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Biomedical subjects

V Singh

Publications and source records attributed to V Singh.

At least 181 records · Page 10Linked to original sources
PubMed1996

Cellular immune response to retinal S-antigen & interphotoreceptor retinoid binding protein fragments in idiopathic human uveitis.

The role of retinal antigens in idiopathic human uveitis has been studied in 38 patients of uveitis, and 30 patients of systemic connective tissue disease (CTD) and 30 healthy volunteers. Lymphocyte proliferative responses were tested in vitro against native S-antigen, its uveitopathogenic peptides (peptide M, peptide G), yeast histone H3 peptide and uveitopathogenic fragment of interphotoreceptor retinoid binding protein (IRBP: R16) to establish their role in pathogenesis of human uveitis. Seven patients with uveitis, and none among CTD patients and healthy volunteers, responded (stimulation index > 3) to at least one retinal antigen used. One uveitis patient showed response to native S-antigen, peptide M and yeast histone H3. One responded to both S-antigen and peptide M and another responded to both peptide G and R16 peptide. Two responded to S-antigen only, one to peptide M and one to peptide G. In addition, one uveitis patient responded to yeast histone H3 only. These results suggest that retinal antigens may play a role in the etiopathogenesis of a subset of idiopathic human uveitis.

Adolescent↗
PubMed1996

Mutagenicity of endocervical mucus associated with genital tract infections.

Mutagenic metabolites produced due to chronic infection of cervical epithelium are suspected to be a plausible risk factor in cervical carcinogenesis. One hundred twenty-four symptomatic women attending a maternal and child health (MCH) clinic were studied clinically, cytologically, microbiologically, and biochemically for genital tract infections and for the presence of mutagens in the endocervical secretions using Ames' test. Human papillomavirus (HPV) was the leading infection (53.3%), followed by chlamydial infection (25.8%) and seropositivity for herpes simplex virus (25.1%). Mutagenic products in the endocervical secretions was detected in 23 women (18.5%). The univariate and multivariate (adjusted for other genital infections, age, and parity) analysis showed that the mutagenic mucus was associated with only chlamydial infection of endocervical region (OR = 3.7; 95% CI = 1.7,7.3). This shows that chlamydia is associated with mutagenicity of endocervical mucus.

Cervix Mucus↗
PubMed1996

Study of oxidative-stress in rotavirus infected infant mice.

Rotavirus induced diarrhoea was investigated in neonatal mice. Assessment of oxidative/antioxidative profile was the mechanistic approach to study the nature of injury. Neonatal mice (NMRI strain) were infected orally with the homologous strain of (EB) rotavirus (serotype 3). The peak severity of rotavirus infection was attained on the third day post infection. The whole small intestine of neonatal mice on day 3 post infection was homogenized and analysed for oxidative/antioxidative profile. Glutathione and related thiols were significantly declined in rotavirus infected group. Superoxide dismutase, glutathione peroxidase and glutathione-S-transferase (1-chloro 2, 4 dinitrobenzene) activities were also decreased in the rotavirus infected group. The activities of glutathione reductase and glutathione-S-transferase (ethacrynic acid) however were elevated with rotavirus infection in comparison to the control group. Similarly, ADP-FeCI3, NADPH induced lipid peroxidation was elevated with rotavirus infection. Thus the altered oxidative/antioxidative profile indicated the presence of oxidative stress in the rotavirus infected group and can be postulated to have a prominent role in the pathogenesis of the disease.

Animals↗
PubMed1996

Colposcopy as a tool for detection of human papillomavirus infection of uterine cervix in the setting of high prevalence of gynaecologic infections.

