A retrospective study of judicial encounters of young adults with congenital heart disease.

Young people with congenital heart disease are often marginalised and may compensate for restricted physical and social abilities by substance abuse or risk-taking behaviour. We report on the judicial encounters of patients in an Adult Congenital Heart unit. Fifteen patients had court appearances and all were male. Seven served jail sentences, including four indigenous adolescents. All had multiple interventions for their cardiac conditions and four are now deceased. The majority of patients had mental health issues and substance misuse. These patients need psychological and medical support, and help with judicial authorities. Recommendations for ongoing care are provided.

Interactions of Salmonella enterica subspecies enterica serovar Typhimurium with gut bacteria.

The aim of this study was to evaluate the impact of the gut microbiota on the growth and survival of S. Typhimurium. This was tested in two-species co-cultures and in mixed cultures with a simplified gut model microbiota. Subsequently, interactions between S. Typhimurium and human faecal bacteria were quantified in both batch and continuous culture systems simulating the human colon. The exponential growth of S. Typhimurium was halted when the population of Escherichia coli reached the maximum population density in a two-compartment co-culture system where the two species were separated by a 0.45 µm pore membrane. Furthermore, the growth of some gut bacteria such as Lactobacillus gasseri and Bifidobacterium bifidum was inhibited by the presence of S. Typhimurium in the other compartment. The survival of S. Typhimurium was severely affected in mixed batch cultures with human faecal samples; a reduction of 10(3)-10(4) cfu/ml in the concentration of S. Typhimurium was observed in these cultures. However, no effect on S. Typhimurium survival was observed in mixed batch cultures with a simplified gut model microbiota under the same conditions. The effect of human faecal samples on S. Typhimurium in a three-stage continuous culture was different to that obtained in batch cultures; its growth rather than survival was affected under these conditions. S. Typhimurium growth was inhibited, and the bacterium was therefore eliminated by the continuous flow of the medium. Depending upon culturing conditions, the gut microbiota caused either growth inhibition, inactivation or did not affect S. Typhimurium.

The effect of betacyclodextrin and hydroxypropyl betacyclodextrin incorporation into plasticized poly(vinyl chloride) on its compatibility with human U937 cells.

Di (2-ethyl hexyl) phthalate (DEHP) is one of the main plasticizers used in poly(vinyl chloride) (PVC) medical devices and is currently the only one listed for use in the European Pharmacopoeia Monograph. It leaches out of PVC when the material is in contact with lipophilic media, for example, blood and certain nutritional feeds. Consequently, concerns have been expressed since in certain animal species, DEHP has been shown to exhibit both carcinogenic and reproductive toxic effects. Incorporation of beta cyclodextrin (BCD) and hydroxypropyl betacyclodectrin (HPBCD) into plasticized materials has been reported to decrease the leaching of DEHP. We have investigated whether this results in improved in vitro biocompatibility by measuring the responses of U937 cells to plasticized PVC in the presence and absence of added BCD or HPBCD. Growth and viability of the U937 cells, as well as tumor necrosis factor-α (TNF-α) production in contact with these materials revealed no significant difference between unmodified plasticized PVC materials and those containing BCD or HPBCD. Lipopolysaccharide (LPS) was used to elicit TNF-α production, and the response of cells to LPS in the presence of the PVC materials was evaluated. When PVC was modified by addition of HPBCD there was a significant reduction in the TNF-α production in response to LPS. Modification of plasticized PVC biomaterials by adding cyclodextrins did not significantly improve their biocompatibility. However, the HPBCD modified plasticized PVC materials caused a reduction in the production in TNF-α induced by LPS which may have implications for the inflammatory potential of these biomaterials.

Parameter estimation for the distribution of single cell lag times.

In Quantitative Microbial Risk Assessment, it is vital to understand how lag times of individual cells are distributed over a bacterial population. Such identified distributions can be used to predict the time by which, in a growth-supporting environment, a few pathogenic cells can multiply to a poisoning concentration level. We model the lag time of a single cell, inoculated into a new environment, by the delay of the growth function characterizing the generated subpopulation. We introduce an easy-to-implement procedure, based on the method of moments, to estimate the parameters of the distribution of single cell lag times. The advantage of the method is especially apparent for cases where the initial number of cells is small and random, and the culture is detectable only in the exponential growth phase.

Physiological state of single cells of Listeria innocua in organic acids.

The growth of Listeria innocua in three organic acids was monitored by optical density measurements in a Bioscreen C automatic plate reader (Labsystems, Finland). The method described by Metris et al. [Metris, A., George, S.M., Baranyi, J., 2006. Use of optical density detection times to assess the effect of acetic acid on single-cell kinetics. Applied and Environmental Microbiology 72, 6674-6679.], was used to estimate both the growth rate and the lag time of single cells. It was found that the logarithm of both the growth rates and the population lag times increased linearly with sorbic acid concentration in the same way as previously described with acetic acid but the relationship was not linear with lactic acid. Of the three acids tested, sorbic was the most inhibitory for an equivalent undissociated acid concentration. The effect of lactic acid was dependent on both the growth phase of the inoculum and the inoculum concentration.

Heterogeneity of times required for germination and outgrowth from single spores of nonproteolytic Clostridium botulinum.

Knowledge of the distribution of growth times from individual spores and quantification of this biovariability are important if predictions of growth in food are to be improved, particularly when, as for Clostridium botulinum, growth is likely to initiate from low numbers of spores. In this study we made a novel attempt to determine the distributions of times associated with the various stages of germination and subsequent growth from spores and the relationships between these stages. The time to germination (t(germ)), time to emergence (t(emerg)), and times to reach the lengths of one (t(C1)) and two (t(C2)) mature cells were quantified for individual spores of nonproteolytic C. botulinum Eklund 17B using phase-contrast microscopy and image analysis. The times to detection for wells inoculated with individual spores were recorded using a Bioscreen C automated turbidity reader and were compatible with the data obtained microscopically. The distributions of times to events during germination and subsequent growth showed considerable variability, and all stages contributed to the overall variability in the lag time. The times for germination (t(germ)), emergence (t(emerg) - t(germ)), cell maturation (t(C1) - t(emerg)), and doubling (t(C2) - t(C1)) were not found to be correlated. Consequently, it was not possible to predict the total duration of the lag phase from information for just one of the stages, such as germination. As the variability in postgermination stages is relatively large, the first spore to germinate will not necessarily be the first spore to produce actively dividing cells and start neurotoxin production. This information can make a substantial contribution to improved predictive modeling and better quantitative microbiological risk assessment.

Distribution of turbidity detection times produced by single cell-generated bacterial populations.

The distributions of the times to turbidity for wells inoculated with single cells of Listeria innocua were determined in different environmental conditions (pH 4.5 to 7 and with 0.5% to 8% of NaCl at 30 degrees C). It was established by statistical analysis that the main source of the variability of the detection times, T, is the variability of individual lag times. A linear relation dev(T) approximately T was observed between the detection times and their standard deviation. At slow growth, other sources of variability became increasingly significant.