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Biomedical subjects

S W Reid

Publications and source records attributed to S W Reid.

At least 37 records · Page 2Linked to original sources
PubMed1999

Impact of injuries and disease on a cohort of two- and three-year-old thoroughbreds in training.

A prospective study of injuries and disease in a cohort of Australian thoroughbreds in training was conducted with the participation of 24 trainers. From the horses catalogued at a major yearling sale in 1995, 169 were enrolled in the study and followed through their two- and three-year-old racing seasons. The principal aim was to quantify the time lost in training as a result of the various categories of injuries and disease, recorded as either days of modified training, or weeks rested at pasture. Shin soreness was the most common condition in two-year-olds (affecting 42 per cent of the horses that had entered training), followed by fetlock problems (25 per cent), and coughs and nasal discharge (16 per cent). Lameness, excluding lacerations and traumatic injuries, was the most common reason for lost training days (56.2 per cent of total days modified) and for resting horses at pasture (81.2 per cent of total weeks rested for injury or disease). Of the individual categories of injury or disease, lacerations and traumatic injuries, coughs and nasal discharge, shin soreness, carpal problems and fetlock problems were the most important causes of modified training days. In terms of weeks rested at pasture, fetlock problems, shin soreness, carpal problems, and coughs and nasal discharge had the greatest impact. Major injury was uncommon in young horses in training, but there was a high incidence of relatively low-grade injuries and disease during the training of two-year-olds.

Animal Husbandry↗
PubMed1999

Modelling the spread of a viral infection in equine populations managed in Thoroughbred racehorse training yards.

A Monte Carlo model that simulates the management life cycle of a horse population in training on a Thoroughbred flat racing yard (i.e. stable) was developed for computer implementation. Each horse was characterised by several state variables. Discrete events at the horse level were triggered stochastically to reflect uncertainty about some input assumptions and heterogeneity of the horse population in a particular yard. This mathematical model was subsequently used to mimic the spread of equine influenza (EI) within a typical yard following the introduction of one or several infectious horses. Different scenarios were simulated to demonstrate the value of strategies for preventing outbreaks of EI. Under typical UK management conditions and vaccination protocols, the model showed that EI would propagate and that the timing of vaccination in connection with the racing season and the arrival of new horses was a critical factor. The predicted outcomes (based on published characteristics of one EI vaccine) suggested that vaccination in mid-December with boosters in June and September was a viable and successful strategy in preventing the spread of EI in a training establishment.

Animals↗
PubMed1999

Demographic characteristics of the equine population of northern Britain.

The size, composition and distribution of the equine population of Scotland and the five northernmost counties in England were estimated through a series of mailed questionnaire surveys of sentinel veterinary practices and horse owners. An estimated 96,622 equine animals were kept by an estimated 26,114 owners. The mean (sd) age of the population was 11.0 (7.5) years (range one month to 37 years). Thoroughbred or thoroughbred-cross animals were the most numerous, constituting 30 per cent (95 per cent confidence interval 27 to 33 per cent) of the total population. The ratio of males:females was 1:1.

Animals↗
PubMed1999

Nucleotide sequence of the porcine p53 cDNA, and the detection of recombinant porcine p53 expressed in vitro with a variety of anti-p53 antibodies.

The cDNA of porcine p53 was cloned and sequenced by a reverse transcriptase polymerase chain reaction (RT - PCR) approach with primers based on regions of homology between all known p53 sequences. The p53 cDNA was found to be 87% conserved to human p53 and 86% conserved to bovine p53 at the nucleotide level. The porcine p53 sequence was inserted into an expression vector and recombinant protein expressed in vitro. An approximately 50 kDa protein was detected by Western blotting using both polyclonal and monoclonal anti-p53 antibodies. The sequence data of porcine p53 and the ability to detect expressed protein with various anti-p53 antibodies will allow the p53 status of the pig population, and the role of p53 in porcine tumours, to be assessed. An understanding of tumour development in the pig may be important if pig cells, tissues or organs are to be used in the treatment of humans.

Amino Acid Sequence↗
PubMed1999

Value of direct smears of synovial fluid in the diagnosis of canine joint disease.

Assessments of direct smears of synovial fluid by four clinicians were compared with the results obtained with a Coulter counter. Estimates of total white cell counts by the clinicians were inaccurate and generally higher than the Coulter counter results. The method had a low sensitivity and specificity for the identification of degenerative joint disease and normal joints in comparison with the identification of inflammatory joint disease. There were marked variations in the results obtained by the four clinicians for all the analyses in the study.

Animals↗
PubMed1999

Acute phase proteins in cattle: discrimination between acute and chronic inflammation.

Acute phase proteins such as serum amyloid A, haptoglobin, and alpha 1-acid glycoprotein have been identified as markers of inflammation in cattle because they are produced by the liver in response to pro-inflammatory cytokines. This study was designed to assess whether they could be used to discriminate between acute and chronic inflammation. Their concentrations were measured in serum samples from 81 cattle in which inflammation was classified by thorough clinical examination, supported by postmortem findings, as being acute in severity in 31 and chronic in 50. The classical haematological markers of inflammation were also determined in blood from the animals. Serum amyloid A had a maximum (100 per cent) clinical sensitivity in discriminating between the acute and chronic cases, and haptoglobin had the highest clinical specificity of 76 per cent; counts of neutrophils and band neutrophils had sensitivities of 71 per cent and 42 per cent and specificities of 30 per cent and 72 per cent, respectively. It was concluded that serum amyloid A and haptoglobin may be used to discriminate between acute and chronic inflammatory conditions.

