Enhancement of lipid peroxidation in rat liver on acute exposure to styrene and acrylamide a consequence of glutathione depletion

Lipid peroxidation, glutathione level and activity of glutathione-S-transferase were studied in liver and brain of rats 4 and 3 h after a single i.p. administration of 0, 25, 75, 100 mg/kg acrylamide or 0, 50, 100, 200, 600 mg/kg styrene, respectively. In liver both acrylamide and styrene caused an increase in lipid peroxidation and decrease in glutathione contents and activity of glutathione-S-transferase in a dose dependent manner, while in brain only acrylamide produced a decrease in glutathione content. The decrease in glutathione content was not always associated with increase of lipid peroxidation. The enhancement of lipid peroxidation occurred only when glutathione contents were depleted to certain critical levels. No effect of acrylamide or styrene was seen on lipid peroxidation under in vitro conditions. The addition of glutathione in the incubation mixture significantly inhibited the rate of lipid peroxidation of liver homogenates of acrylamide and styrene treated animals.The results suggest that enhancement of lipid peroxidation in liver on exposure to acrylamide or styrene is a consequence of depletion of glutathione to certain critical levels. The inhibition of glutathione-S-transferase activity by acrylamide and styrene suggests that detoxication of these neurotoxic compounds could be suppressed following acute exposure.     

A rapid and efficient method for the extraction of total DNA from the sweet potato and its related species

Secondary metabolites, latex/mucilagenous secretions, polysaccharides, and proteins interfere with the extraction of high-quality, restrictable total cellular DNA from sweet potato [Ipomoea batatas (L.) Lamk.] and related species. A method for the DNA extraction is described which overcomes these problems.     

Fine needle aspiration cytologic diagnosis of the solitary cold thyroid nodule. Comparison with ultrasonography, radionuclide perfusion study and xeroradiography

Thirty-six cases of solitary and scintigraphically "cold" thyroid nodules were studied by fine needle aspiration (FNA) cytology, ultrasonography, radionuclide perfusion study (RPS) and xeroradiography with the aim of differentiating the neoplastic from the nonneoplastic nodules. Histologic study of the excised specimens provided the definitive diagnosis in all cases. Of the techniques used in this study, FNA cytology and RPS had the highest sensitivities and specificities. Ultrasonography and xeroradiography were of limited use due to their low sensitivity rates.     

Effect of Physical Violence on Sexually Transmitted Infections and Treatment Seeking Behaviour among Female Sex Workers in Thane District,Maharashtra, India

Background

Violence against sex workers can heighten their vulnerability to HIV and other sexually transmitted infections (STIs). Evidence suggests the risk of acquiring STI/HIV infections among female sex workers (FSWs) who have experienced violence to be almost three-times higher than FSWs, who have not experienced violence. Moreover, an experience of physical and sexual violence makes it difficult for them to negotiate safer sex with their partners and often act as a barrier to utilization of prevention services.

Methods

This study utilizes data from 2785 FSWs aged 18 years and above who participated in a cross-sectional behavioural study conducted during 2013–14 in Thane district, Maharashtra. A probability-based two-stage cluster sampling method was used for data collection. This study assesses the effect of physical violence on self-reported STI symptoms (any STI and multiple STIs) and treatment seeking for the last STI symptom using propensity score matching method.

Results

About 18% of sampled FSWs reported physical violence at the time of the survey. The likelihood of experiencing such violence was significantly higher among FSWs who solicited clients at public places, engaged in other economic activities apart from sex work, had savings, and reported high client volume per week. FSWs experiencing violence were also inconsistent condom users while engaging in sex with regular partners and clients. The average adjusted effect of violence clearly depicted an increase in the risk of any STI (11%, p<0.05) and multiple STIs (8%, p<0.10) and reduction in treatment seeking (10%, p<0.05).

Conclusions

This study demonstrates a significant effect of physical violence on reporting of any STI symptom and treatment seeking. Findings call for the immediate inclusion of strategies aimed to address violence related challenges in HIV prevention program currently being provided at Thane district. Such strategies would further help in enhancing the access to tailored STI prevention and care services among FSWs in the district.     

Antiretroviral activity of mechanism-based irreversible inhibitors of S-adenosylhomocysteine hydrolase.

