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Biomedical subjects

V Singh

Publications and source records attributed to V Singh.

At least 19 recordsLinked to original sources
PubMed2000

Disulfide bond formation is not required for human chorionic gonadotropin subunit association. Studies with dithiothreitol in JEG-3 cells.

To study the influence of disulfide bridge formation on the assembly of the subunits of human chorionic gonadotropin in JEG-3 choriocarcinoma cells, dithiothreitol (DTT) was used to create a reducing milieu in the endoplasmic reticulum (ER) in vivo. In the presence of 5 mM DTT during pulse-chase experiments all of the beta-subunit precursors observed in unperturbed cells (pbeta(0), pbeta(1), pbeta(2), and beta(*)) collapsed into the pbeta(0) form. The reducing milieu of the ER was reoxidized in less than 5 min after removal of DTT from the medium. DTT markedly increased the half-life of the pbeta(0) precursor from 8.8 to 65.2 min. Under reoxidation conditions, the beta-subunit precursors folded back from pbeta(0) in less than 5 min. In unperturbed JEG-3 cells, the alpha-subunit was present in both fully glycosylated and monoglycosylated precursor (pre-alpha) forms. The attachment of the second N-linked glycan residue of the alpha-subunit was accelerated in the presence of DTT, and consequently pre-alpha-subunit was missing from the DTT-treated cultures. The formation of alphabeta-dimers appeared to be at least partially independent of the oxidation state in the ER. The alphabeta-dimer was present under conditions in which disulfide bridge formation was prevented by exposure to 5 mM DTT before and during the pulse period. This clearly suggests that the human chorionic gonadotropin subunits may acquire association-competent conformations even when no disulfide bridge formation has taken place.

Chorionic Gonadotropin, beta Subunit, Human↗
PubMed2000

Determination of iodide by derivatization to 4-iodo-N,N-dimethylaniline and gas chromatography-mass spectrometry.

A real-time determination of iodide is proposed which involves the oxidation of iodide with 2-iodosobenzoate in the presence of N,N-dimethylaniline. The reaction is completed within 1 min to yield 4-iodo-N,N-dimethylaniline, which is extracted in cyclohexane and determined by GC-MS. It was also possible to determine iodine by derivatization in the absence of 2-iodosobenzoate, and iodate by its reduction with ascorbic acid to iodide and subsequent derivatization. A rectilinear calibration graph was obtained for 0.02-50 micrograms l-1 iodide with a correlation coefficient of 0.9998. The limit of detection was 8 ng l-1 iodide. The method was applied to the determination of iodate in iodized table salt and free iodide and total iodine in sea-water, and to spiked samples when the recovery was in the range 96.8-104.3% (RSD 1.9-3.6%). A sample clean-up by solid-phase extraction with a LiChrolut EN cartridge is proposed.

Gas Chromatography-Mass Spectrometry↗
PubMed2000

Budd-Chiari syndrome: our experience of 71 patients.

BACKGROUND: Hepatic venous outflow obstruction (Budd-Chiari syndrome) is frequently encountered as a cause of portal hypertension at our centre. METHODS AND RESULTS: We studied the clinical presentation, therapeutic modalities and outcome of 71 patients with hepatic venous outflow obstruction between 1992 and 1997. Twenty-seven patients presented with acute disease, while 44 had chronic presentation. Abdominal pain, distension, jaundice and upper gastrointestinal bleeding were the commonest presenting symptoms. The majority of patients had distended veins, hepatomegaly, splenomegaly, ascites and ankle oedema. The diagnosis was made on the basis of inferior vena cavography/functional hepatography and pulsed Doppler ultrasonography and/or liver biopsy in 39 patients and pulsed Doppler ultrasonography and/or liver biopsy in 32 patients. Pulsed Doppler ultrasonography accurately detected the site of the block in 31 of 39 patients (79.4%). The obstruction was in the hepatic vein in 20 patients, in the inferior vena cava in 10, and in both in 41 patients. Aetiologically, four had pregnancy-related disease, four tumour-related, three hypercoagulable states, 18 inferior vena cava membranes and 42 were idiopathic. Of 30 patients in whom liver biopsy was carried out, eight had centrizonal congestion and necrosis, 13 had mixed features and nine had established cirrhosis. Seven patients underwent a shunt operation and surgical membranotomy was carried out in one. Three patients (4.2%) died in the hospital. CONCLUSIONS: Hepatic venous outflow obstruction is a common problem; patients present with abdominal pain, distension, jaundice, distended veins, ascites and ankle oedema. Chronic presentation is more frequent. Pulsed Doppler ultrasound, venography and liver biopsy are very helpful in diagnosis.

