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Sample records for experimental functional neurosurgery

  1. Functional neurosurgery. The modulation of neural and mind circuits.

    PubMed

    Al-Otaibi, Faisal; Al-Khairallah, Thamer

    2012-01-01

    Different complex neuroanatomical and neurochemical circuits regulate a variety of neuronal behaviors and brain functions. Any disturbance in these circuits can generate functional disorders such as movement disorders, epilepsy, pain, memory disorders, and psychiatric disorders. Functional neurosurgery aims to restore these functions, either by removing or isolating the abnormally behaving neurons or by modulating the disturbed circuits. Neuromodulation is a fast-growing field, powered by the recent advances in neuroimaging and technology. Here, we discuss recent advances and new horizons in functional neurosurgery.

  2. Experimental and clinical standards, and evolution of lasers in neurosurgery.

    PubMed

    Devaux, B C; Roux, F X

    1996-01-01

    From initial experiments of ruby, argon and CO2 lasers on the nervous system so far, dramatic progress was made in delivery systems technology as well as in knowledge of laser-tissue interaction effects and hazards through various animal experiments and clinical experience. Most surgical effects of laser light on neural tissue and the central nervous system (CNS) are thermal lesions. Haemostasis, cutting and vaporization depend on laser emission parameters--wavelength, fluence and mode--and on the exposed tissues optical and thermal properties--water and haemoglobin content, thermal conductivity and specific heat. CO2 and Nd-YAG lasers have today a large place in the neurosurgical armamentarium, while new laser sources such as high power diode lasers will have one in the near future. Current applications of these lasers derive from their respective characteristics, and include CNS tumour and vascular malformation surgery, and stereotactic neurosurgery. Intracranial, spinal cord and intra-orbital meningiomas are the best lesions for laser use for haemostasis, dissection and tissue vaporization. Resection of acoustic neuromas, pituitary tumours, spinal cord neuromas, intracerebral gliomas and metastases may also benefit from lasers as accurate, haemostatic, non-contact instruments which reduce surgical trauma to the brain and eloquent structures such as brain stem and cranial nerves. Coagulative lasers (1.06 microns and 1.32 microns Nd-YAG, argon, or diode laser) will find an application for arteriovenous malformations and cavernomas. Any fiberoptic-guided laser will find a use during stereotactic neurosurgical procedures, including image-guided resection of tumours and vascular malformations and endoscopic tumour resection and cysts or entry into a ventricle. Besides these routine applications of lasers, laser interstitial thermotherapy (LITT) and photodynamic therapy (PDT) of brain tumours are still in the experimental stage. The choice of a laser in a

  3. Pediatric Epilepsy: Neurology, Functional Imaging, and Neurosurgery.

    PubMed

    Mountz, James M; Patterson, Christina M; Tamber, Mandeep S

    2017-03-01

    In this chapter we provide a comprehensive review of the current role that functional imaging can have in the care of the pediatric epilepsy patient from the perspective of the epilepsy neurologist and the epilepsy neurosurgeon. In the neurology section, the diagnosis and classification of epilepsy adapted by the International League Against Epilepsy as well as the etiology and incidence of the disease is presented. The neuroimaging section describes how advanced nuclear medicine imaging methods can be synergized to provide a maximum opportunity to localize an epileptogenic focus. This section described the value of FDG-PET and regional cerebral blood flow SPECT in the identification of an epileptogenic focus. The imaging section also emphasizes the importance on developing a dedicated epilepsy management team, comprised of an epilepsy imaging specialist, epilepsy neurologist and epilepsy neurosurgeon, to provide the maximum benefit to each child with epilepsy. An emphasis is placed on preparation for ictal SPECT injection procedures, including the critical role of an automated injector well as the use of state-of-the-art dedicated nuclear medicine imaging and analysis protocols to correctly localize the epileptogenic focus location. In the final section, surgical options, approaches and expected outcomes for the different classes of epilepsy is presented.

  4. Numerical simulations of clinical focused ultrasound functional neurosurgery

    PubMed Central

    Pulkkinen, Aki; Werner, Beat; Martin, Ernst; Hynynen, Kullervo

    2014-01-01

    A computational model utilizing grid and finite difference methods was developed to simulate focused ultrasound functional neurosurgery interventions. The model couples the propagation of ultrasound in fluids (soft tissues) and solids (skull) with acoustic and visco-elastic wave equations. The computational model was applied to simulate clinical focused ultrasound functional neurosurgery treatments performed in patients suffering from therapy resistant chronic neuropathic pain. Datasets of five patients were used to derive the treatment geometry. Eight sonications performed in the treatments were then simulated with the developed model. Computations were performed by driving the simulated phased array ultrasound transducer with the acoustic parameters used in the treatments. Resulting focal temperatures and size of the thermal foci were compared quantitatively, in addition to qualitative inspection of the simulated pressure and temperature fields. This study found that the computational model and the simulation parameters predicted an average of 24 ± 13 % lower focal temperature elevations than observed in the treatments. The size of the simulated thermal focus was found to be 40 ± 13 % smaller in the anterior–posterior direction and 22 ± 14% smaller in the inferior–superior direction than in the treatments. The location of the simulated thermal focus was off from the prescribed target by 0.3 ± 0.1 mm, while the peak focal temperature elevation observed in the measurements was off by 1.6 ± 0.6 mm. Although the results of the simulations suggest that there could be some inaccuracies in either the tissue parameters used, or in the simulation methods, the simulations were able to predict the focal spot locations and temperature elevations adequately for initial treatment planning performed to assess, for example, the feasibility of sonication. The accuracy of the simulations could be improved if more precise ultrasound tissue properties (especially of the

  5. Numerical simulations of clinical focused ultrasound functional neurosurgery

    NASA Astrophysics Data System (ADS)

    Pulkkinen, Aki; Werner, Beat; Martin, Ernst; Hynynen, Kullervo

    2014-04-01

    A computational model utilizing grid and finite difference methods were developed to simulate focused ultrasound functional neurosurgery interventions. The model couples the propagation of ultrasound in fluids (soft tissues) and solids (skull) with acoustic and visco-elastic wave equations. The computational model was applied to simulate clinical focused ultrasound functional neurosurgery treatments performed in patients suffering from therapy resistant chronic neuropathic pain. Datasets of five patients were used to derive the treatment geometry. Eight sonications performed in the treatments were then simulated with the developed model. Computations were performed by driving the simulated phased array ultrasound transducer with the acoustic parameters used in the treatments. Resulting focal temperatures and size of the thermal foci were compared quantitatively, in addition to qualitative inspection of the simulated pressure and temperature fields. This study found that the computational model and the simulation parameters predicted an average of 24 ± 13% lower focal temperature elevations than observed in the treatments. The size of the simulated thermal focus was found to be 40 ± 13% smaller in the anterior-posterior direction and 22 ± 14% smaller in the inferior-superior direction than in the treatments. The location of the simulated thermal focus was off from the prescribed target by 0.3 ± 0.1 mm, while the peak focal temperature elevation observed in the measurements was off by 1.6 ± 0.6 mm. Although the results of the simulations suggest that there could be some inaccuracies in either the tissue parameters used, or in the simulation methods, the simulations were able to predict the focal spot locations and temperature elevations adequately for initial treatment planning performed to assess, for example, the feasibility of sonication. The accuracy of the simulations could be improved if more precise ultrasound tissue properties (especially of the

  6. Trends and importance of radiosurgery for the development of functional neurosurgery

    PubMed Central

    Kondziolka, Douglas; Flickinger, John C.; Niranjan, Ajay; Lunsford, L. Dade

    2012-01-01

    Functional neurosurgery includes surgery conducted to ablate, augment, or modulate targets that lead to improvement in neurological function or behavior. Surgical approaches for this purpose include destructive lesioning with different mechanical or biologic agents or energy sources, non-destructive electrical modulation, and cellular or chemical augmentation. Our purpose was to review the role of stereotactic radiosurgery used for functional indications and to discuss future applications and potential techniques. Imaging and neurophysiological research will enable surgeons to consider new targets and circuits that may be clinically important. Radiosurgery is one minimal access approach to those targets. PMID:22826808

  7. Functional connectivity networks for preoperative brain mapping in neurosurgery.

    PubMed

    Hart, Michael G; Price, Stephen J; Suckling, John

    2016-08-26

    OBJECTIVE Resection of focal brain lesions involves maximizing the resection while preserving brain function. Mapping brain function has entered a new era focusing on distributed connectivity networks at "rest," that is, in the absence of a specific task or stimulus, requiring minimal participant engagement. Central to this frame shift has been the development of methods for the rapid assessment of whole-brain connectivity with functional MRI (fMRI) involving blood oxygenation level-dependent imaging. The authors appraised the feasibility of fMRI-based mapping of a repertoire of functional connectivity networks in neurosurgical patients with focal lesions and the potential benefits of resting-state connectivity mapping for surgical planning. METHODS Resting-state fMRI sequences with a 3-T scanner and multiecho echo-planar imaging coupled to independent component analysis were acquired preoperatively from 5 study participants who had a right temporoparietooccipital glioblastoma. Seed-based functional connectivity analysis was performed with InstaCorr. Network identification focused on 7 major functional connectivity networks described in the literature and a putative language network centered on Broca's area. RESULTS All 8 functional connectivity networks were identified in each participant. Tumor-related topological changes to the default mode network were observed in all participants. In addition, each participant had at least 1 other abnormal network, and each network was abnormal in at least 1 participant. Individual patterns of network irregularities were identified with a qualitative approach and included local displacement due to mass effect, loss of a functional network component, and recruitment of new regions. CONCLUSIONS Resting-state fMRI can reliably and rapidly detect common functional connectivity networks in patients with glioblastoma and also has sufficient sensitivity for identifying patterns of network alterations. Mapping of functional

  8. From Structure to Circuits: The Contribution of MEG Connectivity Studies to Functional Neurosurgery

    PubMed Central

    Pang, Elizabeth W.; Snead III, O. C.

    2016-01-01

    New advances in structural neuroimaging have revealed the intricate and extensive connections within the brain, data which have informed a number of ambitious projects such as the mapping of the human connectome. Elucidation of the structural connections of the brain, at both the macro and micro levels, promises new perspectives on brain structure and function that could translate into improved outcomes in functional neurosurgery. The understanding of neuronal structural connectivity afforded by these data now offers a vista on the brain, in both healthy and diseased states, that could not be seen with traditional neuroimaging. Concurrent with these developments in structural imaging, a complementary modality called magnetoencephalography (MEG) has been garnering great attention because it too holds promise for being able to shed light on the intricacies of functional brain connectivity. MEG is based upon the elemental principle of physics that an electrical current generates a magnetic field. Hence, MEG uses highly sensitive biomagnetometers to measure extracranial magnetic fields produced by intracellular neuronal currents. Put simply then, MEG is a measure of neurophysiological activity, which captures the magnetic fields generated by synchronized intraneuronal electrical activity. As such, MEG recordings offer exquisite resolution in the time and oscillatory domain and, as well, when co-registered with magnetic resonance imaging (MRI), offer excellent resolution in the spatial domain. Recent advances in MEG computational and graph theoretical methods have led to studies of connectivity in the time-frequency domain. As such, MEG can elucidate a neurophysiological-based functional circuitry that may enhance what is seen with MRI connectivity studies. In particular, MEG may offer additional insight not possible by MRI when used to study complex eloquent function, where the precise timing and coordination of brain areas is critical. This article will review the

  9. Actualities and Perspectives in Neurosurgery

    PubMed Central

    Iencean, SM; Brehar, FM

    2008-01-01

    In the field of neurosurgery, like in other surgical specialties, the last decades have brought major achievements. The series of revolutionary discoveries has started during the last century in the fifties, with stereotactic radiosurgery, then continued with the implementation of operative microscope (during the seventies), the endovascular embolisation in the nineties and finally with the major improvement in robotic neurosurgery and molecular neurosurgery at the beginning of this century. The major innovation has been brought not only in the field of therapeutical measures but also in the field of neuro– imaging. Thus, the modern MRI with more than 3 Tesla, can reveal to the neurosurgeon the most intimate structures of the nervous system. Several important areas in neurosurgery like: vascular neurosurgery, functional neurosurgery and brain tumors pathology, benefit from the modern technology and from the latest discoveries from genetic and molecular biology. In conclusion, summarizing the discoveries of the last decade, we emphasize that the related areas like genetics, molecular biology, computer technology become more and more important in the future progress of the neurosurgery. PMID:20108475

  10. A fantastic voyage: a personal perspective on involvement in the development of modern stereotactic and functional neurosurgery (1974-2004).

    PubMed

    Apuzzo, Michael L J

    2005-05-01

    Stressing environments, individuals, ideas, and global events, this historical stereotactic and functional neurosurgical vignette initially presents a review of factors in the genesis of personal interest and the foundations of involvement in the discipline of neurological surgery. The vignette then traces the development of concepts and instrumentation and their ultimate practical utilization in patient care on the neurosurgical services at the Keck School of Medicine at the University of Southern California over the course of a 3-decade period (1974-2004). The article summarizes and elaborates details of contributions to the literature and complex involvement on the national and international levels as the refinements and capabilities of stereotactic and functional neurosurgery have been reinvented over a generation through the emergence of new technology, ideas, individual ingenuity, and active collegial exchange.

  11. Photolasertherapy for the treatment of infections in neurosurgery: experimental and clinical study

    NASA Astrophysics Data System (ADS)

    Lombard, Gian F.

    1996-12-01

    At the first time, the CO2 laser was utilised in infective neurosurgical pathology as a surgical cutting instrument to remove inflammatory pseudomembranes in chronic osteomyelitis, and as a vaporising instmment on the dura mater surface. Successively, the instrument, defocused and at a low power, was used for prolonged and diffuse photo coagulation ofthe surgical cavity, particularly, ofthe dural surface and ofthe osteomyelitic bone edges, with the aim to sterilise tissues. So, we saw a shortening of the average time of wound healing and a lack of recurrence of the septic pathology. Then, we have treated, with CO2 laser, intracranial infective pathology: i.e. primary abscesses, capsulated or not, circumscribed purulent encephalitis, secondary abscesses in surgical cavities (patients operated for intracranial hematomas and tumors). In these cases we have obtained a lack of septic recurrences and an improvement ofneurological post-operative course. Thank to these results, we have continued to use laser in infective pathology; for giving an experimental support to these results we have carried on researches in vivo (on the experimental animal) to see the interaction between the laser and inflammatory tissue, and in vitro (on bacterial culture: in solid and liquid media) to see the laser effect on the bacterial cell. The bacterial cell has been also sensibiized to the photo dynamic effect of the laser (Argon, He-Ne), with hematoporphyrin. The goal of these experiments is to understand the role of thermal, photochemical, and mechanic resonance laser effects in the interaction between laser radiation and bacterial cell.

  12. Discovering neurosurgery: new frontiers.

    PubMed

    Rutka, James T

    2011-12-01

    Over the centuries, discoveries of lands unknown, treasures lost and buried, and formulas to delineate physicochemical processes have led to advancements in our understanding of how the world is structured and governed. In science and medicine, discoveries are frequently made following deliberate periods of observation and experimentation to test hypotheses. However, in some instances, discoveries may arise either following a "eureka moment" that transcends rigorous scientific experimentation or following a serendipitous observation. In many instances, scientific discoveries will lead to new inventions that are aimed at improving the manner in which tasks or operations are performed. In this address, some of the key discoveries in science and medicine that have impacted significantly on the field of neurosurgery are described. Some of these include discoveries in neuroanatomy, anesthesiology, infectious diseases, antisepsis, and radiology. Discoveries in the field of molecular science, from the discovery of DNA to next-generation DNA sequencing, which have helped improve the diagnosis and prognosis of neurosurgical patients with conditions such as brain tumors, are also described. In the end, these discoveries have led us to new frontiers in the subspecialty practice of neurosurgery. Navigating our way through these new frontiers will undoubtedly lead to additional discoveries that are unimaginable at present but bound to improve the future care of neurosurgical patients.

  13. Functional Neurosurgery in the Human Thalamus by Transcranial Magnetic Resonance Guided Focused Ultrasound

    NASA Astrophysics Data System (ADS)

    Werner, Beat; Morel, Anne; Jeanmonod, Daniel; Martin, Ernst

    2009-04-01

    Potential applications of Transcranial Magnetic Resonance guided Focused Ultrasound (TcMRgFUS) include treatment of functional brain disorders, such as Parkinson's disease, dystonia and tremor, neurogenic pain and tinnitus, neuropsychiatric disorders and epilepsy. In this study we demonstrate the feasibility of non-invasive TcMRgFUS ablation of clinically well established targets in the human thalamus that are currently accessed stereotactically by interventional strategies based on the concept of the thalamocortical dysrhythmia (TCD). Thermal hotspots suitable for clinical intervention were created successfully in anatomical preparations of human ex-vivo heads under pseudo clinical conditions. The hotspots could be positioned at the target locations as needed and local energy deposition was sufficient to create tissue ablation. Numerical simulations based on these experimental data predict that the acoustic energy needed to create ablative lesions in-vivo will be within limits that can safely applied.

  14. Laser applications in neurosurgery

    NASA Astrophysics Data System (ADS)

    Cerullo, Leonard J.

    1985-09-01

    The "false start" of the laser in neurosurgery should not be misconstrued as a denial of the inherent advantages of precision and gentleness in dealing with neural tissue. Rather, early investigators were frustrated by unrealistic expectations, cumbersome equipment, and a general ignorance of microtechnique. By the early 70s, microneurosurgery was well established, surgical laser equipment for free hand and microlinked application had been developed, and a more realistic view of the limitations of the laser had been established. Consequently, the late 70s really heralded the renaissance of the laser in neurosurgery. Since then, there has been an overwhelming acceptance of the tool in a variety of clinical situations, broadly categorized in five groups. 1)|Perhaps the most generally accepted area is in the removal of extra-axial tumors of the brain and spinal cord. These tumors, benign by histology but treacherous by location, do not present until a significant amount of neurological compensation has already occurred. The application of additional trauma to the neural tissue, whether by further tumor growth or surgical manipulation, frequently results in irreversible damage. Here, the ability of the laser to vaporize tissue, in a fairly hemostatic fashion, without mechanical or thermal damage to sensitive surrounding tissues, is essential. 2)|The ability to incise delicate neural tissue with minimal spread of thermal destruction to adjacent functioning tissue makes the laser the ideal instrument when tumors deep under the surface are encountered in the brain or spinal cord. Thus, the second group of applications is in the transgression of normal neural structures to arrive at deeper pathological tissue. 3)|The third area of benefit for the laser in neurosurgery has been in the performance of neuroablative procedures, calling for deliberate destruction of functioning neural tissue in a controlled fashion. Again, the precision and shape confinement of the destructive

  15. Computers and neurosurgery.

    PubMed

    Shaikhouni, Ammar; Elder, J Bradley

    2012-11-01

    At the turn of the twentieth century, the only computational device used in neurosurgical procedures was the brain of the surgeon. Today, most neurosurgical procedures rely at least in part on the use of a computer to help perform surgeries accurately and safely. The techniques that revolutionized neurosurgery were mostly developed after the 1950s. Just before that era, the transistor was invented in the late 1940s, and the integrated circuit was invented in the late 1950s. During this time, the first automated, programmable computational machines were introduced. The rapid progress in the field of neurosurgery not only occurred hand in hand with the development of modern computers, but one also can state that modern neurosurgery would not exist without computers. The focus of this article is the impact modern computers have had on the practice of neurosurgery. Neuroimaging, neuronavigation, and neuromodulation are examples of tools in the armamentarium of the modern neurosurgeon that owe each step in their evolution to progress made in computer technology. Advances in computer technology central to innovations in these fields are highlighted, with particular attention to neuroimaging. Developments over the last 10 years in areas of sensors and robotics that promise to transform the practice of neurosurgery further are discussed. Potential impacts of advances in computers related to neurosurgery in developing countries and underserved regions are also discussed. As this article illustrates, the computer, with its underlying and related technologies, is central to advances in neurosurgery over the last half century.

  16. Feasibility of Diffusion Tractography for the Reconstruction of Intra-Thalamic and Cerebello-Thalamic Targets for Functional Neurosurgery: A Multi-Vendor Pilot Study in Four Subjects

    PubMed Central

    Jakab, András; Werner, Beat; Piccirelli, Marco; Kovács, Kázmér; Martin, Ernst; Thornton, John S.; Yousry, Tarek; Szekely, Gabor; O‘Gorman Tuura, Ruth

    2016-01-01

    Functional stereotactic neurosurgery by means of deep brain stimulation or ablation provides an effective treatment for movement disorders, but the outcome of surgical interventions depends on the accuracy by which the target structures are reached. The purpose of this pilot study was to evaluate the feasibility of diffusion tensor imaging (DTI) based probabilistic tractography of deep brain structures that are commonly used for pre- and perioperative targeting for functional neurosurgery. Three targets were reconstructed based on their significance as intervention sites or as a no-go area to avoid adverse side effects: the connections propagating from the thalamus to (1) primary and supplementary motor areas, (2) to somatosensory areas and the cerebello-thalamic tract (CTT). We evaluated the overlap of the reconstructed connectivity based targets with corresponding atlas based data, and tested the inter-subject and inter-scanner variability by acquiring repeated DTI from four volunteers, and on three MRI scanners with similar sequence parameters. Compared to a 3D histological atlas of the human thalamus, moderate overlaps of 35-50% were measured between connectivity- and atlas based volumes, while the minimal distance between the centerpoints of atlas and connectivity targets was 2.5 mm. The variability caused by the MRI scanner was similar to the inter-subject variability, except for connections with the postcentral gyrus where it was higher. While CTT resolved the anatomically correct trajectory of the tract individually, high volumetric variability was found across subjects and between scanners. DTI can be applied in the clinical, preoperative setting to reconstruct the CTT and to localize subdivisions within the lateral thalamus. In our pilot study, such subdivisions moderately matched the borders of the ventrolateral-posteroventral (VLpv) nucleus and the ventral-posterolateral (VPL) nucleus. Limitations of the currently used standard DTI protocols were

  17. Pediatric neurosurgery: pride and prejudice.

    PubMed

    Winston, K R

    2000-02-01

    Pediatric neurosurgery now exists as a member of the family of neurosurgery with its own training programs, process of accreditation, national and international conferences and scientific journals. The relentless expansion of science relevant to the practice of neurosurgery and the changing patterns of neurosurgical practice have driven and continue to drive the juggernaut of evolutionary process which sometimes necessitates the birth of new specialties of practice. The history and the development of neurosurgery as they relate to children are presented. There is no more reason to think that the established specialty of pediatric neurosurgery or the patients under the care of pediatric neurosurgeons would benefit from the collapsing of pediatric neurosurgery back into the general neurosurgical fold than to think that all of neurosurgery, and hence all patients cared for by neurosurgeons, would benefit from the return of organized neurosurgery to its general surgical parent. Just as mankind benefits from the steady advancement of all aspects of neurosurgery, children benefit from the existence and steady advancement of pediatric neurosurgery.

  18. Nanotechnology and vascular neurosurgery: an in vivo experimental study on microvessels repair using laser photoactivation of a nanostructured hyaluronan solder.

    PubMed

    Esposito, G; Rossi, F; Matteini, P; Ratto, F; Sabatino, G; Puca, A; Albanese, A; Rossi, G; Marchese, E; Maira, G; Pini, R

    2012-01-01

    Sealing tissues by laser in neurosurgical procedures may overcome problems related to the use of conventional suturing methods which can be associated with various degrees of vascular wall damage. Despite the significant experimental and clinical achievements of the past, a standardized clinical application of laser-welding technology has not yet been implemented. The main problem is related to the use of common organic chromophores. A substantial breakthrough in the laser welding of biological tissues may come from the advent of nanotechnologies. In this paper we describe an experimental study, to confirm the feasibility of an innovative laser-assisted vascular repair (LAVR) technique based on diode laser irradiation and subsequent photoactivation of a hyaluronan solder embedded with near infrared (NIR) absorbing gold nanorods (GNRs), and to analyze the induced closuring effect in a follow-up study performed in animal model. Twenty New Zealand rabbits underwent closure of a 3-mm longitudinal incision performed on the common carotid artery (CCA) by means of 810 nm diode laser irradiation, in conjunction with the topical application of an optimized GNR composite. Effective closure of the arterial wound was accomplished by using very low laser intensity (30 W/cm2). The average CCA occlusion time was as low as 50 sec. Animals underwent different follow-up periods (2, 8, 30 days). After follow-up, they were re-anesthetized, the patency of the treated vessels was tested (Doppler analysis) and then the irradiated vessels were excised and subjected to histological evaluations. Morphological examinations of the samples documented the integrity of the vascular wall. No host reaction to nanoparticles occurred. Collagen and elastic fibers returned to their normal architecture 30 days after treatment. A Scanning Electron Microscopy (SEM) examination and immuno-histochemical analysis demonstrated a full re-endothelization of the vessel walls. We thus confirmed that a laser

  19. Evidence-based neurosurgery

    PubMed Central

    Esene, Ignatius N.; Baeesa, Saleh S.; Ammar, Ahmed

    2016-01-01

    Medical evidence is obtainable from approaches, which might be descriptive, analytic and integrative and ranked into levels of evidence, graded according to quality and summarized into strengths of recommendation. Sources of evidence range from expert opinions through well-randomized control trials to meta-analyses. The conscientious, explicit, and judicious use of current best evidence in making decisions related to the care of individual patients defines the concept of evidence-based neurosurgery (EBN). We reviewed reference books of clinical epidemiology, evidence-based practice and other previously related articles addressing principles of evidence-based practice in neurosurgery. Based on existing theories and models and our cumulative years of experience and expertise conducting research and promoting EBN, we have synthesized and presented a holistic overview of the concept of EBN. We have also underscored the importance of clinical research and its relationship to EBN. Useful electronic resources are provided. The concept of critical appraisal is introduced. PMID:27356649

  20. NASA Robotic Neurosurgery Testbed

    NASA Technical Reports Server (NTRS)

    Mah, Robert

    1997-01-01

    The detection of tissue interface (e.g., normal tissue, cancer, tumor) has been limited clinically to tactile feedback, temperature monitoring, and the use of a miniature ultrasound probe for tissue differentiation during surgical operations, In neurosurgery, the needle used in the standard stereotactic CT or MRI guided brain biopsy provides no information about the tissue being sampled. The tissue sampled depends entirely upon the accuracy with which the localization provided by the preoperative CT or MRI scan is translated to the intracranial biopsy site. In addition, no information about the tissue being traversed by the needle (e.g., a blood vessel) is provided. Hemorrhage due to the biopsy needle tearing a blood vessel within the brain is the most devastating complication of stereotactic CT/MRI guided brain biopsy. A robotic neurosurgery testbed has been developed at NASA Ames Research Center as a spin-off of technologies from space, aeronautics and medical programs. The invention entitled "Robotic Neurosurgery Leading to Multimodality Devices for Tissue Identification" is nearing a state ready for commercialization. The devices will: 1) improve diagnostic accuracy and precision of general surgery, with near term emphasis on stereotactic brain biopsy, 2) automate tissue identification, with near term emphasis on stereotactic brain biopsy, to permit remote control of the procedure, and 3) reduce morbidity for stereotactic brain biopsy. The commercial impact from this work is the potential development of a whole new generation of smart surgical tools to increase the safety, accuracy and efficiency of surgical procedures. Other potential markets include smart surgical tools for tumor ablation in neurosurgery, general exploratory surgery, prostate cancer surgery, and breast cancer surgery.

  1. NASA Robotic Neurosurgery Testbed

    NASA Technical Reports Server (NTRS)

    Mah, Robert

    1997-01-01

    The detection of tissue interface (e.g., normal tissue, cancer, tumor) has been limited clinically to tactile feedback, temperature monitoring, and the use of a miniature ultrasound probe for tissue differentiation during surgical operations. In neurosurgery, the needle used in the standard stereotactic CT (Computational Tomography) or MRI (Magnetic Resonance Imaging) guided brain biopsy provides no information about the tissue being sampled. The tissue sampled depends entirely upon the accuracy with which the localization provided by the preoperative CT or MRI scan is translated to the intracranial biopsy site. In addition, no information about the tissue being traversed by the needle (e.g., a blood vessel) is provided. Hemorrhage due to the biopsy needle tearing a blood vessel within the brain is the most devastating complication of stereotactic CT/MRI guided brain biopsy. A robotic neurosurgery testbed has been developed at NASA Ames Research Center as a spin-off of technologies from space, aeronautics and medical programs. The invention entitled 'Robotic Neurosurgery Leading to Multimodality Devices for Tissue Identification' is nearing a state ready for commercialization. The devices will: 1) improve diagnostic accuracy and precision of general surgery, with near term emphasis on stereotactic brain biopsy, 2) automate tissue identification, with near term emphasis on stereotactic brain biopsy, to permit remote control of the procedure, and 3) reduce morbidity for stereotactic brain biopsy. The commercial impact from this work is the potential development of a whole new generation of smart surgical tools to increase the safety, accuracy and efficiency of surgical procedures. Other potential markets include smart surgical tools for tumor ablation in neurosurgery, general exploratory surgery, prostate cancer surgery, and breast cancer surgery.

  2. Mythology and Neurosurgery.

    PubMed

    Ökten, Ali İhsan

    2016-06-01

    Myths are the keystone of mythology. They are interpretations of events that have been told as stories and legends for thousands of years, inherited from generation to generation, and have reached the present day. Although most myths are considered figments of the imagination or fictitious legends, all of them contain references to facts from the time they occurred. Mythology, which is a collection of figments of imagination concerning nature and human beings, is a product of human effort to perceive, explain, and interpret the universe and the world, much like science. The interaction between mythology and science dates back to the early days of civilization. Mythology, a reflection of human creativity, is extensively used in modern science, particularly in a terminological context. This article aims to reveal the texture of mythology in neurosurgery, by analyzing the birth of medicine in mythology; heroes such as Apollo and Asklepios, the gods of healing and medicine, as well as Hygieia, the goddess of health and hygiene; and mythological terms and phrases such as Achilles tendon, atlas vertebra, gigantism, priapism syndrome, hippocampus, lethargy, syrinx, and arachnoid. Through the use of symbols, mythology has attempted to explain several subjects, such as human nature, disease, birth, and death. In this respect, mythology and medicine dance arm in arm, and this dance has been going on for centuries. As a result, mythology has manifested itself in many fields within medicine, either anatomically or by giving names to various diseases.

  3. Neurosurgery and clinical engineering.

    PubMed

    Salcman, M; Samaras, G M

    1978-01-01

    Modern technology has profoundly altered the clinical practice of neurosurgery. For a wide variety of conditions, patients are being implanted with active and passive devices or treated with advanced microsurgical instrumentation. After surgery, such patients are sent to modern intensive-care units employing the latest advances in patient monitoring and computer technology. We contend that the responsibilities of the Clinical Engineer extend beyond simple installation and maintenance of equipment and systems. It is essential that he take part in the continuing education of non-technical personnel who must make use of the equipment in ways that are meaningful in the care of the patient and to the progress of clinical science. This point is illustrated by our experience with a neurosurgical intensive-care unit. It is also the thesis of this paper that the design and maintenance of increasingly sophisticated biomedical systems will benefit from the use of an interdisciplinary approach at the very inception of a project. This approach is illustrated by our current development of a multibeam microwave hyperthermia system for possible use in the treatment of brain tumors.

  4. [New simulation technologies in neurosurgery].

    PubMed

    Byvaltsev, V A; Belykh, E G; Konovalov, N A

    2016-01-01

    The article presents a literature review on the current state of simulation technologies in neurosurgery, a brief description of the basic technology and the classification of simulation models, and examples of simulation models and skills simulators used in neurosurgery. Basic models for the development of physical skills, the spectrum of available computer virtual simulators, and their main characteristics are described. It would be instructive to include microneurosurgical training and a cadaver course of neurosurgical approaches in neurosurgery training programs and to extend the use of three-dimensional imaging. Technologies for producing three-dimensional anatomical models and patient-specific computer simulators as well as improvement of tactile feedback systems and display quality of virtual models are promising areas. Continued professional education necessitates further research for assessing the validity and practical use of simulators and physical models.

  5. Progress of women in neurosurgery.

    PubMed

    Spetzler, Robert F

    2011-01-01

    Despite advances in issues related to gender equity, barriers to recruiting and retaining women in neurosurgery continue to exist. At the same time, the overall projected shortage of neurosurgeons suggests that women will be vital to the long-term success of the field. Attracting women to neurosurgery can capitalize on strategies, such as mentoring, teaching leadership and negotiating skills, and job sharing or dual training tracks to name a few, that would benefit both men and women passionate about pursuing neurosurgery. Ultimately, personal and institutional accountability must be evaluated to ensure that the best and brightest candidates, regardless of gender, are recruited to neurosurgical programs to promote the health of our challenging but most satisfying profession.

  6. Progress of women in neurosurgery

    PubMed Central

    Spetzler, Robert F.

    2011-01-01

    Despite advances in issues related to gender equity, barriers to recruiting and retaining women in neurosurgery continue to exist. At the same time, the overall projected shortage of neurosurgeons suggests that women will be vital to the long-term success of the field. Attracting women to neurosurgery can capitalize on strategies, such as mentoring, teaching leadership and negotiating skills, and job sharing or dual training tracks to name a few, that would benefit both men and women passionate about pursuing neurosurgery. Ultimately, personal and institutional accountability must be evaluated to ensure that the best and brightest candidates, regardless of gender, are recruited to neurosurgical programs to promote the health of our challenging but most satisfying profession. PMID:22059098

  7. History of Neurosurgery in Malaysia

    PubMed Central

    RAFFIQ, Azman; ABDULLAH, Jafri Malin; HASPANI, Saffari; ADNAN, Johari Siregar

    2015-01-01

    The development of neurosurgical services and training in Malaysia began in 1963, with the first centre established in its capital city at Hospital Kuala Lumpur, aimed to provide much needed neurosurgical services and training in the field of neurology and neurosurgery. This center subsequently expanded in 1975 with the establishment of the Tunku Abdul Rahman Neuroscience Institute (IKTAR); which integrated the three allied interdependent disciplines of neurosurgery, neurology and psychiatry. The establishment of this institute catalysed the rapid expansion of neurosurgical services in Malaysia and paved the way for development of comprehensive training for doctors, nurses, and paramedics. This culminated in the establishments of a local comprehensive neurosurgery training program for doctors in 2001; followed by a training program for nurses and paramedics in 2006. To date, there are more than 60 neurosurgeons providing expert care in 11 centers across Malaysia, along with trained personnel in the field of neurosciences. PMID:27006632

  8. Development of a new microsurgical robot for stereotactic neurosurgery.

    PubMed

    Koyama, H; Uchida, T; Funakubo, H; Takakura, K; Fankhauser, H

    1990-01-01

    The robot technology was introduced into a new stereotactic neurosurgery system for applications to biopsy, blind surgery, and functional neurosurgery. The authors have developed a newly designed prototype microsurgical robot, designed to allow a biopsy needle to reach the target such as a cerebral tumor within a brain automatically on the basis of the X, Y, and Z coordinates obtained by CT scanner. This robot is so small that it can be driven in a CT scanner gantry. It consists mainly of the link mechanism and the insertion mechanism. We constructed the link mechanism and investigated its working space.

  9. The Co-evolution of Neuroimaging and Psychiatric Neurosurgery

    PubMed Central

    Dyster, Timothy G.; Mikell, Charles B.; Sheth, Sameer A.

    2016-01-01

    The role of neuroimaging in psychiatric neurosurgery has evolved significantly throughout the field’s history. Psychiatric neurosurgery initially developed without the benefit of information provided by modern imaging modalities, and thus lesion targets were selected based on contemporary theories of frontal lobe dysfunction in psychiatric disease. However, by the end of the 20th century, the availability of structural and functional magnetic resonance imaging (fMRI) allowed for the development of mechanistic theories attempting to explain the anatamofunctional basis of these disorders, as well as the efficacy of stereotactic neuromodulatory treatments. Neuroimaging now plays a central and ever-expanding role in the neurosurgical management of psychiatric disorders, by influencing the determination of surgical candidates, allowing individualized surgical targeting and planning, and identifying network-level changes in the brain following surgery. In this review, we aim to describe the coevolution of psychiatric neurosurgery and neuroimaging, including ways in which neuroimaging has proved useful in elucidating the therapeutic mechanisms of neuromodulatory procedures. We focus on ablative over stimulation-based procedures given their historical precedence and the greater opportunity they afford for post-operative re-imaging, but also discuss important contributions from the deep brain stimulation (DBS) literature. We conclude with a discussion of how neuroimaging will transition the field of psychiatric neurosurgery into the era of precision medicine. PMID:27445706

  10. 3D printing in neurosurgery: A systematic review

    PubMed Central

    Randazzo, Michael; Pisapia, Jared M.; Singh, Nickpreet; Thawani, Jayesh P.

    2016-01-01

    Background: The recent expansion of three-dimensional (3D) printing technology into the field of neurosurgery has prompted a widespread investigation of its utility. In this article, we review the current body of literature describing rapid prototyping techniques with applications to the practice of neurosurgery. Methods: An extensive and systematic search of the Compendex, Scopus, and PubMed medical databases was conducted using keywords relating to 3D printing and neurosurgery. Results were manually screened for relevance to applications within the field. Results: Of the search results, 36 articles were identified and included in this review. The articles spanned the various subspecialties of the field including cerebrovascular, neuro-oncologic, spinal, functional, and endoscopic neurosurgery. Conclusions: We conclude that 3D printing techniques are practical and anatomically accurate methods of producing patient-specific models for surgical planning, simulation and training, tissue-engineered implants, and secondary devices. Expansion of this technology may, therefore, contribute to advancing the neurosurgical field from several standpoints. PMID:27920940

  11. Anaesthesia for elective neurosurgery.

    PubMed

    Dinsmore, J

    2007-07-01

    Neuroanaesthesia continues to develop and expand. It is a speciality where the knowledge and expertise of the anaesthetist can directly influence patient outcome. Evolution of neurosurgical practice is accompanied by new challenges for the anaesthetist. Increasingly, we must think not only as an anaesthetist but also as a neurosurgeon and neurologist. With the focus on functional and minimally invasive procedures, there is an increased emphasis on the provision of optimal operative conditions, preservation of neurocognitive function, minimizing interference with electrophysiological monitoring, and a rapid, high-quality recovery. Small craniotomies, intraoperative imaging, stereotactic interventions, and endoscopic procedures increase surgical precision and minimize trauma to normal tissues. The result should be quicker recovery, minimal perioperative morbidity, and reduced hospital stay. One of the peculiarities of neuroanaesthesia has always been that as much importance is attached to wakening the patient as sending them to sleep. With the increasing popularity of awake craniotomies, there is even more emphasis on this skill. However, despite high-quality anaesthetic research and advances in drugs and monitoring modalities, many controversies remain regarding best clinical practice. This review will discuss some of the current controversies in elective neurosurgical practice, future perspectives, and the place of awake craniotomies in the armamentarium of the neuroanaesthetist.

  12. Virtual neurosurgery, training for the future.

    PubMed

    Vloeberghs, M; Glover, A; Benford, S; Jones, A; Wang, P; Becker, Adib

    2007-06-01

    Virtual reality (VR) simulators have been created for various surgical specialties. The common theme is extensive use of graphics, confined spaces, limited functionality and limited tactile feedback. A development team at the University of Nottingham, UK, consisting of computer scientists, mechanical engineers, graphic designers and a neurosurgeon, set out to develop a haptic, e.g. tactile simulator for neurosurgery making use of boundary elements (BE). The relative homogeneity of the brain, allows boundary elements, e.g. 'surface only' rendering, to simulate the brain structure. A boundary element simplifies the computing equations saves computing time, by assuming the properties of the surface equal the properties of the body. A limited audit was done by neurosurgical users confirming the potential of the simulator as a training tool. This paper focuses on the application of the computational method and refers to the underlying mathematical structure. Full references are included regarding the mathematical methodology.

  13. Challenges in contemporary academic neurosurgery.

    PubMed

    Black, Peter M

    2006-03-01

    Traditionally, the ideal academic neurosurgeon has been a "quadruple threat," with excellence in clinical work, teaching, research, and administration. This tradition was best exemplified in Harvey Cushing, who developed the field of neurosurgery 90 years ago. This paradigm will probably have to change as academic neurosurgeons face major challenges. In patient care, these include increasing regulatory control, increasing malpractice costs, consolidation of expensive care in academic centers, and decreasing reimbursement; in resident teaching, work hour limitations and a changing resident culture; in research, the increasing dominance of basic scientists in governmental funding decisions and decreased involvement of neurosurgeons in scientific review committees; and in administration, problems of relationships in the workplace, patient safety, and employment compliance in an increasingly bureaucratic system. To meet these challenges, the new academic neurosurgeon will probably not be a quadruple threat personally but will be part of a quadruple threat in a department and institution. Neurosurgeons in such a setting will have to work with hospital, medical school, and national and international groups to address malpractice, reimbursement, subspecialization, and training problems; find supplemental sources of income through grants, development funds, and hospital support; lead in the development of multidisciplinary centers for neuroscience, brain tumor, spine, and other initiatives; and focus on training leaders for hospital, regional, and national groups to reconfigure neurosurgery. Collaboration, flexibility, and leadership will be characteristic of the academic neurosurgeon in this new era.

  14. Dynamic hub load predicts cognitive decline after resective neurosurgery

    PubMed Central

    Carbo, Ellen W. S.; Hillebrand, Arjan; van Dellen, Edwin; Tewarie, Prejaas; de Witt Hamer, Philip C.; Baayen, Johannes C.; Klein, Martin; Geurts, Jeroen J. G.; Reijneveld, Jaap C.; Stam, Cornelis J.; Douw, Linda

    2017-01-01

    Resective neurosurgery carries the risk of postoperative cognitive deterioration. The concept of ‘hub (over)load’, caused by (over)use of the most important brain regions, has been theoretically postulated in relation to symptomatology and neurological disease course, but lacks experimental confirmation. We investigated functional hub load and postsurgical cognitive deterioration in patients undergoing lesion resection. Patients (n = 28) underwent resting-state magnetoencephalography and neuropsychological assessments preoperatively and 1-year after lesion resection. We calculated stationary hub load score (SHub) indicating to what extent brain regions linked different subsystems; high SHub indicates larger processing pressure on hub regions. Dynamic hub load score (DHub) assessed its variability over time; low values, particularly in combination with high SHub values, indicate increased load, because of consistently high usage of hub regions. Hypothetically, increased SHub and decreased DHub relate to hub overload and thus poorer/deteriorating cognition. Between time points, deteriorating verbal memory performance correlated with decreasing upper alpha DHub. Moreover, preoperatively low DHub values accurately predicted declining verbal memory performance. In summary, dynamic hub load relates to cognitive functioning in patients undergoing lesion resection: postoperative cognitive decline can be tracked and even predicted using dynamic hub load, suggesting it may be used as a prognostic marker for tailored treatment planning. PMID:28169349

  15. Dynamic hub load predicts cognitive decline after resective neurosurgery.

    PubMed

    Carbo, Ellen W S; Hillebrand, Arjan; van Dellen, Edwin; Tewarie, Prejaas; de Witt Hamer, Philip C; Baayen, Johannes C; Klein, Martin; Geurts, Jeroen J G; Reijneveld, Jaap C; Stam, Cornelis J; Douw, Linda

    2017-02-07

    Resective neurosurgery carries the risk of postoperative cognitive deterioration. The concept of 'hub (over)load', caused by (over)use of the most important brain regions, has been theoretically postulated in relation to symptomatology and neurological disease course, but lacks experimental confirmation. We investigated functional hub load and postsurgical cognitive deterioration in patients undergoing lesion resection. Patients (n = 28) underwent resting-state magnetoencephalography and neuropsychological assessments preoperatively and 1-year after lesion resection. We calculated stationary hub load score (SHub) indicating to what extent brain regions linked different subsystems; high SHub indicates larger processing pressure on hub regions. Dynamic hub load score (DHub) assessed its variability over time; low values, particularly in combination with high SHub values, indicate increased load, because of consistently high usage of hub regions. Hypothetically, increased SHub and decreased DHub relate to hub overload and thus poorer/deteriorating cognition. Between time points, deteriorating verbal memory performance correlated with decreasing upper alpha DHub. Moreover, preoperatively low DHub values accurately predicted declining verbal memory performance. In summary, dynamic hub load relates to cognitive functioning in patients undergoing lesion resection: postoperative cognitive decline can be tracked and even predicted using dynamic hub load, suggesting it may be used as a prognostic marker for tailored treatment planning.

  16. Renaissance Neurosurgery: Italy's Iconic Contributions.

    PubMed

    Nanda, Anil; Khan, Imad Saeed; Apuzzo, Michael L

    2016-03-01

    Various changes in the sociopolitical milieu of Italy led to the increasing tolerance of the study of cadavers in the late Middle Ages. The efforts of Mondino de Liuzzi (1276-1326) and Guido da Vigevano (1280-1349) led to an explosion of cadaver-centric studies in centers such as Bologna, Florence, and Padua during the Renaissance period. Legendary scientists from this era, including Leonardo Da Vinci, Andreas Vesalius, Bartolomeo Eustachio, and Costanzo Varolio, furthered the study of neuroanatomy. The various texts produced during this period not only helped increase the understanding of neuroanatomy and neurophysiology but also led to the formalization of medical education. With increased understanding came new techniques to address various neurosurgical problems from skull fractures to severed peripheral nerves. The present study aims to review the major developments in Italy during the vibrant Renaissance period that led to major progress in the field of neurosurgery.

  17. Registration in neurosurgery and neuroradiotherapy applications.

    PubMed

    Cuchet, E; Knoplioch, J; Dormont, D; Marsault, C

    1995-01-01

    Because of the high level of accuracy needed in neurosurgery, many computer-assisted surgery (CAS) and augmented reality techniques have been developed in this field. A common issue with all of these techniques is registration between preoperative three-dimensional images (computed tomography and magnetic resonance imaging) and the patient in the operating room. We present, in the first part of this paper, a survey of the latest CAS technologies, using fully automatic registration without fiducial landmarks. All of the registration algorithms described are based on minimization of a cost function. We then describe our approach. Our cost function is simply the mean square error (MSE), minimized by the iterative closest point algorithm (ICP). Because the weak point of the ICP algorithm is the closest point computational cost, we precalculate it by a "closest point map," inspired from classical distance map. We finally perturb the found solution to eliminate local minima close to the global minimum. This paper summarizes the various methods presented. We study the shape of the different cost functions and show that there is no need for a complex cost function. MSE has sufficiently good convergence properties to reach a position very close to the global minimum. We also demonstrate the influence of a final perturbation of the found solution to improve registration. Finally, we test the registration on different regions of the patient's head.

  18. [Changing the teaching of neurosurgery with information technology].

    PubMed

    Moreau, Jean-Jacques; Caire, François; Kalamarides, Michel; Mireau, Etienne; Dauger, Frédéric; Coignac, Marie-Jo; Charlin, Bernard

    2009-10-01

    A digital campus is a distance learning site that uses the potential of information and communication technologies to disseminate and improve educational services. This website, with open and free access, is built from free software with Web 2.0 technology. It is hosted at the University of Limoges. It functions as a digital library, containing scanned books, slide shows, more than 200 hours of recorded courses and round tables accessible by streaming video. The site is indexed according to the users' needs, by level of knowledge, specialty, keywords, and supplementary MeSH terms. The campus is organized as the College of Neurosurgery (http://college.neurochirurgie.fr). The durability of this type of training (in existence for 9 years now) is made possible by a powerful and committed consortium: the French Society of Neurosurgery, which has created high-quality intellectual and scientific resources, the University of Limoges, the Dupuytren University Hospital Center in Limoges, the region of Limousin, and the French-language Virtual Medical University, which have provided logistic and financial support. To target appropriate levels at various users, we distinguished four groups: medical students, neurosurgery students, neurosurgeons (continuing medical education), and students in allied health fields. All areas of neurosurgery are concerned. All the courses, including tests for self-evaluation and scientific meetings (organized with information and communication technologies) are digitally recorded for the site. The principles that make it possible for a medical discipline to organize around an online project are: a pedagogical conception of projects built in the form of models reusable by other health specialties; a stronghold within professional societies of the relevant specialties able to create high-quality intellectual and scientific resources; an organization by educational levels that can be extended transversally to other health disciplines; and free

  19. Clovis Vincent (1879-1947): founder of French neurosurgery and promoter of oncologic neurosurgery.

    PubMed

    Karamanou, M; Androutsos, G; Lymperi, M; Stamboulis, E; Liappas, I; Lykouras, E

    2012-01-01

    The eminent neurologist Clovis Vincent decided to become neurosurgeon at an advanced age. His is considered the founder of French neurosurgery and the Europe's first neurosurgeon. He was mainly interested in pituitary tumors and his work on oncologic neurosurgery remains valuable.

  20. Global Neurosurgery: The Unmet Need.

    PubMed

    Park, Kee B; Johnson, Walter D; Dempsey, Robert J

    2016-04-01

    Globally, the lack of access to basic surgical care causes 3 times as much deaths as HIV/AIDS, tuberculosis, and malaria combined. The magnitude of this unmet need has been described recently, and the numbers are startling. Major shifts in global health agenda have highlighted access to essential and emergency surgery as a high priority. A broad examination of the current global neurosurgical efforts to improve access has revealed some strengths, particularly in the realm of training; however, the demand grossly outstrips the supply; most people in low-income countries do not have access to basic surgical care, either due to lack of availability or affordability. Projects that help create a robust and resilient health system within low- and middle-income countries require urgent implementation. In this context, concurrent scale-up of human resources, investments in capacity building, local data collection, and analysis for accurate assessment are essential. In addition, through process of collaboration and consensus building within the neurosurgical community, a unified voice of neurosurgery is necessary to effectively advocate for all those who need neurosurgical care wherever, whenever.

  1. Simulation and resident education in spinal neurosurgery

    PubMed Central

    Bohm, Parker E.; Arnold, Paul M.

    2015-01-01

    Background: A host of factors have contributed to the increasing use of simulation in neurosurgical resident education. Although the number of simulation-related publications has increased exponentially over the past two decades, no studies have specifically examined the role of simulation in resident education in spinal neurosurgery. Methods: We performed a structured search of several databases to identify articles detailing the use of simulation in spinal neurosurgery education in an attempt to catalogue potential applications for its use. Results: A brief history of simulation in medicine is given, followed by current trends of spinal simulation utilization in residency programs. General themes from the literature are identified that are integral for implementing simulation into neurosurgical residency curriculum. Finally, various applications are reported. Conclusion: The use of simulation in spinal neurosurgery education is not as ubiquitous in comparison to other neurosurgical subspecialties, but many promising methods of simulation are available for augmenting resident education. PMID:25745588

  2. Magnetic resonance susceptibility weighted imaging in neurosurgery: current applications and future perspectives.

    PubMed

    Di Ieva, Antonio; Lam, Timothy; Alcaide-Leon, Paula; Bharatha, Aditya; Montanera, Walter; Cusimano, Michael D

    2015-12-01

    Susceptibility weighted imaging (SWI) is a relatively new imaging technique. Its high sensitivity to hemorrhagic components and ability to depict microvasculature by means of susceptibility effects within the veins allow for the accurate detection, grading, and monitoring of brain tumors. This imaging modality can also detect changes in blood flow to monitor stroke recovery and reveal specific subtypes of vascular malformations. In addition, small punctate lesions can be demonstrated with SWI, suggesting diffuse axonal injury, and the location of these lesions can help predict neurological outcome in patients. This imaging technique is also beneficial for applications in functional neurosurgery given its ability to clearly depict and differentiate deep midbrain nuclei and close submillimeter veins, both of which are necessary for presurgical planning of deep brain stimulation. By exploiting the magnetic susceptibilities of substances within the body, such as deoxyhemoglobin, calcium, and iron, SWI can clearly visualize the vasculature and hemorrhagic components even without the use of contrast agents. The high sensitivity of SWI relative to other imaging techniques in showing tumor vasculature and microhemorrhages suggests that it is an effective imaging modality that provides additional information not shown using conventional MRI. Despite SWI's clinical advantages, its implementation in MRI protocols is still far from consistent in clinical usage. To develop a deeper appreciation for SWI, the authors here review the clinical applications in 4 major fields of neurosurgery: neurooncology, vascular neurosurgery, neurotraumatology, and functional neurosurgery. Finally, they address the limitations of and future perspectives on SWI in neurosurgery.

  3. Fetal neurosurgery: current state of the art

    PubMed Central

    Saadai, Payam; Runyon, Timothy; Farmer, Diana L

    2011-01-01

    Congenital CNS abnormalities have been targets for prenatal intervention since the founding of fetal surgery 30 years ago, but with historically variable results. Open fetal neurosurgery for myelomenigocele has demonstrated the most promising results of any CNS malformation. Improvements in the understanding of congenital diseases and in fetal surgical techniques have reopened the door to applying fetal surgery to other congenital CNS abnormalities. Advances in gene therapy, bioengineering and neonatal neuroprotection will aid in the future expansion of fetal neurosurgery to other CNS disorders. PMID:21709818

  4. [From stone trephine to robots, 5000 years of neurosurgery].

    PubMed

    Reinhardt, H F

    1990-01-16

    Only a century has elapsed since the first serious surgical interventions on the human brain were undertaken; man has however sought to understand its structure and function for several thousand years in order to reach therapeutic consequences. A few highlights of brain research and neurosurgery from the neolithic to current times are described along with the prevailing views and technologies. Parallels are drawn with examples from clock making. An outlook to computer aided surgery (CAS) combining modern imaging techniques with data processing and technical operative innovation is given.

  5. Modernity and the emerging futurism in neurosurgery.

    PubMed

    Apuzzo, M L

    2000-03-01

    This article discusses the emergence of neurosurgery in its 'modern' form during the second half of the 20th century and presents the apertures to the 21st century that are apparent in establishing an evolving futurism in the field. Factors of primary positive impetus and challenges are discussed.

  6. Use of ADCON in neurosurgery: preclinical review.

    PubMed

    Lo, H; Frederickson, R C

    1999-01-01

    ADCON-L and ADCON-T/N are two bioabsorbable adhesion barrier gels designed to inhibit post-operative fibrosis around the dura and nerve structure. Two ADCON products were evaluated in animal models emulating their use in neurosurgery. In all studies ADCON-L and ADCON-T/N were safe and effective barriers to post-operative peridural and perineural fibrosis.

  7. Neurosurgery: A profession or a technical trade?

    PubMed Central

    Watts, Clark

    2014-01-01

    The American Association of Neurological Surgeons (AANS), 11 years ago converted its Internal Revenue Code (IRC) tax status from a 501 (c) (3) to a 501 (c) (6) entity. By doing so, the professional medical association, now a trade association, was able to more aggressively lobby, support political campaigns, and pursue business opportunities for its members. In the following decade, major changes were seen in the practice of neurosurgery, especially as it relates to spine surgery. With the majority of neurosurgeons limiting themselves to a spine practice, an increased number of spinal procedures, most noted in the Medicare population, was recorded. For example, a 15-fold increase in complex spinal fusions for spinal stenosis was seen between 2002 and 2007. While the basis for this increase was not readily apparent, it was associated with a reduction in reimbursement per case of about 50%, fueling the belief that the increase in complexity of surgery permitted recovery of fees in complex cases to off-set the loss of reimbursement for simpler cases. Considering the growth of spinal surgery within neurosurgery, and decrease funding for spine surgery, in the future there may be too many surgeons chasing too few dollars. There appears to be within neurosurgery a crisis developing where future manpower projections do not realistically match future anticipated specialty funding. PMID:25558426

  8. [The origins of the French neurosurgery].

    PubMed

    Brunon, J

    2016-06-01

    Modern French neurosurgery starts at the beginning of the XXth century under the motivation of Joseph Babinski. He submitted his patients to Thierry de Martel who had learned this new specialized area of medicine with H. Cushing in the États-Unis and V. Horsey in Great Britain. His first successfully treated case of an intracranial tumor was published in 1909. But the true founding father was Clovis Vincent, initially a neurologist and collaborator of de Martel, who became the first chairman in 1933 of the neurosurgical department at the Pitié hospital of Paris and the first professor of neurosurgery in 1938. After the Second World War, many departments were created outside of Paris. Neurosurgery was definitively recognized as a specialized area in medicine in 1948. Currently, more than 400 neurosurgeons work in France. Because I had the very great privilege to be present at the birth of this society in 1970 and to still be in contact with some of the second and third generation of French neurosurgeons who led it to its high international recognition, the Chairman of the French Neurosurgical Society asked me to write this short historical vignette.

  9. Photodynamic application in neurosurgery: present and future

    NASA Astrophysics Data System (ADS)

    Kostron, Herwig

    2009-06-01

    Photodynamic techniques such as photodynamic diagnosis (PDD), fluorescence guided tumor resection (FGR) and photodynamic therapy (PDT) are currently undergoing intensive clinical investigations as adjunctive treatment for malignant brain tumours. This review provides an overview on the current clinical data and trials as well as on photosensitisers, technical developments and indications for photodynamic application in Neurosurgery. Furthermore new developments and clinical significance of FGR for neurosurgery will be discussed. Over 1000 patients were enrolled in various clinical phase I/II trials for PDT for malignant brain tumours. Despite various treatment protocols, variation of photosensitisers and light dose there is a clear trend towards prolonging median survival after one single PDT as compared to conventional therapeutic modalities. The median survival after PDT for primary glioblastoma multiforme WHO IV was 19 months and for recurrent GBM 9 months as compared to standard convential treatment which is 15 months and 3 months, respectively. FGR in combination with adjunctive radiation was significantly superior to standard surgical resection followed by radiation. The combination of FGR/PDD and intraoperative PDT increased significantly survival in recurrent glioblastoma patients. The combination of PDD/ FGR and PDT offers an exciting approach to the treatment of malignant brain tumours "to see and to treat." PDT was generally well tolerated and side effects consisted of occasionally increased intracranial pressure and prolonged skin sensitivity against direct sunlight. This review covers the current available data and draws the future potential of PDD and PDT for its application in neurosurgery.

  10. Neurosurgery: A profession or a technical trade?

    PubMed

    Watts, Clark

    2014-01-01

    The American Association of Neurological Surgeons (AANS), 11 years ago converted its Internal Revenue Code (IRC) tax status from a 501 (c) (3) to a 501 (c) (6) entity. By doing so, the professional medical association, now a trade association, was able to more aggressively lobby, support political campaigns, and pursue business opportunities for its members. In the following decade, major changes were seen in the practice of neurosurgery, especially as it relates to spine surgery. With the majority of neurosurgeons limiting themselves to a spine practice, an increased number of spinal procedures, most noted in the Medicare population, was recorded. For example, a 15-fold increase in complex spinal fusions for spinal stenosis was seen between 2002 and 2007. While the basis for this increase was not readily apparent, it was associated with a reduction in reimbursement per case of about 50%, fueling the belief that the increase in complexity of surgery permitted recovery of fees in complex cases to off-set the loss of reimbursement for simpler cases. Considering the growth of spinal surgery within neurosurgery, and decrease funding for spine surgery, in the future there may be too many surgeons chasing too few dollars. There appears to be within neurosurgery a crisis developing where future manpower projections do not realistically match future anticipated specialty funding.

  11. Molecular neurosurgery: vectors and vector delivery strategies.

    PubMed

    White, Edward

    2012-12-01

    Molecular neurosurgery involves the use of vector-mediated gene therapy and gene knockdown to manipulate in vivo gene expression for the treatment of neurological diseases. These techniques have the potential to revolutionise the practice of neurosurgery. However, significant challenges remain to be overcome before these techniques enter routine clinical practice. These challenges have been the subject of intensive research in recent years and include the development of strategies to facilitate effective vector delivery to the brain and the development of both viral and non-viral vectors that are capable of efficient cell transduction without excessive toxicity. This review provides an update on the practice of molecular neurosurgery with particular focus on the practical neurosurgical aspects of vector delivery to the brain. In addition, an introduction to the key vectors employed in clinical trials and a brief overview of previous gene therapy clinical trials is provided. Finally, key areas for future research aimed at increasing the likelihood of the successful translation of gene therapy into clinical trials are highlighted.

  12. Socioeconomic issues of United States military neurosurgery.

    PubMed

    Moquin, Ross R; Ecklund, James M

    2002-04-15

    Although the practice of neurosurgery in the United States (US) Armed Forces is in many ways similar to the civilian practice of neurosurgery, there are many differences as well. The unique challenges, duties, and opportunities US military neurosurgeons are given, both in peacetime and in times of conflict, are discussed, as are pathways for entering into service. The advantages of military service for neurosurgeons include sponsored training, decreased direct exposure to tort actions, little involvement with third-party payers, significant opportunities for travel, and military specific experiences. The most appealing aspect of military practice is serving fellow members of the US Armed Forces. Disadvantages include the extreme gap between the military and civilian pay scales, lack of support personnel, and in some areas low surgery-related case volume. The greatest concern faced by the military neurosurgical community is the failure to retain experienced neurosurgeons after their obligated service time has been completed, for which several possible solutions are described. It is hoped that future changes will make the practice of military neurosurgery attractive enough so that it will be seen as a career in itself and not an obligation to endure before starting practice in the "real world."

  13. Art, passion, and neurosurgery: the role of the Society of Neurological Surgeons in academic neurosurgery.

    PubMed

    Dempsey, Robert J

    2011-11-01

    Neurosurgery is at a crossroads in a time of economic uncertainty. It is also a time of remarkable potential for innovation resulting in dramatic improvement in the way neurosurgeons care for patients and the quality of outcomes. Analysis of this key time point of neurosurgical history is drawn from reflections for a presidential address to the Society of Neurological Surgeons. It is the author's opinion that the best of academic neurosurgery must and will accept this challenge by developing not only the research but also the creativity and art of what neurosurgeons do for maximal patient benefit in research, educational, and clinical missions.

  14. Laser Nano-Neurosurgery from Gentle Manipulation to Nano-Incision of Neuronal Cells and Scaffolds: An Advanced Neurotechnology Tool

    PubMed Central

    Soloperto, Alessandro; Palazzolo, Gemma; Tsushima, Hanako; Chieregatti, Evelina; Vassalli, Massimo; Difato, Francesco

    2016-01-01

    Current optical approaches are progressing far beyond the scope of monitoring the structure and function of living matter, and they are becoming widely recognized as extremely precise, minimally-invasive, contact-free handling tools. Laser manipulation of living tissues, single cells, or even single-molecules is becoming a well-established methodology, thus founding the onset of new experimental paradigms and research fields. Indeed, a tightly focused pulsed laser source permits complex tasks such as developing engineered bioscaffolds, applying calibrated forces, transfecting, stimulating, or even ablating single cells with subcellular precision, and operating intracellular surgical protocols at the level of single organelles. In the present review, we report the state of the art of laser manipulation in neuroscience, to inspire future applications of light-assisted tools in nano-neurosurgery. PMID:27013962

  15. Laser Nano-Neurosurgery from Gentle Manipulation to Nano-Incision of Neuronal Cells and Scaffolds: An Advanced Neurotechnology Tool.

    PubMed

    Soloperto, Alessandro; Palazzolo, Gemma; Tsushima, Hanako; Chieregatti, Evelina; Vassalli, Massimo; Difato, Francesco

    2016-01-01

    Current optical approaches are progressing far beyond the scope of monitoring the structure and function of living matter, and they are becoming widely recognized as extremely precise, minimally-invasive, contact-free handling tools. Laser manipulation of living tissues, single cells, or even single-molecules is becoming a well-established methodology, thus founding the onset of new experimental paradigms and research fields. Indeed, a tightly focused pulsed laser source permits complex tasks such as developing engineered bioscaffolds, applying calibrated forces, transfecting, stimulating, or even ablating single cells with subcellular precision, and operating intracellular surgical protocols at the level of single organelles. In the present review, we report the state of the art of laser manipulation in neuroscience, to inspire future applications of light-assisted tools in nano-neurosurgery.

  16. Smartphone use in neurosurgery? APP-solutely!

    PubMed Central

    Zaki, Michael; Drazin, Doniel

    2014-01-01

    Background: A number of smartphone medical apps have recently emerged that may be helpful for the neurosurgical patient, practitioner, and trainee. This study aims to review the current neurosurgery-focused apps available for the iPhone, iPad, and Android platforms as of December 2013. Methods: Two of the most popular smartphone app stores (Apple Store and Android Google Play Store) were surveyed for neurosurgery-focused apps in December 2013. Search results were categorized based on their description page. Data were collected on price, rating, app release date, target audience, and medical professional involvement in app design. A review of the top apps in each category was performed. Results: The search resulted in 111 unique apps, divided into these 7 categories: 16 (14%) clinical tools, 17 (15%) conference adjunct, 27 (24%) education, 18 (16%) literature, 15 (14%) marketing, 10 (9%) patient information, and 8 (7%) reference. The average cost of paid apps was $23.06 (range: $0.99-89.99). Out of the 111 apps, 71 (64%) were free, 48 (43%) had reviews, and 14 (13%) had more than 10 reviews. Seventy-three (66%) apps showed evidence of medical professional involvement. The number of apps being released every year has been increasing since 2009. Conclusions: There are a number of neurosurgery-themed apps available to all audiences. There was a lack of patient information apps for nonspinal procedures. Most apps did not have enough reviews to evaluate their quality. There was also a lack of oversight to validate the accuracy of medical information provided in these apps. PMID:25101208

  17. Application of Predictive Nursing Reduces Psychiatric Complications in ICU Patients after Neurosurgery

    PubMed Central

    LIU, Qiong; ZHU, Hui

    2016-01-01

    Background: Our aim was to investigate the effects of clinical application of perioperative predictive nursing on reducing psychiatric complications in Intensive Care Unit (ICU) patients after neurosurgery. Methods: A total of 129 patients who underwent neurosurgery and received intensive care were enrolled in our study from February 2013 to February 2014. These patients were divided into two groups: the experimental group (n=68) receiving predictive nursing before and after operation, and the control group (n=61) with general nursing. Clinical data including length of ICU stay, duration of the patients’ psychiatric symptoms, form and incidence of adverse events, and patient satisfaction ratings were recorded, and their differences between the two groups were analyzed. Results: The duration of psychiatric symptoms and the length of ICU stay for patients in the experimental group were significantly shorter than those in the control group (P<0.05). The incidence of adverse events and psychiatric symptoms, such as sensory and intuition disturbance, thought disturbance, emotional disorder, and consciousness disorder, in the experimental group was significantly lower than that in the control group (P<0.05). Patient satisfaction ratings were significantly higher in the experimental group than those in the control group (P<0.05). Conclusion: Application of predictive nursing on ICU patients who undergo neurosurgery could effectively reduce the incidence of psychiatric symptoms as well as other adverse events. Our study provided clinical evidences to encourage predictive nursing in routine settings for patients in critical conditions. PMID:27252916

  18. Experimental measurement of the Melnikov function

    NASA Astrophysics Data System (ADS)

    Meunier, Patrice; Huck, Peter; Nobili, Clément; Villermaux, Emmanuel

    2015-07-01

    We study the transport properties of a genuine two-dimensional flow with a large mean velocity perturbed periodically in time by means of an original experimental technique. The flow generated by the co-rotation of two cylinders is both stratified with a linear density gradient using salted water and viscous in order to prevent Ekman pumping and centrifugal instabilities. Thus, the mean flow contains a hyperbolic point with a homoclinic streamline, which we perturb periodically by an extra oscillation. A blob of scalar injected close to the stagnation point contracts on the stable manifold and stretches in the unstable direction. The distance between the stable and the unstable manifolds is measured as the distance between the maximum and the minimum of the dye undulating pattern and is recorded as a function of the perturbation frequency. This distance, also called the Melnikov function, presents a maximum when the residence time of a fluid particle in the mean flow is about half a perturbation period. This resonance criterion is recovered with good quantitative agreement by the theoretical prediction of the Melnikov function computed for this flow.

  19. Mythological and Prehistorical Origins of Neurosurgery.

    PubMed

    Nanda, Anil; Filis, Andreas; Kalakoti, Piyush

    2016-05-01

    Mythology has a cultural appeal, and the description of some neurosurgical procedures in the Hindu, Greek, Egyptian, and Chinese mythology has a bearing to the origins of our professions. The traces to some of our modern-day practices also can be linked back to the ancient prehistoric eras of the Siberian, Persian, and the Andean region. In this historical perspective, we briefly dwell into individual accounts through the prism of different cultures to highlight the development of neurosurgery in mythology and prehistoric era.

  20. Genealogy of training in vascular neurosurgery.

    PubMed

    Chowdhry, Shakeel A; Spetzler, Robert F

    2014-02-01

    Remarkable advances and changes in the landscape of neurovascular disease have occurred recently. Concurrently, a paradigm shift in training and resident education is underway. This crossroad of unique opportunities and pressures necessitates creative change in the training of future vascular neurosurgeons to allow incorporation of surgical advances, new technology, and supplementary treatment modalities in a setting of reduced work hours and increased public scrutiny. This article discusses the changing landscape in neurovascular disease treatment, followed by the recent changes in resident training, and concludes with our view of the future of training in vascular neurosurgery.

  1. Graph theory analysis of complex brain networks: new concepts in brain mapping applied to neurosurgery.

    PubMed

    Hart, Michael G; Ypma, Rolf J F; Romero-Garcia, Rafael; Price, Stephen J; Suckling, John

    2016-06-01

    Neuroanatomy has entered a new era, culminating in the search for the connectome, otherwise known as the brain's wiring diagram. While this approach has led to landmark discoveries in neuroscience, potential neurosurgical applications and collaborations have been lagging. In this article, the authors describe the ideas and concepts behind the connectome and its analysis with graph theory. Following this they then describe how to form a connectome using resting state functional MRI data as an example. Next they highlight selected insights into healthy brain function that have been derived from connectome analysis and illustrate how studies into normal development, cognitive function, and the effects of synthetic lesioning can be relevant to neurosurgery. Finally, they provide a précis of early applications of the connectome and related techniques to traumatic brain injury, functional neurosurgery, and neurooncology.

  2. Current Status and Future Prospect of Endovascular Neurosurgery

    PubMed Central

    Jeon, Young Il

    2008-01-01

    Recently, due to the evolution of technology, the field of neurosurgery is receiving spotlight. In particular endovascular neurosurgery has gained a great interest along with the advancement of the modern neurosurgery. The most remarkable advances were made in embolization of the cerebral aneurysms, arteriovenous malformations and intracranial stenosis during the past 10 years. These advances will further change the role of neurosurgeons in treating cerebrovascular disease. Because interventional neuroradiologists have performed most of procedures in the past, neurosurgeons have been deprived of chances to learn endovascular procedure. This article discusses the development of technological aspect of endovascular neurosurgery in chronological order. By understanding the history and current status of the endovascular surgery, the future of neurosurgery will be promising. PMID:19096608

  3. Infrared lidar overlap function: an experimental determination.

    PubMed

    Guerrero-Rascado, Juan Luis; Costa, Maria João; Bortoli, Daniele; Silva, Ana Maria; Lyamani, Hassan; Alados-Arboledas, Lucas

    2010-09-13

    The most recent works demonstrate that the lidar overlap function, which describes the overlap between the laser beam and the receiver field of view, can be determined experimentally for the 355 and 532 nm channels using Raman signals. Nevertheless, the Raman channels cannot be used to determine the lidar overlap for the infrared channel (1064 nm) because of their low intensity. In addition, many Raman lidar systems only provide inelastic signals with reasonable signal-to-noise ratio at nighttime. In view of this fact, this work presents a modification of that method, based on the comparison of attenuated backscatter profiles derived from lidar and ceilometer, to retrieve the overlap function for the lidar infrared channel. Similarly to the Raman overlap method, the approach presented here allows to derive the overlap correction without an explicit knowledge of all system parameters. The application of the proposed methodology will improve the potential of Raman lidars to investigate the aerosol microphysical properties in the planetary boundary layer, extending the information of 1064 nm backscatter profiles to the ground and allowing the retrieval of microphysical properties practically close to the surface.

  4. Virtual endoscopy in neurosurgery: a review.

    PubMed

    Neubauer, André; Wolfsberger, Stefan

    2013-01-01

    Virtual endoscopy is the computerized creation of images depicting the inside of patient anatomy reconstructed in a virtual reality environment. It permits interactive, noninvasive, 3-dimensional visual inspection of anatomical cavities or vessels. This can aid in diagnostics, potentially replacing an actual endoscopic procedure, and help in the preparation of a surgical intervention by bridging the gap between plain 2-dimensional radiologic images and the 3-dimensional depiction of anatomy during actual endoscopy. If not only the endoscopic vision but also endoscopic handling, including realistic haptic feedback, is simulated, virtual endoscopy can be an effective training tool for novice surgeons. In neurosurgery, the main fields of the application of virtual endoscopy are third ventriculostomy, endonasal surgery, and the evaluation of pathologies in cerebral blood vessels. Progress in this very active field of research is achieved through cooperation between the technical and the medical communities. While the technology advances and new methods for modeling, reconstruction, and simulation are being developed, clinicians evaluate existing simulators, steer the development of new ones, and explore new fields of application. This review introduces some of the most interesting virtual reality systems for endoscopic neurosurgery developed in recent years and presents clinical studies conducted either on areas of application or specific systems. In addition, benefits and limitations of single products and simulated neuroendoscopy in general are pointed out.

  5. Minimalism in Art, Medical Science and Neurosurgery.

    PubMed

    Ökten, Ali İhsan

    2016-12-21

    The word ''minimalism'' is a word derived from French the word ''minimum''. Whereas the lexical meaning of minimum is ''the least or the smallest quantity necessary for something'', its expression in mathematics can be described as ''the lowest step a variable number can descend, least, minimal''. Minimalism, which advocates an extreme simplicity of the artistic form, is a current in modern art and music whose origins go to 1960s and which features simplicity and objectivity. Although art, science and philosophy are different disciplines, they support each other from time to time, sometimes they intertwine and sometimes they copy each other. A periodic schools or teaching in one of them can take the others into itself, so, they proceed on their ways empowering each other. It is also true for the minimalism in art and the minimal invasive surgical approaches in science. Concepts like doing with less, avoiding unnecessary materials and reducing the number of the elements in order to increase the effect in the expression which are the main elements of the minimalism in art found their equivalents in medicine and neurosurgery. Their equivalents in medicine or neurosurgery have been to protect the physical integrity of the patient with less iatrogenic injury, minimum damage and the same therapeutic effect in the most effective way and to enable the patient to regain his health in the shortest span of time.

