g., ATP) can trigger astrocyte Ca 2+ oscillations and may be elevated following subarachnoid hemorrhage. Here, the role of purinergic signaling in subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling was examined by imaging parenchymal arteriolar diameter and astrocyte Ca 2+ signals in rat brain slices using two-photon fluorescent and infrared-differential interference contrast microscopy. We report that broad-spectrum inhibition of purinergic (P2) receptors using suramin blocked eHACSs and restored vasodilatory neurovascular coupling after subarachnoid hemorrhage. Importantly, eHACSs were also abolished using a cocktail of inhibitors targeting G q -coupled P2Y receptors. Further, activation of P2Y receptors in brain slices from un-operated animals triggered high-amplitude Ca 2+ events resembling eHACSs and disrupted neurovascular coupling. Neither tetrodotoxin nor bafilomycin A1 affected eHACSs suggesting that purine nucleotides are not released by ongoing neurotransmission and/or vesicular release after subarachnoid hemorrhage. These results indicate that purinergic signaling via P2Y receptors contributes to subarachnoid hemorrhage-induced eHACSs and inversion of neurovascular coupling. © The Author(s) 2016.

Evaluation of slice accelerations using multiband echo planar imaging at 3 Tesla

PubMed Central

Xu, Junqian; Moeller, Steen; Auerbach, Edward J.; Strupp, John; Smith, Stephen M.; Feinberg, David A.; Yacoub, Essa; Uğurbil, Kâmil

2013-01-01

We evaluate residual aliasing among simultaneously excited and acquired slices in slice accelerated multiband (MB) echo planar imaging (EPI). No in-plane accelerations were used in order to maximize and evaluate achievable slice acceleration factors at 3 Tesla. We propose a novel leakage (L-) factor to quantify the effects of signal leakage between simultaneously acquired slices. With a standard 32-channel receiver coil at 3 Tesla, we demonstrate that slice acceleration factors of up to eight (MB = 8) with blipped controlled aliasing in parallel imaging (CAIPI), in the absence of in-plane accelerations, can be used routinely with acceptable image quality and integrity for whole brain imaging. Spectral analyses of single-shot fMRI time series demonstrate that temporal fluctuations due to both neuronal and physiological sources were distinguishable and comparable up to slice-acceleration factors of nine (MB = 9). The increased temporal efficiency could be employed to achieve, within a given acquisition period, higher spatial resolution, increased fMRI statistical power, multiple TEs, faster sampling of temporal events in a resting state fMRI time series, increased sampling of q-space in diffusion imaging, or more quiet time during a scan. PMID:23899722

Sensitivity analysis of brain morphometry based on MRI-derived surface models

NASA Astrophysics Data System (ADS)

Klein, Gregory J.; Teng, Xia; Schoenemann, P. T.; Budinger, Thomas F.

1998-07-01

Quantification of brain structure is important for evaluating changes in brain size with growth and aging and for characterizing neurodegeneration disorders. Previous quantification efforts using ex vivo techniques suffered considerable error due to shrinkage of the cerebrum after extraction from the skull, deformation of slices during sectioning, and numerous other factors. In vivo imaging studies of brain anatomy avoid these problems and allow repetitive studies following progression of brain structure changes due to disease or natural processes. We have developed a methodology for obtaining triangular mesh models of the cortical surface from MRI brain datasets. The cortex is segmented from nonbrain tissue using a 2D region-growing technique combined with occasional manual edits. Once segmented, thresholding and image morphological operations (erosions and openings) are used to expose the regions between adjacent surfaces in deep cortical folds. A 2D region- following procedure is then used to find a set of contours outlining the cortical boundary on each slice. The contours on all slices are tiled together to form a closed triangular mesh model approximating the cortical surface. This model can be used for calculation of cortical surface area and volume, as well as other parameters of interest. Except for the initial segmentation of the cortex from the skull, the technique is automatic and requires only modest computation time on modern workstations. Though the use of image data avoids many of the pitfalls of ex vivo and sectioning techniques, our MRI-based technique is still vulnerable to errors that may impact the accuracy of estimated brain structure parameters. Potential inaccuracies include segmentation errors due to incorrect thresholding, missed deep sulcal surfaces, falsely segmented holes due to image noise and surface tiling artifacts. The focus of this paper is the characterization of these errors and how they affect measurements of cortical surface area and volume.

Impacts of simultaneous multislice acquisition on sensitivity and specificity in fMRI.

PubMed

Risk, Benjamin B; Kociuba, Mary C; Rowe, Daniel B

2018-05-15

Simultaneous multislice (SMS) imaging can be used to decrease the time between acquisition of fMRI volumes, which can increase sensitivity by facilitating the removal of higher-frequency artifacts and boosting effective sample size. The technique requires an additional processing step in which the slices are separated, or unaliased, to recover the whole brain volume. However, this may result in signal "leakage" between aliased locations, i.e., slice "leakage," and lead to spurious activation (decreased specificity). SMS can also lead to noise amplification, which can reduce the benefits of decreased repetition time. In this study, we evaluate the original slice-GRAPPA (no leak block) reconstruction algorithm and acceleration factor (AF = 8) used in the fMRI data in the young adult Human Connectome Project (HCP). We also evaluate split slice-GRAPPA (leak block), which can reduce slice leakage. We use simulations to disentangle higher test statistics into true positives (sensitivity) and false positives (decreased specificity). Slice leakage was greatly decreased by split slice-GRAPPA. Noise amplification was decreased by using moderate acceleration factors (AF = 4). We examined slice leakage in unprocessed fMRI motor task data from the HCP. When data were smoothed, we found evidence of slice leakage in some, but not all, subjects. We also found evidence of SMS noise amplification in unprocessed task and processed resting-state HCP data. Copyright © 2018 Elsevier Inc. All rights reserved.

Comparison of push-out bond strengths of Resilon with three different sealers.

PubMed

Stiegemeier, Danielle; Baumgartner, J Craig; Ferracane, Jack

2010-02-01

The purpose of this study was to evaluate the push-out bond strengths of different obturating materials. Forty single-rooted human extracted teeth were used in this study. The teeth were instrumented and irrigated by using 5.25% NaOCl, 15% ethylenediaminetetraacetic acid, and sterile water. The teeth were then filled with Resilon/RealSeal, Resilon/RealSeal SE, Resilon/MetaSeal , or gutta-percha/Kerr EWT sealer. The roots were then sectioned into 1-mm-thick slices and subjected to vertical loading to displace the obturating material toward the coronal side of the slice. The bond strength was then calculated and subjected to statistical analysis. Slices were examined by using a stereomicroscope at 30x to determine the mode of failure. The mean push-out bond strengths were as follows: Resilon/RealSeal, 1.45 +/- 0.99 MPa; RealSeal SE, 0.88 +/- 0.49 MPa; Resilon/MetaSeal, 2.41 +/- 1.7 MPa; and gutta-percha/Kerr EWT sealer, 2.32 +/- 0.74 MPa. The push-out bond strengths of Resilon/MetaSeal and gutta-percha/Kerr EWT were significantly (P < .05) higher than either Resilon/RealSeal or Resilon/RealSeal SE. Resilon/MetaSeal and gutta-percha/Kerr EWT did not differ significantly. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

REGULATION OF BRAIN-DERIVED NEUROTROPHIC FACTOR MESSENGER RNA LEVELS IN AVIAN HYPOTHALAMIC SLICE CULTURES. (R825294)

EPA Science Inventory

Mechanisms regulating the expression of brain-derived neurotrophic factor, a member of the neurotrophin family, have been extensively studied in the rat cerebral cortex, hippocampus and cerebellum. In contrast, little is known regarding the regulation of this growth factor in ...

Excitatory action of GABA on immature neurons is not due to absence of ketone bodies metabolites or other energy substrates.

PubMed

Ben-Ari, Yehezkel; Tyzio, Roman; Nehlig, Astrid

2011-09-01

Brain slices incubated with glucose have provided most of our knowledge on cellular, synaptic, and network driven mechanisms. It has been recently suggested that γ-aminobutyric acid (GABA) excites neonatal neurons in conventional glucose-perfused slices but not when ketone bodies metabolites, pyruvate, and/or lactate are added, suggesting that the excitatory actions of GABA are due to energy deprivation when glucose is the sole energy source. In this article, we review the vast number of studies that show that slices are not energy deprived in glucose-containing medium, and that addition of other energy substrates at physiologic concentrations does not alter the excitatory actions of GABA on neonatal neurons. In contrast, lactate, like other weak acids, can produce an intracellular acidification that will cause a reduction of intracellular chloride and a shift of GABA actions. The effects of high concentrations of lactate, and particularly of pyruvate (4-5 mm), as used are relevant primarily to pathologic conditions; these concentrations not being found in the brain in normal "control" conditions. Slices in glucose-containing medium may not be ideal, but additional energy substrates neither correspond to physiologic conditions nor alter GABA actions. In keeping with extensive observations in a wide range of animal species and brain structures, GABA depolarizes immature neurons and the reduction of the intracellular concentration of chloride ([Cl(-)](i)) is a basic property of brain maturation that has been preserved throughout evolution. In addition, this developmental sequence has important clinical implications, notably concerning the higher incidence of seizures early in life and their long-lasting deleterious sequels. Immature neurons have difficulties exporting chloride that accumulates during seizures, leading to permanent increase of [Cl(-)](i) that converts the inhibitory actions of GABA to excitatory and hampers the efficacy of GABA-acting antiepileptic drugs. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

A repetitive intracortical microstimulation pattern induces long-lasting synaptic depression in brain slices of the rat primary somatosensory cortex.

PubMed

Heusler, P; Cebulla, B; Boehmer, G; Dinse, H R

2000-12-01

Repetitive intracortical microstimulation (ICMS) applied to the rat primary somatosensory cortex (SI) in vivo was reported to induce reorganization of receptive fields and cortical maps. The present study was designed to examine the effect of such an ICMS pattern applied to layer IV of brain slices containing SI on the efficacy of synaptic input to layer II/III. Effects of ICMS on the synaptic strength was quantified for the first synaptic component (s1) of cortical field potentials (FPs) recorded from layer II/III of SI. FPs were evoked by stimulation in layer IV. The pattern of ICMS was identical to that used in vivo. However, stimulation intensity had to be raised to induce an alteration of synaptic strength. In brain slices superfused with standard ACSF, repetitive ICMS induced a short-lasting (60 min) reduction of the amplitude (-37%) and the slope (-61%) of s1 evoked from the ICMS site, while the amplitude and the slope of s1 evoked from a control stimulation site in cortical layer IV underwent a slow onset increase (13% and 50%, respectively). In brain slices superfused with ACSF containing 1.25 microM bicuculline, ICMS induced an initial strong reduction of the amplitude (-50%) and the slope (-79%) of s1 evoked from the ICMS site. These effects decayed to a sustained level of depression by -30% (amplitude) and -60% (slope). In contrast to experiments using standard ACSF, s1 evoked from the control site was not affected by ICMS. The presynaptic volley was not affected in either of the two groups of experiments. A conventional high frequency stimulation (HFS) protocol induced input-specific long-term potentiation (LTP) of the amplitude and slope of s1 (25% and 76%, respectively). Low frequency stimulation (LFS) induced input-specific long-term depression (LTD) of the amplitude and slope of s1 (24% and 30%, respectively). Application of common forms of conditioning stimulation (HFS and LFS) resulted in LTP or LTD of s1, indicating normal susceptibility of the brain slices studied to the induction of common forms of synaptic plasticity. Therefore, the effects of repetitive ICMS on synaptic FP components were considered ICMS-specific forms of short-lasting (standard ACSF) or long-lasting synaptic depression (ACSF containing bicuculline), the latter resembling neocortical LTD. Results of this study suggest that synaptic depression of excitatory mechanisms are involved in the cortical reorganization induced by repetitive ICMS in vivo. An additional contribution of an ICMS-induced modification of inhibitory mechanisms to cortical reorganization is discussed.

Interactive Medical Volume Visualization for Surgical Operations

DTIC Science & Technology

2001-10-25

the preprocessing and processing stages, related medical brain tissues, which are skull, white matter, gray matter and pathology ( tumor ), are segmented ...from 12 or 16 bit data depths. NMR segmentation plays an important role in our work, because, classifying brain tissues from NMR slices requires an...performing segmentation of brain structures. Our segmentation process uses Self Organizing Feature Maps (SOFM) [12]. In SOM, on the contrary to Feedback

Graph-based retrospective 4D image construction from free-breathing MRI slice acquisitions

NASA Astrophysics Data System (ADS)

Tong, Yubing; Udupa, Jayaram K.; Ciesielski, Krzysztof C.; McDonough, Joseph M.; Mong, Andrew; Campbell, Robert M.

2014-03-01

4D or dynamic imaging of the thorax has many potential applications [1, 2]. CT and MRI offer sufficient speed to acquire motion information via 4D imaging. However they have different constraints and requirements. For both modalities both prospective and retrospective respiratory gating and tracking techniques have been developed [3, 4]. For pediatric imaging, x-ray radiation becomes a primary concern and MRI remains as the de facto choice. The pediatric subjects we deal with often suffer from extreme malformations of their chest wall, diaphragm, and/or spine, as such patient cooperation needed by some of the gating and tracking techniques are difficult to realize without causing patient discomfort. Moreover, we are interested in the mechanical function of their thorax in its natural form in tidal breathing. Therefore free-breathing MRI acquisition is the ideal modality of imaging for these patients. In our set up, for each coronal (or sagittal) slice position, slice images are acquired at a rate of about 200-300 ms/slice over several natural breathing cycles. This produces typically several thousands of slices which contain both the anatomic and dynamic information. However, it is not trivial to form a consistent and well defined 4D volume from these data. In this paper, we present a novel graph-based combinatorial optimization solution for constructing the best possible 4D scene from such data entirely in the digital domain. Our proposed method is purely image-based and does not need breath holding or any external surrogates or instruments to record respiratory motion or tidal volume. Both adult and children patients' data are used to illustrate the performance of the proposed method. Experimental results show that the reconstructed 4D scenes are smooth and consistent spatially and temporally, agreeing with known shape and motion of the lungs.

A method for smoothing segmented lung boundary in chest CT images

NASA Astrophysics Data System (ADS)

Yim, Yeny; Hong, Helen

2007-03-01

To segment low density lung regions in chest CT images, most of methods use the difference in gray-level value of pixels. However, radiodense pulmonary vessels and pleural nodules that contact with the surrounding anatomy are often excluded from the segmentation result. To smooth lung boundary segmented by gray-level processing in chest CT images, we propose a new method using scan line search. Our method consists of three main steps. First, lung boundary is extracted by our automatic segmentation method. Second, segmented lung contour is smoothed in each axial CT slice. We propose a scan line search to track the points on lung contour and find rapidly changing curvature efficiently. Finally, to provide consistent appearance between lung contours in adjacent axial slices, 2D closing in coronal plane is applied within pre-defined subvolume. Our method has been applied for performance evaluation with the aspects of visual inspection, accuracy and processing time. The results of our method show that the smoothness of lung contour was considerably increased by compensating for pulmonary vessels and pleural nodules.

Effects of orthopedic maxillary expansion on nasal cavity size in growing subjects: a low dose computer tomography clinical trial.

PubMed

Cordasco, Giancarlo; Nucera, Riccardo; Fastuca, Rosamaria; Matarese, Giovanni; Lindauer, Steven J; Leone, Pietro; Manzo, Paolo; Martina, Roberto

2012-11-01

The aim of this retrospective clinical trial was to evaluate the effects of rapid maxillary expansion on skeletal nasal cavity size in growing subjects by use of low dose computer tomography. Eight Caucasian children (three male; five female) with a mean age of 9.7 years (SD±1.41) were the final sample of this research that underwent palatal expansion as a first phase of orthodontic treatment. The maxillary expander was banded to the upper first molars and was activated according a rapid maxillary expansion protocol. Low-dose computer tomography examinations of maxilla and of the low portion of nasal cavity were performed before inserting the maxillary expander (T0) and at the end of retention (T1), 7 months later. A low-dose computer tomography protocol was applied during the exams. Image processing was achieved in 3 steps: reslicing; dental and skeletal measurements; skeletal nasal volume computing. A set of reproducible skeletal and dental landmarks were located in the coronal passing through the first upper right molar furcation. Using the landmarks, a set of transverse linear measurements were identified to estimate maximum nasal width and nasal floor width. To compute the nasal volume the lower portion of the nasal cavity was set as region of interest. Nasal volume was calculated using a set of coronal slices. In each coronal slice, the cortical bone of the nasal cavity was identified and selected with a segmentation technique. Dependent t-tests were used to evaluate changes due to expansion. For all tests, a significance level of P<0.05 was used. Rapid maxillary expansion produced significant increases of linear transverse skeletal measurements, these increments were bigger in the lower portion of the nasal cavities: nasal floor width (+3.15 mm; SD ± 0.99), maximum nasal width (+2.47 mm; SD ± 0.99). Rapid maxillary expansion produced significant increment of the total nasal volume (+1.27 cm(3) ± SD 0.65). The anterior volume increase was 0.58 cm(3) while the posterior one was 0.69 cm(3). In growing subjects RME is able to significantly enlarge the dimension of nasal cavity. The increment is bigger in the lower part of the nose and equally distributed between the anterior e the posterior part of the nasal cavity. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Acetylcholine Mediates a Slow Synaptic Potential in Hippocampal Pyramidal Cells

NASA Astrophysics Data System (ADS)

Cole, A. E.; Nicoll, R. A.

1983-09-01

The hippocampal slice preparation was used to study the role of acetylcholine as a synaptic transmitter. Bath-applied acetylcholine had three actions on pyramidal cells: (i) depolarization associated with increased input resistance, (ii) blockade of calcium-activated potassium responses, and (iii) blockade of accommodation of cell discharge. All these actions were reversed by the muscarinic antagonist atropine. Stimulation of sites in the slice known to contain cholinergic fibers mimicked all the actions. Furthermore, these evoked synaptic responses were enhanced by the cholinesterase inhibitor eserine and were blocked by atropine. These findings provide electrophysiological support for the role of acetylcholine as a synaptic transmitter in the brain and demonstrate that nonclassical synaptic responses involving the blockade of membrane conductances exist in the brain.

Evaluation of time required for recontamination of coronally sealed canals medicated with calcium hydroxide and chlorhexidine.

PubMed

Gomes, B P F A; Sato, E; Ferraz, C C R; Teixeira, F B; Zaia, A A; Souza-Filho, F J

2003-09-01

To determine in vitro the time required for recontamination of coronally sealed canals medicated with either calcium hydroxide (CaOH2), 2% chlorhexidine gel (CG) or with a combination of both. Eighty intact, caries-free, premolar teeth with straight roots and mature apices were selected for the study. After biomechanical preparation of 75 teeth, they were randomly divided into nine groups according to the intracanal medicament and the coronal seal with 'Intermediate Restorative Material' (IRM) as follows: (i) 10 teeth medicated with CG, coronally unsealed; (ii) 10 teeth medicated with CaOH2, coronally unsealed; (iii) 10 teeth medicated with CaOH2 + CG, coronally unsealed; (iv) 10 teeth medicated with CG + coronal seal; (v) 10 teeth medicated with CaOH2 + coronal seal; (vi) 10 teeth medicated with CG + CaOH2 + coronal seal; (vii) 10 teeth without intracanal medicament and coronally sealed; (viii) 5 teeth without intracanal medicament and coronally unsealed, used as the positive control group (PC); (ix) 5 teeth with intact crowns used as the negative control group (NC). Glass flasks were filled with Brain Heart Infusion broth (BHI), so that only the root apex was in contact with the broth, while the crown was immersed in human saliva + BHI (3:1). The flasks were then incubated at 37 degrees C in an atmosphere of 10% CO2, and microbial growth was checked daily. All specimens of the PC showed contamination within 1 day of incubation, while the NC showed no evidence of broth turbidity. Recontamination was detected after an average time of 3.7 days in the unsealed canals medicated with CG, 1.8 days in the group medicated with CaOH2 and 2.6 days in the group medicated with CaOH2 + CG. When the crowns were sealed with IRM, recontamination was detected within 13.5 days in the canals medicated with CG, after 17.2 days in the group medicated with CaOH2 and after 11.9 days in the group medicated with CG + CaOH2. The group with no medication, but sealed with IRM, showed recontamination after 8.7 days. There were statistically significant differences between the teeth with or without coronal seal (P<0.05). The coronal seal delayed but did not prevent leakage of microorganisms. There was no difference between the various medicaments.

Clinical feasibility of simultaneous multi-slice imaging with blipped-CAIPI for diffusion-weighted imaging and diffusion-tensor imaging of the brain.

PubMed

Yokota, Hajime; Sakai, Koji; Tazoe, Jun; Goto, Mariko; Imai, Hiroshi; Teramukai, Satoshi; Yamada, Kei

2017-12-01

Background Simultaneous multi-slice (SMS) imaging is starting to be used in clinical situation, although evidence of clinical feasibility is scanty. Purpose To prospectively assess the clinical feasibility of SMS diffusion-weighted imaging (DWI) and diffusion-tensor imaging (DTI) with blipped-controlled aliasing in parallel imaging for brain lesions. Material and Methods The institutional review board approved this study. This study included 156 hyperintense lesions on DWI from 32 patients. A slice acceleration factor of 2 was applied for SMS scans, which allowed shortening of the scan time by 41.3%. The signal-to-noise ratio (SNR) was calculated for brain tissue of a selected slice. The contrast-to-noise ratio (CNR), apparent diffusion coefficient (ADC), and fractional anisotropy (FA) were calculated in 36 hyperintense lesions with a diameter of three pixels or more. Visual assessment was performed for all 156 lesions. Tractography of the corticospinal tract of 29 patients was evaluated. The number of tracts and averaged tract length were used for quantitative analysis, and visual assessment was evaluated by grading. Results The SMS scan showed no bias and acceptable 95% limits of agreement compared to conventional scans in SNR, CNR, and ADC on Bland-Altman analyses. Only FA of the lesions was higher in the SMS scan by 9% ( P = 0.016), whereas FA of the surrounding tissues was similar. Quantitative analysis of tractography showed similar values. Visual assessment of DWI hyperintense lesions and tractography also resulted in comparable evaluation. Conclusion SMS imaging was clinically feasible for imaging quality and quantitative values compared with conventional DWI and DTI.

An organotypic slice culture model of chronic white matter injury with maturation arrest of oligodendrocyte progenitors.

PubMed

Dean, Justin M; Riddle, Art; Maire, Jennifer; Hansen, Kelly D; Preston, Marnie; Barnes, Anthony P; Sherman, Larry S; Back, Stephen A

2011-07-05

CNS myelination disturbances commonly occur in chronic white matter lesions in neurodevelopmental and adult neurological disorders. Recent studies support that myelination failure can involve a disrupted cellular repair mechanism where oligodendrocyte (OL) progenitor cells (OPCs) proliferate in lesions with diffuse astrogliosis, but fail to fully differentiate to mature myelinating OLs. There are no in vitro models that reproduce these features of myelination failure. Forebrain coronal slices from postnatal day (P) 0.5/1 rat pups were cultured for 1, 5, or 9 days in vitro (DIV). Slices rapidly exhibited diffuse astrogliosis and accumulation of the extracellular matrix glycosaminoglycan hyaluronan (HA), an inhibitor of OPC differentiation and re-myelination. At 1 DIV ~1.5% of Olig2+ OLs displayed caspase-3 activation, which increased to ~11.5% by 9 DIV. At 1 DIV the density of PDGFRα+ and PDGFRα+/Ki67+ OPCs were significantly elevated compared to 0 DIV (P < 0.01). Despite this proliferative response, at 9 DIV ~60% of white matter OLs were late progenitors (preOLs), compared to ~7% in the postnatal day 10 rat (P < 0.0001), consistent with preOL maturation arrest. Addition of HA to slices significantly decreased the density of MBP+ OLs at 9 DIV compared to controls (217 ± 16 vs. 328 ± 17 cells/mm2, respectively; P = 0.0003), supporting an inhibitory role of HA in OL lineage progression in chronic lesions. Diffuse white matter astrogliosis and early OPC proliferation with impaired OL maturation were reproduced in this model of myelination failure. This system may be used to define mechanisms of OPC maturation arrest and myelination failure related to astrogliosis and HA accumulation.

3-D in vivo brain tumor geometry study by scaling analysis

NASA Astrophysics Data System (ADS)

Torres Hoyos, F.; Martín-Landrove, M.

2012-02-01

A new method, based on scaling analysis, is used to calculate fractal dimension and local roughness exponents to characterize in vivo 3-D tumor growth in the brain. Image acquisition was made according to the standard protocol used for brain radiotherapy and radiosurgery, i.e., axial, coronal and sagittal magnetic resonance T1-weighted images, and comprising the brain volume for image registration. Image segmentation was performed by the application of the k-means procedure upon contrasted images. We analyzed glioblastomas, astrocytomas, metastases and benign brain tumors. The results show significant variations of the parameters depending on the tumor stage and histological origin.

Neurotransmitter agonists inhibit inositol phosphate formation in the brain of bupropione-treated rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butler, P.D.; Hungund, B.; Suckow, R.

1986-03-05

Bupropione is a chemically unique antidepressant whose mechanism of action is not known. In this study they have evaluated the effect of chronic treatment with bupropione on the receptor-mediated release of inositol phosphates (IP) from brain slices in rats. Animals were implanted with Alzet osmotic pumps that delivered bupropione at a constant rate (40mg/kg/day) for 2 weeks. Cross-chopped slices of cerebral cortex from control and drug-treated rats were prelabelled with myo-/sup 3/H-inositol in HEPES buffer containing 11 mM LiCl. Accumulation of IP was measured in the presence and absence of the following agonists: Carbamylcholine (100..mu..m); norepinephrine (5..mu..M) and serotonin (10..mu..M).more » All agonists stimulated release of IP from slices of control animals but appeared to inhibit IP release in bupropione-treated rats. These results indicate that a phospholipase C inhibitor may appear following the activation of this enzyme by the agonist, and that the agonist-induced formation of the apparent inhibitor may be markedly enhanced after treatment with bupropione.« less

Intracranial Volume and Whole Brain Volume in Infants With Unicoronal Craniosynostosis

PubMed Central

Hill, Cheryl A.; Vaddi, S.; Moffitt, Amanda; Kane, A.A.; Marsh, Jeffrey L.; Panchal, Jayesh; Richtsmeier, Joan T.; Aldridge, Kristina

2011-01-01

Objective Craniosynostosis has been hypothesized to result in alterations of the brain and cerebral blood flow due to reduced intracranial volume, potentially leading to cognitive deficits. In this study we test the hypothesis that intracranial volume and whole brain volume in infants with unilateral coronal synostosis differs from those in unaffected infants. Design Our study sample consists of magnetic resonance images acquired from 7- to 72-week-old infants with right unilateral coronal synostosis prior to surgery (n = 10) and age-matched unaffected infants (n = 10). We used Analyze 9.0 software to collect three cranial volume measurements. We used nonparametric tests to determine whether the three measures differ between the two groups. Correlations were calculated between age and the three volume measures in each group to determine whether the growth trajectory of the measurements differ between children with right unicoronal synostosis and unaffected infants. Results Our results show that the three volume measurements are not reduced in infants with right unicoronal synostosis relative to unaffected children. Correlation analyses between age and various volume measures show similar correlations in infants with right unicoronal synostosis compared with unaffected children. Conclusions Our results show that the relationship between brain size and intracranial size in infants with right unicoronal synostosis is similar to that in unaffected children, suggesting that reduced intracranial volume is not responsible for alterations of the brain in craniosynostosis. PMID:20815706

WE-G-BRD-01: A Data-Driven 4D-MRI Motion Model to Estimate Full Field-Of-View Abdominal Motion From 2D Image Navigators During MR-Linac Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stemkens, B; Tijssen, RHN; Denis de Senneville, B Denis

2015-06-15

Purpose: To estimate full field-of-view abdominal respiratory motion from fast 2D image navigators using a 4D-MRI based motion model. This will allow for radiation dose accumulation mapping during MR-Linac treatment. Methods: Experiments were conducted on a Philips Ingenia 1.5T MRI. First, a retrospectively ordered 4D-MRI was constructed using 3D transient-bSSFP with radial in-plane sampling. Motion fields were calculated through 3D non-rigid registration. From these motion fields a PCA-based abdominal motion model was constructed and used to warp a 3D reference volume to fast 2D cine-MR image navigators that can be used for real-time tracking. To test this procedure, a time-seriesmore » consisting of two interleaved orthogonal slices (sagittal and coronal), positioned on the pancreas or kidneys, were acquired for 1m38s (dynamic scan-time=0.196ms), during normal, shallow, or deep breathing. The coronal slices were used to update the optimal weights for the first two PCA components, in order to warp the 3D reference image and construct a dynamic 4D-MRI time-series. The interleaved sagittal slices served as an independent measure to test the model’s accuracy and fit. Spatial maps of the root-mean-squared error (RMSE) and histograms of the motion differences within the pancreas and kidneys were used to evaluate the method. Results: Cranio-caudal motion was accurately calculated within the pancreas using the model for normal and shallow breathing with an RMSE of 1.6mm and 1.5mm and a histogram median and standard deviation below 0.2 and 1.7mm, respectively. For deep-breathing an underestimation of the inhale amplitude was observed (RMSE=4.1mm). Respiratory-induced antero-posterior and lateral motion were correctly mapped (RMSE=0.6/0.5mm). Kidney motion demonstrated good motion estimation with RMSE-values of 0.95 and 2.4mm for the right and left kidney, respectively. Conclusion: We have demonstrated a method that can calculate dynamic 3D abdominal motion in a large volume, while acquiring real-time cine-MR images for MR-guided radiotherapy.« less

Distribution of lacosamide in the rat brain assessed by in vitro slice technique.

PubMed

Gáll, Zsolt; Vancea, Szende

2018-01-01

Lacosamide is a newer anticonvulsant and is the only one that enhances the slow inactivation of voltage gated sodium channels. It is also claimed to have disease-modifying potential, but its pharmacokinetic properties have been much less discussed in the literature. In rats, lacosamide shows restricted distribution to tissues, and the brain-to-plasma partition coefficient (K p ) is only 0.553. In this study, the brain disposition of lacosamide was evaluated in rat brains, and its neuropharmacokinetic parameters (i.e., protein binding and intracellular accumulation) were assessed using in vitro methods. Brain slice experiments and brain homogenate binding studies were performed for several drugs acting on the central nervous system, and drugs were assayed by using a liquid chromatography-mass spectrometry system. By applying a combined approach, it was found that (1) the unbound volume of distribution in the brain for lacosamide (V u,brain  = 1.37) was lower than that of other classical anticonvulsants; (2) the unbound fraction of lacosamide in the brain (0.899) was slightly lower than its unbound fraction in plasma (0.96); (3) the unbound intracellular-to-extracellular concentration ratio of lacosamide was 1.233, meaning that lacosamide was accumulated in the intracellular space because of its physicochemical properties and zwitterionic structure; and (4) the unbound brain-to-plasma concentration ratio of lacosamide was lower than the total brain-to-plasma concentration ratio (K p,uu,brain  = 0.42 vs. K p  = 0.553). In conclusion, the limited brain distribution of lacosamide is not related to its nonspecific protein-binding capacity; rather, an active transport mechanism across the blood-brain barrier may be involved, which reduces the anticonvulsant and/or antiepileptogenic actions of this drug.

Rapid brain MRI acquisition techniques at ultra-high fields

PubMed Central

Setsompop, Kawin; Feinberg, David A.; Polimeni, Jonathan R.

2017-01-01

Ultra-high-field MRI provides large increases in signal-to-noise ratio as well as enhancement of several contrast mechanisms in both structural and functional imaging. Combined, these gains result in a substantial boost in contrast-to-noise ratio that can be exploited for higher spatial resolution imaging to extract finer-scale information about the brain. With increased spatial resolution, however, is a concurrent increased image encoding burden that can cause unacceptably long scan times for structural imaging and slow temporal sampling of the hemodynamic response in functional MRI—particularly when whole-brain imaging is desired. To address this issue, new directions of imaging technology development—such as the move from conventional 2D slice-by-slice imaging to more efficient Simultaneous MultiSlice (SMS) or MultiBand imaging (which can be viewed as “pseudo-3D” encoding) as well as full 3D imaging—have provided dramatic improvements in acquisition speed. Such imaging paradigms provide higher SNR efficiency as well as improved encoding efficiency. Moreover, SMS and 3D imaging can make better use of coil sensitivity information in multi-channel receiver arrays used for parallel imaging acquisitions through controlled aliasing in multiple spatial directions. This has enabled unprecedented acceleration factors of an order of magnitude or higher in these imaging acquisition schemes, with low image artifact levels and high SNR. Here we review the latest developments of SMS and 3D imaging methods and related technologies at ultra-high field for rapid high-resolution functional and structural imaging of the brain. PMID:26835884

Quantitative measurements of regional glucose utilization and rate of valine incorporation into proteins by double-tracer autoradiography in the rat brain tumor model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirikae, M.; Diksic, M.; Yamamoto, Y.L.

1989-02-01

We examined the rate of glucose utilization and the rate of valine incorporation into proteins using 2-(/sup 18/F)fluoro-2-deoxyglucose and L-(1-14C)-valine in a rat brain tumor model by quantitative double-tracer autoradiography. We found that in the implanted tumor the rate of valine incorporation into proteins was about 22 times and the rate of glucose utilization was about 1.5 times that in the contralateral cortex. (In the ipsilateral cortex, the tumor had a profound effect on glucose utilization but no effect on the rate of valine incorporation into proteins.) Our findings suggest that it is more useful to measure protein synthesis thanmore » glucose utilization to assess the effectiveness of antitumor agents and their toxicity to normal brain tissue. We compared two methods to estimate the rate of valine incorporation: kinetic (quantitation done using an operational equation and the average brain rate coefficients) and washed slices (unbound labeled valine removed by washing brain slices in 10% trichloroacetic acid). The results were the same using either method. It would seem that the kinetic method can thus be used for quantitative measurement of protein synthesis in brain tumors and normal brain tissue using (/sup 11/C)-valine with positron emission tomography.« less

Significant glial alterations in response to iron loading in a novel organotypic hippocampal slice culture model

PubMed Central

Healy, Sinead; McMahon, Jill; Owens, Peter; FitzGerald, Una

2016-01-01

Aberrant iron deposition in the brain is associated with neurodegenerative disorders including Multiple Sclerosis, Alzheimer’s disease and Parkinson’s disease. To study the collective response to iron loading, we have used hippocampal organotypic slices as a platform to develop a novel ex vivo model of iron accumulation. We demonstrated differential uptake and toxicity of iron after 12 h exposure to 10 μM ferrous ammonium sulphate, ferric citrate or ferrocene. Having established the supremacy of ferrocene in this model, the cultures were then loaded with 0.1–100 μM ferrocene for 12 h. One μM ferrocene exposure produced the maximal 1.6-fold increase in iron compared with vehicle. This was accompanied by a 1.4-fold increase in ferritin transcripts and mild toxicity. Using dual-immunohistochemistry, we detected ferritin in oligodendrocytes, microglia, but rarely in astrocytes and never in neurons in iron-loaded slice cultures. Moreover, iron loading led to a 15% loss of olig2-positive cells and a 16% increase in number and greater activation of microglia compared with vehicle. However, there was no appreciable effect of iron loading on astrocytes. In what we believe is a significant advance on traditional mono- or dual-cultures, our novel ex vivo slice-culture model allows characterization of the collective response of brain cells to iron-loading. PMID:27808258

Studies on the neuroprotective action of kynurenine mono-oxygenase inhibitors in post-ischemic brain damage.

PubMed

Moroni, Flavio; Carpenedo, Raffaella; Cozzi, Andrea; Meli, Elena; Chiarugi, Alberto; Pellegrini-Giampietro, Domenico E

2003-01-01

Kynurenine 3-mono-oxygenase (KMO) inhibitors facilitate kynurenic acid (KYNA) neosynthesis and reduce the formation of 3OH-kynurenine (3-HK) and quinolinic acid (QUIN). They also attenuate post-ischemic brain damage and decrease glutamate (Glu) content in brain extracellular spaces. To investigate KMO mechanism(s) of neuroprotection, we performed experiments in gerbils subjected to bilateral carotid occlusion and in organotypic rat hippocampal slice cultures exposed to oxygen and glucose deprivation (OGD). In gerbils, direct application of KYNA (100 nM, through reverse microdialysis in the hippocampus) completely prevented the increase in Glu output induced by transient (5 min) occlusion of the carotids. In rat hippocampal slices exposed for 30 min to OGD, KMO inhibitors (m-nitrobenzoyl)-alanine (mNBA, 30-100 microM) or 3,4-dimethoxy-[-N-4-(nitrophenyl)thiazol-2yl]-benzenesulfonamide (Ro 61-8048, 1-10 microM) reduced post-ischemic neuronal death and increased KYNA concentrations in the incubation medium. KYNA may antagonize glycineb or alpha7 nicotinic acetylcholine receptors but the concentrations in the incubation medium never reached values that could efficiently antagonize receptor function. On the contrary, 3-HK (1-10 microM) added to slices exposed to OGD in the presence of KMO inhibitors completely prevented the neuroprotective effects of the inhibitors. Our findings suggest that KMO inhibitors reduce OGD-induced pyramidal cell death by decreasing 3-HK (and possibly QUIN) synthesis.

Focal macromolecule delivery in neuronal tissue using simultaneous pressure ejection and local electroporation

PubMed Central

Barker, Matthew; Billups, Brian; Hamann, Martine

2009-01-01

Electroporation creates transient pores in the plasma membrane to introduce macromolecules within a cell or cell population. Generally, electrical pulses are delivered between two electrodes separated from each other, making electroporation less likely to be localised. We have developed a new device combining local pressure ejection with local electroporation through a double-barrelled glass micropipette to transfer impermeable macromolecules in brain slices or in cultured HEK293 cells. The design achieves better targeting of the site of pressure ejection with that of electroporation. With this technique, we have been able to limit the delivery of propidium iodide or dextran amine within areas of 100–200 μm diameter. We confirm that local electroporation is transient and show that when combined with pressure ejection, it allows local transfection of EGFP plasmids within HEK293 cells or within cerebellar and hippocampal slice cultures. We further show that local electroporation is less damaging when compared to global electroporation using two separate electrodes. Focal delivery of dextran amine dyes within trapezoid body fibres allowed tracing axonal tracts within brainstem slices, enabling the study of identified calyx of Held presynaptic terminals in living brain tissue. This labelling method can be used to target small nuclei in neuronal tissue and is generally applicable to the study of functional synaptic connectivity, or live axonal tracing in a variety of brain areas. PMID:19014970

Three-dimensional confocal morphometry – a new approach for studying dynamic changes in cell morphology in brain slices

PubMed Central

Chvátal, Alexandr; Anděrová, Miroslava; Kirchhoff, Frank

2007-01-01

Pathological states in the central nervous system lead to dramatic changes in the activity of neuroactive substances in the extracellular space, to changes in ionic homeostasis and often to cell swelling. To quantify changes in cell morphology over a certain period of time, we employed a new technique, three-dimensional confocal morphometry. In our experiments, performed on enhanced green fluorescent protein/glial fibrillary acidic protein astrocytes in brain slices in situ and thus preserving the extracellular microenvironment, confocal morphometry revealed that the application of hypotonic solution evoked two types of volume change. In one population of astrocytes, hypotonic stress evoked small cell volume changes followed by a regulatory volume decrease, while in the second population volume changes were significantly larger without subsequent volume regulation. Three-dimensional cell reconstruction revealed that even though the total astrocyte volume increased during hypotonic stress, the morphological changes in various cell compartments and processes were more complex than have been previously shown, including swelling, shrinking and structural rearrangement. Our data show that astrocytes in brain slices in situ during hypotonic stress display complex behaviour. One population of astrocytes is highly capable of cell volume regulation, while the second population is characterized by prominent cell swelling, accompanied by plastic changes in morphology. It is possible to speculate that these two astrocyte populations play different roles during physiological and pathological states. PMID:17488344

Effect of vitro preservation on mechanical properties of brain tissue

NASA Astrophysics Data System (ADS)

Zhang, Wei; Liu, Yi-fan; Liu, Li-fu; Niu, Ying; Ma, Jian-li; Wu, Cheng-wei

2017-05-01

To develop the protective devices for preventing traumatic brain injuries, it requires the accurate characterization of the mechanical properties of brain tissue. For this, it necessary to elucidate the effect of vitro preservation on the mechanical performance of brain tissue as usually the measurements are carried out in vitro. In this paper, the thermal behavior of brain tissue preserved for various period of time was first investigated and the mechanical properties were also measured. Both reveals the deterioration with prolonged preservation duration. The observations of brain tissue slices indicates the brain tissue experiences karyorrhexis and karyorrhexis in sequence, which accounts for the deterioration phenomena.

Application of Real-Time Fluorescent PCR for Quantitative Assessment of Neospora caninum Infections in Organotypic Slice Cultures of Rat Central Nervous System Tissue

PubMed Central

Müller, Norbert; Vonlaufen, Nathalie; Gianinazzi, Christian; Leib, Stephen L.; Hemphill, Andrew

2002-01-01

The previously described Nc5-specific PCR test for the diagnosis of Neospora caninum infections was used to develop a quantitative PCR assay which allows the determination of infection intensities within different experimental and diagnostic sample groups. The quantitative PCR was performed by using a dual fluorescent hybridization probe system and the LightCycler Instrument for online detection of amplified DNA. This assay was successfully applied for demonstrating the parasite proliferation kinetics in organotypic slice cultures of rat brain which were infected in vitro with N. caninum tachyzoites. This PCR-based method of parasite quantitation with organotypic brain tissue samples can be regarded as a novel ex vivo approach for exploring different aspects of cerebral N. caninum infection. PMID:11773124

Greater resistance and lower contribution of free radicals to hypoxic neurotoxicity in immature rat brain compared to adult brain as revealed by dynamic changes in glucose metabolism.

PubMed

Maruoka, N; Murata, T; Omata, N; Fujibayashi, Y; Waki, A; Yoshimoto, M; Yano, R; Yonekura, Y; Wada, Y

2001-01-01

Seven-day-old rat brain slices were incubated at 36C in oxygenated Krebs-Ringer solution containing [(18)F]2-fluoro-2-deoxy-D-glucose ([(18)F]FDG), and serial two-dimensional time-resolved images of [(18)F]FDG uptake by the slices were obtained. The Gjedde-Patlak graphical method was applied to the image data, and the duration limit of hypoxia loading that allowed recovery of the fractional rate constant (k3*) of [(18)F]FDG (proportional to the cerebral glucose metabolic rate) after hypoxia loading to the unloaded control level was 50 min, and MK-801 as an N-methyl-D-aspartate antagonist had neuroprotective effects, but PBN as a free radical scavenger was ineffective. In our previous study in adult (7-week-old) rat brains [Murata et al., Exp Neurol 2000, 164:269-279], the limit of the hypoxia loading time was 20 min, and both MK-801 and PBN were effective. In the immature rat brains, the ratio of aerobic glucose metabolism to the total glucose metabolism was low compared with the adult rat brains, suggesting only a slight involvement of free radicals in hypoxic neurotoxicity. These data suggest that the higher resistance of immature brains to hypoxia compared to that of adult brains is attributable to a lower involvement of free radicals due to a lower aerobic glucose metabolic rate. Copyright 2002 S. Karger AG, Basel

Blast waves from detonated military explosive reduce GluR1 and synaptophysin levels in hippocampal slice cultures✩

PubMed Central

Smith, Marquitta; Piehler, Thuvan; Benjamin, Richard; Farizatto, Karen L.; Pait, Morgan C.; Almeida, Michael F.; Ghukasyan, Vladimir V.; Bahr, Ben A.

2017-01-01

Explosives create shockwaves that cause blast-induced neurotrauma, one of the most common types of traumatic brain injury (TBI) linked to military service. Blast-induced TBIs are often associated with reduced cognitive and behavioral functions due to a variety of factors. To study the direct effects of military explosive blasts on brain tissue, we removed systemic factors by utilizing rat hippocampal slice cultures. The long-term slice cultures were briefly sealed air-tight in serum-free medium, lowered into a 37 °C water-filled tank, and small 1.7-gram assemblies of cyclotrimethylene trinitramine (RDX) were detonated 15 cm outside the tank, creating a distinct shockwave recorded at the culture plate position. Compared to control mock-treated groups of slices that received equal submerge time, 1–3 blast impacts caused a dose-dependent reduction in the AMPA receptor subunit GluR1. While only a small reduction was found in hippocampal slices exposed to a single RDX blast and harvested 1–2 days later, slices that received two consecutive RDX blasts 4 min apart exhibited a 26–40% reduction in GluR1, and the receptor subunit was further reduced by 64–72% after three consecutive blasts. Such loss correlated with increased levels of HDAC2, a histone deacetylase implicated in stress-induced reduction of glutamatergic transmission. No evidence of synaptic marker recovery was found at 72 h post-blast. The presynaptic marker synaptophysin was found to have similar susceptibility as GluR1 to the multiple explosive detonations. In contrast to the synaptic protein reductions, actin levels were unchanged, spectrin breakdown was not detected, and Fluoro-Jade B staining found no indication of degenerating neurons in slices exposed to three RDX blasts, suggesting that small, sub-lethal explosives are capable of producing selective alterations to synaptic integrity. Together, these results indicate that blast waves from military explosive cause signs of synaptic compromise without producing severe neurodegeneration, perhaps explaining the cognitive and behavioral changes in those blast-induced TBI sufferers that have no detectable neuropathology. PMID:27720798

Orthodontic decompensation in skeletal Class III malocclusion: redefining the amount of movement assessed by Cone-Beam Computed Tomography

PubMed Central

Cappellozza, José Antonio Zuega; Guedes, Fabio Pinto; Nary, Hugo; Capelozza, Leopoldino; Cardoso, Mauricio de Almeida

2015-01-01

Introduction: Cone-Beam Computed Tomography (CBCT) is essential for tridimensional planning of orthognathic surgery, as it allows visualization and evaluation of bone structures and mineralized tissues. Tomographic slices allow evaluation of tooth inclination and individualization of movement performed during preoperative decompensation. The aim of this paper was to assess maxillary and mandibular incisors inclination pre and post orthodontic decompensation in skeletal Class III malocclusion. Methods: The study was conducted on six individuals with skeletal Class III malocclusion, surgically treated, who had Cone-Beam Computed Tomographic scans obtained before and after orthodontic decompensation. On multiplanar reconstruction view, tomographic slices (axial, coronal and sagittal) were obtained on the long axis of each incisor. The sagittal slice was used for measurement taking, whereas the references used to assess tooth inclination were the long axis of maxillary teeth in relation to the palatal plane and the long axis of mandibular teeth in relation to the mandibular plane. Results: There was significant variation in the inclination of incisors before and after orthodontic decompensation. This change was of greater magnitude in the mandibular arch, evidencing that natural compensation is more effective in this arch, thereby requiring more intensive decompensation. Conclusion: When routinely performed, the protocols of decompensation treatment in surgical individuals often result in intensive movements, which should be reevaluated, since the extent of movement predisposes to reduction in bone attachment levels and root length. PMID:26560818

Intracellular Membrane and Synaptic Properties in Medial Preoptic Slices Containing the Sexually Dimorphic Nucleus of the Rat

DTIC Science & Technology

1992-01-01

these events appear to be LTS potentials, as originally described in other central regions (Jahnsen and Llings 1984). In some media preoptic neurons, LTS...Kelly, J.S. An intracellular study of grafted and in situ preoptic area neurones in brain slices from normal and hypogonadal mice. J Physiol. 423: 111... central nervous system function. Science 242: 1654-1664, 1988. Llings, R., and Yarom, Y. Electrophysiology of mammalian inferior olivary neurons in vitro

Rapid Parametric Mapping of the Longitudinal Relaxation Time T1 Using Two-Dimensional Variable Flip Angle Magnetic Resonance Imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla

PubMed Central

Dieringer, Matthias A.; Deimling, Michael; Santoro, Davide; Wuerfel, Jens; Madai, Vince I.; Sobesky, Jan; von Knobelsdorff-Brenkenhoff, Florian; Schulz-Menger, Jeanette; Niendorf, Thoralf

2014-01-01

Introduction Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1+) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time consuming. For this reason, this study examines the feasibility of rapid 2D T1 quantification using a variable flip angles (VFA) approach at magnetic field strengths of 1.5 Tesla, 3 Tesla, and 7 Tesla. These efforts include validation in phantom experiments and application for brain T1 mapping. Methods T1 quantification included simulations of the Bloch equations to correct for slice profile imperfections, and a correction for B1+. Fast gradient echo acquisitions were conducted using three adjusted flip angles for the proposed T1 quantification approach that was benchmarked against slice profile uncorrected 2D VFA and an inversion-recovery spin-echo based reference method. Brain T1 mapping was performed in six healthy subjects, one multiple sclerosis patient, and one stroke patient. Results Phantom experiments showed a mean T1 estimation error of (-63±1.5)% for slice profile uncorrected 2D VFA and (0.2±1.4)% for the proposed approach compared to the reference method. Scan time for single slice T1 mapping including B1+ mapping could be reduced to 5 seconds using an in-plane resolution of (2×2) mm2, which equals a scan time reduction of more than 99% compared to the reference method. Conclusion Our results demonstrate that rapid 2D T1 quantification using a variable flip angle approach is feasible at 1.5T/3T/7T. It represents a valuable alternative for rapid T1 mapping due to the gain in speed versus conventional approaches. This progress may serve to enhance the capabilities of parametric MR based lesion detection and brain tissue characterization. PMID:24621588

Rapid parametric mapping of the longitudinal relaxation time T1 using two-dimensional variable flip angle magnetic resonance imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla.

