Search PubMed⌕ Search

Biomedical subjects

C Biro

Publications and source records attributed to C Biro.

7 recordsLinked to original sources
PubMed1997

Geographic variation in the prevalence of Raynaud's phenomenon: a 5 region comparison.

OBJECTIVE: To determine the population based prevalence of Raynaud's phenomenon (RP) in 5 geographic regions: one in South Carolina, USA, and 4 in France; to explore the relationship of RP to the climate; to investigate possible risk factors; and to describe the characteristics of RP+ subjects in the general population. METHODS: The study consisted of 2 phases: a telephone survey of a randomly drawn sample of households, with 10,149 completed interviews; these were followed by a face to face interview and clinical evaluation (n = 1,534), including diagnosis of RP. The same methodology was used in all 5 regions: for recruitment of subjects, criteria for RP, method of RP diagnosis, and for gathering additional information. RESULTS: The prevalence of RP was found to be related to the climate. The relationship between RP and climate was complicated, however, by the fact that many subjects had moved between climate zones. The relationship of RP to a cold climate became more evident after taking the migration patterns into account: the majority of RP+ subjects in the 2 coldest regions had lived all their lives in the same or a similar climate zone; the majority of RP+ subjects in the 2 warmest regions had previously lived in a colder climate. Other factors associated with RP were family history of RP, cardiovascular diseases, older age, a low body mass index, use of vibrating tools, and outings of a day or more. The classical triphasic RP was rarely encountered in the general population and the most frequently observed signs and symptoms during an RP attack were blanching accompanied by numbness. CONCLUSION: In addition to being a triggering factor for RP attacks, cold also appears to be an etiologic factor in the pathogenesis of RP. A subclinical cold injury, more likely to occur in colder climates, may be responsible for the "local fault" that has been implicated in the pathogenesis of RP and, in association with other risk factors, may predispose subjects to develop clinical RP.

Activities of Daily Living↗
PubMed1996

Intraoperative improvements of somatosensory evoked potentials: correlation to clinical outcome in surgery for cervical spondylitic myelopathy.

STUDY DESIGN: Retrospective review of all patients who underwent surgical treatment of cervical spondylitic myelopathy and were monitored by somatosensory evoked potentials. OBJECTIVES: To identify the patients who had recognizable improvements in somatosensory evoked potential signals intraoperatively and to correlate the changes in somatosensory evoked potential signals to the post-operative clinical status of the patients and compare this group of patients with those that had stable intraoperative somatosensory evoked potential recordings. SUMMARY OF BACKGROUND DATA: Somatosensory evoked potentials are commonly used in the operating room to monitor potential injury to the spinal cord or alterations in spinal cord function. It may be possible to use intraoperative somatosensory evoked potentials to detect improvement in spinal cord function during the decompression of neural structures, as evidenced by an increase in amplitude or a decrease in the latency of the wave form. METHODS: Thirty-two patients with moderate to severe cervical spondylitic myelopathy requiring multi-level anterior decompression and fusion were monitored intraoperatively with somatosensory evoked potentials. The median and posterior tibial nerves were stimulated at the wrist and ankle, respectively. Somatosensory evoked potential recordings were obtained from cervical and scalp electrodes by the Nicolet Pathfinder electrodiagnostic system, preoperatively, intraoperatively, and postoperatively. RESULTS: Eleven of thirty-two patients demonstrated intraoperative improvement of somatosensory evoked potential signals after decompression. All patients had rapid recovery of motor strength, bladder control, and ambulatory capacity within days of surgery. The remaining twenty-one patients had stable somatosensory evoked potential recordings. Five had rapid resolution of their symptoms, 15 improved over the course of 6 to 8 weeks, and 1 did not improve. The motor recovery of this group at 8 weeks was equal to the group of patients that showed intraoperative improvements of evoked potential signals. CONCLUSIONS: 1) Multilevel anterior cervical decompression and fusion produced a significant improvement in the motor function of patients with cervical spondylitic myelopathy. 2) Patients with intraoperative increase in amplitude or shortening of latency had a more rapid clinical improvement than patients with stable recordings. 3) Long-term reassessment did not show any difference between patients with intraoperative somatosensory evoked potential improvement and those with stable somatosensory evoked potential recordings. Therefore, somatosensory evoked potential improvements cannot be used to determine prognosis at the present time. 4) A greater number of patients should be studied using more objective methods for quantifying gait patterns and motor function.

Aged↗
PubMed1994

Axon regeneration after decompression of the conus medullaris.

STUDY DESIGN: The effect of acute spinal stenosis (simulating fracture) and decompression of stenosis on axon regeneration was evaluated in an animal model. OBJECTIVES: Clinical function and quantitative histomorphometry were used to gain insight into the clinicopathologic effects of acute spinal stenosis and decompression. SUMMARY OF BACKGROUND DATA: Decompression of extrinsic compression after thoracolumbar fractures has been suggested to maximize recovery of neurologic function. Clinical studies seem to support this, but the histologic results of decompression are poorly understood. METHODS: Experimental spinal stenosis was created in 5 female beagle dogs, followed by decompression in three of the beagles at 6 weeks. Clinical function and histologic appearance were analyzed using a monoclonal antibody to neurofilaments. RESULTS: Stenosis consistently produced significant neurologic deficit and axon degeneration within motor roots distal to the stenosis. Decompression resulted in improved neurologic function and a tendency for the axons to return to normal number and volume based on quantitative histomorphometry. CONCLUSION: This study provides an animal model and functional and histologic data that support the use of decompression of acute spinal stenosis of 50% or more canal compromise at the level of the conus medullaris and a neurologic deficit. This may be seen clinically in thoracolumbar fractures.

