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Biomedical subjects

S Wadhwa

Publications and source records attributed to S Wadhwa.

At least 73 records · Page 4Linked to original sources
PubMed1988

Numerical estimates of GABA immunoreactive neurons in the human lateral geniculate nucleus in the prenatal period.

Quantitative analysis has been performed on Nissl stained and gamma-aminobutyric acid (GABA) immunoreactive neurons in the lateral geniculate nucleus (LGN) of human fetuses ranging from 8 to 37 weeks of gestation. Total cell density in the LGN increases from 8 to 12 weeks of gestation with a subsequent decline continuously up to 37 weeks. No GABA immunoreactive neurons are visualized in the LGN of 8 and 12 weeks fetuses. At 15-16 weeks of gestation 1% of neurons are immunostained. A peak rise is seen to occur at 17 weeks when 16% cells are GABA immunopositive. However, at 19 weeks there is an equally sharp decline in the percentage of GABA neurons to 4%. Subsequently, with the continued reduction in overall numerical density the percentage of GABA neurons remains relatively constant but rises again to 5% at 26 weeks. On making quantitative estimations of numerical density and percentage of GABA neurons separately for the prospective magno- and parvocellular regions in the early age periods from 15-16 to 21 weeks as well as at 22-23 weeks, when magnocellular laminae begin to segregate, and at 26 weeks when distinct laminae are present, it is observed that the magnocellular regions have a higher density and percentage of GABA neurons at all the gestational ages in comparison to the parvocellular region. With increasing gestational age, non-GABA neurons gradually increase in size with marked growth of magnocellular neurons at 26 weeks. The GABA neurons, on the other hand, have an almost constant size up to 19 weeks and start growing from 21 weeks onwards. The GABA neurons tend to be larger in the magno- than in parvocellular regions at all gestational ages studied.

Cell Count↗
PubMed1987

The influence of age and gender on normal appendicectomy rates.

Epidemiological data from a retrospective analysis of 1307 pathology reports of appendicectomy specimens from four Hunter Valley Hospitals, having a 100% tissue audit, showed that there was a significant difference in normal appendicectomy (histologically normal appendix following appendicectomy for suspected acute appendicitis) rates for the young (male and female 0-12 years) and reproductive female (13-50 years) groups when compared with the elderly (over 60 years) and the rest (male 13-59, female 51-59 years) of the population. The overall normal appendicectomy rate was 26%, and the perforation rate 3.6%. These data suggest that suspected acute appendicitis in the Hunter Valley is managed in an appropriate way. The perforation rate was significantly higher in the elderly group, and management of these patients will remain a problem due to delayed and atypical presentation. Continuing audit programmes and area-wide review should contribute to improved accuracy in the diagnosis of acute appendicitis.

Adolescent↗
PubMed1986

Ultrastructure of marginal zone during prenatal development of human spinal cord.

Electron microscopic studies were conducted in the marginal zone (lamina I) in human fetuses ranging from 8-25 weeks of gestational age. At 8 weeks the neurons have indented nuclei and sparse organelles in the cytoplasm. The neuropil shows contacts between the axons and dendritic profiles. Some of them are well defined synapses with post synaptic thickening and agranular spherical vesicles in the presynaptic terminal. At 18 weeks compactly packed organelles with long cisternae of rough endoplasmic reticulum could be visualized in the neuronal cytoplasm. At 25 weeks the neurons have heterochromatin patches in the nuclei. Axosomatic, dendrodendritic, axoaxonic, symmetrical, asymmetrical and multisynaptic contacts with agranular and dense core vesicles are seen at different sequential age periods.

Axons↗
PubMed1986

Role of oxygen radicals in ischemia-induced lesions in the cat stomach.