A cross sectional study involving 257 women from the Maternal and Child Health Centre (MCH) in Delhi was initiated for screening clinically, cytologically, colposcopically, and microbiologically for several gynaecologic infections. Eighty percent of the women had one or more gynaecologic infections and 31.1% had three or more infections. Cytology revealed changes suggestive of condyloma in 3 (1.2%) women only, while colposcopic examination suggested HPV changes in 117 (45.5%) women. A very high proportion of colposcopically detected lesions (78.6%) had evidence of HPV related changes in histology. The specificity of these lesions were further confirmed by Pan HPV DNA in-situ hybridisation, when 84% of the colposcopy is a valuable tool for detecting subclinical HPV lesions in a setting with high prevalence of gynaecologic infections.

Colposcopy↗
PubMed1996

Serial blood phosphine levels in acute aluminium phosphide poisoning.

Serial blood phosphine (PH3) levels were done in patients with severe (Group I, n = 30), mild (Group 2, n = 10) and minimal or nil toxicity due to aluminium phosphide compound. Blood phosphine levels were significantly higher (p < 0.001) in patients of Group I than other two groups. Phosphine was not detectable in Group 3 patients. Therefore, blood phosphine levels were positively correlated to clinical grades of toxicity and to dose of active pesticide consumed. Higher the blood phosphine, higher was the mortality. Patients having blood phosphine levels equal to or less than 1.067 +/- 0.16 mg% survived, hence, it appeared to be limit of phosphine toxicity.

Adult↗
PubMed1995

Loss of p75 nerve growth factor receptor mRNA containing neurons in rat forebrain after intraventricular IgG 192-saporin administration.

Cholinergic neurons of the basal forebrain express the p75 (low affinity) nerve growth factor receptor (NGFr) on the cell surface. It has been previously shown that an immunotoxin that recognizes the p75 NGFr, IgG 192-saporin, eliminates these neurons as judged by a variety of techniques after intraventricular injection into rat brain. Here we show that this loss of neurons can also be identified by detecting the disappearance of the p75 NGFr mRNA utilizing a non-radioactive in situ hybridization method.

Animals↗
PubMed1995

Release of iron from ferritin by 1,2,4-benzenetriol.

Release of iron from ferritin in the presence of polyhydroxy metabolites of benzene i.e., hydroquinone (HQ) or 1,2,4-benzenetriol (BT) was studied in acetate buffer, pH 5.6. The release of iron from ferritin was quantitated by monitoring the formation of iron-ferrozine complex. The presence of hydroquinone (330 microM) did not result in the release of iron from ferritin, whereas the same concentration of BT resulted in the release of significant amounts of iron (3.2 microM/min) from ferritin. BT concentration-dependent increase in iron release from ferritin was observed although the increase was not linear with the concentration of BT. Under a N2 atmosphere the presence of BT resulted in the release of iron (2.1 microM/min) from ferritin. The presence of oxyradical scavengers i.e., albumin, catalase or superoxide dismutase significantly inhibited iron release from ferritin by BT. The iron released from ferritin by BT enhanced lipid peroxidation in rat brain homogenate and released aldehydic products from bleomycin-dependent degradation of DNA. Addition of BT to bone marrow lysate resulted in an increase of iron release as a function of time. These studies indicate that BT is a potent reductant of ferric iron of ferritin and also mobilizes and releases iron from ferritin core. The release of iron from bone marrow lysate by BT may be of toxicological significance as this could lead to disruption of intracellular iron homeostasis in bone marrow cells.

Acetates↗
PubMed1995

Genetic alterations at 5p15: a potential marker for progression of precancerous lesions of the uterine cervix.

