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Biomedical subjects

P Seth

Publications and source records attributed to P Seth.

At least 163 records · Page 9Linked to original sources
PubMed1992

Detection of human papilloma virus types 16 & 18 DNA in cervical lesions of Indian women using in situ hybridization.

Fifty one biopsies from women with malignant lesions of the uterine cervix and 9 biopsies fron non-malignant lesions were examined for the presence of HPV 16 and 18 DNA sequences by in situ hybridization method using 35S-labelled DNA probes. HPV 16 DNA sequences were detected in 82.4 per cent biopsies from women with malignant lesions, whereas HPV 18 DNA was detected in only 3 biopsies which were also positive for HPV 16 DNA. Two biopsies from non-malignant lesions were positive for HPV 16 DNA only. Data were also analysed according to the histologic type of cancer. It was observed that no significant correlation existed between HPV types and different histologic types of cervical cancer.

DNA Probes, HPV↗
PubMed1992

An epidemic of acute haemorrhagic conjunctivitis caused by coxsackie A24 variant.

An epidemic of acute haemorrhagic conjunctivitis (AHC) caused by a variant of coxsackie A24 (cox A24) occurred in Delhi during August to September 1988. Cox A24 antigen was detected by indirect immunofluorescence (IFA) in conjunctival cell smears of 13 of the 38 (34.2%) patients studied. Virus was isolated from conjunctival swabs in 11 (28.9%) patients and all isolates were neutralized by cox A24 antiserum. Five virus strains sent to Virology Division of Centres for Disease Control, Atlanta, USA, were confirmed as cox A24 variant. Enterovirus type 70 (EV70) was not demonstrable either by IFA or neutralization tests. Conjunctival swabs from 10 healthy laboratory controls did not show any evidence of EV70 or cox A24 virus or their antigens.

Acute Disease↗
PubMed1992

Prevalence of SSPE: a serological study.

The presence of measles antibodies in serum and cerebrospinal fluid (CSF) of 340 samples from children clinically suspected of subacute sclerosing panencephalitis (SSPE) were studied. One hundred and thirty eight (40%) of these children had SSPE based on the serological evidence. The mean age group of children affected was 8.2 years. The M:F ratio was 5:1. The titres of antibodies ranged from 1:2 to 1:32 in the CSF and from 1:16 to 1:512 in the serum.

Child↗
PubMed1992

Metabolic activation of sodium nitroprusside to nitric oxide in vascular smooth muscle.

Sodium nitroprusside (SNP) is thought to exert its vasodilating activity, at least in part, by vascular activation to nitric oxide (NO), but the activation mechanism has not been delineated. This study has examined the potential for vascular metabolism of SNP to NO in bovine coronary arterial smooth muscle subcellular fractions using a sensitive and specific redox-chemiluminescence assay for NO. SNP was readily metabolized to NO in subcellular fractions, and the dominant site of metabolism appeared to be located in the membrane fractions. NO-generating activity was significantly enhanced by, but did not absolutely require, the addition of a NADPH-regenerating system, NADPH per se, NADH or cysteine. A correlation analysis of NO-generating activity (in the presence of a NADPH-regenerating system) with marker enzyme activities indicated that the SNP-directed NO-generating activity was primarily membrane-associated. Radiation inactivation target-size analysis revealed that the microsomal SNP-directed NO-generating activity was relatively insensitive to inactivation by radiation exposure, suggesting that the functioning catalytic unit might be quite small. A molecular weight of 5 to 11 kDa was estimated. NO-generating activity could be solubilized from the crude microsomes with 3-[(3-cholamidopropyl)- dimethylammonio]-1-propane sulfonate, and the solubilized extract was subjected to gel filtration chromatography. NO-generating activity was eluted in two peaks: one peak corresponding to an approximate molecular weight of 4 kDa, thus confirming the existence of a small molecular weight NO-generating activity, and a second activity peak corresponding to a molecular weight of 112 to 169 kDa, the functional significance of which is unclear at present.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Conversion of nitroglycerin to nitric oxide in microsomes of the bovine coronary artery smooth muscle is not primarily mediated by glutathione-S-transferases.