PubMed

Dieringer, Matthias A; Deimling, Michael; Santoro, Davide; Wuerfel, Jens; Madai, Vince I; Sobesky, Jan; von Knobelsdorff-Brenkenhoff, Florian; Schulz-Menger, Jeanette; Niendorf, Thoralf

2014-01-01

Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1+) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time consuming. For this reason, this study examines the feasibility of rapid 2D T1 quantification using a variable flip angles (VFA) approach at magnetic field strengths of 1.5 Tesla, 3 Tesla, and 7 Tesla. These efforts include validation in phantom experiments and application for brain T1 mapping. T1 quantification included simulations of the Bloch equations to correct for slice profile imperfections, and a correction for B1+. Fast gradient echo acquisitions were conducted using three adjusted flip angles for the proposed T1 quantification approach that was benchmarked against slice profile uncorrected 2D VFA and an inversion-recovery spin-echo based reference method. Brain T1 mapping was performed in six healthy subjects, one multiple sclerosis patient, and one stroke patient. Phantom experiments showed a mean T1 estimation error of (-63±1.5)% for slice profile uncorrected 2D VFA and (0.2±1.4)% for the proposed approach compared to the reference method. Scan time for single slice T1 mapping including B1+ mapping could be reduced to 5 seconds using an in-plane resolution of (2×2) mm2, which equals a scan time reduction of more than 99% compared to the reference method. Our results demonstrate that rapid 2D T1 quantification using a variable flip angle approach is feasible at 1.5T/3T/7T. It represents a valuable alternative for rapid T1 mapping due to the gain in speed versus conventional approaches. This progress may serve to enhance the capabilities of parametric MR based lesion detection and brain tissue characterization.

Bilirubin and its oxidation products damage brain white matter

PubMed Central

Lakovic, Katarina; Ai, Jinglu; D'Abbondanza, Josephine; Tariq, Asma; Sabri, Mohammed; Alarfaj, Abdullah K; Vasdev, Punarjot; Macdonald, Robert Loch

2014-01-01

Brain injury after intracerebral hemorrhage (ICH) occurs in cortex and white matter and may be mediated by blood breakdown products, including hemoglobin and heme. Effects of blood breakdown products, bilirubin and bilirubin oxidation products, have not been widely investigated in adult brain. Here, we first determined the effect of bilirubin and its oxidation products on the structure and function of white matter in vitro using brain slices. Subsequently, we determined whether these compounds have an effect on the structure and function of white matter in vivo. In all, 0.5 mmol/L bilirubin treatment significantly damaged both the function and the structure of myelinated axons but not the unmyelinated axons in brain slices. Toxicity of bilirubin in vitro was prevented by dimethyl sulfoxide. Bilirubin oxidation products (BOXes) may be responsible for the toxicity of bilirubin. In in vivo experiments, unmyelinated axons were found more susceptible to damage from bilirubin injection. These results suggest that unmyelinated axons may have a major role in white-matter damage in vivo. Since bilirubin and BOXes appear in a delayed manner after ICH, preventing their toxic effects may be worth investigating therapeutically. Dimethyl sulfoxide or its structurally related derivatives may have a potential therapeutic value at antagonizing axonal damage after hemorrhagic stroke. PMID:25160671

CALHM1 deficiency impairs cerebral neuron activity and memory flexibility in mice.

PubMed

Vingtdeux, Valérie; Chang, Eric H; Frattini, Stephen A; Zhao, Haitian; Chandakkar, Pallavi; Adrien, Leslie; Strohl, Joshua J; Gibson, Elizabeth L; Ohmoto, Makoto; Matsumoto, Ichiro; Huerta, Patricio T; Marambaud, Philippe

2016-04-12

CALHM1 is a cell surface calcium channel expressed in cerebral neurons. CALHM1 function in the brain remains unknown, but recent results showed that neuronal CALHM1 controls intracellular calcium signaling and cell excitability, two mechanisms required for synaptic function. Here, we describe the generation of Calhm1 knockout (Calhm1(-/-)) mice and investigate CALHM1 role in neuronal and cognitive functions. Structural analysis revealed that Calhm1(-/-) brains had normal regional and cellular architecture, and showed no evidence of neuronal or synaptic loss, indicating that CALHM1 deficiency does not affect brain development or brain integrity in adulthood. However, Calhm1(-/-) mice showed a severe impairment in memory flexibility, assessed in the Morris water maze, and a significant disruption of long-term potentiation without alteration of long-term depression, measured in ex vivo hippocampal slices. Importantly, in primary neurons and hippocampal slices, CALHM1 activation facilitated the phosphorylation of NMDA and AMPA receptors by protein kinase A. Furthermore, neuronal CALHM1 activation potentiated the effect of glutamate on the expression of c-Fos and C/EBPβ, two immediate-early gene markers of neuronal activity. Thus, CALHM1 controls synaptic activity in cerebral neurons and is required for the flexible processing of memory in mice. These results shed light on CALHM1 physiology in the mammalian brain.

Maternal treatment of rats with the new pyridoindole antioxidant during pregnacy and lactation resulting in improved offspring hippocampal resistance to ischemia in vitro.

PubMed

Gáspárová, Zdenka; Snirc, Vladimír; Stolc, Svorad; Dubovický, Michal; Mach, Mojmír; Ujházy, Eduard

2010-01-01

Damage to the developing brain may be caused by maternal environment, nutritional deficiencies, failure of protective mechanisms, etc. Further, the developing brain may be damaged by intrauterine ischemia or by ischemia in newborns complicated by perinatal asphyxia. There is an effort to find agents with neuroprotective effect on the developing brain. The aim was to study the effect of the new pyridoindole antioxidant SMe1EC2 on the resistance of offspring hippocampus exposed to ischemia in vitro after treatment of mothers. The electrically evoked responses were determined by extracellular recording from offspring hippocampal slices. The effect of oral treatment of rats with SMe1EC2 over 18 consecutive days, from day 15 of gestation to day 10 post partum (PP) was analyzed in the model of ischemia in vitro measured on the hippocampus of 21-day-old pups, with focus on neuronal function recovery in reoxygenation. Increased recovery of neuronal response was found at the end of 20-min reoxygenation in offspring hippocampal slices exposed to 10-min hypoxia/hypoglycemia from rats whose mothers were treated with the dose of 50 and 250 mg/kg of SMe1EC2, compared to control offspring slices (mothers received vehicle over the same time). The increased offspring hippocampus resistance to hypoxia/hypoglycemia due to 18-day maternal treatment with SMe1EC2 might have been obtained via the transplacental way as well as in the neonatal period via breast milk, skin and saliva. The manifested neuroprotective effect of SMe1EC2 on the developing brain might find exploitation during risk pregnancy and delivery.

Controlled single bubble cavitation collapse results in jet-induced injury in brain tissue.

PubMed

Canchi, Saranya; Kelly, Karen; Hong, Yu; King, Michael A; Subhash, Ghatu; Sarntinoranont, Malisa

2017-10-01

Multiscale damage due to cavitation is considered as a potential mechanism of traumatic brain injury (TBI) associated with explosion. In this study, we employed a TBI relevant hippocampal ex vivo slice model to induce bubble cavitation. Placement of single reproducible seed bubbles allowed control of size, number, and tissue location to visualize and measure deformation parameters. Maximum strain value was measured at 45 µs after bubble collapse, presented with a distinct contour and coincided temporally and spatially with the liquid jet. Composite injury maps combined this maximum strain value with maximum measured bubble size and location along with histological injury patterns. This facilitated the correlation of bubble location and subsequent jet direction to the corresponding regions of high strain which overlapped with regions of observed injury. A dynamic threshold strain range for tearing of cerebral cortex was estimated to be between 0.5 and 0.6. For a seed bubble placed underneath the hippocampus, cavitation induced damage was observed in hippocampus (local), proximal cerebral cortex (marginal) and the midbrain/forebrain (remote) upon histological evaluation. Within this test model, zone of cavitation injury was greater than the maximum radius of the bubble. Separation of apposed structures, tissue tearing, and disruption of cellular layers defined early injury patterns that were not detected in the blast-exposed half of the brain slice. Ultrastructural pathology of the neurons exposed to cavitation was characterized by disintegration of plasma membrane along with loss of cellular content. The developed test system provided a controlled experimental platform to study cavitation induced high strain deformations on brain tissue slice. The goal of the future studies will be to lower underpressure magnitude and cavitation bubble size for more sensitive evaluation of injury. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neural responses of rat cortical layers due to infrared neural modulation and photoablation of thalamocortical brain slices

NASA Astrophysics Data System (ADS)

Jenkins, J. Logan; Kao, Chris C.; Cayce, Jonathan M.; Mahadevan-Jansen, Anita; Jansen, E. Duco

2017-02-01

Infrared neural modulation (INM) is a label-free method for eliciting neural activity with high spatial selectivity in mammalian models. While there has been an emphasis on INM research towards applications in the peripheral nervous system and the central nervous system (CNS), the biophysical mechanisms by which INM occurs remains largely unresolved. In the rat CNS, INM has been shown to elicit and inhibit neural activity, evoke calcium signals that are dependent on glutamate transients and astrocytes, and modulate inhibitory GABA currents. So far, in vivo experiments have been restricted to layers I and II of the rat cortex which consists mainly of astrocytes, inhibitory neurons, and dendrites from deeper excitatory neurons owing to strong absorption of light in these layers. Deeper cortical layers (III-VI) have vastly different cell type composition, consisting predominantly of excitatory neurons which can be targeted for therapies such as deep brain stimulation. The neural responses to infrared light of deeper cortical cells have not been well defined. Acute thalamocortical brain slices will allow us to analyze the effects of INS on various components of the cortex, including different cortical layers and cell populations. In this study, we present the use of photoablation with an erbium:YAG laser to reduce the thickness of the dead cell zone near the cutting surface of brain slices. This technique will allow for more optical energy to reach living cells, which should contribute the successful transduction of pulsed infrared light to neural activity. In the future, INM-induced neural responses will lead to a finer characterization of the parameter space for the neuromodulation of different cortical cell types and may contribute to understanding the cell populations that are important for allowing optical stimulation of neurons in the CNS.

CT triage for lung malignancy: coronal multiplanar reformation versus images in three orthogonal planes.

PubMed

Kusk, Martin Weber; Karstoft, Jens; Mussmann, Bo Redder

2015-11-01

Generation of multiplanar reformation (MPR) images has become automatic on most modern computed tomography (CT) scanners, potentially increasing the workload of the reporting radiologists. It is not always clear if this increases diagnostic performance in all clinical tasks. To assess detection performance using only coronal multiplanar reformations (MPR) when triaging patients for lung malignancies with CT compared to images in three orthogonal planes, and to evaluate performance comparison of novice and experienced readers. Retrospective study of 63 patients with suspicion of lung cancer, scanned on 64-slice multidetector computed tomography (MDCT) with images reconstructed in three planes. Coronal images were presented to four readers, two novice and two experienced. Readers decided whether the patients were suspicious for malignant disease, and indicated their confidence on a five-point scale. Sensitivity and specificity on per-patient basis was calculated with regards to a reference standard of histological diagnosis, and compared with the original report using McNemar's test. Receiver operating characteristic (ROC) curves were plotted to compare the performance of the four readers, using the area under the curve (AUC) as figure of merit. No statistically significant difference of sensitivity and specificity was found for any of the readers when compared to the original reports. ROC analysis yielded AUCs in the range of 0.92-0.93 for all readers with no significant difference. Inter-rater agreement was substantial (kappa = 0.72). Sensitivity and specificity were comparable to diagnosis using images in three planes. No significant difference was found between experienced and novice readers. © The Foundation Acta Radiologica 2014.

Time-lapse imaging of neuroblast migration in acute slices of the adult mouse forebrain.

PubMed

Khlghatyan, Jivan; Saghatelyan, Armen

2012-09-12

There is a substantial body of evidence indicating that new functional neurons are constitutively generated from an endogenous pool of neural stem cells in restricted areas of the adult mammalian brain. Newborn neuroblasts from the subventricular zone (SVZ) migrate along the rostral migratory stream (RMS) to their final destination in the olfactory bulb (OB). In the RMS, neuroblasts migrate tangentially in chains ensheathed by astrocytic processes using blood vessels as a structural support and a source of molecular factors required for migration. In the OB, neuroblasts detach from the chains and migrate radially into the different bulbar layers where they differentiate into interneurons and integrate into the existing network. In this manuscript we describe the procedure for monitoring cell migration in acute slices of the rodent brain. The use of acute slices allows the assessment of cell migration in the microenvironment that closely resembling to in vivo conditions and in brain regions that are difficult to access for in vivo imaging. In addition, it avoids long culturing condition as in the case of organotypic and cell cultures that may eventually alter the migration properties of the cells. Neuronal precursors in acute slices can be visualized using DIC optics or fluorescent proteins. Viral labeling of neuronal precursors in the SVZ, grafting neuroblasts from reporter mice into the SVZ of wild-type mice, and using transgenic mice that express fluorescent protein in neuroblasts are all suitable methods for visualizing neuroblasts and following their migration. The later method, however, does not allow individual cells to be tracked for long periods of time because of the high density of labeled cells. We used a wide-field fluorescent upright microscope equipped with a CCD camera to achieve a relatively rapid acquisition interval (one image every 15 or 30 sec) to reliably identify the stationary and migratory phases. A precise identification of the duration of the stationary and migratory phases is crucial for the unambiguous interpretation of results. We also performed multiple z-step acquisitions to monitor neuroblasts migration in 3D. Wide-field fluorescent imaging has been used extensively to visualize neuronal migration. Here, we describe detailed protocol for labeling neuroblasts, performing real-time video-imaging of neuroblast migration in acute slices of the adult mouse forebrain, and analyzing cell migration. While the described protocol exemplified the migration of neuroblasts in the adult RMS, it can also be used to follow cell migration in embryonic and early postnatal brains.

Creation and Validation of a Simulator for Neonatal Brain Ultrasonography: A Pilot Study.

PubMed

Tsai, Andy; Barnewolt, Carol E; Prahbu, Sanjay P; Yonekura, Reimi; Hosmer, Andrew; Schulz, Noah E; Weinstock, Peter H

2017-01-01

Historically, skills training in performing brain ultrasonography has been limited to hours of scanning infants for lack of adequate synthetic models or alternatives. The aim of this study was to create a simulator and determine its utility as an educational tool in teaching the skills that can be used in performing brain ultrasonography on infants. A brain ultrasonography simulator was created using a combination of multi-modality imaging, three-dimensional printing, material and acoustic engineering, and sculpting and molding. Radiology residents participated prior to their pediatric rotation. The study included (1) an initial questionnaire and resident creation of three coronal images using the simulator; (2) brain ultrasonography lecture; (3) hands-on simulator practice; and (4) a follow-up questionnaire and re-creation of the same three coronal images on the simulator. A blinded radiologist scored the quality of the pre- and post-training images using metrics including symmetry of the images and inclusion of predetermined landmarks. Wilcoxon rank-sum test was used to compare pre- and post-training questionnaire rankings and image quality scores. Ten residents participated in the study. Analysis of pre- and post-training rankings showed improvements in technical knowledge and confidence, and reduction in anxiety in performing brain ultrasonography. Objective measures of image quality likewise improved. Mean reported value score for simulator training was high across participants who reported perceived improvements in scanning skills and enjoyment from simulator use, with interest in additional practice on the simulator and recommendations for its use. This pilot study supports the use of a simulator in teaching radiology residents the skills that can be used to perform brain ultrasonography. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

Conditional N-WASP knockout in mouse brain implicates actin cytoskeleton regulation in hydrocephalus pathology.

PubMed

Jain, Neeraj; Lim, Lee Wei; Tan, Wei Ting; George, Bhawana; Makeyev, Eugene; Thanabalu, Thirumaran

2014-04-01

Cerebrospinal fluid (CSF) is produced by the choroid plexus and moved by multi-ciliated ependymal cells through the ventricular system of the vertebrate brain. Defects in the ependymal layer functionality are a common cause of hydrocephalus. N-WASP (Neural-Wiskott Aldrich Syndrome Protein) is a brain-enriched regulator of actin cytoskeleton and N-WASP knockout caused embryonic lethality in mice with neural tube and cardiac abnormalities. To shed light on the role of N-WASP in mouse brain development, we generated N-WASP conditional knockout mouse model N-WASP(fl/fl); Nestin-Cre (NKO-Nes). NKO-Nes mice were born with Mendelian ratios but exhibited reduced growth characteristics compared to their littermates containing functional N-WASP alleles. Importantly, all NKO-Nes mice developed cranial deformities due to excessive CSF accumulation and did not survive past weaning. Coronal brain sections of these animals revealed dilated lateral ventricles, defects in ciliogenesis, loss of ependymal layer integrity, reduced thickness of cerebral cortex and aqueductal stenosis. Immunostaining for N-cadherin suggests that ependymal integrity in NKO-Nes mice is lost as compared to normal morphology in the wild-type controls. Moreover, scanning electron microscopy and immunofluorescence analyses of coronal brain sections with anti-acetylated tubulin antibodies revealed the absence of cilia in ventricular walls of NKO-Nes mice indicative of ciliogenesis defects. N-WASP deficiency does not lead to altered expression of N-WASP regulatory proteins, Fyn and Cdc42, which have been previously implicated in hydrocephalus pathology. Taken together, our results suggest that N-WASP plays a critical role in normal brain development and implicate actin cytoskeleton regulation as a vulnerable axis frequently deregulated in hydrocephalus. Copyright © 2014 Elsevier Inc. All rights reserved.

Serotonergic modulation of hippocampal pyramidal cells in euthermic, cold-acclimated, and hibernating hamsters

NASA Technical Reports Server (NTRS)

Horrigan, D. J.; Horwitz, B. A.; Horowitz, J. M.

1997-01-01

Serotonergic fibers project to the hippocampus, a brain area previously shown to have distinctive changes in electroencephalograph (EEG) activity during entrance into and arousal from hibernation. The EEG activity is generated by pyramidal cells in both hibernating and nonhibernating species. Using the brain slice preparation, we characterized serotonergic responses of these CA1 pyramidal cells in euthermic, cold-acclimated, and hibernating Syrian hamsters. Stimulation of Shaffer-collateral/commissural fibers evoked fast synaptic excitation of CA1 pyramidal cells, a response monitored by recording population spikes (the synchronous generation of action potentials). Neuromodulation by serotonin (5-HT) decreased population spike amplitude by 54% in cold-acclimated animals, 80% in hibernating hamsters, and 63% in euthermic animals. The depression was significantly greater in slices from hibernators than from cold-acclimated animals. In slices from euthermic animals, changes in extracellular K+ concentration between 2.5 and 5.0 mM did not significantly alter serotonergic responses. The 5-HT1A agonist 8-hydroxy-2(di-n-propylamino)tetralin mimicked serotonergic inhibition in euthermic hamsters. Results show that 5-HT is a robust neuromodulator not only in euthermic animals but also in cold-acclimated and hibernating hamsters.

Tyramine-induced noradrenaline release from rat brain slices: prevention by (-)-deprenyl.

PubMed Central

Glover, V.; Pycock, C. J.; Sandler, M.

1983-01-01

Clorgyline (1 and 10 microM) and (+)-deprenyl (10 microM) both significantly potentiated the tyramine (100 microM)-induced release of [3H]-noradrenaline from rat cerebral cortex slices. (-)-Deprenyl (50 microM) significantly reduced it, while lower concentrations had no effect on noradrenaline release. However, in combination, 1 microM (-)-deprenyl blocked the release-facilitating action of 1 microM clorgyline, and 10 microM (-)-deprenyl that of 10 microM (+)-deprenyl. Low concentrations of (+)- and (-)-deprenyl (1 and 10 microM), both selectively inhibited phenylethylamine oxidation by monoamine oxidase B. Higher concentrations of (-)-deprenyl (20 and 50 microM) also inhibited 5-hydroxytryptamine oxidation by monoamine oxidase A. Clorgyline (1 and 10 microM) inhibited both enzymes. Thus, the effects of these drugs on noradrenaline-release cannot be explained solely in terms of irreversible inhibition of monoamine oxidase A and B, and other possible mechanisms are discussed. If the brain-slice model faithfully mirrors the sequence of events manifesting peripherally as the tyramine hypertensive response ('cheese effect'), then it is possible that low doses of (-)-deprenyl, administered with antidepressant monoamine oxidase inhibitors, can prevent this adverse reaction. PMID:6418254

Analysis and 3D reconstruction of heterogeneity in malignant brain tumors: an interdisciplinary case study using a novel computational visualization approach.

PubMed

Mojsilovic, Aleksandra; Rogowitz, Bernice; Gomes, Jose; Deisboeck, Thomas S

2002-06-01

To explore how a multidisciplinary approach, combining modern visualization and image processing techniques with innovative experimental studies, can augment the understanding of tumor development. We analyzed histologic sections of a microscopic brain tumor and reconstructed these slices into a 3D representation. We processed these slices to: (1) identify tumor boundaries, (2) isolate proliferating tumor cells, and (3) segment the tumor into regions based on the density of proliferating cells. We then reconstructed the 3D shape of the tumor using a constrained deformable surface approach. This novel method allows the analyst to (1) see specific properties of histologic slices in the 3D environment with animation, (2) switch 2D "views" dynamically, and (3) see relationships between the 3D structure and structure on a plane. Using this method to analyze a specific "case," we were also able to shed light on the limitations of a widely held assumption about the shape of expanding microscopic solid tumors as well as find more indications that such tumors behave as adaptive biosystems. Implications of these case study results, as well as future applications of the method for tumor biology research, are discussed.

Chronic morphine treatment reduces recovery from opioid desensitization.

PubMed

Dang, Vu C; Williams, John T

2004-09-01

Tolerance and dependence result from long-term exposure to opioids, and there is growing evidence linking acute receptor desensitization to these more long-term processes. Receptor desensitization encompasses a series of events leading to the loss of receptor function and internalization. This study examines the onset and recovery from desensitization in locus ceruleus neurons recorded in brain slices taken from animals that have been chronically treated with morphine. After chronic morphine treatment, desensitization was altered as follows. First, the rate of desensitization was increased. Second, recovery from desensitization was always incomplete, even after a brief (1-2 min) exposure to agonist. This contrasts with experiments in controls in which recovery from desensitization, after a brief exposure to agonist, was complete within 25 min. Finally, morphine-6-beta-D-glucuronide, a metabolite of morphine that was ineffective at causing desensitization in controls, induced significant desensitization in slices from morphine-treated animals. When brain slices from controls were treated with inhibitors of PKC or monensin, agents known to compromise G-protein-coupled receptor resensitization, desensitization was increased, and recovery was significantly reduced. These results indicate that receptor resensitization maintains signaling during periods of intense and sustained stimulation. After chronic morphine treatment, desensitization is potentiated, and receptor resensitization is compromised.

Stimulation by atropine of acetylcholine release and synthesis in cortical slices from rat brain

PubMed Central

Molenaar, P. C.; Polak, R. L.

1970-01-01

1. Cortical slices from rat brain were incubated in media containing the irreversible cholinesterase inhibitor soman and a high KCl concentration, and the release and synthesis of acetylcholine (ACh) were determined. 2. Atropine enhanced the release and synthesis of ACh. 3. Tetrodotoxin, a substance which blocks nervous conduction, did not influence the release and synthesis of ACh, in the absence or in the presence of atropine. Therefore the nerve endings are probably the site at which atropine acts when stimulating the release and synthesis of ACh. 4. Pretreatment of the slices with botulinum type A toxin partially blocked the release and synthesis of ACh and reduced the extra amounts of ACh released and synthesized under the influence of atropine. 5. Lowering the calcium or raising the magnesium concentration in the incubation medium reduced the release and synthesis of ACh and their enhancement by atropine. 6. Physostigmine decreased the total extractable ACh content of the slices during incubation in a 25 mM KCl containing medium. This decrease was nearly prevented when the release and synthesis of ACh were inhibited by omission of the calcium ions from the medium, but was enhanced by atropine. 7. The observations made with pretreatment by botulinum type A toxin, with changes in the calcium and magnesium concentration as well as with physostigmine, all support the theory that it is primarily the release of ACh which is enhanced by atropine and that its stimulating action on the synthesis results from the increased release. PMID:5497792

Solar Tutorial and Annotation Resource (STAR)

NASA Astrophysics Data System (ADS)

Showalter, C.; Rex, R.; Hurlburt, N. E.; Zita, E. J.

2009-12-01

We have written a software suite designed to facilitate solar data analysis by scientists, students, and the public, anticipating enormous datasets from future instruments. Our “STAR" suite includes an interactive learning section explaining 15 classes of solar events. Users learn software tools that exploit humans’ superior ability (over computers) to identify many events. Annotation tools include time slice generation to quantify loop oscillations, the interpolation of event shapes using natural cubic splines (for loops, sigmoids, and filaments) and closed cubic splines (for coronal holes). Learning these tools in an environment where examples are provided prepares new users to comfortably utilize annotation software with new data. Upon completion of our tutorial, users are presented with media of various solar events and asked to identify and annotate the images, to test their mastery of the system. Goals of the project include public input into the data analysis of very large datasets from future solar satellites, and increased public interest and knowledge about the Sun. In 2010, the Solar Dynamics Observatory (SDO) will be launched into orbit. SDO’s advancements in solar telescope technology will generate a terabyte per day of high-quality data, requiring innovation in data management. While major projects develop automated feature recognition software, so that computers can complete much of the initial event tagging and analysis, still, that software cannot annotate features such as sigmoids, coronal magnetic loops, coronal dimming, etc., due to large amounts of data concentrated in relatively small areas. Previously, solar physicists manually annotated these features, but with the imminent influx of data it is unrealistic to expect specialized researchers to examine every image that computers cannot fully process. A new approach is needed to efficiently process these data. Providing analysis tools and data access to students and the public have proven efficient in similar astrophysical projects (e.g. the “Galaxy Zoo.”) For “crowdsourcing” to be effective for solar research, the public needs knowledge and skills to recognize and annotate key events on the Sun. Our tutorial can provide this training, with over 200 images and 18 movies showing examples of active regions, coronal dimmings, coronal holes, coronal jets, coronal waves, emerging flux, sigmoids, coronal magnetic loops, filaments, filament eruption, flares, loop oscillation, plage, surges, and sunspots. Annotation tools are provided for many of these events. Many features of the tutorial, such as mouse-over definitions and interactive annotation examples, are designed to assist people without previous experience in solar physics. After completing the tutorial, the user is presented with an interactive quiz: a series of movies and images to identify and annotate. The tutorial teaches the user, with feedback on correct and incorrect answers, until the user develops appropriate confidence and skill. This prepares users to annotate new data, based on their experience with event recognition and annotation tools. Trained users can contribute significantly to our data analysis tasks, even as our training tool contributes to public science literacy and interest in solar physics.

Evaluation of COPD's diaphragm motion extracted from 4D-MRI

NASA Astrophysics Data System (ADS)

Swastika, Windra; Masuda, Yoshitada; Kawata, Naoko; Matsumoto, Koji; Suzuki, Toshio; Iesato, Ken; Tada, Yuji; Sugiura, Toshihiko; Tanabe, Nobuhiro; Tatsumi, Koichiro; Ohnishi, Takashi; Haneishi, Hideaki

2015-03-01

We have developed a method called intersection profile method to construct a 4D-MRI (3D+time) from time-series of 2D-MRI. The basic idea is to find the best matching of the intersection profile from the time series of 2D-MRI in sagittal plane (navigator slice) and time series of 2D-MRI in coronal plane (data slice). In this study, we use 4D-MRI to semiautomatically extract the right diaphragm motion of 16 subjects (8 healthy subjects and 8 COPD patients). The diaphragm motion is then evaluated quantitatively by calculating the displacement of each subjects and normalized it. We also generate phase-length map to view and locate paradoxical motion of the COPD patients. The quantitative results of the normalized displacement shows that COPD patients tend to have smaller displacement compared to healthy subjects. The average normalized displacement of total 8 COPD patients is 9.4mm and the average of normalized displacement of 8 healthy volunteers is 15.3mm. The generated phase-length maps show that not all of the COPD patients have paradoxical motion, however if it has paradoxical motion, the phase-length map is able to locate where does it occur.

NTP and PCr responses to hypoxia by hypothermic and normothermic respiring, superfused, neonatal rat cerebrocortical slices: an NMR spectroscopy study at 14.1 Tesla.

PubMed

Litt, L; Hirai, K; Basus, V J; James, T L

2003-01-01

Although mechanisms of hypothermic neuroprotection during oxygen deprivation have long been investigated, further characterizations of various molecular mechanisms are appropriate. Anticipating future studies of hypothermia and hypoxia/ischemia, we investigated the extent to which our ex vivo, NMR-based, superfused brain slice model might be helpful. (Slices are approximately 350 microm thick, with 18 slices per 8 mm NMR tube.) 31P NMR spectroscopic measurements were made of hypothermia-induced changes in high energy phosphates, while simultaneously monitoring and controlling tissue temperature, using 1H NMR, the high spectroscopic resolution available at 14.1 Tesla (600 MHz for protons), and a recently published protocol. NTP and PCr concentrations in healthy, well-oxygenated slices decreased to (55 +/- 15)% and (66 +/- 30)% of their respective values at 28.0 degrees C when warmed to 38.0 degrees C, in approximate agreement with earlier in vivo studies by others. During 30 min hypoxia NTP and PCr decreased to non-observable values, regardless of temperature. After reoxygenation, NTP and PCr recoveries as percentages of respective prehypoxia values were (63% +/- 16%; 70%) +/- 5%) for hypothermic slices (28.0 degrees C), and (46% +/- 13%; 41% +/- hypothermic neuroprotection during oxygen deprivation in this model, which appears suitable for use in further studies.

Acute action of rotenone on excitability of catecholaminergic neurons in rostral ventrolateral medulla.

PubMed

Zhang, Zhaoqiang; Shi, Limin; Du, Xixun; Jiao, Qian; Jiang, Hong

2017-09-01

The degeneration of the rostral ventrolateral medulla (RVLM) catecholaminergic neurons was responsible for some cardiovascular symptoms in Parkinson's disease (PD). Our previous study had observed the impairment of these neurons in the early stage of PD in the rotenone-induced PD rat model, but the related mechanisms remain unclear. Rotenone is a mitochondrial inhibitor, influencing the neuronal electrophysiological activity through activation of K-ATP channels that potentially participate in cell death processes. In the present study, effects of rotenone on electrophysiological properties of RVLM catecholaminergic neurons and its underlying mechanisms were investigated. In coronal slices of brain containing the RVLM through patch clamp technique, rotenone (0.5μM) induced gradual postsynaptic inhibition on the spontaneous firing and cell membrane hyperpolarization with outward currents of catecholaminergic neurons. The electrophysiological changes were blocked by glibenclamide (30μM), a blocker of K-ATP channels, and were nearly unchanged by diazoxide (100μM), an opener of K-ATP channels. Our results also showed that effects of rotenone on catecholaminergic neurons including reactive oxygen species (ROS) generation were prevented by pretreatment of coenzyme Q10 (CoQ10, 100μM), a scavenger of ROS. These suggest that rotenone-induced electrophysiological changes of RVLM catecholaminergic neurons are caused by the opening of K-ATP channels, which are partly related to ROS generation. The changes of K-ATP channels might account for the vulnerability of RVLM catecholaminergic neurons. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of head size/shape, miscentering, and bowtie filter on peak patient tissue doses from modern brain perfusion 256-slice CT: How can we minimize the risk for deterministic effects?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perisinakis, Kostas; Seimenis, Ioannis; Tzedakis, Antonis

Purpose: To determine patient-specific absorbed peak doses to skin, eye lens, brain parenchyma, and cranial red bone marrow (RBM) of adult individuals subjected to low-dose brain perfusion CT studies on a 256-slice CT scanner, and investigate the effect of patient head size/shape, head position during the examination and bowtie filter used on peak tissue doses. Methods: The peak doses to eye lens, skin, brain, and RBM were measured in 106 individual-specific adult head phantoms subjected to the standard low-dose brain perfusion CT on a 256-slice CT scanner using a novel Monte Carlo simulation software dedicated for patient CT dosimetry. Peakmore » tissue doses were compared to corresponding thresholds for induction of cataract, erythema, cerebrovascular disease, and depression of hematopoiesis, respectively. The effects of patient head size/shape, head position during acquisition and bowtie filter used on resulting peak patient tissue doses were investigated. The effect of eye-lens position in the scanned head region was also investigated. The effect of miscentering and use of narrow bowtie filter on image quality was assessed. Results: The mean peak doses to eye lens, skin, brain, and RBM were found to be 124, 120, 95, and 163 mGy, respectively. The effect of patient head size and shape on peak tissue doses was found to be minimal since maximum differences were less than 7%. Patient head miscentering and bowtie filter selection were found to have a considerable effect on peak tissue doses. The peak eye-lens dose saving achieved by elevating head by 4 cm with respect to isocenter and using a narrow wedge filter was found to approach 50%. When the eye lies outside of the primarily irradiated head region, the dose to eye lens was found to drop to less than 20% of the corresponding dose measured when the eye lens was located in the middle of the x-ray beam. Positioning head phantom off-isocenter by 4 cm and employing a narrow wedge filter results in a moderate reduction of signal-to-noise ratio mainly to the peripheral region of the phantom. Conclusions: Despite typical peak doses to skin, eye lens, brain, and RBM from the standard low-dose brain perfusion 256-slice CT protocol are well below the corresponding thresholds for the induction of erythema, cataract, cerebrovascular disease, and depression of hematopoiesis, respectively, every effort should be made toward optimization of the procedure and minimization of dose received by these tissues. The current study provides evidence that the use of the narrower bowtie filter available may considerably reduce peak absorbed dose to all above radiosensitive tissues with minimal deterioration in image quality. Considerable reduction in peak eye-lens dose may also be achieved by positioning patient head center a few centimeters above isocenter during the exposure.« less

SU-E-J-25: End-To-End (E2E) Testing On TomoHDA System Using a Real Pig Head for Intracranial Radiosurgery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Corradini, N; Leick, M; Bonetti, M

Purpose: To determine the MVCT imaging uncertainty on the TomoHDA system for intracranial radiosurgery treatments. To determine the end-to-end (E2E) overall accuracy of the TomoHDA system for intracranial radiosurgery. Methods: A pig head was obtained from the butcher, cut coronally through the brain, and preserved in formaldehyde. The base of the head was fixed to a positioning plate allowing precise movement, i.e. translation and rotation, in all 6 axes. A repeatability test was performed on the pig head to determine uncertainty in the image bone registration algorithm. Furthermore, the test studied images with MVCT slice thicknesses of 1 and 3more » mm in unison with differing scan lengths. A sensitivity test was performed to determine the registration algorithm’s ability to find the absolute position of known translations/rotations of the pig head. The algorithm’s ability to determine absolute position was compared against that of manual operators, i.e. a radiation therapist and radiation oncologist. Finally, E2E tests for intracranial radiosurgery were performed by measuring the delivered dose distributions within the pig head using Gafchromic films. Results: The repeatability test uncertainty was lowest for the MVCTs of 1-mm slice thickness, which measured less than 0.10 mm and 0.12 deg for all axes. For the sensitivity tests, the bone registration algorithm performed better than human eyes and a maximum difference of 0.3 mm and 0.4 deg was observed for the axes. E2E test results in absolute position difference measured 0.03 ± 0.21 mm in x-axis and 0.28 ± 0.18 mm in y-axis. A maximum difference of 0.32 and 0.66 mm was observed in x and y, respectively. The average peak dose difference between measured and calculated dose was 2.7 cGy or 0.4%. Conclusion: Our tests using a pig head phantom estimate the TomoHDA system to have a submillimeter overall accuracy for intracranial radiosurgery.« less

Strain-Dependent Effects of Acute Alcohol on Synaptic Vesicle Recycling and Post-Tetanic Potentiation in Medial Glutamate Inputs to the Mouse Basolateral Amygdala.

PubMed

Gioia, Dominic A; McCool, Brian

2017-04-01

Inbred mouse strains are differentially sensitive to the acute effects of ethanol (EtOH) and are useful tools for examining how unique genomes differentially affect alcohol-related behaviors and physiology. DBA/2J mice have been shown to be sensitive to the acute anxiolytic effects of alcohol as well as the anxiogenic effects of withdrawal from chronic alcohol exposure, while B6 mice are resistant to both. Considering that the basolateral amygdala (BLA) is an important brain region for the acute and chronic effects of EtOH on fear and anxiety related behaviors, we hypothesized that there would be strain-dependent differences in the acute effects of EtOH in BLA slices. We utilized patch clamp electrophysiology in BLA coronal slices from 4 inbred mouse strains (A/J, BALBcJ, C57BL/6J, and DBA/2J) to examine how genetic background influences acute EtOH effects on synaptic vesicle recycling and post-tetanic potentiation (PTP) in response to low (2 Hz)- and high (40 Hz)-frequency stimulation. We found that EtOH inhibited synaptic vesicle recycling in a strain- and stimulation frequency-dependent manner. Vesicle recycling in DBA/2J and BALBcJ cells was inhibited by acute EtOH during both low- and high-frequency stimulation, while recycling measured from A/J cells was sensitive only during high-frequency stimulation. Recycling at C57BL/6J synapses was insensitive to EtOH regardless of stimulation frequency. We additionally found that cells from DBA/2J and BALBcJ mice were sensitive to EtOH-mediated inhibition of PTP. Acute EtOH application inhibited vesicle recycling and PTP at glutamatergic synapses in both a strain- and frequency-dependent fashion. Several presynaptic proteins that contribute to synaptic vesicle priming in addition to PTP have been implicated in alcohol-related behaviors, including Munc13, Munc18, and RIM proteins, making them potential candidates for the molecular mechanism controlling these effects. Copyright © 2017 by the Research Society on Alcoholism.

Syringe-injectable mesh electronics integrate seamlessly with minimal chronic immune response in the brain

PubMed Central

Zhou, Tao; Hong, Guosong; Fu, Tian-Ming; Yang, Xiao; Schuhmann, Thomas G.; Viveros, Robert D.; Lieber, Charles M.

2017-01-01

Implantation of electrical probes into the brain has been central to both neuroscience research and biomedical applications, although conventional probes induce gliosis in surrounding tissue. We recently reported ultraflexible open mesh electronics implanted into rodent brains by syringe injection that exhibit promising chronic tissue response and recording stability. Here we report time-dependent histology studies of the mesh electronics/brain-tissue interface obtained from sections perpendicular and parallel to probe long axis, as well as studies of conventional flexible thin-film probes. Confocal fluorescence microscopy images of the perpendicular and parallel brain slices containing mesh electronics showed that the distribution of astrocytes, microglia, and neurons became uniform from 2–12 wk, whereas flexible thin-film probes yield a marked accumulation of astrocytes and microglia and decrease of neurons for the same period. Quantitative analyses of 4- and 12-wk data showed that the signals for neurons, axons, astrocytes, and microglia are nearly the same from the mesh electronics surface to the baseline far from the probes, in contrast to flexible polymer probes, which show decreases in neuron and increases in astrocyte and microglia signals. Notably, images of sagittal brain slices containing nearly the entire mesh electronics probe showed that the tissue interface was uniform and neurons and neurofilaments penetrated through the mesh by 3 mo postimplantation. The minimal immune response and seamless interface with brain tissue postimplantation achieved by ultraflexible open mesh electronics probes provide substantial advantages and could enable a wide range of opportunities for in vivo chronic recording and modulation of brain activity in the future. PMID:28533392

Syringe-injectable mesh electronics integrate seamlessly with minimal chronic immune response in the brain.

PubMed

Zhou, Tao; Hong, Guosong; Fu, Tian-Ming; Yang, Xiao; Schuhmann, Thomas G; Viveros, Robert D; Lieber, Charles M

2017-06-06

Implantation of electrical probes into the brain has been central to both neuroscience research and biomedical applications, although conventional probes induce gliosis in surrounding tissue. We recently reported ultraflexible open mesh electronics implanted into rodent brains by syringe injection that exhibit promising chronic tissue response and recording stability. Here we report time-dependent histology studies of the mesh electronics/brain-tissue interface obtained from sections perpendicular and parallel to probe long axis, as well as studies of conventional flexible thin-film probes. Confocal fluorescence microscopy images of the perpendicular and parallel brain slices containing mesh electronics showed that the distribution of astrocytes, microglia, and neurons became uniform from 2-12 wk, whereas flexible thin-film probes yield a marked accumulation of astrocytes and microglia and decrease of neurons for the same period. Quantitative analyses of 4- and 12-wk data showed that the signals for neurons, axons, astrocytes, and microglia are nearly the same from the mesh electronics surface to the baseline far from the probes, in contrast to flexible polymer probes, which show decreases in neuron and increases in astrocyte and microglia signals. Notably, images of sagittal brain slices containing nearly the entire mesh electronics probe showed that the tissue interface was uniform and neurons and neurofilaments penetrated through the mesh by 3 mo postimplantation. The minimal immune response and seamless interface with brain tissue postimplantation achieved by ultraflexible open mesh electronics probes provide substantial advantages and could enable a wide range of opportunities for in vivo chronic recording and modulation of brain activity in the future.

A versatile new technique to clear mouse and human brain

NASA Astrophysics Data System (ADS)

Costantini, Irene; Di Giovanna, Antonino Paolo; Allegra Mascaro, Anna Letizia; Silvestri, Ludovico; Müllenbroich, Marie Caroline; Sacconi, Leonardo; Pavone, Francesco S.

2015-07-01

Large volumes imaging with microscopic resolution is limited by light scattering. In the last few years based on refractive index matching, different clearing approaches have been developed. Organic solvents and water-based optical clearing agents have been used for optical clearing of entire mouse brain. Although these methods guarantee high transparency and preservation of the fluorescence, though present other non-negligible limitations. Tissue transformation by CLARITY allows high transparency, whole brain immunolabelling and structural and molecular preservation. This method however requires a highly expensive refractive index matching solution limiting practical applicability. In this work we investigate the effectiveness of a water-soluble clearing agent, the 2,2'-thiodiethanol (TDE) to clear mouse and human brain. TDE does not quench the fluorescence signal, is compatible with immunostaining and does not introduce any deformation at sub-cellular level. The not viscous nature of the TDE make it a suitable agent to perform brain slicing during serial two-photon (STP) tomography. In fact, by improving penetration depth it reduces tissue slicing, decreasing the acquisition time and cutting artefacts. TDE can also be used as a refractive index medium for CLARITY. The potential of this method has been explored by imaging a whole transgenic mouse brain with the light sheet microscope. Moreover we apply this technique also on blocks of dysplastic human brain tissue transformed with CLARITY and labeled with different antibody. This clearing approach significantly expands the application of single and two-photon imaging, providing a new useful method for quantitative morphological analysis of structure in mouse and human brain.

Effect of time period after boric acid injection on 10B absorption in different regions of adult male rat's brain.

PubMed

Khojasteh, Nasrin Baghban; Pazirandeh, Ali; Jameie, Behnam; Goodarzi, Samereh

2012-06-01

Distribution of (10)B in different regions of rat normal brain was studied. Two groups were chosen as control and trial. Trial group received 2 ml of neutral boron compound. 2, 4 and 6 h after the injection brain removed, coronal sections of forebrain, midbrain and hindbrain were sandwiched between two pieces of polycarbonate. Autoradiography plots of (10)B distribution showed significant differences in three regions with the highest (10)B concentration in the forebrain during 4 h after injection. Copyright © 2012 Elsevier Ltd. All rights reserved.

Linear-array based full-view high-resolution photoacoustic computed tomography of whole mouse brain functions in vivo

NASA Astrophysics Data System (ADS)

Li, Lei; Zhang, Pengfei; Wang, Lihong V.

2018-02-01

Photoacoustic computed tomography (PACT) is a non-invasive imaging technique offering high contrast, high resolution, and deep penetration in biological tissues. We report a photoacoustic computed tomography (PACT) system equipped with a high frequency linear array for anatomical and functional imaging of the mouse whole brain. The linear array was rotationally scanned in the coronal plane to achieve the full-view coverage. We investigated spontaneous neural activities in the deep brain by monitoring the hemodynamics and observed strong interhemispherical correlations between contralateral regions, both in the cortical layer and in the deep regions.

Photoacoustic imaging to detect rat brain activation after cocaine hydrochloride injection

NASA Astrophysics Data System (ADS)

Jo, Janggun; Yang, Xinmai

2011-03-01

Photoacoustic imaging (PAI) was employed to detect small animal brain activation after the administration of cocaine hydrochloride. Sprague Dawley rats were injected with different concentrations (2.5, 3.0, and 5.0 mg per kg body) of cocaine hydrochloride in saline solution through tail veins. The brain functional response to the injection was monitored by photoacoustic tomography (PAT) system with horizontal scanning of cerebral cortex of rat brain. Photoacoustic microscopy (PAM) was also used for coronal view images. The modified PAT system used multiple ultrasonic detectors to reduce the scanning time and maintain a good signal-to-noise ratio (SNR). The measured photoacoustic signal changes confirmed that cocaine hydrochloride injection excited high blood volume in brain. This result shows PAI can be used to monitor drug abuse-induced brain activation.

Metabolic Characterization of Acutely Isolated Hippocampal and Cerebral Cortical Slices Using [U-13C]Glucose and [1,2-13C]Acetate as Substrates.

PubMed

McNair, Laura F; Kornfelt, Rasmus; Walls, Anne B; Andersen, Jens V; Aldana, Blanca I; Nissen, Jakob D; Schousboe, Arne; Waagepetersen, Helle S

2017-03-01

Brain slice preparations from rats, mice and guinea pigs have served as important tools for studies of neurotransmission and metabolism. While hippocampal slices routinely have been used for electrophysiology studies, metabolic processes have mostly been studied in cerebral cortical slices. Few comparative characterization studies exist for acute hippocampal and cerebral cortical slices, hence, the aim of the current study was to characterize and compare glucose and acetate metabolism in these slice preparations in a newly established incubation design. Cerebral cortical and hippocampal slices prepared from 16 to 18-week-old mice were incubated for 15-90 min with unlabeled glucose in combination with [U- 13 C]glucose or [1,2- 13 C]acetate. Our newly developed incubation apparatus allows accurate control of temperature and is designed to avoid evaporation of the incubation medium. Subsequent to incubation, slices were extracted and extracts analyzed for 13 C-labeling (%) and total amino acid contents (µmol/mg protein) using gas chromatography-mass spectrometry and high performance liquid chromatography, respectively. Release of lactate from the slices was quantified by analysis of the incubation media. Based on the measured 13 C-labeling (%), total amino acid contents and relative activity of metabolic enzymes/pathways, we conclude that the slice preparations in the current incubation apparatus exhibited a high degree of metabolic integrity. Comparison of 13 C-labeling observed with [U- 13 C]glucose in slices from cerebral cortex and hippocampus revealed no significant regional differences regarding glycolytic or total TCA cycle activities. On the contrary, results from the incubations with [1,2- 13 C]acetate suggest a higher capacity of the astrocytic TCA cycle in hippocampus compared to cerebral cortex. Finally, we propose a new approach for assessing compartmentation of metabolite pools between astrocytes and neurons using 13 C-labeling (%) data obtained from mass spectrometry. Based on this approach we suggest that cellular metabolic compartmentation in hippocampus and cerebral cortex is very similar.

Neuroanatomy of the killer whale (Orcinus orca) from magnetic resonance images.

PubMed

Marino, Lori; Sherwood, Chet C; Delman, Bradley N; Tang, Cheuk Y; Naidich, Thomas P; Hof, Patrick R

2004-12-01

This article presents the first series of MRI-based anatomically labeled sectioned images of the brain of the killer whale (Orcinus orca). Magnetic resonance images of the brain of an adult killer whale were acquired in the coronal and axial planes. The gross morphology of the killer whale brain is comparable in some respects to that of other odontocete brains, including the unusual spatial arrangement of midbrain structures. There are also intriguing differences. Cerebral hemispheres appear extremely convoluted and, in contrast to smaller cetacean species, the killer whale brain possesses an exceptional degree of cortical elaboration in the insular cortex, temporal operculum, and the cortical limbic lobe. The functional and evolutionary implications of these features are discussed. (c) 2004 Wiley-Liss, Inc.

Using 31P NMR spectroscopy at 14.1 Tesla to investigate PARP-1 associated energy failure and metabolic rescue in cerebrocortical slices.

PubMed

Zeng, Jianying; Hirai, Kiyoshi; Yang, Guo-Yuan; Ying, Weihai; Swanson, Raymond A; Kelly, Mark; Mayer, Moriz; James, Thomas L; Litt, Lawrence

2004-08-01

PARP-1 activation by H(2)O(2) in an acute preparation of superfused, respiring, neonatal cerebrocortical slices was assessed from PAR-polymer formation detected with immunohistochemistry and Western blotting. (31)P NMR spectroscopy at 14.1 Tesla of perchloric acid slice extracts was used to assess energy failure in a 1-h H(2)O(2) exposure as well as in a subsequent 4-h recovery period where the superfusate had no H(2)O(2) and specifically chosen metabolic substrates. Although more data are needed to fully characterize different bioenergetic responses, a high NMR spectral resolution (PCr full-width at half-max approximately.01 ppm) and narrow widths for most metabolites (<.2 ppm) permitted accurate quantifications of spectrally resolved resonances for ADP, ATP, NAD(+)/NADH, and other high energy phosphates. It appears possible to use brain slices to quantitatively study PARP-related, NAD-associated energy failure, and rescue with TCA metabolites.

