Ischemia and reperfusion of the soleus muscle of rats with pentoxifylline

BACKGROUND: Reperfusion of the skeletal muscle worsens existing lesions during ischemia, since the production of reactive oxygen species, associated with intense participation of neutrophils, increases the inflammatory reaction that induces tissue changes. OBJECTIVE: To evaluate the morphological and immunohistochemical changes of the skeletal (soleus) muscle of rats submitted to ischemia and reperfusion with pentoxifylline. METHODS: Sixty rats were submitted to ischemia of the pelvic limb for 6 hours induced by clamping the left common iliac artery. After ischemia, group A animals (n = 30) were observed for 4 hours and group B animals (n = 30) for 24 hours. Six animals constituted the sham group. Pentoxifylline was applied only in the reperfusion period A2 (n = 10) and B2 (n = 10), and in ischemia and reperfusion periods in A3 (n = 10) and B3 (n = 10). The soleus muscle was evaluated by histological (fiber disruption, leukocyte infiltrate, necrosis) and immunohistochemical (apoptosis through caspase-3 expression) analysis. The non-parametric tests Kruskal-Wallis and Mann-Whitney (p < 0.05) were applied. RESULTS: The changes were more intense in group B1, with fiber disruption mean scores of 2.16±0.14; neutrophilic infiltrate of 2.05±0.10; and caspase-3 expression in the perivascular area of 4.30±0.79; and less intense in group A3, with means of 0.76±0.16; 0.92±0.10; 0.67±0,15, respectively (p < 0.05). Caspase-3 was more expressive in group B1 in the perivascular area, with mean of 4.30±0.79 when compared with group B1 in the perinuclear area, with mean of 0.91±0.32 (p < 0.05) CONCLUSIONS: The lesions were more intense when observation time was longer after reperfusion, and pentoxifylline attenuated these lesions, above all when used in the beginning of ischemia and reperfusion phases.CONTEXTO: A reperfusão de músculo esquelético piora as lesões já presentes no período de isquemia, pois a produção de espécies reativas de oxigênio, associadas à intensa participação de neutrófilos, amplia a reação inflamatória que induz alterações teciduais. OBJETIVO: Avaliar as alterações morfológicas e imuno-histoquímicas de músculo esquelético (sóleo) de ratos submetidos a isquemia e reperfusão com pentoxifilina. MÉTODOS: Sessenta ratos foram submetidos a isquemia do membro pélvico, por 6 horas, pelo clampeamento da artéria ilíaca comum esquerda. Após isquemia, os animais do grupo A (n = 30) foram observados por 4 horas, e os do grupo B (n = 30), por 24 horas. Seis animais constituíram o grupo simulado. Administrou-se pentoxifilina apenas no período de reperfusão em A2 (n = 10) e B2 (n = 10) e nos períodos de isquemia e reperfusão em A3 (n = 10) e B3 (n = 10). O músculo sóleo foi avaliado por análise histológica (dissociação de fibras, infiltrado leucocitário, necrose) e imuno-histoquímica (apoptose pela expressão da caspase-3). Foram aplicados os testes não-paramétricos de Kruskal-Wallis e Mann-Whitney (p < 0,05). RESULTADOS: As alterações foram mais intensas no grupo B1, com médias de escore da dissociação de fibras musculares de 2,16 ± 0,14, infiltrado neutrofílico de 2,05 ± 0,10 e expressão da caspase-3 na área perivascular de 4,30 ± 0,79; e menos intensas no grupo A3, com respectivas médias de 0,76 ± 0,16, 0,92 ± 0,10 e 0,67 ± 0,15 (p < 0,05). A caspase-3 mostrou-se mais expressiva no grupo B1 na área perivascular, com média de 4,30 ± 0,79, em comparação com o grupo B1 na área perinuclear, com média de 0,91 ± 0,32 (p < 0,05). CONCLUSÕES: As lesões são mais intensas quando o tempo de observação é maior após a reperfusão, e a pentoxifilina atenua essas lesões, sobretudo quando usada no início das fases de isquemia e de reperfusão.SBACVUniversidade Federal de Mato Grosso do Sul Hospital UniversitárioUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUFMSUNIFESP-EPM Departamento de PatologiaUFMS Departamento de Clínica CirúrgicaUFMS Hospital Universitário Comissão de Residência MédicaUNIFESP, EPM, Depto. de PatologiaSciEL

