PubMed Health⌕ Search

Biomedical subjects

S H Subramony

Publications and source records attributed to S H Subramony.

63 records · Page 4Linked to original sources
PubMed1986

Exercise and rest in hyperkalemic periodic paralysis.

The effect of muscle immobility, with and without prior vigorous exercise, on amplitude and area of the compound muscle action potential (CMAP) to supramaximal nerve stimulation was studied in a family with hyperkalemic periodic paralysis. Amplitude and area of different CMAPs were measured during basal state, sustained immobility, and after brief maximal voluntary exercise of these muscles. Sustained immobility reduced the amplitude and area of the CMAP, with maximal effect occurring after 30 minutes. Though brief intense exercise seemed to minimally accentuate these effects of subsequent immobility at certain times, serial CMAP monitoring over 60 minutes did not reveal major differences between exercised and nonexercised muscles. Muscle immobility in itself can alter the CMAP in hyperkalemic periodic paralysis. Prior intense muscle exercise may accentuate this to some degree. This appears to be the electrophysiologic correlate of the characteristic symptom of focal weakness induced by rest after exercise.

Adult↗
PubMed1986

"Orthostatic tremor' in familial-essential tremor.

We studied a family with essential tremor of the arms. Some members also had tremor of the trunk and legs on standing, but not on walking, sitting, or reclining. Tremor was evoked, regardless of body or limb position, by strong tonic contraction of the appropriate muscles; it was a type of static postural tremor. Beta-adrenergic blockers had no effect on the tremor of the trunk or legs, but clonazepam was beneficial.

Adult↗
PubMed1983

Distinguishing paramyotonia congenita and myotonia congenita by electromyography.

Compound muscle action potential (CMAP) amplitudes, response to 2 Hz nerve stimulation, response to exercise and electromyographic needle electrode examination findings from the thenar muscles of two patients with paramyotonia congenita were compared with those from two patients with dominantly inherited myotonia congenita in warm (34 degrees C) and cold (20 degrees C) states. Cold induced a significant fall in CMAP amplitude, induced/worsened a significant decremental response to 2 Hz stimulation, and virtually abolished myotonia and voluntary recruitment of motor unit potentials in patients with paramyotonia congenita; none of these occurred in myotonia congenita. Though exercise induced a mild fall in CMAP amplitude in both groups, postexercise fibrillations occurred only in patients with paramyotonia congenita. These findings serve to distinguish these two entities in the clinical electromyography laboratory.

Adult↗
PubMed1982

Diabetic proximal neuropathy. Clinical and electromyographic studies.

Clinical and electromyographic findings in 27 diabetics with proximal lower extremity weakness were analyzed. Two groups could be distinguished: patients in whom electromyographic findings were restricted to the clinically involved parts of the lower extremity (group A) and those in whom an associated distal symmetric, peripheral neuropathy could be proved on clinical and electromyographic grounds (group B). Patients in group B had significantly greater incidence of the following features: gradual onset of symptoms, bilateral proximal lower extremity weakness, insulin dependency, recent weight loss, EMG evidence of bilateral disease and paraspinal fibrillations. These findings concur with recent reports describing heterogeneity in the syndrome of "diabetic proximal neuropathy".

Adult↗
PubMed1981

Radicular derivation of sensory action potentials in lower extremity.

A patient with grade II spondylolisthesis and back pain underwent Harrington rod instrumentation. Postoperatively, he developed pain and numbness of the lateral aspect of the left foot and loss of the left AChilles reflex. Preoperative electrodiagnostic findings of the left lower extremity were normal. Two postoperative studies revealed that, concomitant with evidence of denervation if the left S1-supplied muscles, his sural sensory nerve action potential (SNAP) had been abolished but the superficial peroneal SNAP, recorded from the intermediate branch, was normal and equal to that of the contralateral foot. Though various dermatomal maps show this branch to be in the border zone between S1 and L5 dermatomes, the findings in this patient are evidence that the SNAP of the superficial peroneal nerve, recorded as described, is subserved by fibers in the L5 root. In lesions producing axonal loss in L5 root distribution, the amplitude of the superficial peroneal SNAP will be of value in distinguishing lesions at or distal to the dorsal root ganglion from those proximal to it.

Action Potentials↗
PubMedDate not supplied

Mistaken diagnoses in continuous muscle fiber activity of peripheral nerve origin.

The syndrome of continuous muscle fiber activity of peripheral nerve origin has manifestations that resemble those of many other more common neurologic disorders during childhood and infancy. This similarity often leads to misdiagnosis when an adequate index of suspicion is not entertained and a comprehensive electromyographic examination is not performed. Two affected patients from 1 family are reported to illustrate the type of diagnostic errors that were made before the establishment of the correct diagnosis.

Arthrogryposis↗
PubMedDate not supplied

Calcium homeostasis and spinocerebellar ataxia-1 (SCA-1).

Spinocerebellar ataxia-1 (SCA-1) belongs to a group of polyglutamine neurodegenerative disorders characterized by the expansion of a glutamine tract within the mutant disease-causing protein. In SCA-1, the expression of mutant ataxin-1 induces a progressive functional loss and the subsequent degeneration of a set of neurons including cerebellar Purkinje cells. Studies on SCA-1 transgenic mice have provided further understanding of the molecular and cellular events important for the disease. This review discusses what has been learned about the pathogenesis of SCA-1 through the transgenic mouse models in reference to Ca(2+) dependent pathways. This article also discusses the role of Ca(2+) regulating cytoplasmic and nuclear proteins in the pathogenesis of SCA-1. Finally, we discuss the use of double mutant mouse models to understand the association between Ca(2+) binding proteins and Purkinje cell pathology in SCA-1.

Animals↗
PubMedDate not supplied

Electrophysiological findings in crutch palsy.

Detailed electromyographic studies in two patients suffering from crutch palsy revealed conduction blocks along the nerves to the involved upper limbs localized to the axilla. Rapid reversal of the blocks was documented in one patient. Electromyography is of value in delineating such lesions and helping in the formulation of prognosis.

Adult↗