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Sample records for nerve head blood

  1. Quantitative OCT angiography of optic nerve head blood flow

    PubMed Central

    Jia, Yali; Morrison, John C.; Tokayer, Jason; Tan, Ou; Lombardi, Lorinna; Baumann, Bernhard; Lu, Chen D.; Choi, WooJhon; Fujimoto, James G.; Huang, David

    2012-01-01

    Optic nerve head (ONH) blood flow may be associated with glaucoma development. A reliable method to quantify ONH blood flow could provide insight into the vascular component of glaucoma pathophysiology. Using ultrahigh-speed optical coherence tomography (OCT), we developed a new 3D angiography algorithm called split-spectrum amplitude-decorrelation angiography (SSADA) for imaging ONH microcirculation. In this study, a method to quantify SSADA results was developed and used to detect ONH perfusion changes in early glaucoma. En face maximum projection was used to obtain 2D disc angiograms, from which the average decorrelation values (flow index) and the percentage area occupied by vessels (vessel density) were computed from the optic disc and a selected region within it. Preperimetric glaucoma patients had significant reductions of ONH perfusion compared to normals. This pilot study indicates OCT angiography can detect the abnormalities of ONH perfusion and has the potential to reveal the ONH blood flow mechanism related to glaucoma. PMID:23243564

  2. Optic Nerve Head Blood Flow Autoregulation during Changes in Arterial Blood Pressure in Healthy Young Subjects

    PubMed Central

    Boltz, Agnes; Told, Reinhard; Napora, Katarzyna J.; Palkovits, Stefan; Werkmeister, René M.; Schmidl, Doreen; Popa-Cherecheanu, Alina; Garhöfer, Gerhard; Schmetterer, Leopold

    2013-01-01

    Aim In the present study the response of optic nerve head blood flow to an increase in ocular perfusion pressure during isometric exercise was studied. Based on our previous studies we hypothesized that subjects with an abnormal blood flow response, defined as a decrease in blood flow of more than 10% during or after isometric exercise, could be identified. Methods A total of 40 healthy subjects were included in this study. Three periods of isometric exercise were scheduled, each consisting of 2 minutes of handgripping. Optic nerve head blood flow was measured continuously before, during and after handgripping using laser Doppler flowmetry. Blood pressure was measured non-invasively in one-minute intervals. Intraocular pressure was measured at the beginning and the end of the measurements and ocular perfusion pressure was calculated as 2/3*mean arterial pressure –intraocular pressure. Results Isometric exercise was associated with an increase in ocular perfusion pressure during all handgripping periods (p < 0.001). By contrast no change in optic nerve head blood flow was seen. However, in a subgroup of three subjects blood flow showed a consistent decrease of more than 10% during isometric exercise although their blood pressure values increased. In addition, three other subjects showed a consistent decline of blood flow of more than 10% during the recovery periods. Conclusion Our data confirm previous results indicating that optic nerve head blood flow is autoregulated during an increase in perfusion pressure. In addition, we observed a subgroup of 6 subjects (15%) that showed an abnormal response, which is in keeping with our previous data. The mechanisms underlying this abnormal response remain to be shown. PMID:24324774

  3. Variations of blood flow at optic nerve head induced by sinusoidal flicker stimulation in cats.

    PubMed

    Vo Van Toi; Riva, C E

    1995-01-01

    1. The present investigation explored, in thirty-four anaesthetized cats, the blood flow changes at the optic nerve head elicited by sinusoidally modulated photic stimuli. 2. The stimuli were achromatic, diffuse and had 30 deg diameter field size; the stimulus frequency was varied from 0 to 100 Hz, modulation depth from 0 to 100% and mean retinal illuminance up to 50,000 trolands (td); the blood flow was measured with a near-infrared (810 nm) laser Doppler flowmeter. 3. At various frequencies, modulation depths and mean retinal illuminance, sinusoidal flicker stimulation always caused an increase in blood flow at the optic nerve head relative to steady stimulation. 4. The frequency response and temporal contrast sensitivity function of the blood flow changes had a bandpass shape; the high-frequency slope of the frequency response was 3 decades (dec) per decade and that of the temporal contrast sensitivity function was 1.7 dec per dec, close to the slope for cat 'on' ganglion cells (2.6 dec per dec). 5. In most cats, the magnitude of the increase in blood flow was a sigmoidal function of modulation depth; in the remainder, the relationship was close to linear. 6. The threshold of blood flow changes varied with respect to mean retinal illuminance similar to Ferry-Porter's law and the photopic linear slope was 50 Hz dec-1. 7. In comparison with reported psychophysical and electrophysiological responses elicited by similar stimulations, the results of the present study resemble more those obtained from ganglion cells than those from electroretinograms, visual-evoked potentials and psychophysics. It is suggested that the blood flow changes at the optic nerve head are induced by the activity of ganglion cells. PMID:7730982

  4. Static Blood Flow Autoregulation in the Optic Nerve Head in Normal and Experimental Glaucoma

    PubMed Central

    Wang, Lin; Burgoyne, Claude F.; Cull, Grant; Thompson, Simon; Fortune, Brad

    2014-01-01

    Purpose. To characterize the static blood flow autoregulation in the optic nerve head (ONH), and to investigate its role in hemodynamic changes in experimental glaucoma (EG). Methods. Unilateral elevation of intraocular pressure (IOP) was induced in 15 adult rhesus macaques by laser treatment to the trabecular meshwork. Prior to and after laser treatment, retinal nerve fiber layer thickness (RNFLT) was assessed, biweekly, by spectral-domain optical coherence tomography. Optic nerve head static autoregulation was assessed by determining the percentage blood flow (BF) change after the IOP was acutely increased from 10 to 30, 40, or 50 mm Hg manometrically, utilizing a laser speckle flowgraphy device. Results. Postlaser IOP (measured during average 7.7 ± 2.6 months) was 20.2 ± 5.9 mm Hg in EG eyes and 12.3 ± 2.6 mm Hg in control eyes (P < 0.0001). Retinal nerve fiber layer thickness was reduced by 33 ± 22% of the baseline values (P < 0.001) on average in EG eyes and by 0.4 ± 2.3% in control eyes (P > 0.05). The ONH BF remained at a constant level within a range of ocular perfusion pressure (OPP), 41 mm Hg and above. The autoregulation curves, created by all 723 tests in control and 352 tests in EG, were not significantly different (P = 0.71). Conclusions. Optic nerve head BF in normal nonhuman primate (NHP) eyes is effectively regulated within a range of OPP approximately 41 mm Hg and above. Chronic IOP elevation causes no remarkable change to the static autoregulation within the ONH of EG eyes. PMID:24436190

  5. The Effect of Swimming Goggles on Intraocular Pressure and Blood Flow within the Optic Nerve Head

    PubMed Central

    Ma, Kyoung Tak; Chung, Woo Suk; Seo, Kyoung Yul; Seong, Gong Je

    2007-01-01

    Purpose Goggles are frequently worn in the sport of swimming and are designed to form a seal around the periorbital tissue orbit. The resultant pressure on the eye may have the potential to affect intraocular pressure and blood flow of the optic nerve head. This study evaluates the influence of wearing swimming goggles on intraocular pressure (IOP) and blood flow of the ocular nerve head (ONH) in normal subjects. Materials and Methods Thirty healthy participants took part in this study. The IOP of each participant was measured using a Goldmann tonometer. Measurements were taken immediately before putting on swimming goggles, at 5, 10, 30, and 60 minutes after putting on swimming goggles, and then immediately after taking off the goggles. Blood flow of the ONH was measured using the Heidelberg retinal flowmeter. Results The average IOP before, during and after wearing the swimming goggles were 11.88 ± 2.82 mmHg, 14.20 ± 2.81mmHg and 11.78 ± 2.89 mmHg, respectively. The IOP increased immediately after putting on the goggles (p < 0.05) and then returned to normal values immediately after removal (p > 0.05). Blood flow of the ONH was 336.60 ± 89.07 Arbitrary Units (AU) before and 319.18 ± 96.02 AU after the goggles were worn (p < 0.05). Conclusion A small but significant IOP elevation was observed immediately after the swimming goggles were put on. This elevated IOP was maintained while the goggles were kept on, and then returned to normal levels as soon as they were taken off. Blood flow of the ONH did not change significantly throughout the experiment. These facts should be considered for safety concerns, especially in advanced glaucoma patients. PMID:17963338

  6. Regulation of optic nerve head blood flow during combined changes in intraocular pressure and arterial blood pressure

    PubMed Central

    Boltz, Agnes; Schmidl, Doreen; Werkmeister, René M; Lasta, Michael; Kaya, Semira; Palkovits, Stefan; Told, Reinhard; Napora, Katarzyna J; Popa-Cherecheanu, Alina; Garhöfer, Gerhard; Schmetterer, Leopold

    2013-01-01

    In the choroid, there is evidence that blood flow does not only depend on ocular perfusion pressure (OPP), but also on absolute mean arterial pressure (MAP) and intraocular pressure (IOP). The present study included 40 healthy subjects to investigate whether such behavior is also found in the optic nerve head (ONH). The ONH blood flow (ONHBF) was studied using laser Doppler flowmetry during a separate increase in IOP and MAP as well as during a combined elevation. Mean arterial pressure was increased by isometric exercise and IOP by the suction method. During both, the change in ONHBF was less pronounced than the change in OPP indicating autoregulation. Correlation analysis was performed for the combined experiments after pooling all data according to IOP and MAP values. A correlation between ONHBF and MAP was found at IOPs ⩽25 mm Hg (P<0.001), but not at IOPs>25 mm Hg (P=0.79). Optic nerve head blood flow and IOP were significantly correlated (P<0.001), and ONHBF was only slightly dependent on MAP. The data of the present study indicate a complex regulation of ONHBF during combined changes in MAP and IOP. Our results may be compatible with myogenic mechanisms underlying autoregulation, and indicate better ONHBF regulation during an increase in MAP than during an increase in IOP. PMID:23921903

  7. Regulation of optic nerve head blood flow during combined changes in intraocular pressure and arterial blood pressure.

    PubMed

    Boltz, Agnes; Schmidl, Doreen; Werkmeister, René M; Lasta, Michael; Kaya, Semira; Palkovits, Stefan; Told, Reinhard; Napora, Katarzyna J; Popa-Cherecheanu, Alina; Garhöfer, Gerhard; Schmetterer, Leopold

    2013-12-01

    In the choroid, there is evidence that blood flow does not only depend on ocular perfusion pressure (OPP), but also on absolute mean arterial pressure (MAP) and intraocular pressure (IOP). The present study included 40 healthy subjects to investigate whether such behavior is also found in the optic nerve head (ONH). The ONH blood flow (ONHBF) was studied using laser Doppler flowmetry during a separate increase in IOP and MAP as well as during a combined elevation. Mean arterial pressure was increased by isometric exercise and IOP by the suction method. During both, the change in ONHBF was less pronounced than the change in OPP indicating autoregulation. Correlation analysis was performed for the combined experiments after pooling all data according to IOP and MAP values. A correlation between ONHBF and MAP was found at IOPs 25 mm Hg (P<0.001), but not at IOPs>25 mm Hg (P=0.79). Optic nerve head blood flow and IOP were significantly correlated (P<0.001), and ONHBF was only slightly dependent on MAP. The data of the present study indicate a complex regulation of ONHBF during combined changes in MAP and IOP. Our results may be compatible with myogenic mechanisms underlying autoregulation, and indicate better ONHBF regulation during an increase in MAP than during an increase in IOP. PMID:23921903

  8. Laser Doppler measurement of relative blood velocity in the human optic nerve head

    SciTech Connect

    Riva, C.E.; Grunwald, J.E.; Sinclair, S.H.

    1982-02-01

    The Doppler shift frequency spectrum (DSFS) of laser light scattered from red blood cells (RBCs) moving in the microcirculation of the optic nerve head has been recorded in normal volunteers by means of a fundus camera laser Doppler velocimeter. The width of the DSFS, which varies in proportion to the speed of the RBCs, has been characterized by a parameter alpha. With the use of a model for the scattering of light by tissue and RBCs and for the RBC velocity distribution, values of alpha recorded at normal intraocular pressure (IOP) suggest that the RBCs that contribute to the Doppler signal are flowing in capillaries. The parameter alpha was found to vary markedly with the IOP and with the phase of the ocular pressure pulse at elevated IOP. The return of the speed of RBCs toward normal, which is observed after a step increase of IOP above normal and after a step decrease below normal, has been attributed to an autoregulatory response of the optic nerve circulation.

  9. Optic Nerve Head Blood Flow Response to Reduced Ocular Perfusion Pressure by alteration of either the Blood Pressure or Intraocular Pressure

    PubMed Central

    Wang, Lin; Cull, Grant A; Fortune, Brad

    2015-01-01

    Purpose To test the hypothesis that blood flow autoregulation in the optic nerve head has less reserve to maintain normal blood flow in the face of blood pressure-induced ocular perfusion pressure decrease than a similar magnitude intraocular pressure-induced ocular perfusion pressure decrease. Materials and Methods Twelve normal nonhuman primates were anesthetized by continuous intravenous infusion of pentobarbital. Optic nerve blood flow was monitored by laser speckle flowgraphy. In the first group of animals (n=6), the experimental eye intraocular pressure was maintained at 10 mmHg using a saline reservoir connected to the anterior chamber. The blood pressure was gradually reduced by a slow injection of pentobarbital. In the second group (n=6), the intraocular pressure was slowly increased from 10 mmHg to 50 mmHg by raising the reservoir. In both experimental groups, optic nerve head blood flow was measured continuously. The blood pressure and intraocular pressure were simultaneously recorded in all experiments. Results The optic nerve head blood flow showed significant difference between the two groups (P = 0.021, repeat measures analysis of variance). It declined significantly more in the blood pressure group compared to the intraocular pressure group when the ocular perfusion pressure was reduced to 35 mmHg (P<0.045) and below. There was also a significant interaction between blood flow changes and the ocular perfusion pressure treatment (P=0.004, adjusted Greenhouse & Geisser univariate test), indicating the gradually enlarged blood flow difference between the two groups was due to the ocular perfusion pressure decrease. Conclusions The results show that optic nerve head blood flow is more susceptible to an ocular perfusion pressure decrease induced by lowering the blood pressure compared with that induced by increasing the intraocular pressure. This blood flow autoregulation capacity vulnerability to low blood pressure may provide experimental evidence

  10. Diurnal Variations in Blood Flow at Optic Nerve Head and Choroid in Healthy Eyes

    PubMed Central

    Iwase, Takeshi; Yamamoto, Kentaro; Ra, Eimei; Murotani, Kenta; Matsui, Shigeyuki; Terasaki, Hiroko

    2015-01-01

    Abstract To investigate the diurnal variations of the ocular blood flow in healthy eyes using laser speckle flowgraphy (LSFG), and to determine the relationship of the diurnal variations between the ocular blood flow and other ocular parameters. This prospective cross-sectional study was conducted at Nagoya University Hospital. We studied 13 healthy volunteers whose mean age was 33.5 ± 7.6 years. The mean blur rate (MBR), expressing the relative blood flow, on the optic nerve head (ONH) and choroidal blood flow was determined by LSFG (LSFG-NAVI) every 3 hours from 6:00 to 24:00 hours. The intraocular pressure (IOP), choroidal thickness measured by enhanced depth imaging optical coherence tomography, systolic (SBP) and diastolic (DBP) blood pressure, and heart rate (HR) in the brachial artery were also recorded. We evaluated the diurnal variations of the parameters and compared the MBR to the other parameters using a linear mixed model. The diurnal variations of the MBR on the ONH varied significantly with a trough at 9:00 hours and a peak at 24:00 hours (P < 0.001, linear mixed model). The MBR of choroid also had significant diurnal variations with a trough at 15:00 hours and a peak at 18:00 hours (P = 0.001). The IOP (P < 0.001), choroidal thickness (P < 0.001), SBP (P = 0.005), DBP (P = 0.001), and HR (P < 0.001) also had significant diurnal variations. Although the diurnal variation of the MBR on the ONH was different from the other parameters, that on the choroid was significantly and positively correlated with the DBP (P = 0.002), mean arterial pressure (P = 0.023), and mean ocular perfusion pressure (P = 0.047). We found significant diurnal variations in the ONH and choroidal blood flow. Although the ONH blood flow had its own diurnal variation because of strong autoregulation, the choroidal blood flow was more likely affected by systemic circulatory factors because of poor autoregulation. PMID:25674750

  11. Longitudinal Alterations in the Dynamic Autoregulation of Optic Nerve Head Blood Flow Revealed in Experimental Glaucoma

    PubMed Central

    Wang, Lin; Cull, Grant; Burgoyne, Claude F.; Thompson, Simon; Fortune, Brad

    2014-01-01

    Purpose. To use a novel dynamic autoregulation analysis (dAR) to test the hypothesis that the optic nerve head (ONH) blood flow (BF) autoregulation is disrupted during early stages of experimental glaucoma (EG) in nonhuman primates. Methods. Retinal nerve fiber layer thickness (RNFLT, assessed by optical coherence tomography) and ONH BF (assessed by laser speckle imaging technique) were measured biweekly before and after unilateral laser treatment to the trabecular meshwork. Each nonhuman primate was followed until reaching either an early stage of damage (RNFLT loss < 20%, n = 6) or moderate to advanced stages of damage (RNFLT loss > 20%, n = 9). At each test, dAR was assessed by characterizing ONH BF changes during the first minute of rapid manometrical intraocular pressure (IOP) elevation from 10 to 40 mm Hg. The dAR analysis extracted the following parameters: baseline BF, average BF 10 seconds before IOP elevation; BFΔmax, maximum BF change from baseline BF; Tr, time from baseline BF to the BFΔmax; Kr, average descending BF rate. Results. Mean postlaser IOP was 20.2 ± 5.9 and 12.3 ± 2.6 mm Hg in EG and control eyes, respectively (P < 0.0001). Compared with prelaser values, baseline BF was higher in early EG, but lower in moderate to advanced EG (P = 0.01). Tr was increased and Kr was reduced in both stages (P < 0.01). BFΔmax was smaller in the early EG (P = 0.05) and remained low in the moderate to advanced EG (P = 0.15). No changes in the parameters were observed in control eyes. Conclusions. Chronic IOP elevation causes ONH autoregulation dysfunction in the early stage of EG, characterized by a disrupted BF response and delayed Tr, revealed by dAR analysis. PMID:24812551

  12. Parametric transfer function analysis and modeling of blood flow autoregulation in the optic nerve head

    PubMed Central

    Yu, Jintao; Liang, Yi; Thompson, Simon; Cull, Grant; Wang, Lin

    2014-01-01

    The aim of the study was to establish a parametric transfer function to describe the relationship between ocular perfusion pressure (OPP) and blood flow (BF) in the optic nerve head (ONH). A third-order parametric theoretical model was proposed to describe the ONH OPP-BF relationship within the lower OPP range of the autoregulation curve (< 80 mmHg) based on experimentally induced BF response to a rapid intraocular pressure (IOP) increase in 6 rhesus monkeys. The theoretical and actual data fitted well and suggest that this parametric third-order transfer function can effectively describe both the linear and nonlinear feature in dynamic and static autoregulation in the ONH within the OPP range studied. It shows that the BF autoregulation fully functions when the OPP was > 40 mmHg and becomes incomplete when the OPP was < 40 mmHg. This model may be used to help investigating the features of autoregulation in the ONH under different experimental conditions. PMID:24665355

  13. Quantification of dynamic blood flow autoregulation in optic nerve head of rhesus monkeys.

    PubMed

    Liang, Yi; Fortune, Brad; Cull, Grant; Cioffi, George A; Wang, Lin

    2010-02-01

    Autoregulation capacity has been classically assessed with a 'two-point' measurement or static autoregulation (sAR). In such an approach, stabilized hemodynamic parameters are determined before and after a perfusion pressure challenge. Analysis of dynamic autoregulation (dAR), an early phase of blood flow response to a sudden perfusion pressure change is emerging as a preferred approach to assess the capacity of autoregulation in many non-ocular tissues and has developed rapidly in the last decade. The purpose of this study was to develop a method to quantify dAR in the optic nerve head (ONH). In six pentobarbital (6-9 mg/kg/h, IV) anesthetized rhesus monkeys, dAR was elicited by increasing intraocular pressure (IOP) from 10 to 30 or 40 mmHg (IOP(10-30)/IOP(10-40)) manometrically via switch between reservoirs connected to the anterior chamber. Relative blood flow changes during dAR in the ONH, estimated with a laser speckle flowgraph (LSFG), were continuously measured for 1 min. Time-domain parameters of dAR response, including: BF(Deltamax) (maximal blood flow decrease, %), K(r) (descending slope of blood flow from baseline to BF(Deltamax)) and T(r) (descending time of blood flow from baseline to BF(Deltamax)) were extracted and analyzed offline. For each monkey, same procedure was repeated three times during three different visits. The test-retest repeatability and inter-ocular difference of the parameters was statistically evaluated. During IOP(10-30) and IOP(10-40), the mean arterial BP was 89 +/- 7 and 85 +/- 6 mmHg, respectively. Immediately after the reservoir was switched, the blood flow started to decline and reached maximal in approximately 4 s. The blood flow then returned back toward baseline despite continuous IOP increase, which took 8-11 s to reach the level of the raised reservoir. The general pattern of blood flow responses was similar between IOP(10-30) and IOP(10-40) and there was no statistically significant difference for T(r) (P > 0

  14. Diurnal variations in blood flow at optic nerve head and choroid in healthy eyes: diurnal variations in blood flow.

    PubMed

    Iwase, Takeshi; Yamamoto, Kentaro; Ra, Eimei; Murotani, Kenta; Matsui, Shigeyuki; Terasaki, Hiroko

    2015-02-01

    To investigate the diurnal variations of the ocular blood flow in healthy eyes using laser speckle flowgraphy (LSFG), and to determine the relationship of the diurnal variations between the ocular blood flow and other ocular parameters.This prospective cross-sectional study was conducted at Nagoya University Hospital. We studied 13 healthy volunteers whose mean age was 33.5 ± 7.6 years. The mean blur rate (MBR), expressing the relative blood flow, on the optic nerve head (ONH) and choroidal blood flow was determined by LSFG (LSFG-NAVI) every 3 hours from 6:00 to 24:00 hours. The intraocular pressure (IOP), choroidal thickness measured by enhanced depth imaging optical coherence tomography, systolic (SBP) and diastolic (DBP) blood pressure, and heart rate (HR) in the brachial artery were also recorded. We evaluated the diurnal variations of the parameters and compared the MBR to the other parameters using a linear mixed model.The diurnal variations of the MBR on the ONH varied significantly with a trough at 9:00 hours and a peak at 24:00 hours (P < 0.001, linear mixed model). The MBR of choroid also had significant diurnal variations with a trough at 15:00 hours and a peak at 18:00 hours (P = 0.001). The IOP (P < 0.001), choroidal thickness (P < 0.001), SBP (P = 0.005), DBP (P = 0.001), and HR (P < 0.001) also had significant diurnal variations. Although the diurnal variation of the MBR on the ONH was different from the other parameters, that on the choroid was significantly and positively correlated with the DBP (P = 0.002), mean arterial pressure (P = 0.023), and mean ocular perfusion pressure (P = 0.047).We found significant diurnal variations in the ONH and choroidal blood flow. Although the ONH blood flow had its own diurnal variation because of strong autoregulation, the choroidal blood flow was more likely affected by systemic circulatory factors because of poor autoregulation. PMID:25674750

  15. Blood flow measurements within optic nerve head during on-pump cardiovascular operations. A window to the brain?

    PubMed

    Nenekidis, Ioannis; Geiser, Martial; Riva, Charles; Pournaras, Constantin; Tsironi, Evangelia; Vretzakis, Georgios; Mitilis, Vasilios; Tsilimingas, Nikolaos

    2011-05-01

    This observational study is conducted to demonstrate optic nerve head (ONH) blood flow alterations during extracorporeal circulation (ECC) in routine on-pump cardiovascular operations in order to evaluate the perfusion status of important autoregulatory tissue vascular beds during moderate hypothermia. Twenty-one patients free from eye disease were prospectively enrolled in our database. Perioperative ONH blood flow measurements were performed using a hand-held portable ocular laser Doppler flowmeter just after administration of general anesthesia and during cardiopulmonary bypass (CPB) upon the lowest temperature point of moderate hypothermia. Important operative flow variables were correlated to optic nerve blood flow during surgical phases. Statistical analysis showed significant reduction of 32.1 ± 14.5% of mean ONH blood flow in phase 2 (P < 0.0001) compared to the reference flow values of phase 1. A negative univariate association between ECC time and ONH blood flow in phase 2 (P = 0.031) is noted. This angiokinetic approach can detect changes of flow within autoregulatory vascular tissue beds like ONH, thus creating a 'window' on cerebral microvasculature. ONH blood flow is reduced during CPB. Our data suggest that it is of paramount importance to avoid extracorporeal prolongation even in moderate hypothermic cardiovascular operations. PMID:21297131

  16. 3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head

    NASA Astrophysics Data System (ADS)

    Lee, Kyungmoo; Abràmoff, Michael D.; Niemeijer, Meindert; Garvin, Mona K.; Sonka, Milan

    2010-03-01

    Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from spectral-domain OCT scans centered on the optic nerve head (ONH). The proposed method utilized a fast multiscale 3-D graph search to segment retinal surfaces as well as a triangular mesh-based 3-D graph search to detect retinal blood vessels. An experiment on 30 ONH-centered OCT scans (15 right eye scans and 15 left eye scans) from 15 subjects was performed, and the mean unsigned error in 3-D of the computer segmentations compared with the independent standard obtained from a retinal specialist was 3.4 +/- 2.5 voxels (0.10 +/- 0.07 mm).

  17. Role of nitric oxide in optic nerve head blood flow regulation during an experimental increase in intraocular pressure in healthy humans.

    PubMed

    Schmidl, Doreen; Boltz, Agnes; Kaya, Semira; Palkovits, Stefan; Told, Reinhard; Napora, Katarzyna Jadwiga; Cherecheanu, Alina Popa; Werkmeister, René Marcel; Garhofer, Gerhard; Schmetterer, Leopold

    2013-11-01

    The present study set out to investigate whether nitric oxide, a potent vasodilator, is involved in the regulatory processes in optic nerve head blood flow during an experimental increase in intraocular pressure (IOP). The study was conducted in a randomized, double-masked, placebo-controlled, three way cross-over design. 12 healthy subjects were scheduled to receive either L-NMMA (an unspecific nitric oxide synthase inhibitor), phenylephrine (an α-adrenoceptor agonist) or placebo on three different study days. Optic nerve head blood flow was measured using laser Doppler flowmetry and IOP was increased stepwise with a suction cup. Mean arterial pressure (MAP) and IOP were measured non-invasively and ocular perfusion pressure (OPP) was calculated as OPP = 2/3 MAP-IOP. Administration of L-NMMA and phenylephrine significantly increased MAP and therefore OPP at rest (p < 0.01). L-NMMA significantly reduced baseline blood flow in the optic nerve head (p < 0.01). Application of the suction cup induced a significant increase in IOP and a decrease in OPP (p < 0.01). During the stepwise increase in IOP, some autoregulatory potential was observed until OPP decreased approximately -30% below baseline. None of the administered substances had an effect on this autoregulatory behavior (p = 0.49). The results of the present study confirm that the human optic nerve head shows some regulatory capacity during a decrease in OPP. Nitric oxide is involved in the regulation of basal vascular tone in the optic nerve head but does not seem to be involved in the regulatory mechanisms during an acute increase in IOP in young healthy subjects. PMID:24060346

  18. [Blood flow changes in the optic nerve head of albino rabbits following intravenous administration of brovincamine fumarate, an improver of cerebral circulation and metabolism].

    PubMed

    Nirei, M

    1996-02-01

    The blood flow changes in the optic nerve head in adult albino rabbits following intravenous administration of brovincamine fumarate, an improver of cerebral circulation and metabolism, were investigated employing the hydrogen clearance method. In the brovincamine fumarate (0.1 mg/kg)-administered group, the blood flow in the optic nerve head increased soon after injection and reached the maximal value of 124.2 +/- 7.3% against the value before injection, at 20 minutes after injection, followed by a gradual decrease in the blood flow. Statistical analysis showed a significant increase (p < 0.05) in the blood flow at 10 to 40 minutes after injection, compared with the value before injection in the brovincamine fumarate (0.1 mg/kg)-administered group, but no significant increases in the blood flow were observed in either the brovincamine fumarate (0.5 mg/kg)-administered group or the control group given no brovincamine fumarate throughout the course. No significant changes in the mean values of the blood pressure in the femoral artery, pulse rate, respiratory rate or rectal temperature were observed in any group through the experiment. To learn the mechanism of the different efficacy of the two doses, further studies are needed in light of the cyclic adenosine monophosphate (cyclic AMP) changes induced by brovincamine fumarate administration or in light of the receptor responsiveness to the drug concentration. PMID:8851150

  19. Hyperemic responses of the optic nerve head blood flow to chromatic equiluminant flicker are reduced by ocular hypertension and early glaucoma

    NASA Astrophysics Data System (ADS)

    Falsini, Benedetto; Riva, Charles E.; Salgarello, Tommaso; Logean, Eric; Colotto, Alberto; Giudiceandrea, Andrea

    2014-06-01

    We evaluated in ocular hypertension (OHT) and early glaucoma (EOAG) patients the optic nerve head (ONH) blood flow response (RF) to chromatic equiluminant flicker. This stimulus generates neural activity dominated by the parvo-cellular system. Eleven EOAG, 20 OHT patients, and 8 age-matched control subjects were examined. The blood flow (F) at the neuroretinal rim was continuously monitored by laser Doppler flowmetry before, during, and after a 60-s exposure to a 4 Hz, red-green equiluminant flicker stimulus (30 deg field). RF was expressed as percentage F-change during the last 20 s of flicker relative to baseline F. Responses were collected at a number of temporal sites. The highest RF value was used for subsequent analysis. As compared to controls, both OHT and EOAG patients showed a decrease (p<0.01) in mean RF. We conclude that RF elicited by chromatic equiluminant flicker is abnormally reduced in OHT and EOAG patients indicating an impairment of the parvo-cellular-mediated vasoactivity. This decrease of vascular response may occur independently of neural activity loss early in the disease process.

  20. Anterior and Posterior Optic Nerve Head Blood Flow in Nonhuman Primate Experimental Glaucoma Model Measured by Laser Speckle Imaging Technique and Microsphere Method

    PubMed Central

    Wang, Lin; Cull, Grant A.; Piper, Chelsea; Burgoyne, Claude F.; Fortune, Brad

    2012-01-01

    Purpose. To characterize optic nerve head (ONH) blood flow (BF) changes in nonhuman primate experimental glaucoma (EG) using laser speckle flowgraphy (LSFG) and the microsphere method and to evaluate the correlation between the two methods. Methods. EG was induced in one eye each of 9 rhesus macaques by laser treatment to the trabecular meshwork. Prior to lasering and following onset of intraocular pressure (IOP) elevation, retinal never fiber layer thickness (RNFLT) and ONH BF were measured biweekly by spectral-domain optical coherence tomography and LSFG, respectively, until RNFLT loss was approximately 40% in the EG eye. Final BF was measured by LSFG and by the microsphere method in the anterior ONH (MS-BFANT), posterior ONH (MS-BFPOST), and peripapillary retina (MS-BFPP). Results. Baseline RNFLT and LSFG-BF showed no difference between the two eyes (P = 0.69 and P = 0.43, respectively, paired t-test). Mean (±SD) IOP was 30 ± 6 mm Hg in EG eyes and 13 ± 2 mm Hg in control eyes (P < 0.001). EG eye RNFLT and LSFG-BF were reduced by 42 ± 16% (P < 0.0001) and 22 ± 13% (P = 0.003), respectively, at the final time point. EG eye MS-BFANT, MS-BFPOST, and MS-BFPP were reduced by 41 ± 17% (P < 0.001), 22 ± 34% (P = 0.06), and 30 ± 12% (P = 0.001), respectively, compared with the control eyes. Interocular ONH LSFG-BF differences significantly correlated to that measured by the microsphere method (R2 = 0.87, P < 0.001). Conclusions. Chronic IOP elevation causes significant ONH BF decreases in the EG model. The high correlation between the BF reduction measured by LSFG and the microsphere method provides evidence that the LSFG is capable of assaying BF for a critical deep ONH region. PMID:23169886

  1. Automated optic-nerve-head analysis using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Kulkarni, Manish D.; Harman, Jonathan W.; Kim, Robert; Kirschbaum, Alan R.; Pedersen, Per; Everett, Matthew J.; Wei, Jay

    2002-06-01

    The early identification of glaucomatous development is extremely important for treatment of glaucoma. Analysis of optic-nerve-head features may play a crucial role for early glaucoma diagnostics. Here we propose a critical parameter, viz., nerve tissue area, which may prove to be extremely useful for detection of glaucoma in early stages. We report a novel and robust algorithm for OCT-based automatic, objective extraction of critical optic-nerve-head features such as optic disc, nerve tissue area, and optic cup for the first time.

  2. What is a typical optic nerve head?

    PubMed

    Voorhees, A P; Grimm, J L; Bilonick, R A; Kagemann, L; Ishikawa, H; Schuman, J S; Wollstein, G; Sigal, I A

    2016-08-01

    Whereas it is known that elevated intraocular pressure (IOP) increases the risk of glaucoma, it is not known why optic nerve heads (ONHs) vary so much in sensitivity to IOP and how this sensitivity depends on the characteristics of the ONH such as tissue mechanical properties and geometry. It is often assumed that ONHs with uncommon or atypical sensitivity to IOP, high sensitivity in normal tension glaucoma or high robustness in ocular hypertension, also have atypical ONH characteristics. Here we address two specific questions quantitatively: Do atypical ONH characteristics necessarily lead to atypical biomechanical responses to elevated IOP? And, do typical biomechanical responses necessarily come from ONHs with typical characteristics. We generated 100,000 ONH numerical models with randomly selected values for the characteristics, all falling within literature ranges of normal ONHs. The models were solved to predict their biomechanical response to an increase in IOP. We classified ONH characteristics and biomechanical responses into typical or atypical using a percentile-based threshold, and calculated the fraction of ONHs for which the answers to the two questions were true and/or false. We then studied the effects of varying the percentile threshold. We found that when we classified the extreme 5% of individual ONH characteristics or responses as atypical, only 28% of ONHs with an atypical characteristic had an atypical response. Further, almost 29% of typical responses came from ONHs with at least one atypical characteristic. Thus, the answer to both questions is no. This answer held irrespective of the threshold for classifying typical or atypical. Our results challenge the assumption that ONHs with atypical sensitivity to IOP must have atypical characteristics. This finding suggests that the traditional approach of identifying risk factors by comparing characteristics between patient groups (e.g. ocular hypertensive vs. primary open angle glaucoma) may not

  3. Astrocytes in the optic nerve head express putative mechanosensitive channels

    PubMed Central

    Choi, Hee Joo; Sun, Daniel

    2015-01-01

    Purpose To establish whether optic nerve head astrocytes express candidate molecules to sense tissue stretch. Methods We used conventional PCR, quantitative PCR, and single-cell reverse transcription PCR (RT–PCR) to assess the expression of various members of the transient receptor potential (TRP) channel family and of the recently characterized mechanosensitive channels Piezo1 and 2 in optic nerve head tissue and in single, isolated astrocytes. Results Most TRP subfamilies (TRPC, TRPM, TRPV, TRPA, and TRPP) and Piezo1 and 2 were expressed in the optic nerve head of the mouse. Quantitative real-time PCR analysis showed that TRPC1, TRPM7, TRPV2, TRPP2, and Piezo1 are the dominant isoforms in each subfamily. Single-cell RT–PCR revealed that many TRP isoforms, TRPC1–2, TRPC6, TRPV2, TRPV4, TRPM2, TRPM4, TRPM6–7, TRPP1–2, and Piezo1–2, are expressed in astrocytes of the optic nerve head, and that most astrocytes express TRPC1 and TRPP1–2. Comparisons of the TRPP and Piezo expression levels between different tissue regions showed that Piezo2 expression was higher in the optic nerve head and the optic nerve proper than in the brain and the corpus callosum. TRPP2 also showed higher expression in the optic nerve head. Conclusions Astrocytes in the optic nerve head express multiple putative mechanosensitive channels, in particular the recently identified channels Piezo1 and 2. The expression of putative mechanosensitive channels in these cells may contribute to their responsiveness to traumatic or glaucomatous injury. PMID:26236150

  4. Humeral head translation after a suprascapular nerve block.

    PubMed

    San Juan, Jun G; Kosek, Peter; Karduna, Andrew R

    2013-08-01

    Subacromial impingement syndrome is the most common shoulder disorder. Abnormal superior translation of the humeral head is believed to be a major cause of this pathology. The first purpose of the study was to examine the effects of suprascapular nerve block on superior translation of the humeral head and scapular upward rotation during dynamic shoulder elevation. The secondary purpose was to assess muscle activation patterns during these motions. Twenty healthy subjects participated in the study. Using fluoroscopy and electromyography, humeral head translation and muscle activation were measured before and after a suprascapular nerve block. The humeral head was superiorly located at 60 degrees of humeral elevation, and the scapula was more upwardly rotated from 30 to 90 degrees of humeral elevation after the block. The differences were observed during midrange of motion. In addition, the deltoid muscle group demonstrated increased muscle activation after the nerve block. The study's results showed a compensatory increase in humeral head translation, scapular upward rotation, and deltoid muscle activation due to the nerve block. These outcomes suggest that increasing muscular strength and endurance of the supraspinatus and infraspinatus muscles could prevent any increased superior humeral head translation. This may be beneficial in reducing shoulder impingement or rotator cuff tears over time. PMID:22927503

  5. Isolated unilateral oculomotor nerve palsy due to head trauma

    PubMed Central

    Erenler, Ali Kemal; Yalçın, Anıl; Baydin, Ahmet

    2015-01-01

    Unilateral oculomotor nerve palsy is a rare and challenging condition for both emergency department (ED) physicians and neurosurgeons. In this report, we present you a case of head trauma with oculomotor nerve palsy whose initial neuroimaging findings were normal. A 50-year-old female presented to our ED due to head trauma secondary to fall from height. On her physical examination, ptosis, minimal lateral deviation, and dilated pupilla unresponsive to the light were determined in the left eye. A computed tomography and magnetic resonance imaging were performed and both were found to be normal. Patient was consulted with an ophthalmologist and any sign of direct trauma to the eye was not determined. Then, the patient was consulted with a neurosurgeon and hospitalized. In some rare instances, minor traumas to the head may result in isolated oculomotor nerve palsy without accompanying findings. Neurosurgeons and ED physicians must be careful about this rare condition. PMID:26396626

  6. Contour Photography Of The Optic Nerve Head: Stereometric Basis

    NASA Astrophysics Data System (ADS)

    Shapiro, Jerrold M.

    1983-07-01

    Three dimensional analysis of the optic nerve head is important in the detection and treatment of eye diseases, particularly glaucoma. In glaucoma, the fluid pressure within the eye increases. Since there is a wide variability in people's sensitivity to elevated pressure, it is not possible to predict which eye will be damaged by a given pressure. The side effects of treatment preclude treating everyone with elevated pressure. However, those eyes susceptible to elevated pressure slowly begin to show erosion of the optic nerve head. The erosion process progresses very slowly and imperceptibly. By the time it can be detected visually, permanent visual loss has often occurred.

  7. [Blood-nerve barrier: structure and function].

    PubMed

    Kanda, Takashi

    2011-06-01

    The blood-nerve barrier (BNB) is a dynamic interface between the endoneurial microenvironment and surrounding extracellular space or blood contents, and is localized the innermost layer of multilayered ensheathing perineurium and endoneurial microvessels. Since the BNB is a key structure controlling the internal milieu of the peripheral nerve parenchyma, adequate understanding of the BNB is crucial for developing treatment strategies for human peripheral nervous system disorders, including Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, and diabetic and various metabolic/toxic neuropathies. However, fewer studies have been conducted on the BNB, if we compare against the number of studies on the blood-brain barrier. This is because of the lack of adequate human cell lines originating from the BNB. In our laboratory, human immortal cell lines from the BNB, namely, the endothelial cell line and pericyte cell line, have recently been established and vigorous investigations of their biological and physiological properties are now underway. Pericytes constituting the BNB were found to possess robust ability of controlling BNB integrity via secretion of various cytokines and growth factors including bFGF, VEGF, GDNF, BDNF, and angiopoietin-1. Unknown soluble factors secreted by pericytes also contribute to the upregulation of claudin-5 in endothelial cells in the BNB and thus, strengthen the barrier function of the BNB. In diabetic neuropathy, pericytes were shown to regulate the vascular basement membrane, while AGEs were shown to induce basement membrane hypertrophy and disrupt the BNB by increasing the autocrine secretion of VEGF and TGF-beta from pericytes. In this review article, we discuss the macroscopic and microscopic anatomy of the human BNB as well as the molecular mechanisms of mononuclear cell infiltration across the BNB. PMID:21613659

  8. Oxygen saturation changes in the optic nerve head during acute intraocular pressure elevation in monkeys

    NASA Astrophysics Data System (ADS)

    Khoobehi, Bahram; Kawano, Hiroyuki; Ning, Jinfeng; Burgoyne, Claude F.; Rice, David A.; Khan, Fareeha; Thompson, Hilary W.; Beach, James M.

    2009-02-01

    Background and Objective: To evaluate the effect of an acute elevated intraocular pressure (IOP) on oxygen saturation of structures of the optic nerve head. Study Design/Materials and Methods: In the cynomolgus monkey eye, IOP was set to 10 mm Hg, and then raised to 30, 45, and 55 mm Hg. The ONH and overlying vessels were imaged using a fundus camera attached to a hyperspectral imaging system (HSI) at 10 and 30 minutes after IOP elevation. Results: Raising IOP from 10 to 30 mm Hg did not significantly (P < 0.0001) change saturation in vessels or ONH tissue structures but at 55 mm Hg, all structures showed significant reduction. Conclusions: Quantitative assay of the blood oxygen saturation in structures on the surface and overlying the optic nerve head is possible using hyperspectral imaging techniques.

  9. Morphometry of the myopic optic nerve head using FDOCT

    NASA Astrophysics Data System (ADS)

    Lee, Sieun; Young, Mei; Lebed, Evgeniy; Mackenzie, Paul J.; Beg, Mirza F.; Sarunic, Marinko V.

    2011-03-01

    In this paper we present imaging and morphometric analysis of a myopic Optic Nerve Head (ONH) using an 830nm wavelength Fourier domain optical coherence tomography system. The thinner prelaminar neural tissue and shallower optic cup in the myopic subject allows visualization of the tissue structures such as anterior laminar surface and lamina cribrosa that are often challenging to image due to their depth. From these structures we measured volumetric anatomical parameters and topographical tissue thickness correlated with glaucomatous structural damage in the ONH.

  10. Angiogram, fundus, and oxygen saturation optic nerve head image fusion

    NASA Astrophysics Data System (ADS)

    Cao, Hua; Khoobehi, Bahram

    2009-02-01

    A novel multi-modality optic nerve head image fusion approach has been successfully designed. The new approach has been applied on three ophthalmologic modalities: angiogram, fundus, and oxygen saturation retinal optic nerve head images. It has achieved an excellent result by giving the visualization of fundus or oxygen saturation images with a complete angiogram overlay. During this study, two contributions have been made in terms of novelty, efficiency, and accuracy. The first contribution is the automated control point detection algorithm for multi-sensor images. The new method employs retina vasculature and bifurcation features by identifying the initial good-guess of control points using the Adaptive Exploratory Algorithm. The second contribution is the heuristic optimization fusion algorithm. In order to maximize the objective function (Mutual-Pixel-Count), the iteration algorithm adjusts the initial guess of the control points at the sub-pixel level. A refinement of the parameter set is obtained at the end of each loop, and finally an optimal fused image is generated at the end of the iteration. It is the first time that Mutual-Pixel-Count concept has been introduced into biomedical image fusion area. By locking the images in one place, the fused image allows ophthalmologists to match the same eye over time and get a sense of disease progress and pinpoint surgical tools. The new algorithm can be easily expanded to human or animals' 3D eye, brain, or body image registration and fusion.

