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Biomedical subjects

V P Sharma

Publications and source records attributed to V P Sharma.

At least 55 records · Page 3Linked to original sources
PubMed1998

Sulfalene concentrations in plasma and blood cells of Plasmodium falciparum malaria cases after treatment with metakelfin using high-performance liquid chromatography.

A reversed-phase high-performance liquid chromatographic method using acetonitrile-methanol-1 M perchloric acid-water (25:9:0.8:95, v/v/v) at a flow-rate of 1.0 ml min(-1) on LiChrospher 100 RP 18 column (250 x 4 mm; 5 microm) with UV (254 nm) detection has been developed for the determination of sulfalene in plasma and blood cells after oral administration of the antimalarial drug metakelfin. Calibration curves were linear in the range 0.5-100 microg ml(-1). The limit of quantification was 50 ng ml(-1). Within-day and day-to-day coefficients of variation averaged 3.84 and 5.31%, respectively. Mean extraction recoveries of sulfalene from plasma and blood cells were 87.21 and 84.65%, respectively. Mean concentrations of sulfalene in plasma of P. falciparum cases on days 2, 7 and 15 were 44.58, 14.90 and 1.70 microg ml(-1), respectively; in blood cells concentrations of sulfalene were 7.77, 3.25 and 0.75 microg ml(-1), respectively, after oral treatment with two tablets (1000 mg) of metakelfin. Significant difference was recorded on day 2 for sulfalene concentration in blood cells of healthy and P. falciparum cases (t=9.49; P<0.001).

Adult↗
PubMed1998

Chromatographic studies on the isolation of peroxydisulphate oxidation products of primaquine.

Eight compounds from peroxydisulphate oxidation of primaquine were fractionated on Bio-Gel P-2 column using water as an eluent. A HPLC method employing acetonitrile-methanol-1 M perchloric acid-water (30:7:1:95, v/v) as a mobile phase at 1.0 ml/min on microBondapak reversed-phase column and UV detection at 254 nm was developed for the separation and identification of different oxidation products of primaquine. A combination of Bio-Gel chromatography with reversed-phase HPLC was found to be the most suitable analytical technique for the semipreparative isolation of various products formed from the oxidation. Two oxidation products that were isolated had three or four times higher gametocytocidal activity as compared to primaquine.

Antimalarials↗
PubMed1998

A rapid immunochromatographic test (ICT) for diagnosis of Plasmodium falciparum.

A field study was conducted to assess the sensitivity and specificity of rapid immunodiagnostic test based on detection of Plasmodium falciparum histidine-rich protein-2 (PfHRP-2) in peripheral blood for diagnosis of P. falciparum infection. Evaluation in 173 patients showed that the assay was 98.59% sensitive and 97.1% specific. There was no cross-reactivity with P. vivax. The test was positive in few patients who were found to be negative by microscopy showing the presence of antigen after curative chemotherapy. The test is a valuable diagnostic tool for falciparum malaria, especially in emergency/field situations requiring rapid diagnosis.

Animals↗
PubMed1998

Studies on the Plasmodium vivax relapse pattern in Delhi, India.

A five-year epidemiologic study of patients attending a malaria clinic in Delhi was conducted to find the relapse rate of infections with Plasmodium vivax, its seasonal correlation between the primary infection and subsequent relapses, the duration of the incubation period, and the patterns of relapse. By our definition, the relapse rate ranged from 23% to 44% depending on the duration of follow-up. The relapse pattern observed in the study clearly suggests the existence of both tropical and temperate zone types of P. vivax in the population characterized by distinct incubation periods and the possible existence of P. vivax subpopulations characterized by primary long incubation periods. The implication of different incubating forms of P. vivax on the epidemiology and control of malaria is also discussed.

Animals↗
PubMed1998

Relative efficacy of synthetic pyrethroid-impregnated fabrics against mosquitoes under laboratory conditions.

