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Biomedical subjects

M Gupta

Publications and source records attributed to M Gupta.

At least 433 records · Page 24Linked to original sources
PubMed1982

Morphometric analysis of the visceral yolk sac endoderm in the rat in vivo and in vitro.

Rat embryos together with their visceral yolk sac were grown in vitro during the early period of organogenesis from days 9.5 to 11.5 and the ultrastructural morphology od the visceral yolk sac cells was compared with that in vivo at the beginning and at the end of the culture period. Identical areas of the visceral yolk sac endodermal cells were analysed morphometrically. A measure of the functional activity was obtained by comparison of the volume density of surface density of the vacoular system. At 9.5 and 11.5 days, the values obtained were virtually identical for yolk sacs in vivo and in vitro. At 9.5 days, the volume and surface density of the endocytotic vacuoles in the embryonic endoderm was significantly lower than in the visceral yolk sac endoderm. It is concluded that the digestive function of the yolk sac is almost certainly identical in culture and in vivo and that the cells of the embryonic endoderm do not take a significant part in embryonic nutrition.

Animals↗
PubMed1982

Dose-dependent induction of embryonic abnormalities in vitro by tissue homogenates of placenta and decidua.

Homogenate preparations from normal rat placental and decidual tissue induced abnormalities when included in the culture medium of rat embryos between Day 9.5 and Day 11.5. Abnormal embryos were produced between doses of 2.5 and 4 mg/ml for the placental homogenate and between doses of 1.2 and 4 mg/ml for the decidual homogenate, but were not produced by a solution of bovine serum albumin or by a protein preparation of rat lung tissue at the same concentration. The degree to which the embryos were malformed depended on the dose and which of the two homogenates was used. The decidual homogenate preparation was more pathogenic than the placental homogenate, but both were able to produce neural-tube defects and a severe reduction in embryonic size. The possible association between these findings and some known proteins within such homogenates is discussed.

Abnormalities, Drug-Induced↗
PubMed1981

Sequence analysis of the DNA encoding the Eco RI endonuclease and methylase.

The Eco RI endonuclease and methylase recognize the same hexanucleotide substrate sequence. We have determined the sequence of a fragment of DNA which encodes these enzymes using the chain-termination method of Sanger (Sanger, F., Nicklen, S., and Coulson, A. R. (1977) Proc. Natl. Acad. Sci. U. S. A. 74, 5463-5467). The amino acid sequences of both enzymes were derived from the DNA sequence. The coding regions selected include the only open translational frames of sufficient length to accommodate the enzymes. They coincide with previously established gene boundaries and orientation. The predicted amino acid sequences correlate well with analyses of the purified protein. Comparison of the nucleotide and protein sequences reveals no homology between the endonuclease and methylase which might provide insight into the origin of the restriction-modification system or the mechanism of common substrate recognition. Based on secondary structure predictions, the two enzymes also have grossly different molecular architecture. The base composition of the sequence is 65% A + T, and the codon usage is significantly different from that observed in several Escherichia coli chromosomal genes. In some cases, frequently selected codons are recognized by minor tRNA species. A spontaneous mutation in the endonuclease gene was isolated. Serine replaces arginine at residue 187. In crude extracts, Eco RI specific cleavage is approximately 0.3% wild type.

Amino Acid Sequence↗
PubMed1981

Ovarian steroidogenesis and development of fetuses following ochratoxin A treatment in pregnant rats.

Administration of ochratoxin A to pregnant rats from 6 to 12 days of gestation period, resulted in complete resorption of fetuses. On histological examination luteal degeneration was observed along with reduction in the weight of corpus luteum (mg/100 mg ovarian tissue) and pituitary gland. The enzyme delta 5-3 beta-hydroxy steroid dehydrogenase (delta 5-3 beta-OHD) and glucose-6-phosphate dehydrogenase were demonstrated histochemically in the ovary of pregnant rats. The activities of the enzymes were suppressed significantly in ochratoxin A treated rats. The same treatment also resulted in an accumulation of cholesterol and ascorbic acid in the ovary. Based on these results, it is suggested that resorption of fetuses in ochratoxin A treated rats may be related with a diminution in ovarian steroidogenesis possibly due to reduction in pituitary gonadotrophin secretion.

3-Hydroxysteroid Dehydrogenases↗
PubMed1981

Severe Escherichia coli septicemia mimicking necrotizing enterocolitis.

Enteropathogenic and nonenteropathogenic strains of Escherichia coli have been impicated as causative agents in necrotizing enterocolitis (NEC). The case presented here illustrates an example of fulminant E coli infection in an infant who manifested signs and symptoms of NEC without developing bowel damage.

Diagnosis, Differential↗
PubMed1980

Onset of puberty and ovarian steroidogenesis following administration of ochratoxin A.

The present experimental design was set up to examine the effect of Ochratoxin A on the onset of reproductive maturity and the ovarian steroidogenic capacity by means of histochemical studies. Ochratoxin A treatment causes a remarkable delay in sexual maturation as evidenced by the age at vaginal opening and appearance of first estrus (cornifid smear). The same treatment also results in a significant diminution of the delta 5-3 beta-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase activity along with a reduction in the weight of ovary, uterus, and pituitary. On the basis of above data it is assumed that the probable cause of delayed maturation in Ochratoxin A treated rat is due to the suppressed ovarian steroidogenesis.

3-Hydroxysteroid Dehydrogenases↗
PubMed1980

Histochemical determination of adrenal steroidogenesis in rat after treatment with ochratoxin A.

The enzymes delta 5-3 beta-hydroxy steroid dehydrogenase and glucose-6-phosphate dehydrogenase were demonstrated histochemically in the adrenal cortex of female rats. The activities of these enzymes were increased significantly in ochratoxin A treated rats along with an increase in the weight and reduction in cholesterol and ascorbic acid content of the gland. The observations suggest that after treatment with ochratoxin A, adrenal steroidogenesis was stimulated.

3-Hydroxysteroid Dehydrogenases↗
PubMed1980

Relationship between ABO blood groups and malaria.

A total of 736 patients with fever was tested for malaria and classified according to ABO blood group. Of these, 476 cases had patent parasitaemia at the time of investigation. The distribution of blood groups in this group was significantly different from that in 1300 controls from the same area. While group A was found to be more common in malaria cases than in normals, the reverse situation was found for group O. Possible explanations for this are discussed.

ABO Blood-Group System↗
PubMed1979

Application of ferrokinetic investigation for differential diagnosis in bone marrow hypoplasia and their clinical relevance.

In this study, erythropoietic activity of bone marrow has been evaluated by ferrokinetics. For that purpose, the data of radioiron disappearance from plasma and its ultimate incorporation in red blood cells after the injection of about 10 muCi of 59Fe tagged autologous plasma, were analysed and fitted to the sum of three exponentials, using a non-linear least square SAAM-25 program on UNIVAC-1108 computer. A function representing time-activity relationship, was constructed. The functional physiological model of iron metabolism, proposed by Cavill and Ricketts, was used to calculate various ferrokinetic parameters in terms of coefficients and exponents of the time-activity function. After identifying the parameters that could be used as indices of erythropoietic activity of bone marrow, the study was repeated in six patients after they had undergone myelostimulative therapy. A distinct correlation was found between ferrokinetic observations and clinical and biochemical findings. It has been demonstrated that in histologically diagnosed cases with bone marrow hypoplasia, a further differentiation between pure aplasia and those with hypoplasia together with ineffective erythropoiesis was possible. This discrimination which is clinically very important, is only possible by means of kinetic investigations.

Adult↗