Impaired contractile function of the supraspinatus in the acute period following a rotator cuff tear

Background: Rotator cuff (RTC) tears are a common clinical problem resulting in adverse changes to the muscle, but there is limited information comparing histopathology to contractile function. This study assessed supraspinatus force and susceptibility to injury in the rat model of RTC tear, and compared these functional changes to histopathology of the muscle. Methods: Unilateral RTC tears were induced in male rats via tenotomy of the supraspinatus and infraspinatus. Maximal tetanic force and susceptibility to injury of the supraspinatus muscle were measured in vivo at day 2 and day 15 after tenotomy. Supraspinatus muscles were weighed and harvested for histologic analysis of the neuromuscular junction (NMJ), intramuscular lipid, and collagen. Results: Tenotomy resulted in eventual atrophy and weakness. Despite no loss in muscle mass at day 2 there was a 30% reduction in contractile force, and a decrease in NMJ continuity and size. Reduced force persisted at day 15, a time point when muscle atrophy was evident but NMJ morphology was restored. At day 15, torn muscles had decreased collagen-packing density and were also more susceptible to contraction-induced injury. Conclusion: Muscle size and histopathology are not direct indicators of overall RTC contractile health. Changes in NMJ morphology and collagen organization were associated with changes in contractile function and thus may play a role in response to injury. Although our findings are limited to the acute phase after a RTC tear, the most salient finding is that RTC tenotomy results in increased susceptibility to injury of the supraspinatus

The Secret Life of the Anthrax Agent Bacillus anthracis: Bacteriophage-Mediated Ecological Adaptations

Ecological and genetic factors that govern the occurrence and persistence of anthrax reservoirs in the environment are obscure. A central tenet, based on limited and often conflicting studies, has long held that growing or vegetative forms of Bacillus anthracis survive poorly outside the mammalian host and must sporulate to survive in the environment. Here, we present evidence of a more dynamic lifecycle, whereby interactions with bacterial viruses, or bacteriophages, elicit phenotypic alterations in B. anthracis and the emergence of infected derivatives, or lysogens, with dramatically altered survival capabilities. Using both laboratory and environmental B. anthracis strains, we show that lysogeny can block or promote sporulation depending on the phage, induce exopolysaccharide expression and biofilm formation, and enable the long-term colonization of both an artificial soil environment and the intestinal tract of the invertebrate redworm, Eisenia fetida. All of the B. anthracis lysogens existed in a pseudolysogenic-like state in both the soil and worm gut, shedding phages that could in turn infect non-lysogenic B. anthracis recipients and confer survival phenotypes in those environments. Finally, the mechanism behind several phenotypic changes was found to require phage-encoded bacterial sigma factors and the expression of at least one host-encoded protein predicted to be involved in the colonization of invertebrate intestines. The results here demonstrate that during its environmental phase, bacteriophages provide B. anthracis with alternatives to sporulation that involve the activation of soil-survival and endosymbiotic capabilities

Pulmonary Response to Exercise, Woodsmoke, and Acute Sleep Deprivation

Our laboratory studied the combined effects of smoke exposure, exercise, and sleep deprivation to better understand the causes of the long-term deleterious health effects of woodsmoke in at risk populations, such as wildland firefighters. The purpose of this paper is to report on the results of our pulmonary function tests (PFT). Ten recreationally active male participants (age = 24±4 yrs.; height = 185.2±3.9 cm; weight = 85.7±9.4 kg; VO2max = 46.8.7±.7 ml∙min¯¹∙kg¯¹; body fat = 12.6±6.7 %) performed two separate 45-minute stationary bicycle workouts (70% VO2max) while exposed to woodsmoke particulate matter \u3c2.5um (PM2.5) at a concentration of 250μg/m3. One trial was performed on 8 hours of sleep and the other on 4 hours of sleep. Duplicate pulmonary data for key dependent measures of PFT (FVC, FEV1%, MVV) taken before and after each workout showed no statistically significant differences between trials or across trials when examined by a two-way ANOVA analysis (FVC time p = 0.949, trial p=0.919, time-trial p=0.837; FEV1 time p=0.684, trial p=0.769, time-trial p=0.857; FEV1% time p=0.540, trial p=0.712, time-trial p=0.986; MVV time p=0.917, trial p=0.633, time-trial p=0.923). These results are consistent with the literature from participants with normal sleep patterns.1 No alterations in acute measures of pulmonary function were observed in apparently healthy individuals exposed to PM2.5 250μg/m3 of woodsmoke during exercise, nor does acute sleep deprivation alter these results