The efficacy of synthetic pyrethroid-impregnated fabrics was evaluated against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus, under laboratory conditions. Results revealed that delta-methrin was significantly superior in comparison to lambdacyhalothrin and cyfluthrin. Results of bioassay tests revealed that deltamethrin was 1.5 and 1.9 times more effective than lambdacyhalothrin and cyfluthrin, respectively, against An. stephensi exposed to cotton fabric treated at 100 g/m2. Deltamethrin was 3.9 and 4.6 times more effective against Ae. aegypti and 3.53 and 4.0 times more effective against Cx. quinquefasciatus. Of cotton, nylon, polyethylene, and jute fabrics, the cotton was the best on the basis of median lethal dose (LD50) and 95% lethal dose (LD90) values and persistence of insecticide.

Aedes↗
PubMed1998

Evaluation of lambdacyhalothrin-impregnated bednets in a malaria endemic area of India. Part 1. Implementation and acceptability of the trial.

In malaria endemic forested villages in Orissa State, India, a 3-year comparison of nylon nets treated with lambdacyhalothrin at 25 mg/m2, untreated nets, and no nets was carried out. Treated nets retained high insecticidal efficacy for more than 7 months. Nets washed after 3 months of use gave 98% kill in a bioassay with a 3-min exposure. Based on these bioassays during the first year, nets were later reimpregnated at 6-monthly intervals with participation of the users. Compliance with the use of nets was good. Eighty-eight percent of nets were usable even after 3 years. The main benefits perceived by treated net users were reductions in malaria, mosquito bites, head louse infestations, and other nuisance insects. The trial was well accepted by the community. Issues related to social marketing and promotion of nets are discussed.

Animals↗
PubMed1998

Evaluation of lambdacyhalothrin-impregnated bednets in a malaria endemic area of India. Part 2. Impact on malaria vectors.

In malaria endemic villages of the Indian State of Orissa, the impact of bednets treated with lambdacyhalothrin at 25 mg/m2 on malaria vectors was assessed during a 3-year intervention trial beginning in May 1990. The main malaria vector was Anopheles culicifacies with a small contribution from Anopheles fluviatilis. The impregnated bednets caused a significant reduction in vector density as assessed by morning indoor resting catches, man-biting rate, light trapping, the proportion of females engorged with human blood, and the parity rate as compared with villages with untreated or no nets. No statistically significant difference was observed in these parameters between the villages with untreated nets or no nets. The trial demonstrated that the lambdacyhalothrin-treated nets were highly effective against the malaria vectors.

Animals↗
PubMed1998

Evaluation of lambdacyhalothrin-impregnated bednets in a malaria endemic area of India. Part 3. Effects on malaria incidence and clinical measures.

In Indian villages with high malaria endemicity use of nylon bednets treated at 25 mg/m2 at 6-month intervals for 3 years caused significant reductions in malaria incidence, slide positivity rate, slide falciparum rate, annual parasite index, and parasite rate in the entire population, as well as reductions in rates of splenomegaly and anemia in children. In villages with untreated nets, considerable reduction also occurred in these parameters except for the rate of splenomegaly. In the village without nets, a relatively small drop occurred in the parasite rate and anemia but no change occurred in malaria incidence, and an increase occurred in the rate of splenomegaly. The trial thus showed the efficacy of impregnated bednets against malaria in the forested hills of Orissa State where the existing control strategy based on indoor residual spraying of DDT has remained incapable of interrupting malaria transmission.

Anemia↗
PubMed1998

Field trials of biolarvicide Bacillus thuringiensis var. israelensis strain 164 and the larvivorous fish Aplocheilus blocki against Anopheles stephensi for malaria control in Goa, India.

Severe outbreaks of malaria occurred in the coastal villages of the Candolim Primary Health Centre (PHC) of Goa, India, in 1993 and 1994. These outbreaks were associated with accelerated construction activity with an influx of migrant laborers. The weekly application of Bacillus thuringiensis var. israelensis (B.t.i.) strain 164 at 1 g/m2 and introduction of the indigenous larvivorous fish Aplocheilus blocki in major breeding habitats of Anopheles stephensi replaced ongoing DDT spraying and pyrethrum fogging in June 1994. The objective of this study was to evaluate the effects of B.t.i. and larvivorous fish on An. stephensi and subsequent transmission of malaria in the Candolim PHC, Goa, India. In 1995 the populations of an. stephensi in larger habitats (habitats with immatures: t = 5.19, P = 0.0017; immature density: t = 3.57, P = 0.007) and smaller habitats (habitats with immature: t = 3.86, P = 0.005; immature density: t = 4.93, P = 0.002) and malaria incidence declined substantially (malaria cases: chi 2 = 712, P < 0.001; slide positivity rate: chi 2 = 10.36, P < 0.001; annual parasite index; chi 2 = 15.1, P < 0.001), whereas the incidence of malaria continued to increase in other nearby towns.

