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Biomedical subjects

N Nanda

Publications and source records attributed to N Nanda.

At least 19 recordsLinked to original sources
PubMed2005

PCR-RFLP of mitochondrial cytochrome oxidase subunit II and ITS2 of ribosomal DNA: markers for the identification of members of the Anopheles culicifacies complex (Diptera: Culicidae).

Anopheles culicifacies Giles is a complex of five sibling species, provisionally designated as species A, B, C, D and E. Species A, C, D and E are vectors of malaria in India. Species A, B, C and D can be identified by polytene chromosome examination except in areas where species B and E are sympatric. Species B and E share the same configuration of the polytene chromosomes but can be differentiated by examining the mitotic chromosomes of F(1) progeny from field collection. Further, polytene chromosome examination method requires the mosquitoes to be at the semigravid stage, which limits on use of this method to a very small proportion of the population. The present study investigated whether the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method can be used to differentiate the members of this complex. Complete ITS2 region along with part of the 5.8S and 28S rDNA sequences (512 bp) and the mitochondrial cytochrome oxidase II (530 bp) were amplified and digested with different restriction endonucleases. The Alu I digest of the COII amplicon and Rsa I digest of the ITS2 amplicon could distinguish two categories: species A and D forming one category and species B, C and E forming another. Further, Dde I digestion of the COII amplicon could distinguish species E from species B and C within the latter category. The PCR-RFLP techniques developed in this study can be applied to areas where species A and B and species B and E are sympatric.

Animals↗
PubMed2004

An allele-specific polymerase chain reaction assay for the differentiation of members of the Anopheles culicifacies complex.

Anopheles culicifacies, the principal vector of malaria in India, is a complex of five cryptic species which are morphologically indistinguishable at any stage of life. In view of the practical difficulties associated with classical cytotaxonomic method for the identification of members of the complex, an allele-specific polymerase chain reaction (ASPCR) assay targeted to the D3 domain of 28S ribosomal DNA was developed. The assay discriminates An. culicifacies species A and D from species B, C and E. The assay was validated using chromosomally identified specimens of An. culicifacies from different geographical regions of India representing different sympatric associations. The assay correctly differentiates species A and D from species B, C and E. The possible use of this diagnostic assay in disease vector control programmes is discussed.

Alleles↗
PubMed2003

Effect of edifenphos on compensatory ovarian hypertrophy, follicular kinetics and estrous cycle in hemicastrated rats.

Edifenphos, an organophosphate fungicide, was administered to hemicastrated albino rats intraperitoneally for 15 consecutive days in graded doses of 2 to 8 mg/kg body weight. In the oil-treated hemicastrated control group, ovarian weight and total number of healthy and atretic follicles were significantly higher than the same parameters in sham-operated control animals, and the estrous cycle was normal. Treatment with 2, 4, 6, or 8 mg/kg/d edifenphos significantly decreased ovarian weight (-6.75, -9.79, -18.71, and -34.13 percent, respectively) below that of the controls. Although treatment with 2 or 4 mg/kg/d edifenphos did not change the number of healthy and atretic follicles, a dosage of 4 mg/kg/d significantly decreased the number and duration of estrous cycles. Treatment with 6 or 8 mg/kg/d, however, significantly decreased the number and duration of different phases of the estrous cycle as well. In all treated groups, the weights of the thymus and uterus were significantly reduced when compared with those of hemicastrated oil-treated control animals.

Animals↗
PubMed2003

House-scale evaluation of bifenthrin indoor residual spraying for malaria vector control in India.