Exploring Mechanisms Underlying Impaired Brain Function in Gulf War Illness through Advanced Network Analysis

DTIC Science & Technology

2017-10-01

networks of the brain responsible for visual processing, mood regulation, motor coordination, sensory processing, and language command, but increased...4    For each subject, the rsFMRI voxel time-series were temporally shifted to account for differences in slice acquisition times...responsible for visual processing, mood regulation, motor coordination, sensory processing, and language command, but increased connectivity in

Muscarinic agonists and phorbol esters increase tyrosine phosphorylation of a 40-kilodalton protein in hippocampal slices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stratton, K.R.; Worley, P.F.; Huganir, R.L.

The authors have used the hippocampal slice preparation to investigate the regulation of protein tyrosine phosphorylation in brain. After pharmacological treatment of intact slices, proteins were separated by electrophoresis, and levels of protein tyrosine phosphorylation were assessed by immunoblotting with specific anti-phosphotyrosine antibodies. Phorbol esters, activators of the serine- and threonine-phosphorylating enzyme protein kinase C, selectively increase tyrosine phosphorylation of a soluble protein with an apparent molecular mass of approximately 40 kilodaltons. Muscarinic agonists such as carbachol and oxotremorine M that strongly activate the inositol phospholipid system also increase tyrosine phosphorylation of this protein. Neurotransmitter activation of the inositol phospholipidmore » system and protein kinase C appears to trigger a cascade leading to increased tyrosine phosphorylation.« less

High-resolution brain SPECT imaging by combination of parallel and tilted detector heads.

PubMed

Suzuki, Atsuro; Takeuchi, Wataru; Ishitsu, Takafumi; Morimoto, Yuichi; Kobashi, Keiji; Ueno, Yuichiro

2015-10-01

To improve the spatial resolution of brain single-photon emission computed tomography (SPECT), we propose a new brain SPECT system in which the detector heads are tilted towards the rotation axis so that they are closer to the brain. In addition, parallel detector heads are used to obtain the complete projection data set. We evaluated this parallel and tilted detector head system (PT-SPECT) in simulations. In the simulation study, the tilt angle of the detector heads relative to the axis was 45°. The distance from the collimator surface of the parallel detector heads to the axis was 130 mm. The distance from the collimator surface of the tilted detector heads to the origin on the axis was 110 mm. A CdTe semiconductor panel with a 1.4 mm detector pitch and a parallel-hole collimator were employed in both types of detector head. A line source phantom, cold-rod brain-shaped phantom, and cerebral blood flow phantom were evaluated. The projection data were generated by forward-projection of the phantom images using physics models, and Poisson noise at clinical levels was applied to the projection data. The ordered-subsets expectation maximization algorithm with physics models was used. We also evaluated conventional SPECT using four parallel detector heads for the sake of comparison. The evaluation of the line source phantom showed that the transaxial FWHM in the central slice for conventional SPECT ranged from 6.1 to 8.5 mm, while that for PT-SPECT ranged from 5.3 to 6.9 mm. The cold-rod brain-shaped phantom image showed that conventional SPECT could visualize up to 8-mm-diameter rods. By contrast, PT-SPECT could visualize up to 6-mm-diameter rods in upper slices of a cerebrum. The cerebral blood flow phantom image showed that the PT-SPECT system provided higher resolution at the thalamus and caudate nucleus as well as at the longitudinal fissure of the cerebrum compared with conventional SPECT. PT-SPECT provides improved image resolution at not only upper but also at central slices of the cerebrum.

Novel MRI methodology to detect human whole-brain connectivity changes after ingestion of fructose or glucose

NASA Astrophysics Data System (ADS)

Tsao, Sinchai; Wilkins, Bryce; Page, Kathleen A.; Singh, Manbir

2012-03-01

A novel MRI protocol has been developed to investigate the differential effects of glucose or fructose consumption on whole-brain functional brain connectivity. A previous study has reported a decrease in the fMRI blood oxygen level dependent (BOLD) signal of the hypothalamus following glucose ingestion, but due to technical limitations, was restricted to a single slice covering the hypothalamus, and thus unable to detect whole-brain connectivity. In another previous study, a protocol was devised to acquire whole-brain fMRI data following food intake, but only after restricting image acquisition to an MR sampling or repetition time (TR) of 20s, making the protocol unsuitable to detect functional connectivity above 0.025Hz. We have successfully implemented a continuous 36-min, 40 contiguous slices, whole-brain BOLD acquisition protocol on a 3T scanner with TR=4.5s to ensure detection of up to 0.1Hz frequencies for whole-brain functional connectivity analysis. Human data were acquired first with ingestion of water only, followed by a glucose or fructose drink within the scanner, without interrupting the scanning. Whole-brain connectivity was analyzed using standard correlation methodology in the 0.01-0.1 Hz range. The correlation coefficient differences between fructose and glucose ingestion among targeted regions were converted to t-scores using the water-only correlation coefficients as a null condition. Results show a dramatic increase in the hypothalamic connectivity to the hippocampus, amygdala, insula, caudate and the nucleus accumben for fructose over glucose. As these regions are known to be key components of the feeding and reward brain circuits, these results suggest a preference for fructose ingestion.

Effects of lateral fluid percussion injury on cholinergic markers in the newborn piglet brain.

PubMed

Donat, Cornelius K; Walter, Bernd; Kayser, Tanja; Deuther-Conrad, Winnie; Schliebs, Reinhard; Nieber, Karen; Bauer, Reinhard; Härtig, Wolfgang; Brust, Peter

2010-02-01

Traumatic brain injury is a leading cause of death and disability in children. Studies using adult animal models showed alterations of the central cholinergic neurotransmission as a result of trauma. However, there is a lack of knowledge about consequences of brain trauma on cholinergic function in the immature brain. It is hypothesized that trauma affects the relative acetylcholine esterase activity and causes a loss of cholinergic neurons in the immature brain. Severe fluid percussion trauma (FP-TBI, 3.8+/-0.3atm) was induced in 15 female newborn piglets, monitored for 6h and compared with 12 control animals. The hemispheres ipsilateral to FP-TBI obtained from seven piglets were used for acetylcholine esterase histochemistry on frozen sagittal slices, while regional cerebral blood flow and oxygen availability was determined in the remaining eight FP-TBI animals. Post-fixed slices were immunohistochemically labelled for choline acetyltransferase as well as for low-affinity neurotrophin receptor in order to characterize cholinergic neurons in the basal forebrain. Regional cerebral blood flow and brain oxygen availability were reduced during the first 2h after FP-TBI (P<0.05). In addition, acetylcholine esterase activity was significantly increased in the neocortex, basal forebrain, hypothalamus and medulla after trauma (P<0.05), whereas the number of choline acetyltransferase and low-affinity neurotrophin receptor positive cells in the basal forebrain were unaffected by the injury. Thus, traumatic brain injury evoked an increased relative activity of the acetylcholine esterase in the immature brain early after injury, without loss of cholinergic neurons in the basal forebrain. These changes may contribute to developmental impairments after immature traumatic brain injury. Copyright 2009 ISDN. Published by Elsevier Ltd. All rights reserved.

Serotonin release varies with brain tryptophan levels

NASA Technical Reports Server (NTRS)

Schaechter, Judith D.; Wurtman, Richard J.

1990-01-01

This study examines directly the effects on serotonin release of varying brain tryptophan levels within the physiologic range. It also addresses possible interactions between tryptophan availability and the frequency of membrane depolarization in controlling serotonin release. We demonstrate that reducing tryptophan levels in rat hypothalamic slices (by superfusing them with medium supplemented with 100 microM leucine) decreases tissue serotonin levels as well as both the spontaneous and the electrically-evoked serotonin release. Conversely, elevating tissue tryptophan levels (by superfusing slices with medium supplemented with 2 microM tryptophan) increases both the tissue serotonin levels and the serotonin release. Serotonin release was found to be affected independently by the tryptophan availability and the frequency of electrical field-stimulation (1-5 Hz), since increasing both variables produced nearly additive increases in release. These observations demonstrate for the first time that both precursor-dependent elevations and reductions in brain serotonin levels produce proportionate changes in serotonin release, and that the magnitude of the tryptophan effect is unrelated to neuronal firing frequency. The data support the hypothesis that serotonin release is proportionate to intracellular serotonin levels.

Tissue Tracking: Applications for Brain MRI Classification

DTIC Science & Technology

2007-01-01

General Hospital, Center for Morphometric Analysis.10,11 The IBSR data-sets are T1-weighted, 3D coronal brain scans after having been positionally...learned priors,” Image Processing, IEEE Transactions on 9(2), pp. 299–301, 2000. 5. P. Olver, G. Sapiro, and A. Tannenbaum, “Invariant Geometric Evolutions...MRI,” NeuroImage 22(3), pp. 1060–1075, 2004. 16. A. Zijdenbos, B. Dawant, R. Margolin, and A. Palmer, “ Morphometric analysis of white matter lesions in

[Neuroprotective activity of the proline-containing dipeptide noopept on the model of brain ischemia induced by the middle cerebral artery occlusion].

PubMed

Gavrilova, S A; Us, K S; Ostrovskaia, R U; Koshelev, V B

2006-01-01

The influence of noopept (N-phenylacetyl-L-prolylglycine ethyl ester, GVS-111) on the extent of ischemic cortical stroke was investigated in experiments on white mongrel male rats with ischemia induced by a combination of the middle cerebral artery occlusion with ipsilateral common carotid artery ligation. Animals were treated with noopept (0.5 mg/kg, i.p.) according to the following schedule: 15 min and 2, 24, and 48 h after the occlusion. Test rats were decapitated 72 h after occlusion, brains were extracted and frozen, and thin brain slices were stained with 2,3,5-triphenyltetrazolium chloride. The slices were scanned and processed using Auc 1 computer program, which estimates the percentage of damaged area relative to that of the whole ipsilateral hemisphere. The conditions of coagulation the distal segment of middle cerebral artery were selected, which caused necrosis localized in the fronto-parietal and dorso-lateral regions of the brain cortex without any damage of subcortical structures. The extent of the brain damage in control group (treated by saline) was 18.6%, while that in the group treated with noopept was 12.2%, thus demonstrating a decrease in the infarction area by 34.5% (p < 05). The data on noopept efficacy on the model of the extensive ischemic injury of brain cortex show that this drug has good prospects for use in the neuroprotective treatment of stroke.

Dystrophic Serotonergic Axons in Neurodegenerative Diseases

PubMed Central

Azmitia, Efrain C.; Nixon, Ralph

2012-01-01

Neurodegenerative diseases such as Parkinson's disease (PD), frontal lobe dementia (FLD) and Diffuse Lewy-Body dementia (DLBD) have diverse neuropathologic features. Here we report that serotonin fibers are dystrophic in the brains of individuals with these three diseases. In neuropathologically normal (control) brains (n=3), serotonin axons immunoreactive (IR) with antibodies against the serotonin transporter (5-HTT) protein were widely distributed in cortex (entorhinal and dorsolateral prefrontal), hippocampus and rostral brainstem. 5-HTT-IR fibers of passage appeared thick, smooth, and un-branched in medial forebrain bundle, medial lemniscus and cortex white matter. The terminal branches were fine, highly branched and varicose in substantia nigra, hippocampus and cortical gray matter. In the diseased brains, however, 5-HTT-IR fibers in the forebrain were reduced in number and were frequently bulbous, splayed, tightly clustered and enlarged. Morphometric analysis revealed significant differences in the size distribution of the 5-HTT-IR profiles in dorsolateral prefrontal area between neurodegenerative diseases and controls. Our observations provide direct morphologic evidence for degeneration of human serotonergic axons in the brains of patients with neurodegenerative diseases despite the limited size (n=3 slices for each region (3) from each brain (4), total slices was n=36) and lack of extensive clinical characterization of the analyzed cohort. This is the first report of dystrophic 5-HTT-IR axons in postmortem human tissue PMID:18502405

Unsupervised fuzzy segmentation of 3D magnetic resonance brain images

NASA Astrophysics Data System (ADS)

Velthuizen, Robert P.; Hall, Lawrence O.; Clarke, Laurence P.; Bensaid, Amine M.; Arrington, J. A.; Silbiger, Martin L.

1993-07-01

Unsupervised fuzzy methods are proposed for segmentation of 3D Magnetic Resonance images of the brain. Fuzzy c-means (FCM) has shown promising results for segmentation of single slices. FCM has been investigated for volume segmentations, both by combining results of single slices and by segmenting the full volume. Different strategies and initializations have been tried. In particular, two approaches have been used: (1) a method by which, iteratively, the furthest sample is split off to form a new cluster center, and (2) the traditional FCM in which the membership grade matrix is initialized in some way. Results have been compared with volume segmentations by k-means and with two supervised methods, k-nearest neighbors and region growing. Results of individual segmentations are presented as well as comparisons on the application of the different methods to a number of tumor patient data sets.

Nanowires precisely grown on the ends of microwire electrodes permit the recording of intracellular action potentials within deeper neural structures

PubMed Central

Ferguson, John E; Boldt, Christopher; Puhl, Joshua G; Stigen, Tyler W; Jackson, Jadin C; Crisp, Kevin M; Mesce, Karen A; Netoff, Theoden I; Redish, A David

2012-01-01

Aims Nanoelectrodes are an emerging biomedical technology that can be used to record intracellular membrane potentials from neurons while causing minimal damage during membrane penetration. Current nanoelectrode designs, however, have low aspect ratios or large substrates and thus are not suitable for recording from neurons deep within complex natural structures, such as brain slices. Materials & methods We describe a novel nanoelectrode design that uses nanowires grown on the ends of microwire recording electrodes similar to those frequently used in vivo. Results & discussion We demonstrate that these nanowires can record intracellular action potentials in a rat brain slice preparation and in isolated leech ganglia. Conclusion Nanoelectrodes have the potential to revolutionize intracellular recording methods in complex neural tissues, to enable new multielectrode array technologies and, ultimately, to be used to record intracellular signals in vivo. PMID:22475650

Feasibility study on 3D image reconstruction from 2D orthogonal cine-MRI for MRI-guided radiotherapy.

PubMed

Paganelli, Chiara; Lee, Danny; Kipritidis, John; Whelan, Brendan; Greer, Peter B; Baroni, Guido; Riboldi, Marco; Keall, Paul

2018-02-11

In-room MRI is a promising image guidance strategy in external beam radiotherapy to acquire volumetric information for moving targets. However, limitations in spatio-temporal resolution led several authors to use 2D orthogonal images for guidance. The aim of this work is to present a method to concurrently compensate for non-rigid tumour motion and provide an approach for 3D reconstruction from 2D orthogonal cine-MRI slices for MRI-guided treatments. Free-breathing sagittal/coronal interleaved 2D cine-MRI were acquired in addition to a pre-treatment 3D volume in two patients. We performed deformable image registration (DIR) between cine-MRI slices and corresponding slices in the pre-treatment 3D volume. Based on an extrapolation of the interleaved 2D motion fields, the 3D motion field was estimated and used to warp the pre-treatment volume. Due to the lack of a ground truth for patients, the method was validated on a digital 4D lung phantom. On the phantom, the 3D reconstruction method was able to compensate for tumour motion and compared favourably to the results of previously adopted strategies. The difference in the 3D motion fields between the phantom and the extrapolated motion was 0.4 ± 0.3 mm for tumour and 0.8 ± 1.5 mm for whole anatomy, demonstrating feasibility of performing a 3D volumetric reconstruction directly from 2D orthogonal cine-MRI slices. Application of the method to patient data confirmed the feasibility of utilizing this method in real world scenarios. Preliminary results on phantom and patient cases confirm the feasibility of the proposed approach in an MRI-guided scenario, especially for non-rigid tumour motion compensation. © 2018 The Royal Australian and New Zealand College of Radiologists.

Distribution and characterisation of Glucagon-like peptide-1 receptor expressing cells in the mouse brain

PubMed Central

Cork, Simon C.; Richards, James E.; Holt, Marie K.; Gribble, Fiona M.; Reimann, Frank; Trapp, Stefan

2015-01-01

Objective Although Glucagon-like peptide 1 is a key regulator of energy metabolism and food intake, the precise location of GLP-1 receptors and the physiological relevance of certain populations is debatable. This study investigated the novel GLP-1R-Cre mouse as a functional tool to address this question. Methods Mice expressing Cre-recombinase under the Glp1r promoter were crossed with either a ROSA26 eYFP or tdRFP reporter strain to identify GLP-1R expressing cells. Patch-clamp recordings were performed on tdRFP-positive neurons in acute coronal brain slices from adult mice and selective targeting of GLP-1R cells in vivo was achieved using viral gene delivery. Results Large numbers of eYFP or tdRFP immunoreactive cells were found in the circumventricular organs, amygdala, hypothalamic nuclei and the ventrolateral medulla. Smaller numbers were observed in the nucleus of the solitary tract and the thalamic paraventricular nucleus. However, tdRFP positive neurons were also found in areas without preproglucagon-neuronal projections like hippocampus and cortex. GLP-1R cells were not immunoreactive for GFAP or parvalbumin although some were catecholaminergic. GLP-1R expression was confirmed in whole-cell recordings from BNST, hippocampus and PVN, where 100 nM GLP-1 elicited a reversible inward current or depolarisation. Additionally, a unilateral stereotaxic injection of a cre-dependent AAV into the PVN demonstrated that tdRFP-positive cells express cre-recombinase facilitating virally-mediated eYFP expression. Conclusions This study is a comprehensive description and phenotypic analysis of GLP-1R expression in the mouse CNS. We demonstrate the power of combining the GLP-1R-CRE mouse with a virus to generate a selective molecular handle enabling future in vivo investigation as to their physiological importance. PMID:26500843

Using normalization 3D model for automatic clinical brain quantative analysis and evaluation

NASA Astrophysics Data System (ADS)

Lin, Hong-Dun; Yao, Wei-Jen; Hwang, Wen-Ju; Chung, Being-Tau; Lin, Kang-Ping

2003-05-01

Functional medical imaging, such as PET or SPECT, is capable of revealing physiological functions of the brain, and has been broadly used in diagnosing brain disorders by clinically quantitative analysis for many years. In routine procedures, physicians manually select desired ROIs from structural MR images and then obtain physiological information from correspondent functional PET or SPECT images. The accuracy of quantitative analysis thus relies on that of the subjectively selected ROIs. Therefore, standardizing the analysis procedure is fundamental and important in improving the analysis outcome. In this paper, we propose and evaluate a normalization procedure with a standard 3D-brain model to achieve precise quantitative analysis. In the normalization process, the mutual information registration technique was applied for realigning functional medical images to standard structural medical images. Then, the standard 3D-brain model that shows well-defined brain regions was used, replacing the manual ROIs in the objective clinical analysis. To validate the performance, twenty cases of I-123 IBZM SPECT images were used in practical clinical evaluation. The results show that the quantitative analysis outcomes obtained from this automated method are in agreement with the clinical diagnosis evaluation score with less than 3% error in average. To sum up, the method takes advantage of obtaining precise VOIs, information automatically by well-defined standard 3-D brain model, sparing manually drawn ROIs slice by slice from structural medical images in traditional procedure. That is, the method not only can provide precise analysis results, but also improve the process rate for mass medical images in clinical.

Short-term field stimulation mimics synaptic maturation of hippocampal synapses

PubMed Central

Bagley, Elena E; Westbrook, Gary L

2012-01-01

Many aspects of synaptic transmission are modified during development, reflecting not only the consequence of developmental programmes of gene expression, but also the effects of ongoing neural activity. We investigated the role of synaptic activity in the maturation of Schaffer collateral (SC)–CA1 synapses using sustained low frequency field stimulation of acute brain slices. Between postnatal days 4–6 and 14–16, mouse SC–CA1 synapses in naïve slices showed a developmental decrease in the probability of transmitter release (Pr) and an increase in the contribution of GluN2A (NR2A) subunits to the NMDA receptor-mediated excitatory postsynaptic current (EPSC). Surprisingly, these developmental changes could be mimicked by short term (4 h) in vitro synaptic activity in slices taken from postnatal days (PND) 4–6 mice. However, different activity levels were required to alter release probability compared to the NMDA receptor subunit composition. Spontaneous synaptic activity was sufficient to alter the NMDA receptor subunit composition, but sustained low-frequency field stimulation of the brain slice (0.1 Hz, 4 h) was necessary to reduce release probability, as assessed 1 h following the cessation of stimulation. The protein synthesis inhibitor anisomycin blocked the effect of field stimulation on release probability. These results indicate that features of mature excitatory synapses can be rapidly induced in immature neurons. The activity dependence of the Pr and NMDA receptor subunit composition serves as a sensitive indicator of prior neural activity, and provides dual mechanisms for homeostatic control of excitatory synaptic efficacy. PMID:22351628

Short-term field stimulation mimics synaptic maturation of hippocampal synapses.

PubMed

Bagley, Elena E; Westbrook, Gary L

2012-04-01

Many aspects of synaptic transmission are modified during development, reflecting not only the consequence of developmental programmes of gene expression, but also the effects of ongoing neural activity. We investigated the role of synaptic activity in the maturation of Schaffer collateral (SC)-CA1 synapses using sustained low frequency field stimulation of acute brain slices. Between postnatal days 4-6 and 14-16, mouse SC-CA1 synapses in naïve slices showed a developmental decrease in the probability of transmitter release (P(r)) and an increase in the contribution of GluN2A (NR2A) subunits to the NMDA receptor-mediated excitatory postsynaptic current (EPSC). Surprisingly, these developmental changes could be mimicked by short term (4 h) in vitro synaptic activity in slices taken from postnatal days (PND) 4-6 mice. However, different activity levels were required to alter release probability compared to the NMDA receptor subunit composition. Spontaneous synaptic activity was sufficient to alter the NMDA receptor subunit composition, but sustained low-frequency field stimulation of the brain slice (0.1 Hz, 4 h) was necessary to reduce release probability, as assessed 1 h following the cessation of stimulation. The protein synthesis inhibitor anisomycin blocked the effect of field stimulation on release probability. These results indicate that features of mature excitatory synapses can be rapidly induced in immature neurons. The activity dependence of the P(r) and NMDA receptor subunit composition serves as a sensitive indicator of prior neural activity, and provides dual mechanisms for homeostatic control of excitatory synaptic efficacy.

AN ORGANOTYPIC UNIAXIAL STRAIN MODEL USING MICROFLUIDICS

PubMed Central

Dollé, Jean-Pierre; Morrison, Barclay; Schloss, Rene R.; Yarmush, Martin L.

2012-01-01

Traumatic brain injuries are the leading cause of disability each year in the US. The most common and devastating consequence is the stretching of axons caused by shear deformation that occurs during rotational acceleration of the brain during injury. The injury effects on axonal molecular and functional events are not fully characterized. We have developed a strain injury model that maintains the three dimensional cell architecture and neuronal networks found in vivo with the ability to visualize individual axons and their response to a mechanical injury. The advantage of this model is that it can apply uniaxial strains to axons that make functional connections between two organotypic slices and injury responses can be observed in real-time and over long term. This uniaxial strain model was designed to be capable of applying an array of mechanical strains at various rates of strain, thus replicating a range of modes of axonal injury. Long term culture, preservation of slice and cell orientation, and slice-slice connection on the device was demonstrated. The device has the ability to strain either individual axons or bundles of axons through the control of microchannel dimensions. The fidelity of the model was verified by observing characteristic responses to various strain injuries which included axonal beading, delayed elastic effects and breakdown in microtubules. Microtubule breakdown was shown to be dependent on the degree of the applied strain field, where maximal breakdown was observed at peak strain and minimal breakdown is observed at low strain. This strain injury model could be a powerful tool in assessing strain injury effects on functional axonal connections. PMID:23233120

Pusher syndrome--a frequent but little-known disturbance of body orientation perception.

PubMed

Karnath, Hans-Otto

2007-04-01

Disturbances of body orientation perception after brain lesions may specifically relate to only one dimension of space. Stroke patients with "pusher syndrome" suffer from a severe misperception of their body's orientation in the coronal (roll) plane. They experience their body as oriented 'upright' when it is in fact markedly tilted to one side. The patients use the unaffected arm or leg to actively push away from the un-paralyzed side and resist any attempt to passively correct their tilted body posture. Although pusher patients are unable to correctly determine when their own body is oriented in an upright, vertical position, they seem to have no significant difficulty in determining the orientation of the surrounding visual world in relation to their own body. Pusher syndrome is a distinctive clinical disorder occurring characteristically after unilateral left or right brain lesions in the posterior thalamus and -less frequently- in the insula and postcentral gyrus. These structures thus seem to constitute crucial neural substrates controlling human (upright) body orientation in the coronal (roll) plane. A further disturbance of body orientation that predominantly affects a single dimension of space, namely the transverse (yaw) plane, is observed in stroke patients with spatial neglect. Apparently, our brain has evolved separate neural subsystems for perceiving and controlling body orientation in different dimensions of space.

Direct mapping of 19F in 19FDG-6P in brain tissue at subcellular resolution using soft X-ray fluorescence

NASA Astrophysics Data System (ADS)

Poitry-Yamate, C.; Gianoncelli, A.; Kourousias, G.; Kaulich, B.; Lepore, M.; Gruetter, R.; Kiskinova, M.

2013-10-01

Low energy x-ray fluorescence (LEXRF) detection was optimized for imaging cerebral glucose metabolism by mapping the fluorine LEXRF signal of 19F in 19FDG, trapped as intracellular 19F-deoxyglucose-6-phosphate (19FDG-6P) at 1μm spatial resolution from 3μm thick brain slices. 19FDG metabolism was evaluated in brain structures closely resembling the general cerebral cytoarchitecture following formalin fixation of brain slices and their inclusion in an epon matrix. 2-dimensional distribution maps of 19FDG-6P were placed in a cytoarchitectural and morphological context by simultaneous LEXRF mapping of N and O, and scanning transmission x-ray (STXM) imaging. A disproportionately high uptake and metabolism of glucose was found in neuropil relative to intracellular domains of the cell body of hypothalamic neurons, showing directly that neurons, like glial cells, also metabolize glucose. As 19F-deoxyglucose-6P is structurally identical to 18F-deoxyglucose-6P, LEXRF of subcellular 19F provides a link to in vivo 18FDG PET, forming a novel basis for understanding the physiological mechanisms underlying the 18FDG PET image, and the contribution of neurons and glia to the PET signal.

Albumin elicits calcium signals from astrocytes in brain slices from neonatal rat cortex

PubMed Central

Nadal, Angel; Sul, Jai-Yoon; Valdeolmillos, Miguel; McNaughton, Peter A

1998-01-01

Albumin causes calcium signals and mitosis in cultured astrocytes, but it has not been established whether astrocytes in intact brain also respond to albumin. The effect of albumin on intracellular calcium concentration ([Ca2+]i) in single cells was therefore studied in acutely isolated cortical brain slices from the neonatal rat.Physiological concentrations of albumin from plasma and from serum produced an increase in [Ca2+]i in a subpopulation of cortical cells. Trains of transient elevations in [Ca2+]i (Ca2+ spikes) were seen in 41 % of these cells.The cells responding to albumin are identified as astrocytes because the neurone-specific agonist NMDA caused much smaller and slower responses in these cells. On the other hand NMDA-responsive cells, which are probably neurones, exhibited only small and slow responses to albumin. The residual responses of astrocytes to NMDA and neurones to albumin are likely to be due to crosstalk with adjacent neurones and astrocytes, respectively.Methanol extraction of albumin removes a polar lipid and abolishes the ability of albumin to increase intracellular calcium.Astrocyte calcium signalling caused by albumin may have important physiological consequences when the blood-brain barrier breaks down and allows albumin to enter the CNS. PMID:9596793

Blockade and knock-out of CALHM1 channels attenuate ischemic brain damage.

PubMed

Cisneros-Mejorado, Abraham; Gottlieb, Miroslav; Ruiz, Asier; Chara, Juan C; Pérez-Samartín, Alberto; Marambaud, Philippe; Matute, Carlos

2018-06-01

Overactivation of purinergic receptors during cerebral ischemia results in a massive release of neurotransmitters, including adenosine triphosphate (ATP), to the extracellular space which leads to cell death. Some hypothetical pathways of ATP release are large ion channels, such as calcium homeostasis modulator 1 (CALHM1), a membrane ion channel that can permeate ATP. Since this transmitter contributes to postischemic brain damage, we hypothesized that CALHM1 activation may be a relevant target to attenuate stroke injury. Here, we analyzed the contribution of CALHM1 to postanoxic depolarization after ischemia in cultured neurons and in cortical slices. We observed that the onset of postanoxic currents in neurons in those preparations was delayed after its blockade with ruthenium red or silencing of Calhm1 gene by short hairpin RNA, as well as in slices from CALHM1 knockout mice. Subsequently, we used transient middle cerebral artery occlusion and found that ruthenium red, a blocker of CALHM1, or the lack of CALHM1, substantially attenuated the motor symptoms and reduced significantly the infarct volume. These results show that CALHM1 channels mediate postanoxic depolarization in neurons and brain damage after ischemia. Therefore, targeting CALHM1 may have a high therapeutic potential for treating brain damage after ischemia.

Pilocarpine-Induced Status Epilepticus Increases the Sensitivity of P2X7 and P2Y1 Receptors to Nucleotides at Neural Progenitor Cells of the Juvenile Rodent Hippocampus.

PubMed

Rozmer, Katalin; Gao, Po; Araújo, Michelle G L; Khan, Muhammad Tahir; Liu, Juan; Rong, Weifang; Tang, Yong; Franke, Heike; Krügel, Ute; Fernandes, Maria José S; Illes, Peter

2017-07-01

Patch-clamp recordings indicated the presence of P2X7 receptors at neural progenitor cells (NPCs) in the subgranular zone of the dentate gyrus in hippocampal brain slices prepared from transgenic nestin reporter mice. The activation of these receptors caused inward current near the resting membrane potential of the NPCs, while P2Y1 receptor activation initiated outward current near the reversal potential of the P2X7 receptor current. Both receptors were identified by biophysical/pharmacological methods. When the brain slices were prepared from mice which underwent a pilocarpine-induced status epilepticus or when brain slices were incubated in pilocarpine-containing external medium, the sensitivity of P2X7 and P2Y1 receptors was invariably increased. Confocal microscopy confirmed the localization of P2X7 and P2Y1 receptor-immunopositivity at nestin-positive NPCs. A one-time status epilepticus in rats caused after a latency of about 5 days recurrent epileptic fits. The blockade of central P2X7 receptors increased the number of seizures and their severity. It is hypothesized that P2Y1 receptors after a status epilepticus may increase the ATP-induced proliferation/ectopic migration of NPCs; the P2X7 receptor-mediated necrosis/apoptosis might counteract these effects, which would otherwise lead to a chronic manifestation of recurrent epileptic fits. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Active uptake of substance P carboxy-terminal heptapeptide (5-11) into rat brain and rabbit spinal cord slices.

PubMed

Nakata, Y; Kusaka, Y; Yajima, H; Segawa, T

1981-12-01

We previously reported that nerve terminals and glial cells lack an active uptake system capable of terminating transmitter action of substance P (SP). In the present study, we demonstrated the existence of an active uptake system for SP carboxy-terminal heptapeptide, (5-11)SP. When the slices from either rat brain or rabbit spinal cord were incubated with [3H](5-11)SP, the uptake of (5-11)SP into slices was observed. The uptake system has the properties of an active transport mechanism: it is dependent on temperature and sensitive to hypoosmotic treatment and is inhibited by ouabain and dinitrophenol (DNP). In the brain, (5-11)SP was accumulated by means of a high-affinity and a low-affinity uptake system. The Km and the Vmax values for the high-affinity system were 4.20 x 10(-8) M and 7.59 fmol/10 mg wet weight/min, respectively, whereas these values for the low-affinity system were 1.00 x 10(-6) M and 100 fmol/10 mg wet weight/min, respectively. In the spinal cord, there was only one uptake system, with a Km value of 2.16 x 10(-7) M and Vmax value of 26.2 fmol/10 mg wet weight/min. These results suggest that when SP is released from nerve terminals, it is hydrolysed into (5-11)SP before or after acting as a neurotransmitter, which is in turn accumulated into nerve terminals. Therefore, the uptake system may represent a possible mechanism for the inactivation of SP.

Regional metabolism of Met-enkephalin and cholecystokinin on intact ratbrain slices: characterization of specific peptidases.

PubMed

Konkoy, C S; Davis, T P

1995-12-01

The metabolism of Met-enkephalin and cholecystokinin (CCK) 8-(sulfated) by intact microslices was studied in rat brain regions. Incubation of brain slices with Met-enkephalin (400 microM) resulted in a linear rate of disappearance of parent peptide and appearance of metabolic fragments whose rate of accumulation was specific to brain region. The degradative rate (pmol/min/mg of protein) of Met-enkephalin was high in caudate-putamen (5,160 +/- 120) and lower in nucleus accumbens (3,630 +/- 110) and frontal cortex (3,180 +/- 120). Inhibition of aminopeptidases decreased Met-enkephalin degradation (50-97% vs. control) in frontal cortex but was less effective in caudate-putamen (20-34%). Tyr-Gly-Gly and Phe-Met were recovered in caudate-putamen and nucleus accumbens, whereas negligible quantities of these fragments were recovered from frontal cortex. Phosphoramidon, an inhibitor of neutral endopeptidase 24.11, decreased Met-enkephalin degradation in caudate-putamen (14%) but had no effect on that in frontal cortex. A cocktail of bestatin or leuhistin (inhibitors of aminopeptidases), phosphoramidon, and captopril (an inhibitor of angiotensin converting enzyme) protected Met-enkephalin from degradation (recovery > 95%) in caudate-putamen. CCK 8-(sulfated) degradation on slices from caudate-putamen, nucleus accumbens, and frontal cortex was not altered by inhibitors of neutral endopeptidase 24.11, metalloendopeptidase 24.15, angiotensin converting enzyme, or thiol proteases. Inhibitors of either aminopeptidases or serine proteases produced small reductions (13-30%) in CCK degradation in each region. These data provide evidence for regional and structural specificity in terminating the actions of neuropeptides.

Ultrasonic evaluation of the neonatal brain.

PubMed

Johnson, M L; Rumack, C M

1980-04-01

Ultrasound examination of the infant brain has been performed in selected medical centers for many years. However, the equipment necessary for obtaining satisfactory visualization of the brain has only recently become commercially available. Currently, ultrasonography is an excellent, noninvasive, inexpensive, rapid, and safe imaging modality for the evaluation of hydrocephalus and other pathologic conditions of the neonatal brain. Ventricular size can often be evaluated in infants up to two or three years of age, but a detailed image of the brain parenchyma becomes more difficult to obtain in a term infant after the first two to three months of life. With the use of the water path and high resolution, real-time systems and with the delineation of structures by multiple projections, (axial, coronal, sagittal and occipital), complex abnormalities may be delineated.

Inhibition of astrocyte metabolism is not the primary mechanism for anaesthetic hypnosis.

PubMed

Voss, Logan J; Harvey, Martyn G; Sleigh, James W

2016-01-01

Astrocytes have been promoted as a possible mechanistic target for anaesthetic hypnosis. The aim of this study was to explore this using the neocortical brain slice preparation. The methods were in two parts. Firstly, multiple general anaesthetic compounds demonstrating varying in vivo hypnotic potency were analysed for their effect on "zero-magnesium" seizure-like event (SLE) activity in mouse neocortical slices. Subsequently, the effect of astrocyte metabolic inhibition was investigated in neocortical slices, and compared with that of the anaesthetic drugs. The rationale was that, if suppression of astrocytes was both necessary and sufficient to cause hypnosis in vivo, then inhibition of astrocytic metabolism in slices should mimic the anaesthetic effect. In vivo anaesthetic potency correlated strongly with the magnitude of reduction in SLE frequency in neocortical slices (R(2) 37.7 %, p = 0.002). Conversely, SLE frequency and length were significantly enhanced during exposure to both fluoroacetate (23 and 20 % increase, respectively, p < 0.01) and aminoadipate (12 and 38 % increase, respectively, p < 0.01 and p < 0.05). The capacity of an anaesthetic agent to reduce SLE frequency in the neocortical slice is a good indicator of its in vivo hypnotic potency. The results do not support the hypothesis that astrocytic metabolic inhibition is a mechanism of anaesthetic hypnosis.

Activation of PAF-synthesizing enzymes in rat brain stem slices after LTP induction in the medial vestibular nuclei.

PubMed

Francescangeli, Ermelinda; Grassi, Silvarosa; Pettorossi, Vito E; Goracci, Gianfrancesco

2002-11-01

LysoPAF acetyltransferase (lysoPAF-AT) and PAF-synthesizing phosphocholinetransferase (PAF-PCT) are the two enzymes which catalyze the final reactions for the synthesis of PAF. Their activities, assayed in the homogenate of rat brain stem slices and under their optimal conditions, increased 5 min after high frequency stimulation of vestibular afferents, inducing LTP in the medial vestibular nuclei. The activity of phosphatidylcholine-synthesizing phosphocholinetransferase, was not affected. Sixty minutes from the induction of LTP, PAF-PCT activity, but not that of lysoPAF-AT, was still significantly higher with respect to 5 min test stimulated control. We used AP-5 to verify whether this increase was strictly dependent upon LTP induction, which requires NMDA receptor activation. In AP-5 treated slices, lysoPAF-acetyltransferase and PAF-synthesizing phosphocholinetransferase activities increased, but they were reduced after high frequency stimulation under AP-5. In conclusion, we have demonstrated that the activities of PAF-synthesizing enzymes are activated soon after the induction of LTP and that this effect is linked to the activation of NMDA-receptors. We suggest that the enzyme activation by AP-5, preventing LTP, might be due to glutamate enhancement but, in neurons showing LTP and under normal conditions, the activation of potentiation mechanisms is critical for the enhancement of enzyme activities.

Carbachol-induced network oscillations in an in vitro limbic system brain slice.

PubMed

Lévesque, Maxime; Cataldi, Mauro; Chen, Li-Yuan; Hamidi, Shabnam; Avoli, Massimo

2017-04-21

We employed simultaneous field potential recordings from CA3, subiculum and entorhinal cortex in an in vitro brain slice preparation to understand the involvement of these limbic areas in the generation of the field potential oscillations that are induced by bath application of the muscarinic receptor agonist carbachol. Regularly spaced oscillations that mainly presented at theta frequency range (5-12Hz) occurred synchronously in all three structures in the presence of carbachol. These oscillations, which disappeared when slices were perfused with pirenzepine or with glutamatergic receptor antagonists, were categorized as short (<4s) and long (>4s) with short events oscillating at higher frequencies than long events. Field oscillations were highly synchronized between regions and latency analysis revealed that they often initiated in the entorhinal cortex later than in the other two structures. Blocking GABA A receptors modified the activity patterns of both short and long oscillations and decreased their coherence in the theta frequency range. Finally, blocking KCC2 activity disclosed a pattern of recurrent short oscillations. Our results suggest that in the presence of carbachol both subiculum and CA3 most often drive theta generators in the entorhinal cortex and that these oscillations are influenced but not abolished by altering GABA A receptor signaling. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Chronic Morphine Treatment Reduces Recovery from Opioid Desensitization

PubMed Central

Dang, Vu C.; Williams, John T.

2013-01-01

Tolerance and dependence result from long-term exposure to opioids, and there is growing evidence linking acute receptor desensitization to these more long-term processes. Receptor desensitization encompasses a series of events leading to the loss of receptor function and internalization. This study examines the onset and recovery from desensitization in locus ceruleus neurons recorded in brain slices taken from animals that have been chronically treated with morphine. After chronic morphine treatment, desensitization was altered as follows. First, the rate of desensitization was increased. Second, recovery from desensitization was always incomplete, even after a brief (1–2 min) exposure to agonist. This contrasts with experiments in controls in which recovery from desensitization, after a brief exposure to agonist, was complete within 25 min. Finally, morphine-6-β-D-glucuronide, a metabolite of morphine that was ineffective at causing desensitization in controls, induced significant desensitization in slices from morphine-treated animals. When brain slices from controls were treated with inhibitors of PKC or monensin, agents known to compromise G-protein-coupled receptor resensitization, desensitization was increased, and recovery was significantly reduced. These results indicate that receptor resensitization maintains signaling during periods of intense and sustained stimulation. After chronic morphine treatment, desensitization is potentiated, and receptor resensitization is compromised. PMID:15342737

High-resolution 3T Magnetic Resonance Imaging of the Triangular Fibrocartilage Complex in Chinese Wrists: Correlation with Cross-sectional Anatomy.

PubMed

Zhan, Hui-Li; Li, Wen-Ting; Bai, Rong-Jie; Wang, Nai-Li; Qian, Zhan-Hua; Ye, Wei; Yin, Yu-Ming

2017-04-05

The injury of the triangular fibrocartilage complex (TFCC) is a common cause of ulnar-sided wrist pain. The aim of this study was to investigate if the high-resolution 3T magnetic resonance imaging (MRI) could demonstrate the detailed complex anatomy of TFCC in Chinese. Fourteen Chinese cadaveric wrists (from four men and three women; age range at death from 30 to 60 years; mean age at 46 years) and forty healthy Chinese wrists (from 20 healthy volunteers, male/female: 10/10; age range from 21 to 53 years with a mean age of 32 years) in Beijing Jishuitan Hospital from March 2014 to March 2016 were included in this study. All cadavers and volunteers had magnetic resonance (MR) examination of the wrist with coronal T1-weighted and proton density-weighted imaging with fat suppression in three planes, respectively. MR arthrography (MRAr) was performed on one of the cadaveric wrists. Subsequently, all 14 cadaveric wrists were sliced into 2 mm thick slab with band saw (six in coronal plane, four in sagittal plane, and four in axial plane). The MRI features of normal TFCC were analyzed in these specimens and forty healthy wrists. Triangular fibrocartilage, the ulnar collateral ligament, and the meniscal homolog could be best observed on images in coronal plane. The palmar and dorsal radioulnar ligaments were best evaluated in transverse plane. The ulnotriquetral and ulnolunate ligaments were best visualized in sagittal plane. The latter two structures and the volar and dorsal capsules were better demonstrated on MRAr. High-resolution 3T MRI is capable to show the detailed complex anatomy of the TFCC and can provide valuable information for the clinical diagnosis in Chinese.

High-resolution 3T Magnetic Resonance Imaging of the Triangular Fibrocartilage Complex in Chinese Wrists: Correlation with Cross-sectional Anatomy

PubMed Central

Zhan, Hui-Li; Li, Wen-Ting; Bai, Rong-Jie; Wang, Nai-Li; Qian, Zhan-Hua; Ye, Wei; Yin, Yu-Ming

2017-01-01

Background: The injury of the triangular fibrocartilage complex (TFCC) is a common cause of ulnar-sided wrist pain. The aim of this study was to investigate if the high-resolution 3T magnetic resonance imaging (MRI) could demonstrate the detailed complex anatomy of TFCC in Chinese. Methods: Fourteen Chinese cadaveric wrists (from four men and three women; age range at death from 30 to 60 years; mean age at 46 years) and forty healthy Chinese wrists (from 20 healthy volunteers, male/female: 10/10; age range from 21 to 53 years with a mean age of 32 years) in Beijing Jishuitan Hospital from March 2014 to March 2016 were included in this study. All cadavers and volunteers had magnetic resonance (MR) examination of the wrist with coronal T1-weighted and proton density-weighted imaging with fat suppression in three planes, respectively. MR arthrography (MRAr) was performed on one of the cadaveric wrists. Subsequently, all 14 cadaveric wrists were sliced into 2 mm thick slab with band saw (six in coronal plane, four in sagittal plane, and four in axial plane). The MRI features of normal TFCC were analyzed in these specimens and forty healthy wrists. Results: Triangular fibrocartilage, the ulnar collateral ligament, and the meniscal homolog could be best observed on images in coronal plane. The palmar and dorsal radioulnar ligaments were best evaluated in transverse plane. The ulnotriquetral and ulnolunate ligaments were best visualized in sagittal plane. The latter two structures and the volar and dorsal capsules were better demonstrated on MRAr. Conclusion: High-resolution 3T MRI is capable to show the detailed complex anatomy of the TFCC and can provide valuable information for the clinical diagnosis in Chinese. PMID:28345546

Frontal slab composite magnetic resonance neurography of the brachial plexus: implications for infraclavicular block approaches.

PubMed

Raphael, David T; McIntee, Diane; Tsuruda, Jay S; Colletti, Patrick; Tatevossian, Ray

2005-12-01

Magnetic resonance neurography (MRN) is an imaging method by which nerves can be selectively highlighted. Using commercial software, the authors explored a variety of approaches to develop a three-dimensional volume-rendered MRN image of the entire brachial plexus and used it to evaluate the accuracy of infraclavicular block approaches. With institutional review board approval, MRN of the brachial plexus was performed in 10 volunteer subjects. MRN imaging was performed on a GE 1.5-tesla magnetic resonance scanner (General Electric Healthcare Technologies, Waukesha, WI) using a phased array torso coil. Coronal STIR and T1 oblique sagittal sequences of the brachial plexus were obtained. Multiple software programs were explored for enhanced display and manipulation of the composite magnetic resonance images. The authors developed a frontal slab composite approach that allows single-frame reconstruction of a three-dimensional volume-rendered image of the entire brachial plexus. Automatic segmentation was supplemented by manual segmentation in nearly all cases. For each of three infraclavicular approaches (posteriorly directed needle below midclavicle, infracoracoid, or caudomedial to coracoid), the targeting error was measured as the distance from the MRN plexus midpoint to the approach-targeted site. Composite frontal slabs (coronal views), which are single-frame three-dimensional volume renderings from image-enhanced two-dimensional frontal view projections of the underlying coronal slices, were created. The targeting errors (mean +/- SD) for the approaches-midclavicle, infracoracoid, caudomedial to coracoid-were 0.43 +/- 0.67, 0.99 +/- 1.22, and 0.65 +/- 1.14 cm, respectively. Image-processed three-dimensional volume-rendered MNR scans, which allow visualization of the entire brachial plexus within a single composite image, have educational value in illustrating the complexity and individual variation of the plexus. Suggestions for improved guidance during infraclavicular block procedures are presented.

[3D-visualization by MRI for surgical planning of Wilms tumors].

PubMed

Schenk, J P; Waag, K-L; Graf, N; Wunsch, R; Jourdan, C; Behnisch, W; Tröger, J; Günther, P

2004-10-01

To improve surgical planning of kidney tumors in childhood (Wilms tumor, mesoblastic nephroma) after radiologic verification of the presumptive diagnosis with interactive colored 3D-animation in MRI. In 7 children (1 boy, 6 girls) with a mean age of 3 years (1 month to 11 years), the MRI database (DICOM) was processed with a raycasting-based 3D-volume-rendering software (VG Studio Max 1.1/Volume Graphics). The abdominal MRI-sequences (coronal STIR, coronal T1 TSE, transverse T1/T2 TSE, sagittal T2 TSE, transverse and coronal T1 TSE post contrast) were obtained with a 0.5T unit in 4 - 6 mm slices. Additionally, a phase-contrast-MR-angiography was applied to delineate the large abdominal and retroperitoneal vessels. A notebook was used to demonstrate the 3D-visualization for surgical planning before surgery and during the surgical procedure. In all 7 cases, the surgical approach was influenced by interactive 3D-animation and the information found useful for surgical planning. Above all, the 3D-visualization demonstrates the mass effect of the Wilms tumor and its anatomical relationship to the renal hilum and to the rest of the kidney as well as the topographic relationship of the tumor to the critical vessels. One rupture of the tumor capsule occurred as a surgical complication. For the surgeon, the transformation of the anatomical situation from MRI to the surgical situs has become much easier. For surgical planning of Wilms tumors, the 3D-visualization with 3D-animation of the situs helps to transfer important information from the pediatric radiologist to the pediatric surgeon and optimizes the surgical preparation. A reduction of complications is to be expected.

Effect of surface treatments on the bond strength of CAD/CAM fiberglass posts.

