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Biomedical subjects

N Singh

Publications and source records attributed to N Singh.

At least 577 records · Page 32Linked to original sources
PubMed1982

Trigeminal nerve stimulation: short latency somatosensory evoked potentials.

We have devised a technique to measure trigeminal somatosensory evoked potentials, stimulating the mentalis nerve at the mandibular foramen and recording the evoked early potential on the scalp at 3.2 msec. The early potential was easily recognized in all normal subjects and on the asymptomatic side of patients with facial pain. The latency of the early potential in normals was 1 to 2 msec less than half the latency of the mechanically induced jaw jerk. The early potential appeared simultaneously on both sides after stimulation of either the right or left mentalis nerve and may have its origin in deep brainstem structures, the Gasserian ganglion, or the trigeminal nerve. The technique is useful in documenting the functional integrity of peripheral and central afferent pathways of the trigeminal nerve.

Adult↗
PubMed1982

Characterization of the beta-adrenoceptors in coronary vasculature of the dog heart.

In the present study an attempt has been made to characterize the beta-adrenoceptors of coronary vasculature in dog. Blockade of beta 1-adrenoceptors with ICI 50172 or beta 2-adrenoceptors with RB2 showed only partial antagonism of isoprenaline-induced decrease in coronary resistance. However, combined treatment with ICI 50172 and RB2 completely blocked the isoprenaline-induced fall in coronary resistance. Essentially similar results were observed in controlled heart rate experiments where the drugs were administered locally into the coronary circulation. These results demonstrate the involvement of both beta 1 and beta 2 adrenoceptors in isoprenaline-induced coronary vasodilation.

Animals↗
PubMed1982

Epidemiology of Norwalk gastroenteritis and the role of Norwalk virus in outbreaks of acute nonbacterial gastroenteritis.

Outbreaks of Norwalk gastroenteritis, which may involve persons of all ages, occur during all seasons and in various locations. Waterborne, foodborne, and person-to-person modes of transmission have been described, and secondary person-to-person transmission is common. Outbreaks generally end in about 1 week; longer outbreaks occur only when new groups of susceptible persons are introduced, usually in the setting of a persistent common source of infection. The illness is generally mild and characterized by nausea, vomiting, diarrhea, and abdominal cramps. Vomiting is the predominant symptom among children, whereas diarrhea is commoner among adults. Forty-two percent of 74 outbreaks of acute nonbacterial gastroenteritis investigated by the Centers for Disease Control from 1976 to 1980 were attributed to the Norwalk virus. The rest resembled Norwalk outbreaks clinically and epidemiologically and were probably caused by 27-nm viral agents similar to the Norwalk virus.

Acute Disease↗
PubMed1982

Decreased lymphocyte aryl hydrocarbon hydroxylase and glutathione S-transferase activities in patients with hand dermatitis.

Aryl hydrocarbon hydroxylase (AHH) and glutathione S-transferase (GST) (EC 2.5.1.18) activity were measured in human lymphocytes of peripheral blood from 8 patients with irritant or allergic contact dermatitis of the hands, and compared with data from a control group. Both AHH and GST activity was found to be significantly depressed in the allergic and irritant contact dermatitis subjects, as compared with controls. It is suggested that AHH may be a quantitative marker of the inflammatory status.

Adult↗
PubMed1982

Acute viral enteritis and exacerbations of inflammatory bowel disease.

In order to determine whether or not acute viral gastroenteritis predisposes to exacerbations of inflammatory bowel disease, patients with Crohn's disease and ulcerative colitis were observed longitudinally. Assessment of disease activity was correlated with evidence for viral infection by serology and stool antigen testing. Disease exacerbations were rarely associated with rotavirus, Norwalk agent, or adenovirus infection, primarily because these infection rates were very low. However, the few patients having these viral infections often had relapse symptoms.

Acute Disease↗
PubMed1982

Vasopressin concentration in cord blood: correlation with method of delivery and cord pH.

