Search PubMed⌕ Search

Biomedical subjects

S Chokroverty

Publications and source records attributed to S Chokroverty.

At least 73 records · Page 4Linked to original sources
PubMed1987

A physiologic and pharmacologic study in anticholinergic-responsive essential myoclonus.

We report the physiologic and pharmacologic analysis in two women, aged 18 and 17 years, with essential myoclonus. Both responded to benztropine mesylate and had been functioning normally. The physiologic analysis suggested ballistic movement overflow and audiogenic stimulus-sensitive myoclonus. The pharmacologic study showed a direct and mutual antagonism of physostigmine and anticholinergic agent on myoclonus, implying cholinergic hyperactivity in the pathophysiology of myoclonus.

Adolescent↗
PubMed1986

Opioid responsiveness in patients with neuroleptic-induced akathisia.

Five patients with either acute or tardive neuroleptic-induced akathisia (5 weeks to 1 1/2 years duration) were videotaped before, during, and after a 2-week trial of propoxyphene (Darvon), 100 mg q.i.d., or acetaminophen (Tylenol) with 30 mg codeine, two tabs, q.i.d. Three "blinded" observers, experienced in movement disorders, rated the involuntary movements shown on the videotapes and agreed that, on opioids, all patients showed substantial to complete improvement of their stereotyped restless akathitic movements. Matching placebo was not beneficial. One patient who had improved on opioids was challenged with naloxone while on the opioids. There was a brief but severe reactivation of the akathisia. Our results suggest that opioids offer a selective therapy for patients with neuroleptic-induced akathisia and further suggest that the endogenous opiate system may be involved in patients with neuroleptic-induced akathisia.

Acetaminophen↗
PubMed1986

Sleep apnea in narcolepsy.

Polysomnographic and multiple sleep latency studies documented recurrent apneic episodes during NREM sleep stages 1 and 2 and REM sleep in 11 of 16 narcoleptic patients. Episodes were predominantly central, but obstructive and mixed events were also observed. Apneas were accompanied by mild to moderate oxygen desaturation.

Adult↗
PubMed1985

Neurophysiologic study of olivopontocerebellar atrophy with or without glutamate dehydrogenase deficiency.

By neurophysiologic investigations, we evaluated 20 patients with olivopontocerebellar atrophy (OPCA), comprising 8 with glutamate dehydrogenase (GDH) deficiency and 12 with normal GDH activity. We found sensorimotor, predominantly sensory axonal neuropathy distally in the legs, and peripheral auditory nerve dysfunction (prolonged wave I but normal interpeak latencies in brainstem auditory evoked response) in GDH-deficient patients. These findings seem distinctive enough to serve as the electrophysiologic marker for diagnosis and monitoring of treatment and progression of the disease. The pattern-reversal visual and median nerve somatosensory evoked responses did not differ among the patients and controls.

Aged↗
PubMed1984

Autonomic dysfunction and sleep apnea in olivopontocerebellar degeneration.

We studied ten men with olivopontocerebellar degeneration. Our findings of the autonomic deficits as manifested by orthostatic hypotension, impaired Valsalva's response, abnormal findings on cold pressor and mental arithmetic tests, and plasma renin and norepinephrine abnormalities in some patients with olivopontocerebellar degeneration suggested a defective central control of the sympathetic nervous system. Five patients had sleep apnea. Autonomic dysfunction and sleep apnea in olivopontocerebellar degeneration may result from degenerative lesions in the cerebellum and the brain stem.

Adult↗
PubMed1984

Pathology of olivopontocerebellar atrophy with glutamate dehydrogenase deficiency.

We report the neuropathologic findings in the first patient with recognized glutamate dehydrogenase (GDH) deficiency to come to postmortem examination. He had progressive cerebellar ataxia beginning at age 21. He died at age 47 of pulmonary emboli. Postmortem examination revealed pancerebellar, olivary, and mild pontine atrophy, demyelination of the posterior columns, degeneration of anterior horn and dorsal root ganglion cells, and reduction of myelinated fibers in the sural nerve. In addition, there was neuronal storage of lipopigment diffusely throughout the CNS and the autonomic neurons, with cell distention, atrophy, and loss in selected areas.

Atrophy↗
PubMed1983

Posterior rhythmic slow activity in EEG after eye closure.

During a 20 month period, EEGs in 7 patients, ages 6-16 years, showed a distinctive posterior rhythmic slow (PRS) activity brought on by eye closure. Following eye opening for 5-10 sec, eye closure on command was followed by a rhythmic high amplitude (100-250 microV) slow wave discharge of 3-4 c/sec lasting for 1.5-3 sec after a latency of 300-500 msec. Its distribution was limited to the occipital, posterior temporal and parietal regions. It was always bilaterally synchronous, occurred symmetrically or asymmetrically and fatigued easily. Of the 7 initial EEGs, only 2 had other EEG abnormalities. One patient, in a subsequent EEG, developed spontaneous PRS unrelated to eye closure. Clinical histories on the 7 patients showed 5 with various types of seizure disorders, 1 with attention deficit disorder, and 1 with Tourette syndrome. Neurological examination was normal in all patients, while computerized tomography or radioisotope brain scan was normal in 4. We suggest that PRS after eye closure represents a variant of the non-specific spontaneously occurring PRS described by Aird and Gastaut and others. It was found only in children and was not found to be helpful in diagnosing a seizure disorder or structural abnormality. Furthermore, such a discharge should not be interpreted as epileptiform activity.