  11. Optical coherence tomography imaging of the optic nerve head pre optic and post optic nerve sheath fenestration.

    PubMed

    Chowdhury, Haziq Raees; Rajak, Saul; Heath, Dominic; Brittain, Paul

    2015-01-01

    Idiopathic intracranial hypertension (IIH) is a disorder of unknown aetiology, and causes elevated intracranial pressures. This is often associated with papilloedema with subsequent degrees of optic atrophy if the intracranial pressures are not controlled in a timely manner. Optical coherence tomography imaging is widely recognised for its use in the monitoring of optic nerves in glaucoma, and this report is the first to describe its use to monitor the optic nerve head pre optic and post optic nerve sheath fenestration. PMID:26150609

  12. Changes in the blood-nerve barrier after sciatic nerve cold injury: indications supporting early treatment

    PubMed Central

    Li, Hao; Jia, Jian-ping; Xu, Min; Zhang, Lei

    2015-01-01

    Severe edema in the endoneurium can occur after non-freezing cold injury to the peripheral nerve, which suggests damage to the blood-nerve barrier. To determine the effects of cold injury on the blood-nerve barrier, the sciatic nerve on one side of Wistar rats was treated with low temperatures (3–5°C) for 2 hours. The contralateral sciatic nerve was used as a control. We assessed changes in the nerves using Evans blue as a fluid tracer and morphological methods. Excess fluid was found in the endoneurium 1 day after cold injury, though the tight junctions between cells remained closed. From 3 to 5 days after the cold injury, the fluid was still present, but the tight junctions were open. Less tracer leakage was found from 3 to 5 days after the cold injury compared with 1 day after injury. The cold injury resulted in a breakdown of the blood-nerve barrier function, which caused endoneurial edema. However, during the early period, the breakdown of the blood-nerve barrier did not include the opening of tight junctions, but was due to other factors. Excessive fluid volume produced a large increase in the endoneurial fluid pressure, prevented liquid penetration into the endoneurium from the microvasculature. These results suggest that drug treatment to patients with cold injuries should be administered during the early period after injury because it may be more difficult for the drug to reach the injury site through the microcirculation after the tissue fluid pressure becomes elevated. PMID:25878590

  13. Reproducibility of topographic measures of the glaucomatous optic nerve head

    PubMed Central

    Geyer, O; Michaeli-Cohen, A; Silver, D; Versano, D; Neudorfer, M; Dzhanov, R; Lazar, M

    1998-01-01

    AIMS/BACKGROUND—Laser scanning tomography provides an assessment of three dimensional optic disc topography. For the clinical purpose of follow up of glaucoma patients, the repeatability of the various measured variables is essential. In the present study, the reproducibility of morphometric variables calculated by the topographic scanning system, TopSS (Laser Diagnostic Technology, San Diego, CA) was investigated.
METHODS—Two independent measurements (30 minutes apart) each consisting of three complete images of the optic disc were performed on 16 eyes of 16 glaucoma patients using a TopSS. The instrument calculates 14 morphometric variables for the characterisation of the optic disc.
RESULTS—From the two tailed paired tests, all variables were seen to have good reproducibility. However, correlation and regression analyses showed that only the three variables, volume below, half depth area, and average cup depth, are acceptably reproducible.
CONCLUSION—The TopSS provides three variables which describe the physiological shape of the optic disc that have high reproducibility. These three variables might be useful for following the progression of optic disc changes in glaucoma patients.

 Keywords: optic nerve head; scanning laser; glaucoma; tomography PMID:9536873

  14. [Blood vessel and nerve damage in total hip arthroplasty].

    PubMed

    Dietze, S; Perka, C; Baecker, H

    2014-01-01

    Blood vessel and nerve damage are uncommon complications in total hip arthroplasty (THA). With an incidence between 0.1 and 0.2 % in primary THA these complications are rare but can be serious with a high mortality risk. The individual risk is determined by multiple factors depending on the surgeon's skills, the number of previous surgeries and the approach itself. The anatomy of the defect is an essential risk factor. Some procedures, such as the use of screws for cup fixation are associated with a higher risk of vascular and neural damage. The acetabular quadrant system of the hip as described by Wasielewski et al. is a useful tool to visualize the neurovascular anatomy of the hip, to detect the safe zone and subsequently prevent complications. Sciatic nerve palsy after total hip replacement is the most common nerve damage followed by femoral nerve damage. Previous surgery, a posterior approach and excessive leg extension are the most common risk factors for nerve damage. In order to diagnose nerve palsy after orthopedic surgery an electromyogram can be of use to assess the extent and prognosis. This article focuses on vascular and neural complications after total hip arthroplasty and the options for diagnosis, treatment and prevention. PMID:24384891

  15. Compromised Optic Nerve Blood Flow and Autoregulation Secondary to Neural Degeneration

    PubMed Central

    Cull, Grant; Told, Reinhard; Burgoyne, Claude F.; Thompson, Simon; Fortune, Brad; Wang, Lin

    2015-01-01

    Purpose To test the hypothesis that optic nerve head (ONH) blood flow (BF) and autoregulation compromise are consequences of optic nerve degeneration induced by surgical optic nerve transection (ONT). Methods In both eyes of five nonhuman primates, peripapillary retinal nerve fiber layer thickness (RNFLT) was measured by spectral-domain optical coherence tomography. Optic nerve head BF and dynamic autoregulation responses to a rapid manometric IOP increase (from 10–40 mm Hg) were measured by Laser Speckle Flowgraphy. The measurements were conducted every 10 to 15 days before and after unilateral ONT. Post-ONT measurements were repeated until RNFLT in the ONT eye was reduced by more than 40% of baseline value. Results After ONT, RNFLT, and ONH BF progressively declined over time (P < 0.0001 and P = 0.02, respectively). Longitudinal changes between the two were highly correlated (P < 0.0001). When data was grouped by test session, the first significant decreases for RNFLT and BF were found 13 ± 0.8 and 24 ± 3.2 days post ONT, respectively (P < 0.05, both). At the final time point (55 ± 0.5 days post ONT), RNFLT, and BF were reduced by 44% ± 2.0% and 38 ± 5.0% from baseline, respectively. Dynamic autoregulation analysis showed marginal increased response time in post-ONT eyes (P = 0.05). Control eyes showed no longitudinal changes for any parameter. Conclusions The close association between RNFLT loss and ONH BF decrease following optic nerve degeneration demonstrated a clear cause and effect relationship. Increased BF response time appears to be a sign of dynamic autoregulation dysfunction in this ONT model. PMID:26551332

  16. Modulation of Factors Affecting Optic Nerve Head Astrocyte Migration

    PubMed Central

    Miao, Haixi; Crabb, Andrea W.; Hernandez, M. Rosario

    2010-01-01

    Purpose. The authors investigated the role of myosin light chain kinase (MYLK) and transforming growth factor beta (TGFβ) receptor pathways in optic nerve head (ONH) astrocyte migration. They further investigated how the expression of these genes is altered by elevated hydrostatic pressure (HP). Methods. PCR was used to determine the isoforms of MYLK expressed in ONH astrocytes. siRNAs against MYLK (all isoforms) and TGFβ receptor 2 (TGFBR2) were prepared and tested for effects on the migration of cultured ONH astrocytes. Finally, the effects of elevated HP (24–96 hours) on the expression of MYLK isoforms and selected TGFβ pathway components were measured. Results. Multiple isoforms of MYLK are present in ONH astrocytes from Caucasian (CA) and African American (AA) donors. Both populations express the short form (MYLK-130) and the long form (MYLK-210) of MYLK and a splicing variant within MYLK-210. MYLK-directed siRNA decreased MYLK expression and cell migration compared with control siRNA. siRNA directed against TGFβ receptor 2 also decreased cell migration compared with control and decreased extracellular matrix genes regulated by TGFβ signaling. Elevated HP increased the expression of MYLK-130 and MYLK-210 in both populations of astrocytes. However, TGFβ2 was uniquely upregulated by exposure to elevated HP in CA compared with AA astrocytes. Conclusions. Differential expression of TGFβ pathway genes and MYLK isoforms observed in populations of glaucomatous astrocytes applies to the elevated HP model system. MYLK may be a new target for intervention in glaucoma to alter reactive astrocyte migration in the ONH. PMID:20375339

  17. Calcium regulation in frog peripheral nerve by the blood-nerve barrier

    SciTech Connect

    Wadhwani, K.C.

    1986-01-01

    The objectives of this research were: (a) to investigate the characteristics of calcium transport across the perineurium and the endoneurial capillaries, and (b) to gain a better understanding of the extent of calcium homeostasis in the endoneurial space. To study the nature of calcium transport across the perineurium, the flux of radiotracer /sup 45/Ca was measured through the perineurial cylinder, isolated from the frog sciatic nerve, and through the perineurium into the nerve in situ. To study the nature of calcium transport across the endoneurial capillaries, the permeability-surface area product (PA) of /sup 45/Ca was determined as a function of the calcium concentration in the blood. To study calcium homeostasis, the calcium content of the frog sciatic nerve was determined as a function of chronic changes in plasma (Ca).

  18. Cerebral blood flow changes during vagus nerve stimulation for depression.

    PubMed

    Conway, Charles R; Sheline, Yvette I; Chibnall, John T; George, Mark S; Fletcher, James W; Mintun, Mark A

    2006-03-31

    Positron emission tomography (PET oxygen-15 labeled water or PET [15O]H2O) was used to identify changes in regional cerebral blood flow (rCBF) in response to acute vagus nerve stimulation (VNS) in four subjects with treatment-resistant major depression (TRMD). Four 90-s PET [15O]H2O scans were performed on each subject in an off-on sequence (2 VNS de-activated; 2 VNS activated). PET images were aligned, normalized for global uptake, and resampled to standard atlas space. Statistical t-images were used to evaluate change. VNS-induced increases in rCBF were found in the bilateral orbitofrontal cortex, bilateral anterior cingulate cortex, and right superior and medial frontal cortex. Decreases were found in the bilateral temporal cortex and right parietal area. Regions of change were consistent with brain structures associated with depression and the afferent pathways of the vagus nerve. PMID:16510266

  19. Schlieren laser Doppler flowmeter for the human optical nerve head with the flicker stimuli.

    PubMed

    Geiser, Martial H; Truffer, Frederic; Evequoz, Hugo; Khayi, Hafid; Mottet, Benjamin; Chiquet, Christophe

    2013-12-01

    We describe a device to measure blood perfusion for the human optic nerve head (ONH) based on laser Doppler flowmetry (LDF) with a flicker stimuli of the fovea region. This device is self-aligned for LDF measurements and includes near-infrared pupil observation, green illumination, and observation of the ONH. The optical system of the flowmeter is based on a Schlieren arrangement which collects only photons that encounter multiple scattering and are back-scattered out of the illumination point. LDF measurements are based on heterodyne detection of Doppler shifted back-scattered light. We also describe an automated analysis of the LDF signals which rejects artifacts and false signals such as blinks. By using a Doppler simulator consisting of a lens and a rotating diffusing wheel, we demonstrate that velocity and flow vary linearly with the speed of the wheel. A cohort of 12 healthy subjects demonstrated that flicker stimulation induces an increase of 17.8% of blood flow in the ONH. PMID:24296999

  20. Feasibility of an endoscopic approach to the axillary nerve and the nerve to the long head of the triceps brachii with the help of the Da Vinci Robot.

    PubMed

    Porto de Melo, P M; Garcia, J C; Montero, E F de Souza; Atik, T; Robert, E-G; Facca, S; Liverneaux, P-A

    2013-09-01

    Surgery to transfer the axillary nerve and the nerve of the long head of the triceps presents two obstacles: 1) the access portals are not standardized and 2) the nerves are for their larger part approached through large incisions. The goal of this study was to explore the feasibility of an endoscopic microsurgical approach. The posterior aspect of a cadaver shoulder was approached through three communicating mini-incisions. The Da Vinci robot camera was installed on a central trocart, and the instrument arms on the adjacent trocarts. A gas insufflation distended the soft tissues up to the lateral axillary space. The branches of the axillary nerve and the nerve to the long head of the triceps brachii muscle were identified. The dissection of the axillary nerve trunk and its branches was easy. The posterior humeral circumflex veins and artery were dissected as well without any difficulty. Finding the nerve to the long head of the triceps brachii was found to be more challenging because of its deeper location. Robots properties allow performing conventional microsurgery: elimination of the physiologic tremor and multiplication of the movements. They also facilitate the endoscopic approach of the peripheral nerves, as seen in our results on the terminal branches of the axillary nerve and the nerve to the long head of the triceps brachii. PMID:23867724

  1. Alterations of sympathetic nerve fibers in avascular necrosis of femoral head

    PubMed Central

    Li, Deqiang; Liu, Peilai; Zhang, Yuankai; Li, Ming

    2015-01-01

    Objectives: Avascular necrosis of the femoral head (ANFH) was mainly due to alterations of bone vascularity. And noradrenaline (NA), as the neurotransmitter of the sympathetic nervous system (SNS), leads to the vasoconstriction by activating its α-Receptor. This study was to explore the nerve fiber density of the femoral head in the rabbit model of ANFH. Methods: Twenty New Zealand white rabbits were used in this study. The rabbit model of ANFH was established by the injection of methylprednisolone acetate. The nerve fiber density and distribution in the femoral head was determined using an Olympus BH2 microscope. Results: Significant fewer sympathetic nerve fibers was found in the ANFH intertrochanteric bone samples (P = 0.036) with osteonecrosis. The number of sympathetic nerve fibers was compared between the two groups. And less sympathetic nerve fibers were found in later stage ANFH samples in comparison with those of early stages. Conclusions: ANFH might be preceded by an inflammatory reaction, and an inflammatory response might lead to arthritic changes in tissue samples, which in turn reduces the number of sympathetic nerve fibers. PMID:26617812

  2. Isolated unilateral hypoglossal nerve palsy after minor head trauma.

    PubMed

    Kaushik, Vivek; Kelly, Gerard; Richards, Stuart D; Saeed, Shakeel R

    2002-12-01

    Isolated unilateral hypoglossal nerve palsy after fracture of the occipital condyle is rare. It usually occurs after major trauma, such as high-speed deceleration injuries following road traffic accidents. We describe a case that resulted from minor trauma. An underlying skull base malformation may have been a predisposing factor. PMID:12445924

  3. Autonomic Nerve Activity and Blood Pressure in Ambulatory Dogs

    PubMed Central

    Hellyer, Jessica; Akingba, A. George; Rhee, Kyoung-Suk; Tan, Alex Y.; Lane, Kathleen A.; Shen, Changyu; Patel, Jheel; Fishbein, Michael C; Chen, Peng-Sheng

    2014-01-01

    Background The relationship between cardiac autonomic nerve activity and blood pressure (BP) changes in ambulatory dogs is unclear. Objective To test the hypotheses that simultaneous termination of stellate ganglion nerve activity (SGNA) and vagal nerve activity (VNA) predisposes to spontaneous orthostatic hypotension and that specific β2 adrenoceptor blockade prevents the hypotensive episodes. Methods We used a radiotransmitter to record SGNA, VNA and blood pressure (BP) in 8 ambulatory dogs. Video imaging was used to document postural changes. Results Out of these 8 dogs, 5 showed simultaneous sympathovagal discharges in which the minute by minute integrated SGNA correlated with integrated VNA in a linear pattern (“Group 1”). In these dogs abrupt termination of simultaneous SGNA-VNA at the time of postural changes (as documented by video imaging) was followed by abrupt (>20 mmHg over 4 beats) drops in BP. Dogs without simultaneous on/off firing (“Group 2”) did not have drastic drops in pressure. ICI 118,551 (ICI, a specific β2-blocker) infused at 3.1 µg/kg/hr for 7 days significantly increased BP from 126 (95% confidence interval, CI: 118 to 133) mmHg to 133 (95% CI 125 to141) mmHg (p=0.0001). The duration of hypotension (mean systolic BP < 100 mmHg) during baseline accounted for 7.1% of the recording. The percentage was reduced by ICI to 1.3% (p = 0.01). Conclusions Abrupt simultaneous termination of SGNA-VNA was observed at the time of orthostatic hypotension in ambulatory dogs. Selective β2 adrenoceptor blockade increased BP and reduced the duration of hypotension in this model. PMID:24275433

  4. Longitudinal Hemodynamic Changes Within the Optic Nerve Head in Experimental Glaucoma

    PubMed Central

    Cull, Grant; Burgoyne, Claude F.; Fortune, Brad; Wang, Lin

    2013-01-01

    Purpose. To characterize longitudinal changes in basal blood flow (BF) of the optic nerve head (ONH) during progression of structural damage in experimental glaucoma (EG). Methods. Unilateral elevation of IOP was induced in 15 adult rhesus macaques by laser treatment to the trabecular meshwork. Prior to and after laser, retinal nerve fiber layer thickness (RNFLT) and ONH BF were measured biweekly by spectral-domain optical coherence tomography and a laser speckle flowgraphy device (LSFG), respectively. Results. Average postlaser IOP was 20.2 ± 5.9 mm Hg in EG eyes and 12.3 ± 2.6 mm Hg in control eyes (P < 0.0001). Longitudinal changes in basal ONH BF were strongly associated with changes in RNFLT as EG progressed from early through moderately advanced stages of damage, with Pearson correlation coefficients ranging from 0.64 to 0.97 (average = 0.81) and an average slope of 1.0. During early stage (RNFLT loss < 10%), basal ONH BF was mildly increased (9% ± 10%, P = 0.004) relative to baseline and compared with fellow controls (P = 0.02). Basal ONH BF declined continuously throughout subsequent stages in EG eyes reaching 25.0% ± 9.6% (P < 0.0001) below baseline at the final stage studied (RNFLT loss > 40%). In fellow control eyes, there was no significant change in basal ONH BF over time (P = 0.27). Conclusions. In EG based on chronic mild-to-moderate IOP elevation, a two-phase pattern of ONH BF alteration was observed. ONH BF increased during the earliest stage (while RNFLT was within 10% of baseline) followed by a linear decline that was strongly correlated with loss of RNFLT. PMID:23737471

  5. The concept and controversy of retroperitoneal nerve dissection in pancreatic head carcinoma (Review).

    PubMed

    Wang, Xuan; Zhang, Hongwei; Wang, Taihong; Lau, Wan Yee; Wang, Xin; Sun, Jingfeng; Yuan, Zhenhua; Zhang, Yewei

    2015-12-01

    Pancreatic head cancer is a common but the most lethal cancer of the human digestive system. It is invasive, resulting in early infiltration of adjacent structures and lymph node and distant metastases. Its biological characteristics of neurotropic growth lead to early neural invasion (NI) which is an independent prognostic factor of survival for pancreatic cancer. Radical surgical resection remains the only form of curative treatment. The extent of surgical resection and whether extended resection results in better long-term survival have been controversial. Studies have reported that peripancreatic plexus invasion is a frequent cause of pancreatic cancer recurrence and death. The relationship between cancer microenvironment and nerve cells, and whether the peripancreatic nerve plexus nearby needs to be resected require further studies. The present review aims to discuss the role of peripancreatic nerve and its implications in pancreatic head cancer resection. PMID:26458369

  6. Natural motion of the optic nerve head revealed by high speed phase-sensitive OCT

    NASA Astrophysics Data System (ADS)

    OHara, Keith; Schmoll, Tilman; Vass, Clemens; Leitgeb, Rainer A.

    2013-03-01

    We use phase-sensitive optical coherence tomography (OCT) to measure the deformation of the optic nerve head during the pulse cycle, motivated by the possibility that these deformations might be indicative of the progression of glaucoma. A spectral-domain OCT system acquired 100k A-scans per second, with measurements from a pulse-oximeter recorded simultaneously, correlating OCT data to the subject's pulse. Data acquisition lasted for 2 seconds, to cover at least two pulse cycles. A frame-rate of 200-400 B-scans per second results in a sufficient degree of correlated speckle between successive frames that the phase-differences between fames can be extracted. Bulk motion of the entire eye changes the phase by several full cycles between frames, but this does not severely hinder extracting the smaller phase-changes due to differential motion within a frame. The central cup moves about 5 μm/s relative to the retinal-pigment-epithelium edge, with tissue adjacent to blood vessels showing larger motion.

  7. Repeatability and reproducibility of optic nerve head perfusion measurements using optical coherence tomography angiography

    NASA Astrophysics Data System (ADS)

    Chen, Chieh-Li; Bojikian, Karine D.; Xin, Chen; Wen, Joanne C.; Gupta, Divakar; Zhang, Qinqin; Mudumbai, Raghu C.; Johnstone, Murray A.; Chen, Philip P.; Wang, Ruikang K.

    2016-06-01

    Optical coherence tomography angiography (OCTA) has increasingly become a clinically useful technique in ophthalmic imaging. We evaluate the repeatability and reproducibility of blood perfusion in the optic nerve head (ONH) measured using optical microangiography (OMAG)-based OCTA. Ten eyes from 10 healthy volunteers are recruited and scanned three times with a 68-kHz Cirrus HD-OCT 5000-based OMAG prototype system (Carl Zeiss Meditec Inc., Dublin, California) centered at the ONH involving two separate visits within six weeks. Vascular images are generated with OMAG processing by detecting the differences in OCT signals between consecutive B-scans acquired at the same retina location. ONH perfusion is quantified as flux, vessel area density, and normalized flux within the ONH for the prelaminar, lamina cribrosa, and the full ONH. Coefficient of variation (CV) and intraclass correlation coefficient (ICC) are used to evaluate intravisit and intervisit repeatability, and interobserver reproducibility. ONH perfusion measurements show high repeatability [CV≤3.7% (intravisit) and ≤5.2% (intervisit)] and interobserver reproducibility (ICC≤0.966) in all three layers by three metrics. OCTA provides a noninvasive method to visualize and quantify ONH perfusion in human eyes with excellent repeatability and reproducibility, which may add additional insight into ONH perfusion in clinical practice.

  8. Chronic Posttraumatic Dislocation of Radial Head With Ulnar Nerve Entrapment in a Child: A Case Report and Literature Review.

    PubMed

    Cai, Jiangyu; Wang, Wei; Yu, Shiyang; Yan, Hede; Zhan, Yulin; Fan, Cunyi

    2016-06-01

    We present an unusual case of chronic posttraumatic anteromedial dislocation of radial head with direct ulnar nerve entrapment in a child. Ulnar nerve decompression, open reduction of the radial head, and annular ligament reconstruction using a palmaris longus tendon graft were performed, and a satisfactory functional outcome was achieved at the 15-month follow-up. Through a review of literature, we conclude that early diagnosis and management for radial head dislocation are recommended to avoid nerve symptoms. Besides, open reduction and annular ligament reconstruction with a palmaris longus tendon graft would be an alternative surgery during chronic phase. PMID:27171922

  9. Tardy ulnar nerve palsy caused by chronic radial head dislocation after Monteggia fracture: a report of two cases.

    PubMed

    Nishimura, Masahiro; Itsubo, Toshiro; Horii, Emiko; Hayashi, Masanori; Uchiyama, Shigeharu; Kato, Hiroyuki

    2016-09-01

    Dislocation of the radial head is often encountered as a result of a pediatric Monteggia fracture. We report two rare cases of tardy ulnar nerve palsy associated with anterior radial head dislocation combined with anterior bowing of the ulna. They had cubitus valgus deformity, valgus instability, and osteoarthritis of the elbow, and had elbow injury more than 40 years back. They were diagnosed with chronic radial head dislocation long after a Bado type 1 Monteggia fracture. Anterior subcutaneous ulnar nerve transposition yielded favorable results. It is important to recognize the possibility of tardy ulnar nerve palsy caused by an improperly treated Monteggia fracture. PMID:26986030

  10. Isolation of intact astrocytes from the optic nerve head of adult mice

    PubMed Central

    Choi, Hee Joo; Sun, Daniel; Jakobs, Tatjana C.

    2015-01-01

    The astrocytes of the optic nerve head are a specialized subtype of white matter astrocytes that form the direct cellular environment of the unmyelinated ganglion cell axons. Due to their potential involvement in glaucoma, these astrocytes have become a target of research. Due to the heterogeneity of the optic nerve tissue, which also contains other cell types, in some cases it may be desirable to conduct gene expression studies on small numbers of well-characterized astrocytes or even individual cells. Here, we describe a simple method to isolate individual astrocytes. This method permits obtaining astrocytes with intact morphology from the adult mouse optic nerve and reduces contamination of the isolated astrocytes by other cell types. Individual astrocytes can be recognized by their morphology and collected under microscopic control. The whole procedure can be completed in 2-3 hours. We also discuss downstream applications like multiplex single-cell PCR and quantitative PCR (qPCR). PMID:26093274

  11. Aminoguanidine effects on nerve blood flow, vascular permeability, electrophysiology, and oxygen free radicals

    SciTech Connect

    Kihara, Mikihiro; Schmelzer, J.D.; Poduslo, J.F.; Curran, G.L.; Nickander, K.K.; Low, P.A. )

    1991-07-15

    Since advanced glycosylation end products have been suggested to mediate hyperglycemia-induced microvascular atherogenesis and because aminoguanidine (AG) prevents their generation, the authors examined whether AG could prevent or ameliorate the physiologic and biochemical indices of streptozotocin (STZ)-induced experimental diabetic neuropathy. Four groups of adult Sprague-Dawley rats were studied: group I received STZ plus AG, group II received STZ plus AG, group III received STZ alone, and group IV was a control. They monitored conduction and action potential amplitudes serially in sciatic-tibial and caudal nerves, nerve blood flow, oxygen free radical activity (conjugated dienes and hydroperoxides), and the product of the permeability coefficient and surface area to {sup 125}I-labeled albumin. STZ-induced diabetes (group III) caused a 57% reduction in nerve blood flow and in abnormal nerve conduction and amplitudes and a 60% increase in conjugated dienes. Nerve blood flow was normalized by 8 weeks with AG (groups I and II) and conduction was significantly improved, in a dose-dependent manner, by 16 and 24 weeks in sciatic-tibial and caudal nerves, respectively. The permeability coefficient was not impaired, suggesting a normal blood-nerve barrier function for albumin, and the oxygen free-radical indices were not ameliorated by AG. They suggest that AG reverses nerve ischemia and more gradually improves their electrophysiology by an action on nerve microvessels. AG may have potential in the treatment of diabetic neuropathy.

  12. Effect of head tilt on repeatability of optic nerve head parameters using cirrus spectral-domain optical coherence tomography

    PubMed Central

    Koh, Lilian Hui Li; Ismail, Muhammad Amir; Yap, Sae Cheong; Wong, Elizabeth Poh Ying; Yip, Leonard Wei Leon

    2016-01-01

    AIM To assess the repeatability of measuring optic nerve head (ONH) parameters using the Cirrus optical coherence tomography (OCT), as well as to assess the effect of head tilt on these measurements. METHODS Thirty healthy participants with no evidence of glaucoma were recruited for the study. Visual acuity, intraocular pressure, standard automated perimetry and ocular examination were performed for each participant. One eye was then randomly selected and scanned undilated with the Cirrus OCT in 3 positions (neutral, 30° right tilt and 30° left tilt). RESULTS Data collected from 29 eyes were used for analysis. One patient was omitted due to poor scan quality. The repeatability of the ONH parameters was analyzed using analysis of variance, coefficient of variation (COV) and intraclass correlation coefficient (ICC). Analysis of variance showed no statistically significant difference between 3 scans in a single position. There was good agreement between measurements (ICC 0.919-0.996, COV 1.94%-5.48%). Even with the presence of head tilt, repeated scans in the 3 positions showed good agreement as well (ICC 0.888-0.996, COV 2.04%-5.39%). CONCLUSION Serial measurements of ONH parameters using the Cirrus OCT are found to have good repeatability. The ONH parameters with Cirrus OCT also maintain good repeatability despite head tilt. PMID:27585788

  13. Assessment of the Optic Nerve Head Parameters Using Heidelberg Retinal Tomography III in Preterm Children

    PubMed Central

    Alshaarawi, Salem; Shatriah, Ismail; Zunaina, Embong; Wan Hitam, Wan Hazabbah

    2014-01-01

    Background Variations in optic nerve head morphology and abnormal retinal vascular pattern have been described in preterm children using digital image analysis of fundus photograph, optical coherence tomograph and serial funduscopy. We aimed to compare the optic nerve head parameters in preterm and term Malay children using Heidelberg Retinal Tomograph III. Design A cross sectional study. Methodology/Principal Findings Thirty-two preterm Malay children who were born at up to 32 weeks postconception, and 32 term Malay children aged 8–16 years old were recruited into this cross sectional study, which was conducted in the Hospital Universiti Sains Malaysia, Malaysia from January to December 2011. Their optic nerves were scanned and analyzed using a Heidelberg Retinal Tomography (HRT) III (Heidelberg Engineering, Germany). Preterm children showed an increased rim volume (SD) (0.56 (0.26) vs 0.44 (0.18) mm3, respectively), smaller cup shape (SD) (0.18 (0.07) vs 0.25 (0.06) mm, respectively), increased height variation contour (SD) (0.44 (0.14) vs 0.35 (0.08) mm, respectively), and increased cup depth (SD) (0.24 (0.11) vs 0.17 (0.05) mm3, respectively) when compared to their normal peers (p<0.05). There were no significant differences in the mean disc area, cup area, cup to disc ratio or rim area between the preterm and term children (p>0.05) in our study. Conclusions/Significance Preterm children exhibit different characteristics of optic nerve head parameters with HRT III analysis. Increased cup depth in preterm children suggests a need for close observation and monitoring. It may raise suspicion of pediatric glaucoma when proper documentation of intraocular pressure and clinical funduscopy are unsuccessful in uncooperative children. PMID:24551076

  14. Evaluation of optic disc size in patients with optic nerve head drusen using fundus photography

    PubMed Central

    Gili, Pablo; Flores-Rodríguez, Patricia; Yangüela, Julio; Orduña-Azcona, Javier; Martín-Ríos, María Dolores

    2012-01-01

    Purpose To evaluate if fundus photography is useful to study the size of the optic disc in patients with optic nerve head drusen (ONHD). Methods Cross-sectional study. Fifty-five patients with ONHD confirmed by B-scan echography and 52 patients’ normal controls were studied. Fundus photography was done in all the cases with a telecentric optical system FF450 IR plus from Zeiss with 20° magnification and Visupac measuring system. We measured total optic disc area, vertical and horizontal diameter. Results Patients with ONHD had smaller optic disc area 2.6 ± 0.55 mm2 (mean ± SD), horizontal diameter (1.68 ± 0.18 mm) and vertical diameter (1.94 ± 0.28 mm) than normal controls (2.93 ± 0.43 mm2, 1.86 ± 0.14 mm and 1.98 ± 0.17 mm, respectively). Significant differences were found in area (p = 0.002) and horizontal diameter (p < 0.001). Conclusions Patients with optic nerve head drusen had smaller optic disc size than normal controls, under digital fundus photography. Fundus photography could be helpful to differentiate optic nerve drusen from other ocular conditions.

  15. Plate reader-based cell viability assays for glioprotection using primary rat optic nerve head astrocytes

    PubMed Central

    Kaja, Simon; Payne, Andrew J.; Naumchuk, Yuliya; Levy, Deborah; Zaidi, Danish H.; Altman, Alexa M.; Nawazish, Saba; Ghuman, Jasleen K.; Gerdes, Bryan C.; Moore, Mark A.; Koulen, Peter

    2015-01-01

    Optic nerve head astrocytes (ONHAs) are the major glia cell type in the non-myelinated optic nerve head where they contribute critically to extracellular matrix synthesis during development and throughout life. In glaucoma, and in related disorders affecting the optic nerve and the optic nerve head, pathological changes include altered astrocyte gene and protein expression resulting in their activation and extracellular matrix remodeling. ONHAs are highly sensitive to mechanical and oxidative stress resulting in the initiation of axon damage early during pathogenesis. Furthermore, ONHAs are crucial for the maintenance of retinal ganglion cell physiology and function. Therefore, glioprotective strategies with the goal to preserve and/or restore the structural and functional viability of ONHA in order to slow glaucoma and related pathologies are of high clinical relevance. Herein, we describe the development of standardized methods that will allow for the systematic advancement of such glioprotective strategies. These include isolation, purification and culture of primary adult rat ONHAs, optimized immunocytochemical protocols for cell type validation, as well as plate reader-based assays determining cellular viability, proliferation and the intracellular redox state. We validated and standardized our protocols by performing a glioprotection study using primary ONHAs. Specifically, we measured protection against exogenously-applied oxidative stress using tert-butylhydroperoxide (tBHP) as a model of disease-mediated oxidative stress in the retina and optic nerve head by the prototypic antioxidant, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox). Levels of oxidative stress were increased in the response to exogenously applied tBHP and were assessed by 6-carboxy-2′, 7′ dichlorodihydrofluorescein diacetate (DCFDA) fluorescence. Normalized DCFDA fluorescence showed a maximal 5.1-fold increase; the half-maximal effect (EC50) for tBHP was 212 ± 25

  16. Relations of blood pressure and head injury to regional cerebral blood flow.

    PubMed

    Kisser, Jason E; Allen, Allyssa J; Katzel, Leslie I; Wendell, Carrington R; Siegel, Eliot L; Lefkowitz, David; Waldstein, Shari R

    2016-06-15

    Hypertension confers increased risk for cognitive decline, dementia, and cerebrovascular disease. These associations have been attributed, in part, to cerebral hypoperfusion. Here we posit that relations of higher blood pressure to lower levels of cerebral perfusion may be potentiated by a prior head injury. Participants were 87 community-dwelling older adults - 69% men, 90% white, mean age=66.9years, 27.6% with a history of mild traumatic brain injury (mTBI) defined as a loss of consciousness ≤30min resulting from an injury to the head, and free of major medical (other than hypertension), neurological or psychiatric comorbidities. All engaged in clinical assessment of systolic and diastolic blood pressure (SBP, DBP) and single photon emission computed tomography (SPECT). Computerized coding of the SPECT images yielded relative ratios of blood flow in left and right cortical and select subcortical regions. Cerebellum served as the denominator. Sex-stratified multiple regression analyses, adjusted for age, education, race, alcohol consumption, smoking status, and depressive symptomatology, revealed significant interactions of blood pressure and head injury to cerebral blood flow in men only. Specifically, among men with a history of head injury, higher systolic blood pressure was associated with lower levels of perfusion in the left orbital (β=-3.21, p=0.024) and left dorsolateral (β=-2.61, p=0.042) prefrontal cortex, and left temporal cortex (β=-3.36, p=0.014); higher diastolic blood pressure was marginally associated with lower levels of perfusion in the left dorsolateral prefrontal cortex (β=-2.79, p=0.051). Results indicate that men with a history of head injury may be particularly vulnerable to the impact of higher blood pressure on cerebral perfusion in left anterior cortical regions, thus potentially enhancing risk for adverse brain and neurocognitive outcomes. PMID:27206865

  17. A biomechanical paradigm for axonal insult within the optic nerve head in aging and glaucoma.

    PubMed

    Burgoyne, Claude F

    2011-08-01

    This article is dedicated to Rosario Hernandez for her warm support of my own work and her genuine enthusiasm for the work of her colleagues throughout her career. I first met Rosario as a research fellow in Harry Quigley's laboratory between 1991 and 1993. Along with Harry, John Morrison, Elaine Johnson, Abe Clark, Colm O'Brien and many others, Rosario's work has provided lamina cribrosa astrocyte cellular mechanisms that are biomechanically plausible and in so doing provided credibility to early notions of the optic nerve head (ONH) as a biomechanical structure. We owe a large intellectual debt to Rosario for her dogged persistence in the characterization of the ONH astrocyte and lamina cribrosacyte in age and disease. Two questions run through her work and remain of central importance today. First, how do astrocytes respond to and alter the biomechanical environment of the ONH and the physiologic stresses created therein? Second, how do these physiologic demands on the astrocyte influence their ability to deliver the support to retinal ganglion cell axon transport and flow against the translaminar pressure gradient? The purpose of this article is to summarize what is known about the biomechanical determinants of retinal ganglion cell axon physiology within the ONH in the optic neuropathy of aging and Glaucoma. My goal is to provide a biomechanical framework for this discussion. This framework assumes that the ONH astrocytes and glia fundamentally support and influence both the lamina cribrosa extracellular matrix and retinal ganglion cell axon physiology. Rosario Hernandez was one of the first investigators to recognize the implications of this unique circumstance. Many of the ideas contained herein have been initially presented within or derived from her work (Hernandez, M.R., 2000. The optic nerve head in glaucoma: role of astrocytes in tissue remodeling. Prog Retin Eye Res. 19, 297-321.; Hernandez, M.R., Pena, J.D., 1997. The optic nerve head in glaucomatous

  18. Evaluation of Multiple Blood Matrices for Assessment of Human Exposure to Nerve Agents.

    PubMed

    Schulze, Nicholas D; Hamelin, Elizabeth I; Winkeljohn, W Rucks; Shaner, Rebecca L; Basden, Brian J; deCastro, B Rey; Pantazides, Brooke G; Thomas, Jerry D; Johnson, Rudolph C

    2016-04-01

    Biomedical samples may be used to determine human exposure to nerve agents through the analysis of specific biomarkers. Samples received may include serum, plasma, whole blood, lysed blood and, due to the toxicity of these compounds, postmortem blood. To quantitate metabolites resulting from exposure to sarin (GB), soman (GD), cyclosarin (GF), VX and VR, these blood matrices were evaluated individually for precision, accuracy, sensitivity and specificity. Accuracies for these metabolites ranged from 100 to 113% with coefficients of variation ranging from 2.31 to 13.5% across a reportable range of 1-100 ng/mL meeting FDA recommended guidelines for bioanalytical methods in all five matrices. Limits of detection were calculated to be 0.09-0.043 ng/mL, and no interferences were detected in unexposed matrix samples. The use of serum calibrators was also determined to be a suitable alternative to matrix-matched calibrators. Finally, to provide a comparative value between whole blood and plasma, the ratio of the five nerve agent metabolites measured in whole blood versus plasma was determined. Analysis of individual whole blood samples (n = 40), fortified with nerve agent metabolites across the reportable range, resulted in average nerve agent metabolite blood to plasma ratios ranging from 0.53 to 0.56. This study demonstrates the accurate and precise quantitation of nerve agent metabolites in serum, plasma, whole blood, lysed blood and postmortem blood. It also provides a comparative value between whole blood and plasma samples, which can assist epidemiologists and physicians with interpretation of test results from blood specimens obtained under variable conditions. PMID:26861671

  19. Comparison of cutaneous nerve injury and vessel disruption complications following saphenous vein stripping using big or small olive heads

    PubMed Central

    Cicek, Mustafa Cuneyt; Cicek, Omer Faruk; Lafci, Gokhan; Uzun, Alper

    2016-01-01

    Objective: To compare the nerve injury and vessel disruption complicaitons in patients undergoing saphenous vein stripping using olive heads of different sizes. Methods: Big olive heads were used in group A (n=50) and small olive heads were used in group B (n=50) from the ankle to the groin; in group C (n=50), the vein was stripped in two sections; in an upward fashion by stripping the distal portion from the ankle to the level of the knee using small olive heads and by stripping the proximal portion from the knee to the level of the groin using big olive heads. Results: Six months after the operation, nerve injury symptoms were identified in 26%, 4%, 6% of patients in groups A, B, and C respectively. Vessel disruption occurred 2% in group A, 32% in group B, and 4% in group C. Both vessel disruption and nerve injury complications of group C were significantly lower than group A and B (p<0.001). Conclusion: Saphenous stripping using big olive heads for the proximal portion from the groin down to the level of the knee and using small olive heads for the distal portion from the knee to the level of the ankle is the alternative method which results in minimal nerve injury and vessel disruption. PMID:27375703

  20. Basal Blood Flow and Autoregulation Changes in the Optic Nerve of Rhesus Monkeys with Idiopathic Bilateral Optic Atrophy

    PubMed Central

    Piper, Chelsea; Fortune, Brad; Cull, Grant; Cioffi, George A.; Wang, Lin

    2013-01-01

    Purpose. To characterize the hemodynamic features and the association with structural damage in the optic nerve head (ONH) of idiopathic bilateral optic atrophy (BOA) in rhesus macaque monkeys. Methods. In five animals with BOA and nine healthy animals under general anesthesia (pentobarbital), intraocular pressure (IOP) was manometrically controlled. ONH blood flow was measured with a laser speckle flow graph device. Basal blood flow in global and quadrantal sectors was measured with IOP set at 10 mm Hg; autoregulation capacity was assessed by comparing blood flow changes before and after IOP was increased from 10 to 30 mm Hg. Spectral-domain optic coherence tomography was used to measure retinal nerve fiber layer thickness (RNFLT) by peripapillary circular scans. Results. Compared with control eyes, RNFLT in BOA eyes was significantly less in all sectors (P < 0.001) except the nasal (P = 0.25); the average global and sectoral blood flow in all quadrants was significantly lower (P < 0.001). These blood flow changes were significantly correlated with corresponding sectoral RNFLT (P < 0.01) except the nasal (P = 0.25). After IOP was increased to 30 mm Hg, global blood flow was significantly reduced (P < 0.001), but with no regional preferences despite prominent temporal RNFLT loss; no significant blood flow change was observed in control eyes (P = 0.24). Conclusions. Basal blood flow and autoregulation capacity in the ONH of BOA were significantly compromised, with a close correlation to structural changes. The hemodynamic changes showed no regional preference across the ONH, which was consistent with postmortem histological observations. PMID:23287792

  1. Blood-nerve barrier in IgM paraproteinemic neuropathy: a clinicopathologic assessment.

    PubMed

    Kanda, T; Usui, S; Beppu, H; Miyamoto, K; Yamawaki, M; Oda, M

    1998-02-01

    We report the pathologic findings in a patient with sensorimotor neuropathy associated with Waldenström's macroglobulinemia, particularly in relation to blood-nerve barrier defects. The monoclonal IgM was of kappa type and possessed anti-HNK-1 activity. A sural nerve biopsy specimen revealed severe loss of myelinated and unmyelinated nerve fibers and gaps between adjacent endothelial cells of small endoneurial vessels. Postmortem findings 3 years later included severe loss of myelinated nerve fibers and diffuse infiltration by lymphoplasmacytic B cells throughout the peripheral nervous system, sparing the central nervous system. Findings in this case suggest an immune attack against endoneurial endothelial cells with permeation of IgM into peripheral nerve tissue. PMID:9498055

  2. Sequential-digital image correlation for mapping human posterior sclera and optic nerve head deformation.

    PubMed

    Pyne, Jeffrey D; Genovese, Katia; Casaletto, Luciana; Vande Geest, Jonathan P

    2014-02-01

    Optic nerve head (ONH) deformations may be involved in the onset or further development of glaucoma, including in patients with relatively normal intraocular pressures (IOPs). Characterizing posterior scleral deformations over physiological pressures may provide a better understanding of how changes in IOP lead to changes in the mechanical environment of the ONH and possibly retinal ganglion cell death. Pressure inflation measurement test protocols are commonly used to measure deformation of the peripapillary sclera with full-field noncontact optical methods. The purpose of this work was to develop and validate a new sequential 3D digital image correlation (S-DIC) approach for quantification of posterior scleral pressure induced deformation that improves z (in-depth) resolution of the DIC measurement without losing in-plane sensitivity, while also being able to contour and map deformations of the complex-shaped ONH. Our approach combines two orthogonal axes of parallax with standard 3D DIC methods using a single high-resolution camera. The enhanced capabilities of S-DIC with respect to standard 3D DIC has been demonstrated by carrying out a complete benchmark for shape, deformation, and strain measurement on an object of known complex geometry. Our S-DIC method provided a reconstruction accuracy of 0.17% and an uncertainty in z-position measurement of 8 μm. The developed methodology has also been applied to a human posterior scleral shell, including the full peripapillary sclera and optic nerve. The relatively inexpensive S-DIC approach may provide new information on the biomechanical deformations of the optic nerve head and, thus, the death of retinal ganglion cells in primary open angle glaucoma. PMID:24337344

  3. A study of the role of renal nerves in the renal responses to 60° head-up tilt in the anaesthetized dog

    PubMed Central

    DiBona, G. F.; Johns, E. J.