Adolescent↗
PubMed2000

Superoxide anion formation and glutathione levels in patients with preeclampsia.

Increased free radical activity has been implicated in the pathogenesis of preeclampsia. This article investigates the glutathione status in preeclampsia and whether superoxide generation is enhanced in preeclampsia. Venous blood samples were obtained from 30 preeclamptic women and 30 normotensive pregnant women (controls). Superoxide generation and glutathione content were measured. There was a significant increase in superoxide generation and a marked reduction in glutathione content in preeclamptic women as compared to controls (p < 0.001). These results indicate that enhanced superoxide generation and impaired glutathione metabolism may be involved in the pathogenesis of preeclampsia.

Adolescent↗
PubMed2000

Study of the prevalence of asthma in adults in North India using a standardized field questionnaire.

Prevalence of asthma was calculated using a Hindi adaptation of the International Union Against Tuberculosis and Lung Disease (IUATLD)-1984 questionnaire. The questionnaire was administered to patients with and without asthma to select specific items to define asthma. Questionnaire validity was tested against physician-diagnosed asthma in 753 individuals in the field, with sensitivity and specificity of 63.1% and 98.8%, respectively. The field prevalence study was conducted among 958 men and 1158 women. True population prevalence, calculated from the observed prevalence using specificity and sensitivity of the questionnaire, was 3.94% in urban men, 3.99% in rural men, and 1.27% in both urban and rural women.

Adolescent↗
PubMed1999

The prolactin response to fenfluramine in schizophrenia is associated with negative symptoms.

We examined the serotonergic system in drug-free inpatients [schizophrenia (n=28) and schizoaffective (n=7)] by administering a challenge dose of oral dl-fenfluramine (fenfluramine) in a controlled angiocatheter study. Seventeen of these patients were also randomized to a placebo condition in addition to receiving fenfluramine. Response to fenfluramine as reflected by changes in serum prolactin and cortisol were examined by repeated measures ANOVA, as well as Area Under the Curves (AUCs). The prolactin response, but not the cortisol response, was significantly correlated with measures of negative symptoms.

Administration, Oral↗
PubMed1999

Biological behavior and etiology of inflammatory cervical smears.

Two hundred and fifty-seven consecutive women attending a major maternal and child health (MCH) center were studied clinically, colposcopically, cytologically, and microbiologically for different gynecologic infections. Out of 257 cases, 207 (80.5%) had inflammatory cervical smears, of which 183 (88.4%) were infected with one or more genital tract infections. Bacterial vaginosis (risk, 22.6-fold), chlamydia (risk, 21.6-fold), and human papillomavirus (HPV) (risk, 13.5-fold) were independently associated with inflammatory smears. In addition, significantly higher proportions of women with inflammatory smears had cervical ectopies (28.5% vs. 10.2%) and bleeding ectopies (30.9% vs. 4.1%) as compared to noninflammatory smears. Women infected with bacterial/parasitic genital infections were given specific treatment. These women were followed up at regular intervals to assess the efficacy of antimicrobial therapy. During follow-up examination, only 26 women (12.6%) showed negative smears. Sixteen women developed squamous intraepithelial lesions (SIL) during follow-up, and 163 women had persistent inflammatory smears. Multivariate analysis revealed that persistent inflammatory smears were associated with herpes simplex virus (HSV) infection, as revealed through detection of IgA antibodies to HSV (risk, 11.5-fold). Progression of SIL was associated with HPV infection (risk, 17.6 fold). Thus, inflammatory smears are associated with different types of infection, most of which do not respond to antimicrobial therapy.

