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Biomedical subjects

N Valecha

Publications and source records attributed to N Valecha.

30 records · Page 2Linked to original sources
PubMed1993

In vitro activity of fluoroquinolones against chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum.

The in vitro activity of three fluoroquinolones--ciprofloxacin, norfloxacin and ofloxacin--was studied on four laboratory-adapted strains (one chloroquine-resistant) and one fresh isolate of P. falciparum from Delhi by the schizont maturation inhibition microtest. The IC50 concentrations (mean +/- SD) were found to be as: ciprofloxacin 6.38 +/- 1.34 micrograms/ml, norfloxacin 11.24 +/- 1.27 micrograms/ml, and ofloxacin 22.3 +/- 3.11 micrograms/ml, while the MIC values were 32 micrograms/ml, 64 micrograms/ml and 128 micrograms/ml for the three drugs in the same order. The IC50 and MIC values for chloroquine-resistant strain were not significantly different from those for the chloroquine-sensitive strains. We conclude that there is little interstrain variability in the in vitro susceptibility of P. falciparum to fluoroquinolones, and that there is no cross resistance between them and chloroquine. The reported variability in clinical response of falciparum malaria to fluoroquinolones is not likely to be due to variation in parasite sensitivity.

Animals↗
PubMed1993

Curative efficacy of norfloxacin in falciparum malaria.

Fifteen patients of uncomplicated falciparum malaria from Delhi were treated with norfloxacin (10 with 400 mg, 5 with 800 mg, both twice daily) for 3 days and the response was measured according to the WHO extended in vivo test criteria. The lower dose produced S response in two, RII response in five and RIII response in three patients, while the higher dose produced S response in four and RI response in one patient. In patients with S or RI response, the parasite clearance time was 68.6 +/- 9.1 h the defervescence time being 48 h. Thus, norfloxacin did reveal in vivo activity in falciparum malaria, but a dose of 400 mg twice daily proved to be curative only in a small percentage of cases and not consistently. Nausea and bitter taste were the only side effects noted in two patients.

Adolescent↗
PubMed1992

Reversal of chloroquine resistance with verapamil in P. berghei in vivo.

The effects of verapamil on the parasite susceptibility to chloroquine were examined in mice infected with chloroquine-sensitive and chloroquine-resistant lines of Plasmodium berghei. Verapamil in a dose of 10-50 mg/kg daily s.c. for 4 days did not affect the growth of both sensitive and resistant parasites. When verapamil in the same dose range was combined with 1.5 mg/kg chloroquine diphosphate, the chloroquine-sensitive parasites became more susceptible to chloroquine. Similarly, verapamil severely suppressed the growth of chloroquine-resistant parasites in combination with 3 mg/kg (base) of chloroquine, but the reversal of resistance was not complete. Thus, still higher doses of verapamil, which are not tolerated by the host, are required for the complete reversal of resistance.

Animals↗
PubMed1990

Single dose pharmacokinetics of lithium and prediction of maintenance dose in manic depressive patients.

Pharmacokinetics of lithium was studied in 60 manic-depressive patients after an initial dose of 900 mg, in serial blood samples for 24 h. The values (mean +/- SD) obtained were peak serum Li concentration 0.81 +/- 0.18 mEq/l; time to peak 2.57 +/- 0.87 h; total Li clearance 33.2 +/- 15.5 ml/min; volume of distribution 0.62 +/- 0.26 l/kg; elimination rate constant 0.0514 +/- 0.02 h; area under serum concentration-time curve 16.41 +/- 11.41 mEq/1 h; serum half life 15.34 +/- 6.06 h. Thereafter, the applicability of various dose prediction methods was evaluated vis-a-vis the actual doses needed to attain steady state serum lithium concentration of 0.6-1.2 mEq/l in 46 patients. The method based on body weight was not found suitable. A nomographic method predicted higher doses in 27 patients, while Zetin's mathematical model predicted dose was in the range of +/- 150 mg of the actual dose in 21 patients. A method for predicting maintenance dose based on 24 h serum lithium level and body weight is suggested.

Adult↗
PubMed1990

Influence of clonidine, methyldopa and propranolol on acute toxicity of fenitrothion in mice.

The effect of pretreatment with clonidine, methyldopa and propranolol, and of atropine was studied in mice on acute toxicity of fenitrothion, the active ingredient of TIK-20. Atropine significantly decreased and propranolol somewhat decreased the fenitrothion induced death in mice. Clonidine and methyldopa somewhat increased the percentage mortality due to fenitrothion.

Animals↗
PubMedDate not supplied

Comparative bioequivalence study of different brands of acetyl salicylic acid in human volunteers.

A double blind cross over randomized study was conducted in 7 normal healthy volunteers. Single dose (700 mg) of buffered aspirin or aspirin with calcium carbonate or aspirin with caffeine was administered orally, at least 3 days apart. Blood samples were drawn at different time intervals after administration of drug for estimation of salicylate levels. The values of different pharmacokinetic parameters (AUC0-infinity, Cmax and tmax) did not show any significant difference, suggesting that these three brands of aspirin are biologically equivalent.

Adult↗
PubMedDate not supplied

Malaria diagnosis by field workers using an immunochromatographic test.

A rapid immunodiagnostic test (ICT Malaria PfTest) has been developed by ICT Diagnostics (Sydney, Australia) for the diagnosis of Plasmodium falciparum infection. The test is an antigen capture assay based on the detection of P. falciparum histidine-rich protein 2 in peripheral blood. This study was undertaken to assess the performance and usefulness of the test as a diagnostic method in highly malarious, inaccessible forested villages of Mandla district, central India. In all, 353 patients with fever were scanned by the test in parallel with thick blood film examination. The sensitivity and specificity were 100% and 84.5%, respectively. The whole test took about 5 min. The test results became negative in most cases (70%) within 7 d after initiation of curative chemotherapy. The test is simple, easy to learn and accurate, and may prove to be an important tool in the battle against falciparum malaria.

Chromatography↗
PubMedDate not supplied

Ahaptoglobinemia (HpO) and malaria in India.

Haptoglobin (Hp) polymorphism analysed among P. vivax and P. falciparum patients and malaria negative subjects from areas with different epidemiological situations had shown high incidence of ahaptoglobinemia (HpO) among malaria patients. A definite association of HpO with P. vivax as well as P. falciparum malaria in Indian subjects had been observed. However, low sensitivity and reliability of HpO index indicates that it can not be a good indicator for determination of malaria endemicity. About 75 per cent of HpO subjects with P. vivax infection when treated with chloroquine showed typable Hp polymorphs by 8-9 days of post-treatment.

Haptoglobins↗