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Biomedical subjects

S Nityanand

Publications and source records attributed to S Nityanand.

At least 37 records · Page 2Linked to original sources
PubMed1997

A bias in the alphabeta T cell receptor variable region gene usage in Takayasu's arteritis.

Takayasu's arteritis (TA) is a chronic large vessel vasculitis with a predilection for the aortic arch and its branches. T lymphocytes may be important in the pathogenesis, as they have been found to infiltrate the vascular lesions. To elucidate further the role of T cells in the disease, we studied circulating CD4+ and CD8+ T cells, expression of the activation marker (HLA-DR), marker for naive (CD45RA) and primed (CD45RO) cells and the different variable alpha/beta (AV/BV) gene segments on them. The TCR AV/BV repertoire was studied using a panel of 15 T cell receptor (TCR) V-specific MoAbs by flow cytometry in 18 patients and 23 age- and sex-matched controls. Patients had a higher percentage of AV12S1 (P < 0.05), BV6S7 (P < 0.05) and BV9 (P < 0.001)-bearing CD4+ cells. Patients also had a higher frequency of expansions, i.e. of T cell populations with an abnormally high TCR AV/BV gene usage. In patients' CD4+ subset of cells, there were 22 expansions out of 231 analyses (9.5%), whereas in controls, four were expanded out of 310 analyses (1%) (P < 0.001). For CD8+ cells, the frequency of expansions was 32 in 231 analyses (14%) in patients and nine out of 304 analyses in controls (3%) (P < 0.01). In addition, there was a correlation between CD4+ expansions and disease activity; nine out of 10 patients with active disease in comparison with two out of eight patients with inactive disease (P < 0.01) had an expansion. Some of the expanded populations in patients were phenotypically characterized and observed to be HLA-DR+, CD28+, CD45RA+ and CD45RO+, with a greater proportion being CD45RO+. Patients had a higher percentage of expression of HLA-DR on both CD4+ and CD8+ T cells (P < 0.01). The percentages of naive and primed CD4+ and CD8+ T cells, gammadelta+ T cells and natural killer cells were comparable to those in the control group.

Adult↗
PubMed1997

Antibodies against cardiolipin and oxidatively modified LDL in 50-year-old men predict myocardial infarction.

Autoantibodies against oxidatively modified low-density lipoproteins (oxLDL) and cardiolipin occur in patients with vascular diseases, including atherosclerosis. The ability of such antibodies to predict myocardial infarction (MI) was investigated in a prospective nested case-control study in which healthy 50-year-old men were followed up for 20 years. Raised levels of antibodies against oxLDL and cardiolipin at 50 years of age correlated positively with the incidence of MI and mortality related to MI 10 to 20 years later. IgG and IgA antibodies against cardiolipin were associated with MI between 50 to 60 years of age and IgG and IgA antibodies against oxLDL with MI at 60 to 70 years of age. Moreover, higher antibody levels were noted in those who died from acute MI in comparison to those who survived. The predictive power of IgA and IgG antibodies was strong and largely independent of that of other strong risk factors. In conclusion, raised levels of antibodies against oxLDL and cardiolipin may predict MI and MI-related death.

Aged↗
PubMed1995

Pharmacokinetics of centchroman in healthy female subjects after oral administration.

The pharmacokinetics of centchroman, a non-steroidal antifertility agent, were assessed in serum of eleven healthy female subjects after a single 30 mg oral dose. Maximum serum concentration (Cmax) of 55.53 (s.d., 15.45) microgram/L was attained at 5.18 (s.d., 1.78) h after oral administration. The concentration-time profile was best described by a two-compartment open model with bi-exponential disposition functions. The mean terminal elimination half-life (t1/2) was 165 (s.d., 49) h with a clearance of 6.17 (s.d., 1.67) L/h and volume of distribution of 1420 (s.d., 478) L. Comparison of the pharmacokinetic parameters of this study with those obtained after a single 60 mg oral dose did not show statistically significant differences in the rate of absorption, distribution and elimination. The Cmax and AUC0-infinity were dose-dependent. Thus, the absorption and disposition of centchroman are of first-order, reproducible and dose-dependent.

