Short duration of lamivudine for the prevention of hepatitis B virus transmission in pregnancy: lack of potency and selection of resistance mutations.

This study sought to assess the antiviral efficacy of lamivudine (LMV) administered during third trimester to reduce maternal viraemia and to identify the emergence of LMV resistance. A prospective observational analysis was performed on 26 mothers with high viral load (>107 IU/mL). Twenty-one women received LMV (treated group) for an average of 53 days (range 22-88 days), and the remaining five formed the untreated control group. Serum samples from two time points were used to measure HBV DNA levels and antiviral drug resistance. The LMV-treated women achieved a median HBV DNA reduction of 2.6-log10 IU/mL. Although end-of-treatment (EOT) HBV DNA in four (18%) LMV-treated women remained at >10(7) IU/mL (± 0.5 log IU/mL), no mother-to-baby transmission was observed. In contrast, a baby from the untreated mother was HBsAg positive at 9 months postpartum. Four technologies were used for drug resistance testing. Only ultra-deep pyrosequencing (UDPS) was sufficiently sensitive to detect minor viral variants down to <1%. UDPS showed that LMV therapy resulted in increased viral quasispecies diversity and positive selection of HBV variants with reverse transcriptase amino acid substitutions at sites associated with primary LMV resistance (rtM204I/V and rtA181T) in four (19%) women. These viral variants were detected mostly at low frequencies (0.63-5.92%) at EOT, but one LMV-treated mother had an rtA181T variant that increased from 2.2% pretherapy to 25.59% at EOT. This mother was also infected with the vaccine escape variant (sG145R), which was inhibited by LMV treatment. LMV therapy during late pregnancy only reduced maternal viraemia moderately, and drug-resistant viral variants emerged.

Towards the characterization and validation of alcohol use disorder subtypes: integrating consumption and symptom data.

BACKGROUND: There is evidence that measures of alcohol consumption, dependence and abuse are valid indicators of qualitatively different subtypes of alcohol involvement yet also fall along a continuum. The present study attempts to resolve the extent to which variations in alcohol involvement reflect a difference in kind versus a difference in degree. METHOD: Data were taken from the 2001-2002 National Epidemiologic Survey of Alcohol and Related Conditions. The sample (51% male; 72% white/non-Hispanic) included respondents reporting past 12-month drinking at both waves (wave 1: n = 33644; wave 2: n = 25186). We compared factor mixture models (FMMs), a hybrid of common factor analysis (FA) and latent class analysis (LCA), against FA and LCA models using past 12-month alcohol use disorder (AUD) criteria and five indicators of alcohol consumption reflecting frequency and heaviness of drinking. RESULTS: Model comparison revealed that the best-fitting model at wave 1 was a one-factor four-class FMM, with classes primarily varying across dependence and consumption indices. The model was replicated using wave 2 data, and validated against AUD and dependence diagnoses. Class stability from waves 1 to 2 was moderate, with greatest agreement for the infrequent drinking class. Within-class associations in the underlying latent factor also revealed modest agreement over time. CONCLUSIONS: There is evidence that alcohol involvement can be considered both categorical and continuous, with responses reduced to four patterns that quantitatively vary along a single dimension. Nosologists may consider hybrid approaches involving groups that vary in pattern of consumption and dependence symptomatology as well as variation of severity within group.

Phytochemical induction of cell cycle arrest by glutathione oxidation and reversal by N-acetylcysteine in human colon carcinoma cells.

Cancer prevention by dietary phytochemicals has been shown to involve decreased cell proliferation and cell cycle arrest. However, there is limited understanding of the mechanisms involved. Previously, we have shown that a common effect of phytochemicals investigated is to oxidize the intracellular glutathione (GSH) pool. Therefore, the objective of this study was to evaluate whether changes in the glutathione redox potential in response to dietary phytochemicals was related to their induction of cell cycle arrest. Human colon carcinoma (HT29) cells were treated with benzyl isothiocyanate (BIT) (BIT), diallyl disulfide (DADS), dimethyl fumarate (DMF), lycopene (LYC) (LYC), sodium butyrate (NaB) or buthione sulfoxamine (BSO, a GSH synthesis inhibitor) at concentrations shown to cause oxidation of the GSH: glutathione disulfide pool. A decrease in cell proliferation, as measured by [(3)H]-thymidine incorporation, was observed that could be reversed by pretreatment with the GSH precursor and antioxidant N-acetylcysteine (NAC). Cell cycle analysis on cells isolated 16 h after treatment indicated an increase in the percentage (ranging from 75-30% for benzyl isothiocyanate and lycopene, respectively) of cells at G2/M arrest compared to control treatments (dimethylsulfoxide) in response to phytochemical concentrations that oxidized the GSH pool. Pretreatment for 6 h with N-acetylcysteine (NAC) resulted in a partial reversal of the G2/M arrest. As expected, the GSH oxidation from these phytochemical treatments was reversible by NAC. That both cell proliferation and G2/M arrest were also reversed by NAC leads to the conclusion that these phytochemical effects are also mediated, in part, by intracellular oxidation. Thus, one potential mechanism for cancer prevention by dietary phytochemicals is inhibition of the growth of cancer cells through modulation of their intracellular redox environment.

