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6
result(s) for
"Dua, Virendra Kumar"
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Malaria-attributed death rates in India
by
Kumar, Ashwani
,
Dua, Virendra Kumar
,
Rathod, Pradipsinh K
in
Antimalarials
,
Humans
,
India - epidemiology
2011
Journal Article
Malaria-attributed death rates in India/Authors' reply
2011
[...] confirmation bias might have led to overdiagnosis of malaria among fever deaths in endemic areas; coding physicians were aware of the state in which each death occurred. [...] although N K Shah and colleagues suggest a case-fatality rate of only 0.1-0.3% for P falciparum, the true risk of death in rural untreated individuals with fever due to P falciparum could well be an order of magnitude higher.
Journal Article
Insecticidal and genotoxic activity of Psoralea corylifolia Linn. (Fabaceae) against Culex quinquefasciatus Say, 1823
2013
BACKGROUND: Indiscriminate use of synthetic insecticides to eradicate mosquitoes has caused physiological resistance. Plants provide a reservoir of biochemical compounds; among these compounds some have inhibitory effect on mosquitoes. In the present study the larvicidal, adulticidal and genotoxic activity of essential oil of Psoralea corylifolia Linn. against Culex quinquefasciatus Say was explored. METHODS: Essential oil was isolated from the seeds of P. corylifolia Linn. Larvicidal and adulticidal bioassay of Cx. quinquefasciatus was carried out by WHO method. Genotoxic activity of samples was determined by comet assay. Identification of different compounds was carried out by gas chromatography- mass spectrometry analysis. RESULTS: LC₅₀ and LC₉₀ values of essential oil were 63.38±6.30 and 99.02±16.63 ppm, respectively against Cx. quinquefasciatus larvae. The LD₅₀ and LD₉₀ values were 0.057±0.007 and 0.109±0.014 mg/cm² respectively against adult Cx. quinquefasciatus,. Genotoxicity of adults was determined at 0.034 and 0.069 mg/cm². The mean comet tail length was 6.2548±0.754 μm and 8.47±0.931 μm and the respective DNA damage was significant i.e. 6.713% and 8.864% in comparison to controls. GCMS analysis of essential oil revealed 20 compounds. The major eight compounds were caryophyllene oxide (40.79%), phenol,4-(3,7-dimethyl-3-ethenylocta-1,6-dienyl) (20.78%), caryophyllene (17.84%), α-humulene (2.15%), (+)- aromadendrene (1.57%), naphthalene, 1,2,3,4-tetra hydro-1,6-dimethyle-4-(1-methyl)-, (1S-cis) (1.53%), trans- caryophyllene (0.75%), and methyl hexadecanoate (0.67%). CONCLUSION: Essential oil obtained from the seeds of P. corylifolia showed potent toxicity against larvae and adult Cx. quinquefasciatus. The present work revealed that the essential oil of P. corylifolia could be used as environmentally sound larvicidal and adulticidal agent for mosquito control.
Journal Article
Anti-malarial activity of Holarrhena antidysenterica and Viola canescens, plants traditionally used against malaria in the Garhwal region of north-west Himalaya
by
Verma, Gaurav
,
Agarwal, Dau Dayal
,
Dua, Virendra K
in
Albinism
,
Animals
,
Antimalarials - isolation & purification
2011
Background
The increasing number of multidrug-resistant
Plasmodium
strains warrants exploration of new anti-malarials. Medicinal plant research has become more important, particularly after the development of Chinese anti-malarial drug artemisnin from
Artemisia annua
. The present study shows evaluation of anti-malarial effects of two plants commonly used against malaria in the Garhwal region of north-west Himalaya, in order to discover the herbal-based medicine.
Methods
In vitro
anti-plasmodial sensitivity of plant extracts was assessed using schizont maturation and parasite lactate dehydrogenase (pLDH) assay. Cytotoxic activities of the examined extracts were determined on L-6 cells of rat skeletal muscle myoblast. The 4-day test for anti-malarial activity against a chloroquine sensitive
Plasmodium berghei
NK65 strain in Swiss albino mice was used for monitoring
in vivo
activity of plant extracts.
