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Biomedical subjects

V Golovchinsky

Publications and source records attributed to V Golovchinsky.

8 recordsLinked to original sources
PubMed1998

Double crush syndrome in lower extremities.

Retrospective analysis of results of electromyography and nerve conduction velocity was performed in 169 patients with lower back pain, mostly caused by trauma. A total 289 peroneal, 280 posterior tibial and 301 sural nerves were included in statistical analysis. Peripheral entrapment of nerves (tarsal tunnel syndrome and anterior tarsal tunnel syndrome) were found in 5.3% of patients, signs of acute or chronic partial muscle denervation of corresponding muscles of lower extremities in 21.8% of patients, and abnormally prolonged F-wave latency in 12.5% of patients. Combined partial denervation and abnormally prolonged F-wave latency were found in 6.2% of patients, combined partial denervation and peripheral entrapment of nerves in 4.4% of patients, combined abnormally prolonged F-wave latency and peripheral entrapment of nerves in 2.4% of patients and combined partial denervation, abnormally prolonged F-wave latency and peripheral entrapment of nerves in 3.5% of patients. Statistical analysis of these data showed significantly higher than random overlap of peripheral entrapment syndromes and signs of proximal nerve damage of the corresponding nerves (partial muscle denervation or abnormalities of F-wave). This higher than random coincidence of the two conditions strongly suggests cause-and-effect relationship of damage of the proximal stretch of motor nerve fibers and development of peripheral entrapment syndromes in the same nerves rather than a random coincidence of two independent pathologies. Appreciation of this causal relationship is important in the development of comprehensive approach to treatment of peripheral entrapment syndromes. In appropriate cases, simultaneous treatment of the lower back problem should be considered as well.

Adolescent↗
PubMed1990

Ulnar-to-median anastomosis and its role in the diagnosis of lesions of the median nerve at the elbow and the wrist.

Several anatomical and electrophysiological studies demonstrated the possibility of an ulnar-to-median anastomosis in the hand and the forearm--a "reversed Martin-Gruber anastomosis". Observations supporting this possibility were obtained in the course of routine clinical testing of nerve conduction velocity in upper extremities. The existence of an ulnar-to-median anastomosis was suggested when, in absence of clinical signs of the pronator syndrome or the anterior interosseus nerve syndrome, the amplitude of compound muscle action potential in the opponens pollicis was larger at stimulation of the median nerve at the wrist than at the elbow. When an ulnar-to-median anastomosis is suspected, special care should be exerted in evaluation of motor distal latency of the median nerve with a gradual and slow increase of the stimulus voltage. Use of high voltage from the beginning can simultaneously activate both the median nerve and a collateral branch of the ulnar nerve, the later bypassing the carpal tunnel and evoking a short latency response in the thenar muscles, with the simultaneous long latency response to the stimulation of the median nerve being masked by this fast response. Based on the same anatomical considerations, a decreased amplitude of the compound muscle action potential of the opponens pollicis at proximal stimulation, as compared with that at distal stimulation, should not be interpreted as an indication of a damage of the median nerve at the forearm.

Action Potentials↗
PubMed1981

Properties of velocity-mechanosensitive neurons of the cat ventrobasal thalamic nucleus with special reference to the concept of convergence.

Neurons in the ventrobasal (VB) thalamic nucleus of lightly anesthetized cats were studied in order to analyze their discharge properties in response to controlled mechanical stimuli. Properties of the vast majority of the neuronal population largely resemble those of peripheral sensitive mechanoreceptors in their response to the velocity and, to a more limited extent, the amplitude component, of skin and hair displacement within restricted receptive fields. Detailed examination reveals some 'complex' characteristics suggestive of central integration in about 11% of VB neurons. Complex properties appear to indicate convergent input reflecting receptive field organization, the variety of velocity-related discharges and patterns of inhibition. The rarity of isolated 'surround' inhibition and the definition of what constitutes 'lemniscal' properties are discussed in the context of these and other related findings.

Afferent Pathways↗
PubMed1981

Ketamine: convulsant or anti-convulsant?

