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Biomedical subjects

A R Singh

Publications and source records attributed to A R Singh.

At least 19 recordsLinked to original sources
PubMed2004

[Increased sensitivity for detection of mutations in exon 15 of the APC gene in patients with familial adenomatous polyposis].

BACKGROUND: Protein Truncation Test (PTT) was used to detect mutations in exon 15 of the APC gene in patients with Familial Adenomatous Polyposis. This method is limited by its ability to detect polypetide chains up to a certain minimum length. The aim of this study was to increase the sensitivity of detection of mutations in this region by using the technique of Denaturing Gradient Gel Electrophoresis (DGGE). METHODS AND RESULTS: Study were performed on 122 patients without detected mutations in the APC gene. The patients were divided into two independent groups 15A and 15A+15B (with 51 and 71 patients respectively). All the patients were tested with the DGGE and the positive findings were confirmed with sequencing. No mutation was detected in the group 15A (0%). In group 15A+15B one (1.4%) polymorphism and four (5.63%) patients with nonsense mutations were detected. CONCLUSIONS: DGGE is an effective method for detecting mutations in the first part of exon 15 of APC gene. It allows detecting any change in DNA strand. DGGE complements PTT in scanning of the whole exon 15 of APC gene.

Adenomatous Polyposis Coli↗
PubMed2001

Effect of mutations in Gag on assembly of immature human immunodeficiency virus type 1 capsids in a cell-free system.

Studies of HIV-1 capsid formation in a cell-free system revealed that capsid assembly occurs via an ordered series of assembly intermediates and requires host machinery. Here we use this system to examine 12 mutations in HIV-1 Gag that others studied previously in intact cells. With respect to capsid formation, these mutations generally produced the same phenotype in the cell-free system as in cells, indicating the cell-free system's high degree of fidelity. Analysis of assembly intermediates reveals that a mutation in the distal region of CA (322 LDeltaS) and truncations proximal to the second cys-his box in NC block multimerization of Gag at early stages in the cell-free capsid assembly pathway. In contrast, mutations in the region of amino acids 56-68 (located in the proximal portion of MA) inhibit assembly at a later point in the pathway. Other mutations, including truncations distal to the first cys-his box in NC and mutations in the distal half of MA (88HDeltaG, 85YDeltaG, Delta104-115, and Delta115-129), do not affect formation of immature capsids in the cell-free system. These data provide new information on the role of different domains in Gag during the early events of capsid assembly.

Amino Acid Sequence↗
PubMed2000

A trial of thyroxine in acute renal failure.

UNLABELLED: A trial of thyroxine in acute renal failure. BACKGROUND: Acute renal failure (ARF) remains a serious medical problem with a high mortality rate. Efforts to shorten the course of ARF might reduce this mortality. Since thyroxine has been shown in experimental models to shorten the course of ARF, we designed a trial to determine if a defined course of thyroxine would alter the course or change the mortality of clinical ARF. METHODS: A prospective, randomized, placebo-controlled, double-blind trial of thyroxine was carried out in patients with ARF. End points were the percentage requiring dialysis, the percentage recovering renal function, time to recovery, and mortality. RESULTS: Fifty-nine patients were randomized to receive either thyroxine or placebo. The groups were well matched in terms of basal and entry creatinines, age, sex, APACHE II scores at entry, and percentage oliguric. Baseline thyroid functions, including T3, T4, rT3, and thyroid stimulating hormone (TSH) levels, were equal between the two groups and typical of patients with euthyroid sick syndrome. Thyroxine resulted in a progressive and sustained suppression of TSH levels in the treated group, but had no effect on any measure of ARF severity. Mortality was higher in the thyroxine group than the control group (43 vs. 13%) and correlated with suppression of TSH. CONCLUSIONS: In contrast to the beneficial effects seen in experimental ARF, thyroxine has no effect on the course of clinical ARF and could have a negative effect on outcome through prolonged suppression of TSH. Critically ill euthyroid sick patients should not be replaced with thyroid hormone.

APACHE↗
PubMed1996

Superior sagittal sinus thrombosis in a child with nephrotic syndrome.

A 3-year-old male with steroid-responsive nephrotic syndrome developed a rare complication, sagittal sinus thrombosis during an episode of gastroenteritis, while on steroid therapy. Anticoagulation, as assessed by partial thromboplastin time, was difficult to maintain, despite administering high doses of heparin, infusions of fresh-frozen plasma to provide antithrombin III, and, subsequently, maximum doses of warfarin (0.3 mg/kg per day). Despite these problems the child made a complete neurological recovery.

