NISCAIR Online Periodicals Repository Collection: IJEB Vol.44(07) [July 2006]

Molecular characterization of mutation associated with rifampicin and isoniazid resistance in Mycobacterium tuberculosis isolates

Wed, 28 Jun 2006 22:58:59 GMT

Title: Molecular characterization of mutation associated with rifampicin and isoniazid resistance in Mycobacterium tuberculosis isolates

Authors: Negi, Sanjay Singh; Anand, Ranjana; Pasha, S T; Gupta, Sunil; Basir, Seemi Farhat; Khare, Shashi; Lal, Shiv

Abstract: Nucleotide changes in catalase peroxidase (Kat G) gene and gene encoding the beta subunit of RNA polymerase (rpo B), responsible for isoniazid and rifampicin drug resistance were determined in the clinical isolates of Mycobacterium tuberculosis by PCR-RFLP, Line probe assay and DNA sequencing. PCR-RFLP test was performed by HapII cleavage of an amplified fragment of Kat G gene to detect the transversion 315AGC→ACC(Ser→Thr) which is associated with INH drug resistance. The Line probe assay kit was evaluated to detect the mutation in 81bp RMP resistance determining region of rpo B gene associated with RMP drug resistance. These results were validated by DNA sequencing and drug susceptibility test. Kat G S 315 T mutation was found in 74.19% strains of M. tuberculosis from Delhi. This mutation was not found in any of the susceptible strains tested. The line probe assay kit and DNA sequencing identified 18 isolates as RMP resistant with specific mutation, while one of the RMP resistant strain was identified as RMP susceptible, with a concordance of 94.73% with the phenotypic drug susceptibility result. Majority (8 of 19, 42.1%) of resistant isolates involved base changes at codon 531 of rpo B gene. Both PCR-RFLP and Line probe assay test can be used in many of the clinical microbiology laboratories for early detection of isoniazid and rifampicin drug resistance in clinical isolates of M. tuberculosis.

Page(s): 547-553

Erythrocyte antioxidant enzymes in toxicological evaluation of commonly used organophosphate pesticides

Wed, 28 Jun 2006 22:58:59 GMT

Title: Erythrocyte antioxidant enzymes in toxicological evaluation of commonly used organophosphate pesticides

Authors: Singh, Mohan; Sandhir, Rajat; Kiran, Ravi

Abstract: Erythrocytes are excellent models for the study of interactions of xenobiotics with biomembranes. Present work is designed to study the in vitro effects of some organophosphates (ethion, chlorpyrifos, dimethoate and monocrotophos) on rat erythrocytes. Treatment of erythrocytes with organophosphates resulted in decreased erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) activity, whereas activities of glutathione-s-transferase (GST) and glutathione reductase (GR) were increased. Reduced Glutathione (GSH) content of RBCs was decreased after treatment with the pesticides. Increased activities of GST and GR were due to induction of natural defense mechanism of erythrocytes against the toxicity of the pesticides. Membrane bound enzymes like acetylcholinesterase (AChE), Na⁺-K⁺-ATPase and Ca²⁺-ATPase were also inhibited. Altered activities of these enzymes along with decreased GSH content indicate increased oxidative stress in erythrocytes after treatment with organophosphates

Page(s): 580-583

Teratogenicity of Asparagus racemosus Willd. root, a herbal medicine

Wed, 28 Jun 2006 22:58:59 GMT

Title: Teratogenicity of Asparagus racemosus Willd. root, a herbal medicine

Authors: Goel, R K; Prabha, T; Kumar, M Mohan; Dorababu, M; Prakash; Singh, G

Abstract: Asparagus racemosus (AR) is a herb used as a rasayana in Ayurveda and is considered both general and female reproductive tonic. Methanolic extract of A. racemosus roots (ARM; 100 mg/kg/day for 60 days) showed teratological disorders in terms of increased resorption of fetuses, gross malformations e.g. swelling in legs and intrauterine growth retardation with a small placental size in Charles Foster rats. Pups born to mother exposed to ARM for full duration of gestation showed evidence of higher rate of resorption and therefore smaller litter size. The live pup showed significant decrease in body weight and length and delay of various developmental parameters when compared to respective control groups. AR therefore, should be used in pregnancy cautiously as its exposure during that period may cause damage to the offspring.

Page(s): 570-573

A comparative study on the protective effects of 17β-estradiol, biochanin A and bisphenol A on mammary gland differentiation and tumorigenesis in rats

Wed, 28 Jun 2006 22:58:59 GMT

Title: A comparative study on the protective effects of 17β-estradiol, biochanin A and bisphenol A on mammary gland differentiation and tumorigenesis in rats

Authors: Yin, Hong; Ito, Akihiro; Bhattacharjee, Dilip; Hoshi, Masaharu

Abstract: Mammary tissue differentiation and tumorigenesis were studied in female rats following subcutaneous injection at 2, 4 and 6 days after birth with low or high doses of 17β-estradiol (0.1 or 10 µg; E2), biochanin A (0.1 or 10 mg; BCA) or bisphenol A (0.1 or 10.0 mg; BPA). Half of the rats were killed on day 35 to analyze the terminal end bud (TEB), terminal duct (TD) and alveolar bud (AB) of the mammary tissue. The remaining rats were injected, ip, with a dose of 50 mg/kg of N-nitroso-N-methylurea (MNU) at 7 weeks of age and sacrificed 26 weeks later. The incidence and multiplicity of mammary tumors (MT) decreased among all three different treated groups, dose-dependently. However, the pattern of mammary gland differentiation varied. No significant difference was observed after E2 administration. TEB decreased dose-dependently in BCA treated groups and the number of TD and AB were suppressed significantly in BPA high dose group.

Page(s): 540-546