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Biomedical subjects

R Singh

Publications and source records attributed to R Singh.

At least 631 records · Page 35Linked to original sources
PubMed1985

Inhibition of D-glucose uptake by isatin in rat intestine: effect of harmaline and various sulfhydryl reagents.

The effect of isatin (indole-2,3-dione) on D-glucose uptake has been studied in rat intestine. Isatin at 6 mM concentration significantly inhibited both the sugar uptake and transmural (mucosal to serosal side) transport in the intestine. The suppression of glucose uptake by isatin was irreversible. Similar to the action of various SH-group-reacting agents, isatin inhibited the sugar uptake, presumably by binding to membrane sulfhydryl groups through a covalent linkage. Isatin-induced reduction in glucose uptake was unaffected by pH (between 5.5 and 8.4) and by DTT addition to incubation medium. Inhibition of sugar uptake by isatin and harmaline was additive in nature; this suggested that these compounds interact at different sites on the microvillus membrane surface.

Alkaloids↗
PubMed1985

Pathologic pulmonary findings in children with the acquired immunodeficiency syndrome: a study of ten cases.

Lung tissue and tissue from the lymphoreticular system obtained at open biopsy and/or autopsy were studied in ten children with the acquired immunodeficiency syndrome (AIDS). One or both parents of nine of the children had AIDS or risk factors for AIDS. The remaining child had hemophilia. The following pulmonary lesions were seen: 1) diffuse alveolar damage (DAD), 2) Pneumocystis carinii and/or cytomegalovirus pneumonitis, 3) lymphoid interstitial pneumonitis (LIP), and 4) desquamative interstitial pneumonitis (DIP). Combinations of such factors as mechanical ventilation, oxygen therapy, and opportunistic infection played a role in the pathogenesis of DAD. Opportunistic infections were related to the defective cell-mediated immunity in these children. The clinical, epidemiologic, immunologic, and pathologic features of the thymuses of these patients indicate that the immune deficiency was unlikely to have been of congenital origin. The immunologic abnormalities may also have been related to the pathogenesis of LIP and DIP. Neither LIP nor DIP has been described in adults with AIDS. Open lung biopsy is of practical importance in the diagnosis and treatment of pulmonary disease in children with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Role of the posterior capsule in the prevention of postoperative bacterial endophthalmitis: experimental primate studies and clinical implications.

The posterior capsule has an important effect on the risk of postoperative bacterial endophthalmitis. In order to investigate whether the posterior capsule inhibited the spread of infection into the vitreous we performed extracapsular cataract extraction in both eyes of 10 primates. In one eye of each primate the posterior capsule was left intact and in the other eye a large posterior capsulectomy was performed. When the anterior chambers were challenged with equivalent inocula of Staphylococcus aureus, one of 10 eyes with an intact posterior capsule developed culture-positive vitreous infection. In contrast, nine of 10 eyes with a large posterior capsulectomy developed culture-positive vitreous infection. In a second experiment we investigated the effect of an intraocular lens on the barrier effect. Ten primates received extracapsular cataract extraction in both eyes and pseudophakic implantation. In one eye of each primate the posterior capsule was left intact and a J-loop monoplanar lens was implanted in the ciliary sulcus. In the other eye of each primate a large posterior capsulectomy was followed by implantation of a monoplanar, non-vaulted pseudophakos into the anterior chamber. None of the 10 eyes with a posterior capsule intact and a posterior chamber lens in place developed positive vitreous cultures or histopathological evidence of vitreous infection. Thus the presence of a posterior chamber lens did not appreciably compromise the barrier effect of the intact posterior capsule. 40% of the eyes with a large posterior capsulectomy and a non-vaulted pseudophakos in the anterior chamber developed culture-positive vitreous infection, and 60% of the eyes showed histopathological evidence of vitreous infection.

Animals↗
PubMed1985

Effect of short-term and long-term treatment with a steroidal oral contraceptive on the intestinal absorption of nutrients in vitro in female rats.

The effect of steroidal oral contraceptive (SOC), comprising megestrol acetate (5 mg/kg body weight) plus ethinyl estradiol (0.05 mg/kg body weight), administered daily by stomach tube for 5, 15, 30 and 90 days, on the intestinal uptake of nutrients such as glucose, amino acids and calcium has been investigated in vitro in female rats. The administration of SOC for 5 days did not affect the uptake of nutrients, but treatment for 15, 30 and 90 days led to a progressive and significant increase in the uptake of glucose and amino acids. The calcium uptake was increased in the groups treated for 5 and 15 days, but decreased after 30 and 90 days of treatment. Kinetic studies done on glucose uptake indicated that the steroid contraceptive might be inducing the transport carrier protein of this nutrient, as elevation in Vmax was observed in the group treated for 30 days. There was no change in brush border membrane phospholipid and cholesterol contents after 30 and 90 days of treatment, but a significant increase in phospholipid after 5 and 15 days of treatment was observed. This study suggests that SOC treatment significantly altered the intestinal absorptive functions and the effect appears to be on the carrier-mediated transport of glucose.