In an area of India where the main rural malaria vector, Anopheles culicifacies Giles, has developed triple resistance to DDT, HCH, and malathion sprayed indoors in antimalaria program, bifenthrin (10% wettable powder) was evaluated in a randomized house-scale trial between July 1999 and March 2000. Entomological impact of four serial doses of bifenthrin (25, 50, 100, and 200 mg/m2) sprayed in rooms in five villages was compared with malathion (2 g/m2) and unsprayed control. An. culicifacies was 100% susceptible to bifenthrin (0.1%), but only 57% to malathion (5%) test papers. Contact bioassays were carried out on sprayed surfaces for 24 wk, and 24 h mortality in An. culicifacies was recorded. Bifenthrin 100- and 200-mg doses caused > or = 80% mortality until 24 wk. The 50-mg dose caused > or = 80% mortality on tin, wood, and mud surfaces for 24 wk, and on brick walls for 16 wk. Bifenthrin 25-mg dose produced > or = 80% mortality for 24 wk on tin, 20 wk on mud walls, 16 wk on brick walls, and 8 wk on wood surfaces. Persistence of > or = 80% mortality did not differ for 25- and 50-mg doses on any surface except on wood (P < 0.05). Malathion sprayed in three rounds of 6 wk apart caused > or = 80% mortality for 16 wk on the brick and mud walls, and for 20 wk on the tin and wood surfaces. Bifenthrin 25- and 50-mg doses produced a similar impact on the densities of An. culicifacies and other mosquitoes but a superior one to malathion or control. Bifenthrin 25-mg dose caused least excitorepellency. Overall, efficacy of bifenthrin was superior to malathion. Considering the duration of the persistence of significant insecticidal action of bifenthrin on the most common surfaces (mud and brick walls), least excito-repellency and a relative impact on the mosquito densities, the 25-mg dose was the most superior among all the four doses evaluated.

Air Pollution, Indoor↗
PubMed2001

Targeted inactivation of Gh/tissue transglutaminase II.

The novel G-protein, G(h)/tissue transglutaminase (TGase II), has both guanosine triphosphatase and Ca(2+)-activated transglutaminase activity and has been implicated in a number of processes including signal transduction, apoptosis, bone ossification, wound healing, and cell adhesion and spreading. To determine the role of G(h) in vivo, the Cre/loxP site-specific recombinase system was used to develop a mouse line in which its expression was ubiquitously inactivated. Despite the absence of G(h) expression and a lack of intracellular TGase activity that was not compensated by other TGases, the Tgm2(-/-) mice were viable, phenotypically normal, and were born with the expected Mendelian frequency. Absence of G(h) coupling to alpha(1)-adrenergic receptor signaling in Tgm2(-/-) mice was demonstrated by the lack of agonist-stimulated [alpha-(32)P]GTP photolabeling of a 74-kDa protein in liver membranes. Annexin-V positivity observed with dexamethasone-induced apoptosis was not different in Tgm2(-/-) thymocytes compared with Tgm2(+/+) thymocytes. However, with this treatment there was a highly significant decrease in the viability (propidium iodide negativity) of Tgm2(-/-) thymocytes. Primary fibroblasts isolated from Tgm2(-/-) mice also showed decreased adherence with culture. These results indicate that G(h) may be importantly involved in stabilizing apoptotic cells before clearance, and in responses such as wound healing that require fibroblast adhesion mediated by extracellular matrix cross-linking.

Animals↗
PubMed2000

GTP binding and signaling by Gh/transglutaminase II involves distinct residues in a unique GTP-binding pocket.

