MiniBioReactor Array (MBRA) in vitro gut model: a reliable system to study microbiota-dependent response to antibiotic treatment.

Background: Antimicrobial drugs are mostly studied for their impact on emergence of bacterial antibiotic resistance, but their impact on the gut microbiota is also of tremendous interest. In vitro gut models are important tools to study such complex drug-microbiota interactions in humans. Methods: The MiniBioReactor Array (MBRA) in vitro microbiota system; a single-stage continuous flow culture model, hosted in an anaerobic chamber; was used to evaluate the impact of three concentrations of a third-generation cephalosporin (ceftriaxone) on faecal microbiota from two healthy donors (treatment versus control: three replicates per condition). We conducted 16S microbiome profiling and analysed microbial richness, diversity and taxonomic changes. ß-Lactamase activities were evaluated and correlated with the effects observed in the MBRA in vitro system. Results: The MBRA preserved each donor's specificities, and differences between the donors were maintained through time. Before treatment, all faecal cultures belonging to the same donor were comparable in composition, richness, and diversity. Treatment with ceftriaxone was associated with a decrease in α-diversity, and an increase in ß-diversity index, in a concentration-dependent manner. The maximum effect on diversity was observed after 72 h of treatment. Importantly, one donor had a stronger microbiota ß-lactamase activity that was associated with a reduced impact of ceftriaxone on microbiota composition. Conclusions: MBRA can reliably mimic the intestinal microbiota and its modifications under antibiotic selective pressure. The impact of the treatment was donor- and concentration-dependent. We hypothesize these results could be explained, at least in part, by the differences in ß-lactamase activity of the microbiota itself. Our results support the relevance and promise of the MBRA system to study drug-microbiota interactions.

Climate change mitigation in Canada's forest sector: a spatially explicit case study for two regions.

BACKGROUND: We determine the potential of forests and the forest sector to mitigate greenhouse gas (GHG) emissions by changes in management practices and wood use for two regions within Canada's managed forest from 2018 to 2050. Our modeling frameworks include the Carbon Budget Model of the Canadian Forest Sector, a framework for harvested wood products that estimates emissions based on product half-life decay times, and an account of marginal emission substitution benefits from the changes in use of wood products and bioenergy. Using a spatially explicit forest inventory with 16 ha pixels, we examine mitigation scenarios relating to forest management and wood use: increased harvesting efficiency; residue management for bioenergy; reduced harvest; reduced slashburning, and more longer-lived wood products. The primary reason for the spatially explicit approach at this coarse resolution was to estimate transportation distances associated with delivering harvest residues for heat and/or electricity production for local communities. RESULTS: Results demonstrated large differences among alternative scenarios, and from alternative assumptions about substitution benefits for fossil fuel-based energy and products which changed scenario rankings. Combining forest management activities with a wood-use scenario that generated more longer-lived products had the highest mitigation potential. CONCLUSIONS: The use of harvest residues to meet local energy demands in place of burning fossil fuels was found to be an effective scenario to reduce GHG emissions, along with scenarios that increased the utilization level for harvest, and increased the longevity of wood products. Substitution benefits from avoiding fossil fuels or emissions-intensive products were dependent on local circumstances for energy demand and fuel mix, and the assumed wood use for products. As projected future demand for biomass use in national GHG mitigation strategies could exceed sustainable biomass supply, analyses such as this can help identify biomass sources that achieve the greatest mitigation benefits.

Gas chromatography-mass spectrometry-Fourier transform infrared spectrometry and high-performance liquid chromatographic characterization of mononitro- and dinitro-isomers from the nitration of N,N-dimethyldiphenylacetamide.

Gas chromatographic retention data, Fourier transform infrared and mass spectrometric (electron impact, electron attachment and methane chemical ionization) profiles are reported for the products of mono- and dinitration of N,N-dimethyldiphenylacetamide. Differentiations of analytical importance among isomers could be gathered by the study which led to their complete identification.

Individual characteristics and quitting in apprentices exposed to high-molecular-weight agents.

To determine whether specific immunological sensitization (SIS) and symptoms of allergy are associated with quitting apprenticeships with exposure to high-molecular-weight (HMW) agents. In a cohort study of 769 apprentices starting career programs in animal health technology (AHT), pastry-making (PM), and dental hygiene technology (DHT), health status was assessed at baseline and yearly for up to 44 mo. Subjects who quit the apprenticeship were contacted and offered a last series of measurements as if they pursued. The effect of various factors-at baseline and during the career program-on quitting was examined. Eighty-nine of 769 subjects (11.6%) quit, of whom 74 participated in this study. In multivariate analysis, a history of hay fever (OR = 1.66, 95% CI = 1.0 to 2.75) and attending the pastry-making program (OR = 2.33, 95% CI = 1.11 to 4.91) were significant determinants for quitting. In the subgroup of AHT, SIS to laboratory animals, hay fever, and shortness of breath were significant determinants by univariate analysis; in PM, the only determinant was age; and in DHT, hay fever. Work-related symptoms during training were not associated with quitting. In a multivariate logistic regression analysis in AHT, including characteristics at baseline and at follow-up, baseline SIS (OR = 2.8, 95% CI = 0.94 to 8.38) and symptoms of asthma in general during follow-up (OR = 2.2, 95% CI = 0.94 to 5.38) were the main determinants for quitting, though they were of borderline significance. We conclude that health-related self-selection out of an apprenticeship with exposure to HMW agents is likely to occur and to cause an attrition bias.