PubMed

Garcia, Paula-Pontes; da Costa, Rogério-Goulart; Garcia, André-Vivan; Gonzaga, Carla-Castiglia; da Cunha, Leonardo-Fernandes; Rezende, Carlos-Eduardo-Edwards; Correr, Gisele-Maria

2018-06-01

There is no ideal protocol for the surface treatment of fiber posts, especially when using a computer-aided design/computer-aided manufacturing (CAD/CAM) experimental fiberglass block. The purpose of this study was to evaluate the bond strength of a CAD/CAM customized glass fiber post and core after applying different surface treatment techniques. Forty premolars were prepared to receive a customized CAD/CAM glass-fiber post and core obtained from an experimental block of glass fiber and epoxy resin. The specimens were randomly distributed in 4 groups (n=10) according to the post and core surface treatment: ETH - 70% ethanol; HP - 24% hydrogen peroxide for 1 minute; ETH/S - 70% ethanol + silane; HP/S - 24% hydrogen peroxide + silane. The universal adhesive containing silane was applied on the posts and prepared post spaces in all groups. The posts were cemented using dual cure resin cement. The specimens were stored in distilled water at 37°C for 24 h, cut (two slices of 1 mm for each root third - coronal, middle, and apical) and subjected to push-out test (0.5 mm/min). Data was subjected to two-way ANOVA (surface treatment and root third) and Tukey's test (α=0,05). There was no significant difference of bond strength values among groups, regardless the surface treatment ( p >0.05). There was significant difference on bond strength values for the different root thirds ( p <0.05) (coronal>middle=apical). The different surface treatment and application of additional silane in the CAD/CAM customized glass-fiber post and core does not interfere on bond strength values. The root dentin third interfered on the bond strength, with higher values for the coronal third. Key words: Post and core technique, cad/cam, shear strength, hydrogen peroxide.

Alzheimer brain-derived tau oligomers propagate pathology from endogenous tau.

PubMed

Lasagna-Reeves, Cristian A; Castillo-Carranza, Diana L; Sengupta, Urmi; Guerrero-Munoz, Marcos J; Kiritoshi, Takaki; Neugebauer, Volker; Jackson, George R; Kayed, Rakez

2012-01-01

Intracerebral injection of brain extracts containing amyloid or tau aggregates in transgenic animals can induce cerebral amyloidosis and tau pathology. We extracted pure populations of tau oligomers directly from the cerebral cortex of Alzheimer disease (AD) brain. These oligomers are potent inhibitors of long term potentiation (LTP) in hippocampal brain slices and disrupt memory in wild type mice. We observed for the first time that these authentic brain-derived tau oligomers propagate abnormal tau conformation of endogenous murine tau after prolonged incubation. The conformation and hydrophobicity of tau oligomers play a critical role in the initiation and spread of tau pathology in the naïve host in a manner reminiscent of sporadic AD.

Functional photoacoustic imaging to observe regional brain activation induced by cocaine hydrochloride

NASA Astrophysics Data System (ADS)

Jo, Janggun; Yang, Xinmai

2011-09-01

Photoacoustic microscopy (PAM) was used to detect small animal brain activation in response to drug abuse. Cocaine hydrochloride in saline solution was injected into the blood stream of Sprague Dawley rats through tail veins. The rat brain functional change in response to the injection of drug was then monitored by the PAM technique. Images in the coronal view of the rat brain at the locations of 1.2 and 3.4 mm posterior to bregma were obtained. The resulted photoacoustic (PA) images showed the regional changes in the blood volume. Additionally, the regional changes in blood oxygenation were also presented. The results demonstrated that PA imaging is capable of monitoring regional hemodynamic changes induced by drug abuse.

Adaptation of Microplate-based Respirometry for Hippocampal Slices and Analysis of Respiratory Capacity

PubMed Central

Schuh, Rosemary A.; Clerc, Pascaline; Hwang, Hyehyun; Mehrabian, Zara; Bittman, Kevin; Chen, Hegang; Polster, Brian M.

2011-01-01

Multiple neurodegenerative disorders are associated with altered mitochondrial bioenergetics. Although mitochondrial O2 consumption is frequently measured in isolated mitochondria, isolated synaptic nerve terminals (synaptosomes), or cultured cells, the absence of mature brain circuitry is a remaining limitation. Here we describe the development of a method that adapts the Seahorse Extracellular Flux Analyzer (XF24) for the microplate-based measurement of hippocampal slice O2 consumption. As a first evaluation of the technique, we compared whole slice bioenergetics to previous measurements made with synaptosomes or cultured neurons. We found that mitochondrial respiratory capacity and O2 consumption coupled to ATP synthesis could be estimated in cultured or acute hippocampal slices with preserved neural architecture. Mouse organotypic hippocampal slices oxidizing glucose displayed mitochondrial O2 consumption that was well-coupled, as determined by the sensitivity to the ATP synthase inhibitor oligomycin. However stimulation of respiration by uncoupler was modest (<120% of basal respiration) compared to previous measurements in cells or synaptosomes, although enhanced slightly (to ~150% of basal respiration) by the acute addition of the mitochondrial complex I-linked substrate pyruvate. These findings suggest a high basal utilization of respiratory capacity in slices and a limitation of glucose-derived substrate for maximal respiration. The improved throughput of microplate-based hippocampal respirometry over traditional O2 electrode-based methods is conducive to neuroprotective drug screening. When coupled with cell type-specific pharmacology or genetic manipulations, the ability to efficiently measure O2 consumption from whole slices should advance our understanding of mitochondrial roles in physiology and neuropathology. PMID:21520220

Dynamic 2D self-phase-map Nyquist ghost correction for simultaneous multi-slice echo planar imaging.

PubMed

Yarach, Uten; Tung, Yi-Hang; Setsompop, Kawin; In, Myung-Ho; Chatnuntawech, Itthi; Yakupov, Renat; Godenschweger, Frank; Speck, Oliver

2018-02-09

To develop a reconstruction pipeline that intrinsically accounts for both simultaneous multislice echo planar imaging (SMS-EPI) reconstruction and dynamic slice-specific Nyquist ghosting correction in time-series data. After 1D slice-group average phase correction, the separate polarity (i.e., even and odd echoes) SMS-EPI data were unaliased by slice GeneRalized Autocalibrating Partial Parallel Acquisition. Both the slice-unaliased even and odd echoes were jointly reconstructed using a model-based framework, extended for SMS-EPI reconstruction that estimates a 2D self-phase map, corrects dynamic slice-specific phase errors, and combines data from all coils and echoes to obtain the final images. The percentage ghost-to-signal ratios (%GSRs) and its temporal variations for MB3R y 2 with a field of view/4 shift in a human brain obtained by the proposed dynamic 2D and standard 1D phase corrections were 1.37 ± 0.11 and 2.66 ± 0.16, respectively. Even with a large regularization parameter λ applied in the proposed reconstruction, the smoothing effect in fMRI activation maps was comparable to a very small Gaussian kernel size 1 × 1 × 1 mm 3 . The proposed reconstruction pipeline reduced slice-specific phase errors in SMS-EPI, resulting in reduction of GSR. It is applicable for functional MRI studies because the smoothing effect caused by the regularization parameter selection can be minimal in a blood-oxygen-level-dependent activation map. © 2018 International Society for Magnetic Resonance in Medicine.

Circadian Regulation of Hippocampal Long-Term Potentiation

PubMed Central

Chaudhury, Dipesh; Wang, Louisa M.; Colwell, Christopher S.

2008-01-01

The goal of this study is to investigate the possible circadian regulation of hippocampal excitability and long-term potentiation (LTP) measured by stimulating the Schaffer collaterals (SC) and recording the field excitatory postsynaptic potential (fEPSP) from the CA1 dendritic layer or the population spike (PS) from the soma in brain slices of C3H and C57 mice. These 2 strains of mice were of interest because the C3H mice secrete melatonin rhythmically while the C57 mice do not. The authors found that the magnitude of the enhancement of the PS was significantly greater in LTP recorded from night slices compared to day slices of both C3H and C57 mice. They also found significant diurnal variation in the decay of LTP measured with fEPSPs, with the decay slower during the night in both strains of mice. There was evidence for a diurnal rhythm in the input/output function of pyramidal neurons measured at the soma in C57 but not C3H mice. Furthermore, LTP in the PS, measured in slices prepared during the day but recorded during the night, had a profile remarkably similar to the night group. Finally, PS recordings were carried out in slices from C3H mice maintained in constant darkness prior to experimentation. Again, the authors found that the magnitude of the enhancement of the PS was significantly greater in LTP recorded from subjective night slices compared to subjective day slices. These results provide the 1st evidence that an endogenous circadian oscillator modulates synaptic plasticity in the hippocampus. PMID:15851529

Melatonin protects against oxygen and glucose deprivation by decreasing extracellular glutamate and Nox-derived ROS in rat hippocampal slices.

PubMed

Patiño, Paloma; Parada, Esther; Farré-Alins, Victor; Molz, Simone; Cacabelos, Ramón; Marco-Contelles, José; López, Manuela G; Tasca, Carla I; Ramos, Eva; Romero, Alejandro; Egea, Javier

2016-12-01

Therapeutic interventions on pathological processes involved in the ischemic cascade, such as oxidative stress, neuroinflammation, excitotoxicity and/or apoptosis, are of urgent need for stroke treatment. Melatonin regulates a large number of physiological actions and its beneficial properties have been reported. The aim of this study was to investigate whether melatonin mediates neuroprotection in rat hippocampal slices subjected to oxygen-glucose-deprivation (OGD) and glutamate excitotoxicity. Thus, we describe here that melatonin significantly reduced the amount of lactate dehydrogenase released in the OGD-treated slices, reverted neuronal injury caused by OGD-reoxygenation in CA1 and CA3 hippocampal regions, restored the reduction of GSH content of the hippocampal slices induced by OGD, and diminished the oxidative stress produced in the reoxygenation period. Furthermore, melatonin afforded maximum protection against glutamate-induced toxicity and reversed the glutamate released almost basal levels, at 10 and 30μM concentration, respectively. Consequently, we propose that melatonin might strongly and positively influence the outcome of brain ischemia/reperfusion. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid whole-brain resting-state fMRI at 3 T: Efficiency-optimized three-dimensional EPI versus repetition time-matched simultaneous-multi-slice EPI.

PubMed

Stirnberg, Rüdiger; Huijbers, Willem; Brenner, Daniel; Poser, Benedikt A; Breteler, Monique; Stöcker, Tony

2017-12-01

State-of-the-art simultaneous-multi-slice (SMS-)EPI and 3D-EPI share several properties that benefit functional MRI acquisition. Both sequences employ equivalent parallel imaging undersampling with controlled aliasing to achieve high temporal sampling rates. As a volumetric imaging sequence, 3D-EPI offers additional means of acceleration complementary to 2D-CAIPIRINHA sampling, such as fast water excitation and elliptical sampling. We performed an application-oriented comparison between a tailored, six-fold CAIPIRINHA-accelerated 3D-EPI protocol at 530 ms temporal and 2.4 mm isotropic spatial resolution and an SMS-EPI protocol with identical spatial and temporal resolution for whole-brain resting-state fMRI at 3 T. The latter required eight-fold slice acceleration to compensate for the lack of elliptical sampling and fast water excitation. Both sequences used vendor-supplied on-line image reconstruction. We acquired test/retest resting-state fMRI scans in ten volunteers, with simultaneous acquisition of cardiac and respiration data, subsequently used for optional physiological noise removal (nuisance regression). We found that the 3D-EPI protocol has significantly increased temporal signal-to-noise ratio throughout the brain as compared to the SMS-EPI protocol, especially when employing motion and nuisance regression. Both sequence types reliably identified known functional networks with stronger functional connectivity values for the 3D-EPI protocol. We conclude that the more time-efficient 3D-EPI primarily benefits from reduced parallel imaging noise due to a higher, actual k-space sampling density compared to SMS-EPI. The resultant BOLD sensitivity increase makes 3D-EPI a valuable alternative to SMS-EPI for whole-brain fMRI at 3 T, with voxel sizes well below 3 mm isotropic and sampling rates high enough to separate dominant cardiac signals from BOLD signals in the frequency domain. Copyright © 2017 Elsevier Inc. All rights reserved.

Novel region of interest interrogation technique for diffusion tensor imaging analysis in the canine brain.

PubMed

Li, Jonathan Y; Middleton, Dana M; Chen, Steven; White, Leonard; Ellinwood, N Matthew; Dickson, Patricia; Vite, Charles; Bradbury, Allison; Provenzale, James M

2017-08-01

Purpose We describe a novel technique for measuring diffusion tensor imaging metrics in the canine brain. We hypothesized that a standard method for region of interest placement could be developed that is highly reproducible, with less than 10% difference in measurements between raters. Methods Two sets of canine brains (three seven-week-old full-brains and two 17-week-old single hemispheres) were scanned ex-vivo on a 7T small-animal magnetic resonance imaging system. Strict region of interest placement criteria were developed and then used by two raters to independently measure diffusion tensor imaging metrics within four different white-matter regions within each specimen. Average values of fractional anisotropy, radial diffusivity, and the three eigenvalues (λ1, λ2, and λ3) within each region in each specimen overall and within each individual image slice were compared between raters by calculating the percentage difference between raters for each metric. Results The mean percentage difference between raters for all diffusion tensor imaging metrics when pooled by each region and specimen was 1.44% (range: 0.01-5.17%). The mean percentage difference between raters for all diffusion tensor imaging metrics when compared by individual image slice was 2.23% (range: 0.75-4.58%) per hemisphere. Conclusion Our results indicate that the technique described is highly reproducible, even when applied to canine specimens of differing age, morphology, and image resolution. We propose this technique for future studies of diffusion tensor imaging analysis in canine brains and for cross-sectional and longitudinal studies of canine brain models of human central nervous system disease.

Influence of five home whitening gels and a remineralizing gel on the enamel and dentin ultrastructure and hardness.

PubMed

Pinheiro, Helena Burlamaqui; Cardoso, Paulo Eduardo Capel

2011-06-01

To investigate the influence of calcium phosphate enhanced home whitening agents on human enamel and dentin surface microhardness and ultramorphology. Five intact molars crowns were used for ultrastructural analysis and five for microhardness test. Each resulting coronal structure was cut in slices. After measuring baseline Knoop Hardness Number (KHN) of the enamel and dentin, the slices were divided into six experimental groups and one control (n= 5). G1= 15% carbamide peroxide (CP); G2= 16% CP; G3= Ca and PO4 (remineralizing agent); G4= 16% CP with Ca and PO4; G5= 7.5% hydrogen peroxide (HP) with Ca and PO4; G6=7.5% HP with Ca. After each daily session of treatment, specimens were stored in distilled water (37 degrees C) until the next session. Products were applied for 2 weeks, according to manufacturers' instructions. Additional KHN weredetermined. Conventional whitening agents (G1; G2) and the gel with Ca (G6), caused KHN decrease (P< 0.05).The remineralizing and whitening agents with Ca and PO4 (G3; G4; G5) did not change KHN. A change of morphology was observed on enamel and dentin surfaces in G1; G2; G5.

Segmentation of 3D ultrasound computer tomography reflection images using edge detection and surface fitting

NASA Astrophysics Data System (ADS)

Hopp, T.; Zapf, M.; Ruiter, N. V.

2014-03-01

An essential processing step for comparison of Ultrasound Computer Tomography images to other modalities, as well as for the use in further image processing, is to segment the breast from the background. In this work we present a (semi-) automated 3D segmentation method which is based on the detection of the breast boundary in coronal slice images and a subsequent surface fitting. The method was evaluated using a software phantom and in-vivo data. The fully automatically processed phantom results showed that a segmentation of approx. 10% of the slices of a dataset is sufficient to recover the overall breast shape. Application to 16 in-vivo datasets was performed successfully using semi-automated processing, i.e. using a graphical user interface for manual corrections of the automated breast boundary detection. The processing time for the segmentation of an in-vivo dataset could be significantly reduced by a factor of four compared to a fully manual segmentation. Comparison to manually segmented images identified a smoother surface for the semi-automated segmentation with an average of 11% of differing voxels and an average surface deviation of 2mm. Limitations of the edge detection may be overcome by future updates of the KIT USCT system, allowing a fully-automated usage of our segmentation approach.

Metabolism of 2-phenylethylamine and phenylacetaldehyde by precision-cut guinea pig fresh liver slices.

PubMed

Panoutsopoulos, Georgios I; Kouretas, Demetrios; Gounaris, Elias G; Beedham, Christine

2004-01-01

2-Phenylethylamine is an endogenous constituent of human brain and is implicated in cerebral transmission. It is also found in certain foodstuffs and may cause toxic side-effects in susceptible individuals. Metabolism of 2-phenylethylamine to phenylacetaldehyde is catalyzed by monoamine oxidase and the oxidation of the reactive aldehyde to its acid derivative is catalyzed mainly by aldehyde dehydrogenase and perhaps aldehyde oxidase, with xanthine oxidase having minimal transformation. The present investigation examines the metabolism of 2-phenylethylamine to phenylacetaldehyde in liver slices and compares the relative contribution of aldehyde oxidase, xanthine oxidase and aldehyde dehydrogenase activity in the oxidation of phenylacetaldehyde with precision-cut fresh liver slices in the presence/absence of specific inhibitors of each enzyme. In liver slices, phenylacetaldehyde was rapidly converted to phenylacetic acid. Phenylacetic acid was the main metabolite of 2-phenylethylamine, via the intermediate phenylacetaldehyde. Phenylacetic acid formation was completely inhibited by disulfiram (specific inhibitor of aldehyde dehydrogenase), whereas isovanillin (specific inhibitor of aldehyde oxidase) inhibited acid formation to a lesser extent and allopurinol (specific inhibitor of xanthine oxidase) had little or no effect. Therefore, in liver slices, phenylacetaldehyde is rapidly oxidized by aldehyde dehydrogenase and aldehyde oxidase with little or no contribution from xanthine oxidase.

Electrophysiology of Hypothalamic Magnocellular Neurons In vitro: A Rhythmic Drive in Organotypic Cultures and Acute Slices.

PubMed

Israel, Jean-Marc; Oliet, Stéphane H; Ciofi, Philippe

2016-01-01

Hypothalamic neurohormones are released in a pulsatile manner. The mechanisms of this pulsatility remain poorly understood and several hypotheses are available, depending upon the neuroendocrine system considered. Among these systems, hypothalamo-neurohypophyseal magnocellular neurons have been early-considered models, as they typically display an electrical activity consisting of bursts of action potentials that is optimal for the release of boluses of the neurohormones oxytocin and vasopressin. The cellular mechanisms underlying this bursting behavior have been studied in vitro, using either acute slices of the adult hypothalamus, or organotypic cultures of neonatal hypothalamic tissue. We have recently proposed, from experiments in organotypic cultures, that specific central pattern generator networks, upstream of magnocellular neurons, determine their bursting activity. Here, we have tested whether a similar hypothesis can be derived from in vitro experiments in acute slices of the adult hypothalamus. To this aim we have screened our electrophysiological recordings of the magnocellular neurons, previously obtained from acute slices, with an analysis of autocorrelation of action potentials to detect a rhythmic drive as we recently did for organotypic cultures. This confirmed that the bursting behavior of magnocellular neurons is governed by central pattern generator networks whose rhythmic drive, and thus probably integrity, is however less satisfactorily preserved in the acute slices from adult brains.

Neuronal SIRT1 (Silent Information Regulator 2 Homologue 1) Regulates Glycolysis and Mediates Resveratrol-Induced Ischemic Tolerance.

PubMed

Koronowski, Kevin B; Khoury, Nathalie; Saul, Isabel; Loris, Zachary B; Cohan, Charles H; Stradecki-Cohan, Holly M; Dave, Kunjan R; Young, Juan I; Perez-Pinzon, Miguel A

2017-11-01

Resveratrol, at least in part via SIRT1 (silent information regulator 2 homologue 1) activation, protects against cerebral ischemia when administered 2 days before injury. However, it remains unclear if SIRT1 activation must occur, and in which brain cell types, for the induction of neuroprotection. We hypothesized that neuronal SIRT1 is essential for resveratrol-induced ischemic tolerance and sought to characterize the metabolic pathways regulated by neuronal Sirt1 at the cellular level in the brain. We assessed infarct size and functional outcome after transient 60 minute middle cerebral artery occlusion in control and inducible, neuronal-specific SIRT1 knockout mice. Nontargeted primary metabolomics analysis identified putative SIRT1-regulated pathways in brain. Glycolytic function was evaluated in acute brain slices from adult mice and primary neuronal-enriched cultures under ischemic penumbra-like conditions. Resveratrol-induced neuroprotection from stroke was lost in neuronal Sirt1 knockout mice. Metabolomics analysis revealed alterations in glucose metabolism on deletion of neuronal Sirt1 , accompanied by transcriptional changes in glucose metabolism machinery. Furthermore, glycolytic ATP production was impaired in acute brain slices from neuronal Sirt1 knockout mice. Conversely, resveratrol increased glycolytic rate in a SIRT1-dependent manner and under ischemic penumbra-like conditions in vitro. Our data demonstrate that resveratrol requires neuronal SIRT1 to elicit ischemic tolerance and identify a novel role for SIRT1 in the regulation of glycolytic function in brain. Identification of robust neuroprotective mechanisms that underlie ischemia tolerance and the metabolic adaptations mediated by SIRT1 in brain are crucial for the translation of therapies in cerebral ischemia and other neurological disorders. © 2017 American Heart Association, Inc.

Evaluation of the antagonism of nicotine by mecamylamine and pempidine in the brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, T.J.

1989-01-01

Antagonists have been crucial in the characterization of nicotine's pharmacology. Initial evidence for the existence of central nicotinic receptors was based on the fact that nicotine produced a number of behavioral effects that were antagonized by ganglionic blockers that crossed the blood-brain barrier, such as mecamylamine and pempidine. These compounds are thought to be noncompetitive antagonists due to the fact that they do not compete for agonist binding to brain homogenate in vitro. However, pharmacological evidence in support of noncompetitive antagonism is lacking. Dose-response curves for nicotine were determined in the presence of various doses of pempidine for depression ofmore » spontaneous activity and antinociception in mice. Pempidine was found to shift the dose response curves for these effects of nicotine in a manner consistent with noncompetitive antagonism. A number of mecamylamine analogs were investigated for antagonism of these central effects of nicotine as well. These studies revealed that the N-, 2-, and 3-methyls were crucial for optimal efficacy and potency and suggests that these compounds possess a specific mechanism of action, possibly involving a receptor. Furthermore, the structure-activity relationships for the mecamylamine analogs were found to be different than that previously reported for the agonists, suggesting that they do not act at the same site. The binding of ({sup 3} H)-L-nicotine and ({sup 3}H)-pempidine was studied in vitro to mouse brain homogentate and in situ to rat brain slices. The in situ binding of ({sup 3}H)-L-nicotine to rat brain slices was quantitated autoradiographically to discrete brain areas in the presence and absence of 1, 10 and 100 {mu}M nicotine and pempidine. Pempidine did not effectively displace ({sup 3}H)-L-nicotine binding.« less

Transcriptome Analysis Identifies Key Metabolic Changes in the Hooded Seal (Cystophora cristata) Brain in Response to Hypoxia and Reoxygenation

PubMed Central

Czech-Damal, Nicole U.; Folkow, Lars P.

2017-01-01

The brain of diving mammals tolerates low oxygen conditions better than the brain of most terrestrial mammals. Previously, it has been demonstrated that the neurons in brain slices of the hooded seal (Cystophora cristata) withstand hypoxia longer than those of mouse, and also tolerate reduced glucose supply and high lactate concentrations. This tolerance appears to be accompanied by a shift in the oxidative energy metabolism to the astrocytes in the seal while in terrestrial mammals the aerobic energy production mainly takes place in neurons. Here, we used RNA-Seq to compare the effect of hypoxia and reoxygenation in vitro on brain slices from the visual cortex of hooded seals. We saw no general reduction of gene expression, suggesting that the response to hypoxia and reoxygenation is an actively regulated process. The treatments caused the preferential upregulation of genes related to inflammation, as found before e.g. in stroke studies using mammalian models. Gene ontology and KEGG pathway analyses showed a downregulation of genes involved in ion transport and other neuronal processes, indicative for a neuronal shutdown in response to a shortage of O2 supply. These differences may be interpreted in terms of an energy saving strategy in the seal's brain. We specifically analyzed the regulation of genes involved in energy metabolism. Hypoxia and reoxygenation caused a similar response, with upregulation of genes involved in glucose metabolism and downregulation of the components of the pyruvate dehydrogenase complex. We also observed upregulation of the monocarboxylate transporter Mct4, suggesting increased lactate efflux. Together, these data indicate that the seal brain responds to the hypoxic challenge by a relative increase in the anaerobic energy metabolism. PMID:28046118

COB231 targets amyloid plaques in post-mortem human brain tissue and in an Alzheimer mouse model.

PubMed

Garin, Dominique; Virgone-Carlotta, Angélique; Gözel, Bülent; Oukhatar, Fatima; Perret, Pascale; Marti-Battle, Danièle; Touret, Monique; Millet, Philippe; Dubois-Dauphin, Michel; Meyronet, David; Streichenberger, Nathalie; Laferla, Frank M; Demeunynck, Martine; Chierici, Sabine; Sallanon Moulin, Marcelle; Ghezzi, Catherine

2015-03-01

Previous works have shown the interest of naturally fluorescent proflavine derivatives to label Abeta deposits in vitro. This study aimed to further characterize the properties of the proflavine 3-acetylamino-6-[3-(propargylamino)propanoyl]aminoacridine (COB231) derivative as a probe. This compound was therefore evaluated on human post-mortem and mice brain slices and in vivo in 18-month-old triple transgenic mice APPswe, PS1M146V and tauP301L (3xTgAD) mice presenting the main characteristics of Alzheimer's disease (AD). COB231 labelled amyloid plaques on brain slices of AD patients, and 3xTgAD mice at 10 and 0.1 μM respectively. However, no labelling of the neurofibrillary tangle-rich areas was observed either at high concentration or in the brain of fronto-temporal dementia patients. The specificity of this mapping was attested in mice using Thioflavin S and IMPY as positive controls of amyloid deposits. After intravenous injection of COB231 in old 3xTgAD mice, fluorescent amyloid plaques were detected in the cortex and hippocampus, demonstrating COB231 blood–brain barrier permeability. We also controlled the cellular localization of COB231 on primary neuronal cultures and showed that COB231 accumulates into the cytoplasm and not into the nucleus. Finally, using a viability assay, we only detected a slight cytotoxic effect of COB231 (< 10%) for the highest concentration (100 μM).

Biofidelic white matter heterogeneity decreases computational model predictions of white matter strains during rapid head rotations.

PubMed

Maltese, Matthew R; Margulies, Susan S

2016-11-01

The finite element (FE) brain model is used increasingly as a design tool for developing technology to mitigate traumatic brain injury. We developed an ultra high-definition FE brain model (>4 million elements) from CT and MRI scans of a 2-month-old pre-adolescent piglet brain, and simulated rapid head rotations. Strain distributions in the thalamus, coronal radiata, corpus callosum, cerebral cortex gray matter, brainstem and cerebellum were evaluated to determine the influence of employing homogeneous brain moduli, or distinct experimentally derived gray and white matter property representations, where some white matter regions are stiffer and others less stiff than gray matter. We find that constitutive heterogeneity significantly lowers white matter deformations in all regions compared with homogeneous properties, and should be incorporated in FE model injury prediction.

The impact of aging, hearing loss, and body weight on mouse hippocampal redox state, measured in brain slices using fluorescence imaging.

PubMed

Stebbings, Kevin A; Choi, Hyun W; Ravindra, Aditya; Llano, Daniel Adolfo

2016-06-01

The relationships between oxidative stress in the hippocampus and other aging-related changes such as hearing loss, cortical thinning, or changes in body weight are not yet known. We measured the redox ratio in a number of neural structures in brain slices taken from young and aged mice. Hearing thresholds, body weight, and cortical thickness were also measured. We found striking aging-related increases in the redox ratio that were isolated to the stratum pyramidale, while such changes were not observed in thalamus or cortex. These changes were driven primarily by changes in flavin adenine dinucleotide, not nicotinamide adenine dinucleotide hydride. Multiple regression analysis suggested that neither hearing threshold nor cortical thickness independently contributed to this change in hippocampal redox ratio. However, body weight did independently contribute to predicted changes in hippocampal redox ratio. These data suggest that aging-related changes in hippocampal redox ratio are not a general reflection of overall brain oxidative state but are highly localized, while still being related to at least one marker of late aging, weight loss at the end of life. Copyright © 2016 Elsevier Inc. All rights reserved.

PROPYLTHIOURACIL (PTU)-INDUCED HYPOTHYROIDISM: EFFECTS ON SYNAPTIC TRANSMISSION AND LONG TERM POTENTIATION IN HIPPOCAMPAL SLICES.

EPA Science Inventory

Concern has been raised over endocrine effects of some classes of environmental chemicals. Severe hypothyroidism during critical periods of brain developmental leads to alterations in hippocampal structure, learning deficits, yet neurophysiological properties of the hippocampus...

Quantifying Mesoscale Neuroanatomy Using X-Ray Microtomography

PubMed Central

Gray Roncal, William; Prasad, Judy A.; Fernandes, Hugo L.; Gürsoy, Doga; De Andrade, Vincent; Fezzaa, Kamel; Xiao, Xianghui; Vogelstein, Joshua T.; Jacobsen, Chris; Körding, Konrad P.

2017-01-01

Methods for resolving the three-dimensional (3D) microstructure of the brain typically start by thinly slicing and staining the brain, followed by imaging numerous individual sections with visible light photons or electrons. In contrast, X-rays can be used to image thick samples, providing a rapid approach for producing large 3D brain maps without sectioning. Here we demonstrate the use of synchrotron X-ray microtomography (µCT) for producing mesoscale (∼1 µm 3 resolution) brain maps from millimeter-scale volumes of mouse brain. We introduce a pipeline for µCT-based brain mapping that develops and integrates methods for sample preparation, imaging, and automated segmentation of cells, blood vessels, and myelinated axons, in addition to statistical analyses of these brain structures. Our results demonstrate that X-ray tomography achieves rapid quantification of large brain volumes, complementing other brain mapping and connectomics efforts. PMID:29085899

Calcium Imaging of AM Dyes Following Prolonged Incubation in Acute Neuronal Tissue

PubMed Central

Morley, John W.; Tapson, Jonathan; Breen, Paul P.; van Schaik, André

2016-01-01

Calcium-imaging is a sensitive method for monitoring calcium dynamics during neuronal activity. As intracellular calcium concentration is correlated to physiological and pathophysiological activity of neurons, calcium imaging with fluorescent indicators is one of the most commonly used techniques in neuroscience today. Current methodologies for loading calcium dyes into the tissue require prolonged incubation time (45–150 min), in addition to dissection and recovery time after the slicing procedure. This prolonged incubation curtails experimental time, as tissue is typically maintained for 6–8 hours after slicing. Using a recently introduced recovery chamber that extends the viability of acute brain slices to more than 24 hours, we tested the effectiveness of calcium AM staining following long incubation periods post cell loading and its impact on the functional properties of calcium signals in acute brain slices and wholemount retinae. We show that calcium dyes remain within cells and are fully functional >24 hours after loading. Moreover, the calcium dynamics recorded >24 hrs were similar to the calcium signals recorded in fresh tissue that was incubated for <4 hrs. These results indicate that long exposure of calcium AM dyes to the intracellular cytoplasm did not alter the intracellular calcium concentration, the functional range of the dye or viability of the neurons. This data extends our previous work showing that a custom recovery chamber can extend the viability of neuronal tissue, and reliable data for both electrophysiology and imaging can be obtained >24hrs after dissection. These methods will not only extend experimental time for those using acute neuronal tissue, but also may reduce the number of animals required to complete experimental goals. PMID:27183102

Pituitary volume increase during emerging psychosis.

PubMed

Büschlen, Jeannine; Berger, Gregor E; Borgwardt, Stefan J; Aston, Jacqueline; Gschwandtner, Ute; Pflueger, Marlon O; Kuster, Pascal; Radü, Ernst Wilhem; Stieglitz, Rolf-Dieter; Riecher-Rössler, Anita

2011-01-01

Morphologic abnormalities of the pituitary gland volume (PV) have been reported in schizophrenia, but at what point in time they occur remains unclear. This study determines PV across different stages of emerging psychotic disorders compared to healthy controls. We compared PV of 36 individuals with an at-risk mental state (ARMS) for psychosis, 23 patients with a first episode psychosis (FEP) and 20 healthy controls (HC). Transition to psychosis was monitored using the BPRS transition criteria according to Yung et al. (Yung, A.R. et al., 1998. Prediction of psychosis. A step towards indicated prevention of schizophrenia. Br. J. Psychiatry Suppl. 172 (33), 14-20). Applying these transition criteria, 16 of the 36 ARMS individuals made the transition to psychosis (ARMS-T) and 20 did not (ARMS-NT). We traced PV manually on 1mm slices of magnetic resonance images in three dimensions (coronal, sagittal and axial) blind to group status. We used univariate analysis of covariance (ANCOVA) with PV as dependent variable, group and sex as between-subject factors and whole brain volume as covariate. PV increased from HC to ARMS-NT to ARMS-T/FEP. ANCOVA revealed a significant effect of group (F(3,78)=3.0; p=.036) and a sex × group interaction (F(3,78)=6.5; p=.001). Over all groups, women had considerably larger PV than men (F(1,78)=9.8; p=.003). Our findings provide further evidence that PV is increased in emerging psychotic disorders, and suggest that this is due to a stress-associated activation of the pituitary gland. Copyright © 2010 Elsevier B.V. All rights reserved.

Combined texture feature analysis of segmentation and classification of benign and malignant tumour CT slices.

PubMed

Padma, A; Sukanesh, R

2013-01-01

A computer software system is designed for the segmentation and classification of benign from malignant tumour slices in brain computed tomography (CT) images. This paper presents a method to find and select both the dominant run length and co-occurrence texture features of region of interest (ROI) of the tumour region of each slice to be segmented by Fuzzy c means clustering (FCM) and evaluate the performance of support vector machine (SVM)-based classifiers in classifying benign and malignant tumour slices. Two hundred and six tumour confirmed CT slices are considered in this study. A total of 17 texture features are extracted by a feature extraction procedure, and six features are selected using Principal Component Analysis (PCA). This study constructed the SVM-based classifier with the selected features and by comparing the segmentation results with the experienced radiologist labelled ground truth (target). Quantitative analysis between ground truth and segmented tumour is presented in terms of segmentation accuracy, segmentation error and overlap similarity measures such as the Jaccard index. The classification performance of the SVM-based classifier with the same selected features is also evaluated using a 10-fold cross-validation method. The proposed system provides some newly found texture features have an important contribution in classifying benign and malignant tumour slices efficiently and accurately with less computational time. The experimental results showed that the proposed system is able to achieve the highest segmentation and classification accuracy effectiveness as measured by jaccard index and sensitivity and specificity.

Metabolomics of Therapy Response in Preclinical Glioblastoma: A Multi-Slice MRSI-Based Volumetric Analysis for Noninvasive Assessment of Temozolomide Treatment

PubMed Central

Arias-Ramos, Nuria; Ferrer-Font, Laura; Lope-Piedrafita, Silvia; Mocioiu, Victor; Julià-Sapé, Margarida; Pumarola, Martí; Arús, Carles; Candiota, Ana Paula

2017-01-01

Glioblastoma (GBM) is the most common aggressive primary brain tumor in adults, with a short survival time even after aggressive therapy. Non-invasive surrogate biomarkers of therapy response may be relevant for improving patient survival. Previous work produced such biomarkers in preclinical GBM using semi-supervised source extraction and single-slice Magnetic Resonance Spectroscopic Imaging (MRSI). Nevertheless, GBMs are heterogeneous and single-slice studies could prevent obtaining relevant information. The purpose of this work was to evaluate whether a multi-slice MRSI approach, acquiring consecutive grids across the tumor, is feasible for preclinical models and may produce additional insight into therapy response. Nosological images were analyzed pixel-by-pixel and a relative responding volume, the Tumor Responding Index (TRI), was defined to quantify response. Heterogeneous response levels were observed and treated animals were ascribed to three arbitrary predefined groups: high response (HR, n = 2), TRI = 68.2 ± 2.8%, intermediate response (IR, n = 6), TRI = 41.1 ± 4.2% and low response (LR, n = 2), TRI = 13.4 ± 14.3%, producing therapy response categorization which had not been fully registered in single-slice studies. Results agreed with the multi-slice approach being feasible and producing an inverse correlation between TRI and Ki67 immunostaining. Additionally, ca. 7-day oscillations of TRI were observed, suggesting that host immune system activation in response to treatment could contribute to the responding patterns detected. PMID:28524099

Effects of neural stem cell media on hypoxic injury in rat hippocampal slice cultures.

PubMed

Lee, Na Mi; Chae, Soo Ahn; Lee, Hong Jun

2017-12-15

Neonatal hypoxic-ischemic brain injuries cause serious neurological sequelae, yet there is currently no effective treatment for them. We hypothesized that neurotrophic factors released into the medium by stem cells could supply hypoxia-damaged organotypic hippocampal slice cultures with regenerative abilities. We prepared organotypic slice cultures of the hippocampus of 7-day-old Sprague-Dawley rats based on the modified Stoppini method; slices were cultured for 14days in vitro using either Gahwiler's medium (G-medium) or stem cell-conditioned medium (S-medium) as culture medium. At day 14 in vitro, hippocampal slice cultures were exposed to 95% N 2 and 5% CO 2 for 3h to induce hypoxic damage, the extent of which was then measured using propidium iodide fluorescence and immunohistochemistry images. We performed dot blotting to estimate neurotrophic/growth factor levels in the G- and S-media. Organotypic hippocampal slices cultured using S-medium after hypoxic injury were significantly less damaged than those cultured using G-medium. GLUT1, NGF, GDNF, VEGF, GCSF, and IGF2 levels were higher in S-medium than in G-medium, whereas FGF1, HIF, and MCP3 levels were not significantly different between media. In conclusion, we found that stem cell-conditioned medium had a neuroprotective effect against hypoxic injury, and that, of the various neurotrophic factors in S-medium, NGF, GDNF, and VEGF can contribute to neuroprotection. Copyright © 2017 Elsevier B.V. All rights reserved.

Whole-brain high in-plane resolution fMRI using accelerated EPIK for enhanced characterisation of functional areas at 3T

PubMed Central

Yun, Seong Dae

2017-01-01

The relatively high imaging speed of EPI has led to its widespread use in dynamic MRI studies such as functional MRI. An approach to improve the performance of EPI, EPI with Keyhole (EPIK), has been previously presented and its use in fMRI was verified at 1.5T as well as 3T. The method has been proven to achieve a higher temporal resolution and smaller image distortions when compared to single-shot EPI. Furthermore, the performance of EPIK in the detection of functional signals was shown to be comparable to that of EPI. For these reasons, we were motivated to employ EPIK here for high-resolution imaging. The method was optimised to offer the highest possible in-plane resolution and slice coverage under the given imaging constraints: fixed TR/TE, FOV and acceleration factors for parallel imaging and partial Fourier techniques. The performance of EPIK was evaluated in direct comparison to the optimised protocol obtained from EPI. The two imaging methods were applied to visual fMRI experiments involving sixteen subjects. The results showed that enhanced spatial resolution with a whole-brain coverage was achieved by EPIK (1.00 mm × 1.00 mm; 32 slices) when compared to EPI (1.25 mm × 1.25 mm; 28 slices). As a consequence, enhanced characterisation of functional areas has been demonstrated in EPIK particularly for relatively small brain regions such as the lateral geniculate nucleus (LGN) and superior colliculus (SC); overall, a significantly increased t-value and activation area were observed from EPIK data. Lastly, the use of EPIK for fMRI was validated with the simulation of different types of data reconstruction methods. PMID:28945780

Regulation of Brain-Derived Neurotrophic Factor Exocytosis and Gamma-Aminobutyric Acidergic Interneuron Synapse by the Schizophrenia Susceptibility Gene Dysbindin-1.

PubMed

Yuan, Qiang; Yang, Feng; Xiao, Yixin; Tan, Shawn; Husain, Nilofer; Ren, Ming; Hu, Zhonghua; Martinowich, Keri; Ng, Julia S; Kim, Paul J; Han, Weiping; Nagata, Koh-Ichi; Weinberger, Daniel R; Je, H Shawn

2016-08-15

Genetic variations in dystrobrevin binding protein 1 (DTNBP1 or dysbindin-1) have been implicated as risk factors in the pathogenesis of schizophrenia. The encoded protein dysbindin-1 functions in the regulation of synaptic activity and synapse development. Intriguingly, a loss of function mutation in Dtnbp1 in mice disrupted both glutamatergic and gamma-aminobutyric acidergic transmission in the cerebral cortex; pyramidal neurons displayed enhanced excitability due to reductions in inhibitory synaptic inputs. However, the mechanism by which reduced dysbindin-1 activity causes inhibitory synaptic deficits remains unknown. We investigated the role of dysbindin-1 in the exocytosis of brain-derived neurotrophic factor (BDNF) from cortical excitatory neurons, organotypic brain slices, and acute slices from dysbindin-1 mutant mice and determined how this change in BDNF exocytosis transsynaptically affected the number of inhibitory synapses formed on excitatory neurons via whole-cell recordings, immunohistochemistry, and live-cell imaging using total internal reflection fluorescence microscopy. A decrease in dysbindin-1 reduces the exocytosis of BDNF from cortical excitatory neurons, and this reduction in BDNF exocytosis transsynaptically resulted in reduced inhibitory synapse numbers formed on excitatory neurons. Furthermore, application of exogenous BDNF rescued the inhibitory synaptic deficits caused by the reduced dysbindin-1 level in both cultured cortical neurons and slice cultures. Taken together, our results demonstrate that these two genes linked to risk for schizophrenia (BDNF and dysbindin-1) function together to regulate interneuron development and cortical network activity. This evidence supports the investigation of the association between dysbindin-1 and BDNF in humans with schizophrenia. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

A LED-based method for monitoring NAD(P)H and FAD fluorescence in cell cultures and brain slices.

PubMed

Rösner, Jörg; Liotta, Agustin; Schmitz, Dietmar; Heinemann, Uwe; Kovács, Richard

2013-01-30

Nicotinamide- and flavine-adenine-dinucleotides (NAD(P)H and FADH₂) are electron carriers involved in cellular energy metabolism and in a multitude of enzymatic processes. As reduced NAD(P)H and oxidised FAD molecules are fluorescent, changes in tissue auto-fluorescence provide valuable information on the cellular redox state and energy metabolism. Since fluorescence excitation, by mercury arc lamps (HBO) is inherently coupled to photo-bleaching and photo-toxicity, microfluorimetric monitoring of energy metabolism might benefit from the replacement of HBO lamps by light emitting diodes (LEDs). Here we describe a LED-based custom-built setup for monitoring NAD(P)H and FAD fluorescence at the level of single cells (HEK293) and of brain slices. We compared NAD(P)H bleaching characteristics with two light sources (HBO lamp and LED) as well as sensitivity and signal to noise ratio of three different detector types (multi-pixel photon counter (MPPC), photomultiplier tube (PMT) and photodiode). LED excitation resulted in reduced photo-bleaching at the same fluorescence output in comparison to excitation with the HBO lamp. Transiently increasing LED power resulted in reversible bleaching of NAD(P)H fluorescence. Recovery kinetics were dependent on metabolic substrates indicating coupling of NAD(P)H fluorescence to metabolism. Electrical stimulation of brain slices induced biphasic redox changes, as indicated by NAD(P)H/FAD fluorescence transients. Increasing the gain of PMT and decreasing the LED power resulted in similar sensitivity as obtained with the MPPC and the photodiode, without worsening the signal to noise ratio. In conclusion, replacement of HBO lamp with LED might improve conventional PMT based microfluorimetry of tissue auto-fluorescence. Copyright © 2012 Elsevier B.V. All rights reserved.

Brain morphology imaging by 3D microscopy and fluorescent Nissl staining.

PubMed

Lazutkin, A A; Komissarova, N V; Toptunov, D M; Anokhin, K V

2013-07-01

Modern optical methods (multiphoton and light-sheet fluorescent microscopy) allow 3D imaging of large specimens of the brain with cell resolution. It is therefore essential to refer the resultant 3D pictures of expression of transgene, protein, and other markers in the brain to the corresponding structures in the atlas. This implies counterstaining of specimens with morphological dyes. However, there are no methods for contrasting large samples of the brain without their preliminary slicing. We have developed a method for fluorescent Nissl staining of whole brain samples. 3D reconstructions of specimens of the hippocampus, olfactory bulbs, and cortex were created. The method can be used for morphological control and evaluation of the effects of various factors on the brain using 3D microscopy technique.

Tendon retraction with rotator cuff tear causes a decrease in cross-sectional area of the supraspinatus muscle on magnetic resonance imaging.

PubMed

Fukuta, Shoji; Tsutsui, Takahiko; Amari, Rui; Wada, Keizo; Sairyo, Koichi

2016-07-01

Muscle atrophy and fatty degeneration of the rotator cuff muscles have been reported as negative prognostic indicators after rotator cuff repair. Although the Y-shaped view is widely used for measuring the cross-sectional area of the supraspinatus muscle, the contribution of retraction of the torn tendon as well as muscle atrophy must be considered. The purpose of this study was to clarify the relationship between cross-sectional area and tendon retraction or size of the tear. This study included 76 shoulders that were evaluated arthroscopically for the presence and size of tears. Cross-sectional areas of rotator cuff muscles were measured from the Y-shaped view to 3 more medial slices. The occupation ratio and tangent sign were evaluated on the Y-shaped view. The retraction of torn tendon was also measured on the oblique coronal images. On the Y-shaped view, the cross-sectional area of the supraspinatus and the occupation ratio decreased in conjunction with the increase in tear size. A significant decrease in cross-sectional area was noted only in large and massive tears on more medial slices from the Y-shaped view. Significant decreases in the cross-sectional area of the infraspinatus were observed in large and massive tears on all images. A negative correlation was found between tendon retraction and cross-sectional area, which was strongest on the Y-shaped view. To avoid the influence of retraction of the supraspinatus tendon, sufficient medial slices from the musculotendinous junction should be used for evaluation of muscle atrophy. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Longitudinal change in quantitative meniscus measurements in knee osteoarthritis--data from the Osteoarthritis Initiative.

PubMed

Bloecker, Katja; Wirth, W; Guermazi, A; Hitzl, W; Hunter, D J; Eckstein, F

2015-10-01

We aimed to apply 3D MRI-based measurement technology to studying 2-year change in quantitative measurements of meniscus size and position. Forty-seven knees from the Osteoarthritis Initiative with medial radiographic joint space narrowing had baseline and 2-year follow-up MRIs. Quantitative measures were obtained from manual segmentation of the menisci and tibia using coronal DESSwe images. The standardized response mean (SRM = mean/SD change) was used as measure of sensitivity to longitudinal change. Medial tibial plateau coverage decreased from 34.8% to 29.9% (SRM -0.82; p < 0.001). Change in medial meniscus extrusion in a central image (SRM 0.18) and in the central five slices (SRM 0.22) did not reach significance, but change in extrusion across the entire meniscus (SRM 0.32; p = 0.03) and in the relative area of meniscus extrusion (SRM 0.56; p < 0.001) did. There was a reduction in medial meniscus volume (10%; p < 0.001), width (7%; p < 0.001), and height (2%; p = 0.08); meniscus substance loss was strongest in the posterior (SRM -0.51; p = 0.001) and weakest in the anterior horn (SRM -0.15; p = 0.31). This pilot study reports, for the first time, longitudinal change in quantitative 3D meniscus measurements in knee osteoarthritis. It provides evidence of improved sensitivity to change of 3D measurements compared with single slice analysis. • First longitudinal MRI-based measurements of change of meniscus position and size. • Quantitative longitudinal evaluation of meniscus change in knee osteoarthritis. • Improved sensitivity to change of 3D measurements compared with single slice analysis.

Automated segmentation of three-dimensional MR brain images

NASA Astrophysics Data System (ADS)

Park, Jonggeun; Baek, Byungjun; Ahn, Choong-Il; Ku, Kyo Bum; Jeong, Dong Kyun; Lee, Chulhee

2006-03-01

Brain segmentation is a challenging problem due to the complexity of the brain. In this paper, we propose an automated brain segmentation method for 3D magnetic resonance (MR) brain images which are represented as a sequence of 2D brain images. The proposed method consists of three steps: pre-processing, removal of non-brain regions (e.g., the skull, meninges, other organs, etc), and spinal cord restoration. In pre-processing, we perform adaptive thresholding which takes into account variable intensities of MR brain images corresponding to various image acquisition conditions. In segmentation process, we iteratively apply 2D morphological operations and masking for the sequences of 2D sagittal, coronal, and axial planes in order to remove non-brain tissues. Next, final 3D brain regions are obtained by applying OR operation for segmentation results of three planes. Finally we reconstruct the spinal cord truncated during the previous processes. Experiments are performed with fifteen 3D MR brain image sets with 8-bit gray-scale. Experiment results show the proposed algorithm is fast, and provides robust and satisfactory results.

Preclinical Evaluation of 18F-JNJ64349311, a Novel PET Tracer for Tau Imaging.