    1980-01-01

    1. Renal responses to 10 min of 60° head-up tilt were measured in anaesthetized dogs in which renal perfusion pressure was maintained at a relatively constant value. 2. Tilting was associated with a fall in systemic blood pressure and an increase in heart rate. Renal blood flow and glomerular filtration rate remained constant while there was a significant decrease in both absolute and fractional excretion of sodium. 3. Animals which had undergone acute renal denervation were tilted. The cardiovascular responses were similar to intact animals. A fall in renal blood flow was observed but the glomerular filtration rate was maintained at a steady value during tilting. The decreased renal tubular excretion of sodium measured in intact animals was abolished. 4. Alpha-adrenergic blockade of the kidney was achieved by infusion of phentolamine into the renal artery. Tilting of these animals caused cardiovascular changes similar to those observed in control animals but renal blood flow, glomerular filtration rate and sodium handling remained unchanged. 5. Animals in which both carotid sinuses had been acutely denervated were tilted. Systemic blood pressure fell as in intact animals, but the rise in heart rate was significantly less. Renal blood flow, glomerular filtration rate and the rate of sodium excretion were unchanged. 6. A 10 min period of 60° head-up tilt in anaesthetized dogs resulted in an unchanged renal blood flow and glomerular filtration rate which was associated with a decrease in both fractional excretion of sodium and sodium excretion. The renal sympathetic nerves were shown to be responsible for these changes in tubular sodium handling which appeared to exert their action via renal tubular α-adrenergic receptors. This activation of the renal nerves appeared to be mediated by the carotid sinus baroreceptor reflex. PMID:7381761

  4. Vaginal blood flow after radical hysterectomy with and without nerve sparing. A preliminary report.

    PubMed

    Pieterse, Q D; Ter Kuile, M M; Deruiter, M C; Trimbos, J B M Z; Kenter, G G; Maas, C P

    2008-01-01

    Radical hysterectomy with pelvic lymphadenectomy (RHL) for cervical cancer causes damage to the autonomic nerves, which are responsible for increased vaginal blood flow during sexual arousal. The aim of the study of which we now report preliminary data was to determine whether a nerve-sparing technique leads to an objectively less disturbed vaginal blood flow response during sexual stimulation. Photoplethysmographic assessment of vaginal pulse amplitude (VPA) during sexual stimulation by erotic films was performed. Subjective sexual arousal was assessed after each stimulus. Thirteen women after conventional RHL, 10 women after nerve-sparing RHL, and 14 healthy premenopausal women participated. Data were collected between January and August 2006. The main outcome measure was the logarithmically transformed mean VPA. To detect statistically significant differences in mean VPA levels between the three groups, a univariate analysis of variance was used. Mean VPA differed between the three groups (P= 0.014). The conventional group had a lower vaginal blood flow response than the control group (P= 0.016), which tended also to be lower than that of the nerve-sparing group (P= 0.097). These differences were critically dependent on baseline vaginal blood flow differences between the groups. The conventional group follows a vaginal blood flow pattern similar to postmenopausal women. Conventional RHL is associated with an overall disturbed vaginal blood flow response compared with healthy controls. Because it is not observed to the same extent after nerve-sparing RHL, it seems that the nerve-sparing technique leads to a better overall vaginal blood flow caused by less denervation of the vagina. PMID:17692083

  5. Automatic segmentation of the optic nerve head for deformation measurements in video rate optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Hidalgo-Aguirre, Maribel; Gitelman, Julian; Lesk, Mark Richard; Costantino, Santiago

    2015-11-01

    Optical coherence tomography (OCT) imaging has become a standard diagnostic tool in ophthalmology, providing essential information associated with various eye diseases. In order to investigate the dynamics of the ocular fundus, we present a simple and accurate automated algorithm to segment the inner limiting membrane in video-rate optic nerve head spectral domain (SD) OCT images. The method is based on morphological operations including a two-step contrast enhancement technique, proving to be very robust when dealing with low signal-to-noise ratio images and pathological eyes. An analysis algorithm was also developed to measure neuroretinal tissue deformation from the segmented retinal profiles. The performance of the algorithm is demonstrated, and deformation results are presented for healthy and glaucomatous eyes.

  6. Unilateral optic nerve head and choroidal metastases from a bronchial carcinoma.

    PubMed

    Hayreh, S S; Blodi, F C; Silbermann, N N; Summers, T B; Potter, P H

    1982-01-01

    A 61-year-old man presented with uniocular gradually progressive visual loss, pain in the eye, visual activity of 6/60, markedly constricted visual fields, optic disc edema, retinal pigment epithelial disturbance at the posterior pole, and markedly delayed filling of the choroid on angiography, with a normal fellow eye. He had suffered from recurrent seizures for 15 years, with some evidence of cortical demyelination. Erythrocyte sedimentation rate was elevated. About 5 months after the onset of visual disturbance, evidence of bronchial carcinoma became apparent and he died 6 weeks later. The etiology of his ocular lesions was established only by histopathological evidence of metastases into the optic nerve head and the choroid. Diagnostic problems presented by the ocular findings are discussed. PMID:7145334

  7. Automatic segmentation of the optic nerve head for deformation measurements in video rate optical coherence tomography.

    PubMed

    Hidalgo-Aguirre, Maribel; Gitelman, Julian; Lesk, Mark Richard; Costantino, Santiago

    2015-11-01

    Optical coherence tomography (OCT) imaging has become a standard diagnostic tool in ophthalmology, providing essential information associated with various eye diseases. In order to investigate the dynamics of the ocular fundus, we present a simple and accurate automated algorithm to segment the inner limiting membrane in video-rate optic nerve head spectral domain (SD) OCT images. The method is based on morphological operations including a two-step contrast enhancement technique, proving to be very robust when dealing with low signal-to-noise ratio images and pathological eyes. An analysis algorithm was also developed to measure neuroretinal tissue deformation from the segmented retinal profiles. The performance of the algorithm is demonstrated, and deformation results are presented for healthy and glaucomatous eyes. PMID:26598974

  8. Estimating a structural bottle neck for eye-brain transfer of visual information from 3D-volumes of the optic nerve head from a commercial OCT device

    NASA Astrophysics Data System (ADS)

    Malmberg, Filip; Sandberg-Melin, Camilla; Söderberg, Per G.

    2016-03-01

    The aim of this project was to investigate the possibility of using OCT optic nerve head 3D information captured with a Topcon OCT 2000 device for detection of the shortest distance between the inner limit of the retina and the central limit of the pigment epithelium around the circumference of the optic nerve head. The shortest distance between these boundaries reflects the nerve fiber layer thickness and measurement of this distance is interesting for follow-up of glaucoma.

  9. Bilateral optic nerve head drusen with chorioretinal coloboma in the right eye.

    PubMed

    Dehghani, Ali Reza; Rezaei, Leila; Ghanbari, Heshmatollah

    2016-01-01

    Chorioretinal coloboma is a congenital defect of the eye caused by improper closure of the embryonic fissure. Optic nerve head drusen (ONHD) are white calcareous deposits that are generally asymptomatic. We report a very rare association of both in a healthy patient with no any systemic syndrome. A 16-year-old man was referred to our clinic from suffering blurred vision. Best corrected visual acuity of the right eye was 6/10 and 10/10 in the left one. External ocular and slit lamp examination were normal. Dilated ophthalmoscopy showed marked swelling in both optic nerves and chorioretinal coloboma in the right eye inferiorly. Ultrasonography showed an echodense structure with acoustic shadowing in both eyes consistent with buried ONHD. Visual field testing showed normal field in the left eye and moderate superior field depression in the right eye corresponding to inferior coloboma in funduscopy. Results of general medical and neurologic, cardiologic, and other examinations were normal. To the best our knowledge combination of bilateral ONHD and unilateral chorioretinal coloboma in a healthy patient with no any systemic syndrome has not been published in the literature. We reported this very rare association and recommended examine eyes and other body organs. In such cases that coloboma is associated with ONHD, we should keep in mind Noonan syndrome. The diagnosis of Noonan syndrome is clinical and confirm by the consultant pediatricians and clinical geneticists. PMID:27099847

  10. Bilateral optic nerve head drusen with chorioretinal coloboma in the right eye

    PubMed Central

    Dehghani, Ali Reza; Rezaei, Leila; Ghanbari, Heshmatollah

    2016-01-01

    Chorioretinal coloboma is a congenital defect of the eye caused by improper closure of the embryonic fissure. Optic nerve head drusen (ONHD) are white calcareous deposits that are generally asymptomatic. We report a very rare association of both in a healthy patient with no any systemic syndrome. A 16-year-old man was referred to our clinic from suffering blurred vision. Best corrected visual acuity of the right eye was 6/10 and 10/10 in the left one. External ocular and slit lamp examination were normal. Dilated ophthalmoscopy showed marked swelling in both optic nerves and chorioretinal coloboma in the right eye inferiorly. Ultrasonography showed an echodense structure with acoustic shadowing in both eyes consistent with buried ONHD. Visual field testing showed normal field in the left eye and moderate superior field depression in the right eye corresponding to inferior coloboma in funduscopy. Results of general medical and neurologic, cardiologic, and other examinations were normal. To the best our knowledge combination of bilateral ONHD and unilateral chorioretinal coloboma in a healthy patient with no any systemic syndrome has not been published in the literature. We reported this very rare association and recommended examine eyes and other body organs. In such cases that coloboma is associated with ONHD, we should keep in mind Noonan syndrome. The diagnosis of Noonan syndrome is clinical and confirm by the consultant pediatricians and clinical geneticists. PMID:27099847

  11. Disruption of phase synchronization between blood pressure and muscle sympathetic nerve activity in postural vasovagal syncope

    PubMed Central

    Schwartz, Christopher E.; Lambert, Elisabeth; Medow, Marvin S.

    2013-01-01

    Withdrawal of muscle sympathetic nerve activity (MSNA) may not be necessary for the precipitous fall of peripheral arterial resistance and arterial pressure (AP) during vasovagal syncope (VVS). We tested the hypothesis that the MSNA-AP baroreflex entrainment is disrupted before VVS regardless of MSNA withdrawal using the phase synchronization between blood pressure and MSNA during head-up tilt (HUT) to measure reflex coupling. We studied eight VVS subjects and eight healthy control subjects. Heart rate, AP, and MSNA were measured during supine baseline and at early, mid, late, and syncope stages of HUT. Phase synchronization indexes, measuring time-dependent differences between MSNA and AP phases, were computed. Directionality indexes, indicating the influence of AP on MSNA (neural arc) and MSNA on AP (peripheral arc), were computed. Heart rate was greater in VVS compared with control subjects during early, mid, and late stages of HUT and significantly declined at syncope (P = 0.04). AP significantly decreased during mid, late, and syncope stages of tilt in VVS subjects only (P = 0.001). MSNA was not significantly different between groups during HUT (P = 0.700). However, the phase synchronization index significantly decreased during mid and late stages in VVS subjects but not in control subjects (P < .001). In addition, the neural arc was significantly affected more than the peripheral arc before syncope. In conclusion, VVS is accompanied by a loss of the synchronous AP-MSNA relationship with or without a loss in MSNA at faint. This provides insight into the mechanisms behind the loss of vasoconstriction and drop in AP independent of MSNA at the time of vasovagal faint. PMID:23934851

  12. Renal Nerve Stimulation-Induced Blood Pressure Changes Predict Ambulatory Blood Pressure Response After Renal Denervation.

    PubMed

    de Jong, Mark R; Adiyaman, Ahmet; Gal, Pim; Smit, Jaap Jan J; Delnoy, Peter Paul H M; Heeg, Jan-Evert; van Hasselt, Boudewijn A A M; Lau, Elizabeth O Y; Persu, Alexandre; Staessen, Jan A; Ramdat Misier, Anand R; Steinberg, Jonathan S; Elvan, Arif

    2016-09-01

    Blood pressure (BP) response to renal denervation (RDN) is highly variable and its effectiveness debated. A procedural end point for RDN may improve consistency of response. The objective of the current analysis was to look for the association between renal nerve stimulation (RNS)-induced BP increase before and after RDN and changes in ambulatory BP monitoring (ABPM) after RDN. Fourteen patients with drug-resistant hypertension referred for RDN were included. RNS was performed under general anesthesia at 4 sites in the right and left renal arteries, both before and immediately after RDN. RNS-induced BP changes were monitored and correlated to changes in ambulatory BP at a follow-up of 3 to 6 months after RDN. RNS resulted in a systolic BP increase of 50±27 mm Hg before RDN and systolic BP increase of 13±16 mm Hg after RDN (P<0.001). Average systolic ABPM was 153±11 mm Hg before RDN and decreased to 137±10 mm Hg at 3- to 6-month follow-up (P=0.003). Changes in RNS-induced BP increase before versus immediately after RDN and changes in ABPM before versus 3 to 6 months after RDN were correlated, both for systolic BP (R=0.77, P=0.001) and diastolic BP (R=0.79, P=0.001). RNS-induced maximum BP increase before RDN had a correlation of R=0.61 (P=0.020) for systolic and R=0.71 (P=0.004) for diastolic ABPM changes. RNS-induced BP changes before versus after RDN were correlated with changes in 24-hour ABPM 3 to 6 months after RDN. RNS should be tested as an acute end point to assess the efficacy of RDN and predict BP response to RDN. PMID:27432864

  13. Interaction of nanoparticles of ferric oxide with brain nerve terminals and blood platelets

    NASA Astrophysics Data System (ADS)

    Borisova, Tatiana; Krisanova, Natalia; Sivko, Roman; Borisov, Arseniy

    2012-07-01

    Nanoparticles of ferric oxide are the components of Lunar and Martian soil simulants. The observations suggest that exposure to Lunar soli simulant can be deleterious to human physiology and the components of lunar soil may be internalized by lung epithelium and may overcome the blood-brain barrier. The study focused on the effects of nanoparticles of ferric oxide on the functional state of rat brain nerve terminals (synaptosomes) and rabbit blood platelets. Using photon correlation spectroscopy, we demonstrated the binding of nanoparticles of ferric oxide with nerve terminals and platelets. Nanoparticles did not depolarize the plasma membrane of nerve terminals and platelets that was shown by fluorimetry with potential-sensitive fluorescent dye rhodamine 6G. Using pH-sensitive fluorescent dye acridine orange, we revealed that the acidification of synaptic vesicles of nerve terminals and secretory granules of platelets did not change in the presence of nanoparticles. The initial velocity of uptake of excitatory neurotransmitter glutamate was not influenced by nanoparticles of ferric oxide, whereas glutamate binding to nerve terminals was altered. Thus, it was suggested that nanoparticles of ferric oxide might disturb glutamate transport in the mammalian CNS.

  14. Onychophoran cephalic nerves and their bearing on our understanding of head segmentation and stem-group evolution of Arthropoda.

    PubMed

    Eriksson, B J; Budd, G E

    2000-07-01

    The extant Onychophora are basal representatives of the Arthropoda, resembling Cambrian arthropod stem-group fossils such as Aysheaia and other so-called lobopodians. They thus provide an important model system for early stages in arthropod evolution, especially those of the head. However, homologies between onychophoran and euarthropod head structures have remained uncertain, and previous descriptions of the onychophoran head are contradictory. Our investigation examines the cephalic nerves of two species of onychophoran using immunohistochemical and confocal laser scanning microscopical techniques. Our new reconstruction for the distribution of onychophoran cephalic nerves differs significantly from previous accounts. The so-called "labrum" of the Onychophora appears to be part of the pharynx, and any affinities to the various pre-oral outgrowths of crown-group arthropods referred to as hypostomata and/or labra can be ruled out. The innervation of the mouth is particularly noteworthy, as its nerves originate from three different regions of the brain, including the dorsum. This suggests that the mouth was primitively terminal/frontal, although subsequent ventral rotation of the mouth may have been parallelly achieved in Onychophora and in Euarthropoda. Our model allows the onychophoran cephalic nervous system to be interpreted as a modified circumoral nerve ring, similar to that seen in the nematodes and other cycloneuralians. We regard this as supporting the Ecdysozoa model of arthropod relationships. PMID:18088927

  15. Nitric oxide control of lower vertebrate blood vessels by vasomotor nerves.

    PubMed

    Donald, John A; Broughton, Brad R S

    2005-10-01

    In mammals, much is understood about the endothelial and neural NO control mechanisms in the vasculature. In contrast, NO control of blood vessels in lower vertebrates is poorly understood, with the majority of research focusing on the presence of an endothelial NO system; however, its presence remains controversial. This study examined the mechanisms by which NO regulates the large blood vessels of non-mammalian vertebrates. In all species examined, the arteries and veins contained a plexus of NOS-positive perivascular nerves that included nerve bundles and fine, varicose nerve terminals. However, in the large arteries and veins of various species of fishes and amphibians, no anatomical evidence was found for endothelial NOS using both NADPH-diaphorase and eNOS immunohistochemistry. In contrast, perinuclear NOS staining was readily apparent in blue-tongue lizard, pigeon and rat, which suggested that eNOS first appeared in reptiles. Physiological analysis of NO signalling in the vascular smooth muscle of short-finned eel and cane toad could not find any evidence for endothelial NO signalling. In contrast, it appears that activation of the nitrergic vasomotor nerves is responsible for NO control of the blood vessels. PMID:16139537

  16. Optical coherence tomography in papilledema and pseudopapilledema with and without optic nerve head drusen

    PubMed Central

    Bassi, Shikha Talwar; Mohana, Kuppuswamy Parthasarthy

    2014-01-01

    Aim: To compare the spectral domain optical coherence tomography (SD-OCT) findings of the optic disc and the peripapillary retina of patients with a true papilledema and pseudopapilledema with and without optic nerve head drusen (ONHD). Study Design: Retrospective Case Control Study. Subjects and Methods: Peripapillary retinal nerve fiber layer (PPRNFL) thickness as depicted by SD-OCT of 94 eyes of 66 patients with papilledema (30 eyes), pseudopapiledema (31 eyes), and normal controls (33 eyes) was analyzed. The mean RNFL thickness, total retinal thickness (TRT) at a superior and inferior edge of the disc and the quadrant wise topography of increased RNFL were compared in all three groups. Sensitivity, specificity, and area under the receiver operating characteristic curve (AROC) were calculated for all the parameters. Results: The median RNFL thickness was 185.4 (129.5–349.3 μm), 122.3 (109–156.3 μm) and 91.62 ± 7 μm in papilledema, pseudopapilledema, and controls, respectively. Papilledema group had thicker PPRNFL in all quadrants except temporal quadrant. TRT was thicker in papilledema and pseudopapilledema compared to controls. ONHD could be directly visualized as high reflective clumps in the sub-retinal space or the RNFL in 30 eyes. Increased RNFL thickness in all four quadrants was noted 43.3% in papilledema and 9.7% in pseudopapilledema. Normal RNFL thickness in all four quadrants was noted in 0% in papilledema and 32.3% in pseudopapilledema. Nasal RNFL had the highest AROC (0.792) indicating high diagnostic ability to differentiate papilledema from pseudopapilledema. Conclusion: SD-OCT can be used as a tool to differentiate between papilledema and pseudopapilledema. PMID:25579359

  17. Optical coherence tomography of the optic nerve head detects acute changes in intracranial pressure.

    PubMed

    Anand, Aashish; Pass, Anastas; Urfy, Mian Z; Tang, Rosa; Cajavilca, Christian; Calvillo, Eusebia; Suarez, Jose I; Venkatasubba Rao, Chethan P; Bershad, Eric M

    2016-07-01

    We aimed to determine if there are measurable objective changes in the optic nerve head (ONH) immediately after cerebrospinal fluid (CSF) drainage in a prospective case-series of five patients undergoing a clinically indicated lumbar puncture (LP) for diagnosis of idiopathic intracranial hypertension. A Cirrus high-definition optical coherence tomography machine (Carl Zeiss Meditec, Dublin, CA, USA) was used to acquire images in the lateral decubitus position. Optic disc cube and high-definition line raster scans centered on the ONH were obtained immediately before and after draining CSF, while the patient maintained the lateral decubitus position. Measured parameters included retinal nerve fiber layer (RNFL) thickness, peripapillary retinal pigment epithelium/Bruch's membrane (RPE/BM) angulation, transverse neural canal diameter (NCD) and the highest vertical point of the internal limiting membrane from the transverse diameter (papillary height). The mean (±standard deviation) opening and closing CSF pressures were 34.3±11.8 and 11.6±3.3cmH2O, respectively. Mean RNFL thickness (pre LP: 196±105μm; post LP: 164±77μm, p=0.1) and transverse NCD (pre LP: 1985±559μm; post LP: 1590±228μm, p=2.0) decreased in all subjects, but with non-significant trends. The RPE/BM angle (mean change: 5.8±2.0degrees, p=0.003) decreased in all subjects. A decrease in papillary height was seen in three of five subjects (mean: pre LP: 976±275μm; post LP: 938±300μm, p=0.9). Our results show a measurable, objective change in the ONH after acute lowering of the lumbar CSF pressure, suggesting a direct link between the lumbar subarachnoid space and ONH regions, and its potential as a non-invasive method for monitoring intracranial pressures. PMID:26898579

  18. A single injection of intravitreal ranibizumab in the treatment of choroidal neovascularisation secondary to optic nerve head drusen in a child

    PubMed Central

    Alkin, Zeynep; Ozkaya, Abdullah; Yilmaz, Ihsan; Yazici, Ahmet Taylan

    2014-01-01

    Optic nerve head drusen are acellular, calcified deposits which may be found in buried or exposed drusen form. Choroidal neovascularisation secondary to optic nerve head drusen is rarely seen in childhood. This case report summarises the clinical and therapeutic outcomes of a 13-year-old girl with unilateral choroidal neovascularisation secondary to optic nerve head drusen. The patient was successfully treated with a single intravitreal ranibizumab injection. After a month from the injection the visual acuity increased dramatically and maintained at the same level during 9 months of follow-up time. There was no complication related to the injection. PMID:24792030

  19. Variations of the sciatic nerve anatomy and blood supply in the gluteal region: a review of the literature.

    PubMed

    Kanawati, Andrew James

    2014-11-01

    Variations of the sciatic nerve anatomy and blood supply are complex and largely not dealt with in common anatomy texts. Variations of the sciatic nerve anatomy can be divided into the height of division of its branches, relation of the branches to the piriformis muscle, and its blood supply. These variations should be well known to any surgeon operating in this anatomical region. It is unknown whether these variations increase the risk of surgical injury and consequent morbidity. This paper will review the current knowledge regarding anatomical variations of the sciatic nerve and its blood supply. PMID:24842563

  20. Changes in quantitative 3D shape features of the optic nerve head associated with age

    NASA Astrophysics Data System (ADS)

    Christopher, Mark; Tang, Li; Fingert, John H.; Scheetz, Todd E.; Abramoff, Michael D.

    2013-02-01

    Optic nerve head (ONH) structure is an important biological feature of the eye used by clinicians to diagnose and monitor progression of diseases such as glaucoma. ONH structure is commonly examined using stereo fundus imaging or optical coherence tomography. Stereo fundus imaging provides stereo views of the ONH that retain 3D information useful for characterizing structure. In order to quantify 3D ONH structure, we applied a stereo correspondence algorithm to a set of stereo fundus images. Using these quantitative 3D ONH structure measurements, eigen structures were derived using principal component analysis from stereo images of 565 subjects from the Ocular Hypertension Treatment Study (OHTS). To evaluate the usefulness of the eigen structures, we explored associations with the demographic variables age, gender, and race. Using regression analysis, the eigen structures were found to have significant (p < 0.05) associations with both age and race after Bonferroni correction. In addition, classifiers were constructed to predict the demographic variables based solely on the eigen structures. These classifiers achieved an area under receiver operating characteristic curve of 0.62 in predicting a binary age variable, 0.52 in predicting gender, and 0.67 in predicting race. The use of objective, quantitative features or eigen structures can reveal hidden relationships between ONH structure and demographics. The use of these features could similarly allow specific aspects of ONH structure to be isolated and associated with the diagnosis of glaucoma, disease progression and outcomes, and genetic factors.

  1. Visual loss and optic nerve head swelling in thiamine deficiency without prolonged dietary deficiency

    PubMed Central

    Gratton, Sean M; Lam, Byron L

    2014-01-01

    Visual loss due to optic neuropathy is a rare manifestation of thiamine deficiency. We report a case of a 39-year-old woman with a body mass index (BMI) of 29 kg/m2 who developed visual loss and bilateral optic nerve head swelling after a short, self-limited gastrointestinal illness. She was disoriented and inattentive and had absent ankle jerk reflexes, diminished sensation in both legs below the knees, and marked truncal ataxia. Magnetic resonance imaging (MRI) showed increased T2-signal in the medial thalami and mammillary bodies. The serum thiamine level was 8 nmol/L (normal 8–30). The diagnosis of thiamine deficiency was made, and the patient’s vision and neurologic symptoms improved significantly with intramuscular thiamine treatment. Thiamine deficiency can occur in the absence of an obvious predisposing factor such as alcoholism or low body weight. The clinician must be aware of the factors that govern vitamin availability and maintain a high index of suspicion to make the diagnosis in such cases. PMID:24899800

  2. Detecting abnormality in optic nerve head images using a feature extraction analysis

    PubMed Central

    Zhu, Haogang; Poostchi, Ali; Vernon, Stephen A; Crabb, David P

    2014-01-01

    Imaging and evaluation of the optic nerve head (ONH) plays an essential part in the detection and clinical management of glaucoma. The morphological characteristics of ONHs vary greatly from person to person and this variability means it is difficult to quantify them in a standardized way. We developed and evaluated a feature extraction approach using shift-invariant wavelet packet and kernel principal component analysis to quantify the shape features in ONH images acquired by scanning laser ophthalmoscopy (Heidelberg Retina Tomograph [HRT]). The methods were developed and tested on 1996 eyes from three different clinical centers. A shape abnormality score (SAS) was developed from extracted features using a Gaussian process to identify glaucomatous abnormality. SAS can be used as a diagnostic index to quantify the overall likelihood of ONH abnormality. Maps showing areas of likely abnormality within the ONH were also derived. Diagnostic performance of the technique, as estimated by ROC analysis, was significantly better than the classification tools currently used in the HRT software – the technique offers the additional advantage of working with all images and is fully automated. PMID:25071960

  3. Identification and localization of lamina cribrosa cells in the human optic nerve head.

    PubMed

    Tovar-Vidales, Tara; Wordinger, Robert J; Clark, Abbot F

    2016-06-01

    One of the central features of glaucoma is progressive cupping and excavation of the optic nerve head (ONH). Unmyelinated retinal ganglion cell (RGC) axons exit the eye through the ONH, which is supported by the lamina cribrosa (LC) consisting of plates of connective tissue with channels for bundles of RGC axons. The LC progressively remodels during glaucoma, but the cellular and molecular mechanisms responsible for this remodeling are poorly understood. Two major cell types have been isolated and cultured from the human ONH, which differ in their characteristics. Glial fibrillary acidic protein (GFAP) positive ONH astrocytes are the major cell type and are reactive in glaucoma. GFAP negative LC cells are the second major cell type isolated from the human ONH, and in contrast to ONH astrocytes, are α-smooth muscle actin (α-SMA) positive. Although a number of in vitro studies have been conducted with LC cells, to date there has been no direct evidence for these cells in situ in the human ONH. We used GFAP and α-SMA immunofluorescent staining of human eyes to clearly demonstrate the presence of not only ONH astrocytes within the human ONH, but also LC cells within the cribriform (e.g. laminar) plates/beams of the LC region. Both of these cell types likely play important roles in the homeostatic maintenance of the ONH and pathogenic changes that occur in primary open angle glaucoma (POAG). PMID:27167365

  4. In vivo optic nerve head biomechanics: performance testing of a three-dimensional tracking algorithm

    PubMed Central

    Girard, Michaël J. A.; Strouthidis, Nicholas G.; Desjardins, Adrien; Mari, Jean Martial; Ethier, C. Ross

    2013-01-01

    Measurement of optic nerve head (ONH) deformations could be useful in the clinical management of glaucoma. Here, we propose a novel three-dimensional tissue-tracking algorithm designed to be used in vivo. We carry out preliminary verification of the algorithm by testing its accuracy and its robustness. An algorithm based on digital volume correlation was developed to extract ONH tissue displacements from two optical coherence tomography (OCT) volumes of the ONH (undeformed and deformed). The algorithm was tested by applying artificial deformations to a baseline OCT scan while manipulating speckle noise, illumination and contrast enhancement. Tissue deformations determined by our algorithm were compared with the known (imposed) values. Errors in displacement magnitude, orientation and strain decreased with signal averaging and were 0.15 µm, 0.15° and 0.0019, respectively (for optimized algorithm parameters). Previous computational work suggests that these errors are acceptable to provide in vivo characterization of ONH biomechanics. Our algorithm is robust to OCT speckle noise as well as to changes in illumination conditions, and increasing signal averaging can produce better results. This algorithm has potential be used to quantify ONH three-dimensional strains in vivo, of benefit in the diagnosis and identification of risk factors in glaucoma. PMID:23883953

  5. The Role of Postoperative Radiotherapy for Large Nerve Perineural Spread of Cancer of the Head and Neck.

    PubMed

    Gorayski, Peter; Foote, Matthew; Porceddu, Sandro; Poulsen, Michael

    2016-04-01

    Large nerve perineural spread (LNPNS) is an uncommon but serious sequelae of cutaneous and salivary gland malignancies arising in the head and neck. This distinct clinical entity is caused by malignant cell spread along the course of larger (named) cranial nerves in a bidirectional pattern of spread toward the origins of the nerve in the brainstem and/or its most distal branches residing in the dermis. Untreated, LNPNS causes multiple cranial neuropathies that significantly impact on quality of life and ultimately is fatal. Curative treatment involves en bloc surgical resection of all known involved sites of gross disease followed by risk-adapted postoperative radiotherapy (PORT) to improve local control. We review the evidence for contemporary practice and outline the processes involved in the delivery of PORT using the zonal anatomical classification. PMID:27123394

  6. [The effect of in vitro X-irradiated blood transfusions on the morphostructure of immunocompetent organs and their nerve elements].

    PubMed

    Iulish, E I

    1991-01-01

    A study was made of changes that occur in the rat thymus, spleen, lymph nodes, their nerve elements, and spinal ganglia under the effect of the in vitro X-irradiated blood transfusions. Parallelism was noted in the activation of the immunocompetent organ morphostructures, the rate of reactive alterations in nerve elements, and the improvement of the immunity indices. PMID:1887004

  7. Optic nerve head perfusion in normal eyes and eyes with glaucoma using optical coherence tomography-based microangiography

    PubMed Central

    Chen, Chieh-Li; Bojikian, Karine D.; Gupta, Divakar; Wen, Joanne C.; Zhang, Qinqin; Xin, Chen; Kono, Rei; Mudumbai, Raghu C.; Johnstone, Murray A.; Chen, Philip P.

    2016-01-01

    Background To investigate the differences of perfusion in the optic nerve head (ONH) between normal and glaucomatous eyes using optical microangiography (OMAG) based optical coherence tomography (OCT) angiography technique. Methods One eye from each subject was scanned with a 68 kHz Cirrus 5000 HD-OCT-based OMAG prototype system centered at the ONH (Carl Zeiss Meditec Inc, Dublin, CA, USA). Microvascular images were generated from the OMAG dataset by detecting the differences in OCT signal between consecutive B-scans. The pre-laminar layer (preLC) was isolated by a semi-automatic segmentation program. En face OMAG images for preLC were generated using signals with highest blood flow signal intensity. ONH perfusion was quantified as flux, vessel area density, and normalized flux within the ONH. Standard t-tests were performed to analyze the ONH perfusion differences between normal and glaucomatous eyes. Linear regression models were constructed to analyze the correlation between ONH perfusion and other clinical measurements. Results Twenty normal and 21 glaucoma subjects were enrolled. Glaucomatous eyes had significantly lower ONH perfusion in preLC in all three perfusion metrics compared to normal eyes (P≤0.0003). Significant correlations between ONH perfusion and disease severity as well as structural changes were detected in glaucomatous eyes (P≤0.012). Conclusions ONH perfusion detected by OMAG showed significant differences between glaucoma and normal controls and was significantly correlated with disease severity and structural defects in glaucomatous eyes. ONH perfusion measurement using OMAG may provide useful information for detection and monitoring of glaucoma. PMID:27190764

  8. Macrophage-Induced Blood Vessels Guide Schwann Cell-Mediated Regeneration of Peripheral Nerves

    PubMed Central

    Cattin, Anne-Laure; Burden, Jemima J.; Van Emmenis, Lucie; Mackenzie, Francesca E.; Hoving, Julian J.A.; Garcia Calavia, Noelia; Guo, Yanping; McLaughlin, Maeve; Rosenberg, Laura H.; Quereda, Victor; Jamecna, Denisa; Napoli, Ilaria; Parrinello, Simona; Enver, Tariq; Ruhrberg, Christiana; Lloyd, Alison C.

    2015-01-01

    Summary The peripheral nervous system has remarkable regenerative capacities in that it can repair a fully cut nerve. This requires Schwann cells to migrate collectively to guide regrowing axons across a ‘bridge’ of new tissue, which forms to reconnect a severed nerve. Here we show that blood vessels direct the migrating cords of Schwann cells. This multicellular process is initiated by hypoxia, selectively sensed by macrophages within the bridge, which via VEGF-A secretion induce a polarized vasculature that relieves the hypoxia. Schwann cells then use the blood vessels as “tracks” to cross the bridge taking regrowing axons with them. Importantly, disrupting the organization of the newly formed blood vessels in vivo, either by inhibiting the angiogenic signal or by re-orienting them, compromises Schwann cell directionality resulting in defective nerve repair. This study provides important insights into how the choreography of multiple cell-types is required for the regeneration of an adult tissue. PMID:26279190

  9. A Modeling of Cerebral Blood Flow Changes due to Head Motion for fNIRS

    NASA Astrophysics Data System (ADS)

    Takahashi, Kosuke; Tanaka, Takayuki; Nara, Hiroyuki; Kaneko, Shun'ichi; Inoue, Masao; Shimizu, Shunji; Kojima, Satoru

    2013-04-01

    A method is proposed for measuring brain activity during exercises involving head motion by using functional near-infrared spectroscopy (fNIRS), which investigates cerebral hemodynamics. Obtaining measurements during exercise is difficult because cerebral blood flow changes due to the head motion component (HMC), in addition to neural activity. HMC is an undesirable artifact in the measurement of hemodynamic response caused by neural activity, and as such, it must be estimated and eliminated. In our experiments, cerebral blood flow and head motion were measured during repeated passive forward bending of the subjects. Head motion was measured by 3-D motion capture, and HMC was estimated by deriving a relation between head motion and cerebral blood flow, where the pitch angle was found to be suitable for estimating HMC. In this research, an assumption was made that cerebral blood flow caused by neural activity and that caused by postural change were additive, and thus HMC was eliminated by subtraction.

  10. Optic nerve head and intraocular pressure in the guinea pig eye.

    PubMed

    Ostrin, Lisa A; Wildsoet, Christine F

    2016-05-01

    The guinea pig is becoming an increasingly popular model for studying human myopia, which carries an increased risk of glaucoma. As a step towards understanding this association, this study sought to characterize the normal, developmental intraocular pressure (IOP) profiles, as well as the anatomy of the optic nerve head (ONH) and adjacent sclera of young guinea pigs. IOP was tracked in pigmented guinea pigs up to 3 months of age. One guinea pig was imaged in vivo with OCT and one with a fundus camera. The eyes of pigmented and albino guinea pigs (ages 2 months) were enucleated and sections from the posterior segment, including the ONH and surrounding sclera, processed for histological analyses - either hematoxylin and eosin (H&E) staining of paraffin embedded, sectioned tissue (n = 1), or cryostat sectioned tissue, processed for immunohistochemistry (n = 3), using primary antibodies against collagen types I-V, elastin, fibronectin and glial fibrillary acidic protein (GFAP). Transmission and scanning electron microscopy (TEM, SEM) studies of ONHs were also undertaken (n = 2 & 5 respectively). Mean IOPs ranged from 17.33 to 22.7 mmHg, increasing slightly across the age range studied, and the IOPs of individual animals also exhibited diurnal variations, peaking in the early morning (mean of 25.8, mmHg, ∼9 am), and decreasing across the day. H&E-stained sections showed retinal ganglion cell axons organized into fascicles in the prelaminar and laminar region of the ONHs, with immunostained sections revealing collagen types I, III, IV and V, as well as elastin, GFAP and fibronectin in the ONHs. SEM revealed a well-defined lamina cribrosa (LC), with radially-oriented collagen beams. TEM revealed collagen fibrils surrounding non-myelinated nerve fiber bundles in the LC region, with myelination and decreased collagen posterior to the LC. The adjacent sclera comprised mainly crimped collagen fibers in a crisscross arrangement. Both the sclera and LC were

  11. Optical coherence tomography angiography of optic nerve head and parafovea in multiple sclerosis

    PubMed Central

    Wang, Xiaogang; Jia, Yali; Spain, Rebecca; Potsaid, Benjamin; Liu, Jonathan J; Baumann, Bernhard; Hornegger, Joachim; Fujimoto, James G; Wu, Qiang; Huang, David

    2015-01-01

    Aims To investigate swept-source optical coherence tomography (OCT) angiography in the optic nerve head (ONH) and parafoveal regions in patients with multiple sclerosis (MS). Methods Fifty-two MS eyes and 21 healthy control (HC) eyes were included. There were two MS subgroups: 38 MS eyes without an optic neuritis (ON) history (MS −ON), and 14 MS eyes with an ON history (MS +ON). The OCT images were captured by high-speed 1050 nm swept-source OCT. The ONH flow index (FI) and parafoveal FI were quantified from OCT angiograms. Results The mean ONH FI was 0.160±0.010 for the HC group, 0.156±0.017 for the MS−ON group, and 0.140±0.020 for the MS+ON group. The ONH FI of the MS+ON group was reduced by 12.5% compared to HC eyes (p=0.004). A higher percentage of MS+ON eyes had abnormal ONH FI compared to HC patients (43% vs 5%, p=0.01). Mean parafoveal FIs were 0.126±0.007, 0.127±0.010, and 0.129±0.005 for the HC, MS−ON, and MS +ON groups, respectively, and did not differ significantly among them. The coefficient of variation (CV) of intravisit repeatability and intervisit reproducibility were 1.03% and 4.53% for ONH FI, and 1.65% and 3.55% for parafoveal FI. Conclusions Based on OCT angiography, the FI measurement is feasible, highly repeatable and reproducible, and it is suitable for clinical measurement of ONH and parafoveal perfusion. The ONH FI may be useful in detecting damage from ON and quantifying its severity. PMID:24831719

  12. Human umbilical cord blood-derived stem cells and brain-derived neurotrophic factor protect injured optic nerve: viscoelasticity characterization.

    PubMed

    Lv, Xue-Man; Liu, Yan; Wu, Fei; Yuan, Yi; Luo, Min

    2016-04-01

    The optic nerve is a viscoelastic solid-like biomaterial. Its normal stress relaxation and creep properties enable the nerve to resist constant strain and protect it from injury. We hypothesized that stress relaxation and creep properties of the optic nerve change after injury. More-over, human brain-derived neurotrophic factor or umbilical cord blood-derived stem cells may restore these changes to normal. To validate this hypothesis, a rabbit model of optic nerve injury was established using a clamp approach. At 7 days after injury, the vitreous body re-ceived a one-time injection of 50 μg human brain-derived neurotrophic factor or 1 × 10(6) human umbilical cord blood-derived stem cells. At 30 days after injury, stress relaxation and creep properties of the optic nerve that received treatment had recovered greatly, with patho-logical changes in the injured optic nerve also noticeably improved. These results suggest that human brain-derived neurotrophic factor or umbilical cord blood-derived stem cell intervention promotes viscoelasticity recovery of injured optic nerves, and thereby contributes to nerve recovery. PMID:27212930

  13. Human umbilical cord blood-derived stem cells and brain-derived neurotrophic factor protect injured optic nerve: viscoelasticity characterization

    PubMed Central

    Lv, Xue-man; Liu, Yan; Wu, Fei; Yuan, Yi; Luo, Min

    2016-01-01

    The optic nerve is a viscoelastic solid-like biomaterial. Its normal stress relaxation and creep properties enable the nerve to resist constant strain and protect it from injury. We hypothesized that stress relaxation and creep properties of the optic nerve change after injury. More-over, human brain-derived neurotrophic factor or umbilical cord blood-derived stem cells may restore these changes to normal. To validate this hypothesis, a rabbit model of optic nerve injury was established using a clamp approach. At 7 days after injury, the vitreous body re-ceived a one-time injection of 50 μg human brain-derived neurotrophic factor or 1 × 106 human umbilical cord blood-derived stem cells. At 30 days after injury, stress relaxation and creep properties of the optic nerve that received treatment had recovered greatly, with patho-logical changes in the injured optic nerve also noticeably improved. These results suggest that human brain-derived neurotrophic factor or umbilical cord blood-derived stem cell intervention promotes viscoelasticity recovery of injured optic nerves, and thereby contributes to nerve recovery. PMID:27212930

  14. Characterizing biological variability in livestock blood cholinesterase activity for biomonitoring organophosphate nerve agent exposure.

    PubMed

    Halbrook, R S; Shugart, L R; Watson, A P; Munro, N B; Linnabary, R D

    1992-09-01

    A biomonitoring protocol, using blood cholinesterase (ChE) activity in livestock as a monitor of potential organophosphate nerve agent exposure during the planned destruction of US unitary chemical warfare agent stockpiles, is described. The experimental design included analysis of blood ChE activity in individual healthy sheep, horses, and dairy and beef cattle during a 10- to 12-month period. Castrated and sexually intact males, pregnant and lactating females, and adult and immature animals were examined through at least one reproductive cycle. The same animals were used throughout the period of observation and were not exposed to ChE-inhibiting organophosphate or carbamate compounds. A framework for an effective biomonitoring protocol within a monitoring area includes establishing individual baseline blood ChE activity for a sentinel group of 6 animals on the bases of blood samples collected over a 6-month period, monthly collection of blood samples for ChE-activity determination during monitoring, and selection of adult animals as sentinels. Exposure to ChE-inhibiting compounds would be suspected when all blood ChE activity of all animals within the sentinel group are decreased greater than 20% from their own baseline value. Sentinel species selection is primarily a logistical and operational concern; however, sheep appear to be the species of choice because within-individual baseline ChE activity and among age and gender group ChE activity in sheep had the least variability, compared with data from other species. This protocol provides an effective and efficient means for detecting abnormal depressions in blood ChE activity in livestock and can serve as a valuable indicator of the extent of actual plume movement and/or deposition in the event of organophosphate nerve agent release. PMID:1399773

  15. Characterizing biological variability in livestock blood cholinesterase activity for biomonitoring organophosphate nerve agent exposure

    SciTech Connect

    Halbrook, R.S.; Shugart, L.R.; Watson, A.P.; Munro, N.B.; Linnabary, R.D. )

    1992-09-01

    A biomonitoring protocol, using blood cholinesterase (ChE) activity in livestock as a monitor of potential organophosphate nerve agent exposure during the planned destruction of US unitary chemical warfare agent stockpiles, is described. The experimental design included analysis of blood ChE activity in individual healthy sheep, horses, and dairy and beef cattle during a 10- to 12-month period. Castrated and sexually intact males, pregnant and lactating females, and adult and immature animals were examined through at least one reproductive cycle. The same animals were used throughout the period of observation and were not exposed to ChE-inhibiting organophosphate or carbamate compounds. A framework for an effective biomonitoring protocol within a monitoring area includes establishing individual baseline blood ChE activity for a sentinel group of 6 animals on the bases of blood samples collected over a 6-month period, monthly collection of blood samples for ChE-activity determination during monitoring, and selection of adult animals as sentinels. Exposure to ChE-inhibiting compounds would be suspected when all blood ChE activity of all animals within the sentinel group are decreased greater than 20% from their own baseline value. Sentinel species selection is primarily a logistical and operational concern; however, sheep appear to be the species of choice because within-individual baseline ChE activity and among age and gender group ChE activity in sheep had the least variability, compared with data from other species. This protocol provides an effective and efficient means for detecting abnormal depressions in blood ChE activity in livestock and can serve as a valuable indicator of the extent of actual plume movement and/or deposition in the event of organophosphate nerve agent release.

