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Biomedical subjects

T Singh

Publications and source records attributed to T Singh.

At least 19 recordsLinked to original sources

Trends in survival for children reported with maternally transmitted acquired immunodeficiency syndrome in New York City, 1982 to 1989.

To better understand the natural history of severe pediatric human immunodeficiency virus infection, reported cases of perinatally acquired pediatric acquired immunodeficiency syndrome (AIDS) in New York City were examined for differences in survival and age at diagnosis before and after implementation of an expanded case definition in 1987. One hundred ninety-six children reported through August, 1987, and 333 children reported between September, 1987, and February, 1990, and diagnosed through 1989 were compared. Significant differences were not found in survival by either gender or race/ethnicity although Hispanics were slightly more likely to be diagnosed with Pneumocystis carinii pneumonia (PCP) and blacks with lymphocytic interstitial pneumonitis (LIP). The most striking differences were noted regardless of race between children whose earliest AIDS-specific diagnosis was PCP and those whose earliest diagnosis was LIP. In the group reported through August, 1987, median survival from birth was 10 months with PCP vs. 54 months with LIP, median age at diagnosis 5 months vs. 20 months, and median survival after diagnosis 2 months vs. 22 months, respectively. Twelve-month survival for PCP improved in the two time periods examined, but survival with LIP did not. After implementation of the 1987 case definition, bacterial infections replaced LIP as the second most common diagnosis. This study provides data on children diagnosed and reported with AIDS. Ongoing prospective studies of children who have a full spectrum of human immunodeficiency virus infection with and without reportable AIDS wil further elucidate survival in children infected with human immunodeficiency virus.

Acquired Immunodeficiency Syndrome

Cardiovascular effects of omega-conopeptides in conscious rats: mechanisms of action.

We examined the effects of omega-conopeptides, a novel class of neuronal voltage-gated calcium channel antagonists, on hemodynamic responses in rats. Intravenous (i.v.) injections of SNX-111 (omega-conopeptide MVIIA) dose-dependently decreased arterial blood pressure (BP) in conscious rats. Intracerebroventricular (i.c.v.) SNX-111 injections (580 pmol) tended to increase BP and, after an initial decrease, to increase heart rate (HR). The dose-response curve for SNX-111 administered i.v. in conscious rats was biphasic. Beginning at subdepressor doses, SNX-111 caused a long-lasting blockade of pressor responses elicited by sympathetic nerve stimulation in pithed animals but did not prevent increases in BP evoked by exogenously administered norepinephrine (NE). Pretreatment of rats with histamine antagonists partially blocked the hypotensive effects of the higher (870 and 2,900 nmol/kg) doses of SNX-111. Substitution of alanine for arginine at position 10 ([Ala10]-MVIIA) markedly attenuated the histamine-mediated component of the vasodepressor response. Together, these findings indicate that SNX-111 administered i.v. decreases systemic BP by a combination of blockade of sympathetic neurotransmission and mast cell degranulation; the latter function appears to be dependent on the arginine residue in position 10 of the amino acid sequence of SNX-111.

Amino Acid Sequence

The effect of sulphonylurea therapy on serum total cholesterol and high density lipoprotein cholesterol.

A study was conducted on 50 cases comprising 25 patients of non-insulin dependent diabetes mellitus and 25 age and sex matched normal individuals. The diabetic state of the patients was controlled by glibenclamide, a sulphonylurea. The levels of serum total cholesterol and high density lipoprotein cholesterol were measured at the start and 15 and 30 days after glibenclamide therapy. There was a significant (p < 0.001) decrease in the levels of serum total cholesterol from initial 222.96 +/- 31.04 mg% to 218 +/- 28.99 mg% after 15 days and to 211.8 +/- 28.42 mg% after 30 days of therapy. In no case there was increase in serum total cholesterol level. There was a significant (p < 0.001) increase in the levels of serum high density lipoprotein cholesterol from initial 20.96 +/- 4.59 mg% to 21.8 +/- 4.78 mg% after 15 days to 23.72 +/- 5.07 mg% after 30 days of glibenclamide therapy and no case showed a fall in serum high density lipoprotein cholesterol level. This favourable alteration in serum total cholesterol and high density lipoprotein cholesterol was observed in patients of non-insulin dependent diabetes mellitus having ischaemic heart disease as well.

Adult

Survival in a cohort of human immunodeficiency virus-infected tuberculosis patients in New York City. Implications for the expansion of the AIDS case definition.