  6. Neuromuscular Functions on Experimental Acute Methanol Intoxication

    PubMed Central

    Moral, Ali Reşat; Çankayalı, İlkin; Sergin, Demet; Boyacılar, Özden

    2015-01-01

    Objective The incidence of accidental or suicidal ingestion of methyl alcohol is high and methyl alcohol intoxication has high mortality. Methyl alcohol intoxication causes severe neurological sequelae and appears to be a significant problem. Methyl alcohol causes acute metabolic acidosis, optic neuropathy leading to permanent blindness, respiratory failure, circulatory failure and death. It is metabolised in the liver, and its metabolite formic acid has direct toxic effects, causing oxidative stress, mitochondrial damage and increased lipid peroxidation associated with the mechanism of neurotoxicity. Methanol is known to cause acute toxicity of the central nervous system; however, the effects on peripheral neuromuscular transmission are unknown. In our study, we aimed to investigate the electrophysiological effects of experimentally induced acute methanol intoxication on neuromuscular transmission in the early period (first 24 h). Methods After approval by the Animal Experiment Ethics Committee of Ege University, the study was carried out on 10 Wistar rats, each weighing about 200 g. During electrophysiological recordings and orogastric tube insertion, the rats were anaesthetised using intra-peritoneal (IP) injection of ketamine 100 mg kg−1 and IP injection of xylazine 10 mg kg−1. The rats were given 3 g kg−1 methyl alcohol by the orogastric tube. Electrophysiological measurements from the gastrocnemius muscle were compared with baseline. Results Latency measurements before and 24 h after methanol injection were 0.81±0.11 ms and 0.76±0.12 ms, respectively. CMAP amplitude measurements before and 24 h after methanol injection were 9.85±0.98 mV and 9.99±0.40 mV, respectively. CMAP duration measurements before and 24 h after methanol injection were 9.86±0.03 ms and 9.86±0.045 ms, respectively. Conclusion It was concluded that experimental methanol intoxication in the acute phase (first 24 h) did not affect neuromuscular function. PMID:27366524

  7. Experimental Fracture Measurements of Functionally Graded Materials

    NASA Astrophysics Data System (ADS)

    Carpenter, Ray Douglas

    The primary objective of this research was to extend established fracture toughness testing methods to a new class of engineering materials known as functionally graded materials (FGMs). Secondary goals were to compare experimental results to those predicted by finite element models and to provide fracture test results as feedback toward optimizing processing parameters for the in-house synthesis of a MoSi2/SiC FGM. Preliminary experiments were performed on commercially pure (CP) Ti and uniform axial tensile tests resulted in mechanical property data including yield strength, 268 MPa, ultimate tensile strength, 470 MPa and Young's modulus, 110 GPa. Results from 3-point bending fracture experiments on CP Ti demonstrated rising R-curve behavior and experimentally determined JQ fracture toughness values ranged between 153 N/mm and 254 N/mm. Similar experimental protocols were used for fracture experiments on a 7- layered Ti/TiB FGM material obtained from Cercom in Vista, California. A novel technique for pre-cracking in reverse 4-point bending was developed for this ductile/brittle FGM material. Fracture test results exhibited rising R-curve behavior and estimated JQ fracture toughness values ranged from 0.49 N/mm to 2.63 N/mm. A 5- layered MoSi2/SiC FGM was synthesized using spark plasma sintering (SPS). Samples of this material were fracture tested and the results again exhibited a rising R-curve with KIC fracture toughness values ranging from 2.7 MPa-m1/2 to 6.0 MPa-m1/2. Finite Element Models predicted rising R-curve behavior for both of the FGM materials tested. Model results were in close agreement for the brittle MoSi2/SiC FGM. For the relatively more ductile Ti/TiB material, results were in close agreement at short crack lengths but diverged at longer crack lengths because the models accounted for fracture toughening mechanisms at the crack tip but not those acting in the crack wake.

  8. Development and Evaluation of a Registration Methodology for Information-Guided Precision Robotic Laser Neurosurgery System

    NASA Astrophysics Data System (ADS)

    Nakamura, Ryoichi; Hara, Mikiko; Omori, Shigeru; Uematsu, Miyuki; Umezu, Mitsuo; Muragaki, Yoshihiro; Iseki, Hiroshi

    To establish safe, precise, and minimally invasive surgery, Computer Aided Surgery (CAS) systems, such as intra-operative imaging and navigation system to detect the location of the target of therapy, and surgical robot system, are very powerful tools. There is strong need to combine these CAS systems for fusion of advanced diagnosis and treatment technologies. In this paper, we introduce our new method to register the intraoperative imaging information, robotic surgery system, and patient using surgical navigation system. Using our Open-MRI navigation system and laser surgery system for neurosurgery, we can make registration between these system and patient precisely. The experimental result shows that the error on the registration between image data and the laser surgery system is low enough to fulfill the requirement of laser surgery system in the use of high-resolution image data. This system realizes the safe, precise and minimally invasive neurosurgery by the combination of intra-operative diagnosis and advanced therapeutic device.

  9. Comprehensive review on rhino-neurosurgery

    PubMed Central

    Hosemann, Werner; Schroeder, Henry W.S.

    2015-01-01

    In the past 2 decades, an innovative and active field of surgical collaboration has been evolved and established combining the expertise of neurosurgery and rhinosurgery in the endonasal treatment of different lesions affecting the anterior skull base together with the adjacent intranasal and intradural areas. Important prerequisites for this development were improvements of technical devices, definitions of transnasal surgical corridors, and approvements in endonasal reconstructions, e.g. by use of pedicled nasal mucosal flaps. Due to these improvements, the rate of perioperative infectious complications remained acceptable. Interdisciplinary surgical teams (4-hands-2-minds) have been established constituting specialized centers of “rhino-neurosurgery”. With growing expertise of these groups, it could be shown that oncological results and perioperative complications were comparable to traditional surgery while at the same time the patients’ morbidity could be reduced. The present review encompasses the recent literature focusing on the development, technical details, results, and complications of “rhino-neurosurgery”. PMID:26770276

  10. Options for perioperative pain management in neurosurgery

    PubMed Central

    Vadivelu, Nalini; Kai, Alice M; Tran, Daniel; Kodumudi, Gopal; Legler, Aron; Ayrian, Eugenia

    2016-01-01

    Moderate-to-severe pain following neurosurgery is common but often does not get attention and is therefore underdiagnosed and undertreated. Compounding this problem is the traditional belief that neurosurgical pain is inconsequential and even dangerous to treat. Concerns about problematic effects associated with opioid analgesics such as nausea, vomiting, oversedation, and increased intracranial pressure secondary to elevated carbon dioxide tension from respiratory depression have often led to suboptimal postoperative analgesic strategies in caring for neurosurgical patients. Neurosurgical patients may have difficulty or be incapable of communicating their need for analgesics due to neurologic deficits, which poses an additional challenge. Postoperative pain control should be a priority, because pain adversely affects recovery and patient outcomes. Inconsistent practices and the quality of current analgesic strategies for neurosurgical patients still leave room for improvement. Given the complexity of postoperative pain management for these patients, multimodal strategies are often required to optimize pain control and at the same time limit undesired side effects. PMID:26929661

  11. Life and Medical Ethics in Pediatric Neurosurgery

    PubMed Central

    YAMASAKI, Mami

    2017-01-01

    Ethical issues in the field of pediatric neurosurgery, including prenatal diagnosis, palliative care for children with an intractable serious disease, and medical neglect, are discussed. An important role of medicine is to offer every possible treatment to a patient. However, it also is the responsibility of medicine to be conscious of its limitations, and to help parents love and respect a child who suffers from an incurable disease. When dealing with cases of medical neglect and palliative care for an incurable disease, it is critical to diagnose the child’s condition accurately and evaluate the outcome. However, to treat or not to treat also depends on the medical resources and social-economic status of the community, the parents’ religion and philosophy, the policies of the institutions involved, and the limits of medical science. Moral dilemmas will continue to be addressed as medical progress yields treatments for untreatable diseases in the future. PMID:28025426

  12. [The history of Spanish neurosurgery: the Valencian school: J.J. Barcia Goyanes].

    PubMed

    Barcia-Mariño, Carlos; Rodríguez-Mena, Ruben

    2013-01-01

    Professor Juan José Barcia-Goyanes started neurosurgical practice from anatomy and neuropsychiatry in response to a vacancy at a department known as "Nervous diseases", in 1931 at Hospital General in Valencia, Spain. Since the first intervention, based on the methods and surgical instruments already used in Europe and the U.S.A., the neurosurgical practice became the mainstay of the department, from which other auxiliary specialties emerged, such as neuroradiology, neurophysiology, neuropathology and also new techniques such as stereotactic surgery, functional neurosurgery and palencephalography. This year, the department celebrates its 80th anniversary. The broad spectrum of Prof. Barcia's scientific work included fields like neurology, neurosurgery and psychiatry, as well as anthropology, medical thought, history of medicine, morphology and history of anatomical language in his work "Onomatologica anatomica nova", in addition to an interesting poetic work. He was a founding member of the Luso-Spanish Neurosurgical Society and the Neurosurgical Society of Levante.

  13. Medieval neurosurgery: contributions from the Middle East, Spain, and Persia.

    PubMed

    Rahimi, Scott Y; McDonnell, Dennis E; Ahmadian, Amir; Vender, John R

    2007-01-01

    Modern neurological and spinal surgical techniques have been developed on the foundations established by predecessors. Modern 21st century neurosurgery begins in the Babylonian period, with the Edwin Smith papyrus. Throughout history, periods of enlightenment have resulted in advances in knowledge and understanding that have served as stepping stones for generations to come. As in other fields, in neurosurgery these periods of "enlightenment" have occurred in a variety of civilizations and time periods.

  14. Introduction: military neurosurgery, past and present.

    PubMed

    Klimo, Paul; Ragel, Brian T

    2010-05-01

    For a physician has the worth of many other warriors, both for the excision of arrows and for the administration of soothing drugs. Homer, Iliad XI.514-515 Ever since armed conflict has been used as a means to settle disputes among men, there have been those who have been tasked to mend the wounds that ravage a soldier's body from the weapons of war. The Iliad portrays the pivotal 10th year of the legendary Trojan War, during which a schism in the Greek leadership prolongs the extended siege of the city of Troy. In the midst of this martial epic come the lines quoted above, quietly attesting to the value of the military physician, even under the crude conditions of the Greek Dark Age. They are uttered by Idomeneus, one of the foremost Greeks, when he is enjoining one of his comrades, Nestor, to rescue the injured Greek physician Machaon and take him back from the line to treat his wounds. He is afraid that Machaon will be captured by the Trojans, a loss far greater than that of any other single warrior. Duty to country has helped shape the careers of many neurosurgeons, including iconic US figures such as Harvey Cushing and Donald Matson. This issue of Neurosurgical Focus celebrates the rich history of military neurosurgery from the wars of yesterday to the conflicts of today. We have been humbled by the tremendous response to this topic. The 25 articles within this issue will provide the reader with both a broad and an in-depth look at the many facets of military neurosurgery. We have attempted to group articles based on their predominant topic. We also encourage our audience to read other recently published articles. The first 8 articles relate to the current conflicts in Afghanistan and Iraq. The lead article, written by Randy Bell and colleagues from the National Naval Medical Center and Walter Reed Army Medical Center, discusses what is arguably one of the most important contributions by military neurosurgeons from these 2 conflicts: the rapid and aggressive

  15. Bulgarian military neurosurgery: from Warsaw Pact to the North Atlantic Treaty Organization.

    PubMed

    Enchev, Yavor; Eftimov, Tihomir

    2010-05-01

    After 45 years as a closest ally of the Soviet Union in the Warsaw Pact, founded mainly against the US and the Western Europe countries, and 15 years of democratic changes, since 2004 Bulgaria has been a full member of NATO and an equal and trusted partner of its former enemies. The unprecedented transformation has affected all aspects of the Bulgarian society. As a function of the Bulgarian Armed Forces, Bulgarian military medicine and in particular Bulgarian military neurosurgery is indivisibly connected with their development. The history of Bulgarian military neurosurgery is the history of the transition from the Union of Soviet Socialist Republics military system and military medicine to NATO standards in every aspect. The career of the military neurosurgeon in Bulgaria is in many ways similar to that of the civilian neurosurgeon, but there are also many peculiarities. The purpose of this study was to outline the background and the history of Bulgarian military neurosurgery as well as its future trends in the conditions of world globalization.

  16. Aura of technology and the cutting edge: a history of lasers in neurosurgery.

    PubMed

    Ryan, Robert W; Spetzler, Robert F; Preul, Mark C

    2009-09-01

    In this historical review the authors examine the important developments that have led to the availability of laser energy to neurosurgeons as a unique and sometimes invaluable tool. They review the physical science behind the function of lasers, as well as how and when various lasers based on different lasing mediums were discovered. They also follow the close association between advances in laser technology and their application in biomedicine, from early laboratory experiments to the first clinical experiences. Because opinions on the appropriate role of lasers in neurosurgery vary widely, the historical basis for some of these views is explored. Initial enthusiasm for a technology that appears to have innate advantages for safe resections has often given way to the strict limitations and demands of the neurosurgical operating theater. However, numerous creative solutions to improve laser delivery, power, safety, and ergonomics demonstrate the important role that technological advances in related scientific fields continue to offer neurosurgery. Benefiting from the most recent developments in materials science, current CO(2) laser delivery systems provide a useful addition to the neurosurgical armamentarium when applied in the correct circumstances and reflect the important historical advances that come about from the interplay between neurosurgery and technology.

  17. Nonlinear optical imaging: toward chemical imaging during neurosurgery

    NASA Astrophysics Data System (ADS)

    Meyer, Tobias; Dietzek, Benjamin; Krafft, Christoph; Romeike, Bernd F. M.; Reichart, Rupert; Kalff, Rolf; Popp, Jürgen

    2011-03-01

    Tumor recognition and precise tumor margin detection presents a central challenge during neurosurgery. In this contribution we present our recent all-optical approach to tackle this problem. We introduce various nonlinear optical techniques, such as coherent anti-Stokes Raman scattering (CARS), second-harmonic generation (SHG) and two-photon fluorescence (TPEF), to study the morphology and chemical composition of (ex vivo) brain tissue. As the experimental techniques presented are contact-free all-optical techniques, which do not rely on the administration of external (fluorescence) labels, we anticipate that their implementation into surgical microscopes will provide significant advantages of intraoperative tumor diagnosis. In this contribution an introduction to the different optical spectroscopic methods will be presented and their implementation into a multimodal microscopic setup will be discussed. Furthermore, we will exemplify their application to brain tissue, i.e. both pig brain as a model for healthy brain tissue and human brain samples taken from surgical procedures. The data to be discussed show the capability of a joint CARS/SHG/TPEF multimodal imaging approach in highlighting various aspects of tissue morphochemistry. The consequences of this microspectroscopic potential, when combined with the existing technology of surgical microscopes, will be discussed.

  18. Neurosurgery of the future: Deep brain stimulations and manipulations.

    PubMed

    Nicolaidis, Stylianos

    2017-04-01

    Important advances are afoot in the field of neurosurgery-particularly in the realms of deep brain stimulation (DBS), deep brain manipulation (DBM), and the newly introduced refinement "closed-loop" deep brain stimulation (CLDBS). Use of closed-loop technology will make both DBS and DBM more precise as procedures and will broaden their indications. CLDBS utilizes as feedback a variety of sources of electrophysiological and neurochemical afferent information about the function of the brain structures to be treated or studied. The efferent actions will be either electric, i.e. the classic excitatory or inhibitory ones, or micro-injection of such things as neural proteins and transmitters, neural grafts, implants of pluripotent stem cells or mesenchymal stem cells, and some variants of gene therapy. The pathologies to be treated, beside Parkinson's disease and movement disorders, include repair of neural tissues, neurodegenerative pathologies, psychiatric and behavioral dysfunctions, i.e. schizophrenia in its various guises, bipolar disorders, obesity, anorexia, drug addiction, and alcoholism. The possibility of using these new modalities to treat a number of cognitive dysfunctions is also under consideration. Because the DBS-CLDBS technology brings about a cross-fertilization between scientific investigation and surgical practice, it will also contribute to an enhanced understanding of brain function.

  19. Neurosurgery in rural Nigeria: A prospective study

    PubMed Central

    Rabiu, Taopheeq Bamidele; Komolafe, Edward Oluwole

    2016-01-01

    Background: Africa has very few neurosurgeons. These are almost exclusively in urban centers. Consequently, people in rural areas, most of the African population, have poor or no access to neurosurgical care. We have recently pioneered rural neurosurgery in Nigeria. Objectives: This report details our initial experiences and the profile of neurosurgical admissions in our center. Methods: A prospective observational study of all neurosurgical patients managed at a rural tertiary health institution in Nigeria from December 2010 to May 2012 was done. Simple descriptive data analysis was performed. Results: A total of 249 males (75.2%) and 82 females (24.8%) were managed. The median age was 37 years (range: Day of birth – 94 years). Trauma was the leading cause of presentation with 225 (68.0%) and 35 (10.6%) having sustained head and spinal injuries, respectively. Operative intervention was performed in 54 (16.3%). Twenty-four (7.2%) patients discharged against medical advice, mostly for economic reasons. Most patients (208, 63.4%) had satisfactory outcome while 30 (9.1%) died. Conclusion: Trauma is the leading cause of rural neurosurgical presentations. There is an urgent need to improve access to adequate neurosurgical care in the rural communities. PMID:27695224

  20. Prophylactic antibiotics and anticonvulsants in neurosurgery.

    PubMed

    Ratilal, B; Sampaio, C

    2011-01-01

    The prophylactic administration of antibiotics to prevent infection and the prophylactic administration of anticonvulsants to prevent first seizure episodes are common practice in neurosurgery. If prophylactic medication therapy is not indicated, the patient not only incurs the discomfort and the inconvenience resulting from drug treatment but is also unnecessarily exposed to adverse drug reactions, and incurs extra costs. The main situations in which prophylactic anticonvulsants and antibiotics are used are described and those situations we found controversial in the literature and lack further investigation are identified: anticonvulsants for preventing seizures in patients with chronic subdural hematomas, antiepileptic drugs for preventing seizures in those suffering from brain tumors, antibiotic prophylaxis for preventing meningitis in patients with basilar skull fractures, and antibiotic prophylaxis for the surgical introduction of intracranial ventricular shunts.In the following we present systematic reviews of the literature in accordance with the standard protocol of The Cochrane Collaboration to evaluate the effectiveness of the use of these prophylactic medications in the situations mentioned. Our goal was to efficiently integrate valid information and provide a basis for rational decision-making.

  1. The functions of language: an experimental study.

    PubMed

    Redhead, Gina; Dunbar, R I M

    2013-08-14

    We test between four separate hypotheses (social gossip, social contracts, mate advertising and factual information exchange) for the function(s) of language using a recall paradigm. Subjects recalled the social content of stories (irrespective of whether this concerned social behavior, defection or romantic events) significantly better than they did ecological information. Recall rates were no better on ecological stories if they involved flamboyant language, suggesting that, if true, Miller's "Scheherazade effect" may not be independent of content. One interpretation of these results might be that language evolved as an all-purpose social tool, and perhaps acquired specialist functions (sexual advertising, contract formation, information exchange) at a later date through conventional evolutionary windows of opportunity.

  2. The genesis of neurosurgery and the evolution of the neurosurgical operative environment: part I-prehistory to 2003.

    PubMed

    Liu, Charles Y; Apuzzo, Michael L J

    2003-01-01

    Despite its singular importance, little attention has been given to the neurosurgical operative environment in the scientific and medical literature. This article focuses attention on the development of neurosurgery and the parallel emergence of its operative setting. The operative environment has, to a large extent, defined the "state of the art and science" of neurosurgery, which is now undergoing rapid reinvention. During the course of its initial invention, major milestones in the development of neurosurgery have included the definition of anatomy, consolidation of a scientific basis, and incorporation of the practicalities of anesthesia and antisepsis and later operative technical adjuvants for further refinement of action and minimalism. The progress, previously long and laborious in emergence, is currently undergoing rapid evolution. Throughout its evolution, the discipline has assimilated the most effective tools of modernity into the operative environment, leading eventually to the entity known as the operating room. In the decades leading to the present, progressive minimalization of manipulation and the emergence of more refined operative definition with increasing precision are evident, with concurrent miniaturization of attendant computerized support systems, sensors, robotic interfaces, and imaging devices. These developments over time have led to the invention of neurosurgery and the establishment of the current state-of-the-art neurosurgical operating room as we understand it, and indeed, to a broader definition of the entity itself. To remain current, each neurosurgeon should periodically reconsider his or her personal operative environment and its functional design with reference to modernity of practice as currently defined.

  3. Shining light on neurosurgery diagnostics using Raman spectroscopy.

    PubMed

    Broadbent, Brandy; Tseng, James; Kast, Rachel; Noh, Thomas; Brusatori, Michelle; Kalkanis, Steven N; Auner, Gregory W

    2016-10-01

    Surgical excision of brain tumors provides a means of cytoreduction and diagnosis while minimizing neurologic deficit and improving overall survival. Despite advances in functional and three-dimensional stereotactic navigation and intraoperative magnetic resonance imaging, delineating tissue in real time with physiological confirmation is challenging. Raman spectroscopy is a promising investigative and diagnostic tool for neurosurgery, which provides rapid, non-destructive molecular characterization in vivo or in vitro for biopsy, margin assessment, or laboratory uses. The Raman Effect occurs when light temporarily changes a bond's polarizability, causing change in the vibrational frequency, with a corresponding change in energy/wavelength of the scattered photon. The recorded inelastic scattering results in a "fingerprint" or Raman spectrum of the constituent under investigation. The amount, location, and intensity of peaks in the fingerprint vary based on the amount of vibrational bonds in a molecule and their ensemble interactions with each other. Distinct differences between various pathologic conditions are shown as different intensities of the same peak, or shifting of a peak based on the binding conformation. Raman spectroscopy has potential for integration into clinical practice, particularly in distinguishing normal and diseased tissue as an adjunct to standard pathologic diagnosis. Further, development of fiber-optic Raman probes that fit through the instrument port of a standard endoscope now allows researchers and clinicians to utilize spectroscopic information for evaluation of in vivo tissue. This review highlights the need for such an instrument, summarizes neurosurgical Raman work performed to date, and discusses the future applications of neurosurgical Raman spectroscopy.

  4. Pharmacologic modulation of experimental postischemic hepatic function.

    PubMed Central

    Ontell, S J; Makowka, L; Trager, J; Mazzaferro, V; Ove, P; Starzl, T E

    1989-01-01

    The present study evaluated and compared the effects of SRI 63-441, a potent platelet activating factor antagonist, superoxide dismutase (SOD), an oxygen free radical scavenger, and ibuprofen, a cyclooxygenase inhibitor on hepatic function after 90 minutes of warm ischemia. After warm ischemia, livers were harvested and underwent 90 minutes of warm, oxygenated, sanguinous perfusion on an isolated liver perfusion apparatus. Pretreatment of donor animals with 20 mg/kg intravenous (I.V.) SRI 63-441 5 minutes before induction of total hepatic ischemia resulted in significantly increased bile production, a significant decrease in transaminase release, and a higher tissue adenosine triphosphate (ATP) content when compared with ischemic nontreated controls. SOD resulted in improved bile production and decreased transaminase liberation only when present in the perfusate at the time of in vitro reperfusion. Ibuprofen did not improve postischemic hepatic function in this model. Electron microscopy revealed patchy hepatocellular vacuolization with an intact sinusoidal endothelium in all ischemic livers. However, the degree of damage was less severe in the livers from those rats pretreated with 20 mg/kg SRI 63-441. This study demonstrates that SRI 63-441 pretreatment significantly reduces hepatic warm ischemic injury, and in the present model, appears superior to two other agents that have been advanced in the treatment of ischemic injury. The use of such agents singly or in combinations have important implications as regards gaining a better understanding of the basic mechanisms in organ ischemia, and moreover, for therapeutic applications in organ ischemia and preservation. Images Fig. 3. Figs. 6A-C. Figs. 6A-C. Fig. 7. Figs. 8A-C. Figs. 8A-C. PMID:2916864

  5. Augmented reality in neurosurgery: a systematic review.

    PubMed

    Meola, Antonio; Cutolo, Fabrizio; Carbone, Marina; Cagnazzo, Federico; Ferrari, Mauro; Ferrari, Vincenzo

    2016-05-07

    Neuronavigation has become an essential neurosurgical tool in pursuing minimal invasiveness and maximal safety, even though it has several technical limitations. Augmented reality (AR) neuronavigation is a significant advance, providing a real-time updated 3D virtual model of anatomical details, overlaid on the real surgical field. Currently, only a few AR systems have been tested in a clinical setting. The aim is to review such devices. We performed a PubMed search of reports restricted to human studies of in vivo applications of AR in any neurosurgical procedure using the search terms "Augmented reality" and "Neurosurgery." Eligibility assessment was performed independently by two reviewers in an unblinded standardized manner. The systems were qualitatively evaluated on the basis of the following: neurosurgical subspecialty of application, pathology of treated lesions and lesion locations, real data source, virtual data source, tracking modality, registration technique, visualization processing, display type, and perception location. Eighteen studies were included during the period 1996 to September 30, 2015. The AR systems were grouped by the real data source: microscope (8), hand- or head-held cameras (4), direct patient view (2), endoscope (1), and X-ray fluoroscopy (1) head-mounted display (1). A total of 195 lesions were treated: 75 (38.46 %) were neoplastic, 77 (39.48 %) neurovascular, and 1 (0.51 %) hydrocephalus, and 42 (21.53 %) were undetermined. Current literature confirms that AR is a reliable and versatile tool when performing minimally invasive approaches in a wide range of neurosurgical diseases, although prospective randomized studies are not yet available and technical improvements are needed.

  6. Neurosurgery in the realm of 10(-9), Part 2: applications of nanotechnology to neurosurgery--present and future.

    PubMed

    Elder, James B; Liu, Charles Y; Apuzzo, Michael L J

    2008-02-01

    Neurosurgery in the future will witness an increasing influx of novel technologies, many of which will be based on developments in the emerging science of nanotechnology. Additionally, the continued trend in medicine toward minimally invasive diagnostic and surgical techniques will be aided by incorporation of applications of nanotechnology. Neurosurgeons of the future must facilitate the development of nanotechnology and nanomedicine in their clinical practice and research efforts to optimize patient benefit and facilitate scientific advancement. The fields of nanotechnology and nanomedicine remain in their infancy. Recently, however, the literature regarding nanoscience has rapidly expanded. This article is the second of two and provides a review of recent nanotechnology research relevant to clinical neurosurgery and neurology. The first article reviewed recent developments and issues in nanotechnology with a particular focus on applications to the neurosciences. This article also discusses current developments in nanotechnology and nanomedicine that may yield applications in neurosurgery in the future. Additional attention is given to other emerging technologies that are not truly nanotechnology, such as microelectromechanical systems, which will influence the future of medicine and neurosurgery. The goal is to provide the reader with a brief outline and description of some of the new developments in nanotechnology that may affect the clinical practice or operative experience of neurosurgeons. Continued innovation in nanotechnology presents novel opportunities for translation to the clinical arena. Neuroscience, neurology, and neurosurgery will be greatly affected by the influx of nanoscience and its applications. Through continued collaboration, physicians, scientists, and engineers will shape the futures of nanomedicine and nanoneurosurgery.

  7. Fast forwarding: the evolution of neurosurgery. The 2005 presidential address.

    PubMed

    Ratcheson, Robert A

    2005-10-01

    Despite the major social and economic reorganization of medical practice that has taken place during the past 40 years, neurosurgery-the most fascinating specialty in all of clinical medicine-has grown and prospered. Today, this specialty is poised for an era of spectacular advancement and improvement in care; however, significant problems with the potential to retard this growth face neurosurgery. Among these problems is the medical liability situation, which has the potential to destabilize neurosurgical practices and the current health care delivery system. Other issues facing neurosurgery include the potential for loss of the unique nature of the specialty through a conversion to shift-worker surgeons and increasing reliance on profit-seeking institutions for financial stability and liability protection. Lifestyle choices are of growing importance and currently discourage women from entering the field. With a growing knowledge base, there is the recognition that it may not be possible for most individuals to master all aspects of the specialty. There is continued confusion about manpower needs. In addition, some neurosurgeons are choosing to practice in ways that fail to meet the neurosurgeon's obligations to society. There is a growing number of neurosurgeons who dislike providing trauma coverage and there is the potential for some neurosurgeons to give up intracranial neurosurgery. The author believes that it is not competition that will improve the delivery of neurosurgical care and allow for continued growth, but cooperation, and that it will be possible to alleviate many of our problems through increased regionalization of neurosurgical care delivery. This proposal has the potential to promote the formation of neurosurgical teams, ameliorate the problem of physician fatigue, allow greater development of subspecialty skills, and ease the burden of trauma call. It should allow satisfactory solutions to lifestyle considerations and encourage more women to

  8. Government Medical College Trivandrum - Fifty years of Neurosurgery in Kerala state.

    PubMed

    Peethambaran, Anil Kumar; Chandran, Raj S

    2017-01-01

    The Department of Neurosurgery founded in the Trivandrum Medical College, Kerala, the first teaching hospital in Kerala state, is celebrating its 50th anniversary. The history of Neurosurgery in this Institute is synonymous with the history of Neurosurgery in the state as this was the first medical college to start a Neurosurgery department within the state.The students after undergoing their rigorous training in the department, went on to establish advanced neurosurgical centres throughout Kerala and in several other parts of the country. This article traces the illustrious history of the Department of Neurosurgery, Trivandrum Medical College and also of the eminent faculty members and residents, who helped in advancing the standards of Neurosurgery in the region as well as the rest of India. The Department of Neurosurgery was founded in the Trivandrum Medical College, Kerala, the first teaching hospital in Kerala state, in the year 1951, and is celebrating its 50th anniversary. The history of Neurosurgery in this Institute is synonymous with the history of Neurosurgery in the state as this was the first medical college to start a Neurosurgery department within the state.The students after undergoing their rigorous training in the department, went on to establish advanced neurosurgical centres throughout Kerala and in several other parts of the country. This article traces the illustrious history of the Department of Neurosurgery, Trivandrum Medical College and also of the eminent faculty members and residents, who helped in advancing the standards of Neurosurgery in the region as well as the rest of India.

  9. Recent Trends in Conducting School-Based Experimental Functional Analyses

    ERIC Educational Resources Information Center

    Carter, Stacy L.

    2009-01-01

    Demonstrations of school-based experimental functional analyses have received limited attention within the literature. School settings present unique practical and ethical concerns related to the implementation of experimental analyses which were originally developed within clinical settings. Recent examples have made definite contributions toward…

  10. Clinical and experimental results of photodynamic therapy in neurosurgery

    NASA Astrophysics Data System (ADS)

    Kostron, Herwig; Hochleitner, B. W.; Obwegeser, Alois; Seiwald, M.

    1995-03-01

    Since 1984, 58 patients bearing malignant brain tumors were treated 70 times with photodynamic treatment (PDT). The patient population consisted of 11 primary glioblastoma WHO grade IV, 39 recurrent glioblastomas, 3 malignant meningiomas, 3 recurrent melanomas, and 2 metastasis of carcinomas. The patients were sensitized with hematoporphyrin derivative (HPD) 2.5 mg/bodyweight 24 - 48 hours prior to craniotomy and tumor resection. The light-irradiation was performed by an Argon pumped dye laser (Aurora M) superficially and/or interstitially at a dose ranging up to 250 J/cm2. The median survival of primary glioblastomas was 19 months and for recurrent glioblastomas 7 months, respectively. Malignant meningiomas, as well as melanomas, did not benefit from PDT, whereas one patient with a metastasis of an adenocarcinoma is still recurrence free since 18 months, the other recurred after 6 months. HPD extractions of the tumor revealed significantly different concentrations among the various tumors, but also between identical histologies. The survival, however, did not correlate with the HPD concentration in the tumor. PDT prolongs median survival of primary glioblastomas significantly, and doubles the survival of recurrent high grade gliomas. Furthermore the treatment of recurrent low grade gliomas and metastasis to the brain are promising indications for PDT.

  11. Spinal neurosurgery with the head-mounted "Varioscope" microscope.

    PubMed

    Kuchta, J; Simons, P

    2009-05-01

    We present a preliminary report on the intra-operative use of a head-mounted microscope ("Varioscope" Leica HM500) in spinal neurosurgery. The Varioscope is a dynamic microscope mounted on a head-set. It weights 297 g and measures 73 x 120 x 63 mm (length x width x height). It offers an infinitely variable range of magnification from 3.6x to 7.2x. The working distance ranges from 300 to 600 mm. The field of view varies between 30-144 mm, depending on the selected enlargement factor and the working distance. In addition to the zoom function, the device offers a focus function (automatic or on demand). The optical elements for focus and zoom are located in two separate tubes which are mounted on a middle section containing the mechanical components as well as the receiver unit for the focussing elements. The lenses are adjusted by means of motor-driven push/pull cables. The autofocus works well in larger operative fields and a working distance between 30 and 60 cm. Nevertheless, when used in today's "keyhole" approaches, the autofocus is not helpful when operating in deep structures. Based on the satisfactory results achieved in our series, we can recommend the Varioscope, especially when no stationary microscope is available. The portable device can be packed in a suitcase and can travel with the consultant microsurgeon to different hospitals and distant units. The built-in video camera is ideal for patients, staff, assistant surgeons, and student education with real-time video monitoring of procedures from the microsurgeon's perspective. For daily microsurgery, we felt more comfortable with fixed, stationary operating microscopes.

  12. History of Neurosurgery at Postgraduate Institute of Medical Education and Research, Chandigarh.

    PubMed

    Gupta, Sunil K; Mukherjee, Kanchan K; Chhabra, Rajesh; Tripathi, Manjul

    2017-01-01

    The Department of Neurosurgery started functioning at the Postgraduate Institute of Medical Education and Research, Chandigarh in 1962 with the joining of Dr. Gulati. The department provides neurosurgical services primarily to the people of Chandigarh, Punjab, Haryana, Himachal Pradesh, Jammu and Kashmir as well as the neighbouring areas of Rajasthan, Uttar Pradesh and Uttarakhand. The infrastructure and subspecialties have been developed over the last 5 decades by the dedicated and tireless efforts of the faculty and residents. We attempt to chronicle the contributions of those who have served the department in the past.

  13. In touch with robotics: neurosurgery for the future.

    PubMed

    Nathoo, Narendra; Cavuşoğlu, M Cenk; Vogelbaum, Michael A; Barnett, Gene H

    2005-03-01

    The introduction of multiple front-end technologies during the past quarter century has generated an emerging futurism for the discipline of neurological surgery. Driven primarily by synergistic developments in science and engineering, neurosurgery has always managed to harness the potential of the latest technical developments. Robotics represents one such technology. Progress in development of this technology has resulted in new uses for robotic devices in our discipline, which are accompanied by new potential dangers and inherent risks. The recent surge in robot-assisted interventions in other disciplines suggests that this technology may be considered one of a spectrum of frontier technologies poised to fuel the development of neurosurgery and consolidate the era of minimalism. On a more practical level, if the introduction of robotics in neurosurgery proves beneficial, neurosurgeons will need to become facile with this technology and learn to harness its potential so that the best surgical results may be achieved in the least invasive manner. This article reviews the role of robotic technology in the context of neurosurgery.

  14. Cerenkov and radioluminescence imaging of brain tumor specimens during neurosurgery

    NASA Astrophysics Data System (ADS)

    Spinelli, Antonello Enrico; Schiariti, Marco P.; Grana, Chiara M.; Ferrari, Mahila; Cremonesi, Marta; Boschi, Federico

    2016-05-01

    We presented the first example of Cerenkov luminescence imaging (CLI) and radioluminescence imaging (RLI) of human tumor specimens. A patient with a brain meningioma localized in the left parietal region was injected with 166 MBq of Y90-DOTATOC the day before neurosurgery. The specimens of the tumor removed during surgery were imaged using both CLI and RLI using an optical imager prototype developed in our laboratory. The system is based on a cooled electron multiplied charge coupled device coupled with an f/0.95 17-mm C-mount lens. We showed for the first time the possibility of obtaining CLI and RLI images of fresh human brain tumor specimens removed during neurosurgery.

  15. A Bosphorus submarine passage and the reinvention of neurosurgery.

    PubMed

    Apuzzo, Michael L J; Pagán, Veronica M; Faccio, Rodrick; Liu, Charles Y

    2013-01-01

    One of the major themes characterizing the emergence of modern neurosurgery has been the concept of technology transfer and the application of a broad spectrum of revolutionary elements of technology from both physical and biological science. These transference applications are now apparent in modern neurosurgery as it is practiced on all continents of the globe. More than 3 decades ago, these ideas that now have come to fruition were in states of formulation. This article describes and further documents one such fertile cauldron of ideas and practical realities--the United States Navy Nuclear Submarine Service and its role and affect on the life and professional career of an academic neurosurgeon who was active in areas of progress as modernity was established for the early 21st century.

  16. [Operative neurosurgery: personal view and historical backgrounds (2) acoustic neurinoma].

    PubMed

    Yonekawa, Yasuhiro

    2006-12-01

    Microsurgical removal of acoustic neurinoma is still one of the challenging topics in neurosurgery in spite of the development of Gamma-knife or radiosurgery, with which small and moderate sized tumors can be treated. Surgical technique necessitates more expertise in dealing with larger tumors. In this report ongoing microsurgical standard technique for removal of acoustic neurinomas of approx. 3 cm (extrameatal) in diameter is presented along with its historical backgrounds and literature review with reported techniques used by experienced neurosurgeons. 1) Standard sitting position with head turned (30) and flexed (20) head, and not semisitting position. 2) retromastoid retrosigmoid osteoplastic craniotomy following a linear incision. Special mention is made on how to manage the air embolism inherent to the sitting position in which the use of fibrin glue to seal the air entrance is presented along with early detection. 3) Intracapsular enucleation after the dural incision and retraction of the biventer lobule with special emphasis on the infrequent anatomical course of the facial and vestibulocochlear nerves on the posterior wall of neurinomas. 4) Localizing the facial nerve and vestibulocochlear nerve at the pontine side, so that decision of preserving or sacrificing the latter in the course of surgery can be made from the viewpoint of hearing preservation and concentrate on facial nerve function. 5) Drilling away of the posterior meatal lip in which sufficient drilling away should be performed to minimize opening of the posterior semicircular canal and that of mastoid cells. Complete sealing of either is necessary to prevent hearing loss or CSF rhinorrhoe. 6) Reduction of remaining tumor-capsule volume by sharp dissection or bipolar cutting, using intraoperative EMG-stimulation which identifies the presence of flattened facial nerve fibers on the capsule. Presence tiny remnant of the tumor capsule attached to the nerve bundles just before the entrance of

  17. Josef Klingler's models of white matter tracts: influences on neuroanatomy, neurosurgery, and neuroimaging.

    PubMed

    Agrawal, Abhishek; Kapfhammer, Josef P; Kress, Annetrudi; Wichers, Hermann; Deep, Aman; Feindel, William; Sonntag, Volker K H; Spetzler, Robert F; Preul, Mark C

    2011-08-01

    During the 1930s, white matter tracts began to assume relevance for neurosurgery, especially after Cajal's work. In many reviews of white matter neurobiology, the seminal contributions of Josef Klingler (1888-1963) and their neurological applications have been overlooked. In 1934 at the University of Basel under Eugen Ludwig, Klingler developed a new method of dissection based on a freezing technique for brain tissue that eloquently revealed the white matter tracts. Klingler worked with anatomists, surgeons, and other scientists, and his models and dissections of white matter tracts remain arguably the most elegant ever created. He stressed 3-dimensional anatomic relationships and laid the foundation for defining mesial temporal, limbic, insular, and thalamic fiber and functional relationships and contributed to the potential of stereotactic neurosurgery. Around 1947, Klingler was part of a Swiss-German group that independently performed the first stereotactic thalamotomies, basing their targeting and logic on Klingler's white matter studies, describing various applications of stereotaxy and showing Klingler's work integrated into a craniocerebral topographic system for targeting with external localization of eloquent brain structures and stimulation of deep thalamic nuclei. Klingler's work has received renewed interest because it is applicable for correlating the results of the fiber-mapping paradigms from diffusion tensor imaging to actual anatomic evidence. Although others have described white matter tracts, none have had as much practical impact on neuroscience as Klinger's work. More importantly, Josef Klingler was an encouraging mentor, influencing neurosurgeons, neuroscientists, and brain imaging for more than three quarters of a century.

  18. Using experimental evolution to probe molecular mechanisms of protein function.

    PubMed

    Fischer, Marlies; Kang, Mandeep; Brindle, Nicholas Pj

    2016-02-01

    Directed evolution is a powerful tool for engineering protein function. The process of directed evolution involves iterative rounds of sequence diversification followed by assaying activity of variants and selection. The range of sequence variants and linked activities generated in the course of an evolution are a rich information source for investigating relationships between sequence and function. Key residue positions determining protein function, combinatorial contributors to activity and even potential functional mechanisms have been revealed in directed evolutions. The recent application of high throughput sequencing substantially increases the information that can be retrieved from directed evolution experiments. Combined with computational analysis this additional sequence information has allowed high-resolution analysis of individual residue contributions to activity. These developments promise to significantly enhance the depth of insight that experimental evolution provides into mechanisms of protein function.

  19. The historical origin of the term "meningioma" and the rise of nationalistic neurosurgery.

    PubMed

    Barthélemy, Ernest Joseph; Sarkiss, Christopher A; Lee, James; Shrivastava, Raj K

    2016-11-01

    "tumeurs cancéreuses de la duremère," and the work of histopathologists, such as Hermann Lebert, who were influenced by Pasteur's germ theory and by Bernard's experimental medicine. The final development of the meningioma nomenclature corresponded to the rise of American neurosurgery as a formal academic discipline. This historical period of growth is chronicled in Cushing's text Meningiomas, and it set the scientific stage for the modern developments in meningioma research and surgery that are conducted and employed today.

  20. Highly cited publications in pediatric neurosurgery: part 2

    PubMed Central

    Khan, Nickalus R.; Auschwitz, Tyler; McAbee, Joseph H.; Boop, Frederick A.; Klimo, Paul

    2015-01-01

    Purpose Citation counting can be used to evaluate the impact an article has made on its discipline. This study characterizes the most cited articles related to clinical pediatric neurosurgery as of July 2013. Methods A list of search terms was computed using Thomson Reuters Web of Science® (WOS) to capture the 100 most cited articles in the overall literature and the top 50 articles from 2002 to 2012 related to clinical pediatric neurosurgery from non-dedicated pediatric neurosurgical journals. The following information was recorded for each article: number of authors, country of origin, citation count adjusted for number of years in print, topic, and level of evidence. Results The 100 most cited articles appeared in 44 journals. Publication dates ranged from 1986 to 2008; two were class 1 evidence, nine class 2, 26 class 3, and 52 class 4. Citations ranged from 90 to 321 (mean=131); average time-adjusted citation count was 10. The 50 most cited articles from 2002 to 2012 appeared in 31 journals; four were class 2 evidence, 15 class 3, and 21 class 4. Citations ranged from 68 to 245 (mean=103); average time-adjusted citation count was 13. Conclusion Overall, papers from non-pediatric neurosurgical journals had higher citation counts and improved level of evidence grades compared to articles from pediatric neurosurgical periodicals. An original paper related to clinical pediatric neurosurgery in a non-pediatric neurosurgical journal having a total citation count of 100–150 or more and an average citation count of 10–15 per year or more can be considered a high-impact publication. PMID:24113776

  1. Publication misrepresentation among neurosurgery residency applicants: an increasing problem.

    PubMed

    Kistka, Heather M; Nayeri, Arash; Wang, Li; Dow, Jamie; Chandrasekhar, Rameela; Chambless, Lola B

    2016-01-01

    OBJECT Misrepresentation of scholarly achievements is a recognized phenomenon, well documented in numerous fields, yet the accuracy of reporting remains dependent on the honor principle. Therefore, honest self-reporting is of paramount importance to maintain scientific integrity in neurosurgery. The authors had observed a trend toward increasing numbers of publications among applicants for neurosurgery residency at Vanderbilt University and undertook this study to determine whether this change was a result of increased academic productivity, inflated reporting, or both. They also aimed to identify application variables associated with inaccurate citations. METHODS The authors retrospectively reviewed the residency applications submitted to their neurosurgery department in 2006 (n = 148) and 2012 (n = 194). The applications from 2006 were made via SF Match and those from 2012 were made using the Electronic Residency Application Service. Publications reported as "accepted" or "in press" were verified via online search of Google Scholar, PubMed, journal websites, and direct journal contact. Works were considered misrepresented if they did not exist, incorrectly listed the applicant as first author, or were incorrectly listed as peer reviewed or published in a printed journal rather than an online only or non-peer-reviewed publication. Demographic data were collected, including applicant sex, medical school ranking and country, advanced degrees, Alpha Omega Alpha membership, and USMLE Step 1 score. Zero-inflated negative binomial regression was used to identify predictors of misrepresentation. RESULTS Using univariate analysis, between 2006 and 2012 the percentage of applicants reporting published works increased significantly (47% vs 97%, p < 0.001). However, the percentage of applicants with misrepresentations (33% vs 45%) also increased. In 2012, applicants with a greater total of reported works (p < 0.001) and applicants from unranked US medical schools (those not

  2. 3D localization of ferromagnetic probes for small animal neurosurgery.

    PubMed

    Heinig, Maximilian; Schlaefer, Alexander; Schweikard, Achim

    2010-01-01

    We present the design, setup and results for a magnetic navigation system for small animal stereotactic neurosurgery. Our system tracks the position of thin (diameter 0.5 mm), magnetized ferromagnetic probes inserted into brains of small animals, e.g. rats, for electrophysiological recordings. It is used in combination with the spherical assistant for stereotactic surgery (SASSU) robot to obtain online feedback of the probe's position. Navigation is based only on the static magnetic field generated by the probes thus no external excitation or wires are needed.

  3. Automatic trajectory planning of DBS neurosurgery from multi-modal MRI datasets.

    PubMed

    Bériault, Silvain; Al Subaie, Fahd; Mok, Kelvin; Sadikot, Abbas F; Pike, G Bruce

    2011-01-01

    We propose an automated method for preoperative trajectory planning of deep brain stimulation image-guided neurosurgery. Our framework integrates multi-modal MRI analysis (T1w, SWI, TOF-MRA) to determine an optimal trajectory to DBS targets (subthalamic nuclei and globus pallidus interna) while avoiding critical brain structures for prevention of hemorrhages, loss of function and other complications. Results show that our method is well suited to aggregate many surgical constraints and allows the analysis of thousands of trajectories in less than 1/10th of the time for manual planning. Finally, a qualitative evaluation of computed trajectories resulted in the identification of potential new constraints, which are not addressed in the current literature, to better mimic the decision-making of the neurosurgeon during DBS planning.

  4. Dr. Lenke Horvath (1917-1991): Creator of Pediatric Neurosurgery in Romania.

    PubMed

    Mohan, Dumitru; Moisa, Horatiu Alexandru; Nica, Dan Aurel; Ciurea, Alexandru Vlad

    2016-04-01

    The development of neurosurgery as an independent specialty took place with great difficulty in Romania. In this respect, the most revered personalities are those of Professor Alexandru Moruzzi (1900-1957) (in Iasi) and Professor Dimitrie Bagdasar (1893-1946) (in Bucharest), who are the fathers of modern neurosurgery in Romania. Professor Bagdasar was schooled in Professor Harvey Cushing's clinic in Boston and is credited with creating the first completely independent neurosurgical unit in Romania. His legacy was carried on with honor by Professor Constantin Arseni (1912-1994), who, in 1975, tasked Dr. Lenke Horvath (1917-1991) with creating the first autonomous pediatric neurosurgery unit in Bucharest. This article is a small tribute to the founder of pediatric neurosurgery in Romania and one of the female pioneer neurosurgeons, who, by personal example of dedication and hard work, radically changed medical thinking and neurosurgery in Romania.

  5. Impairment of cardiac function and energetics in experimental renal failure.

    PubMed Central

    Raine, A E; Seymour, A M; Roberts, A F; Radda, G K; Ledingham, J G

    1993-01-01

    Cardiac function and energetics in experimental renal failure in the rat (5/6 nephrectomy) have been investigated by means of an isolated perfused working heart preparation and an isometric Langendorff preparation using 31P nuclear magnetic resonance (31P NMR). 4 wk after nephrectomy cardiac output of isolated hearts perfused with Krebs-Henseleit buffer was significantly lower (P < 0.0001) at all levels of preload and afterload in the renal failure groups than in the pair-fed sham operated control group. In control hearts, cardiac output increased with increases in perfusate calcium from 0.73 to 5.61 mmol/liter whereas uremic hearts failed in high calcium perfusate. Collection of 31P NMR spectra from hearts of renal failure and control animals during 30 min normoxic Langendorff perfusion showed that basal phosphocreatine was reduced by 32% to 4.7 mumol/g wet wt (P < 0.01) and the phosphocreatine to ATP ratio was reduced by 32% (P < 0.01) in uremic hearts. During low flow ischemia, there was a substantial decrease in phosphocreatine in the uremic hearts and an accompanying marked increase in release of inosine into the coronary effluent (14.9 vs 6.1 microM, P < 0.01). We conclude that cardiac function is impaired in experimental renal failure, in association with abnormal cardiac energetics and increased susceptibility to ischemic damage. Disordered myocardial calcium utilization may contribute to these derangements. PMID:8254048

  6. Neurosurgery Education and Development program to treat hydrocephalus and to develop neurosurgery in Africa using mobile neuroendoscopic training.

    PubMed

    Piquer, José; Qureshi, Mubashir Mahmood; Young, Paul H; Dempsey, Robert J

    2015-06-01

    OBJECT A shortage of neurosurgeons and a lack of knowledge of neuroendoscopic management of hydrocephalus limits modern care in sub-Saharan Africa. Hence, a mobile teaching project for endoscopic third ventriculostomy (ETV) procedures and a subsequent program to develop neurosurgery as a permanent specialty in Kenya and Zanzibar were created and sponsored by the Neurosurgery Education and Development (NED) Foundation and the Foundation for International Education in Neurological Surgery. The objective of this work was to evaluate the results of surgical training and medical care in both projects from 2006 to 2013. METHODS Two portable neuroendoscopy systems were purchased and a total of 38 ETV workshops were organized in 21 hospitals in 7 different countries. Additionally, 49 medical expeditions were dispatched to the Coast General Hospital in Mombasa, Kenya, and to the Mnazi Moja Hospital in Zanzibar. RESULTS From the first project, a total of 376 infants with hydrocephalus received surgery. Six-month follow-up was achieved in 22%. In those who received follow-up, ETV efficacy was 51%. The best success rates were achieved with patients 1 year of age or older with aqueductal stenosis (73%). The main causes of hydrocephalus were infection (56%) and spina bifida (23%). The mobile education program interacted with 72 local surgeons and 122 nurses who were trained in ETV procedures. The second project involved 49 volunteer neurosurgeons who performed a total of 360 nonhydrocephalus neurosurgical operations since 2009. Furthermore, an agreement with the local government was signed to create the Mnazi Mmoja NED Institute in Zanzibar. CONCLUSIONS Mobile endoscopic treatment of hydrocephalus in East Africa results in reasonable success rates and has also led to major developments in medicine, particularly in the development of neurosurgery specialty care sites.

  7. Experimental hydrodynamics of fish locomotion: functional insights from wake visualization.

    PubMed

    Drucker, Eliot G; Lauder, George V

    2002-04-01

    Despite enormous progress during the last twenty years in understanding the mechanistic basis of aquatic animal propulsion-a task involving the construction of a substantial data base on patterns of fin and body kinematics and locomotor muscle function-there remains a key area in which biologists have little information: the relationship between propulsor activity and water movement in the wake. How is internal muscular force translated into external force exerted on the water? What is the pattern of fluid force production by different fish fins (e.g., pectoral, caudal, dorsal) and how does swimming force vary with speed and among species? These types of questions have received considerable attention in analyses of terrestrial locomotion where force output by limbs can be measured directly with force plates. But how can forces exerted by animals moving through fluid be measured? The advent of digital particle image velocimetry (DPIV) has provided an experimental hydrodynamic approach for quantifying the locomotor forces of freely moving animals in fluids, and has resulted in significant new insights into the mechanisms of fish propulsion. In this paper we present ten "lessons learned" from the application of DPIV to problems of fish locomotion over the last five years. (1) Three-dimensional DPIV analysis is critical for reconstructing wake geometry. (2) DPIV analysis reveals the orientation of locomotor reaction forces. (3) DPIV analysis allows calculation of the magnitude of locomotor forces. (4) Swimming speed can have a major impact on wake structure. (5) DPIV can reveal interspecific differences in vortex wake morphology. (6) DPIV analysis can provide new insights into the limits to locomotor performance. (7) DPIV demonstrates the functional versatility of fish fins. (8) DPIV reveals hydrodynamic force partitioning among fins. (9) DPIV shows that wake interaction among fins may enhance thrust production. (10) Experimental hydrodynamic analysis can provide

  8. [Robotics in neurosurgery: current status and future prospects].

    PubMed

    Benabid, A L; Hoffmann, D; Ashraf, A; Koudsie, A; Esteve, F; Le Bas, J F

    1998-02-01

    Neurosurgery is in essence a field of application development for robots, based on multimodal image guidance. Specific motorized tools have already been developed and routinely applied in stereotaxy to position a probe holder or in conventional neurosurgery to hold a microscope oriented towards a given target. The potentialities of these approaches have triggered industrial developments which are now commercially available. These systems use databases, primarily coming from multimodal numerical images from X-ray radiology to magnetic resonance imaging. These spatially encoded data are transferred through digital networks to workstations where images can be processed and surgical procedures are pre-planned, then transferred to the robotic systems to which they are connected. We have been using a stereotaxic robot since 1989 and a microscope robot since 1995 in various surgical routine procedures. The future of these applications rely mainly on the technical progress in informatics, about image recognition to adapt the pre-planning to the actual surgical situation, to correct brain shifts (for instance), about image fusion, integrated knowledge such as brain atlases, as well as virtual reality. The future developments, covering surgical procedure, research and teaching, are sure to be far beyond our wildest expectations.

  9. Virtual reality simulation in neurosurgery: technologies and evolution.

    PubMed

    Chan, Sonny; Conti, François; Salisbury, Kenneth; Blevins, Nikolas H

    2013-01-01

    Neurosurgeons are faced with the challenge of learning, planning, and performing increasingly complex surgical procedures in which there is little room for error. With improvements in computational power and advances in visual and haptic display technologies, virtual surgical environments can now offer potential benefits for surgical training, planning, and rehearsal in a safe, simulated setting. This article introduces the various classes of surgical simulators and their respective purposes through a brief survey of representative simulation systems in the context of neurosurgery. Many technical challenges currently limit the application of virtual surgical environments. Although we cannot yet expect a digital patient to be indistinguishable from reality, new developments in computational methods and related technology bring us closer every day. We recognize that the design and implementation of an immersive virtual reality surgical simulator require expert knowledge from many disciplines. This article highlights a selection of recent developments in research areas related to virtual reality simulation, including anatomic modeling, computer graphics and visualization, haptics, and physics simulation, and discusses their implication for the simulation of neurosurgery.

  10. Interrupted time-series analysis: studying trends in neurosurgery.

    PubMed

    Wong, Ricky H; Smieliauskas, Fabrice; Pan, I-Wen; Lam, Sandi K

    2015-12-01

    OBJECT Neurosurgery studies traditionally have evaluated the effects of interventions on health care outcomes by studying overall changes in measured outcomes over time. Yet, this type of linear analysis is limited due to lack of consideration of the trend's effects both pre- and postintervention and the potential for confounding influences. The aim of this study was to illustrate interrupted time-series analysis (ITSA) as applied to an example in the neurosurgical literature and highlight ITSA's potential for future applications. METHODS The methods used in previous neurosurgical studies were analyzed and then compared with the methodology of ITSA. RESULTS The ITSA method was identified in the neurosurgical literature as an important technique for isolating the effect of an intervention (such as a policy change or a quality and safety initiative) on a health outcome independent of other factors driving trends in the outcome. The authors determined that ITSA allows for analysis of the intervention's immediate impact on outcome level and on subsequent trends and enables a more careful measure of the causal effects of interventions on health care outcomes. CONCLUSIONS ITSA represents a significant improvement over traditional observational study designs in quantifying the impact of an intervention. ITSA is a useful statistical procedure to understand, consider, and implement as the field of neurosurgery evolves in sophistication in big-data analytics, economics, and health services research.

  11. Inosine improves functional recovery after experimental traumatic brain injury.

    PubMed

    Dachir, Shlomit; Shabashov, Dalia; Trembovler, Victoria; Alexandrovich, Alexander G; Benowitz, Larry I; Shohami, Esther

    2014-03-25

    Despite years of research, no effective therapy is yet available for the treatment of traumatic brain injury (TBI). The most prevalent and debilitating features in survivors of TBI are cognitive deficits and motor dysfunction. A potential therapeutic method for improving the function of patients following TBI would be to restore, at least in part, plasticity to the CNS in a controlled way that would allow for the formation of compensatory circuits. Inosine, a naturally occurring purine nucleoside, has been shown to promote axon collateral growth in the corticospinal tract (CST) following stroke and focal TBI. In the present study, we investigated the effects of inosine on motor and cognitive deficits, CST sprouting, and expression of synaptic proteins in an experimental model of closed head injury (CHI). Treatment with inosine (100 mg/kg i.p. at 1, 24 and 48 h following CHI) improved outcome after TBI, significantly decreasing the neurological severity score (NSS, p<0.04 vs. saline), an aggregate measure of performance on several tasks. It improved non-spatial cognitive performance (object recognition, p<0.016 vs. saline) but had little effect on sensorimotor coordination (rotarod) and spatial cognitive functions (Y-maze). Inosine did not affect CST sprouting in the lumbar spinal cord but did restore levels of the growth-associated protein GAP-43 in the hippocampus, though not in the cerebral cortex. Our results suggest that inosine may improve functional outcome after TBI.

  12. Crystal structure solution from experimentally determined atomic pair distribution functions

    SciTech Connect

    Juhas, P.; Granlund, L.; Gujarathi, S.R.; Duxbury, P.M.; Billinge, S.J.L.

    2010-05-25

    An extension of the Liga algorithm for structure solution from atomic pair distribution functions (PDFs), to handle periodic crystal structures with multiple elements in the unit cell, is described. The procedure is performed in three separate steps. First, pair distances are extracted from the experimental PDF. In the second step the Liga algorithm is used to find unit-cell sites consistent with these pair distances. Finally, the atom species are assigned over the cell sites by minimizing the overlap of their empirical atomic radii. The procedure has been demonstrated on synchrotron X-ray PDF data from 16 test samples. The structure solution was successful for 14 samples, including cases with enlarged supercells. The algorithm success rate and the reasons for the failed cases are discussed, together with enhancements that should improve its convergence and usability.

  13. Experimental investigations of the functional morphology of dragonfly wings

    NASA Astrophysics Data System (ADS)

    Rajabi, H.; Darvizeh, A.

    2013-08-01

    Nowadays, the importance of identifying the flight mechanisms of the dragonfly, as an inspiration for designing flapping wing vehicles, is well known. An experimental approach to understanding the complexities of insect wings as organs of flight could provide significant outcomes for design purposes. In this paper, a comprehensive investigation is carried out on the morphological and microstructural features of dragonfly wings. Scanning electron microscopy (SEM) and tensile testing are used to experimentally verify the functional roles of different parts of the wings. A number of SEM images of the elements of the wings, such as the nodus, leading edge, trailing edge, and vein sections, which play dominant roles in strengthening the whole structure, are presented. The results from the tensile tests indicate that the nodus might be the critical region of the wing that is subjected to high tensile stresses. Considering the patterns of the longitudinal corrugations of the wings obtained in this paper, it can be supposed that they increase the load-bearing capacity, giving the wings an ability to tolerate dynamic loading conditions. In addition, it is suggested that the longitudinal veins, along with the leading and trailing edges, are structural mechanisms that further improve fatigue resistance by providing higher fracture toughness, preventing crack propagation, and allowing the wings to sustain a significant amount of damage without loss of strength.

  14. Multitrophic functional diversity predicts ecosystem functioning in experimental assemblages of estuarine consumers.

    PubMed

    Lefcheck, Jonathan S; Duffy, J Emmett

    2015-11-01

    The use of functional traits to explain how biodiversity affects ecosystem functioning has attracted intense interest, yet few studies have a priori altered functional diversity, especially in multitrophic communities. Here, we manipulated multivariate functional diversity of estuarine grazers and predators within multiple levels of species richness to test how species richness and functional diversity predicted ecosystem functioning in a multitrophic food web. Community functional diversity was a better predictor than species richness for the majority of ecosystem properties, based on generalized linear mixed-effects models. Combining inferences from eight traits into a single multivariate index increased prediction accuracy of these models relative to any individual trait. Structural equation modeling revealed that functional diversity of both grazers and predators was important in driving final biomass within trophic levels, with stronger effects observed for predators. We also show that different species drove different ecosystem responses, with evidence for both sampling effects and complementarity. Our study extends experimental investigations of functional trait diversity to a multilevel food web, and demonstrates that functional diversity can be more accurate and effective than species richness in predicting community biomass in a food web context.

  15. Experimental nonalcoholic steatohepatitis compromises ureagenesis, an essential hepatic metabolic function.

    PubMed

    Thomsen, Karen Louise; Grønbæk, Henning; Glavind, Emilie; Hebbard, Lionel; Jessen, Niels; Clouston, Andrew; George, Jacob; Vilstrup, Hendrik

    2014-08-01

    Nonalcoholic steatohepatitis (NASH) is increasing in prevalence, yet its consequences for liver function are unknown. We studied ureagenesis, an essential metabolic liver function of importance for whole body nitrogen homeostasis, in a rodent model of diet-induced NASH. Rats were fed a high-fat, high-cholesterol diet for 4 and 16 wk, resulting in early and advanced experimental NASH, respectively. We examined the urea cycle enzyme mRNAs in liver tissue, the hepatocyte urea cycle enzyme proteins, and the in vivo capacity of urea-nitrogen synthesis (CUNS). Early NASH decreased all of the urea cycle mRNAs to an average of 60% and the ornithine transcarbamylase protein to 10%, whereas the CUNS remained unchanged. Advanced NASH further decreased the carbamoyl phosphate synthetase protein to 63% and, in addition, decreased the CUNS by 20% [from 5.65 ± 0.23 to 4.58 ± 0.30 μmol × (min × 100 g)(-1); P = 0.01]. Early NASH compromised the genes and enzyme proteins involved in ureagenesis, whereas advanced NASH resulted in a functional reduction in the capacity for ureagenesis. The pattern of urea cycle perturbations suggests a prevailing mitochondrial impairment by NASH. The decrease in CUNS has consequences for the ability of the body to adjust to changes in the requirements for nitrogen homeostasis e.g., at stressful events. NASH, thus, in terms of metabolic consequences, is not an innocuous lesion, and the manifestations of the damage seem to be a continuum with increasing disease severity.

  16. Network inference from functional experimental data (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Desrosiers, Patrick; Labrecque, Simon; Tremblay, Maxime; Bélanger, Mathieu; De Dorlodot, Bertrand; Côté, Daniel C.

    2016-03-01

    Functional connectivity maps of neuronal networks are critical tools to understand how neurons form circuits, how information is encoded and processed by neurons, how memory is shaped, and how these basic processes are altered under pathological conditions. Current light microscopy allows to observe calcium or electrical activity of thousands of neurons simultaneously, yet assessing comprehensive connectivity maps directly from such data remains a non-trivial analytical task. There exist simple statistical methods, such as cross-correlation and Granger causality, but they only detect linear interactions between neurons. Other more involved inference methods inspired by information theory, such as mutual information and transfer entropy, identify more accurately connections between neurons but also require more computational resources. We carried out a comparative study of common connectivity inference methods. The relative accuracy and computational cost of each method was determined via simulated fluorescence traces generated with realistic computational models of interacting neurons in networks of different topologies (clustered or non-clustered) and sizes (10-1000 neurons). To bridge the computational and experimental works, we observed the intracellular calcium activity of live hippocampal neuronal cultures infected with the fluorescent calcium marker GCaMP6f. The spontaneous activity of the networks, consisting of 50-100 neurons per field of view, was recorded from 20 to 50 Hz on a microscope controlled by a homemade software. We implemented all connectivity inference methods in the software, which rapidly loads calcium fluorescence movies, segments the images, extracts the fluorescence traces, and assesses the functional connections (with strengths and directions) between each pair of neurons. We used this software to assess, in real time, the functional connectivity from real calcium imaging data in basal conditions, under plasticity protocols, and epileptic

  17. The development of neurosurgery at the University of Utah, 1955-2009.

    PubMed

    House, Paul A; Heilbrun, M Peter; Apfelbaum, Ronald I; Kraus, Kristin L; Couldwell, William T

    2010-09-01

    Located in the geographic Intermountain West, the Department of Neurosurgery at the University of Utah has undergone remarkable growth and transformation since the appointment of the first full-time clinical faculty member in 1955. The Department has provided broad neurosurgical services to an expanding community while fulfilling its academic mission of pushing the frontiers within neurosurgical subspecialties. The history of neurosurgery in the Salt Lake Valley and the achievements of the Department of Neurosurgery, including the seminal development of early cranial stereotactic devices, are reviewed in this article.

  18. Neurosurgery in Würzburg until World War II.

    PubMed

    Arnold, H; Collmann, H

    2012-01-01

    The institution of German neurosurgery as an autonomous surgical specialty, starting in Würzburg in 1934, is closely linked to the names of Fritz König and Wilhelm Tönnis. They were acting at a time when the global economic crisis and a consolidating Nazi dictatorship caused a cascade of alarming changes in political and social life. On the one hand it is fascinating to see how the restless work and energy of Tönnis managed to build up the first independent neurosurgical unit in Germany and to tighten efficient international connections all over the world within a few years. On the other hand-from a present-day perspective-it is difficult to understand how his strive towards a specialist's success, in contrast to that of Otfrid Foerster, was barely affected by the threatening political development, until the Second World War stopped his plans and ideas for many years.

  19. [Intraoperative monitoring of oxygen tissue pressure: Applications in vascular neurosurgery].

    PubMed

    Arikan, Fuat; Vilalta, Jordi; Torne, Ramon; Chocron, Ivette; Rodriguez-Tesouro, Ana; Sahuquillo, Juan

    2014-01-01

    Ischemic lesions related to surgical procedures are a major cause of postoperative morbidity in patients with cerebral vascular disease. There are different systems of neuromonitoring to detect intraoperative ischemic events, including intraoperative monitoring of oxygen tissue pressure (PtiO2). The aim of this article was to describe, through the discussion of 4 cases, the usefulness of intraoperative PtiO2 monitoring during vascular neurosurgery. In presenting these cases, we demonstrate that monitoring PtiO2 is a reliable way to detect early ischemic events during surgical procedures. Continuous monitoring of PtiO2 in an area at risk allows the surgeon to resolve the cause of the ischemic event before it evolves to an established cerebral infarction.

  20. The incidentaloma of the pituitary gland: Is neurosurgery required

    SciTech Connect

    Reincke, M.; Allolio, B.; Saeger, W.; Menzel, J.; Winkelmann, W. )

    1990-05-23

    The authors describe a series of 18 patients with an intrasellar mass incidentally discovered by computed tomography or magnetic resonance imaging. The average size of the mass was 13 mm, with a range from 5 to 25 mm. Initial ophthalmologic examination revealed bitemporal hemianopia in 2 patients. Results of routine endocrine testing showed partial hypopituitarism in 5 patients and growth hormone hypersecretion without signs and symptoms of acromegaly in 1 patient. Four patients underwent neurosurgery. Histologically, one chondroid chordoma and three pituitary adenomas were found. In the remaining 14 patients treated conservatively, repeated computed tomography and magnetic resonance imaging revealed no significant change in tumor size at the time of follow-up. The results suggest that the incidentaloma of the pituitary gland is a benign condition that does not necessarily require neurosurgical intervention.

  1. Simulation and augmented reality in endovascular neurosurgery: lessons from aviation.

    PubMed

    Mitha, Alim P; Almekhlafi, Mohammed A; Janjua, Major Jameel J; Albuquerque, Felipe C; McDougall, Cameron G

    2013-01-01

    Endovascular neurosurgery is a discipline strongly dependent on imaging. Therefore, technology that improves how much useful information we can garner from a single image has the potential to dramatically assist decision making during endovascular procedures. Furthermore, education in an image-enhanced environment, especially with the incorporation of simulation, can improve the safety of the procedures and give interventionalists and trainees the opportunity to study or perform simulated procedures before the intervention, much like what is practiced in the field of aviation. Here, we examine the use of simulators in the training of fighter pilots and discuss how similar benefits can compensate for current deficiencies in endovascular training. We describe the types of simulation used for endovascular procedures, including virtual reality, and discuss the relevant data on its utility in training. Finally, the benefit of augmented reality during endovascular procedures is discussed, along with future computerized image enhancement techniques.

  2. Balloons in endovascular neurosurgery: history and current applications.

    PubMed

    Alaraj, Ali; Wallace, Adam; Dashti, Reza; Patel, Prasad; Aletich, Victor

    2014-02-01

    The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.

  3. In vivo porcine training model for cranial neurosurgery.

    PubMed

    Regelsberger, Jan; Eicker, Sven; Siasios, Ioannis; Hänggi, Daniel; Kirsch, Matthias; Horn, Peter; Winkler, Peter; Signoretti, Stefano; Fountas, Kostas; Dufour, Henry; Barcia, Juan A; Sakowitz, Oliver; Westermaier, Thomas; Sabel, Michael; Heese, Oliver

    2015-01-01

    Supplemental education is desirable for neurosurgical training, and the use of human cadaver specimen and virtual reality models is routine. An in vivo porcine training model for cranial neurosurgery was introduced in 2005, and our recent experience with this unique model is outlined here. For the first time, porcine anatomy is illustrated with particular respect to neurosurgical procedures. The pros and cons of this model are described. The aim of the course was to set up a laboratory scenery imitating an almost realistic operating room in which anatomy of the brain and neurosurgical techniques in a mentored environment free from time constraints could be trained. Learning objectives of the course were to learn about the microsurgical techniques in cranial neurosurgery and the management of complications. Participants were asked to evaluate the quality and utility of the programme via standardized questionnaires by a grading scale from A (best) to E (worst). In total, 154 residents have been trained on the porcine model to date. None of the participants regarded his own residency programme as structured. The bleeding and complication management (97%), the realistic laboratory set-up (89%) and the working environment (94%) were favoured by the vast majority of trainees and confirmed our previous findings. After finishing the course, the participants graded that their skills in bone drilling, dissecting the brain and preserving cerebral vessels under microscopic magnification had improved to level A and B. In vivo hands-on courses, fully equipped with microsurgical instruments, offer an outstanding training opportunity in which bleeding management on a pulsating, vital brain represents a unique training approach. Our results have shown that education programmes still lack practical training facilities in which in vivo models may act as a complementary approach in surgical training.

  4. Platelet Function During Hypothermia in Experimental Mock Circulation.

    PubMed

    Van Poucke, Sven; Stevens, Kris; Kicken, Cécile; Simons, Antoine; Marcus, Abraham; Lancé, Marcus

    2016-03-01

    for platelet stimulation using COL, this trend continues during temperature drop from 37°C to 32°C. LTA values using AA and TRAP demonstrate a considerable decline in platelet function throughout the experiment that was most pronounced after 24 h of circulation at 32°C. LTA values using ADP and COL further decline after rewarming. MEA ADP, ASPI, and COL identify platelet dysfunction patterns analogous with LTA, between the start of the mock circulation and the start of cooling. Except for MEA TRAP, this trend continues during temperature drop from 37°C to 32°C. MEA ASPI and ADP demonstrate a considerable decline in platelet function throughout the experiment, which was most pronounced after 24 h of circulation at 32°C. For MEA COL and TRAP, further decline in platelet function is observed after rewarming. This study quantitatively assessed the effect of temperature changes on platelet function during experimental mock circulation demonstrating a considerable decline in platelet function during hypothermia without uniform recovery of platelet function observed after rewarming.

  5. Plumbagin suppresses dendritic cell functions and alleviates experimental autoimmune encephalomyelitis.

    PubMed

    Zhang, Kai; Ge, Zhenzhen; Da, Yurong; Wang, Dong; Liu, Ying; Xue, Zhenyi; Li, Yan; Li, Wen; Zhang, Lijuan; Wang, Huafeng; Zhang, Huan; Peng, Meiyu; Hao, Junwei; Yao, Zhi; Zhang, Rongxin

    2014-08-15

    Plumbagin (PL, 5-hydroxy-2-methyl-1,4-naphthoquinone) is a herbal compound derived from medicinal plants of the Droseraceae, Plumbaginaceae, Dioncophyllaceae, and Ancistrocladaceae families. Reports have shown that PL exerts immunomodulatory activity and may be a novel drug candidate for immune-related disease therapy. However, its effects on dendritic cells (DCs), the most potent antigen-presenting cells (APCs), remain unclear. In this study, we demonstrate that PL inhibits the differentiation, maturation, and function of human monocyte-derived DCs. PL can also restrict the expression of Th1- and Th17-polarizing cytokines in mDC. In addition, PL suppresses DCs both in vitro and in vivo, as demonstrated by its effects on the mouse DC line DC2.4 and mice with experimental autoimmune encephalomyelitis (EAE), respectively. Notably, PL ameliorated the clinical symptoms of EAE, including central nervous system (CNS) inflammation and demyelination. Our results demonstrate the immune suppressive and anti-inflammatory properties of PL via its effects on DCs and suggest that PL could be a potential treatment for DC-related autoimmune and inflammatory diseases.

  6. Critical Zone Experimental Design to Assess Soil Processes and Function

    NASA Astrophysics Data System (ADS)

    Banwart, Steve

    2010-05-01

    experimental design studies soil processes across the temporal evolution of the soil profile, from its formation on bare bedrock, through managed use as productive land to its degradation under longstanding pressures from intensive land use. To understand this conceptual life cycle of soil, we have selected 4 European field sites as Critical Zone Observatories. These are to provide data sets of soil parameters, processes and functions which will be incorporated into the mathematical models. The field sites are 1) the BigLink field station which is located in the chronosequence of the Damma Glacier forefield in alpine Switzerland and is established to study the initial stages of soil development on bedrock; 2) the Lysina Catchment in the Czech Republic which is representative of productive soils managed for intensive forestry, 3) the Fuchsenbigl Field Station in Austria which is an agricultural research site that is representative of productive soils managed as arable land and 4) the Koiliaris Catchment in Crete, Greece which represents degraded Mediterranean region soils, heavily impacted by centuries of intensive grazing and farming, under severe risk of desertification.

  7. Academic Productivity of US Neurosurgery Residents as Measured by H-Index: Program Ranking with Correlation to Faculty Productivity.