Estudo histológico e computadorizado das áreas com células parietais e principais no estômago de ratos Wistar tratados com pantoprazol e "N-Nitroso-N-Methylurea"(NMU) Histological and computer-assisted analysis of parietal and chief cells stomach areas in Wistar rats treated with pantoprazole and N-Nitroso-N-Methylurea (NMU)

O uso prolongado dos inibidores da bomba de prótons tem sido considerado uma condição de risco para o desenvolvimento de gastrite atrófica e tumores gástricos. Objetivo: Estudar o efeito do uso de pantoprazol (PTZ) e carcinogênese pela "N-Nitroso-N-Methylurea" (NMU), por 15 semanas, sobre o estômago glandular de ratos Wistar, pela análise histológica e computadorizada das áreas com células parietais (AP), principais (AZ) e da mucosa não oxíntica (ANO), além do estudo das alterações histopatológicas identificadas. Métodos: Quarenta ratos Wistar machos foram distribuídos em 4 grupos: G1 (controle), G2 (NMU+PTZ), G3 (PTZ) e G4 (NMU). O pantoprazol foi administrado 2x/semana (14mg/kg de peso, i.p.) e a NMU oferecida, ad libitum, diluída na água de beber (100mig/ml). Após o estudo histológico AP, AZ e ANO foram determinadas por análise computadorizada das imagens dos estômagos, utilizando o programa "ImageJ 1.19z". Resultados: Mostraram redução da AP e aumento da ANO, em G2, G3 e G4 (p<0,001). Foram encontrados casos de atrofia, inflamação aguda e inflamação crônica, em número que impediu comparação estatística entre os grupos estudados. Conclusão: O uso contínuo de pantoprazol (i.p.), por 15 semanas, reduziu a área com células parietais e aumentou a área de mucosa não oxíntica no estômago glandular de ratos Wistar machos. O mesmo aconteceu no grupo de animais que receberam NMU isoladamente ou em associação com o pantoprazol.<br>The long-term use of proton bomb inhibitors has been considered a risk condition for the development of atrophic gastritis and gastric tumors. Objective: The aim of this study was to investigate the effects of pantoprazole (PTZ) treatment and N-Nitroso-N-Methylurea (NMU) carcinogenesis, for 15 weeks, in the glandular stomach of rats by histological and computer-assisted analysis of parietal cells area (PA), chief cells area (CP) and non-oxintic mucosal area (ANO), as well as by histopathological study. Methods: A total of 40 male Wistar rats were divided into four groups on the basis of the treatment: G1 (control), G2 (NMU+PTZ), G3 (PTZ) and G4 (NMU). Pantoprazole was administered twice a week (14mg/kg body wt., i.p.) and NMU was given in the drinking water (100ppm) ad libitum. After histological examination AP, AZ and ANO were investigated by computer-assisted analysis of the stomach image using the program ImageJ1.19z. Results: Showed a reduction of AP and increase of ANO in G2, G3 and G4 (p<0,001). Cases of atrophy, acute and chronic inflammation were found in number that impeded statistical comparison among the studied groups. Conclusion: The continuous administration, for 15 weeks, of pantoprazole (14mg/kg body wt., i.p.) and NMU (100ppm in the drinking water, ad libitum), isolated or associated, determines a reduction of parietal cells area and increase of non-oxintic mucosal area in glandular stomach of male Wistar rats