S-Adenosylhomocysteine hydrolase (AdoHcy-nase) is a key enzyme in transmethylation reactions. The objective of the present study was to examine the potential antiretroviral activities of novel mechanism-based irreversible AdoHcy-nase inhibitors. (Z)-4',5'-didehydro-5'-deoxy-5'-fluoroadenosine (ZDDFA), (E)-4',5'-didehydro-5'-deoxy-5'-fluoroadenosine (EDDFA), (Z)-4',5'-didehydro-5'-deoxy-5'-chloroadenosine (ZDDCA) and 5'-deoxy-5'-acetylenic adenosine (DAA) inhibited AdoHcy-nase activity with Ki values of 0.55, 1.04, greater than 10.0 and 3.30 microM, respectively. These four compounds were tested for antiviral activity in vitro against Moloney leukemia virus (MoLV) in the XC-plaque assay. MoLV replication in murine fibroblasts (SC-1) was inhibited by ZDDFA, EDDFA and DAA with IC50 values of 0.05, 0.25 and 3.30 micrograms/ml, respectively. ZDDCA did not inhibit MoLV infection at the concentrations tested. Antiviral activity correlated with the ability of the individual compounds to maintain sustained elevations in intracellular S-adenosylhomocysteine (AdoHcy) concentrations in the SC-1 cells. ZDDFA, the most potent inhibitor of AdoHcy-nase and MoLV was also the most active in maintaining sustained elevations in intracellular AdoHcy levels. The antiviral activity of ZDDFA was also examined in murine C3H1OT1/2 fibroblasts which constitutively produce MoLV. Pretreatment with ZDDFA (1.0 microgram/ml) for 24 hr inhibited virus production by 88%. Similar to the SC-1 cells, and concomitant with enzyme inhibition, there was a 300-fold increase in AdoHcy levels in ZDDFA (1.0 microgram/ml) treated C3H1OT1/2 cells. Incorporation of a [3H]methyl group from tritiated S-adenosylmethionine into total RNA in C3H1OT1/2 cells was inhibited by ZDDFA without affecting cell viability. These results suggest that mechanism-based inhibitors of AdoHcy-nase, such as ZDDFA, may have potential as antiretroviral agents.     

Possible role of metal ionophore against zinc induced cognitive dysfunction in <Emphasis Type=SmallCaps>d-</Emphasis>galactose senescent mice

Metal ionophores are considered as potential anti-dementia agents, and some are currently undergoing clinical trials. Many metals are known to accumulate and distribute abnormally in the aging brain. Alterations in zinc metal homeostasis in the glutaminergic synapse could contribute to ageing and the pathophysiology of Alzheimer’s disease (AD). The present study was designed to investigate the effect of metal ionophores on long term administration of zinc in D-galactose induced senescent mice. The ageing model was established by combined administration of zinc and D-galactose to mice for 6 weeks. A novel metal ionophore, PBT-2 was given daily to zinc-induced d-galactose senescent mice. The cognitive behaviour of mice was monitored using the Morris Water Maze. The anti-oxidant status and amyloidogenic activity in the ageing mouse was measured by determining mito-oxidative parameters and deposition of amyloid β (Aβ) in the brain. Systemic administration of both zinc and D-galactose significantly produced memory deficits, mito-oxidative damage, heightened acetylcholinesterase enzymatic activity and deposition of amyloid-β. Treatment with PBT-2 significantly improved behavioural deficits, biochemical profiles, cellular damage, and curbed the deposition of APP in zinc-induced senescent mice. These findings suggest that PBT-2, acting as a metal protein attenuating compound, may be helpful in the prevention of AD or alleviation of ageing.     

Germinating pigeonpea (Cajanus cajan) seeds secrete factor(s) having antiethylene-like effects

Germinating pigeonpea seeds were found to release factor(s), which dramatically altered the growth pattern of rice seedlings. This included an increased sensitivity of roots to gravity, an increase in seminal root length, and increased density of branch roots on the seminal root and suppression of root hair formation. Furthermore, the known characteristic responses of rice to ethylene (namely, coleoptile growth promotion and induction of senescence) were inhibited by the presence of these factor(s). This altered growth pattern of rice seedlings was similar to that brought about by the ethylene-antagonist, silver nitrate. Further, the change in growth pattern in rice was specifically reversed by ethrel. In addition, in wild-type Arabidopsis thaliana these factors suppressed formation of root hair, the development of which is known to be promoted by ethylene. In contrast, in a mutant A. thaliana which shows constitutive ethylene response ( ctr1-1 ), the factors failed to inhibit root hair formation. These observations indicated that germinating pigeonpea seeds secrete factor(s), which have antiethylene-like effects.     

Role of Novel Multidrug Efflux Pump Involved in Drug Resistance in Klebsiella pneumoniae

Background

Multidrug resistant Klebsiella pneumoniae have caused major therapeutic problems worldwide due to the emergence of the extended-spectrum β-lactamase producing strains. Although there are >10 major facilitator super family (MFS) efflux pumps annotated in the genome sequence of the K. pneumoniae bacillus, apparently less is known about their physiological relevance.

Principal Findings

Insertional inactivation of kpnGH resulting in increased susceptibility to antibiotics such as azithromycin, ceftazidime, ciprofloxacin, ertapenem, erythromycin, gentamicin, imipenem, ticarcillin, norfloxacin, polymyxin-B, piperacillin, spectinomycin, tobramycin and streptomycin, including dyes and detergents such as ethidium bromide, acriflavine, deoxycholate, sodium dodecyl sulphate, and disinfectants benzalkonium chloride, chlorhexidine and triclosan signifies the wide substrate specificity of the transporter in K. pneumoniae. Growth inactivation and direct fluorimetric efflux assays provide evidence that kpnGH mediates antimicrobial resistance by active extrusion in K. pneumoniae. The kpnGH isogenic mutant displayed decreased tolerance to cell envelope stressors emphasizing its added role in K. pneumoniae physiology.

Conclusions and Significance

The MFS efflux pump KpnGH involves in crucial physiological functions besides being an intrinsic resistance determinant in K. pneumoniae.