Results
Chloroform extract of
H. antidysenterica
(HA-2) and petroleum ether extract of
V. canescens
(VC-1) plants significantly reduced parasitaemia in
P. berghei
infected mice. The extract HA-2 showed
in vitro
anti-plasmodial activity with its IC
50
value 5.5 μg/ml using pLDH assay and ED
50
value 18.29 mg/kg in
P. berghei
infected Swiss albino mice. Similarly petroleum ether extract of
V. canescens
(VC-1) showed
in vitro
anti-plasmodial activity with its IC
50
value 2.76 μg/ml using pLDH assay and ED
50
15.8 mg/kg in
P. berghei
infected mice. The extracts coded as HA-2 at 30 mg/kg and VC-1 at 20 mg/kg exhibited parasite inhibition in mice: 73.2% and 63.0% respectively. Of these two plant extracts, petroleum ether extract of
V. canescens
was found slightly cytotoxic.
Conclusion
The present investigation reflects the use of these traditional medicinal plants against malaria and these plants may work as potential source in the development of variety of herbal formulations for the treatment of malaria.
Journal Article
Anti-malarial property of steroidal alkaloid conessine isolated from the bark of Holarrhena antidysenterica
by
Bagai, Upma
,
Verma, Gaurav
,
Gupta, NC
in
Alkaloids - pharmacology
,
Alkaloids - therapeutic use
,
Alkaloids - toxicity
2013
Background
In the face of chronic and emerging resistance of parasites to currently available drugs and constant need for new anti-malarials, natural plant products have been the bastion of anti-malarials for thousands of years. Moreover natural plant products and their derivatives have traditionally been a common source of drugs, and represent more than 30% of the current pharmaceutical market. The present study shows evaluation of anti-malarial effects of compound conessine isolated from plant
Holarrhena antidysenterica
frequently used against malaria in the Garhwal region of north-west Himalaya.
Methods
In vitro
anti-plasmodial activity of compound was assessed using schizont maturation and parasite lactate dehydrogenase (pLDH) assay. Cytotoxic activities of the examined compound were determined on L-6 cells of rat skeletal muscle myoblast. The four-day test for anti-malarial activity against a chloroquine-sensitive
Plasmodium berghei
NK65 strain in BALB/c mice was used for monitoring
in vivo
activity of compound. In liver and kidney function test, the activity of alkaline phosphatase (ALP) was examined by p-NPP method, bilirubin by Jendrassik and Grof method. The urea percentage was determined by modified Berthelot method and creatinine by alkaline picrate method in serum of mice using ENZOPAK/CHEMPAK reagent kits.
Results
Compound conessine showed
in vitro
anti-plasmodial activity with its IC
50
value 1.9 μg/ml and 1.3 μg/ml using schizont maturation and pLDH assay respectively. The compound showed cytotoxity IC
50
= 14 μg/ml against L6 cells of rat skeletal muscle myoblast. The isolated compound from plant
H
.
antidysenterica
significantly reduced parasitaemia (at 10 mg/kg exhibited 88.95% parasite inhibition) in
P
.
berghei
-infected mice. Due to slightly toxic nature (cytotoxicity = 14), biochemical analysis (liver and kidney function test) of the serum from mice after administration of conessine were also observed.
Conclusion
The present investigation demonstrates that the compound conessine exhibited substantial anti-malarial property. The isolated compound could be chemically modified to obtain a more potent chemical entity with improved characteristics against malaria.
Journal Article
Integration of a Phosphatase Cascade with the MAP Kinase Pathway provides for a Novel Signal Processing Function
by
Chaudhri, Virendra K
,
Dua, Raina
,
Misra, Manjari
in
Combinatorial analysis
,
Kinases
,
Phosphatase
2009
We mathematically modeled the receptor-activated MAP kinase signaling by incorporating the regulation through cellular phosphatases. Activation induced the alignment of a phosphatase cascade in parallel with the MAP kinase pathway. A novel regulatory motif was thus generated, providing for the combinatorial control of each MAPK intermediate. This ensured a non-linear mode of signal transmission with the output being shaped by the balance between the strength of input signal, and the activity gradient along the phosphatase axis. Shifts in this balance yielded modulations in topology of the motif, thereby expanding the repertoire of output responses. Thus we identify an added dimension to signal processing, wherein the output response to an external stimulus is additionally filtered through indicators that define the phenotypic status of the cell.