Inhibition of N-nitrosobenzylmethylamine metabolism and DNAbinding in cultured rat esophagus by ellagic acid

The effect of ellagic acid (EA), a naturally occurring plantphenol, on the metabolism, DNA binding and DNA adduct formationof N-nitrosobenzylmethylamine (NBMA) in cultured explants ofrat esophagus was investigated. Explants were incubated in mediumcontaining EA at non-toxic concentrations of 10, 50 and 100µM for 16 h, followed by the addition of 1 µM [³H]NBMAand EA for 12 h. Explant DNA was isolated by phenol extractionand hydroxylapatite chromatography, and benzaldehyde formationwas determined by HPLC analysis of the culture medium. EA produceda significant inhibition in the total covalent binding of NBMAmetabolites to DNA and in the production of benzaldehyde inthe medium. After acid hydrolysis of the isolated DNA, the NBMA-DNAadducts were separated by HPLC. EA caused a dose-dependent decreasein the formation of N⁷-methylguanine and O⁶-methylguanine adducts.These results suggest that EA inhibits both the metabolism ofNBMA and the binding of NBMA metabolites to DNA in culturedrat esophagus.     

Performance analysis of different wavelet feature vectors in quantification of oral precancerous condition

This paper presents an automatic method for classification of progressive stages of oral precancerous conditions like oral submucous fibrosis (OSF). The classifier used is a three-layered feed-forward neural network and the feature vector, is formed by calculating the wavelet coefficients. Four wavelet decomposition functions, namely GABOR, HAAR, DB2 and DB4 have been used to extract the feature vector set and their performance has been compared. The samples used are transmission electron microscopic (TEM) images of collagen fibers from oral subepithelial region of normal and OSF patients. The trained network could classify normal fibers from less advanced and advanced stages of OSF successfully.     

Effects of retroviral envelope-protein cleavage upon trafficking, incorporation, and membrane fusion

Retroviral envelope glycoproteins undergo proteolytic processing by cellular subtilisin-like proprotein convertases at a polybasic amino-acid site in order to produce the two functional subunits, SU and TM. Most previous studies have indicated that envelope-protein cleavage is required for rendering the protein competent for promoting membrane fusion and for virus infectivity. We have investigated the role of proteolytic processing of the Moloney murine leukemia virus envelope-protein through site-directed mutagenesis of the residues near the SU-TM cleavage site and have established that uncleaved glycoprotein is unable either to be incorporated into virus particles efficiently or to induce membrane fusion. Additionally, the results suggest that cleavage of the envelope protein plays an important role in intracellular trafficking of protein via the cellular secretory pathway. Based on our results it was concluded that a positively charged residue located at either P2 or P4 along with the arginine at P1 is essential for cleavage.     

Cadmium-induced Oxidative Stress and Evaluation of Embilica Officinalis and Stressroak in Broilers

Cadmium (Cd) toxicity was studied in broilers, and efficacy of Emblica officinalis (500 ppm in feed), vitamin E (300 ppm in feed), and stressroak (1 g/kg feed) were evaluated for prophylactic and therapeutic management of Cd toxicity. One-day-old male broiler chicks were randomly divided into eight groups consisting of 10 chicks in each. Groups 1 and 2 were maintained as plain control and Cd (100 ppm in feed) toxic control (for six weeks). Groups 3, 4, and 5 were maintained on a combination of Cd (100 ppm in feed) and Emblica officinalis, vitamin E, and stressroak for six weeks. Groups 6, 7, and 8 were maintained with Cd for the first four weeks and on Emblica officinalis, vitamin E, and stressroak during the subsequent two weeks without Cd. Body weights, feed consumed, Feed conversion ratio (FCR), and glulathione (GSH) were significantly (P<0.05) decreased, whereas the activities of antioxidant enzymes (catalase and Superoxide dismutase (SOD)) and concentration of Thiobarbituric acid reacting substances (TBARS) were significantly (P<0.05) increased in toxic control group. After treatment with Emblica officinalis, vitamin E, and stressroak in groups 6, 7, and 8 during last two weeks and discontinuation of Cd, the parameters revealed improvement. From this study, it is concluded that Cd induces toxicity by oxidative stress, and supplementing Emblica officinalis, vitamin E, and stressroak in feed is useful in preventing and treating the toxicity.     

Validity of a brief screening instrument—CRAFFT in a multiethnic Asian population

Aim

To validate the CRAFFT screening test, against the DSM IV Axis 1-based diagnostic inventory in a population of adolescents and young adult males in Singapore.

Methods

The 23,248 participants belonged to a cohort of males who had undergone a medical examination prior to enlistment for military service. This study took place between August 2004 and August 2005. Subjects underwent a two-stage assessment and were administered the CRAFFT questionnaire and the Composite International Diagnostic Interview (CIDI).

Results

The mean age of the subjects was 19 years (range, 16 to 26 years). The CRAFFT showed moderately high levels of internal consistency (Cronbach's α = 0.73). The optimum cutoff point for drug-related disorder either abuse or dependence and alcohol-related disorder either abuse or dependence criterions were found at CRAFFT score of 1 or higher.

Conclusion

The CRAFFT test is a valid means of screening adolescents for substance-related disorders in a multiethnic population of adolescent and young adult males.     

Subcutaneous phaeohyphomycosis caused by Cladophialophora boppii

Subcutaneous phaeohyphomycosis is an infection of the skin and subcutaneous tissue, caused by dematiaceous fungi. An adult male presented with a history of multiple reddish nodules over the face and hands. Histopathological examination of the skin biopsies showed a dense granulomatous infiltrate of macrophages, containing intracytoplasmic basophilic bodies throughout the dermis. Gomori methenamine-silver stained sections revealed yeast cells within macrophages. Multiple cultures on Sabouraud's dextrose agar grew Cladophialophora boppii. The patient was treated with oral itraconazole for a year and the response monitored with dermal ultrasound. This is the first case report of subcutaneous phaeohyphomycosis caused by Cl. boppii in India.     

Membrane alterations and fluidity changes in cerebral cortex during acute ammonia intoxication

Acute ammonia intoxication is known to cause alterations in activities of several membrane bound enzymes like Na+ K+ ATPase, acetylcholine esterase and glutamate uptake in brain. The alteration in these membrane associated activities could be a consequence of altered membrane architecture. To probe this, the effect of pathophysiological concentrations of ammonia on lipid composition and fluidity of membranes isolated from cerebral cortex of rats, were investigated in the present study. Administration of acute doses of ammonium acetate caused depletion of membrane sphingomyelin and cholesterol levels thereby reducing cholesterol: phospholipid (C: PL) ratio. Levels of phosphatidylserine increased while those of phosphatidylcholine and phosphatidylethanolamine remain unaltered. Membrane fluidity estimations using 1,6-diphenyl-1,3,5-hexatriene (DPH), 1-[4-(trimethylammonio)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) indicated no changes in core and surface membrane fluidity following ammonium acetate administration. Acute ammonia toxicity induced no alteration in bulk fluidity but a decrease in annular fluidity of membranes, as determined using pyrene fluorescence. Elevated levels of malondialdehyde and declined level of total thiols in cerebral cortex membranes of rats under acute ammonia intoxication indicated the existence of oxidative stress.