  16. On the vagal cardiac nerves, with special reference to the early evolution of the head-trunk interface.

    PubMed

    Higashiyama, Hiroki; Hirasawa, Tatsuya; Oisi, Yasuhiro; Sugahara, Fumiaki; Hyodo, Susumu; Kanai, Yoshiakira; Kuratani, Shigeru

    2016-09-01

    The vagus nerve, or the tenth cranial nerve, innervates the heart in addition to other visceral organs, including the posterior visceral arches. In amniotes, the anterior and posterior cardiac branches arise from the branchial and intestinal portions of the vagus nerve to innervate the arterial and venous poles of the heart, respectively. The evolution of this innervation pattern has yet to be elucidated, due mainly to the lack of morphological data on the vagus in basal vertebrates. To investigate this topic, we observed the vagus nerves of the lamprey (Lethenteron japonicum), elephant shark (Callorhinchus milii), and mouse (Mus musculus), focusing on the embryonic patterns of the vagal branches in the venous pole. In the lamprey, no vagus branch was found in the venous pole throughout development, whereas the arterial pole was innervated by a branch from the branchial portion. In contrast, the vagus innervated the arterial and venous poles in the mouse and elephant shark. Based on the morphological patterns of these branches, the venous vagal branches of the mouse and elephant shark appear to belong to the intestinal part of the vagus, implying that the cardiac nerve pattern is conserved among crown gnathostomes. Furthermore, we found a topographical shift of the structures adjacent to the venous pole (i.e., the hypoglossal nerve and pronephros) between the extant gnathostomes and lamprey. Phylogenetically, the lamprey morphology is likely to be the ancestral condition for vertebrates, suggesting that the evolution of the venous branch occurred early in the gnathostome lineage, in parallel with the remodeling of the head-trunk interfacial domain during the acquisition of the neck. J. Morphol. 277:1146-1158, 2016. © 2016 Wiley Periodicals, Inc. PMID:27216138

  17. A lab-on-a-chip for detection of nerve agent sarin in blood.

    PubMed

    Tan, Hsih Yin; Loke, Weng Keong; Tan, Yong Teng; Nguyen, Nam-Trung

    2008-06-01

    Sarin (C(4)H(10)FO(2)P,O-isopropyl methylphosphonofluoridate) is a colourless, odourless and highly toxic phosphonate that acts as a cholinesterase inhibitor and disrupts neuromuscular transmission. Sarin and related phosphonates are chemical warfare agents, and there is a possibility of their application in a military or terrorist attack. This paper reports a lab-on-a-chip device for detecting a trace amount of sarin in a small volume of blood. The device should allow early detection of sarin exposure during medical triage to differentiate between those requiring medical treatment from mass psychogenic illness cases. The device is based on continuous-flow microfluidics with sequential stages for lysis of whole blood, regeneration of free nerve agent from its complex with blood cholinesterase, protein precipitation, filtration, enzyme-assisted reaction and optical detection. Whole blood was first mixed with a nerve gas regeneration agent, followed by a protein precipitation step. Subsequently, the lysed product was filtered on the chip in two steps to remove particulates and fluoride ions. The filtered blood sample was then tested for trace levels of regenerated sarin using immobilised cholinesterase on the chip. Activity of immobilised cholinesterase was monitored by the enzyme-assisted reaction of a substrate and reaction of the end-product with a chromophore. Resultant changes in chromophore-induced absorbance were recorded on the chip using a Z-shaped optical window. Loss of enzyme activity obtained prior and after passage of the treated blood sample, as shown by a decrease in recorded absorbance values, indicates the presence of either free or regenerated sarin in the blood sample. The device was fabricated in PMMA (polymethylmethacrylate) using CO(2)-laser micromachining. This paper reports the testing results of the different stages, as well as the whole device with all stages in the required assay sequence. The results demonstrate the potential use of a

  18. Dose-dependent variations in blood flow evaluation of canine nerve, nerve graft, tendon, and ligament tissue by the radiolabeled-microsphere technique

    SciTech Connect

    Riggi, K.; Wood, M.B.; Ilstrup, D.M. )

    1990-11-01

    This study evaluates the dose-dependent accuracy of the radionuclide-labeled microsphere technique for blood flow evaluation in nerve, tendon, and ligament. In eight dogs, blood flows were determined for nerve, nerve graft, tendon, and ligament tissue by simultaneous injection of high- and low-dose microspheres with different radiolabels. The results demonstrated no significant differences in blood flow as measured from the small number of microspheres (less than 400) and the high number (more than 400) for nerve and tendon tissue. For nerve tissue, microsphere counts of 50 to 100, 100 to 200, 200 to 300, and more than 300 produced mean percentage errors of 12.74% (n = 5, SEM = 4.52), 5.45% (n = 13, SEM = 1.22), 10.22% (n = 6, SEM = 4.37), and 17.08% (n = 12, SEM = 3.30), respectively. For tendon tissue, the same microsphere subdivisions had mean percentage errors of 7.47% (n = 4, SEM = 2.66), 3.63% (n = 6, SEM = 1.34), 15.54% (n = 4, SEM = 4.43), and 12.91% (n = 1), respectively. For ligament tissue, percentage errors were consistently higher; microsphere counts of 30 to 100, 100 to 200, and 200 to 300 produced mean errors of 20.14% (n = 4, SEM = 6.38), 18.66% (n = 4, SEM = 6.24), and 25.78% (n = 2, SEM = 1.97), respectively. Although there was no direct relationship between percentage error and number of microspheres retrieved, we suggest that microsphere counts in the range of 100 to 200 should be considered acceptable for nerve and tendon in the canine. Ligament tissue seems to be less well suited to the microsphere technique; however, further study is warranted.

  19. Responses of bone and joint blood vessels in cats and rabbits to electrical stimulation of nerves supplying the knee.

    PubMed Central

    Ferrell, W R; Khoshbaten, A; Angerson, W J

    1990-01-01

    1. Experiments were performed to assess the extent to which knee joint blood flow in cats and rabbits is affected by electrical stimulation of the nerve supply to the knee. 2. Absolute changes in blood flow were measured using the radiolabelled microsphere (approximately 15 microns) technique whilst relative changes in blood flow were assessed using laser Doppler flowmetry. 3. Despite deep general anaesthesia, sympathetic nerve fibres innervating cat knee joint blood vessels showed marked 'tone'. 4. Blood flow to the joint capsule (synovium and overlying fibrous and areolar tissues) was substantially reduced (by approximately 90% in the cat and approximately 45% in the rabbit) during electrical stimulation of the articular nerve supply. 5. The percentage change in the laser Doppler flowmeter signal did not differ significantly from the percentage change in blood flow measured by microsphere technique. 6. Blood vessels in the cancellous bone of the distal femur (condyles) and proximal tibia (plateau) appear to be innervated by vasoconstrictor fibres which reach their effectors via the articular nerves. However, the cortical bone and red marrow of the diaphysis of the femur do not receive such innervation. 7. The potency of the vasoconstrictor influences acting on joint blood vessels could be of relevance in the pathogenesis of inflammatory joint diseases. PMID:2100317

  20. Blood pressure control with selective vagal nerve stimulation and minimal side effects

    NASA Astrophysics Data System (ADS)

    Plachta, Dennis T. T.; Gierthmuehlen, Mortimer; Cota, Oscar; Espinosa, Nayeli; Boeser, Fabian; Herrera, Taliana C.; Stieglitz, Thomas; Zentner, Joseph

    2014-06-01

    Objective. Hypertension is the largest threat to patient health and a burden to health care systems. Despite various options, 30% of patients do not respond sufficiently to medical treatment. Mechanoreceptors in the aortic arch relay blood pressure (BP) levels through vagal nerve (VN) fibers to the brainstem and trigger the baroreflex, lowering the BP. Selective electrical stimulation of these nerve fibers reduced BP in rats. However, there is no technique described to localize and stimulate these fibers inside the VN without inadvertent stimulation of non-baroreceptive fibers causing side effects like bradycardia and bradypnea. Approach. We present a novel method for selective VN stimulation to reduce BP without the aforementioned side effects. Baroreceptor compound activity of rat VN (n = 5) was localized using a multichannel cuff electrode, true tripolar recording and a coherent averaging algorithm triggered by BP or electrocardiogram. Main results. Tripolar stimulation over electrodes near the barofibers reduced the BP without triggering significant bradycardia and bradypnea. The BP drop was adjusted to 60% of the initial value by varying the stimulation pulse width and duration, and lasted up to five times longer than the stimulation. Significance. The presented method is robust to impedance changes, independent of the electrode's relative position, does not compromise the nerve and can run on implantable, ultra-low power signal processors.

  1. The Relationship Between Retinal Nerve Fiber Layer Thickness and Optic Nerve Head Neuroretinal Rim Tissue in Glaucoma

    PubMed Central

    Patel, Nimesh B.; Sullivan-Mee, Michael; Harwerth, Ronald S.

    2014-01-01

    Purpose. The purpose of this study was to determine the relationship between optical coherence tomography (OCT) measures of retinal nerve fiber layer (RNFL) and neuroretinal rim (NRR) in a nonhuman primate experimental glaucoma model, and in a population of clinical patients. Methods. For nonhuman primates, normative data were collected from 44 healthy monkeys, and nine animals with unilateral experimental glaucoma that were followed longitudinally. Cross-sectional human subjects data were collected from 89 healthy, 74 glaucoma suspects, and 104 glaucoma patients. Individualized transverse scaling for OCT scans was calculated using a schematic eye that incorporated optical ocular biometry. Custom algorithms were used to quantify RNFL thickness with and without vessels removed, scaled minimum rim width (sMRW), and neural rim volume (NRV). Results. For the experimental glaucoma group, NRR parameters showed the first changes with increased cumulative IOP. The data for both NRR and RNFL measures were best fit by an exponential rise model (NRV, R2 = 0.79, P < 0.01, sMRW, R2 = 0.74, P < 0.01). The major retinal vascular thickness contribution to the RNFL decreased (0.03 μm/μm, P < 0.01) with RNFL loss, but the percent vascular contribution increased (−0.1%/μm, P < 0.01) with disease progression. Overall, the findings for the cross-sectional human data were similar to those of the experimental model. Conclusions. The findings illustrate a nonlinear relationship between NRR and RNFL measures and provide support for the use of multiple OCT scaled morphological measures for the diagnosis and management of primary open angle glaucoma in humans. PMID:25249610

  2. An immortalized human blood-nerve barrier endothelial cell line for in vitro permeability studies

    PubMed Central

    Yosef, Nejla; Ubogu, Eroboghene E.

    2012-01-01

    Solute and macromolecular transport studies may elucidate nutritional requirements and drug effects in healthy and diseased peripheral nerves. Endoneurial endothelial cells are specialized microvascular cells that form the restrictive blood-nerve barrier (BNB). Primary human endoneurial endothelial cells (pHEndECs) are difficult to isolate, limiting their widespread availability for biomedical research. We developed a simian virus-40 large T-antigen (SV40-LTA) immortalized human BNB cell line via stable transfection of low passage pHEndECs and observed continuous growth in culture for >45 population doublings. As observed with pHEndECs, the immortalized BNB endothelial cells were Ulex Europaeus agglutinin-1 (UEA-1)-positive and endocytosed low density lipoprotein, but lost von Willebrand factor (vWF) expression. Glucose transporter-1 (GLUT-1), P-glycoprotein (P-gp), γ-glutamyl transpeptidase (γ-GT), large neutral amino acid transporter-1 (LAT-1), creatine transporter (CRT) and monocarboxylate transporter-1 (MCT-1) mRNA expression were retained at all passages with loss of alkaline phosphatase (AP) expression after passages 16-20. Compared with an SV40-LTA immortalized human blood-brain barrier (BBB) endothelial cell line, there was increased γ-GT protein expression, equivalent expression of organic anion transporting polypeptide-C (OATP-C), organic anion transporter 3 (OAT-3), MCT-1 and LAT-1, and reduced expression of AP, CRT and P-gp by the BNB cell line at passage 20. Further studies demonstrated lower transendothelial electrical resistance (TEER: ~181 Ω.cm2 vs. 191 Ω.cm2), equivalent permeability to fluoresceinated sodium (4.84% vs. 4.39%) and lower permeability to fluoresceinated high molecular weight (70 kDa) dextran (0.39% vs. 0.52%) by the BNB cell line. This cell line retained essential molecular and biophysical properties suitable for in vitro peripheral nerve permeability studies. PMID:23104242

  3. Femoral head blood flow in long-term steroid therapy: study of rabbit model

    SciTech Connect

    Wang, G.J.; Hubbard, S.L.; Reger, S.I.; Miller, E.D.; Stamp, W.G.

    1983-12-01

    Using a rabbit model, previous studies showed steroid-induced hyperlipidemia with subsequent fatty embolization of the subchondral arteries and hypertrophy of the marrow fat cells, followed by elevation of femoral head pressure from the normal level of 25 cm to nearly 60 cm H2O after eight weeks of treatment. This has led us to believe that pressure changes lead to decreased blood flow in the femoral head. In our study of 22 New Zealand white adult rabbits, weighing an average of 4.0 kg, 14 received a weekly dose of 12.45 mg of methylprednisolone (Depo-Medrol), and eight served as control. Femoral head blood flow was established using the radioactive microsphere technique. Control and cortisone-treated rabbits had femoral head blood flow measured 6, 8 and 10 weeks after treatment. The average blood flow in the control femoral heads averaged 0.2039 +/- 0.076 ml/min/gm, with no difference in the left side and the right side. In the treated group, the average blood flow at ten weeks was 0.162 +/- 0.039 ml/min/gm on the right and 0.164 +/- 0.037 ml/min/gm on the left, which was significantly different. This is parallel to unpredictable clinical findings in human beings.

  4. Femoral head blood flow in long-term steroid therapy: study of rabbit model.

    PubMed

    Wang, G J; Hubbard, S L; Reger, S I; Miller, E D; Stamp, W G

    1983-12-01

    Using a rabbit model, previous studies showed steroid-induced hyperlipidemia with subsequent fatty embolization of the subchondral arteries and hypertrophy of the marrow fat cells, followed by elevation of femoral head pressure from the normal level of 25 cm to nearly 60 cm H2O after eight weeks of treatment. This has led us to believe that pressure changes lead to decreased blood flow in the femoral head. In our study of 22 New Zealand white adult rabbits, weighing an average of 4.0 kg, 14 received a weekly dose of 12.45 mg of methylprednisolone (Depo-Medrol), and eight served as control. Femoral head blood flow was established using the radioactive microsphere technique. Control and cortisone-treated rabbits had femoral head blood flow measured 6, 8 and 10 weeks after treatment. The average blood flow in the control femoral heads averaged 0.2039 +/- 0.076 ml/min/gm, with no difference in the left side and the right side. In the treated group, the average blood flow at ten weeks was 0.162 +/- 0.039 ml/min/gm on the right and 0.164 +/- 0.037 ml/min/gm on the left, which was significantly different. This is parallel to unpredictable clinical findings in human beings. PMID:6648615

  5. Comparison of CCD-equipped laser speckle flowgraphy with hydrogen gas clearance method in the measurement of optic nerve head microcirculation in rabbits.

    PubMed

    Takahashi, Hiroaki; Sugiyama, Tetsuya; Tokushige, Hideki; Maeno, Takatoshi; Nakazawa, Toru; Ikeda, Tsunehiko; Araie, Makoto

    2013-03-01

    The aim of this study was to verify the correlation between mean blur rate (MBR) obtained with CCD-equipped laser speckle flowgraphy (LSFG) and capillary blood flow (CBF) obtained by the hydrogen gas clearance method in rabbit optic nerve head (ONH). Using Japanese white rabbits under systemic anesthesia, a hydrogen electrode was inserted an area of the ONH free from superficial capillaries. MBR was measured with LSFG near the hydrogen electrode. CBF and MBR were measured in the range of 32.4-83.5 mL/min/100 g and 3.5-6.0, respectively. MBR and CBF were significantly correlated (r = 0.73, P < 0.01, n = 14). After inhalation of carbon dioxide (CO(2)) or intravenous administration of endothelin-1 (ET-1), MBR and CBF were changed in the relative range of 0.74-1.27 and 0.76-1.35, respectively. The relative changes in MBR and CBF induced by CO(2) and ET-1 were also significantly correlated (r = 0.67, P < 0.01). The current results suggest that MBR may correlate with CBF and also change with CBF, as an index of blood flow in the ONH, linearly. PMID:23262066

  6. Human umbilical cord blood stem cells and brain-derived neurotrophic factor for optic nerve injury: a biomechanical evaluation.

    PubMed

    Zhang, Zhong-Jun; Li, Ya-Jun; Liu, Xiao-Guang; Huang, Feng-Xiao; Liu, Tie-Jun; Jiang, Dong-Mei; Lv, Xue-Man; Luo, Min

    2015-07-01

    Treatment for optic nerve injury by brain-derived neurotrophic factor or the transplantation of human umbilical cord blood stem cells has gained progress, but analysis by biomechanical indicators is rare. Rabbit models of optic nerve injury were established by a clamp. At 7 days after injury, the vitreous body received a one-time injection of 50 μg brain-derived neurotrophic factor or 1 × 10(6) human umbilical cord blood stem cells. After 30 days, the maximum load, maximum stress, maximum strain, elastic limit load, elastic limit stress, and elastic limit strain had clearly improved in rabbit models of optical nerve injury after treatment with brain-derived neurotrophic factor or human umbilical cord blood stem cells. The damage to the ultrastructure of the optic nerve had also been reduced. These findings suggest that human umbilical cord blood stem cells and brain-derived neurotrophic factor effectively repair the injured optical nerve, improve biomechanical properties, and contribute to the recovery after injury. PMID:26330839

  7. Effect of Photorefractive Keratectomy on Optic Nerve Head Topography and Retinal Nerve Fiber Layer Thickness Measured by Heidelberg Retina Tomograph 3

    PubMed Central

    Nilforushan, Naveed; Azadi, Pejvak; Soudi, Reza; Shaheen, Yahya; Sheibani, Kourosh

    2016-01-01

    Purpose: To determine whether photorefractive keratectomy (PRK) has a significant effect on optic nerve head (ONH) parameters and peripapillary retinal nerve fiber layer (RNFL) thickness measured by the Heidelberg Retina Tomograph 3 (Heidelberg Engineering GmbH, Heidelberg, Germany) in eyes with low to moderate myopia. Methods: This prospective, interventional case series, includes 43 consecutive myopic eyes which were assessed on the day of PRK and 3 months postoperatively using the HRT3. Among the stereometric parameters, we compared disc area, linear cup disc ratio, cup shape measure, global rim area, global rim volume, RNFL height variation contour and mean RNFL thickness; out of the Glaucoma Probability Score (GPS) we assessed changes in global value, rim steepness temporal/superior, and temporal/inferior, as well as cup size and cup depth before and after PRK. Results: Mean refractive error before and after PRK were −3.24 ± 1.31 and −0.20 ± 0.42 diopters, respectively. No significant change occurred in disc area, linear cup disc ratio, cup shape measure, rim area and rim volume among the stereometric parameters; and in rim steepness temporal/superior and rim steepness temporal/inferior in the GPS before and after PRK using the default average keratometry. However, RNFL height variation contour, mean RNFL thickness, and cup size and depth were significantly altered after PRK (P < 0.05). Conclusion: PRK can affect some HRT3 parameters. Although the most important stereometric parameters for differentiating normal, suspect or glaucomatous patients such as rim and cup measurements in stereometric parameters were not changed. PMID:27413492

  8. Significant correlations between optic nerve head microcirculation and visual field defects and nerve fiber layer loss in glaucoma patients with myopic glaucomatous disk

    PubMed Central

    Yokoyama, Yu; Aizawa, Naoko; Chiba, Naoki; Omodaka, Kazuko; Nakamura, Masahiko; Otomo, Takaaki; Yokokura, Shunji; Fuse, Nobuo; Nakazawa, Toru

    2011-01-01

    Background Eyes with glaucoma are characterized by optic neuropathy with visual field defects in the areas corresponding to the optic disk damage. The exact cause for the glaucomatous optic neuropathy has not been determined. Myopia has been shown to be a risk factor for glaucoma. The purpose of this study was to determine whether a significant correlation existed between the microcirculation of the optic disk and the visual field defects and the retinal nerve fiber layer thickness (RNFLT) in glaucoma patients with myopic optic disks. Methods Sixty eyes of 60 patients with myopic disks were studied; 36 eyes with glaucoma (men:women = 19:17) and 24 eyes with no ocular diseases (men:women = 14:10). The mean deviation (MD) determined by the Humphrey field analyzer, and the peripapillary RNFLT determined by the Stratus-OCT were compared between the two groups. The ocular circulation was determined by laser speckle flowgraphy (LSFG), and the mean blur rate (MBR) was compared between the two groups. The correlations between the RNFLT and MBR of the corresponding areas of the optic disk and between MD and MBR of the optic disk in the glaucoma group were determined by simple regression analyses. Results The average MBR for the entire optic disk was significantly lower in the glaucoma group than that in the control group. The differences of the MBR for the tissue in the superior, inferior, and temporal quadrants of the optic disk between the two groups were significant. The MBR for the entire optic disk was significantly correlated with the MD (r = 0.58, P = 0.0002) and the average RNFLT (r = 0.53, P = 0.0008). The tissue MBR of the optic disk was significantly correlated with the RNFLT in the superior, inferior, and temporal quadrants. Conclusions Our study suggests that there is a causal relationship between the thinner RNFLT that led to the MD and reduction in the microcirculation in the optic nerve head. PMID:22205831

  9. Renal nerves dynamically regulate renal blood flow in conscious, healthy rabbits.

    PubMed

    Schiller, Alicia M; Pellegrino, Peter R; Zucker, Irving H

    2016-01-15

    Despite significant clinical interest in renal denervation as a therapy, the role of the renal nerves in the physiological regulation of renal blood flow (RBF) remains debated. We hypothesized that the renal nerves physiologically regulate beat-to-beat RBF variability (RBFV). This was tested in chronically instrumented, healthy rabbits that underwent either bilateral surgical renal denervation (DDNx) or a sham denervation procedure (INV). Artifact-free segments of RBF and arterial pressure (AP) from calmly resting, conscious rabbits were used to extract RBFV and AP variability for time-domain, frequency-domain, and nonlinear analysis. Whereas steady-state measures of RBF, AP, and heart rate did not statistically differ between groups, DDNx rabbits had greater RBFV than INV rabbits. AP-RBF transfer function analysis showed greater admittance gain in DDNx rabbits than in INV rabbits, particularly in the low-frequency (LF) range where systemic sympathetic vasomotion gives rise to AP oscillations. In the LF range, INV rabbits exhibited a negative AP-RBF phase shift and low coherence, consistent with the presence of an active control system. Neither of these features were present in the LF range of DDNx rabbits, which showed no phase shift and high coherence, consistent with a passive, Ohm's law pressure-flow relationship. Renal denervation did not significantly affect nonlinear RBFV measures of chaos, self-affinity, or complexity, nor did it significantly affect glomerular filtration rate or extracellular fluid volume. Cumulatively, these data suggest that the renal nerves mediate LF renal sympathetic vasomotion, which buffers RBF from LF AP oscillations in conscious, healthy rabbits. PMID:26538235

  10. Prostaglandins and nitric oxide in regional kidney blood flow responses to renal nerve stimulation.

    PubMed

    Rajapakse, Niwanthi W; Flower, Rebecca L; Eppel, Gabriela A; Denton, Kate M; Malpas, Simon C; Evans, Roger G

    2004-11-01

    We examined the roles of cyclooxygenase products and of interactions between the cyclooxygenase and nitric oxide systems in the mechanisms underlying the relative insensitivity of medullary perfusion to renal nerve stimulation (RNS) in anaesthetized rabbits. To this end we examined the effects of ibuprofen and N(G)-nitro-L: -arginine (L-NNA), both alone and in combination, on the responses of regional kidney perfusion to RNS. Under control conditions, RNS produced frequency-dependent reductions in total renal blood flow (RBF; -82+/-3% at 6 Hz), cortical laser-Doppler flux (CLDF; -84+/-4% at 6 Hz) and, to a lesser extent, medullary laser-Doppler flux (MLDF; -46+/-7% at 6 Hz). Ibuprofen did not affect these responses significantly, suggesting that cyclooxygenase products have little net role in modulating renal vascular responses to RNS. L-NNA enhanced RBF (P=0.002), CLDF (P=0.03) and MLDF (P=0.03) responses to RNS. As we have shown previously, this effect of L-NNA was particularly prominent for MLDF at RNS frequencies < or = 1.5 Hz. Subsequent administration of ibuprofen, in L-NNA-pretreated rabbits, did not affect responses to RNS significantly. We conclude that counter-regulatory actions of NO, but not of prostaglandins, partly underlie the relative insensitivity of medullary perfusion to renal nerve activation. PMID:15290303

  11. Blood-Sparing Techniques in Head and Neck Surgery.

    PubMed

    Rabinowitz, Mindy R; Cognetti, David M; Nyquist, Gurston G

    2016-06-01

    Given the risks and potential complications of allogenic blood transfusion (ABT), as well as the expanding population of patients for whom ABT may not be an option, it is important for the treating physician, anesthesiologist, and surgeon to be well-versed in various alternatives. A good grasp of the concepts discussed in this article will help to customize a treatment plan that is specific to each patient's underlying disease and personal preferences without compromising appropriate medical care. PMID:27267010

  12. Imaging blood vessels of the head and neck.

    PubMed Central

    Sellar, R J

    1995-01-01

    ATHEROSCLEROTIC DISEASE: Patients with transient ischaemic attacks or a non-disabling stroke who are surgical candidates should be screened with Doppler ultrasound, or MRA/CT, or both. The choice will depend on local expertise and availability. If DUS is used it is recommended that the equipment is regularly calibrated and a prospective audit of results, particularly of those patients that go on to angiography, is maintained locally. Those patients found to have the DUS equivalent of a 50% stenosis should have angiography only if surgical or balloon angioplasty treatment is contemplated. Angiography should be performed with meticulous technique to minimise risks. ANEURYSM AND ARTERIOVENOUS MALFORMATIONS: Angiography remains the investigation of choice for patients with subarachnoid haemorrhage. Magnetic resonance angiography and CT can demonstrate the larger aneurysm but because even small aneurysms can rupture with devastating effects, these techniques are not the examination of first choice. Angiography is also the only technique that adequately defines the neck of an aneurysm. This information is becoming increasingly important in management decisions-for instance, whether to clip or use a coil. Likewise angiography is the only technique to fully define the vascular anatomy of arteriovenous malformations although the size of the nidus can be monitored by MRA and this is a useful method of follow up after stereotactic radiosurgery, embolisation, or surgery. There are specific uses for MRA such as in patients presenting with a painful 3rd nerve palsy and as a screening test for those patients with a strong family history of aneurysms. VASCULITIS, FIBROMUSCULAR HYPERPLASIA, AND DISSECTION: These rare arterial diseases are best detected by angiography, although there are increasing reports of successful diagnosis by MRA. There are traps for the many unwary and MRA does not give an anatomical depiction of the arteries but a flow map. Slow flow may lead to signal loss

  13. Effects of adenosine and adenosine A2A receptor agonist on motor nerve conduction velocity and nerve blood flow in experimental diabetic neuropathy.

    PubMed

    Kumar, Sokindra; Arun, K H S; Kaul, Chaman L; Sharma, Shyam S

    2005-01-01

    This study examined the effects of chronic administration of adenosine and CGS 21680 hydrochloride (adenosine A(2A) receptor agonist) on motor nerve conduction velocity (MNCV), nerve blood flow (NBF) and histology of sciatic nerve in animal model of diabetic neuropathy. Adenosinergic agents were administered for 2 weeks after 6 weeks of streptozotocin-induced (50 mg/kg i.p.) diabetes in male Sprague-Dawley rats. Significant reduction in sciatic MNCV and NBF were observed after 8 weeks in diabetic animals in comparison with control (non diabetic) rats. Adenosine (10 mg/kg, i.p.) significantly improved sciatic MNCV and NBF in diabetic rats. The protective effect of adenosine on MNCV and NBF was completely reversed by theophylline (50 mg/kg, i.p.), a non-selective adenosine receptor antagonist, suggesting that the adenosine effect was mediated via adenosinergic receptors. CGS 21680 (0.1 mg/kg, i.p.) significantly improved NBF; however, MNCV was not significantly improved in diabetic rats. At a dose of 1 mg/kg, neither MNCV nor NBF was improved by CGS 21680 in diabetic rats. ZM 241385 (adenosine A(2A) receptor antagonist) prevented the effect of CGS 21680 (0.1 mg/kg, i.p.). Histological changes observed in sciatic nerve were partially improved by the adenosinergic agents in diabetic rats. Results of the present study, suggest the potential of adenosinergic agents in the therapy of diabetic neuropathy. PMID:15829161

  14. Cerebral blood velocity and other cardiovascular responses to 2 days of head-down tilt

    NASA Technical Reports Server (NTRS)

    Frey, Mary A. B.; Mader, Thomas H.; Bagian, James P.; Charles, John B.; Meehan, Richard T.

    1993-01-01

    Spaceflight induces a cephalad redistribution of fluid volume and blood flow within the human body, and space motion sickness, which is a problem during the first few days of space flight, could be related to these changes in fluid status and in blood flow of the cerebrum and vestibular system. To evaluate possible changes in cerebral blood flow during simulated weightlessness, we measured blood velocity in the middle cerebral artery (MCA) along with retinal vascular diameters, intraocular pressure, impedance cardiography, and sphygmomanometry on nine men (26.2 +/- 6.6 yr) morning and evening for 2 days during continuous 10 deg head-down tilt (HDT). When subjects went from seated to head-down bed rest, their heart rate and retinal diameters decreased, and intraocular pressures increased. After 48 h of HDT, blood flow velocity in the MCA was decreased and thoracic impedance was increased, indicating less fluid in the thorax. Percent changes in blood flow velocities in the MCA after 48 h of HDT were inversely correlated with percent changes in retinal vascular diameters. Blood flow velocities in the MCA were inversely correlated (intersubject) with arterial pressures and retinal vascular diameters. Heart rate, stroke volume, cardiac output, systolic arterial pressure, and at times pulse pressure and blood flow velocities in the MCA were greater in the evening. Total peripheral resistance was higher in the morning. Although cerebral blood velocity is reduced after subjects are head down for 2 days, the inverse relationship with retinal vessel diameters, which have control analogous to that of cerebral vessels, indicates cerebral blood flow is not reduced.

  15. The Connective Tissue Components of Optic Nerve Head Cupping in Monkey Experimental Glaucoma Part 1: Global Change

    PubMed Central

    Yang, Hongli; Ren, Ruojin; Lockwood, Howard; Williams, Galen; Libertiaux, Vincent; Downs, Crawford; Gardiner, Stuart K.; Burgoyne, Claude F.

    2015-01-01

    Purpose To characterize optic nerve head (ONH) connective tissue change within 21 monkey experimental glaucoma (EG) eyes, so as to identify its principal components. Methods Animals were imaged three to five times at baseline then every 2 weeks following chronic unilateral IOP elevation, and euthanized early through end-stage confocal scanning laser tomographic change. Optic nerve heads were serial-sectioned, three-dimensionally (3D) reconstructed, delineated, and quantified. Overall EG versus control eye differences were assessed by general estimating equations (GEE). Significant, animal-specific, EG eye change was required to exceed the maximum physiologic intereye differences in six healthy animals. Results Overall EG eye change was significant (P < 0.0026) and animal-specific EG eye change most frequent, for five phenomena (number of EG eyes and range of animal-specific change): posterior laminar deformation (21, −29 to −437 μm), laminar thickening (11, 20–73 μm) and thinning (3, −23 to −31 μm), scleral canal expansion (17, 20–139 μm), outward anterior (16, −16 to −124 μm) and posterior (17, −22 to −279 μm) laminar insertion migration, and peripapillary scleral bowing (11, 21–77 μm). Experimental glaucoma versus control eye laminar thickness differences were bimodal in behavior, being thickened in most EG eyes demonstrating the least deformation and less thickened or thinned in most EG eyes demonstrating the greatest deformation. Conclusions Our postmortem studies retrospectively identify five connective tissue components of ONH “cupping” in monkey EG which serve as targets for longitudinally staging and phenotyping ONH connective tissue alteration within all forms of monkey and human optic neuropathy. PMID:26641545

  16. Comparison of the Deep Optic Nerve Head Structure between Normal-Tension Glaucoma and Nonarteritic Anterior Ischemic Optic Neuropathy

    PubMed Central

    Kim, Tae-Woo; Hwang, Jeong-Min

    2016-01-01

    Purpose To compare the deep optic nerve head (ONH) structure between normal-tension glaucoma (NTG) and nonarteritic anterior ischemic optic neuropathy (NAION) and also in healthy subjects as a control using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT). Methods This prospective cross-sectional study included 21 NAION patients who had been diagnosed as NAION at least 6 months prior to study entry, and 42 NTG patients and 42 healthy controls who were matched with NAION patients in terms of age, intraocular pressure (IOP), and optic disc area. The retinal nerve fiber layer (RNFL) thickness in the affected sector was also matched between NAION and NTG patients. The ONH was imaged using SD-OCT with the EDI technique. The anterior lamina cribrosa surface depth (LCD) and average prelaminar tissue (PT) thickness were measured in a sector of interest in each eye and compared among the three groups. Results In the sector-matched comparison, LCD was largest in NTG patients, followed by NAION patients, while PT was thinner in NTG patients than in NAION patients (all P < 0.001). NAION patients had a comparable LCD and a thinner PT relative to normal controls (P = 0.170 and < 0.001, respectively). Conclusion The deep ONH configuration is strikingly different between NTG and NAION. The differing features provide comparative insight into the pathophysiology of the two diseases, and may be useful for differential diagnosis. PMID:27035660

  17. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    PubMed Central

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-01-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the “non-progressing” and “progressing” glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection. PMID:25606299

  18. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    NASA Astrophysics Data System (ADS)

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-03-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the "non-progressing" and "progressing" glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection.

  19. Anatomical Attributes of the Optic Nerve Head in Eyes with Parafoveal Scotoma in Normal Tension Glaucoma

    PubMed Central

    Rao, Aparna; Mukherjee, Sujoy

    2014-01-01

    Purpose To evaluate optic nerve characteristics independent of systemic factors predisposing to parafoveal scotoma in normal tension glaucoma. Methods We included 40 patients with bilateral normal tension glaucoma with parafoveal scotoma (visual field defect in one hemifield within 10° of fixation with at least one point at p<1% lying at the two innermost paracentral points) in only one eye (Parafoveal group, PF, n = 40) identified from the hospital database in this observational cross sectional study. The other eye with no parafoveal scotoma constituted the control group (n = 32). Red free fundus photographs were evaluated using Image J software analyzing parameters including vertical and horizontal disc diameter, disc haemorrhage, location and angular width of the retinal nerve fibre layer depth and displacement of the central vessel trunk, CVT (vertical and horizontal). Clinical characteristics and disc parameters were compared in the two groups. Results The PF group had lower mean deviation(MD) and visual field index (VFI) and higher pattern standard deviation (PSD) than control group (p≤0.001) for similar untreated IOP, (p = 0.9). Disc haemorrhages were more frequent in the PF group, p = 0.01. The PF group had greater width of nerve fibre layer defects, p = 0.05 and greater vertical displacement of the central vessel trunk, p = 0.001. On multivariate logistic regression, parafoveal scotoma was significantly associated with increased vertical distance of the CVT, p = 0.0001. Conclusion Increased vertical displacement of the CVT is associated with parafoveal scotoma in normal tension glaucoma. Localising the vessel trunk may help clinicians in identifying patients at risk for parafoveal involvement. PMID:24595065

  20. Experimental Glaucoma Causes Optic Nerve Head Neural Rim Tissue Compression: A Potentially Important Mechanism of Axon Injury

    PubMed Central

    Fortune, Brad; Reynaud, Juan; Hardin, Christy; Wang, Lin; Sigal, Ian A.; Burgoyne, Claude F.

    2016-01-01

    Purpose We tested the hypothesis that experimental glaucoma (EG) results in greater thinning of the optic nerve head (ONH) neural rim tissue than the peripapillary retinal nerve fiber layer (RNFL) tissue. Methods Longitudinal spectral-domain optical coherence tomography (SDOCT) imaging of the ONH and peripapillary RNFL was performed every other week under manometric IOP control (10 mm Hg) in 51 nonhuman primates (NHP) during baseline and after induction of unilateral EG. The ONH parameter minimum rim area (MRA) was derived from 80 radial B-scans centered on the ONH; RNFL cross-sectional area (RNFLA) from a peripapillary circular B-scan with 12° diameter. Results In control eyes, MRA was 1.00 ± 0.19 mm2 at baseline and 1.00 ± 0.19 mm2 at the final session (P = 0.77), while RNFLA was 0.95 ± 0.09 and 0.95 ± 0.10 mm2, respectively (P = 0.96). In EG eyes, MRA decreased from 1.00 ± 0.19 mm2 at baseline to 0.63 ± 0.21 mm2 at the final session (P < 0.0001), while RNFLA decreased from 0.95 ± 0.09 to 0.74 ± 0.19 mm2, respectively (P < 0.0001). Thus, MRA decreased by 36.4 ± 20.6% in EG eyes, significantly more than the decrease in RNFLA (21.7 ± 19.4%, P < 0.0001). Other significant changes in EG eyes included increased Bruch's membrane opening (BMO) nonplanarity (P < 0.05), decreased BMO aspect ratio (P < 0.0001), and decreased MRA angle (P < 0.001). Bruch's membrane opening area did not change from baseline in either control or EG eyes (P = 0.27, P = 0.15, respectively). Conclusions Optic nerve head neural rim tissue thinning exceeded peripapillary RNFL thinning in NHP EG. These results support the hypothesis that axon bundles are compressed transversely within the ONH rim along with glaucomatous deformation of connective tissues. PMID:27564522

  1. The Role of Lumbar Sympathetic Nerves in Regulation of Blood Flow to Skeletal Muscle during Anaphylactic Hypotension in Anesthetized Rats

    PubMed Central

    Shibamoto, Toshishige; Zhang, Tao; Wang, Mofei; Kuda, Yuhichi; Kurata, Yasutaka

    2016-01-01

    During hypovolemic shock, skeletal muscle blood flow could be redistributed to vital organs via vasoconstriction in part evoked by activation of the innervating sympathetic nerve activity. However, it is not well known whether this mechanism operates during anaphylactic shock. We determined the femoral artery blood flow (FBF) and lumbar sympathetic nerve activity (LSNA) mainly regulating the hindquater muscle blood flow during anaphylactic hypotension in anesthetized rats. Anesthetized Sprague-Dawley rats were randomly allocated to the following groups (n = 7/group): (1) non-sensitized, (2) anaphylaxis, (3) anaphylaxis-lumbar sympathectomy (LS) and (4) anaphylaxis-sinoaortic denervation (SAD) groups. Anaphylaxis was induced by an intravenous injection of the ovalbumin antigen to the sensitized rats. The systemic arterial pressure (SAP), heart rate (HR), central venous pressure (CVP), FBF and LSNA were continuously measured. In the anaphylaxis group, LSNA and HR increased, while SAP and FBF decreased after antigen injection. In the anaphylaxis-SAD group, LSNA did not significantly change during the early phase, but the responses of SAP and FBF were similar to those in the anaphylaxis group. In the anaphylaxis-LS group, both FBF and SAP decreased similarly to the anaphylaxis group during anaphylactic hypotension. These results indicated that LSNA increased via baroreceptor reflex, but this sympathoexcitation or LS did not affect antigen-induced decreases in FBF or SAP. Lumbar sympathetic nerves are not involved in regulation of the blood flow to the hindlimb or systemic blood pressure during anaphylactic hypotension in anesthetized rats. PMID:26998924

  2. The Role of Lumbar Sympathetic Nerves in Regulation of Blood Flow to Skeletal Muscle during Anaphylactic Hypotension in Anesthetized Rats.

    PubMed

    Song, Jie; Tanida, Mamoru; Shibamoto, Toshishige; Zhang, Tao; Wang, Mofei; Kuda, Yuhichi; Kurata, Yasutaka

    2016-01-01

    During hypovolemic shock, skeletal muscle blood flow could be redistributed to vital organs via vasoconstriction in part evoked by activation of the innervating sympathetic nerve activity. However, it is not well known whether this mechanism operates during anaphylactic shock. We determined the femoral artery blood flow (FBF) and lumbar sympathetic nerve activity (LSNA) mainly regulating the hindquater muscle blood flow during anaphylactic hypotension in anesthetized rats. Anesthetized Sprague-Dawley rats were randomly allocated to the following groups (n = 7/group): (1) non-sensitized, (2) anaphylaxis, (3) anaphylaxis-lumbar sympathectomy (LS) and (4) anaphylaxis-sinoaortic denervation (SAD) groups. Anaphylaxis was induced by an intravenous injection of the ovalbumin antigen to the sensitized rats. The systemic arterial pressure (SAP), heart rate (HR), central venous pressure (CVP), FBF and LSNA were continuously measured. In the anaphylaxis group, LSNA and HR increased, while SAP and FBF decreased after antigen injection. In the anaphylaxis-SAD group, LSNA did not significantly change during the early phase, but the responses of SAP and FBF were similar to those in the anaphylaxis group. In the anaphylaxis-LS group, both FBF and SAP decreased similarly to the anaphylaxis group during anaphylactic hypotension. These results indicated that LSNA increased via baroreceptor reflex, but this sympathoexcitation or LS did not affect antigen-induced decreases in FBF or SAP. Lumbar sympathetic nerves are not involved in regulation of the blood flow to the hindlimb or systemic blood pressure during anaphylactic hypotension in anesthetized rats. PMID:26998924

  3. Sox10 Expression in Goldfish Retina and Optic Nerve Head in Controls and after the Application of Two Different Lesion Paradigms.

    PubMed

    Parrilla, Marta; León-Lobera, Fernando; Lillo, Concepción; Arévalo, Rosario; Aijón, José; Lara, Juan Manuel; Velasco, Almudena

    2016-01-01

    The mammalian central nervous system (CNS) is unable to regenerate. In contrast, the CNS of fish, including the visual system, is able to regenerate after damage. Moreover, the fish visual system grows continuously throughout the life of the animal, and it is therefore an excellent model to analyze processes of myelination and re-myelination after an injury. Here we analyze Sox10+ oligodendrocytes in the goldfish retina and optic nerve in controls and after two kinds of injuries: cryolesion of the peripheral growing zone and crushing of the optic nerve. We also analyze changes in a major component of myelin, myelin basic protein (MBP), as a marker for myelinated axons. Our results show that Sox10+ oligodendrocytes are located in the retinal nerve fiber layer and along the whole length of the optic nerve. MBP was found to occupy a similar location, although its loose appearance in the retina differed from the highly organized MBP+ axon bundles in the optic nerve. After optic nerve crushing, the number of Sox10+ cells decreased in the crushed area and in the optic nerve head. Consistent with this, myelination was highly reduced in both areas. In contrast, after cryolesion we did not find changes in the Sox10+ population, although we did detect some MBP- degenerating areas. We show that these modifications in Sox10+ oligodendrocytes are consistent with their role in oligodendrocyte identity, maintenance and survival, and we propose the optic nerve head as an excellent area for research aimed at better understanding of de- and remyelination processes. PMID:27149509

  4. Sox10 Expression in Goldfish Retina and Optic Nerve Head in Controls and after the Application of Two Different Lesion Paradigms

    PubMed Central

    Parrilla, Marta; León-Lobera, Fernando; Lillo, Concepción; Arévalo, Rosario; Aijón, José; Lara, Juan Manuel; Velasco, Almudena

    2016-01-01

    The mammalian central nervous system (CNS) is unable to regenerate. In contrast, the CNS of fish, including the visual system, is able to regenerate after damage. Moreover, the fish visual system grows continuously throughout the life of the animal, and it is therefore an excellent model to analyze processes of myelination and re-myelination after an injury. Here we analyze Sox10+ oligodendrocytes in the goldfish retina and optic nerve in controls and after two kinds of injuries: cryolesion of the peripheral growing zone and crushing of the optic nerve. We also analyze changes in a major component of myelin, myelin basic protein (MBP), as a marker for myelinated axons. Our results show that Sox10+ oligodendrocytes are located in the retinal nerve fiber layer and along the whole length of the optic nerve. MBP was found to occupy a similar location, although its loose appearance in the retina differed from the highly organized MBP+ axon bundles in the optic nerve. After optic nerve crushing, the number of Sox10+ cells decreased in the crushed area and in the optic nerve head. Consistent with this, myelination was highly reduced in both areas. In contrast, after cryolesion we did not find changes in the Sox10+ population, although we did detect some MBP- degenerating areas. We show that these modifications in Sox10+ oligodendrocytes are consistent with their role in oligodendrocyte identity, maintenance and survival, and we propose the optic nerve head as an excellent area for research aimed at better understanding of de- and remyelination processes. PMID:27149509

  5. Cerebrospinal Fluid Hypernatremia Elevates Sympathetic Nerve Activity and Blood Pressure via the Rostral Ventrolateral Medulla.

    PubMed

    Stocker, Sean D; Lang, Susan M; Simmonds, Sarah S; Wenner, Megan M; Farquhar, William B

    2015-12-01

    Elevated NaCl concentrations of the cerebrospinal fluid increase sympathetic nerve activity (SNA) in salt-sensitive hypertension. Neurons of the rostral ventrolateral medulla (RVLM) play a pivotal role in the regulation of SNA and receive mono- or polysynaptic inputs from several hypothalamic structures responsive to hypernatremia. Therefore, the present study investigated the contribution of RVLM neurons to the SNA and pressor response to cerebrospinal fluid hypernatremia. Lateral ventricle infusion of 0.15 mol/L, 0.6 mol/L, and 1.0 mol/L NaCl (5 µL/10 minutes) produced concentration-dependent increases in lumbar SNA, adrenal SNA, and arterial blood pressure, despite no change in splanchnic SNA and a decrease in renal SNA. Ganglionic blockade with chlorisondamine or acute lesion of the lamina terminalis blocked or significantly attenuated these responses, respectively. RVLM microinjection of the gamma-aminobutyric acid (GABAA) agonist muscimol abolished the sympathoexcitatory response to intracerebroventricular infusion of 1 mol/L NaCl. Furthermore, blockade of ionotropic glutamate, but not angiotensin II type 1, receptors significantly attenuated the increase in lumbar SNA, adrenal SNA, and arterial blood pressure. Finally, single-unit recordings of spinally projecting RVLM neurons revealed 3 distinct populations based on discharge responses to intracerebroventricular infusion of 1 mol/L NaCl: type I excited (46%; 11/24), type II inhibited (37%; 9/24), and type III no change (17%; 4/24). All neurons with slow conduction velocities were type I cells. Collectively, these findings suggest that acute increases in cerebrospinal fluid NaCl concentrations selectively activate a discrete population of RVLM neurons through glutamate receptor activation to increase SNA and arterial blood pressure. PMID:26416846

  6. Does tranexamic acid reduce blood loss during head and neck cancer surgery?

    PubMed Central

    Kulkarni, Atul P; Chaukar, Devendra A; Patil, Vijaya P; Metgudmath, Rajendra B; Hawaldar, Rohini W; Divatia, Jigeeshu V

    2016-01-01

    Background and Aims: Transfusion of blood and blood products poses several hazards. Antifibrinolytic agents are used to reduce perioperative blood loss. We decided to assess the effect of tranexamic acid (TA) on blood loss and the need for transfusion in head and neck cancer surgery. Methods: After Institutional Review Board approval, 240 patients undergoing supramajor head and neck cancer surgeries were prospectively randomised to either TA (10 mg/kg) group or placebo (P) group. After induction, the drug was infused by the anaesthesiologist, who was blinded to allocation, over 20 min. The dose was repeated every 3 h. Perioperative (up to 24 h) blood loss, need for transfusion and fluid therapy was recorded. Thromboelastography (TEG) was performed at fixed intervals in the first 100 patients. Patients were watched for post-operative complications. Results: Two hundred and nineteen records were evaluable. We found no difference in intraoperative blood loss (TA - 750 [600–1000] ml vs. P - 780 [150–2600] ml, P = 0.22). Post-operative blood loss was significantly more in the placebo group at 24 h (P - 200 [120–250] ml vs. TA - 250 [50–1050] ml, P = 0.009), but this did not result in higher number of patients needing transfusions (TA - 22/108 and P - 27/111 patients, P = 0.51). TEG revealed faster clot formation and minimal fibrinolysis. Two patients died of causes unrelated to study drug. Incidence of wound complications and deep venous thrombosis was similar. Conclusion: In head and neck cancer surgery, TA did not reduce intraoperative blood loss or need for transfusions. Perioperative TEG variables were similar. This may be attributed to pre-existing hypercoagulable state and minimal fibrinolysis in cancer patients. PMID:26962250

  7. Influence of long-term head-down body position on innervation density in extremity blood vessels

    NASA Technical Reports Server (NTRS)

    Lorant, M.; Raffai, G.; Nadasy, G.; Feher, E.; Monos, E.