Acute Disease↗
PubMed1999

Bovine papillomaviral gene expression in equine sarcoid tumours.

The sarcoid is a benign locally invasive dermal fibroblastic lesion, commonly affecting horses and donkeys. The aetiology of the equine sarcoid is equivocal. Bovine papillomaviral (BPV) DNA (type 1/2) is frequently demonstrable in equine sarcoid tumour biopsies. However, the exact role of the virus in the disease process and its contribution to the phenotypic differences in sarcoids is not known. It was sought to assess the transcriptional activity of BPV-1 found in sarcoid tissues. Of 20 tumours examined, 18 were positive for E2 expression and ten positive for L1 expression. Viral oncogenes E5, E6 and E7 transcripts were detected in 16, nine and 12 tumours, respectively. This study demonstrates BPV gene expression in equine sarcoids and provide the first evidence for a direct involvement of the virus in the pathogenesis of sarcoids.

Animals↗
PubMed1999

Engineering a soluble extracellular erythropoietin receptor (EPObp) in Pichia pastoris to eliminate microheterogeneity, and its complex with erythropoietin.

The extracellular ligand-binding domain (EPObp) of the human EPO receptor (EPOR) was expressed both in CHO (Chinese Hamster Ovary) cells and in Pichia pastoris. The CHO and yeast expressed receptors showed identical affinity for EPO binding. Expression levels in P. pastoris were significantly higher, favoring its use as an expression and scale-up production system. Incubation of EPO with a fourfold molar excess of receptor at high protein concentrations yielded stable EPO-EPObp complexes. Quantification of EPO and EPObp in the complex yielded a molar ratio of one EPO molecule to two receptor molecules. Residues that are responsible for EPOR glycosylation and isomerization in Pichia were identified and eliminated by site-specific mutagenesis. A thiol modification was identified and a method was developed to remove the modified species from EPObp. EPObp was complexed with erythropoietin (EPO) and purified. The complex crystallized in two crystal forms that diffracted to 2.8 and 1.9 A respectively. (Form 1 and form 2 crystals were independently obtained at AxyS Pharmaceuticals, Inc. and Amgen, Inc. respectively.) Both contained one complex per asymmetric unit with a stoichiometry of two EPObps to one EPO.

Animals↗
PubMed1999

Comparison of bacteriology and cytology of tracheal fluid samples collected by percutaneous transtracheal aspiration or via an endoscope using a plugged, guarded catheter.

Cytological and bacteriological results from tracheal fluid samples obtained endoscopically using a telescoping, plugged catheter (TPC) were compared with results from samples collected by percutaneous transtracheal aspiration (PTA). The TPC technique and PTA were performed in random order on 9 healthy Standardbred geldings. Three weeks later the procedures were performed on the same horses in the reverse order. The presence of oropharyngeal contamination was determined by quantitative bacteriology and quantification of squamous epithelial cells (SEC)/ml sample. The relative numbers of macrophages, haemosiderophages, giant cells, neutrophils, lymphocytes and eosinophils did not differ between techniques. The number of SEC/ml was greater in samples with more colony forming units/ml indicating that quantification of SEC provides evidence of the probable degree of oropharyngeal contamination. Fifteen out of the 18 TPC samples were free of contamination, indicating that the TPC can provide adequate samples for bacteriology. The results also indicate that tracheoscopy sometimes results in oropharyngeal contamination of the trachea, but that this does not affect the results of the TPC sample.

Animals↗
PubMed1999

Real-time measurement of cardiac vagal tone in conscious dogs.

Rapid changes in heart rate are caused by changes in parasympathetic tone. The NeuroScope is an electronic device designed to offer an objective real-time measure of instantaneous cardiac vagal tone by phase demodulation of a high-resolution time domain of R-R wave intervals. Data are displayed against an arbitrary but linear scale, the cardiac index of parasympathetic activity (CIPA). To validate this method, 10 conscious healthy dogs were each given six incremental doses of atropine (0.01 mg/kg) to a total dose of 0.06 mg/kg or equal volumes of saline. A dose-response curve was constructed. At the maximum dose of atropine, CIPA values fell to 1. 3 +/- 0.7% (SD) of baseline, whereas R-R intervals fell to 51.5 +/- 11.5% of baseline, and standard deviation of the R-R wave interval fell to 10.6 +/- 6.5% of baseline. These findings show that the NeuroScope can provide a specific real-time index of cardiac vagal tone in dogs without need for recourse to atropine.

Animals↗
PubMed1999

Factors associated with time until first race and career duration for Thoroughbred racehorses.