A psychosocial model of sun protection and sunbathing in young women: the impact of health beliefs, attitudes, norms, and self-efficacy for sun protection.

A psychosocial model of sun protection and sunbathing as distinct behaviors was developed on 202 young Caucasian women and replicated in an independent sample (n = 207). Proximal outcomes were intention to sun protect and intention to sunbathe; distal outcomes included sun protection and sunbathing behavior measured 5 months later. Objective risk for skin cancer plus 4 classes of psychosocial variables (sun-protective health beliefs, self-efficacy for sun protection, attitudes toward sunbathing, and norms for sunbathing and sun protection) served as predictors. Sun-protective norms and self-efficacy for sun protection predicted only intention to sun protect; sunbathing norms predicted only intention to sunbathe. Susceptibility and advantages of tanning predicted both intention constructs, which, in turn, predicted behavior. These findings distinguish sun protection from sunbathing and provide a basis for intervention design.

Prospective analysis of comorbidity: tobacco and alcohol use disorders.

Alcohol use disorders (AUD) and tobacco use disorders (TD) frequently co-occur. The authors examined AUD-TD comorbidity over time using a state-trait (ST) model. The ST model represents variance in AUD/TD as a traitlike factor that spans measurement occasion and identifies distinct sources of variance in AUD-TD comorbidity. The ST model was evaluated on 450 young adults (baseline age = 18.5 years; 51% with family history of alcoholism) assessed 5 times over 7 years. The ST model demonstrated superior fit over a first-order autoregressive model. The tendency to diagnose with AUD and TD was partially explained by family history of alcoholism; this relationship was mediated by childhood stressors, alcohol expectancies, and behavioral undercontrol. Results supported a common third-variable influence (vs. directional) model of comorbidity. The ST model is an important conceptual and methodological approach to the prospective study of comorbidity in general.

Transitioning into and out of large-effect drinking in young adulthood.

As individuals age beyond the college years into young adulthood, many exhibit a tendency to moderate or "mature out of" alcohol involvement. The current study classified effect-drinking statuses in young adults and examined transitions among statuses using latent transition analysis, a latent variable state-sequential model for longitudinal data. At 3 occasions over 7 years (Years 1, 4, and 7), 443 men (47%) and women (mean age of both at baseline = 18.5 years; 51% with family history of alcoholism) responded to 3 past-30-day items assessing drinking and subjective effects of drinking: whether the respondent drank alcohol, felt high, and felt drunk. Latent statuses included abstainers (14% at Year 1), limited-effect drinkers (8%), moderate-effect drinkers (23%), and large-effect drinkers (54%). Respondents with family history of alcoholism were less likely to transition out of large-effect drinking than those without family history. Men exhibited more severe initial effect-drinking statuses and lower transition probabilities into less severe effect-drinking statuses than women.

Pitfalls in the use of random amplified polymorphic DNA (RAPD) for fingerprinting of gram negative organisms.

Two arbitrary PCR primers for random amplified polymorphic DNA (RAPD) bacterial fingerprinting were used to test factors which may affect RAPD PCR results. These primers have been used in previously published RAPD fingerprinting studies. As expected, the MgCl2 concentration and template concentration in the reaction mixture may affect the RAPD banding patterns. The results obtained were not comparable between runs when using the Hybaid thermal cycler when all other conditions were kept constant. Addition of DMSO, gelatin and repeated subculturing did not appear to affect the banding patterns. A second set of primers directed against known repetitive sequences in Gram negative bacteria (REP1/REP2 and ERIC2) were examined to compare with RAPD as a means of fingerprinting organisms. The reproducibility was excellent. The results suggest RAPD primers can provide some useful comparative information on suspected related strains when tested on the same day and under the same conditions. PCR using REP1/REP2 and ERIC2 primers may provide a more reliable and reproducible alternative method for fingerprinting Gram negative bacteria.

Evaluation of the Roche Amplicor polymerase chain reaction system for detection of Mycobacterium tuberculosis complex in specimens.

