Specificity enhancement of polyclonal antisera by the induction of tolerance to unwanted cross-reacting determinants

Steroids form a structurally closely related group. As a result, antibodies produced for use in immunoassays regularly show unwanted cross-reactivities, These may be reduced by altering hapten-protein coupling procedures, thereby reducing the exposure of the determinants giving rise to the undesirable cross-reaction. However, these procedures carl prove to be complex, expensive and nor totally predictable in outcome. Exploitation of the clonal selection theory is an attractive alternative approach. The host is primed with the interfering cross-reactant coupled to a non-immunogenic amino acid copolymer to inactivate the B-lymphocyte clones specific for this steroid, producing a specific immunotolerance. Then, 3 days Inter, the host is immunized with the steroid against which nn antibody is required. The clones producing antibody to this immunogen are unaffected and the cross-reactivity is significantly reduced or deleted The technique has been applied to the reduction of endogenous sex steroid cross-reactivity from antibodies prepared against synthetic and semi-synthetic androgens (17 alpha-methyltestosterone, 19-nor-beta-testosterone) and the progestogen medroxyprogesterone. Antibodies prepared against the synthetic oestrogen zeranol using this technique have significantly reduced its undesirable cross-reactivity with the fungal metabolite 7 alpha-zearalenol. Highly specific antisera have been generated in all cases, the only adverse effect being a reduction in the titres achieved in comparison with rabbits receiving the conventional immunizing regime.

Fetal brain function in response to maternal alcohol consumption: Early evidence of damage

Background: Studies of the adverse neurobehavioral effects of maternal alcohol consumption on the fetus have been largely confined to the postnatal period, after exposure to alcohol has finished. This study explored the brain function of the fetus, at the time of exposure to alcohol, to examine its effect on information processing and stability of performance. Methods: Five groups of fetuses, defined by maternal alcohol consumption patterns, were examined: control (no alcohol); moderate (5 to 10 units/wk either drunk evenly across the week or as a binge, in 2 to 3 days); heavy (20+ units/wk drunk evenly or as a binge). Fetal habituation performance was examined on 3 occasions, separated by 7 days, beginning at 35 weeks of gestation. The number of trials required to habituate on each test session and the difference in performance across test sessions were recorded. Results: Fetuses exposed to heavy binge drinking required significantly more trials to habituate and exhibited a greater variability in performance across all test sessions than the other groups. Maternal drinking, either heavily but evenly or moderately as a binge, resulted in poorer habituation, and moderate binge drinking resulted in greater variability compared with no, or even, drinking. Conclusions: Decreased information processing, reflected by poorer habituation, and increased variability in performance may reflect the initial manifestations of structural damage caused by alcohol to the brain. These results will lead to a greater understanding of the effects of alcohol on the fetus's brain, enable the antenatal identification of fetal alcohol spectrum disorders, and lead to the early implementation of better management strategies. © 2012 by the Research Society on Alcoholism.


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Intravenous tolerance effectively overcomes enhanced pro-inflammatory responses and EAE severity in the absence of IL-12 receptor signaling

Intravenous (i.v.) administration of autoantigen effectively induces Ag-specific tolerance against experimental autoimmune encephalomyelitis (EAE). We and others have shown enhanced EAE severity in mice lacking IL-12 or its receptor, strongly suggesting an immunoregulatory effect of IL-12 signaling. To examine the role of IL-12 responsiveness in autoantigen-induced tolerance in EAE, we administered autoantigen i.v. in two distinct treatment regimes to wildtype and IL-12Rβ2(-/-) mice, immunized to develop EAE. Administration at the induction phase suppressed EAE in wildtype and IL-12Rβ2(-/-) mice however the effect was somewhat less potent in the absence of IL-12Rβ2. Expression of pro-inflammatory cytokines such as IFN-γ, IL-17 and IL-2, was inhibited in wild-type tolerized mice but less so in IL-12Rβ2(-/-) mice. I.v. antigen was also effective in suppressing disease in both genotypes when given during the clinical phase of disease with similar CNS inflammation, demyelination and peripheral inflammatory cytokine profiles observed in both genotypes. There was however a mild impact of a lack of IL-12 signaling on Treg induction during tolerance induction compared to WT mice in this treatment regime. These findings show that the enhanced severity of EAE that occurs in the absence of IL-12 signaling can be effectively overcome by i.v. autoantigen, indicating that this therapeutic effect is not primarily mediated by IL-12 and that i.v. tolerance could be a powerful approach in suppressing severe and aggressive MS.