G(h) is a dual function protein. It has receptor signaling activity that requires GTP binding and Ca(2+)-activated transglutaminase (TGase) activity that is inhibited by GTP binding. G(h) shows no homology with other GTP-binding proteins, and its GTP-binding site has not been defined. Based on sequence analysis of [alpha-(32)P]GTP-photolabeled and proteolytically released internal peptide fragments, we report localization of GTP binding to a 15-residue segment ((159)YVLTQQGFIYQGSVK(173)) of the G(h) core domain. This was confirmed by site-directed mutagenesis; a G(h)/fXIIIA chimera (in which residues 162-179 of G(h) were substituted with the equivalent but nonhomologous region of the non-GTP-binding TGase factor XIIIA) and a G(h) point mutant, S171E, retained TGase activity but failed to bind and hydrolyze GTP and did not support alpha(1B)-adrenergic receptor signaling. Slight impairment of GTP binding (1.5-fold) and hydrolysis (10-fold) in the absence of altered TGase activity did not affect signaling by the mutant K173N. However, greater impairment of GTP binding (6-fold) and hydrolysis (50-fold) abolished signaling by the mutant K173L. Mutant S171C exhibited enhanced GTP binding and signaling. Thus, residues Ser(171) and Lys(173) are critical for both GTP binding and signaling but not TGase activity. Mutagenesis of residues N-terminal to Gly(170) impaired both GTP binding and TGase activity. From computer modeling of G(h), it is evident that the GTP-binding region identified here is distinct from, but interacts with, the TGase active site. Together with structural considerations of G(h) versus other GTP-binding proteins, these findings indicate that G(h) has a unique GTP-binding pocket and provide for the first time a mechanism for GTP-mediated regulation of the TGase activity of G(h).

Amino Acid Sequence↗
PubMed2000

Cytotaxonomic evidence for the presence of Anopheles nivipes in India.

Anopheles philippinensis mosquitoes were collected from 5 states in India: Assam, Meghalaya, Arunachal Pradesh, Manipur, and Nagaland. Half-gravid females were examined for variations in wing venation using the presector dark mark on vein I and polytene chromosomes derived from ovarian nurse cells. Polytene chromosomes were examined for diagnostic inversions, t on chromosome arm 2 and I on arm 5. Based on wing characteristics, both An. philippinensis and An. nivipes were identified. Polytene chromosome examinations revealed that all specimens from these 2 populations had 2t; 51 inversion genotype, a diagnostic character for An. nivipes. The wing character was not diagnostic; therefore, it was concluded that all the specimens examined were actually An. nivipes and not An. philippinensis. Further, the X chromosome was of x+b type, that is, the standard arrangement with reference to the inversion b, reported in the An. nivipes population in Thailand. This is the 1st report that unequivocally establishes the occurrence of An. nivipes in India and also shows that the adult wing character is not reliable in distinguishing An. philippinensis from An. nivipes, as has been observed in Thailand.

Animals↗
PubMed2000

Studies on Anopheles fluviatilis and Anopheles culicifacies sibling species in relation to malaria in forested hilly and deforested riverine ecosystems in northern Orissa, India.

In a malaria-endemic region in northwestern Orissa, India, a longitudinal study was undertaken to delineate information on the sibling species of Anopheles fluviatilis and Anopheles culicifacies and their bionomics and role in malaria transmission in forested and deforested ecosystems. In forested villages, An. fluviatilis sibling species S (97.97%) and T (2.02%) were present. The former was highly anthropophagic (human blood index 0.88). Among the sibling species of An. culicifacies, species B (27.96%), C (71.1%), and B/C heterozygotes (0.94%) were present and were highly zoophagic. In deforested riverine villages An. fluviatilis was nearly absent and An. culicifacies sibling species A (0.48%), B (21.1%), C (77.94%), and B/C heterozygotes (0.48%) were present. In forested villages, the annual parasite incidence (269 cases/1,000) and the slide positivity rate (45%) were significantly higher than those in deforested areas, which had values of 39 cases/1,000 and 27%, respectively. The study showed that the high endemicity of malaria in the forested villages was due primarily to 2 vectors, the high rate of anthropophagy of An. fluviatilis species S, and also the more favorable ecological conditions for this vector.

Animals↗
PubMed2000

Investigation of malaria prevalence at National Thermal Power Corporation, Shaktinagar, Sonbhadra District (Uttar Pradesh), India.

