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Biomedical subjects

V P Sharma

Publications and source records attributed to V P Sharma.

At least 127 records · Page 7Linked to original sources
PubMed1994

Cellular and humoral immune responses to well-defined blood stage antigens (major merozoite surface antigen) of Plasmodium falciparum in adults from an Indian zone where malaria is endemic.

Conserved and variant regions of two blood stage vaccine candidate antigens of Plasmodium falciparum, merozoite surface antigen (MSA-1) and ring-infected erythrocyte surface antigen (Pf155/RESA), have been shown to be immunogenic. However, the relative immunogenicity of these immunogens in different populations has not been studied. The conserved N-terminal region of MSA-1 was investigated for its immunogenicity by studying cellular (T cell) and humoral (B cell) immune responses in P. falciparum-primed individuals, living in malaria-hyperendemic areas (Orissa State, India), where malaria presents an alarming situation. MSA-1-derived synthetic peptides contained sequences that activated T cells to proliferate and release gamma interferon in vitro. There was considerable variation in the responses to different peptides. However, the highest responses (51% [18 of 35] by proliferation and 34% [12 of 35] by gamma interferon release) were obtained with a synthetic hybrid peptide containing sequences from conserved N- and C-terminal repeat regions of MSA-1 and Pf155/RESA, respectively. Antibody reactivities in an enzyme immunoassay of plasma samples from these donors to different peptides used for T-cell activation were heterogeneous. In general, there was poor correlation between DNA synthesis and either gamma interferon release or antibody responses in individual donors, underlining the importance of examining several parameters of T-cell activation to assess the total T-cell responsiveness of a study population to a given antigen. However, the results from our studies suggest that synthetic constructs containing sequences from the N- and C-terminal regions of MSA-1 and Pf155/RESA representing different erythrocytic stages of the P. falciparum parasite are more immunogenic in humans living in malaria-hyperendemic areas of India who have been primed by natural infection.

Adolescent↗
PubMed1994

Peripheral and central conduction studies in neurolathyrism.

To study the involvement of motor and sensory pathways in neurolathyrism, 19 patients with lathyrism from Unnao, India, where lathyrism is endemic, were studied. The mean age of the patients at the time of the onset of illness was 35.8 (range 18-70) years. The mean duration of illness was 15.6 (range 2-30) years. The clinical picture comprised walking difficulty due to stiffness and mild weakness in all 19 patients, cramps in the legs in five, frequency or urgency of micturition in five, and flexor spasms in three. There was pronounced leg spasticity with a mean Ashworth score of 4.1 (range 2.9-5). Central motor conduction to the tibialis anterior muscle (CMCT-TA) was slow in 14 of the 17 patients (21 sides). Slowing of peripheral motor nerve conduction, although less pronounced, was significant in the upper limb in four and the lower limb in seven sides. The tibial somatosensory evoked potentials were normal and peroneal nerve conduction was marginally impaired. Values for CMCT-TA correlated with the degree of spasticity (p < 0.02) whereas weakness, crossed adductor reflexes, and clonus did not. The wide variability of CMCT-TA in lathyrism may be due to involvement of different types of fibres. Large diameter fibre involvement may cause pronounced slowing. Small diameter fibre involvement could produce appreciable spasticity and mild weakness but a lesser degree of slowing or even normal conduction.

Adolescent↗
PubMed1994

Malaria paradigms in India and control strategies.

The paper gives a brief history of malaria control in India through the National Malaria Control Programme (NMCP), National Malaria Eradication Programme (NMEP), implementation of the Modified Plan of Operation (MPO), strengthening of malaria control by launching P. falciparum Containment Programme (PfCP) and the Urban Malaria Scheme (UMS). Making reference to various evaluations of the NMEP, the paper analyses the present malaria situation and brings out reasons demanding change in the strategy of malaria control in consonance with the global malaria control strategy of the World Health Organization (WHO). The epidemiological analysis has revealed that the present adverse malaria situation concentrates mostly under the following five epidemiological paradigms viz. (i) tribal malaria, (ii) rural malaria, (iii) urban malaria, (iv) industrial malaria, and (v) border malaria. Malaria control requires specific approaches and control strategies for each paradigm. We have suggested changes/augmentation in the organizational set-up beginning from NMEP Directorate to the most peripheral health units. The primary responsibility of malaria prevention and control including cost in developmental projects should be shared by the corporate sectors through intersectoral coordination. Residual problems during maintenance phase of the project would come under the general health services. International and bilateral cooperation increases resources availability. The available tools and their rational use for malaria control in different epidemiological paradigms has been discussed with emphasis on integrated control, selective use of chemical insecticides and adoption of cost-effective and sustainable malaria control methods. In this context, intersectoral collaboration, community participation, training, operational research and health education have been discussed as the vital components for effective malaria control.

Communicable Disease Control↗
PubMed1994

Malaria control utilizing Bacillus sphaericus against Anopheles stephensi in Panaji, Goa.