PubMed

Declercq, Lieven; Rombouts, Frederik; Koole, Michel; Fierens, Katleen; Mariën, Jonas; Langlois, Xavier; Andrés, José Ignacio; Schmidt, Mark; Macdonald, Gregor; Moechars, Diederik; Vanduffel, Wim; Tousseyn, Thomas; Vandenberghe, Rik; Van Laere, Koen; Verbruggen, Alfons; Bormans, Guy

2017-06-01

In this study, we have synthesized and evaluated 18 F-JNJ64349311, a tracer with high affinity for aggregated tau (inhibition constant value, 8 nM) and high (≥500×) in vitro selectivity for tau over β-amyloid, in comparison with the benchmark compound 18 F-AV1451 ( 18 F-T807) in mice, rats, and a rhesus monkey. Methods: In vitro binding characteristics were determined for Alzheimer's disease, progressive supranuclear palsy, and corticobasal degeneration patient brain tissue slices using autoradiography studies. Ex vivo biodistribution studies were performed in mice. Radiometabolites were quantified in the brain and plasma of mice and in the plasma of a rhesus monkey using high-performance liquid chromatography. Dynamic small-animal PET studies were performed in rats and a rhesus monkey to evaluate tracer pharmacokinetics in the brain. Results: Mouse biodistribution studies showed moderate initial brain uptake and rapid brain washout. Radiometabolite analyses after injection of 18 F-JNJ64349311 in mice showed the presence of a polar radiometabolite in plasma, but not in the brain. Semiquantitative autoradiography studies on postmortem tissue sections of human Alzheimer's disease brains showed highly displaceable binding to tau-rich regions. No specific binding was, however, found on human progressive supranuclear palsy and corticobasal degeneration brain slices. Small-animal PET scans of Wistar rats revealed moderate initial brain uptake (SUV, ∼1.5 at 1 min after injection) and rapid brain washout. Gradual bone uptake was, however, also observed. Blocking and displacement did not affect brain time-activity curves, suggesting no off-target specific binding of the tracer in the healthy rat brain. A small-animal PET scan of a rhesus monkey revealed moderate initial brain uptake (SUV, 1.9 at 1 min after injection) with a rapid washout. In the monkey, no bone uptake was detected during the 120-min scan. Conclusion: This biologic evaluation suggests that 18 F-JNJ64349311 is a promising tau PET tracer candidate, with a favorable pharmacokinetic profile, as compared with 18 F-AV1451. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Localizing Visual Function in the Brain

DTIC Science & Technology

1992-08-13

fec, 93-16707 FIELO GROUP SUB. GR. 9. AUSTRACT lCadouhn as en wierg if wcooemar end idenatfy 67 bloeS squoIbofD A three day meeting, held in Rochester...were unaware of using radiolabelled agents or optical imaging in macaque monkeys. This meeting introduced many scientists to other researchers and...paramagnetic contrast agent injected into a vein. The relative blood volume in a slice of the brain can thus be deduced, and changes in blood volume

Inhomogeneity in optical properties of rat brain: a study for LLLT dosimetry

NASA Astrophysics Data System (ADS)

Sousa, Marcelo V. P.; Prates, Renato; Kato, Ilka T.; Sabino, Caetano P.; Yoshimura, Tania M.; Suzuki, Luis C.; Magalhães, Ana C.; Yoshimura, Elisabeth M.; Ribeiro, Martha S.

2013-03-01

Over the last few years, low-level light therapy (LLLT) has shown an incredible suitability for a wide range of applications for central nervous system (CNS) related diseases. In this therapeutic modality light dosimetry is extremely critical so the study of light propagation through the CNS organs is of great importance. To better understand how light intensity is delivered to the most relevant neural sites we evaluated optical transmission through slices of rat brain point by point. We experimented red (λ = 660 nm) and near infrared (λ = 808 nm) diode laser light analyzing the light penetration and distribution in the whole brain. A fresh Wistar rat (Rattus novergicus) brain was cut in sagittal slices and illuminated with a broad light beam. A high-resolution digital camera was employed to acquire data of transmitted light. Spatial profiles of the light transmitted through the sample were obtained from the images. Peaks and valleys in the profiles show sites where light was less or more attenuated. The peak intensities provide information about total attenuation and the peak widths are correlated to the scattering coefficient at that individual portion of the sample. The outcomes of this study provide remarkable information for LLLT dose-dependent studies involving CNS and highlight the importance of LLLT dosimetry in CNS organs for large range of applications in animal and human diseases.

Characteristics of taurine release in slices from adult and developing mouse brain stem.

PubMed

Saransaari, P; Oja, S S

2006-07-01

Taurine has been thought to function as a regulator of neuronal activity, neuromodulator and osmoregulator. Moreover, it is essential for the development and survival of neural cells and protects them under cell-damaging conditions. Taurine is also involved in many vital functions regulated by the brain stem, including cardiovascular control and arterial blood pressure. The release of taurine has been studied both in vivo and in vitro in higher brain areas, whereas the mechanisms of release have not been systematically characterized in the brain stem. The properties of release of preloaded [(3)H]taurine were now characterized in slices prepared from the mouse brain stem from developing (7-day-old) and young adult (3-month-old) mice, using a superfusion system. In general, taurine release was found to be similar to that in other brain areas, consisting of both Ca(2+)-dependent and Ca(2+)-independent components. Moreover, the release was mediated by Na(+)-, Cl(-)-dependent transporters operating outwards, as both Na(+)-free and Cl(-) -free conditions greatly enhanced it. Cl(-) channel antagonists and a Cl(-) transport inhibitor reduced the release at both ages, indicating that a part of the release occurs through ion channels. Protein kinases appeared not to be involved in taurine release in the brain stem, since substances affecting the activity of protein kinase C or tyrosine kinase had no significant effects. The release was modulated by cAMP second messenger systems and phospholipases at both ages. Furthermore, the metabotropic glutamate receptor agonists likewise suppressed the K(+)-stimulated release at both ages. In the immature brain stem, the ionotropic glutamate receptor agonists N-methyl-D-aspartate (NMDA) and 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) potentiated taurine release in a receptor-mediated manner. This could constitute an important mechanism against excitotoxicity, protecting the brain stem under cell-damaging conditions.

Mitochondrial uncoupling agents antagonize rotenone actions in rat substantia nigra dopamine neurons.

PubMed

Wu, Yan-Na; Munhall, Adam C; Johnson, Steven W

2011-06-13

Mild uncoupling of oxidative phosphorylation has been reported to reduce generation of reactive oxygen species (ROS) and therefore may be neuroprotective. We reported previously that the mitochondrial poison rotenone enhanced currents evoked by N-methyl-D-aspartate (NMDA) by a ROS-dependent mechanism in rat midbrain dopamine neurons. Thus, rotenone, which produces a model of Parkinson's disease in rodents, may increase the risk of dopamine neuron excitotoxicity. The purpose of this study was to test the hypothesis that oxidative phosphorylation uncoupling agents would antagonize the effect of rotenone on NMDA current. We used patch pipettes to record whole-cell currents under voltage-clamp (-60 mV) in substantia nigra dopamine neurons in slices of rat brain. Rotenone, NMDA and uncoupling agents were added to the brain slice superfusate. Inward currents evoked by NMDA (30 μM) more than doubled in amplitude after slices were superfused for 30 min with 100 nM rotenone. Continuous superfusion with the uncoupling agent carbonyl cyanide-p-trifluoromethoxy-phenylhydrazone (1-3 nM) or 2,4-dinitrophenol (100 nM) significantly antagonized and delayed the ability of rotenone to potentiate NMDA currents. Coenzyme Q₁₀ (1-10 nM), which has been reported to facilitate uncoupling protein activity, also antagonized this action of rotenone. These results suggest that mild uncoupling of oxidative phosphorylation may protect dopamine neurons against injury from mitochondrial poisons such as rotenone. Published by Elsevier B.V.

Neuropeptide metabolism on intact, regional brain slices: effect of dopaminergic agents on substance P, cholecystokinin and Met-enkephalin degradation.

PubMed

Waters, S M; Konkoy, C S; Davis, T P

1995-08-01

Neuroleptic drugs have been shown to affect the level and messenger ribonucleic acid of specific neuropeptides. The effect of subchronically administered neuroleptics on neuropeptide metabolism, however, has not been systematically characterized. In the present study, the effect of neuroleptics and other dopaminergic compounds on substance P (SP), cholecystokinin and met-enkephalin degradation was determined on intact, regional, rat brain slices. After 7-day administration of haloperidol (1 mg/kg) or chlorpromazine (20 mg/kg), SP degradation was decreased in caudate-putamen and nucleus accumbens. After administration of the dopaminergic agonist apomorphine (5 mg/kg, b.i.d.), SP degradation was increased in the nucleus accumbens. The dopamine D2-receptor antagonist sulpiride (100 mg/kg, b.i.d.) produced no effect on SP degradation. Met-enkephalin degradation was decreased after haloperidol administration in both frontal cortex and caudate-putamen and unaffected by apomorphine administration. The metabolism of cholecystokinin was not affected by neuroleptic treatment. Studies performed with specific peptidase inhibitors suggested that neutral endopeptidase 24.11, metalloendopeptidase 24.15 and aminopeptidases degrade SP on caudate-putamen and nucleus accumbens slices. Therefore, alterations in these peptidases may be responsible for the change noted in SP degradation after dopaminergic compound administration. These metabolic changes noted after neuroleptic administration may therefore contribute to neuroleptic-induced alterations in regional peptide levels.

Optical slicing and 3-D characterization of hippocampal capillaries in the rat visualized by autometallographic silver enhancement of colloidal gold particles.

PubMed

Andreasen, A; Danscher, G

1997-10-01

In order to visualize the vascular system of the rat brain, 10 Wistar rats were perfused transcardially with glutaraldehyde and a 40 degrees C gold-gelatine solution. The brains were post-fixed with glutaraldehyde and vibratomized into 100-micron-thick slices, and the gold particles were developed by autometallography. In this way, the colloidal gold particles in the vessels became encased in silver and thereby made visible. The developed gold staining is stable and does not interfere with further dehydration and counterstaining. Images were frame grabbed during optical slicing, and classic stereograms and 'shadow' 3-D images were produced. We found a high variation of capillary density in the hippocampal region reflecting known subregional structures. The silver-enhanced vessels acted as natural markers and made it possible to study and measure aspects of the complexity of dehydration and staining artifacts. We found a non-linear shrinking of 13-17% in the x- and y-directions and a spatial shrinking up to 50% in some regions after the dehydration and staining process. This observation may be of interest not only in relation to tissue subjected to this fixation protocol but also to other fixation procedures. The gold-gelatine autometallographic technique and the present stereograms can release data for stereological use as well.

Stimulation of estradiol biosynthesis by tributyltin in rat hippocampal slices.

PubMed

Munetsuna, Eiji; Hattori, Minoru; Yamazaki, Takeshi

2014-01-01

Hippocampal functions are influenced by steroid hormones, such as testosterone and estradiol. It has been demonstrated that hippocampus-derived steroid hormones play important roles in neuronal protection and synapse formation. Our research groups have demonstrated that estradiol is de novo synthesized in the rat hippocampus. However, the mechanism(s) regulating this synthesis remains unclear. It has been reported that tributyltin, an environmental pollutant, binds to the retinoid X receptor (RXR) and modifies estrogen synthesis in human granulosa-like tumor cells. This compound can penetrate the blood brain barrier, and tends to accumulate in the brain. Based on these facts, we hypothesized that tributyltin could influence the hippocampal estradiol synthesis. A concentration of 0.1 μM tributyltin induced an increase in the mRNA content of P450(17α) and P450arom in hippocampal slices, as determined using real-time PCR. The transcript levels of other steroidogenic enzymes and a steroidogenic acute regulatory protein were not affected. The estradiol level in rat hippocampal slices was subsequently determined using a radioimmunoassay. We found that the estradiol synthesis was stimulated by ∼2-fold following a 48-h treatment with 0.1 μM tributyltin, and this was accompanied by transcriptional activation of P450(17α) and P450arom. Tributyltin stimulated de novo hippocampal estradiol synthesis by modifying the transcription of specific steroidogenic enzymes.

Tissue specific resonance frequencies of water and metabolites within the human brain

NASA Astrophysics Data System (ADS)

Chadzynski, Grzegorz L.; Bender, Benjamin; Groeger, Adriane; Erb, Michael; Klose, Uwe

2011-09-01

Chemical shift imaging (CSI) without water suppression was used to examine tissue-specific resonance frequencies of water and metabolites within the human brain. The aim was to verify if there are any regional differences in those frequencies and to determine the influence of chemical shift displacement in slice-selection direction. Unsuppressed spectra were acquired at 3 T from nine subjects. Resonance frequencies of water and after water signal removal of total choline, total creatine and NAA were estimated. Furthermore, frequency distances between the water and those resonances were calculated. Results were corrected for chemical shift displacement. Frequency distances between water and metabolites were consistent and greater for GM than for WM. The highest value of WM to GM difference (14 ppb) was observed for water to NAA frequency distance. This study demonstrates that there are tissue-specific differences between frequency distances of water and metabolites. Moreover, the influence of chemical shift displacement in slice-selection direction is showed to be negligible.

Tissue specific resonance frequencies of water and metabolites within the human brain.

PubMed

Chadzynski, Grzegorz L; Bender, Benjamin; Groeger, Adriane; Erb, Michael; Klose, Uwe

2011-09-01

Chemical shift imaging (CSI) without water suppression was used to examine tissue-specific resonance frequencies of water and metabolites within the human brain. The aim was to verify if there are any regional differences in those frequencies and to determine the influence of chemical shift displacement in slice-selection direction. Unsuppressed spectra were acquired at 3T from nine subjects. Resonance frequencies of water and after water signal removal of total choline, total creatine and NAA were estimated. Furthermore, frequency distances between the water and those resonances were calculated. Results were corrected for chemical shift displacement. Frequency distances between water and metabolites were consistent and greater for GM than for WM. The highest value of WM to GM difference (14ppb) was observed for water to NAA frequency distance. This study demonstrates that there are tissue-specific differences between frequency distances of water and metabolites. Moreover, the influence of chemical shift displacement in slice-selection direction is showed to be negligible. Copyright © 2011 Elsevier Inc. All rights reserved.

Ketamine attenuates the glutamatergic neurotransmission in the ventral posteromedial nucleus slices of rats.

PubMed

Fu, Bao; Liu, Chengxi; Zhang, Yajun; Fu, Xiaoyun; Zhang, Lin; Yu, Tian

2017-08-23

Ketamine is a frequently used intravenous anesthetic, which can reversibly induce loss of consciousness (LOC). Previous studies have demonstrated that thalamocortical system is critical for information transmission and integration in the brain. The ventral posteromedial nucleus (VPM) is a critical component of thalamocortical system. Glutamate is an important excitatory neurotransmitter in the brain and may be involved in ketamine-induced LOC. The study used whole-cell patch-clamp to observe the effect of ketamine (30 μM-1000 μM) on glutamatergic neurotransmission in VPM slices. Ketamine significantly decreased the amplitude of glutamatergic spontaneous excitatory postsynaptic currents (sEPSCs), but only higher concentration of ketamine (300 μM and 1000 μM) suppressed the frequency of sEPSCs. Ketamine (100 μM-1000 μM) also decreased the amplitude of glutamatergic miniature excitatory postsynaptic currents (mEPSCs), without altering the frequency. In VPM neurons, ketamine attenuates the glutamatergic neurotransmission mainly through postsynaptic mechanism and action potential may be involved in the process.

Time- and dose-dependent changes in neuronal activity produced by X radiation in brain slices.

PubMed

Pellmar, T C; Schauer, D A; Zeman, G H

1990-05-01

A new method of exposing tissues to X rays in a lead Faraday cage has made it possible to examine directly radiation damage to isolated neuronal tissue. Thin slices of hippocampus from brains of euthanized guinea pigs were exposed to 17.4 ke V X radiation. Electrophysiological recordings were made before, during, and after exposure to doses between 5 and 65 Gy at a dose rate of 1.54 Gy/min. Following exposure to doses of 40 Gy and greater, the synaptic potential was enhanced, reaching a steady level soon after exposure. The ability of the synaptic potential to generate a spike was reduced and damage progressed after termination of the radiation exposure. Recovery was not observed following termination of exposure. These results demonstrate that an isolated neuronal network can show complex changes in electrophysiological properties following moderate doses of ionizing radiation. An investigation of radiation damage directly to neurons in vitro will contribute to the understanding of the underlying mechanisms of radiation-induced nervous system dysfunction.

Synthetic Minority Oversampling Technique and Fractal Dimension for Identifying Multiple Sclerosis

NASA Astrophysics Data System (ADS)

Zhang, Yu-Dong; Zhang, Yin; Phillips, Preetha; Dong, Zhengchao; Wang, Shuihua

Multiple sclerosis (MS) is a severe brain disease. Early detection can provide timely treatment. Fractal dimension can provide statistical index of pattern changes with scale at a given brain image. In this study, our team used susceptibility weighted imaging technique to obtain 676 MS slices and 880 healthy slices. We used synthetic minority oversampling technique to process the unbalanced dataset. Then, we used Canny edge detector to extract distinguishing edges. The Minkowski-Bouligand dimension was a fractal dimension estimation method and used to extract features from edges. Single hidden layer neural network was used as the classifier. Finally, we proposed a three-segment representation biogeography-based optimization to train the classifier. Our method achieved a sensitivity of 97.78±1.29%, a specificity of 97.82±1.60% and an accuracy of 97.80±1.40%. The proposed method is superior to seven state-of-the-art methods in terms of sensitivity and accuracy.

Response of avian embryonic brain to spatially segmented x-ray microbeams.

PubMed

Dilmanian, F A; Morris, G M; Le Duc, G; Huang, X; Ren, B; Bacarian, T; Allen, J C; Kalef-Ezra, J; Orion, I; Rosen, E M; Sandhu, T; Sathé, P; Wu, X Y; Zhong, Z; Shivaprasad, H L

2001-05-01

Duck embryo was studied as a model for assessing the effects of microbeam radiation therapy (MRT) on the human infant brain. Because of the high risk of radiation-induced disruption of the developmental process in the immature brain, conventional wide-beam radiotherapy of brain tumors is seldom carried out in infants under the age of three. Other types of treatment for pediatric brain tumors are frequently ineffective. Recent findings from studies in Grenoble on the brain of suckling rats indicate that MRT could be of benefit for the treatment of early childhood tumors. In our studies, duck embryos were irradiated at 3-4 days prior to hatching. Irradiation was carried out using a single exposure of synchrotron-generated X-rays, either in the form of parallel microplanar beams (microbeams), or as non-segmented broad beam. The individual microplanar beams had a width of 27 microm and height of 11 mm, and a center-to-center spacing of 100 microm. Doses to the exposed areas of embryo brain were 40, 80, 160 and 450 Gy (in-slice dose) for the microbeam, and 6, 12 and 18 Gy for the broad beam. The biological end point employed in the study was ataxia. This neurological symptom of radiation damage to the brain developed within 75 days of hatching. Histopathological analysis of brain tissue did not reveal any radiation induced lesions for microbeam doses of 40-160 Gy (in-slice), although some incidences of ataxia were observed in that dose group. However, severe brain lesions did occur in animals in the 450 Gy microbeam dose groups, and mild lesions in the 18 Gy broad beam dose group. These results indicate that embryonic duck brain has an appreciably higher tolerance to the microbeam modality, as compared to the broad beam modality. When the microbeam dose was normalized to the full volume of the irradiated tissue. i.e., the dose averaged over microbeams and the space between the microbeams, brain tolerance was estimated to be about three times higher to microbeam irradiation as compared with broad beam irradiation.

Three-dimensional atlas of iron, copper, and zinc in the mouse cerebrum and brainstem.

PubMed

Hare, Dominic J; Lee, Jason K; Beavis, Alison D; van Gramberg, Amanda; George, Jessica; Adlard, Paul A; Finkelstein, David I; Doble, Philip A

2012-05-01

Atlases depicting molecular and functional features of the brain are becoming an integral part of modern neuroscience. In this study we used laser ablation-inductively coupled plasma-mass spectrometry (LA-ICPMS) to quantitatively measure iron (Fe), copper (Cu), and zinc (Zn) levels in a serially sectioned C57BL/6 mouse brain (cerebrum and brainstem). Forty-six sections were analyzed in a single experiment of approximately 158 h in duration. We constructed a 46-plate reference atlas by aligning quantified images of metal distribution with corresponding coronal sections from the Allen Mouse Brain Reference Atlas. The 46 plates were also used to construct three-dimensional models of Fe, Cu, and Zn distribution. This atlas represents the first reconstruction of quantitative trace metal distribution through the brain by LA-ICPMS and will facilitate the study of trace metals in the brain and help to elucidate their role in neurobiology.

Preliminary Study of Realistic Blast Impact on Cultured Brain Slices

DTIC Science & Technology

2015-04-01

and/or multiple impacts in water. 3. Experimental Setup 3.1 The Aquarium Setup A 30.5-cm by 34.5- × 65-cm water-filled polymethylmethacrylate ...sodium bicarbonate PAGE polyacrylamide gel electrophoresis PMMA polymethylmethacrylate RDECOM U.S. Army Research Development and Engineering Command

Neurological Consequences of Acute and Chronic Cholinergic Blockage.

DTIC Science & Technology

1986-06-02

THIP) and baclofen elicit hyperpolarization when applied to the dendritic layer (Alger and Nicoll, 1982b; Thalmann and Hershkowitz, 1985). Alger and...P.L.: Pre- and postsynaptic effects of baclofen in the rat hippocampal slice. Brain Res. 341: 195-199, 1985. Chan-Palay, V.: Quantitative visualization

Phosphatase inhibitors remove the run-down of γ-aminobutyric acid type A receptors in the human epileptic brain

PubMed Central

Palma, E.; Ragozzino, D. A.; Di Angelantonio, S.; Spinelli, G.; Trettel, F.; Martinez-Torres, A.; Torchia, G.; Arcella, A.; Di Gennaro, G.; Quarato, P. P.; Esposito, V.; Cantore, G.; Miledi, R.; Eusebi, F.

2004-01-01

The properties of γ-aminobutyric acid (GABA) type A receptors (GABAA receptors) microtransplanted from the human epileptic brain to the plasma membrane of Xenopus oocytes were compared with those recorded directly from neurons, or glial cells, in human brains slices. Cell membranes isolated from brain specimens, surgically obtained from six patients afflicted with drug-resistant temporal lobe epilepsy (TLE) were injected into frog oocytes. Within a few hours, these oocytes acquired GABAA receptors that generated GABA currents with an unusual run-down, which was inhibited by orthovanadate and okadaic acid. In contrast, receptors derived from membranes of a nonepileptic hippocampal uncus, membranes from mouse brain, or recombinant rat α1β2γ2-GABA receptors exhibited a much less pronounced GABA-current run-down. Moreover, the GABAA receptors of pyramidal neurons in temporal neocortex slices from the same six epileptic patients exhibited a stronger run-down than the receptors of rat pyramidal neurons. Interestingly, the GABAA receptors of neighboring glial cells remained substantially stable after repetitive activation. Therefore, the excessive GABA-current run-down observed in the membrane-injected oocytes recapitulates essentially what occurs in neurons, rather than in glial cells. Quantitative RT-PCR analyses from the same TLE neocortex specimens revealed that GABAA-receptor β1, β2, β3, and γ2 subunit mRNAs were significantly overexpressed (8- to 33-fold) compared with control autopsy tissues. Our results suggest that an abnormal GABA-receptor subunit transcription in the TLE brain leads to the expression of run-down-enhanced GABAA receptors. Blockage of phosphatases stabilizes the TLE GABAA receptors and strengthens GABAergic inhibition. It may be that this process can be targeted to develop new treatments for intractable epilepsy. PMID:15218107

Automatic Semantic Segmentation of Brain Gliomas from MRI Images Using a Deep Cascaded Neural Network.

PubMed

Cui, Shaoguo; Mao, Lei; Jiang, Jingfeng; Liu, Chang; Xiong, Shuyu

2018-01-01

Brain tumors can appear anywhere in the brain and have vastly different sizes and morphology. Additionally, these tumors are often diffused and poorly contrasted. Consequently, the segmentation of brain tumor and intratumor subregions using magnetic resonance imaging (MRI) data with minimal human interventions remains a challenging task. In this paper, we present a novel fully automatic segmentation method from MRI data containing in vivo brain gliomas. This approach can not only localize the entire tumor region but can also accurately segment the intratumor structure. The proposed work was based on a cascaded deep learning convolutional neural network consisting of two subnetworks: (1) a tumor localization network (TLN) and (2) an intratumor classification network (ITCN). The TLN, a fully convolutional network (FCN) in conjunction with the transfer learning technology, was used to first process MRI data. The goal of the first subnetwork was to define the tumor region from an MRI slice. Then, the ITCN was used to label the defined tumor region into multiple subregions. Particularly, ITCN exploited a convolutional neural network (CNN) with deeper architecture and smaller kernel. The proposed approach was validated on multimodal brain tumor segmentation (BRATS 2015) datasets, which contain 220 high-grade glioma (HGG) and 54 low-grade glioma (LGG) cases. Dice similarity coefficient (DSC), positive predictive value (PPV), and sensitivity were used as evaluation metrics. Our experimental results indicated that our method could obtain the promising segmentation results and had a faster segmentation speed. More specifically, the proposed method obtained comparable and overall better DSC values (0.89, 0.77, and 0.80) on the combined (HGG + LGG) testing set, as compared to other methods reported in the literature. Additionally, the proposed approach was able to complete a segmentation task at a rate of 1.54 seconds per slice.

Protective Effects of Chlorogenic Acid and its Metabolites on Hydrogen Peroxide-Induced Alterations in Rat Brain Slices: A Comparative Study with Resveratrol.

PubMed

Gul, Zulfiye; Demircan, Celaleddin; Bagdas, Deniz; Buyukuysal, Rifat Levent

2016-08-01

The effectiveness of chlorogenic acid and its main metabolites, caffeic and quinic acids, against oxidative stress was investigated. Resveratrol, another natural phenolic compound, was also tested for comparison. Rat cortical slices were incubated with 200 μM H2O2 for 1 h, and alterations in oxidative stress parameters, such as 2, 3, 5-triphenyltetrazolium chloride (TTC) staining and the production of both malondialdehyde (MDA) and reactive oxygen species (ROS), were assayed in the absence or presence of phenolic compounds. Additionally, the effectiveness of chlorogenic acid and other compounds on H2O2-induced increases in fluorescence intensities were also compared in slice-free incubation medium. Although quinic acid failed, chlorogenic and caffeic acids significantly ameliorated the H2O2-induced decline in TTC staining intensities. Although resveratrol also caused an increase in staining intensity, its effect was not dose-dependent; the high concentrations of resveratrol tested in the present study (10 and 100 μM) further lessened the staining of the slices. Additionally, all phenolic compounds significantly attenuated the H2O2-induced increases in MDA and ROS levels in cortical slices. When the IC50 values were compared to H2O2-induced alterations, chlorogenic acid was more potent than either its metabolites or resveratrol for all parameters studied under these experimental conditions. In slice-free experimental conditions, on the other hand, chlorogenic and caffeic acids significantly attenuated the fluorescence emission enhanced by H2O2 with a similar order of potency to that obtained in slice-containing physiological medium. These results indicate that chlorogenic acid is a more potent phenolic compound than resveratrol and its main metabolites caffeic and quinic acids against H2O2-induced alterations in oxidative stress parameters in rat cortical slices.

An Audit to Evaluate the Image Quality of Magnetic Resonance of Knee at Radiology Department of a Tertiary Care Hospital.

PubMed

Mansoor, Ali; Ramzan, Amaila; Chaudhary, Aamer Nadeem

2017-04-01

light of recommendations of ACR. Aclinical audit. Department of Radiology, Jinnah Hospital, Lahore, from August 2015 to February 2016. Scans of 20 patients who underwent MRI of knee in August 2015 were studied retrospectively to assess the quality of images obtained in the first audit. Based on the findings of this audit, recommendations were made and re audit was done 6 months later in February 2016 to look for improvement in local practice. In the first audit, images were acquired in all the three necessary planes and the sagittal and coronal images had appropriate slice thickness, interslice gap as well as adequate anatomical coverage in all the patients. However, FOV (field of view) was appropriately set in 66% of cases in axial plane, 5% in sagittal plane, and 0% in coronal plane. Also, the anatomical coverage was not upto the mark in axial plane with 13 studies (66%) having adequate superior coverage, and 16 cases (80%) having recommended inferior anatomical coverage. The re audit performed 6 months later showed improvement with 100% compliance to standards. The first audit showed many shortcomings in acquiring of MRI data in patients undergoing knee MRI with FOV requiring a decrease in all planes and anatomical coverage increase in axial plane. These recommendations were made in departmental meetings and re-audit was done after 6 months. This second audit showed 100 % compliance.

Apparent diffusion coefficient of the normal human brain for various experimental conditions

NASA Astrophysics Data System (ADS)

Moraru, Luminita; Dimitrievici, Lucian

2017-01-01

Diffusion-Weighted Magnetic Resonance Imaging (DW-MRI) is being increasingly used to assess both brain tissues and cerebrospinal fluid integrity. In this paper we study inter-site reproducibility of the apparent diffusion coefficient values for the main cerebral tissues such as gray matter, white matter and into cerebrospinal fluid and for three different stacks of slices that were spaced at L = 79.8, 84.9 and 90 mm. We assessed the impact of the attenuation factor and diffusion gradient on the results reproducibility.

[Application of anoptomagnetic probe Gd-DO3A-EA-FITC in imaging and analyzing the brain interstitial space].

PubMed

Li, Y Q; Sheng, Y; Liang, L; Zhao, Y; Li, H Y; Bai, N; Wang, T; Yuan, L; Han, H B

2018-04-18

To investigate the application of the optical magnetic bimodal molecular probe Gd-DO3A-ethylthiouret-fluorescein isothiocyanate (Gd -DO3A-EA-FITC) in brain tissue imaging and brain interstitial space (ISS). In the study, 24 male SD rats were randomly divided into 3 groups, including magnetic probe group (n=6), optical probe group (n=6) and optical magnetic bimodal probe group (n=12), then the optical magnetic bimodal probe group was divided equally into magnetic probe subgroup (n=6) and optical probe subgroup (n=6). Referencing the brain stereotaxic atlas, the coronal globus pallidus as center level, the probes including gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA), fluorescein isothiocyanate (FITC) and Gd-DO3A-EA-FITC of 2 μL (10 mmol/L) were injected into the caudate nucleus respectively, magnetic resonance imaging (MRI) was performed in the magnetic probe group and magnetic probe subgroup to image the dynamic diffusion and distribution of the probes in the brain ISS, a self-developed brain ISS image processing system was used to measure the diffusion coefficient, clearance, volume fraction and half-time in these two groups. Laser scanning confocal microscope (LSCM) was performed in vitro in the optical probe group and optical probe subgroup for fluorescence imaging at the time points 2 hours after the injection of the probe, and the distribution in the oblique sagittal slice was compared with the result of the first two groups. For the magnetic probe group and magnetic probe subgroup, there were the same imaging results between the probes of Gd-DTPA and Gd-DO3A-EA-FITC. The diffusion parameters of Gd-DTPA and Gd-DO3A-EA-FITC were as follows: the average diffusion coefficients [(3.31±0.11)×10 -4 mm 2 /s vs. (3.37±0.15)×10 -4 mm 2 /s, t=0.942, P=0.360], the clearance [(3.04±0.37) mmol/L vs. (2.90±0.51) mmol/L, t=0.640, P=0.531], the volume fractions (17.18%±0.14% vs. 17.31%±0.15%, t=1.961, P=0.068), the half-time [(86.58±3.31) min vs. (84.61±2.38) min, t=1.412, P=0.177], the diffusion areas [(23.25±0.68) mm 2 vs. (22.71±1.00) mm 2 , t=1.100, P=0.297]. The statistical analysis of each brain was made by t test, and the diffusion parameters were not statistically significant. Moreover, for the optical probe group and optical probe subgroup, the diffusion area of Gd-DO3A-EA-FITC [(22.61±1.16) mm 2 ] was slightly larger than that of FITC [(22.10±1.29) mm 2 ], the statistical analysis of each brain was made by t test, and the diffusion parameters were not statistically significant (t=0.713, P=0.492). Gd-DO3A-EA-FITC shows the same imaging results as the traditional GD-DTPA, and it can be used in measuring brain ISS.

Simultaneous Multi-Slice fMRI using Spiral Trajectories

PubMed Central

Zahneisen, Benjamin; Poser, Benedikt A.; Ernst, Thomas; Stenger, V. Andrew

2014-01-01

Parallel imaging methods using multi-coil receiver arrays have been shown to be effective for increasing MRI acquisition speed. However parallel imaging methods for fMRI with 2D sequences show only limited improvements in temporal resolution because of the long echo times needed for BOLD contrast. Recently, Simultaneous Multi-Slice (SMS) imaging techniques have been shown to increase fMRI temporal resolution by factors of four and higher. In SMS fMRI multiple slices can be acquired simultaneously using Echo Planar Imaging (EPI) and the overlapping slices are un-aliased using a parallel imaging reconstruction with multiple receivers. The slice separation can be further improved using the “blipped-CAIPI” EPI sequence that provides a more efficient sampling of the SMS 3D k-space. In this paper a blipped-spiral SMS sequence for ultra-fast fMRI is presented. The blipped-spiral sequence combines the sampling efficiency of spiral trajectories with the SMS encoding concept used in blipped-CAIPI EPI. We show that blipped spiral acquisition can achieve almost whole brain coverage at 3 mm isotropic resolution in 168 ms. It is also demonstrated that the high temporal resolution allows for dynamic BOLD lag time measurement using visual/motor and retinotopic mapping paradigms. The local BOLD lag time within the visual cortex following the retinotopic mapping stimulation of expanding flickering rings is directly measured and easily translated into an eccentricity map of the cortex. PMID:24518259

Protection of Brain Injury by Amniotic Mesenchymal Stromal Cell-Secreted Metabolites.

PubMed

Pischiutta, Francesca; Brunelli, Laura; Romele, Pietro; Silini, Antonietta; Sammali, Eliana; Paracchini, Lara; Marchini, Sergio; Talamini, Laura; Bigini, Paolo; Boncoraglio, Giorgio B; Pastorelli, Roberta; De Simoni, Maria-Grazia; Parolini, Ornella; Zanier, Elisa R

2016-11-01

To define the features of human amniotic mesenchymal stromal cell secretome and its protective properties in experimental models of acute brain injury. Prospective experimental study. Laboratory research. C57Bl/6 mice. Mice subjected to sham or traumatic brain injury by controlled cortical impact received human amniotic mesenchymal stromal cells or phosphate-buffered saline infused intracerebroventricularly or intravenously 24 hours after injury. Organotypic cortical brain slices exposed to ischemic injury by oxygen-glucose deprivation were treated with human amniotic mesenchymal stromal cells or with their secretome (conditioned medium) in a transwell system. Traumatic brain injured mice receiving human amniotic mesenchymal stromal cells intravenously or intracerebroventricularly showed early and lasting functional and anatomical brain protection. cortical slices injured by oxigen-glucose deprivation and treated with human amniotic mesenchymal stromal cells or conditioned medium showed comparable protective effects (neuronal rescue, promotion of M2 microglia polarization, induction of trophic factors) indicating that the exposure of human amniotic mesenchymal stromal cells to the injured tissue is not necessary for the release of bioactive factors. Using sequential size-exclusion and gel-filtration chromatography, we identified a conditioned medium subfraction, which specifically displays these highly protective properties and we found that this fraction was rich in bioactive molecules with molecular weight smaller than 700 Da. Quantitative RNA analysis and mass spectrometry-based peptidomics showed that the active factors are not proteins or RNAs. The metabolomic profiling of six metabolic classes identified a list of molecules whose abundance was selectively elevated in the active conditioned medium fraction. Human amniotic mesenchymal stromal cell-secreted factors protect the brain after acute injury. Importantly, a fraction rich in metabolites, and containing neither proteic nor ribonucleic molecules was protective. This study indicates the profiling of protective factors that could be useful in cell-free therapeutic approaches for acute brain injury.

HttQ111/+ Huntington's Disease Knock-in Mice Exhibit Brain Region-Specific Morphological Changes and Synaptic Dysfunction.

PubMed

Kovalenko, Marina; Milnerwood, Austen; Giordano, James; St Claire, Jason; Guide, Jolene R; Stromberg, Mary; Gillis, Tammy; Sapp, Ellen; DiFiglia, Marian; MacDonald, Marcy E; Carroll, Jeffrey B; Lee, Jong-Min; Tappan, Susan; Raymond, Lynn; Wheeler, Vanessa C

2018-01-01

Successful disease-modifying therapy for Huntington's disease (HD) will require therapeutic intervention early in the pathogenic process. Achieving this goal requires identifying phenotypes that are proximal to the HTT CAG repeat expansion. To use Htt CAG knock-in mice, precise genetic replicas of the HTT mutation in patients, as models to study proximal disease events. Using cohorts of B6J.HttQ111/+ mice from 2 to 18 months of age, we analyzed pathological markers, including immunohistochemistry, brain regional volumes and cortical thickness, CAG instability, electron microscopy of striatal synapses, and acute slice electrophysiology to record glutamatergic transmission at striatal synapses. We also incorporated a diet perturbation paradigm for some of these analyses. B6J.HttQ111/+ mice did not exhibit significant neurodegeneration or gliosis but revealed decreased striatal DARPP-32 as well as subtle but regional-specific changes in brain volumes and cortical thickness that parallel those in HD patients. Ultrastructural analyses of the striatum showed reduced synapse density, increased postsynaptic density thickness and increased synaptic cleft width. Acute slice electrophysiology showed alterations in spontaneous AMPA receptor-mediated postsynaptic currents, evoked NMDA receptor-mediated excitatory postsynaptic currents, and elevated extrasynaptic NMDA currents. Diet influenced cortical thickness, but did not impact somatic CAG expansion, nor did it show any significant interaction with genotype on immunohistochemical, brain volume or cortical thickness measures. These data show that a single HttQ111 allele is sufficient to elicit brain region-specific morphological changes and early neuronal dysfunction, highlighting an insidious disease process already apparent in the first few months of life.

Atypical PKC, PKCλ/ι, activates β-secretase and increases Aβ1-40/42 and phospho-tau in mouse brain and isolated neuronal cells, and may link hyperinsulinemia and other aPKC activators to development of pathological and memory abnormalities in Alzheimer's disease.

PubMed

Sajan, Mini P; Hansen, Barbara C; Higgs, Margaret G; Kahn, C Ron; Braun, Ursula; Leitges, Michael; Park, Collin R; Diamond, David M; Farese, Robert V

2018-01-01

Hyperinsulinemia activates brain Akt and PKC-λ/ι and increases Aβ 1-40/42 and phospho-tau in insulin-resistant animals. Here, we examined underlying mechanisms in mice, neuronal cells, and mouse hippocampal slices. Like Aβ 1-40/42 , β-secretase activity was increased in insulin-resistant mice and monkeys. In insulin-resistant mice, inhibition of hepatic PKC-λ/ι sufficient to correct hepatic abnormalities and hyperinsulinemia simultaneously reversed increases in Akt, atypical protein kinase C (aPKC), β-secretase, and Aβ 1-40/42 , and restored acute Akt activation. However, 2 aPKC inhibitors additionally blocked insulin's ability to activate brain PKC-λ/ι and thereby increase β-secretase and Aβ 1-40/42 . Furthermore, direct blockade of brain aPKC simultaneously corrected an impairment in novel object recognition in high-fat-fed insulin-resistant mice. In neuronal cells and/or mouse hippocampal slices, PKC-ι/λ activation by insulin, metformin, or expression of constitutive PKC-ι provoked increases in β-secretase, Aβ 1-40/42 , and phospho-thr-231-tau that were blocked by various PKC-λ/ι inhibitors, but not by an Akt inhibitor. PKC-λ/ι provokes increases in brain β-secretase, Aβ 1-40/42 , and phospho-thr-231-tau. Excessive signaling via PKC-λ/ι may link hyperinsulinemia and other PKC-λ/ι activators to pathological and functional abnormalities in Alzheimer's disease. Published by Elsevier Inc.

Guanosine-5'-monophosphate induces cell death in rat hippocampal slices via ionotropic glutamate receptors activation and glutamate uptake inhibition.

PubMed

Molz, Simone; Dal-Cim, Tharine; Tasca, Carla I

2009-12-01

Guanine derivatives modulate the glutamatergic system through displacement of binding of glutamate to its receptors acting as antagonist of glutamate receptors in moderate to high micromolar concentrations. Guanosine-5'-monophosphate (GMP) is shown to be neuroprotective against glutamate- or oxygen/glucose deprivation-induced neurotoxicity and also against NMDA-induced apoptosis in hippocampal slices. However, in this study we are showing that high extracellular GMP concentrations (5mM) reduced cell viability in hippocampal brain slices. The toxic effect of GMP was not blocked by dipyridamole, a nucleoside transport inhibitor, nor mimicked by guanosine, suggesting an extracellular mode of action to GMP which does not involve its hydrolysis to guanosine. GMP-dependent cell damage was not blocked by P1 purinergic receptor antagonists, neither altered by adenosine A(1) or A(2A) receptor agonists. The blockage of the ionotropic glutamate receptors AMPA or NMDA, but not KA or metabotropic glutamate receptors, reversed the toxicity induced by GMP. GMP (5mM) induced a decrease in glutamate uptake into hippocampal slices, which was reversed by dl-TBOA. Therefore, GMP-induced hippocampal cell damage involves activation of ionotropic glutamate receptors and inhibition of glutamate transporters activity.

Metabolic Therapy for Temporal Lobe Epilepsy in a Dish: Investigating Mechanisms of Ketogenic Diet using Electrophysiological Recordings in Hippocampal Slices

PubMed Central

Kawamura, Masahito Jr.; Ruskin, David N.; Masino, Susan A.

2016-01-01

The hippocampus is prone to epileptic seizures and is a key brain region and experimental platform for investigating mechanisms associated with the abnormal neuronal excitability that characterizes a seizure. Accordingly, the hippocampal slice is a common in vitro model to study treatments that may prevent or reduce seizure activity. The ketogenic diet is a metabolic therapy used to treat epilepsy in adults and children for nearly 100 years; it can reduce or eliminate even severe or refractory seizures. New insights into its underlying mechanisms have been revealed by diverse types of electrophysiological recordings in hippocampal slices. Here we review these reports and their relevant mechanistic findings. We acknowledge that a major difficulty in using hippocampal slices is the inability to reproduce precisely the in vivo condition of ketogenic diet feeding in any in vitro preparation, and progress has been made in this in vivo/in vitro transition. Thus far at least three different approaches are reported to reproduce relevant diet effects in the hippocampal slices: (1) direct application of ketone bodies; (2) mimicking the ketogenic diet condition during a whole-cell patch-clamp technique; and (3) reduced glucose incubation of hippocampal slices from ketogenic diet–fed animals. Significant results have been found with each of these methods and provide options for further study into short- and long-term mechanisms including Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels, vesicular glutamate transporter (VGLUT), pannexin channels and adenosine receptors underlying ketogenic diet and other forms of metabolic therapy. PMID:27847463

Gain-of-Function Mutations in ZIC1 Are Associated with Coronal Craniosynostosis and Learning Disability.

PubMed

Twigg, Stephen R F; Forecki, Jennifer; Goos, Jacqueline A C; Richardson, Ivy C A; Hoogeboom, A Jeannette M; van den Ouweland, Ans M W; Swagemakers, Sigrid M A; Lequin, Maarten H; Van Antwerp, Daniel; McGowan, Simon J; Westbury, Isabelle; Miller, Kerry A; Wall, Steven A; van der Spek, Peter J; Mathijssen, Irene M J; Pauws, Erwin; Merzdorf, Christa S; Wilkie, Andrew O M

2015-09-03

Human ZIC1 (zinc finger protein of cerebellum 1), one of five homologs of the Drosophila pair-rule gene odd-paired, encodes a transcription factor previously implicated in vertebrate brain development. Heterozygous deletions of ZIC1 and its nearby paralog ZIC4 on chromosome 3q25.1 are associated with Dandy-Walker malformation of the cerebellum, and loss of the orthologous Zic1 gene in the mouse causes cerebellar hypoplasia and vertebral defects. We describe individuals from five families with heterozygous mutations located in the final (third) exon of ZIC1 (encoding four nonsense and one missense change) who have a distinct phenotype in which severe craniosynostosis, specifically involving the coronal sutures, and variable learning disability are the most characteristic features. The location of the nonsense mutations predicts escape of mutant ZIC1 transcripts from nonsense-mediated decay, which was confirmed in a cell line from an affected individual. Both nonsense and missense mutations are associated with altered and/or enhanced expression of a target gene, engrailed-2, in a Xenopus embryo assay. Analysis of mouse embryos revealed a localized domain of Zic1 expression at embryonic days 11.5-12.5 in a region overlapping the supraorbital regulatory center, which patterns the coronal suture. We conclude that the human mutations uncover a previously unsuspected role for Zic1 in early cranial suture development, potentially by regulating engrailed 1, which was previously shown to be critical for positioning of the murine coronal suture. The diagnosis of a ZIC1 mutation has significant implications for prognosis and we recommend genetic testing when common causes of coronal synostosis have been excluded. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Gain-of-Function Mutations in ZIC1 Are Associated with Coronal Craniosynostosis and Learning Disability

PubMed Central

Twigg, Stephen R.F.; Forecki, Jennifer; Goos, Jacqueline A.C.; Richardson, Ivy C.A.; Hoogeboom, A. Jeannette M.; van den Ouweland, Ans M.W.; Swagemakers, Sigrid M.A.; Lequin, Maarten H.; Van Antwerp, Daniel; McGowan, Simon J.; Westbury, Isabelle; Miller, Kerry A.; Wall, Steven A.; van der Spek, Peter J.; Mathijssen, Irene M.J.; Pauws, Erwin; Merzdorf, Christa S.; Wilkie, Andrew O.M.

2015-01-01

Human ZIC1 (zinc finger protein of cerebellum 1), one of five homologs of the Drosophila pair-rule gene odd-paired, encodes a transcription factor previously implicated in vertebrate brain development. Heterozygous deletions of ZIC1 and its nearby paralog ZIC4 on chromosome 3q25.1 are associated with Dandy-Walker malformation of the cerebellum, and loss of the orthologous Zic1 gene in the mouse causes cerebellar hypoplasia and vertebral defects. We describe individuals from five families with heterozygous mutations located in the final (third) exon of ZIC1 (encoding four nonsense and one missense change) who have a distinct phenotype in which severe craniosynostosis, specifically involving the coronal sutures, and variable learning disability are the most characteristic features. The location of the nonsense mutations predicts escape of mutant ZIC1 transcripts from nonsense-mediated decay, which was confirmed in a cell line from an affected individual. Both nonsense and missense mutations are associated with altered and/or enhanced expression of a target gene, engrailed-2, in a Xenopus embryo assay. Analysis of mouse embryos revealed a localized domain of Zic1 expression at embryonic days 11.5–12.5 in a region overlapping the supraorbital regulatory center, which patterns the coronal suture. We conclude that the human mutations uncover a previously unsuspected role for Zic1 in early cranial suture development, potentially by regulating engrailed 1, which was previously shown to be critical for positioning of the murine coronal suture. The diagnosis of a ZIC1 mutation has significant implications for prognosis and we recommend genetic testing when common causes of coronal synostosis have been excluded. PMID:26340333

Retrospective 4D MR image construction from free-breathing slice Acquisitions: A novel graph-based approach.

PubMed

Tong, Yubing; Udupa, Jayaram K; Ciesielski, Krzysztof C; Wu, Caiyun; McDonough, Joseph M; Mong, David A; Campbell, Robert M

2017-01-01

Dynamic or 4D imaging of the thorax has many applications. Both prospective and retrospective respiratory gating and tracking techniques have been developed for 4D imaging via CT and MRI. For pediatric imaging, due to radiation concerns, MRI becomes the de facto modality of choice. In thoracic insufficiency syndrome (TIS), patients often suffer from extreme malformations of the chest wall, diaphragm, and/or spine with inability of the thorax to support normal respiration or lung growth (Campbell et al., 2003, Campbell and Smith, 2007), as such patient cooperation needed by some of the gating and tracking techniques are difficult to realize without causing patient discomfort and interference with the breathing mechanism itself. Therefore (ventilator-supported) free-breathing MRI acquisition is currently the best choice for imaging these patients. This, however, raises a question of how to create a consistent 4D image from such acquisitions. This paper presents a novel graph-based technique for compiling the best 4D image volume representing the thorax over one respiratory cycle from slice images acquired during unencumbered natural tidal-breathing of pediatric TIS patients. In our approach, for each coronal (or sagittal) slice position, images are acquired at a rate of about 200-300ms/slice over several natural breathing cycles which yields over 2000 slices. A weighted graph is formed where each acquired slice constitutes a node and the weight of the arc between two nodes defines the degree of contiguity in space and time of the two slices. For each respiratory phase, an optimal 3D spatial image is constructed by finding the best path in the graph in the spatial direction. The set of all such 3D images for a given respiratory cycle constitutes a 4D image. Subsequently, the best 4D image among all such constructed images is found over all imaged respiratory cycles. Two types of evaluation studies are carried out to understand the behavior of this algorithm and in comparison to a method called Random Stacking - a 4D phantom study and 10 4D MRI acquisitions from TIS patients and normal subjects. The 4D phantom was constructed by 3D printing the pleural spaces of an adult thorax, which were segmented in a breath-held MRI acquisition. Qualitative visual inspection via cine display of the slices in space and time and in 3D rendered form showed smooth variation for all data sets constructed by the proposed method. Quantitative evaluation was carried out to measure spatial and temporal contiguity of the slices via segmented pleural spaces. The optimal method showed smooth variation of the pleural space as compared to Random Stacking whose behavior was erratic. The volumes of the pleural spaces at the respiratory phase corresponding to end inspiration and end expiration were compared to volumes obtained from breath-hold acquisitions at roughly the same phase. The mean difference was found to be roughly 3%. The proposed method is purely image-based and post-hoc and does not need breath holding or external surrogates or instruments to record respiratory motion or tidal volume. This is important and practically warranted for pediatric patients. The constructed 4D images portray spatial and temporal smoothness that should be expected in a consistent 4D volume. We believe that the method can be routinely used for thoracic 4D imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

Autonomic Cholinergic Neurotransmission in the Respiratory System: Effect of Organophosphate Poisoning and Its Treatment

DTIC Science & Technology

1992-05-01

NORWEGIAN: IN ENGLISH: a) Soman Al) Som b) Airways b) Luftveier c) Acetylcholine c) Acetylkolin d) Neuromodulation d Neuromodulering e) Reactivators...and augmented CAMP levels can enhance neurcitransmitter release in brain slices.’-"I Adenosine (ADO) is a neuromodulator both in the Methyixanthines

Electrical stimulation of the insular region attenuates nicotine-taking and nicotine-seeking behaviors.