    PubMed

    Sarkiss, Christopher A; Riley, Kyle J; Hernandez, Christopher M; Oermann, Eric K; Ladner, Travis R; Bederson, Joshua B; Shrivastava, Raj K

    2017-03-29

    Engagement in research and academic productivity are crucial components in the training of a neurosurgeon. This process typically begins in residency training. In this study, we analyzed individual resident productivity as it correlated to publications across all Accreditation Council for Graduate Medical Education (ACGME)-accredited neurosurgery training programs in an attempt to identify how programs have developed and fostered a research culture and environment. We obtained a list of current neurosurgery residents in ACGME-accredited programs from the American Association of Neurological Surgeons database. An expanded PubMed and Scopus search was conducted for each resident through the present time. We tabulated all articles attributed to each resident. We then categorized the publications based on each neurosurgical subspecialty while in residency. A spreadsheet-based statistical analysis was performed. This formulated the average number of resident articles, h-indices, and most common subspecialty categories by training program. We analyzed 1352 current neurosurgery residents in 105 programs. There were a total of 10 645 publications, of which 3985 were resident first-author publications during the period of study. The most common subspecialties among all resident publications were vascular (24.9%), spine (16.9%), oncology (16.1%), pediatric (5.6%), functional (4.9%), and trauma (3.8%). The average resident published 2.9 first-author papers with average of 38.0 first-author publications by total residents at each program (range 0-241). The average h-index per resident is 2.47 ± 3.25. When comparing previously published faculty h-index program rankings against our resident h-index rankings, there is a strong correlation between the 2 datasets with a clear delineation between Top-20 productivity and that of other programs (average h-index 4.2 vs 1.7, respectively, P < .001). Increasing program size leads to a clear increase in academic productivity on both the

  8. Utilizing virtual and augmented reality for educational and clinical enhancements in neurosurgery.

    PubMed

    Pelargos, Panayiotis E; Nagasawa, Daniel T; Lagman, Carlito; Tenn, Stephen; Demos, Joanna V; Lee, Seung J; Bui, Timothy T; Barnette, Natalie E; Bhatt, Nikhilesh S; Ung, Nolan; Bari, Ausaf; Martin, Neil A; Yang, Isaac

    2017-01-01

    Neurosurgery has undergone a technological revolution over the past several decades, from trephination to image-guided navigation. Advancements in virtual reality (VR) and augmented reality (AR) represent some of the newest modalities being integrated into neurosurgical practice and resident education. In this review, we present a historical perspective of the development of VR and AR technologies, analyze its current uses, and discuss its emerging applications in the field of neurosurgery.

  9. The history of neurosurgery in Anatolia and Turkey: the Turkish Neurosurgical Society.

    PubMed

    Solaroglu, Ihsan; Acar, Feridun; Bavbek, Murad; Ture, Ugur; Beskonakli, Ethem

    2013-01-01

    Although the history of neurosurgery in Anatolia goes back ten thousand years, modern surgery began in Turkey in 1890. Neurosurgery in Turkey began in the first half of the 20th century. However, general surgeons began applying neurosurgical techniques back in the late 19th century. Most of these applications included procedures for craniocerebral traumas and infections. Dr. Cemil Topuzlu (1868-1958) is the founder of modern surgery in Turkey. Dr. Abdulkadir Cahit Tuner became the first neurosurgeon with a degree in Turkey in 1923. The first neurosurgery department was established in Istanbul in 1923, and the first training program began in the late 1940s. Currently there are almost 1200 neurosurgeons in Turkey and 75 training clinics at university hospitals and Training and Research Hospitals of the Ministry of Health provide neurosurgery training. The current state of neurosurgery in Turkey is parallel to that of the advanced Western countries. Apart from the application of neurosurgical procedures, there have been many scientific studies from Turkish neurosurgeons contributing to the total body of literature in neurosurgery.

  10. Preoperative anemia increases postoperative morbidity in elective cranial neurosurgery

    PubMed Central

    Bydon, Mohamad; Abt, Nicholas B.; Macki, Mohamed; Brem, Henry; Huang, Judy; Bydon, Ali; Tamargo, Rafael J.

    2014-01-01

    Background: Preoperative anemia may affect postoperative mortality and morbidity following elective cranial operations. Methods: The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database was used to identify elective cranial neurosurgical cases (2006-2012). Morbidity was defined as wound infection, systemic infection, cardiac, respiratory, renal, neurologic, and thromboembolic events, and unplanned returns to the operating room. For 30-day postoperative mortality and morbidity, adjusted odds ratios (ORs) were estimated with multivariable logistic regression. Results: Of 8015 patients who underwent elective cranial neurosurgery, 1710 patients (21.4%) were anemic. Anemic patients had an increased 30-day mortality of 4.1% versus 1.3% in non-anemic patients (P < 0.001) and an increased 30-day morbidity rate of 25.9% versus 14.14% in non-anemic patients (P < 0.001). The 30-day morbidity rates for all patients undergoing cranial procedures were stratified by diagnosis: 26.5% aneurysm, 24.7% sellar tumor, 19.7% extra-axial tumor, 14.8% intra-axial tumor, 14.4% arteriovenous malformation, and 5.6% pain. Following multivariable regression, the 30-day mortality in anemic patients was threefold higher than in non-anemic patients (4.1% vs 1.3%; OR = 2.77; 95% CI: 1.65-4.66). The odds of postoperative morbidity in anemic patients were significantly higher than in non-anemic patients (OR = 1.29; 95% CI: 1.03-1.61). There was a significant difference in postoperative morbidity event odds with a hematocrit level above (OR = 1.07; 95% CI: 0.78-1.48) and below (OR = 2.30; 95% CI: 1.55-3.42) 33% [hemoglobin (Hgb) 11 g/dl]. Conclusions: Preoperative anemia in elective cranial neurosurgery was independently associated with an increased risk of 30-day postoperative mortality and morbidity when compared to non-anemic patients. A hematocrit level below 33% (Hgb 11 g/dl) was associated with a significant increase in postoperative morbidity. PMID

  11. Construction of spline functions in spreadsheets to smooth experimental data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A previous manuscript detailed how spreadsheet software can be programmed to smooth experimental data via cubic splines. This addendum corrects a few errors in the previous manuscript and provides additional necessary programming steps. ...

  12. Thermal model to investigate the temperature in bone grinding for skull base neurosurgery.

    PubMed

    Zhang, Lihui; Tai, Bruce L; Wang, Guangjun; Zhang, Kuibang; Sullivan, Stephen; Shih, Albert J

    2013-10-01

    This study develops a thermal model utilizing the inverse heat transfer method (IHTM) to investigate the bone grinding temperature created by a spherical diamond tool used for skull base neurosurgery. Bone grinding is a critical procedure in the expanded endonasal approach to remove the cranial bone and access to the skull base tumor via nasal corridor. The heat is generated during grinding and could damage the nerve or coagulate the blood in the carotid artery adjacent to the bone. The finite element analysis is adopted to investigate the grinding-induced bone temperature rise. The heat source distribution is defined by the thermal model, and the temperature distribution is solved using the IHTM with experimental inputs. Grinding experiments were conducted on a bovine cortical bone with embedded thermocouples. Results show significant temperature rise in bone grinding. Using 50°C as the threshold, the thermal injury can propagate about 3mm in the traverse direction, and 3mm below the ground surface under the dry grinding condition. The presented methodology demonstrated the capability of being a thermal analysis tool for bone grinding study.

  13. Using Electronic Noses to Detect Tumors During Neurosurgery

    NASA Technical Reports Server (NTRS)

    Homer, Margie L.; Ryan, Margaret A.; Lara, Liana M.; Kateb, Babak; Chen, Mike

    2008-01-01

    It has been proposed to develop special-purpose electronic noses and algorithms for processing the digitized outputs of the electronic noses for determining whether tissue exposed during neurosurgery is cancerous. At present, visual inspection by a surgeon is the only available intraoperative technique for detecting cancerous tissue. Implementation of the proposal would help to satisfy a desire, expressed by some neurosurgeons, for an intraoperative technique for determining whether all of a brain tumor has been removed. The electronic-nose technique could complement multimodal imaging techniques, which have also been proposed as means of detecting cancerous tissue. There are also other potential applications of the electronic-nose technique in general diagnosis of abnormal tissue. In preliminary experiments performed to assess the viability of the proposal, the problem of distinguishing between different types of cultured cells was substituted for the problem of distinguishing between normal and abnormal specimens of the same type of tissue. The figure presents data from one experiment, illustrating differences between patterns that could be used to distinguish between two types of cultured cancer cells. Further development can be expected to include studies directed toward answering questions concerning not only the possibility of distinguishing among various types of normal and abnormal tissue but also distinguishing between tissues of interest and other odorous substances that may be present in medical settings.

  14. Clinical Characteristics of Patients with Trigeminal Neuralgia Referred to Neurosurgery

    PubMed Central

    Siqueira, Silvia RDT; Teixeira, Manoel J; Siqueira, José TT

    2009-01-01

    Objectives To investigate the clinical characteristics of patients with trigeminal neuralgia referred to surgery in a center of reference. Methods We evaluated the general characteristics of 395 patients with trigeminal neuralgia referred to neurosurgery as treatment. They corresponded to 2 samples of 1984 and 2004. The EDOF-HC protocol (Orofacial Pain Questionnaire) and the medical profile were used. Results In the first study (1984), with 290 patients, the higher prevalence was: women (57.3%), white (95.5%), with mean age of 62.5. The most affected trigeminal branches were the maxillary and/or mandibular branches (65.5%), and the right side was the most affected (57.6%). From the second study (2004), with 105 patients, 57.1% were women, 75.2% white, with a mean age of 60.8. The maxillary and/or mandibular branches (79.0%) and the right side (69.5%) were the most affected. Both samples had neurological abnormalities and systemic diseases (mainly cardiovascular). Conclusions General characteristics of these patients were similar to other samples of trigeminal neuralgia. Neurological findings were also present in patients with no previous surgical treatment for TN. Hypertension and cardiac diseases were also frequent and make the monitoring of the patients during crises necessary. PMID:19756195

  15. Experimental Economics for Teaching the Functioning of Electricity Markets

    ERIC Educational Resources Information Center

    Guevara-Cedeno, J. Y.; Palma-Behnke, R.; Uribe, R.

    2012-01-01

    In the field of electricity markets, the development of training tools for engineers has been extremely useful. A novel experimental economics approach based on a computational Web platform of an electricity market is proposed here for the practical teaching of electrical engineering students. The approach is designed to diminish the gap that…

  16. Animal Structures and Functions, Science (Experimental): 5314.13.

    ERIC Educational Resources Information Center

    Silver, Barbara A.

    This unit of instruction was designed to introduce the student to the relationship between structure and function in the animal kingdom, with emphasis given to: (1) the evolution of physiological systems in the major animal phyla, (2) the complementarity of structure and function, and (3) the concept of homeostasis. The booklet lists the relevant…

  17. Influence of experimental hypokinesia on gastric secretory function

    NASA Technical Reports Server (NTRS)

    Markova, O. O.; Vavryshchuk, V. I.; Rozvodovskyy, V. I.; Proshcheruk, V. A.

    1980-01-01

    The gastric secretory function of rats was studied in 4, 8, 16 and 30 day hypokinesia. Inhibition of both the gastric juice secretory and acid producing functions was found. The greatest inhibition was observed on day 8 of limited mobility. By days 16 and 30 of the experiment, a tendency of the gastric secretory activity to return to normal was observed, although it remained reduced.

  18. History of the Neurosurgery Department of Pontificia Universidad Catolica, Santiago, Chile.

    PubMed

    Sfeir, Felipe; Villanueva, Pablo; Tagle, Patricio

    2017-01-01

    Pontificia Universidad Católica de Chile's medical school was founded in 1929. An interest in neurosurgical development arose in the minds of the Dean, Dr. Cristobal Espíldora, and the Chief of Surgery, Dr. Rodolfo Rencoret, in 1946. They encouraged and supported Dr. J. Ricardo Olivares to specialize in Neurosurgery with Professor H. Olivecrona in Stockholm, Sweden. The first neurosurgical procedure in the Hospital Clínico de la Universidad Católica was performed in 1950. Since then, intensive efforts have been made to develop neurosurgery and its science. As a result, it is now a center capable of achieving high-quality standards in vascular, oncologic, and endoscopic neurosurgery; stereotactic and radiosurgery; complex spine surgery; pediatric neurosurgery; and epilepsy surgery. This article tells the story of a university hospital neurosurgery service in a country at the southern end of the world and how it became one of the most important neurosurgical centers in Chile and South America.

  19. Neurosurgery value and quality in the context of the Affordable Care Act: a policy perspective.

    PubMed

    Menger, Richard P; Guthikonda, Bharat; Storey, Christopher M; Nanda, Anil; McGirt, Matthew; Asher, Anthony

    2015-12-01

    Neurosurgeons provide direct individualized care to patients. However, the majority of regulations affecting the relative value of patient-related care are drafted by policy experts whose focus is typically system- and population-based. A central, prospectively gathered, national outcomes-related database serves as neurosurgery's best opportunity to bring patient-centered outcomes to the policy arena. In this study the authors analyze the impact of the Affordable Care Act (ACA) on the determination of quality and value in neurosurgery care through the scope, language, and terminology of policy experts. The methods by which the ACA came into law and the subsequent quality implications this legislation has for neurosurgery will be discussed. The necessity of neurosurgical patient-oriented clinical registries will be discussed in the context of imminent and dramatic reforms related to medical cost containment. In the policy debate moving forward, the strength of neurosurgery's argument will rest on data, unity, and proactiveness. The National Neurosurgery Quality and Outcomes Database (N(2)QOD) allows neurosurgeons to generate objective data on specialty-specific value and quality determinations; it allows neurosurgeons to bring the patient-physician interaction to the policy debate.

  20. Robotics in neurosurgery: state of the art and future technological challenges.

    PubMed

    Zamorano, L; Li, Q; Jain, S; Kaur, G

    2004-06-01

    The use of robotic technologies to assist surgeons was conceptually described almost thirty years ago but has only recently become feasible. In Neurosurgery, medical robots have been applied to neurosurgery for over 19 years. Nevertheless this field remains unknown to most neurosurgeons. The intrinsic characteristics of robots, such as high precision, repeatability and endurance make them ideal surgeon's assistants. Unfortunately, limitations in the current available systems make its use limited to very few centers in the world. During the last decade, important efforts have been made between academic and industry partnerships to develop robots suitable for use in the operating room environment. Although some applications have been successful in areas of laparoscopic surgery and orthopaedics, Neurosurgery has presented a major challenge due to the eloquence of the surrounding anatomy. This review focuses on the application of medical robotics in neurosurgery. The paper begins with an overview of the development of the medical robotics, followed by the current clinical applications in neurosurgery and an analysis of current limitations. We discuss robotic applications based in our own experience in the field. Next, we discuss the technological challenges and research areas to overcome those limitations, including some of our current research approaches for future progress in the field.

  1. Sensors management in robotic neurosurgery: the ROBOCAST project.

    PubMed

    Vaccarella, Alberto; Comparetti, Mirko Daniele; Enquobahrie, Andinet; Ferrigno, Giancarlo; De Momi, Elena

    2011-01-01

    Robot and computer-aided surgery platforms bring a variety of sensors into the operating room. These sensors generate information to be synchronized and merged for improving the accuracy and the safety of the surgical procedure for both patients and operators. In this paper, we present our work on the development of a sensor management architecture that is used is to gather and fuse data from localization systems, such as optical and electromagnetic trackers and ultrasound imaging devices. The architecture follows a modular client-server approach and was implemented within the EU-funded project ROBOCAST (FP7 ICT 215190). Furthermore it is based on very well-maintained open-source libraries such as OpenCV and Image-Guided Surgery Toolkit (IGSTK), which are supported from a worldwide community of developers and allow a significant reduction of software costs. We conducted experiments to evaluate the performance of the sensor manager module. We computed the response time needed for a client to receive tracking data or video images, and the time lag between synchronous acquisition with an optical tracker and ultrasound machine. Results showed a median delay of 1.9 ms for a client request of tracking data and about 40 ms for US images; these values are compatible with the data generation rate (20-30 Hz for tracking system and 25 fps for PAL video). Simultaneous acquisitions have been performed with an optical tracking system and US imaging device: data was aligned according to the timestamp associated with each sample and the delay was estimated with a cross-correlation study. A median value of 230 ms delay was calculated showing that realtime 3D reconstruction is not feasible (an offline temporal calibration is needed), although a slow exploration is possible. In conclusion, as far as asleep patient neurosurgery is concerned, the proposed setup is indeed useful for registration error correction because the brain shift occurs with a time constant of few tens of minutes.

  2. Consensus on guidelines for stereotactic neurosurgery for psychiatric disorders

    PubMed Central

    Nuttin, Bart; Wu, Hemmings; Mayberg, Helen; Hariz, Marwan; Gabriëls, Loes; Galert, Thorsten; Merkel, Reinhard; Kubu, Cynthia; Vilela-Filho, Osvaldo; Matthews, Keith; Taira, Takaomi; Lozano, Andres M; Schechtmann, Gastón; Doshi, Paresh; Broggi, Giovanni; Régis, Jean; Alkhani, Ahmed; Sun, Bomin; Eljamel, Sam; Schulder, Michael; Kaplitt, Michael; Eskandar, Emad; Rezai, Ali; Krauss, Joachim K; Hilven, Paulien; Schuurman, Rick; Ruiz, Pedro; Chang, Jin Woo; Cosyns, Paul; Lipsman, Nir; Voges, Juergen; Cosgrove, Rees; Li, Yongjie; Schlaepfer, Thomas

    2014-01-01

    Background For patients with psychiatric illnesses remaining refractory to ‘standard’ therapies, neurosurgical procedures may be considered. Guidelines for safe and ethical conduct of such procedures have previously and independently been proposed by various local and regional expert groups. Methods To expand on these earlier documents, representative members of continental and international psychiatric and neurosurgical societies, joined efforts to further elaborate and adopt a pragmatic worldwide set of guidelines. These are intended to address a broad range of neuropsychiatric disorders, brain targets and neurosurgical techniques, taking into account cultural and social heterogeneities of healthcare environments. Findings The proposed consensus document highlights that, while stereotactic ablative procedures such as cingulotomy and capsulotomy for depression and obsessive-compulsive disorder are considered ‘established’ in some countries, they still lack level I evidence. Further, it is noted that deep brain stimulation in any brain target hitherto tried, and for any psychiatric or behavioural disorder, still remains at an investigational stage. Researchers are encouraged to design randomised controlled trials, based on scientific and data-driven rationales for disease and brain target selection. Experienced multidisciplinary teams are a mandatory requirement for the safe and ethical conduct of any psychiatric neurosurgery, ensuring documented refractoriness of patients, proper consent procedures that respect patient's capacity and autonomy, multifaceted preoperative as well as postoperative long-term follow-up evaluation, and reporting of effects and side effects for all patients. Interpretation This consensus document on ethical and scientific conduct of psychiatric surgery worldwide is designed to enhance patient safety. PMID:24444853

  3. Robotic System for MRI-Guided Stereotactic Neurosurgery

    PubMed Central

    Li, Gang; Cole, Gregory A.; Shang, Weijian; Harrington, Kevin; Camilo, Alex; Pilitsis, Julie G.; Fischer, Gregory S.

    2015-01-01

    Stereotaxy is a neurosurgical technique that can take several hours to reach a specific target, typically utilizing a mechanical frame and guided by preoperative imaging. An error in any one of the numerous steps or deviations of the target anatomy from the preoperative plan such as brain shift (up to 20 mm), may affect the targeting accuracy and thus the treatment effectiveness. Moreover, because the procedure is typically performed through a small burr hole opening in the skull that prevents tissue visualization, the intervention is basically “blind” for the operator with limited means of intraoperative confirmation that may result in reduced accuracy and safety. The presented system is intended to address the clinical needs for enhanced efficiency, accuracy, and safety of image-guided stereotactic neurosurgery for Deep Brain Stimulation (DBS) lead placement. The work describes a magnetic resonance imaging (MRI)-guided, robotically actuated stereotactic neural intervention system for deep brain stimulation procedure, which offers the potential of reducing procedure duration while improving targeting accuracy and enhancing safety. This is achieved through simultaneous robotic manipulation of the instrument and interactively updated in situ MRI guidance that enables visualization of the anatomy and interventional instrument. During simultaneous actuation and imaging, the system has demonstrated less than 15% signal-to-noise ratio (SNR) variation and less than 0.20% geometric distortion artifact without affecting the imaging usability to visualize and guide the procedure. Optical tracking and MRI phantom experiments streamline the clinical workflow of the prototype system, corroborating targeting accuracy with 3-axis root mean square error 1.38 ± 0.45 mm in tip position and 2.03 ± 0.58° in insertion angle. PMID:25376035

  4. Simulation of brain tumor resection in image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoyao; Ji, Songbai; Fontaine, Kathryn; Hartov, Alex; Roberts, David; Paulsen, Keith

    2011-03-01

    Preoperative magnetic resonance images are typically used for neuronavigation in image-guided neurosurgery. However, intraoperative brain deformation (e.g., as a result of gravitation, loss of cerebrospinal fluid, retraction, resection, etc.) significantly degrades the accuracy in image guidance, and must be compensated for in order to maintain sufficient accuracy for navigation. Biomechanical finite element models are effective techniques that assimilate intraoperative data and compute whole-brain deformation from which to generate model-updated MR images (uMR) to improve accuracy in intraoperative guidance. To date, most studies have focused on early surgical stages (i.e., after craniotomy and durotomy), whereas simulation of more complex events at later surgical stages has remained to be a challenge using biomechanical models. We have developed a method to simulate partial or complete tumor resection that incorporates intraoperative volumetric ultrasound (US) and stereovision (SV), and the resulting whole-brain deformation was used to generate uMR. The 3D ultrasound and stereovision systems are complimentary to each other because they capture features deeper in the brain beneath the craniotomy and at the exposed cortical surface, respectively. In this paper, we illustrate the application of the proposed method to simulate brain tumor resection at three temporally distinct surgical stages throughout a clinical surgery case using sparse displacement data obtained from both the US and SV systems. We demonstrate that our technique is feasible to produce uMR that agrees well with intraoperative US and SV images after dural opening, after partial tumor resection, and after complete tumor resection. Currently, the computational cost to simulate tumor resection can be up to 30 min because of the need for re-meshing and the trial-and-error approach to refine the amount of tissue resection. However, this approach introduces minimal interruption to the surgical workflow

  5. Experimental Manipulation of the Microbial Functional Amyloid Called Curli

    PubMed Central

    Zhou, Yizhou; Smith, Daniel R.; Hufnagel, David A.; Chapman, Matthew R.

    2013-01-01

    Curli are proteinaceous fibrous structures produced on the surface of many gram-negative bacteria. As a major constituent of the extracellular matrix, curli mediate interactions between the bacteria and its environment, and as such, curli play a critical role in bio film formation. Curli fibers share biophysical properties with a growing number of remarkably stable and ordered protein aggregates called amyloid. Here we describe experimental methods to study the biogenesis and assembly of curli by exploiting their amyloid properties. We also present methods to analyze curli-mediated biofilm formation. These approaches are straightforward and can easily be adapted to study other bacterially produced amyloids. PMID:23299728

  6. Neurosurgery in Turkish poetry: three poets, two poems and two neurosurgeons.

    PubMed

    Kahilogullari, Gokmen

    2015-01-01

    Poems are essential in art and vital organs in literature. Similarly, surgery (and neurosurgery) is also regarded to be an art in medicine. From Hippocrates to nowadays, there is a debate on whether medicine -especially surgery- is a kind of an art or a field of science or a combination of both. This close relation becomes clearer during the practice of surgery, especially in neurosurgery. Herein, the relation between Turkish poetry and Turkish neurosurgery is being presented by researching the interesting and exciting stories about three poets (Can Yücel, Hasan Hüseyin Korkmazgil, Nazım Hikmet), their poems; and two Turkish neurosurgeons (Gazi Yaşargil, Yücel Kanpolat).

  7. Perioperative posterior reversible encephalopathy syndrome in 2 pediatric neurosurgery patients with brainstem ependymoma.

    PubMed

    Gephart, Melanie G Hayden; Taft, Bonnie P; Giese, Anne-Katrin; Guzman, Raphael; Edwards, Michael S B

    2011-03-01

    Posterior reversible encephalopathy syndrome (PRES) has been described in pediatric neurooncology patients, although it has not been documented perioperatively in pediatric neurosurgery patients not actively receiving chemotherapy. Recently at the authors' facility, 2 cases of PRES were diagnosed perioperatively in children with brainstem ependymoma. Both patients had presented with hypertension, altered mental status, and seizures and demonstrated MR imaging features consistent with PRES. The patients were treated with antiseizure and antihypertension medications, leading to improvement in both clinical symptoms and neuroimaging findings. These cases are the first to document PRES in perioperative pediatric neurosurgery patients not actively receiving chemotherapy. Both patients had ependymoma involving the brainstem, which may have led to intra- and perioperative hemodynamic instability (including hypertension) and predisposed them to this syndrome. An awareness of PRES in similar scenarios will aid in the prevention, diagnosis, and treatment of pediatric neurosurgery patients with this syndrome.

  8. High functional diversity stimulates diversification in experimental microbial communities.

    PubMed

    Jousset, Alexandre; Eisenhauer, Nico; Merker, Monika; Mouquet, Nicolas; Scheu, Stefan

    2016-06-01

    There is a growing awareness that biodiversity not only drives ecosystem services but also affects evolutionary dynamics. However, different theories predict contrasting outcomes on when do evolutionary processes occur within a context of competition. We tested whether functional diversity can explain diversification patterns. We tracked the survival and diversification of a focal bacterial species (Pseudomonas fluorescens) growing in bacterial communities of variable diversity and composition. We found that high functional diversity reduced the fitness of the focal species and, at the same time, fostered its diversification. This pattern was linked to resource competition: High diversity increased competition on a portion of the resources while leaving most underexploited. The evolved phenotypes of the focal species showed a better use of underexploited resources, albeit at a cost of lower overall growth rates. As a result, diversification alleviated the impact of competition on the fitness of the focal species. We conclude that biodiversity can stimulate evolutionary diversification, provided that sufficient alternative niches are available.

  9. Histamine H3 activation depresses cardiac function in experimental sepsis.

    PubMed

    Li, X; Eschun, G; Bose, D; Jacobs, H; Yang, J J; Light, R B; Mink, S N

    1998-11-01

    In the heart, histamine (H3) receptors may function as inhibitory presynaptic receptors that decrease adrenergic norepinephrine release in conditions of enhanced sympathetic neural activity. We hypothesized that H3-receptor blockade might improve cardiovascular function in sepsis. In a canine model of Escherichia coli sepsis, we found that H3-receptor blockade increased cardiac output (3.6 to 5.3 l/min, P < 0.05), systemic blood pressure (mean 76 to 96 mmHg, P < 0.05), and left ventricular contractility compared with pretreatment values. Plasma histamine concentrations increased modestly in the H3-blocker-sepsis group compared with values obtained in a nonsepsis-time-control group. In an in vitro preparation, histamine H3 activation could be identified under conditions of septic plasma. We conclude that activation of H3 receptors may contribute to cardiovascular collapse in sepsis.

  10. Statement of Ethics in Neurosurgery of the World Federation of Neurosurgical Societies.

    PubMed

    Umansky, Felix; Black, Peter L; DiRocco, Concenzio; Ferrer, Enrique; Goel, Atul; Malik, Ghaus M; Mathiesen, Tiit; Mendez, Ivar; Palmer, James D; Juanotena, Jorge Rodriguez; Fraifeld, Shifra; Rosenfeld, Jeffrey V

    2011-01-01

    This Statement of Ethics in Neurosurgery was developed by the Committee for Ethics and Medico-Legal Affairs of the World Federation of Neurosurgical Societies to help neurosurgeons resolve problems in the treatment of individual patients and meet obligations to the larger society. This document is intended as a framework rather than a set of rules. It cannot cover every situation and should be used with flexibility. However, it is our intent that the fundamental principles enunciated here should serve as a guide in the day-to-day practice of neurosurgery.

  11. [Characteristics of perioperative period in Xenon-based combined general anaesthesia in neurosurgery].

    PubMed

    Viatkin, A A; Petrosian, L G; Mizikov, V M; Vasil'ev, S A

    2013-01-01

    Neuroprotection could be the aim to use Xenon for general anesthesia. However the experience of Xenon anesthesia in neurosurgery is quite limited. The appraisal of Xenon based anesthesia was accomplished in 12 patients during various brain surgery. Xe in concentration 65% was used to maintenance of anesthesia, other medication was avoided. As a resuIt there were 8 cases of arterial hypertension and 2 cases of superficial hypnotic state. Excitation (n = 3), hyperdynamic reaction (n = 8), PONV (n = 8) were detected in early postoperative period. An analysis of this study suggests a conclusion that studied method of Xenon-based anesthesia is inexpedient for neurosurgery.

  12. Clinical Outcomes of Wulingsan Subtraction Decoction Treatment of Postoperative Brain Edema and Fever as a Complication of Glioma Neurosurgery

    PubMed Central

    Jin, Wei-rong; Zhang, Feng-e; Diao, Bao-zhong; Zhang, Yue-ying

    2016-01-01

    Objective. To evaluate the efficacy of Wulingsan subtraction (五苓散加减 WLSS) decoction in the treatment of postoperative brain edema and fever as a complication of glioma neurosurgery. Methods. This retrospective study was conducted at the Department of Neurosurgery of Liaocheng People's Hospital. Patients hospitalized between March 2011 and December 2014 were divided into three groups: Group A received WLSS oral liquid (50 mL), twice a day; Group B received an intravenous infusion of mannitol; and Group C received WLSS combined with mannitol (n = 30 patients per group). All patients were treated for 10 days continuously. Therapeutic efficacy was evaluated by measuring body temperature and indicators of renal function before and 3, 5, and 10 days after treatment. Results. Compared to the other two groups, significantly greater clinical efficacy was observed in the patients treated with mannitol (Group B; P < 0.05), although marked clinical efficacy was also observed over time in patients treated with WLSS (Group A). After 5 days, the quantifiable effects of the WLSS and mannitol combination group (Group C) were substantial (P < 0.05). The renal damage in Group B was more obvious after 5 days and 10 days. Conclusion. Compared with mannitol treatment alone, WLSS combined with mannitol induced a more rapid reduction in body temperature. Our findings suggest that patients should be started on mannitol for 3 days and then switched to WLSS to achieve obvious antipyretic effects and protect renal function. This method of treatment should be considered for clinical applications. PMID:27019661

  13. Experimental studies on islets isolation, purification and function in rats.

    PubMed

    Pang, Xinlu; Xue, Wujun; Feng, Xinshun; Tian, Xiaohui; Teng, Yan; Ding, Xiaoming; Pan, Xiaoming; Guo, Qi; He, Xiaoli

    2015-01-01

    To develop a simple and effective method of islet isolation and purification in rats. Collagenase P was injected into pancreatic duct followed by incubation in water bath to digest the pancreas and isolate islet, then discontinuous gravity gradient purification was used to purify the islet. The purified islets were identified by dithizone staining. The viability of islets was assessed by fluorescence staining of acridine orange (AO) and propidium iodide (PI). The function of purified islets was determined by glucose-stimulated insulin release test and transplantation of rat with streptozocin-induced diabetes. 738±193 islets were recovered after purification. The average purity was 77±13%, the viability of islets was more than 95%. When inspected by glucose stimulation, the secreted insulin concentration was 24.31±5.47 mIU/L when stimulated by low concentration glucose and 37.62±4.29 mIU/L by high concentration glucose. There was significant difference between the two phases (P<0.05). The blood sugar concentration recovered to normal level after two days in the animals with islet transplantation. In conclusion, islets can be procured with good function and shape by using the method of injecting collagenase into pancreatic duct followed by incubation in water bath and purification using discontinuous gravity gradient.

  14. [Leydig cell function in experimental cryptorchism and varicocele in rats].

    PubMed

    Hernández-Yánez, L; Marín-López, G; Vílchez-Martínez, J; Bishop, W

    1999-06-01

    Leydig cells were isolated from testes of normal, cryptorchid and induced- varicocele rats. These cells were counted and coincubated with and without human Chorionic Gonadotropin (hCG) during 3 hours; thereafter, steroids were measured in the incubation media. Cryptorchid animals showed the lowest number of Leydig cells, the highest Progesterone response to hCG, a slight increment of testosterone and a decrease of estradiol. On the contrary, both left and right testes from varicocele induced rats showed a higher cell number (per g of tissue), lower progesterone response, slightly higher response testosterone and lower testosterone response. These results demonstrate that these conditions of testicular hyperthermia do not affect the number and function of Leydig cells to the same degree. This may be due to differences in the testicular temperature reached with each procedure.

  15. Comparison of theoretical and experimental dielectric functions: Electron energy-loss spectroscopy and density-functional calculations on skutterudites

    NASA Astrophysics Data System (ADS)

    Prytz, Ø.; Løvvik, O. M.; Taftø, J.

    2006-12-01

    We explore the possibility of combining density functional theory (DFT) and electron energy loss spectroscopy (EELS) to determine the dielectric function of materials. As model systems we use the skutterudites CoP3 , CoAs3 , and CoSb3 which are prototypes for thermoelectric materials. We achieve qualitative agreement between the theoretically and experimentally obtained low energy-loss spectra and dielectric function. Some of the remaining discrepancies may be caused by the challenge of refining the experimental spectra before Kramers-Kronig analysis. However, contrary to what is the case for some crystals with less complicated electronic structure, the DFT calculated plasmon energies deviate significantly from the experimental values. The great accuracy with which the plasmon energy can be determined by EELS, suggests that this technique may provide valuable inputs in further efforts to improve DFT calculations. The use of EELS as the experimental technique may become particularly powerful in studies of small volumes of materials.

  16. Lymphatic vessel density and function in experimental bladder cancer

    PubMed Central

    Saban, Marcia R; Towner, Rheal; Smith, Nataliya; Abbott, Andrew; Neeman, Michal; Davis, Carole A; Simpson, Cindy; Maier, Julie; Mémet, Sylvie; Wu, Xue-Ru; Saban, Ricardo

    2007-01-01

    Background The lymphatics form a second circulatory system that drains the extracellular fluid and proteins from the tumor microenvironment, and provides an exclusive environment in which immune cells interact and respond to foreign antigen. Both cancer and inflammation are known to induce lymphangiogenesis. However, little is known about bladder lymphatic vessels and their involvement in cancer formation and progression. Methods A double transgenic mouse model was generated by crossing a bladder cancer-induced transgenic, in which SV40 large T antigen was under the control of uroplakin II promoter, with another transgenic mouse harboring a lacZ reporter gene under the control of an NF-κB-responsive promoter (κB-lacZ) exhibiting constitutive activity of β-galactosidase in lymphatic endothelial cells. In this new mouse model (SV40-lacZ), we examined the lymphatic vessel density (LVD) and function (LVF) during bladder cancer progression. LVD was performed in bladder whole mounts and cross-sections by fluorescent immunohistochemistry (IHC) using LYVE-1 antibody. LVF was assessed by real-time in vivo imaging techniques using a contrast agent (biotin-BSA-Gd-DTPA-Cy5.5; Gd-Cy5.5) suitable for both magnetic resonance imaging (MRI) and near infrared fluorescence (NIRF). In addition, IHC of Cy5.5 was used for time-course analysis of co-localization of Gd-Cy5.5 with LYVE-1-positive lymphatics and CD31-positive blood vessels. Results SV40-lacZ mice develop bladder cancer and permitted visualization of lymphatics. A significant increase in LVD was found concomitantly with bladder cancer progression. Double labeling of the bladder cross-sections with LYVE-1 and Ki-67 antibodies indicated cancer-induced lymphangiogenesis. MRI detected mouse bladder cancer, as early as 4 months, and permitted to follow tumor sizes during cancer progression. Using Gd-Cy5.5 as a contrast agent for MRI-guided lymphangiography, we determined a possible reduction of lymphatic flow within the

  17. Versatile utilization of real-time intraoperative contrast-enhanced ultrasound in cranial neurosurgery: technical note and retrospective case series

    PubMed Central

    Lekht, Ilya; Brauner, Noah; Bakhsheshian, Joshua; Chang, Ki-Eun; Gulati, Mittul; Shiroishi, Mark S.; Grant, Edward G.; Christian, Eisha; Zada, Gabriel

    2016-01-01

    OBJECTIVE Intraoperative contrast-enhanced ultrasound (iCEUS) offers dynamic imaging and provides functional data in real time. However, no standardized protocols or validated quantitative data exist to guide its routine use in neurosurgery. The authors aimed to provide further clinical data on the versatile application of iCEUS through a technical note and illustrative case series. METHODS Five patients undergoing craniotomies for suspected tumors were included. iCEUS was performed using a contrast agent composed of lipid shell microspheres enclosing perflutren (octafluoropropane) gas. Perfusion data were acquired through a time-intensity curve analysis protocol obtained using iCEUS prior to biopsy and/or resection of all lesions. RESULTS Three primary tumors (gemistocytic astrocytoma, glioblastoma multiforme, and meningioma), 1 metastatic lesion (melanoma), and 1 tumefactive demyelinating lesion (multiple sclerosis) were assessed using real-time iCEUS. No intraoperative complications occurred following multiple administrations of contrast agent in all cases. In all neoplastic cases, iCEUS replicated enhancement patterns observed on preoperative Gd-enhanced MRI, facilitated safe tumor de-bulking by differentiating neoplastic tissue from normal brain parenchyma, and helped identify arterial feeders and draining veins in and around the surgical cavity. Intraoperative CEUS was also useful in guiding a successful intraoperative needle biopsy of a cerebellar tumefactive demyelinating lesion obtained during real-time perfusion analysis. CONCLUSIONS Intraoperative CEUS has potential for safe, real-time, dynamic contrast-based imaging for routine use in neurooncological surgery and image-guided biopsy. Intraoperative CEUS eliminates the effect of anatomical distortions associated with standard neuronavigation and provides quantitative perfusion data in real time, which may hold major implications for intraoperative diagnosis, tissue differentiation, and quantification of

  18. Fedor Krause: the first systematic use of X-rays in neurosurgery.

    PubMed

    Elhadi, Ali M; Kalb, Samuel; Martirosyan, Nikolay L; Agrawal, Abhishek; Preul, Mark C

    2012-08-01

    Within a few months of Wilhelm Conrad Röntgen's discovery of x-rays in 1895, Fedor Krause acquired an x-ray apparatus and began to use it in his daily interactions with patients and for diagnosis. He was the first neurosurgeon to use x-rays methodically and systematically. In 1908 Krause published the first volume of text on neurosurgery, Chirurgie des Gehirns und Rückenmarks (Surgery of the Brain and Spinal Cord), which was translated into English in 1909. The second volume followed in 1911. This was the first published multivolume text totally devoted to neurosurgery. Although Krause excelled in and promoted neurosurgery, he believed that surgeons should excel at general surgery. Importantly, Krause was inclined to adopt technology that he believed could be helpful in surgery. His 1908 text was the first neurosurgical text to contain a specific chapter on x-rays ("Radiographie") that showed roentgenograms of neurosurgical procedures and pathology. After the revolutionary discovery of x-rays by Röntgen, many prominent neurosurgeons seemed pessimistic about the use of x-rays for anything more than trauma or fractures. Krause immediately seized on its use to guide and monitor ventricular drainage and especially for the diagnosis of tumors of the skull base. The x-ray images contained in Krause's "Radiographie" chapter provide a seminal view into the adoption of new technology and the development of neurosurgical technique and are part of neurosurgery's heritage.

  19. History of the Department of Neurosurgery at Thomas Jefferson University Hospital.

    PubMed

    Chalouhi, Nohra; Osterholm, Jewell; Jabbour, Pascal; Dumont, Aaron S; Gonzalez, L Fernando; Harrop, James; Sharan, Ashwini; Rosenwasser, Robert; Tjoumakaris, Stavropoula

    2013-10-01

    The neurosurgical tradition at Jefferson Medical College began in the 19th century with Samuel Gross. In his textbook entitled A System of Surgery, Gross revealed his knowledge of the disorders of the nervous system at a time when innovations were practically inexistent. Gross' work paved the way for William Williams Keen, "America's first brain surgeon." In 1887, Keen became the first surgeon in the nation to successfully remove a primary brain tumor. In 1893, Keen operated secretly on President Grover Cleveland for removal of an intraoral sarcoma and later served as a consultant to Franklin Roosevelt after he contracted poliomyelitis. The neurosurgery division was established in 1943 by J. Rudolph Jaeger. It was Philip Gordy who created a distinct Department of Neurosurgery in 1969. Jewell L. Osterholm became chairman of the Department of Neurosurgery in 1974. Since 2004, Robert Rosenwasser has served as chairman, and the Department of Neurosurgery at Jefferson has grown to include 26 faculty members. The residency has expanded to include 3 residents per academic year since 2007.

  20. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Self-retaining retractor for neurosurgery. 882.4800 Section 882.4800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4800...

  1. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Self-retaining retractor for neurosurgery. 882.4800 Section 882.4800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4800...

  2. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Self-retaining retractor for neurosurgery. 882.4800 Section 882.4800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4800...

  3. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Self-retaining retractor for neurosurgery. 882.4800 Section 882.4800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4800...

  4. 21 CFR 882.4800 - Self-retaining retractor for neurosurgery.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Self-retaining retractor for neurosurgery. 882.4800 Section 882.4800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4800...

  5. Roots of neuroanatomy, neurology, and neurosurgery as found in the Bible and Talmud.

    PubMed

    Tubbs, R Shane; Loukas, Marios; Shoja, Mohammadali M; Cohen-Gadol, Aaron A; Wellons, John C; Oakes, W Jerry

    2008-07-01

    Historical observations and interpretations regarding the treatment of components of the nervous system can be found in the writings of the Bible and Talmud. A review of topics germane to modern neuroanatomy, neurology, and neurosurgery from these early, rich writings is presented herein. These historic writings provide a glimpse into the early understanding, description, and treatment of pathologies of the nervous system.

  6. Biases in the experimental annotations of protein function and their effect on our understanding of protein function space.

    PubMed

    Schnoes, Alexandra M; Ream, David C; Thorman, Alexander W; Babbitt, Patricia C; Friedberg, Iddo

    2013-01-01

    The ongoing functional annotation of proteins relies upon the work of curators to capture experimental findings from scientific literature and apply them to protein sequence and structure data. However, with the increasing use of high-throughput experimental assays, a small number of experimental studies dominate the functional protein annotations collected in databases. Here, we investigate just how prevalent is the "few articles - many proteins" phenomenon. We examine the experimentally validated annotation of proteins provided by several groups in the GO Consortium, and show that the distribution of proteins per published study is exponential, with 0.14% of articles providing the source of annotations for 25% of the proteins in the UniProt-GOA compilation. Since each of the dominant articles describes the use of an assay that can find only one function or a small group of functions, this leads to substantial biases in what we know about the function of many proteins. Mass-spectrometry, microscopy and RNAi experiments dominate high throughput experiments. Consequently, the functional information derived from these experiments is mostly of the subcellular location of proteins, and of the participation of proteins in embryonic developmental pathways. For some organisms, the information provided by different studies overlap by a large amount. We also show that the information provided by high throughput experiments is less specific than those provided by low throughput experiments. Given the experimental techniques available, certain biases in protein function annotation due to high-throughput experiments are unavoidable. Knowing that these biases exist and understanding their characteristics and extent is important for database curators, developers of function annotation programs, and anyone who uses protein function annotation data to plan experiments.

  7. New technologies in neurosurgery: Effects on the conventional techniques and anaesthesiological considerations

    NASA Astrophysics Data System (ADS)

    Fasano, V. A.; Lombard, G. F.; Urciuoli, R.; Benech, F.; Ponzio, R. M.

    1985-09-01

    New technologies have been recently introduced into neurosurgery: laser sources, ultrasonic aspiration, intraoperative echotomography and intraoperative Doppler flowmeter. The aim of this work, showing the use of these instruments in different neurosurgical operations, is to discuss the effective improvements of the surgical techniques when comparing new and traditional technologies. The laser is able to concentrate high energies in restricted areas allowing a maximum selectivity. Having a superficial destructive effect with associated hemostasis, CO 2 and argon are suitable in dissection maneuvers. Nd:YAG produces a high thermal diffusion, consenting a deeper and extended tissue removal and a considerable reduction of intraoperative blood loss also in vascularized tumors. A promising field of application of the laser is the treatment of cerebral vascular malformations. In arterio-venous malformations the irradiation of the nidus with Nd:YAG produces a rapid obliteration of the pathologic vessels. This technique avoids the isolation of the feeding arteries and reduces the manipulation of the surrounding tissue. In small saccular aneurysms an argon laser is used to produce a shrinkage of the dilatation with consequent occlusion of the malformation. The ultrasonic aspirator is used in the tumoral surgery to obtain a more rapid demolition of the mass by fragmentation and suction. Intraoperative echotomography consents a sharp topographic localization of the lesion, particularly in deeper cerebral areas, providing data on the nature of solid tumors. The intraoperative Doppler flowmeter is useful for identification of the feeding arteries and the shunt of the small deep-seated arterio-venous malformations consenting a dynamic evaluation of the operation. General anaesthesia in neurosurgical procedures is favourably influenced by laser use. Conventional anaesthetic techniques, however, must be modified to avoid the harmful effect of the laser, depending on the movements

  8. Automatic deformable MR-ultrasound registration for image-guided neurosurgery.

    PubMed

    Rivaz, Hassan; Chen, Sean Jy-Shyang; Collins, D Louis

    2015-02-01

    In this work, we present a novel algorithm for registration of 3-D volumetric ultrasound (US) and MR using Robust PaTch-based cOrrelation Ratio (RaPTOR). RaPTOR computes local correlation ratio (CR) values on small patches and adds the CR values to form a global cost function. It is therefore invariant to large amounts of spatial intensity inhomogeneity. We also propose a novel outlier suppression technique based on the orientations of the RaPTOR gradients. Our deformation is modeled with free-form cubic B-splines. We analytically derive the derivatives of RaPTOR with respect to the transformation, i.e., the displacement of the B-spline nodes, and optimize RaPTOR using a stochastic gradient descent approach. RaPTOR is validated on MR and tracked US images of neurosurgery. Deformable registration of the US and MR images acquired, respectively, preoperation and postresection is of significant clinical significance, but challenging due to, among others, the large amount of missing correspondences between the two images. This work is also novel in that it performs automatic registration of this challenging dataset. To validate the results, we manually locate corresponding anatomical landmarks in the US and MR images of tumor resection in brain surgery. Compared to rigid registration based on the tracking system alone, RaPTOR reduces the mean initial mTRE over 13 patients from 5.9 to 2.9 mm, and the maximum initial TRE from 17.0 to 5.9 mm. Each volumetric registration using RaPTOR takes about 30 sec on a single CPU core. An important challenge in the field of medical image analysis is the shortage of publicly available dataset, which can both facilitate the advancement of new algorithms to clinical settings and provide a benchmark for comparison. To address this problem, we will make our manually located landmarks available online.

  9. Integration of patient specific modeling and advanced image processing techniques for image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Archip, Neculai; Fedorov, Andriy; Lloyd, Bryn; Chrisochoides, Nikos; Golby, Alexandra; Black, Peter M.; Warfield, Simon K.

    2006-03-01

    A major challenge in neurosurgery oncology is to achieve maximal tumor removal while avoiding postoperative neurological deficits. Therefore, estimation of the brain deformation during the image guided tumor resection process is necessary. While anatomic MRI is highly sensitive for intracranial pathology, its specificity is limited. Different pathologies may have a very similar appearance on anatomic MRI. Moreover, since fMRI and diffusion tensor imaging are not currently available during the surgery, non-rigid registration of preoperative MR with intra-operative MR is necessary. This article presents a translational research effort that aims to integrate a number of state-of-the-art technologies for MRI-guided neurosurgery at the Brigham and Women's Hospital (BWH). Our ultimate goal is to routinely provide the neurosurgeons with accurate information about brain deformation during the surgery. The current system is tested during the weekly neurosurgeries in the open magnet at the BWH. The preoperative data is processed, prior to the surgery, while both rigid and non-rigid registration algorithms are run in the vicinity of the operating room. The system is tested on 9 image datasets from 3 neurosurgery cases. A method based on edge detection is used to quantitatively validate the results. 95% Hausdorff distance between points of the edges is used to estimate the accuracy of the registration. Overall, the minimum error is 1.4 mm, the mean error 2.23 mm, and the maximum error 3.1 mm. The mean ratio between brain deformation estimation and rigid alignment is 2.07. It demonstrates that our results can be 2.07 times more precise then the current technology. The major contribution of the presented work is the rigid and non-rigid alignment of the pre-operative fMRI with intra-operative 0.5T MRI achieved during the neurosurgery.

  10. Experimental evidence for strong stabilizing forces at high functional diversity of aquatic microbial communities.

    PubMed

    Carrara, Francesco; Giometto, Andrea; Seymour, Mathew; Rinaldo, Andrea; Altermatt, Florian

    2015-05-01

    Unveiling the mechanisms that promote coexistence in biological communities is a fundamental problem in ecology. Stable coexistence of many species is commonly observed in natural communities. Most of these natural communities, however, are composed of species from multiple trophic and functional groups, while theory and experiments on coexistence have been focusing on functionally similar species. Here, we investigated how functional diversity affects the stability of species coexistence and productivity in multispecies communities by characterizing experimentally all pairwise species interactions in a pool of 11 species of eukaryotes (10 protists and one rotifer) belonging to three different functional groups. Species within the same functional group showed stronger competitive interactions compared to among-functional group interactions. This often led to competitive exclusion between species that had higher functional relatedness, but only at low levels of species richness. Communities with higher functional diversity resulted in increased species coexistence and community biomass production. Our experimental findings and the results of a stochastic model tailored to the experimental interaction matrix suggest the emergence of strong stabilizing forces when species from different functional groups interact in a homogeneous environment. By combining theoretical analysis with experiments we could also disentangle the relationship between species richness and functional diversity, showing that functional diversity per se is a crucial driver of productivity and stability in multispecies community.

  11. Effects of Physical Activity on Children's Executive Function: Contributions of Experimental Research on Aerobic Exercise

    ERIC Educational Resources Information Center

    Best, John R.

    2010-01-01

    Executive function refers to the cognitive processes necessary for goal-directed cognition and behavior, which develop across childhood and adolescence. Recent experimental research indicates that both acute and chronic aerobic exercise promote children's executive function. Furthermore, there is tentative evidence that not all forms of aerobic…

  12. Examining the Function of Problem Behavior in Fragile X Syndrome: Preliminary Experimental Analysis

    ERIC Educational Resources Information Center

    Langthorne, Paul; McGill, Peter; O'Reilly, Mark F.; Lang, Russell; Machalicek, Wendy; Chan, Jeffrey Michael; Rispoli, Mandy

    2011-01-01

    Fragile X syndrome is the most common inherited cause of intellectual and developmental disability. The influence of environmental variables on behaviors associated with the syndrome has received only scant attention. The current study explored the function served by problem behavior in fragile X syndrome by using experimental functional analysis…

  13. Linking functional group richness and ecosystem functions of dung beetles: an experimental quantification.

    PubMed

    Milotić, Tanja; Quidé, Stijn; Van Loo, Thomas; Hoffmann, Maurice

    2017-01-01

    Dung beetles form an insect group that fulfils important functions in terrestrial ecosystems throughout the world. These include nutrient cycling through dung removal, soil bioturbation, plant growth, secondary seed dispersal and parasite control. We conducted field experiments at two sites in the northern hemisphere temperate region in which dung removal and secondary seed dispersal were assessed. Dung beetles were classified in three functional groups, depending on their size and dung manipulation method: dwellers, large and small tunnelers. Other soil inhabiting fauna were included as a fourth functional group. Dung removal and seed dispersal by each individual functional group and combinations thereof were estimated in exclusion experiments using different dung types. Dwellers were the most diverse and abundant group, but tunnelers were dominant in terms of biomass. All dung beetle functional groups had a clear preference for fresh dung. The ecosystem services in dung removal and secondary seed dispersal provided by dung beetles were significant and differed between functional groups. Although in absolute numbers more dwellers were found, large tunnelers were disproportionally important for dung burial and seed removal. In the absence of dung beetles, other soil inhabiting fauna, such as earthworms, partly took over the dung decomposing role of dung beetles while most dung was processed when all native functional groups were present. Our results, therefore, emphasize the need to conserve functionally complete dung ecosystems to maintain full ecosystem functioning.

  14. Reproducibility and variability of the cost functions reconstructed from experimental recordings in multifinger prehension.

    PubMed

    Niu, Xun; Latash, Mark L; Zatsiorsky, Vladimir M

    2012-01-01

    The study examines whether the cost functions reconstructed from experimental recordings are reproducible over time. Participants repeated the trials on three days. By following Analytical Inverse Optimization procedures, the cost functions of finger forces were reconstructed for each day. The cost functions were found to be reproducible over time: application of a cost function C(i) to the data of Day j (i≠j) resulted in smaller deviations from the experimental observations than using other commonly used cost functions. Other findings are: (a) the 2nd order coefficients of the cost function showed negative linear relations with finger force magnitudes; (b) the finger forces were distributed on a 2-dimensional plane in the 4-dimensional finger force space for all subjects and all testing sessions; (c) the data agreed well with the principle of superposition, i.e. the action of object prehension can be decoupled into the control of rotational equilibrium and slipping prevention.

  15. A value-based, no-cost-to-patient health model in the developing world: Critical appraisal of a unique patient-centric neurosurgery unit

    PubMed Central

    Thakar, Sumit; Dadlani, Ravi; Sivaraju, Laxminadh; Aryan, Saritha; Mohan, Dilip; Sai Kiran, Narayanam Anantha; Rajarathnam, Ravikiran; Shyam, Maya; Sadanand, Venkatraman; Hegde, Alangar S.

    2015-01-01

    Background: It is well-accepted that the current healthcare scenario worldwide is due for a radical change, given that it is fraught with mounting costs and varying quality. Various modifications in health policies have been instituted toward this end. An alternative model, the low-cost, value-based health model, focuses on maximizing value for patients by moving away from a physician-centered, supply-driven system to a patient-centered system. Methods: The authors discuss the successful inception, functioning, sustainability, and replicability of a novel health model in neurosurgery built and sustained by inspired humanitarianism and that provides all treatment at no cost to the patients irrespective of their socioeconomic strata, color or creed. Results: The Sri Sathya Sai Institute of Higher Medical Sciences (SSSIHMS) at Whitefield, Bengaluru, India, a private charitable hospital established in 2001, functions on the ideals of providing free state-of-the-art healthcare to all in a compassionate and holistic manner. With modern equipment and respectable outcome benchmarks, its neurosurgery unit has operated on around 18,000 patients since its inception, and as such, has contributed INR 5310 million (USD 88.5 million) to society from an economic standpoint. Conclusions: The inception and sustainability of the SSSIHMS model are based on self-perpetuating philanthropy, a cost-conscious culture and the dissemination of human values. Replicated worldwide, at least in the developing nations, this unique healthcare model may well change the face of healthcare economics. PMID:26322241

  16. Mining high-throughput experimental data to link gene and function

    PubMed Central

    Blaby-Haas, Crysten E.; de Crécy-Lagard, Valérie

    2011-01-01

    Nearly 2200 genomes encoding some 6 million proteins have now been sequenced. Around 40% of these proteins are of unknown function even when function is loosely and minimally defined as “belonging to a superfamily”. In addition to in silico methods, the swelling stream of high-throughput experimental data can give valuable clues for linking these “unknowns” with precise biological roles. The goal is to develop integrative data-mining platforms that allow the scientific community at large to access and utilize this rich source of experimental knowledge. To this end, we review recent advances in generating whole-genome experimental datasets, where this data can be accessed, and how it can be used to drive prediction of gene function. PMID:21310501

  17. Problems with phenytoin administration in neurology/neurosurgery ITU patients receiving enteral feeding.

    PubMed

    Kitchen, D; Smith, D

    2001-06-01

    Our objective was to investigate the relationship between phenytoin bioavailability, enteral feeding and serum albumin levels in patients admitted to neurology/neurosurgery ITU, via case studies of three patients. The research was performed at the Walton centre for Neurology and Neurosurgery NHS Trust, Liverpool, England, and our subjects consisted of three cases admitted to ITU (1 status epilepticus, 1 post-trauma and 1 post-subarachnoid haemorrhage (SAH)). Phenytoin levels were assessed in relation to the type of feeding and serum albumin levels. We found evidence of a complex relationship between phenytoin levels, enteral feeding and serum albumin in patients in the neuro ITU setting. We conclude that, in this setting the patient's phenytoin needs to be closely monitored and treated aggressively to maintain therapeutic levels. They should also be followed up during rehabilitation to avoid toxicity.

  18. Neurosurgery in Rwanda during a United Nations peace-keeping mission.

    PubMed

    Rosenfeld, J V

    1997-05-01

    An analysis of the neurosurgical component of the medical support provided by a United Nations peace-keeping mission in Rwanda is presented. The Australian Defence Force contingent provided medical support to the United Nations and the civilian population. Eight hundred thirty-eight procedures were performed during 12 months. A wide range of surgery was encompassed, with neurosurgery accounting for 17 (2%) of the total operations: compound depressed fractured skull, 5; intracranial pressure monitor, 2; burr holes for acute head injury and chronic subdural hematoma, 2; skull osteomyelitis debridement, 1; rib-graft cranioplasty, 2; scalp rotation flap, 1; congenital myelomeningocele, 2; occipital meningocele, 1; craniofacial approach to Le Fort III fracture, 1. A broad range of neurosurgical procedures have been performed. The overall numbers of neurosurgical operations were small, but they were successfully performed by general surgeons. Familiarity with neurosurgery is necessary in predeployment training of military surgeons working in a remote location with limited resources.

  19. Neurosurgery in the realm of 10(-9), part 1: stardust and nanotechnology in neuroscience.

    PubMed

    Elder, James B; Liu, Charles Y; Apuzzo, Michael L J

    2008-01-01

    Nanotechnology as a science has evolved from notions and speculation to emerge as a prominent combination of science and engineering that stands to impact innumerable aspects of technology. Medicine in general and neurosurgery in particular will benefit greatly in terms of improved diagnostic and therapeutic capabilities. The recent explosion in nanotechnology products, including diverse applications such as beauty products and medical contrast agents, has been accompanied by an ever increasing volume of literature. Recent articles from our institution provided an historical and scientific background of nanotechnology, with a purposeful focus on nanomedicine. Future applications of nanotechnology to neuroscience and neurosurgery were briefly addressed. The present article is the first of two that will further this discussion by providing specific details of current nanotechnology applications and research related to neuroscience and clinical neurosurgery. This article also provides relevant perspective in scale, history, economics, and toxicology. Topics of specific importance to developments or advances of technologies used by neuroscientists and neurosurgeons are presented. In addition, advances in the field of microelectromechanical systems technology are discussed. Although larger than nanoscale, microelectromechanical systems technologies will play an important role in the future of medicine and neurosurgery. The second article will discuss current nanotechnologies that are being, or will be in the near future, incorporated into the armamentarium of the neurosurgeon. The goal of these articles is to keep the neuroscience community abreast of current developments in nanotechnology, nanomedicine, and, in particular, nanoneurosurgery, and to present possibilities for future applications of nanotechnology. As applications of nanotechnology permeate all forms of scientific and medical research, clinical applications will continue to emerge. Physicians of the

  20. Neurosurgery in Egypt: past, present, and future-from pyramids to radiosurgery.

    PubMed

    El Gindi, Sayed

    2002-09-01

    THE CONTEMPORARY DEVELOPMENT of neurosurgery in Egypt is described, with reference to the ancient past and recent American and European influences. This article traces the steps taken by several leading Egyptian pioneers. Egypt, one of the key countries in the Middle East, has led the development of the specialty in the region and has maintained close ties with the international body of neurological surgeons and surgical societies.

  1. The present and future of quality measures and public reporting in neurosurgery.

    PubMed

    Bekelis, Kimon; McGirt, Matthew J; Parker, Scott L; Holland, Christopher M; Davies, Jason; Devin, Clinton J; Atkins, Tyler; Knightly, Jack; Groman, Rachel; Zyung, Irene; Asher, Anthony L

    2015-12-01

    Quality measurement and public reporting are intended to facilitate targeted outcome improvement, practice-based learning, shared decision making, and effective resource utilization. However, regulatory implementation has created a complex network of reporting requirements for physicians and medical practices. These include Medicare's Physician Quality Reporting System, Electronic Health Records Meaningful Use, and Value-Based Payment Modifier programs. The common denominator of all these initiatives is that to avoid penalties, physicians must meet "generic" quality standards that, in the case of neurosurgery and many other specialties, are not pertinent to everyday clinical practice and hold specialists accountable for care decisions outside of their direct control. The Centers for Medicare and Medicaid Services has recently authorized alternative quality reporting mechanisms for the Physician Quality Reporting System, which allow registries to become subspecialty-reporting mechanisms under the Qualified Clinical Data Registry (QCDR) program. These programs further give subspecialties latitude to develop measures of health care quality that are relevant to the care provided. As such, these programs amplify the power of clinical registries by allowing more accurate assessment of practice patterns, patient experiences, and overall health care value. Neurosurgery has been at the forefront of these developments, leveraging the experience of the National Neurosurgery Quality and Outcomes Database to create one of the first specialty-specific QCDRs. Recent legislative reform has continued to change this landscape and has fueled optimism that registries (including QCDRs) and other specialty-driven quality measures will be a prominent feature of federal and private sector quality improvement initiatives. These physician- and patient-driven methods will allow neurosurgery to underscore the value of interventions, contribute to the development of sustainable health care

  2. Virtual reality training in neurosurgery: Review of current status and future applications

    PubMed Central

    Alaraj, Ali; Lemole, Michael G.; Finkle, Joshua H.; Yudkowsky, Rachel; Wallace, Adam; Luciano, Cristian; Banerjee, P. Pat; Rizzi, Silvio H.; Charbel, Fady T.

    2011-01-01

    Background: Over years, surgical training is changing and years of tradition are being challenged by legal and ethical concerns for patient safety, work hour restrictions, and the cost of operating room time. Surgical simulation and skill training offer an opportunity to teach and practice advanced techniques before attempting them on patients. Simulation training can be as straightforward as using real instruments and video equipment to manipulate simulated “tissue” in a box trainer. More advanced virtual reality (VR) simulators are now available and ready for widespread use. Early systems have demonstrated their effectiveness and discriminative ability. Newer systems enable the development of comprehensive curricula and full procedural simulations. Methods: A PubMed review of the literature was performed for the MESH words “Virtual reality, “Augmented Reality”, “Simulation”, “Training”, and “Neurosurgery”. Relevant articles were retrieved and reviewed. A review of the literature was performed for the history, current status of VR simulation in neurosurgery. Results: Surgical organizations are calling for methods to ensure the maintenance of skills, advance surgical training, and credential surgeons as technically competent. The number of published literature discussing the application of VR simulation in neurosurgery training has evolved over the last decade from data visualization, including stereoscopic evaluation to more complex augmented reality models. With the revolution of computational analysis abilities, fully immersive VR models are currently available in neurosurgery training. Ventriculostomy catheters insertion, endoscopic and endovascular simulations are used in neurosurgical residency training centers across the world. Recent studies have shown the coloration of proficiency with those simulators and levels of experience in the real world. Conclusion: Fully immersive technology is starting to be applied to the practice of

  3. Reconstruction of the unknown optimization cost functions from experimental recordings during static multi-finger prehension.

    PubMed

    Niu, Xun; Terekhov, Alexander V; Latash, Mark L; Zatsiorsky, Vladimir M

    2012-04-01

    The goal of the research is to reconstruct the unknown cost (objective) function(s) presumably used by the neural controller for sharing the total force among individual fingers in multifinger prehension. The cost function was determined from experimental data by applying the recently developed Analytical Inverse Optimization (ANIO) method (Terekhov et al. 2010). The core of the ANIO method is the Theorem of Uniqueness that specifies conditions for unique (with some restrictions) estimation of the objective functions. In the experiment, subjects (n = 8) grasped an instrumented handle and maintained it at rest in the air with various external torques, loads, and target grasping forces applied to the object. The experimental data recorded from 80 trials showed a tendency to lie on a 2-dimensional hyperplane in the 4-dimensional finger-force space. Because the constraints in each trial were different, such a propensity is a manifestation of a neural mechanism (not the task mechanics). In agreement with the Lagrange principle for the inverse optimization, the plane of experimental observations was close to the plane resulting from the direct optimization. The latter plane was determined using the ANIO method. The unknown cost function was reconstructed successfully for each performer, as well as for the group data. The cost functions were found to be quadratic with nonzero linear terms. The cost functions obtained with the ANIO method yielded more accurate results than other optimization methods. The ANIO method has an evident potential for addressing the problem of optimization in motor control.

  4. The National Neurosurgery Quality and Outcomes Database Qualified Clinical Data Registry: 2015 measure specifications and rationale.

    PubMed

    Parker, Scott L; McGirt, Matthew J; Bekelis, Kimon; Holland, Christopher M; Davies, Jason; Devin, Clinton J; Atkins, Tyler; Knightly, Jack; Groman, Rachel; Zyung, Irene; Asher, Anthony L

    2015-12-01

    Meaningful quality measurement and public reporting have the potential to facilitate targeted outcome improvement, practice-based learning, shared decision making, and effective resource utilization. Recent developments in national quality reporting programs, such as the Centers for Medicare & Medicaid Services Qualified Clinical Data Registry (QCDR) reporting option, have enhanced the ability of specialty groups to develop relevant quality measures of the care they deliver. QCDRs will complete the collection and submission of Physician Quality Reporting System (PQRS) quality measures data on behalf of individual eligible professionals. The National Neurosurgery Quality and Outcomes Database (N(2)QOD) offers 21 non-PQRS measures, initially focused on spine procedures, which are the first specialty-specific measures for neurosurgery. Securing QCDR status for N(2)QOD is a tremendously important accomplishment for our specialty. This program will ensure that data collected through our registries and used for PQRS is meaningful for neurosurgeons, related spine care practitioners, their patients, and other stakeholders. The 2015 N(2)QOD QCDR is further evidence of neurosurgery's commitment to substantively advancing the health care quality paradigm. The following manuscript outlines the measures now approved for use in the 2015 N(2)QOD QCDR. Measure specifications (measure type and descriptions, related measures, if any, as well as relevant National Quality Strategy domain[s]) along with rationale are provided for each measure.

  5. Laser neurosurgery: A systematic analysis of magnetic resonance-guided laser interstitial thermal therapies.

    PubMed

    Lagman, Carlito; Chung, Lawrance K; Pelargos, Panayiotis E; Ung, Nolan; Bui, Timothy T; Lee, Seung J; Voth, Brittany L; Yang, Isaac

    2017-02-01

    Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a novel minimally invasive modality that uses heat from laser probes to destroy tissue. Advances in probe design, cooling mechanisms, and real-time MR thermography have increased laser utilization in neurosurgery. The authors perform a systematic analysis of two commercially available MRgLITT systems used in neurosurgery: the Visualase® thermal therapy and NeuroBlate® Systems. Data extraction was performed in a blinded fashion. Twenty-two articles were included in the quantitative synthesis. A total of 223 patients were identified with the majority having undergone treatment with Visualase (n=154, 69%). Epilepsy was the most common indication for Visualase therapy (n=8 studies, 47%). Brain mass was the most common indication for NeuroBlate therapy (n=3 studies, 60%). There were no significant differences, except in age, wherein the NeuroBlate group was nearly twice as old as the Visualase group (p<0.001). Frame, total complications, and length-of-stay (LOS) were non-significant when adjusted for age and number of patients. Laser neurosurgery has evolved over recent decades. Clinical indications are currently being defined and will continue to emerge as laser technologies become more sophisticated. Head-to-head comparison of these systems was difficult given the variance in indications (and therefore patient population) and disparate literature.

  6. Experimental investigations of the scanning functions of galvanometer-based scanners with applications in OCT.

    PubMed

    Duma, Virgil-Florin; Lee, Kye-sung; Meemon, Panomsak; Rolland, Jannick P

    2011-10-10

    We analyze the three most common profiles of scanning functions for galvanometer-based scanners (GSs): the sawtooth, triangular and sinusoidal functions. They are determined experimentally with regard to the scan parameters of the input signal (i.e., frequency and amplitude). We study the differences of the output function of the GS measured as the positional error of the oscillatory mirror from the ideal function given by the input signal of the device. The limits in achieving the different types of scanning functions in terms of duty cycle and linearity are determined experimentally for the possible range of scan parameters. Of particular importance are the preservation of an imposed duty cycle and profile for the sawtooth function, the quantification of the linearity for the sinusoidal function, and the effective duty cycle for the triangular, as well as for the other functions. The range of scan amplitudes for which the stability of the oscillatory regime of the galvo mirror is stable for different frequencies is also highlighted. While the use of the device in certain scanning regimes is studied, certain rules of thumb are deduced to make the best out of the galvoscanner. Finally, the three types of scanning functions are tested with a Fourier domain optical coherence tomography (FD OCT) setup and the conclusions of the study are demonstrated in an imaging application by correlating the determined limits of the scanning regimes with the requirements of OCT.

  7. The Richard C. Schneider Lecture. New dimensions of neurosurgery in the realm of high technology: possibilities, practicalities, realities.

    PubMed

    Apuzzo, M L

    1996-04-01

    Fueled by a buoyant economy, popular attitudes and demands, and parallel progress in transferable technical and biological areas, neurosurgery has enjoyed a remarkable quarter of a century of progress. Developmental trends in the discipline have included the following: 1) a refinement of preoperative definition of the structural substrate, 2) miniaturization of operative corridors, 3) reduction of operative trauma, 4) increased effectiveness at the target site, and 5) incorporation of improved technical adjuvants and physical operative tools into treatment protocols. In particular, the computer has become a formidable ally in diagnostic and surgical events. Trends in technical development indicate that we are entering an exciting era of advanced surgery of the human cerebrum, which is heralded by the following: 1) current developments in areas of imaging, sensors, and visualization; 2) new devices for localization and navigation; 3) new capabilities for action at the target point; and 4) innovative concepts related to advanced operative venues. Imaging has provided structurally based surgical maps, which now are being given the new dimension of function in complex and integrated formats for preoperative planning and intraoperative tactical direction. Cerebral localization and navigation based on these advances promise to provide further refinement to the field of stereotactic neurosurgery, as linked systems are superseded by more flexible nonlinked methodologies in functionally defined volume-oriented navigational databases. Target point action now includes not only ablative capabilities through micro-operative methods and the use of stereotactically directed high-energy forms but also the emergence of restorative capabilities through applications of principles of genetic engineering in the areas of molecular and cellular neurosurgery. Complex, dedicated, and self-contained operative venues will be required to optimize the emergence and development of these

  8. IL-9 regulates intestinal barrier function in experimental T cell-mediated colitis

    PubMed Central

    Gerlach, Katharina; McKenzie, Andrew N; Neurath, Markus F; Weigmann, Benno

    2015-01-01

    As previous studies suggested that IL-9 may control intestinal barrier function, we tested the role of IL-9 in experimental T cell-mediated colitis induced by the hapten reagent 2,4,6-trinitrobenzenesulfonic acid (TNBS). The deficiency of IL-9 suppressed TNBS-induced colitis and led to lower numbers of PU.1 expressing T cells in the lamia propria, suggesting a regulatory role for Th9 cells in the experimental TNBS colitis model. Since IL-9 is known to functionally alter intestinal barrier function in colonic inflammation, we assessed the expression of tight junction molecules in intestinal epithelial cells of TNBS-inflamed mice. Therefore we made real-time PCR analyses for tight junction molecules in the inflamed colon from wild-type and IL-9 KO mice, immunofluorescent stainings and investigated the expression of junctional proteins directly in intestinal epithelial cells of TNBS-inflamed mice by Western blot studies. The results demonstrated that sealing proteins like occludin were up regulated in the colon of inflamed IL-9 KO mice. In contrast, the tight junction protein Claudin1 showed lower expression levels when IL-9 is absent. Surprisingly, the pore-forming molecule Claudin2 revealed equal expression in TNBS-treated wild-type and IL-9-deficient animals. These results illustrate the pleiotropic functions of IL-9 in changing intestinal permeability in experimental colitis. Thus, modulation of IL-9 function emerges as a new approach for regulating barrier function in intestinal inflammation. PMID:25838986

  9. Experimental demonstration of linear precompensation of a nonlinear transfer function due to second-harmonic generation.

    PubMed

    Vidal, Sébastien; Luce, Jacques; Penninckx, Denis

    2011-01-01

    We report on what we believe is the first experimental demonstration of the linear precompensation of a nonlinear transfer function due to frequency conversion. As a proof of principle, we show the effective precompensation with an interferometric filter of FM-to-AM conversion due to second-harmonic generation in a potassium titanyl phosphate crystal.

  10. Comparison between skin-mounted fiducials and bone-implanted fiducials for image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Rost, Jennifer; Harris, Steven S.; Stefansic, James D.; Sillay, Karl; Galloway, Robert L., Jr.

    2004-05-01

    Point-based registration for image-guided neurosurgery has become the industry standard. While the use of intrinsic points is appealing because of its retrospective nature, affixing extrinsic objects to the head prior to scanning has been demonstrated to provide much more accurate registrations. Points of reference between image space and physical space are called fiducials. The extrinsic objects which generate those points are fiducial markers. The markers can be broken down into two classifications: skin-mounted and bone-implanted. Each has distinct advantages and disadvantages. Skin-mounted fiducials require simply sticking them on the patient in locations suggested by the manufacturer, however, they can move with tractions placed on the skin, fall off and perhaps the most dangerous problem, they can be replaced by the patient. Bone implanted markers being rigidly affixed to the skull do not present such problems. However, a minor surgical intervention (analogous to dental work) must be performed to implant the markers prior to surgery. Therefore marker type and use has become a decision point for image-guided surgery. We have performed a series of experiments in an attempt to better quantify aspects of the two types of markers so that better informed decisions can be made. We have created a phantom composed of a full-size plastic skull [Wards Scientific Supply] with a 500 ml bag of saline placed in the brain cavity. The skull was then sealed. A skin mimicking material, DragonSkinTM [SmoothOn Company] was painted onto the surface and allowed to dry. Skin mounted fiducials [Medtronic-SNT] and bone-implanted markers [Z-Kat]were placed on the phantom. In addition, three additional bone-implanted markers were placed (two on the base of the skull and one in the eye socket for use as targets). The markers were imaged in CT and 4 MRI sequences (T1-weighted, T2 weighted, SPGR, and a functional series.) The markers were also located in physical space using an Optotrak

  11. Real-time correction scheme for calibration and implementation of microscope-based image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Sun, Hai; Farid, Hany; Hartov, Alex; Lunn, Karen E.; Roberts, David W.; Paulsen, Keith D.