Animals↗
PubMed1990

Urologic changes after cauda equina compression in dogs.

Relative degrees (25%, 50% or 75%) of constriction of the entire cauda equina at the seventh lumbar level were performed on eighteen pure bred female beagle hounds by surgically implanting a circular polyethylene loop with an imbedded stainless steel wire. The wire was mechanically constricted by external control and the degree of compression was confirmed by pre- and postoperative magnetic resonance imaging or computed tomography scanning. A control group of two dogs had laminectomy only. Neurologic function was evaluated daily. Cystometrics were performed on each dog after constriction had been present for three months. Cortical evoked potentials (CEPs) were obtained on all dogs preoperatively, immediately following constriction and at monthly intervals for three months. Dogs were sacrificed at three months and the cauda equina and spinal cord were examined histopathologically. Cystometric tracings were noted to become a flat line with 75% compression of the cord. Less compression had minimal effect on the cystometric curves. The mean latency, determined by cortical evoked potentials, was noted to increase by 3.2%, 7.8%, and 17.2% immediately after 25%, 50% and 75% constriction, respectively. Histologic changes ranged from occasional enlargement of the axons on the periphery of the cauda equina with 25% constriction to severe loss of all axons and atrophic roots at the level of the constricting band with 75% constriction.

Animals↗
PubMed1990

Urologic function after experimental cauda equina compression. Cystometrograms versus cortical-evoked potentials.

Twenty female beagle dogs underwent an L6-7 laminectomy and six dogs each had 25, 50 or 75% constriction of the cauda equina and 2 control dogs had laminectomy only. Cystometrograms were performed pre- and post-operatively and three months after constriction. Cortical evoked potentials were monitored pre- and post-operatively and monthly for three months. After three months of constriction, the cauda equina of these dogs in each group was examined histologically and vascular circulation was examined by latex and India ink injection (Spalteholz technique). The control dogs had normal CMGs and CEPs. Twenty-five percent constriction caused no CMG changes and mild CEP changes. Fifty percent constriction caused no statistically significant CMG changes, major CEP changes and venous congestion of the nerve roots and dorsal root ganglia. Seventy-five percent constriction produced severe CMG changes with detrusor areflexia, increased bladder capacity and clinical incontinence. CEPs also had marked deterioration. Vascular analysis revealed severe arterial narrowing at the level of constriction and venous congestion of the nerve roots and dorsal root ganglia. Blockage of axoplasmic flow and nerve root atrophy was seen in all dogs with 75% constriction. Cortical evoked potentials were the most sensitive predictor of neural compression. CMGs were not sensitive until severe compression was achieved. Bladder dysfunction, i.e., detrusor areflexia, appears to occur with blockage of axoplasmic flow and early sensory changes occur with neurovenous congestion.

Animals↗
PubMed1990

Experimental lumbar spinal stenosis. Analysis of the cortical evoked potentials, microvasculature, and histopathology.

An animal model of lumbar spinal stenosis was developed in which the pathophysiology of this condition could be examined. Four experimental groups, each containing six dogs, were studied. One group had a laminectomy of the sixth and seventh lumbar vertebrae only; these animals served as controls. In the three other groups, a laminectomy was performed and the cauda equina was constricted by 25, 50, or 75 per cent to produce chronic compression. Cortical evoked potentials were recorded preoperatively, immediately after constriction, and at one, two, and three months postoperatively. Daily neurological examinations were carried out, and the neurological deficits were graded using the Tarlov system. After three months of constriction, the cauda equina of three dogs in each group was examined histologically, and the vascular circulation was examined by latex and India-ink injection with a modification of the Spalteholz technique. The animals in the control group showed no neurological abnormalities, no changes in cortical evoked potentials, normal microvascularity, and no histopathological changes in the nerve roots or the spinal cord. The dogs in which the cauda equina had been constricted 25 per cent had no neurological deficits, mild changes in cortical evoked potentials, slight histological changes, and venous congestion of the root and dorsal root ganglion of the seventh lumbar nerve. The dogs in which the cauda equina had been constricted 50 per cent had mild initial motor weakness, major changes in cortical evoked potentials, edema and loss of myelin in the root of the seventh lumbar nerve, and moderate or severe venous congestion of the root and dorsal root ganglion of the seventh lumbar nerve. The dogs in which the cauda equina had been constricted 75 per cent had significant weakness, paralysis of the tail, and urinary incontinence; two dogs recovered by the third month, but all had neurogenic claudication for three months. All six dogs had dramatic changes in cortical evoked potentials and had complete nerve-root atrophy at the level of the constriction. There was blockage of axoplasmic flow and wallerian degeneration of the motor nerve roots distal to the constriction and of the sensory roots proximal to the constriction, as well as degeneration of the posterior column. Severe arterial narrowing at the level of the constriction and venous congestion of the roots and dorsal root ganglia of the seventh lumbar and first sacral nerves were also present. Cortical evoked potentials revealed neurological abnormalities before the appearance of neurological signs and symptoms.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