Adolescent↗
PubMed1983

Glutamate dehydrogenase deficiency in patients with olivopontocerebellar atrophy.

Deficiency of glutamate dehydrogenase appears to be associated with a chronic progressive degenerative disorder manifesting parkinsonian extrapyramidal features, ataxia, supranuclear oculomotor dysfunction, a peripheral neuropathy and, in some cases, amyotrophy. The clinical features resemble those of the Dejerine-Thomas type of olivopontocerebellar atrophy. The data suggest autosomal dominant inheritance with low penetrance. Measurement of leukocyte glutamate dehydrogenase should be routinely performed in the evaluation of newly diagnosed or atypical cases of parkinsonism.

Aged↗
PubMed1982

Proximal vs distal slowing of nerve conduction in chronic renal failure treated by long-term hemodialysis.

An F-wave conduction study was performed to determine proximal vs distal slowing of motor nerve conduction in the lower extremities in nine patients with chronic renal failure who were undergoing-long-term hemodialysis and in 11 normal control subjects. The values of the F-wave ratio and the difference between the longest and shortest F-wave latencies were significantly longer than the control values in five patients, implying predominant affection of the proximal peroneal nerve segments. In the remaining patients, the proximal and distal peroneal nerve segments were equally affected. The distal motor nerve conduction velocities of the posterior tibial nerves were also reduced, while the values for the median and ulnar nerves were generally within the normal range. It is important to study multiple F-wave characteristics, in addition to the conventional nerve conduction, for complete assessment of peripheral nerve function in these patients.

Adult↗
PubMed1982

Electroencephalograms in patients with progressive dialytic encephalopathy.

We compared the electroencephalograms (EEGs) of 17 patients with progressive dialytic encephalopathy with 17 chronic renal failure patients who did not have dialytic encephalopathy and who had been matched for age, type and duration of dialysis. The EEGs were analyzed in a semiquantitative fashion by counting the number of paroxysms of frontal intermittent rhythmic delta activity and frontocentral spike-waves, and by grading the amount of diffuse theta and delta waves during waking EEG on a 4-point scale. The two most important EEG predictors of dialytic encephalopathy in the present study consisted of synchronous and symmetrical frontal intermittent rhythmic delta waves and frontocentral spike-waves, confirming our previous observations.

Adult↗
PubMed1981

Primary sleep apnoea syndrome.

Polygraphic study in 18 men with the sleep apnoea syndrome showed central, upper airway obstructive, and mixed apnoeas. Fifty per cent of the total apnoea time was central, 33% was obstructive, and 17% was mixed. Apnoeic episodes were accompanied by oxygen desaturation, relative bradycardia and hypotonia of orofacial muscles innervated by ponto-medullary neurons. During regular breathing these muscles revealed tonic and phasic inspiratory EMG activities. The data suggest that the primary sleep apnoea syndrome results from a dysfunction of the central control of breathing.

Adult↗
PubMed1980

Distribution and size of myofibers in quadriceps muscle of Syrian hamster.

Formalin-fixed myosin adenosine triphosphatase preparations of Syrian hamster quadriceps muscle showed myofibers distributed as follows: (1) vastus intermedius--light and dark fibers; (2) vastus medialis, rectus femoris, and vastus lateralis--light, intermediate, and dark fibers in the deep portion; and intermediate fibers with scattered dark fibers in the superficial portion. Transverse diameters varied among fibers in different portions of the quadriceps. These findings must be considered in experiments of muscle or motor endplates in hamster quadriceps muscle.

Animals↗
PubMed1980

Phasic tongue movements in human rapid eye-movement sleep.

Polygraphic recordings demonstrated complex tongue movements as unusual phasic phenomena during rapid-eye-movement (REM) sleep in patients with narcolepsy, sleep apnea syndrome, or posterior fossa lesions, and in normal controls. These tongue movements may counteract posterior displacement of the tongue to prevent obstructive sleep apnea, which may otherwise occur in REM sleep because of genioglossal hypotonia. Hypotonia affected not only the genioglossus but also other muscles innervated by pontomedullary neurons during non-REM-sleep-related apnea in patients with sleep apnea syndrome.

Adult↗
PubMed1980

Use of the respiratory magnetometer in diagnosis and classification of sleep apnea.

Seventeen patients with sleep apnea were studied with reference to the frequency and duration of apneic episodies, the mechanism of the apnea and the extent to which oxygen saturation was depressed by the apnea. In all patients, esophageal pressure was recorded simultaneously with respiratory magnetometer records of rib cage and abdominal motion. Thermistor records from the nose and mouth indicated the presence of apnea. Nine patients had purely obstructive apnea and eight a mixture of central and obstructive apnea. In all instances the magnetometer records alone permitted distinction between obstructive and central apnea. Inspiratory efforts against an occluded airway produced a very different pattern of motion when compared to unobstructed breathing or to central apnea. We propose that magnetometer monitoring of thoracoabdominal motion indicates upper airway obstruction reliably and provides a noninvasive and thus more acceptable alternative to esophageal pressure recording for detecting upper airway obstructive apnea.

Airway Obstruction↗