    2002-05-01

    Microscope-based image-guided neurosurgery can be divided into three steps: calibration of the microscope optics; registration of the pre-operative images to the operating space; and tracking of the patient and microscope over time. Critical to this overall system is the temporal retention of accurate camera calibration. Classic calibration algorithms are routinely employed to find both intrinsic and extrinsic camera parameters. The accuracy of this calibration, however, is quickly compromised due to the complexity of the operating room, the long duration of a surgical procedure, and the inaccuracies in the tracking system. To compensate for the changing conditions, we have developed an adaptive procedure which responds to accruing registration error. The approach utilizes miniature fiducial markers implanted on the bony rim of the craniotomy site, which remain in the field of view of the operating microscope. A simple error function that enforces the registration of the known fiducial markers is used to update the extrinsic camera parameters. The error function is minimized using a gradient descent. This correction procedure reduces RMS registration errors for cortical features on the surface of the brain by an average of 72%, or 1.5 mm. These errors were reduced to less than 0.6 mm after each correction during the entire surgical procedure.

  12. Preliminary Results on the Experimental Investigation of the Structure Functions of Bound Nucleons

    SciTech Connect

    Bodek, Arie

    2016-08-01

    We present preliminary results on an experimental study of the nuclear modification of the longitudinal ($\\sigma_L$) and transverse ($\\sigma_T$) structure functions of nucleons bound in nuclear targets. The origin of these modifications (commonly referred as as the EMC effect) is not fully understood. Our measurements of R= $\\sigma_L / \\sigma_T$ for nuclei ($R_A$) and for deuterium ($R_D$) indicate that nuclear modifications of the structure functions of bound nucleons are different for the longitudinal and transverse structure functions, and that contrary to expectation from several theoretical models, $R_A< R_D$.

  13. Leveraging enzyme structure-function relationships for functional inference and experimental design: the structure-function linkage database.

    PubMed

    Pegg, Scott C-H; Brown, Shoshana D; Ojha, Sunil; Seffernick, Jennifer; Meng, Elaine C; Morris, John H; Chang, Patricia J; Huang, Conrad C; Ferrin, Thomas E; Babbitt, Patricia C

    2006-02-28

    The study of mechanistically diverse enzyme superfamilies-collections of enzymes that perform different overall reactions but share both a common fold and a distinct mechanistic step performed by key conserved residues-helps elucidate the structure-function relationships of enzymes. We have developed a resource, the structure-function linkage database (SFLD), to analyze these structure-function relationships. Unique to the SFLD is its hierarchical classification scheme based on linking the specific partial reactions (or other chemical capabilities) that are conserved at the superfamily, subgroup, and family levels with the conserved structural elements that mediate them. We present the results of analyses using the SFLD in correcting misannotations, guiding protein engineering experiments, and elucidating the function of recently solved enzyme structures from the structural genomics initiative. The SFLD is freely accessible at http://sfld.rbvi.ucsf.edu.

  14. Reproducibility and Variability of the Cost Functions Reconstructed from Experimental Recordings in Multi-Finger Prehension

    PubMed Central

    Niu, Xun; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2012-01-01

    The main goal of the study is to examine whether the cost (objective) functions reconstructed from experimental recordings in multi-finger prehension tasks are reproducible over time, i.e., whether the functions reflect stable preferences of the subjects and can be considered personal characteristics of motor coordination. Young, healthy participants grasped an instrumented handle with varied values of external torque, load and target grasping force and repeated the trials on three days: Day 1, Day 2, and Day 7. By following Analytical Inverse Optimization (ANIO) computation procedures, the cost functions for individual subjects were reconstructed from the experimental recordings (individual finger forces) for each day. The cost functions represented second-order polynomials of finger forces with non-zero linear terms. To check whether the obtained cost functions were reproducible over time a cross-validation was performed: a cost function obtained on Day i was applied to experimental data observed on Day j (i≠j). In spite of the observed day-to-day variability of the performance and the cost functions, the ANIO reconstructed cost functions were found to be reproducible over time: application of a cost function Ci to the data of Day j (i≠j) resulted in smaller deviations from the experimental observations than using other commonly used cost functions. Other findings are: (a) The 2nd order coefficients Ki of the cost function showed negative linear relations with finger force magnitudes. This fact may be interpreted as encouraging involvement of stronger fingers in tasks requiring higher total force magnitude production. (b) The finger forces were distributed on a 2-dimensional plane in the 4-dimensional finger force space, which has been confirmed for all subjects and all testing sessions. (c) The discovered principal components in the principal component analysis of the finger forces agreed well with the principle of superposition, i.e. the complex action of

  15. Oro-facial functions in experimental models of cerebral palsy: a systematic review.

    PubMed

    Lacerda, D C; Ferraz-Pereira, K N; Bezerra de Morais, A T; Costa-de-Santana, B J R; Quevedo, O G; Manhães-de-Castro, R; Toscano, A E

    2017-04-01

    Children who suffer from cerebral palsy (CP) often present comorbidities in the form of oro-facial dysfunctions. Studies in animals have contributed to elaborate potential therapies aimed at minimising the chronic disability of the syndrome. To systematically review the scientific literature regarding the possible effects that experimental models of CP can have on oro-facial functions. Two independent authors conducted a systematic review in the electronic databases Medline, Scopus, CINAHL, Web of Science and Lilacs, using Mesh and Decs terms in animal models. The motor and sensory parameters of sucking, chewing and swallowing were considered as primary outcomes; reactivity odour, controlled salivation, postural control, head mobility during feeding and the animal's ability to acquire food were secondary outcomes. Ten studies were included in the present review. Most studies used rabbits as experimental models of CP, which was induced by either hypoxia-ischemia, inflammation or intraventricular haemorrhage. Oro-facial functions were altered in all experimental models of CP. However, we found more modifications in hypoxia-ischemia models overall. On the other hand, the model of inflammation was more effective to reproduce higher damage for coordinating sucking and swallowing. All of the CP experimental models that were assessed modified the oral functions in different animal species. However, further studies should be conducted in order to clarify the mechanisms underlying oro-facial damage in order to optimise treatment strategies for children who suffer from CP.

  16. Experimental approaches for addressing fundamental biological questions in living, functioning cells with single molecule precision.

    PubMed

    Lenn, Tchern; Leake, Mark C

    2012-06-01

    In recent years, single molecule experimentation has allowed researchers to observe biological processes at the sensitivity level of single molecules in actual functioning, living cells, thereby allowing us to observe the molecular basis of the key mechanistic processes in question in a very direct way, rather than inferring these from ensemble average data gained from traditional molecular and biochemical techniques. In this short review, we demonstrate the impact that the application of single molecule bioscience experimentation has had on our understanding of various cellular systems and processes, and the potential that this approach has for the future to really address very challenging and fundamental questions in the life sciences.

  17. Validation of experimental molecular crystal structures with dispersion-corrected density functional theory calculations.

    PubMed

    van de Streek, Jacco; Neumann, Marcus A

    2010-10-01

    This paper describes the validation of a dispersion-corrected density functional theory (d-DFT) method for the purpose of assessing the correctness of experimental organic crystal structures and enhancing the information content of purely experimental data. 241 experimental organic crystal structures from the August 2008 issue of Acta Cryst. Section E were energy-minimized in full, including unit-cell parameters. The differences between the experimental and the minimized crystal structures were subjected to statistical analysis. The r.m.s. Cartesian displacement excluding H atoms upon energy minimization with flexible unit-cell parameters is selected as a pertinent indicator of the correctness of a crystal structure. All 241 experimental crystal structures are reproduced very well: the average r.m.s. Cartesian displacement for the 241 crystal structures, including 16 disordered structures, is only 0.095 Å (0.084 Å for the 225 ordered structures). R.m.s. Cartesian displacements above 0.25 A either indicate incorrect experimental crystal structures or reveal interesting structural features such as exceptionally large temperature effects, incorrectly modelled disorder or symmetry breaking H atoms. After validation, the method is applied to nine examples that are known to be ambiguous or subtly incorrect.

  18. Reconstruction of the unknown optimization cost functions from experimental recordings during static multi-finger prehension

    PubMed Central

    Niu, Xun; Terekhov, Alexander V.; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2013-01-01

    The goal of the research is to reconstruct the unknown cost (objective) function(s) presumably used by the neural controller for sharing the total force among individual fingers in multi-finger prehension. The cost function was determined from experimental data by applying the recently developed Analytical Inverse Optimization (ANIO) method (Terekhov et al 2010). The core of the ANIO method is the Theorem of Uniqueness that specifies conditions for unique (with some restrictions) estimation of the objective functions. In the experiment, subjects (n=8) grasped an instrumented handle and maintained it at rest in the air with various external torques, loads, and target grasping forces applied to the object. The experimental data recorded from 80 trials showed a tendency to lie on a 2-dimensional hyperplane in the 4-dimensional finger-force space. Because the constraints in each trial were different, such a propensity is a manifestation of a neural mechanism (not the task mechanics). In agreement with the Lagrange principle for the inverse optimization, the plane of experimental observations was close to the plane resulting from the direct optimization. The latter plane was determined using the ANIO method. The unknown cost function was reconstructed successfully for each performer, as well as for the group data. The cost functions were found to be quadratic with non-zero linear terms. The cost functions obtained with the ANIO method yielded more accurate results than other optimization methods. The ANIO method has an evident potential for addressing the problem of optimization in motor control. PMID:22104742

  19. Connectome analysis for pre-operative brain mapping in neurosurgery

    PubMed Central

    Hart, Michael G.; Price, Stephen J.; Suckling, John

    2016-01-01

    Abstract Object: Brain mapping has entered a new era focusing on complex network connectivity. Central to this is the search for the connectome or the brains ‘wiring diagram’. Graph theory analysis of the connectome allows understanding of the importance of regions to network function, and the consequences of their impairment or excision. Our goal was to apply connectome analysis in patients with brain tumours to characterise overall network topology and individual patterns of connectivity alterations. Methods: Resting-state functional MRI data were acquired using multi-echo, echo planar imaging pre-operatively from five participants each with a right temporal–parietal–occipital glioblastoma. Complex networks analysis was initiated by parcellating the brain into anatomically regions amongst which connections were identified by retaining the most significant correlations between the respective wavelet decomposed time-series. Results: Key characteristics of complex networks described in healthy controls were preserved in these patients, including ubiquitous small world organization. An exponentially truncated power law fit to the degree distribution predicted findings of general network robustness to injury but with a core of hubs exhibiting disproportionate vulnerability. Tumours produced a consistent reduction in local and long-range connectivity with distinct patterns of connection loss depending on lesion location. Conclusions: Connectome analysis is a feasible and novel approach to brain mapping in individual patients with brain tumours. Applications to pre-surgical planning include identifying regions critical to network function that should be preserved and visualising connections at risk from tumour resection. In the future one could use such data to model functional plasticity and recovery of cognitive deficits. PMID:27447756

  20. Understanding brain, mind and soul: contributions from neurology and neurosurgery.

    PubMed

    Pandya, Sunil K

    2011-01-01

    Treatment of diseases of the brain by drugs or surgery necessitates an understanding of its structure and functions. The philosophical neurosurgeon soon encounters difficulties when localising the abstract concepts of mind and soul within the tangible 1300-gram organ containing 100 billion neurones. Hippocrates had focused attention on the brain as the seat of the mind. The tabula rasa postulated by Aristotle cannot be localised to a particular part of the brain with the confidence that we can localise spoken speech to Broca's area or the movement of limbs to the contralateral motor cortex. Galen's localisation of imagination, reasoning, judgement and memory in the cerebral ventricles collapsed once it was evident that the functional units-neurones-lay in the parenchyma of the brain. Experiences gained from accidental injuries (Phineas Gage) or temporal lobe resection (William Beecher Scoville); studies on how we see and hear and more recent data from functional magnetic resonance studies have made us aware of the extensive network of neurones in the cerebral hemispheres that subserve the functions of the mind. The soul or atman, credited with the ability to enliven the body, was located by ancient anatomists and philosophers in the lungs or heart, in the pineal gland (Descartes), and generally in the brain. When the deeper parts of the brain came within the reach of neurosurgeons, the brainstem proved exceptionally delicate and vulnerable. The concept of brain death after irreversible damage to it has made all of us aware of 'the cocktail of brain soup and spark' in the brainstem so necessary for life. If there be a soul in each of us, surely, it is enshrined here.

  1. Understanding Brain, Mind and Soul: Contributions from Neurology and Neurosurgery

    PubMed Central

    Pandya, Sunil K.

    2011-01-01

    Treatment of diseases of the brain by drugs or surgery necessitates an understanding of its structure and functions. The philosophical neurosurgeon soon encounters difficulties when localising the abstract concepts of mind and soul within the tangible 1300-gram organ containing 100 billion neurones. Hippocrates had focused attention on the brain as the seat of the mind. The tabula rasa postulated by Aristotle cannot be localised to a particular part of the brain with the confidence that we can localise spoken speech to Broca’s area or the movement of limbs to the contralateral motor cortex. Galen’s localisation of imagination, reasoning, judgement and memory in the cerebral ventricles collapsed once it was evident that the functional units–neurones–lay in the parenchyma of the brain. Experiences gained from accidental injuries (Phineas Gage) or temporal lobe resection (William Beecher Scoville); studies on how we see and hear and more recent data from functional magnetic resonance studies have made us aware of the extensive network of neurones in the cerebral hemispheres that subserve the functions of the mind. The soul or atman, credited with the ability to enliven the body, was located by ancient anatomists and philosophers in the lungs or heart, in the pineal gland (Descartes), and generally in the brain. When the deeper parts of the brain came within the reach of neurosurgeons, the brainstem proved exceptionally delicate and vulnerable. The concept of brain death after irreversible damage to it has made all of us aware of ‘the cocktail of brain soup and spark’ in the brainstem so necessary for life. If there be a soul in each of us, surely, it is enshrined here. PMID:21694966

  2. Experimental Approaches for Defining Functional Roles of Microbes in the Human Gut

    PubMed Central

    Dantas, Gautam; Sommer, Morten O.A.; Degnan, Patrick H.; Goodman, Andrew L.

    2016-01-01

    The complex and intimate relationship between humans and their gut microbial communities is becoming less obscure, due in part to large-scale gut microbial genome-sequencing projects and culture-independent surveys of the composition and gene content of these communities. These studies build upon, and are complemented by, experimental efforts to define underlying mechanisms of host-microbe interactions in simplified model systems. This review highlights the intersection of these approaches. Experimental studies now leverage the advances in high-throughput DNA sequencing that have driven the explosion of microbial genome and community profiling projects, and the loss-of-function and gain-of-function strategies long employed in model organisms are now being extended to microbial genes, species, and communities from the human gut. These developments promise to deepen our understanding of human gut host–microbiota relationships and are readily applicable to other host-associated and free-living microbial communities. PMID:24024637

  3. Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for liquid mixtures

    PubMed Central

    2015-01-01

    Kirkwood-Buff or Fluctuation Solution Theory can be used to provide experimental pair fluctuations, and/or integrals over the pair distribution functions, from experimental thermodynamic data on liquid mixtures. Here, this type of approach is used to provide triplet and quadruplet fluctuations, and the corresponding integrals over the triplet and quadruplet distribution functions, in a purely thermodynamic manner that avoids the use of structure factors. The approach is then applied to binary mixtures of water + methanol and benzene + methanol over the full composition range under ambient conditions. The observed correlations between the different species vary significantly with composition. The magnitude of the fluctuations and integrals appears to increase as the number of the most polar molecule involved in the fluctuation or integral also increases. A simple physical picture of the fluctuations is provided to help rationalize some of these variations. PMID:25747091

  4. Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for liquid mixtures

    SciTech Connect

    Ploetz, Elizabeth A.; Smith, Paul E.

    2015-03-07

    Kirkwood-Buff or Fluctuation Solution Theory can be used to provide experimental pair fluctuations, and/or integrals over the pair distribution functions, from experimental thermodynamic data on liquid mixtures. Here, this type of approach is used to provide triplet and quadruplet fluctuations, and the corresponding integrals over the triplet and quadruplet distribution functions, in a purely thermodynamic manner that avoids the use of structure factors. The approach is then applied to binary mixtures of water + methanol and benzene + methanol over the full composition range under ambient conditions. The observed correlations between the different species vary significantly with composition. The magnitude of the fluctuations and integrals appears to increase as the number of the most polar molecule involved in the fluctuation or integral also increases. A simple physical picture of the fluctuations is provided to help rationalize some of these variations.

  5. Experimental demonstration of programmable multi-functional spin logic cell based on spin Hall effect

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Wan, C. H.; Yuan, Z. H.; Fang, C.; Kong, W. J.; Wu, H.; Zhang, Q. T.; Tao, B. S.; Han, X. F.

    2017-04-01

    Confronting with the gigantic volume of data produced every day, raising integration density by reducing the size of devices becomes harder and harder to meet the ever-increasing demand for high-performance computers. One feasible path is to actualize more logic functions in one cell. In this respect, we experimentally demonstrate a prototype spin-orbit torque based spin logic cell integrated with five frequently used logic functions (AND, OR, NOT, NAND and NOR). The cell can be easily programmed and reprogrammed to perform desired function. Furthermore, the information stored in cells is symmetry-protected, making it possible to expand into logic gate array where the cell can be manipulated one by one without changing the information of other undesired cells. This work provides a prospective example of multi-functional spin logic cell with reprogrammability and nonvolatility, which will advance the application of spin logic devices.

  6. Electrocatalysis of borohydride oxidation: a review of density functional theory approach combined with experimental validation

    NASA Astrophysics Data System (ADS)

    Sison Escaño, Mary Clare; Lacdao Arevalo, Ryan; Gyenge, Elod; Kasai, Hideaki

    2014-09-01

    The electrocatalysis of borohydride oxidation is a complex, up-to-eight-electron transfer process, which is essential for development of efficient direct borohydride fuel cells. Here we review the progress achieved by density functional theory (DFT) calculations in explaining the adsorption of BH4- on various catalyst surfaces, with implications for electrocatalyst screening and selection. Wherever possible, we correlate the theoretical predictions with experimental findings, in order to validate the proposed models and to identify potential directions for further advancements.

  7. German Emergency Care in Neurosurgery and Military Neurology during World War II, 1939-1945.

    PubMed

    Stahnisch, Frank W

    2016-01-01

    A critical analysis of the historical involvement of neurology and neurosurgery in military emergency care services enables us to better contextualize and appreciate the development of modern neurology at large. Wartime neurosurgery and civil brain science during the German Nazi period tightly coalesced in examining the specific injury types, which military neurosurgeons such as Wilhelm Toennis, Klaus Joachim Zuelch, and Georg Merrem encountered and treated based on their neurophysiological understanding gained from earlier peacetime research. Collaborative associations with Dr. Toennis in particular proved to be highly beneficial to other military neurologists and neurosurgeons during World War II and beyond. This article also discusses the prewar developments and considers the fate of German neurosurgeons and military neurologists after the war. The envisaged dynamic concepts of fast action, reaction, and recycling, which contemporary physicians had intensively studied in the preceding scientific experiments in their neurophysiological laboratories, had already been introduced into neurological surgery during the interwar period. In retrospect, World War II emergency rescue units greatly strengthened military operations through an active process of 'recycling' indispensable army personnel. Neurosurgical emergency chains thereby introduced another decisive step in the modernization of warfare, in that they increased the momentum of military mobility in the field. Notwithstanding the violence of warfare and the often inhumane ways in which such knowledge in the field of emergency neurology was gained, the protagonists among the group of experts in military neurology and neurosurgery strongly contributed to the postwar clinical neuroscience community in Germany. In differing political pretexts, this became visible in both East Germany and West Germany after the war, while the specific military and political conditions under which this knowledge of emergency medicine

  8. Hand-tool-tissue interaction forces in neurosurgery for haptic rendering.

    PubMed

    Aggravi, Marco; De Momi, Elena; DiMeco, Francesco; Cardinale, Francesco; Casaceli, Giuseppe; Riva, Marco; Ferrigno, Giancarlo; Prattichizzo, Domenico

    2016-08-01

    Haptics provides sensory stimuli that represent the interaction with a virtual or tele-manipulated object, and it is considered a valuable navigation and manipulation tool during tele-operated surgical procedures. Haptic feedback can be provided to the user via cutaneous information and kinesthetic feedback. Sensory subtraction removes the kinesthetic component of the haptic feedback, having only the cutaneous component provided to the user. Such a technique guarantees a stable haptic feedback loop, while it keeps the transparency of the tele-operation system high, which means that the system faithfully replicates and render back the user's directives. This work focuses on checking whether the interaction forces during a bench model neurosurgery operation can lie in the solely cutaneous perception of the human finger pads. If this assumption is found true, it would be possible to exploit sensory subtraction techniques for providing surgeons with feedback from neurosurgery. We measured the forces exerted to surgical tools by three neurosurgeons performing typical actions on a brain phantom, using contact force sensors, while the forces exerted by the tools to the phantom tissue were recorded using a load cell placed under the brain phantom box. The measured surgeon-tool contact forces were 0.01-3.49 N for the thumb and 0.01-6.6 N for index and middle finger, whereas the measured tool-tissue interaction forces were from six to 11 times smaller than the contact forces, i.e., 0.01-0.59 N. The measurements for the contact forces fit the range of the cutaneous sensitivity for the human finger pad; thus, we can say that, in a tele-operated robotic neurosurgery scenario, it would possible to render forces at the fingertip level by conveying haptic cues solely through the cutaneous channel of the surgeon's finger pads. This approach would allow high transparency and high stability of the haptic feedback loop in a tele-operation system.

  9. Functional Inference of Complex Anatomical Tendinous Networks at a Macroscopic Scale via Sparse Experimentation

    PubMed Central

    Saxena, Anupam; Lipson, Hod; Valero-Cuevas, Francisco J.

    2012-01-01

    In systems and computational biology, much effort is devoted to functional identification of systems and networks at the molecular-or cellular scale. However, similarly important networks exist at anatomical scales such as the tendon network of human fingers: the complex array of collagen fibers that transmits and distributes muscle forces to finger joints. This network is critical to the versatility of the human hand, and its function has been debated since at least the 16th century. Here, we experimentally infer the structure (both topology and parameter values) of this network through sparse interrogation with force inputs. A population of models representing this structure co-evolves in simulation with a population of informative future force inputs via the predator-prey estimation-exploration algorithm. Model fitness depends on their ability to explain experimental data, while the fitness of future force inputs depends on causing maximal functional discrepancy among current models. We validate our approach by inferring two known synthetic Latex networks, and one anatomical tendon network harvested from a cadaver's middle finger. We find that functionally similar but structurally diverse models can exist within a narrow range of the training set and cross-validation errors. For the Latex networks, models with low training set error [<4%] and resembling the known network have the smallest cross-validation errors [∼5%]. The low training set [<4%] and cross validation [<7.2%] errors for models for the cadaveric specimen demonstrate what, to our knowledge, is the first experimental inference of the functional structure of complex anatomical networks. This work expands current bioinformatics inference approaches by demonstrating that sparse, yet informative interrogation of biological specimens holds significant computational advantages in accurate and efficient inference over random testing, or assuming model topology and only inferring parameters values. These

  10. Downregulation of FoxC2 Increased Susceptibility to Experimental Colitis: Influence of Lymphatic Drainage Function?

    PubMed Central

    Becker, Felix; Potepalov, Sergey; Shehzahdi, Romana; Bernas, Michael; Witte, Marlys; Abreo, Fleurette; Traylor, James; Orr, Wayne A.; Tsunoda, Ikuo

    2015-01-01

    Background: Although inflammation-induced expansion of the intestinal lymphatic vasculature (lymphangiogenesis) is known to be a crucial event in limiting inflammatory processes, through clearance of interstitial fluid and immune cells, considerably less is known about the impact of an impaired lymphatic clearance function (as seen in inflammatory bowel diseases) on this cascade. We aimed to investigate whether the impaired intestinal lymphatic drainage function observed in FoxC2(+/−) mice would influence the course of disease in a model of experimental colitis. Methods: Acute dextran sodium sulfate colitis was induced in wild-type and haploinsufficient FoxC2(+/−) mice, and survival, disease activity, colonic histopathological injury, neutrophil, T-cell, and macrophage infiltration were evaluated. Functional and structural changes in the intestinal lymphatic vessel network were analyzed, including submucosal edema, vessel morphology, and lymphatic vessel density. Results: We found that FoxC2 downregulation in FoxC2(+/−) mice significantly increased the severity and susceptibility to experimental colitis, as displayed by lower survival rates, increased disease activity, greater histopathological injury, and elevated colonic neutrophil, T-cell, and macrophage infiltration. These findings were accompanied by structural (dilated torturous lymphatic vessels) and functional (greater submucosal edema, higher immune cell burden) changes in the intestinal lymphatic vasculature. Conclusions: These results indicate that sufficient lymphatic clearance plays a crucial role in limiting the initiation and perpetuation of experimental colitis and those disturbances in the integrity of the intestinal lymphatic vessel network could intensify intestinal inflammation. Future therapies might be able to exploit these processes to restore and maintain adequate lymphatic clearance function in inflammatory bowel disease. PMID:25822012

  11. The impact of incomplete knowledge on evaluation: an experimental benchmark for protein function prediction

    PubMed Central

    Huttenhower, Curtis; Hibbs, Matthew A.; Myers, Chad L.; Caudy, Amy A.; Hess, David C.; Troyanskaya, Olga G.

    2009-01-01

    Motivation: Rapidly expanding repositories of highly informative genomic data have generated increasing interest in methods for protein function prediction and inference of biological networks. The successful application of supervised machine learning to these tasks requires a gold standard for protein function: a trusted set of correct examples, which can be used to assess performance through cross-validation or other statistical approaches. Since gene annotation is incomplete for even the best studied model organisms, the biological reliability of such evaluations may be called into question. Results: We address this concern by constructing and analyzing an experimentally based gold standard through comprehensive validation of protein function predictions for mitochondrion biogenesis in Saccharomyces cerevisiae. Specifically, we determine that (i) current machine learning approaches are able to generalize and predict novel biology from an incomplete gold standard and (ii) incomplete functional annotations adversely affect the evaluation of machine learning performance. While computational approaches performed better than predicted in the face of incomplete data, relative comparison of competing approaches—even those employing the same training data—is problematic with a sparse gold standard. Incomplete knowledge causes individual methods' performances to be differentially underestimated, resulting in misleading performance evaluations. We provide a benchmark gold standard for yeast mitochondria to complement current databases and an analysis of our experimental results in the hopes of mitigating these effects in future comparative evaluations. Availability: The mitochondrial benchmark gold standard, as well as experimental results and additional data, is available at http://function.princeton.edu/mitochondria Contact: ogt@cs.princeton.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:19561015

  12. Computational Modeling for Enhancing Soft Tissue Image Guided Surgery: An Application in Neurosurgery

    PubMed Central

    Miga, Michael I.

    2016-01-01

    With the recent advances in computing, the opportunities to translate computational models to more integrated roles in patient treatment are expanding at an exciting rate. One area of considerable development has been directed towards correcting soft tissue deformation within image guided neurosurgery applications. This review captures the efforts that have been undertaken towards enhancing neuronavigation by the integration of soft tissue biomechanical models, imaging and sensing technologies, and algorithmic developments. In addition, the review speaks to the evolving role of modeling frameworks within surgery and concludes with some future directions beyond neurosurgical applications. PMID:26354118

  13. Innovation in Neurosurgery: Intellectual Property Strategy and Academia/Industrial Collaboration.

    PubMed

    Murayama, Yuichi

    2016-09-15

    Neurosurgery has tremendous possibilities for development of innovative medical devices. However, most of the neurosurgical devices used in Japan are imported products. Promotion and development of domestic medical devices is highly encouraged and it is one of the pillars of Prime Minister Shinzo Abe's growth strategy of Japanese economy. Innovative "Made in Japan" medical devices can be developed by interdisciplinary collaboration between industries and academic institutions. Proper orientation of medical and engineering education, social and administrative awareness of the need of facilitating the medical devices creative process with corresponding regulatory changes, and appropriate medical and technological infrastructure establishment are needed for stimulating medical device innovation.

  14. Health-related quality of life outcomes and level of evidence in pediatric neurosurgery.

    PubMed

    Hansen, Daniel; Vedantam, Aditya; Briceño, Valentina; Lam, Sandi K; Luerssen, Thomas G; Jea, Andrew

    2016-10-01

    OBJECTIVE The emphasis on health-related quality of life (HRQOL) outcomes is increasing, along with an emphasis on evidence-based medicine. However, there is a notable paucity of validated HRQOL instruments for the pediatric population. Furthermore, no standardization or consensus currently exists concerning which HRQOL outcome measures ought to be used in pediatric neurosurgery. The authors wished to identify HRQOL outcomes used in pediatric neurosurgery research over the past 10 years, their frequency, and usage trends. METHODS Three top pediatric neurosurgical journals were reviewed for the decade from 2005 to 2014 for clinical studies of pediatric neurosurgical procedures that report HRQOL outcomes. Similar studies in the peer-reviewed journal Pediatrics were also used as a benchmark. Publication year, level of evidence, and HRQOL outcomes were collected for each article. RESULTS A total of 31 HRQOL studies were published in the pediatric neurosurgical literature over the study period. By comparison, there were 55 such articles in Pediatrics. The number of publications using HRQOL instruments showed a significant positive trend over time for Pediatrics (B = 0.62, p = 0.02) but did not increase significantly over time for the 3 neurosurgical journals (B = 0.12, p = 0.5). The authors identified a total of 46 different HRQOL instruments used across all journals. Within the neurosurgical journals, the Hydrocephalus Outcome Questionnaire (HOQ) (24%) was the most frequently used, followed by the Health Utilities Index (HUI) (16%), the Pediatric Quality of Life Inventory (PedsQL) (12%), and the 36-Item Short Form Health Survey (SF-36) (12%). Of the 55 articles identified in Pediatrics, 22 (40%) used a version of the PedsQL. No neurosurgical study reached above Level 4 on the Oxford Centre for Evidence-Based Medicine (OCEBM) system. However, multiple studies from Pediatrics achieved OCEBM Level 3, several were categorized as Level 2, and one reached Level 1

  15. Innovation in Neurosurgery: Intellectual Property Strategy and Academia/Industrial Collaboration

    PubMed Central

    MURAYAMA, Yuichi

    2016-01-01

    Neurosurgery has tremendous possibilities for development of innovative medical devices. However, most of the neurosurgical devices used in Japan are imported products. Promotion and development of domestic medical devices is highly encouraged and it is one of the pillars of Prime Minister Shinzo Abe’s growth strategy of Japanese economy. Innovative “Made in Japan” medical devices can be developed by interdisciplinary collaboration between industries and academic institutions. Proper orientation of medical and engineering education, social and administrative awareness of the need of facilitating the medical devices creative process with corresponding regulatory changes, and appropriate medical and technological infrastructure establishment are needed for stimulating medical device innovation. PMID:27298262

  16. [The processing of point clouds for brain deformation existing in image guided neurosurgery system].

    PubMed

    Yao, Xufeng; Lin, Yixun; Song, Zhijian

    2008-08-01

    The finite element method (FEM) plays an important role in solving the brain deformation problem in the image guided neurosurgery system. The position of the brain cortex during the surgery provides the boundary condition for the FEM model. In this paper, the information of brain cortex is represented by the unstructured points and the boundary condition is achieved by the processing of unstructured points. The processing includes the mapping of texture, segmentation, simplification and denoising. The method of k-nearest clustering based on local surface properties is used to simplify and denoise the unstructured point clouds. The results of experiment prove the efficiency of point clouds processing.

  17. Objective skill analysis and assessment in neurosurgery by using an ultra-miniaturized inertial measurement unit WB-3--pilot tests.

    PubMed

    Lin, Z; Zecca, M; Sessa, S; Sasaki, T; Suzuki, T; Itoh, K; Iseki, H; Takanishi, A

    2009-01-01

    In recent years there has been an ever increasing amount of research and development of technologies and methods to improve the quality and the performance of advanced surgery. In several fields, such as laparoscopy, various training methods and metrics have been proposed, both to improve the surgeon's abilities and also to assess her/his skills. For neurosurgery, however, the extremely small movements and target operating space involved have prevented until now the development of similar methodologies and systems. In this paper we present the development of an ultra-miniaturized Inertial Measurement Unit (IMU) and its application for neurosurgery skill assessment in a simple pick and place scenario. This analysis is a preliminary yet fundamental step to realize a better training/evaluation system for neurosurgeons, and to objectively evaluate and understand how the neurosurgery is performed.

  18. Current Applications and Future Perspectives of the Use of 3D Printing in Anatomical Training and Neurosurgery.

    PubMed

    Baskaran, Vivek; Štrkalj, Goran; Štrkalj, Mirjana; Di Ieva, Antonio

    2016-01-01

    3D printing is a form of rapid prototyping technology, which has led to innovative new applications in biomedicine. It facilitates the production of highly accurate three dimensional objects from substrate materials. The inherent accuracy and other properties of 3D printing have allowed it to have exciting applications in anatomy education and surgery, with the specialty of neurosurgery having benefited particularly well. This article presents the findings of a literature review of the Pubmed and Web of Science databases investigating the applications of 3D printing in anatomy and surgical education, and neurosurgery. A number of applications within these fields were found, with many significantly improving the quality of anatomy and surgical education, and the practice of neurosurgery. They also offered advantages over existing approaches and practices. It is envisaged that the number of useful applications will rise in the coming years, particularly as the costs of this technology decrease and its uptake rises.

  19. Current Applications and Future Perspectives of the Use of 3D Printing in Anatomical Training and Neurosurgery

    PubMed Central

    Baskaran, Vivek; Štrkalj, Goran; Štrkalj, Mirjana; Di Ieva, Antonio

    2016-01-01

    3D printing is a form of rapid prototyping technology, which has led to innovative new applications in biomedicine. It facilitates the production of highly accurate three dimensional objects from substrate materials. The inherent accuracy and other properties of 3D printing have allowed it to have exciting applications in anatomy education and surgery, with the specialty of neurosurgery having benefited particularly well. This article presents the findings of a literature review of the Pubmed and Web of Science databases investigating the applications of 3D printing in anatomy and surgical education, and neurosurgery. A number of applications within these fields were found, with many significantly improving the quality of anatomy and surgical education, and the practice of neurosurgery. They also offered advantages over existing approaches and practices. It is envisaged that the number of useful applications will rise in the coming years, particularly as the costs of this technology decrease and its uptake rises. PMID:27445707

  20. A Comparison of Experimental Functional Analysis and the Questions about Behavioral Function (QABF) in the Assessment of Challenging Behavior of Individuals with Autism

    ERIC Educational Resources Information Center

    Healy, Olive; Brett, Denise; Leader, Geraldine

    2013-01-01

    We compared two functional behavioral assessment methods: the Questions About Behavioral Function (QABF; a standardized test) and experimental functional analysis (EFA) to identify behavioral functions of aggressive/destructive behavior, self-injurious behavior and stereotypy in 32 people diagnosed with autism. Both assessments found that self…

  1. Isocentric stereotactic three-dimensional digitizer for neurosurgery.

    PubMed

    Takizawa, T

    1993-01-01

    A new system has been developed, comprising a frameless isocentric stereotactic mechanism and a three-dimensional (3-D) digitizer for intraoperative spatial monitoring. The 3-D digitizer's multiarticulated arm has three joints related to Cartesian coordinates, two quadrant arcs forming an isocenter system, a microdrive, and a probe holder. The frameless isocentric mechanism is useful for open stereotaxy. Routine CT- or MRI-guided stereotactic surgery is also possible, due to the high level of accuracy of the system. Before surgery, CT and/or MR images are acquired after placing on the scalp three or four external markers. For surgical procedures which require high accuracy, Laitinen's noninvasive CT or MRI localizing markers are used. CT or MR images are entered into a computer using an image scanner, and are stored on a floppy disk. After the patient's head is fixed to the operating table using a Mayfield clamp, the 3-D digitizer is used to read the spatial points and external markers on the scalp or the reference points of Laitinen's localizing markers. During the procedure, the coordinates on the patient's head are automatically entered into the computer and matched with those of the 3-D digitizer and CT/MR images on the CRT display. This system has been used in 22 cases of open craniotomy and 33 cases of burr hole surgery, both carried out using the stereotactic function and the 3-D spatial monitoring function in parallel. Errors in mechanical accuracy of the 3-D digitizer were less than 0.8 mm, and the maximum error during operation was presumed not to exceed 2 mm.

  2. Alfvénic oscillations of the electron distribution function: Linear theory and experimental measurements

    SciTech Connect

    Schroeder, J. W. R. Skiff, F.; Howes, G. G.; Kletzing, C. A.; Carter, T. A.; Dorfman, S.

    2015-12-10

    Wave propagation can be an accurate method for determining material properties. High frequency whistler mode waves (0.7 < ω/|Ω{sub ce}| < 1) in an overdense plasma (ω{sub pe} > |Ω{sub ce}|) are damped primarily by Doppler-shifted electron cyclotron resonance. A kinetic description of whistler mode propagation parallel to the background magnetic field shows that damping is proportional to the parallel electron distribution function. This property enables an experimental determination of the parallel electron distribution function using a measurement of whistler mode wave absorption. The whistler mode wave absorption diagnostic uses this technique on UCLA’s Large Plasma Device (LaPD) to measure the distribution of high energy electrons (5 − 10v{sub te}) with 0.1% precision. The accuracy is limited by systematic effects that need to be considered carefully. Ongoing research uses this diagnostic to investigate the effect of inertial Alfvén waves on the electron distribution function. Results presented here verify experimentally the linear effects of inertial Alfvén waves on the reduced electron distribution function, a necessary step before nonlinear physics can be tested. Ongoing experiments with the whistler mode wave absorption diagnostic are making progress toward the first direct detection of electrons nonlinearly accelerated by inertial Alfvén waves, a process believed to play an important role in auroral generation.

  3. Preliminary Results on the Experimental Investigation of the Structure Functions of Bound Nucleons

    SciTech Connect

    Bodek, Arie

    2015-09-01

    We present preliminary results on an experimental study of the nuclear modification of the longitudinal (σL) and transverse (σT) structure functions of nucleons bound in nuclear targets. The origin of these modifications (commonly referred as as the EMC effect) is not fully understood. Our measurements of R= σLT for nuclei (RA) and for deuterium (RD) indicate that nuclear modifications of the structure functions of bound nucleons are different for the longitudinal and transverse structure functions, and that contrary to expectation from several theoretical models, RA < RD.

  4. Functional MRI and diffusion tensor imaging of brain reorganization after experimental stroke.

    PubMed

    Dijkhuizen, Rick M; van der Marel, Kajo; Otte, Willem M; Hoff, Erik I; van der Zijden, Jet P; van der Toorn, Annette; van Meer, Maurits P A

    2012-03-01

    The potential of the adult brain to reorganize after ischemic injury is critical for functional recovery and provides a significant target for therapeutic strategies to promote brain repair. Despite the accumulating evidence of brain plasticity, the interaction and significance of morphological and physiological modifications in post-stroke brain tissue remain mostly unclear. Neuroimaging techniques such as functional MRI (fMRI) and diffusion tensor imaging (DTI) enable in vivo assessment of the spatial and temporal pattern of functional and structural changes inside and outside ischemic lesion areas. This can contribute to the elucidation of critical aspects in post-stroke brain remodeling. Task/stimulus-related fMRI, resting-state fMRI, or pharmacological MRI enables direct or indirect measurement of neuronal activation, functional connectivity, or neurotransmitter system responses, respectively. DTI allows estimation of the structural integrity and connectivity of white matter tracts. Together, these MRI methods provide an unprecedented means to (a) measure longitudinal changes in tissue structure and function close by and remote from ischemic lesion areas, (b) evaluate the organizational profile of neural networks after stroke, and (c) identify degenerative and restorative processes that affect post-stroke functional outcome. Besides, the availability of MRI in clinical institutions as well as research laboratories provides an optimal basis for translational research on stroke recovery. This review gives an overview of the current status and perspectives of fMRI and DTI applications to study brain reorganization in experimental stroke models.

  5. From the Idea to Its Realization: The Evolution of Minimally Invasive Techniques in Neurosurgery

    PubMed Central

    Grunert, P.

    2013-01-01

    Minimally invasive techniques in neurosurgery evolved in two steps. Many minimally invasive concepts like neuronavigation, endoscopy, or frame based stereotaxy were developed by the pioneers of neurosurgery, but it took decades till further technical developments made the realization and broad clinical application of these early ideas safe and possible. This thesis will be demonstrated by giving examples of the evolution of four minimally invasive techiques: neuronavigation, transsphenoidal pituitary surgery, neuroendoscopy and stereotaxy. The reasons for their early failure and also the crucial steps for the rediscovery of these minimally invasive techniques will be analysed. In the 80th of the 20th century endoscopy became increasingly applied in different surgical fields. The abdominal surgeons coined as first for their endoscopic procedures the term minimally invasive surgery in contrast to open surgery. In neurrosurgery the term minimally invasive surgery stood not in opposiotion to open procedures but was understood as a general concept and philosophy using the modern technology such as neuronavigation, endoscopy and planing computer workstations with the aim to make the procedures less traumatic. PMID:24455231

  6. Schizophrenia and neurosurgery: A dark past with hope of a brighter future.

    PubMed

    Agarwal, Prateek; Sarris, Christina E; Herschman, Yehuda; Agarwal, Nitin; Mammis, Antonios

    2016-12-01

    Schizophrenia is a chronic and progressive psychiatric disease that remains difficult to manage in the 21st century. Current medical therapies have been able to give reprieve and decrease incidence of psychotic episodes. However, as the disease progresses, patients can become ever more refractory to current pharmaceutical agents and the polypharmacy that is attempted in treatment. Additionally, many of these drugs have significant adverse effects, leaving the practitioner in a difficult predicament for treating these patients. The history of neurosurgery for schizophrenia, among other psychiatric diseases, has a very dark past. Therefore, this review examines peer-reviewed studies on the history of schizophrenia, its medical and surgical therapies, financial costs, and future directions for disease management. We highlight the historically poor relationship between neurosurgery and psychiatric disease and discuss current research in the understandings of schizophrenia. Guided by a strong code of ethics and new technology, including the use of stereotaxis and deep brain stimulation (DBS), the medical communities treating psychiatric disease are beginning to overcome the horrors of the past. DBS is currently being used with moderate success in the treatment of depression, obsessive compulsive disorder, Tourette's syndrome, and anorexia nervosa. With greater understanding of the neural circuitry of schizophrenia and the evolving role for DBS in psychiatric disease, the authors believe that schizophrenia, like other psychiatric diseases, can be treated with DBS.

  7. Preventable and Potentially Preventable Traumatic Death Rates in Neurosurgery Department: A Single Center Experience

    PubMed Central

    Ha, Mahnjeong; Kim, Byung Chul; Choi, Seonuoo; Cho, Won Ho

    2016-01-01

    Objective Preventable and potentially preventable traumatic death rates is a method to evaluate the preventability of the traumatic deaths in emergency medical department. To evaluate the preventability of the traumatic deaths in patients who were admitted to neurosurgery department, we performed this study. Methods A retrospective review identified 52 patients who admitted to neurosurgery department with severe traumatic brain injuries between 2013 and 2014. Based on radiologic and clinical state at emergency room, each preventability of death was estimated by professional panel discussion. And the final death rates were calculated. Results The preventable and potentially preventable traumatic death rates was 19.2% in this study. This result is lower than that of the research of 2012, Korean preventable and potentially preventable traumatic death rates. The rate of preventable and potentially preventable traumatic death of operation group is lower than that of conservative treatment group. Also, we confirmed that direct transfer and the time to operation are important to reduce the preventability. Conclusion We report the preventable and potentially preventable traumatic death rates of our institute for evaluation of preventability in severe traumatic brain injuries during the last 2 years. For decrease of preventable death, we suggest that continuous survey of the death rate of traumatic brain injury patients is required. PMID:27857910

  8. Methods for exploring the morpho-functional relations of the aortic depressor nerve in experimental diabetes.

    PubMed

    do Carmo, Jussara Márcia; Júnior, Rubens Fazan; Salgado, Helio Cesar; Fazan, Valéria Paula Sassoli

    2011-01-30

    The present study investigated morpho-functional relations of the aortic depressor nerve (ADN) 5, 15 and 120 days after the onset of streptozotocin-induced diabetes in rats. Time control animals received vehicle. Under pentobarbital anesthesia, ADN activity was recorded simultaneously with arterial pressure. After the recordings, nerves were prepared for light microscopy study and morphometry. ADN function was accessed by means of pressure-nerve activity curve (fitted by sigmoidal regression) and cross-spectral analysis between mean arterial pressure (MAP) and ADN activity. The relation between morphological (myelinated fibers number and density, total myelin area, total fiber area and percentage of occupancy) and functional (gain, signal/noise relation, frequency) parameters were accessed by linear regression analysis and correlation coefficient calculations. Functional parameters obtained by means of the sigmoidal regression curve as well as by cross-spectral analysis were similar in diabetic and control rats. Morphometric parameters of the ADN were similar between groups 5 days after the onset of diabetes. Average myelin area and myelinated fiber area were significantly smaller on diabetic rats 15 and 120 days after the onset of diabetes, being the myelinated fiber and respective axons area and diameter also smaller on 120 days group. Nevertheless, G ratio (ratio between axon and fiber diameter) was nearly 0.6 and not different between groups or experimental times. No significant relationship between morphological and functional parameters was detected in all experimental groups. The present study suggests that ADN diabetic neuropathy was time-dependent, with damage to myelinated fibers to be the primary event, not evidenced by physiological methods.

  9. Assessing residents' operative skills for external ventricular drain placement and shunt surgery in pediatric neurosurgery.

    PubMed

    Aldave, Guillermo; Hansen, Daniel; Briceño, Valentina; Luerssen, Thomas G; Jea, Andrew

    2017-01-27

    OBJECTIVE The authors previously demonstrated the use of a validated Objective Structured Assessment of Technical Skills (OSATS) tool for evaluating residents' operative skills in pediatric neurosurgery. However, no benchmarks have been established for specific pediatric procedures despite an increased need for meaningful assessments that can either allow for early intervention for underperforming trainees or allow for proficient residents to progress to conducting operations independently with more passive supervision. This validated methodology and tool for assessment of operative skills for common pediatric neurosurgical procedures-external ventricular drain (EVD) placement and shunt surgery- was applied to establish its procedure-based feasibility and reliability, and to document the effect of repetition on achieving surgical skill proficiency in pediatric EVD placement and shunt surgery. METHODS A procedure-based technical skills assessment for EVD placements and shunt surgeries in pediatric neurosurgery was established through the use of task analysis. The authors enrolled all residents from 3 training programs (Baylor College of Medicine, Houston Methodist Hospital, and University of Texas-Medical Branch) who rotated through pediatric neurosurgery at Texas Children's Hospital over a 26-month period. For each EVD placement or shunt procedure performed with a resident, the faculty and resident (for self-assessment) completed an evaluation form (OSATS) based on a 5-point Likert scale with 7 categories. Data forms were then grouped according to faculty versus resident (self) assessment, length of pediatric neurosurgery rotation, postgraduate year level, and date of evaluation ("beginning of rotation," within 1 month of start date; "end of rotation," within 1 month of completion date; or "middle of rotation"). Descriptive statistical analyses were performed with the commercially available SPSS statistical software package. A p value < 0.05 was considered

  10. The Opioid-Sparing Effect of Perioperative Dexmedetomidine Plus Sufentanil Infusion during Neurosurgery: A Retrospective Study

    PubMed Central

    Su, Shiyu; Ren, Chunguang; Zhang, Hongquan; Liu, Zhong; Zhang, Zongwang

    2016-01-01

    Background: Approximately 60% of patients experience moderate-to-severe pain after neurosurgery, which primarily occurs in the first 24–72 h. Despite this, improved postoperative analgesia solutions after neurosurgery have not yet been devised. This retrospective study was conducted to evaluate the effect of intra- and post-operative infusions of dexmedetomidine (DEX) plus sufentanil on the quality of postoperative analgesia in patients undergoing neurosurgery. Methods: One hundred and sixty-three post-neurosurgery patients were divided into two groups: Group D (DEX infusion at 0.5 μg·kg−1 for 10 min, then adjusted to 0.3 μg·kg−1·h−1 until incision suturing) and Group ND (no DEX infusion during surgery). Patient-controlled analgesia was administered for 72 h after surgery (Group D: sufentanil 0.02 μg·kg−1·h−1 plus DEX 0.02 μg·kg−1·h−1, Group ND: sufentanil 0.02 μg·kg−1·h−1) in this retrospective study. The primary outcome measure was postoperative sufentanil consumption. Hemodynamics, requirement of narcotic, and vasoactive drugs, recovery time and the incidence of concerning adverse effects were recorded. Pain intensity [Visual Analogue Scale (VAS)], Ramsay sedation scale (RSS) and Bruggemann comfort scale (BCS) were also evaluated at 1, 4, 8, 12, 24, 48, and 72 h after surgery. Results: Postoperative sufentanil consumption was significantly lower in Group D during the first 72 h after surgery (P < 0.05). Compared with Group ND, heart rate (HR) in Group D was significantly decreased from intubation to 20 min after arriving at post anesthesia care unit (PACU), while mean arterial pressure (MAP) in Group D was significantly decreased from intubation to 5 min after arriving at PACU (P < 0.05). The intraoperative requirements for sevoflurane, remifentanil, and fentanyl were approximately 35% less in Group D compared with Group ND. VAS at rest at 1, 4, and 8 h and with cough at 12, 24, 48, and 72 h after surgery were significantly

  11. Atmospheric channel transfer function estimation from experimental free-space optical communications data

    NASA Astrophysics Data System (ADS)

    Reinhardt, Colin N.; Tsintikidis, Dimitris; Hammel, Stephen; Kuga, Yasuo; Ritcey, James A.; Ishimaru, Akira

    2012-03-01

    Using an 850-nanometer-wavelength free-space optical (FSO)communications system of our own design, we acquired field data for the transmitted and received signals in fog at Point Loma, CA for a range of optical depths within the multiple-scattering regime. Statistical estimators for the atmospheric channel transfer function and the related coherency function were computed directly from the experimental data. We interpret the resulting channel transfer function estimates in terms of the physics of the atmospheric propagation channel and fog aerosol particle distributions. We investigate the behavior of the estimators using both real field-test data and simulated propagation data. We compare the field-data channel transfer function estimates against the outputs from a computationally-intensive radiative-transfer theory model-based approach, which we also developed previously for the FSO multiple-scattering atmospheric channel. Our results show that the data-driven channel transfer function estimates are in close agreement with the radiative transfer modeling, and provide comparable receiver signal detection performance improvements while being significantly less time and computationally-intensive.

  12. Experimental and bioinformatic approaches for interrogating protein-protein interactions to determine protein function.

    PubMed

    Droit, Arnaud; Poirier, Guy G; Hunter, Joanna M

    2005-04-01

    An ambitious goal of proteomics is to elucidate the structure, interactions and functions of all proteins within cells and organisms. One strategy to determine protein function is to identify the protein-protein interactions. The increasing use of high-throughput and large-scale bioinformatics-based studies has generated a massive amount of data stored in a number of different databases. A challenge for bioinformatics is to explore this disparate data and to uncover biologically relevant interactions and pathways. In parallel, there is clearly a need for the development of approaches that can predict novel protein-protein interaction networks in silico. Here, we present an overview of different experimental and bioinformatic methods to elucidate protein-protein interactions.

  13. Electronic and optical response of functionalized Ru(II) complexes: joint theoretical and experimental study

    SciTech Connect

    Kilina, Svetlana; Tretiak, Sergei; Sykora, Milan; Albert, Victor; Badaeva, Ekaterina; Koposov, Alexey

    2008-01-01

    New photovoltaic and photocatalysis applications have been recently proposed based on the hybrid Ru(II)-bipyridine-complex/semiconductor quantum dot systems. In order to attach the Ru(II) complex to the surface of a semiconductor, a linking bridge -- a carboxyl group -- needs to be added to one or two of the 2,2'-bipyridine (bpy) ligands. Such changes in the ligand structure affect electronic and optical properties and, consequently, the charge transfer reactivity of Ru(II)-systems. In this study, we analyze the effects brought by functionalization of bipyridine ligands with the methyl, carboxyl, and carboxilate groups on the electronic structure and optical response of the [Ru(bpy){sub 3}]{sup 2+} complex. First principle calculations based on density functional theory (DFT) and time dependent DFT (TDDFT) are used to simulate the ground and excited-state properties, respectively, of functionalized Ru-complexes in the gas phase and acetonitrile solution. In addition, an effective Frenkel exciton model is used to explain the optical activity and splitting patterns of the low-energy excited states in all molecules. All theoretical results nicely complement and allow for detailed interpretation of experimental absorption spectra of Ru-complexes that have been done in parallel with our theoretical investigations. We found that the carboxyl group breaks the degeneracy of two low-energy optically bright excited states and red-shifts the absorption spectrum, while leaves ionization and affinity energies of complexes almost unchanged. Experimental studies show that deprotonation of the carboxyl group in the Ru-complexes results in a slight blue shift and decrease of oscillator strengths of the low energy absorption peaks. Comparison of experimental and theoretical linear response spectra of deprotonated complexes demonstrate strong agreement if the theoretical calculations are performed with the addition of a dielectric continuum model. A polar solvent is found to play an

  14. Molecular alterations of canalicular transport systems in experimental models of cholestasis: possible functional correlations.

    PubMed Central

    Trauner, M.

    1997-01-01

    The discovery of unidirectional, ATP-dependent canalicular transport systems (also termed "export pumps") for bile salts, amphiphilic anionic conjugates, lipophilic cations, and phospholipids has opened new opportunities for understanding biliary physiology and the pathophysiology of cholestasis. In addition, ATP-independent canalicular transport systems for glutathione and bicarbonate contribute to (bile acid-independent) bile formation. Canalicular excretion of bile salts and several non-bile acid organic anions is impaired in various experimental models of cholestasis. Recent cloning of several canalicular transport systems now facilitates studies on their molecular regulation in cholestasis. Although the picture is far from complete, experimental evidence now exists that decreased or even absent expression of canalicular transport proteins may explain impaired transport function resulting in hyperbilirubinemia and cholestasis. With the increasing availability of molecular probes for these transport systems in humans, new information on the molecular regulation of canalicular transport proteins in human cholestatic liver diseases is beginning to emerge and should bring new insights into their pathophysiology and treatment. This article gives an overview on molecular alterations of canalicular transport systems in experimental models of cholestasis and discusses the potential implications of these changes for the pathophysiology of cholestasis. PMID:9626757

  15. A neurologist in the origin of European and International neurosurgery: Clovis-Julien-Désiré Vincent (1879-1947).

    PubMed

    Androutsos, G; Karamanou, M; Lymberi, M; Zambelis, T; Stamboulis, E

    2011-01-01

    Vincent Clovis began his carrier as a neurologist and finally became neurosurgeon at an advanced age. He is considered the founder of French neurosurgery, and after Harvey Williams Cushing, Europe's first neurosurgeon. He was mainly interested in pituitary tumors, in cerebral abscesses and in cerebral oedema.

  16. Experimental Measurements and Density Functional Theory Calculations of Continuum Lowering in Strongly Coupled Plasmas

    NASA Astrophysics Data System (ADS)

    Vinko, Sam

    2014-10-01

    An accurate description of the ionization potential depression (IPD) of ions in plasmas due to their interaction with the environment is a fundamental problem in plasma physics, playing a key role in determining the ionization balance, charge state distribution, opacity and plasma equation of state. Here I present the first experimental investigation of the IPD as a function of ionic charge state in a range of dense Mg, Al and Si plasmas, using the Linac Coherent Light Source X-ray free-electron laser. The measurements show significantly larger IPDs than are predicted by the most commonly used models, such as that of Stewart-Pyatt, or the ion-sphere model of Zimmerman-More. Instead, plasma simulations using finite-temperature density functional theory with excited-state projector augmented-wave potentials show excellent agreement with the experimental results and explain the stronger-than-expected continuum lowering through the electronic structure of the valence states in these strong-coupling conditions, which retain much of their atomic characteristics close to the ion core regions. These results have a profound impact on the understanding and modelling of plasmas over a wide range of warm- and hot-dense matter conditions.

  17. Regulation of cellular function via electromagnetic field frequency and extracellular environment: A theoretical- experimental approach

    NASA Astrophysics Data System (ADS)

    Taghian, Toloo; Sheikh, Abdul; Narmoneva, Daria; Kogan, Andrei

    2015-03-01

    Application of external electric field (EF) as a non-pharmacological, non-invasive tool to control cell function is of great therapeutic interest. We developed a theoretical-experimental approach to investigate the biophysical mechanisms of EF interaction with cells in electrode-free physiologically-relevant configuration. Our numerical results demonstrated that EF frequency is the major parameter to control cell response to EF. Non-oscillating or low-frequency EF leads to charge accumulation on the cell surface membrane that may mediate membrane initiated cell responses. In contrast, high-frequency EF penetrates the cell membrane and reaches cell cytoplasm, where it may directly activate intracellular responses. The theoretical predictions were confirmed in our experimental studies of the effects of applied EF on vascular cell function. Results show that non-oscillating EF increases vascular endothelial growth factor (VEGF) expression while field polarity controls cell adhesion rate. High-frequency, but not low frequency, EF provides differential regulation of cytoplasmic focal adhesion kinase and VEGF expression depending on the substrate, with increased expression in cells cultured on RGD-rich synthetic hydrogels, and decreased expression for matrigel culture. The authors acknowledge the financial support from the NSF (DMR-1206784 & DMR-0804199 to AK); the NIH (1R21 DK078814-01A1 to DN) and the University of Cincinnati (Interdisciplinary Faculty Research Support Grant to DN and AK).

  18. Experimental modifications imply a stimulatory function for male tsetse fly genitalia, supporting cryptic female choice theory.

    PubMed

    Briceño, R D; Eberhard, William G

    2009-07-01

    One of the most sweeping of all patterns in morphological evolution is that animal genitalia tend to diverge more rapidly than do other structures. Abundant indirect evidence supports the cryptic female choice (CFC) explanation of this pattern, which supposes that male genitalia often function to court females during copulation; but direct experimental demonstrations of a stimulatory function have been lacking. In this study, we altered the form of two male genital structures that squeeze the female's abdomen rhythmically in Glossina pallidipes flies. As predicted by theory, this induced CFC against the male: ovulation and sperm storage decreased, while female remating increased. Further experiments showed that these effects were due to changes in tactile stimuli received by the female from the male's altered genitalia, and were not due to other possible changes in the males due to alteration of their genital form. Stimulation from male genital structures also induces females to permit copulation to occur. Together with previous studies of tsetse reproductive physiology, these data constitute the most complete experimental confirmation that sexual selection (probably by CFC) acts on the stimulatory properties of male genitalia.

  19. Characterizing Molecular Structure by Combining Experimental Measurements with Density Functional Theory Computations

    NASA Astrophysics Data System (ADS)

    Lopez-Encarnacion, Juan M.

    2016-06-01

    In this talk, the power and synergy of combining experimental measurements with density functional theory computations as a single tool to unambiguously characterize the molecular structure of complex atomic systems is shown. Here, we bring three beautiful cases where the interaction between the experiment and theory is in very good agreement for both finite and extended systems: 1) Characterizing Metal Coordination Environments in Porous Organic Polymers: A Joint Density Functional Theory and Experimental Infrared Spectroscopy Study 2) Characterization of Rhenium Compounds Obtained by Electrochemical Synthesis After Aging Process and 3) Infrared Study of H(D)2 + Co4+ Chemical Reaction: Characterizing Molecular Structures. J.M. López-Encarnación, K.K. Tanabe, M.J.A. Johnson, J. Jellinek, Chemistry-A European Journal 19 (41), 13646-13651 A. Vargas-Uscategui, E. Mosquera, J.M. López-Encarnación, B. Chornik, R. S. Katiyar, L. Cifuentes, Journal of Solid State Chemistry 220, 17-21

  20. Comparison between Theoretical Calculation and Experimental Results of Excitation Functions for Production of Relevant Biomedical Radionuclides

    SciTech Connect

    Menapace, E.; Birattari, C.; Bonardi, M.L.; Groppi, F.; Morzenti, S.; Zona, C.

    2005-05-24

    The radionuclide production for biomedical applications has been brought up in the years, as a special nuclear application, at INFN LASA Laboratory, particularly in co-operation with the JRC-Ispra of EC. Mainly scientific aspects concerning radiation detection and the relevant instruments, the measurements of excitation functions of the involved nuclear reactions, the requested radiochemistry studies and further applications have been investigated. On the side of the nuclear data evaluations, based on nuclear model calculations and critically selected experimental data, the appropriate competence has been developed at ENEA Division for Advanced Physics Technologies. A series of high specific activity accelerator-produced radionuclides in no-carrier-added (NCA) form, for uses in metabolic radiotherapy and for PET radiodiagnostics, are investigated. In this work, last revised measurements and model calculations are reviewed for excitation functions of natZn(d,X)64Cu, 66Ga reactions, referring to irradiation experiments at K=38 variable energy Cyclotron of JRC-Ispra. Concerning the reaction data for producing 186gRe and 211At/211gPo (including significant emission spectra) and 210At, most recent and critically selected experimental results are considered and discussed in comparison with model calculations paying special care to pre-equilibrium effects estimate and to the appropriate overall parameterization. Model calculations are presented for 226Ra(p,2n)225Ac reaction, according to the working program of the ongoing IAEA CRP on the matter.

  1. Urban artificial light emission function determined experimentally using night sky images

    NASA Astrophysics Data System (ADS)

    Solano Lamphar, Héctor Antonio; Kocifaj, Miroslav

    2016-09-01

    To date, diverse approximations have been developed to interpret the radiance of a night sky due to light emissions from ground-based light sources. The radiant intensity distribution as a function of zenith angle is one of the most unknown properties because of the collective effects of all artificial, private and public lights. The emission function (EF) is, however, a key property in modeling the skyglow under arbitrary conditions, and thus it is equally required by modelers, light pollution researchers, and also experimentalists who are using specialized devices to study the diffuse light of a night sky. In this paper, we present the second generation of a dedicated measuring system intended for routine monitoring of a night sky in any region. The experimental technology we have developed is used to interpret clear sky radiance data recorded at a set of discrete distances from a town (or city) with the aim to infer the fraction of upwardly emitted light (F), that is a parameter scaling the bulk EF. The retrieval of the direct upward emissions has been improved by introducing a weighting factor that is used to eliminate imperfections of experimental data and thus to make the computation of F more stable when processing the radiance data taken at two adjacent measuring points. The field experiments made in three Mexican cities are analyzed and the differences found are discussed.

  2. Notch signalling suppresses regulatory T-cell function in murine experimental autoimmune uveitis.

    PubMed

    Rong, Hua; Shen, Hongjie; Xu, Yueli; Yang, Hai

    2016-12-01

    Autoimmune uveitis is an intraocular inflammatory disorder in developed countries. Understanding the mechanisms underlying the development and modulation of immune reaction in uveitic eyes is critical for designing therapeutic interventions. Here we investigated the role of Notch signalling in regulatory T-cell (Treg cell) function during experimental autoimmune uveitis (EAU). Using the Foxp3-GFP reporter mouse strain, the significance of Notch signalling for the function of infiltrating Treg cells was characterized in an EAU model. We found that infiltrating Treg cells substantially expressed Notch-1, Notch-2, JAG1 and DLL1 in uveitic eyes. Activation of Notch signalling, represented by expression of HES1 and HES5, was enhanced in infiltrating Treg cells. Treatment with JAG1 and DLL1 down-regulated Foxp3 expression and immunosuppressive activity of isolated infiltrating Treg cells in vitro, whereas neutralizing antibodies against JAG1 and DLL1 diminished Notch ligand-mediated negative effects on Treg cells. To investigate the significance of Notch signalling for Treg cell function in vivo, lentivirus-derived Notch short hairpin RNAs were transduced into in vitro expanded Treg cells before adoptive transfer of Treg cells into EAU mice. Transfer of Notch-1-deficient Treg cells remarkably reduced pro-inflammatory cytokine production and inflammatory cell infiltration in uveitic eyes. Taken together, Notch signalling negatively modulates the immunosuppressive function of infiltrating Treg cells in mouse EAU.

  3. Evaluation of iris functional capillary density in experimental local and systemic inflammation.

    PubMed

    Arora, N; Islam, S; Wafa, K; Zhou, J; Toguri, J T; Cerny, V; Lehmann, C

    2017-04-01

    The ocular microcirculation represents an important target to treat inflammatory diseases of eye, where impairment of microvascular blood flow plays key role as, for example, in anterior uveitis. To evaluate novel interventions targeting the microcirculation, appropriate and reliable tools to study this particular microvascular bed are needed. Intravital microscopy (IVM) belongs to several methods allowing evaluation of microcirculation experimentally, even in small animals. The aim of our study was to examine the iridial microcirculation (IMIC) in uveitis induced by local or systemic endotoxin administration in rats and mice by IVM and to propose new parameters to quantify the changes within the IMIC. Systemic inflammation was induced in rats by intravenous endotoxin administration, control group received normal saline intravenously. Local inflammation was induced in mice by intravitreal endotoxin administration, the control group received normal saline intravitreally. IVM of IMIC was performed in animals receiving systemic endotoxin prior injection and 1 and 2 h afterwards, respectively, in animals receiving intravitreal endotoxin/saline prior local injection and 5 h afterwards. Obtained video recordings were analyzed off-line. Functional capillary density (FCD) and dysfunctional capillary density (DCD) were evaluated for description of IMIC, and calculation of FCD/DCD ratio was performed. In systemic inflammation, FCD was significantly decreased compared to control animals. In local inflammation, the number of functional capillaries in the IMIC was significantly reduced following the endotoxin challenge. Analysis of the DCD revealed a significant increase in capillaries with reduced perfusion after intravitreal endotoxin administration and right shift of the FCD/DCD ratio was observed after endotoxin local injection. Detecting and quantifying changes in IMIC during systemic or local inflammation in experimental animals by IVM was feasible. Therefore, IVM of the

  4. Anatomic and Functional Connectivity Relationship in Autistic Children During Three Different Experimental Conditions.

    PubMed

    Machado, Calixto; Rodríguez, Rafael; Estévez, Mario; Leisman, Gerry; Melillo, Robert; Chinchilla, Mauricio; Portela, Liana

    2015-10-01

    A group of 21 autistic children were studied for determining the relationship between the anatomic (AC) versus functional (FC) connectivity, considering short-range and long-range brain networks. AC was assessed by the DW-MRI technique and FC by EEG coherence calculation, in three experimental conditions: basal, watching a popular cartoon with audio (V-A), and with muted audio track (VwA). For short-range connections, basal records, statistical significant correlations were found for all EEG bands in the left hemisphere, but no significant correlations were found for fast EEG frequencies in the right hemisphere. For the V-A condition, significant correlations were mainly diminished for the left hemisphere; for the right hemisphere, no significant correlations were found for the fast EEG frequency bands. For the VwA condition, significant correlations for the rapid EEG frequencies mainly disappeared for the right hemisphere. For long-range connections, basal records showed similar correlations for both hemispheres. For the right hemisphere, significant correlations incremented to all EEG bands for the V-A condition, but these significant correlations disappeared for the fast EEG frequencies in the VwA condition. It appears that in a resting-state condition, AC is better associated with functional connectivity for short-range connections in the left hemisphere. The V-A experimental condition enriches the AC and FC association for long-range connections in the right hemisphere. This might be related to an effective connectivity improvement due to full video stimulation (visual and auditory). An impaired audiovisual interaction in the right hemisphere might explain why significant correlations disappeared for the fast EEG frequencies in the VwA experimental condition.

  5. Functional Magnetic Resonance Imaging of Rats with Experimental Autoimmune Encephalomyelitis Reveals Brain Cortex Remodeling

    PubMed Central

    Tambalo, Stefano; Peruzzotti-Jametti, Luca; Rigolio, Roberta; Fiorini, Silvia; Bontempi, Pietro; Mallucci, Giulia; Balzarotti, Beatrice; Marmiroli, Paola; Sbarbati, Andrea; Cavaletti, Guido

    2015-01-01

    Cortical reorganization occurring in multiple sclerosis (MS) patients is thought to play a key role in limiting the effect of structural tissue damage. Conversely, its exhaustion may contribute to the irreversible disability that accumulates with disease progression. Several aspects of MS-related cortical reorganization, including the overall functional effect and likely modulation by therapies, still remain to be elucidated. The aim of this work was to assess the extent of functional cortical reorganization and its brain structural/pathological correlates in Dark Agouti rats with experimental autoimmune encephalomyelitis (EAE), a widely accepted preclinical model of chronic MS. Morphological and functional MRI (fMRI) were performed before disease induction and during the relapsing and chronic phases of EAE. During somatosensory stimulation of the right forepaw, fMRI demonstrated that cortical reorganization occurs in both relapsing and chronic phases of EAE with increased activated volume and decreased laterality index versus baseline values. Voxel-based morphometry demonstrated gray matter (GM) atrophy in the cerebral cortex, and both GM and white matter atrophy were assessed by ex vivo pathology of the sensorimotor cortex and corpus callosum. Neuroinflammation persisted in the relapsing and chronic phases, with dendritic spine density in the layer IV sensory neurons inversely correlating with the number of cluster of differentiation 45-positive inflammatory lesions. Our work provides an innovative experimental platform that may be pivotal for the comprehension of key mechanisms responsible for the accumulation of irreversible brain damage and for the development of innovative therapies to reduce disability in EAE/MS. SIGNIFICANCE STATEMENT Since the early 2000s, functional MRI (fMRI) has demonstrated profound modifications in the recruitment of cortical areas during motor, cognitive, and sensory tasks in multiple sclerosis (MS) patients. Experimental autoimmune

  6. The impact of several craniotomies on transcranial motor evoked potential monitoring during neurosurgery.

    PubMed

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

    2016-10-07

    OBJECTIVE Transcranial motor evoked potential (tMEP) monitoring is popular in neurosurgery; however, the accuracy of tMEP can be impaired by craniotomy. Each craniotomy procedure and changes in the CSF levels affects the current spread. The aim of this study was to investigate the influence of several craniotomies on tMEP monitoring by using C3-4 transcranial electrical stimulation (TES). METHODS The authors used the finite element method to visualize the electric field in the brain, which was generated by TES, using realistic 3D head models developed from T1-weighted MR images. Surfaces of 5 layers of the head (brain, CSF, skull, subcutaneous fat, and skin layer) were separated as accurately as possible. The authors created 5 models of the head, as follows: normal head; frontotemporal craniotomy; parietal craniotomy; temporal craniotomy; and occipital craniotomy. The computer simulation was investigated by finite element methods, and clinical recordings of the stimulation threshold level of upper-extremity tMEP (UE-tMEP) during neurosurgery were also studied in 30 patients to validate the simulation study. RESULTS Bone removal during the craniotomy positively affected the generation of the electric field in the motor cortex if the motor cortex was just under the bone at the margin of the craniotomy window. This finding from the authors' simulation study was consistent with clinical reports of frontotemporal craniotomy cases. A major decrease in CSF levels during an operation had a significantly negative impact on the electric field when the motor cortex was exposed to air. The CSF surface level during neurosurgery depends on the body position and location of the craniotomy. The parietal craniotomy and temporal craniotomy were susceptible to the effect of the changing CSF level, based on the simulation study. A marked increase in the threshold following a decrease in CSF was actually recorded in clinical reports of the UE-tMEP threshold from a temporal craniotomy

  7. Acidity of the amidoxime functional group in aqueous solution. A combined experimental and computational study

    SciTech Connect

    Mehio, Nada; Lashely, Mark A.; Nugent, Joseph W.; Tucker, Lyndsay; Correia, Bruna; Do-Thanh, Chi-Linh; Dai, Sheng; Hancock, Robert D.; Bryantsev, Vyacheslav S.

    2015-01-26

    Poly(acrylamidoxime) adsorbents are often invoked in discussions of mining uranium from seawater. It has been demonstrated repeatedly in the literature that the success of these materials is due to the amidoxime functional group. While the amidoxime-uranyl chelation mode has been established, a number of essential binding constants remain unclear. This is largely due to the wide range of conflicting pKa values that have been reported for the amidoxime functional group in the literature. To resolve this existing controversy we investigated the pKa values of the amidoxime functional group using a combination of experimental and computational methods. Experimentally, we used spectroscopic titrations to measure the pKa values of representative amidoximes, acetamidoxime and benzamidoxime. Computationally, we report on the performance of several protocols for predicting the pKa values of aqueous oxoacids. Calculations carried out at the MP2 or M06-2X levels of theory combined with solvent effects calculated using the SMD model provide the best overall performance with a mean absolute error of 0.33 pKa units and 0.35 pKa units, respectively, and a root mean square deviation of 0.46 pKa units and 0.45 pKa units, respectively. Finally, we employ our two best methods to predict the pKa values of promising, uncharacterized amidoxime ligands. Hence, our study provides a convenient means for screening suitable amidoxime monomers for future generations of poly(acrylamidoxime) adsorbents used to mine uranium from seawater.

  8. Acidity of the amidoxime functional group in aqueous solution. A combined experimental and computational study

    DOE PAGES

    Mehio, Nada; Lashely, Mark A.; Nugent, Joseph W.; ...

    2015-01-26

    Poly(acrylamidoxime) adsorbents are often invoked in discussions of mining uranium from seawater. It has been demonstrated repeatedly in the literature that the success of these materials is due to the amidoxime functional group. While the amidoxime-uranyl chelation mode has been established, a number of essential binding constants remain unclear. This is largely due to the wide range of conflicting pKa values that have been reported for the amidoxime functional group in the literature. To resolve this existing controversy we investigated the pKa values of the amidoxime functional group using a combination of experimental and computational methods. Experimentally, we used spectroscopicmore » titrations to measure the pKa values of representative amidoximes, acetamidoxime and benzamidoxime. Computationally, we report on the performance of several protocols for predicting the pKa values of aqueous oxoacids. Calculations carried out at the MP2 or M06-2X levels of theory combined with solvent effects calculated using the SMD model provide the best overall performance with a mean absolute error of 0.33 pKa units and 0.35 pKa units, respectively, and a root mean square deviation of 0.46 pKa units and 0.45 pKa units, respectively. Finally, we employ our two best methods to predict the pKa values of promising, uncharacterized amidoxime ligands. Hence, our study provides a convenient means for screening suitable amidoxime monomers for future generations of poly(acrylamidoxime) adsorbents used to mine uranium from seawater.« less

  9. Pediatric neurosurgery telemedicine clinics: a model to provide care to geographically underserved areas of the United States and its territories.