In a large malaria endemic area in Panaji city, Goa, India, the weekly application of the biolarvicide Bacillus sphaericus (Strain 101, Serotype H 5a 5b) at the rate of 1 g/m2 in the main Anopheles stephensi larval habitats, viz., curing waters, masonry tanks, and sump tanks (under construction), from April to December 1993 resulted in a sharp decline in the habitat positivity (range 0.13-8.0%) as compared with the rest of the Panaji (range 2.2-30.6%) where temephos (Abate) was used as the larvicide. Bacillus sphaericus spraying also led to a significant decline in anopheline densities in positive habitats (range 0-7.3/10 dips) as compared with control habitats (range 0.9-53.0/10 dips). Concurrently, malaria incidence observed in the experimental area (slide positivity rate [SPR] range 2.3-7.8%; monthly parasite index [MPI] range 0.18-1.44) was lower than in the control area (SPR range 14.3-25.5%; MPI range 1.75-6.12).

Animals↗
PubMed1994

Comparative toxicity of certain mosquitocidal compounds to larvivorous fish, Poecilia reticulata.

Toxicity of certain mosquitocidal compounds (both larvicides and adulticides) to the larvivorous fish Poecilia reticulata was determined in the laboratory. Among the various chemical insecticides tested, the synthetic pyrethroid deltamethrin was most toxic to fish (LC50 = 0.016 ppm), while the organophosphorus insecticide abate was least toxic (LC50 = 34 ppm). The bioinsecticides Spherix (Bacillus sphaericus) and Bactoculicide (Bacillus thuringiensis H-14) showed highest safety for the fish (LC50 > 1000 mg/litre). Integrated use of larvivorous fish and bioinsecticide in vector control has been suggested.

Animals↗
PubMed1994

Correlation of malaria endemicity with An. culicifacies sibling species composition and malaria antibody profile in district Allahabad (U.P.).

Entomological, parasitological and serological surveys were conducted between October 1989 and November 1990 in 27 villages (population 33,250) belonging to three topographically different areas of district Allahabad, viz. Gangapar, Doaba and Yamunapar. A good correlation existed in all the three areas between malaria incidence vis-a-vis An. culicifacies sibling species composition and malaria antibodies titre in the populations. In Gangapar and Doaba villages, An. culicifacies densities were low and the proportions of vector species A and C were much less than that of species B, the non-vector species. Low endemicity of malaria was supported by low antibody titres observed in the population. In contrast, in Yamunapar villages An. culicifacies densities were high, species A and C together were almost equal to species B, and malaria incidence as well as antibody titre were high. Based on these observations, district Allahabad, Uttar Pradesh, could be divided into two zones, low malaria transmission zone--Gangapar and Doaba areas and high malaria transmission zone--Yamunapar area.

Adolescent↗
PubMed1994

Resting and biting habits of Anopheles sundaicus in Car Nicobar Island.

Resting and biting habits of An. sundaicus were studied in Car Nicobar Island. Results of resting behaviour revealed that although substantial numbers of An. sundaicus rest outdoor, still the species prefer to rest indoors, and much less in human dwellings. High parity rate (73.38%) in An. sundaicus and close contact with man were the factors responsible for high transmission in Car Nicobar. An. sundaicus population in Car Nicobar is susceptible to DDT. Indoor man-biting of An. sundaicus was significantly higher than outdoors and the species showed bimodal biting activity with first peak between 2130 to 2230 hrs and second between 0130 to 0230 hrs. An. sundaicus preferred to feed on people's legs and hands. Due to complex behaviour of An. sundaicus, an integrated approach comprising (i) chemical, (ii) bioenvironmental control, and (iii) personal protection methods was suggested to interrupt malaria transmission in Car Nicobar Island.

Abdomen↗
PubMed1994

Laboratory studies of pyrethroid-netting combinations to kill mosquitoes.

Bioassays of cotton or synthetic netting, impregnated with one of two formulations of deltamethrin or a formulation of lambda-cyhalothrin, showed that the order of merit of these insecticides varied significantly with the type of netting used. Washing reduced the insecticidal power of all combinations of insecticide and netting. Halving the time of exposure and doubling the dose tended to increase the mortality. Different An. stephensi strains varied significantly in susceptibility. Netting (5 to 8 mm mesh) impregnated with deltamethrin was effective in killing mosquitoes which penetrated the netting in search of an animal host.

Analysis of Variance↗
PubMed1994

Two-site immunoradiometric assay (IRMA): detection, efficiency, and procedural modifications.

A 2-site immunoradiometric assay (IRMA) has been done using Anopheles stephensi fed on Plasmodium vivax blood through parafilm to ascertain at what time in the sporogonic cycle circumsporozoite (CS) antigen can be detected, and to detect CS antigen in mosquitoes squashed on filter paper (FP) and cellulose acetate membrane (CAM). The CS antigen was detectable only in mature oocysts, a day prior to sporozoite liberation, and in salivary gland sporozoites. Dissected sporozoites adsorbed on FP/CAM also can be analyzed by IRMA for Plasmodium species identification.

Animals↗
PubMed1993

Probing the combining site of an anti-carbohydrate antibody by saturation-mutagenesis: role of the heavy-chain CDR3 residues.

