Phenotypic and genetic characterization of a novel phenotype in pigs characterized by juvenile hairlessness and age dependent emphysema

<p>Abstract</p> <p>Background</p> <p>A pig phenotype characterized by juvenile hairlessness, thin skin and age dependent lung emphysema has been discovered in a Danish pig herd. The trait shows autosomal co-dominant inheritance with all three genotypes distinguishable. Since the phenotype shows resemblance to the integrin β₆-/- knockout phenotype seen in mice, the two genes encoding the two subunits of integrin α_vβ₆, i.e. <it>ITGB6 </it>and <it>ITGAV</it>, were considered candidate genes for this trait.</p> <p>Results</p> <p>The mutated pig phenotype is characterized by hairlessness until puberty, thin skin with few hair follicles and absence of <it>musculi arrectores pili</it>, and at puberty or later localized areas of emphysema are seen in the lungs. Comparative mapping predicted that the porcine <it>ITGB6 </it>and<it>ITGAV </it>orthologs map to SSC15. In an experimental family (n = 113), showing segregation of the trait, the candidate region was confirmed by linkage analysis with four microsatellite markers. Mapping of the porcine <it>ITGB6 </it>and <it>ITGAV </it>in the IMpRH radiation hybrid panel confirmed the comparative mapping information. Sequencing of the <it>ITGB6 </it>and <it>ITGAV </it>coding sequences from affected and normal pigs revealed no evidence of a causative mutation, but alternative splicing of the <it>ITGB6 </it>pre-mRNA was detected. For both <it>ITGB6 </it>and <it>ITGAV </it>quantitative PCR revealed no significant difference in the expression levels in normal and affected animals. In a western blot, ITGB6 was detected in lung protein samples of all three genotypes. This result was supported by flow cytometric analyses which showed comparable reactions of kidney cells from affected and normal pigs with an integrin α_vβ₆monoclonal antibody. Also, immunohistochemical staining of lung tissue with an integrin β₆antibody showed immunoreaction in both normal and affected pigs.</p> <p>Conclusion</p> <p>A phenotype resembling the integrin β₆-/- knockout phenotype seen in mice has been characterized in the pig. The candidate region on SSC15 has been confirmed by linkage analysis but molecular and functional analyses have excluded that the mutated phenotype is caused by structural mutations in or ablation of any of the two candidate genes.</p

Dynamics of a Staphylococcus aureus infective endocarditis simulation model

Infective endocarditis (IE) is a serious infection of the inner surface of heart, resulting from minor lesions in the endocardium. The damage induces a healing reaction, which leads to recruitment of fibrin and immune cells. This sterile healing vegetation can be colonized during temporary bacteremia, inducing IE. We have previously established a novel in vitro IE model using a simulated IE vegetation (IEV) model produced from whole venous blood, on which we achieved stable bacterial colonization after 24h. The bacteria were organized in biofilm aggregates and displayed increased tolerance towards antibiotics. In this current study, we aimed at further characterizing the time course of biofilm formation and the impact on antibiotic tolerance development. We found that a S. aureus reference strain, as well as three clinical IE isolates formed biofilms on the IEV after 6h. When treatment was initiated immediately after infection, the antibiotic effect was significantly higher than when treatment was started after the biofilm was allowed to mature. We could follow the biofilm development microscopically by visualizing growing bacterial aggregates on the IEV. The findings indicate that mature, antibiotic-tolerant biofilms can be formed in our model already after 6h, accelerating the screening for optimal treatment strategies for IE

Injection site microflora in persons with diabetes:why needle reuse is not associated with increased infections?

Needle reuse is a common practice and primary cause of customer compliance issues such as pain, bruising, clogging, injection site reactions (ISR), and associated lipodystrophy. This study aimed to characterize skin microflora at injection sites and establish microbial contamination of used pen injectors and needles. The second objective was to evaluate the risk of infections during typical and repeated subcutaneous injections. 50 participants with diabetes and 50 controls (n = 100) were sampled through tape strips and skin swabs on the abdomen and thigh for skin microflora. Used pen injectors and needles were collected after in‐home use and from the hospital after drug administration by health care professionals (HCPs). Samples were analyzed by conventional culture, matrix‐assisted laser desorption/ionization‐time of flight (MALDI‐TOF), mass spectrometry (MS), confocal laser scanning microscopy (CLSM), and 16S/ITS high throughput sequencing (HTS). A mathematical model simulated the risk of needle contamination during injections. Injection site populations were in 10(2) cells/cm(2) order, with increased viable bacteria and anaerobic bacteria on the skin in persons with diabetes (p = 0.05). Interpersonal variation dominated other factors such as sex or location. A higher prevalence of Staphylococcus aureus on abdominal skin was found in persons with diabetes than control skin (p ≤ 0.05). Most needles and cartridges (95% and 86%) contained no biological signal. The location of the device collection (hospital vs home‐use) and use regimen did not affect contamination. CLSM revealed scarcely populated skin microflora scattered in aggregates, diplo, or single cells. Our mathematical model demonstrated that penetrating bacteria colonies during subcutaneous injection is unlikely. These findings clarify the lack of documented skin infections from subcutaneous insulin injections in research. Furthermore, these results can motivate the innovation and development of durable, reusable injection systems with pharmacoeconomic value and a simplified and enhanced user experience for patients