PubMed

Pushparaj, Abhiram; Hamani, Clement; Yu, Wilson; Shin, Damian S; Kang, Bin; Nobrega, José N; Le Foll, Bernard

2013-03-01

Pharmacological inactivation of the granular insular cortex is able to block nicotine-taking and -seeking behaviors in rats. In this study, we explored the potential of modulating activity in the insular region using electrical stimulation. Animals were trained to self-administer nicotine (0.03 mg/kg per infusion) under a fixed ratio-5 (FR-5) schedule of reinforcement followed by a progressive ratio (PR) schedule. Evaluation of the effect of stimulation in the insular region was performed on nicotine self-administration under FR-5 and PR schedules, as well on reinstatement of nicotine-seeking behavior induced by nicotine-associated cues or nicotine-priming injections. The effect of stimulation was also examined in brain slices containing insular neurons. Stimulation significantly attenuated nicotine-taking, under both schedules of reinforcement, as well as nicotine-seeking behavior induced by cues and priming. These effects appear to be specific to nicotine-associated behaviors, as stimulation did not have any effect on food-taking behavior. They appear to be anatomically specific, as stimulation surrounding the insular region had no effect on behavior. Stimulation of brain slices containing the insular region was found to inactivate insular neurons. Our results suggest that deep brain stimulation to modulate insular activity should be further explored.

Identifying the arterial input function from dynamic contrast-enhanced magnetic resonance images using an apex-seeking technique

NASA Astrophysics Data System (ADS)

Martel, Anne L.

2004-04-01

In order to extract quantitative information from dynamic contrast-enhanced MR images (DCE-MRI) it is usually necessary to identify an arterial input function. This is not a trivial problem if there are no major vessels present in the field of view. Most existing techniques rely on operator intervention or use various curve parameters to identify suitable pixels but these are often specific to the anatomical region or the acquisition method used. They also require the signal from several pixels to be averaged in order to improve the signal to noise ratio, however this introduces errors due to partial volume effects. We have described previously how factor analysis can be used to automatically separate arterial and venous components from DCE-MRI studies of the brain but although that method works well for single slice images through the brain when the blood brain barrier technique is intact, it runs into problems for multi-slice images with more complex dynamics. This paper will describe a factor analysis method that is more robust in such situations and is relatively insensitive to the number of physiological components present in the data set. The technique is very similar to that used to identify spectral end-members from multispectral remote sensing images.

Brain tissue stiffness is a sensitive marker for acidosis.

PubMed

Holtzmann, Kathrin; Gautier, Hélène O B; Christ, Andreas F; Guck, Jochen; Káradóttir, Ragnhildur Thóra; Franze, Kristian

2016-09-15

Carbon dioxide overdose is frequently used to cull rodents for tissue harvesting. However, this treatment may lead to respiratory acidosis, which potentially could change the properties of the investigated tissue. Mechanical tissue properties often change in pathological conditions and may thus offer a sensitive generic readout for changes in biological tissues with clinical relevance. In this study, we performed force-indentation measurements with an atomic force microscope on acute cerebellar slices from adult rats to test if brain tissue undergoes changes following overexposure to CO2 compared to other methods of euthanasia. The pH significantly decreased in brain tissue of animals exposed to CO2. Concomitant with the drop in pH, cerebellar grey matter significantly stiffened. Tissue stiffening was reproduced by incubation of acute cerebellar slices in acidic medium. Tissue stiffness provides an early, generic indicator for pathophysiological changes in the CNS. Atomic force microscopy offers unprecedented high spatial resolution to detect such changes. Our results indicate that the stiffness particularly of grey matter strongly correlates with changes of the pH in the cerebellum. Furthermore, the method of tissue harvesting and preparation may not only change tissue stiffness but very likely also other physiologically relevant parameters, highlighting the importance of appropriate sample preparation. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Optical coherence tomography visualizes neurons in human entorhinal cortex

PubMed Central

Magnain, Caroline; Augustinack, Jean C.; Konukoglu, Ender; Frosch, Matthew P.; Sakadžić, Sava; Varjabedian, Ani; Garcia, Nathalie; Wedeen, Van J.; Boas, David A.; Fischl, Bruce

2015-01-01

Abstract. The cytoarchitecture of the human brain is of great interest in diverse fields: neuroanatomy, neurology, neuroscience, and neuropathology. Traditional histology is a method that has been historically used to assess cell and fiber content in the ex vivo human brain. However, this technique suffers from significant distortions. We used a previously demonstrated optical coherence microscopy technique to image individual neurons in several square millimeters of en-face tissue blocks from layer II of the human entorhinal cortex, over 50  μm in depth. The same slices were then sectioned and stained for Nissl substance. We registered the optical coherence tomography (OCT) images with the corresponding Nissl stained slices using a nonlinear transformation. The neurons were then segmented in both images and we quantified the overlap. We show that OCT images contain information about neurons that is comparable to what can be obtained from Nissl staining, and thus can be used to assess the cytoarchitecture of the ex vivo human brain with minimal distortion. With the future integration of a vibratome into the OCT imaging rig, this technique can be scaled up to obtain undistorted volumetric data of centimeter cube tissue blocks in the near term, and entire human hemispheres in the future. PMID:25741528

Assessing Amide Proton Transfer (APT) MRI Contrast Origins in 9 L Gliosarcoma in the Rat Brain Using Proteomic Analysis.

PubMed

Yan, Kun; Fu, Zongming; Yang, Chen; Zhang, Kai; Jiang, Shanshan; Lee, Dong-Hoon; Heo, Hye-Young; Zhang, Yi; Cole, Robert N; Van Eyk, Jennifer E; Zhou, Jinyuan

2015-08-01

To investigate the biochemical origin of the amide photon transfer (APT)-weighted hyperintensity in brain tumors. Seven 9 L gliosarcoma-bearing rats were imaged at 4.7 T. Tumor and normal brain tissue samples of equal volumes were prepared with a coronal rat brain matrix and a tissue biopsy punch. The total tissue protein and the cytosolic subproteome were extracted from both samples. Protein samples were analyzed using two-dimensional gel electrophoresis, and the proteins with significant abundance changes were identified by mass spectrometry. There was a significant increase in the cytosolic protein concentration in the tumor, compared to normal brain regions, but the total protein concentrations were comparable. The protein profiles of the tumor and normal brain tissue differed significantly. Six cytosolic proteins, four endoplasmic reticulum proteins, and five secreted proteins were considerably upregulated in the tumor. Our experiments confirmed an increase in the cytosolic protein concentration in tumors and identified several key proteins that may cause APT-weighted hyperintensity.

Deep two-photon microscopic imaging through brain tissue using the second singlet state from fluorescent agent chlorophyll α in spinach leaf

NASA Astrophysics Data System (ADS)

Shi, Lingyan; Rodríguez-Contreras, Adrián; Budansky, Yury; Pu, Yang; An Nguyen, Thien; Alfano, Robert R.

2014-06-01

Two-photon (2P) excitation of the second singlet (S) state was studied to achieve deep optical microscopic imaging in brain tissue when both the excitation (800 nm) and emission (685 nm) wavelengths lie in the "tissue optical window" (650 to 950 nm). S2 state technique was used to investigate chlorophyll α (Chl α) fluorescence inside a spinach leaf under a thick layer of freshly sliced rat brain tissue in combination with 2P microscopic imaging. Strong emission at the peak wavelength of 685 nm under the 2P S state of Chl α enabled the imaging depth up to 450 μm through rat brain tissue.

Deep two-photon microscopic imaging through brain tissue using the second singlet state from fluorescent agent chlorophyll α in spinach leaf.

PubMed

Shi, Lingyan; Rodríguez-Contreras, Adrián; Budansky, Yury; Pu, Yang; Nguyen, Thien An; Alfano, Robert R

2014-06-01

Two-photon (2P) excitation of the second singlet (S₂) state was studied to achieve deep optical microscopic imaging in brain tissue when both the excitation (800 nm) and emission (685 nm) wavelengths lie in the "tissue optical window" (650 to 950 nm). S₂ state technique was used to investigate chlorophyll α (Chl α) fluorescence inside a spinach leaf under a thick layer of freshly sliced rat brain tissue in combination with 2P microscopic imaging. Strong emission at the peak wavelength of 685 nm under the 2P S₂ state of Chl α enabled the imaging depth up to 450 μm through rat brain tissue.

Brain anti-cytoxic edema agents.

PubMed

Kimelberg, H K; Barron, K D; Bourke, R S; Nelson, L R; Cragoe, E J

1990-01-01

The work described in this chapter has indicated that improved outcome from an experimental head injury model can be achieved by drugs which are non-diuretic derivatives of loop diuretics, namely indanyl and fluorenyl compounds which are derivatives of ethacrynic acid. These drugs were originally identified by us on the basis of their efficacy in inhibiting [K+]-stimulated, HCO3(-)-dependent swelling of brain cerebrocortical slices. Swelling of glial cells (astrocytes) has long been known to be associated with such slice swelling and astrocyte swelling is a major locus of cytotoxic or cellular brain edema. Qualitative and quantitative electron microscope studies have shown that L644,711, a particularly effective member of the fluorenyl class of drugs, inhibits astrocytic swelling associated with an experimental animal head injury model. We have suggested that astrocytic swelling in pathological states may be partly due to activation of Cl-/HCO3- and Na+/H+ exchange systems driven by increased astrocytic intracellular hydration of CO2, and recent work has indeed shown that the ability of the indanyl and fluorenyl drugs to inhibit brain slice swelling and protect against head injury correlates closely with their ability to inhibit Cl-/HCO3- exchange. All these data suggest that astrocytic swelling, which seems to precede neuronal degeneration and breakdown of the blood-brain barrier, is deleterious and that prevention of such swelling can lead to effective therapy. We have used primary astrocytic cultures to explore reasons why astrocytic swelling could be harmful. Exposing such astrocytes to hypotonic medium causes rapid swelling with a slower return to normal volume in the continued presence of hypotonic medium, a process known as regulatory volume decrease or RVD. Such RVD is associated with marked release of several amino acids, including L-glutamate. L644,711 and other Cl-/HCO3- transport inhibitors such as SITS and furosemide, but not the selective Na+ + K+ + 2Cl- co-transport inhibitor bumetanide, inhibit such swelling-induced release of L-glutamate. Thus, L644,711 and other drugs may be effective in promoting recovery from head injury and other pathological states in which astrocytic swelling occurs either by initially preventing the swelling or inhibiting the release of excitotoxic excitatory amino acids if swelling does occur, perhaps depending at what time the drug is given.

The Organization of the Suprachiasmatic Circadian Pacemaker of the Rat and Its Regulation by Neurotransmitters and Modulators

DTIC Science & Technology

1994-02-02

This clock, located in the brain’s suprachiasmatic nucleus (SCN), can be removed in a slice of hypothalamus, main- tained in a. lite support system...slice of hypothalamus, main- 10> tamned in a lite support system for up to 3 days and studied directly. Using this approach, W.. progress in the 3 112...Wmtz .I’’’f’: A.. wklfIfif cm N.. ffttf:T _ ’I.. ’Af.f-:\\f’:f/. IL & Vrf -:fKE It (IMS31 tff’fa/ifft ’if1\\ lhi/ll ff10 1’’ ) imfii/f’/ftfif/f f/f/ill/i!i

Hippocampal MR volumetry

NASA Astrophysics Data System (ADS)

Haller, John W.; Botteron, K.; Brunsden, Barry S.; Sheline, Yvette I.; Walkup, Ronald K.; Black, Kevin J.; Gado, Mokhtar; Vannier, Michael W.

1994-09-01

Goal: To estimate hippocampal volumes from in vivo 3D magnetic resonance (MR) brain images and determine inter-rater and intra- rater repeatability. Objective: The precision and repeatability of hippocampal volume estimates using stereologic measurement methods is sought. Design: Five normal control and five schizophrenic subjects were MR scanned using a MPRAGE protocol. Fixed grid stereologic methods were used to estimate hippocampal volumes on a graphics workstation. The images were preprocessed using histogram analysis to standardize 3D MR image scaling from 16 to 8 bits and image volumes were interpolated to 0.5 mm3 isotropic voxels. The following variables were constant for the repeated stereologic measures: grid size, inter-slice distance (1.5 mm), voxel dimensions (0.5 mm3), number of hippocampi measured (10), total number of measurements per rater (40), and number of raters (5). Two grid sizes were tested to determine the coefficient of error associated with the number of sampled 'hits' (approximately 140 and 280) on the hippocampus. Starting slice and grid position were randomly varied to assure unbiased volume estimates. Raters were blind to subject identity, diagnosis, and side of the brain from which the image volumes were extracted and the order of subject presentation was randomized for each of the raters. Inter- and intra-rater intraclass correlation coefficients (ICC) were determined. Results: The data indicate excellent repeatability of fixed grid stereologic hippocampal volume measures when using an inter-slice distance of 1.5 mm and a 6.25 mm2 grid (inter-rater ICCs equals 0.86 - 0.97, intra- rater ICCs equals 0.85 - 0.97). One major advantage of the current study was the use of 3D MR data which significantly improved visualization of hippocampal boundaries by providing the ability to access simultaneous orthogonal views while counting stereological marks within the hippocampus. Conclusion: Stereological estimates of 3D volumes from 2D MR sections provide an inexpensive, unbiased and efficient way of determining brain structural volumes. The high precision and repeatability demonstrated with stereological MR volumetry suggest that these methods may be efficiently used to measure small volume reductions associated with schizophrenia and other brain disorders.

Structure-activity relationship of cyanine tau aggregation inhibitors

PubMed Central

Chang, Edward; Congdon, Erin E.; Honson, Nicolette S.; Duff, Karen E.; Kuret, Jeff

2009-01-01

A structure-activity relationship for symmetrical cyanine inhibitors of human tau aggregation was elaborated using a filter trap assay. Antagonist activity depended on cyanine heterocycle, polymethine bridge length, and the nature of meso- and N-substituents. One potent member of the series, 3,3’-diethyl-9-methylthiacarbocyanine iodide (compound 11), retained submicromolar potency and had calculated physical properties consistent with blood-brain barrier and cell membrane penetration. Exposure of organotypic slices prepared from JNPL3 transgenic mice (which express human tau harboring the aggregation prone P301L tauopathy mutation) to compound 11 for one week revealed a biphasic dose response relationship. Low nanomolar concentrations decreased insoluble tau aggregates to half those observed in slices treated with vehicle alone. In contrast, high concentrations (≥300 nM) augmented tau aggregation and produced abnormalities in tissue tubulin levels. These data suggest that certain symmetrical carbocyanine dyes can modulate tau aggregation in the slice biological model at concentrations well below those associated with toxicity. PMID:19432420

Neuronal network imaging in acute slices using Ca2+ sensitive bioluminescent reporter.

PubMed

Tricoire, Ludovic; Lambolez, Bertrand

2014-01-01

Genetically encoded indicators are valuable tools to study intracellular signaling cascades in real time using fluorescent or bioluminescent imaging techniques. Imaging of Ca(2+) indicators is widely used to record transient intracellular Ca(2+) increases associated with bioelectrical activity. The natural bioluminescent Ca(2+) sensor aequorin has been historically the first Ca(2+) indicator used to address biological questions. Aequorin imaging offers several advantages over fluorescent reporters: it is virtually devoid of background signal; it does not require light excitation and interferes little with intracellular processes. Genetically encoded sensors such as aequorin are commonly used in dissociated cultured cells; however it becomes more challenging to express them in differentiated intact specimen such as brain tissue. Here we describe a method to express a GFP-aequorin (GA) fusion protein in pyramidal cells of neocortical acute slices using recombinant Sindbis virus. This technique allows expressing GA in several hundreds of neurons on the same slice and to perform the bioluminescence recording of Ca(2+) transients in single neurons or multiple neurons simultaneously.

Attenuation of hypoxic current by intracellular applications of ATP regenerating agents in hippocampal CA1 neurons of rat brain slices.

PubMed

Chung, I; Zhang, Y; Eubanks, J H; Zhang, L

1998-10-01

Hypoxia-induced outward currents (hyperpolarization) were examined in hippocampal CA1 neurons of rat brain slices, using the whole-cell recording technique. Hypoxic episodes were induced by perfusing slices with an artificial cerebrospinal fluid aerated with 5% CO2/95% N2 rather than 5% CO2/95% O2, for about 3 min. The hypoxic current was consistently and reproducibly induced in CA1 neurons dialysed with an ATP-free patch pipette solution. This current manifested as an outward shift in the holding current in association with increased conductance, and it reversed at -78 +/- 2.5 mV, with a linear I-V relation in the range of -100 to -40 mV. To provide extra energy resources to individual neurons recorded, agents were added to the patch pipette solution, including MgATP alone, MgATP + phosphocreatine + creatine kinase, or MgATP + creatine. In CA1 neurons dialysed with patch solutions including these agents, hypoxia produced small outward currents in comparison with those observed in CA1 neurons dialysed with the ATP-free solution. Among the above agents examined, whole-cell dialysis with MgATP + creatine was the most effective at decreasing the hypoxic outward currents. We suggest that the hypoxic hyperpolarization is closely related to energy metabolism in individual CA1 neurons, and that the energy supply provided by phosphocreatine metabolism may play a critical role during transient metabolic stress.

Regioselective Biolistic Targeting in Organotypic Brain Slices Using a Modified Gene Gun

PubMed Central

Arsenault, Jason; Nagy, Andras; Henderson, Jeffrey T.; O'Brien, John A.

2014-01-01

Transfection of DNA has been invaluable for biological sciences and with recent advances to organotypic brain slice preparations, the effect of various heterologous genes could thus be investigated easily while maintaining many aspects of in vivo biology. There has been increasing interest to transfect terminally differentiated neurons for which conventional transfection methods have been fraught with difficulties such as low yields and significant losses in viability. Biolistic transfection can circumvent many of these difficulties yet only recently has this technique been modified so that it is amenable for use in mammalian tissues. New modifications to the accelerator chamber have enhanced the gene gun's firing accuracy and increased its depths of penetration while also allowing the use of lower gas pressure (50 psi) without loss of transfection efficiency as well as permitting a focused regioselective spread of the particles to within 3 mm. In addition, this technique is straight forward and faster to perform than tedious microinjections. Both transient and stable expression are possible with nanoparticle bombardment where episomal expression can be detected within 24 hr and the cell survival was shown to be better than, or at least equal to, conventional methods. This technique has however one crucial advantage: it permits the transfection to be localized within a single restrained radius thus enabling the user to anatomically isolate the heterologous gene's effects. Here we present an in-depth protocol to prepare viable adult organotypic slices and submit them to regioselective transfection using an improved gene gun. PMID:25407047

Single slice US-MRI registration for neurosurgical MRI-guided US

NASA Astrophysics Data System (ADS)

Pardasani, Utsav; Baxter, John S. H.; Peters, Terry M.; Khan, Ali R.

2016-03-01

Image-based ultrasound to magnetic resonance image (US-MRI) registration can be an invaluable tool in image-guided neuronavigation systems. State-of-the-art commercial and research systems utilize image-based registration to assist in functions such as brain-shift correction, image fusion, and probe calibration. Since traditional US-MRI registration techniques use reconstructed US volumes or a series of tracked US slices, the functionality of this approach can be compromised by the limitations of optical or magnetic tracking systems in the neurosurgical operating room. These drawbacks include ergonomic issues, line-of-sight/magnetic interference, and maintenance of the sterile field. For those seeking a US vendor-agnostic system, these issues are compounded with the challenge of instrumenting the probe without permanent modification and calibrating the probe face to the tracking tool. To address these challenges, this paper explores the feasibility of a real-time US-MRI volume registration in a small virtual craniotomy site using a single slice. We employ the Linear Correlation of Linear Combination (LC2) similarity metric in its patch-based form on data from MNI's Brain Images for Tumour Evaluation (BITE) dataset as a PyCUDA enabled Python module in Slicer. By retaining the original orientation information, we are able to improve on the poses using this approach. To further assist the challenge of US-MRI registration, we also present the BOXLC2 metric which demonstrates a speed improvement to LC2, while retaining a similar accuracy in this context.

Conserved pattern of tangential neuronal migration during forebrain development.

PubMed

Métin, Christine; Alvarez, Chantal; Moudoux, David; Vitalis, Tania; Pieau, Claude; Molnár, Zoltán

2007-08-01

Origin, timing and direction of neuronal migration during brain development determine the distinct organization of adult structures. Changes in these processes might have driven the evolution of the forebrain in vertebrates. GABAergic neurons originate from the ganglionic eminence in mammals and migrate tangentially to the cortex. We are interested in differences and similarities in tangential migration patterns across corresponding telencephalic territories in mammals and reptiles. Using morphological criteria and expression patterns of Darpp-32, Tbr1, Nkx2.1 and Pax6 genes, we show in slice cultures of turtle embryos that early cohorts of tangentially migrating cells are released from the medial ganglionic eminence between stages 14 and 18. Additional populations migrate tangentially from the dorsal subpallium. Large cohorts of tangentially migrating neurons originate ventral to the dorsal ventricular ridge at stage 14 and from the lateral ganglionic eminence from stage 15. Release of GABAergic cells from these regions was investigated further in explant cultures. Tangential migration in turtle proceeds in a fashion similar to mammals. In chimeric slice culture and in ovo graft experiments, the tangentially migrating cells behaved according to the host environment - turtle cells responded to the available cues in mouse slices and mouse cells assumed characteristic migratory routes in turtle brains, indicating highly conserved embryonic signals between these distant species. Our study contributes to the evaluation of theories on the origin of the dorsal cortex and indicates that tangential migration is universal in mammals and sauropsids.

Effect of surface treatments on the bond strength of CAD/CAM fiberglass posts

PubMed Central

Garcia, Paula-Pontes; da Costa, Rogério-Goulart; Garcia, André-Vivan; Gonzaga, Carla-Castiglia; da Cunha, Leonardo-Fernandes; Rezende, Carlos-Eduardo-Edwards

2018-01-01

Background There is no ideal protocol for the surface treatment of fiber posts, especially when using a computer-aided design/computer-aided manufacturing (CAD/CAM) experimental fiberglass block. The purpose of this study was to evaluate the bond strength of a CAD/CAM customized glass fiber post and core after applying different surface treatment techniques. Material and Methods Forty premolars were prepared to receive a customized CAD/CAM glass-fiber post and core obtained from an experimental block of glass fiber and epoxy resin. The specimens were randomly distributed in 4 groups (n=10) according to the post and core surface treatment: ETH - 70% ethanol; HP - 24% hydrogen peroxide for 1 minute; ETH/S - 70% ethanol + silane; HP/S - 24% hydrogen peroxide + silane. The universal adhesive containing silane was applied on the posts and prepared post spaces in all groups. The posts were cemented using dual cure resin cement. The specimens were stored in distilled water at 37°C for 24 h, cut (two slices of 1 mm for each root third - coronal, middle, and apical) and subjected to push-out test (0.5 mm/min). Data was subjected to two-way ANOVA (surface treatment and root third) and Tukey’s test (α=0,05). Results There was no significant difference of bond strength values among groups, regardless the surface treatment (p >0.05). There was significant difference on bond strength values for the different root thirds (p<0.05) (coronal>middle=apical). Conclusions The different surface treatment and application of additional silane in the CAD/CAM customized glass-fiber post and core does not interfere on bond strength values. The root dentin third interfered on the bond strength, with higher values for the coronal third. Key words:Post and core technique, cad/cam, shear strength, hydrogen peroxide. PMID:29930778

A whole brain atlas with sub-parcellation of cortical gyri using resting fMRI

NASA Astrophysics Data System (ADS)

Joshi, Anand A.; Choi, Soyoung; Sonkar, Gaurav; Chong, Minqi; Gonzalez-Martinez, Jorge; Nair, Dileep; Shattuck, David W.; Damasio, Hanna; Leahy, Richard M.

2017-02-01

The new hybrid-BCI-DNI atlas is a high-resolution MPRAGE, single-subject atlas, constructed using both anatomical and functional information to guide the parcellation of the cerebral cortex. Anatomical labeling was performed manually on coronal single-slice images guided by sulcal and gyral landmarks to generate the original (non-hybrid) BCI-DNI atlas. Functional sub-parcellations of the gyral ROIs were then generated from 40 minimally preprocessed resting fMRI datasets from the HCP database. Gyral ROIs were transferred from the BCI-DNI atlas to the 40 subjects using the HCP grayordinate space as a reference. For each subject, each gyral ROI was subdivided using the fMRI data by applying spectral clustering to a similarity matrix computed from the fMRI time-series correlations between each vertex pair. The sub-parcellations were then transferred back to the original cortical mesh to create the subparcellated hBCI-DNI atlas with a total of 67 cortical regions per hemisphere. To assess the stability of the gyral subdivisons, a separate set of 60 HCP datasets were processed as follows: 1) coregistration of the structural scans to the hBCI-DNI atlas; 2) coregistration of the anatomical BCI-DNI atlas without functional subdivisions, followed by sub-parcellation of each subject's resting fMRI data as described above. We then computed consistency between the anatomically-driven delineation of each gyral subdivision and that obtained per subject using individual fMRI data. The gyral sub-parcellations generated by atlas-based registration show variable but generally good overlap of the confidence intervals with the resting fMRI-based subdivisions. These consistency measures will provide a quantitative measure of reliability of each subdivision to users of the atlas.

Regulation of ventral surface chemoreceptors by the central respiratory pattern generator.

PubMed

Guyenet, Patrice G; Mulkey, Daniel K; Stornetta, Ruth L; Bayliss, Douglas A

2005-09-28

The rat retrotrapezoid nucleus (RTN) contains neurons described as central chemoreceptors in the adult and respiratory rhythm-generating pacemakers in neonates [parafacial respiratory group (pfRG)]. Here we test the hypothesis that both RTN and pfRG neurons are intrinsically chemosensitive and tonically firing neurons whose respiratory rhythmicity is caused by a synaptic feedback from the central respiratory pattern generator (CPG). In halothane-anesthetized adults, RTN neurons were silent below 4.5% end-expiratory (e-exp) CO2. Their activity increased linearly (3.2 Hz/1% CO2) up to 6.5% (CPG threshold) and then more slowly to peak approximately 10 Hz at 10% CO2. Respiratory modulation of RTN neurons was absent below CPG threshold, gradually stronger beyond, and, like pfRG neurons, typically (42%) characterized by twin periods of reduced activity near phrenic inspiration. After CPG inactivation with kynurenate (KYN), RTN neurons discharged linearly as a function of e-exp CO2 (slope, +1.7 Hz/1% CO2) and arterial pH (threshold, 7.48; slope, 39 Hz/pH unit). In coronal brain slices (postnatal days 7-12), RTN chemosensitive neurons were silent at pH 7.55. Their activity increased linearly with acidification up to pH 7.2 (17 Hz/pH unit at 35 degrees C) and was always tonic. In conclusion, consistent with their postulated central chemoreceptor role, RTN/pfRG neurons encode pH linearly and discharge tonically when disconnected from the rest of the respiratory centers in vivo (KYN treatment) and in vitro. In vivo, RTN neurons receive respiratory synchronous inhibitory inputs that may serve as feedback and impart these neurons with their characteristic respiratory modulation.

Adenosine A2A receptors modulate the dopamine D2 receptor-mediated inhibition of synaptic transmission in the mouse prefrontal cortex.

PubMed

Real, Joana I; Simões, Ana Patrícia; Cunha, Rodrigo A; Ferreira, Samira G; Rial, Daniel

2018-05-01

Prefrontal cortex (PFC) circuits are modulated by dopamine acting on D 1 - and D 2 -like receptors, which are pharmacologically exploited to manage neuropsychiatric conditions. Adenosine A 2A receptors (A 2 A R) also control PFC-related responses and A 2 A R antagonists are potential anti-psychotic drugs. As tight antagonistic A 2 A R-D 2 R and synergistic A 2 A R-D 1 R interactions occur in other brain regions, we now investigated the crosstalk between A 2 A R and D 1 /D 2 R controlling synaptic transmission between layers II/III and V in mouse PFC coronal slices. Dopamine decreased synaptic transmission, a presynaptic effect based on the parallel increase in paired-pulse responses. Dopamine inhibition was prevented by the D 2 R-like antagonist sulpiride but not by the D 1 R antagonist SCH23390 and was mimicked by the D 2 R agonist sumanirole, but not by the agonists of either D 4 R (A-412997) or D 3 R (PD128907). Dopamine inhibition was prevented by the A 2 A R antagonist, SCH58261, and attenuated in A 2 A R knockout mice. Accordingly, triple-labelling immunocytochemistry experiments revealed the co-localization of A 2 A R and D 2 R immunoreactivity in glutamatergic (vGluT1-positive) nerve terminals of the PFC. This reported positive A 2 A R-D 2 R interaction controlling PFC synaptic transmission provides a mechanistic justification for the anti-psychotic potential of A 2 A R antagonists. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Enhanced taurine release in cell-damaging conditions in the developing and ageing mouse hippocampus.

PubMed

Saransaari, P; Oja, S S

1997-08-01

Taurine has been shown to be essential for neuronal development and survival in the central nervous system. The release of preloaded [3H]taurine was studied in hippocampal slices from seven-day-, three-month- and 18-22-month-old mice in cell-damaging conditions. The slices were superfused in hypoxic, hypoglycemic and ischemic conditions and exposed to free radicals and oxidative stress. The release of taurine was greatly enhanced in the above conditions in all age groups, except in oxidative stress. The release was large in ischemia, particularly in the hippocampus of aged mice. Potassium stimulation was still able to release taurine in cell-damaging conditions in immature mice, whereas in adult and aged animals the release was so substantial that this additional stimulus failed to work. Taurine release was partially Ca2+-dependent in all cases. The massive release of the inhibitory amino acid taurine in ischemic conditions could act neuroprotectively, counteracting in several ways the effects of simultaneous release of excitatory amino acids. This protection could be of great importance in developing brain tissue, while also having an effect in aged brains.

Patch-clamp recordings of rat neurons from acute brain slices of the somatosensory cortex during magnetic stimulation

PubMed Central

Pashut, Tamar; Magidov, Dafna; Ben-Porat, Hana; Wolfus, Shuki; Friedman, Alex; Perel, Eli; Lavidor, Michal; Bar-Gad, Izhar; Yeshurun, Yosef; Korngreen, Alon

2014-01-01

Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. The simulations also predict that neurons with low current threshold are more susceptible to magnetic stimulation. Here we tested these theoretical predictions by combining in vitro patch-clamp recordings from rat brain slices with magnetic stimulation and compartmental modeling. In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field. Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies. PMID:24917788

Hyperforin depletes synaptic vesicles content and induces compartmental redistribution of nerve ending monoamines.

PubMed

Roz, Netta; Rehavi, Moshe

2004-10-22

Hyperforin, a phloroglucinol derivative found in Hypericum perforatum (St. John's wort) extracts has antidepressant properties in depressed patients. Hyperforin has a unique pharmacological profile and it inhibits uptake of biogenic monoamines as well as amino acid transmitters. We have recently showed that the monoamines uptake inhibition exerted by hyperforin is related to its ability to dissipate the pH gradient across the synaptic vesicle membrane thereby interfering with vesicular monoamines storage. In the present study we demonstrate that hyperforin induces dose-dependent efflux of preloaded [3H]5HT and [3H]DA from rat brain slices. Moreover, we show that hyperforin attenuates depolarization- dependent release of monoamines, while increasing monoamine release by amphetamine or fenfluramine. It is also demonstrated that preincubation of brain slices with reserpine is associated with dose- dependent blunting of efflux due to hyperforin. Our data indicate that hyperforin-induced efflux of [3H]5HT and [3H]DA reflect elevated cytoplasmic concentrations of the two monoamines secondary to the depletion of the synaptic vesicle content and the compartmental redistribution of nerve ending monoamines. Copyright 2004 Elsevier Inc.

A fast stimulability screening protocol for neuronal cultures on microelectrode arrays.

PubMed

Kapucu, Fikret E; Tanskanen, Jarno M A; Yuan, Yuting; Hyttinen, Jari A K

2015-01-01

Microelectrode arrays (MEAs) are used to study the electrical activity in brain slices and neuronal cultures. MEA experiments for the analysis of electrical stimulation responses require the tissue or culture to be prone to stimulation. For brain slices, potential stimulation sites may be directly visible in microscope, in which case the determination of stimulability at those locations is sufficient. In unstructured neuronal cultures, potential stimulation sites may not be known a priori, and spatial stimulability screening should be performed. Considering, e.g., 59 microelectrode sites, each to be stimulated several times, may result in long screening times, unacceptable with a MEA system without an integrated CO2 incubator, or in high stimulation effects on the networks. Here, we describe an implementation of a fast stimulation protocol employing pseudorandom stimulation site switching aiming at alleviating the network effects of the stimulability screening. In this paper, we show the usability of the proposed protocol by first detecting stimulable locations and subsequently apply repeated stimulation on the identified potentially stimulable locations to observe an exemplary neuronal pathway.

A microelectrode array electrodeposited with reduced graphene oxide and Pt nanoparticles for norepinephrine and electrophysiological recordings

NASA Astrophysics Data System (ADS)

Wang, Li; Song, Yilin; Zhang, Yu; Xu, Shengwei; Xu, Huiren; Wang, Mixia; Wang, Yang; Cai, Xinxia

2017-11-01

Norepinephrine (NE), a common neurotransmitter released by locus coeruleus neurons, plays an essential role in the communication mechanism of the mammalian nervous system. In this work, a microelectrode array (MEA) was fabricated by micro-electromechanical system (MEMS) technology to provide a rapid, sensitive and reliable method for the direct determination in NE dynamic secretion. To improve the electrical performance, the MEA was electrodeposited with the reduced graphene oxide and Pt nanoparticles (rGOPNps). rGOPNps-MEA was investigated using scanning electron microscopy, atomic force microscopy and electrochemical impedance spectroscopy, differential pulse voltammetry exhibited remarkably electrocatalytic properties towards NE. Calibration results showed a sensitivity of 1.03 nA µM-1 to NE with a detection limit of 0.08 µM. In Particular, the MEA was successfully used for measuring dynamic extracellular NE secretion from the locus coeruleus brain slice, as well as monitoring spike firing from the hippocampal brain slice. This fabricated device has potential in studies of spatially resolved delivery of trace neurochemicals and electrophysiological activities of a variety of biological tissues in vitro.

Essential role of the cAMP-cAMP response-element binding protein pathway in opiate-induced homeostatic adaptations of locus coeruleus neurons.

PubMed

Cao, Jun-Li; Vialou, Vincent F; Lobo, Mary Kay; Robison, Alfred J; Neve, Rachael L; Cooper, Donald C; Nestler, Eric J; Han, Ming-Hu

2010-09-28

Excessive inhibition of brain neurons in primary or slice cultures can induce homeostatic intrinsic plasticity, but the functional role and underlying molecular mechanisms of such plasticity are poorly understood. Here, we developed an ex vivo locus coeruleus (LC) slice culture system and successfully recapitulated the opiate-induced homeostatic adaptation in electrical activity of LC neurons seen in vivo. We investigated the mechanisms underlying this adaptation in LC slice cultures by use of viral-mediated gene transfer and genetic mutant mice. We found that short-term morphine treatment of slice cultures almost completely abolished the firing of LC neurons, whereas chronic morphine treatment increased LC neuronal excitability as revealed during withdrawal. This increased excitability was mediated by direct activation of opioid receptors and up-regulation of the cAMP pathway and accompanied by increased cAMP response-element binding protein (CREB) activity. Overexpression of a dominant negative CREB mutant blocked the increase in LC excitability induced by morphine- or cAMP-pathway activation. Knockdown of CREB in slice cultures from floxed CREB mice similarly decreased LC excitability. Furthermore, the ability of morphine or CREB overexpression to up-regulate LC firing was blocked by knockout of the CREB target adenylyl cyclase 8. Together, these findings provide direct evidence that prolonged exposure to morphine induces homeostatic plasticity intrinsic to LC neurons, involving up-regulation of the cAMP-CREB signaling pathway, which then enhances LC neuronal excitability.

Atorvastatin and Fluoxetine Prevent Oxidative Stress and Mitochondrial Dysfunction Evoked by Glutamate Toxicity in Hippocampal Slices.

PubMed

Ludka, Fabiana K; Dal-Cim, Tharine; Binder, Luisa Bandeira; Constantino, Leandra Celso; Massari, Caio; Tasca, Carla I

2017-07-01

Atorvastatin has been shown to exert a neuroprotective action by counteracting glutamatergic toxicity. Recently, we have shown atorvastatin also exerts an antidepressant-like effect that depends on both glutamatergic and serotonergic systems modulation. Excitotoxicity is involved in several brain disorders including depression; thus, it is suggested that antidepressants may target glutamatergic system as a final common pathway. In this study, a comparison of the mechanisms involved in the putative neuroprotective effect of a repetitive atorvastatin or fluoxetine treatment against glutamate toxicity in hippocampal slices was performed. Adult Swiss mice were treated with atorvastatin (10 mg/kg, p.o.) or fluoxetine (10 mg/kg, p.o.), once a day during seven consecutive days. On the eighth day, animals were killed and hippocampal slices were obtained and subjected to an in vitro protocol of glutamate toxicity. An acute treatment of atorvastatin or fluoxetine was not neuroprotective; however, the repeated atorvastatin or fluoxetine treatment prevented the decrease in cellular viability induced by glutamate in hippocampal slices. The loss of cellular viability induced by glutamate was accompanied by increased D-aspartate release, increased reactive oxygen species (ROS) and nitric oxide (NO) production, and impaired mitochondrial membrane potential. Atorvastatin or fluoxetine repeated treatment also presented an antidepressant-like effect in the tail suspension test. Atorvastatin or fluoxetine treatment was effective in protecting mice hippocampal slices from glutamate toxicity by preventing the oxidative stress and mitochondrial dysfunction.

Spatiotemporal alterations of cortical network activity by selective loss of NOS-expressing interneurons.

PubMed

Shlosberg, Dan; Buskila, Yossi; Abu-Ghanem, Yasmin; Amitai, Yael

2012-01-01

Deciphering the role of GABAergic neurons in large neuronal networks such as the neocortex forms a particularly complex task as they comprise a highly diverse population. The neuronal isoform of the enzyme nitric oxide synthase (nNOS) is expressed in the neocortex by specific subsets of GABAergic neurons. These neurons can be identified in live brain slices by the nitric oxide (NO) fluorescent indicator diaminofluorescein-2 diacetate (DAF-2DA). However, this indicator was found to be highly toxic to the stained neurons. We used this feature to induce acute phototoxic damage to NO-producing neurons in cortical slices, and measured subsequent alterations in parameters of cellular and network activity. Neocortical slices were briefly incubated in DAF-2DA and then illuminated through the 4× objective. Histochemistry for NADPH-diaphorase (NADPH-d), a marker for nNOS activity, revealed elimination of staining in the illuminated areas following treatment. Whole cell recordings from several neuronal types before, during, and after illumination confirmed the selective damage to non-fast-spiking (FS) interneurons. Treated slices displayed mild disinhibition. The reversal potential of compound synaptic events on pyramidal neurons became more positive, and their decay time constant was elongated, substantiating the removal of an inhibitory conductance. The horizontal decay of local field potentials (LFPs) was significantly reduced at distances of 300-400 μm from the stimulation, but not when inhibition was non-selectively weakened with the GABA(A) blocker picrotoxin. Finally, whereas the depression of LFPs along short trains of 40 Hz stimuli was linearly reduced with distance or initial amplitude in control slices, this ordered relationship was disrupted in DAF-treated slices. These results reveal that NO-producing interneurons in the neocortex convey lateral inhibition to neighboring columns, and shape the spatiotemporal dynamics of the network's activity.

Fructose-1,6-Bisphospate does not preserve ATP in hypoxic-ischemic neonatal cerebrocortical slices

PubMed Central

Liu, Jia; Hirai, Kiyoshi; Litt, Lawrence

2008-01-01

Fructose-1,6-bisphosphate (FBP), an endogenous intracellular metabolite in glycolysis, was found in many preclinical studies to be neuroprotective during hypoxia-ischemia (HI) when administered exogenously. We looked for HI neuroprotection from FBP in a neonatal rat brain slice model, using 14.1 Tesla 1H /31P/13C NMR spectroscopy of perchloric acid slice extracts to ask: 1) if FBP preserves high energy phosphates during HI; and 2) if exogenous [1-13C]FBP enters cells and is glycolytically metabolized to [3-13C]lactate. We also asked: 3) if substantial superoxide production occurs during and after HI, thinking such might be treatable by exogenous FBP's antioxidant effects. Superfused P7 rat cerebrocortical slices (350μm) were treated with 2 mM FBP before and during 30 min of HI, and then given four hours of recovery with an FBP-free oxygenated superfusate. Slices were removed before HI, at the end of HI, and at 1 and 4 hours after HI. FBP did not improve high energy phosphate levels or change 1H metabolite profiles. Large increases in [3-13C]lactate were seen with 13C NMR, but the lactate fractional enrichment was always (1.1±0.5)%, implying that all of lactate's 13C was natural abundance 13C, that none was from metabolism of 13C-FBP. FBP had no effect on the fluorescence of ethidium produced from superoxide oxidation of hydroethidine. Compared to control slices, ethidium fluorescence was 25% higher during HI and 50% higher at the end of recovery. Exogenous FBP did not provide protection or enter glycolysis. Its use as an antioxidant might be worth studying at higher FBP concentrations. PMID:18725216

Paclitaxel Causes Electrophysiological Changes in the Anterior Cingulate Cortex via Modulation of the γ-Aminobutyric Acid-ergic System.

PubMed

Nashawi, Houda; Masocha, Willias; Edafiogho, Ivan O; Kombian, Samuel B

The aim of this study was to elucidate any electrophysiological changes that may contribute to the development of neuropathic pain during treatment with the anticancer drug paclitaxel, particularly in the γ-aminobutyric acid (GABA) system. One hundred and eight Sprague-Dawley rats were used (untreated control: 43; vehicle-treated: 21, and paclitaxel-treated: 44). Paclitaxel (8 mg/kg) was administered intraperitoneally on 2 alternate days to induce mechanical allodynia. The rats were sacrificed 7 days after treatment to obtain slices of the anterior cingulate cortex (ACC), a brain region involved in the central processing of pain. Field excitatory postsynaptic potentials (fEPSPs) were recorded in layer II/III of ACC slices, and stimulus-response curves were constructed. The observed effects were pharmacologically characterized by bath application of GABA and appropriate drugs to the slices. The paclitaxel-treated rats developed mechanical allodynia (i.e. reduced withdrawal threshold to mechanical stimuli). Slices from paclitaxel-treated rats produced a significantly higher maximal response (Emax) than those from untreated rats (p < 0.001). Bath application of GABA (0.4 µM) reversed this effect and returned the excitability to a level similar to control. Pretreatment of the slices with the GABAB receptor blocker CGP 55845 (50 µM) increased Emax in slices from untreated rats (p < 0.01) but not from paclitaxel-treated rats. In this study, there was a GABA deficit in paclitaxel-treated rats compared to untreated ones. Such a deficit could contribute to the pathophysiology of paclitaxel-induced neuropathic pain (PINP). Thus, the GABAergic system might be a potential therapeutic target for managing PINP. © 2016 S. Karger AG, Basel.

18F-FDG positron autoradiography with a particle counting silicon pixel detector.

PubMed

Russo, P; Lauria, A; Mettivier, G; Montesi, M C; Marotta, M; Aloj, L; Lastoria, S

2008-11-07

We report on tests of a room-temperature particle counting silicon pixel detector of the Medipix2 series as the detector unit of a positron autoradiography (AR) system, for samples labelled with (18)F-FDG radiopharmaceutical used in PET studies. The silicon detector (1.98 cm(2) sensitive area, 300 microm thick) has high intrinsic resolution (55 microm pitch) and works by counting all hits in a pixel above a certain energy threshold. The present work extends the detector characterization with (18)F-FDG of a previous paper. We analysed the system's linearity, dynamic range, sensitivity, background count rate, noise, and its imaging performance on biological samples. Tests have been performed in the laboratory with (18)F-FDG drops (37-37 000 Bq initial activity) and ex vivo in a rat injected with 88.8 MBq of (18)F-FDG. Particles interacting in the detector volume produced a hit in a cluster of pixels whose mean size was 4.3 pixels/event at 11 keV threshold and 2.2 pixels/event at 37 keV threshold. Results show a sensitivity for beta(+) of 0.377 cps Bq(-1), a dynamic range of at least five orders of magnitude and a lower detection limit of 0.0015 Bq mm(-2). Real-time (18)F-FDG positron AR images have been obtained in 500-1000 s exposure time of thin (10-20 microm) slices of a rat brain and compared with 20 h film autoradiography of adjacent slices. The analysis of the image contrast and signal-to-noise ratio in a rat brain slice indicated that Poisson noise-limited imaging can be approached in short (e.g. 100 s) exposures, with approximately 100 Bq slice activity, and that the silicon pixel detector produced a higher image quality than film-based AR.

Childhood and adolescent obesity and long-term cognitive consequences during aging.

PubMed

Wang, Jun; Freire, Daniel; Knable, Lindsay; Zhao, Wei; Gong, Bing; Mazzola, Paolo; Ho, Lap; Levine, Samara; Pasinetti, Giulio M

2015-04-01

The prevalence of childhood/adolescent obesity and insulin resistance has reached an epidemic level. Obesity's immediate clinical impacts have been extensively studied; however, current clinical evidence underscores the long-term implications. The current study explored the impacts of brief childhood/adolescent obesity and insulin resistance on cognitive function in later life. To mimic childhood/adolescent obesity and insulin resistance, we exposed 9-week-old C57BL/6J mice to a high-fat diet for 15 weeks, after which the mice exhibited diet-induced obesity and insulin resistance. We then put these mice back on a normal low-fat diet, after which the mice exhibited normal body weight and glucose tolerance. However, a spatial memory test in the forms of the Morris water maze (MWM) and contextual fear conditioning at 85 weeks of age showed that these mice had severe deficits in learning and long-term memory consolidation. Mechanistic investigations identified increased expression of histone deacetylases 5, accompanied by reduced expression of brain-derived neurotrophic factor, in the brains 61 weeks after the mice had been off the high-fat diet. Electrophysiology studies showed that hippocampal slices isolated from these mice are more susceptible to synaptic impairments compared with slices isolated from the control mice. We demonstrated that a 15-week occurrence of obesity and insulin resistance during childhood/adolescence induces irreversible epigenetic modifications in the brain that persist following restoration of normal metabolic homeostasis, leading to brain synaptic dysfunction during aging. Our study provides experimental evidence that limited early-life exposure to obesity and insulin resistance may have long-term deleterious consequences in the brain, contributing to the onset/progression of cognitive dysfunction during aging. © 2014 Wiley Periodicals, Inc.

HttQ111/+ Huntington’s Disease Knock-in Mice Exhibit Brain Region-Specific Morphological Changes and Synaptic Dysfunction

PubMed Central

Kovalenko, Marina; Milnerwood, Austen; Giordano, James; St. Claire, Jason; Guide, Jolene R.; Stromberg, Mary; Gillis, Tammy; Sapp, Ellen; DiFiglia, Marian; MacDonald, Marcy E.; Carroll, Jeffrey B.; Lee, Jong-Min; Tappan, Susan; Raymond, Lynn; Wheeler, Vanessa C.

2018-01-01

Background: Successful disease-modifying therapy for Huntington’s disease (HD) will require therapeutic intervention early in the pathogenic process. Achieving this goal requires identifying phenotypes that are proximal to the HTT CAG repeat expansion. Objective: To use Htt CAG knock-in mice, precise genetic replicas of the HTT mutation in patients, as models to study proximal disease events. Methods: Using cohorts of B6J.HttQ111/+ mice from 2 to 18 months of age, we analyzed pathological markers, including immunohistochemistry, brain regional volumes and cortical thickness, CAG instability, electron microscopy of striatal synapses, and acute slice electrophysiology to record glutamatergic transmission at striatal synapses. We also incorporated a diet perturbation paradigm for some of these analyses. Results: B6J.HttQ111/+ mice did not exhibit significant neurodegeneration or gliosis but revealed decreased striatal DARPP-32 as well as subtle but regional-specific changes in brain volumes and cortical thickness that parallel those in HD patients. Ultrastructural analyses of the striatum showed reduced synapse density, increased postsynaptic density thickness and increased synaptic cleft width. Acute slice electrophysiology showed alterations in spontaneous AMPA receptor-mediated postsynaptic currents, evoked NMDA receptor-mediated excitatory postsynaptic currents, and elevated extrasynaptic NMDA currents. Diet influenced cortical thickness, but did not impact somatic CAG expansion, nor did it show any significant interaction with genotype on immunohistochemical, brain volume or cortical thickness measures. Conclusions: These data show that a single HttQ111 allele is sufficient to elicit brain region-specific morphological changes and early neuronal dysfunction, highlighting an insidious disease process already apparent in the first few months of life. PMID:29480209

Targeting the Dopamine 1 Receptor or its Downstream Signalling by Inhibiting Phosphodiesterase-1 Improves Cognitive Performance.