Roche Diagnostic Systems Inc. have recently developed a commercial PCR (Amplicor) for direct amplification of Mycobacterium tuberculosis Complex (MtbC) from sputum and bronchial washes. Detection of MtbC specific sequence is achieved by hybridization with an oligonucleotide probe. The aim of this study was to compare the Amplicor PCR system for detection of MtbC with microscopy, culture and an in-house PCR method. The commercial assay correctly identified 35/37 microscopy positive specimens compared to 34/37 with the in-house method and 7/13 microscopy negative, culture positive samples compared to 2/13 with the in-house procedure. Negative PCR results were obtained for 32 culture negative specimens and 6 specimens which yielded mycobacteria other than MtbC, indicating a specificity of 100%. The sensitivity of the commercial assay was determined to be approximately 10 organisms compared to 100 organisms with the in-house method. The Amplicor PCR system is specific, sensitive and easy to perform. It also has the advantages of being standardized and quality controlled.

Hepatic lacI and cII mutation in transgenic (lambdaLIZ) rats treated with dimethylnitrosamine.

The recent introduction of a transgenic rat in vivo mutation assay is a much needed supplement to the transgenic mouse models and offers the tools necessary for collecting target tissue specific genotoxicity data in this species. The utility of the Big Blue(R) rat for the detection of in vivo mutations was investigated by studying spontaneous and dimethylnitrosamine (DMN)-induced hepatic mutations. High molecular weight DNA isolated from Big Blue(R) rat livers typically yielded good transgene rescue efficiency of up to 5x105 plaque forming units per packaging reaction. DMN, when administered by oral gavage at dose levels of 0.2, 0.6, 2.0, and 6.0 mg kg-1 day-1, induced up to a 4.5-fold increase in mutations at the highest dose level. There was no apparent difference between the lacI vs. cII target genes of the shuttle vector in either the background or DMN-induced mutant frequencies. These results suggest that the transgenic rat model is a useful tool for studying potential genotoxicity in target organs and, with further validation, the selectable cII target could be an attractive alternative to the conventional lacI color screening method for the detection of mutations in the lambdaLIZ shuttle vector.

The factor structure of the Personality Assessment Inventory-Borderline Features (PAI-BOR) Scale in a nonclinical sample.

We evaluated the fit of Morey's (1991) proposed 4-factor structure on Personality Assessment Inventory-Borderline Features Scale (PAI-BOR; Morey, 1991) items in a sample of approximately 5,000 nonclinical participants. The proposed model did not fit the data well. Results from a series of exploratory and confirmatory factor analyses suggested that a 6-factor model provided the best fit to the PAI-BOR item covariances.

Quantification and variability analysis of bacterial cross-contamination rates in common food service tasks.

This study investigated bacterial transfer rates between hands and other common surfaces involved in food preparation in the kitchen. Nalidixic acid-resistant Enterobacter aerogenes B199A was used as a surrogate microorganism to follow the cross-contamination events. Samples from at least 30 different participants were collected to determine the statistical distribution of each cross-contamination rate and to quantify the natural variability associated with that rate. The transfer rates among hands, foods, and kitchen surfaces were highly variable, being as low as 0.0005% and as high as 100%. A normal distribution was used to describe the variability in the logarithm of the transfer rates. The mean +/- SD of the normal distributions were, in log percent transfer rate, chicken to hand (0.94 +/- 0.68), cutting board to lettuce (0.90 +/- 0.59), spigot to hand (0.36 +/- 0.90), hand to lettuce (-0.12 +/- 1.07), prewashed hand to postwashed hand (i.e., hand washing efficiency) (-0.20 +/- 1.42), and hand to spigot (-0.80 +/- 1.09). Quantifying the cross-contamination risk associated with various steps in the food preparation process can provide a scientific basis for risk management efforts in both home and food service kitchens.

Effect of lymphatic and splenic pump techniques on the antibody response to hepatitis B vaccine: a pilot study.

Osteopathic manipulative treatment (OMT) facilitates the movement of lymphatic fluid and may enhance the immunologic response to infection or injected antigen. In this investigation, two groups of volunteers were vaccinated with recombinant hepatitis B vaccine, given at 0, 5, and 25 weeks. The experimental group (n = 20) received OMT (lymphatic and splenic pump) three times per week for 2 weeks after each vaccination. Control subjects (n = 19) received vaccine but no OMT. Resultant serum antibody levels were measured by enzyme immunoassay. Fifty percent of subjects in the treatment group achieved protective antibody titers (> or = 10 mIU/mL) on the 13th week with an average titer of 374 mIU/mL. Only 16% of the control subjects had positive antibody responses, with average titers of 96 mIU/mL. At all time points from week 6 on, the average anti-hepatitis B titer was higher in the treatment group than in the control group. These data suggest an enhanced immunologic response in subjects who received OMT.