The carbohydrate-binding site in Fab fragments of an antibody specific for Salmonella serogroup B O-polysaccharide has been probed by site-directed mutagenesis using an Escherichia coli expression system. Of the six hypervariable loops, the CDR3 of the heavy chain was selected for exhaustive study because of its significant contribution to binding-site topography. A total of 90 mutants were produced and screened by an affinity electrophoresis/Western blotting method. Those of particular interest were further characterized by enzyme immunoassay, and on this basis seven of the mutant Fabs were selected for thermodynamic characterization by titration microcalorimetry. With regard to residues that hydrogen bond to ligand through backbone interactions, Gly102H could not be substituted, while several side chains could be introduced at Gly100H and Tyr103H with relatively little effect on antigen binding. There was, however, a preference for nonpolar side chains at position 103H. Substitution of His101H with carboxylate and amide side chains gave mutants with binding affinities approaching that of the wild type; complete side-chain removal by mutation to Gly was tolerated with a 10-fold reduction in binding constant. Analysis of binding by titration microcalorimetry revealed some dramatic thermodynamic changes hidden by the similarity of the binding constants. Similar effects were observed with residue changes in an Arg-Asp salt-bridge at the base of the loop. These results indicate that alterations to higher affinity anti-carbohydrate antibodies are characterized by an enthalpy-entropy compensation factor which allows for fundamental changes in the nature of the binding interactions but impedes engineering for increases in affinity.

Amino Acid Sequence↗
PubMed1993

Clinical aspects of neurolathyrism in Unnao, India.

To study the clinical picture of lathyrism in Unnao, India and compare it with that reported from other endemic areas, 41 patients from Unnao were studied. Their mean age was 42.9 years (range 22-85) and the mean duration of the illness was 17.1 years (range 2-30). They had been regularly consuming Lathyrus Sativus (LS). The patients complained of walking difficulty due to weakness and leg stiffness (32 each), and of frequency of micturition (4). Gait abnormalities included spastic gait (24), toe walking (18) and the necessary use of walking sticks (13). Weakness was mild to moderate, and was less prominent than was spasticity. In 8 patients the physical signs were asymmetrical. Peripheral neuropathy was present in only one patient, but muscle atrophy and widespread fasciculations were not found. A higher frequency of peripheral neuropathy and lower motor neuron involvement has been reported from Bangladesh and Israel. Severe spasticity in the absence of prominent weakness in lathyrism may be due to the involvement of certain specific groups of corticospinal fibres.

Adult↗
PubMed1993

Seasonality of indoor resting mosquitoes in a broken-forest ecosystem of north-western Orissa.

The seasonal prevalence and indoor resting habits of mosquitoes in a broken-forest ecosystem of Orissa, which is known to be endemic for malaria and bancroftian filariasis, have been studied. A total of 15 anopheline spp., 9 Culex spp. and one each of Aedes, Armigeres and Mansonia, were collected. Major species with perennial occurrence were Anopheles culicifacies, An. subpictus, An. annularis, An. vagus, An. pallidus, An. nigerrimus, Culex quinquefasciatus and Cx. tritaeniorhynchus. These species rested more in cattlesheds than in human dwellings, except Cx. quinquefasciatus which was abundant in human dwellings. The prevalence and indoor resting pattern of different species in relation to seasons and other factors were also investigated.

Animals↗
PubMed1993

Feeding preferences of Anopheles sundaicus in Car Nicobar Island.

Host feeding behaviour of An. sundaicus population in Car Nicobar Island was studied by bloodmeal analysis and bait collection. Results indicated the zoophagic nature of the species in different resting sites. However, a human blood index of 0.18 was observed in specimens collected from human dwellings. The highest proportion of females was found positive for porcine antigen. Bait collections also indicated a similar feeding pattern.

Animals↗
PubMed1993

Effect of temperature on toxicity of two bioinsecticides spherix (Bacillus sphaericus) and bactoculicide (Bacillus thuringiensis) against larvae of four vector mosquitoes.

Two bioinsecticide preparations, viz. Spherix (Bacillus sphaericus) and Bactoculicide (Bacillus thuringiensis H-14), were tested in the laboratory against larvae of Anopheles culicifacies, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti at different temperatures. The LCs50 of Spherix against III instar larvae of these species at 27 +/- 2 degrees C were 2.0, 0.19, 0.05 and > 40 mg/litre, respectively and those of Bactoculicide were 0.32, 0.16, 0.06 and 0.03 mg/litre, respectively. The toxicity of two bioinsecticides, especially Spherix, varied to a great extent when the tests were repeated at 21 +/- 2 degrees C and 31 +/- 2 degrees C. At 21 +/- 2 degrees C, Spherix was almost non-toxic against larvae of An. culicifacies and An. stephensi (LC50 > 10 mg/l) but at 31 +/- 2 degrees C the bioinsecticide was highly toxic against An. culicifacies (LC50 = 0.48 mg/litre) and An. stephensi (LC50 = 0.04 mg/litre). A similar effect of the temperature was also observed with Bactoculicide.

Animals↗