PubMed

Pekcec, Anton; Schülert, Niklas; Stierstorfer, Birgit; Deiana, Serena; Dorner-Ciossek, Cornelia; Rosenbrock, Holger

2018-05-03

Insufficient prefrontal dopamine 1 (D1) receptor signalling has been linked to cognitive dysfunction in several psychiatric conditions. Because the phosphodiesterase-1 (PDE1) isoform B (PDE1B) is postulated to regulate D1 receptor-dependent signal transduction, this study intended to elucidate the role of PDE1 for cognitive processes reliant on D1 receptor function. Cognitive performance of the D1 receptor agonist, SKF38393, was studied in the T-maze continuous alternation task and the 5-Choice Serial Reaction Time Task. D1 receptor/ PDE1B double-immunohistochemistry was performed using human and rat prefrontal brain sections. Pharmacological activity of the PDE1 inhibitor, ITI-214, was assessed by measuring the increase of cAMP/ cGMP in prefrontal brain tissue and its effect on working memory performance. Mechanistic studies on modulation of prefrontal neuronal transmission by SKF38393 and ITI-214 were performed using extracellular recordings in brain slices. SKF38393 improved working memory and attentional performance in rodents. D1 receptor/ PDE1B co-expression was verified in both, human and rat prefrontal brain sections. The pharmacological activity of ITI-214 on its target was demonstrated by increased prefrontal cAMP/ cGMP upon administration. In addition, ITI-214 improved working memory performance. SKF38393 and ITI-214 facilitated neuronal transmission in prefrontal brain slices. We hypothesise that PDE1 inhibition may improve working memory performance by increasing prefrontal synaptic transmission and/or postsynaptic D1 receptor signalling, by modulating prefrontal downstream second messenger levels. These data may therefore support the use of PDE1 inhibitors as a potential approach for the treatment of cognitive dysfunction. This article is protected by copyright. All rights reserved.

MALDI Imaging Analysis of Neuropeptides in Africanized Honeybee (Apis mellifera) Brain: Effect of Aggressiveness.

PubMed

Pratavieira, Marcel; Menegasso, Anally Ribeiro da Silva; Esteves, Franciele Grego; Sato, Kenny Umino; Malaspina, Osmar; Palma, Mario Sérgio

2018-05-18

The aggressiveness in honeybees seems to be regulated by multiple genes, under the influence of different factors, such as polyethism of workers, environmental factors, and response to alarm pheromones, creating a series of behavioral responses. It is suspected that neuropeptides seem to be involved with the regulation of the aggressive behavior. The role of allatostatin and tachykinin-related neuropeptides in honeybee brain during the aggressive behavior is unknown; thus, worker honeybees were stimulated to attack and to sting leather targets hanged in front of the colonies. The aggressive individuals were collected and immediately frozen in liquid nitrogen; the heads were removed, and sliced at sagittal plan. The brain slices were submitted to MALDI-Spectral-Imaging analysis, and the results of the present study reported the processing of the precursors proteins into mature forms of the neuropeptides AmAST A (59-76) (AYTYVSEYKRLPVYNFGL-NH2), AmAST A (69-76) (LPVYNFGL-NH2), AmTRP (88 - 96) (APMGFQGMR-NH2), and AmTRP (254 - 262) (ARMGFHGMR-NH2), which apparently acted in different neuropils of honeybee brain, during the aggressive behavior, possibly playing the neuromodulation of different aspects of this complex behavior. These results were biologically validated performing aggressiveness-related behavioral assays, using young honeybee workers that received 1 ng of AmAST A (69-76) or AmTRP (88 - 96) via hemocele. The young workers that were not expected to be aggressive individuals, presented a complete series of the aggressive behaviors, in presence of the neuropeptides, corroborating the hypothesis that correlates the presence of mature AmASTs A and AmTRPs in honeybee brain with the aggressiveness of this insect.

Hyaluronan Deficiency Due to Has3 Knock-Out Causes Altered Neuronal Activity and Seizures via Reduction in Brain Extracellular Space

PubMed Central

Arranz, Amaia M.; Perkins, Katherine L.; Irie, Fumitoshi; Lewis, David P.; Hrabe, Jan; Xiao, Fanrong; Itano, Naoki; Kimata, Koji

2014-01-01

Hyaluronan (HA), a large anionic polysaccharide (glycosaminoglycan), is a major constituent of the extracellular matrix of the adult brain. To address its function, we examined the neurophysiology of knock-out mice deficient in hyaluronan synthase (Has) genes. Here we report that these Has mutant mice are prone to epileptic seizures, and that in Has3−/− mice, this phenotype is likely derived from a reduction in the size of the brain extracellular space (ECS). Among the three Has knock-out models, namely Has3−/−, Has1−/−, and Has2CKO, the seizures were most prevalent in Has3−/− mice, which also showed the greatest HA reduction in the hippocampus. Electrophysiology in Has3−/− brain slices demonstrated spontaneous epileptiform activity in CA1 pyramidal neurons, while histological analysis revealed an increase in cell packing in the CA1 stratum pyramidale. Imaging of the diffusion of a fluorescent marker revealed that the transit of molecules through the ECS of this layer was reduced. Quantitative analysis of ECS by the real-time iontophoretic method demonstrated that ECS volume was selectively reduced in the stratum pyramidale by ∼40% in Has3−/− mice. Finally, osmotic manipulation experiments in brain slices from Has3−/− and wild-type mice provided evidence for a causal link between ECS volume and epileptiform activity. Our results provide the first direct evidence for the physiological role of HA in the regulation of ECS volume, and suggest that HA-based preservation of ECS volume may offer a novel avenue for development of antiepileptogenic treatments. PMID:24790187

[MR myelography: analysis of 126 cases].

PubMed

Wang, W; Zhang, X; Lu, Y

2000-03-01

To investigate the value and limitation of MR myelography (MRM) in depicting the spinal canal obstruction. Heavily T2-weighted coronal MR myelography was performed with 3D fast-spin-echo (FSE) and fat-suppression sequence in 126 cases, including 6 cerebellomedullary cistern, 18 cervical, 19 thoracic and 83 lumbar cases. The resulting slice were then projected into a composite image using a standard maxium intensity projection (MIP) algorithm. 90.5% (114/126) of MRM yielded reproducible high-quality image of the spinal thecal sac. 106 lesions (extradural, intradural, intramedullary) were detected in 101 cases (80.2%). The level and degree of spinal canal obstruction were visualized and confirmed by operation in 66 cases with a high sensitivity of 100%, and a diagnostic accuracy of 91.3%. Heavily T2 FSE MR myelography is a noninvasive and reliable method. MRM surpasses conventional and CT myelography and could replace them in some degree.

Classification of the maxillary sinus according to area of the medial antral wall: a comparison of two ethnic groups.

PubMed

Lee, Fernandes Carmen; Fernandes, C M C; Murrell, H C

2009-06-01

This study is an anatomical study designed to benefit surgeons working in the region of the maxillary sinus. This paper investigates ethnic and gender variations in the shape of the maxillary sinus in dried crania from the Raymond Dart collection of human skeletons. The paper claims that an estimate of the area of the medial antral wall of the maxillary sinus is one of the best ethnic/gender group predictors. Helical, multislice computed tomography was performed using 1mm coronal slices length, depth, width and volume measurements for each sinus were taken. Classification by shape and estimated area of medial wall was attempted. Shape classification was found to be unsuccessful whilst medial wall classification into ethnic/gender groupings gave encouraging results. The area of the medial wall is related to ethnic/gender groups.

A special form of cerebral lacunae: expanding lacunae.

PubMed Central

Homeyer, P; Cornu, P; Lacomblez, L; Chiras, J; Derouesné, C

1996-01-01

The case of a 42 year old man with headache, blurred vision, and diplopia allowed the description of a particular form of cerebral lacunae-that is, expanding lacunae. Brain MRI showed hydrocephalus and multiple lesions in the thalamomesencephalic region. The radiological features of these lesions were similar to the histological brain coronal section of a case reported in 1983 in which expanding lacunae were related to a dilatation of the perivascular spaces and a focal segmental necrotising angiitis. The role of the lymphatic drainage of the brain is discussed to explain the dilatation of the perivascular spaces. The hypothesis of a hydrodynamic factor being responsible for the expanding character of the lacunae was suggested by the location of the lesions and the influence of various clinical events on the symptomatology. Images PMID:8708692

Clostridium perfringens epsilon toxin targets granule cells in the mouse cerebellum and stimulates glutamate release.

PubMed

Lonchamp, Etienne; Dupont, Jean-Luc; Wioland, Laetitia; Courjaret, Raphaël; Mbebi-Liegeois, Corinne; Jover, Emmanuel; Doussau, Frédéric; Popoff, Michel R; Bossu, Jean-Louis; de Barry, Jean; Poulain, Bernard

2010-09-30

Epsilon toxin (ET) produced by C. perfringens types B and D is a highly potent pore-forming toxin. ET-intoxicated animals express severe neurological disorders that are thought to result from the formation of vasogenic brain edemas and indirect neuronal excitotoxicity. The cerebellum is a predilection site for ET damage. ET has been proposed to bind to glial cells such as astrocytes and oligodendrocytes. However, the possibility that ET binds and attacks the neurons remains an open question. Using specific anti-ET mouse polyclonal antibodies and mouse brain slices preincubated with ET, we found that several brain structures were labeled, the cerebellum being a prominent one. In cerebellar slices, we analyzed the co-staining of ET with specific cell markers, and found that ET binds to the cell body of granule cells, oligodendrocytes, but not astrocytes or nerve endings. Identification of granule cells as neuronal ET targets was confirmed by the observation that ET induced intracellular Ca(2+) rises and glutamate release in primary cultures of granule cells. In cultured cerebellar slices, whole cell patch-clamp recordings of synaptic currents in Purkinje cells revealed that ET greatly stimulates both spontaneous excitatory and inhibitory activities. However, pharmacological dissection of these effects indicated that they were only a result of an increased granule cell firing activity and did not involve a direct action of the toxin on glutamatergic nerve terminals or inhibitory interneurons. Patch-clamp recordings of granule cell somata showed that ET causes a decrease in neuronal membrane resistance associated with pore-opening and depolarization of the neuronal membrane, which subsequently lead to the firing of the neuronal network and stimulation of glutamate release. This work demonstrates that a subset of neurons can be directly targeted by ET, suggesting that part of ET-induced neuronal damage observed in neuronal tissue is due to a direct effect of ET on neurons.

Clostridium perfringens Epsilon Toxin Targets Granule Cells in the Mouse Cerebellum and Stimulates Glutamate Release

PubMed Central

Lonchamp, Etienne; Dupont, Jean-Luc; Wioland, Laetitia; Courjaret, Raphaël; Mbebi-Liegeois, Corinne; Jover, Emmanuel; Doussau, Frédéric; Popoff, Michel R.; Bossu, Jean-Louis; de Barry, Jean; Poulain, Bernard

2010-01-01

Epsilon toxin (ET) produced by C. perfringens types B and D is a highly potent pore-forming toxin. ET-intoxicated animals express severe neurological disorders that are thought to result from the formation of vasogenic brain edemas and indirect neuronal excitotoxicity. The cerebellum is a predilection site for ET damage. ET has been proposed to bind to glial cells such as astrocytes and oligodendrocytes. However, the possibility that ET binds and attacks the neurons remains an open question. Using specific anti-ET mouse polyclonal antibodies and mouse brain slices preincubated with ET, we found that several brain structures were labeled, the cerebellum being a prominent one. In cerebellar slices, we analyzed the co-staining of ET with specific cell markers, and found that ET binds to the cell body of granule cells, oligodendrocytes, but not astrocytes or nerve endings. Identification of granule cells as neuronal ET targets was confirmed by the observation that ET induced intracellular Ca2+ rises and glutamate release in primary cultures of granule cells. In cultured cerebellar slices, whole cell patch-clamp recordings of synaptic currents in Purkinje cells revealed that ET greatly stimulates both spontaneous excitatory and inhibitory activities. However, pharmacological dissection of these effects indicated that they were only a result of an increased granule cell firing activity and did not involve a direct action of the toxin on glutamatergic nerve terminals or inhibitory interneurons. Patch-clamp recordings of granule cell somata showed that ET causes a decrease in neuronal membrane resistance associated with pore-opening and depolarization of the neuronal membrane, which subsequently lead to the firing of the neuronal network and stimulation of glutamate release. This work demonstrates that a subset of neurons can be directly targeted by ET, suggesting that part of ET-induced neuronal damage observed in neuronal tissue is due to a direct effect of ET on neurons. PMID:20941361

Dynamic behaviors of growth cones extending in the corpus callosum of living cortical brain slices observed with video microscopy.

PubMed

Halloran, M C; Kalil, K

1994-04-01

During development, axons of the mammalian corpus callosum must navigate across the midline to establish connections with corresponding targets in the contralateral cerebral cortex. To gain insight into how growth cones of callosal axons respond to putative guidance cues along this CNS pathway, we have used time-lapse video microscopy to observe dynamic behaviors of individual callosal growth cones extending in living brain slices from neonatal hamster sensorimotor cortex. Crystals of the lipophilic dye 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil) were inserted into the cortex in vivo to label small populations of callosal axons and their growth cones. Subsequently, 400 microns brain slices that included the injection site, the corpus callosum, and the target cortex were placed in culture and viewed under low-light-level conditions with a silicon-intensified target (SIT) camera. Time-lapse video observations revealed striking differences in growth cone behaviors in different regions of the callosal pathway. In the tract, which is defined as the region of the callosal pathway from the injection site to the corresponding target cortex, growth cones advanced rapidly, displaying continual lamellipodial shape changes and filopodial exploration. Forward advance was sometimes interrupted by brief pauses or retraction. Growth cones in the target cortex had almost uniform compact shapes that were consistently smaller than those in the tract. In cortex, axons adhered to straight radial trajectories and their growth cones extended at only half the speed of those in the tract. Growth cones in subtarget regions of the callosum beneath cortical targets displayed complex behaviors characterized by long pauses, extension of transitory branches, and repeated cycles of collapse, withdrawal, and resurgence. Video observations suggested that extension of axons into cortical targets could occur by interstitial branching from callosal axons rather than by turning behaviors of the primary growth cones. These results suggest the existence of guidance cues distinct for each of these callosal regions that elicit characteristic growth cone behaviors.

Conversion of Synthetic Aβ to In Vivo Active Seeds and Amyloid Plaque Formation in a Hippocampal Slice Culture Model.

PubMed

Novotny, Renata; Langer, Franziska; Mahler, Jasmin; Skodras, Angelos; Vlachos, Andreas; Wegenast-Braun, Bettina M; Kaeser, Stephan A; Neher, Jonas J; Eisele, Yvonne S; Pietrowski, Marie J; Nilsson, K Peter R; Deller, Thomas; Staufenbiel, Matthias; Heimrich, Bernd; Jucker, Mathias

2016-05-04

The aggregation of amyloid-β peptide (Aβ) in brain is an early event and hallmark of Alzheimer's disease (AD). We combined the advantages of in vitro and in vivo approaches to study cerebral β-amyloidosis by establishing a long-term hippocampal slice culture (HSC) model. While no Aβ deposition was noted in untreated HSCs of postnatal Aβ precursor protein transgenic (APP tg) mice, Aβ deposition emerged in HSCs when cultures were treated once with brain extract from aged APP tg mice and the culture medium was continuously supplemented with synthetic Aβ. Seeded Aβ deposition was also observed under the same conditions in HSCs derived from wild-type or App-null mice but in no comparable way when HSCs were fixed before cultivation. Both the nature of the brain extract and the synthetic Aβ species determined the conformational characteristics of HSC Aβ deposition. HSC Aβ deposits induced a microglia response, spine loss, and neuritic dystrophy but no obvious neuron loss. Remarkably, in contrast to in vitro aggregated synthetic Aβ, homogenates of Aβ deposits containing HSCs induced cerebral β-amyloidosis upon intracerebral inoculation into young APP tg mice. Our results demonstrate that a living cellular environment promotes the seeded conversion of synthetic Aβ into a potent in vivo seeding-active form. In this study, we report the seeded induction of Aβ aggregation and deposition in long-term hippocampal slice cultures. Remarkably, we find that the biological activities of the largely synthetic Aβ aggregates in the culture are very similar to those observed in vivo This observation is the first to show that potent in vivo seeding-active Aβ aggregates can be obtained by seeded conversion of synthetic Aβ in a living (wild-type) cellular environment. Copyright © 2016 the authors 0270-6474/16/365084-10$15.00/0.

Imaging neuronal responses in slice preparations of vomeronasal organ expressing a genetically encoded calcium sensor.

PubMed

Ma, Limei; Haga-Yamanaka, Sachiko; Yu, Qingfeng Elden; Qiu, Qiang; Kim, Sangseong; Yu, C Ron

2011-12-06

The vomeronasal organ (VNO) detects chemosensory signals that carry information about the social, sexual and reproductive status of the individuals within the same species. These intraspecies signals, the pheromones, as well as signals from some predators, activate the vomeronasal sensory neurons (VSNs) with high levels of specificity and sensitivity. At least three distinct families of G-protein coupled receptors, V1R, V2R and FPR, are expressed in VNO neurons to mediate the detection of the chemosensory cues. To understand how pheromone information is encoded by the VNO, it is critical to analyze the response profiles of individual VSNs to various stimuli and identify the specific receptors that mediate these responses. The neuroepithelia of VNO are enclosed in a pair of vomer bones. The semi-blind tubular structure of VNO has one open end (the vomeronasal duct) connecting to the nasal cavity. VSNs extend their dendrites to the lumen part of the VNO, where the pheromone cues are in contact with the receptors expressed at the dendritic knobs. The cell bodies of the VSNs form pseudo-stratified layers with V1R and V2R expressed in the apical and basal layers respectively. Several techniques have been utilized to monitor responses of VSNs to sensory stimuli. Among these techniques, acute slice preparation offers several advantages. First, compared to dissociated VSNs, slice preparations maintain the neurons in their native morphology and the dendrites of the cells stay relatively intact. Second, the cell bodies of the VSNs are easily accessible in coronal slice of the VNO to allow electrophysiology studies and imaging experiments as compared to whole epithelium and whole-mount preparations. Third, this method can be combined with molecular cloning techniques to allow receptor identification. Sensory stimulation elicits strong Ca2+ influx in VSNs that is indicative of receptor activation. We thus develop transgenic mice that express G-CaMP2 in the olfactory sensory neurons, including the VSNs. The sensitivity and the genetic nature of the probe greatly facilitate Ca2+ imaging experiments. This method has eliminated the dye loading process used in previous studies. We also employ a ligand delivery system that enables application of various stimuli to the VNO slices. The combination of the two techniques allows us to monitor multiple neurons simultaneously in response to large numbers of stimuli. Finally, we have established a semi-automated analysis pipeline to assist image processing.

Differential calcium dependence in basal and forskolin-potentiated spontaneous transmitter release in basolateral amygdala neurons.

PubMed

Miura, Yuki; Naka, Masamitsu; Matsuki, Norio; Nomura, Hiroshi

2012-10-31

Action potential-independent transmitter release, or spontaneous release, is postulated to produce multiple postsynaptic effects (e.g., maintenance of dendritic spines and suppression of local dendritic protein synthesis). Potentiation of spontaneous release may contribute to the precise modulation of synaptic function. However, the expression mechanism underlying potentiated spontaneous release remains unclear. In this study, we investigated the involvement of extracellular and intracellular calcium in basal and potentiated spontaneous release. Miniature excitatory postsynaptic currents (mEPSCs) of the basolateral amygdala neurons in acute brain slices were recorded. Forskolin, an adenylate cyclase activator, increased mEPSC frequency, and the increase lasted at least 25 min after washout. Removal of the extracellular calcium decreased mEPSC frequency in both naïve and forskolin-treated slices. On the other hand, chelation of intracellular calcium by BAPTA-AM decreased mEPSC frequency in naïve, but not in forskolin-treated slices. A blockade of the calcium-sensing receptor (CaSR) resulted in an increase in mEPSC frequency in forskolin-treated, but not in naïve slices. These findings indicate that forskolin-induced potentiation is accompanied by changes in the mechanisms underlying Ca(2+)-dependent spontaneous release. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Changes in brain cell shape create residual extracellular space volume and explain tortuosity behavior during osmotic challenge.

PubMed

Chen, K C; Nicholson, C

2000-07-18

Diffusion of molecules in brain extracellular space is constrained by two macroscopic parameters, tortuosity factor lambda and volume fraction alpha. Recent studies in brain slices show that when osmolarity is reduced, lambda increases while alpha decreases. In contrast, with increased osmolarity, alpha increases, but lambda attains a plateau. Using homogenization theory and a variety of lattice models, we found that the plateau behavior of lambda can be explained if the shape of brain cells changes nonuniformly during the shrinking or swelling induced by osmotic challenge. The nonuniform cellular shrinkage creates residual extracellular space that temporarily traps diffusing molecules, thus impeding the macroscopic diffusion. The paper also discusses the definition of tortuosity and its independence of the measurement frame of reference.

Criticality in Neuronal Networks

NASA Astrophysics Data System (ADS)

Friedman, Nir; Ito, Shinya; Brinkman, Braden A. W.; Shimono, Masanori; Deville, R. E. Lee; Beggs, John M.; Dahmen, Karin A.; Butler, Tom C.

2012-02-01

In recent years, experiments detecting the electrical firing patterns in slices of in vitro brain tissue have been analyzed to suggest the presence of scale invariance and possibly criticality in the brain. Much of the work done however has been limited in two ways: 1) the data collected is from local field potentials that do not represent the firing of individual neurons; 2) the analysis has been primarily limited to histograms. In our work we examine data based on the firing of individual neurons (spike data), and greatly extend the analysis by considering shape collapse and exponents. Our results strongly suggest that the brain operates near a tuned critical point of a highly distinctive universality class.

[Single shot fast spin echo sequence MRI cholangiopancreatography].

PubMed

Lefèvre, F; Crouzet, P; Gaucher, H; Chapuis, F; Béot, S; Boccaccini, H; Bazin, C; Régent, D

1998-05-01

To assess the value of single shot fast spin echo MR sequence (SS-FSE) in the morphological analysis of the biliary tree and pancreatic ducts and to compare its accuracy with other imaging methods. 95 consecutive patients referred for clinical and/or biological suspicion of biliary obstruction were explored with MR cholangiopancreatography (MRCP). All patients were explored with a Signa 1.5 T GE MR unit, with High Gradient Field Strength and Torso Phased Array Coil. Biliary ducts were explored with SS-FSE sequence, coronal and oblique coronal 20 mm thick slices on a 256 x 256 matrix. Total acquisition time was 1 second. Native pictures were reviewed by two radiologists blinded to clinical information. In case of disagreement, a third radiologist's judgement was requested. In 88 cases, MRCP results were compared with direct biligraphy methods. In all cases, MRCP produced high quality images without MIP or other post-processing methods. For detection of biliary tree distensions, the concordance value of MRCP was over 91% (Kappa 0.82). For detection of biliary tree and/or pancreatic duct obstruction, MR sensitivity was 100% and specificity 91%. The overall diagnostic concordance value of MRCP was > or = 93%. Difficulties in MRCP were caused by functional diseases or benign stenosis. MRCP accurately diagnosed all lithiasic obstructions starting from a stone size of 3 mm. MRCP produces fastly high-quality images. As it is totally safe, it can be proposed as a first intention method in biliopancreatic duct explorations.

Parallel and patterned optogenetic manipulation of neurons in the brain slice using a DMD-based projector.

PubMed

Sakai, Seiichiro; Ueno, Kenichi; Ishizuka, Toru; Yawo, Hiromu

2013-01-01

Optical manipulation technologies greatly advanced the understanding of the neuronal network and its dysfunctions. To achieve patterned and parallel optical switching, we developed a microscopic illumination system using a commercial DMD-based projector and a software program. The spatiotemporal patterning of the system was evaluated using acute slices of the hippocampus. The neural activity was optically manipulated, positively by the combination of channelrhodopsin-2 (ChR2) and blue light, and negatively by the combination of archaerhodopsin-T (ArchT) and green light. It is suggested that our projector-managing optical system (PMOS) would effectively facilitate the optogenetic analyses of neurons and their circuits. Copyright © 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Variable Saline Concentrations for Initial Resuscitation Following Polytrauma

DTIC Science & Technology

2017-02-22

sagittal suture between the coronal and lambdoid suture lines. Head injury was induced by dropping a cylindrical rod weighing 400 grams from 1.5 cm...injury. Brain samples were perfusion fixed and evaluated for extent of injury with hematoxylin and eosin staining . 3.5 Capillary Leak and Blood...Distribution is unlimited. Cleared, 88PA, Case # 2017-2329, 15 May 2017. 4.8 Histology Hematoxylin and eosin staining demonstrated no differences

MRI Brain Tumor Segmentation and Necrosis Detection Using Adaptive Sobolev Snakes.

PubMed

Nakhmani, Arie; Kikinis, Ron; Tannenbaum, Allen

2014-03-21

Brain tumor segmentation in brain MRI volumes is used in neurosurgical planning and illness staging. It is important to explore the tumor shape and necrosis regions at different points of time to evaluate the disease progression. We propose an algorithm for semi-automatic tumor segmentation and necrosis detection. Our algorithm consists of three parts: conversion of MRI volume to a probability space based on the on-line learned model, tumor probability density estimation, and adaptive segmentation in the probability space. We use manually selected acceptance and rejection classes on a single MRI slice to learn the background and foreground statistical models. Then, we propagate this model to all MRI slices to compute the most probable regions of the tumor. Anisotropic 3D diffusion is used to estimate the probability density. Finally, the estimated density is segmented by the Sobolev active contour (snake) algorithm to select smoothed regions of the maximum tumor probability. The segmentation approach is robust to noise and not very sensitive to the manual initialization in the volumes tested. Also, it is appropriate for low contrast imagery. The irregular necrosis regions are detected by using the outliers of the probability distribution inside the segmented region. The necrosis regions of small width are removed due to a high probability of noisy measurements. The MRI volume segmentation results obtained by our algorithm are very similar to expert manual segmentation.

MRI brain tumor segmentation and necrosis detection using adaptive Sobolev snakes

NASA Astrophysics Data System (ADS)

Nakhmani, Arie; Kikinis, Ron; Tannenbaum, Allen

2014-03-01

Brain tumor segmentation in brain MRI volumes is used in neurosurgical planning and illness staging. It is important to explore the tumor shape and necrosis regions at di erent points of time to evaluate the disease progression. We propose an algorithm for semi-automatic tumor segmentation and necrosis detection. Our algorithm consists of three parts: conversion of MRI volume to a probability space based on the on-line learned model, tumor probability density estimation, and adaptive segmentation in the probability space. We use manually selected acceptance and rejection classes on a single MRI slice to learn the background and foreground statistical models. Then, we propagate this model to all MRI slices to compute the most probable regions of the tumor. Anisotropic 3D di usion is used to estimate the probability density. Finally, the estimated density is segmented by the Sobolev active contour (snake) algorithm to select smoothed regions of the maximum tumor probability. The segmentation approach is robust to noise and not very sensitive to the manual initialization in the volumes tested. Also, it is appropriate for low contrast imagery. The irregular necrosis regions are detected by using the outliers of the probability distribution inside the segmented region. The necrosis regions of small width are removed due to a high probability of noisy measurements. The MRI volume segmentation results obtained by our algorithm are very similar to expert manual segmentation.

On the role of calcium ions in the regulation of glycogenolysis in mouse brain cortical slices.

PubMed

Ververken, D; Van Veldhoven, P; Proost, C; Carton, H; De Wulf, H

1982-05-01

Using mouse brain cortical slices, we investigated the relative roles of cyclic AMP and of calcium ions as the intracellular messengers for the activation of glycogen phosphorylase (EC 2.4.1.1; alpha-1,4-glucan:orthophosphate glucosyltransferase) induced by noradrenaline and by depolarization. Activation of phosphorylase by 100 microM noradrenaline is mediated by beta-adrenergic receptors and does not require the copresence of adenosine. The role of the concomitant small increase in cyclic AMP is questioned. Short-term treatment with EGTA or LaCl3 abolishes the noradrenaline activation of phosphorylase, pointing to a critical role of extracellular calcium. Depolarization by 25 mM K+ or 100 microM veratridine produces a rapid and large (fourfold) activation of phosphorylase. Only veratridine increases the cyclic AMP levels; exogenous adenosine deaminase essentially blocks this cyclic AMP accumulation but not the phosphorylase activation. A half-maximal activation of phosphorylase occurs at about 12 mM K+. Addition of EGTA or LaCl3 reduces the effect of both depolarizations to a slight and transient activation of phosphorylase. These results indicate that activation of glycogen phosphorylase by K+ or veratridine occurs by a cyclic AMP-independent and calcium-dependent mechanism. The calcium dependency of brain phosphorylase kinase renders this kinase the prime target enzyme for regulation of glycogenolysis by calcium ions.

Segmentation of neuroanatomy in magnetic resonance images

NASA Astrophysics Data System (ADS)

Simmons, Andrew; Arridge, Simon R.; Barker, G. J.; Tofts, Paul S.

1992-06-01

Segmentation in neurological magnetic resonance imaging (MRI) is necessary for feature extraction, volume measurement and for the three-dimensional display of neuroanatomy. Automated and semi-automated methods offer considerable advantages over manual methods because of their lack of subjectivity, their data reduction capabilities, and the time savings they give. We have used dual echo multi-slice spin-echo data sets which take advantage of the intrinsically multispectral nature of MRI. As a pre-processing step, a rf non-uniformity correction is applied and if the data is noisy the images are smoothed using a non-isotropic blurring method. Edge-based processing is used to identify the skin (the major outer contour) and the eyes. Edge-focusing has been used to significantly simplify edge images and thus allow simple postprocessing to pick out the brain contour in each slice of the data set. Edge- focusing is a technique which locates significant edges using a high degree of smoothing at a coarse level and tracks these edges to a fine level where the edges can be determined with high positional accuracy. Both 2-D and 3-D edge-detection methods have been compared. Once isolated, the brain is further processed to identify CSF, and, depending upon the MR pulse sequence used, the brain itself may be sub-divided into gray matter and white matter using semi-automatic contrast enhancement and clustering methods.

The horizontal brain slice preparation: a novel approach for visualizing and recording from all layers of the tadpole tectum.

PubMed

Hamodi, Ali S; Pratt, Kara G

2015-01-01

The Xenopus tadpole optic tectum is a multisensory processing center that receives direct visual input as well as nonvisual mechanosensory input. The tectal neurons that comprise the optic tectum are organized into layers. These neurons project their dendrites laterally into the neuropil where visual inputs target the distal region of the dendrite and nonvisual inputs target the proximal region of the same dendrite. The Xenopus tadpole tectum is a popular model to study the development of sensory circuits. However, whole cell patch-clamp electrophysiological studies of the tadpole tectum (using the whole brain or in vivo preparations) have focused solely on the deep-layer tectal neurons because only neurons of the deep layer are visible and accessible for whole cell electrophysiological recordings. As a result, whereas the development and plasticity of these deep-layer neurons has been well-studied, essentially nothing has been reported about the electrophysiology of neurons residing beyond this layer. Hence, there exists a large gap in our understanding about the functional development of the amphibian tectum as a whole. To remedy this, we developed a novel isolated brain preparation that allows visualizing and recording from all layers of the tectum. We refer to this preparation as the "horizontal brain slice preparation." Here, we describe the preparation method and illustrate how it can be used to characterize the electrophysiology of neurons across all of the layers of the tectum as well as the spatial pattern of synaptic input from the different sensory modalities. Copyright © 2015 the American Physiological Society.

Automatic Semantic Segmentation of Brain Gliomas from MRI Images Using a Deep Cascaded Neural Network

PubMed Central

Mao, Lei; Liu, Chang; Xiong, Shuyu

2018-01-01

Brain tumors can appear anywhere in the brain and have vastly different sizes and morphology. Additionally, these tumors are often diffused and poorly contrasted. Consequently, the segmentation of brain tumor and intratumor subregions using magnetic resonance imaging (MRI) data with minimal human interventions remains a challenging task. In this paper, we present a novel fully automatic segmentation method from MRI data containing in vivo brain gliomas. This approach can not only localize the entire tumor region but can also accurately segment the intratumor structure. The proposed work was based on a cascaded deep learning convolutional neural network consisting of two subnetworks: (1) a tumor localization network (TLN) and (2) an intratumor classification network (ITCN). The TLN, a fully convolutional network (FCN) in conjunction with the transfer learning technology, was used to first process MRI data. The goal of the first subnetwork was to define the tumor region from an MRI slice. Then, the ITCN was used to label the defined tumor region into multiple subregions. Particularly, ITCN exploited a convolutional neural network (CNN) with deeper architecture and smaller kernel. The proposed approach was validated on multimodal brain tumor segmentation (BRATS 2015) datasets, which contain 220 high-grade glioma (HGG) and 54 low-grade glioma (LGG) cases. Dice similarity coefficient (DSC), positive predictive value (PPV), and sensitivity were used as evaluation metrics. Our experimental results indicated that our method could obtain the promising segmentation results and had a faster segmentation speed. More specifically, the proposed method obtained comparable and overall better DSC values (0.89, 0.77, and 0.80) on the combined (HGG + LGG) testing set, as compared to other methods reported in the literature. Additionally, the proposed approach was able to complete a segmentation task at a rate of 1.54 seconds per slice. PMID:29755716

Fluoride Induces a Volume Reduction in CA1 Hippocampal Slices Via MAP Kinase Pathway Through Volume Regulated Anion Channels

PubMed Central

Lee, Jaekwang; Han, Young-Eun; Favorov, Oleg; Tommerdahl, Mark; Whitsel, Barry

2016-01-01

Regulation of cell volume is an important aspect of cellular homeostasis during neural activity. This volume regulation is thought to be mediated by activation of specific transporters, aquaporin, and volume regulated anion channels (VRAC). In cultured astrocytes, it was reported that swelling-induced mitogen-activated protein (MAP) kinase activation is required to open VRAC, which are thought to be important in regulatory volume decrease and in the response of CNS to trauma and excitotoxicity. It has been also described that sodium fluoride (NaF), a recognized G-protein activator and protein phosphatase inhibitor, leads to a significant MAP kinase activation in endothelial cells. However, NaF's effect in volume regulation in the brain is not known yet. Here, we investigated the mechanism of NaF-induced volume change in rat and mouse hippocampal slices using intrinsic optical signal (IOS) recording, in which we measured relative changes in intracellular and extracellular volume as changes in light transmittance through brain slices. We found that NaF (1~5 mM) application induced a reduction in light transmittance (decreased volume) in CA1 hippocampus, which was completely reversed by MAP kinase inhibitor U0126 (10 µM). We also observed that NaF-induced volume reduction was blocked by anion channel blockers, suggesting that NaF-induced volume reduction could be mediated by VRAC. Overall, our results propose a novel molecular mechanism of NaF-induced volume reduction via MAP kinase signaling pathway by activation of VRAC. PMID:27122993

Acute and chronic efficacy of Bumetanide in an in vitro model of post-traumatic epileptogenesis

PubMed Central

Dzhala, Volodymyr; Staley, Kevin

2014-01-01

Background Seizures triggered by acute injuries to the developing brain respond poorly to first-line medications that target the inhibitory chloride-permeable GABAA-receptor. Neuronal injury is associated with profound increases in cytoplasmic chloride ([Cl−]i) resulting in depolarizing GABA signaling, higher seizure propensity and limited efficacy of GABAergic anticonvulsants. The Na+-K+-2Cl− (NKCC1) co-transporter blocker bumetanide reduces [Cl−]i and causes more negative GABA equilibrium potential in injured neurons. We therefore tested both the acute and chronic efficacy of bumetanide on early post-traumatic ictal-like epileptiform discharges and epileptogenesis. Methods Acute hippocampal slices were used as a model of severe traumatic brain injury and post-traumatic epileptogenesis. Hippocampal slices were then incubated for three weeks. After a one week latent period slice cultures developed chronic spontaneous ictal-like discharges. The anticonvulsant and antiepileptogenic efficacy of bumetanide, phenobarbital and the combination of these drugs was studied. Results Bumetanide reduced the frequency and power of early post-traumatic ictal-like discharges in vitro and enhanced the anticonvulsant efficacy of phenobarbital. Continuous two-three week administration of bumetanide as well as phenobarbital in combination with bumetanide failed to prevent post-traumatic ictal-like discharges and epileptogenesis. Conclusions Our data demonstrate a persistent contribution of NKCC1 co-transport in post-traumatic ictal-like activity, presumably as a consequence of chronic alterations in neuronal chloride homeostasis and GABA-mediated inhibition. New strategies for more effective reduction in post-traumatic and seizure-induced [Cl−]i accumulation could provide the basis for effective treatments for post-traumatic epileptogenesis and the resultant seizures. PMID:25495911

High frequency stimulation abolishes thalamic network oscillations: an electrophysiological and computational analysis

NASA Astrophysics Data System (ADS)

Lee, Kendall H.; Hitti, Frederick L.; Chang, Su-Youne; Lee, Dongchul C.; Roberts, David W.; McIntyre, Cameron C.; Leiter, James C.

2011-08-01

Deep brain stimulation (DBS) of the thalamus has been demonstrated to be effective for the treatment of epilepsy. To investigate the mechanism of action of thalamic DBS, we examined the effects of high frequency stimulation (HFS) on spindle oscillations in thalamic brain slices from ferrets. We recorded intracellular and extracellular electrophysiological activity in the nucleus reticularis thalami (nRt) and in thalamocortical relay (TC) neurons in the lateral geniculate nucleus, stimulated the slice using a concentric bipolar electrode, and recorded the level of glutamate within the slice. HFS (100 Hz) of TC neurons generated excitatory post-synaptic potentials, increased the number of action potentials in both TC and nRt neurons, reduced the input resistance, increased the extracellular glutamate concentration, and abolished spindle wave oscillations. HFS of the nRt also suppressed spindle oscillations. In both locations, HFS was associated with significant and persistent elevation in extracellular glutamate levels and suppressed spindle oscillations for many seconds after the cessation of stimulation. We simulated HFS within a computational model of the thalamic network, and HFS also disrupted spindle wave activity, but the suppression of spindle activity was short-lived. Simulated HFS disrupted spindle activity for prolonged periods of time only after glutamate release and glutamate-mediated activation of a hyperpolarization-activated current (Ih) was incorporated into the model. Our results suggest that the mechanism of action of thalamic DBS as used in epilepsy may involve the prolonged release of glutamate, which in turn modulates specific ion channels such as Ih, decreases neuronal input resistance, and abolishes thalamic network oscillatory activity.

Clinical application of Half Fourier Acquisition Single Shot Turbo Spin Echo (HASTE) imaging accelerated by simultaneous multi-slice acquisition.

PubMed

Schulz, Jenni; P Marques, José; Ter Telgte, Annemieke; van Dorst, Anouk; de Leeuw, Frank-Erik; Meijer, Frederick J A; Norris, David G

2018-01-01

As a single-shot sequence with a long train of refocusing pulses, Half-Fourier Acquisition Single-Shot Turbo-Spin-Echo (HASTE) suffers from high power deposition limiting use at high resolutions and high field strengths, particularly if combined with acceleration techniques such as simultaneous multi-slice (SMS) imaging. Using a combination of multiband (MB)-excitation and PINS-refocusing pulses will effectively accelerate the acquisition time while staying within the SAR limitations. In particular, uncooperative and young patients will profit from the speed of the MB-PINS HASTE sequence, as clinical diagnosis can be possible without sedation. Materials and MethodsMB-excitation and PINS-refocusing pulses were incorporated into a HASTE-sequence with blipped CAIPIRINHA and TRAPS including an internal FLASH reference scan for online reconstruction. Whole brain MB-PINS HASTE data were acquired on a Siemens 3T-Prisma system from 10 individuals and compared to a clinical HASTE protocol. ResultsThe proposed MB-PINS HASTE protocol accelerates the acquisition by about a factor 2 compared to the clinical HASTE. The diagnostic image quality proved to be comparable for both sequences for the evaluation of the overall aspect of the brain, the detection of white matter changes and areas of tissue loss, and for the evaluation of the CSF spaces although artifacts were more frequently encountered with MB-PINS HASTE. ConclusionsMB-PINS HASTE enables acquisition of slice accelerated highly T2-weighted images and provides good diagnostic image quality while reducing acquisition time. Copyright © 2017 Elsevier B.V. All rights reserved.

Sniffer patch laser uncaging response (SPLURgE): an assay of regional differences in allosteric receptor modulation and neurotransmitter clearance

PubMed Central

Christian, Catherine A.

2013-01-01

Allosteric modulators exert actions on neurotransmitter receptors by positively or negatively altering the effective response of these receptors to their respective neurotransmitter. γ-Aminobutyric acid (GABA) type A ionotropic receptors (GABAARs) are major targets for allosteric modulators such as benzodiazepines, neurosteroids, and barbiturates. Analysis of substances that produce similar effects has been hampered by the lack of techniques to assess the localization and function of such agents in brain slices. Here we describe measurement of the sniffer patch laser uncaging response (SPLURgE), which combines the sniffer patch recording configuration with laser photolysis of caged GABA. This methodology enables the detection of allosteric GABAAR modulators endogenously present in discrete areas of the brain slice and allows for the application of exogenous GABA with spatiotemporal control without altering the release and localization of endogenous modulators within the slice. Here we demonstrate the development and use of this technique for the measurement of allosteric modulation in different areas of the thalamus. Application of this technique will be useful in determining whether a lack of modulatory effect on a particular category of neurons or receptors is due to insensitivity to allosteric modulation or a lack of local release of endogenous ligand. We also demonstrate that this technique can be used to investigate GABA diffusion and uptake. This method thus provides a biosensor assay for rapid detection of endogenous GABAAR modulators and has the potential to aid studies of allosteric modulators that exert effects on other classes of neurotransmitter receptors, such as glutamate, acetylcholine, or glycine receptors. PMID:23843428

Sniffer patch laser uncaging response (SPLURgE): an assay of regional differences in allosteric receptor modulation and neurotransmitter clearance.

PubMed

Christian, Catherine A; Huguenard, John R

2013-10-01

Allosteric modulators exert actions on neurotransmitter receptors by positively or negatively altering the effective response of these receptors to their respective neurotransmitter. γ-Aminobutyric acid (GABA) type A ionotropic receptors (GABAARs) are major targets for allosteric modulators such as benzodiazepines, neurosteroids, and barbiturates. Analysis of substances that produce similar effects has been hampered by the lack of techniques to assess the localization and function of such agents in brain slices. Here we describe measurement of the sniffer patch laser uncaging response (SPLURgE), which combines the sniffer patch recording configuration with laser photolysis of caged GABA. This methodology enables the detection of allosteric GABAAR modulators endogenously present in discrete areas of the brain slice and allows for the application of exogenous GABA with spatiotemporal control without altering the release and localization of endogenous modulators within the slice. Here we demonstrate the development and use of this technique for the measurement of allosteric modulation in different areas of the thalamus. Application of this technique will be useful in determining whether a lack of modulatory effect on a particular category of neurons or receptors is due to insensitivity to allosteric modulation or a lack of local release of endogenous ligand. We also demonstrate that this technique can be used to investigate GABA diffusion and uptake. This method thus provides a biosensor assay for rapid detection of endogenous GABAAR modulators and has the potential to aid studies of allosteric modulators that exert effects on other classes of neurotransmitter receptors, such as glutamate, acetylcholine, or glycine receptors.

ANATOMICAL STUDY OF CRANIAL NERVE EMERGENCE AND SKULL FORAMINA IN THE HORSE USING MAGNETIC RESONANCE IMAGING AND COMPUTED TOMOGRAPHY.

PubMed

Gonçalves, Rita; Malalana, Fernando; McConnell, James Fraser; Maddox, Thomas

2015-01-01

For accurate interpretation of magnetic resonance (MR) images of the equine brain, knowledge of the normal cross-sectional anatomy of the brain and associated structures (such as the cranial nerves) is essential. The purpose of this prospective cadaver study was to describe and compare MRI and computed tomography (CT) anatomy of cranial nerves' origins and associated skull foramina in a sample of five horses. All horses were presented for euthanasia for reasons unrelated to the head. Heads were collected posteuthanasia and T2-weighted MR images were obtained in the transverse, sagittal, and dorsal planes. Thin-slice MR sequences were also acquired using transverse 3D-CISS sequences that allowed mutliplanar reformatting. Transverse thin-slice CT images were acquired and multiplanar reformatting was used to create comparative images. Magnetic resonance imaging consistently allowed visualization of cranial nerves II, V, VII, VIII, and XII in all horses. The cranial nerves III, IV, and VI were identifiable as a group despite difficulties in identification of individual nerves. The group of cranial nerves IX, X, and XI were identified in 4/5 horses although the region where they exited the skull was identified in all cases. The course of nerves II and V could be followed on several slices and the main divisions of cranial nerve V could be distinguished in all cases. In conclusion, CT allowed clear visualization of the skull foramina and occasionally the nerves themselves, facilitating identification of the nerves for comparison with MRI images. © 2015 American College of Veterinary Radiology.

Endogenous GFAP-Positive Neural Stem/Progenitor Cells in the Postnatal Mouse Cortex Are Activated following Traumatic Brain Injury

PubMed Central

Ahmed, Aminul I.; Shtaya, Anan B.; Zaben, Malik J.; Owens, Emma V.; Kiecker, Clemens

2012-01-01

Abstract Interest in promoting regeneration of the injured nervous system has recently turned toward the use of endogenous stem cells. Elucidating cues involved in driving these precursor cells out of quiescence following injury, and the signals that drive them toward neuronal and glial lineages, will help to harness these cells for repair. Using a biomechanically validated in vitro organotypic stretch injury model, cortico-hippocampal slices from postnatal mice were cultured and a stretch injury equivalent to a severe traumatic brain injury (TBI) applied. In uninjured cortex, proliferative potential under in vitro conditions is virtually absent in older slices (equivalent postnatal day 15 compared to 8). However, following a severe stretch injury, this potential is restored in injured outer cortex. Using slices from mice expressing a fluorescent reporter on the human glial fibrillary acidic protein (GFAP) promoter, we show that GFAP+ cells account for the majority of proliferating neurospheres formed, and that these cells are likely to arise from the cortical parenchyma and not from the subventricular zone. Moreover, we provide evidence for a correlation between upregulation of sonic hedgehog signaling, a pathway known to regulate stem cell proliferation, and this restoration of regenerative potential following TBI. Our results indicate that a source of quiescent endogenous stem cells residing in the cortex and subcortical tissue proliferate in vitro following TBI. Moreover, these proliferating cells are multipotent and are derived mostly from GFAP-expressing cells. This raises the possibility of using this endogenous source of stem cells for repair following TBI. PMID:21895532

Benzothiazepine CGP37157 and its isosteric 2'-methyl analogue provide neuroprotection and block cell calcium entry.

PubMed

González-Lafuente, Laura; Egea, Javier; León, Rafael; Martínez-Sanz, Francisco J; Monjas, Leticia; Perez, Concepción; Merino, Cristina; García-De Diego, Antonio M; Rodríguez-Franco, María I; García, Antonio G; Villarroya, Mercedes; López, Manuela G; de Los Ríos, Cristóbal

2012-07-18

Benzothiazepine CGP37157 is widely used as tool to explore the role of mitochondria in cell Ca(2+) handling, by its blocking effect of the mitochondria Na(+)/Ca(2+) exchanger. Recently, CGP37157 has shown to exhibit neuroprotective properties. In the trend to improve its neuroprotection profile, we have synthesized ITH12505, an isosteric analogue having a methyl instead of chlorine at C2' of the phenyl ring. ITH12505 has exerted neuroprotective properties similar to CGP37157 in chromaffin cells and hippocampal slices stressed with veratridine. Also, both compounds afforded neuroprotection in hippocampal slices stressed with glutamate. However, while ITH12505 elicited protection in SH-SY5Y cells stressed with oligomycin A/rotenone, CGP37157 was ineffective. In hippocampal slices subjected to oxygen/glucose deprivation plus reoxygenation, ITH12505 offered protection at 3-30 μM, while CGP37157 only protected at 30 μM. Both compounds caused blockade of Ca(2+) channels in high K(+)-depolarized SH-SY5Y cells. An in vitro experiment for assaying central nervous system penetration (PAMPA-BBB; parallel artificial membrane permeability assay for blood-brain barrier) revealed that both compounds could cross the blood-brain barrier, thus reaching their biological targets in the central nervous system. In conclusion, by causing a mild isosteric replacement in the benzothiazepine CGP37157, we have obtained ITH12505, with improved neuroprotective properties. These findings may inspire the design and synthesis of new benzothiazepines targeting mitochondrial Na(+)/Ca(2+) exchanger and L-type voltage-dependent Ca(2+) channels, having antioxidant properties.