Colposcopy↗
PubMed1999

Columnar and metaplastic cells in vault smears: cytologic and colposcopic study.

Vault smears (n = 250) were examined as routine follow up of hysterectomized individuals. Although the majority of these smears were normal, 14 of them revealed the presence of columnar cells or metaplastic cells. None of these patients had any known cause which could account for the presence of these cells in a post-hysterectomy smear. The possible explanations could be (i) the common mullerian origin of the upper vaginal mucosal cells, (ii) exfoliated reparative squamous parabasal and basal cells mimicking columnar cells, (iii) goblet cell metaplasia in atrophic vaginal epithelium.

Adult↗
PubMed1999

Serum levels of insulin-like growth factor binding protein-3 in benign and malignant breast disease.

BACKGROUND: The insulin-like growth factors IGF-I and IGF-II and their major binding protein IGFBP-3 influence the growth of breast cancer cells in vitro. Some benign non-breast tumours appear to be associated with increased serum IGFBP-3 levels which would tend to reduce bioactive-free IGF concentrations. The present study investigates whether this pattern also occurs in neoplastic breast disease. METHODS: Serum IGF-I, IGF-II and IGFBP-3 were measured by specific radioassay in 12 women with benign breast disease, 31 patients with breast cancer and in age-matched controls. RESULTS: The mean (+/-SD) serum IGFBP-3 concentration was higher in benign breast disease (3.6+/-0.7 mg/L) than in controls (2.7+/-0.6 mg/L) or in breast cancer patients (2.7+/-0.5 mg/L) (P = 0.001). Serum IGF-I and IGF-II levels were not significantly different among the groups. However, the index of free unbound IGF measured as the molar ratio of IGF-I plus IGF-II divided by IGFBP-3 was significantly lower in benign breast disease than in the other subjects. CONCLUSIONS: Either the production or clearance of IGFBP-3 is altered in benign breast disease so that there is less free IGF available to cells. This may serve to protect against malignant transformation in patients with benign breast disorders.

Adult↗
PubMed1999

Helicobacter pylori: evidence for spouse-to-spouse transmission.

BACKGROUND: Spouse-to-spouse transmission of Helicobacter pylori infection still remains controversial. METHODS: We studied the prevalence of H. pylori infection among spouses of H. pylori-positive or -negative individuals and looked for intraspousal transmission. Twenty-five couples were studied. Initially, one individual per couple was selected as the index subject. Spouses of these H. pylori-positive or -negative index individuals underwent screening for H. pylori by serology, the rapid urease test and histology. Those couples in whom only one spouse was positive were followed up and H. pylori status was re-evaluated using the above tests after approximately 1 year in the H. pylori-negative spouse. RESULTS: Of 25 randomly selected index subjects, 18 were H. pylori positive and seven were negative. There was no significant difference in age, sex, socioeconomic status, presence of dyspeptic symptoms, duration of marriage and number of children in these index subjects. Spouses of H. pylori-infected index subjects had a significantly higher prevalence of H. pylori infection than the spouses of H. pylori-negative index subjects (83.3 vs 28.5%; P < 0.01). Age, sex, socioeconomic status, dyspeptic symptoms, duration of marriage and number of children were not different in H. pylori-positive or -negative spouses of H. pylori-positive index subjects. There were five such couples in whom only one spouse was H. pylori positive initially. At follow up, three of these H. pylori-negative spouses became positive. These findings suggest person-to-person transmission or common source exposure within couples.

Adult↗
PubMed1999

Effect of rotavirus infection on small gut pathophysiology in a mouse model.