Malaria in industrial complexes is promoted by extensive mosquitogenic potential generated by excavations and importation of parasite through migratory labor. The National Thermal Power Corporation (NTPC), Shaktinagar, Sonbhadra district was surveyed for malariogenic conditions from 1994 to 1996. The major mosquito breeding sites were drains, storm-water drains, lakes, outside tanks, overhead tanks, sluice-valve chambers, ornamental tanks, wells, pit wells and water reservoirs, etc. Anopheles culicifacies was the major vector of malaria in this area. Sibling species identification of An. culicifacies revealed that species C predominated during the transmission season and responsible to transmit malaria. Insecticide susceptibility tests against An. culicifacies sl showed that An.culicifacies population was 100% susceptible to malathion, fenitrothorn and deltamethrin while it was found 44% resistant to DDT. The malaria cases recorded in 1994, 1995 and 1996 were 847, 590 and 409 respectively. In vitro study on P. falciparum cases showed that 41, 70, 50% of the isolates tested were resistant to chloroquine in 1994, 1995 and 1996 respectively while an in vivo follow-up study showed 20-30% P. falciparum cases resistant to chloroquine. An integrated approach involving alternate vector control measures along with judicious use of insecticides has been suggested to bring down malaria in industrial complexes.

Animals↗
PubMed1999

Organization and chromosomal mapping of mouse Gh/tissue transglutaminase gene (Tgm2).

The mouse Gh/tissue transglutaminase gene (Tgm2), coding a dual-function protein that both binds guanosine triphosphate (GTP) and catalyzes the posttranslational modification of proteins by transamidation of glutamine residues, has been cloned. Sequence analysis of Tgm2 and comparison with the TGase sequences of other species allowed correction of several apparent sequencing artifacts in the Tgm2 cDNA. Tgm2 spans approximately 34 kb and has 13 exons and 12 introns. Although the structure of Tgm2 shows similarity to that of other transglutaminase genes, with introns ranging from 921 bp to >5 kb, several introns differ considerably in size from those of the human Gh gene, TGM2. Tgm2 maps to the distal region of mouse chromosome 2, a region syntenic to human chromosome 20q containing TGM2. Tgm2 is in the vicinity of two uncloned mouse mutations, diminutive (dm) and blind-sterile (bs). Genomic DNA from dm mice was unavailable; however, Southern blot analysis of bs DNA showed no gross rearrangements of Tgm2.

Amino Acid Sequence↗
PubMed1999

Evidence for a new malaria vector species, species E, within the Anopheles culicifacies complex (Diptera: Culicidae).

Female Anopheles culicifacies Giles from Ramanathapuram district, Tamil Nadu state, India, were examined for oocysts and sporozoites and their larval progeny for mitotic karyotype. Collections were made from Mandapam and Uchipuli on the mainland, and Thangachimadam and Pamban on Rameshwaram Island. Of the 451 An. culicifacies females that were collected and dissected, 24 were found positive for Plasmodia (21 for sporozoites and 3 for oocysts). Both acrocentric and submetacentric Y-chromosome karyotypes were observed among the progeny of females from all villages. All 11 iso-female lines whose parental females were positive for sporozoites or oocysts had progeny with submetacentric Y-chromosomes. Total absence of sporozoite-positives among mothers of acrocentric males was evidence of assortative mating between these 2 sympatric populations (i.e., 2 species). We propose that the nonvector population with acrocentric Y-chromosome sons retain the original designation of species B and that the vector population with the submetacentric Y-chromosome sons be designated as species E, a new species.

Animals↗
PubMed1998

Recommendations for training in performance and interpretation of stress echocardiography. Committee on Physician Training and Education of the American Society of Echocardiography.

Stress echocardiography has emerged as a clinically useful procedure in the management of patients with ischemic heart disease and other conditions. However, the accuracy of this test relies on the ability of those who carry out the technical aspects of the test and depends critically on proper interpretation of the images. Appreciation of wall motion abnormalities is generally acknowledged as one of the most difficult skills to master in echocardiography. There is consensus that this is also one of the most difficult skills to teach. Appreciating stress-induced changes in wall motion, which sometimes are subtle, requires a significant commitment to initial training in this skill and its maintenance. This document provides recommendations for physician training in stress echocardiography.