    PubMed

    James, Hector E

    2016-12-01

    OBJECTIVE The author describes the creation, structuring, and development of a pediatric neurosurgery telemedicine clinic (TMC) to provide telehealth across geographical, time, social, and cultural barriers. METHODS In July 2009 the University of Florida (UF) Division of Pediatric Neurosurgery received a request from the Southeast Georgia Health District (Area 9-2) to provide a TMC to meet regional needs. The Children's Medical Services (CMS) of the State of Georgia installed telemedicine equipment and site-to-site connectivity. Audiovisual connectivity was performed in the UF Pediatric Neurosurgery office, maintaining privacy and HIPAA (Health Insurance Portability and Accountability Act) requirements. Administrative steps were taken with documentation of onsite training of the secretarial and nursing personnel of the CMS clinic. Patient preregistration and documentation were performed as required by the UF College of Medicine-Jacksonville. Monthly clinics are held with the CMS nursing personnel presenting the pertinent clinical history and findings to the pediatric neurosurgeon in the presence of the patient/parents. Physical findings and diagnostic studies are discussed, and management decisions are made. RESULTS The first TMC was held in August 2011. A total of 40 TMC sessions have been held through January 2016, with a total of 43 patients seen: 13 patients once; 13 patients twice; 8 patients for 3 visits; 2 for 4 visits; 2 for 6 visits; 2 for 5 visits; 2 for 7 visits; and 1 patient has been seen 8 times. CONCLUSIONS Pediatric patients in areas of the continental US and its territories with limited access to pediatric neurosurgery services could benefit from this model, if other pediatric neurosurgery centers provide telehealth services.

  10. Investment in Constitutive Immune Function by North American Elk Experimentally Maintained at Two Different Population Densities

    PubMed Central

    Downs, Cynthia J.; Stewart, Kelley M.; Dick, Brian L.

    2015-01-01

    Natural selection favors individuals that respond with effective and appropriate immune responses to macro or microparasites. Animals living in populations close to ecological carrying capacity experience increased intraspecific competition, and as a result are often in poor nutritional condition. Nutritional condition, in turn, affects the amount of endogenous resources that are available for investment in immune function. Our objective was to understand the relationship between immune function and density dependence mediated by trade-offs between immune function, nutritional condition, and reproduction. To determine how immune function relates to density-dependent processes, we quantified bacteria killing ability, hemolytic-complement activity, and nutritional condition of North American elk (Cervus elaphus) from populations maintained at experimentally high- and low-population densities. When compared with elk from the low-density population, those from the high-density population had higher bacteria killing ability and hemolytic-complement activity despite their lower nutritional condition. Similarly, when compared with adults, yearlings had higher bacteria killing ability, higher hemolytic-complement activity, and lower nutritional condition. Pregnancy status and lactational status did not change either measure of constitutive immunity. Density-dependent processes affected both nutritional condition and investment in constitutive immune function. Although the mechanism for how density affects immunity is ambiguous, we hypothesize two possibilities: (i) individuals in higher population densities and in poorer nutritional condition invested more into constitutive immune defenses, or (ii) had higher parasite loads causing higher induced immune responses. Those explanations are not mutually exclusive, and might be synergistic, but overall our results provide stronger support for the hypothesis that animals in poorer nutritional condition invest more in

  11. Investment in constitutive immune function by North American elk experimentally maintained at two different population densities.

    PubMed

    Downs, Cynthia J; Stewart, Kelley M; Dick, Brian L

    2015-01-01

    Natural selection favors individuals that respond with effective and appropriate immune responses to macro or microparasites. Animals living in populations close to ecological carrying capacity experience increased intraspecific competition, and as a result are often in poor nutritional condition. Nutritional condition, in turn, affects the amount of endogenous resources that are available for investment in immune function. Our objective was to understand the relationship between immune function and density dependence mediated by trade-offs between immune function, nutritional condition, and reproduction. To determine how immune function relates to density-dependent processes, we quantified bacteria killing ability, hemolytic-complement activity, and nutritional condition of North American elk (Cervus elaphus) from populations maintained at experimentally high- and low-population densities. When compared with elk from the low-density population, those from the high-density population had higher bacteria killing ability and hemolytic-complement activity despite their lower nutritional condition. Similarly, when compared with adults, yearlings had higher bacteria killing ability, higher hemolytic-complement activity, and lower nutritional condition. Pregnancy status and lactational status did not change either measure of constitutive immunity. Density-dependent processes affected both nutritional condition and investment in constitutive immune function. Although the mechanism for how density affects immunity is ambiguous, we hypothesize two possibilities: (i) individuals in higher population densities and in poorer nutritional condition invested more into constitutive immune defenses, or (ii) had higher parasite loads causing higher induced immune responses. Those explanations are not mutually exclusive, and might be synergistic, but overall our results provide stronger support for the hypothesis that animals in poorer nutritional condition invest more in

  12. An Experimental Investigation of the Functional Hypothesis and Evolutionary Advantage of Stone-Tipped Spears

    PubMed Central

    Wilkins, Jayne; Schoville, Benjamin J.; Brown, Kyle S.

    2014-01-01

    Stone-tipped weapons were a significant innovation for Middle Pleistocene hominins. Hafted hunting technology represents the development of new cognitive and social learning mechanisms within the genus Homo, and may have provided a foraging advantage over simpler forms of hunting technology, such as a sharpened wooden spear. However, the nature of this foraging advantage has not been confirmed. Experimental studies and ethnographic reports provide conflicting results regarding the relative importance of the functional, economic, and social roles of hafted hunting technology. The controlled experiment reported here was designed to test the functional hypothesis for stone-tipped weapons using spears and ballistics gelatin. It differs from previous investigations of this type because it includes a quantitative analysis of wound track profiles and focuses specifically on hand-delivered spear technology. Our results do not support the hypothesis that tipped spears penetrate deeper than untipped spears. However, tipped spears create a significantly larger inner wound cavity that widens distally. This inner wound cavity is analogous to the permanent wound cavity in ballistics research, which is considered the key variable affecting the relative ‘stopping power’ or ‘killing power’ of a penetrating weapon. Tipped spears conferred a functional advantage to Middle Pleistocene hominins, potentially affecting the frequency and regularity of hunting success with important implications for human adaptation and life history. PMID:25162397

  13. An experimental investigation of the functional hypothesis and evolutionary advantage of stone-tipped spears.

    PubMed

    Wilkins, Jayne; Schoville, Benjamin J; Brown, Kyle S

    2014-01-01

    Stone-tipped weapons were a significant innovation for Middle Pleistocene hominins. Hafted hunting technology represents the development of new cognitive and social learning mechanisms within the genus Homo, and may have provided a foraging advantage over simpler forms of hunting technology, such as a sharpened wooden spear. However, the nature of this foraging advantage has not been confirmed. Experimental studies and ethnographic reports provide conflicting results regarding the relative importance of the functional, economic, and social roles of hafted hunting technology. The controlled experiment reported here was designed to test the functional hypothesis for stone-tipped weapons using spears and ballistics gelatin. It differs from previous investigations of this type because it includes a quantitative analysis of wound track profiles and focuses specifically on hand-delivered spear technology. Our results do not support the hypothesis that tipped spears penetrate deeper than untipped spears. However, tipped spears create a significantly larger inner wound cavity that widens distally. This inner wound cavity is analogous to the permanent wound cavity in ballistics research, which is considered the key variable affecting the relative 'stopping power' or 'killing power' of a penetrating weapon. Tipped spears conferred a functional advantage to Middle Pleistocene hominins, potentially affecting the frequency and regularity of hunting success with important implications for human adaptation and life history.

  14. Transition from wind pollination to insect pollination in sedges: experimental evidence and functional traits.

    PubMed

    Wragg, Peter D; Johnson, Steven D

    2011-09-01

    Transitions from wind pollination to insect pollination were pivotal to the radiation of land plants, yet only a handful are known and the trait shifts required are poorly understood. We tested the hypothesis that a transition to insect pollination took place in the ancestrally wind-pollinated sedges (Cyperaceae) and that floral traits modified during this transition have functional significance. We paired putatively insect-pollinated Cyperus obtusiflorus and Cyperus sphaerocephalus with related, co-flowering, co-occurring wind-pollinated species, and compared pairs in terms of pollination mode and functional roles of floral traits. Experimentally excluding insects reduced seed set by 56-89% in putatively insect-pollinated species but not in intermingled wind-pollinated species. The pollen of putatively insect-pollinated species was less motile in a wind tunnel than that of wind-pollinated species. Bees, beetles and flies preferred inflorescences, and color-matched white or yellow models, of putatively insect-pollinated species over inflorescences, or color-matched brown models, of wind-pollinated species. Floral scents of putatively insect-pollinated species were chemically consistent with those of other insect-pollinated plants, and attracted pollinators; wind-pollinated species were unscented. These results show that a transition from wind pollination to insect pollination occurred in sedges and shed new light on the function of traits involved in this important transition.

  15. A novel registration method for image-guided neurosurgery system based on stereo vision.

    PubMed

    An, Yong; Wang, Manning; Song, Zhijian

    2015-01-01

    This study presents a novel spatial registration method of Image-guided neurosurgery system (IGNS) based on stereo-vision. Images of the patient's head are captured by a video camera, which is calibrated and tracked by an optical tracking system. Then, a set of sparse facial data points are reconstructed from them by stereo vision in the patient space. Surface matching method is utilized to register the reconstructed sparse points and the facial surface reconstructed from preoperative images of the patient. Simulation experiments verified the feasibility of the proposed method. The proposed method it is a new low-cost and easy-to-use spatial registration method for IGNS, with good prospects for clinical application.

  16. An Intelligent Robotic Hospital Bed for Safe Transportation of Critical Neurosurgery Patients Along Crowded Hospital Corridors.

    PubMed

    Wang, Chao; Savkin, Andrey V; Clout, Ray; Nguyen, Hung T

    2015-09-01

    We present a novel design of an intelligent robotic hospital bed, named Flexbed, with autonomous navigation ability. The robotic bed is developed for fast and safe transportation of critical neurosurgery patients without changing beds. Flexbed is more efficient and safe during the transportation process comparing to the conventional hospital beds. Flexbed is able to avoid en-route obstacles with an efficient easy-to-implement collision avoidance strategy when an obstacle is nearby and to move towards its destination at maximum speed when there is no threat of collision. We present extensive simulation results of navigation of Flexbed in the crowded hospital corridor environments with moving obstacles. Moreover, results of experiments with Flexbed in the real world scenarios are also presented and discussed.

  17. Severe head injury in children: emergency access to neurosurgery in the United Kingdom

    PubMed Central

    Tasker, R C; Morris, K P; Forsyth, R J; Hawley, C A; Parslow, R C

    2006-01-01

    Objective To determine the scale of acute neurosurgery for severe traumatic brain injury (TBI) in childhood, and whether surgical evacuation for haematoma is achieved within four hours of presentation to an emergency department. Methods A 12 month audit of emergency access to all specialist neurosurgical and intensive care services in the UK. Severe TBI in a child was defined as that necessitating admission to intensive care. Results Of 448 children with severe head injuries, 91 (20.3%) underwent emergency neurosurgery, and 37% of these surgical patients had at least one non‐reactive and dilated pupil. An acute subdural or epidural haematoma was present in 143/448 (31.9%) children, of whom 66 (46.2%) underwent surgery. Children needing surgical evacuation of haematoma were at a median distance of 29 km (interquartile range (IQR) 11.8–45.7) from their neurosurgical centre. One in four children took longer than one hour to reach hospital after injury. Once in an accident and emergency department, 41% took longer than fours hours to arrive at the regional centre. The median interval between time of accident and arrival at the surgical centre was 4.5 hours (IQR 2.23–7.73), and 79% of inter‐hospital transfers were undertaken by the referring hospital rather than the regional centre. In cases where the regional centre undertook the transfer, none were completed within four hours of presentation—the median interval was 6.3 hours (IQR 5.1–8.12). Conclusions The system of care for severely head injured children in the UK does not achieve surgical evacuation of a significant haematoma within four hours. The recommendation to use specialist regional paediatric transfer teams delays rather than expedites the emergency service. PMID:16794092

  18. Paediatric day-case neurosurgery in a resource challenged setting: Pattern and practice

    PubMed Central

    Owojuyigbe, Afolabi Muyiwa; Komolafe, Edward O.; Adenekan, Anthony T.; Dada, Muyiwa A.; Onyia, Chiazor U.; Ogunbameru, Ibironke O.; Owagbemi, Oluwafemi F.; Talabi, Ademola O.; Faponle, Fola A.

    2016-01-01

    Background: It has been generally observed that children achieve better convalescence in the home environment especially if discharged same day after surgery. This is probably due to the fact that children generally tend to feel more at ease in the home environment than in the hospital setting. Only few tertiary health institutions provide routine day-case surgery for paediatric neurosurgical patients in our sub-region. Objective: To review the pattern and practice of paediatric neurosurgical day-cases at our hospital. Patients and Methods: A prospective study of all paediatric day-case neurosurgeries carried out between June 2011 and June 2014. Results: A total of 53 patients (34 males and 19 females) with age ranging from 2 days to 14 years were seen. Majority of the patients (77.4%) presented with congenital lesions, and the most common procedure carried out was spina bifida repair (32%) followed by ventriculoperitoneal shunt insertion (26.4%) for hydrocephalus. Sixty-eight percentage belonged to the American Society of Anesthesiologists physical status class 2, whereas the rest (32%) belonged to class 1. General anaesthesia was employed in 83% of cases. Parenteral paracetamol was used for intra-operative analgesia for most of the patients. Two patients had post-operative nausea and vomiting and were successfully managed. There was no case of emergency re-operation, unplanned admission, cancellation or mortality. Conclusion: Paediatric day-case neurosurgery is feasible in our environment. With careful patient selection and adequate pre-operative preparation, good outcome can be achieved. PMID:27251657

  19. A Patient Registry to Improve Patient Safety: Recording General Neurosurgery Complications

    PubMed Central

    Sarnthein, Johannes; Stieglitz, Lennart; Clavien, Pierre-Alain; Regli, Luca

    2016-01-01

    Background To improve the transparency of the local health care system, treatment cost was recently referenced to disease related groups. Treatment quality must be legally documented in a patient registry, in particular for the highly specialized treatments provided by neurosurgery departments. Methods In 2013 we have installed a patient registry focused on cranial neurosurgery. Surgeries are characterized by indication, treatment, location and other specific neurosurgical parameters. Preoperative state and postoperative outcome are recorded prospectively using neurological and sociological scales. Complications are graded by their severity in a therapy-oriented complication score system (Clavien-Dindo-Grading system, CDG). Results are presented at the monthly clinical staff meeting. Results Data acquisition compatible with the clinic workflow permitted to include all eligible patients into the registry. Until December 2015, we have registered 2880 patients that were treated in 3959 surgeries and 8528 consultations. Since the registry is fully operational (August 2014), we have registered 325 complications on 1341 patient discharge forms (24%). In 64% of these complications, no or only pharmacological treatment was required. At discharge, there was a clear correlation of the severity of the complication and the Karnofsky Performance Status (KPS, ρ = -0.3, slope -6 KPS percentage points per increment of CDG) and the length of stay (ρ = 0.4, slope 1.5 days per increment of CDG). Conclusions While the therapy-oriented complication scores correlate reasonably well with outcome and length of stay, they do not account for new deficits that cannot be treated. Outcome grading and complication severity grading thus serve a complimentary purpose. Overall, the registry serves to streamline and to complete information flow in the clinic, to identify complication rates and trends early for the internal quality monitoring and communication with patients. Conversely, the

  20. Application of underwater shock wave and laser-induced liquid jet to neurosurgery

    NASA Astrophysics Data System (ADS)

    Tominaga, T.; Nakagawa, A.; Hirano, T.; Sato, J.; Kato, K.; Hosseini, S. H. R.; Takayama, K.

    2006-03-01

    Paper deals with applications of underwater shock waves to medicine. A historical development of underwater shock wave generation by using pulsed Ho:YAG laser beam irradiation in water is briefly described and an overview is given regarding potential applications of shock waves to neuro-surgery. The laser beam irradiation in a liquid-filled catheter produces water vapor bubble and shock waves intermittently produces micro-liquid jets in a controlled fashion from the exit of the catheter. Correlations between shock dynamics and bubble dynamics are emphasized. To optimize the jet motion, results of basic parametric studies are briefly presented. The liquid jet discharged from the catheter exit has an impulse high enough to clearly exhibit effectiveness for various medical purposes. In liquid jets we observed reasonably strong shock waves and hence invented a compact shock generator aiming to apply to microsurgery. We applied it to a rat's bone window and developed an effective method of brain protection against shock loading. The insertion of Gore-Tex® sheet is found to attenuate shock waves drastically even for very short stand off distance and its physical mechanism is clarified. The laser-induced liquid jet (LILJ) is successfully applied to soft tissue dissection. Animal experiments were performed and results of histological observations are presented in details. Results of animal experiments revealed that LILJ can sharply dissect soft tissue with a minimum amount of liquid consumption, while blood vessels larger than 0.2 mm in diameter are preserved. Shock waves and LILJ have a potential to be indispensable tools in neuro-surgery.

  1. Integrating risk management data in quality improvement initiatives within an academic neurosurgery department.

    PubMed

    McLaughlin, Nancy; Garrett, Matthew C; Emami, Leila; Foss, Sarah K; Klohn, Johanna L; Martin, Neil A

    2016-01-01

    OBJECT While malpractice litigation has had many negative impacts on health care delivery systems, information extracted from lawsuits could potentially guide toward venues to improve care. The authors present a comprehensive review of lawsuits within a tertiary academic neurosurgical department and report institutional and departmental strategies to mitigate liability by integrating risk management data with quality improvement initiatives. METHODS The Comprehensive Risk Intelligence Tool database was interrogated to extract claims/suits abstracts concerning neurosurgical cases that were closed from January 2008 to December 2012. Variables included demographics of the claimant, type of procedure performed (if any), claim description, insured information, case outcome, clinical summary, contributing factors and subfactors, amount incurred for indemnity and expenses, and independent expert opinion in regard to whether the standard of care was met. RESULTS During the study period, the Department of Neurosurgery received the most lawsuits of all surgical specialties (30 of 172), leading to a total incurred payment of $4,949,867. Of these lawsuits, 21 involved spinal pathologies and 9 cranial pathologies. The largest group of suits was from patients with challenging medical conditions who underwent uneventful surgeries and postoperative courses but filed lawsuits when they did not see the benefits for which they were hoping; 85% of these claims were withdrawn by the plaintiffs. The most commonly cited contributing factors included clinical judgment (20 of 30), technical skill (19 of 30), and communication (6 of 30). CONCLUSIONS While all medical and surgical subspecialties must deal with the issue of malpractice and liability, neurosurgery is most affected both in terms of the number of suits filed as well as monetary amounts awarded. To use the suits as learning tools for the faculty and residents and minimize the associated costs, quality initiatives addressing the

  2. Future directions in 3-dimensional imaging and neurosurgery: stereoscopy and autostereoscopy.

    PubMed

    Christopher, Lauren A; William, Albert; Cohen-Gadol, Aaron A

    2013-01-01

    Recent advances in 3-dimensional (3-D) stereoscopic imaging have enabled 3-D display technologies in the operating room. We find 2 beneficial applications for the inclusion of 3-D imaging in clinical practice. The first is the real-time 3-D display in the surgical theater, which is useful for the neurosurgeon and observers. In surgery, a 3-D display can include a cutting-edge mixed-mode graphic overlay for image-guided surgery. The second application is to improve the training of residents and observers in neurosurgical techniques. This article documents the requirements of both applications for a 3-D system in the operating room and for clinical neurosurgical training, followed by a discussion of the strengths and weaknesses of the current and emerging 3-D display technologies. An important comparison between a new autostereoscopic display without glasses and current stereo display with glasses improves our understanding of the best applications for 3-D in neurosurgery. Today's multiview autostereoscopic display has 3 major benefits: It does not require glasses for viewing; it allows multiple views; and it improves the workflow for image-guided surgery registration and overlay tasks because of its depth-rendering format and tools. Two current limitations of the autostereoscopic display are that resolution is reduced and depth can be perceived as too shallow in some cases. Higher-resolution displays will be available soon, and the algorithms for depth inference from stereo can be improved. The stereoscopic and autostereoscopic systems from microscope cameras to displays were compared by the use of recorded and live content from surgery. To the best of our knowledge, this is the first report of application of autostereoscopy in neurosurgery.

  3. Experimental Energy Levels and Partition Function of the 12C2 Molecule

    NASA Astrophysics Data System (ADS)

    Furtenbacher, Tibor; Szabó, István; Császár, Attila G.; Bernath, Peter F.; Yurchenko, Sergei N.; Tennyson, Jonathan

    2016-06-01

    The carbon dimer, the 12C2 molecule, is ubiquitous in astronomical environments. Experimental-quality rovibronic energy levels are reported for 12C2, based on rovibronic transitions measured for and among its singlet, triplet, and quintet electronic states, reported in 42 publications. The determination utilizes the Measured Active Rotational-Vibrational Energy Levels (MARVEL) technique. The 23,343 transitions measured experimentally and validated within this study determine 5699 rovibronic energy levels, 1325, 4309, and 65 levels for the singlet, triplet, and quintet states investigated, respectively. The MARVEL analysis provides rovibronic energies for six singlet, six triplet, and two quintet electronic states. For example, the lowest measurable energy level of the {{a}}{}3{{{\\Pi }}}{{u}} state, corresponding to the J = 2 total angular momentum quantum number and the F 1 spin-multiplet component, is 603.817(5) cm-1. This well-determined energy difference should facilitate observations of singlet-triplet intercombination lines, which are thought to occur in the interstellar medium and comets. The large number of highly accurate and clearly labeled transitions that can be derived by combining MARVEL energy levels with computed temperature-dependent intensities should help a number of astrophysical observations as well as corresponding laboratory measurements. The experimental rovibronic energy levels, augmented, where needed, with ab initio variational ones based on empirically adjusted and spin-orbit coupled potential energy curves obtained using the Duo code, are used to obtain a highly accurate partition function, and related thermodynamic data, for 12C2 up to 4000 K.

  4. Liquid contact resonance atomic force microscopy via experimental reconstruction of the hydrodynamic function

    SciTech Connect

    Tung, Ryan C. Killgore, Jason P.; Hurley, Donna C.

    2014-06-14

    We present a method to correct for surface-coupled inertial and viscous fluid loading forces in contact resonance (CR) atomic force microscopy (AFM) experiments performed in liquid. Based on analytical hydrodynamic theory, the method relies on experimental measurements of the AFM cantilever's free resonance peaks near the sample surface. The free resonance frequencies and quality factors in both air and liquid allow reconstruction of a continuous hydrodynamic function that can be used to adjust the CR data in liquid. Validation experiments utilizing thermally excited free and in-contact spectra were performed to assess the accuracy of our approach. Results show that the method recovers the air frequency values within approximately 6%. Knowledge of fluid loading forces allows current CR analysis techniques formulated for use in air and vacuum environments to be applied to liquid environments. Our technique greatly extends the range of measurement environments available to CR-AFM.

  5. Experimental verification of modified synthetic discriminant function filters for rotation invariance

    NASA Technical Reports Server (NTRS)

    Reid, Max B.; Ma, Paul W.; Downie, John D.; Ochoa, Ellen

    1990-01-01

    Experimental results are presented which demonstrate that effective binary synthetic discriminant functions (SDFs) can be constructed if the binary nature of the filter modulation is included in SDF synthesis. It is also shown that the iterative procedure needed to produce the SDF is well performed on the optical correlator, as opposed to off-line computation. Binary SDF filters have been demonstrated which produce approximately equal correlation peaks over in-plane rotation ranges up to 75 deg and out-of-plane rotation ranges up to 60 deg. This technique, combined with the translational position invariance of optical filters, allows a single filter to track a Shuttle Orbiter as it moves along a curved path across the input field.

  6. An experimental approach to study the function of mitochondria in cardiomyopathy

    PubMed Central

    Chung, Youn Wook; Kang, Seok-Min

    2015-01-01

    Cardiomyopathy is an inherited or acquired disease of the myocardium, which can result in severe ventricular dysfunction. Mitochondrial dysfunction is involved in the pathological process of cardiomyopathy. Many dysfunctions in cardiac mitochondria are consequences of mutations in nuclear or mitochondrial DNA followed by alterations in transcriptional regulation, mitochondrial protein function, and mitochondrial dynamics and energetics, presenting with associated multisystem mitochondrial disorders. To ensure correct diagnosis and optimal management of mitochondrial dysfunction in cardiomyopathy caused by multiple pathogenesis, multidisciplinary approaches are required, and to integrate between clinical and basic sciences, ideal translational models are needed. In this review, we will focus on experimental models to provide insights into basic mitochondrial physiology and detailed underlying mechanisms of cardiomyopathy and current mitochondria-targeted therapies for cardiomyopathy. [BMB Reports 2015; 48(10): 541-548] PMID:26198095

  7. Reconstruction of Kelvin probe force microscopy image with experimentally calibrated point spread function

    NASA Astrophysics Data System (ADS)

    Lan, Fei; Jiang, Minlin; Tao, Quan; Wei, Fanan; Li, Guangyong

    2017-03-01

    A Kelvin probe force microscopy (KPFM) image is sometimes difficult to interpret because it is a blurred representation of the true surface potential (SP) distribution of the materials under test. The reason for the blurring is that KPFM relies on the detection of electrostatic force, which is a long-range force compared to other surface forces. Usually, KPFM imaging model is described as the convolution of the true SP distribution of the sample with an intrinsic point spread function (PSF) of the measurement system. To restore the true SP signals from the blurred ones, the intrinsic PSF of the system is needed. In this work, we present a way to experimentally calibrate the PSF of the KPFM system. Taking the actual probe shape and experimental parameters into consideration, this calibration method leads to a more accurate PSF than the ones obtained from simulations. Moreover, a nonlinear reconstruction algorithm based on total variation (TV) regularization is applied to KPFM measurement to reverse the blurring caused by PSF during KPFM imaging process; as a result, noises are reduced and the fidelity of SP signals is improved.

  8. What happens inside a fuel cell? Developing an experimental functional map of fuel cell performance.

    PubMed

    Brett, Daniel J L; Kucernak, Anthony R; Aguiar, Patricia; Atkins, Stephen C; Brandon, Nigel P; Clague, Ralph; Cohen, Lesley F; Hinds, Gareth; Kalyvas, Christos; Offer, Gregory J; Ladewig, Bradley; Maher, Robert; Marquis, Andrew; Shearing, Paul; Vasileiadis, Nikos; Vesovic, Velisa

    2010-09-10

    Fuel cell performance is determined by the complex interplay of mass transport, energy transfer and electrochemical processes. The convolution of these processes leads to spatial heterogeneity in the way that fuel cells perform, particularly due to reactant consumption, water management and the design of fluid-flow plates. It is therefore unlikely that any bulk measurement made on a fuel cell will accurately represent performance at all parts of the cell. The ability to make spatially resolved measurements in a fuel cell provides one of the most useful ways in which to monitor and optimise performance. This Minireview explores a range of in situ techniques being used to study fuel cells and describes the use of novel experimental techniques that the authors have used to develop an 'experimental functional map' of fuel cell performance. These techniques include the mapping of current density, electrochemical impedance, electrolyte conductivity, contact resistance and CO poisoning distribution within working PEFCs, as well as mapping the flow of reactant in gas channels using laser Doppler anemometry (LDA). For the high-temperature solid oxide fuel cell (SOFC), temperature mapping, reference electrode placement and the use of Raman spectroscopy are described along with methods to map the microstructural features of electrodes. The combination of these techniques, applied across a range of fuel cell operating conditions, allows a unique picture of the internal workings of fuel cells to be obtained and have been used to validate both numerical and analytical models.

  9. Kinetic energies to analyze the experimental auger electron spectra by density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Endo, Kazunaka

    2016-02-01

    In the Auger electron spectra (AES) simulations, we define theoretical modified kinetic energies of AES in the density functional theory (DFT) calculations. The modified kinetic energies correspond to two final-state holes at the ground state and at the transition-state in DFT calculations, respectively. This method is applied to simulate Auger electron spectra (AES) of 2nd periodic atom (Li, Be, B, C, N, O, F)-involving substances (LiF, beryllium, boron, graphite, GaN, SiO2, PTFE) by deMon DFT calculations using the model molecules of the unit cell. Experimental KVV (valence band electrons can fill K-shell core holes or be emitted during KVV-type transitions) AES of the (Li, O) atoms in the substances agree considerably well with simulation of AES obtained with the maximum kinetic energies of the atoms, while, for AES of LiF, and PTFE substance, the experimental F KVV AES is almost in accordance with the spectra from the transitionstate kinetic energy calculations.

  10. Experimental Determination of the Electric Dipole Moment Function of the X Pi-2 Hydroxyl Radical

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Goorvitch, D.; Abrams, M. C.; Davis, S. P.; Benidar, A.; Farrenq, R.; Guelachvili, G.; Strawa, Anthony W. (Technical Monitor)

    1995-01-01

    Laboratory infrared emission spectra of X 2piOH obtained with the Solar McMath FTS and the U. Paris (Orsay) FTS are used in an inversion procedure to experimentally determine the electric dipole moment function (EDMF) of the hydroxyl radical. The spectra produced at Kitt Peak show vibrational levels up to v = 10 and rotational lines in the range, -25.5 less than or equal to m less than or equal to 12.5. The following vibrational quantum number ranges were observed: for DELTA v = -1, v prime = 1 - 9, for DELTA v = -2, v prime = 2 - 10, and for DELTA v = - 3, v prime = 6 - 10. The spectra produced at Orsay show DELTA v = -1, with v prime = 1 - 4 and -22.5 less than or equal to m less than or equal to 9.5 as well as DELTA v = 0, with v prime= 1 - 3, and 9.5 less than or equal to m less than or equal to 25.5. The OH rovibrational wavefunctions used in the inversion procedure were calculated using a procedure which reproduces observed rotational constants with a high level of accuracy. Comparisons of our EDMF are made with previous experimental and theoretical work.

  11. [The effect of sulodexide on placental mitochondria function in rats with experimental preeclampsia].

    PubMed

    Popova, T A; Perfilova, V N; Zhakupova, G A; Verovsky, V E; Ostrovskij, O V; Tyurenkov, I N

    2016-07-01

    Substitution of drinking water for 1.8% NaCl in pregnant rats caused a pronounced increase in arterial pressure by 24,3% and urinary protein by 117% to day 21 of pregnancy. State 4 respiration of isolated placental mitochondria in the group of negative control was 3- and 1.5-fold higher with malate/glutamate and succinate as substrates than in placental mitochondria isolated from uncomplicated pregnant animals. This led to a decrease of the respiratory control ratio. These results suggest that development of experimental preeclampsia is accompanied by mitochondrial dysfunction through uncoupling of oxidative phosphorylation. Daily administration of sulodexide to females with experimental preeclampsia (EP) per os at a dose of 30 LE during the whole period of gestation decreased manifestations of the disease as evidenced by a slight increase in blood pressure (by 8,6%) and less pronounces increase in urinary protein (by 58,9%). Sulodexide decreased development of mitochondrial dysfunction in EP rats as shown a decrease of non-stimulated ADP respiration with malate/glutamate and succinate (4.5- and 2.5-fold, respectively) as compared with the negative control group and the corresponding increase in the respiratory control ratio (2.5- and 1.5-fold, respectively). Thus, sulodexide reduces uncoupling of oxidative phosphorylation and enhances the functional activity of mitochondria in EP animals, possibly due to its antioxidant and endotelioprotective effects.

  12. Tiny giants of gene regulation: experimental strategies for microRNA functional studies

    PubMed Central

    Steinkraus, Bruno R.; Toegel, Markus

    2016-01-01

    The discovery over two decades ago of short regulatory microRNAs (miRNAs) has led to the inception of a vast biomedical research field dedicated to understanding these powerful orchestrators of gene expression. Here we aim to provide a comprehensive overview of the methods and techniques underpinning the experimental pipeline employed for exploratory miRNA studies in animals. Some of the greatest challenges in this field have been uncovering the identity of miRNA–target interactions and deciphering their significance with regard to particular physiological or pathological processes. These endeavors relied almost exclusively on the development of powerful research tools encompassing novel bioinformatics pipelines, high‐throughput target identification platforms, and functional target validation methodologies. Thus, in an unparalleled manner, the biomedical technology revolution unceasingly enhanced and refined our ability to dissect miRNA regulatory networks and understand their roles in vivo in the context of cells and organisms. Recurring motifs of target recognition have led to the creation of a large number of multifactorial bioinformatics analysis platforms, which have proved instrumental in guiding experimental miRNA studies. Subsequently, the need for discovery of miRNA–target binding events in vivo drove the emergence of a slew of high‐throughput multiplex strategies, which now provide a viable prospect for elucidating genome‐wide miRNA–target binding maps in a variety of cell types and tissues. Finally, deciphering the functional relevance of miRNA post‐transcriptional gene silencing under physiological conditions, prompted the evolution of a host of technologies enabling systemic manipulation of miRNA homeostasis as well as high‐precision interference with their direct, endogenous targets. WIREs Dev Biol 2016, 5:311–362. doi: 10.1002/wdev.223 For further resources related to this article, please visit the WIREs website. PMID:26950183

  13. Effects of Lactobacillus plantarum on gut barrier function in experimental obstructive jaundice

    PubMed Central

    Zhou, Yu-Kun; Qin, Huan-Long; Zhang, Ming; Shen, Tong-Yi; Chen, Hong-Qi; Ma, Yan-Lei; Chu, Zhao-Xin; Zhang, Peng; Liu, Zhi-Hua

    2012-01-01

    AIM: To investigate the mechanisms of Lactobacillus plantarum (L. plantarum) action on gut barrier in preoperative and postoperative experimental obstructive jaundice in rats. METHODS: Forty rats were randomly divided into groups of sham-operation, bile duct ligation (BDL), BDL + L. plantarum, BDL + internal biliary drainage (IBD), and BDL + IBD + L. plantarum. Ten days after L. plantarum administration, blood and ileal samples were collected from the rats for morphological examination, and intestinal barrier function, liver function, intestinal oxidative stress and protein kinase C (PKC) activity measurement. The distribution and expression of the PKC and tight junction (TJ) proteins, such as occludin, zonula occludens-1, claudin-1, claudin-4, junction adhesion molecule-A and F-actin, were examined by confocal laser scanning microscopy, immunohistochemistry, Western blotting, real-time fluorescent quantitative polymerase chain reaction assay. RESULTS: L. plantarum administration substantially restored gut barrier, decreased enterocyte apoptosis, improved intestinal oxidative stress, promoted the activity and expression of protein kinase (BDL vs BDL + L. plantarum, 0.295 ± 0.007 vs 0.349 ± 0.003, P < 0.05; BDL + IBD vs BDL + IBD + L. plantarum, 0.407 ± 0.046 vs 0.465 ± 0.135, P < 0.05), and particularly enhanced the expression and phosphorylation of TJ proteins in the experimental obstructive jaundice (BDL vs BDL + L. plantarum, 0.266 ± 0.118 vs 0.326 ± 0.009, P < 0.05). The protective effect of L. plantarum was more prominent after internal biliary drainage ( BDL + IBD vs BDL + IBD + L. plantarum, 0.415 ± 0.105 vs 0.494 ± 0.145, P < 0.05). CONCLUSION: L. plantarum can decrease intestinal epithelial cell apoptosis, reduce oxidative stress, and prevent TJ disruption in biliary obstruction by activating the PKC pathway. PMID:22912548

  14. GOsummaries: an R Package for Visual Functional Annotation of Experimental Data.

    PubMed

    Kolde, Raivo; Vilo, Jaak

    2015-01-01

    Functional characterisation of gene lists using Gene Ontology (GO) enrichment analysis is a common approach in computational biology, since many analysis methods end up with a list of genes as a result. Often there can be hundreds of functional terms that are significantly associated with a single list of genes and proper interpretation of such results can be a challenging endeavour. There are methods to visualise and aid the interpretation of these results, but most of them are limited to the results associated with one list of genes. However, in practice the number of gene lists can be considerably higher and common tools are not effective in such situations. We introduce a novel R package, 'GOsummaries' that visualises the GO enrichment results as concise word clouds that can be combined together if the number of gene lists is larger. By also adding the graphs of corresponding raw experimental data, GOsummaries can create informative summary plots for various analyses such as differential expression or clustering. The case studies show that the GOsummaries plots allow rapid functional characterisation of complex sets of gene lists. The GOsummaries approach is particularly effective for Principal Component Analysis (PCA). By adding functional annotation to the principal components, GOsummaries improves  significantly the interpretability of PCA results. The GOsummaries layout for PCA can be effective even in situations where we cannot directly apply the GO analysis. For example, in case of metabolomics or metagenomics data it is possible to show the features with significant associations to the components instead of GO terms.   The GOsummaries package is available under GPL-2 licence at Bioconductor (http://www.bioconductor.org/packages/release/bioc/html/GOsummaries.html).

  15. The relationship between microbial community structure and functional stability, tested experimentally in an upland pasture soil.

    PubMed

    Griffiths, B S; Kuan, H L; Ritz, K; Glover, L A; McCaig, A E; Fenwick, C

    2004-01-01

    Soil collected from an upland pasture was manipulated experimentally in ways shown previously to alter microbial community structure. One set of soil was subjected to chloroform fumigation for 0, 0.5, 2, or 24 h and the other was sterilised by gamma-irradiation and inoculated with a 10(-2), 10(-4), 10(-6), or 10(-8) dilution of a soil suspension prepared from unsterilized soil. Following incubation for 8 months, to allow for the stabilization of microbial biomass and activity, the resulting microbial community structure (determined by PCR-DGGE of bacterial specific amplification products of total soil DNA) was assessed. In addition, the functional stability (defined here as the resistance and resilience of short-term decomposition of plant residues to a transient heat or a persistent copper perturbation) was determined. Changes in the active bacterial population following perturbation (determined by RT-PCR-DGGE of total soil RNA) were also monitored. The manipulations resulted in distinct shifts in microbial community structure as shown by PCR-DGGE profiles, but no significant decreases in the number of bands. These shifts in microbial community structure were associated with a reduction in functional stability. The clear correlation between altered microbial community structure and functional stability observed in this upland pasture soil was not evident when the same protocols were applied to soils in other studies. RT-PCR-DGGE profiles only detected a shift in the active bacterial population following heat, but not copper, perturbation. We conclude that the functional stability of decomposition is related to specific components of the microbial community.

  16. Experimental removal and recovery of subtidal grazers highlights the importance of functional redundancy and temporal context.

    PubMed

    Elahi, Robin; Sebens, Kenneth P

    2013-01-01

    The extent to which different grazers are functionally redundant has strong implications for the maintenance of community structure and function. Grazing by red urchins (Strongylocentrotus franciscanus) on temperate rocky reefs can initiate a switch from invertebrate or macroalgal dominance to an algal crust state, but can also cause increases in the density of molluscan mesograzers. In this study, we tested the hypothesis that red urchins and lined chitons (Tonicella spp.) are redundant in the maintenance of available space, defined as encrusting algae and bare rock. In a factorial field experiment replicated at three sites, we reduced the densities of urchins and chitons on subtidal rock walls for nine months. The effects of grazers were interpreted in the context of natural temporal variation by monitoring the benthic community one year before, during, and after grazer removal. The removal of each grazer in isolation had no effect on the epilithic community, but the removal of both grazers caused an increase in sessile invertebrates. The increase was due primarily to clonal ascidians, which displayed a large (∼75%) relative increase in response to the removal of both grazers. However, the observed non-additive responses to grazer removal were temporary and smaller than seasonal fluctuations. Our data demonstrate that urchins and chitons can be redundant in the maintenance of available space, and highlight the value of drawing conclusions from experimental manipulations within an extended temporal context.

  17. Noble gas adsorption in two-dimensional zeolites: a combined experimental and density functional theory study

    NASA Astrophysics Data System (ADS)

    Wang, Mengen; Zhong, Jianqiang; Boscoboinik, Jorge Anibal; Lu, Deyu

    Zeolites are important industrial catalysts with porous three-dimensional structures. The catalytically active sites are located inside the pores, thus rendering them inaccessible for surface science measurements. We synthesized a two-dimensional (2D) zeolite model system, consisting of an (alumino)silicate bilayer weakly bound to a Ru (0001) surface. The 2D zeolite is suitable for surface science studies; it allows a detailed characterization of the atomic structure of the active site and interrogation of the model system during the catalytic reaction. As an initial step, we use Ar adsorption to obtain a better understanding of the atomic structure of the 2D zeolite. In addition, atomic level studies of rare gas adsorption and separation by zeolite are important for its potential application in nuclear waste sequestration. Experimental studies found that Ar atoms can be trapped inside the 2D-zeolite, raising an interesting question on whether Ar atoms are trapped inside the hexagonal prism nano-cages or at the interface between the (alumino)silicate bilayer and Ru(0001), or both. DFT calculations using van der Waals density functionals were carried out to determine the preferred Ar adsorption sites and the corresponding adsorption energies. This research used resources of the Center for Functional Nanomaterials, which is a U.S. DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE-SC0012704.

  18. Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for pure liquids

    PubMed Central

    Karunaweera, Sadish

    2015-01-01

    Fluctuation solution theory has provided an alternative view of many liquid mixture properties in terms of particle number fluctuations. The particle number fluctuations can also be related to integrals of the corresponding two body distribution functions between molecular pairs in order to provide a more physical picture of solution behavior and molecule affinities. Here, we extend this type of approach to provide expressions for higher order triplet and quadruplet fluctuations, and thereby integrals over the corresponding distribution functions, all of which can be obtained from available experimental thermodynamic data. The fluctuations and integrals are then determined using the International Association for the Properties of Water and Steam Formulation 1995 (IAPWS-95) equation of state for the liquid phase of pure water. The results indicate small, but significant, deviations from a Gaussian distribution for the molecules in this system. The pressure and temperature dependence of the fluctuations and integrals, as well as the limiting behavior as one approaches both the triple point and the critical point, are also examined. PMID:25637990

  19. Endothelin A-receptor blockade in experimental diabetes improves glucose balance and gastrointestinal function.

    PubMed

    Balsiger, Bruno; Rickenbacher, Andreas; Boden, Penelope Jane; Biecker, Erwin; Tsui, Janice; Dashwood, Michael; Reichen, Jürg; Shaw, Sidney George

    2002-08-01

    Secondary complications of diabetes mellitus often involve gastrointestinal dysfunction. In the experimental Goto Kakizaki rat, a model of Type II diabetes, hyperglycaemia and reduced glucose clearance is associated with elevated plasma endothelin (ET)-1 levels and selective decreases in nitric oxide synthase in circular muscle, longitudinal muscle and neuronal elements of the gastrointestinal tract. Functionally, this is accompanied by decreased nitrergic relaxatory responses of jejunal longitudinal muscle to tetrodotoxin-sensitive electrical field stimulation. Long-term treatment with a selective ET A-type receptor antagonist, markedly reduced hyperglycaemia and restored plasma glucose clearance rates towards normal. This was associated with a restoration of N(G)-nitro-L-arginine methyl ester-sensitive relaxatory responses of jejunal longitudinal muscle to electrical field stimulation. The results indicate that beneficial effects of ETA receptor blockade on gastrointestinal function may result from an improvement in insulin sensitivity with concomitant reduction of the severity of hyperglycaemia. ETA receptor blockade may represent a new therapeutic principle for improving glucose tolerance in Type II diabetes and could be beneficial in alleviating or preventing hyperglycaemia-related secondary complications in this condition.

  20. Experimental triplet and quadruplet fluctuation densities and spatial distribution function integrals for pure liquids

    SciTech Connect

    Ploetz, Elizabeth A.; Karunaweera, Sadish; Smith, Paul E.

    2015-01-28

    Fluctuation solution theory has provided an alternative view of many liquid mixture properties in terms of particle number fluctuations. The particle number fluctuations can also be related to integrals of the corresponding two body distribution functions between molecular pairs in order to provide a more physical picture of solution behavior and molecule affinities. Here, we extend this type of approach to provide expressions for higher order triplet and quadruplet fluctuations, and thereby integrals over the corresponding distribution functions, all of which can be obtained from available experimental thermodynamic data. The fluctuations and integrals are then determined using the International Association for the Properties of Water and Steam Formulation 1995 (IAPWS-95) equation of state for the liquid phase of pure water. The results indicate small, but significant, deviations from a Gaussian distribution for the molecules in this system. The pressure and temperature dependence of the fluctuations and integrals, as well as the limiting behavior as one approaches both the triple point and the critical point, are also examined.

  1. Tetracycline antibiotics impair mitochondrial function and its experimental use confounds research.

    PubMed

    Chatzispyrou, Iliana A; Held, Ntsiki M; Mouchiroud, Laurent; Auwerx, Johan; Houtkooper, Riekelt H

    2015-11-01

    Tetracyclines, a class of antibiotics that target bacterial translation, are commonly used in research for inducible gene expression using Tet-ON/Tet-OFF systems. However, such tetracycline-inducible systems carry a risk. Given that mitochondria have a "bacterial" ancestry, these antibiotics also target mitochondrial translation and impair mitochondrial function. Indeed, treatment with doxycycline-a tetracycline derivative-disturbs mitochondrial proteostasis and metabolic activity, and induces widespread gene-expression changes. Together, this affects physiology in well-established model systems ranging from cultured cells to simple organisms and to mice and plants. These changes are observed with doxycycline doses that are widely used to regulate gene expression. In light of these findings, and bearing in mind the conserved role of mitochondria in metabolism and whole organism homeostasis, we caution against the use of tetracyclines in experimental approaches. The use of newly developed tetracycline-based systems that are more sensitive could be an alternative; however, even if no overt mitochondrial toxicity is detected, widespread changes in gene expression may sensitize cells to the intended tetracycline-controlled loss or gain of function, thereby introducing a "two-hit model." This is highly relevant for cancer research, as mitochondrial metabolism holds a central position in the reallocation of nutrients for biomass production known as the Warburg effect.

  2. Effect of melatonin on the functional recovery from experimental traumatic compression of the spinal cord

    PubMed Central

    Schiaveto-de-Souza, A.; da-Silva, C.A.; Defino, H.L.A.; Bel, E.A.Del

    2013-01-01

    Spinal cord injury is an extremely severe condition with no available effective therapies. We examined the effect of melatonin on traumatic compression of the spinal cord. Sixty male adult Wistar rats were divided into three groups: sham-operated animals and animals with 35 and 50% spinal cord compression with a polycarbonate rod spacer. Each group was divided into two subgroups, each receiving an injection of vehicle or melatonin (2.5 mg/kg, intraperitoneal) 5 min prior to and 1, 2, 3, and 4 h after injury. Functional recovery was monitored weekly by the open-field test, the Basso, Beattie and Bresnahan locomotor scale and the inclined plane test. Histological changes of the spinal cord were examined 35 days after injury. Motor scores were progressively lower as spacer size increased according to the motor scale and inclined plane test evaluation at all times of assessment. The results of the two tests were correlated. The open-field test presented similar results with a less pronounced difference between the 35 and 50% compression groups. The injured groups presented functional recovery that was more evident in the first and second weeks. Animals receiving melatonin treatment presented more pronounced functional recovery than vehicle-treated animals as measured by the motor scale or inclined plane. NADPH-d histochemistry revealed integrity of the spinal cord thoracic segment in sham-operated animals and confirmed the severity of the lesion after spinal cord narrowing. The results obtained after experimental compression of the spinal cord support the hypothesis that melatonin may be considered for use in clinical practice because of its protective effect on the secondary wave of neuronal death following the primary wave after spinal cord injury. PMID:23579633

  3. Pixel response function experimental techniques and analysis of active pixel sensor star cameras

    NASA Astrophysics Data System (ADS)

    Fumo, Patrick; Waldron, Erik; Laine, Juha-Pekka; Evans, Gary

    2015-04-01

    The pixel response function (PRF) of a pixel within a focal plane is defined as the pixel intensity with respect to the position of a point source within the pixel. One of its main applications is in the field of astrometry, which is a branch of astronomy that deals with positioning data of a celestial body for tracking movement or adjusting the attitude of a spacecraft. Complementary metal oxide semiconductor (CMOS) image sensors generally offer better radiation tolerance to protons and heavy ions than CCDs making them ideal candidates for space applications aboard satellites, but like all image sensors they are limited by their spatial frequency response, better known as the modulation transfer function. Having a well-calibrated PRF allows us to eliminate some of the uncertainty in the spatial response of the system providing better resolution and a more accurate centroid estimation. This paper describes the experimental setup for determining the PRF of a CMOS image sensor and analyzes the effect on the oversampled point spread function (PSF) of an image intensifier, as well as the effects due to the wavelength of light used as a point source. It was found that using electron bombarded active pixel sensor (EBAPS) intensification technology had a significant impact on the PRF of the camera being tested as a result of an increase in the amount of carrier diffusion between collection sites generated by the intensification process. Taking the full width at half maximum (FWHM) of the resulting data, it was found that the intensified version of a CMOS camera exhibited a PSF roughly 16.42% larger than its nonintensified counterpart.

  4. Dose-dependent functionality and toxicity of green tea polyphenols in experimental rodents.

    PubMed

    Murakami, Akira

    2014-09-01

    A large number of physiologically functional foods are comprised of plant polyphenols. Their antioxidative activities have been intensively studied for a long period and proposed to be one of the major mechanisms of action accounting for their health promotional and disease preventive effects. Green tea polyphenols (GTPs) are considered to possess marked anti-oxidative properties and versatile beneficial functions, including anti-inflammation and cancer prevention. On the other hand, some investigators, including us, have uncovered their toxicity at high doses presumably due to pro-oxidative properties. For instance, both experimental animal studies and epidemiological surveys have demonstrated that GTPs may cause hepatotoxicity. We also recently showed that diets containing high doses (0.5-1%) of a GTP deteriorated dextran sodium sulfate (DSS)-induced intestinal inflammation and carcinogenesis. In addition, colitis mode mice fed a 1% GTP exhibited symptoms of nephrotoxicity, as indicated by marked elevation of serum creatinine level. This diet also increased thiobarbituric acid-reactive substances, a reliable marker of oxidative damage, in both kidneys and livers even in normal mice, while the expression levels of antioxidant enzymes and heat shock proteins (HSPs) were diminished in colitis and normal mice. Intriguingly, GTPs at 0.01% and 0.1% showed hepato-protective activities, i.e., they significantly suppressed DSS-increased serum aspartate aminotransferase and alanine aminotransferase levels. Moreover, those diets remarkably restored DSS-down-regulated expressions of heme oxygenase-1 and HSP70 in livers and kidneys. Taken together, while low and medium doses of GTPs are beneficial in colitis model mice, unwanted side-effects occasionally emerge with high doses. This dose-dependent functionality and toxicity of GTPs are in accordance with the concept of hormesis, in which mild, but not severe, stress activates defense systems for adaptation and survival.

  5. Prokaryotic Chaperonins as Experimental Models for Elucidating Structure-Function Abnormalities of Human Pathogenic Mutant Counterparts

    PubMed Central

    Conway de Macario, Everly; Robb, Frank T.; Macario, Alberto J. L.

    2017-01-01

    All archaea have a chaperonin of Group II (thermosome) in their cytoplasm and some have also a chaperonin of Group I (GroEL; Cpn60; Hsp60). Conversely, all bacteria have GroEL, some in various copies, but only a few have, in addition, a chaperonin (tentatively designated Group III chaperonin) very similar to that occurring in all archaea, i.e., the thermosome subunit, and in the cytosol of eukaryotic cells, named CCT. Thus, nature offers a range of prokaryotic organisms that are potentially useful as experimental models to study the human CCT and its abnormalities. This is important because many diseases, the chaperonopathies, have been identified in which abnormal chaperones, including mutant CCT, are determinant etiologic-pathogenic factors and, therefore, research is needed to elucidate their pathologic features at the molecular level. Such research should lead to the clarification of the molecular mechanisms underlying the pathologic lesions observed in the tissues and organs of patients with chaperonopathies. Information on these key issues is necessary to make progress in diagnosis and treatment. Some of the archaeal organisms as well as some of the bacterial models suitable for studying molecular aspects pertinent to human mutant chaperones are discussed here, focusing on CCT. Results obtained with the archaeon Pyrococcus furiosus model to investigate the impact of a pathogenic CCT5 mutation on molecular properties and chaperoning functions are reviewed. The pathogenic mutation examined weakens the ability of the chaperonin subunit to form stable hexadecamers and as a consequence, the chaperoning functions of the complex are impaired. The future prospect is to find means for stabilizing the hexadecamer, which should lead to a recovering of chaperone function and the improving of lesions and clinical condition. PMID:28119916

  6. Effect of melatonin on the functional recovery from experimental traumatic compression of the spinal cord.

    PubMed

    Schiaveto-de-Souza, A; da-Silva, C A; Defino, H L A; Del Bel, E A

    2013-04-01

    Spinal cord injury is an extremely severe condition with no available effective therapies. We examined the effect of melatonin on traumatic compression of the spinal cord. Sixty male adult Wistar rats were divided into three groups: sham-operated animals and animals with 35 and 50% spinal cord compression with a polycarbonate rod spacer. Each group was divided into two subgroups, each receiving an injection of vehicle or melatonin (2.5 mg/kg, intraperitoneal) 5 min prior to and 1, 2, 3, and 4 h after injury. Functional recovery was monitored weekly by the open-field test, the Basso, Beattie and Bresnahan locomotor scale and the inclined plane test. Histological changes of the spinal cord were examined 35 days after injury. Motor scores were progressively lower as spacer size increased according to the motor scale and inclined plane test evaluation at all times of assessment. The results of the two tests were correlated. The open-field test presented similar results with a less pronounced difference between the 35 and 50% compression groups. The injured groups presented functional recovery that was more evident in the first and second weeks. Animals receiving melatonin treatment presented more pronounced functional recovery than vehicle-treated animals as measured by the motor scale or inclined plane. NADPH-d histochemistry revealed integrity of the spinal cord thoracic segment in sham-operated animals and confirmed the severity of the lesion after spinal cord narrowing. The results obtained after experimental compression of the spinal cord support the hypothesis that melatonin may be considered for use in clinical practice because of its protective effect on the secondary wave of neuronal death following the primary wave after spinal cord injury.

  7. Effects on symptoms and lung function in humans experimentally exposed to diesel exhaust.

    PubMed Central

    Rudell, B; Ledin, M C; Hammarström, U; Stjernberg, N; Lundbäck, B; Sandström, T

    1996-01-01

    OBJECTIVES: Diesel exhaust is a common air pollutant made up of several gases, hydrocarbons, and particles. An experimental study was carried out which was designed to evaluate if a particle trap on the tail pipe of an idling diesel engine would reduce effects on symptoms and lung function caused by the diesel exhaust, compared with exposure to unfiltered exhaust. METHODS: Twelve healthy non-smoking volunteers (aged 20-37) were investigated in an exposure chamber for one hour during light work on a bicycle ergometer at 75 W. Each subject underwent three separate double blind exposures in a randomised sequence: to air and to diesel exhaust with the particle trap at the tail pipe and to unfiltered diesel exhaust. Symptoms were recorded according to the Borg scale before, every 10 minutes during, and 30 minutes after the exposure. Lung function was measured with a computerised whole body plethysmograph. RESULTS: The ceramic wall flow particle trap reduced the number of particles by 46%, whereas other compounds were relatively constant. It was shown that the most prominent symptoms during exposure to diesel exhaust were irritation of the eyes and nose and an unpleasant smell increasing during exposure. Both airway resistance (R(aw)) and specific airway resistance (SR(aw)) increased significantly during the exposures to diesel exhaust. Despite the 46% reduction in particle numbers by the trap effects on symptoms and lung function were not significantly attenuated. CONCLUSION: Exposure to diesel exhaust caused symptoms and bronchoconstriction which were not significantly reduced by a particle trap. PMID:8943829

  8. Lingo-1 inhibited by RNA interference promotes functional recovery of experimental autoimmune encephalomyelitis.

    PubMed

    Wang, Chun-Juan; Qu, Chuan-Qiang; Zhang, Jie; Fu, Pei-Cai; Guo, Shou-Gang; Tang, Rong-Hua

    2014-12-01

    Lingo-1 is a negative regulator of myelination. Repairment of demyelinating diseases, such as multiple sclerosis (MS)/experimental autoimmune encephalomyelitis (EAE), requires activation of the myelination program. In this study, we observed the effect of RNA interference on Lingo-1 expression, and the impact of Lingo-1 suppression on functional recovery and myelination/remyelination in EAE mice. Lentiviral vectors encoding Lingo-1 short hairpin RNA (LV/Lingo-1-shRNA) were constructed to inhibit Lingo-1 expression. LV/Lingo-1-shRNA of different titers were transferred into myelin oligodendrocyte glycoprotein-induced EAE mice by intracerebroventricular (ICV) injection. Meanwhile, lentiviral vectors carrying nonsense gene sequence (LVCON053) were used as negative control. The Lingo-1 expression was detected and locomotor function was evaluated at different time points (on days 1,3,7,14,21, and 30 after ICV injection). Myelination was investigated by luxol fast blue (LFB) staining.LV/Lingo-1-shRNA administration via ICV injection could efficiently down-regulate the Lingo-1 mRNA and protein expression in EAE mice on days 7,14,21, and 30 (P < 0.01), especially in the 5 × 10(8) TU/mL and 5 × 10(9) TU/mL LV/Lingo-1-shRNA groups. The locomotor function score in the LV/Lingo-1-shRNA treated groups were significantly lower than the untreated or LVCON053 group from day 7 on. The 5 × 10(8) TU/mL LV/Lingo-1-shRNA group achieved the best functional improvement (0.87 ± 0.11 vs. 3.05 ± 0.13, P < 0.001). Enhanced myelination/remyelination was observed in the 5 × 10(7) , 5 × 10(8) , 5 × 10(9) TU/mL LV/Lingo-1-shRNA groups by LFB staining (P < 0.05, P < 0.01, and P < 0.05).The data showed that administering LV/Lingo-1-shRNA by ICV injection could efficiently knockdown Lingo-1 expression in vivo, improve functional recovery and enhance myelination/remyelination. Antagonism of Lingo-1 by RNA interference is, therefore, a promising approach for the

  9. Intrinsic functional connectivity of insular cortex and symptoms of sickness during acute experimental inflammation.

    PubMed

    Lekander, Mats; Karshikoff, Bianka; Johansson, Emilia; Soop, Anne; Fransson, Peter; Lundström, Johan N; Andreasson, Anna; Ingvar, Martin; Petrovic, Predrag; Axelsson, John; Nilsonne, Gustav

    2016-08-01

    Task-based fMRI has been used to study the effects of experimental inflammation on the human brain, but it remains unknown whether intrinsic connectivity in the brain at rest changes during a sickness response. Here, we investigated the effect of experimental inflammation on connectivity between areas relevant for monitoring of bodily states, motivation, and subjective symptoms of sickness. In a double-blind randomized controlled experiment, 52 healthy volunteers were injected with 0.6ng/kg LPS (lipopolysaccharide) or placebo, and participated in a resting state fMRI experiment after approximately 2h 45min. Resting state fMRI data were available from 48 participants, of which 28 received LPS and 20 received placebo. Bilateral anterior and bilateral posterior insula sections were used as seed regions and connectivity with bilateral orbitofrontal and cingulate (anterior and middle) cortices was investigated. Back pain, headache and global sickness increased significantly after as compared to before LPS, while a non-significant trend was shown for increased nausea. Compared to placebo, LPS was followed by increased connectivity between left anterior insula and left midcingulate cortex. This connectivity was significantly correlated to increase in back pain after LPS and tended to be related to increased global sickness, but was not related to increased headache or nausea. LPS did not affect the connectivity from other insular seeds. In conclusion, the finding of increased functional connectivity between left anterior insula and middle cingulate cortex suggests a potential neurophysiological mechanism that can be further tested to understand the subjective feeling of malaise and discomfort during a sickness response.

  10. Experimental implementation of the Deutsch-Jozsa algorithm for three-qubit functions using pure coherent molecular superpositions

    SciTech Connect

    Vala, Jiri; Kosloff, Ronnie; Amitay, Zohar; Zhang Bo; Leone, Stephen R.

    2002-12-01

    The Deutsch-Jozsa algorithm is experimentally demonstrated for three-qubit functions using pure coherent superpositions of Li{sub 2} rovibrational eigenstates. The function's character, either constant or balanced, is evaluated by first imprinting the function, using a phase-shaped femtosecond pulse, on a coherent superposition of the molecular states, and then projecting the superposition onto an ionic final state, using a second femtosecond pulse at a specific time delay.

  11. Experimental determination of the 1 Sigma(+) state electric dipole moment function of carbon monoxide up to a large internuclear separation

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Farrenq, R.; Guelachvili, G.; Rossetti, C.; Urban, W.

    1984-01-01

    Experimental intensity information is combined with numerically obtained vibrational wave functions in a nonlinear least-squares fitting procedure to obtain the ground electronic state electric dipole moment function of carbon monoxide valid in the range of nuclear oscillation (0.87-1.91 A) of about the V = 38th vibrational level. Vibrational transition matrix elements are computed from this function for Delta V = 1, 2, 3 with V not more than 38.

  12. Modeling the thermal effect of the bipolar electrocautery for neurosurgery simulation.

    PubMed

    Delorme, Sébastien; Cabral, Anne; Ayres, Fábio; Jiang, Di

    2011-01-01

    Real-time surgical simulation requires computationally-fast models describing the interaction between surgical instrument and tissues. In this study, a model for predicting the temperature distribution in brain tissue when using a bipolar electrocautery is proposed and validated against experimental in vitro animal data. Joule heat generation and heat conduction in the tissue are considered. The agreement between simulated temperature distributions and experimental data could be improved by modeling the output power as a function of electrical resistance between the electrodes, and by considering the heat exchange with surrounding air and bipolar tips.

  13. Review of the potential of optical technologies for cancer diagnosis in neurosurgery: a step toward intraoperative neurophotonics.

    PubMed

    Vasefi, Fartash; MacKinnon, Nicholas; Farkas, Daniel L; Kateb, Babak

    2017-01-01

    Advances in image-guided therapy enable physicians to obtain real-time information on neurological disorders such as brain tumors to improve resection accuracy. Image guidance data include the location, size, shape, type, and extent of tumors. Recent technological advances in neurophotonic engineering have enabled the development of techniques for minimally invasive neurosurgery. Incorporation of these methods in intraoperative imaging decreases surgical procedure time and allows neurosurgeons to find remaining or hidden tumor or epileptic lesions. This facilitates more complete resection and improved topology information for postsurgical therapy (i.e., radiation). We review the clinical application of recent advances in neurophotonic technologies including Raman spectroscopy, thermal imaging, optical coherence tomography, and fluorescence spectroscopy, highlighting the importance of these technologies in live intraoperative tissue mapping during neurosurgery. While these technologies need further validation in larger clinical trials, they show remarkable promise in their ability to help surgeons to better visualize the areas of abnormality and enable safe and successful removal of malignancies.

  14. Effect of Angiotensin(1-7) on Heart Function in an Experimental Rat Model of Obesity

    PubMed Central

    Blanke, Katja; Schlegel, Franziska; Raasch, Walter; Bader, Michael; Dähnert, Ingo; Dhein, Stefan; Salameh, Aida

    2015-01-01

    Aim: Obesity is a risk factor for the development of cardiovascular diseases. Recently it was shown that overexpression of the Mas-receptor antagonist angiotensin(1-7) could prevent from diet-induced obesity. However, it remained unclear whether diet-induced obesity and angiotensin(1-7) overexpression might also have effects on the cardiovascular system in these rats. Methods:Twenty three male Sprague Dawley rats were fed with standard chow (SD+chow, n = 5) or a cafeteria diet (SD+CD, n = 6) for 5 months. To investigate the effect of angiotensin(1-7) transgenic rats, expressing an angiotensin(1-7)-producing fusion protein in testis were used. These transgenic rats also received a 5 month's feeding period with either chow (TGR+chow, n = 6) or cafeteria diet (TGR+CD, n = 6), respectively. Hemodynamic measurements (pressure-volume loops) were carried out to assess cardiac function and blood pressure. Subsequently, hearts were explanted and investigated according to the Langendorff technique. Furthermore, cardiac remodeling in these animals was investigated histologically. Results:After 5 months cafeteria diet feeding rats showed a significantly increased body weight, which could be prevented in transgenic rats. However, there was no effect on cardiac performance after cafeteria diet in non-transgenic and transgenic rats. Moreover, overexpression of angiotensin(1-7) deteriorated cardiac contractility as indicated by impaired dp/dt. Furthermore, histological analysis revealed that cafeteria diet led to myocardial fibrosis in both, control and transgenic rats and this was not inhibited by an overproduction of angiotensin(1-7). Conclusion:These results indicate that an overexpression of circulating angiotensin(1-7) prevents a cafeteria diet-induced increase in body weight, but does not affect cardiac performance in this experimental rat model of obesity. Furthermore, overexpression of angiotensin(1-7) alone resulted in an impairment of cardiac function. PMID:26733884

  15. Experimental demonstrations of all-optical networking functions for WDM optical networks

    NASA Astrophysics Data System (ADS)

    Gurkan, Deniz

    The deployment of optical networks will enable high capacity links between users but will introduce the problems associated with transporting and managing more channels. Many network functions should be implemented in optical domain; main reasons are: to avoid electronic processing bottlenecks, to achieve data-format and data-rate independence, to provide reliable and cost efficient control and management information, to simultaneously process multiple wavelength channel operation for wavelength division multiplexed (WDM) optical networks. The following novel experimental demonstrations of network functions in the optical domain are presented: Variable-bit-rate recognition of the header information in a data packet. The technique is reconfigurable for different header sequences and uses optical correlators as look-up tables. The header is processed and a signal is sent to the switch for a series of incoming data packets at 155 Mb/s, 622 Mb/s, and 2.5 Gb/s in a reconfigurable network. Simultaneous optical time-slot-interchange and wavelength conversion of the bits in a 2.5-Gb/s data stream to achieve a reconfigurable time/wavelength switch. The technique uses difference-frequency-generation (DFG) for wavelength conversion and fiber Bragg gratings (FBG) as wavelength-dependent optical time buffers. The WDM header recognition module simultaneously recognizing two header bits on each of two 2.5-Gbit/s WDM packet streams. The module is tunable to enable reconfigurable look-up tables. Simultaneous and independent label swapping and wavelength conversion of two WDM channels for a multi-protocol label switching (MPLS) network. Demonstration of label swapping of distinct 8-bit-long labels for two WDM data channels is presented. Two-dimensional code conversion module for an optical code-division multiple-access (O-CDMA) local area network (LAN) system. Simultaneous wavelength conversion and time shifting is achieved to enable flexible code conversion and increase code re

  16. Shifts in microbial community structure and function in stream sediments during experimentally simulated riparian succession.

    PubMed

    Frossard, Aline; Gerull, Linda; Mutz, Michael; Gessner, Mark O

    2013-05-01

    Successional changes of terrestrial vegetation can profoundly influence stream ecosystem structure and function. We hypothesized that microbial enzyme production and community structure in stream beds depend on terrestrial litter inputs that reflect different stages of riparian succession. Outdoor experimental channels were supplied with leaf-litter of varying quantities and qualities to mimic litter supply during five successional stages: (1) an initial biofilm stage; (2) an open-land stage with grass litter; (3) a transitional stage with mixed grass and birch litter; (4) an early forest stage with birch litter; and (5) an advanced forest stage with 2.5 × the amount of birch litter. Mean potential activities of nitrogen- and phosphorus-acquiring enzymes in sediments (20.7 and 67.3 μmol g(-1) dry mass) were 12-70 times greater than those of carbon-acquiring enzymes (0.96-1.71 μmol g(-1) dry mass), with the former reduced 1.3-8.3-fold in channels with tree litter. These patterns could suggest gradually diminishing nutrient limitation of microbial activity during riparian succession, potentially linked both to an increasing supply by the added litter and to a lower nutrient demand as algal biomass and labile carbon supply by photosynthetic exudates declined. As the observed shifts in nutrient-acquiring enzymes were reflected in changes of sediment microbial communities, these results indicate that both the type and density of terrestrial vegetation control microbial community structure and function in stream sediments, particularly enzyme production related to nutrient cycling.

  17. Experimental Validation of Depth Cameras for the Parameterization of Functional Balance of Patients in Clinical Tests

    PubMed Central

    Moreno, Francisco-Ángel; Merchán-Baeza, José Antonio; González-Sánchez, Manuel; González-Jiménez, Javier; Cuesta-Vargas, Antonio I.

    2017-01-01

    In clinical practice, patients’ balance can be assessed using standard scales. Two of the most validated clinical tests for measuring balance are the Timed Up and Go (TUG) test and the MultiDirectional Reach Test (MDRT). Nowadays, inertial sensors (IS) are employed for kinematic analysis of functional tests in the clinical setting, and have become an alternative to expensive, 3D optical motion capture systems. In daily clinical practice, however, IS-based setups are yet cumbersome and inconvenient to apply. Current depth cameras have the potential for such application, presenting many advantages as, for instance, being portable, low-cost and minimally-invasive. This paper aims at experimentally validating to what extent this technology can substitute IS for the parameterization and kinematic analysis of the TUG and the MDRT tests. Twenty healthy young adults were recruited as participants to perform five different balance tests while kinematic data from their movements were measured by both a depth camera and an inertial sensor placed on their trunk. The reliability of the camera’s measurements is examined through the Interclass Correlation Coefficient (ICC), whilst the Pearson Correlation Coefficient (r) is computed to evaluate the correlation between both sensor’s measurements, revealing excellent reliability and strong correlations in most cases. PMID:28241455

  18. Experimental Modification of Rat Pituitary Prolactin Cell Function During and After Spaceflight

    NASA Technical Reports Server (NTRS)

    Hymer, W. C.; Salada, T.; Avery, L.; Grindeland, R. E.

    1996-01-01

    Experimental modification of rat pituitary prolactin cell function during and after spaceflight. This study was done to evaluate the effects of microgravity on prolactin (PRL) cells of the male rat pituitary gland. We used the identical passive closed-vial cell culture system that was described for the culture of growth hormone cells (W C. Hymer, R. E. Grindeland, T. Salada, P. Nye, E. Grossman, and R Lane). After an 8-day spaceflight, all flight media (containing released PRL), as well as extracts (containing intracellular PRL), contained significantly lower amounts of immunoreactive PRL than their corresponding ground control samples. On the other hand, these same samples, when assessed for their biological activities by two different in vitro lymphocyte assays, yielded disparate results that may reflect posttranslational modifications to the hormone molecule. Other data showed that: (1) the apparent molecular weights of released PRL molecules were not altered by microgravity; but (2) the region from which the PRL cells came (dorsal or ventral) made a significant difference in the amount and activity of PRL released from the flight cells. Because there is much current interest in the role that PRL may play in the regulation of the immune system and because changes in both cellular and humoral immunity accompany spaceflight, this study could help define future microgravity research in this area.

  19. Vibration Prediction Method of Electric Machines by using Experimental Transfer Function and Magnetostatic Finite Element Analysis

    NASA Astrophysics Data System (ADS)

    Saito, A.; Kuroishi, M.; Nakai, H.

    2016-09-01

    This paper concerns the noise and structural vibration caused by rotating electric machines. Special attention is given to the magnetic-force induced vibration response of interior-permanent magnet machines. In general, to accurately predict and control the vibration response caused by the electric machines, it is inevitable to model not only the magnetic force induced by the fluctuation of magnetic fields, but also the structural dynamic characteristics of the electric machines and surrounding structural components. However, due to complicated boundary conditions and material properties of the components, such as laminated magnetic cores and varnished windings, it has been a challenge to compute accurate vibration response caused by the electric machines even after their physical models are available. In this paper, we propose a highly-accurate vibration prediction method that couples experimentally-obtained discrete structural transfer functions and numerically-obtained distributed magnetic-forces. The proposed vibration synthesis methodology has been applied to predict vibration responses of an interior permanent magnet machine. The results show that the predicted vibration response of the electric machine agrees very well with the measured vibration response for several load conditions, for wide frequency ranges.

  20. Regular exercise promotes memory function and enhances hippocampal neuroplasticity in experimental autoimmune encephalomyelitis mice.

    PubMed

    Kim, Tae-Woon; Sung, Yun-Hee

    2017-03-27

    Multiple sclerosis (MS) is a progressive condition affecting the central nervous system (CNS), and is characterized by the development of demyelinated lesions and plaques in the brain and spinal cord. Exercise is beneficial against dementia in elderly patients, so we investigated the effects of exercise on memory in relation to hippocampal demyelination and neuroplasticity in a mouse model of MS (experimental autoimmune encephalomyelitis [EAE]). Mice were randomly divided into three groups: Sham, EAE, and EAE and exercise (EAE+EX). EAE+EX mice exercised five times a week for 4weeks, and all mice performed step-down avoidance tasks in order to verify memory ability. We analyzed changes in myelin basic protein (MBP), 2',3'-Cyclic nucleotide 3'-phosphodiesterase (CNPase), 5-bromo-2'-deoxyuridine (brdU), doublecortin (DCX), bcl-2, bax, TUNEL, caspase-3, and brain derived neurotrophic factor (BDNF) via immunoassay or histological staining. We found decreased memory ability in EAE mice, accompanied by impaired myelination, increased apoptosis and cell proliferation, and decreased BDNF in the hippocampus. The memory decline and changes in demyelination, apoptosis, BDNF, and cell proliferation were partially reversed in EAE+EX mice. Our findings suggest that in patients with MS, regular exercise may benefit cognitive function by rescuing some hippocampal cellular and molecular impairments.

  1. Functional and phenotypic characteristics of testicular macrophages in experimental autoimmune orchitis.

    PubMed

    Rival, C; Theas, M S; Suescun, M O; Jacobo, P; Guazzone, V; van Rooijen, N; Lustig, L

    2008-06-01

    Testicular inflammation with compromised fertility can occur despite the fact that the testis is considered an immunoprivileged organ. Testicular macrophages have been described as cells with an immunosuppressor profile, thus contributing to the immunoprivilege of the testis. Experimental autoimmune orchitis (EAO) is a model of organ-specific autoimmunity and testicular inflammation. EAO is characterized by an interstitial inflammatory mononuclear cell infiltration, damage of the seminiferous tubules and germ cell apoptosis. Here we studied the phenotype and functions of testicular macrophages during the development of EAO. By stereological analysis, we detected an increased number of resident (ED2+) and non-resident (ED1+) macrophages in the testicular interstitium of rats with orchitis. We showed that this increase was mainly due to monocyte recruitment. The in vivo administration of liposomes containing clodronate in rats undergoing EAO led to a reduction in the number of testicular macrophages, which correlated with a decreased incidence and severity of the testicular damage and suggests a pathogenic role of macrophages in EAO. By immunohistochemistry and flow cytometry we detected an increased number of testicular macrophages expressing MHC class II, CD80 and CD86 costimulatory molecules in rats with orchitis. Also, testicular macrophages from rats with EAO showed a higher production of IFNgamma (ELISA). We conclude that testicular macrophages participate in EAO development, and the ED1+ macrophage subset is the main pathogenic subpopulation. They stimulate the immune response through the production of pro-inflammatory cytokines and antigen presentation and thus activation of T cells in the target organ.

  2. Experimental Validation of Depth Cameras for the Parameterization of Functional Balance of Patients in Clinical Tests.