Administration, Oral↗
PubMed1995

Centchroman: a new non-steroidal oral contraceptive in human milk.

Centchroman, a non-steroidal oral contraceptive drug, was given to 13 nursing mothers comprising two groups. Each participant in group I (n = 8) received a single 30 mg dose, and in group II (n = 5) each participant received a 30 mg twice a week dose for twelve weeks. Simultaneous blood and milk samples were collected and analyzed for the parent drug by high performance liquid chromatography. In the single dose study (group I), the mean +/- peak centchroman concentrations in milk and serum were 78.7 +/- 28.4 and 63.6 +/- 23.6 ng/ml with milk-to-serum (M/S) ratio of 1.4 +/- 0.9. There was no significant increase in centchroman concentrations in milk after multiple dosing (group II). However, serum concentrations reached up to 112.5 ng/ml at 6 h after the 13th dose. Average M/S ratios were insignificantly different at trough (prior to next dose) and at peak (4-6 h after dose) centchroman levels. Additionally, the breast milk and serum centchroman concentrations showed a significant correlation (r = 0.64, P < 0.01), indicating that the amount of centchroman excreted into breast milk is dependent on serum concentrations. The weekly dose (% of the maternal dose) of centchroman ingested by the breast-fed infant at peak maternal serum and milk levels was in the range of 0.4 to 11.5%, assuming a weekly milk uptake of 1.05 l/kg. There was no significant difference in the dose ingested by the infants between the two dosing groups. These levels of centchroman passing into breast milk and subsequent exposure to the infants are unlikely to be of any physiological consequence.

Administration, Oral↗
PubMed1995

T cell receptor (TCR) V gene usage in patients with systemic necrotizing vasculitis.

Wegener's granulomatosis (WG) and polyarteritis nodosa (PAN) are systemic necrotizing vasculitides of unknown etiology. These disorders run a fatal course if untreated. T lymphocytes are implicated in the pathogenesis of WG, since they have been found to infiltrate affected organs, and sIL-2R correlates with disease activity. To elucidate further the role of T cells in necrotizing vasculitis, we have used a panel of 12 TCR V-specific MoAbs to investigate the number of cells expressing certain V alpha and V beta gene segments in the CD4+ and CD8+ subsets of altogether 11 patients with WG or PAN. In the group of patients, we found abnormal expansions of T cells using particular TCR V alpha or V beta gene products. These T cell expansions were more numerous, of a dramatically higher magnitude, and frequently more often found in the CD4 subset, compared with T cell expansions identified in healthy individuals. In long-term studies of the T cell expansions for up to 18 months, a heterogeneous pattern was revealed, with no obvious correlation to clinical features such as disease activity or treatment. Studies of TCR V gene usage in this group of patients may help in understanding the pathogenesis of necrotizing vasculitis, and in the identification of unknown antigens, and may open the possibility to a highly selective immunotherapy by targeting disease-mediating T cells.

Aged↗
PubMed1995

Antibodies against endothelial cells and cardiolipin in young patients with peripheral atherosclerotic disease.

