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Biomedical subjects

S C Sharma

Publications and source records attributed to S C Sharma.

At least 307 records · Page 17Linked to original sources
PubMed1980

Specification of retinotectal connexions during development of the toad Xenopus laevis.

The specification of central connexions of retinal ganglion cells was studied in Xenopus laevis. In one series of experiments, the right eye primordium was rotated 180 degrees at embryonic stages 24-32. In the other series, the left eye was transplanted into the right orbit, and vice versa, with either 0 degrees or 180 degrees rotation. After metamorphosis the visual projections from the operated eye to the contralateral optic tectum were mapped electrophysiologically and compared with the normal retinotectal map. In all cases the visual projection map was rotated through the same angle as was indicated by the position of the choroidal fissure. The left eye exchanged into the right orbit retained its original axes and projected to the contralateral tectum. These results suggest that retinal ganglion cell connexions are specified before stage 24.

Animals↗
PubMed1979

Tectal projections in the goldfish (Carassius auratus): a degeneration study.

Efferents revealed by degeneration staining following tectal lesions in goldfish are presented. Four major projections were found. Ascending ipsilateral projections to pretectal-diencephalic areas exit the tectum rostrally and laterally and terminate in the area pretectalis (AP), lateral geniculate (LGN), nucleus pretectalis (NP), and nucleus rotundus (NR). Ascending contralateral projections exit rostrally and possibly laterally, enter the posterior and postoptic commissures and terminate in the contralateral AP, LGN, NP, NR, and rostral tectum. A medially directed projection enters the intertectal commissure, and some of these fibers may terminate sparsely in an area of the contralateral tectum homotopic to the lesion. A descending projection exits the tectum laterally and projects ipsilaterally to a dorsolateral tegmental nucleus (DLT) and the lateral reticular formation of the tegmentum and pons, and contralaterally to the medial reticular formation of the tegmentum and pons.

Animals↗
PubMed1979

An iridium-192 mold for use in treating carcinoma of the soft palate.

A Lucite sandwich mold containing Iridium-192 wire for use in the treatment of soft palate carcinoma is described. This mold is very simple to use, produces a homogeneous (+/- 10%) radiation field across the midplane of the tumor, and requires minimal machinist time.

Brachytherapy↗
PubMed1978

Platelet adhesiveness, plasma fibrinogen, and fibrinolytic activity in young patients with ischaemic stroke.

Cerebral thromboembolic stroke in the young is uncommon. Disturbances in the n ormally existing dynamic equilibrium between coagulation and fibrinolysis may play a major role in the pathogenesis of such episodes. In a search for a possible hypercoagulable state platelet adhesiveness by the method of Eastham, plasma fibrinogen and euglobulin clot lysis times were estimated in 46 patients. A group of 15 normal subjects matched for age and sex were also studied for comparison. Significant increase in platelet adhesiveness (P less than 0.001) and plasma fibrinogen (P less than 0.001) was noted in the patients when compared with the normal subjects. Absence of corresponding increases in fibrinolytic activity in the patients suggests disturbed equilibrium between coagulation and fibrinolysis. The possibility of a hypercoagulable state in these cases is discussed.

Adult↗
PubMed1978

Urinary catecholamine excretion in temporary residents of high altitude.

Urinary catecholamine excretion was estimated in 50 lowlanders temporarily staying at altitudes above 3,000 m. They were divided in subgroups according to the length of their continuous stay. For comparison, 25 highlanders who were born and brought up at high altitude and 50 lowlanders who had never been to altitudes of more than 1,000 m were also studied. High catecholamine excretion was noted in temporary residents staying at high altitude for up to 30 days as compared to that in lowlanders (P greater than 0.01). The excretion rate gradually returned to basal values thereafter. Catecholamines were essentially similar in lowlanders and highlanders. The significance of these findings is discussed regarding the possible pathogenetic role of the sympathoadrenal system in the development of ill effects in respone to high-altitude exposure.

Adult↗