    2001-01-01

    The aim of the present study was to quantitate and compare the density of nerve terminals (NTD), as well as of their synaptic vesicle population (SyVD) in saphenous and brachial vein and artery, obtained from rats maintained in the horizontal or head-down tilted (HDT) position for two weeks. The same technique was applied as that for the head-up tilt study.

  8. Lipid Composition of the Human Eye: Are Red Blood Cells a Good Mirror of Retinal and Optic Nerve Fatty Acids?

    PubMed Central

    Acar, Niyazi; Berdeaux, Olivier; Grégoire, Stéphane; Cabaret, Stéphanie; Martine, Lucy; Gain, Philippe; Thuret, Gilles; Creuzot-Garcher, Catherine P.; Bron, Alain M.; Bretillon, Lionel

    2012-01-01

    Background The assessment of blood lipids is very frequent in clinical research as it is assumed to reflect the lipid composition of peripheral tissues. Even well accepted such relationships have never been clearly established. This is particularly true in ophthalmology where the use of blood lipids has become very common following recent data linking lipid intake to ocular health and disease. In the present study, we wanted to determine in humans whether a lipidomic approach based on red blood cells could reveal associations between circulating and tissue lipid profiles. To check if the analytical sensitivity may be of importance in such analyses, we have used a double approach for lipidomics. Methodology and Principal Findings Red blood cells, retinas and optic nerves were collected from 9 human donors. The lipidomic analyses on tissues consisted in gas chromatography and liquid chromatography coupled to an electrospray ionization source-mass spectrometer (LC-ESI-MS). Gas chromatography did not reveal any relevant association between circulating and ocular fatty acids except for arachidonic acid whose circulating amounts were positively associated with its levels in the retina and in the optic nerve. In contrast, several significant associations emerged from LC-ESI-MS analyses. Particularly, lipid entities in red blood cells were positively or negatively associated with representative pools of retinal docosahexaenoic acid (DHA), retinal very-long chain polyunsaturated fatty acids (VLC-PUFA) or optic nerve plasmalogens. Conclusions and Significance LC-ESI-MS is more appropriate than gas chromatography for lipidomics on red blood cells, and further extrapolation to ocular lipids. The several individual lipid species we have identified are good candidates to represent circulating biomarkers of ocular lipids. However, further investigation is needed before considering them as indexes of disease risk and before using them in clinical studies on optic nerve

  9. The role of blood vessels in high-resolution volume conductor head modeling of EEG.

    PubMed

    Fiederer, L D J; Vorwerk, J; Lucka, F; Dannhauer, M; Yang, S; Dümpelmann, M; Schulze-Bonhage, A; Aertsen, A; Speck, O; Wolters, C H; Ball, T

    2016-03-01

    Reconstruction of the electrical sources of human EEG activity at high spatio-temporal accuracy is an important aim in neuroscience and neurological diagnostics. Over the last decades, numerous studies have demonstrated that realistic modeling of head anatomy improves the accuracy of source reconstruction of EEG signals. For example, including a cerebro-spinal fluid compartment and the anisotropy of white matter electrical conductivity were both shown to significantly reduce modeling errors. Here, we for the first time quantify the role of detailed reconstructions of the cerebral blood vessels in volume conductor head modeling for EEG. To study the role of the highly arborized cerebral blood vessels, we created a submillimeter head model based on ultra-high-field-strength (7T) structural MRI datasets. Blood vessels (arteries and emissary/intraosseous veins) were segmented using Frangi multi-scale vesselness filtering. The final head model consisted of a geometry-adapted cubic mesh with over 17×10(6) nodes. We solved the forward model using a finite-element-method (FEM) transfer matrix approach, which allowed reducing computation times substantially and quantified the importance of the blood vessel compartment by computing forward and inverse errors resulting from ignoring the blood vessels. Our results show that ignoring emissary veins piercing the skull leads to focal localization errors of approx. 5 to 15mm. Large errors (>2cm) were observed due to the carotid arteries and the dense arterial vasculature in areas such as in the insula or in the medial temporal lobe. Thus, in such predisposed areas, errors caused by neglecting blood vessels can reach similar magnitudes as those previously reported for neglecting white matter anisotropy, the CSF or the dura - structures which are generally considered important components of realistic EEG head models. Our findings thus imply that including a realistic blood vessel compartment in EEG head models will be helpful to

  10. Persistent effects after trigeminal nerve proprioceptive stimulation by mandibular extension on rat blood pressure, heart rate and pial microcirculation.

    PubMed

    Lapi, D; Colantuoni, A; Del Seppia, C; Ghione, S; Tonlorenzi, D; Brunelli, M; Scuri, R

    2013-03-01

    The trigemino-cardiac reflex is a brainstem reflex known to lead to a decrement in heart rate and blood pressure, whereas few data have been collected about its effects on the cerebral hemodynamic. In this study we assess the in vivo effects of trigeminal nerve peripheral stimulation by mandibular extension on pial microcirculation and systemic arterial blood pressure in rats. Experiments were performed in male Wistar rats subjected to mandibular extension obtained inserting an ad hoc developed retractor between the dental arches. Mean arterial blood pressure and heart rate were recorded and the pial arterioles were visualized by fluorescence microscopy to measure the vessel diameters before (15 minutes) during (5-15 minutes) and after (80 minutes) mandibular extension. While in control rats (sham-operated rats) and in rats subjected to the dissection of the trigeminal peripheral branches mean arterial blood pressure, heart rate and pial microcirculation did not change during the whole observation period (110 minutes), in rats submitted to mandibular extension, mean arterial blood pressure, heart rate and arteriolar diameter significantly decreased during stimulation. Afterward mean arterial blood pressure remained reduced as well as heart rate, while arteriolar diameter significantly increased evidencing a vasodilatation persisting for the whole remaining observation time. Therefore, trigeminal nerve proprioceptive stimulation appears to trigger specific mechanisms regulating systemic arterial blood pressure and pial microcirculation. PMID:23807620

  11. Intraoperative radiation of canine carotid artery, internal jugular vein, and vagus nerve. Therapeutic applications in the management of advanced head and neck cancers

    SciTech Connect

    Mittal, B.B.; Pelzer, H.; Tsao, C.S.; Ward, W.F.; Johnson, P.; Friedman, C.; Sisson, G.A. Sr.; Kies, M. )

    1990-12-01

    As a step in the application of intraoperative radiotherapy (IORT) for treating advanced head and neck cancers, preliminary information was obtained on the radiation tolerance of the canine common carotid artery, internal jugular vein, and vagus nerve to a single, high-dose electron beam. Both sides of the neck of eight mongrel dogs were operated on to expose an 8-cm segment of common carotid artery, internal jugular vein, and vagus nerve. One side of the neck was irradiated, using escalating doses of 2500, 3500, 4500, and 5500 cGy. The contralateral side of the neck served as the unirradiated control. At 3 and 6 months after IORT, one dog at each dose level was killed. None of the dogs developed carotid bleeding at any time after IORT. Light microscopic investigations using hematoxylin-eosin staining on the common carotid artery and internal jugular vein showed no consistent changes that suggested radiation damage; however, the Masson trichrome stain and hydroxyproline concentration of irradiated common carotid artery indicated an increase in the collagen content of the tunica media. Marked changes in the irradiated vagus nerve were seen, indicating severe demyelination and loss of nerve fibers, which appeared to be radiation-dose dependent. Four patients with advanced recurrent head and neck cancer were treated with surgical resection and IORT without any acute or subacute complications. The role of IORT as a supplement to surgery, external beam irradiation, and chemotherapy in selected patients with advanced head and neck cancer needs further exploration.

  12. Ultrahigh-Speed Optical Coherence Tomography for Three-Dimensional and En Face Imaging of the Retina and Optic Nerve Head

    PubMed Central

    Srinivasan, Vivek J.; Adler, Desmond C.; Chen, Yueli; Gorczynska, Iwona; Huber, Robert; Duker, Jay S.; Schuman, Joel S.; Fujimoto, James G.

    2009-01-01

    Purpose To demonstrate ultrahigh-speed optical coherence tomography (OCT) imaging of the retina and optic nerve head at 249,000 axial scans per second and a wavelength of 1060 nm. To investigate methods for visualization of the retina, choroid, and optic nerve using high-density sampling enabled by improved imaging speed. Methods A swept-source OCT retinal imaging system operating at a speed of 249,000 axial scans per second was developed. Imaging of the retina, choroid, and optic nerve were performed. Display methods such as speckle reduction, slicing along arbitrary planes, en face visualization of reflectance from specific retinal layers, and image compounding were investigated. Results High-definition and three-dimensional (3D) imaging of the normal retina and optic nerve head were performed. Increased light penetration at 1060 nm enabled improved visualization of the choroid, lamina cribrosa, and sclera. OCT fundus images and 3D visualizations were generated with higher pixel density and less motion artifacts than standard spectral/Fourier domain OCT. En face images enabled visualization of the porous structure of the lamina cribrosa, nerve fiber layer, choroid, photoreceptors, RPE, and capillaries of the inner retina. Conclusions Ultrahigh-speed OCT imaging of the retina and optic nerve head at 249,000 axial scans per second is possible. The improvement of ∼5 to 10× in imaging speed over commercial spectral/Fourier domain OCT technology enables higher density raster scan protocols and improved performance of en face visualization methods. The combination of the longer wavelength and ultrahigh imaging speed enables excellent visualization of the choroid, sclera, and lamina cribrosa. PMID:18658089

  13. Longitudinal Change Detected by Spectral Domain Optical Coherence Tomography in the Optic Nerve Head and Peripapillary Retina in Experimental Glaucoma

    PubMed Central

    Strouthidis, Nicholas G.; Fortune, Brad; Yang, Hongli; Sigal, Ian A.

    2011-01-01

    Purpose. To investigate whether longitudinal changes deep within the optic nerve head (ONH) are detectable by spectral domain optical coherence tomography (SDOCT) in experimental glaucoma (EG) and whether these changes are detectable at the onset of Heidelberg Retina Tomography (HRT; Heidelberg Engineering, Heidelberg, Germany)–defined surface topography depression. Methods. Longitudinal SDOCT imaging (Spectralis; Heidelberg Engineering) was performed in both eyes of nine rhesus macaques every 1 to 3 weeks. One eye of each underwent trabecular laser-induced IOP elevation. Four masked operators delineated internal limiting membrane (ILM), retinal nerve fiber layer (RNFL), Bruch's membrane/retinal pigment epithelium (BM/RPE), neural canal opening (NCO), and anterior lamina cribrosa surface (ALCS) by using custom software. Longitudinal changes were assessed and compared between the EG and control (nonlasered) eyes at the onset of HRT-detected surface depression (follow-up 1; [FU1]) and at the most recent image (follow-up 2; [FU2]). Results. Mean IOP in EG eyes was 7.1 to 24.6 mm Hg at FU1 and 13.5 to 31.9 mm Hg at FU2. In control eyes, the mean IOP was 7.2 to 12.6 mm Hg (FU1) and 8.9 to 16.0 mm Hg (FU2). At FU1, neuroretinal rim decreased and ALCS depth increased significantly (paired t-test, P < 0.01); no change in RNFL thickness was detected. At FU2, however, significant prelaminar tissue thinning, posterior displacement of NCO, and RNFL thinning were observed. Conclusions. Longitudinal SDOCT imaging can detect deep ONH changes in EG eyes, the earliest of which are present at the onset of HRT-detected ONH surface height depression. These parameters represent realistic targets for SDOCT detection of glaucomatous progression in human subjects. PMID:21217108

  14. Longitudinal Detection of Optic Nerve Head Changes by Spectral Domain Optical Coherence Tomography in Early Experimental Glaucoma

    PubMed Central

    He, Lin; Yang, Hongli; Gardiner, Stuart K.; Williams, Galen; Hardin, Christy; Strouthidis, Nicholas G.; Fortune, Brad; Burgoyne, Claude F.

    2014-01-01

    Purpose. We determined if the detection of spectral-domain optical coherence tomography (SDOCT) optic nerve head (ONH) change precedes the detection of confocal scanning laser tomography (CSLT) ONH surface, SDOCT retinal nerve fiber layer (RNFL), scanning laser perimetry (SLP), and multifocal electroretinography (mfERG) change in eight experimental glaucoma (EG) eyes. Methods. Both eyes from eight monkeys were tested at least three times at baseline, and then every 2 weeks following laser-induced chronic unilateral IOP elevation. Event and trend-based definitions of onset in the control and EG eyes for 11 SDOCT neural and connective tissue, CSLT surface, SDOCT RNFL, SLP, and mfERG parameters were explored. The frequency and timing of onset for each parameter were compared using a logrank test. Results. Maximum post-laser IOP was 18 to 42 mm Hg in the EG eyes and 12 to 20 mm Hg in the control eyes. For event- and trend-based analyses, onsets were achieved earliest and most frequently within the ONH neural and connective tissues using SDOCT, and at the ONH surface using CSLT. SDOCT ONH neural and connective tissue parameter change preceded or coincided with CSLT ONH surface change in most EG eyes. The SDOCT and SLP measures of RNFL thickness, and mfERG measures of visual function demonstrated similar onset rates, but occurred later than SDOCT ONH and CSLT surface change, and in fewer eyes. Conclusions. SDOCT ONH change detection commonly precedes or coincides with CSLT ONH surface change detection, and consistently precedes RNFLT, SLP, and mfERG change detection in monkey experimental glaucoma. PMID:24255047

  15. Blood-nerve barrier: distribution of anionic sites on the endothelial plasma membrane and basal lamina of dorsal root ganglia.

    PubMed

    Bush, M S; Reid, A R; Allt, G

    1991-09-01

    Previous investigations of the blood-nerve barrier have correlated the greater permeability of ganglionic endoneurial vessels, compared to those of nerve trunks, with the presence of fenestrations and open intercellular junctions. Recent studies have demonstrated reduced endothelial cell surface charge in blood vessels showing greater permeability. To determine the distribution of anionic sites on the plasma membranes and basal laminae of endothelial cells in dorsal root ganglia, cationic colloidal gold and cationic ferritin were used. Electron microscopy revealed the existence of endothelial microdomains with differing labelling densities. Labelling indicated that caveolar and fenestral diaphragms and basal laminae are highly anionic at physiological pH, luminal plasma membranes and endothelial processes are moderately charged and abluminal plasma membranes are weakly anionic. Tracers did not occur in caveolae or cytoplasmic vesicles. In vitro tracer experiments at pH values of 7.3, 5.0, 3.5 and 2.0 indicated that the anionic charge on the various endothelial domains was contributed by chemical groups with differing pKa values. In summary, the labelling of ganglionic and sciatic nerve vessels was similar except for the heavy labelling of diaphragms in a minority of endoneurial vessels in ganglia. This difference is likely to account in part for the greater permeability of ganglionic endoneurial vessels. The results are discussed with regard to the blood-nerve and -brain barriers and vascular permeability in other tissues and a comparison made between the ultrastructure and anionic microdomains of epi-, peri- and endoneurial vessels of dorsal root ganglia and sciatic nerves. PMID:1960538

  16. Electrical Stimulation of the Ear, Head, Cranial Nerve, or Cortex for the Treatment of Tinnitus: A Scoping Review

    PubMed Central

    Adjamian, Peyman

    2016-01-01

    Tinnitus is defined as the perception of sound in the absence of an external source. It is often associated with hearing loss and is thought to result from abnormal neural activity at some point or points in the auditory pathway, which is incorrectly interpreted by the brain as an actual sound. Neurostimulation therapies therefore, which interfere on some level with that abnormal activity, are a logical approach to treatment. For tinnitus, where the pathological neuronal activity might be associated with auditory and other areas of the brain, interventions using electromagnetic, electrical, or acoustic stimuli separately, or paired electrical and acoustic stimuli, have been proposed as treatments. Neurostimulation therapies should modulate neural activity to deliver a permanent reduction in tinnitus percept by driving the neuroplastic changes necessary to interrupt abnormal levels of oscillatory cortical activity and restore typical levels of activity. This change in activity should alter or interrupt the tinnitus percept (reduction or extinction) making it less bothersome. Here we review developments in therapies involving electrical stimulation of the ear, head, cranial nerve, or cortex in the treatment of tinnitus which demonstrably, or are hypothesised to, interrupt pathological neuronal activity in the cortex associated with tinnitus. PMID:27403346

  17. Automated discovery of structural features of the optic nerve head on the basis of image and genetic data

    NASA Astrophysics Data System (ADS)

    Christopher, Mark; Tang, Li; Fingert, John H.; Scheetz, Todd E.; Abramoff, Michael D.

    2014-03-01

    Evaluation of optic nerve head (ONH) structure is a commonly used clinical technique for both diagnosis and monitoring of glaucoma. Glaucoma is associated with characteristic changes in the structure of the ONH. We present a method for computationally identifying ONH structural features using both imaging and genetic data from a large cohort of participants at risk for primary open angle glaucoma (POAG). Using 1054 participants from the Ocular Hypertension Treatment Study, ONH structure was measured by application of a stereo correspondence algorithm to stereo fundus images. In addition, the genotypes of several known POAG genetic risk factors were considered for each participant. ONH structural features were discovered using both a principal component analysis approach to identify the major modes of variance within structural measurements and a linear discriminant analysis approach to capture the relationship between genetic risk factors and ONH structure. The identified ONH structural features were evaluated based on the strength of their associations with genotype and development of POAG by the end of the OHTS study. ONH structural features with strong associations with genotype were identified for each of the genetic loci considered. Several identified ONH structural features were significantly associated (p < 0.05) with the development of POAG after Bonferroni correction. Further, incorporation of genetic risk status was found to substantially increase performance of early POAG prediction. These results suggest incorporating both imaging and genetic data into ONH structural modeling significantly improves the ability to explain POAG-related changes to ONH structure.

  18. Local Relationship between Global-Flash Multifocal Electroretinogram Optic Nerve Head Components and Visual Field Defects in Patients with Glaucoma

    PubMed Central

    Moon, Chan Hee; Han, Jungwoo; Ohn, Young-Hoon; Park, Tae Kwann

    2015-01-01

    Purpose. To investigate the local relationship between quantified global-flash multifocal electroretinogram (mfERG) optic nerve head component (ONHC) and visual field defects in patients with glaucoma. Methods. Thirty-nine patients with glaucoma and 30 normal controls were enrolled. The ONHC amplitude was measured from the baseline to the peak of the second positive deflection of the induced component. The ONHC amplitude was normalized by dividing ONHC amplitude by the average of seven largest ONHC amplitudes. The ONHC amplitude ratio map and ONHC deficiency map were constructed. The local relationship between the ONHC measurements and visual field defects was evaluated by calculating the overlap between the ONHC deficiency maps and visual field defect plots. Results. The mean ONHC amplitude measurements of patients with glaucoma (6.01 ± 1.91 nV/deg2) were significantly lower than those of the normal controls (10.29 ± 0.94 nV/deg2) (P < 0.001). The average overlap between the ONHC deficiency map and visual field defect plot was 71.4%. The highest overlap (75.0%) was between the ONHC ratios less than 0.5 and the total deviations less than 5%. Conclusions. The ONHC amplitude was reduced in patients with glaucoma compared to that in normal controls. Loss of the ONHC amplitude from the global-flash mfERG showed a high local agreement with visual field defects in patients with glaucoma. PMID:26697210

  19. Quantitative analysis of three-dimensional fibrillar collagen microstructure within the normal, aged and glaucomatous human optic nerve head

    PubMed Central

    Jones, H. J.; Girard, M. J.; White, N.; Fautsch, M. P.; Morgan, J. E.; Ethier, C. R.; Albon, J.

    2015-01-01

    The aim of this study was to quantify connective tissue fibre orientation and alignment in young, old and glaucomatous human optic nerve heads (ONH) to understand ONH microstructure and predisposition to glaucomatous optic neuropathy. Transverse (seven healthy, three glaucomatous) and longitudinal (14 healthy) human ONH cryosections were imaged by both second harmonic generation microscopy and small angle light scattering (SALS) in order to quantify preferred fibre orientation (PFO) and degree of fibre alignment (DOFA). DOFA was highest within the peripapillary sclera (ppsclera), with relatively low values in the lamina cribrosa (LC). Elderly ppsclera DOFA was higher than that in young ppsclera (p < 0.00007), and generally higher than in glaucoma ppsclera. In all LCs, a majority of fibres had preferential orientation horizontally across the nasal–temporal axis. In all glaucomatous LCs, PFO was significantly different from controls in a minimum of seven out of 12 LC regions (p < 0.05). Additionally, higher fibre alignment was observed in the glaucomatous inferior–temporal LC (p < 0.017). The differences between young and elderly ONH fibre alignment within regions suggest that age-related microstructural changes occur within the structure. The additional differences in fibre alignment observed within the glaucomatous LC may reflect an inherent susceptibility to glaucomatous optic neuropathy, or may be a consequence of ONH remodelling and/or collapse. PMID:25808336

  20. Fibre optic confocal imaging (FOCI) of keratinocytes, blood vessels and nerves in hairless mouse skin in vivo

    PubMed Central

    BUSSAU, L. J.; VO, L. T.; DELANEY, P. M.; PAPWORTH, G. D.; BARKLA, D. H.; KING, R. G.

    1998-01-01

    Fibre optic confocal imaging (FOCI) enabled subsurface fluorescence microscopy of the skin of hairless mice in vivo. Application of acridine orange enabled imaging of the layers of the epidermis. The corneocytes of the stratum corneum, the keratinocytes in the basal layers and redundant hair follicles were visualised at depths greater than 100 μm. Cellular and nuclear membranes of keratinocytes of the skin were visualised by the use of acridine orange and DIOC5(3). Imaging of the skin after injection of FITC-dextran revealed an extensive network of blood vessels with a size range up to 20 μm. Blood cells could be seen moving through dermal vessels and the blood circulation through the dermal vascular bed was video-taped. The fluorescent dye 4-di-2-ASP showed the presence of nerves fibres around the hair follicles and subsurface blood vessels. Comparison was made between images obtained in vivo using FOCI and in vitro scanning electron microscopy and conventional histology. FOCI offers the potential to study dynamic events in vivo, such as blood flow, skin growth, nerve regeneration and many pathological processes, in ways which have not previously been possible. PMID:9643419

  1. Association between optic nerve blood flow and objective examinations in glaucoma patients with generalized enlargement disc type

    PubMed Central

    Chiba, Naoki; Omodaka, Kazuko; Yokoyama, Yu; Aizawa, Naoko; Tsuda, Satoru; Yasuda, Masayuki; Otomo, Takaaki; Yokokura, Shunji; Fuse, Nobuo; Nakazawa, Toru

    2011-01-01

    Background The purpose of this study was to investigate the correlations between microcirculation in the optic disc, average peripapillary retinal nerve fiber layer thickness cupping parameters, and visual field defects in glaucoma patients with the generalized enlargement disc type. Methods A total of 38 eyes from 38 glaucoma patients with the generalized enlargement disc type were included. The microcirculation of the optic nerve head was examined with laser speckle flow graphy, and the mean blur rate in all areas, in vessel area, and in tissue area were calculated using the laser speckle flow graphy analyzer software. Average peripapillary retinal nerve fiber layer thickness was measured using Stratus optical coherence tomography, and cupping parameters were accessed using the Heidelberg retina tomograph. The mean deviation in the Humphrey field analyzer (30-2 SITA standard) was analyzed. The correlation between these parameters was evaluated using the Spearman rank correlation coefficient. Results The correlation coefficient of mean blur rate in all optic disc area to the average peripapillary retinal nerve fiber layer thickness, vertical C/D, and mean deviation were r = 0.7546 (P < 0.0001), r = −0.6208 (P < 0.0001), and r = 0.6010 (P = 0.0001), respectively. The mean blur rate in tissue area of the optic disc showed r = 0.7305 (P < 0.0001), r = −0.6438 (P < 0.0001), and r = 0.6338 (P < 0.0001). Conclusion We found that the mean blur rate in the optic disc was significantly correlated with the average peripapillary retinal nerve fiber layer thickness, vertical C/D, and mean deviation in patients with the generalized enlargement disc type of glaucoma. In particular, the mean blur rate in tissue area was more highly correlated than the vessel area with other results of examination in glaucoma patients with the generalized enlargement disc type. PMID:22125400

  2. Influence of two anesthetic techniques on blood sugar level in head injury patients: A comparative study

    PubMed Central

    Kumar, Manoj; Tripathi, Manoj; Malviya, Deepak; Malviya, P. S.; Kumar, Virendra; Tyagi, Amit

    2016-01-01

    Background: Head injury presents a major worldwide social, economic, and health problem. Hyperglycemia is a significant indicator of the severity of injury and predictor of outcome, which can easily be prevented. There has been a long-standing controversy regarding the use of inhalational or intravenous (i.v.) anesthetic agents for surgery of head injury cases and impact of these agents on blood sugar level. Aims and Objectives: The aim of this study is to find out anesthetic drugs and technique having minimal or no effect on the blood sugar, and Glasgow Coma Scale (GCS) of patients with a head injury by comparing two types of anesthetic techniques in surgery of head injury patients. Materials and Methods: This was a prospective, randomized, and comparative study, conducted on 60 adult head injury patients. The patients were divided into two groups of 30 each. Group I patients received induction with sevoflurane and then had O2 + air + sevoflurane for maintenance with controlled ventilation. Group II patients received induction with i.v. propofol and then had O2 + air + propofol for maintenance with controlled ventilation. Injection fentanyl was used in both the groups at the time of induction and in intermittent boluses in maintenance. In observation, blood sugar level and mean arterial pressure were assessed at different time periods perioperatively in both groups while GCS was analyzed pre- and post-operatively. Statistical Analysis: Statistical analysis was performed by Microsoft Excel 2010 using t-test for comparison between the two groups and Z-test for comparison of proportions. Results and Conclusion: Blood sugar level was found significantly higher in patients of sevoflurane group at 30 min after induction, at the end of surgery, and 1 h after the end of anesthesia than propofol group patients. This increase of blood sugar level did not have any significant alteration in the GCS profile of the patients in sevoflurane group as compared to propofol group

  3. The Correlation of Retinal Nerve Fiber Layer Thickness With Blood Pressure in a Chinese Hypertensive Population

    PubMed Central

    Gangwani, Rita A.; Lee, Jacky W.Y.; Mo, H.Y.; Sum, Rita; Kwong, Alfred S.K.; Wang, Jenny H.L.; Tsui, Wendy W.S.; Chan, Jonathan C.H.; Lai, Jimmy S.M.

    2015-01-01

    Abstract To investigate the association between retinal nerve fiber layer (RNFL) thickness and blood pressure (BP) in subjects with systemic hypertension. Subjects with systemic hypertension on anti-hypertensive medications were screened by fundus photography and referred for glaucoma work-up if there was enlarged vertical cup-to-disc (VCDR) ratio ≥0.6, VCDR asymmetry ≥0.2, or optic disc hemorrhage. Workup included a complete ophthalmological examination, Humphrey visual field test, and RNFL thickness measurement by optical coherence tomography. The intraocular pressure (IOP) and RNFL thicknesses (global and quadrant) were averaged from both eyes and the means were correlated with: the systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP) using Pearson correlation. Among 4000 screened hypertensive subjects, 133 were referred for glaucoma workup and 110 completed the workup. Of the 4000 screened subjects, 1.3% had glaucoma (0.9% had normal tension glaucoma [NTG], 0.2% had primary open angle glaucoma, and 0.2% had primary angle closure glaucoma), whereas 0.3% were NTG suspects. The SBP was negatively correlated with the mean superior RNFL thickness (P = 0.01). The DBP was negatively correlated with the mean global (P = 0.03), superior (P = 0.02), and nasal (P = 0.003) RNFL thickness. The MAP was negatively correlated with the mean global (P = 0.01), superior (P = 0.002), and nasal (P = 0.004) RNFL thickness while positively correlated with the mean IOP (P = 0.02). In medically treated hypertensive subjects, glaucoma was present in 1.3%, with NTG being most prevalent. MAP control may help with IOP lowering and RNFL preservation, although future prospective studies will be needed. PMID:26061324

  4. The influence of the splanchnic nerves on the external secretion, blood flow and electrical conductance of the cat pancreas

    PubMed Central

    Barlow, T. E.; Greenwell, J. R.; Harper, A. A.; Scratcherd, T.

    1974-01-01

    1. Electrical stimulation of the cut peripheral end of the splanchnic nerves results in a biphasic change in electrical conductance measured across the tail of the pancreas. A phase of decreased conductance is followed by a more prolonged phase of increased conductance. 2. Simultaneous measurements of pancreatic blood flow indicate that the phase of decreased conductance occurs as a result of vasoconstriction, whilst the phase of increased conductance is due to vasodilatation. 3. The initial phase of decreased conductance and vasoconstriction is abolished by α-receptor blocking agents such as phenoxybenzamine and the phase of increased conductance blocked by β-receptor blocking agents such as pronethalol. 4. Short periods of electrical stimulation applied to the splanchnic nerves result in a secretion of amylase and a reduction in the volume rate of secretion. 5. When the vasoconstrictor response was abolished by phenoxybenzamine, nerve stimulation still reduced the rate of secretion, suggesting that the inhibitory effect is in part due to a direct action of the secretory cells. 6. After bretylium tosylate, splanchnic nerve stimulation no longer produced vasomotor changes in the pancreas and the inhibitory effect on the volume response was converted to one of augmentation, but the secretion of enzymes was unaffected. 7. The secretion of amylase on splanchnic stimulation was abolished by intravenous injection of atropine, suggesting that a cholinergic mechanism is involved. 8. Noradrenaline did not mobilize pancreatic enzymes. PMID:16992444

  5. Simulated Microgravity Increases Cutaneous Blood Flow in the Head and Leg of Humans

    NASA Technical Reports Server (NTRS)

    Stout, M. Shannon; Watenpaugh, Donald E.; Breit, Gregory A.; Hargens, Alan R.

    1995-01-01

    The cutaneous micro-circulation vasodilates during acute 6 deg. head-down tilt (HDT, simulated microgravity) relative to upright conditions, more in the lower body than in the upper body. We expected that relative magnitudes of and differences between upper and lower body cutaneous blood flow elevation would be sustained during initial acclimation to simulated microgravity. We measured cutaneous micro-vascular blood flow with laser-Doppler flowmetry at the leg (over the distal tibia) and cheek (over the zygomatic arch) of eight healthy men before, during, and after 24 h of HDT. Results were calculated as a percentage of baseline value (100% measured during pre-tilt upright sitting). Cutaneous blood flow in the cheek increased significantly to 165 +/- 37% (mean + SE, p less than 0.05) at 9-12 h HDT, then returned to near baseline values by 24 h HDT (114 +/- 29%, NSD), despite increased local arterial pressure. Microvascular flow in the leg remained significantly elevated above baseline throughout 24 h HDT (427 +/- 85% at 3 h HDT and 215 +/- 142% at 24 h HDT, p less than 0.05). During the 6-h upright sitting recovery period, cheek and leg blood flow levels returned to near pre-tilt baseline values. Because hydrostatic effects of HDT increase local arterial pressure at the carotid sinus, baroreflex-mediated withdrawal of sympathetic tone probably contributed to increased microvascular flows at the head and leg during HDT. In the leg, baroreflex effects combined with minimal stimulation of local veno-arteriolar and myogenic autoregulatory vasoconstriction to elicit relatively larger and more sustained increases in cutaneous flow during HDT. In the cheek, delayed myogenic vasoconstriction and/or humoral effects apparently compensated for flow elevation by 24 h of HDT. Therefore, localized vascular adaptations to gravity probably explain differences in acclimation of lower and upper body blood flow to HDT and actual microgravity.

  6. Correlations between corneal and optic nerve head variables in healthy subjects and patients with primary open angle glaucoma

    PubMed Central

    Saenz-Frances, Federico; Jañez, Luis; Borrego-Sanz, Lara; Berrozpe-Villabona, Clara; Martinez-de-la-Casa, Jose Maria; Morales-Fernandez, Laura; Garcia-Sanchez, Julian; Santos-Bueso, Enrique; Garcia-Feijoo, Julian

    2015-01-01

    AIM To correlate corneal variables (determined using the Pentacam) with optic nerve head (ONH) variables determined using the Heidelberg retina tomograph (HRT) in healthy subjects and patients diagnosed with primary open angle glaucoma (POAG). METHODS Measurements were made in 75 healthy eyes and 73 eyes with POAG and correlations examined through Pearson correlation coefficients between the two sets of variables in the two subject groups. The corneal variables determined were corneal volume (CVol), central corneal thickness (CCT), overall corneal thickness (OvCT), the mean thickness of a circular zone centered at the corneal apex of 1 mm radius (zone I) and the mean thickness of several concentric rings, also centered at the apex until the limbus, each of 1 mm width (zones II to VI respectively). The ONH variables were determined using the HRT. RESULTS The following pairs of variables were correlated in the control group: CCT-disc area (DAr) (-0.48; P<0.0001), Zone I-DAr (-0.503; P<0.0001) and Zone II-DAr (-0.443; P<0.0001); and in the POAG group: CCT-cup-to-disc area ratio (CDRa) (-0.402; P<0.0001), Zone I-CDRa (-0.418; P<0.0001), Zone II-CDRa (-0.405; P=0.006), Zone I-cup shape measure (CSM) (-0.415; P=0.002), Zone II-CSM (-0.405; P=0.001), Zone IV-height variation contour (HVC) (0.378; P=0.002); Zone V-HVC (0.388, P<0.0001). CONCLUSIONS In the healthy subjects, significant negative correlation was detected between central and paracentral corneal thickness and optic disc area. In contrast, the POAG patients showed significant negative correlation between central and paracentral corneal thickness and the cup-disc ratio and CSM, and positive correlation between peripheral corneal thickness and HVC. PMID:26682165

  7. Optic nerve head parameters of high-definition optical coherence tomography and Heidelberg retina tomogram in perimetric and preperimetric glaucoma

    PubMed Central

    Begum, Viquar Unnisa; Addepalli, Uday Kumar; Senthil, Sirisha; Garudadri, Chandra Sekhar; Rao, Harsha Laxmana

    2016-01-01

    Background: Heidelberg retina tomogram (HRT) and optical coherence tomography (OCT) are two widely used imaging modalities to evaluate the optic nerve head (ONH) in glaucoma. Purpose: To compare the ONH parameters of HRT3 and high-definition OCT (HD-OCT) and evaluate their diagnostic abilities in perimetric and preperimetric glaucoma. Design: Cross-sectional analysis. Methods: 35 control eyes (24 subjects), 21 preperimetric glaucoma eyes (15 patients), and 64 perimetric glaucoma eyes (44 patients) from the Longitudinal Glaucoma Evaluation Study underwent HRT3 and HD-OCT examinations. Statistical Analysis: Agreement between the ONH parameters of HRT and HD-OCT were assessed using Bland-Altman plots. Diagnostic abilities of ONH parameters were evaluated using area under the receiver operating characteristic curves (AUCs), sensitivity at fixed specificity, and likelihood ratios (LR). Results: Optic disc area, vertical cup to disc ratio, and cup volume with HD-OCT were larger than with HRT, while the rim area was smaller with HD-OCT (P < 0.001 for all comparisons). AUCs of all HD-OCT ONH parameters (0.90-0.97 in perimetric and 0.62-0.71 in preperimetric glaucoma) were comparable (P > 0.10) to the corresponding HRT ONH parameters (0.81-0.95 in perimetric and 0.55-0.72 in preperimetric glaucoma). LRs associated with diagnostic categorization of ONH parameters of both HD-OCT and HRT were associated with larger effects on posttest probability of perimetric compared to preperimetric glaucoma. Conclusions: ONH measurements of HD-OCT and HRT3 cannot be used interchangeably. Though the diagnostic abilities of ONH parameters of HD-OCT and HRT in glaucoma were comparable, the same were significantly lower in preperimetric compared to perimetric glaucoma. PMID:27221679

  8. Early detection of glaucoma using fully automated disparity analysis of the optic nerve head (ONH) from stereo fundus images

    NASA Astrophysics Data System (ADS)

    Sharma, Archie; Corona, Enrique; Mitra, Sunanda; Nutter, Brian S.

    2006-03-01

    Early detection of structural damage to the optic nerve head (ONH) is critical in diagnosis of glaucoma, because such glaucomatous damage precedes clinically identifiable visual loss. Early detection of glaucoma can prevent progression of the disease and consequent loss of vision. Traditional early detection techniques involve observing changes in the ONH through an ophthalmoscope. Stereo fundus photography is also routinely used to detect subtle changes in the ONH. However, clinical evaluation of stereo fundus photographs suffers from inter- and intra-subject variability. Even the Heidelberg Retina Tomograph (HRT) has not been found to be sufficiently sensitive for early detection. A semi-automated algorithm for quantitative representation of the optic disc and cup contours by computing accumulated disparities in the disc and cup regions from stereo fundus image pairs has already been developed using advanced digital image analysis methodologies. A 3-D visualization of the disc and cup is achieved assuming camera geometry. High correlation among computer-generated and manually segmented cup to disc ratios in a longitudinal study involving 159 stereo fundus image pairs has already been demonstrated. However, clinical usefulness of the proposed technique can only be tested by a fully automated algorithm. In this paper, we present a fully automated algorithm for segmentation of optic cup and disc contours from corresponding stereo disparity information. Because this technique does not involve human intervention, it eliminates subjective variability encountered in currently used clinical methods and provides ophthalmologists with a cost-effective and quantitative method for detection of ONH structural damage for early detection of glaucoma.

  9. A Framework for Detecting Glaucomatous Progression in the Optic Nerve Head of an Eye using Proper Orthogonal Decomposition

    PubMed Central

    Balasubramanian, Madhusudhanan; Žabić, Stanislav; Bowd, Christopher; Thompson, Hilary W.; Wolenski, Peter; Iyengar, S. Sitharama; Karki, Bijaya B.; Zangwill, Linda M.

    2009-01-01

    Glaucoma is the second leading cause of blindness worldwide. Often the optic nerve head (ONH) glaucomatous damage and ONH changes occur prior to visual field loss and are observable in vivo. Thus, digital image analysis is a promising choice for detecting the onset and/or progression of glaucoma. In this work, we present a new framework for detecting glaucomatous changes in the ONH of an eye using the method of proper orthogonal decomposition (POD). A baseline topograph subspace was constructed for each eye to describe the structure of the ONH of the eye at a reference/baseline condition using POD. Any glaucomatous changes in the ONH of the eye present during a follow-up exam were estimated by comparing the follow-up ONH topography with its baseline topograph subspace representation. Image correspondence measures of L1 and L2 norms, correlation, and image Euclidean distance (IMED) were used to quantify the ONH changes. An ONH topographic library built from the Louisiana State University Experimental Glaucoma study was used to evaluate the performance of the proposed method. The area under the receiver operating characteristic curves (AUC) were used to compare the diagnostic performance of the POD induced parameters with the parameters of Topographic Change Analysis (TCA) method. The IMED and L2 norm parameters in the POD framework provided the highest AUC of 0.94 at 10° field of imaging and 0.91 at 15° field of imaging compared to the TCA parameters with an AUC of 0.86 and 0.88 respectively. The proposed POD framework captures the instrument measurement variability and inherent structure variability and shows promise for improving our ability to detect glaucomatous change over time in glaucoma management. PMID:19369163

  10. From Clinical Examination of the Optic Disc to Clinical Assessment of the Optic Nerve Head: A Paradigm Change

    PubMed Central

    Chauhan, Balwantray C.; Burgoyne, Claude F.

    2013-01-01

    Purpose To review and interpret optic nerve head (ONH) anatomy detected with spectral domain optical coherence tomography (SD-OCT) pertaining to the clinical examination of the optic disc and propose that a paradigm change for clinical assessment of the ONH is necessary. Design Perspective. Methods Presently, the clinician evaluates neuroretinal rim health according to the appearance of the optic disc, the clinically visible surface of the ONH. Recent anatomic findings with SD-OCT have challenged the basis and accuracy of current rim evaluation. We demonstrate why incorporation of SD-OCT imaging of the ONH into the clinical examination of the disc is required. Results Disc margin based rim evaluation lacks a solid anatomic basis and results in variably inaccurate measurements for two reasons. First, the clinically visible disc margin is an unreliable outer border of rim tissue due to clinically and photographically invisible extensions of Bruch’s membrane. Second, rim tissue orientation is not considered in width measurements. We propose alternative anatomically and geometrically accurate SD-OCT based approaches for rim assessment that have enhanced detection of glaucoma. We also argue for new data acquisition and analysis strategies with SD-OCT that account for the large inter-individual variability in the angle between the fovea and ONH. Conclusions We propose a 4-point paradigm change for clinical assessment of the ONH that is anchored to the eye-specific anatomy and geometry of the ONH and fovea. Our approach is designed to enhance the accuracy and consistency of rim width, as well as peripapillary and macular intraretinal thickness measurements. PMID:23768651

  11. Role of endothelin-A receptors in optic nerve head red cell flux regulation during isometric exercise in healthy humans.

    PubMed

    Boltz, Agnes; Schmidl, Doreen; Werkmeister, René M; Lasta, Michael; Kaya, Semira; Palkovits, Stefan; Told, Reinhard; Frantal, Sophie; Garhöfer, Gerhard; Schmetterer, Leopold

    2013-01-01

    Endothelin-1 (ET-1) is an important regulator of vascular tone in the eye. It appears to play a role in ocular disease because of its strong vasoconstrictor action, its role in intraocular pressure homeostasis, and its neurotoxic potential. We have previously shown that ET-1 is involved in choroidal red cell flux (RCF) regulation during isometric exercise in healthy humans. In the present study we hypothesized that ET-1 also plays a role in optic nerve head (ONH) RCF regulation during isometric exercise. To test this hypothesis, we performed a randomized, double-masked, placebo-controlled, two-way crossover study in 15 healthy volunteers. Subjects were randomized to receive intravenous infusions of the specific endothelin type A receptor antagonist BQ-123 and placebo on two different study days. During these infusion periods, subjects performed squatting for 6 min to increase ocular perfusion pressure (OPP). ONH RCF was assessed with laser-Doppler flowmetry, and OPP was calculated from mean arterial pressure and intraocular pressure. BQ-123 did not change OPP or ONH RCF at baseline. The relative increase in OPP during isometric exercise was comparable between both groups (between 84 and 88%, P = 0.76 between groups; P < 0.001 vs. baseline). Isometric exercise increased ONH RCF during placebo and BQ-123, but the increase was more pronounced when the endothelin type-A receptor antagonist was administered (placebo, 27.3 ± 5.4%; and BQ-123, 39.2 ± 4.4%; P = 0.007 between groups). The present data indicate that ET-1 regulates red cell flux in the ONH beyond the autoregulatory range. PMID:23103498

  12. Traumatic Brain Injury by a Closed Head Injury Device Induces Cerebral Blood Flow Changes and Microhemorrhages

    PubMed Central

    Kallakuri, Srinivasu; Bandaru, Sharath; Zakaria, Nisrine; Shen, Yimin; Kou, Zhifeng; Zhang, Liying; Haacke, Ewart Mark; Cavanaugh, John M

    2015-01-01

    Objectives: Traumatic brain injury is a poly-pathology characterized by changes in the cerebral blood flow, inflammation, diffuse axonal, cellular, and vascular injuries. However, studies related to understanding the temporal changes in the cerebral blood flow following traumatic brain injury extending to sub-acute periods are limited. In addition, knowledge related to microhemorrhages, such as their detection, localization, and temporal progression, is important in the evaluation of traumatic brain injury. Materials and Methods: Cerebral blood flow changes and microhemorrhages in male Sprague Dawley rats at 4 h, 24 h, 3 days, and 7 days were assessed following a closed head injury induced by the Marmarou impact acceleration device (2 m height, 450 g brass weight). Cerebral blood flow was measured by arterial spin labeling. Microhemorrhages were assessed by susceptibility-weighted imaging and Prussian blue histology. Results: Traumatic brain injury rats showed reduced regional and global cerebral blood flow at 4 h and 7 days post-injury. Injured rats showed hemorrhagic lesions in the cortex, corpus callosum, hippocampus, and brainstem in susceptibility-weighted imaging. Injured rats also showed Prussian blue reaction products in both the white and gray matter regions up to 7 days after the injury. These lesions were observed in various areas of the cortex, corpus callosum, hippocampus, thalamus, and midbrain. Conclusions: These results suggest that changes in cerebral blood flow and hemorrhagic lesions can persist for sub-acute periods after the initial traumatic insult in an animal model. In addition, microhemorrhages otherwise not seen by susceptibility-weighted imaging are present in diverse regions of the brain. The combination of altered cerebral blood flow and microhemorrhages can potentially be a source of secondary injury changes following traumatic brain injury and may need to be taken into consideration in the long-term care of these cases. PMID:26605126

  13. Effect of selective vagal nerve stimulation on blood pressure, heart rate and respiratory rate in rats under metoprolol medication.