The Influence of Meteorology on the Spread of Influenza: Survival Analysis of an Equine Influenza (A/H3N8) Outbreak

The influences of relative humidity and ambient temperature on the transmission of influenza A viruses have recently been established under controlled laboratory conditions. The interplay of meteorological factors during an actual influenza epidemic is less clear, and research into the contribution of wind to epidemic spread is scarce. By applying geostatistics and survival analysis to data from a large outbreak of equine influenza (A/H3N8), we quantified the association between hazard of infection and air temperature, relative humidity, rainfall, and wind velocity, whilst controlling for premises-level covariates. The pattern of disease spread in space and time was described using extraction mapping and instantaneous hazard curves. Meteorological conditions at each premises location were estimated by kriging daily meteorological data and analysed as time-lagged time-varying predictors using generalised Cox regression. Meteorological covariates time-lagged by three days were strongly associated with hazard of influenza infection, corresponding closely with the incubation period of equine influenza. Hazard of equine influenza infection was higher when relative humidity was <60% and lowest on days when daily maximum air temperature was 20–25°C. Wind speeds >30 km hour−1 from the direction of nearby infected premises were associated with increased hazard of infection. Through combining detailed influenza outbreak and meteorological data, we provide empirical evidence for the underlying environmental mechanisms that influenced the local spread of an outbreak of influenza A. Our analysis supports, and extends, the findings of studies into influenza A transmission conducted under laboratory conditions. The relationships described are of direct importance for managing disease risk during influenza outbreaks in horses, and more generally, advance our understanding of the transmission of influenza A viruses under field conditions

Bushfire preparation and recovery: A manual for livestock producers

The Black Summer bushfires of 2019–20 affected farms across six states of Australia and had a significant impact on the agricultural community, with thousands of farms affected by significant losses of livestock. Bushfire is a major threat to rural livestock production and over the coming years in Australia, fire intensity, frequency and size are all predicted to increase. In catastrophic fire conditions, leaving the farm may be the safest option for you. A bushfire may be more severe than you expect, as was experienced by many farmers during Black Summer. Fortunately, if it is safe to stay there are concrete steps you can take that are likely to help protect your livestock and farm as well as your own safety. Compared with producers who are unprepared, those who have a farm fire plan and appropriate equipment and training lose fewer livestock or suffer less infrastructure damage and can get back to business sooner after a fire. This manual provides the essential information you need as a livestock producer to prepare for and recover from bushfire

Feral pig populations are structured at fine spatial scales in tropical Queensland, Australia

Feral pigs occur throughout tropical far north Queensland, Australia and are a significant threat to biodiversity and World Heritage values, agriculture and are a vector of infectious diseases. One of the constraints on long-lasting, local eradication of feral pigs is the process of reinvasion into recently controlled areas. This study examined the population genetic structure of feral pigs in far north Queensland to identify the extent of movement and the scale at which demographically independent management units exist. Genetic analysis of 328 feral pigs from the Innisfail to Tully region of tropical Queensland was undertaken. Seven microsatellite loci were screened and Bayesian clustering methods used to infer population clusters. Sequence variation at the mitochondrial DNA control region was examined to identify pig breed. Significant population structure was identified in the study area at a scale of 25 to 35 km, corresponding to three demographically independent management units (MUs). Distinct natural or anthropogenic barriers were not found, but environmental features such as topography and land use appear to influence patterns of gene flow. Despite the strong, overall pattern of structure, some feral pigs clearly exhibited ancestry from a MU outside of that from which they were sampled indicating isolated long distance dispersal or translocation events. Furthermore, our results suggest that gene flow is restricted among pigs of domestic Asian and European origin and non-random mating influences management unit boundaries. We conclude that the three MUs identified in this study should be considered as operational units for feral pig control in far north Queensland. Within a MU, coordinated and simultaneous control is required across farms, rainforest areas and National Park Estates to prevent recolonisation from adjacent localities