Hopanoid Production Is Required for Low-pH Tolerance, Antimicrobial Resistance, and Motility in Burkholderia cenocepacia

Hopanoids are pentacyclic triterpenoids that are thought to be bacterial surrogates for eukaryotic sterols, such as cholesterol, acting to stabilize membranes and to regulate their fluidity and permeability. To date, very few studies have evaluated the role of hopanoids in bacterial physiology. The synthesis of hopanoids depends on the enzyme squalene-hopene cyclase (Shc), which converts the linear squalene into the basic hopene structure. Deletion of the 2 genes encoding Shc enzymes in Burkholderia cenocepacia K56-2, BCAM2831 and BCAS0167, resulted in a strain that was unable to produce hopanoids, as demonstrated by gas chromatography and mass spectrometry. Complementation of the Delta shc mutant with only BCAM2831 was sufficient to restore hopanoid production to wild-type levels, while introducing a copy of BCAS0167 alone into the Delta shc mutant produced only very small amounts of the hopanoid peak. The Delta shc mutant grew as well as the wild type in medium buffered to pH 7 and demonstrated no defect in its ability to survive and replicate within macrophages, despite transmission electron microscopy (TEM) revealing defects in the organization of the cell envelope. The Delta shc mutant displayed increased sensitivity to low pH, detergent, and various antibiotics, including polymyxin B and erythromycin. Loss of hopanoid production also resulted in severe defects in both swimming and swarming motility. This suggests that hopanoid production plays an important role in the physiology of B. cenocepacia.

Job Strain and Alcohol Intake:A Collaborative Meta-Analysis of Individual-Participant Data from 140 000 Men and Women

BACKGROUND: The relationship between work-related stress and alcohol intake is uncertain. In order to add to the thus far inconsistent evidence from relatively small studies, we conducted individual-participant meta-analyses of the association between work-related stress (operationalised as self-reported job strain) and alcohol intake. METHODOLOGY AND PRINCIPAL FINDINGS: We analysed cross-sectional data from 12 European studies (n?=?142 140) and longitudinal data from four studies (n?=?48 646). Job strain and alcohol intake were self-reported. Job strain was analysed as a binary variable (strain vs. no strain). Alcohol intake was harmonised into the following categories: none, moderate (women: 1-14, men: 1-21 drinks/week), intermediate (women: 15-20, men: 22-27 drinks/week) and heavy (women: >20, men: >27 drinks/week). Cross-sectional associations were modelled using logistic regression and the results pooled in random effects meta-analyses. Longitudinal associations were examined using mixed effects logistic and modified Poisson regression. Compared to moderate drinkers, non-drinkers and (random effects odds ratio (OR): 1.10, 95% CI: 1.05, 1.14) and heavy drinkers (OR: 1.12, 95% CI: 1.00, 1.26) had higher odds of job strain. Intermediate drinkers, on the other hand, had lower odds of job strain (OR: 0.92, 95% CI: 0.86, 0.99). We found no clear evidence for longitudinal associations between job strain and alcohol intake. CONCLUSIONS: Our findings suggest that compared to moderate drinkers, non-drinkers and heavy drinkers are more likely and intermediate drinkers less likely to report work-related stress.

Simultaneous use of mephedrone and alcohol: A qualitative study of users' experiences

Mephedrone (4-methylmethcathinone) gained popularity across "recreational" drug scenes in the United Kingdom and Ireland during 2009. Although mephedrone was banned in both jurisdictions in 2010, the drug was subsequently sourced through street dealers. This qualitative study explores the simultaneous use of mephedrone and alcohol, among study participants who used mephedrone following legislative controls. Data were collected through semi-structured interviews with male and female respondents. The results suggest a three-tier classification system that describes users' experiences with simultaneous use of mephedrone and alcohol. Most participants engaged in "heavy" alcohol use immediately prior to consuming mephedrone, and then reduced alcohol consumption as the effects of mephedrone were experienced during the drug episode. Spontaneous use of mephedrone often was associated with larger amounts of alcohol being consumed just prior to the mephedrone episode. The findings have the potential for informing socioepidemiological surveys as well as peer interventions to reduce harm associated with
simultaneous drug use.