The pharmacological action of organic nitrate vasodilators [e.g., nitroglycerin (NTG)] is thought to be mediated through metabolic conversion to nitric oxide (NO); conversion leads to vasodilatation, whereas diminished conversion in chronic therapy may lead to pharmacological tolerance. The biochemical nature of this process, however, is poorly understood. Glutathione-S-transferases (GST) have been shown to metabolize organic nitrates in the liver, but it is not known whether these enzymes are involved in this pharmacologically relevant process. We, therefore, compared the activities of conversion of NTG to NO vs. those of GST in microsomal suspensions of bovine coronary artery smooth muscle tissue. A classical GST substrate, 1-chloro-2,4-dinitrobenzene, inhibited NO production in microsomes, suggesting possible involvement of GST in organic nitrate activation. However, GST activity derived from microsomes exhibited a different heat lability profile compared to that of NO generation. Known inhibitors of GST (viz., indomethacin and bromosulfophthalein) did not alter the NO-generating activity in microsomes. Glutathione was a critical cofactor for GST, but not for NO generation from NTG, and thiols other than glutathione (e.g., N-acetyl-L-cysteine and thiosalicylic acid) also could facilitate NO production. Moreover, comparison to a commercially available purified liver GST preparation showed that, at the same GST activity toward 1-chloro-2,4-dinitrobenzene, the microsomal incubation produced about 8 times more NO than the purified liver GST. Radiation inactivation analysis of the functional molecular sizes of GST and the NO-producing enzyme(s) suggested that the enzymes were of different molecular weights (54 kD and 160 kD, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Recovery of human immunodeficiency virus from asymptomatic prostitutes from Tamil Nadu.

Peripheral blood mononuclear cells (PBMC) from 13 asymptomatic healthy human immunodeficiency virus type-1 (HIV-1) antibody positive prostitutes from Tamil Nadu, southern India, were cocultivated with phytohemagglutinin stimulated PBMC from HIV antibody negative donors for HIV isolation. In addition, plasma samples from two antibody positive prostitutes with HIV antigenemia were processed for virus isolation. The presence of virus in the cultures was monitored by (i) assay for virus particle associated reverse transcriptase (RT) activity, (ii) HIV-antigen enzyme immunoassay, and (iii) indirect immunofluorescence test to detect expression of HIV specific core antigens p-24 and p-17 in infected cells using monoclonal antibodies to these antigens. The virus was isolated from PBMC from 2 prostitutes (86-4 and 86-5) and from plasma of one prostitute (86-20). These isolates have been characterised as HIV type-1 by dot blot hybridization using HIV-1 and HIV-2 proviral DNA probes.

DNA, Viral↗
PubMed1991

HIV antibody screening of commercially available blood products in India.

In a screening of 182 vials of various commercially available blood products in the Indian market, 32 (17%) were found to contain HIV-1 antibodies. The contamination with HIV-1 antibodies was detected in all types of blood products including immunoglobulin preparations, cryoprecipitates as well as albumin. Interestingly, the contamination was seen almost exclusively in the products manufactured in the Bombay-Pune area (32 of 92, 34%). It was very low in products manufactured near Delhi (1 of 90). A single vial of imported Factor VIII concentrate tested negative.

Biological Products↗
PubMed1991

Circulating immune complexes in tuberculosis.

To examine whether any correlation exists between the levels of circulating immune complexes (CICs) and the activity of tuberculosis, CICs were measured in the sera of 75 patients with active tuberculosis and in 25 control subjects using polyethylene glycol method. The effect of drug treatment on the levels of CICs was also estimated in 25 patients. It was found that levels of CICs were elevated in most of the untreated patients (96%) of tuberculosis and the CICs levels fell to control values in 64% of patients at the end of treatment.

Antigen-Antibody Complex↗
PubMed1990

Acute rubella infection in pregnant women in Delhi.

Serum samples of 17 pregnant women with suspected rubella who presented at the Department of Microbiology, AIIMS, New Delhi, from March to May 1988 for confirmation of diagnosis were tested for rubella haemagglutination inhibiting (HAI) antibodies and rubella specific IgM antibodies by mu-capture ELISA. Ten of the 17 women were diagnosed to have acute rubella infection as they showed the presence of rubella specific IgM antibodies. Nine of these gave history of fever and rash whereas one woman remained asymptomatic. These observations suggest an increase in the incidence of rubella infection in pregnant women from March to May 1988 in Delhi.

Acute Disease↗
PubMed1990

Isolation and characterization of non-muscle tropomyosin cDNAs of human and mouse origin.

Several cDNA clones of human and mouse non-muscle tropomyosin have been isolated. All the human clones possess a common 23 bp sequence immediate 5' of the initiation codon. However, in the further upstream regions, the nucleotide sequences diverge. Two of the mouse cDNA clones pPSI-8 and pPSI-14 have identical nucleotide sequence in the coding region sequenced. However, 5' of the initiation codon these clones have only 40 identical nucleotides and further upstream the nucleotide sequences diverge. Analysis of the genomic DNAs of mouse cells indicated the possibility of a common gene giving rise to both the tropomyosin cDNAs differing in their 5' ends.