AIM: To study the effect of rotavirus infection on amino acid uptake in the small intestine in an experimental mouse model. METHODS: Infant mice (7-8 days of age) were orally infected with the EB serotype 3 strain of rotavirus and animals (both infected and control) were killed on days 0, 1, 3, 5, 7 and 10 post inoculation (PI) after recording their bodyweights. Gamma-glutamyltranspeptidase (GGT), leucine amino peptidase (LAP), glutathione (GSH) and leucine amino acid uptake in the jejunum and ileum were assessed. RESULTS: Infected animals showed significant reduction in their bodyweights and intestinal lengths on the third day PI compared with controls. Leucine amino peptidase, GGT, GSH and leucine uptake were significantly reduced in the ileum on the third and fifth day PI compared with controls while uptake in the jejunum was only reduced on third day PI. The LAP, GGTP, GSH and leucine uptake attained normal levels on the seventh day when diarrhoea stopped. Histology showed damage to the villi in the jejunum and prominent cytoplasmic vacuolation in the ileum of infected animals on the third and fifth day PI. CONCLUSION: Rotavirus affects amino acid uptake in the small intestine at the time of peak infection.

Animals↗
PubMed1999

Homeopathy in HIV infection: a trial report of double-blind placebo controlled study.

OBJECTIVE: This study was aimed to evaluate the immuno-modulator role of homeopathic remedies in Human Immunodeficiency Virus (HIV) infection. METHODOLOGY: A randomised double blind clinical trial was conducted to compare the effect of homeopathic remedies with placebo, on CD4+ve T-lymphocytes in HIV infected individuals, conforming to Centres for Disease Control (CDC) stage II & III. 100 HIV+ve individuals between 18-50 y (71% males) were included in the study. 50 cases conformed to CDC stage II--Asymptomatic HIV infection, and 50 cases to CDC stage III--Persistent Generalised Lymphadenopathy (PGL). Cases were stratified according to their clinical status and CD4+ve lymphocyte counts. The randomisation charts were prepared much before the start of the trial by randomly assigning placebo and verum codes to registration numbers from 1 to 50. A single individualised homeopathic remedy was prescribed in each case and was followed up at intervals of 15 d to one month. A six months study was performed for each registered case. Assessment of progress was made by evaluation of CD+ve lymphocyte counts, which was the prospectively-defined main outcome measure of the study; the results were compared with the base line immune status. RESULTS: In PGL, a statistically significant difference was observed in CD+ve T-lymphocyte counts between pre and post trial levels in verum group (P < 0.01). In the placebo group a similar comparison yielded non-significant results. (P = 0.91). Analysis of change in the pre and post trial counts of CD4+ve cells between groups was also statistically significant (P = 0.04). In asymptomatic HIV infection, differences in absolute CD4+ve lymphocyte counts between pre and post trial levels were not significant. Analysis of changes in pre and post trial CD4 levels of placebo and verum groups for combined strata of asymptomatic and PGL groups was also not significant. CONCLUSION: The study suggests a possible role of homeopathic treatment in HIV infection in symptomatic phase, as evidenced by a statistically significant elevation of base line immune status in persistent generalised lymphadenopathy.

Adolescent↗
PubMed1999

DDT and HCH residues in dairy milk samples collected from different geographical regions of India: a multicentre study.

Under a multicentre study conducted by the Indian Council of Medical Research, 2205 samples of dairy milk were collected from rural and urban areas of 12 states representing different geographical regions of India. These samples were analysed for residues of DDT and different isomers of HCH by gas-liquid chromatography. Analytical quality assurance between various participating laboratories was ensured through analysis of check samples. The residues of DDT and HCH were detected in more than 80% of samples analysed. Concentrations of DDT residues, alpha-HCH, beta-HCH, gamma-HCH and delta-HCH exceeded their maximum residue limits prescribed by the Ministry of Health and Family Welfare of the Indian Government in 37, 21, 42, 28 and 4% of the samples, respectively. Median values of DDT and HCH found in dairy milk in India were more than the corresponding values reported from most other countries. The results showed significant variations in the incidence as well as level of these contaminants in dairy milk from different regions of the country.

Animals↗
PubMed1999

Protective efficacy of trypsin inhibitor on the the gut following rotavirus infection in malnourished infant mice.

