Effect of long-term treatment of two tobacco-specific N-nitrosamines on the vitamin A status of mice

The effect of long-term treatment of two important tobacco-specific N-nitrosamines, N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), on the depot or circulating levels of vitamin A of Swiss and BALB/c male mice was studied. It was observed that treatment of both NNN and NNK in Swiss and BALB/c mice decreased liver vitamin A levels significantly. NNK treatment also caused a decrease in the levels of vitamin A in plasma.     

Mycoplasma pneumoniae Induces Chronic Respiratory Infection, Airway Hyperreactivity, and Pulmonary Inflammation: a Murine Model of Infection-Associated Chronic Reactive Airway Disease

Because chronic Mycoplasma pneumoniae respiratory infection is hypothesized to play a role in asthma, the potential of M. pneumoniae to establish chronic respiratory infection with associated pulmonary disease was investigated in a murine model. BALB/c mice were intranasally inoculated once with M. pneumoniae and examined at 109, 150, 245, 368, and 530 days postinoculation. M. pneumoniae was detected in bronchoalveolar lavage fluid by culture or PCR in 70 and 22% of mice at 109 and 530 days postinoculation, respectively. Lung histopathology was normal up to 368 days postinoculation. At 530 days, however, 78% of the mice inoculated with M. pneumoniae demonstrated abnormal histopathology characterized by peribronchial and perivascular mononuclear infiltrates. A mean histopathologic score (HPS) at 530 days of 5.1 was significantly greater (P < 0.01) than that for controls (HPS score of 0). Serum anti-M. pneumoniae immunoglobulin G was detectable in all of the mice inoculated with M. pneumoniae and was inversely correlated with HPS (r = -0.95, P = 0.01) at 530 days postinoculation. Unrestrained whole-body plethysmography measurement of enhanced pause revealed significantly elevated airway methacholine reactivity in M. pneumoniae-inoculated mice compared with that in controls at 245 days (P = 0.03) and increased airway obstruction at 530 days (P = 0.01). Murine M. pneumoniae respiratory infection can lead to chronic pulmonary disease characterized by airway hyperreactivity, airway obstruction, and histologic inflammation.     

p-Amino salicylic acid — oxidized cellulose system: a model for long term drug delivery

The immobilization of p-amino salicylic acid (PASA) on periodic oxidized cellulose (O.C) as a biocompatible carrier was investigated. The immobilization of the PASA is based on Schiff's base formation between the amino group of PASA and the aldehyde group of O.C. The in vivo and in vitro release of p-amino salicylic acid was studied. Such a system may be useful for the sustained delivery of the drugs in the body, since O.C. itself is a biosoluble carrier.     

Inhibition of motility of hamster spermatozoa by protein tyrosine kinase inhibitors

Genistein, tyrphostin and piceatannol, which are specific inhibitors of protein tyrosine kinase, were screened for their effects on the motility of intact and demembranated hamster spermatozoa. Of the three inhibitors only piceatannol inhibited the motility of intact spermatozoa. None of the inhibitors had any inhibitory effect on the reactivation of motility of demembranated hamster spermatozoa. Taken together these results indicated that a protein tyrosine kinase associated with the membrane of hamster spermatozoa was probably involved in sustenance of hamster sperm motility. Therefore in the present study a membrane-associated protein tyrosine kinase was purified from a detergent-soluble extract of plasma membranes of mature hamster spermatozoa. The purification involved cation exchange chromatography on fast protein liquid chromatography (FPLC) followed by affinity chromatography either on an antiphosphotyrosine antibody agarose or poly glu-tyr agarose column. The pure protein tyrosine kinase had an apparent molecular mass of 45 kDa. The enzyme was not inhibited by genistein or herbimycin but was inhibited by piceatannol. This is the first report on the purification of a sperm plasma membrane-associated protein tyrosine kinase, an enzyme which has also been implicated in hamster sperm motility.     

Risk conferred by tagged SNPs of AGT gene in causing susceptibility to essential hypertension

Introduction: AGT gene harbors several variants of which 21 are found to be in high linkage disequilibrium as per Hapmap database. Studies delineating the importance of these tagged SNPs are very limited and lacking from Indian population. In the present study, we evaluated the contribution of four tagged SNPs namely, g.6635G?>?A, g.6506G?>?A, g.12840G?>?A, and g.13828T?>?C at AGT locus along with the analyses of haplotype and epistatic interactions in causing susceptibility to essential hypertension (EHT).

Methods: About 215 hypertensives and 230 normotensives were genotyped for selected tagged SNPs using PCR-RFLP method.

Results: Significant association was obtained for g.6635G?>?A and g.6506G?>?A polymorphisms wherein GG homozygotes for both the markers were at risk for developing the condition. g.13828T?>?C polymorphism specially, female heterozygotes (TC) were found to be at increased risk for EHT. Haplotype GGGC was found to have a significant protective effect (p?=?0.0059). Markers g.6506G?>?A and g.12840G?>?A resulted in the creation of new enhancer sites thereby affecting splicing process.

Conclusion: The present report is the first one in the literature showing general- and gender-specific association of g.6506G?>?A and g.13828T?>?C polymorphisms, respectively, with EHT. However, further studies for replication of present observations are warranted from other populations and other parts of India.