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Biomedical subjects

B Shahani

Publications and source records attributed to B Shahani.

13 recordsLinked to original sources
PubMed1992

An antispasticity effect of threonine in multiple sclerosis.

To determine whether the naturally occurring amino acid threonine, a potential precursor for glycine biosynthesis in the spinal cord, has an effect on spasticity in multiple sclerosis, 26 ambulatory patients were entered into a randomized crossover trial. Threonine administered at a total daily dose of 7.5 g reduced signs of spasticity on clinical examination, although no symptomatic improvement could be detected by the examining physician or the patient. In contrast to the side effects of sedation and increased motor weakness associated with antispasticity drugs commonly used for the treatment of multiple sclerosis, no side effects or toxic effects of threonine were identified. Levels of threonine were elevated in serum and cerebrospinal fluid during treatment, but glycine levels did not change. Enhancement by threonine of glycinergic postsynaptic inhibition of the motor reflex arc in the spinal cord may represent a non-sedating, nontoxic approach to the management of spasticity in multiple sclerosis.

Adult↗
PubMed1992

Comparison of electric and magnetic coil stimulation in the supraclavicular region.

We compared the compound motor action potentials (CMAPs) evoked in the biceps, triceps, and abductor digiti minimi (ADM) muscles by conventional electrical stimulation at Erb's point (EP), and by magnetic coil stimulation of the supraclavicular region in 11 normal subjects. We found that magnetic coil stimulation was less effective than conventional stimulation in activating motor fibers in the brachial plexus in 45% of the recordings analyzed. CMAP amplitudes greater than those obtained with EP electrical stimulation were seen in 16% of recordings with supraclavicular magnetic stimulation, and in 33% of recordings with cervical magnetic stimulation, indicating that EP electrical stimulation is submaximal in a large proportion of cases.

Action Potentials↗
PubMed1990

Magnetic stimulation F-responses.

We used the 9 cm Cadwell magnetic coil, stimulating at the wrist, to obtain simultaneous median and ulnar nerve F-responses. Surface recording was performed from conventional thenar and hypothenar sites. It is known that with this type of coil it is difficult to accomplish selective supramaximal stimulation of the median or ulnar nerve individually. We found it possible, however, to record a compound muscle action potential of supramaximal or near supramaximal amplitude, as well as F-responses, in both thenar and hypothenar muscles simultaneously. We assessed this technique for F-response latency determination in controls and patients with carpal tunnel syndrome. In controls, there was no significant difference in the F-minimal latency or the F-minimum-maximum range obtained by the two methods. In patients with carpal tunnel syndrome, with median F-responses very delayed or absent on conventional testing, magnetically elicited thenar F-responses were of shorter latency, similar to F's recorded in the hypothenar muscles, suggesting they were recorded from ulnar innervated thenar muscles. Although magnetic stimulation allows simultaneous determination of median and ulnar F-latencies, sparing patients several painful stimuli, and shortening the electrophysiologic examination, magnetic stimulation in patients with carpal tunnel syndrome may elicit thenar recorded F-responses that are not of median origin. Use of this technique is limited by the lack of focality of the stimulus, which has been the major limiting factor in its use on peripheral nerves.

Action Potentials↗
PubMed1971

Motor neurone disease. Further evidence for an abnormality of nerve metabolism.

Physiological and biochemical studies were carried out on 16 patients with motor neurone disease (MND). It was confirmed that the peripheral nerves in cases of MND are often unusually resistant to ischaemia especially as regards the large sensory fibres. Biochemical investigations demonstrated a tendency to carbohydrate intolerance and abnormal pyruvate metabolism. When compared with other related studies in MND it seems very likely that there is a metabolic abnormality present in MND which demands further study.

Action Potentials↗
PubMed1970

Flexor reflex afferent nerve fibres in man.

Flexor reflex afferent nerve fibres have been identified in the mixed peripheral nerve and measurement of their conduction velocity has been carried out. It has been demonstrated that the flexor reflex afferent fibres have a higher threshold of stimulation than the motor fibres supplying the foot muscles. The effect of conditioning volleys in the flexor reflex afferent fibres on the H reflex has been determined and reciprocal inhibition of extensor motoneurones has been found to be related to the second component of the flexor reflex.

Adolescent↗
PubMed1970

The human blink reflex.

A detailed study of the human blink reflex in the different parts of the orbicularis oculi muscle has been carried out. The first component of the blink reflex has been demonstrated in patients with Friedreich's ataxia, who have selective loss of large sensory fibres resulting in loss of proprioceptive input. It has been established that both components of the blink reflex are cutaneous reflexes which represent a highly organized and purposeful mechanism in man. Afferent fibres for the blink reflex have been identified in the human supraorbital nerve and their conduction velocity has been estimated for the first time in man. It has been demonstrated that both components of the blink reflex are mediated by the same group of afferent fibres.

Adolescent↗