Ketamine hydrochloride in doses producing narcotic-cataleptic effects (50--100 mg/kg, IP) reduced the intensity of picrotoxin convulsions and eliminated seizures caused by metrazol administration. Subcataleptic doses (5--20 mg/kg) increased the duration of mitigated convulsive symptoms (abortive grand mal fits, jerks) especially those evoked by picrotoxin. Narcotic-cateleptic doses of ketamine considerably increased the duration of the period of single and multiple jerks produced by picrotoxin administration. Both convulsants transformed 1--2 Hz "ketamine complexes" into 2--4 Hz Wave spike discharges which appeared in a quasi-periodic fashion alternating with periods of relatively suppressed electrocortical activity. Electroencephalographic grand mal patterns were typically dissociated from behavioral manifestations under 50--100 mg/kg of ketamine, followed by a short period of postictal depression and a rapid recovery of preseizure electrographic patterns. Findings suggest that mechanisms involved in seizure alleviation may be responsible for sustaining mitigated convulsive phenomena. Neuro-chemical processes underlying antiepileptic ketamine potency remain unknown.

Animals↗
PubMed1980

Patterns of responses of neurons in cuneate nucleus to controlled mechanical stimulation of cutaneous velocity receptors in the cat.

1. The responses of single cuneate neurons to controled mechanical stimulation of skin were recorded in cats lightly anesthetized with a nitrous oxide-halothane mixture. The discharge patterns and peripheral receptive-field characteristics were studied in neurons driven by sensitive cutaneous mechanoreceptors, including slowly adapting skin mechanoreceptors. Virtually all cuneate neurons display maximum discharge during the velocity component of displacement. 2. Among cuneate neurons encountered in this study, approximately 46% were driven by guard hair mechanoreceptors, 15% were driven by field receptors, and 13% were driven by slowly adapting skin receptors. Neurons responding to stimulation of deep tissues (including claws) were not studied with controlled mechanical stimulation and accounted for 19%. The rest of the neurons were driven by Pacinian corpuscles, received afferent inputs from several different first-order afferents, or were not definitely identified. There was no clear evidence of down hair or high-threshold mechanoreceptor representation. 3. The discharge pattern in response to a constant-velocity stimulus proved most valuable in describing submodality classes of neurons driven by hair and field receptors since sensitivity of these neurons to dynamic and to static phases of stimulation constitute respective continua and, thus, preclude sharp separation into distinct groups. 4. The majority of neurons displayed response properties and receptive fields similar to those of first-order afferents. A minority of cells had receptive fields that were larger than those of primary afferents, with nearly identical modality and velocity characteristics throughout the receptive field. 5. Approximately 2% of recorded neurons displayed convergent properties not encountered in first-order afferents, including neurons driven from receptors of different modalities or from discontinuous receptive fields. 6. Inhibition of neuronal firing generated from outside the receptive field was rarely seen, possibly due to anesthetic conditions. In a small number of neurons, irregularities in the discharge were observed that might indicate inhibitory influences originating from within the receptive field.

Afferent Pathways↗
PubMed1979

Ketamine-induced rotation: interaction with GABA-transaminase inhibitors and picrotoxin.

Ketamine in a dose of 100 mg/kg (IP) produced stereotypic behavior and vigorous rotation in adult male Sprague-Dawley rats. The first rotation phase, accompanied by head swinging, was short and terminated by the anesthetic phase which lasted 20-30 min. The second rotation phase began 1-3 min after the end of the anesthetic phase. A single dose of GABA-T inhibitors, gamma-vinyl GABA (1200 mg/kg, IP) or gamma-acetylenic GABA (100 mg/kg, IP) administered 4 hours prior to ketamine, shortened the first rotation phase, increased the anesthetic phase, changed the pattern of postanesthetic rotation and reduced total and net rotation scores. Picrotoxin (3 mg/kg) given 10 min prior to ketamine tended to act in the opposite direction although none of its effects reached statistical significance.

4-Aminobutyrate Transaminase↗