Low total psoas area as scored in the clinic setting independently predicts midterm mortality after endovascular aneurysm repair in male patients

Preoperative sarcopenia is an established risk factor for poor outcomes after surgery. Methods for assessing sarcopenia are either complex, time consuming, or poorly validated. We aimed to assess the interobserver reliability of scoring psoas area at the level of the L3 vertebra and to evaluate whether sarcopenia scored by this simple and rapid method correlated with other fitness scoring methods or impacted on mortality and duration of stay for patients undergoing endovascular aneurysm repair (EVAR).We had access to 191 preoperative computed tomography scans of patients who underwent EVAR. For each scan the axial slice at the most caudal level of the L3 vertebra was extracted. Three observers independently calculated the combined cross-sectional area of the left and right psoas muscle at this level. Interobserver variability was calculated as per Band and Altman. Psoas area was normalized for patient height with sarcopenia defined as total psoas area of <500 mm(2)/m(2). The effect of sarcopenia on patient survival was assessed using Cox proportional hazards models. Kaplan-Meier curves are also presented.Interobserver reliability of scoring psoas area was acceptable (reproducibility coefficient as percent of mean for each observer pair: 7.92%, 7.95%, and 14.33%). Sarcopenic patients had poorer survival (hazard ratio, 2.37; P = .011) and an increased hospital duration of stay (4.0 days vs 3.0 days; P = .008) when compared with nonsarcopenic patients. Sarcopenic patients were more likely to self-report as unfit (12.4% vs 33.3%; P = .004). Sarcopenia did not correlate with an increased rate of postprocedure complications.Psoas area scoring has good interobserver reliability. Preoperative sarcopenia as defined by psoas area was associated with poorer survival and of longer length of stay. As all patients being worked up for an endovascular aortic aneurysm repair will undergo a computed tomography scan, this method is a rapid and effective way to highlight patients in the clinic setting who have an increased risk of morbidity and mortality after EVAR.Benjamin Thurston, Guilherme N. Pena, Stuart Howell, Prue Cowled and Robert Fitridg

A novel-molecular ecology approach to ascertaining emigration/immigration and potential disease spread in feral pigs

Our study used two consecutive years of aerial culling then molecular ecology techniques (microsatellite analysis) to obtain parentage data from a widely dispersed and low density feral pig population during drought conditions in the semi-arid rangelands of Australia. This data was analysed geo-spatially to provide estimates on the actual minimum movements of feral pigs. The aim of this exercise was to obtain data that could be used to improve models that investigate rates of disease spread. The derived data revealed that some individuals will move much greater distances than previously recorded. The maximum recorded movement was 143km between a boar and pregnant sow in less than 1 year, with the mean boar to successfully mated sow distance being 43km. Thus, home ranges in this situation could be assumed to be much larger than previously calculated. Movement models were developed from this data and were based upon three assumptions of home range affinity; fixed home range, moving home range and no home range. Mean daily movements generated were 3km linear distance away from a previous mating for boars. Models revealed that currently planned disease eradication zones for Australia may be inadequate if an exotic disease outbreak remains undetected for only a short period of time (1 week). Using previously generated deterministic models for foot–and-mouth disease spread, and this data to alter home range size, the threshold population density below which disease will not transmit declines markedly

Independence of extent of tortuosity and calcification in iliac arteries

Abstract not availableNicholas Dowson, Benjamin Thurston, Prue Cowled, Margaret Boult, Robert Fitridg