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Biomedical subjects

S Sehgal

Publications and source records attributed to S Sehgal.

298 records · Page 17Linked to original sources
PubMedDate not supplied

Maturation, capacitation, and metabolism of goat spermatozoa using magnetic resonance methods.

The ability of intact cells to reduce spin labels has been utilized to characterize the activity of spermatozoa of goat. The kinetics of reduction of TEMPO has been found to be sensitive to the quantity, quality and state of epididymal maturation of the spermatozoa. Presence of alcohol caused activation and Gossypol acetic acid left sperm activity unaltered. Electron spin resonance (ESR) and 31P Nuclear magnetic resonance (NMR) indicate that the period of in vitro capacitation requires optimization. 31P NMR spectra indicate a good correlation with the progressive maturation of the cells.

Animals↗
PubMedDate not supplied

Cystic disease of the liver following prenatal and perinatal exposure to aflatoxin B1 in rats.

Experiments were designed to elucidate the differences, if any, in the liver histology induced by aflatoxin B in newborn and adult animals. The transfer of toxic metabolites from pregnant rats to their litters was confirmed by thin layer chromatography of liver homogenates in the latter. Extensive cystic lesions of the biliary and hepatic type developed only in young animals. Multifocal hepatic necrosis, bile ductular proliferation, areas of altered hepatocytes, neoplastic nodules and hepatocellular carcinoma constituted the total spectrum in both adult and newborn animals. Increased susceptibility to the toxins early in life appears to be responsible for this intriguing phenomenon. These aspects may have a bearing on the genesis of childhood liver disease.

Aflatoxin B1↗
PubMedDate not supplied

Polymer-coated liposomes: improved liposome stability and release of cytosine arabinoside (Ara-C).

Liposomes of dimyristoylphosphatidylcholine (DMPC) or dipalmitoylphosphatidylcholine (DPPC), cholesterol (CHOL) and dicetylphosphate (DCP) containing Ara-C were prepared at pH 4.5 and subsequently coated with a derivatized polysaccharide, O-palmitoylpullulan (OPP). Encapsulation efficiencies (EEF) of DMPC:CHOL:DCP (3:1:2 mol ratio) and DPPC:CHOL:DCP (3:1:0.5 mol ratio) liposomes were respectively 28 and 40% before and 15 and 27% after coating with polymer. Stabilities of liposomes in sodium cholate (SC) concentrations up to 16 mM at pH 5.6 or in SC solutions at pH 7.4 were increased by coating with OPP. At pH 2.0 and 37 degrees C, Ara-C was released at a slow rate, kuo (uncoated) or kco (coated), for 24 h after an initial rapid release phase that lasted for about 6 h and the ratio kuo/kco, was 1.9 and 5.7 for the DMPC:CHOL:DCP and the DPPC:CHOL:DCP compositions respectively. At pH 7.4 and 37 degrees C in the presence of 10 mM SC, the ratio kuo/kco was 5.1 and 1.4 respectively. It is concluded that coating liposomes with OPP increases the potential of using liposomes as a drug delivery system in harsh environments such as encountered after oral administration, although the magnitude of the effect is dependent on the liposome composition.

1,2-Dipalmitoylphosphatidylcholine↗
PubMedDate not supplied

Immunogenicity of deglycosylated zona pellucida antigens and their inhibitory effects on fertility in rabbits.

Influence of carbohydrates on the immunogenicity and immunocontraceptive potential of zona pellucida glycoproteins has been investigated in rabbits. Porcine zonae pellucidae, following deglycosylation with trifluoromethane-sulfonic acid, retained significant immunogenic potential, as shown by the ability to generate antibodies which cross-reacted with the heterologous antigen. Antibody response, however, was much stronger against the native zona glycoproteins, thereby suggesting that both carbohydrate and protein moieties contribute to the overall immunogenicity of the zona pellucida antigens. Contraceptive efficacy of active immunization with the deglycosylated zona antigens, when evaluated by mating experiments, demonstrated inhibition of fertility in all immunized rabbits. Normal ovarian functions were disrupted in these animals, as revealed by the reduction in ovarian weights and gross impairment of folliculogenesis. Flushing of the oviducts of the immunized animals yielded a markedly reduced number of ova ovulated in response to hCG administration, none of which were fertilizable. Results collectively suggest that active heteroimmunization with deglycosylated zona pellucida antigens is effective in reducing fertility in rabbits.

Analysis of Variance↗
PubMedDate not supplied

Renovascular hypertension due to Takayasu's arteritis among Indian patients.

Over a 16-year period, 205 patients with hypertension were shown to have a renovascular aetiology. Of these, 125 (61 per cent) had Takayasu's arteritis, 58 (28.3 per cent) had fibromuscular dysplasia, 16 (7.8 per cent) had atherosclerosis, five (2.4 per cent) had polyarteritis nodosa and one (0.5 per cent) had renal artery aneurysm. Among patients with Takayasu's arteritis, males were affected as commonly as females. The mean age of these patients at the time of detection was 26.8 +/- 8.6 years (range 5-52 years). Type I arteritis was seen in nine (7.2 per cent), Type II in 40 (32 per cent) and Type III in 76 (60.8 per cent) patients. The abdominal aorta was involved in 117 (93.3 per cent) patients. Takayasu's arteritis was associated with ulcerative colitis in two patients and with renal amyloidosis and focal segmental glomerulosclerosis with a nephrotic syndrome in one patient each. Surgical intervention consisting of bypass procedures, autotransplantation or nephrectomy was performed in 17 (13.6 per cent) and angioplasty in nine (7.2 per cent) patients. Cure and improvement in blood pressure was observed in 82.4 per cent and 77.8 per cent respectively. Adequate control of blood pressure was achieved with drugs only in 22 (22.2 per cent) patients. A definite cause and effect relationship could not be established between any infective or immunological disorder and Takayasu's arteritis. Takayasu's arteritis is a far more common cause of renovascular hypertension in Indian population than fibromuscular dysplasia or atherosclerosis, which are more common in the western population.

Adolescent↗
PubMedDate not supplied

Studies on victims of bite by a dog in Delhi.

Ninety persons were bitten by a single rabid dog on 23rd January, 1992 in Central Delhi area. All patients were given immediate first-aid, prophylactic tetanus toxoid injection and post-exposure antirabies treatment i.e., hyperimmune antirabies serum (ARS) and antirabies vaccination in different Hospitals of Delhi. Fifteen (15) patients received tissue culture antirabies vaccine (Rabipur or Verorab) and rest 75 patients were given nervous tissue vaccine. ARS was given to all patients as all had severe (Class-III) bite. Altogether there were 76 male and 14 female and 80 adult and 10 children bitten by the dog. All patients well tolerated the vaccines excepting a few, who developed very minor side-effects. Investigation regarding post-exposure antirabies antibody assessment were carried out in twenty-four patients at WHO Collaborative Centre for Rabies. Epidemiology for South-east Asia at National Institute of Communicable Diseases, Delhi. Paired blood samples were obtained from these patients and all of them had protective antibody titre (0.5 IU/ml) with mean titre of 1.81 IU/ml and 2.11 IU/ml in first and second samples, respectively. All patients were followed after six months and there were no death or vaccine failure reported.

Adult↗