    PubMed

    Gierthmuehlen, Mortimer; Plachta, Dennis T T

    2016-02-01

    Selective vagal nerve stimulation (sVNS) has been shown to reduce blood pressure without major side effects in rats. This technology might be the key to non-medical antihypertensive treatment in patients with therapy-resistant hypertension. β-blockers are the first-line therapy of hypertension and have in general a bradycardic effect. As VNS itself can also promote bradycardia, it was the aim of this study to investigate the influence of the β1-selective blocker Metoprolol on the effect of sVNS especially with respect to the heart rate. In 10 male Wistar rats, a polyimide multichannel-cuff electrode was placed around the vagal nerve bundle to selectively stimulate the aortic depressor nerve fibers. The stimulation parameters were adapted to the thresholds of individual animals and were in the following ranges: frequency 30-50 Hz, amplitude 0.3-1.8 mA and pulse width 0.3-1.3 ms. Blood pressure responses were detected with a microtip transducer in the carotid artery, and electrocardiography was recorded with s.c. chest electrodes. After IV administration of Metoprolol (2 mg kg(-1) body weight), the animals' mean arterial blood pressure (MAP) and heart rate (HR) decreased significantly. Although the selective electrical stimulation of the baroreceptive fibers reduced MAP and HR, both effects were significantly alleviated by Metoprolol. As a side effect, the rate of stimulation-induced apnea significantly increased after Metoprolol administration. sVNS can lower the MAP under Metoprolol without causing severe bradycardia. PMID:26581776

  14. Microscopy and Microanalysis of Blood in a Snake Head Fish, Channa gachua Exposed to Environmental Pollution.

    PubMed

    Pala, Eva M; Dey, Sudip

    2016-02-01

    Conventional and highly sophisticated analytical methods (Cyria et al., 1989; Massar et al., 2012a) were used to analyze micro-structural and micro-analytical aspects of the blood of snake head fish, Channa gachua, exposed to municipal wastes and city garbage. Red (RBC) and white blood cell (WBC) counts and hemhemoglobin content were found to be higher in pollution affected fish as compared with control. Scanning electron microscopy revealed the occurrence of abnormal erythrocytes such as crenated cells, echinocytes, lobopodial projections, membrane internalization, spherocytes, ruptured cells, contracted cells, depression, and uneven elongation of erythrocyte membranes in fish inhabiting the polluted sites. Energy-dispersive X-ray spectroscopy (EDS) revealed the presence of silicon and lead in the RBCs of pollution affected fish. Significance of the study includes the highly sophisticated analytical approach, which revealed the aforementioned micro-structural abnormalities. PMID:26914995

  15. Simulated Microgravity Increases Cutaneous Blood Flow in the Head and Leg of Humans

    NASA Technical Reports Server (NTRS)

    Stout, M. Shannon; Watenpaugh, Donald E.; Breit, Gregory A.; Hargens, Alan R.

    1995-01-01

    The cutaneous microcirculation vasodilates during acute 6 degree head-down tilt (HDT, simulated microgravity) relative to upright conditions, more in the lower body than in the upper body. Cutaneous microvascular blood flow was measured with laser-Doppler flowmetry at the leg (over the distal tibia) and cheek (over the zygomatic arch) of eight healthy men before, during, and after 24 h of HDT. Results were calculated as a percentage of baseline value (100% measured during pre-tilt upright sitting). Cutaneous blood flow in the cheek increased significantly to 165 +/- 37% (mean +/- SE, p less than 0.05) at 9-12 h HDT, then returned to near baseline values by 24 h HDT (114 +/- 29%, NSD), despite increased local arterial pressure. Microvascular flow in the leg remained significantly elevated above baseline througout 24 h HDT (427 +/- 85% at 3 h HDT and 215 +/- 142% at 24 h HDT, p less than 0.05). During the 6-h upright sitting recovery period, cheek and leg blood flow levels returned to near pre-tilt baseline values. Because hydrostatic effects of HDT increase local arterial pressure at the carotid sinus, baroreflex-mediated withdrawal of sympathetic tone probably contributed to increased microvascular flows at the head and leg during HDT. In the leg baroreflex effects combined with minimal stimulation of local veno-arteriolar and myogenic autoregulatory vasoconstriction to elicit relatively larger and more sustained increases in cutaneous flow during HDT. In the cheek, delayed myogenic vasoconstriction and/or hurmonal effects apparently compensated for flow elevation by 24 h of HDT. Therefore, localized vascular adaptations to gravity probably explain differences in acclimation of lower and upper body blood flow to HDT and actual microgravity.

  16. Facial nerve paralysis and partial brachial plexopathy after epidural blood patch: a case report and review of the literature

    PubMed Central

    Shahien, Radi; Bowirrat, Abdalla

    2011-01-01

    We report a complication related to epidural analgesia for delivery in a 24- year-old woman who was admitted with mild pre-eclampsia and for induction of labor. At the first postpartum day she developed a postdural puncture headache, which was unresponsive to conservative measures. On the fifth day an epidural blood patch was done, and her headache subsided. Sixteen hours later she developed paralysis of the right facial nerve, which was treated with prednisone. Seven days later she complained of pain in the left arm and the posterior region of the shoulder. She was later admitted and diagnosed with partial brachial plexopathy. PMID:21386953

  17. Head Lice

    MedlinePlus

    Head lice are parasitic wingless insects. They live on people's heads and feed on their blood. An adult louse ... Children ages 3-11 and their families get head lice most often. Personal hygiene has nothing to ...

  18. Head Lice

    MedlinePlus

    Head lice are parasitic wingless insects. They live on people's heads and feed on their blood. An adult ... Children ages 3-11 and their families get head lice most often. Personal hygiene has nothing to do ...

  19. Head Injuries

    MedlinePlus

    ... injuries internal head injuries, which may involve the skull, the blood vessels within the skull, or the brain Fortunately, most childhood falls or ... knock the brain into the side of the skull or tear blood vessels. Some internal head injuries ...

  20. Mechanosensitive release of ATP through pannexin channels and mechanosensitive upregulation of pannexin channels in optic nerve head astrocytes: a mechanism for purinergic involvement in chronic strain

    PubMed Central

    Beckel, Jonathan M.; Argall, Arthur J.; Lim, Jason C.; Xia, Jingsheng; Lu, Wennan; Coffey, Erin E.; Macarak, Edward J.; Shahidullah, Mohammed; Delamere, Nicholas A.; Zode, Gulab S.; Sheffield, Val C.; Shestopalov, Valery I.; Laties, Alan M.; Mitchell, Claire H.

    2014-01-01

    As ATP released from astrocytes can modulate many neural signaling systems, the triggers of and pathways for this ATP release are important. Here, the ability of mechanical strain to trigger ATP release through pannexin channels, and the effects of sustained strain on pannexin expression, were examined in rat optic nerve head astrocytes. Astrocytes released ATP when subjected to 5% equibiaxial strain or to hypotonic swelling. While astrocytes expressed mRNA for pannexins 1–3, connexin 43 and VNUT, pharmacological analysis suggested a predominant role for pannexins in mechanosensitive ATP release, with Rho kinases contributing. Astrocytes from panx1−/− mice had reduced baseline and stimulated levels of extracellular ATP, confirming the role for pannexins. Swelling astrocytes triggered a regulatory volume decrease that was inhibited by apyrase or probenecid. The swelling–induced rise in calcium was inhibited by P2X7 receptor antagonists A438079 and AZ10606120, in addition to apyrase and carbenoxelone. Extended stretch of astrocytes in vitro upregulated expression of panx1 and panx2 mRNA. A similar upregulation was observed in vivo in optic nerve head tissue from the Tg-MYOCY437H mouse model of chronic glaucoma; genes for panx1, panx2 and panx3 were increased while immunohistochemistry confirmed increased expression of pannexin 1 protein. In summary, astrocytes released ATP in response to mechanical strain, with pannexin 1 the predominant efflux pathway. Sustained strain upregulated pannexins in vitro and in vivo. Together these findings provide a mechanism by which extracellular ATP remains elevated under chronic mechanical strain, as found in the optic nerve head of patients with glaucoma. PMID:24839011

  1. Magnetic Resonance Imaging of Blood Brain/Nerve Barrier Dysfunction and Leukocyte Infiltration: Closely Related or Discordant?

    PubMed Central

    Weise, Gesa; Stoll, Guido

    2012-01-01

    Unlike other organs the nervous system is secluded from the rest of the organism by the blood brain barrier (BBB) or blood nerve barrier (BNB) preventing passive influx of fluids from the circulation. Similarly, leukocyte entry to the nervous system is tightly controlled. Breakdown of these barriers and cellular inflammation are hallmarks of inflammatory as well as ischemic neurological diseases and thus represent potential therapeutic targets. The spatiotemporal relationship between BBB/BNB disruption and leukocyte infiltration has been a matter of debate. We here review contrast-enhanced magnetic resonance imaging (MRI) as a non-invasive tool to depict barrier dysfunction and its relation to macrophage infiltration in the central and peripheral nervous system under pathological conditions. Novel experimental contrast agents like Gadofluorine M (Gf) allow more sensitive assessment of BBB dysfunction than conventional Gadolinium (Gd)-DTPA enhanced MRI. In addition, Gf facilitates visualization of functional and transient alterations of the BBB remote from lesions. Cellular contrast agents such as superparamagnetic iron oxide particles (SPIO) and perfluorocarbons enable assessment of leukocyte (mainly macrophage) infiltration by MR technology. Combined use of these MR contrast agents disclosed that leukocytes can enter the nervous system independent from a disturbance of the BBB, and vice versa, a dysfunctional BBB/BNB by itself is not sufficient to attract inflammatory cells from the circulation. We will illustrate these basic imaging findings in animal models of multiple sclerosis, cerebral ischemia, and traumatic nerve injury and review corresponding findings in patients. PMID:23267343

  2. 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.

  3. BMI, HOMA-IR, and Fasting Blood Glucose Are Significant Predictors of Peripheral Nerve Dysfunction in Adult Overweight and Obese Nondiabetic Nepalese Individuals: A Study from Central Nepal

    PubMed Central

    Thapa, Lekhjung; Rana, P. V. S.

    2016-01-01

    Objective. Nondiabetic obese individuals have subclinical involvement of peripheral nerves. We report the factors predicting peripheral nerve function in overweight and obese nondiabetic Nepalese individuals. Methodology. In this cross-sectional study, we included 50 adult overweight and obese nondiabetic volunteers without features of peripheral neuropathy and 50 healthy volunteers to determine the normative nerve conduction data. In cases of abnormal function, the study population was classified on the basis of the number of nerves involved, namely, “<2” or “≥2.” Multivariable logistic regression analysis was carried out to predict outcomes. Results. Fasting blood glucose (FBG) was the significant predictor of motor nerve dysfunction (P = 0.039, 95% confidence interval (CI) = 1.003–1.127). Homeostatic model assessment of insulin resistance (HOMA-IR) was the significant predictor (P = 0.019, 96% CI = 1.420–49.322) of sensory nerve dysfunction. Body mass index (BMI) was the significant predictor (P = 0.034, 95% CI = 1.018–1.577) in case of ≥2 mixed nerves' involvement. Conclusion. FBG, HOMA-IR, and BMI were significant predictors of peripheral nerve dysfunction in overweight and obese Nepalese individuals. PMID:27200189

  4. BMI, HOMA-IR, and Fasting Blood Glucose Are Significant Predictors of Peripheral Nerve Dysfunction in Adult Overweight and Obese Nondiabetic Nepalese Individuals: A Study from Central Nepal.

    PubMed

    Thapa, Lekhjung; Rana, P V S

    2016-01-01

    Objective. Nondiabetic obese individuals have subclinical involvement of peripheral nerves. We report the factors predicting peripheral nerve function in overweight and obese nondiabetic Nepalese individuals. Methodology. In this cross-sectional study, we included 50 adult overweight and obese nondiabetic volunteers without features of peripheral neuropathy and 50 healthy volunteers to determine the normative nerve conduction data. In cases of abnormal function, the study population was classified on the basis of the number of nerves involved, namely, "<2" or "≥2." Multivariable logistic regression analysis was carried out to predict outcomes. Results. Fasting blood glucose (FBG) was the significant predictor of motor nerve dysfunction (P = 0.039, 95% confidence interval (CI) = 1.003-1.127). Homeostatic model assessment of insulin resistance (HOMA-IR) was the significant predictor (P = 0.019, 96% CI = 1.420-49.322) of sensory nerve dysfunction. Body mass index (BMI) was the significant predictor (P = 0.034, 95% CI = 1.018-1.577) in case of ≥2 mixed nerves' involvement. Conclusion. FBG, HOMA-IR, and BMI were significant predictors of peripheral nerve dysfunction in overweight and obese Nepalese individuals. PMID:27200189

  5. Blood supply of the olfactory nerve. Meningeal relationships and surgical relevance.

    PubMed

    Favre, J J; Chaffanjon, P; Passagia, J G; Chirossel, J P

    1995-01-01

    The authors report the results of a series of dissections and anatomic sections of the fronto-basal region of the brain and of the anterior cranial fossa in human cadavers. The constant presence of an arachnoidal cistern above the olfactory nerve was verified. The arachnoid separates from the pial membrane and forms a bridge with the ventral part of the olfactory bulb and tract, from the lateral edge of the olfactory sulcus to the medial edge of the gyrus rectus. The cistern is wide in its anterior portion, between the gyrus rectus and the olfactory bulb, and is reduced to a virtual slit in its posterior portion where the tract is lodged in the olfactory sulcus. The olfactory nerve can be separated without damaging fronto-basal arachnoidial adhesions over several centimeters. Dissection of this region after intravascular injection of colored media shows the constant presence of an artery destined to the olfactory bulb and tract. It originates either from the lateral surface of the anterior cerebral a. (segment A2), or from the medial fronto-basal a., and consistently provides terminal branches in front of the olfactory trigone in the medial olfactory sulcus. At their ventral extremity, the olfactory structures are therefore vascularised independently for several centimeters, from the lower face of the frontal lobe. The independent vascularisation of the olfactory nerve, the tenuous and easily detachable adhesions, and the actual presence of a true arachnoidal cistern all contribute to enabling surgical techniques which conserve olfactory function during anterior approaches. PMID:7482150

  6. Spatiotemporal characteristics of cerebral blood volume changes in different microvascular compartments evoked by sciatic nerve stimulation in rat somatosensory cortex

    NASA Astrophysics Data System (ADS)

    Li, Pengcheng; Luo, Qingming; Luo, Weihua; Chen, Shanbin; Cheng, Haiying; Zeng, Shaoqun

    2003-07-01

    The spatio-temporal characteristics of changes in cerebral blood volume associated with neuronal activity were investigated in the hindlimb somatosensory cortex of α-chloralose/urethan anesthetized rats (n=10) with optical imaging at 570nm through a thinned skull. Activation of cortex was carried out by electrical stimulation of the contralateral sciatic nerve with 5Hz, 0.3V pulses (0.5ms) for duration of 2s. The stimulation evoked a monophasic optical reflectance decrease at cortical parenchyma and arteries sites rapidly after the onset of stimulation, whereas no similar response was observed at vein compartments. The optical signal changes reached 10% of the peak response 0.70+/-0.32s after stimulation onset and no significant time lag in this 10% start latency time was observed between the response at cortical parenchyma and arteries compartments. The evoked optical reflectance decrease reached the peak (0.25%+/-0.047%) 2.66+/-0.61s after the stimulus onset at parenchyma site, 0.40+/-0.20s earlier (P<0.05) than that at arteries site (0.50+/-0.068% 3.06+/-0.70s). Variable location within the cortical parenchyma and arteries compartment themselves didn"t affect the temporal characteristics of the evoked signal significantly. These results suggest that the sciatic nerve stimulation evokes a local blood volume increase at both capillaries (cortical parenchyma) and arterioles rapidly after the stimulus onset but the evoked blood volume increase in capillaries could not be entirely accounted for by the dilation of arterioles.

  7. Enhanced Stability of Blood Matrices Using a Dried Sample Spot Assay to Measure Human Butyrylcholinesterase Activity and Nerve Agent Adducts

    PubMed Central

    Perez, Jonas W.; Pantazides, Brooke G.; Watson, Caroline M.; Thomas, Jerry D.; Blake, Thomas A.; Johnson, Rudolph C.

    2015-01-01

    Dried matrix spots are safer to handle and easier to store than wet blood products, but factors such as intra-spot variability and unknown sample volumes have limited their appeal as a sampling format for quantitative analyses. In this work, we introduce a dried spot activity assay for quantifying butyrylcholinesterase (BChE) specific activity which is BChE activity normalized to the total protein content in a sample spot. The method was demonstrated with blood, serum, and plasma spotted on specimen collection devices (cards) which were extracted to measure total protein and BChE activity using a modified Ellman assay. Activity recovered from dried spots was ∼80% of the initial spotted activity for blood and >90% for plasma and serum. Measuring total protein in the sample and calculating specific activity substantially improved quantification and reduced intra-spot variability. Analyte stability of nerve agent adducts was also evaluated, and the results obtained via BChE-specific activity measurements were confirmed by quantification of BChE adducts using a previously established LC-MS/MS method. The spotted samples were up to 10-times more resistant to degradation compared to unspotted control samples when measuring BChE inhibition by the nerve agents sarin and VX. Using this method, both BChE activity and adducts can be accurately measured from a dried sample spot. This use of a dried sample spot with normalization to total protein is robust, demonstrates decreased intra-spot variability without the need to control for initial sample volume, and enhances analyte stability. PMID:25955132

  8. Comparative survival study of glial cells and cells composing walls of blood vessels in crustacean ventral nerve cord after photodynamic treatment

    NASA Astrophysics Data System (ADS)

    Kolosov, Mikhail S.; Shubina, Elena

    2015-03-01

    Photodynamic therapy is a prospective treatment modality of brain cancers. It is of importance to have information about relative survival rate of different cell types in nerve tissue during photodynamic treatment. Particularly, for development of sparing strategy of the photodynamic therapy of brain tumors, which pursuits both total elimination of malignant cells, which are usually of glial origin, and, at the same time, preservation of normal blood circulation as well as normal glial cells in the brain. The aim of this work was to carry out comparative survival study of glial cells and cells composing walls of blood vessels after photodynamic treatment, using simple model object - ventral nerve cord of crustacean.

  9. A 10-minute point-of-care assay for detection of blood protein adducts resulting from low level exposure to organophosphate nerve agents.

    PubMed

    VanDine, Robert; Babu, Uma Mahesh; Condon, Peter; Mendez, Arlene; Sambursky, Robert

    2013-03-25

    The OrganoTox test is a rapid, point-of-care assay capable of detecting clinically relevant organophosphate (OP) poisoning after low-level exposure to sarin, soman, tabun, or VX chemical nerve agents. The test utilizes either a finger stick peripheral blood sample or plasma specimen. While high-level nerve agent exposure can quickly lead to death, low-level exposure produces vague, nondescript signs and symptoms that are not easily clinically differentiated from other conditions. In initial testing, the OrganoTox test was used to detect the presence of blood protein-nerve agent adducts in exposed blood samples. In order to mimic the in vivo exposure as closely as possible, nerve agents stored in organic solvents were spiked in minute quantities into whole blood samples. For performance testing, 40 plasma samples were spiked with sarin, soman, tabun, or VX and 10 normal plasma samples were used as the negative control. The 40 nerve agent-spiked plasma samples included 10 replicates of each agent. At the clinically relevant low-level exposure of 10 ng/ml, the OrganoTox test demonstrated 100% sensitivity for soman, tabun, and VX and 80% sensitivity for sarin. The OrganoTox test demonstrated greater than 97% specificity with 150 blood samples obtained from healthy adults. No cross-reactivity or interference from pesticide precursor compounds was found. A rapid test for nerve agent exposure will help identify affected patients earlier in the clinical course and trigger more appropriate medical management in a more timely manner. PMID:23200942

  10. [The response of the blood proteins to ablation of the capsaicin-sensitive nerves].

    PubMed

    Kostina, N E; Spiridonov, V K

    2005-07-01

    Effects of neurotoxic doses of capsaicin (150 mg/kg) on the protein content in electrophoretic fractions (PAAG) in the Wistar rat plasma were studied. In early period (7 days) after administration of capsaicin, an increase of the alpha1-, alpha2-globulins and a decrease of the albumin, gamma-globulins, were observed. After 14-30 days, increase of the albumin and decrease of the alpha1-, gammay-globulins were detected. The ablation of the capsaicin-sensitive nerves abrogated the changes of positive and negative acute phase reactants induced by zymosan and diminished the content of gamma-globulins. PMID:16206619

  11. Expression of Glucose Transporters in the Prelaminar Region of the Optic-Nerve Head of the Pig as Determined by Immunolabeling and Tissue Culture

    PubMed Central

    Carreras, F. Javier; Aranda, Carlos J.; Porcel, David; Rodriguez-Hurtado, Francisco; Martínez-Agustin, Olga; Zarzuelo, Antonio

    2015-01-01

    Background To develop the use of cultured tissue of the prelaminar optic nerve of the pig to explore possible alterations of the astrocyte-axon metabolic pathways in glaucoma, we map the distribution of the glucose transporters GLUT1 and GLUT3 in fresh and cultured tissue. Methods We monitor cell survival in cultures of the prelaminar optic-nerve tissue, measuring necrosis and apoptosis markers biochemically as well as morphologically, and establish the presence of the glucose transporters GLUT1 and GLUT3. We map the distribution of these transporters with immunolabeling in histological sections of the optic nerve using confocal and electronic transmission microscopy. Results We find that the main death type in prelaminar culture is apoptosis. Caspase 7 staining reveals an increment in apoptosis from day 1 to day 4 and a reduction from day 4 to day 8. Western blotting for GLUT1 shows stability with increased culture time. CLSM micrographs locate GLUT1 in the columnar astrocytes and in the area of axonal bundles. Anti-GLUT3 predominantly labels axonal bundles. TEM immunolabeling with colloidal gold displays a very specific distribution of GLUT-1 in the membranes of vascular endothelial cells and in periaxonal astrocyte expansions. The GLUT-3 isoform is observed with TEM only in axons in the axonal bundles. Conclusions Tissue culture is suitable for apoptosis-induction experiments. The results suggest that glucose is transported to the axonal cleft intracytoplasmically and delivered to the cleft by GLUT1 transporters. As monocarboxylate transporters have been reported in the prelaminar region of the optic-nerve head, this area is likely to use both lactate and glucose as energy sources. PMID:26030125

  12. Fiber-optic immuno-biosensor for rapid and accurate detection of nerve growth factor in human blood.

    PubMed

    Tang, Liang; Cha, Yong-Mei; Li, Hongmei; Chen, Peng-Sheng; Lin, Shien-Fong

    2006-01-01

    An accurate and rapid assay of cardiac nerve growth factor (NGF) levels in blood can provide physicians with critical information regarding myocardial injury and neural remodeling in cardiac tissues to identify patients at risk of impending heart attack, thereby enabling them to receive appropriate lifesaving treatment more quickly. Currently used assay methods, such as enzyme-linked immunosorbent assay (ELISA), are usually time-consuming (hours to days), expensive and technically complicated. In this paper, we described the development and clinical study of a rapid and sensitive method for detection and quantification of NGF in human blood plasma. This method utilizes a fiber-optic, immuno-biosensing system which performs a fluorophore-mediated sandwich immunoassay on the surface of an optical fiber. Physiological concentrations of NGF could be quantified in both buffer and human blood plasma samples within 5 minutes. The NGF concentrations determined by the fiberoptic sensor were comparable to those by the gold standard, ELISA. Preliminary study of NGF assay in cardiac patient plasma samples showed a great potential of the fiber-optic sensor as a rapid diagnostic and prognostic tool in clinical applications. PMID:17946002

  13. Sex differences in blood pressure control during 6° head-down tilt bed rest

    PubMed Central

    Arzeno, Natalia M.; Lee, Stuart M. C.; Ploutz-Snyder, Robert; Platts, Steven H.

    2013-01-01

    Spaceflight-induced orthostatic intolerance has been studied for decades. Although ∼22% of the astronaut corps are women, most mechanistic studies use mostly male subjects, despite known sex differences in autonomic control and postflight orthostatic intolerance. We studied adrenergic, baroreflex, and autonomic indexes during continuous infusions of vasoactive drugs in men and women during a 60-day head-down bed rest. Volunteers were tested before bed rest (20 men and 10 women) and around day 30 (20 men and 10 women) and day 60 (16 men and 8 women) of bed rest. Three increasing doses of phenylephrine (PE) and sodium nitroprusside were infused for 10 min after an infusion of normal saline. A 20-min rest period separated the phenylephrine and sodium nitroprusside infusions. Autonomic activity was approximated by spectral indexes of heart rate and blood pressure variability, and baroreflex sensitivity was measured by the spontaneous baroreflex slope. Parasympathetic modulation and baroreflex sensitivity decreased with bed rest, with women experiencing a larger decrease in baroreflex sensitivity by day 30 than men. The sympathetic activation of men and parasympathetic responsiveness of women in blood pressure control during physiological stress were preserved throughout bed rest. During PE infusions, women experienced saturation of the R-R interval at high frequency, whereas men did not, revealing a sex difference in the parabolic relationship between high-frequency R-R interval, a measurement of respiratory sinus arrhythmia, and R-R interval. These sex differences in blood pressure control during simulated microgravity reveal the need to study sex differences in long-duration spaceflight to ensure the health and safety of the entire astronaut corps. PMID:23396455

  14. Influence of age on respiratory modulation of muscle sympathetic nerve activity, blood pressure and baroreflex function in humans

    PubMed Central

    Shantsila, Alena; McIntyre, David B.; Lip, Gregory Y. H.; Fadel, Paul J.; Paton, Julian F. R.; Pickering, Anthony E.

    2015-01-01

    New Findings What is the central question of this study? Does ageing influence the respiratory‐related bursting of muscle sympathetic nerve activity (MSNA) and the association between the rhythmic fluctuations in MSNA and blood pressure (Traube–Hering waves) that occur with respiration? What is the main finding and its importance? Despite the age‐related elevation in MSNA, the cyclical inhibition of MSNA during respiration is similar between young and older individuals. Furthermore, central respiratory–sympathetic coupling plays a role in the generation of Traube–Hering waves in both young and older humans. Healthy ageing and alterations in respiratory–sympathetic coupling have been independently linked with heightened sympathetic neural vasoconstrictor activity. We investigated how age influences the respiratory‐related modulation of muscle sympathetic nerve activity (MSNA) and the association between the rhythmic fluctuations in MSNA and blood pressure that occur with respiration (Traube–Hering waves; THW). Ten young (22 ± 2 years; mean ± SD) and 10 older healthy men (58 ± 6 years) were studied while resting supine and breathing spontaneously. MSNA, blood pressure and respiration were recorded simultaneously. Resting values were ascertained and respiratory cycle‐triggered averaging of MSNA and blood pressure measurements performed. The MSNA burst incidence was higher in older individuals [22.7 ± 9.2 versus 42.2 ± 13.7 bursts (100 heart beats)−1, P < 0.05], and was reduced to a similar extent in the inspiratory to postinspiratory period in young and older subjects (by ∼25% compared with mid‐ to late expiration). A similar attenuation of MSNA burst frequency (in bursts per minute), amplitude and total activity (burst frequency × mean burst amplitude) was also observed in the inspiratory to postinspiratory period in both groups. A significant positive correlation between respiratory‐related MSNA and the magnitude of

  15. Blood pressure is maintained during dehydration by hypothalamic paraventricular nucleus-driven tonic sympathetic nerve activity

    PubMed Central

    Holbein, Walter W; Bardgett, Megan E; Toney, Glenn M

    2014-01-01

    Resting sympathetic nerve activity (SNA) consists primarily of respiratory and cardiac rhythmic bursts of action potentials. During homeostatic challenges such as dehydration, the hypothalamic paraventricular nucleus (PVN) is activated and drives SNA in support of arterial pressure (AP). Given that PVN neurones project to brainstem cardio-respiratory regions that generate bursting patterns of SNA, we sought to determine the contribution of PVN to support of rhythmic bursting of SNA during dehydration and to elucidate which bursts dominantly contribute to maintenance of AP. Euhydrated (EH) and dehydrated (DH) (48 h water deprived) rats were anaesthetized, bilaterally vagotomized and underwent acute PVN inhibition by bilateral injection of the GABA-A receptor agonist muscimol (0.1 nmol in 50 nl). Consistent with previous studies, muscimol had no effect in EH rats (n = 6), but reduced mean AP (MAP; P < 0.001) and integrated splanchnic SNA (sSNA; P < 0.001) in DH rats (n = 6). Arterial pulse pressure was unaffected in both groups. Muscimol reduced burst frequency of phrenic nerve activity (P < 0.05) equally in both groups without affecting the burst amplitude–duration integral (i.e. area under the curve). PVN inhibition did not affect the amplitude of the inspiratory peak, expiratory trough or expiratory peak of sSNA in either group, but reduced cardiac rhythmic sSNA in DH rats only (P < 0.001). The latter was largely reversed by inflating an aortic cuff to restore MAP (n = 5), suggesting that the muscimol-induced reduction of cardiac rhythmic sSNA in DH rats was an indirect effect of reducing MAP and thus arterial baroreceptor input. We conclude that MAP is largely maintained in anaesthetized DH rats by a PVN-driven component of sSNA that is neither respiratory nor cardiac rhythmic. PMID:24973410

  16. UK-414,495, a selective inhibitor of neutral endopeptidase, potentiates pelvic nerve-stimulated increases in female genital blood flow in the anaesthetized rabbit

    PubMed Central

    Wayman, CP; Baxter, D; Turner, L; Van Der Graaf, PH; Naylor, AM

    2010-01-01

    Background and purpose: Female sexual arousal consists of a number of physiological responses resulting from increased genital blood. Vasoactive intestinal peptide (VIP), neuropeptide Y and to a lesser extent nitric oxide are neurotransmitters found in the vasculature of the genitalia. Neutral endopeptidase (NEP) modulates the activity of neuropeptides including VIP. The aim of this study was to investigate the control of genital blood flow by VIP and endogenous neuropeptides using a selective NEP inhibitor [UK-414,495, ((R)-2-({1-[(5-ethyl-1,3,4-thiadiazol-2-yl) carbamoyl]cyclopentyl}methyl) valeric acid)]. Experimental approach: Vaginal and clitoral blood flow (VBF and CBF) were monitored using laser Doppler in terminally anaesthetized New Zealand rabbits. Increases in VBF and CBF were induced by either electrical stimulation of the pelvic nerve or by i.v. infusion of VIP. Key results: Stimulation of the pelvic nerve increased VBF and CBF, compared with basal flow. Increases were mimicked by infusion of exogenous VIP. UK-414,495 dose-dependently potentiated pelvic nerve-stimulated increases in VBF (EC50= 37 ± 9 nM; 3.6 × IC50 rabbit NEP). Nerve-stimulated increases in VBF and CBF were both enhanced after UK-414,495. UK-414,495 increased the amplitude and duration of VIP-induced increases in VBF. UK-414,495 had no effect on basal VBF or cardiovascular parameters. Conclusions and implications: Inhibition of NEP potentiates pelvic nerve-stimulated increases in genital blood flow. This suggests that the endogenous neurotransmitter mediating genital blood flow is a substrate for NEP (most likely VIP). NEP inhibitors may restore sexual arousal in women adversely affected by female sexual arousal disorder. This article is commented on by Angulo, pp. 48–50 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2010.00693.x PMID:20412068

  17. Study on the Dynamic Compound Structure Composed of Mast Cells, Blood Vessels, and Nerves in Rat Acupoint

    PubMed Central

    Mingfu, Luo; Xiaotong, Dong; Xiaojing, Song; Jin, Jiang; Jinling, Zhann; Ying, Han

    2013-01-01

    Background. Circulation system, immunity system, and nervous system have a close relationship with meridian phenomen. However, there is still lack of the results of dynamic changes of these structures in acupoint. The aim of this study is to explore the interrelationship by composite staining techniques. Methodology/Principal Findings. Twenty rats were separated into electroacupuncture group (EA) and control group (Con) randomly. In EA group, the Zusanli and Weishu were stimulated with the 0.1 mA for 25 min. The tissue of these acupoints was double-stained with acetylcholinesterase and Toluidine blue. The compound structure of mast cells, nervous fibers, and mast cells in the acupoint was observed. Conclusions/Significance. The blood vessels, mast cells and acetylcholinesterase responded nerves were clearly observed in acupoint tissues. EA can result in the mast cell recruitment and migration along the blood vessels and nervous bundle, which conformed the dynamic compound structure and played important roles in acupuncture. PMID:23878591

  18. Altered Blood Biomarker Profiles in Athletes with a History of Repetitive Head Impacts.

    PubMed

    Di Battista, Alex P; Rhind, Shawn G; Richards, Doug; Churchill, Nathan; Baker, Andrew J; Hutchison, Michael G

    2016-01-01

    The long-term health effects of concussion and sub-concussive impacts in sport are unknown. Growing evidence suggests both inflammation and neurodegeneration are pivotal to secondary injury processes and the etiology of neurodegenerative diseases. In the present study we characterized circulating brain injury and inflammatory mediators in healthy male and female athletes according to concussion history and collision sport participation. Eighty-seven university level athletes (male, n = 60; female, n = 27) were recruited before the start of the competitive season. Athletes were healthy at the time of the study (no medications, illness, concussion or musculoskeletal injuries). Dependent variables included 29 inflammatory and 10 neurological injury analytes assessed in the peripheral blood by immunoassay. Biomarkers were statistically evaluated using partial least squares multivariate analysis to identify possible relationships to self-reported previous concussion history, number of previous concussions and collision sport participation in male and female athletes. Multiple concussions were associated with increases in peripheral MCP-1 in females, and MCP-4 in males. Collision sport participation was associated with increases in tau levels in males. These results are consistent with previous experimental and clinical findings that suggest ongoing inflammatory and cerebral injury processes after repetitive mild head trauma. However, further validation is needed to correlate systemic biomarkers to repetitive brain impacts, as opposed to the extracranial effects common to an athletic population such as exercise and muscle damage. PMID:27458972

  19. Analysis of pressure head-flow loops of pulsatile rotodynamic blood pumps.

    PubMed

    Jahren, Silje E; Ochsner, Gregor; Shu, Fangjun; Amacher, Raffael; Antaki, James F; Vandenberghe, Stijn

    2014-04-01

    The clinical importance of pulsatility is a recurring topic of debate in mechanical circulatory support. Lack of pulsatility has been identified as a possible factor responsible for adverse events and has also demonstrated a role in myocardial perfusion and cardiac recovery. A commonly used method for restoring pulsatility with rotodynamic blood pumps (RBPs) is to modulate the speed profile, synchronized to the cardiac cycle. This introduces additional parameters that influence the (un)loading of the heart, including the timing (phase shift) between the native cardiac cycle and the pump pulses, and the amplitude of speed modulation. In this study, the impact of these parameters upon the heart-RBP interaction was examined in terms of the pressure head-flow (HQ) diagram. The measurements were conducted using a rotodynamic Deltastream DP2 pump in a validated hybrid mock circulation with baroreflex function. The pump was operated with a sinusoidal speed profile, synchronized to the native cardiac cycle. The simulated ventriculo-aortic cannulation showed that the level of (un)loading and the shape of the HQ loops strongly depend on the phase shift. The HQ loops displayed characteristic shapes depending on the phase shift. Increased contribution of native contraction (increased ventricular stroke work [WS ]) resulted in a broadening of the loops. It was found that the previously described linear relationship between WS and the area of the HQ loop for constant pump speeds becomes a family of linear relationships, whose slope depends on the phase shift. PMID:23889536

  20. Altered Blood Biomarker Profiles in Athletes with a History of Repetitive Head Impacts

    PubMed Central

    2016-01-01

    The long-term health effects of concussion and sub-concussive impacts in sport are unknown. Growing evidence suggests both inflammation and neurodegeneration are pivotal to secondary injury processes and the etiology of neurodegenerative diseases. In the present study we characterized circulating brain injury and inflammatory mediators in healthy male and female athletes according to concussion history and collision sport participation. Eighty-seven university level athletes (male, n = 60; female, n = 27) were recruited before the start of the competitive season. Athletes were healthy at the time of the study (no medications, illness, concussion or musculoskeletal injuries). Dependent variables included 29 inflammatory and 10 neurological injury analytes assessed in the peripheral blood by immunoassay. Biomarkers were statistically evaluated using partial least squares multivariate analysis to identify possible relationships to self-reported previous concussion history, number of previous concussions and collision sport participation in male and female athletes. Multiple concussions were associated with increases in peripheral MCP-1 in females, and MCP-4 in males. Collision sport participation was associated with increases in tau levels in males. These results are consistent with previous experimental and clinical findings that suggest ongoing inflammatory and cerebral injury processes after repetitive mild head trauma. However, further validation is needed to correlate systemic biomarkers to repetitive brain impacts, as opposed to the extracranial effects common to an athletic population such as exercise and muscle damage. PMID:27458972

  1. Noncontact diffuse optical assessment of blood flow changes in head and neck free tissue transfer flaps

    PubMed Central

    Huang, Chong; Radabaugh, Jeffrey P.; Aouad, Rony K.; Lin, Yu; Gal, Thomas J.; Patel, Amit B.; Valentino, Joseph; Shang, Yu; Yu, Guoqiang

    2015-01-01

    Abstract. Knowledge of tissue blood flow (BF) changes after free tissue transfer may enable surgeons to predict the failure of flap thrombosis at an early stage. This study used our recently developed noncontact diffuse correlation spectroscopy to monitor dynamic BF changes in free flaps without getting in contact with the targeted tissue. Eight free flaps were elevated in patients with head and neck cancer; one of the flaps failed. Multiple BF measurements probing the transferred tissue were performed during and post the surgical operation. Postoperative BF values were normalized to the intraoperative baselines (assigning “1”) for the calculation of relative BF change (rBF). The rBF changes over the seven successful flaps were 1.89±0.15, 2.26±0.13, and 2.43±0.13 (mean±standard error), respectively, on postoperative days 2, 4, and 7. These postoperative values were significantly higher than the intraoperative baseline values (p<0.001), indicating a gradual recovery of flap vascularity after the tissue transfer. By contrast, rBF changes observed from the unsuccessful flaps were 1.14 and 1.34, respectively, on postoperative days 2 and 4, indicating less flow recovery. Measurement of BF recovery after flap anastomosis holds the potential to act early to salvage ischemic flaps. PMID:26187444

  2. Cerebral blood flow velocity in humans exposed to 24 h of head-down tilt

    NASA Technical Reports Server (NTRS)

    Kawai, Y.; Murthy, G.; Watenpaugh, D. E.; Breit, G. A.; Deroshia, C. W.; Hargens, A. R.

    1993-01-01

    This study investigates cerebral blood flow (CBF) velocity in humans before, during, and after 24 h of 6 deg head-down tilt (HDT), which is a currently accepted experimental model to simulate microgravity. CBF velocity was measured by use of the transcranial Doppler technique in the right middle cerebral artery of eight healthy male subjects. Mean CBF velocity increased from the pre-HDT upright seated baseline value of 55.5 +/- 3.7 (SE) cm/s to 61.5 +/- 3.3 cm/s at 0.5 h of HDT, reached a peak value of 63.2 +/- 4.1 cm/s at 3 h of HDT, and remained significantly above the pre-HDT baseline for over 6 h of HDT. During upright seated recovery, mean CBF velocity decreased to 87 percent of the pre-HDT baseline value. Mean CBF velocity correlated well with calculated intracranial arterial pressure (IAP). As analyzed by linear regression, mean CBF velocity = 29.6 + 0.32IAP. These results suggest that HDT increases CBF velocity by increasing IAP during several hours after the onset of microgravity. Importantly, the decrease in CBF velocity after HDT may be responsible, in part, for the increased risk of syncope observed in subjects after prolonged bed rest and also in astronauts returning to Earth.

  3. [Joint and sensory branch block of the obturator and femoral nerves in a case of femoral head osteonecrosis and arthritis].

    PubMed

    Cortiñas-Sáenz, M; Salmerón-Velez, G; Holgado-Macho, I A

    2014-01-01

    The sensory innervation of the hip joint is complex. The joint and sensory branch block of the obturator and femoral nerves is effective for treating the pain caused due to different hip diseases. This could be an option to be considered in certain circumstances such as, being a surgical-anaesthetic high risk, or if there is significant overweight, It could also be useful on other occasions if the traumatoligist considers that it is better to delay hip replacement for a limited period. PMID:24656423

  4. Head injury. Second edition

    SciTech Connect

    Cooper, P.R.

    1987-01-01

    This book contains 22 chapters. Some of the chapter titles are: Radiographic Evaluation; Epidemiology of Head Injury; Emergency Care and Initial Evaluation; Skull Fracture and Traumatic Cerebrospinal Fluid Fistulas; Mild Head Injury; and Injuries of the Cranial Nerves.

  5. Cerebral blood flow, arteriovenous oxygen difference, and outcome in head injured patients.

    PubMed Central

    Robertson, C S; Contant, C F; Gokaslan, Z L; Narayan, R K; Grossman, R G

    1992-01-01

    Cerebral blood flow (CBF) and other physiological variables were measured repeatedly for up to 10 days after severe head injury in 102 patients, and CBF levels were related to outcome. Twenty five of the patients had a reduced CBF [mean (SD) 0.29 (0.05) ml/g/min]; 47 had a normal CBF, (0.41 (0.10) ml/g/min); and 30 had a raised CBF (0.62 (0.14) ml/g/min). Cerebral arteriovenous oxygen differences were inversely related to CBF and averaged 2.1 (0.7) mumol/ml in the group with reduced CBF, 1.9 (0.5) mumol/ml in the group with normal CBF, and 1.6 (0.4) mumol/ml in the group with raised CBF. Patients with a reduced CBF had a poorer outcome than patients with a normal or raised CBF. Mortality was highest in patients with a reduced CBF, and was 32% at three months after injury, whereas only 21% of the patients with a normal CBF and 20% of the patients with a raised CBF died. There were no differences in the type of injury, initial score on the Glasgow Coma Scale, mean intracranial pressure (ICP), highest ICP, or the amount of medical treatment required to keep the ICP less than 20 mm Hg in each group. Systemic factors did not significantly contribute to the differences in CBF among the three groups. A logistic regression model of the effect of CBF on neurological outcome was developed. When adjusted for variables which were found to be significant confounders, including age, initial Glasgow Coma Score, haemoglobin concentration, cerebral perfusion pressure and cerebral metabolic rate of oxygen, a reduced CBF remained significantly associated with an unfavourable neurological outcome. PMID:1640238

  6. Skeletal muscle fiber, nerve, and blood vessel breakdown in space-flown rats

    NASA Technical Reports Server (NTRS)

    Riley, D. A.; Ilyina-Kakueva, E. I.; Ellis, S.; Bain, J. L.; Slocum, G. R.; Sedlak, F. R.

    1990-01-01

    Histochemical and ultrastructural analyses were performed postflight on hind limb skeletal muscles of rats orbited for 12.5 days aboard the unmanned Cosmos 1887 biosatellite and returned to Earth 2 days before sacrifice. The antigravity adductor longus (AL), soleus, and plantaris muscles atrophied more than the non-weight-bearing extensor digitorum longus, and slow muscle fibers were more atrophic than fast fibers. Muscle fiber segmental necrosis occurred selectively in the AL and soleus muscles; primarily, macrophages and neutrophils infiltrated and phagocytosed cellular debris. Granule-rich mast cells were diminished in flight AL muscles compared with controls, indicating the mast cell secretion contributed to interstitial tissue edema. Increased ubiquitination of disrupted myofibrils implicated ubiquitin in myofilament degradation. Mitochondrial content and succinic dehydrogenase activity were normal, except for subsarcolemmal decreases. Myofibrillar ATPase activity of flight AL muscle fibers shifted toward the fast type. Absence of capillaries and extravasation of red blood cells indicated failed microcirculation. Muscle fiber regeneration from activated satellite cells was detected. About 17% of the flight AL end plates exhibited total or partial denervation. Thus, skeletal muscle weakness associated with spaceflight can result from muscle fiber atrophy and segmental necrosis, partial motor denervation, and disruption of the microcirculation.