    PubMed

    Moreno, Francisco-Ángel; Merchán-Baeza, José Antonio; González-Sánchez, Manuel; González-Jiménez, Javier; Cuesta-Vargas, Antonio I

    2017-02-22

    In clinical practice, patients' balance can be assessed using standard scales. Two of the most validated clinical tests for measuring balance are the Timed Up and Go (TUG) test and the MultiDirectional Reach Test (MDRT). Nowadays, inertial sensors (IS) are employed for kinematic analysis of functional tests in the clinical setting, and have become an alternative to expensive, 3D optical motion capture systems. In daily clinical practice, however, IS-based setups are yet cumbersome and inconvenient to apply. Current depth cameras have the potential for such application, presenting many advantages as, for instance, being portable, low-cost and minimally-invasive. This paper aims at experimentally validating to what extent this technology can substitute IS for the parameterization and kinematic analysis of the TUG and the MDRT tests. Twenty healthy young adults were recruited as participants to perform five different balance tests while kinematic data from their movements were measured by both a depth camera and an inertial sensor placed on their trunk. The reliability of the camera's measurements is examined through the Interclass Correlation Coefficient (ICC), whilst the Pearson Correlation Coefficient (r) is computed to evaluate the correlation between both sensor's measurements, revealing excellent reliability and strong correlations in most cases.

  3. Neural convergence and divergence in the mammalian cerebral cortex: from experimental neuroanatomy to functional neuroimaging.

    PubMed

    Man, Kingson; Kaplan, Jonas; Damasio, Hanna; Damasio, Antonio

    2013-12-15

    A development essential for understanding the neural basis of complex behavior and cognition is the description, during the last quarter of the twentieth century, of detailed patterns of neuronal circuitry in the mammalian cerebral cortex. This effort established that sensory pathways exhibit successive levels of convergence, from the early sensory cortices to sensory-specific and multisensory association cortices, culminating in maximally integrative regions. It was also established that this convergence is reciprocated by successive levels of divergence, from the maximally integrative areas all the way back to the early sensory cortices. This article first provides a brief historical review of these neuroanatomical findings, which were relevant to the study of brain and mind-behavior relationships and to the proposal of heuristic anatomofunctional frameworks. In a second part, the article reviews new evidence that has accumulated from studies of functional neuroimaging, employing both univariate and multivariate analyses, as well as electrophysiology, in humans and other mammals, that the integration of information across the auditory, visual, and somatosensory-motor modalities proceeds in a content-rich manner. Behaviorally and cognitively relevant information is extracted from and conserved across the different modalities, both in higher order association cortices and in early sensory cortices. Such stimulus-specific information is plausibly relayed along the neuroanatomical pathways alluded to above. The evidence reviewed here suggests the need for further in-depth exploration of the intricate connectivity of the mammalian cerebral cortex in experimental neuroanatomical studies.

  4. Neurosurgery at the crossroads: leadership role of the American Association of Neurological Surgeons. The 1979 AANS presidential address.

    PubMed

    Dohn, D F

    1979-10-01

    The President of the American Association of Neurological Surgeons (AANS) reviews the formative history of the major neurosurgical societies, together with their agreement to consolidate their efforts in the joint AANS. As a united group, the Association has been effective in carrying out relations with other professional organizations and with government. Long-range planning is being pursued steadily to increase the role of organized neurosurgery in maintenance of, and improvement in, patient care, education, and research.

  5. Effects of Physical Activity on Children’s Executive Function: Contributions of Experimental Research on Aerobic Exercise

    PubMed Central

    Best, John R.

    2011-01-01

    Executive function refers to the cognitive processes necessary for goal-directed cognition and behavior, which develop across childhood and adolescence. Recent experimental research indicates that both acute and chronic aerobic exercise promote children’s executive function. Furthermore, there is tentative evidence that not all forms of aerobic exercise benefit executive function equally: Cognitively-engaging exercise appears to have a stronger effect than non-engaging exercise on children’s executive function. This review discusses this evidence as well as the mechanisms that may underlie the association between exercise and executive function. Research from a variety of disciplines is covered, including developmental psychology, kinesiology, cognitive neuroscience, and biopsychology. Finally, these experimental findings are placed within the larger context of known links between action and cognition in infancy and early childhood, and the clinical and practical implications of this research are discussed. PMID:21818169

  6. Improvement of patient satisfaction with the neurosurgery service at a large tertiary care, London-based hospital

    PubMed Central

    Khan, Amad; Naushad Chaudhry, Mohammad; Khalid, Salema; Nandi, Dipankar

    2014-01-01

    Patient satisfaction is central to healthcare provision and the effective running of any surgical unit. Following on from both formal and informal feedback, we decided to look objectively at patient satisfaction with the neurosurgery service at a large tertiary care hospital in London and identify areas that needed improvement within the unit. Patient satisfaction was looked at with respect to four different aspects of the neurosurgery service: the surgeons, ward doctors, nurses, and hospital services. A questionnaire-based cross-sectional study was conducted and once the data were collected a plan of action to improve service provision was put into place. Data were collected from 150 patients over a 3 month period from September to November 2012. Interventions were made and data re-collected from 150 patients from January to March 2013. With regards to satisfaction with the neurosurgery service, 76.7% (n=115) were satisfied; following implementation of our measures for improvement, which included staff education, meetings and posters, this figure increased to 90.6% (n=136, p<0.001 on Chi-square testing). In conclusion, patient satisfaction should be at the crux of patient care, with a strong focus on effective communication skills, and can be improved by identification of issues by direct patient feedback and subsequent action based on this. PMID:26733061

  7. Morbidity associated with 30-day surgical site infection following nonshunt pediatric neurosurgery.

    PubMed

    Sherrod, Brandon A; Rocque, Brandon G

    2017-04-01

    OBJECTIVE Morbidity associated with surgical site infection (SSI) following nonshunt pediatric neurosurgical procedures is poorly understood. The purpose of this study was to analyze acute morbidity and mortality associated with SSI after nonshunt pediatric neurosurgery using a nationwide cohort. METHODS The authors reviewed data from the American College of Surgeons National Surgical Quality Improvement Program-Pediatric (NSQIP-P) 2012-2014 database, including all neurosurgical procedures performed on pediatric patients. Procedures were categorized by Current Procedural Terminology (CPT) codes. CSF shunts were excluded. Deep and superficial SSIs occurring within 30 days of an index procedure were identified. Deep SSIs included deep wound infections, intracranial abscesses, meningitis, osteomyelitis, and ventriculitis. The following outcomes occurring within 30 days of an index procedure were analyzed, along with postoperative time to complication development: sepsis, wound disruption, length of postoperative stay, readmission, reoperation, and death. RESULTS A total of 251 procedures associated with a 30-day SSI were identified (2.7% of 9296 procedures). Superficial SSIs were more common than deep SSIs (57.4% versus 42.6%). Deep SSIs occurred more frequently after epilepsy or intracranial tumor procedures. Superficial SSIs occurred more frequently after skin lesion, spine, Chiari decompression, craniofacial, and myelomeningocele closure procedures. The mean (± SD) postoperative length of stay for patients with any SSI was 9.6 ± 14.8 days (median 4 days). Post-SSI outcomes significantly associated with previous SSI included wound disruption (12.4%), sepsis (15.5%), readmission (36.7%), and reoperation (43.4%) (p < 0.001 for each). Post-SSI sepsis rates (6.3% vs 28.0% for superficial versus deep SSI, respectively; p < 0.001), wound disruption rates (4.9% vs 22.4%, p < 0.001), and reoperation rates (23.6% vs 70.1%, p < 0.001) were significantly greater for patients

  8. Parental Evaluation of a Nurse Practitioner-Developed Pediatric Neurosurgery Website

    PubMed Central

    Vogel, Tina Kovacs; Kleib, Manal; Davidson, Sandra J

    2016-01-01

    Background Parents often turn to the Internet to seek health information about their child’s diagnosis and condition. Information, support, and resources regarding pediatric neurosurgery are scarce, hard to find, and difficult to comprehend. To address this gap, a pediatric nurse practitioner designed a website called the Neurosurgery Kids Fund (NKF). Analyzing the legitimacy of the NKF website for parents seeking health information and fulfilling their social and resource needs is critical to the website’s future development and success. Objective To explore parental usage of the NKF website, track visitor behavior, evaluate usability and design, establish ways to improve user experience, and identify ways to redesign the website. The aim of this study was to assess and evaluate whether a custom-designed health website could meet parents’ health information, support, and resource needs. Methods A multimethod approach was used. Google Analytic usage reports were collected and analyzed for the period of April 23, 2013, to November 30, 2013. Fifty-two online questionnaires that targeted the website’s usability were collected between June 18, 2014, and July 30, 2014. Finally, a focus group was conducted on August 20, 2014, to explore parents’ perceptions and user experiences. Findings were analyzed using an inductive content analysis approach. Results There were a total of 2998 sessions and 8818 page views, with 2.94 pages viewed per session, a 56.20% bounce rate, an average session duration of 2 minutes 24 seconds, and a 56.24% new sessions rate. Results from 52 eligible surveys included that the majority of NKF users were Caucasian (90%), females (92%), aged 36-45 years (48%), with a university or college degree or diploma (69%). Half plan to use the health information. Over half reported turning to the Internet for health information and spending 2 to 4 hours a day online. The most common reasons for using the NKF website were to (1) gather information

  9. Simvastatin preserves diastolic function in experimental hypercholesterolemia independently of its lipid lowering effect

    PubMed Central

    Mannheim, Dallit; Herrmann, Joerg; Bonetti, Piero O.; Lavi, Ronit; Lerman, Lilach O.; Lerman, Amir

    2013-01-01

    Objective: Isolated diastolic dysfunction is present in 40% of heart failure patients. It has been attributed to myocardial fibrosis and related to cardiovascular risk factor exposure. We hypothesized that simvastatin will improve these dynamics in experimental hypercholesterolemia (HC). Methods: Three groups of pigs were studied after 12 weeks of normal (N) diet, HC diet, or HC diet with simvastatin (80 mg/day) treatment. Cardiac function was assessed by electron beam computed tomography (EBCT) and percentage of myocardium occupied by microvessels (myocardial vascular fraction) was calculated by micro-CT. Collagen content was determined by Sirius red staining and confirmed by a quantitative, hydroxyoproline-based assay. Results: Compared with N, LDL serum concentration was higher in HC and HC + simvastatin (1.0 ± 0.1 vs. 7.9 ± 1.7 and 9.6 ± 1.2 mmol/L, p < 0.05 for both). Cardiac early diastolic filling was reduced in HC compared with N (102.4 ± 11.3 vs. 151.1 ± 12.1 mL/s; p < 0.05) but restored in HC + simvastatin (176.8 ± 21.3 mL/s, p < 0.05 vs. HC). Compared with N, myocardial vascular fraction was higher in HC but not in HC + simvastatin (1.98 ± 0.84 vs. 4.48 ± 0.31 and 2.95 ± 0.95%; p < 0.05 for HC vs. N). Myocardial collagen content was higher in HC than in HC + simvastatin and N (4.72 ± 1.03 vs. 1.62 ± 0.12 and 1.21 ± 0.24% area staining; p < 0.05 for HC vs. N), which was attributable mainly to an increase in collagen III (2.90 ± 0.48 vs. 1.62 ± 0.12 and 1.21 ± 0.24% area staining; p < 0.05 for HC vs. N). Conclusions: Simvastatin is able to prevent diastolic dysfunction in experimental HC independent of its lipid lowering effect. This beneficial effect is, at least partially, due to a decrease in myocardial fibrosis and angiogenesis. PMID:21414623

  10. Experimental and numerical determination of the correlation function of level velocities for microwave networks simulating quantum graphs

    NASA Astrophysics Data System (ADS)

    Ławniczak, Michał; Nicolau-Kuklińska, Agata; Hul, Oleh; Masiak, Paweł; Bauch, Szymon; Sirko, Leszek

    2013-03-01

    The parameter-dependent correlation function \\tilde {c}_{\\delta }(\\omega ,\\mathsf {x}) of level velocities is studied experimentally and numerically. The measurements were made for microwave networks simulating quantum graphs. One- and two-port measurements of the scattering matrix \\hat {S} necessary for determining the correlation function \\tilde {c}_{\\delta }(\\omega ,\\mathsf {x}) were realized for the five vertices networks. For the fully connected six vertices network, one-port measurements were made. The obtained experimental and numerical results are compared with the predictions of random matrix theory.

  11. Locomotor function of the dorsal fin in teleost fishes: experimental analysis of wake forces in sunfish.

    PubMed

    Drucker, E G; Lauder, G V

    2001-09-01

    A key evolutionary transformation of the locomotor system of ray-finned fishes is the morphological elaboration of the dorsal fin. Within Teleostei, the dorsal fin primitively is a single midline structure supported by soft, flexible fin rays. In its derived condition, the fin is made up of two anatomically distinct portions: an anterior section supported by spines, and a posterior section that is soft-rayed. We have a very limited understanding of the functional significance of this evolutionary variation in dorsal fin design. To initiate empirical hydrodynamic study of dorsal fin function in teleost fishes, we analyzed the wake created by the soft dorsal fin of bluegill sunfish (Lepomis macrochirus) during both steady swimming and unsteady turning maneuvers. Digital particle image velocimetry was used to visualize wake structures and to calculate in vivo locomotor forces. Study of the vortices generated simultaneously by the soft dorsal and caudal fins during locomotion allowed experimental characterization of median-fin wake interactions. During high-speed swimming (i.e. above the gait transition from pectoral- to median-fin locomotion), the soft dorsal fin undergoes regular oscillatory motion which, in comparison with analogous movement by the tail, is phase-advanced (by 30% of the cycle period) and of lower sweep amplitude (by 1.0 cm). Undulations of the soft dorsal fin during steady swimming at 1.1 bodylength s(-1) generate a reverse von Kármán vortex street wake that contributes 12% of total thrust. During low-speed turns, the soft dorsal fin produces discrete pairs of counterrotating vortices with a central region of high-velocity jet flow. This vortex wake, generated in the latter stage of the turn and posterior to the center of mass of the body, counteracts torque generated earlier in the turn by the anteriorly positioned pectoral fins and thereby corrects the heading of the fish as it begins to translate forward away from the turning stimulus. One

  12. Diminazene Attenuates Pulmonary Hypertension and Improves Angiogenic Progenitor Cell Functions in Experimental Models

    PubMed Central

    Shenoy, Vinayak; Gjymishka, Altin; Jarajapu, Yagna P.; Qi, Yanfei; Afzal, Aqeela; Rigatto, Katya; Ferreira, Anderson J.; Fraga-Silva, Rodrigo A.; Kearns, Patrick; Douglas, Jane Yellowlees; Agarwal, Deepmala; Mubarak, Kamal K.; Bradford, Chastity; Kennedy, William R.; Jun, Joo Y.; Rathinasabapathy, Anandharajan; Bruce, Erin; Gupta, Dipankar; Cardounel, Arturo J.; Mocco, J.; Patel, Jawaharlal M.; Francis, Joseph; Grant, Maria B.; Katovich, Michael J.

    2013-01-01

    Rationale: Studies have demonstrated that angiotensin-converting enzyme 2 (ACE2) plays a protective role against lung diseases, including pulmonary hypertension (PH). Recently, an antitrypanosomal drug, diminazene aceturate (DIZE), was shown to exert an “off-target” effect of enhancing the enzymatic activity of ACE2 in vitro. Objectives: To evaluate the pharmacological actions of DIZE in experimental models of PH. Methods: PH was induced in male Sprague Dawley rats by monocrotaline, hypoxia, or bleomycin challenge. Subsets of animals were simultaneously treated with DIZE. In a separate set of experiments, DIZE was administered after 3 weeks of PH induction to determine whether the drug could reverse PH. Measurements and Main Results: DIZE treatment significantly prevented the development of PH in all of the animal models studied. The protective effects were associated with an increase in the vasoprotective axis of the lung renin-angiotensin system, decreased inflammatory cytokines, improved pulmonary vasoreactivity, and enhanced cardiac function. These beneficial effects were abolished by C-16, an ACE2 inhibitor. Initiation of DIZE treatment after the induction of PH arrested disease progression. Endothelial dysfunction represents a hallmark of PH pathophysiology, and growing evidence suggests that bone marrow–derived angiogenic progenitor cells contribute to endothelial homeostasis. We observed that angiogenic progenitor cells derived from the bone marrow of monocrotaline-challenged rats were dysfunctional and were repaired by DIZE treatment. Likewise, angiogenic progenitor cells isolated from patients with PH exhibited diminished migratory capacity toward the key chemoattractant stromal-derived factor 1α, which was corrected by in vitro DIZE treatment. Conclusions: Our results identify a therapeutic potential of DIZE in PH therapy. PMID:23370913

  13. Kinetics of Bartonella birtlesii Infection in Experimentally Infected Mice and Pathogenic Effect on Reproductive Functions

    PubMed Central

    Boulouis, Henri J.; Barrat, Francine; Bermond, Delphine; Bernex, Florence; Thibault, Danièle; Heller, Rémy; Fontaine, Jean-Jacques; Piémont, Yves; Chomel, Bruno B.

    2001-01-01

    The kinetics of infection and the pathogenic effects on the reproductive function of laboratory mice infected with Bartonella birtlesii recovered from an Apodemus species are described. B. birtlesii infection, as determined by bacteremia, occurred in BALB/c mice inoculated intravenously. Inoculation with a low-dose inoculum (1.5 × 103 CFU) induced bacteremia in only 75% of the mice compared to all of the mice inoculated with higher doses (≥1.5 × 104). Mice became bacteremic for at least 5 weeks (range, 5 to 8 weeks) with a peak ranging from 2 × 103 to 105 CFU/ml of blood. The bacteremia level was significantly higher in virgin females than in males but the duration of bacteremia was similar. In mice infected before pregnancy (n = 20), fetal loss was evaluated by enumerating resorption and fetal death on day 18 of gestation. The fetal death and resorption percentage of infected mice was 36.3% versus 14.5% for controls (P < 0.0001). Fetal suffering was evaluated by weighing viable fetuses. The weight of viable fetuses was significantly lower for infected mice than for uninfected mice (P < 0.0002). Transplacental transmission of Bartonella was demonstrated since 76% of the fetal resorptions tested was culture positive for B. birtlesii. The histopathological analysis of the placentas of infected mice showed vascular lesions in the maternal placenta, which could explain the reproductive disorders observed. BALB/c mice appeared to be a useful model for studying Bartonella infection. This study provides the first evidence of reproductive disorders in mice experimentally infected with a Bartonella strain originating from a wild rodent. PMID:11500400

  14. Rivaling paradigms in psychiatric neurosurgery: adjustability versus quick fix versus minimal-invasiveness

    PubMed Central

    Müller, Sabine; Riedmüller, Rita; van Oosterhout, Ansel

    2015-01-01

    In the wake of deep brain stimulation (DBS) development, ablative neurosurgical procedures are seeing a comeback, although they had been discredited and nearly completely abandoned in the 1970s because of their unethical practice. Modern stereotactic ablative procedures as thermal or radiofrequency ablation, and particularly radiosurgery (e.g., Gamma Knife) are much safer than the historical procedures, so that a re-evaluation of this technique is required. The different approaches of modern psychiatric neurosurgery refer to different paradigms: microsurgical ablative procedures is based on the paradigm ‘quick fix,’ radiosurgery on the paradigm ‘minimal-invasiveness,’ and DBS on the paradigm ‘adjustability.’ From a mere medical perspective, none of the procedures is absolutely superior; rather, they have different profiles of advantages and disadvantages. Therefore, individual factors are crucial in decision-making, particularly the patients’ social situation, individual preferences, and individual attitudes. The different approaches are not only rivals, but also enriching mutually. DBS is preferable for exploring new targets, which may become candidates for ablative microsurgery or radiosurgery. PMID:25883557

  15. "Extremely minimally invasive": recent advances in nanotechnology research and future applications in neurosurgery.

    PubMed

    Mattei, Tobias A; Rehman, Azeem A

    2015-01-01

    The term "nanotechnology" refers to the development of materials and devices that have been designed with specific properties at the nanometer scale (10(-9) m), usually being less than 100 nm in size. Recent advances in nanotechnology have promised to enable visualization and intervention at the subcellular level, and its incorporation to future medical therapeutics is expected to bring new avenues for molecular imaging, targeted drug delivery, and personalized interventions. Although the central nervous system presents unique challenges to the implementation of new therapeutic strategies involving nanotechnology (such as the heterogeneous molecular environment of different CNS regions, the existence of multiple processing centers with different cytoarchitecture, and the presence of the blood-brain barrier), numerous studies have demonstrated that the incorporation of nanotechnology resources into the armamentarium of neurosurgery may lead to breakthrough advances in the near future. In this article, the authors present a critical review on the current 'state-of-the-art' of basic research in nanotechnology with special attention to those issues which present the greatest potential to generate major therapeutic progresses in the neurosurgical field, including nanoelectromechanical systems, nano-scaffolds for neural regeneration, sutureless anastomosis, molecular imaging, targeted drug delivery, and theranostic strategies.

  16. Theoretical and In-Vivo Investigation of Optical Reflectance from Human Brain to Assist Neurosurgery

    NASA Astrophysics Data System (ADS)

    Johns, Maureen; Giller, Cole A.; Liu, Hanli

    1998-10-01

    Parkinson's disease (PD) is a chronic, progressive disease involving the globus pallidus (GP), which is a gray matter mass, surrounded by white matter deep within the brain. During a neurosurgery procedure, a thin probe is inserted into the GP to create a lesion that often relieves the cardinal symptoms of PD. The goal of this study is to develop an optical method to accurately locate the GP border. In theory, Monte Carlo simulations were performed to predict the optical reflectance from brain tissue. In experiment, a portable, real-time display spectrometer with a fiber optic reflectance probe was developed and used during human surgery. Optical reflectance values were recorded at 1 mm intervals to obtain a spatial profile of the tissue as the probe passed through regions of gray and white matter. The simulation and in vivo studies of the reflectance from the brain are in good agreement with one another. The clinical data show that the reflectance from gray matter is approximately 50% or less than that from white matter between 650 and 800 nm. A slope algorithm is developed to distinguish gray and white matter in vivo. This study provides previously unknown optical reflectance of the human brain.

  17. Rivaling paradigms in psychiatric neurosurgery: adjustability versus quick fix versus minimal-invasiveness.

    PubMed

    Müller, Sabine; Riedmüller, Rita; van Oosterhout, Ansel

    2015-01-01

    In the wake of deep brain stimulation (DBS) development, ablative neurosurgical procedures are seeing a comeback, although they had been discredited and nearly completely abandoned in the 1970s because of their unethical practice. Modern stereotactic ablative procedures as thermal or radiofrequency ablation, and particularly radiosurgery (e.g., Gamma Knife) are much safer than the historical procedures, so that a re-evaluation of this technique is required. The different approaches of modern psychiatric neurosurgery refer to different paradigms: microsurgical ablative procedures is based on the paradigm 'quick fix,' radiosurgery on the paradigm 'minimal-invasiveness,' and DBS on the paradigm 'adjustability.' From a mere medical perspective, none of the procedures is absolutely superior; rather, they have different profiles of advantages and disadvantages. Therefore, individual factors are crucial in decision-making, particularly the patients' social situation, individual preferences, and individual attitudes. The different approaches are not only rivals, but also enriching mutually. DBS is preferable for exploring new targets, which may become candidates for ablative microsurgery or radiosurgery.

  18. A rare case of symmetrical four limb gangrene following emergency neurosurgery

    PubMed Central

    Phan, Pho NH; Acharya, Vikas; Parikh, Dhruv; Shad, Amjad

    2015-01-01

    Introduction The authors report a case of symmetrical peripheral gangrene (SPG) following emergency neurosurgery. Presentation of case A 35-year-old female presented to hospital in Thailand with nausea, headache, and subsequent seizures. She was found to have a large intracranial space-occupying lesion with mass effect. Following emergency surgical debulking and decompression, she suffered from severe sepsis with multiple organ failure, treated with high dose intravenous vasopressors and developed secondary gangrene in all four limbs. She was repatriated to the UK with a baseline GCS of 8 and multiple postoperative medical complications. With initial conservative management, the patient made a prolonged but satisfactory progression to recovery prior to semi-elective debridement and selected digit amputation of the gangrene. Discussion This is the first reported case of four limb symmetrical peripheral gangrene following an emergency craniotomy. Conclusion Although rare, SPG is a substantial complication with high mortality and morbidity and therefore should be especially taken into account for emergency intracranial pathologies in neurosurgical patients, particularly if they require emergency surgery. PMID:26406313

  19. Computational and in vivo investigation of optical reflectance from human brain to assist neurosurgery.

    PubMed

    Johns, M; Giller, C; Liu, H

    1998-10-01

    Parkinson's disease (PD) is a chronic, progressive disease involving the globus pallidus (GP), which is a gray matter mass, surrounded by white matter deep within the brain. During a neurosurgery procedure, a thin probe is inserted into the GP to create a lesion that often relieves the cardinal symptoms of PD. The goal of this study is to develop an optical method to accurately locate the GP border. In theory, Monte Carlo simulations were performed to predict the optical reflectance from brain tissue. In experiment, a portable, real-time display spectrometer with a fiber optic reflectance probe was developed and used during human surgery. Optical reflectance values were recorded at 1 mm intervals to obtain a spatial profile of the tissue as the probe passed through regions of gray and white matter. The simulation and in vivo studies of the reflectance from the brain are in good agreement with one another. The clinical data show that the reflectance from gray matter is approximately 50% or less than that from white matter between 650 and 800 nm. A slope algorithm is developed to distinguish gray and white matter in vivo. This study provides previously unknown optical reflectance of the human brain. © 1998 Society of Photo-Optical Instrumentation Engineers.

  20. Automated rejection of contaminated surface measurements for improved surface registration in image guided neurosurgery.

    PubMed

    Bucholz, R; Macneil, W; Fewings, P; Ravindra, A; McDurmont, L; Baumann, C

    2000-01-01

    Most image guided Neurosurgery employs adhesively mounted external fiducials for registration of medical images to the surgical workspace. Due to high logistical costs associated with these artificial landmarks, we strive to eliminate the need for these markers. At our institution, we developed a handheld laser stripe triangulation device to capture the surface contours of the patient's head while oriented for surgery. Anatomical surface registration algorithms rely on the assumption that the patient's anatomy bears the same geometry as the 3D model of the patient constructed from the imaging modality employed. During the time interval from which the patient is imaged and placed in the Mayfield head clamp in the operating room, the skin of the head bulges at the pinsite and the skull fixation equipment itself optically interferes with the image capture laser. We have developed software to reject points belonging to objects of known geometry while calculating the registration. During the course of development of the laser scanning unit, we have acquired surface contours of 13 patients and 2 cadavers. Initial analysis revealed that this automated rejection of points improved the registrations in all cases, but the accuracy of the fiducial method was not surpassed. Only points belonging to the offending instrument are removed. Skin bulges caused by the clamps and instruments remain in the data. We anticipate that careful removal of the points in these skin bulges will yield registrations that at least match the accuracy of the fiducial method.

  1. Fiber-based tissue identification for electrode placement in deep brain stimulation neurosurgery (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    DePaoli, Damon T.; Lapointe, Nicolas; Goetz, Laurent; Parent, Martin; Prudhomme, Michel; Cantin, Léo.; Galstian, Tigran; Messaddeq, Younès.; Côté, Daniel C.

    2016-03-01

    Deep brain stimulation's effectiveness relies on the ability of the stimulating electrode to be properly placed within a specific target area of the brain. Optical guidance techniques that can increase the accuracy of the procedure, without causing any additional harm, are therefore of great interest. We have designed a cheap optical fiber-based device that is small enough to be placed within commercially available DBS stimulating electrodes' hollow cores and that is capable of sensing biological information from the surrounding tissue, using low power white light. With this probe we have shown the ability to distinguish white and grey matter as well as blood vessels, in vitro, in human brain samples and in vivo, in rats. We have also repeated the in vitro procedure with the probe inserted in a DBS stimulating electrode and found the results were in good agreement. We are currently validating a second fiber optic device, with micro-optical components, that will result in label free, molecular level sensing capabilities, using CARS spectroscopy. The final objective will be to use this data in real time, during deep brain stimulation neurosurgery, to increase the safety and accuracy of the procedure.

  2. Low end interactive image-directed neurosurgery. Update on rudimentary augmented reality used in epilepsy surgery.

    PubMed

    Doyle, W K

    1996-01-01

    Our experience with a very low end interactive image-directed (IIDS) neurosurgical system is presented. The system was developed by the author and consists of a personal desktop computer and a magnetic field digitizer. This low cost solution was pursued as an alternative to available commercial devices which were expensive and not readily modifiable for novel ideas and new applications targeted for Epilepsy surgery. The rationale and description of the system was presented last year at Medicine Meets Virtual Reality III. Included in that detailed report were the fundamental mathematics forming the basics of transformation between the surgical and the digital data spaces. Since then the system has been used in an additional 20 cases now totaling 40 in all. Its advantages and short comings will be described. The theoretical advantages of magnetic field technology over other localization methods is reviewed. Also, our experience with alternative low cost off-the-shelf interfacing devices and other related modifications are described. We have accumulated clinical data to suggest that craniotomy sizes have been reduced, electrode placement has been improved, and that interactive image-directed techniques offer advantages over other common intra-operative localization modalities such as ultrasound. Our conclusion is that interactive image-directed techniques improve neurosurgery and that inexpensive enabling technology is already available providing the technological substrate for low cost devices using virtual reality notions for surgery and medicine. This particular technology offers advantages to traditional surgical techniques demonstrating the attractiveness of rudimentary virtual reality medical applications.

  3. Cost analysis of a project to digitize classic articles in neurosurgery*

    PubMed Central

    Bauer, Kathleen

    2002-01-01

    In summer 2000, the Cushing/Whitney Medical Library at Yale University began a demonstration project to digitize classic articles in neurosurgery from the late 1800s and early 1900s. The objective of the first phase of the project was to measure the time and costs involved in digitization, and those results are reported here. In the second phase, metadata will be added to the digitized articles, and the project will be publicized. Thirteen articles were scanned using optical character recognition (OCR) software, and the resulting text files were carefully proofread. Time for photocopying, scanning, and proofreading were recorded. This project achieved an average cost per item (total pages plus images) of $4.12, a figure at the high end of average costs found in other studies. This project experienced high costs for two reasons. First, the articles contained many images, which required extra processing. Second, the older fonts and the poor condition of many of these articles complicated the OCR process. The average article cost $84.46 to digitize. Although costs were high, the selection of historically important articles maximized the benefit gained from the investment in digitization. PMID:11999182

  4. Use of hydrogen peroxide in neurosurgery: case series of cardiovascular complications

    PubMed Central

    Spiriev, Toma; Prabhakar, Hemanshu; Sandu, Nora; Tzekov, Christo; Kondoff, Slavomir; Laleva, Lili; Schaller, Bernhard

    2012-01-01

    Objectives Postoperative complications induced by hydrogen peroxide (H2O2) are described in the neurosurgical literature and mainly involve oxygen venous emboli, postoperative pneumocephalus; some of them even fatal. However, recently there are more and more published case reports for significant cardiac dysrhythmia related to the use of this chemical agent during routine neurosurgical interventions. Design Retrospective, two-centre study. Setting Retrospective review of clinical/radiological documentation (including preoperative medical history, operation report and intraoperative anesthesiology data charts). Participants Patients scheduled for cranial neurosurgical interventions. Main outcome measures Intraoperative occurrence of trigeminocardiac reflex (TCR), according the earlier defined by our group criteria, or other severe cardiovascular complications related to the intraoperative use of H2O2. Results Five cases were included in the study fulfilling the strict inclusion/exclusion criteria. Two of the cases were recognized as intraoperative TCR, in the other three cases the cardiovascular effects were possibly due to TCR in one, mechanical stimulation of vital centre in anterior hypothalamus, brainstem, or either mechanical or thermal action of H2O2. Conclusions According to this two-centre study, we can give, for the first time, evidence that cardiovascular complications according to the intraoperative use of H2O2 in neurosurgery are not rare with an incidence of 3%. Special reference is given to the occurrence of the TCR in this context. PMID:22299072

  5. Classification of the EEG during neurosurgery. Parametric identification and Kalman filtering compared.

    PubMed

    Cerutti, S; Liberati, D; Avanzini, G; Franceschetti, S; Panzica, F

    1986-07-01

    A procedure is described which aims to classify an EEG recorded during neurosurgery, for example intracerebral aneurysm clipping. A parametric approach is used; it employs auto-regressive (AR) modelling and Kalman filtering to quantify directly the dynamics of the EEG generating mechanism, supposing it to be a linear, time-invariant system driven by white noise. The results of this EEG processing are analysed together with simultaneous values of arterial blood pressure (ABP) as surgery of this kind is carried out under conditions of controlled hypotension. The object is to compare the sensitivity of ABP data with that obtained from the EEG and so provide an early warning of a potentially dangerous non-physiological state induced by the hypotensive drug (in this case sodium nitroprusside). Some methodological comments on the correct implementation of these algorithms are given and the procedure is compared with similar approaches which have appeared in the literature during the last few years. Particular emphasis is placed on the power spectral analysis of the signal by pointing out a method for spectral decomposition, related to AR power density estimation, which permits the separation of single spectral components in terms of central frequencies and their associated power. Other potential applications of this method are in long term EEG monitoring for the detection of changes due for example to drug infusion, to fast transient events, or to changes in the stationary condition.

  6. Modeling functional Magnetic Resonance Imaging (fMRI) experimental variables in the Ontology of Experimental Variables and Values (OoEVV).

    PubMed

    Burns, Gully A P C; Turner, Jessica A

    2013-11-15

    Neuroimaging data is raw material for cognitive neuroscience experiments, leading to scientific knowledge about human neurological and psychological disease, language, perception, attention and ultimately, cognition. The structure of the variables used in the experimental design defines the structure of the data gathered in the experiments; this in turn structures the interpretative assertions that may be presented as experimental conclusions. Representing these assertions and the experimental data which support them in a computable way means that they could be used in logical reasoning environments, i.e. for automated meta-analyses, or linking hypotheses and results across different levels of neuroscientific experiments. Therefore, a crucial first step in being able to represent neuroimaging results in a clear, computable way is to develop representations for the scientific variables involved in neuroimaging experiments. These representations should be expressive, computable, valid, extensible, and easy-to-use. They should also leverage existing semantic standards to interoperate easily with other systems. We present an ontology design pattern called the Ontology of Experimental Variables and Values (OoEVV). This is designed to provide a lightweight framework to capture mathematical properties of data, with appropriate 'hooks' to permit linkage to other ontology-driven projects (such as the Ontology of Biomedical Investigations, OBI). We instantiate the OoEVV system with a small number of functional Magnetic Resonance Imaging datasets, to demonstrate the system's ability to describe the variables of a neuroimaging experiment. OoEVV is designed to be compatible with the XCEDE neuroimaging data standard for data collection terminology, and with the Cognitive Paradigm Ontology (CogPO) for specific reasoning elements of neuroimaging experimental designs.

  7. Functional modelling of an equine bronchoalveolar lavage fluid proteome provides experimental confirmation and functional annotation of equine genome sequences.

    PubMed

    Bright, L A; Mujahid, N; Nanduri, B; McCarthy, F M; Costa, L R R; Burgess, S C; Swiderski, C E

    2011-08-01

    The equine genome sequence enables the use of high-throughput genomic technologies in equine research, but accurate identification of expressed gene products and interpreting their biological relevance require additional structural and functional genome annotation. Here, we employ the equine genome sequence to identify predicted and known proteins using proteomics and model these proteins into biological pathways, identifying 582 proteins in normal cell-free equine bronchoalveolar lavage fluid (BALF). We improved structural and functional annotation by directly confirming the in vivo expression of 558 (96%) proteins, which were computationally predicted previously, and adding Gene Ontology (GO) annotations for 174 proteins, 108 of which lacked functional annotation. Bronchoalveolar lavage is commonly used to investigate equine respiratory disease, leading us to model the associated proteome and its biological functions. Modelling of protein functions using Ingenuity Pathway Analysis identified carbohydrate metabolism, cell-to-cell signalling, cellular function, inflammatory response, organ morphology, lipid metabolism and cellular movement as key biological processes in normal equine BALF. Comparative modelling of protein functions in normal cell-free bronchoalveolar lavage proteomes from horse, human, and mouse, performed by grouping GO terms sharing common ancestor terms, confirms conservation of functions across species. Ninety-one of 92 human GO categories and 105 of 109 mouse GO categories were conserved in the horse. Our approach confirms the utility of the equine genome sequence to characterize protein networks without antibodies or mRNA quantification, highlights the need for continued structural and functional annotation of the equine genome and provides a framework for equine researchers to aid in the annotation effort.

  8. Two-parameter Fermi function fits to experimental charge and point-proton densities for 208Pb

    NASA Astrophysics Data System (ADS)

    Jones, Adam B.; Brown, B. Alex

    2014-12-01

    We use the model-independent experimental charge density for 208Pb to determine a model-independent point-proton density. An improved two-parameter Fermi function representation for the this point-proton density provides input for the analysis of experiments for the neutron density interpreted in terms of neutron skin and halo properties of 208Pb.

  9. Experimental Determination of GPR Groundwave Sampling Depth as a Function of Data Acquisition Parameters

    NASA Astrophysics Data System (ADS)

    Crist, T. L.; Benda, A.; Grote, K. R.

    2010-12-01

    Accurate measurements of near-surface soil water content are important for many applications, including environmental remediation, precision agriculture, and climate modeling. Conventional methods of measuring soil water content are usually limited to point measurements or shallow remote sensing techniques, but several researchers have shown that Ground Penetrating Radar (GPR) groundwaves can be used to accurately measure the near-surface soil water content rapidly and with high resolution. Previous laboratory research and modeling studies have shown that the sampling depth of GPR groundwaves is frequency dependent, and some modeling studies indicated that the sampling depth also depends on antenna separation. Thus, multi-frequency groundwave data or data acquired at different antenna separations might be used to create a vertical soil water content profile. However, the experimental data currently available were generated using sharp interfaces in water content, where a very wet soil was directly adjacent to a very dry soil; in natural environments, the soil water content distribution typically changes more gradually with depth. The previous experimental and modeling data also use variable-offset surveys to estimate a single sampling depth, so the effect of antenna separation on sampling depth cannot be determined from these studies. This experiment investigates how the groundwave sampling depth varies as a function of frequency and antenna separation in a natural soil environment during an infiltration experiment. The study area was a 2.5 m by 4.5 plot with no significant topography. To monitor changes in water content with depth throughout the experiment, eight boreholes were dug along the perimeter of the study area, and Time Domain Reflectometry (TDR) probes were installed at 7.5 cm vertical intervals to a depth of 53 cm in each borehole. TDR data were acquired every 10 minutes throughout the experiment. GPR data were acquired over the initially dry plot area

  10. Effects of estrogen on functional and neurological recovery after spinal cord injury: An experimental study with rats

    PubMed Central

    Letaif, Olavo Biraghi; Cristante, Alexandre Fogaça; de Barros Filho, Tarcísio Eloy Pessoa; Ferreira, Ricardo; dos Santos, Gustavo Bispo; da Rocha, Ivan Dias; Marcon, Raphael Martus

    2015-01-01

    OBJECTIVES: To evaluate the functional and histological effects of estrogen as a neuroprotective agent after a standard experimentally induced spinal cord lesion. METHODS: In this experimental study, 20 male Wistar rats were divided into two groups: one group with rats undergoing spinal cord injury (SCI) at T10 and receiving estrogen therapy with 17-beta estradiol (4mg/kg) immediately following the injury and after the placement of skin sutures and a control group with rats only subjected to SCI. A moderate standard experimentally induced SCI was produced using a computerized device that dropped a weight on the rat's spine from a height of 12.5 mm. Functional recovery was verified with the Basso, Beattie and Bresnahan scale on the 2nd, 7th, 14th, 21st, 28th, 35th and 42nd days after injury and by quantifying the motor-evoked potential on the 42nd day after injury. Histopathological evaluation of the SCI area was performed after euthanasia on the 42nd day. RESULTS: The experimental group showed a significantly greater functional improvement from the 28th to the 42nd day of observation compared to the control group. The experimental group showed statistically significant improvements in the motor-evoked potential compared with the control group. The results of pathological histomorphometry evaluations showed a better neurological recovery in the experimental group, with respect to the proportion and diameter of the quantified nerve fibers. CONCLUSIONS: Estrogen administration provided benefits in neurological and functional motor recovery in rats with SCI beginning at the 28th day after injury. PMID:26598084

  11. Power and power-to-flow reactivity transfer functions in EBR-II (Experimental Breeder Reactor II) fuel

    SciTech Connect

    Grimm, K.N.; Meneghetti, D. )

    1989-11-01

    Reactivity transfer functions are important in determining the reactivity history during a power transient. Overall nodal transfer functions have been calculated for different subassembly types in the Experimental Breeder Reactor II (EBR-II). Steady-state calculations for temperature changes and, hence, reactivities for power changes have been separated into power and power-to-flow-dependent terms. Axial nodal transfer functions separated into power and power-to-flow-dependent components are reported in this paper for a typical EBR-II fuel pin. This provides an improved understanding of the time dependence of these components in transient situations.

  12. [Report of the World Federation of Neurosurgical Societies (WFNS) international course and Cameroon Neurosurgery Society Congress (CNS) Yaoundé (Cameroon), 1st--4th October 2007].

    PubMed

    Eyenga, V C; Ndoumbe, A; Eloundou, N J

    2008-04-01

    Neurosurgery remains a very marginal activity in sub-Saharan Africa. In this part of the world which counts nearly 40 countries, some do not have a single neurosurgeon, some have one to five, the number of ten neurosurgeons per country remaining an exception! In its concern of popularizing and of developing neurosurgery worldwide, the WFNS organized an international course in Africa, October 2007 2nd-3rd in Yaoundé (Cameroon). The Cameroon Neurosurgery Society (CNS) took this opportunity to organize its very first congress in the presence of the WFNS delegation from October 1st to 4th, 2007. The joint meeting with the WFNS was baptized the "African Week of Neurosurgery". This special event was a first in sub-Saharan Africa. The delegation of the WFNS, led by Professor J. Brotchi (Belgium) President of the WFNS, was made up of Professors A. Sousa (Brazil), Mr. Choux (France), N. Tribolet (Swiss), M. Arraez (Spain), A. Bricolo (Italy), A. Kamlichi (Morocco), G. Dechambenoit (France), K. Kalangu (Zimbabwe). Twenty three neurosurgeons coming from nine African countries (Cameroon, Nigeria, Gabon, Congo, Niger, Burkina Faso, Ivory Coast, Senegal, and Guinea) took an active part in work. The scientific success of this event led to the creation of the "Association of Neurological Surgeons of Africa (ANSA)" which will be the WFNS-Africa interface in order to insure the development of neurosurgery in Africa.

  13. Experimental determination of single-event upset (SEU) as a function of collected charge in bipolar integrated circuits

    NASA Technical Reports Server (NTRS)

    Zoutendyk, J. A.; Malone, C. J.; Smith, L. S.

    1984-01-01

    Single-Event Upset (SEU) in bipolar integrated circuits (ICs) is caused by charge collection from ion tracks in various regions of a bipolar transistor. This paper presents experimental data which have been obtained wherein the range-energy characteristics of heavy ions (Br) have been utilized to determine the cross section for soft-error generation as a function of charge collected from single-particle tracks which penetrate a bipolar static RAM. The results of this work provide a basis for the experimental verification of circuit-simulation SEU modeling in bipolar ICs.

  14. The DTI Challenge: Towards Standardized Evaluation of Diffusion Tensor Imaging Tractography for Neurosurgery

    PubMed Central

    Pujol, Sonia; Wells, William; Pierpaoli, Carlo; Brun, Caroline; Gee, James; Cheng, Guang; Vemuri, Baba; Commowick, Olivier; Prima, Sylvain; Stamm, Aymeric; Goubran, Maged; Khan, Ali; Peters, Terry; Neher, Peter; Maier-Hein, Klaus H.; Shi, Yundi; Tristan-Vega, Antonio; Veni, Gopalkrishna; Whitaker, Ross; Styner, Martin; Westin, Carl-Fredrik; Gouttard, Sylvain; Norton, Isaiah; Chauvin, Laurent; Mamata, Hatsuho; Gerig, Guido; Nabavi, Arya; Golby, Alexandra; Kikinis, Ron

    2015-01-01

    Background and Purpose Diffusion tensor imaging tractography reconstruction of white matter pathways can help guide brain tumor resection. However, DTI tracts are complex mathematical objects and the validity of tractography-derived information in clinical settings has yet to be fully established. To address this issue, we initiated the DTI Challenge, an international working group of clinicians and scientists whose goal was to provide standardized evaluation of tractography methods for neurosurgery. The purpose of this empirical study was to evaluate different tractography techniques in the first DTI Challenge workshop. Methods Eight international teams from leading institutions reconstructed the pyramidal tract in four neurosurgical cases presenting with a glioma near the motor cortex. Tractography methods included deterministic, probabilistic, filtered, and global approaches. Standardized evaluation of the tracts consisted in the qualitative review of the pyramidal pathways by a panel of neurosurgeons and DTI experts and the quantitative evaluation of the degree of agreement among methods. Results The evaluation of tractography reconstructions showed a great inter-algorithm variability. Although most methods found projections of the pyramidal tract from the medial portion of the motor strip, only a few algorithms could trace the lateral projections from the hand, face, and tongue area. In addition, the structure of disagreement among methods was similar across hemispheres despite the anatomical distortions caused by pathological tissues. Conclusions The DTI Challenge provides a benchmark for the standardized evaluation of tractography methods on neurosurgical data. This study suggests that there are still limitations to the clinical use of tractography for neurosurgical decision-making. PMID:26259925

  15. Max Brödel: his art, legacy, and contributions to neurosurgery through medical illustration.

    PubMed

    Patel, Smruti K; Couldwell, William T; Liu, James K

    2011-07-01

    Max Brödel is considered the father of modern medical illustration. This report reviews his contributions to neurosurgery as a medical illustrator. Max Brödel, a young artist from Leipzig, Germany, was hired at Johns Hopkins Hospital in 1894, where he illustrated an operative textbook of gynecology for Howard A. Kelly. Although Brödel did not have any formal medical training, he quickly acquired knowledge of anatomy, pathology, physiology, and surgery. Brödel's extraordinary illustrations were characterized by an aerial perspective that conveyed the surgeon's operative viewpoint and precise surgical anatomy. He masterfully incorporated tissue realism with cross-sectional anatomy to accentuate concepts while maintaining topographical accuracy. Brödel's reputation spread quickly and resulted in collaborations with prominent surgeons, such as Cushing, Halsted, and Dandy. Cushing, who also possessed artistic talent, became a pupil of Brödel and remained a very close friend. In 1911, Brödel was appointed the director of the Department of Art as Applied to Medicine at Johns Hopkins, the first academic department of its kind in the world. For the next several decades, he trained generations of renowned medical illustrators. Just as Osler, Halsted, and Cushing passed their skills and knowledge to future leaders of medicine and surgery, Brödel did the same for the field of medical illustration. The advancement of neurosurgical education has been greatly facilitated by Max Brödel's artistic contributions. His unique ability to synthesize art and medicine resulted in timeless illustrations that remain indispensable to surgeons. The art produced by his legacy of illustrators continues to flourish in neurosurgical literature today.

  16. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    NASA Astrophysics Data System (ADS)

    Alva-Sánchez, Héctor; Reynoso-Mejía, Alberto; Casares-Cruz, Katiuzka; Taboada-Barajas, Jesús

    2014-11-01

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  17. Does chlorhexidine and povidone-iodine preoperative antisepsis reduce surgical site infection in cranial neurosurgery?

    PubMed

    Davies, B M; Patel, H C

    2016-07-01

    Introduction Surgical site infection (SSI) is a significant cause of postoperative morbidity and mortality. Effective preoperative antisepsis is a recognised prophylactic, with commonly used agents including chlorhexidine (CHG) and povidone-iodine (PVI). However, there is emerging evidence to suggest an additional benefit when they are used in combination. Methods We analysed data from our prospective SSI database on patients undergoing clean cranial neurosurgery between October 2011 and April 2014. We compared the case-mix adjusted odds of developing a SSI in patients undergoing skin preparation with CGH or PVI alone or in combination. Results SSIs were detected in 2.6% of 1146 cases. Antisepsis with PVI alone was performed in 654 (57%) procedures, while 276 (24%) had CHG alone and 216 (19%) CHG and PVI together. SSIs were associated with longer operating time (p<0.001) and younger age (p=0.03). Surgery type (p<0.001) and length of operation (p<0.001) were significantly different between antisepsis groups. In a binary logistic regression model, CHG and PVI was associated with a significant reduction in the likelihood of developing an SSI (adjusted odds ratio [AOR] 0.12, 95% confidence interval [CI] 0.02-0.63) than either agent alone. There was no difference in SSI rates between CHG and PVI alone (AOR 0.60, 95% CI 0.24-1.5). Conclusions Combination skin preparation with CHG and PVI significantly reduced SSI rates compared to CHG or PVI alone. A prospective, randomized study validating these findings is now warranted.

  18. Does chlorhexidine and povidone-iodine preoperative antisepsis reduce surgical site infection in cranial neurosurgery?

    PubMed Central

    Davies, BM; Patel, HC

    2016-01-01

    Introduction Surgical site infection (SSI) is a significant cause of postoperative morbidity and mortality. Effective preoperative antisepsis is a recognised prophylactic, with commonly used agents including chlorhexidine (CHG) and povidone-iodine (PVI). However, there is emerging evidence to suggest an additional benefit when they are used in combination. Methods We analysed data from our prospective SSI database on patients undergoing clean cranial neurosurgery between October 2011 and April 2014. We compared the case-mix adjusted odds of developing a SSI in patients undergoing skin preparation with CGH or PVI alone or in combination. Results SSIs were detected in 2.6% of 1146 cases. Antisepsis with PVI alone was performed in 654 (57%) procedures, while 276 (24%) had CHG alone and 216 (19%) CHG and PVI together. SSIs were associated with longer operating time (p<0.001) and younger age (p=0.03). Surgery type (p<0.001) and length of operation (p<0.001) were significantly different between antisepsis groups. In a binary logistic regression model, CHG and PVI was associated with a significant reduction in the likelihood of developing an SSI (adjusted odds ratio [AOR] 0.12, 95% confidence interval [CI] 0.02–0.63) than either agent alone. There was no difference in SSI rates between CHG and PVI alone (AOR 0.60, 95% CI 0.24–1.5). Conclusions Combination skin preparation with CHG and PVI significantly reduced SSI rates compared to CHG or PVI alone. A prospective, randomized study validating these findings is now warranted. PMID:27055411

  19. The 2009 devaluation of radiosurgery and its impact on the neurosurgery-radiation oncology partnership.

    PubMed

    Heilbrun, M Peter; Adler, John R

    2010-07-01

    Neurosurgeons, radiation oncologists, and, increasingly, other surgical specialists recognize that radiosurgery is an important tool for managing selected disorders throughout the body. The partnership between neurosurgeons and radiation oncologists has resulted in collaborative studies that have established the clinical benefits of radiosurgery. Today, however, a range of political and financial issues is straining this relationship and thereby undermining the practice of radiosurgery. Neurosurgeons and radiation oncologists recently restricted the definition of radiosurgery to include only cranial- and spine-focused radiation treatments. Meanwhile, organized radiation oncology decided unilaterally that radiosurgery administered to other parts of the body would be termed stereotactic body radiation therapy. Finally, neurosurgical and radiation oncology coding experts developed new Current Procedural Terminology codes for cranial vault and spine radiosurgery, which were approved for use by the Relative Value Scale Update Committee as of 2009. The authors suggest that the neurosurgery strategy-which included 1) reasserting that all of the tasks of a radiosurgery procedure remain bundled, and 2) agreeing to limit the definition of radiosurgery to cranial vault and spine-has failed neurosurgeons who perform radiosurgery, and it may jeopardize patient access to this procedure in the future. The authors propose that all of the involved medical specialties recognize that the application of image-guided, focused radiation therapy throughout the body requires a partnership between radiation and surgical disciplines. They also urge surgeons to reexamine their coding methods, and they maintain that Current Procedural Terminology codes should be consistent across all of the different specialties involved in these procedures. Finally, surgeons should consider appropriate training in medical physics and radiobiology to perform the tasks involved in these specific procedures

  20. Graphical user interfaces for simulation of brain deformation in image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoyao; Ji, Songbai; Valdes, Pablo; Roberts, David W.; Hartov, Alex; Paulsen, Keith D.

    2010-02-01

    In image-guided neurosurgery, preoperative images are typically used for surgical planning and intraoperative guidance. The accuracy of preoperative images can be significantly compromised by intraoperative brain deformation. To compensate for brain shift, biomechanical finite element models have been used to assimilate intraoperative data to simulate brain deformation. The clinical feasibility of the approach strongly depends on its accuracy and efficiency. In order to facilitate and streamline data flow, we have developed graphical user interfaces (GUIs) to provide efficient image updates in the operating room (OR). The GUIs are organized in a top-down hierarchy with a main control panel that invokes and monitors a series of sub-GUIs dedicated to perform tasks involved in various aspects of computations of whole-brain deformation. These GUIs are used to segment brain, generate case-specific brain meshes, and assign and visualize case-specific boundary conditions (BC). Registration between intraoperative ultrasound (iUS) images acquired pre- and post-durotomy is also facilitated by a dedicated GUI to extract sparse displacement data used to drive a biomechanical model. Computed whole-brain deformation is then used to morph preoperative MR images (pMR) to generate a model-updated image set (i.e., uMR) for intraoperative guidance (accuracy of 1-2 mm). These task-driven GUIs have been designed to be fault-tolerant, user-friendly, and with sufficient automation. In this paper, we present the modular components of the GUIs and demonstrate the typical workflow through a clinical patient case.

  1. Financial and clinical governance implications of clinical coding accuracy in neurosurgery: a multidisciplinary audit.

    PubMed

    Haliasos, N; Rezajooi, K; O'neill, K S; Van Dellen, J; Hudovsky, Anita; Nouraei, Sar

    2010-04-01

    Clinical coding is the translation of documented clinical activities during an admission to a codified language. Healthcare Resource Groupings (HRGs) are derived from coding data and are used to calculate payment to hospitals in England, Wales and Scotland and to conduct national audit and benchmarking exercises. Coding is an error-prone process and an understanding of its accuracy within neurosurgery is critical for financial, organizational and clinical governance purposes. We undertook a multidisciplinary audit of neurosurgical clinical coding accuracy. Neurosurgeons trained in coding assessed the accuracy of 386 patient episodes. Where clinicians felt a coding error was present, the case was discussed with an experienced clinical coder. Concordance between the initial coder-only clinical coding and the final clinician-coder multidisciplinary coding was assessed. At least one coding error occurred in 71/386 patients (18.4%). There were 36 diagnosis and 93 procedure errors and in 40 cases, the initial HRG changed (10.4%). Financially, this translated to pound111 revenue-loss per patient episode and projected to pound171,452 of annual loss to the department. 85% of all coding errors were due to accumulation of coding changes that occurred only once in the whole data set. Neurosurgical clinical coding is error-prone. This is financially disadvantageous and with the coding data being the source of comparisons within and between departments, coding inaccuracies paint a distorted picture of departmental activity and subspecialism in audit and benchmarking. Clinical engagement improves accuracy and is encouraged within a clinical governance framework.

  2. Towards the development of a spring-based continuum robot for neurosurgery

    NASA Astrophysics Data System (ADS)

    Kim, Yeongjin; Cheng, Shing Shin; Desai, Jaydev P.

    2015-03-01

    Brain tumor is usually life threatening due to the uncontrolled growth of abnormal cells native to the brain or the spread of tumor cells from outside the central nervous system to the brain. The risks involved in carrying out surgery within such a complex organ can cause severe anxiety in cancer patients. However, neurosurgery, which remains one of the more effective ways of treating brain tumors focused in a confined volume, can have a tremendously increased success rate if the appropriate imaging modality is used for complete tumor removal. Magnetic resonance imaging (MRI) provides excellent soft-tissue contrast and is the imaging modality of choice for brain tumor imaging. MRI combined with continuum soft robotics has immense potential to be the revolutionary treatment technique in the field of brain cancer. It eliminates the concern of hand tremor and guarantees a more precise procedure. One of the prototypes of Minimally Invasive Neurosurgical Intracranial Robot (MINIR-II), which can be classified as a continuum soft robot, consists of a snake-like body made of three segments of rapid prototyped plastic springs. It provides improved dexterity with higher degrees of freedom and independent joint control. It is MRI-compatible, allowing surgeons to track and determine the real-time location of the robot relative to the brain tumor target. The robot was manufactured in a single piece using rapid prototyping technology at a low cost, allowing it to disposable after each use. MINIR-II has two DOFs at each segment with both joints controlled by two pairs of MRI-compatible SMA spring actuators. Preliminary motion tests have been carried out using vision-tracking method and the robot was able to move to different positions based on user commands.

  3. The impact of a patient education bundle on neurosurgery patient satisfaction

    PubMed Central

    Kliot, Tamara; Zygourakis, Corinna C.; Imershein, Sarah; Lau, Catherine; Kliot, Michel

    2015-01-01

    Background: As reimbursements and hospital/physician performance become ever more reliant on Hospital Consumer Assessment of Health Care Providers and Systems (HCAHPS) and other quality metrics, physicians are increasingly incentivized to improve patient satisfaction. Methods: A faculty and resident team at the University of California, San Francisco (UCSF) Department of Neurological Surgery developed and implemented a Patient Education Bundle. This consisted of two parts: The first was preoperative expectation letters (designed to inform patients of what to expect before, during, and after their hospitalization for a neurosurgical procedure); the second was a trifold brochure with names, photographs, and specialty/training information about the attending surgeons, resident physicians, and nurse practitioners on the neurosurgical service. We assessed patient satisfaction, as measured by HCAHPS scores and a brief survey tailored to our specific intervention, both before and after our Patient Education Bundle intervention. Results: Prior to our intervention, 74.6% of patients responded that the MD always explained information in a way that was easy to understand. After our intervention, 78.7% of patients responded that the MD always explained information in a way that was easy to understand. “Neurosurgery Patient Satisfaction survey” results showed that 83% remembered receiving the preoperative letter; of those received the letter, 93% found the letter helpful; and 100% thought that the letter should be continued. Conclusion: Although effects were modest, we believe that patient education strategies, as modeled in our bundle, can improve patients’ hospital experiences and have a positive impact on physician performance scores and hospital ratings. PMID:26664909

  4. Position statement from the Italian Society of Neurosurgery on the ARUBA Study.

    PubMed

    Cenzato, Marco; Delitala, Alberto; Delfini, Roberto; Pasqualin, Alberto; Maira, Giulio; Esposito, Vincenzo; Tomasello, Francesco; Boccardi, Edoardo

    2016-03-01

    As the conclusions of the ARUBA Study are strongly oriented towards therapeutic abstention, we think it is appropriate to express the concern of the Italian Society of Neurosurgery for the impact that this study might have on the health of patients, if not properly evaluated. The vast majority of patients (76-81%) included in the study was treated with endovascular or radiotherapy treatments, alone or in combination. Only 18 patients (19%) had surgery. It is well known that a partial treatment of arteriovenous malformations (AVMs), as is often the case with endovascular therapy, may increase the risk of bleeding. The primary endpoint (death or symptomatic stroke) in the treated group was reached in 30.7%, i.e. almost one-third of the subjects. This has no comparison in the current surgical literature. Considering permanent and transient neurological deficits along with headaches and seizures all together in the same outcome evaluation parameter may be inappropriate and misleading. The graph with all results from the ARUBA Study, which claims to be the demonstration that natural history is better that treatment, clearly shows that what is assumed to be treated has not actually been treated. If death or stroke occur a few years from treatment, it only means that the disease was not cured and patients received a partial - therefore ineffective, if not dangerous - treatment. An effective treatment, as surgery is, must have a flat follow-up curve. The ARUBA Study shows that incomplete treatment leads to negative outcome, confirming that an integrated multidisciplinary strategy has to be plotted out before starting any treatment and that a complete exclusion of the AVM must be achieved.

  5. Patient dose estimation from CT scans at the Mexican National Neurology and Neurosurgery Institute

    SciTech Connect

    Alva-Sánchez, Héctor

    2014-11-07

    In the radiology department of the Mexican National Institute of Neurology and Neurosurgery, a dedicated institute in Mexico City, on average 19.3 computed tomography (CT) examinations are performed daily on hospitalized patients for neurological disease diagnosis, control scans and follow-up imaging. The purpose of this work was to estimate the effective dose received by hospitalized patients who underwent a diagnostic CT scan using typical effective dose values for all CT types and to obtain the estimated effective dose distributions received by surgical and non-surgical patients. Effective patient doses were estimated from values per study type reported in the applications guide provided by the scanner manufacturer. This retrospective study included all hospitalized patients who underwent a diagnostic CT scan between 1 January 2011 and 31 December 2012. A total of 8777 CT scans were performed in this two-year period. Simple brain scan was the CT type performed the most (74.3%) followed by contrasted brain scan (6.1%) and head angiotomography (5.7%). The average number of CT scans per patient was 2.83; the average effective dose per patient was 7.9 mSv; the mean estimated radiation dose was significantly higher for surgical (9.1 mSv) than non-surgical patients (6.0 mSv). Three percent of the patients had 10 or more brain CT scans and exceeded the organ radiation dose threshold set by the International Commission on Radiological Protection for deterministic effects of the eye-lens. Although radiation patient doses from CT scans were in general relatively low, 187 patients received a high effective dose (>20 mSv) and 3% might develop cataract from cumulative doses to the eye lens.

  6. Retractor-induced brain shift compensation in image-guided neurosurgery

    NASA Astrophysics Data System (ADS)

    Fan, Xiaoyao; Ji, Songbai; Hartov, Alex; Roberts, David; Paulsen, Keith

    2013-03-01

    In image-guided neurosurgery, intraoperative brain shift significantly degrades the accuracy of neuronavigation that is solely based on preoperative magnetic resonance images (pMR). To compensate for brain deformation and to maintain the accuracy in image guidance achieved at the start of surgery, biomechanical models have been developed to simulate brain deformation and to produce model-updated MR images (uMR) to compensate for brain shift. To-date, most studies have focused on shift compensation at early stages of surgery (i.e., updated images are only produced after craniotomy and durotomy). Simulating surgical events at later stages such as retraction and tissue resection are, perhaps, clinically more relevant because of the typically much larger magnitudes of brain deformation. However, these surgical events are substantially more complex in nature, thereby posing significant challenges in model-based brain shift compensation strategies. In this study, we present results from an initial investigation to simulate retractor-induced brain deformation through a biomechanical finite element (FE) model where whole-brain deformation assimilated from intraoperative data was used produce uMR for improved accuracy in image guidance. Specifically, intensity-encoded 3D surface profiles at the exposed cortical area were reconstructed from intraoperative stereovision (iSV) images before and after tissue retraction. Retractor-induced surface displacements were then derived by coregistering the surfaces and served as sparse displacement data to drive the FE model. With one patient case, we show that our technique is able to produce uMR that agrees well with the reconstructed iSV surface after retraction. The computational cost to simulate retractor-induced brain deformation was approximately 10 min. In addition, our approach introduces minimal interruption to the surgical workflow, suggesting the potential for its clinical application.

  7. Slow angled-descent forepaw grasping (SLAG): an innate behavioral task for identification of individual experimental mice possessing functional vision

    PubMed Central

    2013-01-01

    Background There is significant interest in the generation of improved assays to clearly identify experimental mice possessing functional vision, a property that could qualify mice for inclusion in behavioral and neuroscience studies. Widely employed current methods rely on mouse responses to visual cues in assays of reflexes, depth perception, or cognitive memory. However, commonly assessed mouse reflexes can sometimes be ambiguous in their expression, while depth perception assays are sometimes confounded by variation in anxiety responses and exploratory conduct. Furthermore, in situations where experimental groups vary in their cognitive memory capacity, memory assays may not be ideal for assessing differences in vision. Results We have optimized a non-invasive behavioral assay that relies on an untrained, innate response to identify individual experimental mice possessing functional vision: slow angled-descent forepaw grasping (SLAG). First, we verified that SLAG performance depends on vision and not olfaction. Next, all members of an age-ranged cohort of 158 C57BL/6 mice (57 wild-type, 101 knockout, age range 44–241 days) were assessed for functional vision using the SLAG test without training or conditioning. Subjecting the population to a second innate behavioral test, Dark Chamber preference, corroborated that the functional vision assessment of SLAG was valid. Conclusions We propose that the SLAG assay is immediately useful to quickly and clearly identify experimental mice possessing functional vision. SLAG is based on a behavioral readout with a significant innate component with no requirement for training. This will facilitate the selection of mice of known sighted status in vision-dependent experiments that focus on other types of behavior, neuroscience, and/or cognitive memory. PMID:23971729

  8. A comparative cost analysis of polytrauma and neurosurgery Intensive Care Units at an apex trauma care facility in India

    PubMed Central

    Kumar, Parmeshwar; Jithesh, V.; Gupta, Shakti Kumar

    2016-01-01

    Context: Although Intensive Care Units (ICUs) only account for 10% of the hospital beds, they consume nearly 22% of the hospital resources. Few definitive costing studies have been conducted in Indian settings that would help determine appropriate resource allocation. Aim: The aim of this study was to evaluate and compare the cost of intensive care delivery between multispecialty and neurosurgery ICUs at an apex trauma care facility in India. Materials and Methods: The study was conducted in a polytrauma and neurosurgery ICU at a 203-bedded Level IV trauma care facility in New Delhi, India, from May 1, 2012 to June 30, 2012. The study was cross-sectional, retrospective, and record-based. Traditional costing was used to arrive at the cost for both direct and indirect cost estimates. The cost centers included in the study were building cost, equipment cost, human resources, materials and supplies, clinical and nonclinical support services, engineering maintenance cost, and biomedical waste management. Statistical Analysis: Statistical analysis was performed by Fisher's two tailed t-test. Results: Total cost/bed/day for the multispecialty ICU was Rs. 14,976.9/- and for the neurosurgery ICU, it was Rs. 14,306.7/-, workforce constituting nearly half of the expenditure in both ICUs. The cost center wise and overall difference in the cost among the ICUs were statistically significant. Conclusions: Quantification of expenditure in running an ICU in a trauma center would assist health-care decision makers in better allocation of resources. Although multispecialty ICUs are more cost-effective, other factors will also play a role in defining the kind of ICU that needs to be designed. PMID:27555693

  9. First Experiences in Intensity Modulated Radiation Surgery at the National Institute of Neurology and Neurosurgery: A Dosimetric Point of View

    NASA Astrophysics Data System (ADS)

    Lárraga-Gutiérrez, José M.; Celis-López, Miguel A.

    2003-09-01

    The National Institute of Neurology and Neurosurgery in Mexico City has acquired a Novalis® shaped beam radiosurgery unit. The institute is pioneer in the use of new technologies for neuroscience. The Novalis® unit allows the use of conformal beam radiosurgery/therapy and the more advanced modality of conformal therapy: Intensity Modulated Radiation Therapy (IMRT). In the present work we present the first cases of treatments that use the IMRT technique and show its ability to protect organs at risk, such as brainstem and optical vias.

  10. Functional rescue of experimental ischemic optic neuropathy with αB-crystallin

    PubMed Central

    Pangratz-Fuehrer, S; Kaur, K; Ousman, S S; Steinman, L; Liao, Y J

    2011-01-01

    Purpose Anterior ischemic optic neuropathy (AION) is an important cause of acute vision loss in adults, and there is no effective treatment. We studied early changes following experimental AION and tested the benefit of a potential treatment. Materials and Methods We induced experimental AION in adult mice and tested the effects of short-term (daily for 3 days) and long-term (every other day for 3 weeks) αB-crystallin (αBC) treatment using histological and serial intracranial flash visual evoked potential recordings. Results One day after experimental AION, there was swelling at the optic nerve (ON) head and increased expression of αBC, a small heat shock protein important in ischemia and inflammation. This upregulation coincided with microglial and astrocytic activation. Our hypothesis was that αBC may be part of the endogenous protective mechanism against injury, thus we tested the effects of αBC on experimental AION. Daily intraveneous or intravitreal αBC injections did not improve visual evoked potential amplitude or latency at days 1–2. However, αBC treatment decreased swelling and dampened the microglial and astrocytic activation on day 3. Longer treatment with intravenous αBC led to acceleration of visual evoked potential latency over 3 weeks, without improving amplitude. This latency acceleration did not correlate with increased retinal ganglion cell survival but did correlate with complete rescue of the ON oligodendrocytes, which are important for myelination. Conclusions We identified αBC as an early marker following experimental AION. Treatment with αBC enhanced this endogenous, post-ischemic response by decreasing microglial activation and promoting ON oligodendrocyte survival. PMID:21475310

  11. The Functions of Self-Injurious Behavior: An Experimental-Epidemiological Analysis.

    ERIC Educational Resources Information Center

    Iwata, Brian A.; And Others

    1994-01-01

    Data are summarized from 152 single-subject analyses of the reinforcing functions of self-injurious behavior (SIB) in individuals with developmental disabilities. Overall results indicated that functional analysis methodologies are extremely effective in identifying the environmental determinants of SIB on an individual basis and, subsequently, in…

  12. Current Approaches to Quantifying Tonic and Reflex Autonomic Outflows Controlling Cardiovascular Function in Humans and Experimental Animals.

    PubMed

    Salman, Ibrahim M

    2015-11-01

    The role of the autonomic nervous system in the pathophysiology of human and experimental models of cardiovascular disease is well established. In the recent years, there have been some rapid developments in the diagnostic approaches used to assess and monitor autonomic functions. Although most of these methods are devoted for research purposes in laboratory animals, many have still found their way to routine clinical practice. To name a few, direct long-term telemetry recording of sympathetic nerve activity (SNA) in rodents, single-unit SNA recording using microneurography in human subjects and spectral analysis of blood pressure and heart rate in both humans and animals have recently received an overwhelming attention. In this article, we therefore provide an overview of the methods and techniques used to assess tonic and reflex autonomic functions in humans and experimental animals, highlighting current advances available and procedure description, limitations and usefulness for diagnostic purposes.

  13. CT10 NLO and NNLO Parton Distribution Functions from the Coordinated Theoretical-Experimental Project on QCD

    DOE Data Explorer

    Huston, Joey [Co-Spokesperson; Ownes, Joseph [Co-Spokesperson

    The Coordinated Theoretical-Experimental Project on QCD is a multi-institutional collaboration devoted to a broad program of research projects and cooperative enterprises in high-energy physics centered on Quantum Chromodynamics (QCD) and its implications in all areas of the Standard Model and beyond. The Collaboration consists of theorists and experimentalists at 18 universities and 5 national laboratories. More than 65 sets of Parton Distribution Functions are available for public access. Links to many online software tools, information about Parton Distribution Functions, papers, and other resources are also available.

  14. The Synthesis of Structural Responses Using Experimentally Measured Frequency Response Functions and Field Test Data

    SciTech Connect

    CAP,JEROME S.; NELSON,CURTIS F.

    2000-11-17

    This paper presents an analysis technique used to generate the structural response at locations not measured during the ejection of a captive-carried store. The ejection shock event is complicated by the fact that forces may be imparted to the store at eight distinct locations. The technique derives forcing functions by combining the initial field test data for a limited number of measurement locations with Frequency Response Functions (FRFs) measured using a traditional modal-type impact (tap) test at the same locations. The derived forcing functions were then used with tap test FRFs measured at additional locations of interest to produce the desired response data.

  15. Experimental support for the foldability–function tradeoff hypothesis: Segregation of the folding nucleus and functional regions in fibroblast growth factor-1

    PubMed Central

    Longo, Liam; Lee, Jihun; Blaber, Michael

    2012-01-01

    The acquisition of function is often associated with destabilizing mutations, giving rise to the stability–function tradeoff hypothesis. To test whether function is also accommodated at the expense of foldability, fibroblast growth factor-1 (FGF-1) was subjected to a comprehensive φ-value analysis at each of the 11 turn regions. FGF-1, a β-trefoil fold, represents an excellent model system with which to evaluate the influence of function on foldability: because of its threefold symmetric structure, analysis of FGF-1 allows for direct comparisons between symmetry-related regions of the protein that are associated with function to those that are not; thus, a structural basis for regions of foldability can potentially be identified. The resulting φ-value distribution of FGF-1 is highly polarized, with the majority of positions described as either folded-like or denatured-like in the folding transition state. Regions important for folding are shown to be asymmetrically distributed within the protein architecture; furthermore, regions associated with function (i.e., heparin-binding affinity and receptor-binding affinity) are localized to regions of the protein that fold after barrier crossing (late in the folding pathway). These results provide experimental support for the foldability–function tradeoff hypothesis in the evolution of FGF-1. Notably, the results identify the potential for folding redundancy in symmetric protein architecture with important implications for protein evolution and design. PMID:23047594

  16. Polynomial dual energy inverse functions for bone Calcium/Phosphorus ratio determination and experimental evaluation.

    PubMed

    Sotiropoulou, P; Fountos, G; Martini, N; Koukou, V; Michail, C; Kandarakis, I; Nikiforidis, G

    2016-12-01

    An X-ray dual energy (XRDE) method was examined, using polynomial nonlinear approximation of inverse functions for the determination of the bone Calcium-to-Phosphorus (Ca/P) mass ratio. Inverse fitting functions with the least-squares estimation were used, to determine calcium and phosphate thicknesses. The method was verified by measuring test bone phantoms with a dedicated dual energy system and compared with previously published dual energy data. The accuracy in the determination of the calcium and phosphate thicknesses improved with the polynomial nonlinear inverse function method, introduced in this work, (ranged from 1.4% to 6.2%), compared to the corresponding linear inverse function method (ranged from 1.4% to 19.5%).