BACKGROUND: The occurrence of pulmonary tuberculosis in human immunodeficiency virus (HIV)-infected persons is believed to represent a less severe stage of HIV-related disease with a more favorable prognosis than other acquired immunodeficiency syndrome (AIDS)-defining conditions; therefore, it has been excluded from the AIDS definition established by the Centers for Disease Control (Atlanta, Ga) criteria. METHODS: To determine the prognosis of patients with HIV-related tuberculosis, we assessed the clinical, immunologic, and HIV infection status of a cohort of male subjects aged 20 to 44 years who were hospitalized with tuberculosis but without AIDS in New York City hospitals from 1985 through 1986, and we determined their mortality through May 1991. RESULTS: The 58 patients who agreed to participate were largely (90%) nonwhite and had a high prevalence of pulmonary tuberculosis (90%) and HIV infection (53%). Patients who were HIV seropositive had significantly lower CD4 cell counts (median, 0.136 x 10(9)/L; range, 0.013 x 10(9) to 2.314 x 10(9)/L vs median, 0.765 x 10(9)/L; range, 0.284 x 10(9) to 2.333 x 10(9)/L), and, during the follow-up period, an 83% mortality rate that was 7.5 times higher than the 11% rate in seronegative subjects. Survival analyses revealed that for all HIV-seropositive subjects the probability of death at 30 months was 72% and the median survival was 21 months (95% confidence interval, 15.5 to 26.5 months), while for HIV-seropositive subjects with CD4 cell counts of 0.2 x 10(9)/L or less, the probability of death at 30 months was 92% and the median survival was 15.75 months (95% confidence interval, 14.0 to 17.6 months). CONCLUSION: The prognosis for patients with HIV-related pulmonary tuberculosis is poor, and those with CD4 cell counts of 0.2 x 10(9)/L or less have survival patterns similar to that of patients with AIDS. We believe that these data support the expansion of the AIDS case definition to include persons with both pulmonary tuberculosis and severe HIV-related immunosuppression.

AIDS-Related Opportunistic Infections

Immunotoxic responses of cypermethrin, a synthetic pyrethroid insecticide in rats.

The study was undertaken to evaluate immunotoxic effects of cypermethrin administered orally (in ground nut oil) to male albino rats at dose levels (mg/kg) of 0 (control), 5, 10, 20 and 40 once daily for 90 days. Cypermethrin administration produced a significant leucopenia at 40 mg/kg on day 90. A dose dependent decrease (P greater than 0.05) in delayed type hypersensitivity reaction was noticed on day 61 post treatment. Humoral response as evidenced by serum haemagglutinin and haemolysin titres did not show any definite pattern on day 90. However, a significant decrease in spleen weights and significant increase in adrenal weights was recorded in rats receiving the highest test level. Total body weights and liver weights did not show any significant change with any of the dose level studied. Results of the study reveal that low doses (5 and 10 mg/kg) did not have any adverse effect on the immuno-competence of rats.

Administration, Oral

Glucoregulatory hormones in man at high altitude.

Concentrations of glucose, lactic acid, free fatty acid (FFA), insulin, cortisol and growth hormone (GH) in the blood were monitored in 15 euglycaemic men (sojourners, SJ) at sea level (SL) and while at altitudes of 3500 m and 5080 m, in acclimatised low landers (ALL) and in high altitude natives (HAN). In SJ, blood glucose and insulin concentrations showed a significant increase on the 3rd and 7th day after arrival at high altitude (HA), thereafter returning to sea level values and remaining the same during the entire period of their stay at 3500 m. Subsequently, on arrival at higher altitude (5080 m) the glucose concentrations again showed an increase over the preceding values and returned to SL values on day 41 while at 5080 m. A significant increase in cortisol concentrations was seen on day 3 after arrival at HA and the increased levels were maintained until day 21 at 3500 m. The cortisol concentrations on day 30 after arrival at 5080 m came down to SL values and remained unchanged thereafter. No appreciable change in GH and FFA was seen during the sojourn at HA. On the other hand, blood lactic acid concentration decreased significantly. There was no difference between the fasting glucose concentrations in ALL at 3500 m and in HAN at 3500 m and 4200 m compared to values of SJ at SL, whereas ALL at 4200 m had higher glucose values. Concentrations of plasma insulin and GH in ALL and HAN were higher than the values of SJ at SL, whereas cortisol values did not show any difference. These observations indicated that at HA the glucose values were high for the insulin concentration observed and might have been due to increased secretion of GH by the pituitary gland.

Adaptation, Physiological

Diabetes mellitus--a newly described risk factor for infection from Salmonella enteritidis.