  7. Structural and Functional Abnormalities of Retinal Ganglion Cells Measured In Vivo at the Onset of Optic Nerve Head Surface Change in Experimental Glaucoma

    PubMed Central

    Fortune, Brad; Burgoyne, Claude F.; Cull, Grant A.; Reynaud, Juan; Wang, Lin

    2012-01-01

    Purpose. To compare peripapillary retinal nerve fiber layer thickness (RNFLT), RNFL retardance, and retinal function at the onset of optic nerve head (ONH) surface topography change in experimental glaucoma (EG). Methods. Thirty-three rhesus macaques had three or more weekly baseline measurements in both eyes of ONH surface topography, peripapillary RNFLT, RNFL retardance, and multifocal electroretinography (mfERG). Laser photocoagulation was then applied to the trabecular meshwork of one eye to induce chronic elevation of IOP and weekly recordings continued alternating between ONH surface topography and RNFLT during one week and RNFL retardance and mfERG the next week. Data were pooled for the group at the onset of ONH surface topography change in each EG eye, which was defined as the first date when either the mean position of the disc (MPD) fell below the 95% confidence limit of each eye's individual baseline range and/or when the topographic change analysis (TCA) map was subjectively judged as having demonstrated change, whichever came first. Analysis of variance with post hoc tests corrected for multiple comparisons were used to assess parameter changes. Results. At onset of ONH surface topography change, there was no significant difference for RNFLT versus baseline or fellow control eyes. RNFL retardance and mfERG were significantly reduced in the recordings just prior (median of 9 days) to ONH onset (P < 0.01) and had progressed significantly (P < 0.001) an average of 17 days later (median of 7 days after ONH onset). RNFLT did not exhibit significant thinning until 15 days after onset of ONH surface topography change (P < 0.001). Conclusions. These results support the hypothesis that during the course of glaucomatous neurodegeneration, axonal cytoskeletal and retinal ganglion cell functional abnormalities exist before thinning of peripapillary RNFL axon bundles begins. PMID:22589428

  8. Human umbilical cord blood mononuclear cells and chorionic plate-derived mesenchymal stem cells promote axon survival in a rat model of optic nerve crush injury

    PubMed Central

    CHUNG, SOKJOONG; RHO, SEUNGSOO; KIM, GIJIN; KIM, SO-RA; BAEK, KWANG-HYUN; KANG, MYUNGSEO; LEW, HELEN

    2016-01-01

    The use of mesenchymal stem cells (MSCs) in cell therapy in regenerative medicine has great potential, particularly in the treatment of nerve injury. Umbilical cord blood (UCB) reportedly contains stem cells, which have been widely used as a hematopoietic source and may have therapeutic potential for neurological impairment. Although ongoing research is dedicated to the management of traumatic optic nerve injury using various measures, novel therapeutic strategies based on the complex underlying mechanisms responsible for optic nerve injury, such as inflammation and/or ischemia, are required. In the present study, a rat model of optic nerve crush (ONC) injury was established in order to examine the effects of transplanting human chorionic plate-derived MSCs (CP-MSCs) isolated from the placenta, as well as human UCB mononuclear cells (CB-MNCs) on compressed rat optic nerves. Expression markers for inflammation, apoptosis, and optic nerve regeneration were analyzed, as well as the axon survival rate by direct counting. Increased axon survival rates were observed following the injection of CB-MNCs at at 1 week post-transplantation compared with the controls. The levels of growth-associated protein-43 (GAP-43) were increased after the injection of CB-MNCs or CP-MSCs compared with the controls, and the expression levels of hypoxia-inducible factor-1α (HIF-1α) were also significantly increased following the injection of CB-MNCs or CP-MSCs. ERM-like protein (ERMN) and SLIT-ROBO Rho GTPase activating protein 2 (SRGAP2) were found to be expressed in the optic nerves of the CP-MSC-injected rats with ONC injury. The findings of our study suggest that the administration of CB-MNCs or CP-MSCs may promote axon survival through systemic concomitant mechanisms involving GAP-43 and HIF-1α. Taken together, these findings provide further understanding of the mechanisms repsonsible for optic nerve injury and may aid in the development of novel cell-based therapeutic strategies with

  9. Analgesic drug delivery via recombinant tissue plasminogen activator and microRNA-183-triggered opening of the blood-nerve barrier.

    PubMed

    Yang, Shaobing; Krug, Susanne M; Heitmann, Johanna; Hu, Liu; Reinhold, Ann Kristin; Sauer, Solange; Bosten, Judith; Sommer, Claudia; Fromm, Michael; Brack, Alexander; Rittner, Heike L

    2016-03-01

    The peripheral nerve contains three barriers which include the blood-nerve barrier consisting of endoneurial vessels and the perineurium as well as autotypic junctions in Schwann cells. The perineurium prevents diffusion of perineurally injected drugs that can be used for selective regional pain control. It is composed of a basal membrane and layers of perineurial cells sealed by tight junction proteins like claudin-1. Claudin-1 expression and barrier function are regulated via low-density lipoprotein receptor-related protein (LRP-1). Perisciatic application of recombinant tissue plasminogen activator (rtPA) or the catalytically inactive rtPAi - both agonists of LRP-1 - reduced claudin-1 mRNA and protein expression in the rat nerve. This facilitated an increase of nociceptive thresholds after local application of hydrophilic opioids or the voltage gated sodium channel blocker (NaV1.7) ProToxin-II without apparent nerve toxicity. RtPA-induced barrier opening was mediated by LRP-1 and intracellularly by Erk phosphorylation. In silico, microRNA (miR)-rno-29b-2-5p and rno-miR-183-5p were identified as potential regulators of claudin-1 transcription in the rat. RtPA application increased miR-183-5p in the sciatic nerve. MiR-183-5p mimics functionally opened the perineurium and downregulated claudin-1 expression in vivo. In vitro, hsa-miR-183-3p mimics reduced claudin-1 expression in human HT-29/B6 cells. Overall, rtPA regulates perineurial barrier tightness via LRP-1, Erk phosphorylation and miR-183-5p/3p. This mechanism might serve as a new principle to facilitate drug delivery to peripheral nerves in humans. PMID:26735170

  10. The Effect of Ergotamine on Tissue Blood Flow and the Arteriovenous Shunting of Radioactive Microspheres in the Head

    PubMed Central

    Johnston, Barbara M.; Saxena, P.R.

    1978-01-01

    1 The radioactive microsphere method was used to study the effects of ergotamine (5, 10 and 20 μg/kg, i.v.) on systemic and regional haemodynamic variables in chloralose-urethane anaesthetized cats. The influence of the drug was also studied on the number of 15 μm microspheres escaping entrapment in the head to emerge in the left external jugular vein. 2 Ergotamine decreased the heart rate and cardiac output. Since arterial blood pressure remained unchanged, calculated total peripheral resistance increased. 3 The regional distribution of cardiac output obtained with 15 μm microspheres agreed well with previous studies in cats where 25 μm spheres were used. The most pronounced difference was that in the present investigation more microspheres, apparently escaping through arteriovenous anastomoses (AVAs), were detected in the lungs than when larger spheres had been used. 4 Coronary blood flow decreased, while uterine blood flow was increased by the drug. The microsphere content of the lungs, which receive the spheres not only via bronchial arteries but also via AVAs, was greatly reduced by all doses of ergotamine. Ergotamine did not influence tissue blood flow to other major organs such as the brain, kidneys, skin, liver, skeletal muscle or the gastrointestinal tract. 5 In the 16 experiments, 0.46 ± 0.05 (s.e. mean)% of the total microspheres injected (equivalent to 11.7 ± 1.4% of microspheres detected in the left-side of the head) appeared within 2 min of microsphere injection into the left external jugular vein. The highest dose of ergotamine significantly reduced the shunting of the microspheres in the head. 6 Since 15 μm microspheres are only likely to reach the lungs by passing into the venous circulation through large glomus-type AVAs, we conclude that ergotamine reduces the fraction of microspheres appearing in the lungs by causing strong vasoconstriction in the AVAs in the head. 7 In conformity with the closure of head AVAs is the finding that

  11. Longitudinal tracking of muscle sympathetic nerve activity and its relationship with blood pressure in subjects with prehypertension.

    PubMed

    Hering, Dagmara; Kara, Tomas; Kucharska, Wiesława; Somers, Virend K; Narkiewicz, Krzysztof

    2016-06-01

    Prehypertension is associated with increased cardiovascular events. While the "tracking phenomenon" is an important longitudinal characteristic of blood pressure (BP), changes in muscle sympathetic nerve activity (MSNA) over time remain unclear. This study tested the hypothesis that MSNA tracking contributes to BP trends in prehypertension. BP and MSNA were assessed in 13 prehypertensive males at rest, during hand grip and mental stressors at baseline and after 8 years. Baseline office BP averaged 127 ± 2/81 ± 2 mmHg and MSNA 24 ± 4 bursts/min. BP increased by 7 ± 2/5 ± 2 mmHg (P < 0.01) and MSNA by 11 ± 2 bursts/min (P < 0.001) at follow-up. SBP and DBP were interrelated at baseline (r = 0.65, P = 0.02) and at follow-up (r = 0.78, P = 0.002). MSNA tracking (r = 0.82; P < 0.001) was similar to BP. MSNA was strongly related to DBP at baseline (r = 0.73; P < 0.01) and follow-up (r = 0.64; P = 0.01), more so than SBP. BMI increased (P < 0.001) at follow-up but was unrelated to BP or MSNA. Despite comparable pressor and cardiac increases to handgrip and mental stressors, sympathetic responses were blunted, more pronounced to isometric test (P < 0.006) at follow-up. In conclusion, the trend in MSNA corresponds with BP changes over time suggesting that tonic sympathetic activation may contribute to time-related increase in resting BP and the development of sustained hypertension in prehypertension. PMID:26654200

  12. Gastrointestinal Intervention Ameliorates High Blood Pressure Through Antagonizing Overdrive of the Sympathetic Nerve in Hypertensive Patients and Rats

    PubMed Central

    Zhang, Hexuan; Pu, Yunfei; Chen, Jing; Tong, Weidong; Cui, Yuanting; Sun, Fang; Zheng, Zhou; Li, Qiang; Yang, Tao; Meng, Changyuan; Lu, Zongshi; Li, Li; Yan, Zhencheng; Liu, Daoyan; Zhu, Zhiming

    2014-01-01

    Background We investigated the hypothesis that the favorable effects of gastrointestinal (GI) intervention on hypertension (HTN) and cardiovascular (CV) disturbances are mediated by antagonizing overdrive of the sympathetic nervous system (SNS). Methods and Results Hypertensive patients with metabolic disturbances underwent laparoscopic Roux‐en‐Y gastric bypass surgery, and spontaneously hypertensive rats (SHRs) underwent RYGB or sham surgery. Blood pressure (BP), heart rate (HR), endothelium‐dependent flow‐mediated dilation, and anthropometric as well as laboratory parameters were measured at baseline and during follow‐up. Changes of BP and HR in response to cold stress, renal sympathetic nervous activity (RSNA), vasoconstriction induced by electrical field stimulation, microinjection of nucleus of the solitary tract (NTS), and CV function and structure were examined in SHRs with or without surgery. Compared with baseline, BP and HR were significantly reduced in both hypertensive patients with type 2 diabetes and rats. Impaired endothelial‐dependent vasodilatation and metabolic disturbances in hypertensive patients were also ameliorated after surgery. CV disturbances were reversed by surgery in SHRs. Under acute cold exposure, the variations in BP and HR were smaller in surgically treated SHRs, compared to sham SHRs. RSNA and vasoconstriction induced by perivascular nerve stimulation as well as NTS‐mediated changes of BP were decreased in surgically treated SHRs, compared to sham SHR. Weight loss did not affect BP and RSNA in sham SHRs. Conclusions GI intervention ameliorates HTN in both hypertensive patients and rats by inhibiting overdrive of the SNS. Therefore, targeting gastrointestine could be a novel strategy to treat HTN with metabolic disturbances. PMID:25240055

  13. Determination of cup-to-disc ratio of optical nerve head for diagnosis of glaucoma on stereo retinal fundus image pairs

    NASA Astrophysics Data System (ADS)

    Muramatsu, Chisako; Nakagawa, Toshiaki; Sawada, Akira; Hatanaka, Yuji; Hara, Takeshi; Yamamoto, Tetsuya; Fujita, Hiroshi

    2009-02-01

    A large cup-to-disc (C/D) ratio, which is the ratio of the diameter of the depression (cup) to that of the optical nerve head (ONH, disc), can be one of the important signs for diagnosis of glaucoma. Eighty eyes, including 25 eyes with the signs of glaucoma, were imaged by a stereo retinal fundus camera. An ophthalmologist provided the outlines of cup and disc on a regular monitor and on the stereo display. The depth image of the ONH was created by determining the corresponding pixels in a pair of images based on the correlation coefficient in localized regions. The areas of the disc and cup were determined by use of the red component in one of the color images and by use of the depth image, respectively. The C/D ratio was determined based on the largest vertical lengths in the cup and disc areas, which was then compared with that by the ophthalmologist. The disc areas determined by the computerized method agreed relatively well with those determined by the ophthalmologist, whereas the agreement for the cup areas was somewhat lower. When C/D ratios were employed for distinction between the glaucomatous and non-glaucomatous eyes, the area under the receiver operating characteristic curve (AUC) was 0.83. The computerized analysis of ONH can be useful for diagnosis of glaucoma.

  14. Cost-effective instrumentation for quantitative depth measurement of optic nerve head using stereo fundus image pair and image cross correlation techniques

    NASA Astrophysics Data System (ADS)

    de Carvalho, Luis Alberto V.; Carvalho, Valeria

    2014-02-01

    One of the main problems with glaucoma throughout the world is that there are typically no symptoms in the early stages. Many people who have the disease do not know they have it and by the time one finds out, the disease is usually in an advanced stage. Most retinal cameras available in the market today use sophisticated optics and have several other features/capabilities (wide-angle optics, red-free and angiography filters, etc) that make them expensive for the general practice or for screening purposes. Therefore, it is important to develop instrumentation that is fast, effective and economic, in order to reach the mass public in the general eye-care centers. In this work, we have constructed the hardware and software of a cost-effective and non-mydriatic prototype device that allows fast capturing and plotting of high-resolution quantitative 3D images and videos of the optical disc head and neighboring region (30° of field of view). The main application of this device is for glaucoma screening, although it may also be useful for the diagnosis of other pathologies related to the optic nerve.

  15. Pulse-Wave Analysis of Optic Nerve Head Circulation Is Significantly Correlated with Kidney Function in Patients with and without Chronic Kidney Disease

    PubMed Central

    Takahashi, Mao

    2014-01-01

    Aim. To determine whether there is a significant correlation between the optic nerve head (ONH) circulation determined by laser speckle flowgraphy (LSFG) and kidney function. Materials. Seventy-one subjects were investigated. The estimated glomerular filtration rate (GFR) and serum creatinine, cystatin C, and urinary albumin excretion were measured. The ONH circulation was determined by an analysis of the pulse wave of LSFG, and this parameter was named blowout time (BOT). Chronic kidney disease (CKD) was defined to be present when the estimated GFR was <60 mL/min per 1.73 m2. Pearson's correlation coefficients were used to determine the relationship between the BOT and the kidney function. We also examined whether there were significant differences in all parameters in patients with and without CKD. Results. BOT was significantly correlated with the level of creatinine (r = −0.24, P = 0.04), the estimated GFR (r = 0.42, P = 0.0003), cystatin C (r = −0.29, P = 0.01), and urinary albumin excretion (r = −0.29, P = 0.01). The BOT level in subjects with CKD was significantly lower than that in subjects without CKD (P = 0.002). Conclusion. BOT in ONH by LSFG can detect the organ damage such as kidney dysfunction, CKD. PMID:24678413

  16. Pulse-Wave Analysis of Optic Nerve Head Circulation Is Significantly Correlated with Kidney Function in Patients with and without Chronic Kidney Disease.

    PubMed

    Shiba, Tomoaki; Takahashi, Mao; Maeno, Takatoshi

    2014-01-01

    Aim. To determine whether there is a significant correlation between the optic nerve head (ONH) circulation determined by laser speckle flowgraphy (LSFG) and kidney function. Materials. Seventy-one subjects were investigated. The estimated glomerular filtration rate (GFR) and serum creatinine, cystatin C, and urinary albumin excretion were measured. The ONH circulation was determined by an analysis of the pulse wave of LSFG, and this parameter was named blowout time (BOT). Chronic kidney disease (CKD) was defined to be present when the estimated GFR was <60 mL/min per 1.73 m(2). Pearson's correlation coefficients were used to determine the relationship between the BOT and the kidney function. We also examined whether there were significant differences in all parameters in patients with and without CKD. Results. BOT was significantly correlated with the level of creatinine (r = -0.24, P = 0.04), the estimated GFR (r = 0.42, P = 0.0003), cystatin C (r = -0.29, P = 0.01), and urinary albumin excretion (r = -0.29, P = 0.01). The BOT level in subjects with CKD was significantly lower than that in subjects without CKD (P = 0.002). Conclusion. BOT in ONH by LSFG can detect the organ damage such as kidney dysfunction, CKD. PMID:24678413

  17. Analysis of the variation in OCT measurements of a structural bottle neck for eye-brain transfer of visual information from 3D-volumes of the optic nerve head, PIMD-Average [02π

    NASA Astrophysics Data System (ADS)

    Söderberg, Per G.; Malmberg, Filip; Sandberg-Melin, Camilla

    2016-03-01

    The present study aimed to analyze the clinical usefulness of the thinnest cross section of the nerve fibers in the optic nerve head averaged over the circumference of the optic nerve head. 3D volumes of the optic nerve head of the same eye was captured at two different visits spaced in time by 1-4 weeks, in 13 subjects diagnosed with early to moderate glaucoma. At each visit 3 volumes containing the optic nerve head were captured independently with a Topcon OCT- 2000 system. In each volume, the average shortest distance between the inner surface of the retina and the central limit of the pigment epithelium around the optic nerve head circumference, PIMD-Average [02π], was determined semiautomatically. The measurements were analyzed with an analysis of variance for estimation of the variance components for subjects, visits, volumes and semi-automatic measurements of PIMD-Average [0;2π]. It was found that the variance for subjects was on the order of five times the variance for visits, and the variance for visits was on the order of 5 times higher than the variance for volumes. The variance for semi-automatic measurements of PIMD-Average [02π] was 3 orders of magnitude lower than the variance for volumes. A 95 % confidence interval for mean PIMD-Average [02π] was estimated to 1.00 +/-0.13 mm (D.f. = 12). The variance estimates indicate that PIMD-Average [02π] is not suitable for comparison between a onetime estimate in a subject and a population reference interval. Cross-sectional independent group comparisons of PIMD-Average [02π] averaged over subjects will require inconveniently large sample sizes. However, cross-sectional independent group comparison of averages of within subject difference between baseline and follow-up can be made with reasonable sample sizes. Assuming a loss rate of 0.1 PIMD-Average [02π] per year and 4 visits per year it was found that approximately 18 months follow up is required before a significant change of PIMDAverage [02π] can

  18. Blood-Brain Barrier Deterioration and Hippocampal Gene Expression in Polymicrobial Sepsis: An Evaluation of Endothelial MyD88 and the Vagus Nerve.

    PubMed

    Honig, Gerard; Mader, Simone; Chen, Huiyi; Porat, Amit; Ochani, Mahendar; Wang, Ping; Volpe, Bruce T; Diamond, Betty

    2016-01-01

    Systemic infection can initiate or exacerbate central nervous system (CNS) pathology, even in the absence of overt invasion of bacteria into the CNS. Recent epidemiological studies have demonstrated that human survivors of sepsis have an increased risk of long-term neurocognitive decline. There is thus a need for improved understanding of the physiological mechanisms whereby acute sepsis affects the CNS. In particular, MyD88-dependent activation of brain microvascular endothelial cells and a resulting loss of blood-brain barrier integrity have been proposed to play an important role in the effects of systemic inflammation on the CNS. Signaling through the vagus nerve has also been considered to be an important component of CNS responses to systemic infection. Here, we demonstrate that blood-brain barrier permeabilization and hippocampal transcriptional responses during polymicrobial sepsis occur even in the absence of MyD88-dependent signaling in cerebrovascular endothelial cells. We further demonstrate that these transcriptional responses can occur without vagus nerve input. These results suggest that redundant signals mediate CNS responses in sepsis. Either endothelial or vagus nerve activation may be individually sufficient to transmit systemic inflammation to the central nervous system. Transcriptional activation in the forebrain in sepsis may be mediated by MyD88-independent endothelial mechanisms or by non-vagal neuronal pathways. PMID:26790027

  19. Blood-Brain Barrier Deterioration and Hippocampal Gene Expression in Polymicrobial Sepsis: An Evaluation of Endothelial MyD88 and the Vagus Nerve

    PubMed Central

    Honig, Gerard; Mader, Simone; Chen, Huiyi; Porat, Amit; Ochani, Mahendar; Wang, Ping; Volpe, Bruce T.; Diamond, Betty

    2016-01-01

    Systemic infection can initiate or exacerbate central nervous system (CNS) pathology, even in the absence of overt invasion of bacteria into the CNS. Recent epidemiological studies have demonstrated that human survivors of sepsis have an increased risk of long-term neurocognitive decline. There is thus a need for improved understanding of the physiological mechanisms whereby acute sepsis affects the CNS. In particular, MyD88-dependent activation of brain microvascular endothelial cells and a resulting loss of blood-brain barrier integrity have been proposed to play an important role in the effects of systemic inflammation on the CNS. Signaling through the vagus nerve has also been considered to be an important component of CNS responses to systemic infection. Here, we demonstrate that blood-brain barrier permeabilization and hippocampal transcriptional responses during polymicrobial sepsis occur even in the absence of MyD88-dependent signaling in cerebrovascular endothelial cells. We further demonstrate that these transcriptional responses can occur without vagus nerve input. These results suggest that redundant signals mediate CNS responses in sepsis. Either endothelial or vagus nerve activation may be individually sufficient to transmit systemic inflammation to the central nervous system. Transcriptional activation in the forebrain in sepsis may be mediated by MyD88-independent endothelial mechanisms or by non-vagal neuronal pathways. PMID:26790027

  20. The impact of high-frequency magnetic stimulation of peripheral nerves: muscle hardness, venous blood flow, and motor function of upper extremity in healthy subjects.

    PubMed

    Okudera, Yoshihiko; Matsunaga, Toshiki; Sato, Mineyoshi; Chida, Satoaki; Hatakeyama, Kazutoshi; Watanabe, Motoyuki; Shimada, Yoichi

    2015-01-01

    The purpose of this study was to investigate the impact of high-frequency peripheral nerve magnetic stimulation on the upper limb function. Twenty-five healthy adults (16 men and 9 women) participated in this study. The radial nerve of the non-dominant hand was stimulated by high-frequency magnetic stimulation device. A total of 600 impulses were applied at a frequency of 20 Hz and intensity of 1.2 resting motor threshold (rMT). At three time points (before, immediately after, and 15 min after stimulation), muscle hardness of the extensor digitorum muscle on the stimulated side was measured using a mechanical tissue hardness meter and a shear wave imaging device, cephalic venous blood flow on the stimulated side was measured using an ultrasound system, and the Box and Block test (BBT) was performed. Mechanical tissue hardness results did not show any significant differences between before, immediately after, and 15 min after stimulation. Measurements via shear wave imaging showed that muscle hardness significantly decreased both immediately and 15 min after stimulation compared to before stimulation (P < 0.05). Peripheral venous blood flow and BBT score significantly increased both immediately and 15 min after stimulation compared to before stimulation (P < 0.01). High-frequency peripheral nerve magnetic stimulation can achieve effects similar to electrical stimulation in a less invasive manner, and may therefore become an important element in next-generation rehabilitation. PMID:25876657

  1. Morphometric Optic Nerve Head Analysis in Glaucoma Patients: A Comparison between the Simultaneous Nonmydriatic Stereoscopic Fundus Camera (Kowa Nonmyd WX3D) and the Heidelberg Scanning Laser Ophthalmoscope (HRT III).

    PubMed

    Mariacher, Siegfried; Hipp, Stephanie; Wirthky, Robert; Blumenstock, Gunnar; Bartz-Schmidt, Karl-Ulrich; Ziemssen, Focke; Schiefer, Ulrich; Voykov, Bogomil; Januschowski, Kai

    2016-01-01

    Purpose. To investigate the agreement between morphometric optic nerve head parameters assessed with the confocal laser ophthalmoscope HRT III and the stereoscopic fundus camera Kowa nonmyd WX3D retrospectively. Methods. Morphometric optic nerve head parameters of 40 eyes of 40 patients with primary open angle glaucoma were analyzed regarding their vertical cup-to-disc-ratio (CDR). Vertical CDR, disc area, cup volume, rim volume, and maximum cup depth were assessed with both devices by one examiner. Mean bias and limits of agreement (95% CI) were obtained using scatter plots and Bland-Altman analysis. Results. Overall vertical CDR comparison between HRT III and Kowa nonmyd WX3D measurements showed a mean difference (limits of agreement) of -0.06 (-0.36 to 0.24). For the CDR < 0.5 group (n = 24) mean difference in vertical CDR was -0.14 (-0.34 to 0.06) and for the CDR ≥ 0.5 group (n = 16) 0.06 (-0.21 to 0.34). Conclusion. This study showed a good agreement between Kowa nonmyd WX3D and HRT III with regard to widely used optic nerve head parameters in patients with glaucomatous optic neuropathy. However, data from Kowa nonmyd WX3D exhibited the tendency to measure larger CDR values than HRT III in the group with CDR < 0.5 group and lower CDR values in the group with CDR ≥ 0.5. PMID:27313870

  2. Morphometric Optic Nerve Head Analysis in Glaucoma Patients: A Comparison between the Simultaneous Nonmydriatic Stereoscopic Fundus Camera (Kowa Nonmyd WX3D) and the Heidelberg Scanning Laser Ophthalmoscope (HRT III)

    PubMed Central

    Mariacher, Siegfried; Wirthky, Robert; Blumenstock, Gunnar; Bartz-Schmidt, Karl-Ulrich; Ziemssen, Focke; Schiefer, Ulrich; Voykov, Bogomil; Januschowski, Kai

    2016-01-01

    Purpose. To investigate the agreement between morphometric optic nerve head parameters assessed with the confocal laser ophthalmoscope HRT III and the stereoscopic fundus camera Kowa nonmyd WX3D retrospectively. Methods. Morphometric optic nerve head parameters of 40 eyes of 40 patients with primary open angle glaucoma were analyzed regarding their vertical cup-to-disc-ratio (CDR). Vertical CDR, disc area, cup volume, rim volume, and maximum cup depth were assessed with both devices by one examiner. Mean bias and limits of agreement (95% CI) were obtained using scatter plots and Bland-Altman analysis. Results. Overall vertical CDR comparison between HRT III and Kowa nonmyd WX3D measurements showed a mean difference (limits of agreement) of −0.06 (−0.36 to 0.24). For the CDR < 0.5 group (n = 24) mean difference in vertical CDR was −0.14 (−0.34 to 0.06) and for the CDR ≥ 0.5 group (n = 16) 0.06 (−0.21 to 0.34). Conclusion. This study showed a good agreement between Kowa nonmyd WX3D and HRT III with regard to widely used optic nerve head parameters in patients with glaucomatous optic neuropathy. However, data from Kowa nonmyd WX3D exhibited the tendency to measure larger CDR values than HRT III in the group with CDR < 0.5 group and lower CDR values in the group with CDR ≥ 0.5. PMID:27313870

  3. Cross-matched blood for major head and neck surgery: an analysis of requirements.

    PubMed

    Fordyce, A M; Telfer, M R; Stassen, L F

    1998-04-01

    We retrospectively analysed our blood ordering practice; the number of units of cross-matched blood requested was compared with the number transfused, in 70 patients undergoing a total of 82 ablative operations for malignant disease. Patients undergoing neck dissection alone, or excision of tumour with free revascularized flap reconstruction without neck dissection, are unlikely to require blood transfusion. Operations that include excision of tumour with primary closure and neck dissection, excision of tumour with pedicled flap reconstruction and excision of tumour with any form of flap reconstruction and neck dissection in continuity, will probably require transfusion. If atypical antibodies are present in the patient's serum on screening, cross-matched blood should always be available preoperatively. Provided that atypical antibodies are not present and that blood is available within 40 minutes from the blood bank, our results show that it is safe to adopt a policy of blood grouping and saving serum, for patients undergoing neck dissection alone, but cross-matching two or more units of blood for patients who are to have more extensive operations. PMID:9643594

  4. Cerebral blood flow and metabolism in children with severe head injuries. Part 2: Cerebrovascular resistance and its determinants.

    PubMed Central

    Sharples, P M; Matthews, D S; Eyre, J A

    1995-01-01

    It has been proposed that in children with severe head injuries the cerebral circulation does not respond appropriately to normal physiological control mechanisms, making children more susceptible than adults to low cerebrovascular resistance, increased cerebral blood flow (cerebral hyperaemia), and raised intracranial pressure. To investigate this issue, 122 serial measurements of cerebrovascular resistance in 17 children with severe head injuries have been performed and related to cerebral perfusion pressure, arterial CO2 (PaCO2), arterial oxygen content (AO2), and the cerebral metabolic rate of oxygen (CMRO2). Cerebrovascular resistance values (mean (SD) 1.54 (0.61) mm Hg.ml-1.100 g.min) were normal or raised in most cases; 71 values (58%) were within the normal range, 39 (32%) above the upper limit, and only 12 (10%) below the lower limit. There was a significant correlation between cerebral perfusion pressure and cerebrovascular resistance (r = 0.32, p = 0.0003), suggesting preservation of pressure autoregulation. This correlation was absent in four of the five children who died or survived with severe handicap. Analysis by multilevel modelling indicated that, as in normal subjects, CMRO2, CPP, AO2, PaCO2, and cerebrovenous pH were important independent determinants of cerebrovascular resistance. The results indicate that normal cerebrovascular reactivity is often preserved in children with severe head injuries but may be impaired in the most severely injured patients. PMID:7876844

  5. Preclinical Study of Cell Therapy for Osteonecrosis of the Femoral Head with Allogenic Peripheral Blood-Derived Mesenchymal Stem Cells

    PubMed Central

    Fu, Qiang; Tang, Ning-Ning; Zhang, Qian; Liu, Yi; Peng, Jia-Chen; Fang, Ning; Yu, Li-Mei; Liu, Jin-Wei

    2016-01-01

    Purpose To explore the value of transplanting peripheral blood-derived mesenchymal stem cells from allogenic rabbits (rPBMSCs) to treat osteonecrosis of the femoral head (ONFH). Materials and Methods rPBMSCs were separated/cultured from peripheral blood after granulocyte colony-stimulating factor mobilization. Afterwards, mobilized rPBMSCs from a second passage labeled with PKH26 were transplanted into rabbit ONFH models, which were established by liquid nitrogen freezing, to observe the effect of rPBMSCs on ONFH repair. Then, the mRNA expressions of BMP-2 and PPAR-γ in the femoral head were assessed by RT-PCR. Results After mobilization, the cultured rPBMSCs expressed mesenchymal markers of CD90, CD44, CD29, and CD105, but failed to express CD45, CD14, and CD34. The colony forming efficiency of mobilized rPBMSCs ranged from 2.8 to 10.8 per million peripheral mononuclear cells. After local transplantation, survival of the engrafted cells reached at least 8 weeks. Therein, BMP-2 was up-regulated, while PPAR-γ mRNA was down-regulated. Additionally, bone density and bone trabeculae tended to increase gradually. Conclusion We confirmed that local transplantation of rPBMSCs benefits ONFH treatment and that the beneficial effects are related to the up-regulation of BMP-2 expression and the down-regulation of PPAR-γ expression. PMID:27189298

  6. Sympathetic nerve-derived ATP regulates renal medullary vasa recta diameter via pericyte cells: a role for regulating medullary blood flow?

    PubMed

    Crawford, C; Wildman, S S P; Kelly, M C; Kennedy-Lydon, T M; Peppiatt-Wildman, C M

    2013-01-01

    Pericyte cells are now known to be a novel locus of blood flow control, being able to regulate capillary diameter via their unique morphology and expression of contractile proteins. We have previously shown that exogenous ATP causes constriction of vasa recta via renal pericytes, acting at a variety of membrane bound P2 receptors on descending vasa recta (DVR), and therefore may be able to regulate medullary blood flow (MBF). Regulation of MBF is essential for appropriate urine concentration and providing essential oxygen and nutrients to this region of high, and variable, metabolic demand. Various sources of endogenous ATP have been proposed, including from epithelial, endothelial, and red blood cells in response to stimuli such as mechanical stimulation, local acidosis, hypoxia, and exposure to various hormones. Extensive sympathetic innervation of the nephron has previously been shown, however the innervation reported has focused around the proximal and distal tubules, and ascending loop of Henle. We hypothesize that sympathetic nerves are an additional source of ATP acting at renal pericytes and therefore regulate MBF. Using a rat live kidney slice model in combination with video imaging and confocal microscopy techniques we firstly show sympathetic nerves in close proximity to vasa recta pericytes in both the outer and inner medulla. Secondly, we demonstrate pharmacological stimulation of sympathetic nerves in situ (by tyramine) evokes pericyte-mediated vasoconstriction of vasa recta capillaries; inhibited by the application of the P2 receptor antagonist suramin. Lastly, tyramine-evoked vasoconstriction of vasa recta by pericytes is significantly less than ATP-evoked vasoconstriction. Sympathetic innervation may provide an additional level of functional regulation in the renal medulla that is highly localized. It now needs to be determined under which physiological/pathophysiological circumstances that sympathetic innervation of renal pericytes is important

  7. Evaluation of management techniques to conserve water in a mechanical head wash blood removal system.

    PubMed

    Galloway, H O; Deotte, R E; Lawrence, T E

    2013-11-01

    This research objectively evaluated methods to conserve water in a mechanical beef head wash system. Digital images of pre-wash and post-wash beef heads were analyzed to quantify the percentage change in red saturation of the image, which was used as an objective measure of cleanliness. Three types of nozzles (fan, three-hole, venturi) and three water pressures (344, 516, 689kPa) were evaluated in a two-way treatment structure. An interaction (P=0.07) was observed between water pressure and nozzle type; the change in red saturation increased as pressure decreased for fan and three-hole nozzles which contrasted with venturi nozzles. The fan nozzle×516kPa pressure treatment used 25L of water per head washed and was used to evaluate the effect of three water temperatures (15, 38, 57°C). Water temperature did not impact (P=0.21) change in red saturation. Reducing water wastage and minimizing the use of heated water could have positive economic benefits to the beef processor. PMID:23793094

  8. Corneal Segmentation Analysis Increases Glaucoma Diagnostic Ability of Optic Nerve Head Examination, Heidelberg Retina Tomograph's Moorfield's Regression Analysis, and Glaucoma Probability Score

    PubMed Central

    Saenz-Frances, F.; Jañez, L.; Berrozpe-Villabona, C.; Borrego-Sanz, L.; Morales-Fernández, L.; Acebal-Montero, A.; Mendez-Hernandez, C. D.; Martinez-de-la-Casa, J. M.; Santos-Bueso, E.; Garcia-Sanchez, J.; Garcia-Feijoo, J.

    2015-01-01

    Purpose. To study whether a corneal thickness segmentation model, consisting in a central circular zone of 1 mm radius centered at the corneal apex (zone I) and five concentric rings of 1 mm width (moving outwards: zones II to VI), could boost the diagnostic accuracy of Heidelberg Retina Tomograph's (HRT's) MRA and GPS. Material and Methods. Cross-sectional study. 121 healthy volunteers and 125 patients with primary open-angle glaucoma. Six binary multivariate logistic regression models were constructed (MOD-A1, MOD-A2, MOD-B1, MOD-B2, MOD-C1, and MOD-C2). The dependent variable was the presence of glaucoma. In MOD-A1, the predictor was the result (presence of glaucoma) of the analysis of the stereophotography of the optic nerve head (ONH). In MOD-B1 and MOD-C1, the predictor was the result of the MRA and GPS, respectively. In MOD-B2 and MOD-C2, the predictors were the same along with corneal variables: central, overall, and zones I to VI thicknesses. This scheme was reproduced for model MOD-A2 (stereophotography along with corneal variables). Models were compared using the area under the receiver operator characteristic curve (AUC). Results. MOD-A1-AUC: 0.771; MOD-A2-AUC: 0.88; MOD-B1-AUC: 0.736; MOD-B2-AUC: 0.845; MOD-C1-AUC: 0.712; MOD-C2-AUC: 0.838. Conclusion. Corneal thickness variables enhance ONH assessment and HRT's MRA and GPS diagnostic capacity. PMID:26180641

  9. Optic nerve head analyser and Heidelberg retina tomograph: accuracy and reproducibility of topographic measurements in a model eye and in volunteers.

    PubMed Central

    Janknecht, P; Funk, J

    1994-01-01

    The accuracy and reproducibility of the optic nerve head analyser (ONHA) and the Heidelberg retina tomograph (HRT) were compared and the performance of the HRT in measuring fundus elevations was evaluated. The coefficient of variation of three repeated measurements in a model eye and in volunteers and the relative error in a model eye was calculated. With ONHA measurements the pooled coefficient of variation in volunteers was 9.3% in measuring cup areas and 8.4% in measuring the cup volume. In a model eye the pooled coefficient of variation was 7.6% for the parameter 'cup area' and 9.9% for the parameter 'cup volume'. The pooled relative error in the model eye was 6.6% for the parameter 'cup area' and 5.1% for the parameter 'cup volume'. With HRT measurements in volunteers the pooled coefficient of variation of both the parameters 'volume below contour' and 'volume below surface' was 6.9%. In the model eye the pooled coefficient of variation was 2.4% for the 'volume below contour' and 4.1% for the parameter 'volume below surface'. The pooled relative error in the model eye was 11.3% for the 'volume below contour' and 11% for the 'volume below surface'. The pooled relative error in measuring retinal elevations in the model eye was 3.8%. The coefficient of variation was 3.5%. The accuracies of the HRT and ONHA were similar. However, as the ONHA 'cup volume' is unreliable in patients because of the design of the ONHA whereas the HRT volume parameters are reliable it seems reasonable to assume that the HRT is superior to the ONHA. Only the HRT is capable of quantifying retinal elevations. Images PMID:7803352

  10. Calibrated variability of muscle sympathetic nerve activity during graded head-up tilt in humans and its link with noradrenaline data and cardiovascular rhythms.

    PubMed

    Marchi, Andrea; Bari, Vlasta; De Maria, Beatrice; Esler, Murray; Lambert, Elisabeth; Baumert, Mathias; Porta, Alberto

    2016-06-01

    Muscle sympathetic nerve activity (MSNA) variability is traditionally computed through a low-pass filtering procedure that requires normalization. We proposed a new beat-to-beat MSNA variability computation that preserves dimensionality typical of an integrated neural discharge (i.e., bursts per unit of time). The calibrated MSNA (cMSNA) variability technique is contrasted with the traditional uncalibrated MSNA (ucMSNA) version. The powers of cMSNA and ucMSNA variabilities in the low-frequency (LF, from 0.04 to 0.15 Hz) band were computed with those of the heart period (HP) of systolic and diastolic arterial pressure (SAP and DAP, respectively) in seven healthy subjects (age, 20-28 years; median, 22 years; 5 women) during a graded head-up tilt. Subjects were sequentially tilted at 0°, 20°, 30°, 40°, and 60° table inclinations. The LF powers of ucMSNA and HP variabilities were expressed in normalized units (LFnu), whereas all remaining spectral markers were expressed in absolute units. We found that 1) the LF power of cMSNA variability was positively correlated with tilt angle, whereas the LFnu power of the ucMSNA series was uncorrelated; 2) the LF power of cMSNA variability was correlated with LF powers of SAP and DAP, LFnu power of HP and noradrenaline concentration, whereas the relationship of the LFnu power of ucMSNA variability to LF powers of SAP and DAP was weaker and that to LFnu power of HP was absent; and 3) the stronger relationship of cMSNA variability to SAP and DAP spectral markers compared with the ucMSNA series was confirmed individually. The cMSNA variability appears to be more suitable in describing sympathetic control in humans than traditional ucMSNA variability. PMID:27009053

  11. Analysis of Vision Loss Caused by Radiation-Induced Optic Neuropathy After Particle Therapy for Head-and-Neck and Skull-Base Tumors Adjacent to Optic Nerves

    SciTech Connect

    Demizu, Yusuke; Murakami, Masao; Miyawaki, Daisuke; Niwa, Yasue; Akagi, Takashi; Sasaki, Ryohei; Terashima, Kazuki; Suga, Daisaku; Kamae, Isao; Hishikawa, Yoshio

    2009-12-01

    Purpose: To assess the incident rates of vision loss (VL; based on counting fingers or more severe) caused by radiation-induced optic neuropathy (RION) after particle therapy for tumors adjacent to optic nerves (ONs), and to evaluate factors that may contribute to VL. Methods and Materials: From August 2001 to August 2006, 104 patients with head-and-neck or skull-base tumors adjacent to ONs were treated with carbon ion or proton radiotherapy. Among them, 145 ONs of 75 patients were irradiated and followed for greater than 12 months. The incident rate of VL and the prognostic factors for occurrence of VL were evaluated. The late effects of carbon ion and proton beams were compared on the basis of a biologically effective dose at alpha/beta = 3 gray equivalent (GyE{sub 3}). Results: Eight patients (11%) experienced VL resulting from RION. The onset of VL ranged from 17 to 58 months. The median follow-up was 25 months. No significant difference was observed between the carbon ion and proton beam treatment groups. On univariate analysis, age (>60 years), diabetes mellitus, and maximum dose to the ON (>110 GyE{sub 3}) were significant, whereas on multivariate analysis only diabetes mellitus was found to be significant for VL. Conclusions: The time to the onset of VL was highly variable. There was no statistically significant difference between carbon ion and proton beam treatments over the follow-up period. Based on multivariate analysis, diabetes mellitus correlated with the occurrence of VL. A larger study with longer follow-up is warranted.

  12. Binding of catecholamines to connective tissue and the effect upon the responses of blood vessels to noradrenaline and to nerve stimulation

    PubMed Central

    Powis, Garth

    1973-01-01

    1. Quantitative estimates have been made of the binding of catecholamines to purified collagen and elastin, and the factors influencing this binding have been investigated. 2. Collagen shows no specificity towards the binding of either the (-)- or (+)-isomer of adrenaline or noradrenaline, at low concentrations. Elastin binds the (-)-isomer of adrenaline and noradrenaline to twice the extent of the (+)-isomer. 3. Tetracyclines inhibit the binding of catecholamines to collagen and elastin. Oxytetracycline 10-4 M produces a maximum inhibition of the binding of (-)-noradrenaline to collagen of 68·4%. 4. The responses of perfused blood vessels to the administration of pulses of catecholamines or to adrenergic nerve stimulation have been measured. 5. Oxytetracycline (10-4 M) potentiates the amplitude of the response of the rabbit ear artery to noradrenaline and to nerve stimulation, ten- and sixfold respectively. 6. Those preparations with a high content of collagen and elastic tissue, the rabbit ear artery and the rat tail, are more susceptible to the potentiating effects of oxytetracycline than one with a low content, the rat anococcygeus. 7. The results of the study suggest that in tissues with a high content of collagen and elastin, binding to extracellular sites is the major mechanism for terminating the response to noradrenaline or to adrenergic nerve stimulation. PMID:4766218

  13. Effects of Mild Hypercapnia During Head-Down Bed Rest on Ocular Structures, Cerebral Blood Flow, aud Visual Acuity in Healthy Human Subjects

    NASA Technical Reports Server (NTRS)

    Laurie, S. S.; Taibbi, G.; Lee, S. M. C.; Martin, D. S.; Zanello, S.; Ploutz-Snyder, R.; Hu, X.; Stenger, M. B.; Vizzeri, G.

    2014-01-01

    The cephalad fluid shift induced by microgravity has been hypothesized to cause an elevation in intracranial pressure (ICP) and contribute to the development of the Visual Impairment/Intracranial Pressure (VIIP) syndrome, as experienced by some astronauts during long-duration space flight. Elevated ambient partial pressure of carbon dioxide (PCO2) on ISS may also raise ICP and contribute to VIIP development. We seek to determine if the combination of mild CO2 exposure, similar to that occurring on the International Space Station, with the cephalad fluid shift induced by head-down tilt, will induce ophthalmic and cerebral blood flow changes similar to those described in the VIIP syndrome. We hypothesize that mild hypercapnia in the head-down tilt position will increase choroidal blood volume and cerebral blood flow, raise intraocular pressure (IOP), and transiently reduce visual acuity as compared to the seated or the head-down tilt position without elevated CO2, respectively.

  14. Roles for the sympathetic nervous system, renal nerves, and CNS melanocortin-4 receptor in the elevated blood pressure in hyperandrogenemic female rats

    PubMed Central

    Maranon, Rodrigo; Lima, Roberta; Spradley, Frank T.; do Carmo, Jussara M.; Zhang, Howei; Smith, Andrew D.; Bui, Elizabeth; Thomas, R. Lucas; Moulana, Mohadetheh; Hall, John E.; Granger, Joey P.