  17. Effects of Plant Diversity, Functional Group Composition, and Fertilization on Soil Microbial Properties in Experimental Grassland

    PubMed Central

    Strecker, Tanja; Barnard, Romain L.; Niklaus, Pascal A.; Scherer-Lorenzen, Michael; Weigelt, Alexandra; Scheu, Stefan; Eisenhauer, Nico

    2015-01-01

    Background Loss of biodiversity and increased nutrient inputs are two of the most crucial anthropogenic factors driving ecosystem change. Although both received considerable attention in previous studies, information on their interactive effects on ecosystem functioning is scarce. In particular, little is known on how soil biota and their functions are affected by combined changes in plant diversity and fertilization. Methodology/Principal Findings We investigated the effects of plant diversity, functional community composition, and fertilization on the biomass and respiration of soil microbial communities in a long-term biodiversity experiment in semi-natural grassland (Jena Experiment). Plant species richness enhanced microbial basal respiration and microbial biomass, but did not significantly affect microbial specific respiration. In contrast, the presence of legumes and fertilization significantly decreased microbial specific respiration, without altering microbial biomass. The effect of legumes was superimposed by fertilization as indicated by a significant interaction between the presence of legumes and fertilization. Further, changes in microbial stoichiometry (C-to-N ratio) and specific respiration suggest the presence of legumes to reduce N limitation of soil microorganisms and to modify microbial C use efficiency. Conclusions/Significance Our study highlights the role of plant species and functional group diversity as well as interactions between plant community composition and fertilizer application for soil microbial functions. Our results suggest soil microbial stoichiometry to be a powerful indicator of microbial functioning under N limited conditions. Although our results support the notion that plant diversity and fertilizer application independently affect microbial functioning, legume effects on microbial N limitation were superimposed by fertilization, indicating significant interactions between the functional composition of plant communities and

  18. The Krigifier: A Procedure for Generating Pseudorandom Nonlinear Objective Functions for Computational Experimentation

    NASA Technical Reports Server (NTRS)

    Trosset, Michael W.

    1999-01-01

    Comprehensive computational experiments to assess the performance of algorithms for numerical optimization require (among other things) a practical procedure for generating pseudorandom nonlinear objective functions. We propose a procedure that is based on the convenient fiction that objective functions are realizations of stochastic processes. This report details the calculations necessary to implement our procedure for the case of certain stationary Gaussian processes and presents a specific implementation in the statistical programming language S-PLUS.

  19. Functional Analysis and Discovery of Microbial Genes Transforming Metallic and Organic Pollutants: Database and Experimental Tools

    SciTech Connect

    Lawrence P. Wackett; Lynda B.M. Ellis

    2004-12-09

    Microbial functional genomics is faced with a burgeoning list of genes which are denoted as unknown or hypothetical for lack of any knowledge about their function. The majority of microbial genes encode enzymes. Enzymes are the catalysts of metabolism; catabolism, anabolism, stress responses, and many other cell functions. A major problem facing microbial functional genomics is proposed here to derive from the breadth of microbial metabolism, much of which remains undiscovered. The breadth of microbial metabolism has been surveyed by the PIs and represented according to reaction types on the University of Minnesota Biocatalysis/Biodegradation Database (UM-BBD): http://umbbd.ahc.umn.edu/search/FuncGrps.html The database depicts metabolism of 49 chemical functional groups, representing most of current knowledge. Twice that number of chemical groups are proposed here to be metabolized by microbes. Thus, at least 50% of the unique biochemical reactions catalyzed by microbes remain undiscovered. This further suggests that many unknown and hypothetical genes encode functions yet undiscovered. This gap will be partly filled by the current proposal. The UM-BBD will be greatly expanded as a resource for microbial functional genomics. Computational methods will be developed to predict microbial metabolism which is not yet discovered. Moreover, a concentrated effort to discover new microbial metabolism will be conducted. The research will focus on metabolism of direct interest to DOE, dealing with the transformation of metals, metalloids, organometallics and toxic organics. This is precisely the type of metabolism which has been characterized most poorly to date. Moreover, these studies will directly impact functional genomic analysis of DOE-relevant genomes.

  20. Automated genomic context analysis and experimental validation platform for discovery of prokaryote transcriptional regulator functions

    DOE PAGES

    Martí-Arbona, Ricardo; Mu, Fangping; Nowak-Lovato, Kristy L.; ...

    2014-12-18

    The clustering of genes in a pathway and the co-location of functionally related genes is widely recognized in prokaryotes. We used these characteristics to predict the metabolic involvement for a Transcriptional Regulator (TR) of unknown function, identified and confirmed its biological activity. A software tool that identifies the genes encoded within a defined genomic neighborhood for the subject TR and its homologs was developed. The output lists of genes in the genetic neighborhoods, their annotated functions, the reactants/products, and identifies the metabolic pathway in which the encoded-proteins function. When a set of TRs of known function was analyzed, we observedmore » that their homologs frequently had conserved genomic neighborhoods that co-located the metabolically related genes regulated by the subject TR. We postulate that TR effectors are metabolites in the identified pathways; indeed the known effectors were present. We analyzed Bxe_B3018 from Burkholderia xenovorans, a TR of unknown function and predicted that this TR was related to the glycine, threonine and serine degradation. We tested the binding of metabolites in these pathways and for those that bound, their ability to modulate TR binding to its specific DNA operator sequence. Using rtPCR, we confirmed that methylglyoxal was an effector of Bxe_3018.« less

  1. Automated genomic context analysis and experimental validation platform for discovery of prokaryote transcriptional regulator functions

    SciTech Connect

    Martí-Arbona, Ricardo; Mu, Fangping; Nowak-Lovato, Kristy L.; Wren, Melinda S.; Unkefer, Clifford J.; Unkefer, Pat J.

    2014-12-18

    The clustering of genes in a pathway and the co-location of functionally related genes is widely recognized in prokaryotes. We used these characteristics to predict the metabolic involvement for a Transcriptional Regulator (TR) of unknown function, identified and confirmed its biological activity. A software tool that identifies the genes encoded within a defined genomic neighborhood for the subject TR and its homologs was developed. The output lists of genes in the genetic neighborhoods, their annotated functions, the reactants/products, and identifies the metabolic pathway in which the encoded-proteins function. When a set of TRs of known function was analyzed, we observed that their homologs frequently had conserved genomic neighborhoods that co-located the metabolically related genes regulated by the subject TR. We postulate that TR effectors are metabolites in the identified pathways; indeed the known effectors were present. We analyzed Bxe_B3018 from Burkholderia xenovorans, a TR of unknown function and predicted that this TR was related to the glycine, threonine and serine degradation. We tested the binding of metabolites in these pathways and for those that bound, their ability to modulate TR binding to its specific DNA operator sequence. Using rtPCR, we confirmed that methylglyoxal was an effector of Bxe_3018.

  2. GSNO promotes functional recovery in experimental TBI by stabilizing HIF-1α.

    PubMed

    Khan, Mushfiquddin; Dhammu, Tajinder S; Baarine, Mauhamad; Kim, Jinsu; Paintlia, Manjeet K; Singh, Inderjit; Singh, Avtar K

    2016-10-22

    Traumatic brain injury (TBI) causes sustained disability due to compromised neurorepair mechanisms. Crucial to neurorepair and functional recovery following both TBI and stroke is hypoxia-inducible factor-1 alpha (HIF-1α). Based on reports that HIF-1α could be stabilized via S-nitrosylation, we tested the hypothesis that the S-nitrosylating agent S-nitrosoglutathione (GSNO) would stabilize HIF-1α, thereby stimulating neurorepair mechanisms and aiding in functional recovery. TBI was induced by controlled cortical impact (CCI) in adult rats. GSNO (0.05mg/kg) was administered at two hours after CCI. The treatment was repeated daily until the 14th day after CCI. Functional recovery was assessed by motor and cognitive functions, and the recovery was compared with the expression of HIF-1α. The mechanisms of GSNO-mediated S-nitrosylation of HIF-1α were determined using brain endothelial cells. While non-treated TBI animals showed sustained neurobehavioral deficits, GSNO treatment of TBI improved neurobehavioral functions. GSNO also increased the expression of HIF-1α and VEGF. The beneficial effects of GSNO on neurobehavioral functions in TBI animals were blocked by treatment with the HIF-1α inhibitor 2-methoxyestradiol (2-ME). The stimulatory effect of GSNO on VEGF was reversed not only by 2-ME but also by the denitrosylating agent dithiothreitol, confirming our hypothesis that GSNO's benefits are mediated by the stabilization of HIF-1α via S-nitrosylation. GSNO's S-nitrosylation of HIF-1α was further confirmed using a biotin switch assay in endothelial cells. The data provide evidence that GSNO treatment of TBI aids functional recovery through stabilizing HIF-1α via S-nitrosylation. GSNO is a natural component of the human brain/body, and its exogenous administration has not shown adverse effects in humans. Therefore, the translational potential of GSNO therapy in TBI is high.

  3. Polyamino acid functionalized membranes for metal capture and nanofiltration of organics: Modeling and experimental verification

    NASA Astrophysics Data System (ADS)

    Hestekin, Jamie Allen

    2000-10-01

    Passive membranes have been used for separations ranging from seawater desalination via reverse osmosis to the separation of particles with microfiltration membranes. However the attachment of macromolecules, with multiple functional sites, to microfiltration membranes allows for more selective separations. For these reasons, we have designed a novel membrane system, consisting of cellulose-based microfiltration membranes functionalized with polyamino acids (2,500--15,000 MW). Because of the high carboxyl content of the polyamino acids, these membranes have been shown to be extremely useful for the separation of heavy metals from aqueous solutions. The primary objective of this research was to establish the sorption mechanisms of functionalized microfiltration membranes and use these mechanisms to predict the rate behavior of metal transport through these membranes. Both cellulose acetate and pure cellulose were used as membrane support materials. Extensive experiments (pH 3--6) were conducted (under convective flow mode) with the derivatized membranes involving the heavy metals: lead, cadmium, nickel, copper, and selected mixtures with calcium in aqueous solutions. Metal sorption results were found to be a function of derivatization (aldehydes) density of membranes and degree of attachment of the polyfunctional groups, number of functional groups per chain, membrane surface area, and the type of metals to be sorbed. We have obtained metal sorption capacities as high as 1.5 g metal/g membrane. As opposed to homogeneous solution systems, the molar sorption capacities of the functional carboxyl sites are significantly enhanced in the membrane pores because of counterion condensation resulting partly from the extremely high charge densities in the membrane pores. This phenomenon was incorporated in a kinetic model for the prediction of sorption behavior. The model studied the effect of pore size, polyamino acid attachment density, pH, and metal type. Finally, in

  4. Experimental and theoretical investigations of functionalized boron nitride as electrode materials for Li-ion batteries

    SciTech Connect

    Zhang, Fan; Nemeth, Karoly; Bareno, Javier; Dogan, Fulya; Bloom, Ira D.; Shaw, Leon L.

    2016-03-03

    The feasibility of synthesizing functionalized h-BN (FBN) via the reaction between molten LiOH and solid h-BN is studied for the first time and its first ever application as an electrode material in Li-ion batteries is evaluated. Density functional theory (DFT) calculations are performed to provide mechanistic understanding of the possible electrochemical reactions derived from the FBN. Various materials characterizations reveal that the melt-solid reaction can lead to exfoliation and functionalization of h-BN simultaneously, while electrochemical analysis proves that the FBN can reversibly store charges through surface redox reactions with good cycle stability and coulombic efficiency. As a result, the DFT calculations have provided physical insights into the observed electrochemical properties derived from the FBN.

  5. Experimental and theoretical investigations of functionalized boron nitride as electrode materials for Li-ion batteries

    DOE PAGES

    Zhang, Fan; Nemeth, Karoly; Bareno, Javier; ...

    2016-03-03

    The feasibility of synthesizing functionalized h-BN (FBN) via the reaction between molten LiOH and solid h-BN is studied for the first time and its first ever application as an electrode material in Li-ion batteries is evaluated. Density functional theory (DFT) calculations are performed to provide mechanistic understanding of the possible electrochemical reactions derived from the FBN. Various materials characterizations reveal that the melt-solid reaction can lead to exfoliation and functionalization of h-BN simultaneously, while electrochemical analysis proves that the FBN can reversibly store charges through surface redox reactions with good cycle stability and coulombic efficiency. As a result, the DFTmore » calculations have provided physical insights into the observed electrochemical properties derived from the FBN.« less

  6. Experimental evolution, loss-of-function mutations, and "the first rule of adaptive evolution".

    PubMed

    Behe, Michael J

    2010-12-01

    Adaptive evolution can cause a species to gain, lose, or modify a function; therefore, it is of basic interest to determine whether any of these modes dominates the evolutionary process under particular circumstances. Because mutation occurs at the molecular level, it is necessary to examine the molecular changes produced by the underlying mutation in order to assess whether a given adaptation is best considered as a gain, loss, or modification of function. Although that was once impossible, the advance of molecular biology in the past half century has made it feasible. In this paper, I review molecular changes underlying some adaptations, with a particular emphasis on evolutionary experiments with microbes conducted over the past four decades. I show that by far the most common adaptive changes seen in those examples are due to the loss or modification of a pre-existing molecular function, and I discuss the possible reasons for the prominence of such mutations.

  7. Cardiac autonomic denervation and functional response to neurotoxins during acute experimental Chagas' disease in rats.

    PubMed

    Teixeira, A L; Fontoura, B F; Freire-Maia, L; Chiari, E; Machado, C R; Teixeira, M M; Camargos, E R

    2001-06-20

    Severe cardiac autonomic denervation occurs in the acute Chagas' disease in rats. The present study aims at verifying whether this denervation was accompanied by impairment of heart function. Scorpionic (Tityus serrulatus) crude venom was used for neurotransmitter release in isolated hearts (Langendorff's preparation). In control hearts, the venom induced significant bradycardia followed by tachycardia. In infected animals, despite the severe (sympathetic) or moderate (parasympathetic) cardiac denervation, the venom provoked similar bradycardia but the tachycardia was higher. The hearts of infected animals beat at significantly lower rate. Atropine prevented this lower rate. Our results demonstrated sympathetic dysfunction during the acute phase of Trypanosoma cruzi infection in rats, the parasympathetic function being spared.

  8. Electronic and optical response of Ru(II) complexes functionalized by methyl, carboxylate groups: joint theoretical and experimental study

    SciTech Connect

    Tretiak, Sergei

    2008-01-01

    New photovoltaic and photocatalysis applications have been recently proposed based on the hybrid Ru(II)-bipyridine-complex/semiconductor quantum dot systems. In order to attach the complex to the surface of a semiconductor, a linking bridge - a carboxyl group - is added to one or two of the 2,2{prime}-bipyridine ligands. Such changes in the ligand structure, indeed, affect electronic and optical properties and consequently, the charge transfer reactivity of Ru-systems. In this study, we apply both theoretical and experimental approaches to analyze the effects brought by functionalization of bipyridine ligands with the methyl, carboxyl, and carboxilate groups on the electronic structure and optical response of the Ru(II) bipyridine complex. First principle calculations based on density functional theory (DFT) and linear response time dependent density functional theory (TDDFT) are used to simulate the ground and excited-state structures of functionalized Ru-complexes in the gas phase, as well as in acetonitrile solution. In addition, an inelaborate Frenkel exciton model is used to explain the optical activity and splitting patterns of the low-energy excited states. All theoretical results nicely complement experimental absorption spectra of Ru-complexes and contribute to their interpretation. We found that the carboxyl group breaks the degeneracy of two low-energy optically bright excited states and red-shifts the absorption spectrum, while leaves ionization and affinity energies of complexes almost unchanged. Experimental studies show a high probability of deprotonation of the carbboxyl group in the Ru-complexes resulted in a slight blue shift and decrease of intensities of the low energy absorption peaks. Comparison of experimental and theoretical linear response spectra of deprotanated complexes demonstrate strong agreement when acetonitrile solvent is used in simulations. A polar solvent is found to play an important role in calculations of optical spectra: it

  9. Experimental and Theoretical Investigations of Phonation Threshold Pressure as a Function of Vocal Fold Elongation

    PubMed Central

    Tao, Chao; Regner, Michael F.; Zhang, Yu; Jiang, Jack J.

    2014-01-01

    Summary The relationship between the vocal fold elongation and the phonation threshold pressure (PTP) was experimentally and theoretically investigated. The PTP values of seventeen excised canine larynges with 0% to 15% bilateral vocal fold elongations in 5% elongation steps were measured using an excised larynx phonation system. It was found that twelve larynges exhibited a monotonic relationship between PTP and elongation; in these larynges, the 0% elongation condition had the lowest PTP. Five larynges exhibited a PTP minimum at 5% elongation. To provide a theoretical explanation of these phenomena, a two-mass model was modified to simulate vibration of the elongated vocal folds. Two pairs of longitudinal springs were used to represent the longitudinal elastin in the vocal folds. This model showed that when the vocal folds were elongated, the increased longitudinal tension would increase the PTP value and the increased vocal fold length would decrease the PTP value. The antagonistic effects contributed by these two factors were found to be able to cause either a monotonic or a non-monotonic relationship between PTP and elongation, which were consistent with experimental observations. Because PTP describes the ease of phonation, this study suggests that there may exist a nonzero optimal vocal fold elongation for the greatest ease for phonation in some larynges. PMID:25530744

  10. Experimental studies of mitochondrial function in CADASIL vascular smooth muscle cells.

    PubMed

    Viitanen, Matti; Sundström, Erik; Baumann, Marc; Poyhonen, Minna; Tikka, Saara; Behbahani, Homira

    2013-02-01

    Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a familiar fatal progressive degenerative disorder characterized by cognitive decline, and recurrent stroke in young adults. Pathological features include a dramatic reduction of brain vascular smooth muscle cells and severe arteriopathy with the presence of granular osmophilic material in the arterial walls. Here we have investigated the cellular and mitochondrial function in vascular smooth muscle cell lines (VSMCs) established from CADASIL mutation carriers (R133C) and healthy controls. We found significantly lower proliferation rates in CADASIL VSMC as compared to VSMC from controls. Cultured CADASIL VSMCs were not more vulnerable than control cells to a number of toxic substances. Morphological studies showed reduced mitochondrial connectivity and increased number of mitochondria in CADASIL VSMCs. Transmission electron microscopy analysis demonstrated increased irregular and abnormal mitochondria in CADASIL VSMCs. Measurements of mitochondrial membrane potential (Δψ(m)) showed a lower percentage of fully functional mitochondria in CADASIL VSMCs. For a number of genes previously reported to be changed in CADASIL VSMCs, immunoblotting analysis demonstrated a significantly reduced SOD1 expression. These findings suggest that alteration of proliferation and mitochondrial function in CADASIL VSMCs might have an effect on vital cellular functions important for CADASIL pathology.

  11. Cardiac Function Remains Impaired Despite Reversible Cardiac Remodeling after Acute Experimental Viral Myocarditis

    PubMed Central

    Gotzhein, Frauke; Escher, Felicitas; Blankenberg, Stefan; Westermann, Dirk

    2017-01-01

    Background. Infection with Coxsackievirus B3 induces myocarditis. We aimed to compare the acute and chronic phases of viral myocarditis to identify the immediate effects of cardiac inflammation as well as the long-term effects after resolved inflammation on cardiac fibrosis and consequently on cardiac function. Material and Methods. We infected C57BL/6J mice with Coxsackievirus B3 and determined the hemodynamic function 7 as well as 28 days after infection. Subsequently, we analyzed viral burden and viral replication in the cardiac tissue as well as the expression of cytokines and matrix proteins. Furthermore, cardiac fibroblasts were infected with virus to investigate if viral infection alone induces profibrotic signaling. Results. Severe cardiac inflammation was determined and cardiac fibrosis was consistently colocalized with inflammation during the acute phase of myocarditis. Declined cardiac inflammation but no significantly improved hemodynamic function was observed 28 days after infection. Interestingly, cardiac fibrosis declined to basal levels as well. Both cardiac inflammation and fibrosis were reversible, whereas the hemodynamic function remains impaired after healed viral myocarditis in C57BL/6J mice. PMID:28352641

  12. Experimental functional analysis of severe skin-picking behavior in Prader-Willi syndrome.

    PubMed

    Hall, Scott S; Hustyi, Kristin M; Chui, Clara; Hammond, Jennifer L

    2014-10-01

    Skin picking is an extremely distressing and treatment resistant behavior commonly shown by individuals with Prader-Willi syndrome (PWS). However, with the exception of a limited number of published single-case and survey studies, little is known about the environmental determinants of skin picking in this population. In this study, functional analyses were conducted with thirteen individuals with PWS, aged 6-23 years, who engaged in severe skin-picking behavior. In addition to the conditions typically employed in a functional analysis (i.e., alone, attention, play, demand), we included an ignore condition to examine potential effects of stimulus control by the presence of an adult. Twelve participants engaged in skin picking during the functional analysis, with the highest levels occurring in the alone and ignore conditions for eight participants, suggesting that skin picking in these participants was maintained by automatic reinforcement. For the remaining four participants, an undifferentiated pattern of low-rate skin picking was observed across conditions. These data confirm previous studies indicating that skin picking in PWS may be maintained most often by automatically produced sensory consequences. There were no associations between demographic characteristics of the participants (e.g., sex, age, IQ or BMI) and levels of skin picking observed in the functional analysis. Additional investigations are needed to identify the nature of the sensory consequences produced during episodes of skin picking in PWS. Behavioral interventions designed to extinguish or compete with the potential sensory consequences arising from skin picking in PWS are also warranted.

  13. Preparation of Problem Oriented Learning Materials: Experimental Project: Farmers Functional Literacy Programme.

    ERIC Educational Resources Information Center

    Deleon, Asher, Ed.

    Using practical problems faced by farmers developing new agricultural methods, a problem-oriented approach to adult functional literacy was developed and tested in the Jaipur district. The booklet explains the first two of the project's five phases: exploration, syllabus and curriculum construction, materials preparation, action, and evaluation.…

  14. Experimental Analysis of Preschool Playmate Preferences as a Function of Smiles and Sex

    ERIC Educational Resources Information Center

    Schultz, David; Ambike, Archana; Buckingham-Howes, Stacy; Cheah, Charissa S. L.

    2008-01-01

    Differential emotions theory (DET) ("The face of emotion." Appleton-Century-Crofts: East Norwalk, CT, 1971) posits that the smile functions in part to communicate and/or reflect social affiliation and plays an important role in children's social development. While children's positive emotion expressions have received attention from peer relations…

  15. Diffusion Tensor Imaging as a Predictor of Locomotor Function after Experimental Spinal Cord Injury and Recovery

    PubMed Central

    Kelley, Brian J.; Harel, Noam Y.; Kim, Chang-Yeon; Papademetris, Xenophon; Coman, Daniel; Wang, Xingxing; Hasan, Omar; Kaufman, Adam; Globinsky, Ronen; Staib, Lawrence H.; Cafferty, William B.J.; Hyder, Fahmeed

    2014-01-01

    Abstract Traumatic spinal cord injury (SCI) causes long-term disability with limited functional recovery linked to the extent of axonal connectivity. Quantitative diffusion tensor imaging (DTI) of axonal integrity has been suggested as a potential biomarker for prognostic and therapeutic evaluation after trauma, but its correlation with functional outcomes has not been clearly defined. To examine this application, female Sprague-Dawley rats underwent midthoracic laminectomy followed by traumatic spinal cord contusion of differing severities or laminectomy without contusion. Locomotor scores and hindlimb kinematic data were collected for 4 weeks post-injury. Ex vivo DTI was then performed to assess axonal integrity using tractography and fractional anisotropy (FA), a numerical measure of relative white matter integrity, at the injury epicenter and at specific intervals rostral and caudal to the injury site. Immunohistochemistry for tissue sparing was also performed. Statistical correlation between imaging data and functional performance was assessed as the primary outcome. All injured animals showed some recovery of locomotor function, while hindlimb kinematics revealed graded deficits consistent with injury severity. Standard T2 magnetic resonance sequences illustrated conventional spinal cord morphology adjacent to contusions while corresponding FA maps indicated graded white matter pathology within these adjacent regions. Positive correlations between locomotor (Basso, Beattie, and Bresnahan score and gait kinematics) and imaging (FA values) parameters were also observed within these adjacent regions, most strongly within caudal segments beyond the lesion. Evaluation of axonal injury by DTI provides a mechanism for functional recovery assessment in a rodent SCI model. These findings suggest that focused DTI analysis of caudal spinal cord should be studied in human cases in relationship to motor outcome to augment outcome biomarkers for clinical cases. PMID

  16. A curious experiment: the paradigm switch from observation and speculation to experimentation, in the understanding of neuromuscular function and disease.

    PubMed

    Pearn, John

    2002-08-01

    The four-link chain of the motor unit represents the contemporary end-point of some two millennia of evolving knowledge in neuroscience. The paradigm shift in neuromuscular epistemology occurred in the mid-17th century. In 1666, the newly graduated Dutch doctor, Jan Swammerdam (1637-1680) published his former investigations of dissected nerve-muscle preparations. These experiments comprised the quantum leap from observation and speculation, to that of experimentation in the field of neuroanatomy and neurophysiology. In what he termed 'A Curious Experiment' he also described the phenomenon of intrinsic muscle excitability - "I cannot observe that the muscle in the living animal ever absolutely ceases from all motion". Eighty years later (1752), von Haller demonstrated experimentally that irritability (contractility) was an intrinsic property of all muscular tissue; and distinguished between the sensibility of nerve impulses and the irritability of muscular contraction. This experimental progression from Swammerdam to von Haller culminated in 1850, when Claude Bernard's studies in experimental pharmacology confirmed that muscle was a functional unit, independent of any electrical innervation via its supplying nerve. This account comprises an audit of Swammerdam's work in the perspective of neuromuscular knowledge.

  17. Deuteron induced reactions on Ho and La: Experimental excitation functions and comparison with code results

    NASA Astrophysics Data System (ADS)

    Hermanne, A.; Adam-Rebeles, R.; Tarkanyi, F.; Takacs, S.; Csikai, J.; Takacs, M. P.; Ignatyuk, A.

    2013-09-01

    Activation products of rare earth elements are gaining importance in medical and technical applications. In stacked foil irradiations, followed by high resolution gamma spectroscopy, the cross-sections for production of 161,165Er, 166gHo on 165Ho and 135,137m,137g,139Ce, 140La, 133m,133g,cumBa and 136Cs on natLa targets were measured up to 50 MeV. Reduced uncertainty is obtained by simultaneous remeasurement of the 27Al(d,x)24,22Na monitor reactions over the whole energy range. A comparison with experimental literature values and results from updated theoretical codes (ALICE-D, EMPIRE-D and the TENDL2012 online library) is discussed.

  18. Results of drug correction of structural and functional changes in the gingiva in experimental gastroduodenitis.

    PubMed

    Romanenko, E G

    2014-04-01

    Morphological changes in the gingiva under the effect of drugs improving microcirculation were studied in pubertal Wistar rats with experimental gastroduodenitis. Chronic gastroduodenitis was induced by intragastric administration of 50% medical bile (1 ml/100 g body weight daily) for 40 days. The best medical correction was attained with altan and citrarginine. Morphologic studies showed signs of regeneration plastic activity of the epithelium, restructuring of the gingival lamina propria, and enlargement of the vascular bed area. Calcium-D3 Nycomed disordered the regeneration processes in the rat epithelium, because of calcium ion capacity to increase oxygen demand in tissues and cause destructive processes. Hence, pathogenetic drug correction of degenerative processes in the gingiva under conditions of chronic gastroduodenitis should include drugs promoting recovery of the microcirculatory bed, altan and citrarginine.

  19. Atmospheric channel transfer function estimation from experimental free-space optical communications data

    NASA Astrophysics Data System (ADS)

    Reinhardt, Colin N.; Kuga, Yasuo; Ritcey, James A.; Ishimaru, Akira; Hammel, Stephen; Tsintikidis, Dimitris

    2011-09-01

    The performance of terrestrial free-space optical communications systems is severely impaired by atmospheric aerosol particle distributions where the particle size is on the order of the operating wavelength. For optical and near-infrared wavelengths, fog droplets cause multiple-scattering and absorption effects which rapidly degrade received symbol detection performance as the optical depth parameter increases (visibility decreases). Using a custom free-space optical communications system we measured field data in fog within the optical multiple-scattering regime. We investigate the behavior of the estimated channel transfer function using both real field-test data and simulated propagation data based on field-test conditions. We then compare the channel transfer function estimates against the predictions computed using a radiative-transfer theory model-based approach which we also developed previously for the free-space optical atmospheric channel.

  20. Treatment of experimental stroke with opiate antagonists. Effects on neurological function, infarct size, and survival.

    PubMed

    Baskin, D S; Hosobuchi, Y; Grevel, J C

    1986-01-01

    The effects are reported of acute and long-term continuous administration of three opiate antagonists--naloxone, naltrexone, and diprenorphine--on neurological function, survival, and infarct size in a feline model of acute focal cerebral ischemia. All three drugs produced statistically significant improvement in motor function following acute administration without concomitant changes in level of consciousness; saline had no effect. Naloxone and naltrexone significantly prolonged survival (p less than 0.01); diprenorphine did not. Infarct size was not altered by any treatment administered. These findings confirm previous work suggesting that, with the appropriate methodology, treatment with opiate antagonists partially reverses neurological deficits. They also show that opiate antagonists prolong survival in certain conditions of acute and subacute focal cerebral ischemia without altering the area of infarcted tissue.

  1. Experimental functional response and inter-individual variation in foraging rate of teal (Anas crecca).

    PubMed

    Arzel, C; Guillemain, M; Gurd, D B; Elmberg, J; Fritz, H; Arnaud, A; Pin, C; Bosca, F

    2007-05-01

    The functional response, i.e. the change in per capita food intake rate per time unit with changed food availability, is a widely used tool for understanding the ecology and behaviour of animals. However, waterfowl remain poorly explored in this context. In an aviary experiment we derived a functional response curve for teal (Anas crecca) foraging on rice (Oryza sativa) seeds. We found a linear relationship between intake rate and seed density, as expected for a filter-feeder. At high seed densities we found a threshold, above which intake rate still increased linearly but with a lower slope, possibly reflecting a switch from filter-feeding to a scooping foraging mode. The present study shows that food intake rate in teal is linearly related to food availability within the range of naturally occurring seed densities, a finding with major implications for management and conservation of wetland habitats.

  2. Consequences of niche overlap for ecosystem functioning: an experimental test with pond grazers.

    PubMed

    Wojdak, Jeremy M; Mittelbach, Gary G

    2007-08-01

    While the number of studies investigating the effects of species diversity on ecosystem properties continues to expand, few have explicitly examined how ecosystem functioning depends quantitatively on the degree of niche complementarity among species. We report the results of a microcosm experiment where similarity in habitat use among aquatic snail species was evaluated as a predictor of changes in community and ecosystem properties due to increasing species richness. Replicate microcosms with all possible one- and two-species combinations of a guild of six snail species were stocked with identical initial snail biomass. Microcosms with two species of snails had greater final snail biomass, lower attached algae biomass, and less total organic matter than monocultures. Snail species differed in their use of five distinct habitat types in the microcosms. Similarity in habitat use between a species pair was negatively related to the magnitude of change (e.g., deltaEF [change in ecosystem function]) in dissolved oxygen. periphyton biomass, and accrual of organic matter with a change in diversity. However, using the most stringent criterion for complementarity effects (e.g., Dmax [proportional deviation of the total polyculture yield from the highest yielding monoculture]), a relationship between species' niche similarity and changes in function with increasing species richness was only observed for dissolved oxygen. The identity of snail species present in the microcosms had strong effects on total organic matter, snail biomass, dissolved oxygen, periphyton biomass, and sedimentation rate. In this study, herbivore identity, sampling effects, and niche complementarity all appear to contribute to species richness effects on pond ecosystem properties and community structure. The analytical approach employed here may profitably be used in other systems to quantify the role of niche complementarity in species richness-ecosystem function relationships.

  3. The loss of interneuron functional diversity in the piriform cortex after induction of experimental epilepsy.

    PubMed

    Gavrilovici, Cezar; Pollock, Emily; Everest, Michelle; Poulter, Michael O

    2012-12-01

    Interneuronal functional diversity is thought to be an important factor in the control of neural network oscillations in many brain regions. Specifically, interneuron action potential firing patterns are thought to modulate brain rhythms. In neurological disorders such as epilepsy where brain rhythms are significantly disturbed interneuron function is largely unexplored. Thus the purpose of this study was to examine the functional diversity of piriform cortex interneurons (PC; an area of the brain that easily supports seizures) before and after kindling-induced epilepsy. Using cluster analysis, we found five control firing behaviors. These groups were termed: non-adapting very high frequency (NAvHF), adapting high frequency (AHF), adapting low frequency (ALF), strongly adapting low frequency (sALF), and weakly adapting low frequency (wALF). A morphological analysis showed these spiking patterns were not associated with any specific interneuronal morphology although we found that most of the cells displaying NAvHF firing pattern were multipolar. After kindling about 40% of interneuronal firing pattern changed, and neither the NAvHF nor the wALF phenotypes were found. We also found that in multipolar interneurons a long-lasting potassium current was increased. A qPCR analysis indicated Kv1.6 subtype was up-regulated after kindling. An immunocytochemical analysis showed that Kv1.6 protein expression on parvalbumin (multipolar) interneurons increased by greater than 400%. We also examined whether these changes could be due to the selective death of a subset of interneurons but found that there was no change in cell number. These data show an important loss of the functional diversity of interneurons in the PC. Our data suggest that under pathophysiological condition interneurons are plastic resulting in the attenuation of high frequency network oscillations in favor of low frequency network activity. This may be an important new mechanism by which network synchrony is

  4. Time constants and feedback transfer functions of EBR-II (Experimental Breeder Reactor) subassembly types

    SciTech Connect

    Grimm, K.N.; Meneghetti, D.

    1986-09-01

    Time constants, feedback reactivity transfer functions and power coefficients are calculated for stereotypical subassemblies in the EBR-II reactor. These quantities are calculated from nodal reactivities obtained from a reactor kinetic code analysis for a step change in power. Due to the multiplicity of eigenvalues, there are several time constants for each nodal position in a subassembly. Compared with these calculated values are analytically derived values for the initial node of a given channel.

  5. Experimental studies of mitochondrial function in CADASIL vascular smooth muscle cells

    SciTech Connect

    Viitanen, Matti; Sundström, Erik; Baumann, Marc; Tikka, Saara

    2013-02-01

    Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a familiar fatal progressive degenerative disorder characterized by cognitive decline, and recurrent stroke in young adults. Pathological features include a dramatic reduction of brain vascular smooth muscle cells and severe arteriopathy with the presence of granular osmophilic material in the arterial walls. Here we have investigated the cellular and mitochondrial function in vascular smooth muscle cell lines (VSMCs) established from CADASIL mutation carriers (R133C) and healthy controls. We found significantly lower proliferation rates in CADASIL VSMC as compared to VSMC from controls. Cultured CADASIL VSMCs were not more vulnerable than control cells to a number of toxic substances. Morphological studies showed reduced mitochondrial connectivity and increased number of mitochondria in CADASIL VSMCs. Transmission electron microscopy analysis demonstrated increased irregular and abnormal mitochondria in CADASIL VSMCs. Measurements of mitochondrial membrane potential (Δψ{sub m}) showed a lower percentage of fully functional mitochondria in CADASIL VSMCs. For a number of genes previously reported to be changed in CADASIL VSMCs, immunoblotting analysis demonstrated a significantly reduced SOD1 expression. These findings suggest that alteration of proliferation and mitochondrial function in CADASIL VSMCs might have an effect on vital cellular functions important for CADASIL pathology. -- Highlights: ► CADASIL is an inherited disease of cerebral vascular cells. ► Mitochondrial dysfunction has been implicated in the pathogenesis of CADASIL. ► Lower proliferation rates in CADASIL VSMC. ► Increased irregular and abnormal mitochondria and lower mitochondrial membrane potential in CADASIL VSMCs. ► Reduced mitochondrial connectivity and increased number of mitochondria in CADASIL VSMCs.

  6. [Asymmetric function of the pes hippocampi in experimental stress-induced arterial hypertension of albino rats].

    PubMed

    Ljowschina, I P; Hecht, K

    1976-01-01

    Relations between a unilateral lesion of circumscribed structures of the Pes hippocampi on the one hand, and stress-induced blood-pressure and learning behaviour, on the other, were studied. An asymmetric functioning of the CNS was analyzed, in which unilateral exclusion of right-hand hippocampal structures stimulates processes of excitation, while lesion of left-hand structures causes prevalence of inhibitory processes. The resulting impairment of the emotional equilibrium potentiates the stress action's contribution to the development of arterial hypertension.

  7. Prediction of regional functional impairment following experimental stroke via connectome analysis.

    PubMed

    Schmitt, O; Badurek, S; Liu, W; Wang, Y; Rabiller, G; Kanoke, A; Eipert, P; Liu, J

    2017-04-13

    Recent advances in functional connectivity suggest that shared neuronal activation patterns define brain networks linking anatomically separate brain regions. We sought to investigate how cortical stroke disrupts multiple brain regions in processing spatial information. We conducted a connectome investigation at the mesoscale-level using the neuroVIISAS-framework, enabling the analysis of directed and weighted connectivity in bilateral hemispheres of cortical and subcortical brain regions. We found that spatial-exploration induced brain activation mapped by Fos, a proxy of neuronal activity, was differentially affected by stroke in a region-specific manner. The extent of hypoactivation following spatial exploration is inversely correlated with the spatial distance between the region of interest and region damaged by stroke, in particular within the parietal association and the primary somatosensory cortex, suggesting that the closer a region is to a stroke lesion, the more it would be affected during functional activation. Connectome modelling with 43 network parameters failed to reliably predict regions of hypoactivation in stroke rats exploring a novel environment, despite a modest correlation found for the centrality and hubness parameters in the home-caged animals. Further investigation in the inhibitory versus excitatory neuronal networks and microcircuit connectivity is warranted to improve the accuracy of predictability in post-stroke functional impairment.

  8. Experimental warming alters potential function of the fungal community in boreal forest.

    PubMed

    Treseder, Kathleen K; Marusenko, Yevgeniy; Romero-Olivares, Adriana L; Maltz, Mia R

    2016-10-01

    Fungal community composition often shifts in response to warmer temperatures, which might influence decomposition of recalcitrant carbon (C). We hypothesized that evolutionary trade-offs would enable recalcitrant C-using taxa to respond more positively to warming than would labile C-using taxa. Accordingly, we performed a warming experiment in an Alaskan boreal forest and examined changes in the prevalence of fungal taxa. In a complementary field trial, we characterized the ability of fungal taxa to use labile C (glucose), intermediate C (hemicellulose or cellulose), or recalcitrant C (lignin). We also assigned taxa to functional groups (e.g., free-living filamentous fungi, ectomycorrhizal fungi, and yeasts) based on taxonomic identity. We found that response to warming varied most among taxa at the order level, compared to other taxonomic ranks. Among orders, ability to use lignin was significantly related to increases in prevalence in response to warming. However, the relationship was weak, given that lignin use explained only 9% of the variability in warming responses. Functional groups also differed in warming responses. Specifically, free-living filamentous fungi and ectomycorrhizal fungi responded positively to warming, on average, but yeasts responded negatively. Overall, warming-induced shifts in fungal communities might be accompanied by an increased ability to break down recalcitrant C. This change in potential function may reduce soil C storage under global warming.

  9. Soil microbial diversity and soil functioning affect competition among grasses in experimental microcosms.

    PubMed

    Bonkowski, Michael; Roy, Jacques

    2005-03-01

    A gradient of microbial diversity in soil was established by inoculating pasteurized soil with microbial populations of different complexity, which were obtained by a combination of soil fumigation and filtering techniques. Four different soil diversity treatments were planted with six different grass species either in monoculture or in polyculture to test how changes of general microbial functions, such as catabolic diversity and nutrient recycling efficiency would affect the performance of the plant communities. Relatively harsh soil treatments were necessary to elicit visible effects on major soil processes such as decomposition and nitrogen cycling due to the high redundancy and resilience of soil microbial communities. The strongest effects of soil diversity manipulations on plant growth occurred in polycultures where interspecific competition between plants was high. In polycultures, soil diversity reduction led to a gradual, linear decline in biomass production of one subordinate grass species (Bromus hordeaceus), which was compensated by increased growth of two intermediate competitors (Aegilops geniculata, B. madritensis). This negative covariance in growth of competing grass species smoothed the effects of soil diversity manipulations at the plant community level. As a result, total shoot biomass production remained constant. Apparently the effects of soil diversity manipulations were buffered because functional redundancy at both, the microbial and the plant community level complemented each other. The results further suggests that small trade-offs in plant fitness due to general functional shifts at the microbial level can be significant for the outcome of competition in plant communities and thus diversity at much larger scales.

  10. AMIGO2 modulates T cell functions and its deficiency in mice ameliorates experimental autoimmune encephalomyelitis.

    PubMed

    Li, Zhilin; Khan, Mohd Moin; Kuja-Panula, Juha; Wang, Hongyun; Chen, Yu; Guo, Deyin; Chen, Zhi Jane; Lahesmaa, Riitta; Rauvala, Heikki; Tian, Li

    2017-05-01

    The immune function of AMIGO2 is currently unknown. Here, we revealed novel roles of AMIGO2 in modulating T-cell functions and EAE using Amigo2-knockout (AMG2KO) mice. Amigo2 was abundantly expressed by murine T helper (Th) cells. Its deficiency impaired transplanted T-cell infiltration into the secondary lymphoid organs and dampened Th-cell activation, but promoted splenic Th-cell proliferation and abundancy therein. AMG2KO Th cells had respectively elevated T-bet in Th1- and GATA-3 in Th2-lineage during early Th-cell differentiation, accompanied with increased IFN-γ and IL-10 but decreased IL-17A production. AMG2KO mice exhibited ameliorated EAE, dampened spinal T-cell accumulation, decreased serum IL-17A levels and enhanced splenic IL-10 production. Adoptive transfer of encephalitogenic AMG2KO T cells induced milder EAE and dampened spinal Th-cell accumulation and Tnf expression. Mechanistically, Amigo2-overexpression in 293T cells dampened NF-kB transcriptional activity, while Amigo2-deficiency enhanced Akt but suppressed GSK-3β phosphorylation and promoted nuclear translocations of NF-kB and NFAT1 in Th-cells. Collectively, our data demonstrate that AMIGO2 is important in regulating T-cell functions and EAE, and may be harnessed as a potential therapeutic target for multiple sclerosis.

  11. Natural dye extracted from karkadah and its application in dye-sensitized solar cells: experimental and density functional theory study.

    PubMed

    Reda, S M; Soliman, K A

    2016-02-01

    This work presents an experimental and theoretical study of cyanidin natural dye as a sensitizer for ZnO dye-sensitized solar cells. ZnO nanoparticles were prepared using ammonia and oxalic acid as a capping agent. The calculated average size of the synthesized ZnO with different capping agents was found to be 32.1 nm. Electronic properties of cyanidin and delphinidin dye were studied using density functional theory (DFT) and time-dependent DFT with a B3LYP/6-31G(d,p) level. By comparing the theoretical results with the experimental data, the cyanidin dye can be used as a sensitizer in dye-sensitized solar cells. An efficiency of 0.006% under an AM-1.5 illumination at 100  mW/cm(2) was attained. The influence of dye adsorption time on the solar cell performance is discussed.

  12. Monte Carlo calculation of the spatial response (Modulated Transfer Function) of a scintillation flat panel and comparison with experimental results

    NASA Astrophysics Data System (ADS)

    Juste, Belén; Miró, Rafael; Monasor, Paula; Verdú, Gumersindo

    2015-11-01

    Phosphor screens are commonly used in many X-ray imaging applications. The design and optimization of these detectors can be achieved using Monte Carlo codes to simulate radiation transport in scintillation materials and to improve the spatial response. This work presents an exhaustive procedure to measure the spatial resolution of a scintillation flat panel image and to evaluate the agreement with data obtained by simulation. To evaluate the spatial response we have used the Modulated Transfer Function (MTF) parameter. According to this, we have obtained the Line Spread Function (LSF) of the system since the Fourier Transform (FT) of the LSF gives the MTF. The experimental images were carried out using a medical X-ray tube (Toshiba E7299X) and a flat panel (Hammamatsu C9312SK). Measurements were based on the slit methodology experimental implementation, which measures the response of the system to a line. LSF measurements have been performed using a 0.2 mm wide lead slit superimposed over the flat panel. The detector screen was modelled with MCNP (version 6) Monte Carlo simulation code in order to analyze the effect of the acquisition setup configuration and to compare the response of scintillator screens with the experimental results. MCNP6 offers the possibility of studying the optical physics parameters (optical scattering and absorption coefficients) that occur in the phosphor screen. The study has been tested for different X-ray tube voltages, from 100 to 140 kV. An acceptable convergence between the MTF results obtained with MCNP6 and the experimental measurements have been obtained.

  13. Geniposide ameliorates TNBS-induced experimental colitis in rats via reducing inflammatory cytokine release and restoring impaired intestinal barrier function.

    PubMed

    Xu, Bin; Li, Yan-Li; Xu, Ming; Yu, Chang-Chun; Lian, Meng-Qiao; Tang, Ze-Yao; Li, Chuan-Xun; Lin, Yuan

    2017-03-06

    Geniposide is an iridoid glycosides purified from the fruit of Gardenia jasminoides Ellis, which is known to have antiinflammatory, anti-oxidative and anti-tumor activities. The present study aimed to investigate the effects of geniposide on experimental rat colitis and to reveal the related mechanisms. Experimental rat colitis was induced by rectal administration of a TNBS solution. The rats were treated with geniposide (25, 50 mg·kg(-1)·d(-1), ig) or with sulfasalazine (SASP, 100 mg·kg(-1)·d(-1), ig) as positive control for 14 consecutive days. A Caco-2 cell monolayer exposed to lipopolysaccharides (LPS) was used as an epithelial barrier dysfunction model. Transepithelial electrical resistance (TER) was measured to evaluate intestinal barrier function. In rats with TNBS-induced colitis, administration of geniposide or SASP significantly increased the TNBS-decreased body weight and ameliorated TNBS-induced experimental colitis and related symptoms. Geniposide or SASP suppressed inflammatory cytokine (TNF-α, IL-1β, and IL-6) release and neutrophil infiltration (myeloperoxidase activity) in the colon. In Caco-2 cells, geniposide (25-100 μmol/L) ameliorated LPS-induced endothelial barrier dysfunction via dose-dependently increasing transepithelial electrical resistance (TER). The results from both in vivo and in vitro studies revealed that geniposide down-regulated NF-κB, COX-2, iNOS and MLCK protein expression, up-regulated the expression of tight junction proteins (occludin and ZO-1), and facilitated AMPK phosphorylation. Both AMPK siRNA transfection and AMPK overexpression abrogated the geniposide-reduced MLCK protein expression, suggesting that geniposide ameliorated barrier dysfunction via AMPK-mediated inhibition of the MLCK pathway. In conclusion, geniposide ameliorated TNBS-induced experimental rat colitis by both reducing inflammation and modulating the disrupted epithelial barrier function via activating the AMPK signaling pathway..

  14. Functional analysis of T-cell subsets in chronic experimental alcoholism.

    PubMed Central

    Bagasra, O; Howeedy, A; Dorio, R; Kajdacsy-Balla, A

    1987-01-01

    In order to obtain a better understanding of immune system function in chronic alcoholism, we have assessed primary B-cell responses to helper T-cell independent (TI) and dependent (TD) antigens in chronic alcoholic Sprague-Dawley male rats fed totally liquid diet containing ethanol. Pair-fed littermates received the same diet except that carbohydrates isocalorically replaced ethanol, which accounted for 36% of the total calories. The ability of alcoholic animals to mount primary in vivo splenic plaque-forming cell (PFC) responses to TI pneumococcal polysaccharide type III (SIII) was elevated throughout 50 days of observation when compared to pair-fed controls; serum antibody responses to SIII paralleled the enhanced PFC responses. Primary in vivo B-cell responses to antigen sheep red blood cells (SRBC), a TD antigen, were initially elevated but were found to be significantly suppressed 30 days after chronic ethanol consumption. The degree of immunosuppression increased with length of chronic ethanol consumption. The elevated primary splenic PFC responses to TI (SIII) may be attributed to loss of T-suppressor cell control, since alcoholic rat spleen cells did not respond to low-dose priming with SIII. We suggest that either loss of function and/or actual depletion of accessory and regulatory cells (T-suppressor and T-helper) may be responsible for irregularities in B-cell function observed during chronic alcoholism. T-cell subset enumeration using fluorescein-labelled monoclonal antibodies revealed that a sequential T-helper and T-suppressor loss occurred several days following dysfunction of these T-cell subsets in splenic populations, suggesting that a combination of numerical and dysfunctional changes in lymphocyte subpopulations may be responsible for the immunological alterations observed in chronic alcoholics. PMID:2953674

  15. Relationship of dietary iodide and drinking water disinfectants to thyroid function in experimental animals

    SciTech Connect

    Revis, N.W.; McCauley, P.; Holdsworth, G.

    1986-11-01

    The importance of dietary iodide on the reported hypothyroid effect of drinking water disinfectants on thyroid function was investigated. Previous studies have also showed differences in the relative sensitivity of pigeons and rabbits to chlorinated water. Pigeons and rabbits were exposed for 3 months to diets containing high (950 ppb) or low (300 ppb) levels of iodide and to drinking water containing two levels of chlorine. Results showed that the high-iodide diet prevented the hypothyroid effect observed in pigeons given the low-iodide diet and chlorinated drinking water. Similar trends were observed in rabbits exposed to the same treatment; however, significant hypothyroid effects were not observed in this animal model. The factor associated with the observed effect of dietary iodide on the chlorine-induced change in thyroid function is unknown, as is the relative sensitivity of rabbits and pigeons to the effect of chlorine. Several factors may explain the importance of dietary iodide and the relative sensitivity of these species. For example, the iodine formed by the known reaction of chlorine with iodide could result in a decrease in the plasma level of iodide because of the relative absorption rates of iodide and iodine in the intestinal tract, and the various types and concentrations of chloroorganics (metabolites) formed in the diet following the exposure of various dietary constituents to chlorine could affect the thyroid function. The former factor was investigated in the present studies. Results do not confirm a consistent, significant reduction in the plasma level of iodide in rabbits and pigeons exposed to chlorinated water and the low-iodide diet. The latter factor is being investigated.

  16. Functional properties of butter oil made from bovine milk with experimentally altered fat composition.

    PubMed

    Ortiz-Gonzalez, G; Jimenez-Flores, R; Bremmer, D R; Clark, J H; DePeters, E J; Schmidt, S J; Drackley, J K

    2007-11-01

    Modification of milk fat composition might be desirable to alter manufacturing characteristics or produce low saturated fat dairy products that more closely meet consumer dietary preferences. The aim of this research was to evaluate functional properties of butter oil obtained from milks with fat composition modified by altering the profile of long-chain fatty acids (FA) absorbed from the small intestine of cows. A control and 5 mixtures of long-chain free FA were infused into the abomasum of lactating dairy cows in a 6 x 6 Latin square design with 21-d periods. Treatments were 1) control (no FA infused), 2) mostly saturated FA (C16:C18 = 0.72), 3) low-linoleic palm FA (C16:C18 = 0.85), 4) palm FA (C16:C18 = 0.72), 5) soy FA (C16:C18 = 0.10), and 6) high-palmitic soy FA (C16:C18 = 0.68). All treatments included meat solubles and Tween 80 as emulsifiers. Solid fat content (from 0 to 40 degrees C), melting point, and force at fracture were determined in butter oil. Milk fat from cows infused with palm FA (treatment 4) exhibited functionality equal to or better than control butter oil. Infusion with palm FA increased amounts of triglyceride (TG) fractions with 48, 52, and 54 carbon numbers but decreased TG with 32, 34, 36, and 42 carbon numbers. Infusion with soy FA increased TG with 26, 38, 40, 52, and 54 carbon numbers but decreased TG with 34, 42, and 46 carbons. Infusion of the mostly saturated FA increased TG with 38, 50, 52, and 54 carbon numbers but decreased TG with 32, 34, and 42 carbon numbers. These TG groups were consistently correlated with functional properties of butter oils from different treatments. The content of palmitic acid is important for maintaining functionality in the presence of increased polyunsaturated FA. The composition of milk fat may be able to be optimized through nutritional manipulation of diets for dairy cows if the optimal composition of FA and TG is defined for a particular dairy product.

  17. Pycnogenol® and its fractions influence the function of isolated heart in rats with experimental diabetes mellitus.

    PubMed

    Kralova, Eva; Jankyova, Stanislava; Mucaji, Pavel; Gresakova, Eva; Stankovicova, Tatiana

    2015-02-01

    The aim of this study was to test the effect of Pycnogenol(®) (PYC) mixture and its three fractions (buthanolic, water, ethyl acetate) on heart function in rats with experimental diabetes mellitus (DM) and compare their effects to the diabetic group. Their antioxidant activity "in vitro" was also determined. DM rats (streptozotocin over 3 consecutive days at a dose of 25 mg/kg of body weight) had increased systolic blood pressure, thicker left ventriculi wall (LV) and weaker myocardial contraction, prolonged QT interval in comparison to controls rats. In comparison to the diabetic group, PYC (20 mg/kg b.w./day) suppressed the influence of DM on the LV, improved contraction, increased coronary flow and displayed negative effect on electrical activity of hearts. The most effective of PYC's fractions was the water fraction. It improved biometric parameters and hemodynamic function of the DM hearts, enhanced shortening the QT interval, reduced the amount of dysrhythmias of the DM hearts and had the strongest antioxidant activity. In conclusion, DM damaged isolated rat heart function. Only the water fraction improved the function of the diabetic heart. The different results of three fractions and PYC on myocardial function may be caused by a various lipo- and hydro-philic action of the PYC components.

  18. Experimental Gestational Diabetes Mellitus Induces Blunted Vasoconstriction and Functional Changes in the Rat Aorta

    PubMed Central

    Tufiño, Cecilia; Villanueva-López, Cleva; Ibarra-Barajas, Maximiliano; Bracho-Valdés, Ismael; Bobadilla-Lugo, Rosa Amalia

    2014-01-01

    Diabetic conditions increase vascular reactivity to angiotensin II in several studies but there are scarce reports on cardiovascular effects of hypercaloric diet (HD) induced gestational diabetes mellitus (GDM), so the objective of this work was to determine the effects of HD induced GDM on vascular responses. Angiotensin II as well as phenylephrine induced vascular contraction was tested in isolated aorta rings with and without endothelium from rats fed for 7 weeks (4 before and 3 weeks during pregnancy) with standard (SD) or hypercaloric (HD) diet. Also, protein expression of AT1R, AT2R, COX-1, COX-2, NOS-1, and NOS-3 and plasma glucose, insulin, and angiotensin II levels were measured. GDM impaired vasoconstrictor response (P < 0.05 versus SD) in intact (e+) but not in endothelium-free (e−) vessels. Losartan reduced GDM but not SD e− vasoconstriction (P < 0.01 versus SD). AT1R, AT2R, and COX-1 and COX-2 protein expression were significantly increased in GDM vessels (P < 0.05 versus SD). Results suggest an increased participation of endothelium vasodilator mediators, probably prostaglandins, as well as of AT2 vasodilator receptors as a compensatory mechanism for vasoconstrictor changes generated by experimental GDM. Considering the short term of rat pregnancy findings can reflect early stage GDM adaptations. PMID:25610861

  19. Experimental approaches to identify cellular G-quadruplex structures and functions.

    PubMed

    Di Antonio, Marco; Rodriguez, Raphaël; Balasubramanian, Shankar

    2012-05-01

    Guanine-rich nucleic acids can fold into non-canonical DNA secondary structures called G-quadruplexes. The formation of these structures can interfere with the biology that is crucial to sustain cellular homeostases and metabolism via mechanisms that include transcription, translation, splicing, telomere maintenance and DNA recombination. Thus, due to their implication in several biological processes and possible role promoting genomic instability, G-quadruplex forming sequences have emerged as potential therapeutic targets. There has been a growing interest in the development of synthetic molecules and biomolecules for sensing G-quadruplex structures in cellular DNA. In this review, we summarise and discuss recent methods developed for cellular imaging of G-quadruplexes, and the application of experimental genomic approaches to detect G-quadruplexes throughout genomic DNA. In particular, we will discuss the use of engineered small molecules and natural proteins to enable pull-down, ChIP-Seq, ChIP-chip and fluorescence imaging of G-quadruplex structures in cellular DNA.

  20. Paeoniflorin Ameliorates Experimental Autoimmune Encephalomyelitis via Inhibition of Dendritic Cell Function and Th17 Cell Differentiation

    PubMed Central

    Zhang, Han; Qi, Yuanyuan; Yuan, Yuanyang; Cai, Li; Xu, Haiyan; Zhang, Lili; Su, Bing; Nie, Hong

    2017-01-01

    Paeoniflorin (PF) is a monoterpene glycoside and exhibits multiple effects, including anti-inflammation and immunoregulation. To date, the effect of PF on multiple sclerosis (MS) has not been investigated. In this study, we investigated the effect of PF in experimental autoimmune encephalomyelitis (EAE), an animal model for MS. After administered with PF, the onset and clinical symptoms of EAE mice were significantly ameliorated, and the number of Th17 cells infiltrated in central nervous system (CNS) and spleen was also dramatically decreased. Instead of inhibiting the differentiation of Th17 cells directly, PF influenced Th17 cells via suppressing the expression of costimulatory molecules and the production of interlukin-6 (IL-6) of dendritic cells (DCs) in vivo and in vitro, which may be attributable to the inhibition of IKK/NF-κB and JNK signaling pathway. When naïve CD4+ T cells were co-cultured with PF-treated dendritic cells under Th17-polarizing condition, the percentage of Th17 cells and the phosphorylation of STAT3 were decreased, as well as the mRNA levels of IL-17, RORα, and RORγt. Our study provided insights into the role of PF as a unique therapeutic agent for the treatment of multiple sclerosis and illustrated the underlying mechanism of PF from a new perspective. PMID:28165507

  1. Hydrogen-rich water improves neurological functional recovery in experimental autoimmune encephalomyelitis mice.

    PubMed

    Zhao, Ming; Liu, Ming-Dong; Pu, Ying-Yan; Wang, Dan; Xie, Yu; Xue, Gai-Ci; Jiang, Yong; Yang, Qian-Qian; Sun, Xue-Jun; Cao, Li

    2016-05-15

    Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system (CNS). The high costs, inconvenient administration, and side effects of current Food and Drug Administration (FDA)-approved drugs often lead to poor adherence to the long-term treatment of MS. Molecular hydrogen (H2) has been reported to exhibit anti-oxidant, anti-apoptotic, anti-inflammatory, anti-allergy, and anti-cancer effects. In the present study, we explored the prophylactic and therapeutic effects of hydrogen-rich water (HRW) on the progress of experimental autoimmune encephalomyelitis (EAE), the animal model for MS. We found that prophylactic administration of both 0.36mM and 0.89mM HRW was able to delay EAE onset and reduce maximum clinical scores. Moreover, 0.89mM HRW also reduced disease severity, CNS infiltration, and demyelination when administered after the onset of disease. Furthermore, HRW treatment prevented infiltration of CD4(+) T lymphocytes into the CNS and inhibited Th17 cell development without affecting Th1 cell populations. Because HRW is non-toxic, inexpensive, easily administered, and can readily cross the blood-brain barrier, our experiments suggest that HRW may have great potential in the treatment of MS.

  2. Getting the timing right: experimental protocols for investigating time with functional neuroimaging and psychopharmacology.

    PubMed

    Coull, Jennifer T

    2014-01-01

    Functional Magnetic Resonance Imaging (fMRI) is an effective tool for identifying brain areas and networks implicated in human timing. But fMRI is not just a phrenological tool: by careful design, fMRI can be used to disentangle discrete components of a timing task and control for the underlying cognitive processes (e.g. sustained attention and WM updating) that are critical for estimating stimulus duration in the range of hundreds of milliseconds to seconds. Moreover, the use of parametric designs and correlational analyses allows us to better understand not just where, but also how, the brain processes temporal information. In addition, by combining fMRI with psychopharmacological manipulation, we can begin to uncover the complex relationship between cognition, neurochemistry and anatomy in the healthy human brain. This chapter provides an overview of some of the key findings in the functional imaging literature of both duration estimation and temporal prediction, and outlines techniques that can be used to allow timing-related activations to be interpreted more unambiguously. In our own studies, we have found that estimating event duration, whether that estimate is provided by a motor response or a perceptual discrimination, typically recruits basal ganglia, SMA and right inferior frontal cortex, and can be modulated by dopaminergic activity in these areas. By contrast, orienting attention to predictable moments in time in order to optimize behaviour, whether that is to speed motor responding or improve perceptual accuracy, recruits left inferior parietal cortex.

  3. Inhibition of LINGO-1 promotes functional recovery after experimental spinal cord demyelination.

    PubMed

    Zhang, Yongjie; Zhang, Yi Ping; Pepinsky, Blake; Huang, Guanrong; Shields, Lisa B E; Shields, Christopher B; Mi, Sha

    2015-04-01

    Blocking LINGO-1 has been shown to enhance remyelination in the rat lysolecithin-induced focal spinal cord demyelination model. We used transcranial magnetic motor-evoked potentials (tcMMEPs) to assess the effect of blocking LINGO-1 on recovery of axonal function in a mouse lysolecithin model at 1, 2 and 4weeks after injury. The role of LINGO-1 was assessed using LINGO-1 knockout (KO) mice and in wild-type mice after intraperitoneal administration of anti-LINGO-1 antagonist monoclonal antibody (mAb3B5). Response rates (at 2 and 4weeks) and amplitudes (at 4weeks) were significantly increased in LINGO-1 KO and mAb3B5-treated mice compared with matched controls. The latency of potentials at 4weeks was significantly shorter in mAb3B5-treated mice compared with controls. Lesion areas in LINGO-1 KO and mAb3B5-treated mice were reduced significantly compared with matched controls. The number of remyelinated axons within the lesions was increased and the G-ratios of the axons were decreased in both LINGO-1 KO and mAb3B5-treated mice compared with matched controls. These data provide morphometric and functional evidence of enhancement of remyelination associated with antagonism of LINGO-1.

  4. Experimental verification of dosimetry predictions of bremsstrahlung attenuation as a function of material and electron energy

    SciTech Connect

    Sanford, T.W.L.; Halbleib, J.A.; Beutler, D.E.; Knott, D.P.

    1993-05-01

    Dose attenuation with depth in an absorber of on-axis bremsstrahlung generated from an electron target is measured and shown to agree within {plus_minus}9% with Monte Carlo predictions as a function of absorber material (Al, Fe, Pb) and incident electron-beam energy (5.5--25.1 MeV). For this on-axis bremsstrahlung, 1 to 5 g/cm{sup 2} of upstream and 0.2 to 1 g/cm{sup 2} of downs Al buffer is sufficient to provide electron equilibration for CaF{sub 2}:Mn thermoluminescent dosimeter (TLDs) over the measured energy range of 5.5 to 25.1 MeV, respectively. Once ``effective`` equilibration has been established, an expression of the form DA/Q = C{sub 1}V{sup c{sub 2}}e{sup {minus}C}{sub 3}V{sup c}{sub 4}{ell}, can be used to predict the dose-area (DA) product per absorbed beam charge (Q) at a given incident beam energy (V) in TLDs as a function of depth ({ell}) in absorbers, within a fixed solid angle centered about the beam axis. This expression is quantified for the measurements presented here.

  5. Experimental verification of bremsstrahlung production and dosimetry predictions as a function of energy and angle

    SciTech Connect

    Beutler, D.E.; Halbleib, J.A.; Sanford, T.W.L. ); Knott, D.P. )

    1994-12-01

    The integrated TIGER series (ITS) of coupled electron/photon Monte Carlo transport codes is widely used to predict the radiation output from flash x-ray sources and for the design of bremsstrahlung converters. The codes are also used to predict the response of radiation diagnostics (e.g., thermoluminescent dosimeters (TLD's)) and the response of electronic components and subsystems. Hence, the demonstration of the validity of the ITS codes for these applications is important. Here, measurements of energy deposition from bremsstrahlung production as a function of angle and beam energy (5-25 MeV) are shown to be in excellent agreement with Monte Carlo predictions. Dosimetry measurements are made and predicted in both equilibrated and under equilibrated radiation environments. In the latter case the quality of the agreement requires an accurate prediction of both the photon and electron spectra produced by the primary electron beam. An improved empirical equation for predicting bremsstrahlung production is also presented. This empirical relation can be used to estimate doses without resorting to expensive calculational efforts. It also gives an analytical relationship for dose as a function of energy and angle for a converter optimized for bremsstrahlung production using 15.5 MeV electrons.

  6. PPARα augments heart function and cardiac fatty acid oxidation in early experimental polymicrobial sepsis.

    PubMed

    Standage, Stephen W; Bennion, Brock G; Knowles, Taft O; Ledee, Dolena R; Portman, Michael A; McGuire, John K; Liles, W Conrad; Olson, Aaron K

    2017-02-01

    Children with sepsis and multisystem organ failure have downregulated leukocyte gene expression of peroxisome proliferator-activated receptor-α (PPARα), a nuclear hormone receptor transcription factor that regulates inflammation and lipid metabolism. Mouse models of sepsis have likewise demonstrated that the absence of PPARα is associated with decreased survival and organ injury, specifically of the heart. Using a clinically relevant mouse model of early sepsis, we found that heart function increases in wild-type (WT) mice over the first 24 h of sepsis, but that mice lacking PPARα (Ppara(-/-)) cannot sustain the elevated heart function necessary to compensate for sepsis pathophysiology. Left ventricular shortening fraction, measured 24 h after initiation of sepsis by echocardiography, was higher in WT mice than in Ppara(-/-) mice. Ex vivo working heart studies demonstrated greater developed pressure, contractility, and aortic outflow in WT compared with Ppara(-/-) mice. Furthermore, cardiac fatty acid oxidation was increased in WT but not in Ppara(-/-) mice. Regulatory pathways controlling pyruvate incorporation into the citric acid cycle were inhibited by sepsis in both genotypes, but the regulatory state of enzymes controlling fatty acid oxidation appeared to be permissive in WT mice only. Mitochondrial ultrastructure was not altered in either genotype indicating that severe mitochondrial dysfunction is unlikely at this stage of sepsis. These data suggest that PPARα expression supports the hyperdynamic cardiac response early in the course of sepsis and that increased fatty acid oxidation may prevent morbidity and mortality.

  7. Analyzing Beneficial Effects of Nutritional Supplements on Intestinal Epithelial Barrier Functions During Experimental Colitis.

    PubMed

    Vargas Robles, Hilda; Castro Ochoa, Karla Fabiola; Nava, Porfirio; Silva Olivares, Angélica; Shibayama, Mineko; Schnoor, Michael

    2017-01-05

    Inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, are chronic relapsing disorders of the intestines. They cause severe problems, such as abdominal cramping, bloody diarrhea, and weight loss, in affected individuals. Unfortunately, there is no cure yet, and treatments only aim to alleviate symptoms. Current treatments include anti-inflammatory and immunosuppressive drugs that may cause severe side effects. This warrants the search for alternative treatment options, such as nutritional supplements, that do not cause side effects. Before their application in clinical studies, such compounds must be rigorously tested for effectiveness and security in animal models. A reliable experimental model is the dextran sulfate sodium (DSS) colitis model in mice, which reproduces many of the clinical signs of ulcerative colitis in humans. We recently applied this model to test the beneficial effects of a nutritional supplement containing vitamins C and E, L-arginine, and ω3-polyunsaturated fatty acids (PUFA). We analyzed various disease parameters and found that this supplement was able to ameliorate edema formation, tissue damage, leukocyte infiltration, oxidative stress, and the production of pro-inflammatory cytokines, leading to an overall improvement in the disease activity index. In this article, we explain in detail the correct application of nutritional supplements using the DSS colitis model in C57Bl/6 mice, as well as how disease parameters such as histology, oxidative stress, and inflammation are assessed. Analyzing the beneficial effects of different diet supplements may then eventually open new avenues for the development of alternative treatment strategies that alleviate IBD symptoms and/or that prolong the phases of remission without causing severe side effects.

  8. Quantitative imaging of cartilage and bone for functional assessment of gene therapy approaches in experimental arthritis.

    PubMed

    Stok, Kathryn S; Noël, Danièle; Apparailly, Florence; Gould, David; Chernajovsky, Yuti; Jorgensen, Christian; Müller, Ralph

    2010-07-01

    Anti-inflammatory gene therapy can inhibit inflammation driven by TNFalpha in experimental models of rheumatoid arthritis. However, assessment of the therapeutic effect on cartilage and bone quality is either missing or unsatisfactory. A multimodal imaging approach, using confocal laser scanning microscopy (CLSM) and micro-computed tomography (microCT), was used for gathering 3D quantitative image data on diseased and treated murine joints. As proof of concept, the efficacy of anti-TNF-based gene therapy was assessed, comparing imaging techniques with classical investigations. SCID mice knees were injected with human synoviocytes overexpressing TNFalpha. Two days later, electric pulse-mediated DNA transfer was performed after injection of the pGTRTT-plasmid containing a dimeric soluble-TNF receptor (dsTNFR) under the control of a doxycycline-inducible promoter. After 21 days the mice were sacrificed, TNFalpha levels were measured and the joints assessed for cartilage and bone degradation, using CLSM, microCT and histology. TNFalpha levels were decreased in the joints of mice treated with the plasmid in the presence of doxycycline. Concomitantly, histological analysis showed an increase in cartilage thickness and a decrease in specific synovial hyperplasia and cartilage erosion. Bone morphometry revealed that groups with the plasmid in the presence of doxycycline displayed a higher cortical thickness and decreased porosity. Using an anti-TNF gene therapy approach, known to reduce inflammation, as proof of concept, 3D imaging allowed quantitative evaluation of its benefits to joint architecture. It showed that local delivery of a regulated anti-TNF vector allowed decreasing arthritis severity through TNFalpha inhibition. These tools are valuable for understanding the efficacy of gene therapy on whole-joint morphometry.

  9. Catechin averts experimental diabetes mellitus-induced vascular endothelial structural and functional abnormalities.

    PubMed

    Bhardwaj, Pooja; Khanna, Deepa; Balakumar, Pitchai

    2014-03-01

    Diabetes mellitus is associated with an induction of vascular endothelial dysfunction (VED), an initial event that could lead to the pathogenesis of atherosclerosis and hypertension. Previous studies showed that catechin, a key component of green tea, possesses vascular beneficial effects. We investigated the effect of catechin hydrate in diabetes mellitus-induced experimental vascular endothelial abnormalities (VEA). Streptozotocin (50 mg/kg, i.p., once) administration to rats produced diabetes mellitus, which subsequently induced VEA in 8 weeks by markedly attenuating acetylcholine-induced endothelium-dependent relaxation in the isolated aortic ring preparation, decreasing aortic and serum nitrite/nitrate concentrations and impairing aortic endothelial integrity. These abnormalities in diabetic rats were accompanied with elevated aortic superoxide anion generation and serum lipid peroxidation in addition to hyperglycemia. Catechin hydrate treatment (50 mg/kg/day p.o., 3 weeks) markedly prevented diabetes mellitus-induced VEA and vascular oxidative stress. Intriguingly, in vitro incubation of L-NAME (100 μM), an inhibitor of nitric oxide synthase, or Wortmannin (100 nM), a selective inhibitor of phosphatidylinositol 3-kinase (PI3K), markedly prevented catechin hydrate-induced improvement in acetylcholine-provoked endothelium-dependent relaxation in the diabetic rat aorta. Moreover, catechin hydrate treatment considerably reduced the elevated level of serum glucose in diabetic rats. In conclusion, catechin hydrate treatment prevents diabetes mellitus-induced VED through the activation of endothelial PI3K signal and subsequent activation of eNOS and generation of nitric oxide. In addition, reduction in high glucose, vascular oxidative stress, and lipid peroxidation might additionally contribute to catechin hydrate-associated prevention of diabetic VEA.

  10. Experimental Testicular Torsion in a Rat Model: Effects of Treatment with Pausinystalia macroceras on Testis Functions

    PubMed Central

    Ikebuaso, Afamefuna Donatus; Yama, Oshiozokhai Eboetse; Duru, F.I.O.; Oyebadejo, S.A.

    2012-01-01

    Background Testicular torsion is a medical emergency with catastrophic sequelae that deserves the same treatment considerations and concerted efforts in research as any other complicated medical condition. The aim of this study was to investigate the effect of Pausinystalia macroceras (PM) bark extract on sperm quality and serum testosterone levels in testicular torsion in a rat model. Methods Sixty–five (65) mature male Wistar rats apportioned randomly into four experimental groups of A to C; were further divided into four subgroups according to duration of torsion. Group D were the normal regular rats. Each group/subgroup comprised five rats. Testis maintained in the torted position (T) for 1, 2, 3 and 4 hr in Group A (subgroups: AT1+PM, AT2+PM, AT3+PM, and AT4+PM). Group B (sub- groups: B1+PM, B2+PM, B3+PM, B4+PM) were sham–operated animals, which did not undergo torsion and served as the sham control group. Group C subgroups: CT1, CT2, CT3 and CT4 were torted as in A. All animals (except groups C and D) were treated by PM extract (0.1 g/kg b.w. per day) for 56 days. Group D rats were fed distilled water. Serum testosterone concentrations and sperm quality (motility and count) were measured. Analyses of variance with Scheffe's post-hoc test were carried out on the data. Results PM extract had a positive effect (significant; p < 0.5) on the sperm count and motility in rats with testicular torsion compared to those not receiving the extract. There was also an increase in serum testosterone levels in the former groups. Conclusion Treatment of rats following testicular torsion result to the enhancement of sperm production in comparison with untreated rats. PMID:23926549

  11. Functional defects in NOD2 signaling in experimental and human Crohn disease.

    PubMed

    Corridoni, Daniele; Arseneau, Kristen O; Cominelli, Fabio

    2014-01-01

    Increasing evidence suggests that a deficit in innate immunity may play a causative role in the pathogenesis of inflammatory bowel disease. The most compelling support for this hypothesis comes from the genetic association of Crohn disease (CD) with carriage of polymorphisms within the NOD2 gene, which represent the most frequent genetic defect in CD. Our findings suggest that SAMP1/YitFc mice, which develop CD-like ileitis in the absence of NOD2 genetic mutations, fail to respond to MDP administration by displaying decreased innate cytokine production and impaired bacterial clearance before the onset of disease. This provides evidence that dysregulated NOD2 signaling, genetic or functional in nature, predisposes to chronic intestinal inflammation, and supports a new paradigm that CD may occur from a deficit in innate immunity as opposed to an overly aggressive immune response. This new paradigm could lead to potential development of new preventative or therapeutic modalities for patients with CD.

  12. Experimental design and multiple response optimization. Using the desirability function in analytical methods development.

    PubMed

    Candioti, Luciana Vera; De Zan, María M; Cámara, María S; Goicoechea, Héctor C

    2014-06-01

    A review about the application of response surface methodology (RSM) when several responses have to be simultaneously optimized in the field of analytical methods development is presented. Several critical issues like response transformation, multiple response optimization and modeling with least squares and artificial neural networks are discussed. Most recent analytical applications are presented in the context of analytLaboratorio de Control de Calidad de Medicamentos (LCCM), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, C.C. 242, S3000ZAA Santa Fe, ArgentinaLaboratorio de Control de Calidad de Medicamentos (LCCM), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, C.C. 242, S3000ZAA Santa Fe, Argentinaical methods development, especially in multiple response optimization procedures using the desirability function.