Cord plasma vasopressin concentration, determined by radioimmunoassay, was higher in arterial than in venous blood in 122 (84%) infants; the highest vasopressin values were recorded in 21 acidotic infants (mean cord pH, 7.13) delivered per vaginam and the lowest values in 50 infants delivered by cesarean section. Cord vasopressin levels were not elevated in infants delivered by cesarean section because of obstructed labor. There was a lack of correlation between vasopressin levels and the length of labor or cervical dilatation; a significant correlation was found between cord arterial vasopressin values and pH. Low vasopressin values were recorded in a group of 22 healthy infants (mean cord pH, 7.29) delivered by low forceps operation.

Abruptio Placentae↗
PubMed1981

Mixed function oxidase and glutathione S-transferase activities in normal human peripheral blood lymphocytes.

The carcinogenic activity of some chemicals may be related to uncoupling of metabolism mediated by the mixed function oxygenase system. The intermediate formation of reactive epoxides or hydroxylamines may be eliminated by glutathione S-transferase. The ratio between these 2 enzymic activities may indicate if individuals are prone to cancerous development. If adequate cellular samples are available, assay of these enzymes may be used to trace individuals at risk. Therefore the present paper estimates these 2 enzymic activities (i.e., aryl hydrocarbon hydroxylase (AHH) and N-demethylation, the metabolite forming enzyme activities and glutathione S-transferase, the metabolite detoxifying enzymes), in the peripheral blood lymphocytes of 35 subjects. Their median age was 34 years. AHH activity was increased by 52% in the lymphocyte homogenate and by 45% in the microsomal fraction of smokers when compared with non-smokers. The enzyme activity also increased by 73% in the homogenate and by 93% in the microsomes of those taking drugs. The activity of N-demethylase increased by 212% in microsomes of smokers. However, the glutathione S-transferase activity decreased by about 2% in the lymphocyte homogenate and cytosol of smokers. The subjects taking drugs showed a decrease in this enzyme activity by 8% in the homogenate and by 37% in the cytosol.

Aryl Hydrocarbon Hydroxylases↗
PubMed1981

Symmetric sarcoid polyneuropathy: analysis of a sural nerve biopsy.

A 20-year-old woman with sarcoidosis had uveitis, subacute symmetric sensorimotor neuropathy, and noncaseous granulomas in biopsies of gastrocnemius muscle and sural nerve. Morphologic studies of the nerve confirmed the electrodiagnostic impression of an acute axonal and demyelinating neuropathy. Of 100 teased myelinated nerve fibers, 15% contained myelin ovoids and 24% demonstrated segmental demyelination. Quantitative analysis showed a reduction in the numerical density of myelinated fibers. By electronmicroscopy, unmyelinated fibers were largely spared. The exact mechanism of nerve fiber damage was not determined, but a local effect of the granuloma seemed likely, because most lesions were found in the endoneurium.

Adult↗
PubMed1981

Diaphragm pacing in spinal muscular atrophy: case report.

A patient with a diagnosis of intermediate or benign spinal muscular atrophy was severely incapacitated from respiratory complications and alveolar hypoventilation and was confined to mechanical ventilatory support. After extensive diagnostic evaluation of her pulmonary status, including transcutaneous stimulation of the phrenic nerves associated with nasogastric and surface electrode recording of the diaphragmatic response, this patient had a phrenic neurostimulation system implanted bilaterally for diaphragm pacing. Although spinal muscular atrophy has not been previously recognized as an indication for diaphragm pacing, her subsequent social, physical, and psychological improvement indicate that it may be significantly beneficial in selected cases of alveolar hypoventilation due to spinal muscular atrophy or neuromuscular disease.

Adolescent↗
PubMed1980

Juvenile muscular atrophy localized to arms.

Twenty-four patients from India, had juvenile muscular atrophy localized to the upper extremities. The condition characteristically affects young men and is not familial. Atrophy is limited to the hand and forearm muscles, with slow progression for two to three years after which it seems to be stationary. The condition is associated with "tremor-like" movements out of proportion to the weakness. Examination of muscle biopsy specimens shows group 2 fiber atrophy. This syndrome, for which no cause has been described, is benign and self-limiting, unlike most motor neuron diseases, and is distal in upper extremities, unlike Kugelberg-Welander disease. Asymmetrical muscle wasting and preceding febrile illness in some patients suggests an atypical poliomyelitis-like viral disease.

Adolescent↗