    2015-01-01

    Women with polycystic ovary syndrome (PCOS) have hyperandrogenemia and increased prevalence of risk factors for cardiovascular disease, including elevated blood pressure. We recently characterized a hyperandrogenemic female rat (HAF) model of PCOS [chronic dihydrotestosterone (DHT) beginning at 4 wk of age] that exhibits similar characteristics as women with PCOS. In the present studies we tested the hypotheses that the elevated blood pressure in HAF rats is mediated in part by sympathetic activation, renal nerves, and melanocortin-4 receptor (MC4R) activation. Adrenergic blockade with terazosin and propranolol or renal denervation reduced mean arterial pressure (MAP by telemetry) in HAF rats but not controls. Hypothalamic MC4R expression was higher in HAF rats than controls, and central nervous system MC4R antagonism with SHU-9119 (1 nmol/h icv) reduced MAP in HAF rats. Taking a genetic approach, MC4R null and wild-type (WT) female rats were treated with DHT or placebo from 5 to 16 wk of age. MC4R null rats were obese and had higher MAP than WT control rats, and while DHT increased MAP in WT controls, DHT failed to further increase MAP in MC4R null rats. These data suggest that increases in MAP with chronic hyperandrogenemia in female rats are due, in part, to activation of the sympathetic nervous system, renal nerves, and MC4R and may provide novel insights into the mechanisms responsible for hypertension in women with hyperandrogenemia such as PCOS. PMID:25695289

  15. Biosignal-based relaxation evaluation of head-care robot.

    PubMed

    Ando, Takeshi; Takeda, Maki; Maruyama, Tomomi; Susuki, Yuto; Hirose, Toshinori; Fujioka, Soichiro; Mizuno, Osamu; Yamada, Kenji; Ohno, Yuko; Yukio, Honda

    2013-01-01

    Such popular head care procedures as shampooing and scalp massages provide physical and mental relaxation. However, they place a big burden such as chapped hands on beauticians and other practitioners. Based on our robot hand technology, we have been developing a head care robot. In this paper, we quantitatively evaluated its relaxation effect using the following biosignals: accelerated plethymography (SDNN, HF/TP, LF/HF), heart rate (HR), blood pressure, salivary amylase (sAA) and peripheral skin temperature (PST). We compared the relaxation of our developed head care robot with the head care provided by nurses. In our experimental result with 54 subjects, the activity of the autonomic nerve system changed before and after head care procedures performed by both a human nurse and our proposed robot. Especially, in the proposed robot, we confirmed significant differences with the procedure performed by our proposed head care robot in five indexes: HF/TP, LF/HF, HR, sAA, and PST. The activity of the sympathetic nerve system decreased, because the values of its indexes significantly decreased: LF/HF, HR, and sAA. On the other hand, the activity of the parasympathetic nerve system increased, because of the increase of its indexes value: HF/TP and PST. Our developed head care robot provided satisfactory relaxation in just five minutes of use. PMID:24111288

  16. Blood

    MedlinePlus

    ... solid part of your blood contains red blood cells, white blood cells, and platelets. Red blood cells (RBC) deliver oxygen from your lungs to your tissues and organs. White blood cells (WBC) fight infection and are part of your ...

  17. Anemia During Sequential Induction Chemotherapy and Chemoradiation for Head and Neck Cancer: The Impact of Blood Transfusion on Treatment Outcome

    SciTech Connect

    Bhide, Shreerang A.; Ahmed, Merina; Rengarajan, Vijayan; Powell, Ceri; Miah, Aisha; Newbold, Kate; Nutting, Christopher M.; Harrington, Kevin J.

    2009-02-01

    Purpose: Sequential treatment (chemotherapy followed by concomitant chemoradiation; CCRT) is increasingly being used for radical treatment of squamous cell cancer of the head and neck (SCCHN), which results in increased myelosuppression. In this study, we review the incidence of anemia and the effect of a policy of hemoglobin (Hb) maintenance by blood transfusion on disease outcomes in these patients. Methods and Materials: Retrospective review of the records of patients with SCCHN treated with sequential CCRT formed the basis of this study. The incidence of anemia and statistics on blood transfusion were documented. For the purpose of outcome analyses, patients were divided into four categories by (1) transfusion status, (2) nadir Hb concentration, (3) number of transfusion episodes, and (4) number of units of blood transfused (NOUT). Data on 3-year locoregional control (LRC), relapse-free survival (RFS), disease-specific survival (DSS), and overall survival (OS) were analyzed. Results: One hundred and sixty-nine patients were identified. The median follow-up was 23.6 months. The RFS (52% vs. 41%, p = 0.03), DSS (71% vs. 66%, p = 0.02), and OS (58% vs. 42% p = 0.005) were significantly better for patients who did not have a transfusion vs. those who did. The LRC, RFS, DSS, and OS were also significantly better for patients with nadir Hb level >12 vs. <12 g/dL and NOUT 1-4 vs. >4. Conclusion: Our study seems to suggest that blood transfusion during radical treatment for SCCHN might be detrimental. Further research should be undertaken into the complex interactions among tumor hypoxia, anemia, and the treatment of anemia before making treatment recommendations.

  18. Genetic comparison of the head of Henri IV and the presumptive blood from Louis XVI (both Kings of France).

    PubMed

    Charlier, Philippe; Olalde, Iñigo; Solé, Neus; Ramírez, Oscar; Babelon, Jean-Pierre; Galland, Bruno; Calafell, Francesc; Lalueza-Fox, Carles

    2013-03-10

    A mummified head was identified in 2010 as belonging to Henri IV, King of France. A putative blood sample from the King Louis XVI preserved into a pyrographically decorated gourd was analyzed in 2011. Both kings are in a direct male-line descent, separated by seven generations. We have retrieved the hypervariable region 1 of the mitochondrial DNA as well as a partial Y-chromosome profile from Henri IV. Five STR loci match the alleles found in Louis XVI, while another locus shows an allele that is just one mutation step apart. Taking into consideration that the partial Y-chromosome profile is extremely rare in modern human databases, we concluded that both males could be paternally related. The likelihood ratio of the two samples belonging to males separated by seven generations (as opposed to unrelated males) was estimated as 246.3, with a 95% confidence interval between 44.2 and 9729. Historically speaking, this forensic DNA data would confirm the identity of the previous Louis XVI sample, and give another positive argument for the authenticity of the head of Henri IV. PMID:23283403

  19. [Interest of S100B protein blood level determination in severe or moderate head injury].

    PubMed

    Bouvier, Damien

    2013-01-01

    S100B, a suffering brain marker, exhibits a different interest in traumatic brain injury (TBI) as the trauma is severe (sTBI) or mild (mTBI). Our works presented for the attribution of the SFBC 2012 price talked about both aspects. Firstly, the extent of S100B elevation has been found to be useful in predicting clinical outcome after sTBI. However, few studies were realized with jugular venous blood samples. After comparing the interest between jugular venous and arterial blood concentrations evaluation of serum S100B protein in patients with sTBI, determination of S100B concentration in jugular blood samples appears to be better than in arterial ones to predict clinical outcome after brain injury. Secondly, it's difficult to determine the indication of cranial computed tomography (CCT) for patients with mTBI. Actually, 90% of patients with mTBI have unnecessary CCT or short hospitalization for observation. Serum concentrations of S100B were found to provide useful information. We have investigated in 2 studies (1 for adult, 1 for children) whether S100B concentrations in patients with mTBI could provide additional information to improve indication of the need for an initial CCT scan or for a short hospitalization. Patients with intracerebral lesions on the CCT scan (CCT+) or with bad clinical evolution were identified with a sensitivity level of 100% and a specificity level of 30%. Adding the measurement of S-100B serum concentration to the clinical decision rules for a CCT scan or hospitalization in patients with mTBI could allow a 30% reduction in scans and in hospitalization for clinical observation. PMID:23587577

  20. Nerve biopsy

    MedlinePlus

    Nerve biopsy may be done to help diagnose: Axon degeneration (destruction of the axon portion of the nerve cell) Damage to the ... Demyelination Inflammation of the nerve Leprosy Loss of axon tissue Metabolic neuropathies Necrotizing vasculitis Sarcoidosis

  1. Pinched Nerve

    MedlinePlus

    ... Enhancing Diversity Find People About NINDS NINDS Pinched Nerve Information Page Table of Contents (click to jump ... being done? Clinical Trials Organizations What is Pinched Nerve? The term "pinched nerve" is a colloquial term ...

  2. Spatio-temporal characteristics of cerebral blood volume changes in different microvascular compartments evoked by sciatic nerve stimulation in rat somatosensory cortex

    NASA Astrophysics Data System (ADS)

    Li, Pengcheng; Luo, Qingming; Luo, Weihua; Chen, Shangbin; Chen, Haiying; Zeng, Shaoqun

    2003-10-01

    The spatio-temporal characteristics of changes in cerebral blood volume associated with neuronal activity were investigated in the hindlimb somatosensory cortex of α-chloralose/urethan anesthetized rats (n=10) with optical imaging at 570nm through a thinned skull. Activation of cortex was carried out by electrical stimulation of the contralateral sciatic nerve with 5Hz, 0.3V pulses (0.5ms) for duration of 2s. The stimulation evoked a monophasic optical reflectance decrease at cortical parenchyma and arteries sites rapidly after the onset of stimulation, whereas no similar response was observed at vein compartments. The optical signal changes reached 10% of the peak response 0.70+/-0.32s after stimulation onset and no significant time lag in this 10% start latency time was observed between the response at cortical parenchyma and arteries compartments. The evoked optical reflectance decrease reached the peak (0.25%+/-0.047%)2.66+/-0.61s after the stimulus onset at parenchyma site, 0.40+/-0.20s earlier (P<0.05) than that at arteries site (0.50%+/-0.068% 3.06+/-0.70s). Variable location within the cortical parenchyma and arteries compartment themselves didn"t affect the temporal characteristics of the evoked signal significantly. These results suggest that the sciatic nerve stimulation evokes a local blood volume increase at both capillaries (cortical parenchyma) and arterioles rapidly after the stimulus onset but the evoked blood volume increase in capillaries could not be entirely accounted for by the dilation of arterioles.

  3. The Activation Pattern of Blood Leukocytes in Head and Neck Squamous Cell Carcinoma Is Correlated to Survival

    PubMed Central

    Millrud, Camilla Rydberg; Månsson Kvarnhammar, Anne; Uddman, Rolf; Björnsson, Sven; Riesbeck, Kristian; Cardell, Lars Olaf

    2012-01-01

    Head and neck squamous cell carcinoma (HNSCC) is known to cause substantial immunosuppression. The present study was designed to characterize blood leukocyte activation in HNSCC and to investigate if the individual activation pattern could be related to tumor progress and survival. The leukocyte activation profile of HNSCC patients and healthy controls was assessed with flow cytometry. HNSCC patients displayed increased numbers of monocytes, neutrophils and total leukocytes as well as an enhanced neutrophil/lymphocyte ratio. In addition, patients had a higher percentage of CD69+, CD71+ and CD98+ T cell subsets and NK cells, and a reduced expression of L-selectin in CD14highCD16+ monocytes and neutrophils, when compared to controls. These changes could be correlated to both tumor burden and spread to lymph nodes. Among the cancer patients an increased neutrophil/lymphocyte ratio, a low neutrophil and CD14high CD16+ monocyte activation state and an elevated CD4/CD8 ratio were related to poor survival. In contrast, a high percentage of CD98+ Th cells appeared to be associated with a better outcome. Taken together, the present data indicate that HNSCC causes activation of blood leukocytes and that the individual activation pattern can be linked to prognosis. PMID:23251433

  4. Head CT scan

    MedlinePlus

    Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial ... or other growth (mass) Cerebral atrophy (loss of brain tissue) ... with the hearing nerve Stroke or transient ischemic attack (TIA)

  5. Image analysis of optic nerve disease.

    PubMed

    Burgoyne, C F

    2004-11-01

    Existing methodologies for imaging the optic nerve head surface topography and measuring the retinal nerve fibre layer thickness include confocal scanning laser ophthalmoscopy (Heidelberg retinal tomograph), optical coherence tomography, and scanning laser polarimetry. For cross-sectional screening of patient populations, all three approaches have achieved sensitivities and specificities within the 60-80th percentile in various studies, with occasional specificities greater than 90% in select populations. Nevertheless, these methods are not likely to provide useful assistance for the experienced examiner at their present level of performance. For longitudinal change detection in individual patients, strategies for clinically specific change detection have been rigorously evaluated for confocal scanning laser tomography only. While these initial studies are encouraging, applying these algorithms in larger numbers of patients is now necessary. Future directions for these technologies are likely to include ultra-high resolution optical coherence tomography, the use of neural network/machine learning classifiers to improve clinical decision-making, and the ability to evaluate the susceptibility of individual optic nerve heads to potential damage from a given level of intraocular pressure or systemic blood pressure. PMID:15534606

  6. HYPOXIC CONDITIONS INDUCE HSP70 PRODUCTION IN THE BLOOD, BRAIN AND HEAD KIDNEY OF JUVENILE NILE TILAPIA OREOCHROMIS NILOTICUS(L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The levels of constitutive and inducible heat shock protein 70 (Hsp70) was measured in blood, brain, liver, muscle and head kidney tissues of juvenile Nile tilapia Oreochromis niloticus (L.), subjected to increasingly severe hypoxic stress (dissolved oxygen ~ 4.9 - 0.1 mg L-1) for 48 h. A highly sig...

  7. The Location of The Inferior and Superior Temporal Blood Vessels and Inter-Individual Variability of The Retinal Nerve Fiber Layer Thickness

    PubMed Central

    Hood, Donald C.; Salant, Jennifer A.; Arthur, Stella N.; Ritch, Robert; Liebmann, Jeffrey M.

    2009-01-01

    Purpose To determine if adjusting for blood vessel location can decrease the inter-subject variability of retinal nerve fiber (RNFL) thickness measured with optical coherence tomography (OCT). Subjects and Methods One eye of 50 individuals with normal vision was tested with OCT and scanning laser polarimetry (SLP). The SLP and OCT RNFL thickness profiles were determined for a peripapillary circle 3.4 mm in diameter. The midpoints between the superior temporal vein and artery (STva) and the inferior temporal vein and artery (ITva) were determined at the location where the vessels cross the 3.4 mm circle. The average OCT and SLP RNFL thicknesses for quadrants and arcuate sectors of the lower and upper optic disc were obtained before and after adjusting for blood vessel location. This adjustment was done by shifting the RNFL profiles based upon the locations of the STva and ITva relative to the mean locations of all 50 individuals. Results Blood vessel locations ranged over 39° (STva) and 33° (ITva) for the 50 eyes. The location of the leading edge of the OCT and SLP profiles was correlated with the location of the blood vessels for both the superior [r=0.72 (OCT) and 0.72(SLP)] and inferior [r=0.34 and 0.43] temporal vessels. However, the variability in the OCT and SLP thickness measurements showed little change due to shifting. After shifting, the difference in the coefficient of variation ranged from −2.1% (shifted less variable) to +1.7% (unshifted less variable). Conclusion The shape of the OCT and SLP RNFL profiles varied systematically with the location of the superior and inferior superior veins and arteries. However, adjusting for the location of these major temporal blood vessels did not decrease the variability for measures of OCT or SLP RNFL thickness. PMID:19661824

  8. A comparison of blood loss during the Halal slaughter of lambs following Traditional Religious Slaughter without stunning, Electric Head-Only Stunning and Post-Cut Electric Head-Only Stunning.

    PubMed

    Khalid, Rizvan; Knowles, Toby G; Wotton, Steve B

    2015-12-01

    Blood lost at exsanguination during the Halal slaughter of lambs was compared between the slaughter methods of Traditional Religious Slaughter without stunning (TRS), Electric Head-Only Stunning (EHOS) and Post-Cut Electric Head-Only Stunning (PCEHOS). Two protocols were examined, Experimental (80 lambs) and Commercial (360 lambs), assessing varying periods of animal orientation during the 4 min bleeding process (upright orientation before vertical hanging). Live-weight, blood weight (Experimental only), carcass weights and by-product weights were recorded. The Experimental protocol highlighted an increase in blood loss at 60s in EHOS and PCEHOS compared to TRS (P<0.001) but by 90 s there was no significant difference. A post-slaughter change in animal orientation from an upright to a vertical hanging position aided the amount of blood loss. The bleeding of lambs is largely completed by 2 min. There were no significant differences (P>0.05) in final blood loss between treatments. This research was undertaken to inform discussion on the merits of different slaughter methods compatible with Halal requirements. PMID:26159062

  9. Validation of the i-STAT and HemoCue systems for the analysis of blood parameters in the bar-headed goose, Anser indicus

    PubMed Central

    Harter, T. S.; Reichert, M.; Brauner, C. J.; Milsom, W. K.

    2015-01-01

    Every year, bar-headed geese (Anser indicus) perform some of the most remarkable trans-Himalayan migrations, and researchers are increasingly interested in understanding the physiology underlying their high-altitude flight performance. A major challenge is generating reliable measurements of blood parameters on wild birds in the field, where established analytical techniques are often not available. Therefore, we validated two commonly used portable clinical analysers (PCAs), the i-STAT and the HemoCue systems, for the analysis of blood parameters in bar-headed geese. The pH, partial pressures of O2 and CO2 (PO2 and PCO2), haemoglobin O2 saturation (sO2), haematocrit (Hct) and haemoglobin concentration [Hb] were simultaneously measured with the two PCA systems (i-STAT for all parameters; HemoCue for [Hb]) and with conventional laboratory techniques over a physiological range of PO2, PCO2 and Hct. Our results indicate that the i-STAT system can generate reliable values on bar-headed goose whole blood pH, PO2, PCO2 and Hct, but we recommend correcting the obtained values using the linear equations determined here for higher accuracy. The i-STAT is probably not able to produce meaningful measurements of sO2 and [Hb] over a range of physiologically relevant environmental conditions. However, we can recommend the use of the HemoCue to measure [Hb] in the bar-headed goose, if results are corrected. We emphasize that the equations that we provide to correct PCA results are applicable only to bar-headed goose whole blood under the conditions that we tested. We encourage researchers to validate i-STAT or HemoCue results thoroughly for their specific study conditions and species in order to yield accurate results. PMID:27293706

  10. Blood

    MedlinePlus

    ... fight infection and are part of your body's defense system. Platelets help blood to clot when you have a cut or wound. Bone marrow, the spongy material inside your bones, makes new blood cells. Blood cells ...

  11. Effect of head-down-tilt bed rest and hypovolemia on dynamic regulation of heart rate and blood pressure

    NASA Technical Reports Server (NTRS)

    Iwasaki, K. I.; Zhang, R.; Zuckerman, J. H.; Pawelczyk, J. A.; Levine, B. D.; Blomqvist, C. G. (Principal Investigator)

    2000-01-01

    Adaptation to head-down-tilt bed rest leads to an apparent abnormality of baroreflex regulation of cardiac period. We hypothesized that this "deconditioning response" could primarily be a result of hypovolemia, rather than a unique adaptation of the autonomic nervous system to bed rest. To test this hypothesis, nine healthy subjects underwent 2 wk of -6 degrees head-down bed rest. One year later, five of these same subjects underwent acute hypovolemia with furosemide to produce the same reductions in plasma volume observed after bed rest. We took advantage of power spectral and transfer function analysis to examine the dynamic relationship between blood pressure (BP) and R-R interval. We found that 1) there were no significant differences between these two interventions with respect to changes in numerous cardiovascular indices, including cardiac filling pressures, arterial pressure, cardiac output, or stroke volume; 2) normalized high-frequency (0.15-0.25 Hz) power of R-R interval variability decreased significantly after both conditions, consistent with similar degrees of vagal withdrawal; 3) transfer function gain (BP to R-R interval), used as an index of arterial-cardiac baroreflex sensitivity, decreased significantly to a similar extent after both conditions in the high-frequency range; the gain also decreased similarly when expressed as BP to heart rate x stroke volume, which provides an index of the ability of the baroreflex to alter BP by modifying systemic flow; and 4) however, the low-frequency (0.05-0.15 Hz) power of systolic BP variability decreased after bed rest (-22%) compared with an increase (+155%) after acute hypovolemia, suggesting a differential response for the regulation of vascular resistance (interaction, P < 0.05). The similarity of changes in the reflex control of the circulation under both conditions is consistent with the hypothesis that reductions in plasma volume may be largely responsible for the observed changes in cardiac

  12. Intermittent electrical stimulation of the right cervical vagus nerve in salt-sensitive hypertensive rats: effects on blood pressure, arrhythmias, and ventricular electrophysiology

    PubMed Central

    Annoni, Elizabeth M; Xie, Xueyi; Lee, Steven W; Libbus, Imad; KenKnight, Bruce H; Osborn, John W; Tolkacheva, Elena G

    2015-01-01

    Hypertension (HTN) is the single greatest risk factor for potentially fatal cardiovascular diseases. One cause of HTN is inappropriately increased sympathetic nervous system activity, suggesting that restoring the autonomic nervous balance may be an effective means of HTN treatment. Here, we studied the potential of vagus nerve stimulation (VNS) to treat chronic HTN and cardiac arrhythmias through stimulation of the right cervical vagus nerve in hypertensive rats. Dahl salt-sensitive rats (n = 12) were given a high salt diet to induce HTN. After 6 weeks, rats were randomized into two groups: HTN-Sham and HTN-VNS, in which VNS was provided to HTN-VNS group for 4 weeks. In vivo blood pressure and electrocardiogram activities were monitored continuously by an implantable telemetry system. After 10 weeks, rats were euthanized and their hearts were extracted for ex vivo electrophysiological studies using high-resolution optical mapping. Six weeks of high salt diet significantly increased both mean arterial pressure (MAP) and pulse pressure, demonstrating successful induction of HTN in all rats. After 4 weeks of VNS treatment, the increase in MAP and the number of arrhythmia episodes in HTN-VNS rats was significantly attenuated when compared to those observed in HTN-Sham rats. VNS treatment also induced changes in electrophysiological properties of the heart, such as reduction in action potential duration (APD) during rapid drive pacing, slope of APD restitution, spatial dispersion of APD, and increase in conduction velocity of impulse propagation. Overall, these results provide further evidence for the therapeutic efficacy of VNS in HTN and HTN-related heart diseases. PMID:26265746

  13. Angiotensin Type 2 Receptors in the Intermediolateral Cell Column of the Spinal Cord: Negative Regulation of Sympathetic Nerve Activity and Blood Pressure

    PubMed Central

    Chao, Jie; Gao, Juan; Parbhu, Karma-Jaya K.; Gao, Lie

    2013-01-01

    BACKGROUND Our previous study demonstrated that AT2R in brainstem nuclei participated in the regulation of sympathetic outflow and cardiovascular function. However, the functional significance of AT2R in the intermediolateral cell column (IML) of the thoracic spinal cord in normal rats remains elusive. We hypothesized that AT2R activation in the IML exert a sympatho-inhibitory effect. METHODS and RESULTS Using Western-blot analysis, immunohistochemical staining and quantitative Real-Time PCR, both AT1R and AT2R expression were detected in the spinal cord. The highest AT2R protein expression was found in the IML, while AT1R expression didn’t display regional differences within the gray matter. Microinjection of AngII into the IML dose-dependently elevated mean blood pressure (MAP, employing a transducer-tipped catheter) and renal sympathetic nerve activity (RSNA, using a pair of platinum-iridium recording electrodes), which was completely abolished by Losartan, and attenuated by TEMPOL and apocynin. Activation of AT2R in the IML with CGP42112 evoked hypotension (ΔMAP: −21 ± 4 mmHg) and sympatho-inhibition (RSNA: 73 ± 3% of baseline), which were completely abolished by PD123319 and L-NAME. Blockade of AT2R in the IML with PD123319 significantly increased MAP (11 ± 1 mmHg) and sympathetic nerve activity (RSNA: 133 ± 13 % of baseline). Moreover, PD123319 significantly enhanced the AngII induced pressor response. Furthermore, in isolated IML neurons, CGP42112 treatment augmented potassium current and decreased resting membrane potential by employing whole-cell patch clamp. Conclusion In the normal condition, AT2R in the IML tonically inhibit sympathetic activity through an NO/NOS dependent pathway and subsequent potassium channel activation. PMID:23871345

  14. Murder or Not? Cold Temperature Makes Criminals Appear to Be Cold-Blooded and Warm Temperature to Be Hot-Headed

    PubMed Central

    Gockel, Christine; Kolb, Peter M.; Werth, Lioba

    2014-01-01

    Temperature-related words such as cold-blooded and hot-headed can be used to describe criminal behavior. Words associated with coldness describe premeditated behavior and words associated with heat describe impulsive behavior. Building on recent research about the close interplay between physical and interpersonal coldness and warmth, we examined in a lab experiment how ambient temperature within a comfort zone influences judgments of criminals. Participants in rooms with low temperature regarded criminals to be more cold-blooded than participants in rooms with high temperature. Specifically, they were more likely to attribute premeditated crimes, ascribed crimes resulting in higher degrees of penalty, and attributed more murders to criminals. Likewise, participants in rooms with high temperature regarded criminals to be more hot-headed than participants in rooms with low temperature: They were more likely to attribute impulsive crimes. Results imply that cognitive representations of temperature are closely related to representations of criminal behavior and attributions of intent. PMID:24788725

  15. Murder or not? Cold temperature makes criminals appear to be cold-blooded and warm temperature to be hot-headed.

    PubMed

    Gockel, Christine; Kolb, Peter M; Werth, Lioba

    2014-01-01

    Temperature-related words such as cold-blooded and hot-headed can be used to describe criminal behavior. Words associated with coldness describe premeditated behavior and words associated with heat describe impulsive behavior. Building on recent research about the close interplay between physical and interpersonal coldness and warmth, we examined in a lab experiment how ambient temperature within a comfort zone influences judgments of criminals. Participants in rooms with low temperature regarded criminals to be more cold-blooded than participants in rooms with high temperature. Specifically, they were more likely to attribute premeditated crimes, ascribed crimes resulting in higher degrees of penalty, and attributed more murders to criminals. Likewise, participants in rooms with high temperature regarded criminals to be more hot-headed than participants in rooms with low temperature: They were more likely to attribute impulsive crimes. Results imply that cognitive representations of temperature are closely related to representations of criminal behavior and attributions of intent. PMID:24788725

  16. Role of the vegus nerve in epilepsy (image)

    MedlinePlus

    The vagus nerves branch off the brain on either side of the head and travel down the neck, along the esophagus to the intestinal tract. They are the longest nerves in the body, and affect swallowing and speech. ...

  17. Determining degree of optic nerve edema from color fundus photography

    NASA Astrophysics Data System (ADS)

    Agne, Jason; Wang, Jui-Kai; Kardon, Randy H.; Garvin, Mona K.

    2015-03-01

    Swelling of the optic nerve head (ONH) is subjectively assessed by clinicians using the Frisén scale. It is believed that a direct measurement of the ONH volume would serve as a better representation of the swelling. However, a direct measurement requires optic nerve imaging with spectral domain optical coherence tomography (SD-OCT) and 3D segmentation of the resulting images, which is not always available during clinical evaluation. Furthermore, telemedical imaging of the eye at remote locations is more feasible with non-mydriatic fundus cameras which are less costly than OCT imagers. Therefore, there is a critical need to develop a more quantitative analysis of optic nerve swelling on a continuous scale, similar to SD-OCT. Here, we select features from more commonly available 2D fundus images and use them to predict ONH volume. Twenty-six features were extracted from each of 48 color fundus images. The features include attributes of the blood vessels, optic nerve head, and peripapillary retina areas. These features were used in a regression analysis to predict ONH volume, as computed by a segmentation of the SD-OCT image. The results of the regression analysis yielded a mean square error of 2.43 mm3 and a correlation coefficient between computed and predicted volumes of R = 0:771, which suggests that ONH volume may be predicted from fundus features alone.

  18. Nerve biopsy

    MedlinePlus

    ... Loss of axon tissue Metabolic neuropathies Necrotizing vasculitis Sarcoidosis Risks Allergic reaction to the local anesthetic Discomfort ... Neurosarcoidosis Peripheral neuropathy Primary amyloidosis Radial nerve dysfunction Sarcoidosis Tibial nerve dysfunction Update Date 6/1/2015 ...

  19. Nerve conduction

    MedlinePlus Videos and Cool Tools

    ... the spinal cord to muscles and sensory receptors. A peripheral nerve is composed of nerve bundles (fascicles) ... two neurons, it must first be converted to a chemical signal, which then crosses a space of ...

  20. Effect of acute high-intensity resistance exercise on optic nerve sheath diameter and ophthalmic artery blood flow pulsatility.

    PubMed

    Lefferts, W K; Hughes, W E; Heffernan, K S

    2015-12-01

    Exertional hypertension associated with acute high-intensity resistance exercise (RE) increases both intravascular and intracranial pressure (ICP), maintaining cerebrovascular transmural pressure. Carotid intravascular pressure pulsatility remains elevated after RE. Whether ICP also remains elevated after acute RE in an attempt to maintain the vessel wall transmural pressure is unknown. Optic nerve sheath diameter (ONSD), a valid proxy of ICP, was measured in 20 participants (6 female; 24 ± 4 yr, 24.2 ± 3.9 kg m(-)(2)) at rest (baseline), following a time-control condition, and following RE (5 sets, 5 repetition maximum bench press, 5 sets 10 repetition maximum biceps curls) using ultrasound. Additionally, intracranial hemodynamic pulsatility index (PI) was assessed in the ophthalmic artery (OA) by using Doppler. Aortic pulse wave velocity (PWV) was obtained from synthesized aortic pressure waveforms obtained via a brachial oscillometric cuff and carotid pulse pressure was measured by using applanation tonometry. Aortic PWV (5.2 ± 0.5-6.0 ± 0.7 m s(-1), P < 0.05) and carotid pulse pressure (45 ± 17-59 ± 19 mm Hg, P < 0.05) were significantly elevated post RE compared with baseline. There were no significant changes in ONSD (5.09 ± 0.7-5.09 ± 0.7 mm, P > 0.05) or OA flow PI (1.35 ± 0.2-1.38 ± 0.3, P > 0.05) following acute RE. In conclusion, during recovery from acute high-intensity RE, there are increases in aortic stiffness and extracranial pressure pulsatility in the absence of changes in ICP and flow pulsatility. These findings may have implications for alterations in cerebral transmural pressure and cerebral aneurysmal wall stress following RE. PMID:25739332

  1. Does the preoperative administration of tranexamic acid reduce perioperative blood loss and transfusion requirements after head neck cancer surgery? A randomized, controlled trial

    PubMed Central

    Das, Anjan; Chattopadhyay, Surajit; Mandal, Debabrata; Chhaule, Subinay; Mitra, Tapobrata; Mukherjee, Anindya; Mandal, Subrata Kumar; Chattopadhyay, Sandip

    2015-01-01

    Background: Head and neck cancer (HNC) surgery is associated with high intraoperative blood loss which may require urgent blood transfusion. Many strategies have been recommended to decrease the need for allogenic transfusion. Use of perioperative tranexamic acid (TA) has a promising role. Aims: This study was to evaluate the effectiveness of single preoperative bolus dose of TA on blood loss prevention and red blood cell transfusion in patients undergoing HNC surgery. Study Design: A prospective, double-blind, and randomized controlled study. Materials and Methods: From 2007 July to 2010 January; 80 patients, aged (35–55), of American Society of Anesthesiologists II-III scheduled for unilateral HNC surgeries were randomly received either TA (Group T) in a dose of 20 mg/kg diluted to 25 cc with normal saline or an equivalent volume of normal saline (Group C) in a tertiary care hospital. Hemoglobin (Hb) concentration, platelet count, packed cell volume, fibrinogen level, D-dimer level were measured pre- and post-operatively. Results: Saline (C) Group required more blood, colloid, crystalloid for blood loss. In Group T, 32 patients did not require transfusion of any blood products compared to five patients in Group C (P < 0.0001) and only eight units of blood was transfused in Group T, whereas a total of 42 units of blood was transfused in Group C. Even after numerous transfusions, Hb% after 6 h and 24 h in Group C were significantly low in comparison with Group T (P < 0.05). Conclusion: Thus, TA significantly reduces blood loss and chances of colloid, blood, and crystalloid transfusion caused by HNC surgery. PMID:26712979

  2. Nerve injury associated with orthognathic surgery. Part 1: UK practice and motor nerve injuries.

    PubMed

    Bowe, D C; Gruber, E A; McLeod, N M H

    2016-05-01

    The head and neck is anatomically complex, and several nerves are at risk during orthognathic operations. Some injuries to nerves are reported more commonly than others. To find out what consultant surgeons tell their patients about the prevalence of common nerve injuries before orthognathic operations, we did a postal survey of fellows of the British Association of Oral and Maxillofacial Surgeons (BAOMS). We also reviewed published papers to find out the reported incidence of injuries to cranial motor nerves during orthognathic operations. Only injuries to the facial nerve were commonly reported, and we found only case reports about injuries to the oculomotor, abducens, and trochlear nerves. The risk of temporary facial nerve palsy reported was 0.30/100 nerves (95% CI 0.23 to 0.50) and permanent facial nerve palsy was 0.06/100 nerves (95% CI 0.02 to 0.15). PMID:26935213

  3. Post-graze recovery of blood circulation in steers exhibiting fescue toxicosis as influenced by seed head suppression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seed heads of tall fescue can be chemically suppressed and eliminated as a source of toxic ergot alkaloids, but a reduction in alkaloid-induced vasoconstriction has not been determined in seed head suppressed tall fescue. A preliminary pen experiment was conducted with 30 steers to compare vasoconst...

  4. Comparison of Perioperative Blood Loss in Primary Non-cemented Total Hip Arthroplasty for Rapidly Destructive Coxarthrosis and Osteonecrosis of the Femoral Head

    PubMed Central

    Song, Joo-Hyoun; Han, Suk Ku; Lee, Kyung-Hoon; Lee, Jae-Min

    2015-01-01

    Purpose The purpose of this study is to compare the perioperative blood loss in primary non-cemented total hip arthroplasty (THA) performed for rapidly destructive coxarthrosis (RDC) with the perioperative blood loss in primary non-cemented THA for typical osteonecrosis of the femoral head (ONFH). Materials and Methods From January 2000 to December 2013, 19 patients were diagnosed with RDC (group 1) and 40 patients were diagnosed typical Ficat stage IV ONFH (group 2), comparison of perioperative blood loss between group 1 and group 2 in primary noncemented THA was done. Patients with preoperative usage of steroid or anticoagulants medication and with hemodynamic abnormal blood test results were excluded. The blood loss was measured up to the fifth post operation day and calculated with formula proposed by Mercuriali, Inghilleri and Nadler. Results Non-compensated blood loss calculated in milliliters of red blood cells was 362 mL (standard deviation [SD], 187; range, 77-675) in group 1 and 180 mL (SD, 145; range, 53-519) in group 2. Compensated blood loss was 630 mL (SD, 180; range, 380-760) in group 1 and 503 mL (SD, 260; range, 190-1, 505) in group 2. The total blood loss after primary non-cemented THA is greater when surgery is performed for RDC than for ONFH, with the volume of 992 mL (SD, 300; range, 457-1, 434) in group 1 and 683 mL (SD, 360; range, 226-1, 975) in group 2 respectively. Conclusion Total perioperative blood loss was significantly greater in RDC than in ONFH in primary non-cemented THA. PMID:27536617

  5. Blood volume regulating hormones response during two space related simulation protocols: Four-week confinement and head-down bed-rest

    NASA Astrophysics Data System (ADS)

    Maillet, A.; Gauquelin, G.; Gunga, H. C.; Fortrat, J. O.; Kirsch, K.; Guell, A.; Bizollon, Ch. A.; Gharib, C.

    1995-04-01

    The volume of regulating hormones (renin, aldosterone, arginine vasopressin and atrial natriuretic factor), electrolytes and creatinine concentrations, and blood pressure were measured in two different four-week experimental protocols: respectively -6 ° head-down bed-rest (5 subjects) and confinement (6 subjects). We observed a significant increase ( P < 0.01 at D2 vs D-5) of systolic blood pressure during confinement and a different level of response for some hormones, especially for arginine vasopressin (300% increase during confinement instead of 50% during bed-rest). The renin-angiotensin-aldosterone system was enhanced during confinement and head-down bed-rest. In both conditions, we obtained a similar pattern of response for blood volume regulating hormones. During confinement, two main factors were inactivity and stress activation of the sympathetic nervous system. In the bed-rest study the response is principally due to the fluid shift and blood volume adaptation but it is not possible to exclude the role of inactivity and stress.

  6. Nerve conduction and electromyography studies.

    PubMed

    Kane, N M; Oware, A

    2012-07-01

    Nerve conduction studies (NCS) and electromyography (EMG), often shortened to 'EMGs', are a useful adjunct to clinical examination of the peripheral nervous system and striated skeletal muscle. NCS provide an efficient and rapid method of quantifying nerve conduction velocity (CV) and the amplitude of both sensory nerve action potentials (SNAPs) and compound motor action potentials (cMAPs). The CV reflects speed of propagation of action potentials, by saltatory conduction, along large myelinated axons in a peripheral nerve. The amplitude of SNAPs is in part determined by the number of axons in a sensory nerve, whilst amplitude of cMAPs reflects integrated function of the motor axons, neuromuscular junction and striated muscle. Repetitive nerve stimulation (RNS) can identify defects of neuromuscular junction (NMJ) transmission, pre- or post-synaptic. Needle EMG examination can detect myopathic changes in muscle and signs of denervation. Combinations of these procedures can establish if motor and/or sensory nerve cell bodies or peripheral nerves are damaged (e.g. motor neuronopathy, sensory ganglionopathy or neuropathy), and also indicate if the primary target is the axon or the myelin sheath (i.e. axonal or demyelinating neuropathies). The distribution of nerve damage can be determined as either generalised, multifocal (mononeuropathy multiplex) or focal. The latter often due to compression at the common entrapment sites (such as the carpal tunnel, Guyon's canal, cubital tunnel, radial groove, fibular head and tarsal tunnel, to name but a few of the reported hundred or so 'entrapment neuropathies'). PMID:22614870

  7. Retinal Blood Vessel Distribution Correlates With the Peripapillary Retinal Nerve Fiber Layer Thickness Profile as Measured With GDx VCC and ECC

    PubMed Central

    Resch, Hemma; Pereira, Ivania; Weber, Stephanie; Holzer, Stephan; Fischer, Georg

    2015-01-01

    Purpose: Aim of the present study was to evaluate whether there is a correlation between retinal blood vessel density (RVD) and the peripapillary retinal nerve fiber layer (RNFL) thickness profile. Methods: RNFL thickness of 106 healthy subjects was measured using scanning laser polarimetry, GDx variable corneal compensation (VCC), and GDx enhanced corneal compensation (ECC). A proprietary software was developed in MATLAB to measure the peripapillary retinal vessels using scanning laser ophthalmoscopy fundus images, centered on the optic disc measured by Cirrus spectral domain optical coherence tomography. The individual retinal vessel positions and thickness values were integrated in a 64-sector RVD profile and intrasubject and intersubject correlations were calculated. Results: The mean R value±SD for intrasubject correlation between RVD and RNFL thickness measured with GDx VCC and GDx ECC was 0.714±0.157 and 0.629±0.140, with 105 of 106 subjects presenting significant correlations. In the intersubject linear regression analysis for GDx VCC, 33 of 64 (52%) sectors presented a significant Pearson correlation coefficient between RNFL thickness and RVD values, with a mean R value of 0.187±0.135 (P<0.05). Conclusions: Peripapillary RNFL thickness profiles correlate with the RVD over 50% of the sectors and might explain up to 26% of the interindividual variance of the peripapillary RNFL thickness values as measured with GDx VCC. To our opinion, taking into account RVD might reduce interindividual variation in peripapillary RNFL thickness profiles measured with scanning laser polarimetry. PMID:25719231

  8. Highly Sensitive and Selective Immuno-capture/Electrochemical Assay of Acetylcholinesterase Activity in Red Blood Cells: A Biomarker of Exposure to Organophosphorus Pesticides and Nerve Agents

    SciTech Connect

    Chen, Aiqiong; Du, Dan; Lin, Yuehe

    2012-02-09

    Acetylcholinesterase (AChE) enzyme activity in red blood cells (RBCs) is a useful biomarker for biomonitoring of exposures to organophosphorus (OP) pesticides and chemical nerve agents. In this paper, we reported a new method for AChE activity assay based on selective immuno-capture of AChE from biological samples followed by enzyme activity assay of captured AChE using a disposable electrochemical sensor. The electrochemical sensor is based on multiwalled carbon nanotubes-gold nanocomposites (MWCNTs-Au) modified screen printed carbon electrode (SPCE). Upon the completion of immunoreaction, the target AChE (including active and inhibited) is captured onto the electrode surface and followed by an electrochemical detection of enzymatic activity in the presence of acetylthiocholine. A linear response is obtained over standard AChE concentration range from 0.1 to 10 nM. To demonstrate the capability of this new biomonitoring method, AChE solutions dosed with different concentration of paraoxon were used to validate the new AChE assay method. AChE inhibition in OP dosed solutions was proportional to its concentration from 0.2 to 50 nM. The new AChE activity assay method for biomonitoring of OP exposure was further validated with in-vitro paraoxon-dosed RBC samples. The established electrochemical sensing platform for AChE activity assay not only avoids the problem of overlapping substrate specificity with esterases by using selective antibody, but also eliminates potential interference from other electroactive species in biological samples. It offers a new approach for sensitive, selective, and rapid AChE activity assay for biomonitoring of exposures to OPs.

  9. Pre-Operative Image-based Segmentation of the Cranial Nerves and Blood Vessels in Microvascular Decompression: Can we Prevent Unnecessary Explorations?

    PubMed Central

    Dolati, P; Golby, A; Eichberg, D; Abolfotoh, M; Dunn, IF; Mukundan, S; Hulou, MM; Al-Mefty, O

    2016-01-01

    Objectives This study was conducted to validate the accuracy of image-based pre-operative segmentation using the gold standard endoscopic and microscopic findings for localization and pre-operative diagnosis of the offensive vessel. Patients and Methods Fourteen TN and 6 HS cases were randomly selected. All patients had 3T MRI, which included thin-sectioned 3D space T2, 3D Time of Flight and MPRAGE Sequences. Imaging sequences were loaded in BrainLab iPlanNet and fused. Individual segmentation of the affected cranial nerves and the compressing vascular structure was performed by a neurosurgeon, and the results were compared with the microscopic and endoscopic findings by two blinded neurosurgeons. For each case, at least three neurovascular landmarks were targeted. Each segmented neurovascular element was validated by manual placement of the navigation probe over each target, and errors of localization were measured in mm. Results All patients underwent retro-sigmoid craniotomy and MVD using both microscope and endoscope. Based on image segmentation, the compressing vessel was identified in all cases except one, which was also negative intraoperatively. Perfect correspondence was found between image-based segmentation and endoscopic and microscopic images and videos (Dice coefficient of 1). Measurement accuracy was 0.45+/-0.21 mm (mean +/-SD). Conclusion Image-based segmentation is a promising method for pre-operative identification and localization of offending blood vessels causing HFS and TN. Using this method may prevent some unnecessary explorations on especially atypical cases with no vascular contacts. However, negative pre-operative image segmentation may not preclude one from exploration in classic cases of TN or HFS. A multicenter study with larger number of cases is recommended. PMID:26476700

  10. Effect of Artificial Nerve Conduit Vascularization on Peripheral Nerve in a Necrotic Bed

    PubMed Central

    Iijima, Yuki; Murayama, Akira; Takeshita, Katsushi

    2016-01-01

    Background: Several types of artificial nerve conduit have been used for bridging peripheral nerve gaps as an alternative to autologous nerves. However, their efficacy in repairing nerve injuries accompanied by surrounding tissue damage remains unclear. We fabricated a novel nerve conduit vascularized by superficial inferior epigastric (SIE) vessels and evaluated whether it could promote axonal regeneration in a necrotic bed. Methods: A 15-mm nerve conduit was implanted beneath the SIE vessels in the groin of a rat to supply it with blood vessels 2 weeks before nerve reconstruction. We removed a 13-mm segment of the sciatic nerve and then pressed a heated iron against the dorsal thigh muscle to produce a burn. The defects were immediately repaired with an autograft (n = 10), nerve conduit graft (n = 8), or vascularized nerve conduit graft (n = 8). Recovery of motor function was examined for 18 weeks after surgery. The regenerated nerves were electrophysiologically and histologically evaluated. Results: The vascularity of the nerve conduit implanted beneath the SIE vessels was confirmed histologically 2 weeks after implantation. Between 14 and 18 weeks after surgery, motor function of the vascularized conduit group was significantly better than that of the nonvascularized conduit group. Electrophysiological and histological evaluations revealed that although the improvement did not reach the level of reinnervation achieved by an autograft, the vascularized nerve conduit improved axonal regeneration more than did the conduit alone. Conclusion: Vascularization of artificial nerve conduits accelerated peripheral nerve regeneration, but further research is required to improve the quality of nerve regeneration. PMID:27257595