BACKGROUND: Development of uterine cervical cancer is preceded by preneoplastic proliferative changes in the cervical epithelium called "intra-epithelial neoplasia" or "dysplasia." The genetic basis of the origin and progression of such preneoplastic lesions is not known. By analysis of carcinomas for loss of constitutional heterozygosity (LOH), we have previously shown a high frequency of allelic loss in the short arm of chromosome 5 (5p), suggesting loss of a candidate tumor suppressor gene located in 5p and associated with the development of this tumor. PURPOSE: To further understand the role of genetic alterations that affect 5p in cervical carcinogenesis, we evaluated the status of microsatellite polymorphisms at five loci mapped to 5p14-ter in precancerous and cancerous lesions. METHODS: Biopsy specimens from two groups of patients were analyzed for genetic alterations affecting 5p. One group comprised 14 cases of precancerous lesions (i.e., dysplasias) and five cases of carcinoma in situ (CIS); the second group comprised 46 previously untreated patients with invasive carcinoma. Tumor and normal DNAs were analyzed by polymerase chain reaction for genetic losses and instability at five polymorphic microsatellite loci (D5S392, D5S406, D5S208, D5S117, and D5S432) mapped to 5p. RESULTS: LOH was observed in 25 (55.6%) of 45 informative invasive carcinomas, one (20%) of five cases of CIS, and three (21%) of 14 precancerous lesions. Among the loci tested, D5S406 (5p15.1-15.2) exhibited LOH in 12 (48%) of 25 invasive carcinomas, one (33%) of three cases of CIS, and three (60%) of five precancerous lesions, suggesting this to be the site in 5p of the novel candidate tumor suppressor gene. In addition, replication error-type alterations were noted in the 5p14-ter region in six (13%) of 46 invasive carcinomas, two (40%) of five cases of CIS, and three (21%) of 14 precancerous lesions. Instability affected D5S406 in eight (66.7%) of 12 instances that showed microsatellite instability. CONCLUSION: These observations suggest that allelic loss and microsatellite instability in the region of D5S406 may play a role early in the development of cervical carcinoma and identify the site of a candidate tumor suppressor gene. These genetic markers (allelic loss and microsatellite instability) may also define CIS and precancerous lesions at high risk for progression to invasive cancer. IMPLICATIONS: The future molecular cloning of the candidate tumor suppressor gene at 5p15.1-15.2 may provide new insights into the genetic mechanisms of cervical carcinogenesis. Analysis and clinical follow-up of a large cohort of prospectively ascertained cases of precancerous lesions would help to validate the usefulness of these markers.

Biomarkers, Tumor↗
PubMed1995

Clinical presentation of gynecologic infections among Indian women.

OBJECTIVE: To study the clinical presentation of different gynecologic infections among Indian women. METHODS: This was a cross-sectional study of 257 women that included clinical, cytologic, colposcopic, and microbiologic screening for various gynecologic infections. RESULTS: Human papillomavirus (HPV) was the leading infection, affecting 127 (49.4%) women; however, overt warts were only seen in seven (2.7%) patients. Women infected with HPV had a 60.3-fold higher risk of developing a bleeding ectopia compared to those with other infections; women with an unhealthy cervix and cervical ectopias also had an increased risk of HPV infection (7.6- and 2.8-fold, respectively). Bacterial vaginosis, detected in 33.5% of the women studied, had an increased risk of bleeding ectopia (9.3-fold), cervical ectopia (3.1-fold), cervicitis (2.9-fold), vaginitis (6.9-fold), and cervical hypertrophy (2.1-fold). Chlamydial infection, detected in 23.3% of the patient population, was associated with an eightfold increase in the risk of an unhealthy cervix and a fourfold increase in risk of a hypertrophied cervix. Immunoglobulin-A antibodies to the herpes simplex virus were detected in 53 (20.6%) women. More than half (55.2%) of the women had two or more infections, and the mean delay of seeking medical treatment was 7-13 months. CONCLUSION: The specific finding of bleeding cervices was associated with HPV and bacterial vaginosis, hypertrophied cervices with chlamydia and bacterial vaginosis, and unhealthy cervices with chlamydia and HPV infections.

Adult↗
PubMed1995

Serum 25-hydroxyvitamin D3 levels decreased in impaired glucose tolerance and diabetes mellitus.