Amino Acid Sequence↗
PubMed1989

Localization of the muscle, liver, and brain glycogen phosphorylase genes on linkage maps of mouse chromosomes 19, 12, and 2, respectively.

Mammalian glycogen phosphorylases comprise a family of three isozymes, muscle, liver, and brain, which are expressed selectively and to varying extents in a wide variety of cell types. To better understand the regulation of phosphorylase gene expression, we isolated partial cDNAs for all three isozymes from the rat and used these to map the corresponding genes in the mouse. Chromosome mapping was accomplished by comparing the segregation of phosphorylase restriction fragment length polymorphisms (RFLPs) with 16 reference loci in a multipoint interspecies backcross between Mus musculus domesticus and Mus spretus. The genes encoding muscle, liver, and brain phosphorylases (Pygm, Pygl, and Pygb) are assigned to mouse chromosomes 19, 12, and 2, respectively. Their location on separate chromosomes indicates that distinct cis-acting elements govern the differential expression of phosphorylase isozymes in various tissues. Our findings significantly extend the genetic maps of mouse chromosomes 2, 12, and 19 and can be used to define the location of phosphorylase genes in man more precisely. Finally, this analysis suggests that the previously mapped "muscle-deficient" mutation in mouse, mdf, is closely linked to the muscle phosphorylase gene. However, muscle phosphorylase gene structure and expression appear to be unaltered in mdf/mdf mice, indicating that this mutation is not an animal model for the human genetic disorder McArdle's disease.

Amino Acid Sequence↗
PubMed1989

Subcellular composition of platelet density subpopulations prepared using continuous Percoll gradients.

Normal human platelets have been separated by density on continuous Percoll gradients and the subcellular composition of platelets of different density has been analysed. The number and concentration of dense granules increased significantly with platelet density, as did the concentrations of the dense granule constituents calcium and serotonin. The amount of serotonin per granule in the low density (LD) platelets was only two-thirds of the corresponding amount in the high density (HD) platelets. Platelets of all densities were able to sequester exogenous serotonin and release it in response to thrombin stimulation with similar efficiencies. The concentrations of the alpha-granule constituents von Willebrand factor and beta-thromboglobulin increased significantly with platelet density but the concentrations of the lysosomal enzyme beta-N-acetylglucosaminidase and total sialic acid did not differ significantly in the density subpopulations. The concentrations of the cytosolic enzymes lactate dehydrogenase and glucose-6-phosphate dehydrogenase were slightly higher in the LD population than in the other density subpopulations. The concentration of glycogen showed a marked positive relationship with platelet density and calculations suggested that glycogen was an important determinant of platelet density heterogeneity. The findings of the present study are compatible with recent suggestions that LD platelets may be slightly younger than HD platelets in normal human subjects.

Adult↗
PubMed1989

Study of an outbreak of epidemic conjunctivitis in Delhi in 1986.

An epidemic of acute conjunctivitis occurred in Delhi during July-September 1986. The clinical presentation in total of 350 patients were characteristic of acute haemorrhagic conjunctivitis (AHC). Bacterial cultures from conjunctival swabs were sterile in 85 out of 105 (80%) patients, virus cultures in Vero and HeLa cells were negative in 30 patients. However, conjunctival scrapes from 20/30 (66.7%) patients showed specific cytoplasmic fluorescence with enterovirus 70 (EV 70) antiserum, suggesting EV 70 to be the etiologic agent of the epidemic.

Adolescent↗
PubMed1988

Correlation of histologic types of carcinoma of the uterine cervix and human papillomavirus and herpes simplex virus type 2 DNA sequences in the uterine cervical biopsies.

Forty patients with invasive cancer of cervix from New Delhi were examined for the presence of human papillomavirus (HPV) and herpes simplex virus (HSV) type 2 DNA sequences in a Southern hybridization assay. Data were analysed according to the histologic type of cancer. HPV DNA sequences were detected in 82.5% biopsies and HSV-2 DNA sequences were found in 10% biopsies. HPV-16 DNA sequences were found either alone or together with HPV-18 and/or HSV-2 Bgl II N fragment in 55% biopsies from keratinizing squamous cell carcinoma, whereas HPV-18 sequences were found in 35% biopsies. Similarly, 50% biopsies from patients with non keratinizing squamous cell carcinoma contained HPV-16 DNA and 38.9% biopsies had HPV-18 DNA. HSV-2 Bgl II N DNA sequences were present in 10% biopsies which were also positive for HPV-16 and/or HPV-18 DNA sequences. Two biopsies from adenocarcinoma of uterine cervix contained HPV-18 and HPV-16 DNA sequences. Therefore, no significant correlation seems to exist between HPV-types and histologic types or grades of differentiation of tumor.

Adenocarcinoma↗