Benzothiazepine CGP37157 and Its Isosteric 2′-Methyl Analogue Provide Neuroprotection and Block Cell Calcium Entry

PubMed Central

2012-01-01

Benzothiazepine CGP37157 is widely used as tool to explore the role of mitochondria in cell Ca2+ handling, by its blocking effect of the mitochondria Na+/Ca2+ exchanger. Recently, CGP37157 has shown to exhibit neuroprotective properties. In the trend to improve its neuroprotection profile, we have synthesized ITH12505, an isosteric analogue having a methyl instead of chlorine at C2′ of the phenyl ring. ITH12505 has exerted neuroprotective properties similar to CGP37157 in chromaffin cells and hippocampal slices stressed with veratridine. Also, both compounds afforded neuroprotection in hippocampal slices stressed with glutamate. However, while ITH12505 elicited protection in SH-SY5Y cells stressed with oligomycin A/rotenone, CGP37157 was ineffective. In hippocampal slices subjected to oxygen/glucose deprivation plus reoxygenation, ITH12505 offered protection at 3–30 μM, while CGP37157 only protected at 30 μM. Both compounds caused blockade of Ca2+ channels in high K+-depolarized SH-SY5Y cells. An in vitro experiment for assaying central nervous system penetration (PAMPA-BBB; parallel artificial membrane permeability assay for blood-brain barrier) revealed that both compounds could cross the blood–brain barrier, thus reaching their biological targets in the central nervous system. In conclusion, by causing a mild isosteric replacement in the benzothiazepine CGP37157, we have obtained ITH12505, with improved neuroprotective properties. These findings may inspire the design and synthesis of new benzothiazepines targeting mitochondrial Na+/Ca2+ exchanger and L-type voltage-dependent Ca2+ channels, having antioxidant properties. PMID:22860221

Neural interface of mirror therapy in chronic stroke patients: a functional magnetic resonance imaging study.

PubMed

Bhasin, Ashu; Padma Srivastava, M V; Kumaran, Senthil S; Bhatia, Rohit; Mohanty, Sujata

2012-01-01

Recovery in stroke is mediated by neural plasticity. Neuro-restorative therapies improve recovery after stroke by promoting repair and function. Mirror neuron system (MNS) has been studied widely in humans in stroke and phantom sensations. Study subjects included 20 patients with chronic stroke and 10 healthy controls. Patients had clinical disease-severity scores, functional magnetic resonance imaging (fMRI) and diffuse tensor imaging (DTI) at baseline, 8 and at 24 weeks. Block design with alternate baseline and activation cycles was used with a total of 90 whole brain echo planar imaging (EPI) measurements (timed repetition (TR) = 4520 ms, timed echo (TE) = 44 ms, slices = 31, slice thickness = 4 mm, EPI factor 127, matrix = 128 × 128, FOV = 230 mm). Whole brain T1-weighted images were acquired using 3D sequence (MPRage) with 120 contiguous slices of 1.0 mm thickness. The mirror therapy was aimed via laptop system integrated with web camera, mirroring the movement of the unaffected hand. This therapy was administered for 5 days in a week for 60-90 min for 8 weeks. All the patients showed statistical significant improvement in Fugl Meyer and modified Barthel Index (P < 0.05) whereas the change in Medical Research Council (MRC) power grade was not significant post-therapy (8 weeks). There was an increase in the laterality index (LI) of ipsilesional BA 4 and BA 6 at 8 weeks exhibiting recruitment and focusing principles of neural plasticity. Mirror therapy simulated the "action-observation" hypothesis exhibiting recovery in patients with chronic stroke. Therapy induced cortical reorganization was also observed from our study.

Brain-derived neurotrophic factor transgenic mice exhibit passive avoidance deficits, increased seizure severity and in vitro hyperexcitability in the hippocampus and entorhinal cortex.

PubMed

Croll, S D; Suri, C; Compton, D L; Simmons, M V; Yancopoulos, G D; Lindsay, R M; Wiegand, S J; Rudge, J S; Scharfman, H E

1999-01-01

Transgenic mice overexpressing brain-derived neurotrophic factor from the beta-actin promoter were tested for behavioral, gross anatomical and physiological abnormalities. Brain-derived neurotrophic factor messenger RNA overexpression was widespread throughout brain. Overexpression declined with age, such that levels of overexpression decreased sharply by nine months. Brain-derived neurotrophic factor transgenic mice had no gross deformities or behavioral abnormalities. However, they showed a significant passive avoidance deficit. This deficit was dependent on continued overexpression, and resolved with age as brain-derived neurotrophic factor transcripts decreased. In addition, the brain-derived neurotrophic factor transgenic mice showed increased seizure severity in response to kainic acid. Hippocampal slices from brain-derived neurotrophic factor transgenic mice showed hyperexcitability in area CA3 and entorhinal cortex, but not in dentate gyrus. Finally, area CA1 long-term potentiation was disrupted, indicating abnormal plasticity. Our data suggest that overexpression of brain-derived neurotrophic factor in the brain can interfere with normal brain function by causing learning impairments and increased excitability. The results also support the hypothesis that excess brain-derived neurotrophic factor could be pro-convulsant in the limbic system.

Radiological outcomes of pinless navigation in total knee arthroplasty: a randomized controlled trial.

PubMed

Chen, Jerry Yongqiang; Chin, Pak Lin; Li, Zongxian; Yew, Andy Khye Soon; Tay, Darren Keng Jin; Chia, Shi-Lu; Lo, Ngai Nung; Yeo, Seng Jin

2015-12-01

This study aimed to investigate the accuracy of pinless navigation (BrainLAB(®) VectorVision(®) Knee 2.5 Navigation System) as an intra-operative alignment guide in total knee arthroplasty (TKA). The authors hypothesized that pinless navigation would reduce the proportion of outliers in conventional TKA, without a significant increase in the duration of surgery. Between 2011 and 2012, 100 patients scheduled for a unilateral primary TKA were randomized into two groups: pinless navigation and conventional surgery. All TKAs were performed with the surgical aim of achieving neutral coronal alignment with a 180° mechanical axis. The primary outcomes of this study were post-operative radiographic assessment of lower limb alignment using hip-knee-ankle angle (HKA) and components placement using coronal femoral-component angle (CFA) and coronal tibia-component angle (CTA). There was a smaller proportion of outliers for HKA, CFA and CTA at 10, 2 and 2 % respectively, in the pinless navigation group, compared to 32, 16 and 16 %, respectively, in the conventional group (p = 0.013, p = 0.032 and p = 0.032, respectively). The mean CFA was also more accurate at 90° in the pinless navigation group compared to 91° in the conventional group (p = 0.002). There was no difference in the duration of surgery between the two groups (n.s.). Pinless navigation improves lower limb alignment and components placement without a significant increase in the duration of surgery. The authors recommend the use of pinless navigation to verify the coronal alignments of conventional cutting blocks in TKA before the bone cuts are made. I.

Satisfactory rate of post-processing visualization of fetal cerebral axial, sagittal, and coronal planes from three-dimensional volumes acquired in routine second trimester ultrasound practice by sonographers of peripheral centers.

PubMed

Rizzo, Giuseppe; Pietrolucci, Maria Elena; Capece, Giuseppe; Cimmino, Ernesto; Colosi, Enrico; Ferrentino, Salvatore; Sica, Carmine; Di Meglio, Aniello; Arduini, Domenico

2011-08-01

The aim of this study was to evaluate the feasibility to visualize central nervous system (CNS) diagnostic planes from three-dimensional (3D) brain volumes obtained in ultrasound facilities with no specific experience in fetal neurosonography. Five sonographers prospectively recorded transabdominal 3D CNS volumes starting from an axial approach on 500 consecutive pregnancies at 19-24 weeks of gestation undergoing routine ultrasound examination. Volumes were sent to the referral center (Department of Obstetrics and Gynecology, Università Roma Tor Vergata, Italy) and two independent reviewers with experience in 3D ultrasound assessed their quality in the display of axial, coronal, and sagittal planes. CNS volumes were acquired in 491/500 pregnancies (98.2%). The two reviewers acknowledged the presence of satisfactory images with a visualization rate ranging respectively between 95.1% and 97.14% for axial planes, 73.72% and 87.16% for coronal planes, and 78.41% and 94.29% for sagittal planes. The agreement rate between the two reviewers as expressed by Cohen's kappa coefficient was >0.87 for axial planes, >0.89 for coronal planes, and >0.94 for sagittal planes. The presence of a maternal body mass index >30 alters the probability of achieving satisfactory CNS views, while existence of previous maternal lower abdomen surgery does not affect the quality of the reconstructed planes. CNS volumes acquired by 3D ultrasonography in peripheral centers showed a quality high enough to allow a detailed fetal neurosonogram.

Evaluation of Effective Parameters on Quality of Magnetic Resonance Imaging-computed Tomography Image Fusion in Head and Neck Tumors for Application in Treatment Planning.

PubMed

Shirvani, Atefeh; Jabbari, Keyvan; Amouheidari, Alireza

2017-01-01

In radiation therapy, computed tomography (CT) simulation is used for treatment planning to define the location of tumor. Magnetic resonance imaging (MRI)-CT image fusion leads to more efficient tumor contouring. This work tried to identify the practical issues for the combination of CT and MRI images in real clinical cases. The effect of various factors is evaluated on image fusion quality. In this study, the data of thirty patients with brain tumors were used for image fusion. The effect of several parameters on possibility and quality of image fusion was evaluated. These parameters include angles of the patient's head on the bed, slices thickness, slice gap, and height of the patient's head. According to the results, the first dominating factor on quality of image fusion was the difference slice gap between CT and MRI images (cor = 0.86, P < 0.005) and second factor was the angle between CT and MRI slice in the sagittal plane (cor = 0.75, P < 0.005). In 20% of patients, this angle was more than 28° and image fusion was not efficient. In 17% of patients, difference slice gap in CT and MRI was >4 cm and image fusion quality was <25%. The most important problem in image fusion is that MRI images are taken without regard to their use in treatment planning. In general, parameters related to the patient position during MRI imaging should be chosen to be consistent with CT images of the patient in terms of location and angle.

The use of three-dimensional printing to produce in vitro slice chambers

PubMed Central

Hyde, James; MacNicol, Melanie; Odle, Angela; Garcia-Rill, Edgar

2014-01-01

Background In recent years, 3D printing technology has become inexpensive and simple enough that any lab can own and use one of these printers. New Method We explored the potential use of 3D printers for quickly and easily producing in vitro slice chambers for patch clamp electrophysiology. Slice chambers were produced using five available plastics: ABS, PLA, Nylon 618, Nylon 680, and T-glase. These “lab-made” chambers were also made using stereolithography through a professional printing service (Shapeways). This study measured intrinsic membrane properties of neurons in the brain stem pedunculopontine nucleus (PPN) and layer V pyramidal neurons in retrosplenial cortex. Results Nylon 680 and T-glase significantly hyperpolarized PPN neurons. ABS increased input resistance, decreased action potential amplitude, and increased firing frequency in pyramidal cortical neurons. To test long term exposure to each plastic, human neuroblastoma SHSY5Y cell cultures were exposed to each plastic for 1 week. ABS decreased cell counts while Nylon 618 and Shapeways plastics eliminated cells. Primary mouse pituitary cultures were also tested for 24-hour exposure. ABS decreased cell counts while Nylon 618 and Shapeways plastics decreased cell counts. Comparison to Existing Methods Chambers can be quickly and inexpensively printed in the lab. ABS, PLA, Nylon 680, and T-glase plastics would suffice for many experiments instead of commercially produced slice chambers. Conclusions While these technologies are still in their infancy, they represent a powerful addition to the lab environment. With careful selection of print material, slice chambers can be quickly and inexpensively manufactured in the lab. PMID:25251556

Development of a method to evaluate glutamate receptor function in rat barrel cortex slices.

PubMed

Lehohla, M; Russell, V; Kellaway, L; Govender, A

2000-12-01

The rat is a nocturnal animal and uses its vibrissae extensively to navigate its environment. The vibrissae are linked to a highly organized part of the sensory cortex, called the barrel cortex which contains spiny neurons that receive whisker specific thalamic input and distribute their output mainly within the cortical column. The aim of the present study was to develop a method to evaluate glutamate receptor function in the rat barrel cortex. Long Evans rats (90-160 g) were killed by cervical dislocation and decapitated. The brain was rapidly removed, cooled in a continuously oxygenated, ice-cold Hepes buffer (pH 7.4) and sliced using a vibratome to produce 0.35 mm slices. The barrel cortex was dissected from slices corresponding to 8.6 to 4.8 mm anterior to the interaural line and divided into rostral, middle and caudal regions. Depolarization-induced uptake of 45Ca2+ was achieved by incubating test slices in a high K+ (62.5 mM) buffer for 2 minutes at 35 degrees C. Potassium-stimulated uptake of 45Ca2+ into the rostral region was significantly lower than into middle and caudal regions of the barrel cortex. Glutamate had no effect. NMDA significantly increased uptake of 45Ca2+ into all regions of the barrel cortex. The technique is useful in determining NMDA receptor function and will be applied to study differences between spontaneously hypertensive rats (SHR) that are used as a model for attention deficit disorder and their normotensive control rats.

Nuclear medicine image registration by spatially noncoherent interferometry.

PubMed

Scheiber, C; Malet, Y; Sirat, G; Grucker, D

2000-02-01

This article introduces a technique for obtaining high-resolution body contour data in the same coordinate frame as that of a rotating gamma camera, using a miniature range finder, the conoscope, mounted on the camera gantry. One potential application of the technique is accurate coregistration in longitudinal brain SPECT studies, using the face of the patient (or "mask"), instead of SPECT slices, to coregister subsequent acquisitions involving the brain. Conoscopic holography is an interferometry technique that relies on spatially incoherent light interference in birefringent crystals. In this study, the conoscope was used to measure the absolute distance (Z) between a light source reflected from the skin and its observation plane. This light was emitted by a 0.2-mW laser diode. A scanning system was used to image the face during SPECT acquisition. The system consisted of a motor-driven mirror (Y axis) and the gamma-camera gantry (1 profile was obtained for each rotation step, X axis). The system was calibrated to place the conoscopic measurements and SPECT slices in the same coordinate frame. Through a simple and robust calibration of the system, the SE for measurements performed on geometric shapes was less than 2 mm, i.e., less than the actual pixel size of the SPECT data. Biometric measurements of an anthropomorphic brain phantom were within 3%-5% of actual values. The mask data were used to register images of a brain phantom and of a volunteer's brain, respectively. The rigid transformation that allowed the merging of masks by visual inspection was applied to the 2 sets of SPECT slices to perform the fusion of the data. At the cost of an additional low-cost setup integrated into the gamma-camera gantry, real-time data about the surface of the head were obtained. As in all other surface-based techniques (as opposed to volume-based techniques), this method allows the match of data independently from the dataset of interest and facilitates further registration of data from any other source. The main advantage of this technique compared with other optically based methods is the robustness of the calibration procedure and the compactness of the sensor as a result of the colinearity of the projected beam and the reflected (diffused) beams of the conoscope. Taking into account the experimental nature of this preliminary work, significant improvements in the accuracy and speed of measurements (up to 1000 points/s) are expected.

Immunocytochemical detection of astrocytes in brain slices in combination with Nissl staining.

PubMed

Korzhevskii, D E; Otellin, V A

2005-07-01

The present study was performed to develop a simple and reliable method for the combined staining of specimens to allow the advantages of immunocytochemical detection of astrocytes and assessment of the functional state of neurons by the Nissl method to be assessed simultaneously. The protocol suggested for processing paraffin sections allows preservation of tissue structure at high quality and allows the selective identification of astrocytes with counterstaining of neurons by the Nissl method. The protocol can be used without modification for processing brain specimens from humans and various mammals--except mice and rabbits.

In vivo PET imaging of beta-amyloid deposition in mouse models of Alzheimer's disease with a high specific activity PET imaging agent [(18)F]flutemetamol.

PubMed

Snellman, Anniina; Rokka, Johanna; López-Picón, Francisco R; Eskola, Olli; Salmona, Mario; Forloni, Gianluigi; Scheinin, Mika; Solin, Olof; Rinne, Juha O; Haaparanta-Solin, Merja

2014-01-01

The purpose of the study was to evaluate the applicability of (18) F-labelled amyloid imaging positron emission tomography (PET) agent [ (18) F]flutemetamol to detect changes in brain beta-amyloid (Aβ) deposition in vivo in APP23, Tg2576 and APPswe-PS1dE9 mouse models of Alzheimer's disease. We expected that the high specific activity of [ (18) F]flutemetamol would make it an attractive small animal Aβ imaging agent. [ (18) F]flutemetamol uptake in the mouse brain was evaluated in vivo at 9 to 22 months of age with an Inveon Multimodality PET/CT camera (Siemens Medical Solutions USA, Knoxville, TN, USA). Retention in the frontal cortex (FC) was evaluated by Logan distribution volume ratios (DVR) and FC/cerebellum (CB) ratios during the late washout phase (50 to 60 min). [ (18) F]flutemetamol binding to Aβ was also evaluated in brain slices by in vitro and ex vivo autoradiography. The amount of Aβ in the brain slices was determined with Thioflavin S and anti-Aβ1-40 immunohistochemistry. In APP23 mice, [ (18) F]flutemetamol retention in the FC increased from 9 to 18 months. In younger mice, DVR and FC/CB50-60 were 0.88 (0.81) and 0.88 (0.89) at 9 months (N = 2), and 0.98 (0.93) at 12 months (N = 1), respectively. In older mice, DVR and FC/CB50-60 were 1.16 (1.15) at 15 months (N = 1), 1.13 (1.16) and 1.35 (1.35) at 18 months (N = 2), and 1.05 (1.31) at 21 months (N = 1). In Tg2576 mice, DVR and FC/CB50-60 showed modest increasing trends but also high variability. In APPswe-PS1dE9 mice, DVR and FC/CB50-60 did not increase with age. Thioflavin S and anti-Aβ1-40 positive Aβ deposits were present in all transgenic mice at 19 to 22 months, and they co-localized with [ (18) F]flutemetamol binding in the brain slices examined with in vitro and ex vivo autoradiography. Increased [ (18) F]flutemetamol retention in the brain was detected in old APP23 mice in vivo. However, the high specific activity of [ (18) F]flutemetamol did not provide a notable advantage in Tg2576 and APPswe-PS1dE9 mice compared to the previously evaluated structural analogue [(11)C]PIB. For its practical benefits, [ (18) F]flutemetamol imaging with a suitable mouse model like APP23 is an attractive alternative.

In vivo PET imaging of beta-amyloid deposition in mouse models of Alzheimer's disease with a high specific activity PET imaging agent [18F]flutemetamol

PubMed Central

2014-01-01

Background The purpose of the study was to evaluate the applicability of 18F-labelled amyloid imaging positron emission tomography (PET) agent [18F]flutemetamol to detect changes in brain beta-amyloid (Aβ) deposition in vivo in APP23, Tg2576 and APPswe-PS1dE9 mouse models of Alzheimer's disease. We expected that the high specific activity of [18F]flutemetamol would make it an attractive small animal Aβ imaging agent. Methods [18F]flutemetamol uptake in the mouse brain was evaluated in vivo at 9 to 22 months of age with an Inveon Multimodality PET/CT camera (Siemens Medical Solutions USA, Knoxville, TN, USA). Retention in the frontal cortex (FC) was evaluated by Logan distribution volume ratios (DVR) and FC/cerebellum (CB) ratios during the late washout phase (50 to 60 min). [18F]flutemetamol binding to Aβ was also evaluated in brain slices by in vitro and ex vivo autoradiography. The amount of Aβ in the brain slices was determined with Thioflavin S and anti-Aβ1−40 immunohistochemistry. Results In APP23 mice, [18F]flutemetamol retention in the FC increased from 9 to 18 months. In younger mice, DVR and FC/CB50-60 were 0.88 (0.81) and 0.88 (0.89) at 9 months (N = 2), and 0.98 (0.93) at 12 months (N = 1), respectively. In older mice, DVR and FC/CB50-60 were 1.16 (1.15) at 15 months (N = 1), 1.13 (1.16) and 1.35 (1.35) at 18 months (N = 2), and 1.05 (1.31) at 21 months (N = 1). In Tg2576 mice, DVR and FC/CB50-60 showed modest increasing trends but also high variability. In APPswe-PS1dE9 mice, DVR and FC/CB50-60 did not increase with age. Thioflavin S and anti-Aβ1−40 positive Aβ deposits were present in all transgenic mice at 19 to 22 months, and they co-localized with [18F]flutemetamol binding in the brain slices examined with in vitro and ex vivo autoradiography. Conclusions Increased [18F]flutemetamol retention in the brain was detected in old APP23 mice in vivo. However, the high specific activity of [18F]flutemetamol did not provide a notable advantage in Tg2576 and APPswe-PS1dE9 mice compared to the previously evaluated structural analogue [11C]PIB. For its practical benefits, [18F]flutemetamol imaging with a suitable mouse model like APP23 is an attractive alternative. PMID:25977876

Photon Entanglement Through Brain Tissue.

PubMed

Shi, Lingyan; Galvez, Enrique J; Alfano, Robert R

2016-12-20

Photon entanglement, the cornerstone of quantum correlations, provides a level of coherence that is not present in classical correlations. Harnessing it by study of its passage through organic matter may offer new possibilities for medical diagnosis technique. In this work, we study the preservation of photon entanglement in polarization, created by spontaneous parametric down-conversion, after one entangled photon propagates through multiphoton-scattering brain tissue slices with different thickness. The Tangle-Entropy (TS) plots show the strong preservation of entanglement of photons propagating in brain tissue. By spatially filtering the ballistic scattering of an entangled photon, we find that its polarization entanglement is preserved and non-locally correlated with its twin in the TS plots. The degree of entanglement correlates better with structure and water content than with sample thickness.

Photon Entanglement Through Brain Tissue

NASA Astrophysics Data System (ADS)

Shi, Lingyan; Galvez, Enrique J.; Alfano, Robert R.

2016-12-01

Photon entanglement, the cornerstone of quantum correlations, provides a level of coherence that is not present in classical correlations. Harnessing it by study of its passage through organic matter may offer new possibilities for medical diagnosis technique. In this work, we study the preservation of photon entanglement in polarization, created by spontaneous parametric down-conversion, after one entangled photon propagates through multiphoton-scattering brain tissue slices with different thickness. The Tangle-Entropy (TS) plots show the strong preservation of entanglement of photons propagating in brain tissue. By spatially filtering the ballistic scattering of an entangled photon, we find that its polarization entanglement is preserved and non-locally correlated with its twin in the TS plots. The degree of entanglement correlates better with structure and water content than with sample thickness.

Interactive brain shift compensation using GPU based programming

NASA Astrophysics Data System (ADS)

van der Steen, Sander; Noordmans, Herke Jan; Verdaasdonk, Rudolf

2009-02-01

Processing large images files or real-time video streams requires intense computational power. Driven by the gaming industry, the processing power of graphic process units (GPUs) has increased significantly. With the pixel shader model 4.0 the GPU can be used for image processing 10x faster than the CPU. Dedicated software was developed to deform 3D MR and CT image sets for real-time brain shift correction during navigated neurosurgery using landmarks or cortical surface traces defined by the navigation pointer. Feedback was given using orthogonal slices and an interactively raytraced 3D brain image. GPU based programming enables real-time processing of high definition image datasets and various applications can be developed in medicine, optics and image sciences.

Brain tissue water content in patients with idiopathic normal pressure hydrocephalus.

PubMed

Aygok, G; Marmarou, A; Fatouros, P; Young, H

2006-01-01

Relatively little is known regarding the water content of brain tissue in idiopathic normal-pressure hydrocephalus (NPH) patients. The objective of our study was to determine absolute water content non-invasively in hydrocephalic patients, particularly in the anterior and posterior ventricular horns and in the periventricular white matter. Ten patients who were diagnosed and treated for idiopathic NPH in our clinic were selected for study. Magnetic resonance imaging (MRI) techniques were used to obtain anatomical image slices for quantitative brain water measurements. Apparent diffusion coefficient measures were also extracted from regions of interest. To our knowledge, this is the first study to confirm that periventricular lucency seen on MRI represents increased water content in the extracellular space that is markedly elevated prior to shunting.

Caffeine, Adenosine Receptors and Estrogen in Toxin Models of Parkinson’s Disease

DTIC Science & Technology

2005-10-01

right). Adjacent coronal brain sections were processed for A2A receptor immunohistochemsitry (B) with a HRP-coupled secondary antibody yielding a...declines steadily with increasing intake of caffeine or of coffee (but not decaffeinated coffee). The mechanisms that underlie this epidemiological...ad Sju - 5261.[7 of decaffeinated coffee was not associated with an Furthermore. A2A knockout mice (lacking function- altered risk of PD). clearly

Brain Region-Specific Trafficking of the Dopamine Transporter

PubMed Central

Block, Ethan R.; Nuttle, Jacob; Balcita-Pedicino, Judith Joyce; Caltagarone, John; Watkins, Simon C.

2015-01-01

The dopamine (DA) transporter (DAT) controls dopaminergic neurotransmission by removing extracellular DA. Although DA reuptake is proposed to be regulated by DAT traffic to and from the cell surface, the membrane trafficking system involved in the endocytic cycling of DAT in the intact mammalian brain has not been characterized. Hence, we performed immunolabeling and quantitative analysis of the subcellular and regional distribution of DAT using the transgenic knock-in mouse expressing hemagglutinin (HA) epitope-tagged DAT (HA-DAT) and by using a combination of electron microscopy and a novel method for immunofluorescence labeling of HA-DAT in acute sagittal brain slices. Both approaches demonstrated that, in midbrain somatodendritic regions, HA-DAT was present in the plasma membrane, endoplasmic reticulum, and Golgi complex, with a small fraction in early and recycling endosomes and an even smaller fraction in late endosomes and lysosomes. In the striatum and in axonal tracts between the midbrain and striatum, HA-DAT was detected predominantly in the plasma membrane, and quantitative analysis revealed increased DAT density in striatal compared with midbrain plasma membranes. Endosomes were strikingly rare and lysosomes were absent in striatal axons, in which there was little intracellular HA-DAT. Acute administration of amphetamine in vivo (60 min) or to slices ex vivo (10–60 min) did not result in detectable changes in DAT distribution. Altogether, these data provide evidence for regional differences in DAT plasma membrane targeting and retention and suggest a surprisingly low level of endocytic trafficking of DAT in the striatum along with limited DAT endocytic activity in somatodendritic areas. SIGNIFICANCE STATEMENT The dopamine transporter (DAT) is the key regulator of the dopamine neurotransmission in the CNS. In the present study, we developed a new approach for studying DAT localization and dynamics in intact neurons in acute sagittal brain slices from the knock-in mouse expressing epitope-tagged DAT. For the first time, the fluorescence imaging analysis of DAT was combined with the immunogold labeling of DAT and quantitative electron microscopy. In contrast to numerous studies of DAT trafficking in heterologous expression systems and dissociated cultured neurons, studies in intact neurons revealed a surprisingly low amount of endocytic trafficking of DAT at steady state and after acute amphetamine treatment and suggested that non-vesicular transport could be the main mechanism establishing DAT distribution within the dopaminergic neuron. PMID:26377471

Do Recent Advances in MR Technologies Contribute to Better Gamma Knife Radiosurgery Treatment Results for Brain Metastases?

PubMed

Hayashi, M; Yamamoto, M; Nishimura, C; Satoh, H

2007-10-31

The detection of intracerebral lesions has improved greatly with advancements in MR imaging, especially the greater sensitivity of the 1.5 Tesla unit versus the older 1.0 Tesla unit. We aimed to determine whether improvements in MR imaging have actually improved diagnostic capabilities and treatment outcomes in gamma knife radiosurgery (GKRS) for brain metastases (METs). Ours was a retrospective study of a consecutive series of 1179 patients (441 females, 738 males, mean age: 63 years, range: 19-92 years) with brain METs who underwent GKRS from 1998 to 2004. Our treatment policy was to irradiate all lesions visible on MR images during a single GKRS session. Mean and median tumor numbers were seven and three (range; 1-74). The 1179 patients were divided into two groups: a 1.0 T-group of 660 patients examined using a 1.0 Tesla MR unit before August,2002, and a 1.5 T-group of 519 examined using a 1.5 Tesla MR unit after September 2002. In the 1.5 T-group, lesion volumes as small as 0.004 cc were detected with a 5 mm slice thickness. The corresponding lesion size was 0.013 cc in the 1.0 T-group. One or more lesions invisible on a 5 mm slice study were additionally detected on a 2 mm slice study in 47.8% of patients in the 1.0 T-group and 25.2% in the 1.5 T-group (p<.0001). The median survival time (MST) in the 1.5 T-group was significantly longer than that in the 1.0 T-group (8.4 vs. 6.3 months, p=.0004). Due to biases in patient numbers between the two groups, we analyzed subgroups with KPS of 80% or better, no neurological deficits, stable primary tumors, lung cancer, tumor numbers of four or less and tumor volumes of 10.0 cc or smaller. In every subgroup analysis, the MSTs of the 1.5-Tesla group were significantly longer than those of the 1.0-Tesla group. The prognosis of a cancer patient is undoubtedly influenced by multiple factors. Nevertheless, we conclude that application of the 1.5 Tesla MR unit has had a favorable impact on diagnosis and GKRS treatment results in patients with brain METs.

A testbed to explore the optimal electrical stimulation parameters for suppressing inter-ictal spikes in human hippocampal slices.

PubMed

Min-Chi Hsiao; Pen-Ning Yu; Dong Song; Liu, Charles Y; Heck, Christi N; Millett, David; Berger, Theodore W

2014-01-01

New interventions using neuromodulatory devices such as vagus nerve stimulation, deep brain stimulation and responsive neurostimulation are available or under study for the treatment of refractory epilepsy. Since the actual mechanisms of the onset and termination of the seizure are still unclear, most researchers or clinicians determine the optimal stimulation parameters through trial-and-error procedures. It is necessary to further explore what types of electrical stimulation parameters (these may include stimulation frequency, amplitude, duration, interval pattern, and location) constitute a set of optimal stimulation paradigms to suppress seizures. In a previous study, we developed an in vitro epilepsy model using hippocampal slices from patients suffering from mesial temporal lobe epilepsy. Using a planar multi-electrode array system, inter-ictal activity from human hippocampal slices was consistently recorded. In this study, we have further transferred this in vitro seizure model to a testbed for exploring the possible neurostimulation paradigms to inhibit inter-ictal spikes. The methodology used to collect the electrophysiological data, the approach to apply different electrical stimulation parameters to the slices are provided in this paper. The results show that this experimental testbed will provide a platform for testing the optimal stimulation parameters of seizure cessation. We expect this testbed will expedite the process for identifying the most effective parameters, and may ultimately be used to guide programming of new stimulating paradigms for neuromodulatory devices.

Development and Assessment of a New 3D Neuroanatomy Teaching Tool for MRI Training

ERIC Educational Resources Information Center

Drapkin, Zachary A.; Lindgren, Kristen A.; Lopez, Michael J.; Stabio, Maureen E.

2015-01-01

A computerized three-dimensional (3D) neuroanatomy teaching tool was developed for training medical students to identify subcortical structures on a magnetic resonance imaging (MRI) series of the human brain. This program allows the user to transition rapidly between two-dimensional (2D) MRI slices, 3D object composites, and a combined model in…

Anatomical Distribution of Lipids in Human Brain Cortex by Imaging Mass Spectrometry

NASA Astrophysics Data System (ADS)

Veloso, Antonio; Astigarraga, Egoitz; Barreda-Gómez, Gabriel; Manuel, Iván; Ferrer, Isidro; Teresa Giralt, María; Ochoa, Begoña; Fresnedo, Olatz; Rodríguez-Puertas, Rafael; Fernández, José A.

2011-02-01

Molecular mass images of tissues will be biased if differences in the physicochemical properties of the microenvironment affect the intensity of the spectra. To address this issue, we have performed—by means of MALDI-TOF mass spectrometry—imaging on slices and lipidomic analysis in extracts of frontal cortex, both from the same postmortem tissue samples of human brain. An external calibration was used to achieve a mass accuracy of 10 ppm (1 σ) in the spectra of the extracts, although the final assignment was based on a comparison with previously reported species. The spectra recorded directly from tissue slices (imaging) show excellent s/n ratios, almost comparable to those obtained from the extracts. In addition, they retain the information about the anatomical distribution of the molecular species present in autopsied frozen tissue. Further comparison between the spectra from lipid extracts devoid of proteins and those recorded directly from the tissue unambiguously show that the differences in lipid composition between gray and white matter observed in the mass images are not an artifact due to microenvironmental influences of each anatomical area on the signal intensity, but real variations in the lipid composition.

Interaction of a vasopressin antagonist with vasopressin receptors in the septum of the rat brain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorsa, D.M.; Brot, M.D.; Shewey, L.M.

1988-01-01

The ability of d(CH2)5-Tyr(Me)-arginine-8-vasopressin, an antagonist of peripheral pressoric (V1-type) vasopressin receptors, to label vasopressin binding sites in the septum of the rat brain was evaluated. Using crude membrane preparations from the septum, /sup 3/H-arginine-8-vasopressin (AVP) specifically labels a single class of binding sites with a Kd of 2.9 nM and maximum binding site concentration of 19.8 fmole/mg protein. /sup 3/H-Antag also labels a single class of membrane sites but with higher affinity (Kd = 0.47 nM) and lower capacity (10.1 fmole/mg protein) than /sup 3/H-AVP. The rank order of potency of various competitor peptides for /sup 3/H-AVP and /supmore » 3/H-Antag binding was similar. Oxytocin was 100-1,000 fold less potent than AVP in competing for binding with both ligands. /sup 3/H-AVP and /sup 3/H-Antag showed similar labeling patterns when incubated with septal tissue slices. Unlabeled Antag also effectively antagonized vasopressin-stimulated phosphatidylinositol hydrolysis in septal tissue slices.« less

[A cross-correlational analysis of the background neuronal pulse trains in surviving slices of the guinea pig neocortex].

PubMed

Bortnik, A T; Iakupova, L P

1991-01-01

Cross-correlation analysis of interdependence of the background spike activity was carried out for pairs of adjacent neurons simultaneously recorded in the incubated slices of the neocortex of guinea-pig. Statistical correlation of spike discharges was detected in 16 out of 26 recorded pairs of the neurons. Significant correlation was observed mainly in the range of +/- 100 ms from the null point. Cross-correlation had symmetric or asymmetric maxima up to 150 ms long and negative shifts up to 200 ms long. More complex positive-negative types of cross-correlations were also obtained. The data were compared to those known from other authors for the intact brain. The contribution of intrinsic intracortical interactions and extrinsic afferent influences in these correlations of activity is discussed.

Changes in spontaneous brain activity in early Parkinson's disease.

PubMed

Yang, Hong; Zhou, Xiaohong Joe; Zhang, Min-Ming; Zheng, Xu-Ning; Zhao, Yi-Lei; Wang, Jue

2013-08-09

Resting state brain activity can provide valuable insights into the pathophysiology of Parkinson's disease (PD). The purpose of the present study was (a) to investigate abnormal spontaneous neuronal activity in early PD patients using resting-state functional MRI (fMRI) with a regional homogeneity (ReHo) method and (b) to demonstrate the potential of using changes in abnormal spontaneous neuronal activity for monitoring the progression of PD during its early stages. Seventeen early PD patients were assessed with the Unified Parkinson's Disease Rating Scale (UPDRS), the Hoehn and Yahr disability scale and the Mini-mental State Examination (MMSE) were compared with seventeen gender- and age-matched healthy controls. All subjects underwent MRI scans using a 1.5T General Electric Signa Excite II scanner. The MRI scan protocol included whole-brain volumetric imaging using a 3D inversion recovery prepared (IR-Prep) fast spoiled gradient-echo pulse sequence and 2D multi-slice (22 axial slices covering the whole brain) resting-state fMRI using an echo planar imaging (EPI) sequence. Images were analyzed in SPM5 together with a ReHo algorithm using the in-house software program REST. A corrected threshold of p<0.05 was determined by AlphaSim and used in statistical analysis. Compared with the healthy controls, the early PD group showed significantly increased ReHo in a number of brain regions, including the left cerebellum, left parietal lobe, right middle temporal lobe, right sub-thalamic nucleus areas, right superior frontal gyrus, middle frontal gyrus (MFG), right inferior parietal lobe (IPL), right precuneus lobe, left MFG and left IPL. Additionally, significantly reduced ReHo was also observed in the early PD patients in the following brain regions: the left putamen, left inferior frontal gyrus, right hippocampus, right anterior cingulum, and bilateral lingual gyrus. Moreover, in PD patients, ReHo in the left putamen was negatively correlated with the UPDRS scores (r=-0.69). These results indicate that the abnormal resting state spontaneous brain activity associated with patients with early PD can be revealed by Reho analysis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Effect of chronic treatment with the GABA transaminase inhibitors gamma-vinyl GABA and ethanolamine O-sulphate on the in vitro GABA release from rat hippocampus.

PubMed

Qume, M; Fowler, L J

1997-10-01

1. The effects of 2, 8 and 21 day oral treatment with the specific gamma-aminobutyric acid transaminase (GABA-T) inhibitors gamma-vinyl GABA (GVG) and ethanolamine O-sulphate (EOS) on brain GABA levels, GABA-T activity, and basal and stimulated GABA release from rat cross-chopped brain hippocampal slices was investigated. 2. Treatment with GABA-T inhibitors lead to a reduction in brain GABA-T activity by 65-80% compared with control values, with a concomitant increase in brain GABA content of 40-100%. 3. Basal hippocampal GABA release was increased to 250-450% of control levels following inhibition of GABA-T activity. No Ca2+ dependence was observed in either control or treated tissues. 4. GVG and EOS administration led to a significant elevation in the potassium stimulated release of GABA from cross-chopped hippocampal slices compared with that of controls. Although stimulated GABA release from control tissues was decreased in the presence of a low Ca2+ medium, GVG and EOS treatment abolished this Ca2+ dependency. 5. GABA compartmentalization, Na+ and Cl- coupled GABA uptake carriers and glial release may provide explanations for the loss of the Ca2+ dependency of stimulated GABA release observed following GVG and EOS treatment. 6. Administration of GABA-T inhibitors led to increases in both basal and stimulated hippocampal GABA release. However, it is not clear which is the most important factor in the anticonvulsant activity of these drugs, the increased GABA content 'leaking' out of neurones and glia leading to widespread inhibition, or the increase in stimulated GABA release which may occur following depolarization caused by an epileptic discharge.

Effect of chronic treatment with the GABA transaminase inhibitors γ-vinyl GABA and ethanolamine O-sulphate on the in vitro GABA release from rat hippocampus

PubMed Central

Qume, M; Fowler, L J

1997-01-01

The effects of 2, 8 and 21 day oral treatment with the specific γ-aminobutyric acid transaminase (GABA-T) inhibitors γ-vinyl GABA (GVG) and ethanolamine O-sulphate (EOS) on brain GABA levels, GABA-T activity, and basal and stimulated GABA release from rat cross-chopped brain hippocampal slices was investigated. Treatment with GABA-T inhibitors lead to a reduction in brain GABA-T activity by 65–80% compared with control values, with a concomitant increase in brain GABA content of 40–100%. Basal hippocampal GABA release was increased to 250–450% of control levels following inhibition of GABA-T activity. No Ca2+ dependence was observed in either control or treated tissues. GVG and EOS administration led to a significant elevation in the potassium stimulated release of GABA from cross-chopped hippocampal slices compared with that of controls. Although stimulated GABA release from control tissues was decreased in the presence of a low Ca2+ medium, GVG and EOS treatment abolished this Ca2+ dependency. GABA compartmentalization, Na+ and Cl− coupled GABA uptake carriers and glial release may provide explanations for the loss of the Ca2+ dependency of stimulated GABA release observed following GVG and EOS treatment. Administration of GABA-T inhibitors led to increases in both basal and stimulated hippocampal GABA release. However, it is not clear which is the most important factor in the anticonvulsant activity of these drugs, the increased GABA content ‘leaking' out of neurones and glia leading to widespread inhibition, or the increase in stimulated GABA release which may occur following depolarization caused by an epileptic discharge. PMID:9351512

Two cell circuits of oriented adult hippocampal neurons on self-assembled monolayers for use in the study of neuronal communication in a defined system.

PubMed

Edwards, Darin; Stancescu, Maria; Molnar, Peter; Hickman, James J

2013-08-21

In this study, we demonstrate the directed formation of small circuits of electrically active, synaptically connected neurons derived from the hippocampus of adult rats through the use of engineered chemically modified culture surfaces that orient the polarity of the neuronal processes. Although synaptogenesis, synaptic communication, synaptic plasticity, and brain disease pathophysiology can be studied using brain slice or dissociated embryonic neuronal culture systems, the complex elements found in neuronal synapses makes specific studies difficult in these random cultures. The study of synaptic transmission in mature adult neurons and factors affecting synaptic transmission are generally studied in organotypic cultures, in brain slices, or in vivo. However, engineered neuronal networks would allow these studies to be performed instead on simple functional neuronal circuits derived from adult brain tissue. Photolithographic patterned self-assembled monolayers (SAMs) were used to create the two-cell "bidirectional polarity" circuit patterns. This pattern consisted of a cell permissive SAM, N-1[3-(trimethoxysilyl)propyl] diethylenetriamine (DETA), and was composed of two 25 μm somal adhesion sites connected with 5 μm lines acting as surface cues for guided axonal and dendritic regeneration. Surrounding the DETA pattern was a background of a non-cell-permissive poly(ethylene glycol) (PEG) SAM. Adult hippocampal neurons were first cultured on coverslips coated with DETA monolayers and were later passaged onto the PEG-DETA bidirectional polarity patterns in serum-free medium. These neurons followed surface cues, attaching and regenerating only along the DETA substrate to form small engineered neuronal circuits. These circuits were stable for more than 21 days in vitro (DIV), during which synaptic connectivity was evaluated using basic electrophysiological methods.

Independent Epileptiform Discharge Patterns in the Olfactory and Limbic Areas of the In Vitro Isolated Guinea Pig Brain During 4-Aminopyridine Treatment

PubMed Central

Carriero, Giovanni; Uva, Laura; Gnatkovsky, Vadym; Avoli, Massimo; de Curtis, Marco

2016-01-01

In vitro studies performed on brain slices demonstrate that the potassium channel blocker 4-aminopyridine (4AP, 50 μM) discloses electrographic seizure activity and interictal discharges. These epileptiform patterns have been further analyzed here in a isolated whole guinea pig brain in vitro by using field potential recordings in olfactory and limbic structures. In 8 of 13 experiments runs of fast oscillatory activity (fast runs, FRs) in the piriform cortex (PC) propagated to the lateral entorhinal cortex (EC), hippocampus and occasionally to the medial EC. Early and late FRs were asynchronous in the hemispheres showed different duration [1.78 ± 0.51 and 27.95 ± 4.55 (SD) s, respectively], frequency of occurrence (1.82 ± 0.49 and 34.16 ± 6.03 s) and frequency content (20–40 vs. 40–60 Hz). Preictal spikes independent from the FRs appeared in the hippocampus/EC and developed into ictal-like discharges that did not propagate to the PC. Ictal-like activity consisted of fast activity with onset either in the hippocampus (n = 6) or in the mEC (n = 2), followed by irregular spiking and sequences of diffusely synchronous bursts. Perfusion of the N-methyl-D-aspartate receptor antagonist 2-amino-5-phosphonopentanoic acid (100 μM) did not prevent FRs, increased the duration of limbic ictal-like discharges and favored their propagation to olfactory structures. The AMPA receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (50 μM) blocked ictal-like events and reduced FRs. In conclusion, 4AP-induced epileptiform activities are asynchronous and independent in olfactory and hippocampal-entorhinal regions. Epileptiform discharges in the isolated guinea pig brain show different pharmacological properties compared with rodent in vitro slices. PMID:20220076

Improvement of tactile perception and enhancement of cortical excitability through intermittent theta burst rTMS over human primary somatosensory cortex.

PubMed

Ragert, Patrick; Franzkowiak, Stephanie; Schwenkreis, Peter; Tegenthoff, Martin; Dinse, Hubert R

2008-01-01

Adopting the patterns of theta burst stimulation (TBS) used in brain-slice preparations, a novel and rapid method of conditioning the human brain has recently been introduced. Using short bursts of high-frequency (50 Hz) repetitive transcranial magnetic stimulation (rTMS) has been shown to induce lasting changes in brain physiology of the motor cortex. In the present study, we tested whether a few minutes of intermittent theta burst stimulation (iTBS) over left primary somatosensory cortex (SI) evokes excitability changes within the stimulated brain area and whether such changes are accompanied by changes in tactile discrimination behavior. As a measure of altered perception we assessed tactile discrimination thresholds on the right and left index fingers (d2) before and after iTBS. We found an improved discrimination performance on the right d2 that was present for at least 30 min after termination of iTBS. Similar improvements were found for the ring finger, while left d2 remained unaffected in all cases. As a control, iTBS over the tibialis anterior muscle representation within primary motor cortex had no effects on tactile discrimination. Recording somatosensory evoked potentials over left SI after median nerve stimulation revealed a reduction in paired-pulse inhibition after iTBS that was associated but not correlated with improved discrimination performance. No excitability changes could be found for SI contralateral to iTBS. Testing the performance of simple motor tasks revealed no alterations after iTBS was applied over left SI. Our results demonstrate that iTBS protocols resembling those used in slice preparations for the induction of long-term potentiation are also effective in driving lasting improvements of the perception of touch in human subjects together with an enhancement of cortical excitability.

Organotypic cultures as tools for testing neuroactive drugs - link between in-vitro and in-vivo experiments.

PubMed

Drexler, B; Hentschke, H; Antkowiak, B; Grasshoff, C

2010-01-01

The development of neuroactive drugs is a time consuming procedure. Candidate drugs must be run through a battery of tests, including receptor studies and behavioural tests on animals. As a rule, numerous substances with promising properties as assessed in receptor studies must be eliminated from the development pipeline in advanced test phases because of unforeseen problems like intolerable side-effects or unsatisfactory performance in the whole organism. Clearly, test systems of intermediate complexity would alleviate this inefficiency. In this review, we propose cultured organotypic brain slices as model systems that could bridge the 'interpolation gap' between receptors and the brain, with a focus on the development of new general anaesthetics with lesser side effects. General anaesthesia is based on the modulation of neurotransmitter receptors and other conductances located on neurons in diverse brain regions, including cerebral cortex and spinal cord. It is well known that different components of general anaesthesia, e.g. hypnosis and immobility, are produced by the depression of neuronal activity in distinct brain regions. The ventral horn of the spinal cord is an important structure for the induction of immobility. Thus, the potentially immobilizing effects of a newly designed drug can be estimated from its depressant effect on neuronal network activity in cultured spinal slices. A drug's sedative and hypnotic potential can be examined in cortical cultures. Combined with genetically engineered mice, this approach can point to receptor subtypes most relevant to the drug's intended net effect and in return can help in the design of more selective drugs. In conclusion, the use of organotypic cultures permits predictions of neuroactive properties of newly designed drugs on an intermediate level, and should therefore open up avenues for a more creative and economic drug development process.

A comparison of the apoptotic effect of Delta(9)-tetrahydrocannabinol in the neonatal and adult rat cerebral cortex.

PubMed

Downer, Eric J; Gowran, Aoife; Campbell, Veronica A

2007-10-17

The maternal use of cannabis during pregnancy results in a number of cognitive deficits in the offspring that persist into adulthood. The endocannabinoid system has a role to play in neurodevelopmental processes such as neurogenesis, migration and synaptogenesis. However, exposure to phytocannabinoids, such as Delta(9)-tetrahydrocannabinol, during gestation may interfere with these events to cause abnormal patterns of neuronal wiring and subsequent cognitive impairments. Aberrant cell death evoked by Delta(9)-tetrahydrocannabinol may also contribute to cognitive deficits and in cultured neurones Delta(9)-tetrahydrocannabinol induces apoptosis via the CB(1) cannabinoid receptor. In this study we report that Delta(9)-tetrahydrocannabinol (5-50 microM) activates the stress-activated protein kinase, c-jun N-terminal kinase, and the pro-apoptotic protease, caspase-3, in in vitro cerebral cortical slices obtained from the neonatal rat brain. The proclivity of Delta(9)-tetrahydrocannabinol to impact on these pro-apoptotic signalling molecules was not observed in in vitro cortical slices obtained from the adult rat brain. In vivo, subcutaneous administration of Delta(9)-tetrahydrocannabinol (1-30 mg/kg) activated c-jun N-terminal kinase, caspase-3 and cathepsin-D, and induced DNA fragmentation in the cerebral cortex of neonatal rats. In contrast, in vivo administration of Delta(9)-tetrahydrocannabinol to adult rats was not associated with the apoptotic pathway in the cerebral cortex. The data provide evidence which supports the hypothesis that the neonatal rat brain is more vulnerable to the neurotoxic influence of Delta(9)-tetrahydrocannabinol, suggesting that the cognitive deficits that are observed in humans exposed to marijuana during gestation may be due, in part, to abnormal engagement of the apoptotic cascade during brain development.