Ischemia in a stomach that contains acid may produce severe gastric mucosal injury. The extent to which oxygen-derived free radicals are involved in the pathogenesis of this injury was investigated in the present study. Local gastric ischemia was achieved by reducing celiac artery pressure to 30 mmHg for 1 h. Ischemic injury was assessed by recording the loss of 125I-albumin and 51Cr-red cells across the gastric mucosa. Cats were treated with a xanthine oxidase inhibitor (allopurinol), a superoxide radical scavenging enzyme (superoxide dismutase), and a scavenger of hydroxyl radicals (dimethyl sulfoxide). The damage associated with ischemia only occurred during reperfusion of the stomach and was worst in the antrum. The level of xanthine oxidase in the antrum was twice that of the corpus. Treatment with allopurinol, superoxide dismutase, and dimethyl sulfoxide reduced 51Cr-red cell loss to 15%, 25%, and 21% of control (untreated) animals, respectively. The data indicate that oxygen-derived free radicals play a role in ischemic injury to the stomach and that the hydroxyl radical, a secondary radical produced from the superoxide anion, appears to be the major oxygen radical contributing to ischemic damage.

Allopurinol↗
PubMed1985

Immunohistochemical localization of GABAergic cells in the developing human dorsal lateral geniculate nucleus.

GABAergic neurons were demonstrated in the dorsal lateral geniculate nucleus (dLGN) of human foetuses of 21 weeks gestation using unlabelled antibodies against gamma-aminobutyric acid (GABA). These inhibitory neurons are thus cytochemically identifiable prior to appearance of lamination, at a period when there is reportedly segregation of retinal afferents from both eyes and formation of morphologically defined synapses. Their presence in the prenatal period indicates that the morphological substrate responsible, in part, for the orientation sensitivity of the dLGN neurons exists before birth in man.

Geniculate Bodies↗
PubMed1985

Superior sagittal sinus thrombosis after closed head injury.

A case of superior sagittal sinus thrombosis after a closed head injury is presented along with a review of 11 other reported cases. Review of the literature indicates that this condition is rarely recognized and that further investigation is necessary to define the incidence, prognostic factors, and optimal therapy of this condition.

Adult↗
PubMedDate not supplied

Microbial contamination of weaning foods.

A survey was conducted to determine the prevalence rate of Escherichia coli in different foods being fed to children in the weaning age group. The samples were collected from middle income group (MIG) and high income group (HIG) houses in different localities in Chandigarh. A total of 530 MIG and 525 HIG houses were selected on the basis of availability of children in the weaning age group. A total of 2,016 samples of weaning foods were collected. Isolation of Escherichia coli from MIG and HIG houses was 66.75% and 8.5% respectively. Enterotoxigenic Escherichia coli were detected in 61.47% and 43.5% of the total Escherichia coli isolates from MIG and HIG houses respectively. 'O' serogrouping of the isolates was done and the predominant serotypes found were 06, 0106, 043, 057, 01. The laboratory studies showed that almost all weaning food samples prepared in the laboratory supported the growth of known enterotoxigenic Escherichia coli.

Child, Preschool↗
PubMedDate not supplied

Expression of GABA in the fetal, postnatal, and adult human retinas: an immunohistochemical study.

The expression of GABA in the human fetal (12-25 weeks of gestation), postnatal (five-month-old), and adult (35-year-old) retinas was investigated by immunohistochemistry. GABA expression was seen as early as 12 weeks in the undifferentiated cells of the inner neuroblast zone; a few optic nerve fiber layer axons were clearly labeled, suggesting that some of the stained cell bodies were prospective ganglion cells, others could be displaced amacrine cells. From 16-17 to 24-25 weeks, intense labeling was found in the amacrine, displaced amacrine, and some ganglion cells. During this time period, horizontal cells (identified by calbindin immunohistochemistry), undergoing migration (periphery) and differentiation (center), expressed GABA prominently. In the postnatal retina, some horizontal cells were moderately labeled, but very weakly in a few cells, in the adult. The Müller cells developed immunoreactivity first weakly at 12 weeks and then moderately from 16-17 weeks onward. The staining was also evident in the postnatal and adult retinas, showing labeled processes of these glial cells. Virtually no axons in the adult optic nerve and nerve fiber layer were stained; the staining was restricted to a few, large ganglion cells and displaced amacrine cells: Some amacrines were also labeled. The possibility that GABA might play a role in horizontal cell differentiation and maturation is highlighted. Other evidences suggest that GABA might play a role in metabolism during retinal development.

Adult↗