Stereoselective synthesis of non symmetric dihydroxyethylene dipeptide isosteres via epoxy alcohols derived from alpha-amino acids.

(1R,2R,3S,4S)-4-Amino-3-hydroxy-1,2-epoxybutanes, accessible in four steps from L-aminoesters, react regio- and stereoselectively with diethyl aluminum cyanide to give (1R,2S,3S,4S)-4-amino-2,3-dihydroxynitriles. Hydrolysis yields hydroxylactones equivalent to 2,3-dihydroxy-4-aminoacids. The sequence provides a novel approach to dihydroxyethylene isosteres potentially useful for new HIV-protease inhibitors.

FIV induced encephalopathy: early brain lesions in the absence of viral replication in monocyte/macrophages. A pathogenetic model.

FIV induced encephalopathy represents a model for the study of the neuropathogenesis of AIDS. It has yet to be determined whether massive viral replication is a prerequisite for the development of early brain lesions. Using a drug delivery system developed by us, we have shown that early encephalic lesions appear in FIV infected subjects even when viral transport within the brain has been markedly reduced or blocked.

Psychological considerations for patients with acute wounds.

The range of psychological considerations for patients with acute wounds is very great, to an extent that makes any generalization extremely difficult. Adverse psychological developments seem to occur most often when there are permanent changes in the body's structure or function. Reactions may be particularly troublesome if the wound occurs as a result of trauma, involves an emotionally loaded body part or function, or results in visible deformity. Critical care nurses can help patients begin the process of reintegrating the body image by providing congruent verbal and behavioral messages that communicate to the patient that his or her worth and value as a human being has not been lost.

Risk factors associated with having a pressure ulcer: a secondary data analysis.

Data obtained through five hospital-wide pressure ulcer audits were pooled for exploratory analysis. The purpose of this secondary data analysis was (1) to delineate the association of various risk factors and the presence of pressure ulcers and (2) to generate specific, testable hypotheses. Risk factors studied included fecal incontinence, urinary incontinence, malnutrition, impaired mobility, decreased mental status, diabetes mellitus, peripheral vascular disease, spinal cord injury, multiple sclerosis, and metastatic carcinoma. Stepwise logistic regression resulted in a best-fitting model that included fecal incontinence, impaired mobility, malnutrition, decreased mental status, and an interaction effect between fecal incontinence and impaired mobility. This model suggested that the odds of having a pressure ulcer were 22 times greater for hospitalized adult patients with fecal incontinence compared to hospitalized adult patients without fecal incontinence.

Approaches to patient and family education for pressure ulcer management.

The Agency for Health Care Policy and Research (AHCPR) guidelines for pain management, urinary incontinence, and pressure ulcers emphasize the importance of patient and family education. Patient teaching strategies are discussed by using the example of pressure ulcer management. The family is invited into an educational partnership through needs assessment and mutual goal setting. Teaching strategies that involve the learner and are adapted for the home setting are most effective. Evaluation of teaching should be in terms of patient outcomes.

[Patients treated for one year with tianeptine. Results at one of the centers of South-Eastern France]. / Patients traités un an par la tianeptine. Présentation des résultats obtenus par l'un des Centres du Sud-Est de la France.

Tianeptine is a new antidepressant with a tricyclic molecular structure. Its main neurochemical effect consists in an increase in serotonine re-uptake. Its efficacy as antidepressant and its good clinical safety have been confirmed in controlled trials against reference drugs. 1,231 patients with a DSM III diagnosis of major depression or dysthymic disorder were included in a long-term trial with tianeptine. 510 patients completed the one-year treatment period. The results of a subgroup of 100 patients treated in one of the centres of south-east France will be presented. 47 of these patients completed the trial. This study allowed to evaluate the therapeutic efficacy as well as the clinical safety of tianeptine during long-term prescription. Patients were treated in an open design after a 4-7 day placebo washout period. Therapeutic effects were assessed by the C.G.I. items (1 and 2), MADRS, HARS and HSCL. For the evaluation of clinical and paraclinical safety, spontaneous complaints of the patients and CGI-3 were documented; body weight, blood pressure and blood chemistry were also measured. Homogeneity between completers and non-completers was tested before statistical analysis of the clinical effects. Results of completers were analyzed using a two-way ANOVA (time x subjects); Newman-Keuls tests were performed in the case of a significant time effect. End-point analysis was used to test the results of the total sample. Patients completing the trial had a mean MADRS baseline score of 32.8. Given high this score, the patients have to be considered genuinely depressed at inclusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of a new endoglucanase from Erwinia chrysanthemi.

The structural gene coding for a new endo-beta-1,4-glucanase of Erwinia chrysanthemi strain 3665, previously identified in a cosmid library, was subcloned into pUC18. The gene is expressed from a 1.9 X 10(3)-base-pair insert and its direction of transcription was determined. The properties of the gene product purified from cell-free extracts of Escherichia coli have been studied. The purified protein has an endoglucanase activity but is significantly different from the major endoglucanase Z secreted by E. chrysanthemi strain 3665. The new enzyme was designated as endoglucanase Y and the related gene celY. In E. coli, most of the endoglucanase activity was found in the periplasmic space.