OBJECTIVES: To investigate the prevalence of anticardiolipin and antiendothelial cell antibodies in patients operated on for atherosclerotic peripheral vascular disease before 50 years of age. The hypothesis to be tested was whether antibodies associated with an immune/inflammatory damage to the vascular wall were associated also with early atherosclerosis. DESIGN: A case-control study. SETTING: Departments of surgery and an immunological research laboratory, and routine laboratories of two tertiary referral hospitals. SUBJECTS: All patients operated for atherosclerotic peripheral vascular disease before 50 years of age. Sixty-two patients (33 males, 29 females), and 67 age- and sex-matched controls participated. The diagnosis of atherosclerosis was made on the basis of the clinical presentation and angiographic visualization of the diseased vasculature. MAIN OUTCOME MEASURES: Subjects were compared for the prevalence of anticardiolipin and antiendothelial cell antibodies, altered serum lipoprotein levels, smoking, diabetes, hypertension, and signs of inflammation. RESULTS: Antibodies against endothelial cells and cardiolipin were found in 12.9 and 14.5% of the patients, respectively, which was higher than observed in the control group (P < 0.05). Sixty per cent of patients with antibodies were females. Conventional risk factors were more often noted in the patient group. However, patients with antibodies against endothelial cell and/or cardiolipin had a lower prevalence of hyperlipidaemia/dyslipidaemia when compared to patients without these antibodies (P < 0.05). CONCLUSIONS: Antibodies against endothelial cells and cardiolipin are present in a subset of patients with clinical and angiographic diagnosis of severe premature atherosclerotic peripheral vascular disease. The lower occurrence of hyperlipidaemia/dyslipidaemia in patients with autoantibodies, in comparison to patients without the antibodies, suggests that these antibodies have a role in vascular damage.

Adult↗
PubMed1995

C4 null alleles in a Swedish population.

The distribution of C4 null alleles (C4Q0) was studied in a Swedish population comprising 410 male individuals from Stockholm County and Uppsala City. The prevalances of homozygous C4A*Q0 and C4B*Q0 determined by analysing the gene products in serum were 5.0 and 5.6%, respectively, in the Stockholm population and 4.0% each in the Uppsala population. These values are higher than those previously reported from other Caucasian populations. The finding reflects a different genetic composition of the Swedish population and may have relevance to the disease spectrum in this population as compared to other Caucasian populations.

Adult↗
PubMed1993

Platelets in essential hypertension.

The ultrastructure and adenosine diphosphate induced aggregatory response of platelets of 39 patients with essential hypertension have been studied. Both, transmission and scanning electron microscopy showed the co-existence of various morphological forms of platelets suggestive of activation. The hypertensive platelets also exhibited increased sensitivity to ADP induced aggregation confirming the activated state of platelets; the degree of activation correlated well with the levels of diastolic blood pressure.

Adenosine Diphosphate↗
PubMed1993

Cellular immune response of patients with uveitis to peptide M, a retinal S-antigen fragment.

Peptide M, an 18-amino acid fragment from position 303 to position 320 of retinal S-antigen, produces experimental autoimmune uveitis (EAU), similar to that produced by native S-antigen, in several vertebrate species including nonhuman primates. It was observed that 12 of the 39 (30.7%) patients with uveitis, 1 of the 29 (3.4%) patients with systemic connective tissue disorders (CTD) without eye involvement, 2 of the 7 (5.8%) patients of CTD with uveitis, 1 of the 17 (5.8%) patients with diabetic retinopathy, and none of the 19 normal healthy controls showed a significant lymphoproliferative response to peptide M (stimulation index of 3 or more). Yeast histone H3 peptide gave a positive response in 1 (2.5%), 2 (6.8%), 1 (14.2%), 2 (11.7%), and 2 (10.5%) individuals, respectively, in the different groups studied. In a few cases a positive response to yeast histone H3 peptide was observed without significant stimulation to peptide M. These findings indicate that peptide M could also be an immunogenic epitope of S-antigen in humans and be aetiopathologically related to uveitis in a subset of patients with this disease. However, unlike experimental animals, the responses to peptide M and yeast histone H3 were nonconcordant, necessitating further studies.

Adolescent↗
PubMed1991

Simultaneous determination of centbutindole and its hydroxy metabolite in serum by high-performance liquid chromatography.