Amino Acids↗
PubMed1985

Serum copper in myocardial infarction--diagnostic and prognostic significance.

Serum copper estimations were carried out in 44 cases of acute myocardial infarction, 23 cases of angina and 40 age and sex matched healthy controls. A highly significant degree of rise in serum copper levels was observed in patients with acute myocardial infarction as compared to cases of angina and controls. The levels showed a gradual rise with peak on 7th day followed by a gradual decline returning to normal on 28th day. The pattern was the same both in complicated and uncomplicated cases except that values were still higher on the 28th day in complicated cases of acute myocardial infarction. Mean peak serum copper levels were significantly higher (p less than .001) in complicated cases of acute myocardial infarction as compared to uncomplicated cases. Significant correlation was found between serial serum copper changes and creatinine phosphokinase and lactic dehydrogenase levels. The prognostic and diagnostic significance of serum copper has been discussed.

Adult↗
PubMed1985

Effect of a steroidal oral contraceptive on intestinal absorptive functions in proteins deficient rat.

The effects of steroidal oral contraceptive norethynodrel plus ethinylestradiol-3-methyl ether (SOC) at a daily dose of 5 mg: 0.06 mg per kg body weight for 28 days on intestinal absorptive functions have been investigated in protein-deficient female albino rats. The administration of this contraceptive caused significant increase in glucose and amino acids uptake but had no effect on calcium and zinc uptake in pair-fed as well as in protein-deficient rat. Further studies carried out on glucose transport system showed that the transport of sodium-dependent glucose was significantly enhanced while that of sodium-independent glucose remained unaltered in drug-treated animals. Kinetic studies of glucose transport in the presence of sodium ions revealed that SOC treatment affected the rate of uptake of glucose by elevating Vmax, but the apparent Kt value remained the same in treated and untreated animals.

Amino Acids↗
PubMed1985

Response of the cockroach brain gamma-aminobutyric acid system to isonicotinic acid hydrazide and mercaptopropionic acid.

The presence of gamma-aminobutyric acid (GABA) as well as glutamic acid decarboxylase (GAD) and GABA-transaminase (GABA-T) enzymes was demonstrated in the cockroach (Periplaneta americana) brain. Isonicotinic acid hydrazide (INH) in vivo (2.19 mumol/g) inhibited brain GAD activity, the inhibition lasted for about 2 hours and the normal activity levels reappeared at 4 h after INH administration. Brain GABA levels increased initially but then declined and were restored to normal levels at 4 h after INH administration. GABA-T activity was strongly inhibited by INH and a total 100% inhibition was observed at 2-3 h following INH treatment. The GABA-T activity, however, began to recover after 3 h but only 37% of the total enzyme activity was released from inhibition. Mercaptopropionic acid (MPA) in vivo (32 micrograms/g) inhibited brain GAD activity and depleted GABA level also. Results indicate that INH response of the cockroach brain GABA system is similar to that reported for the chick brain but differs from that of the mammalian brain.

3-Mercaptopropionic Acid↗
PubMed1985

Ultimobranchial gland structure in some species of squamata.

Calotes versicolor has single gland on the left side in neck region, just anterior to heart, while Ptyas mucosus and Bungarus caeruleus have 2 equal-sized glands located in the thyro-thymic region. The gland was spheroidal and measured 0.5 to 1.5 mm in diameter. Size of the gland varied individually in relation to the body size. The gland was composed of cell masses and follicles, and was well vascularized. Histology of the gland showed marked individual variation. Ciliated and goblet cells were present.

Animals↗
PubMed1985

Effects of 17 beta-estradiol and progesterone on intestinal digestive and absorptive functions in ovariectomized rats.

The effects of low and high doses of 17 beta-estradiol and progesterone for 2 weeks on intestinal digestive and absorptive functions have been investigated in ovariectomized rats. The uptake of glucose was significantly enhanced following ovariectomy and administration of hormones restored the level of glucose uptake to that observed in sham-operated animals. Neither, the uptake of L-leucine nor calcium was affected after ovariectomy and treatment with the hormones. The activity of alkaline phosphatase (AP) of ileum was significantly elevated with the low and high doses of 17 beta-estradiol but in jejunum only at high doses. Progesterone alone did not alter AP activity but the combination of this hormone and 17 beta-estradiol significantly enhanced the jejunal and ileal AP activities. It seems that activity of AP is mainly under the control of 17 beta-estradiol. The activity of ileal disaccharidases and leucine aminopeptidase were enhanced at high doses of 17 beta-estradiol alone or in combination with progesterone whereas in the jejunum only AP activity was increased significantly. The present study indicates that 17 beta-estradiol plays an important role in regulating the activities of intestinal digestive enzymes and it is the ileal enzymes which are more prone to its action.

Alkaline Phosphatase↗