Biomedical subjects
James Wood
Publications and source records attributed to James Wood.
Exercise distance and speed affect the risk of fracture in racehorses.
In order to gain insight into those training regimens that can minimise the risk of fracture in athletic populations, we conducted a large epidemiological study in racehorses. Thoroughbred racehorses provide a suitable model for studying fracture development and exercise-related risk factors in physically active populations. They represent a homogeneous population, undertaking intensive exercise programmes that are sufficiently heterogeneous to determine those factors that influence injury risk. Daily exercise information was recorded for a cohort of 1178 thoroughbreds that were monitored for up to 2 years. A total of 148 exercise-induced fractures occurred in the study population. Results from a nested case-control study showed a strong interactive effect of exercise distances at different speeds on fracture risk. Horses that exceeded 44 km at canter (< or =14 m/s) and 6 km at gallop (>14 m/s) in a 30-day period were at particularly increased risk of fracture. These distances equate to ca. 7700 bone loading cycles at canter and 880 loading cycles at gallop. Fifty-six fractures occurred in the subset of study horses that were followed since entering training as yearlings, when skeletally immature (n = 335). Cohort analysis of this data set showed that, in previously untrained bones, accumulation of canter exercise increased the risk of fracture (P < or = 0.01), whereas accumulation of high-speed gallop exercise had a protective effect (P < 0.01). However, increasing distances at canter and gallop in short time periods (up to one month) were associated with an increasing fracture risk. All training exercise involves a balance between the risk of fracture inherent in exposure to loading and the beneficial effect that loading has by stimulating bone cells to produce a more robust architecture. Results from our study provide important epidemiological evidence of the effects of physical exercise on bone adaptation and injury risk and can be used to inform the design of safer exercise regimens in physically active populations.
Effect of immune serum and role of individual Fcgamma receptors on the intracellular distribution and survival of Salmonella enterica serovar Typhimurium in murine macrophages.
Immune serum has a protective role against Salmonella infections in mice, domestic animals and humans. In this study, the effect of antibody on the interaction between murine macrophages and S. enterica serovar Typhimurium was examined. Detailed analysis at the single-cell level demonstrated that opsonization of the bacteria with immune serum enhanced bacterial uptake and altered bacterial distribution within individual phagocytic cells. Using gene-targeted mice deficient in individual Fc gamma receptors it was shown that immune serum enhanced bacterial internalization by macrophages via the high-affinity immunoglobulin G (IgG) receptor, Fc gamma receptor I. Exposure of murine macrophages to S. enterica serovar Typhimurium opsonized with immune serum resulted in increased production of superoxide, leading to enhanced antibacterial functions of the infected cells. However, opsonization of bacteria with immune serum did not increase either nitric oxide production in response to S. enterica serovar Typhimurium or fusion of phagosomes with lysosomes.
Inhibition of beta-oxidative respiration is a therapeutic window associated with the cancer chemo-preventive activity of PPARgamma agonists.
We demonstrate expression and coordinate induction of PPARgamma and lipogenic enzymes (HMG-CoA synthase, HMG-CoA reductase and fatty acid synthase) in a murine lung alveolar carcinoma cell line (Line 1) treated with the PPARgamma agonist troglitazone (TRO) [0-100 microM]. We postulate that TRO induces a shift in cellular energy metabolism towards fatty acid oxidation (beta-oxidative respiration). Accordingly, co-treatment with TRO [30 microM] and increasing concentrations of trimetazidine (TMZ) [0.1-3 mM], an inhibitor of beta-oxidation, results in a dose dependent decrease cellular ATP levels and a dose dependent induction of apoptosis. These findings, suggest that inhibition of beta-oxidative respiration is a therapeutic window associated with the cancer chemo-preventive activity of PPARgamma agonists.
Management of blunt splenic trauma.
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Back problems and lameness in horses.
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Survey of purebred dogs in the UK.
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Was the Black Death yersinial plague?
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Genotyping of porcine endogenous retroviruses from a family of miniature swine.
The identification of animals in an inbred miniature swine herd that consistently fail to produce replication- competent humantropic porcine endogenous retrovirus (PERV) has prompted studies on the biology of PERV in transmitter and nontransmitter animals. We analyzed PERV RNA transcript profiles in a family of inbred miniature swine (SLA(d/d) haplotype) in which individual members differed in their capacity to generate humantropic and ecotropic (i.e., pigtropic) virus. We identified unique HaeIII and HpaII gag restriction fragment length polymorphism (RFLP) profiles resulting from single nucleotide polymorphisms in blood cells; these were found only in animals that produced humantropic PERV. These HaeIII and HpaII gag RFLP profiles proved to be components of humantropic PERV as they were transmitted to 293 human target cells in vitro. The humantropic HaeIII and HpaII gag RFLP genotypes in the family of study were not present in other miniature swine in the herd that produced humantropic PERV, indicating that these RFLP profiles relate specifically to this family's lineage.
Packaging of human endogenous retrovirus sequences is undetectable in porcine endogenous retrovirus particles produced from human cells.
The chronic shortage of human donor organs and tissues for allotransplantation could be relieved if clinical xenotransplantation were to become a viable clinical therapy. Balanced against the benefits of xenotransplantation are the possible consequences of zoonotic infections, and in particular, infection by porcine endogenous retrovirus (PERV). An often-proclaimed risk of PERV infection is the possible recombination of PERV with human endogenous retroviruses (HERV). To address this issue, we examined the potential for HERV sequences to be cross-packaged into PERV particles produced from infected human 293 cells. Although HERV-K, W, E, R, and ERV-9 RNA transcripts are expressed in 293 cells, we did not detect cross-packaging of any of these HERV groups. Quantitative analysis indicated that less than approximately 1 in 10(4)-10(7) PERV particles might contain HERV sequences. In comparison, we found that murine leukemia virus (MLV)-based vector transcripts were cross-packaged at a rate of approximately one copy in 10(4) PERV particles. Our results indicate that the potential for recombination of PERV and HERV sequences is low and that novel viruses generated by this mechanism are unlikely to represent a significant risk for xenotransplantation.
Was the Black Death yersinial plague?
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Perioperative anaesthetic complications in cats and dogs.
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West Nile virus infection of horses.
West Nile virus (WNV) is a flavivirus closely related to Japanese encephalitis and St. Louis encephalitis viruses that is primarily maintained in nature by transmission cycles between mosquitoes and birds. Occasionally, WNV infects and causes disease in other vertebrates, including humans and horses. West Nile virus has re-emerged as an important pathogen as several recent outbreaks of encephalomyelitis have been reported from different parts of Europe in addition to the large epidemic that has swept across North America. This review summarises the main features of WNV infection in the horse, with reference to complementary information from other species, highlighting the most recent scientific findings and identifying areas that require further research.