Anti-Inflammatory Agents↗
PubMed1994

Psychiatric knowledge & orientation of non-psychiatrist doctors.

52 Non-psychiatrist doctors were evaluated in order to know their psychiatric orientation with the help of clinical case history along with questionnaire. Only one doctor subject could give all the diagnosis correctly on the basis of clinical stories; on the other hand all the doctors gave the diagnosis of epilepsy correctly. This reflects basic lack of understanding of psychiatry resulting from poor theoretical teaching and exposure at undergraduate level. Other characteristics of the sample and finding are discussed here.

Adult↗
PubMed1994

Socio-demographic pattern of drug and alcohol dependents.

The widespread abuse of drugs and Alcohol has become a human tragedy. Each year the abuse of Alcohol and Illicit drugs exact an enormous toll in deaths, decline in productivity, more crime and accidents and also increased expenditure in rehabilitation. The situation is likely to worsen and even may get out of hand if adequate measure are not taken to clearly identify the vulnerable group so as to provide them proper and maximal help. The present paper proposes to examine the sociodemographic correlates viz. Age, Sex group. Educational Status, Income Group, Marital Status and also possible causes of drug abuse of these patients. For this purpose patients of Dr. Vidya Sagar Hospital's drug-de-addition cum rehabilitation unit were statistically analysed. The findings have been discussed.

Adolescent↗
PubMed1976

Carcinogenic activity of a chlorinated polyether polyurethan.

On the basis of the results of an earlier study, a particular polyurethan sample (Y-238) was selected for further evaluation of its carcinogenic potential. This sample was subjected to physical and chemical tests for elucidation of its chemical structure, molecular weight, and molecular weight distribution. Additional biological tests were conducted on male NBR rats by implanting various quantities of the sample i.p., while others received an intrabronchus implant. Tumors, assessed histologically as malignant, were observed following both routes of implantation. The most common neoplasms of the pulmonary site was epidermoid carcinoma, while fibrosarcoma was the most common neoplasm in the peritoneal cavity. Data from the i.p. implantation suggested a dose-related incidence of cancers.

Animals↗
PubMed1975

Maternal-fetal transfer of 14C-di-2-ethylhexyl phthalate and 14C-diethyl phthalate in rats.

14C-Di-2-ethylhexyl and 14C-diethyl phthalates were administered intraperitoneally to pregnant rats on either Day 5 or 10 of gestation. Rats were sacrificed at 24-hr intervals starting on Days 8 and 11, respectively; maternal blood, fetal tissue, amniotic fluid, and placentas (whenever possible) were obtained. The 14C-activity of each sample was determined by scintillation counting. It was found that both diesters and/or their metabolic products were present in each of these compartments throughout the gestation period, thus suggesting that the embryo-fetal toxicity and teratogenesis reported previously could be the results of a direct effect of the compound (or its metabolites) upon developing embryonic tissue. Additionally, the reduction in concentration of 14C from these tissues as a function of time was found to fit a first-order excretion curve. From this model curve, the half-life for both compounds was calculated; the average was about 2.33 days for di-2-ethylhexyl phthalate and 2.22 days for diethyl phthalate.

Amniotic Fluid↗
PubMed1975

Carcinogenesis from polyurethans.

Seventeen polyurethans, containing various substituent groups, and a polyethylene were implanted i.p. in groups of male black Bethesda rats and were evaluated for carcinogenesis over a 2-year period. Thirteen of the polyurethans and the polyethylene were similarly studied in females. Tumor development in these animals was expressed in terms of the incidence in the at-risk population, and the tumorigenic latent period was approximated for each sample. Twenty months after implantation, the relative tumorigenicity (area under the corrected cumulative tumor mortality versus time curve) in the males ranged from 0 (for the unimplanted controls) to 6.18 (for Y-238); for female rats this range was 0.29 (for unimplanted controls) to 5.72 (for Y-238). Estimated latent periods in the males ranged from 5 months (for Y-304) to 16 months (for Y-303), and 22.5 months for the unimplanted controls; for the females, the range was from 9 months (for Y-290) to 13.5 months (for Y-217), and 14 months for the unimplanted controls. The relative tumorigenicity of each sample was also compared to its in vitro activation energy for thermal decomposition. These data are discussed in terms of solid-state versus chemical carcinogenesis.

Animals↗