  13. Experimental and density functional study of Mn doped Bi2Te3 topological insulator

    NASA Astrophysics Data System (ADS)

    Ghasemi, A.; Kepaptsoglou, D.; Figueroa, A. I.; Naydenov, G. A.; Hasnip, P. J.; Probert, M. I. J.; Ramasse, Q.; van der Laan, G.; Hesjedal, T.; Lazarov, V. K.

    2016-12-01

    We present a nanoscale structural and density functional study of the Mn doped 3D topological insulator Bi2Te3. X-ray absorption near edge structure shows that Mn has valency of nominally 2+. Extended x-ray absorption fine structure spectroscopy in combination with electron energy loss spectroscopy (EELS) shows that Mn is a substitutional dopant of Bi and Te and also resides in the van der Waals gap between the quintuple layers of Bi2Te3. Combination of aberration-corrected scanning transmission electron microscopy and EELS shows that Mn substitution of Te occurs in film regions with increased Mn concentration. First-principles calculations show that the Mn dopants favor octahedral sites and are ferromagnetically coupled.

  14. Experimental verification of dosimetry predictions of bremsstrahlung attenuation as a function of material and electron energy

    SciTech Connect

    Sanford, T.W.L.; Halbleib, J.A.; Beutler, D.E. ); Knott, D.P. )

    1993-12-01

    Dose attenuation with depth in an absorber of on-axis bremsstrahlung generated from an electron target is measured and shown to agree within [+-]9% with Monte Carlo predictions as a function of absorber material (Al,Fe,Pb) and incident electron beam energy (5.5-25.1 MeV). For this on-axis bremsstrahlung, 1 to 5 g/cm[sup 2] of upstream and 0.2 to 1 g/cm[sup 2] of downstream Al buffer is sufficient to provide electron equilibration for CaF[sub 2]:Mn thermoluminescent dosimeters (TI-Ds) over the measured energy range of 5.5 to 25.1 MeV, respectively. Once effective'' equilibration has been established, an expression of the form DA/Q = C[sub 1]V[sup C[sub 2

  15. Experimental verification of dosimetry predictions of bremsstrahlung attenuation as a function of material and electron energy

    SciTech Connect

    Sanford, T.W.L.; Halbleib, J.A.; Beutler, D.E. ); Knott, D.P. )

    1993-01-01

    Dose attenuation with depth in an absorber of on-axis bremsstrahlung generated from an electron target is measured and shown to agree within [plus minus]9% with Monte Carlo predictions as a function of absorber material (Al, Fe, Pb) and incident electron-beam energy (5.5--25.1 MeV). For this on-axis bremsstrahlung, 1 to 5 g/cm[sup 2] of upstream and 0.2 to 1 g/cm[sup 2] of downs Al buffer is sufficient to provide electron equilibration for CaF[sub 2]:Mn thermoluminescent dosimeter (TLDs) over the measured energy range of 5.5 to 25.1 MeV, respectively. Once effective'' equilibration has been established, an expression of the form DA/Q = C[sub 1]V[sup c[sub 2

  16. Impact of Cardiopulmonary Bypass on Respiratory Mucociliary Function in an Experimental Porcine Model

    PubMed Central

    Sánchez-Véliz, Rodrigo; Carmona, Maria José; Otsuki, Denise Aya; Freitas, Claudia; Benício, Anderson; Negri, Elnara Marcia; Malbouisson, Luiz Marcelo

    2015-01-01

    Background The impact of cardiac surgery using cardiopulmonary bypass (CPB) on the respiratory mucociliary function is unknown. This study evaluated the effects of CPB and interruption of mechanical ventilation on the respiratory mucociliary system. Methods Twenty-two pigs were randomly assigned to the control (n = 10) or CPB group (n = 12). After the induction of anesthesia, a tracheostomy was performed, and tracheal tissue samples were excised (T0) from both groups. All animals underwent thoracotomy. In the CPB group, an aorto-bicaval CPB was installed and maintained for 90 minutes. During the CPB, mechanical ventilation was interrupted, and the tracheal tube was disconnected. A second tracheal tissue sample was obtained 180 minutes after the tracheostomy (T180). Mucus samples were collected from the trachea using a bronchoscope at T0, T90 and T180. Ciliary beat frequency (CBF) and in situ mucociliary transport (MCT) were studied in ex vivo tracheal epithelium. Mucus viscosity (MV) was assessed using a cone-plate viscometer. Qualitative tracheal histological analysis was performed at T180 tissue samples. Results CBF decreased in the CPB group (13.1 ± 1.9 Hz vs. 11.1 ± 2.1 Hz, p < 0.05) but not in the control group (13.1 ± 1 Hz vs. 13 ± 2.9 Hz). At T90, viscosity was increased in the CPB group compared to the control (p < 0.05). No significant differences were observed in in situ MCT. Tracheal histology in the CPB group showed areas of ciliated epithelium loss, submucosal edema and infiltration of inflammatory cells. Conclusion CPB acutely contributed to alterations in tracheal mucocilliary function. PMID:26288020

  17. Assessment of Gaussian-3 and density functional theories for a larger experimental test set

    NASA Astrophysics Data System (ADS)

    Curtiss, Larry A.; Raghavachari, Krishnan; Redfern, Paul C.; Pople, John A.

    2000-05-01

    The G2/97 test set [J. Chem. Phys. 106, 1063 (1997)] for assessing quantum chemical methods used to predict thermochemical data is expanded to include 75 additional enthalpies of formation of larger molecules. This new set, referred to as the G3/99 test set, includes enthalpies of formation, ionization potentials, electron affinities, and proton affinities in the G2/97 set and 75 new enthalpies of formation. The total number of energies in the G3/99 set is 376. Overall, G3 theory has a mean absolute deviation of 1.07 kcal/mol for the G3/99 test set and does about as well for the new hydrocarbons and substituted hydrocarbons as it does for those in the G2/97 test. However, G3 theory has large deviations for several of the new nonhydrogen systems in the G3/99 test set such as SF6 and PF5. Part of the source of error is traced to the inadequate geometries used in G3 theory for these molecules. Other variations of G3 theory are also assessed such as G3(MP2), G3(MP3), and the versions of G3 theory using scaled energy terms instead of the higher level correction. These variations also do well for the larger hydrocarbons and substituted hydrocarbons, but fail for the same nonhydrogen systems as G3 theory. The density functional methods assessed in this study, including the hybrid B3LYP method, all have much larger deviations from experiment for the new enthalpies of formation in the expanded test set; the mean absolute deviation more than doubles compared to that for the enthalpies in the G2/97 test set. This is due to a cumulative effect of the errors in the larger molecules in the density functional methods.

  18. Experimental evidence for friction-enhancing integumentary modifications of chameleons and associated functional and evolutionary implications

    PubMed Central

    Khannoon, Eraqi R.; Endlein, Thomas; Russell, Anthony P.; Autumn, Kellar

    2014-01-01

    The striking morphological convergence of hair-like integumentary derivatives of lizards and arthropods (spiders and insects) demonstrates the importance of such features for enhancing purchase on the locomotor substrate. These pilose structures are responsible for the unique tractive abilities of these groups of animals, enabling them to move with seeming ease on overhanging and inverted surfaces, and to traverse inclined smooth substrates. Three groups of lizards are well known for bearing adhesion-promoting setae on their digits: geckos, anoles and skinks. Similar features are also found on the ventral subdigital and distal caudal skin of chameleons. These have only recently been described in any detail, and structurally and functionally are much less well understood than are the setae of geckos and anoles. The seta-like structures of chameleons are not branched (a characteristic of many geckos), nor do they terminate in spatulate tips (which is characteristic of geckos, anoles and skinks). They are densely packed and have attenuated blunt, globose tips or broad, blade-like shafts that are flattened for much of their length. Using a force transducer, we tested the hypothesis that these structures enhance friction and demonstrate that the pilose skin has a greater frictional coefficient than does the smooth skin of these animals. Our results are consistent with friction being generated as a result of side contact of the integumentary filaments. We discuss the evolutionary and functional implications of these seta-like structures in comparison with those typical of other lizard groups and with the properties of seta-mimicking synthetic structures. PMID:24285195

  19. High-temperature thermo-mechanical behavior of functionally graded materials produced by plasma sprayed coating: Experimental and modeling results

    NASA Astrophysics Data System (ADS)

    Choi, Kang Hyun; Kim, Hyun-Su; Park, Chang Hyun; Kim, Gon-Ho; Baik, Kyoung Ho; Lee, Sung Ho; Kim, Taehyung; Kim, Hyoung Seop

    2016-09-01

    Thermal barrier coatings are widely used in aerospace industries to protect exterior surfaces from harsh environments. In this study, functionally graded materials (FGMs) were investigated with the aim to optimize their high temperature resistance and strength characteristics. NiCrAlY bond coats were deposited on Inconel-617 superalloy substrate specimens by the low vacuum plasma spraying technique. Functionally graded Ni-yttria-stabilized zirconia (YSZ) coatings with gradually varying amounts of YSZ (20%-100%) were fabricated from composite powders by vacuum plasma spraying. Heat shield performance tests were conducted using a high- temperature plasma torch. The temperature distributions were measured using thermocouples at the interfaces of the FGM layers during the tests. A model for predicting the temperature at the bond coating-substrate interface was established. The temperature distributions simulated using the finite element method agreed well with the experimental results.

  20. Ion velocity distribution functions in argon and helium discharges: detailed comparison of numerical simulation results and experimental data

    NASA Astrophysics Data System (ADS)

    Wang, Huihui; Sukhomlinov, Vladimir S.; Kaganovich, Igor D.; Mustafaev, Alexander S.

    2017-02-01

    Using the Monte Carlo collision method, we have performed simulations of ion velocity distribution functions (IVDF) taking into account both elastic collisions and charge exchange collisions of ions with atoms in uniform electric fields for argon and helium background gases. The simulation results are verified by comparison with the experiment data of the ion mobilities and the ion transverse diffusion coefficients in argon and helium. The recently published experimental data for the first seven coefficients of the Legendre polynomial expansion of the ion energy and angular distribution functions are used to validate simulation results for IVDF. Good agreement between measured and simulated IVDFs shows that the developed simulation model can be used for accurate calculations of IVDFs.

  1. Central Functions of the Lumenal and Peripheral Thylakoid Proteome of Arabidopsis Determined by Experimentation and Genome-Wide Prediction

    PubMed Central

    Peltier, Jean-Benoît; Emanuelsson, Olof; Kalume, Dário E.; Ytterberg, Jimmy; Friso, Giulia; Rudella, Andrea; Liberles, David A.; Söderberg, Linda; Roepstorff, Peter; von Heijne, Gunnar; van Wijk, Klaas J.

    2002-01-01

    Experimental proteome analysis was combined with a genome-wide prediction screen to characterize the protein content of the thylakoid lumen of Arabidopsis chloroplasts. Soluble thylakoid proteins were separated by two-dimensional electrophoresis and identified by mass spectrometry. The identities of 81 proteins were established, and N termini were sequenced to validate localization prediction. Gene annotation of the identified proteins was corrected by experimental data, and an interesting case of alternative splicing was discovered. Expression of a surprising number of paralogs was detected. Expression of five isomerases of different classes suggests strong (un)folding activity in the thylakoid lumen. These isomerases possibly are connected to a network of peripheral and lumenal proteins involved in antioxidative response, including peroxiredoxins, m-type thioredoxins, and a lumenal ascorbate peroxidase. Characteristics of the experimentally identified lumenal proteins and their orthologs were used for a genome-wide prediction of the lumenal proteome. Lumenal proteins with a typical twin-arginine translocation motif were predicted with good accuracy and sensitivity and included additional isomerases and proteases. Thus, prime functions of the lumenal proteome include assistance in the folding and proteolysis of thylakoid proteins as well as protection against oxidative stress. Many of the predicted lumenal proteins must be present at concentrations at least 10,000-fold lower than proteins of the photosynthetic apparatus. PMID:11826309

  2. An experimental study of permeability development as a function of crystal-free melt viscosity

    NASA Astrophysics Data System (ADS)

    Lindoo, A. N.; Larsen, J. F.

    2013-12-01

    The efficiency of volatile exsolution and degassing from an ascending magma influences eruption dynamics. We performed single-step decompression experiments using externally heated TZM alloy cold seal pressure vessels to investigate porosity-permeability relationships as a function of crystal-free melt viscosity. The experiments employed natural, finely powdered rhyolite (76 % SiO2), rhyodacite (70 % SiO2), K-phonolite (55 % SiO2), and basaltic andesite (54 % SiO2) starting compositions, with estimated viscosities varying between ~106-103 Pa s. We first held the experiments at water-saturated conditions of 900 (rhyolite, rhyodacite, and phonolite) and 1025°C (basaltic andesite) and 150 MPa for 2-72 hours. We decompressed the experiments isothermally to final pressures of 125 to 25 MPa at 1-5 MPa/s and quenched after holding for 0.25-60 minutes at the final pressure. After removing the run products from the capsules, we measured porosity using image processing methods and permeability using a gas permeameter. We employed the Forchheimer equation to estimate Darcian (viscous) and inertial permeabilities of each experiment. All experiments are impermeable below a critical porosity that appears to vary between the different melt compositions. For rhyolite samples, the permeability increases from 10-14 to 10-13 m2 at 63 - 80 vol. %, below which samples are impermeable. Rhyodacite is impermeable until the experiments reach ~67 vol. % porosity, at which the samples have viscous permeability of 10-12.3 m2; higher than the rhyolite at similar porosity. K-rich phonolite reaches viscous permeability of 10-14.5 m2 at 55 vol. % porosity. Basaltic andesite samples remain impermeable to pressures as low as 50 MPa. Our preliminary results indicate that the critical porosity at which magmas become permeable and degas during magma ascent may decrease as a function of decreasing melt viscosity. However, further experiments on the phonolite and basaltic andesite compositions are

  3. Effect of Additives on Green Sand Molding Properties using Design of Experiments and Taguchi's Quality Loss Function - An Experimental Study

    NASA Astrophysics Data System (ADS)

    Desai, Bhagyashree; Mokashi, Pavani; Anand, R. L.; Burli, S. B.; Khandal, S. V.

    2016-09-01

    The experimental study aims to underseek the effect of various additives on the green sand molding properties as a particular combination of additives could yield desired sand properties. The input parameters (factors) selected were water and powder (Fly ash, Coconut shell and Tamarind) in three levels. Experiments were planned using design of experiments (DOE). On the basis of plans, experiments were conducted to understand the behavior of sand mould properties such as compression strength, shear strength, permeability number with various additives. From the experimental results it could be concluded that the factors have significant effect on the sand properties as P-value found to be less than 0.05 for all the cases studied. The optimization based on quality loss function was also performed. The study revealed that the quality loss associated with the tamarind powder was lesser compared to other additives selected for the study. The optimization based on quality loss function and the parametric analysis using ANOVA suggested that the tamarind powder of 8 gm per Kg of molding sand and moisture content of 7% yield better properties to obtain sound castings.

  4. Experimental Modification of Rat Pituitary Growth Hormone Cell Function During and After Spaceflight

    NASA Technical Reports Server (NTRS)

    Hymer, W. C.; Salada, T.; Nye, P.; Grossman, E. J.; Lane, P. K.; Grindeland, R. E.

    1996-01-01

    Space-flown rats show a number of flight-induced changes in the structure and function of pituitary Growth Hormone (GH) cells after in vitro postflight testing. To evaluate the possible effects of microgravity on GH cells themselves, freshly dispersed rat anterior pituitary gland cells were seeded into vials containing serum +/- 1 micron HydroCortisone (HC) before flight. Five different cell preparations were used: the entire mixed-cell population of various hormone-producing cell types, cells of density less than 1.071 g/sq cm (band 1), cells of density greater than 1.071 g/sq cm (band 2), and cells prepared from either the dorsal or ventral part of the gland. Relative to ground control samples, bioactive GH released from dense cells during flight was reduced in HC-free medium but was increased in HC-containing medium. Band I and mixed cells usually showed opposite HC-dependent responses. Release of bioactive GH from ventral flight cells was lower; postflight responses to GH-releasing hormone challenge were reduced, and the cytoplasmic area occupied by GH in the dense cells was greater. Collectively, the data show that the chemistry and cellular makeup of the culture system modifies the response of GH cells to microgravity. As such, these cells offer a system to identify gravisensing mechanisms in secretory cells in future microgravity research.

  5. Simultaneous regularization method for the determination of radius distributions from experimental multiangle correlation functions.

    PubMed

    Buttgereit, R; Roths, T; Honerkamp, J; Aberle, L B

    2001-10-01

    Dynamic light scattering experiments have become a powerful tool in order to investigate the dynamical properties of complex fluids. In many applications in both soft matter research and industry so-called "real world" systems are subject of great interest. Here, the dilution of the investigated system often cannot be changed without getting measurement artifacts, so that one often has to deal with highly concentrated and turbid media. The investigation of such systems requires techniques that suppress the influence of multiple scattering, e.g., cross correlation techniques. However, measurements at turbid as well as highly diluted media lead to data with low signal-to-noise ratio, which complicates data analysis and leads to unreliable results. In this article a multiangle regularization method is discussed, which copes with the difficulties arising from such samples and enhances enormously the quality of the estimated solution. In order to demonstrate the efficiency of this multiangle regularization method we applied it to cross correlation functions measured at highly turbid samples.

  6. Techniques for estimating the unknown functions of incomplete experimental spectral and correlation response matrices

    NASA Astrophysics Data System (ADS)

    Antunes, Jose; Borsoi, Laurent; Delaune, Xavier; Piteau, Philippe

    2016-02-01

    In this paper, we propose analytical and numerical straightforward approximate methods to estimate the unknown terms of incomplete spectral or correlation matrices, when the cross-spectra or cross-correlations available from multiple measurements do not cover all pairs of transducer locations. The proposed techniques may be applied whenever the available data includes the auto-spectra at all measurement locations, as well as selected cross-spectra which implicates all measurement locations. The suggested methods can also be used for checking the consistency between the spectral or correlation functions pertaining to measurement matrices, in cases of suspicious data. After presenting the proposed spectral estimation formulations, we discuss their merits and limitations. Then we illustrate their use on a realistic simulation of a multi-supported tube subjected to turbulence excitation from cross-flow. Finally, we show the effectiveness of the proposed techniques by extracting the modal responses of the simulated flow-excited tube, using the SOBI (Second Order Blind Identification) method, from an incomplete response matrix 1

  7. Vocal tract function in birdsong production: experimental manipulation of beak movements.

    PubMed

    Hoese, W J; Podos, J; Boetticher, N C; Nowicki, S

    2000-06-01

    Kinematic analyses have demonstrated that the extent to which a songbird's beak is open when singing correlates with the acoustic frequencies of the sounds produced, suggesting that beak movements function to modulate the acoustic properties of the vocal tract during song production. If motions of the beak are necessary for normal song production, then disrupting the ability of a bird to perform these movements should alter the acoustic properties of its song. We tested this prediction by comparing songs produced normally by white-throated sparrows and swamp sparrows with songs produced when the beak was temporarily immobilized. We also observed how temporarily loading the beak of canaries with extra mass affected vocal tract movements and song production. Disruption of vocal tract movements resulted in the predicted frequency-dependent amplitude changes in the songs of both white-throated sparrows and swamp sparrows. Canaries with mass added to their beak sang with their beak open more widely than normal and produced notes with greater harmonic content than those without weights. Both manipulations resulted in acoustic changes consistent with a model in which beak motions affect vocal tract resonances, thus supporting the hypothesis that dynamic vocal tract motions and post-production modulation of sound are necessary features of normal song production.

  8. Experimental and density functional theory study of Raman and SERS spectra of 5-amino-2-mercaptobenzimidazole.

    PubMed

    Chen, Yufeng; Yang, Jin; Li, Zonglong; Li, Ran; Ruan, Weidong; Zhuang, Zhiping; Zhao, Bing

    2016-01-15

    Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) simulations were employed to study 5-amino-2-mercaptobenzimidazole (5-A-2MBI) molecules. Ag colloids were used as SERS substrates which were prepared by using hydroxylamine hydrochloride as reducing agent. Raman vibration modes and SERS characteristic peaks of 5-A-2MBI were assigned with the aid of DFT calculations. The molecular electrostatic potential (MEP) of 5-A-2MBI was used to discuss the possible adsorption behavior of 5-A-2MBI on Ag colloids. The spectral analysis showed that 5-A-2MBI molecules were slightly titled via the sulfur atoms adhering to the surfaces of Ag substrates. The obtained SERS spectral intensity decreased when lowering the 5-A-2MBI concentrations. A final detection limit on the concentration of 5×10(-7) mol · L(-1) was gained. SERS proved to be a simple, fast and reliable method for the detection and characterization of 5-A-2MBI molecules.

  9. New perspectives in biomonitoring liver function by means of serum bile acids: experimental and hypothetical biochemical basis.

    PubMed Central

    Franco, G

    1991-01-01

    The functional activity of the liver and the variety of its responses to injury makes the choice of appropriate tests of function a difficult task. Because of the highly efficient uptake of bile acids by the normal hepatocyte, the determination of serum bile acid (SBA) concentration has been proposed as a test to detect early changes of liver function not associated with cytotoxicity. Several biomonitoring studies have been carried out on subjects occupationally exposed to hepatotoxic substances, by evaluating SBAs as indicators of early liver dysfunction. Even though these studies are not exactly comparable because of the different protocols adopted, most of them show a significant increase in SBA concentrations among the exposed subjects compared with unexposed controls. Furthermore, higher prevalences of subjects with abnormal SBA concentrations occur in those exposed to mixtures of organic solvents. Increased SBA concentrations among the subjects exposed to various xenobiotics have been explained by assuming a change in function of hepatocytes. As regards the nature of the mechanisms involved in the increase in SBA concentrations, recent experimental observations pointed out that some chlorinated aliphatics were able to inhibit cell membrane ATPases and alter cytosolic calcium homeostasis. The lack of any relation, however, between exposure and SBA concentrations remains an important point to clarify and at present prevents the use of measurement of SBA concentrations as an index of effect. PMID:1878313

  10. 2b or Not 2b: Experimental Evolution of Functional Exogenous Sequences in a Plant RNA Virus

    PubMed Central

    Zwart, Mark P.; Ambrós, Silvia; Carrasco, José L.; Elena, Santiago F.

    2017-01-01

    Horizontal gene transfer (HGT) is pervasive in viruses and thought to be a key mechanism in their evolution. On the other hand, strong selective constraints against increasing genome size are an impediment for HGT, rapidly purging horizontally transferred sequences and thereby potentially hindering evolutionary innovation. Here, we explore experimentally the evolutionary fate of viruses with simulated HGT events, using the plant RNA virus Tobacco etch virus (TEV), by separately introducing two functional, exogenous sequences to its genome. One of the events simulates the acquisition of a new function though HGT of a conserved AlkB domain, responsible for the repair of alkylation or methylation damage in many organisms. The other event simulates the acquisition of a sequence that duplicates an existing function, through HGT of the 2b RNA silencing suppressor from Cucumber mosaic virus. We then evolved these two viruses, tracked the maintenance of the horizontally transferred sequences over time, and for the final virus populations, sequenced their genome and measured viral fitness. We found that the AlkB domain was rapidly purged from the TEV genome, restoring fitness to wild-type levels. Conversely, the 2b gene was stably maintained and did not have a major impact on viral fitness. Moreover, we found that 2b is functional in TEV, as it provides a replicative advantage when the RNA silencing suppression domain of HC-Pro is mutated. These observations suggest a potentially interesting role for HGT of short functional sequences in ameliorating evolutionary constraints on viruses, through the duplication of functions. PMID:28137747

  11. 2b or not 2b: Experimental evolution of functional exogenous sequences in a plant RNA virus.

    PubMed

    Willemsen, Anouk; Zwart, Mark P; Ambrós, Silvia; Carrasco, José L; Elena, Santiago F

    2017-01-30

    Horizontal gene transfer (HGT) is pervasive in viruses, and thought to be a key mechanism in their evolution. On the other hand, strong selective constraints against increasing genome size are an impediment for HGT, rapidly purging horizontally transferred sequences and thereby potentially hindering evolutionary innovation. Here we explore experimentally the evolutionary fate of viruses with simulated HGT events, using the plant RNA virus Tobacco etch virus (TEV), by separately introducing two functional, exogenous sequences to its genome. One of the events simulates the acquisition of a new function though HGT of a conserved AlkB domain, responsible for the repair of alkylation or methylation damage in many organisms. The other event simulates the acquisition of a sequence that duplicates an existing function, through HGT of the 2b RNA silencing suppressor from Cucumber mosaic virus (CMV). We then evolved these two viruses, tracked the maintenance of the horizontally transferred sequences over time, and for the final virus populations, sequenced their genome and measured viral fitness. We found that the AlkB domain was rapidly purged from the TEV genome, restoring fitness to wild-type levels. Conversely, the 2b gene was stably maintained and did not have a major impact on viral fitness. Moreover, we found that 2b is functional in TEV, as it provides a replicative advantage when the RNA silencing suppression domain of HC-Pro is mutated. These observations suggest a potentially interesting role for HGT of short functional sequences in ameliorating evolutionary constraints on viruses, through the duplication of functions.

  12. An experimental study of permeability development as a function of crystal-free melt viscosity

    NASA Astrophysics Data System (ADS)

    Lindoo, A.; Larsen, J. F.; Cashman, K. V.; Dunn, A. L.; Neill, O. K.

    2016-02-01

    Permeability development in magmas controls gas escape and, as a consequence, modulates eruptive activity. To date, there are few experimental controls on bubble growth and permeability development, particularly in low viscosity melts. To address this knowledge gap, we have run controlled decompression experiments on crystal-free rhyolite (76 wt.% SiO2), rhyodacite (70 wt.% SiO2), K-phonolite (55 wt.% SiO2) and basaltic andesite (54 wt.% SiO2) melts. This suite of experiments allows us to examine controls on the critical porosity at which vesiculating melts become permeable. As starting materials we used both fine powders and solid slabs of pumice, obsidian and annealed starting materials with viscosities of ∼102 to ∼106 Pas. We saturated the experiments with water at 900° (rhyolite, rhyodacite, and phonolite) and 1025 °C (basaltic andesite) at 150 MPa for 2-72 hrs and decompressed samples isothermally to final pressures of 125 to 10 MPa at rates of 0.25-4.11 MPa/s. Sample porosity was calculated from reflected light images of polished charges and permeability was measured using a bench-top gas permeameter and application of the Forchheimer equation to estimate both viscous (k1) and inertial (k2) permeabilities. Degassing conditions were assessed by measuring dissolved water contents using micro-Fourier-Transform Infrared (μ-FTIR) techniques. All experiment charges are impermeable below a critical porosity (ϕc) that varies among melt compositions. For experiments decompressed at 0.25 MPa/s, we find the percolation threshold for rhyolite is 68.3 ± 2.2 vol.%; for rhyodacite is 77.3 ± 3.8 vol.%; and for K-phonolite is 75.6 ± 1.9 vol.%. Rhyolite decompressed at 3-4 MPa/s has a percolation threshold of 74 ± 1.8 vol.%. These results are similar to previous experiments on silicic melts and to high permeability thresholds inferred for silicic pumice. All basaltic andesite melts decompressed at 0.25 MPa/s, in contrast, have permeabilities below the detection

  13. Thermodynamic prediction of glycine polymerization as a function of temperature and pH consistent with experimentally obtained results.

    PubMed

    Kitadai, Norio

    2014-04-01

    Prediction of the thermodynamic behaviors of biomolecules at high temperature and pressure is fundamental to understanding the role of hydrothermal systems in the origin and evolution of life on the primitive Earth. However, available thermodynamic dataset for amino acids, essential components for life, cannot represent experimentally observed polymerization behaviors of amino acids accurately under hydrothermal conditions. This report presents the thermodynamic data and the revised HKF parameters for the simplest amino acid "Gly" and its polymers (GlyGly, GlyGlyGly and DKP) based on experimental thermodynamic data from the literature. Values for the ionization states of Gly (Gly(+) and Gly(-)) and Gly peptides (GlyGly(+), GlyGly(-), GlyGlyGly(+), and GlyGlyGly(-)) were also retrieved from reported experimental data by combining group additivity algorithms. The obtained dataset enables prediction of the polymerization behavior of Gly as a function of temperature and pH, consistent with experimentally obtained results in the literature. The revised thermodynamic data for zwitterionic Gly, GlyGly, and DKP were also used to estimate the energetics of amino acid polymerization into proteins. Results show that the Gibbs energy necessary to synthesize a mole of peptide bond is more than 10 kJ mol(-1) less than previously estimated over widely various temperatures (e.g., 28.3 kJ mol(-1) → 17.1 kJ mol(-1) at 25 °C and 1 bar). Protein synthesis under abiotic conditions might therefore be more feasible than earlier studies have shown.

  14. Experimental Study of the Convergence of Two-Point Cross-Correlation Toward the Green's Function

    NASA Astrophysics Data System (ADS)

    Gouedard, P.; Roux, P.; Campillo, M.; Verdel, A.; Campman, X.

    2007-12-01

    It has been shown theoretically by several authors that cross-correlation of the seismic motion recorded at two points could yield the Green's Function (GF) between these points. Convergence of cross-correlations toward the GF depends on sources positions and/or the nature of the wavefield. Direct waves from an even distribution of sources can be used to retrieve the GF. On the other hand, in an inhomogeneous medium, recording the diffuse field (coda) is theoretically sufficient to retrieve the GF whatever the sources distribution is. Since none of these two conditions (even distribution of sources or a perfectly diffuse field) is satisfied in practice, the question of convergence toward the GF has to be investigated with real data. A 3D exploration survey with sources and receivers on a dense grid offers such an opportunity. We used a high- resolution survey recorded by Petroleum Development Oman in North Oman. The data have been obtained in a 1x1~km area covered with 1600 geophones located on a 25x25~m-cell grid. Records are 4-seconds long. A unique feature of this survey is that vibrators (working in the [8-120~Hz] frequency band), were located on a similar grid shifted with respect to the receiver grid by half a cell (12.5~m) in both directions. This allows us to compare estimated GF's with measured direct waves (GF's) between the geophones. The shallow subsurface is highly heterogeneous and records include seismic coda. From this dataset, we selected two receiver locations (Ra and Rb) distant from d=158~m. We used both different sets of source locations and time windows to compute the cross-correlation between these two receivers. Then we compared the derivatives of correlation functions with the actual GF measured in Rb (resp.~Ra) for a source close to Ra (resp.~Rb). By doing so, we show the actual influence of source locations and scattering (governed by the records' selected time window) on the Signal-to-Noise Ratio (SNR) of the reconstructed GF. When using

  15. Using experimental manipulation to assess the roles of leaf litter in the functioning of forest ecosystems.

    PubMed

    Sayer, Emma J

    2006-02-01

    The widespread use of forest litter as animal bedding in central Europe for many centuries gave rise to the first litter manipulation studies, and their results demonstrated that litter and its decomposition are a vital part of ecosystem function. Litter plays two major roles in forest ecosystems: firstly, litterfall is an inherent part of nutrient and carbon cycling, and secondly, litter forms a protective layer on the soil surface that also regulates microclimatic conditions. By reviewing 152 years of litter manipulation experiments, I show that the effects of manipulating litter stem from changes in one, or both, of these two functions, and interactions between the variables influenced by the accumulation of litter can result in feedback mechanisms that may intensify treatment effects or mask responses, making the interpretation of results difficult.Long-term litter removal increased soil bulk density, overland flow, erosion, and temperature fluctuations and upset the soil water balance, causing lower soil water content during dry periods. Soil pH increased or decreased in response to manipulation treatments depending on forest type and initial soil pH, but it is unclear why there was no uniform response. Long-term litter harvesting severely depleted the forests of nutrients. Decreases in the concentrations of available P, Ca, Mg, and K in the soil occurred after only three to five years. The decline in soil N occurred over longer periods of time, and the relative loss was greater in soils with high initial nitrogen concentration. Tree growth declined with long-term litter removal, probably due to lower nutrient availability. Litter manipulation also added or removed large amounts of carbon thereby affecting microbial communities and altering soil respiration rates. Litter manipulation experiments have shown that litter cover acts as a physical barrier to the shoot emergence of small-seeded species; further, the microclimate maintained by the litter layer may be

  16. Alterations in hypothalamic KiSS-1 system in experimental diabetes: early changes and functional consequences.

    PubMed

    Castellano, J M; Navarro, V M; Roa, J; Pineda, R; Sánchez-Garrido, M A; García-Galiano, D; Vigo, E; Dieguez, C; Aguilar, E; Pinilla, L; Tena-Sempere, M

    2009-02-01

    Using long-term streptozotocin (STZ)-treated male rats, we recently proposed that defective function of hypothalamic KiSS-1 system is mechanistically relevant for central hypogonadotropism of uncontrolled diabetes. However, the temporal pattern of such defects and its potential contribution to disturbed gonadotropin secretion in the diabetic female remain so far unexplored. To cover these issues, expression analyses and hormonal tests were conducted in diabetic male (1 wk after STZ; short term) and female (4 wk after STZ; long term) rats. Short-term diabetic males had lower basal testosterone levels and decreased gonadotropin responses to orchidectomy (ORX), which associated with significantly attenuated post-ORX rises of hypothalamic KiSS-1 mRNA. Yet kisspeptin administration to diabetic males was able to acutely elicit supramaximal LH and testosterone responses and normalize post-ORX gonadotropin secretion. Long-term diabetic females showed persistent anestrus and significantly decreased basal gonadotropin levels as well as blunted LH responses to ovariectomy; changes that were linked to lowering of basal and postovariectomy expression of hypothalamic KiSS-1 mRNA. Moreover, despite prevailing gonadotropin suppression, LH responses to acute kisspeptin administration were fully preserved, and even enhanced after its repeated injection, in diabetic females. In sum, our present findings further define the temporal course and mechanistic relevance of altered hypothalamic KiSS-1 system in the hypogonadotropic state of uncontrolled diabetes. Furthermore, our data provide the basis for the potential therapeutic intervention of the KiSS-1 system as adjuvant in the management of disturbed gonadotropin secretion of type 1 diabetes in the female.

  17. Systematic reviews and meta-analyses in spine surgery, neurosurgery and orthopedics: guidelines for the surgeon scientist.

    PubMed

    Phan, Kevin; Mobbs, Ralph J

    2015-12-01

    The research evidence in the realm of surgery is expanding at a rapid pace, and thus corresponds with an increasing need to critically appraise and synthesize the available literature. Particularly in fields such as spine surgery, neurosurgery and orthopedics which traditionally have little Class I randomized clinical data, reviews are important to pool the available evidence on clinical questions which are otherwise difficult to answer. Whilst systematic reviews and meta-analyses have the potential to provide critical and updated surgical evidence to guide clinical decisions, poorly performed analyses and misinterpretation of such reviews may have a detrimental effect on patient care and outcomes. We present a summary of the critical steps in performing a systematic review and meta-analysis, allowing the surgeon scientist to better interpret and perform their own systematic reviews and meta-analyses.

  18. What is New and Innovative in Emergency Neurosurgery? Emerging Diagnostic Technologies Provide Better Care and Influence Outcome: A Specialist Review.

    PubMed

    Zisakis, Athanasios K; Varsos, Vassilios; Exadaktylos, Aristomenis

    2013-01-01

    The development of emergency medical services and especially neurosurgical emergencies during recent decades has necessitated the development of novel tools. Although the gadgets that the neurosurgeon uses today in emergencies give him important help in diagnosis and treatment, we still need new technology, which has rapidly developed. This review presents the latest diagnostic tools, which offer precious help in everyday emergency neurosurgery practice. New ultrasound devices make the diagnosis of haematomas easier. In stroke, the introduction of noninvasive new gadgets aims to provide better treatment to the patient. Finally, the entire development of computed tomography and progress in radiology have resulted in innovative CT scans and angiographic devices that advance the diagnosis, treatment, and outcome of the patent. The pressure on physicians to be quick and effective and to avoid any misjudgement of the patient has been transferred to the technology, with the emphasis on developing new systems that will provide our patients with a better outcome and quality of life.

  19. [Experimental studies on the question of an adjuvant function of bromhexine].

    PubMed

    GOtz, V H

    1975-04-01

    On a possible adjuvant function of a bronchosecretolytic preparation commercially available, N-cyclohexyl-N-methyl-(2-amino-3,5-dibromobenzyl)-amine-hydrochloride (bromhexine, Bisolvon-R), sensibilization tests on 30 rabbits were undertaken. 5 animals received Bisolvon and human albumin as antigen, 5 rabbits human albumin only, 5 rabbits Bisolvon and human lymphocytes, 5 rabbits human lymphocytes only, 5 rabbits Bisolvon alone, and 5 received neither Bisolvon nor any antigen. The techniques in these studies, such as two-dimensional double immunodiffusion in agar gel, lymphocytotoxicity test, mixed lymphocyte culture test, electrophoresis on cellulose-acetate foil were used as well as histologic preparations. It could be ascertained that sensitizing with human albumin and simultaneous application of Bisolvon led to a higher concentration of antibodies against albumin than did sensitizing with human albumin alone. Rabbits sensitized with human lymphocytes showed no obvious difference in their antibody rates whether they had received Bisolvon or not. This applied to cell mediated antibodies as well as to the rate of cytotoxic antibodies against human lymphocytes. Among the histologic findings of spleen, bone marrow showed the morphologic equivalences expected from xenosensitization. Comparing the results of sensitized rabbits with and without Bisolvon there were no positive differences as to intensity and/or type of reactivity to be seen. Liver and kidney showed no considerable pathologic phenomena with the exception of some cases with coccidiosis in the bile ductuli. Concerning the bronchial mucosa, in all rabbits treated with Bisolvon an increase of mucine enriched goblet cells as well as a hypergranulation of different epithelial cell types could be observed. Moreover in all animals, including the controls, an intense lymphatic infilitration in the subepithelial and submucous area was identified. The increased antibody concentration in the sera of animals from

  20. MO-DE-202-02: Advances in Image Registration and Reconstruction for Image-Guided Neurosurgery.

    PubMed

    Siewerdsen, J

    2016-06-01

    At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: (1) Keyvan Farahani, "Image-guided focused ultrasound surgery and therapy" (2) Jeffrey H. Siewerdsen, "Advances in image registration and reconstruction for image-guided neurosurgery" (3) Tina Kapur, "Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite" (4) Raj Shekhar, "Multimodality image-guided interventions: Multimodality for the rest of us" Learning Objectives: 1. Understand the principles and applications of HIFU in surgical ablation. 2. Learn about recent advances in 3D-2D and 3D deformable image registration in support of surgical safety and precision. 3. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. 4. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. 5. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and

  1. Prenatal Intestinal Obstruction Affects the Myenteric Plexus and Causes Functional Bowel Impairment in Fetal Rat Experimental Model of Intestinal Atresia

    PubMed Central

    Khen-Dunlop, Naziha; Sarnacki, Sabine; Victor, Anais; Grosos, Celine; Menard, Sandrine; Soret, Rodolphe; Goudin, Nicolas; Pousset, Maud; Sauvat, Frederique; Revillon, Yann; Cerf-Bensussan, Nadine; Neunlist, Michel

    2013-01-01

    Background Intestinal atresia is a rare congenital disorder with an incidence of 3/10 000 birth. About one-third of patients have severe intestinal dysfunction after surgical repair. We examined whether prenatal gastrointestinal obstruction might effect on the myenteric plexus and account for subsequent functional disorders. Methodology/Principal Findings We studied a rat model of surgically induced antenatal atresia, comparing intestinal samples from both sides of the obstruction and with healthy rat pups controls. Whole-mount preparations of the myenteric plexus were stained for choline acetyltransferase (ChAT) and nitric oxide synthase (nNOS). Quantitative reverse transcription PCR was used to analyze mRNAs for inflammatory markers. Functional motility and permeability analyses were performed in vitro. Phenotypic studies were also performed in 8 newborns with intestinal atresia. In the experimental model, the proportion of nNOS-immunoreactive neurons was similar in proximal and distal segments (6.7±4.6% vs 5.6±4.2%, p = 0.25), but proximal segments contained a higher proportion of ChAT-immunoreactive neurons (13.2±6.2% vs 7.5±4.3%, p = 0.005). Phenotypic changes were associated with a 100-fold lower concentration-dependent contractile response to carbachol and a 1.6-fold higher EFS-induced contractile response in proximal compared to distal segments. Transcellular (p = 0.002) but not paracellular permeability was increased. Comparison with controls showed that modifications involved not only proximal but also distal segments. Phenotypic studies in human atresia confirmed the changes in ChAT expression. Conclusion Experimental atresia in fetal rat induces differential myenteric plexus phenotypical as well as functional changes (motility and permeability) between the two sides of the obstruction. Delineating these changes might help to identify markers predictive of motility dysfunction and to define guidelines for post-surgical care. PMID:23667464

  2. Genetic Linkage of Soil Carbon Pools and Microbial Functions in Subtropical Freshwater Wetlands in Response to Experimental Warming

    PubMed Central

    Wang, Hang; He, Zhili; Lu, Zhenmei; Zhou, Jizhong; Van Nostrand, Joy D.; Xu, Xinhua

    2012-01-01

    Rising climate temperatures in the future are predicted to accelerate the microbial decomposition of soil organic matter. A field microcosm experiment was carried out to examine the impact of soil warming in freshwater wetlands on different organic carbon (C) pools and associated microbial functional responses. GeoChip 4.0, a functional gene microarray, was used to determine microbial gene diversity and functional potential for C degradation. Experimental warming significantly increased soil pore water dissolved organic C and phosphorus (P) concentrations, leading to a higher potential for C emission and P export. Such losses of total organic C stored in soil could be traced back to the decomposition of recalcitrant organic C. Warming preferentially stimulated genes for degrading recalcitrant C over labile C. This was especially true for genes encoding cellobiase and mnp for cellulose and lignin degradation, respectively. We confirmed this with warming-enhanced polyphenol oxidase and peroxidase activities for recalcitrant C acquisition and greater increases in recalcitrant C use efficiency than in labile C use efficiency (average percentage increases of 48% versus 28%, respectively). The relative abundance of lignin-degrading genes increased by 15% under warming; meanwhile, soil fungi, as the primary decomposers of lignin, were greater in abundance by 27%. This work suggests that future warming may enhance the potential for accelerated fungal decomposition of lignin-like compounds, leading to greater microbially mediated C losses than previously estimated in freshwater wetlands. PMID:22923398

  3. Genetic linkage of soil carbon pools and microbial functions in subtropical freshwater wetlands in response to experimental warming.

    PubMed

    Wang, Hang; He, Zhili; Lu, Zhenmei; Zhou, Jizhong; Van Nostrand, Joy D; Xu, Xinhua; Zhang, Zhijian

    2012-11-01

    Rising climate temperatures in the future are predicted to accelerate the microbial decomposition of soil organic matter. A field microcosm experiment was carried out to examine the impact of soil warming in freshwater wetlands on different organic carbon (C) pools and associated microbial functional responses. GeoChip 4.0, a functional gene microarray, was used to determine microbial gene diversity and functional potential for C degradation. Experimental warming significantly increased soil pore water dissolved organic C and phosphorus (P) concentrations, leading to a higher potential for C emission and P export. Such losses of total organic C stored in soil could be traced back to the decomposition of recalcitrant organic C. Warming preferentially stimulated genes for degrading recalcitrant C over labile C. This was especially true for genes encoding cellobiase and mnp for cellulose and lignin degradation, respectively. We confirmed this with warming-enhanced polyphenol oxidase and peroxidase activities for recalcitrant C acquisition and greater increases in recalcitrant C use efficiency than in labile C use efficiency (average percentage increases of 48% versus 28%, respectively). The relative abundance of lignin-degrading genes increased by 15% under warming; meanwhile, soil fungi, as the primary decomposers of lignin, were greater in abundance by 27%. This work suggests that future warming may enhance the potential for accelerated fungal decomposition of lignin-like compounds, leading to greater microbially mediated C losses than previously estimated in freshwater wetlands.

  4. Theoretical and Experimental Investigation of Random Gust Loads Part I : Aerodynamic Transfer Function of a Simple Wing Configuration in Incompressible Flow

    NASA Technical Reports Server (NTRS)

    Hakkinen, Raimo J; Richardson, A S , Jr

    1957-01-01

    Sinusoidally oscillating downwash and lift produced on a simple rigid airfoil were measured and compared with calculated values. Statistically stationary random downwash and the corresponding lift on a simple rigid airfoil were also measured and the transfer functions between their power spectra determined. The random experimental values are compared with theoretically approximated values. Limitations of the experimental technique and the need for more extensive experimental data are discussed.

  5. Isothermal density derivative of S(k) and the triplet correlation function: an experimental study in liquid Kr

    NASA Astrophysics Data System (ADS)

    Fontana, Raffaella; Magli, Renato

    1993-08-01

    Recent accurate measurements performed on liquid Kr have been used to test some of the models proposed in the literature for the triplet correlation function g 3( r, s). It turns out that neither the superposition approximation suggested by Kirkwood (J.P. Hansen and I.R. McDonald, Theory of simple liquids, Academic Press, London, 1986), nor a modification of it which partially takes into account linear density effects (H. Fredrikze, Ph.D. Thesis, Delft, 1985) are able to satisfactorily reproduce the experimental isothermal derivatives of the structure factor. Also the uniform fluid model (P.A. Egelstaff, D.I. Page and C.R.T. Heard, J. Phys. C, 4 (1971) 1453), gives a poor representation especially at lower densities. It is concluded that, in order to correctly describe triplet correlation effects, a full account of the irreducible contributions to g 3( r, s) is necessary.

  6. Subcortical ischemic vascular disease: Roles of oligodendrocyte function in experimental models of subcortical white-matter injury.

    PubMed

    Shindo, Akihiro; Liang, Anna C; Maki, Takakuni; Miyamoto, Nobukazu; Tomimoto, Hidekazu; Lo, Eng H; Arai, Ken

    2016-01-01

    Oligodendrocytes are one of the major cell types in cerebral white matter. Under normal conditions, they form myelin sheaths that encircle axons to support fast nerve conduction. Under conditions of cerebral ischemia, oligodendrocytes tend to die, resulting in white-matter dysfunction. Repair of white matter involves the ability of oligodendrocyte precursors to proliferate and mature. However, replacement of lost oligodendrocytes may not be the only mechanism for white-matter recovery. Emerging data now suggest that coordinated signaling between neural, glial, and vascular cells in the entire neurovascular unit may be required. In this mini-review, we discuss how oligodendrocyte lineage cells participate in signaling and crosstalk with other cell types to underlie function and recovery in various experimental models of subcortical white-matter injury.

  7. Subcortical ischemic vascular disease: Roles of oligodendrocyte function in experimental models of subcortical white-matter injury

    PubMed Central

    Shindo, Akihiro; Liang, Anna C; Maki, Takakuni; Miyamoto, Nobukazu; Tomimoto, Hidekazu; Lo, Eng H

    2016-01-01

    Oligodendrocytes are one of the major cell types in cerebral white matter. Under normal conditions, they form myelin sheaths that encircle axons to support fast nerve conduction. Under conditions of cerebral ischemia, oligodendrocytes tend to die, resulting in white-matter dysfunction. Repair of white matter involves the ability of oligodendrocyte precursors to proliferate and mature. However, replacement of lost oligodendrocytes may not be the only mechanism for white-matter recovery. Emerging data now suggest that coordinated signaling between neural, glial, and vascular cells in the entire neurovascular unit may be required. In this mini-review, we discuss how oligodendrocyte lineage cells participate in signaling and crosstalk with other cell types to underlie function and recovery in various experimental models of subcortical white-matter injury. PMID:25920960

  8. Use of Modern Chemical Protein Synthesis and Advanced Fluorescent Assay Techniques to Experimentally Validate the Functional Annotation of Microbial Genomes

    SciTech Connect

    Kent, Stephen

    2012-07-20

    The objective of this research program was to prototype methods for the chemical synthesis of predicted protein molecules in annotated microbial genomes. High throughput chemical methods were to be used to make large numbers of predicted proteins and protein domains, based on microbial genome sequences. Microscale chemical synthesis methods for the parallel preparation of peptide-thioester building blocks were developed; these peptide segments are used for the parallel chemical synthesis of proteins and protein domains. Ultimately, it is envisaged that these synthetic molecules would be ‘printed’ in spatially addressable arrays. The unique ability of total synthesis to precision label protein molecules with dyes and with chemical or biochemical ‘tags’ can be used to facilitate novel assay technologies adapted from state-of-the art single molecule fluorescence detection techniques. In the future, in conjunction with modern laboratory automation this integrated set of techniques will enable high throughput experimental validation of the functional annotation of microbial genomes.

  9. Exocrine and endocrine testicular function during the treatment of experimental orchitis and nonspecific orchoepididymitis by low-energy laser radiation

    NASA Astrophysics Data System (ADS)

    Reznikov, Leonid L.; Pupkova, Ludmila S.; Bell, H.; Murzin, Alexander G.

    1995-05-01

    Investigations into the biological effects of low-energy laser radiation (LLR) are characterized by a score of challenges, which are due primarily to a cascade of laser-induced and sometimes antagonistic processes. To investigate these processes on various biologic levels, we analyzed local and general effects of LLR on the exocrine and endocrine functions of the accessory sex glands in experimentally induced orchitis and orchoepididymitis in rabbits, and in clinical studies on male patients. The results indicate that LLR may alter the inflammatory response, including the exudative reaction, macrophage migration, and fibroblast activity. Furthermore, LLR may result in changes in serum concentrations of LH, FSH, and ACTH, prolactin, testosterone, cortisol and aldosterone. Some of these changes may be at least partially responsible for the well-known anti-inflammatory effects of LLR.

  10. Cuprizone and piperonyl butoxide, proposed inhibitors of T-cell function, attenuate experimental allergic encephalomyelitis in SJL mice.

    PubMed

    Emerson, M R; Biswas, S; LeVine, S M

    2001-10-01

    Multiple sclerosis (MS) and its animal model, experimental allergic encephalomyelitis (EAE), are autoimmune demyelinating diseases with autoreactive T-cells acting as important mediators of pathogenesis. Cuprizone, a copper chelator, and piperonyl butoxide (PBO), a pesticide synergist, are implicated to inhibit T-cell activation and function. The purpose of this study was to assess whether either of these agents would suppress PLP-peptide-induced EAE in the SJL mouse. Indeed, treatment with cuprizone beginning 1 week prior to disease induction, and PBO administration from days 1 to 9 of EAE, significantly attenuated EAE clinical severity. Furthermore, both agents decreased blood CD4+/CD8+ ratios, and reduced signs of chronic graft vs. host disease (GVHD) indicating attenuation of an immune T-cell response. These results suggest that cuprizone and PBO suppress EAE and use of these agents will provide insights into the mechanisms of T-cell mediated diseases.

  11. Epstein-Barr virus latent membrane protein 2A exacerbates experimental autoimmune encephalomyelitis and enhances antigen presentation function

    PubMed Central

    Chang, Rhoda A.; Miller, Stephen D.; Longnecker, Richard

    2012-01-01

    Multiple sclerosis (MS) is an inflammatory, autoimmune disease of the central nervous system. The cause of MS is still unknown but epidemiological and immunological studies have implicated Epstein-Barr virus (EBV), which infects B cells, as a possible etiological agent involved in disease. Of particular interest is EBV latent membrane protein 2A (LMP2A) because previous studies have demonstrated that LMP2A enhances the expansion and differentiation of B cells upon antigen stimulation, revealing a potential contribution of this protein in autoimmunity. Since B cells are thought to contribute to MS, we examined the role of LMP2A in the animal model experimental autoimmune encephalomyelitis (EAE). In this model, transgenic mice in which B cells express LMP2A show increased severity and incidence of disease. This difference was not due to lymphocyte recruitment into the CNS or differences in T cell activation, rather, we show that LMP2A enhances antigen presentation function. PMID:22616025

  12. Compressibility and hardness of Co-based bulk metallic glass: A combined experimental and density functional theory study

    SciTech Connect

    Wang Jianfeng; Li Ran; Xu Tao; Li Yan; Liu Zengqian; Huang Lu; Hua Nengbin; Zhang Tao; Xiao Ruijuan; Li Gong; Li Yanchun

    2011-10-10

    An incompressible Co{sub 54}Ta{sub 11}B{sub 35} bulk metallic glass (BMG) was investigated using in situ high-pressure synchrotron diffraction and nanoindendation. The elastic constants were deduced from the experiments based on the isotropic model. The Vickers hardness was measured to be 17.1 GPa. The elastic moduli and hardness are the highest values known in BMGs. The theoretically calculated elastic properties by density-functional study were well consistent with experimental measurements. The analysis of charge density and bonding character indicates the covalent character of Co-B and B-B bonds, underlying the unusually high elastic modulus and hardness in this material.

  13. Structural and optical properties of Cu doped SnO2 nanoparticles: An experimental and density functional study

    NASA Astrophysics Data System (ADS)

    Chetri, Pawan; Saikia, Bhamyarswa; Choudhury, Amarjyoti

    2013-06-01

    The paper investigates, both theoretically and experimentally, the structural and optical changes in SnO2 system brought about by introduction of Cu in a SnO2 system. On the experimental front, a cost effective sol-gel technique is used to prepare hexagonal shaped Cu doped SnO2 nanoparticles. The prepared pristine SnO2 nanoparticle is found to be of random shape by transmission electron microscope (TEM) studies. A structural and morphological study is carried out using X-ray diffraction and TEM techniques. The different phonon interaction in the system is observed by Raman spectroscopy while electron paramagnetic resonance and UV-Visible spectroscopy confirms the presence of Cu in 2+ state. First principle calculations have been performed using "density functional theory"-based MedeA Vienna Ab Initio Simulation package on a SnO2 system where Cu is introduced. The introduction of Cu in the SnO2 system brings distortion which is corroborated by the variation in the corresponding bond lengths. The Density of State calculation of Sn16O32 and CuSn15O32 is also performed. Finally, a correlation is established between the experiment and the theory.

  14. Assessment of Gaussian-3 and density-functional theories on the G3/05 test set of experimental energies.

    PubMed

    Curtiss, Larry A; Redfern, Paul C; Raghavachari, Krishnan

    2005-09-22

    The G3/99 test set [L. A. Curtiss, K. Raghavachari, P. C. Redfern, and J. A. Pople, J. Chem. Phys. 112, 7374 (2000)] of thermochemical data for validation of quantum chemical methods is expanded to include 78 additional energies including 14 enthalpies of formation of the first- and second-row nonhydrogen molecules, 58 energies of molecules containing the third-row elements K, Ca, and Ga-Kr, and 6 hydrogen-bonded complexes. The criterion used for selecting the additional systems is the same as before, i.e., experimental uncertainties less than +/- 1 kcal/mol. This new set, referred to as the G3/05 test set, has a total of 454 energies. The G3 and G3X theories are found to have mean absolute deviations of 1.13 and 1.01 kcal/mol, respectively, when applied to the G3/05 test set. Both methods have larger errors for the nonhydrogen subset of 79 species for which they have mean absolute deviations of 2.10 and 1.64 kcal/mol, respectively. On all of the other types of energies the G3 and G3X methods are very reliable. The G3/05 test set is also used to assess density-functional methods including a series of new functionals. The most accurate functional for the G3/05 test set is B98 with a mean absolute deviation of 3.33 kcal/mol, compared to 4.14 kcal/mol for B3LYP. The latter functional has especially large errors for larger molecules with a mean absolute deviation of 9 kcal/mol for molecules having 28 or more valence electrons. For smaller molecules B3LYP does as well or better than B98 and the other functionals. It is found that many of the density-functional methods have significant errors for the larger molecules in the test set.

  15. 2,3-Pyridine dicarboxylic acid functionalized gold nanoparticles: Insight into experimental conditions for Cr(3+) sensing.

    PubMed

    Shaikh, Ruqaya; Memon, Najma; Solangi, Amber R; Shaikh, Huma I; Agheem, Muhammad Hassan; Ali, Syed Abid; Shah, Muhammad Raza; Kandhro, Aftab

    2017-02-15

    Selectivity of gold nanoparticles (AuNPs) depends upon surface functionality; small changes in structure or concentration bring significant changes in the behavior of AuNPs. In this study, citrate-capped AuNPs were functionalized with ortho-dicarboxylate substituted pyridine (2,3-PDCA) and detailed studies on experimental conditions were carried out to check the stability of AuNPs and response for Cr(3+). Stability of PDCA-AuNPs was found sensitive to the pH, ionic strength of buffer and its type. Capping behavior of PDCA on C-AuNPs was examined by FTIR spectroscopy. Surface morphology and size of synthesized AuNPs were confirmed by AFM, XRD, and DLS techniques where particles were found 11nm in size, monodisperse and spherical in shape. Interaction of stabilized AuNPs was tested with various metal ions; where Cr(3+) induced the changes in localized surface plasmon band (LSPR) of PDCA-AuNPs which leads to a color change from wine red to violet blue. The phenomenon is explained as cooperative effect of citrate and pyridine nitrogen on surface of AuNPs in contrary to meta-dicarboxylate substituted pyridine derivatives. Further, under optimized and controlled conditions Cr(3+) shows linear response with decrease in absorbance at LSPR intensity of AuNPs (518nm). Moreover, to demonstrate the applicability of method, Cr(3+) was determined in the presence of Cr (VI) which shows 96% recovery.

  16. Experimental Determination of the Dynamic Hydraulic Transfer Function for the J-2X Oxidizer Turbopump. Part One; Methodology

    NASA Technical Reports Server (NTRS)

    Zoladz, Tom; Patel, Sandeep; Lee, Erik; Karon, Dave

    2011-01-01

    An advanced methodology for extracting the hydraulic dynamic pump transfer matrix (Yp) for a cavitating liquid rocket engine turbopump inducer+impeller has been developed. The transfer function is required for integrated vehicle pogo stability analysis as well as optimization of local inducer pumping stability. Laboratory pulsed subscale waterflow test of the J-2X oxygen turbo pump is introduced and our new extraction method applied to the data collected. From accurate measures of pump inlet and discharge perturbational mass flows and pressures, and one-dimensional flow models that represents complete waterflow loop physics, we are able to derive Yp and hence extract the characteristic pump parameters: compliance, pump gain, impedance, mass flow gain. Detailed modeling is necessary to accurately translate instrument plane measurements to the pump inlet and discharge and extract Yp. We present the MSFC Dynamic Lump Parameter Fluid Model Framework and describe critical dynamic component details. We report on fit minimization techniques, cost (fitness) function derivation, and resulting model fits to our experimental data are presented. Comparisons are made to alternate techniques for spatially translating measurement stations to actual pump inlet and discharge.

  17. Estimation of the neuromotor system functional state after sciatic nerve neurorrhaphy in experimental conditions of intravenous laser irradiation of blood

    NASA Astrophysics Data System (ADS)

    Nechipurenko, N. I.; Tanin, Leonid V.; Antonov, Ignatii P.; Vasilevskaya, Lyudmila A.; Vlasyuk, P. A.

    1996-12-01

    The speckle-optical methods and the methods of electroneuromyography were used to study the myotonus, the contractional activity of leg muscles and the neuromotor system functional state in intact rabbits and 3 months after the sciatic nerve (SN) neurorrhaphy in conditions of intravenous laser irradiation of blood (ILIB). The blood of animals was exposed to laser radiation with the help of a quartz-polymeric light guide, which has been inserted into the earvein the next day after SN stitching. The radiation power at the light guide output was 2-2.5 mW. Two courses of treatment with a two-week interval have been conducted. It has been established from the speckle-optical study data that ILIB increases the contractional activity of skeletal muscles in animals. The ILIB-therapy after the SN neurorrhaphy normalizes the latent period of M-response and neural cation potential. A tendancy has been revealed to an increase in impulse conduction velocity in motor nerve fibers and in maximal amplitude of the neural action potential. Thus, the ILIB-therapy after SN trauma improves the neuromotor system functional state in experimental animals in the early reinnervation period.

  18. 2,3-Pyridine dicarboxylic acid functionalized gold nanoparticles: Insight into experimental conditions for Cr3 + sensing

    NASA Astrophysics Data System (ADS)

    Shaikh, Ruqaya; Memon, Najma; Solangi, Amber R.; Shaikh, Huma I.; Agheem, Muhammad Hassan; Ali, Syed Abid; Shah, Muhammad Raza; Kandhro, Aftab

    2017-02-01

    Selectivity of gold nanoparticles (AuNPs) depends upon surface functionality; small changes in structure or concentration bring significant changes in the behavior of AuNPs. In this study, citrate-capped AuNPs were functionalized with ortho-dicarboxylate substituted pyridine (2,3-PDCA) and detailed studies on experimental conditions were carried out to check the stability of AuNPs and response for Cr3 +. Stability of PDCA-AuNPs was found sensitive to the pH, ionic strength of buffer and its type. Capping behavior of PDCA on C-AuNPs was examined by FTIR spectroscopy. Surface morphology and size of synthesized AuNPs were confirmed by AFM, XRD, and DLS techniques where particles were found 11 nm in size, monodisperse and spherical in shape. Interaction of stabilized AuNPs was tested with various metal ions; where Cr3 + induced the changes in localized surface plasmon band (LSPR) of PDCA-AuNPs which leads to a color change from wine red to violet blue. The phenomenon is explained as cooperative effect of citrate and pyridine nitrogen on surface of AuNPs in contrary to meta-dicarboxylate substituted pyridine derivatives. Further, under optimized and controlled conditions Cr3 + shows linear response with decrease in absorbance at LSPR intensity of AuNPs (518 nm). Moreover, to demonstrate the applicability of method, Cr3 + was determined in the presence of Cr (VI) which shows 96% recovery.

  19. Effects of experimentally elevated traffic noise on nestling white-crowned sparrow stress physiology, immune function and life history.

    PubMed

    Crino, Ondi L; Johnson, Erin E; Blickley, Jessica L; Patricelli, Gail L; Breuner, Creagh W

    2013-06-01

    Roads have been associated with behavioral and physiological changes in wildlife. In birds, roads decrease reproductive success and biodiversity and increase physiological stress. Although the consequences of roads on individuals and communities have been well described, the mechanisms through which roads affect birds remain largely unexplored. Here, we examine one mechanism through which roads could affect birds: traffic noise. We exposed nestling mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) to experimentally elevated traffic noise for 5 days during the nestling period. Following exposure to traffic noise we measured nestling stress physiology, immune function, body size, condition and survival. Based on prior studies, we expected the traffic noise treatment to result in elevated stress hormones (glucocorticoids), and declines in immune function, body size, condition and survival. Surprisingly, nestlings exposed to traffic noise had lower glucocorticoid levels and improved condition relative to control nests. These results indicate that traffic noise does affect physiology and development in white-crowned sparrows, but not at all as predicted. Therefore, when evaluating the mechanisms through which roads affect avian populations, other factors (e.g. edge effects, pollution and mechanical vibration) may be more important than traffic noise in explaining elevated nestling stress responses in this species.

  20. Thiol Functionalized Silica-Mixed Matrix Membranes for Silver Capture from Aqueous Solutions: Experimental Results and Modeling

    PubMed Central

    Ladhe, A. R.; Frailie, P.; Hua, D.; Darsillo, M.; Bhattacharyya, D.

    2009-01-01

    The study deals with an aqueous phase application of Mixed Matrix Membranes (MMMs) for silver ion (Ag+) capture. Silica particles were functionalized with 3-mercaptopropyltrimethoxy silane (MPTMS) to introduce free thiol (-SH) groups on the surface. The particles were used as the dispersed phase in the polysulfone or cellulose acetate polymer matrix. The membranes were prepared by the phase inversion method to create more open and interconnected porous structures suitable for liquid phase applications. The effects of the silica properties such as particle size, specific surface area, and porous/nonporous morphology on the silver ion capture capacity were studied. It was demonstrated that the membranes are capable of selectively capturing silver from a solution containing significant concentrations of other metal ions like Ca2+. The membranes were studied to quantify the dynamic capacity for silver ion capture and its dependence on residence time through the adjustment of transmembrane pressure. The thiol-Ag+ interaction was quantified with Quartz Crystal Microbalance in a continuous flow mode experiment and the observations were compared with the membrane results. One dimensional unsteady state model with overall volumetric mass transfer coefficient was developed and solved to predict the silver concentration in the liquid phase and the solid silica phase along the membrane thickness at varying time. The breakthrough data predicted using the model is comparable with the experimental observations. The study demonstrates successful application of the functionalized silica-mixed matrix membranes for selective aqueous phase Ag+ capture with high capacity at low transmembrane pressures. The technique can be easily extended to other applications by altering the functionalized groups on the silica particles. PMID:20098490

  1. Development of the ultra-miniaturized Inertial Measurement Unit WB3 for objective skill analysis and assessment in neurosurgery: preliminary results.

    PubMed

    Zecca, Massimiliano; Sessa, Salvatore; Lin, Zhuohua; Suzuki, Takashi; Sasaki, Tomoya; Itoh, Kazuko; Iseki, Hiroshi; Takanishi, Atsuo

    2009-01-01

    In recent years there has been an ever increasing amount of research and development of technologies and methodologies aimed at improving the safety of advanced surgery. In this context, several training methods and metrics have been proposed, in particular for laparoscopy, both to improve the surgeon's abilities and also to assess her/his skills. For neurosurgery, however, the extremely small movements and sizes involved have prevented until now the development of similar methodologies and systems. In this paper we present the development of the ultra-miniaturized Inertial Measurement Unit WB3 (at present the smallest, lightest, and best performing in the world) for practical application in neurosurgery as skill assessment tool. This paper presents the feasibility study for quantitative discrimination of movements of experienced surgeons and beginners in a simple pick and place scenario.

  2. Management of Subarachnoid Hemorrhage in Two Important Italian Political Leaders: A Paradigm of Ethical and Technological Evolution of Neurosurgery During the Past Half-Century.

    PubMed

    Longatti, Pierluigi; Giombelli, Ermanno; Pavesi, Giacomo; Carteri, Alessandro; Feletti, Alberto

    2016-08-01

    For a curious and extraordinary coincidence, 5 of the 7 most relevant leaders of the Italian Communist Party (Partito Comunista Italiano, which was established in 1921, has been the biggest Communist Party in Western Countries) suffered a cerebral stroke. Cerebrovascular diseases afflicted also Stalin and Lenin, and a number of Presidents of the United States. We present the stories of 2 important Italian political leaders who shared both the leadership role of the major left Italian Party and the dramatic experience of a subarachnoid hemorrhage. Retracing their medical incidents, separated by 50 years of history, we show how a fatal medical disease has become neurosurgical and successfully cured thanks to the advances of neurosurgery, neuroradiology, and hospital organization. A neurologic disease that was disgraceful 50 years ago has lost any disquieting and embarrassing significance in the present time to the light of evolution of vascular neurosurgery.

  3. Essentials of research methods in neurosurgery and allied sciences for research, appraisal and application of scientific information to patient care (Part I)

    PubMed Central

    Esene, Ignatius N.; El-Shehaby, Amr M.; Baeesa, Saleh S.

    2016-01-01

    Every neurosurgeon ought to be acquainted with the basics of research methods to enhance the comprehension of the research process and critical appraisal procedures of a scientific write-up. This in turn will ensure the appropriate application of scientific knowledge to patient care. Recent publications reveal that a significant proportion of articles published in neurosurgery are mislabeled with dire consequences on the sorting and indexing of evidence. Furthermore, many clinicians report that they feel unqualified to read the medical literature critically hence, it is for this reason that we conducted this review. Herein, we present a simple algorithm to facilitate the comprehension of research methods, as well as elucidate on the anatomy of common study designs in neurosurgery. Illustrative examples are provided when necessary. Understanding research methods and the critical analysis of published reports of clinical investigation is a fundamental skill of the physician to enable the incorporation of new clinical knowledge to practice PMID:27094519

  4. In situ synthesis and surface functionalization of gold nanoparticles with curcumin and their antioxidant properties: an experimental and density functional theory investigation

    NASA Astrophysics Data System (ADS)

    Singh, Dheeraj K.; Jagannathan, Ramya; Khandelwal, Puneet; Abraham, Priya Mary; Poddar, Pankaj

    2013-02-01

    Curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is an active component of turmeric; it is responsible for its characteristic yellow color and therapeutic potential, but its poor bioavailability remains a major challenge. In order to improve the bioavailability of curcumin, various approaches have been used. One of the possible approaches to increase the bioavailability of curcumin is its conjugation on the surface of metal nanoparticles. Therefore, in the present study, we report the binding of curcumin on the surface of gold nanoparticles (AuNPs). The AuNPs were synthesized by the direct reduction of HAuCl4 using curcumin in the aqueous phase, without the use of any other reducing agents. We found that curcumin acts both as a reducing and capping agent, stabilizing the gold sol for many months. Moreover, these curcumin-capped AuNPs also show good antioxidant activity which was confirmed by the DPPH (2,2-diphenyl-l-picrylhydrazyl) radical test. Thus, the surface functionalization of AuNPs with curcumin may pave a new way of using the curcuminoids towards possible drug delivery and therapeutics. Apart from the experimental study, a detailed quantum chemical calculation using density functional theory (DFT) has been performed, in order to investigate the formation of a complex of curcumin with Au3+ ions in different possible conformational isomeric forms. Our theoretical calculations indicate the evidence of electron transfer from curcumin into the Au center and essentially indicate that as a consequence of complexation, Au3+ ions are reduced to Au0. Our theoretical results also propose that it is the breakage of intramolecular H-bonding that probably leads to the increased availability of curcumin in the presence of gold ions and water molecules.Curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is an active component of turmeric; it is responsible for its characteristic yellow color and therapeutic

  5. Generating information-rich high-throughput experimental materials genomes using functional clustering via multitree genetic programming and information theory.

    PubMed

    Suram, Santosh K; Haber, Joel A; Jin, Jian; Gregoire, John M

    2015-04-13

    High-throughput experimental methodologies are capable of synthesizing, screening and characterizing vast arrays of combinatorial material libraries at a very rapid rate. These methodologies strategically employ tiered screening wherein the number of compositions screened decreases as the complexity, and very often the scientific information obtained from a screening experiment, increases. The algorithm used for down-selection of samples from higher throughput screening experiment to a lower throughput screening experiment is vital in achieving information-rich experimental materials genomes. The fundamental science of material discovery lies in the establishment of composition-structure-property relationships, motivating the development of advanced down-selection algorithms which consider the information value of the selected compositions, as opposed to simply selecting the best performing compositions from a high throughput experiment. Identification of property fields (composition regions with distinct composition-property relationships) in high throughput data enables down-selection algorithms to employ advanced selection strategies, such as the selection of representative compositions from each field or selection of compositions that span the composition space of the highest performing field. Such strategies would greatly enhance the generation of data-driven discoveries. We introduce an informatics-based clustering of composition-property functional relationships using a combination of information theory and multitree genetic programming concepts for identification of property fields in a composition library. We demonstrate our approach using a complex synthetic composition-property map for a 5 at. % step ternary library consisting of four distinct property fields and finally explore the application of this methodology for capturing relationships between composition and catalytic activity for the oxygen evolution reaction for 5429 catalyst compositions in a

  6. MAOA-uVNTR genotype predicts interindividual differences in experimental aggressiveness as a function of the degree of provocation.

    PubMed

    Kuepper, Yvonne; Grant, Phillip; Wielpuetz, Catrin; Hennig, Juergen

    2013-06-15

    The MAOA-uVNTR has been suggested to play a role regarding aggression, however, results are inconsistent. We aimed at further elucidating potential effects of the MAOA-uVNTR on aggressiveness with respect to potential modulators: sex, experimental vs. trait aggressiveness and type of aggressiveness (proactive vs. reactive aggressiveness). We tested 239 healthy young adults (88 men/151 women). Participants were genotyped for the MAOA-uVNTR and performed a modified version of a competitive reaction time task - a commonly used and well established tool to elicit and measure aggressiveness. Furthermore, they completed a self-report scale measuring trait aggressiveness. We found a main effect of MAOA-uVNTR on a measure of reactive aggressiveness for both men and women, whereby the low-activity alleles of the MAOA-uVNTR were associated with substantially increased aggressive reactions (p<.05). This effect was unique for reactive aggressiveness. Measures of proactive aggressiveness or self reports were not associated with the MAOA-uVNTR-genotype. Our data are in line with earlier studies and indicate the MAOA-uVNTR-genotype to be specifically associated with measures of reactive impulsive experimental aggressiveness in healthy men and women. Furthermore the association between the MAOA-uVNTR genotype and aggressive responses increases in a fashion linear to the degree of provocation. This indicates that the low-functional alleles of the MAOA-uVNTR are not associated with increased aggressive behavior per se, but rather with an increased aggressive reactivity to provocation.

  7. In situ synthesis and surface functionalization of gold nanoparticles with curcumin and their antioxidant properties: an experimental and density functional theory investigation.

    PubMed

    Singh, Dheeraj K; Jagannathan, Ramya; Khandelwal, Puneet; Abraham, Priya Mary; Poddar, Pankaj

    2013-03-07

    Curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is an active component of turmeric; it is responsible for its characteristic yellow color and therapeutic potential, but its poor bioavailability remains a major challenge. In order to improve the bioavailability of curcumin, various approaches have been used. One of the possible approaches to increase the bioavailability of curcumin is its conjugation on the surface of metal nanoparticles. Therefore, in the present study, we report the binding of curcumin on the surface of gold nanoparticles (AuNPs). The AuNPs were synthesized by the direct reduction of HAuCl(4) using curcumin in the aqueous phase, without the use of any other reducing agents. We found that curcumin acts both as a reducing and capping agent, stabilizing the gold sol for many months. Moreover, these curcumin-capped AuNPs also show good antioxidant activity which was confirmed by the DPPH (2,2-diphenyl-l-picrylhydrazyl) radical test. Thus, the surface functionalization of AuNPs with curcumin may pave a new way of using the curcuminoids towards possible drug delivery and therapeutics. Apart from the experimental study, a detailed quantum chemical calculation using density functional theory (DFT) has been performed, in order to investigate the formation of a complex of curcumin with Au(3+) ions in different possible conformational isomeric forms. Our theoretical calculations indicate the evidence of electron transfer from curcumin into the Au center and essentially indicate that as a consequence of complexation, Au(3+) ions are reduced to Au(0). Our theoretical results also propose that it is the breakage of intramolecular H-bonding that probably leads to the increased availability of curcumin in the presence of gold ions and water molecules.

  8. Experimental Determination of the 1 Sigma(+) State Electric-Dipole-Moment Function of Carbon Monoxide up to a Large Internuclear Separation

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.; Farreng, R.; Guelachvili, G.; Rossetti, C.; Urban, W.

    1984-01-01

    Experimental intensity information is combined with numerically obtained vibrational wave functions in a nonlinear least squares fitting procedure to obtain the ground electronic state electric-dipole-moment function of carbon monoxide valid in the range of nuclear oscillation (0.87 to 1.01 A) of about the V = 38th vibrational level. Mechanical anharmonicity intensity factors, H, are computed from this function for delta V + = 1, 2, 3, with or = to 38.