Epidemiologic data suggest a close relationship between protein energy malnutrition (or protein energy malnourished) (PEM) and development of infectious diarrheal diseases. In the present studies, the impact of trypsin inhibitor (TI) on the gut following rotavirus (RV) infection was investigated in PEM young growing inbred balb/c mice. The animals were divided into four groups: (1) control; (2) PEM; (3) PEM+RV and (4) PEM+ RV+TI. Control and PEM animals were orally inoculated with normal saline, PEM+RV animals were given 50 microl RV (100ID50) and PEM+RV+TI animals were inoculated with 0.6 mg TI/g body weight + 50 micronl RV. The body weight of each animal was recorded. Six animals from each group were sacrificed on days 0, 1, 3, 5, 7 and 10 post inoculation by cervical dislocation. The intestines were removed, everted and homogenized in ice-cold saline. Leucine aminopeptidase (LAP), glutathione (GSH) levels and L-leucine uptake were determined in the jejunum and ileum. Body weight was decreased in PEM and PEM+RV groups compared to the controls. LAP and leucine uptake levels were elevated in the PEM group but decreased in the PEM+RV group. GSH levels were decreased in the PEM+RV group. Enzyme activity, GSH and LAP uptake levels were restored in the PEM+RV+TI group. The study shows the protective role of soybean TI against RV infection in malnourished mice.

Animals↗
PubMed1999

How to use calcium antagonists in hypertension: putting the JNC-VI guidelines into practice. Joint National Committee for the Prevention, Detection, Evaluation and Treatment of High Blood Pressure.

The prevention and treatment of hypertension remain as major challenges for clinicians all over the world. The recently published Sixth Report of the Joint National Committee for the Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC-VI) uses evidence-based medicine in providing guidelines to aid clinicians in the prevention, detection and treatment of high blood pressure, including pharmacological approaches. Calcium antagonists are used widely for the treatment of hypertension, and JNC-VI focuses on specific situations where calcium antagonists could be considered as preferred treatments. There are a large number of calcium antagonists available, with a variety of pharmacodynamic and pharmacokinetic actions. Several sustained-release formulations of these drugs are also available. In terms of blood pressure control, calcium antagonists are more effective as antihypertensive treatments than beta-blockers, ACE inhibitors and angiotensin II receptor blockers in Black patients. The dihydropyridine calcium antagonists have been shown to reduce morbidity and mortality in elderly patients with isolated systolic hypertension. The rate-lowering calcium antagonists can be used as alternatives to beta-blockers in patients with coronary artery disease and hypertension. Calcium antagonists can be used as alternatives to ACE inhibitors in patients with hypertension and concomitant diabetes mellitus and/or renal disease. Some dihydropyridine calcium antagonists may be useful as alternatives to ACE inhibitors in patients with hypertension and systolic heart failure. Calcium antagonists appear to be extremely useful in patients with cyclosporin-induced hypertension, and in patients with hypertension and concomitant Raynaud's phenomenon and/or migraine. The rate-lowering agents can be used in patients with atrial tachyarrhythmias and hypertension. Clinicians should be aware of drug-drug interactions involving calcium antagonists, especially after the recent problems with mibefradil. Although retrospective studies have caused controversy regarding the safety of calcium antagonists in patients with hypertension, recent prospective studies have revealed no major safety concerns with these drugs.

Age Factors↗
PubMed1999

Relationship of flow and cross-sectional area to frictional stress in airway models of asthma.

Frictional stress from air flowing through narrowed airways may damage the airway mucosa and thereby increase airway inflammation and airway obstruction. To investigate the levels of frictional stress that might occur in the airway, we measured the frictional stress in three physical airway models (model 1: normal state; models 2 and 3: narrowed states with cross-sectional area half and one-fourth of model 1, respectively) at tracheal expiratory flow rates of 1, 2, 3, 4, 5, 6, 7, and 8 L/sec. Frictional stress measured at stations in the trachea (A), two each in the left (B and C) and right (D and E) major bronchi, and one in the right secondary bronchus (F) indicated that at higher flow rates, high values of the frictional stress seen in model 3 (highest value being 139.2 N/m2 at 8 L/sec at station) could well damage the airway wall, especially during episodes of cough, and particularly when the mucosa is inflamed and friable as it is in asthmatic patients. Conversely, control of cough may have anti-inflammatory benefits in asthmatic patients.

Adult↗