Infections due to Salmonella serotype enteritidis have increased markedly in the northeastern United States. Due to the potential severity of these infections, host risk factors for infection were determined in the largest nosocomial S. enteritidis outbreak to have occurred in the United States. In a case-control study, patients in a New York City hospital who developed infection after exposure to an S. enteritidis-contaminated meal were more likely to be medication-dependent diabetics than were those who did not develop infection (17/75 vs. 7/80, Mantel-Haenszel adjusted odds ratio = 3.1, 95% confidence interval = 1.1, 8.6). Proposed mechanisms for diabetes as a risk factor for infection include decreased gastric acidity in diabetic patients and an autonomic neuropathy of the small bowel that reduces intestinal motility and prolongs gastrointestinal transit time.

Aged

The association between congenital syphilis and cocaine/crack use in New York City: a case-control study.

From 1987 to 1989, an epidemic of congenital syphilis was observed in New York City. A case-control study was done to assess the association between various maternal risk factors and congenital syphilis. Independent of the effect of other factors, the odds of being exposed to cocaine were 3.9 times greater among cases than controls (95% confidence interval, 2.8-5.3). This study suggests that the epidemic of congenital syphilis may be related to the increase in cocaine/crack use among delivering mothers.

Alcohol Drinking

Hydatid disease.

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Child

Iron status in patients of rheumatoid arthritis with special reference to serum ferritin levels.

Thirty patients of rheumatoid arthritis comprising 16 classical and 14 definite cases based on the ARA criteria were evaluated in a prospective and controlled study for iron status with special reference to serum ferritin levels. Serum ferritin levels were estimated by RIA technique and marrow iron status was ascertained by semi-quantitative estimation after Pearl's staining of marrow aspirate (G 0-6). Marrow iron stores were found absent to decreased in 17 patients (56.7%), normal in 2 (6.7%) and increased in 11 patients (36.6%). The serum ferritin levels in the iron depleted rheumatoid arthritis patients were significantly lower in comparison to patients with normal to increased marrow iron stores (23.91 +/- 11.45 ug/L vs 69.94 +/- 24.7 ug/L, p less than 0.001). There was a strong positive correlation between serum ferritin levels and marrow iron stores (r = +0.08, p less than 0.001). A serum ferritin value of less than or equal to 32 ug/L was a good predictor of decreased iron stores in the bone marrow, with a sensitivity of 88.2% and specificity of 84.5%. The test had a predictive value of 83.33%. There was no correlation between marrow iron stores and conventional indicators or iron status i.e. serum iron, TIBC, transferrin saturation and MCHC. It is concluded that serum ferritin correlates well with marrow iron stores and can be used as a simple non-invasive test for predicting iron-deficiency in patients of rheumatoid arthritis.

Adult

Contraceptive efficacy of Depot Provera jet-injected into the cervix.

Depot-medroxy progesterone acetate (DMPA) was jet deposited into the uterus/cervix of rats, rabbits and rhesus monkeys with the help of a modified jet injection apparatus. Since the drug was delivered under pressure, it was distributed deep into the muscular layers around the place of deposition. After one deposition the drug acted as an effective contraceptive for a period of three months. The merits of this delivery technique are discussed.

Animals

Aetiology of bacterial diarrhoea in north Indian children with special reference to Campylobacter jejuni.

A total of 184 cases of acute diarrhoea, in patients aged 1-36 months, were studied clinicobacteriologically. Enteropathogens were isolated in 22.28% cases. Campylobacter jejuni was isolated from 2.17% cases only. Salmonellae were isolated from 7.6% cases and 64.28% of them were S typhimurium. More than 75% of all isolates of salmonellae, shigellae, Esch coli and Campylobacter jejuni were sensitive to gentamicin and cephaloridine. Secondary lactose intolerance was noted in 6.52% cases only.

Campylobacter

Pure red cell aplasia.

Eleven cases of Pure red cell aplasia (PRCA) in children were encountered in our hospital since 1982. The age range was 4 months to 12 years. There was a male preponderance with M:F ratio as 9:2. There were 4 cases due to viral fever, 1 with bronchopneumonia, 2 of tuberculosis, 1 of enteric, 1 of NHL and 2 were of congenital PRCA. Tuberculosis per-se had given rise to PRCA in the two cases, which is not reported earlier though its association with anti-tubercular therapy is well recorded. Cases of infective etiology other than viral responded very well to specific treatment. Steroid was the drug of choice in PRCA with viral etiology.

Child