A cross-sectional survey was carried out in a New Zealand Polynesian and Caucasian workforce of 5677 staff aged 40-64 years to determine whether serum concentrations of 25-hydroxyvitamin D3 are altered in people with newly diagnosed diabetes mellitus and impaired glucose tolerance (IGT). Serum 25-hydroxyvitamin D3 concentration was significantly lower in newly detected cases with diabetes and IGT (n = 238) compared with controls individually matched by sex, age (+/- 2 years), ethnicity, and date of interview (mean (S.D.): 69 (31) vs. 76 (34) nmol/l; P = 0.0016). Among controls, serum concentrations were significantly lower in Maori (mean (S.E.) = 65 (5) nmol/l; P = 0.0013) and Pacific Islanders (59 (4) nmol/l; P = 0.0001) compared with Europeans (82 (3) nmol/l), after adjusting for age, sex, and time of year. We conclude that diabetes and IGT are associated with low serum concentrations of 25-hydroxyvitamin D3 and that low concentrations of this hormone in New Zealand Polynesians may partly explain their increased prevalence of diabetes/IGT compared with Europeans.

Adult↗
PubMed1995

Studies on uptake of trivalent and hexavalent chromium by maize (Zea mays).

Pot culture experiments were carried out to study the uptake and translocation of chromium from irrigation water when supplied in its trivalent and hexavalent states to maize plants grown in soil and sand culture. The uptake of chromium was observed to increase with increase in the concentration for both oxidation states of chromium. For the root, the observed order of uptake was CrIII sand > CrVI sand > CrIII soil > CrVI soil, whereas in the lower shoot, upper shoot and fruit the order was CrVI sand > CrVI soil > CrIII sand > CrIII soil. Significantly high uptake of chromium by roots in the sand culture (CrIII treatment) is attributed to the effect of root exudates and degradation products on the mobilization of CrIII. In aerial parts of the plants a higher uptake was observed when the initial supply was CrVI. The trends observed are explained on the basis of the redox behaviour of chromium.

Chromium↗
PubMed1995

Plant uptake of fluoride in irrigation water by ladyfinger (Abelmorchus esculentus).

Because of suggestions that food is a rich source of fluoride to humans and the absence of permissible and upper limits of fluoride for irrigation water, plant uptake studies were conducted using fluoride-rich irrigation water. Ladyfinger was grown in sand and soil cultures for 18 wk and the accumulation of fluoride in various plant parts was studied. The potential for ingestion of fluoride by humans through this route was also considered. The percentage uptake was greater in sand-cultured plants than in soil-cultured plants. The root accumulates most of the fluoride supplied through irrigation water and the fruit accumulates the least. Up to 120 mg fluoride/litre of irrigation water did not harm the plants. The ingestion of fluoride by humans from plants irrigated with water containing 10 mg fluoride/litre would be 0.20 mg per 100 g ladyfinger.

Fluorides↗
PubMed1995

Polyclonal antibody-based antigen-detection immunoassay for diagnosis of Trypanosoma evansi in buffaloes and horses.

An enzyme-linked immunosorbent assay (ELISA) was employed for the detection of Trypanosoma evansi antigens in serum samples of field cases of buffaloes and horses in northern India. In 323 naturally infected/suspected buffaloes, circulating antigenaemia was detected in 180 (55.72%), whereas parasitaemia by wet blood smear examination was found in 62 (19.19%) only. The antigen-ELISA was positive in 47 of the 62 parasitologically proven cases and in 86 of the 116 cases with anti-trypanosome antibodies detected by ELISA. Of the 80 horses examined antigen-ELISA was positive in 45 (56.75%) sera. The antigen-detection assay was positive in 14 of the 19 parasitaemic cases whereas the antibody-detection assay was positive in 18 of the 30 parasitaemic cases. In the present study, antigen-ELISA was found to be more sensitive and specific compared with antibody-ELISA and wet blood examination, and could prove a useful tool for epidemiological studies of latent trypanosomosis in livestock.