A high-performance liquid chromatographic assay has been developed and validated for the determination of centbutindole and its hydroxy metabolite in serum. The method involves extraction of serum samples with diethyl ether at pH greater than 8, back-extraction into 0.5 M hydrochloric acid and finally again with diethyl ether after addition of 2 M potassium hydroxide. Separation was accomplished by reversed-phase high-performance liquid chromatography on a cyano column with an acetonitrile-phosphate buffer system. The recovery of centbutindole and its metabolite was always greater than 80%. Calibration curves were linear over the concentration range 0.25-5 ng/ml for centbutindole and 0.05-1 ng/ml for the hydroxy metabolite. Although the lower limit of detection was 0.1 ng/ml for centbuntindole and 0.02 ng/ml for the hydroxy metabolite, the reliable limits of quantitation were 0.25 and 0.05 ng/ml, respectively, using 4 ml of serum.

Antipsychotic Agents↗
PubMed1991

Japanese B encephalitis with neurocysticercosis.

A case of Japanese encephalitis (JE) with multiple calcified lesions suggestive of calcified neurocysticercosis on CT scan of the head is reported. The presence of nonenhancing calcified lesions and rising antibody titres for JE differentiated it from acute encephalitis neurocysticercosis. Post mortem studies indicate that neurocysticercosis predisposes to fatal JE infection. The present report is of an association of the two diseases which did not result in a fatal outcome.

Adolescent↗
PubMed1990

Kinetics of serotonin in platelets in essential hypertension.

In a study of the kinetics of 5-hydroxytryptamine (5-HT) in platelets in 26 hypertensive subjects with a mean systolic and diastolic blood pressure of 153.9 +/- 26.9 and 106.9 +/- 9.1 mm Hg respectively, it has been observed that in hypertensive platelets there was a marked decrease in 5-HT uptake and content, an increase in 5-HT efflux and an accompanying increase in Plasma 5-HT and 5-HIAA levels. Regression analysis of the data indicated a significant correlation between rise in diastolic blood pressure and these changes in 5-HT kinetics.

Blood Platelets↗
PubMed1990

Clinical evaluation of chandonium iodide as a nondepolarising muscle relaxant.

The effect of chandonium iodide (as a non-depolarising muscle relaxant) was studied in 50 patients of ASA grade I or II who were scheduled for surgery. The patients were divided into 2 groups according to the dose of chandonium iodide (0.2 and 0.25 mg/kg respectively). The onset and duration of action was found to be dose dependent. Intubation characteristics were good to fair in all the patients, the reaction to intubation being either absent or mild. There was mild and transient rise in pulse and blood pressure. No allergic reaction was observed in any patient and reversal characteristics were good in all the cases.

Adult↗
PubMed1989

Clinical trials with gugulipid. A new hypolipidaemic agent.

Multicentric clinical trials of the efficacy of gugulipid conducted at Bombay, Bangalore, Delhi, Jaipur, Lucknow, Nagpur and Varanasi have been reported. Two hundred and five patients completed 12 week open trial with gugulipid in a dose of 500 mg tds after 8 week diet and placebo therapy. One patient showed gastrointestinal symptoms which did not necessitate withdrawal of the drug. A significant lowering of serum cholesterol (av. 23.6%) and serum triglycerides (av. 22.6%) was observed in 70-80% patients Double-blind, crossover study was completed in 125 patients with gugulipid therapy and in 108 patients with clofibrate therapy. Two patients had flu-like syndrome with clofibrate and opted out from the study. With gugulipid the average fall in serum cholesterol and triglycerides was 11 and 16.8% respectively and with clofibrate 10 and 21.6% respectively. The lipid lowering effect of both drugs became evident 3-4 week after starting the drug and had no relationship with age, sex, and concomitant drug intake. Hypercholesterolaemic patients responded better to gugulipid therapy than hypertriglyceridaemic patients who responded better to clofibrate therapy. In mixed hyperlipidaemic patients response to both drugs was comparable. HDL-cholesterol was increased in 60% cases who responded to gugulipid therapy. Clofibrate had no effect on HDL-cholesterol. A significant decrease in LDL-cholesterol was observed in the responder group to both drugs.

Adult↗