Animals↗
PubMed1998

Efficacy of neem oil-water emulsion against mosquito immatures.

Neem oil-water emulsion was used in mosquito breeding habitats to find out its larvicidal effect on immatures of different mosquito species. Application of 5% neem oil-water emulsion @ 50 ml/sq m in pools and @ 100 ml/sq m in tanks resulted in 100% reduction of III and IV instar larvae of An. stephensi after 24 h while, against Cx. quinquefasciatus it was 51.6 and 91.2% reduction in the larval density after Day 1 and 14 respectively. Similarly, application of 10% emulsion in desert coolers against Aedes aegypti @ 40 to 80 ml per cooler resulted in complete inhibition of pupal production.

Animals↗
PubMed1998

Species diversity and interspecific associations among mosquitoes in rice agro-ecosystem of Kheda district, Gujarat.

Rice agro-ecosystem of Kheda district in Central Gujarat was inhabited by 14 species of anophelines and 15 species of culicines. Anopheles subpictus and Culex vishnui gr dominated the respective groups. Species diversity in rice fields as well as in associated habitats remained high during non-monsoon (rabi) period. There existed several positive and negative interspecific associations. Malaria vector An. culicifacies showed positive association with An. subpictus, An. annularis, An. pallidus and Cx. quinquefasciatus but was found negatively associated with An. nigerrimus, Cx. vishnui and Cx. tritaeniorhynchus.

Animals↗
PubMed1998

Trial with ParaSight-F in the detection of Plasmodium falciparum infection in Chennai (Tamil Nadu), India.

Efficacy of Plasmodium falciparum histidine-rich protein (HRP-II) based diagnostic test ParaSight-F, was evaluated for diagnosis of P. falciparum malaria at the Malaria Clinic in Malaria Research Centre (Field Station), Chennai, Tamil Nadu. A total of 93 febrile patients were screened in parallel by microscopy and by ParaSight-F. The sensitivity and specificity of the test were 100% for the detection of P. falciparum infection.

Animals↗
PubMed1998

Variations in the response to Bacillus sphaericus toxins in different strains of Anopheles stephensi Liston.

Bacillus sphaericus has a potential of use as a larvicide in water storage practices but no such study has been done against Anopheles stephensi. Baseline susceptibility status of eleven wild and three mutant strains of An. stephensi to Spherix, a formulation of B. sphaericus, strain B-101 (serotype H5a, 5b) was determined to find the variations in the degree of their response to B. sphaericus toxins and to study the possibility of development of resistance. The LC50 and LC90 values of different strains of An. stephensi to B. sphaericus formulation varied from 0.088 to 1.42 mg/l and 0.314 to 10.98 mg/l, respectively. Among all the strains tested, Sarojini Nagar, Delhi strain of An. stephensi (a wild type strain) was least susceptible. Laboratory selection of Sarojini Nagar strain of An. stephensi with B. sphaericus at a concentration of 4 mg/l resulted in the development of a high degree of resistance (LC50 > 1600 mg/l) to B. sphaericus within four generations.

Animals↗
PubMed1998

Mosquito fauna and breeding habitats of anophelines in Car Nicobar Island, India.

A total of 31 species of mosquitoes belonging to 10 genera, i.e. Anopheles, Aedes, Armigeres, Culex, Harpagomyia, Hodgesia, Mansonia, Orthopodomyia, Toxorhynchites and Uranotaenia were collected from Car Nicobar Island. Four Anopheles species, An. barbumbrosus, An. insulaeflorum, An. kochi and An. roperi were recorded for the first time from this Island. An. sundaicus was the most predominant species encountered. The results of the study on anophelines with emphasis on species-specific breeding preference in various aquatic habitats have been recorded.

Animals↗