Cardiology↗
PubMed1998

Increased platelet activation and fibrinogen in Asian Indians. Potential implications for coronary risk.

AIMS: To determine whether Asian Indians (Indians), a group known to have high rates of coronary heart disease, have increased platelet activation and fibrinogen levels relative to white Americans of European origin (whites). METHODS AND RESULTS: Forty healthy, non-smoking Indians, aged 25-45, were matched with 40 healthy whites for age (within 3 years) and gender. Platelet activation was tested in blood exiting a bleeding time wound at 1 and 2 min post-incision (wound-induced activation), as well as in venous blood stimulated in vitro with collagen, using whole blood flow cytometry. Other risk factors, including fibrinogen levels, family history of diabetes or coronary heart disease, fasting insulin and lipid levels, and Lp(a) were also assessed. Fibrinogen levels were higher among Indians than whites, even after adjustment for gender or family history of coronary heart disease (P < 0.05). Indians had higher levels of wound-induced glycoprotein IIb/IIIa binding and platelet secretion (P-selectin expression) than whites, with the greatest differences found when comparing the upper quintile of activation for each group (Ps < 0.05). Indians with a family history of coronary heart disease (n = 15) had higher levels of platelet secretion (wound-induced and in vitro) than Indians without a family history (Ps < 0.05), while the relationship was reversed among whites. Platelet activation measures were not consistently related to other coronary risk factors, while fibrinogen was related to triglyceride and insulin levels among Indians. CONCLUSION: Indians have elevated fibrinogen and platelet activation levels relative to whites. These factors may contribute to the increased coronary risk observed in Indians.

Adult↗
PubMed1998

Studies on bionomics of Anopheles fluviatilis and its sibling species in Nainital district, U.P.

A study on the bionomics of Anopheles fluviatilis sensu lato was carried out in two physiographic regions, viz. Bhabar and Terai of District Nainital, Uttar Pradesh. In both areas, An. fluviatilis was found resting indoors predominantly in cattlesheds. Cytological examination of An. fluviatilis revealed that species T and U were sympatric in Bhabar and Terai villages with predominance of species T. These two sibling species appear to be poor vectors of malaria.

Animals↗
PubMed1997

Y-chromosome polymorphism in species B and C of Anopheles culicifacies complex.

Isofemale cultures of wild-caught Anopheles culicifacies collected from 11 localities representing different ecoepidemiological zones on the mainland of India were identified by examining both F1 male larval mitotic karyotypes and polytene chromosomes of half-gravid F1 adult females. All cultures identified as species A by polytene chromosome examination had submetacentric Y chromosomes. In species B and C, some isofemale cultures had acrocentric Y chromosomes, whereas others were submetacentric. The study revealed the existence of a Y chromosome polymorphism in species B and C; consequently, male mitotic karyotypes are of limited use for differentiating members of the An. culicifacies complex.

Animals↗
PubMed1996

Anopheles fluviatilis complex: host feeding patterns of species S, T, and U.

The host feeding specificity of Anopheles fluviatilis sibling species S, T, and U was determined by analyzing blood meal source using countercurrent immunoelectrophoresis. A distinct difference in the feeding patterns was observed among these species. Species S was found to be predominantly anthropophagic with 91% of the population having fed on human blood. In contrast, species T and U were either exclusively or primarily zoophagic.

Animals↗
PubMed1996

[Echocardiography and aortic dissection].

Echocardiography is the technique most used in the diagnosis of aortic dissection. In this article the echocardiographic signs of aortic dissection are described. The following issues regarding the usefulness of echocardiography in aortic dissection are reviewed as well: detection of entry site, distinction between false and true lumen, assessment of aortic regurgitation, ventricular function, aortic branches involvement, pericardial effusion and follow-up.

Aortic Dissection↗