Animals↗
PubMed1995

Polypeptide profiles and antigenic characterization of cell membrane and flagellar preparations of different stocks of Trypanosoma evansi.

Polypeptides and antigens of cell membrane (CM) and flagellar (Fl) preparations of seven different stocks of Trypanosoma evansi were studied using sodium dodecyl sulphate polyacrylamide gel electrophoresis and by Western blotting. The stocks were collected from Bareilly, Bikaner, Hisar Karnal, Lucknow and Ludhiana localities of northern India and were isolated from either buffalo, equids or camel. Between two and five polypeptides with molecular weights (MW) ranging from 48.4 to 80.2 kDa (except one stock) were detected in the CM preparations and between four and 12 polypeptides ranging from 17.6 to 80.2 kDa were observed in the Fl preparations. The 78.3 kDa polypeptide was common to the CM preparation of all seven stocks. The number of antigens found in the CM of different stocks using homologous and heterologous hyperimmune sera (HIS) varied between three and 11 and were in the MW range of 25-98 kDa. Likewise the number of Fl antigens of different stocks varied between three and 14, predominantly in the MW range 17-98 kDa. Antigenic cross-reactivity among polypeptides of the CM and Fl preparations detected by various HIS was also high, indicating the possibility of less antigenic variability among these seven stocks.

Animals↗
PubMed1995

Serum 25-hydroxycholecalciferol concentration in newly detected hypertension.

Although blood concentrations of the active metabolite 1,25-dihydroxyvitamin D are raised in hypertension, concentrations of 25-hydroxyvitamin D, the main vitamin D metabolite, do not appear to have been reported in newly detected hypertension. Serum levels of 25-hydroxycholecalciferol were measured in 186 newly detected hypertensive patients (blood pressure > 160/95 mm Hg and never on antihypertensive medication) and normotensive controls individually matched by sex, age (+/- 2 years), ethnicity, and date of interview. Serum 25-hydroxycholecalciferol levels were similar in cases (mean (SD) = 64 (21) nmol/L) and controls (67 (28) nmol/L, P = .20). We conclude that serum 25-hydroxycholecalciferol, a marker of body vitamin D, is normal in hypertension.

Age Factors↗
PubMed1995

Multidisciplinary management of dysphagia: the first 100 cases.

A report of the first 100 patients treated in the multidisciplinary Dysphagia Clinic in Salisbury District Hospital is presented. It was established in January 1992 and involves the Departments of ENT Surgery, Clinical Radiology and Speech and Language Therapy. In the first 18 months, 100 patients have been assessed and treated. These included 46 males and 54 females, between the ages of four and 93 years. Neurological problems accounted for 39 cases. The management comprised the assessment clinic, videofluoroscopy in 83 patients, and finally the appropriate treatment. Forty-four patients were treated primarily by swallowing therapy. Seventy-three patients showed complete recovery, resolution of their symptoms or did not require treatment. Two patients were still under treatment at the time of writing this paper.

Adolescent↗
PubMed1995

Induction of DNA single-strand breaks in human lymphocytes by low doses of gamma-rays.

We hypothesized that very low doses of gamma-rays have a genotoxic effect as measured by DNA single-strand breaks (ssbs). To test our hypothesis we used a newly developed alkaline microgel electrophoretic technique to quantitate DNA ssbs in freshly isolated human lymphocytes. An enhanced sensitivity to detect low levels of DNA damage was made possible by this method due to an additional step of DNA precipitation by ethanol in agarose microgels. We exposed lymphocytes from three subjects for 1 h at 4 degrees C to 740 MBq of technetium 99-m at a distance of 20 cm (0.25 mGy), 10 cm (1.02 mGy), and 5 cm (4.08 mGy) from the source vial. Doses of 1.02 and 4.08 mGy induced a significant dose-dependent increase in DNA ssbs in human lymphocytes from three subjects, each examined on three different days.

DNA Damage↗