OBJECTIVE: To determine whether sex or foaling period were associated with time to first race start and whether sex, age at time of first race start, or inter-race period were associated with career duration for Thoroughbred racehorses in Australia. ANIMALS: 553 Thoroughbred racehorses. PROCEDURE: Race records through to the end of the 6-year-old racing season were obtained for each horse. Product-limit survival analysis was used to determine whether sex or foaling period was associated with time to first race start and whether sex or age at first race was associated with career duration. A Cox proportional hazards model was used to determine whether sex, age at first possible race, age at first race, or inter-race period was associated with time to first race start or career duration. RESULTS: 472 horses (85.4%) raced. Time to first race start was not associated with sex or foaling period. However, males, who had their first race at a younger age and a greater mean number of rest days between races, had longer careers. The hazard ratio for career duration of males versus females, controlling for age at time of first race and inter-race period (0.27), confirmed that males had a higher probability of a long racing career. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that for Thoroughbred racehorses, sex and time of birth during the foaling season were not associated with time to first race. Male Thoroughbred racehorses that were raced less intensively or raced at a younger age were more likely to have long racing careers.

Age Factors↗
PubMed1998

Efficiency of signalling through cytokine receptors depends critically on receptor orientation.

Human erythropoietin is a haematopoietic cytokine required for the differentiation and proliferation of precursor cells into red blood cells. It activates cells by binding and orientating two cell-surface erythropoietin receptors (EPORs) which trigger an intracellular phosphorylation cascade. The half-maximal response in a cellular proliferation assay is evoked at an erythropoietin concentration of 10 pM, 10(-2) of its Kd value for erythropoietin-EPOR binding site 1 (Kd approximately equal to nM), and 10(-5) of the Kd for erythropoietin-EPOR binding site 2 (Kd approximately equal to 1 microM). Overall half-maximal binding (IC50) of cell-surface receptors is produced with approximately 0.18 nM erythropoietin, indicating that only approximately 6% of the receptors would be bound in the presence of 10 pM erythropoietin. Other effective erythropoietin-mimetic ligands that dimerize receptors can evoke the same cellular responses but much less efficiently, requiring concentrations close to their Kd values (approximately 0.1 microM). The crystal structure of erythropoietin complexed to the extracellular ligand-binding domains of the erythropoietin receptor, determined at 1.9 A from two crystal forms, shows that erythropoietin imposes a unique 120 degrees angular relationship and orientation that is responsible for optimal signalling through intracellular kinase pathways.

Crystallography, X-Ray↗
PubMed1998

Studies on host resistance to tick infestations among trypanotolerant Bos indicus cattle breeds in east Africa.

Recent epidemiological studies carried out in East Africa have indicated that some Bos indicus cattle breeds such as the Orma Boran and Maasai Zebu have a degree of trypanotolerance worth exploitation by their introduction into trypanosomosis endemic areas where other cattle breeds cannot survive. However, in most areas of East Africa, trypanosomosis, ticks, and tick-borne diseases occur together. It is therefore important to obtain information on the susceptibility of these breeds to tick infestation and tick-borne diseases. This study was therefore designed to determine the susceptibility of these cattle breeds to tick infestations. They were compared with the Galana Boran (trypanosusceptible) and the Friesian (susceptible to tick infestations, tick-borne diseases, and trypanosomosis). The four breeds of cattle were exposed to natural tick challenge for a period of seven months and whole body weekly tick counts were done on each animal. Significant differences to tick infestations among the four breeds were observed. For both Rhipicephalus appendiculatus and Boophilus decoloratus, susceptibility to infestation increased in the order, Maasai Zebu, Orma Boran, Galana Boran and Friesian. The results generated by this pilot study so far suggest that variation in susceptibility to tick infestations exists among the four breeds. The Orma Boran and Maasai Zebu showed greater resistance to tick-infestations than the Galana Boran and Friesian. This suggests that utilization of these trypanotolerant cattle breeds could be feasible even in the face of tick challenge and should therefore be considered when planning integrated trypanosomosis and tick control strategies.

Africa, Eastern↗
PubMed1998

Application of probability techniques to the objective interpretation of veterinary clinical biochemistry data.

Methods for the interpretation of veterinary clinical biochemistry have not developed as rapidly as biochemical technology. However, the results of clinical biochemistry tests are only of value when they are interpreted appropriately. A retrospective study was undertaken to investigate the equine biochemistry data which had been stored in a veterinary hospital database. By applying percentile analysis and Bayesian probability methods to the clinical biochemistry and corresponding diagnosis data, a novel method for the interpretation of clinical biochemistry data has been developed. The method allows clinicians to determine whether a biochemistry value is abnormal, its degree of abnormality, and the most likely associated diagnoses. The method could be used to investigate a practice-based population and may have significant implications for the interpretation of clinical biochemistry data in veterinary medicine in the future.

Animals↗
PubMed1998

Objective interpretation of bovine clinical biochemistry data: application of Bayes law to a database model.

With the advent of animal-side biochemistry analysers in veterinary practice, the requirement for ready access to reliable means for interpretation of the results is of increasing importance. At the University of Glasgow Veterinary School (GUVS), a large computerised hospital database containing extensive clinical, laboratory, and pathological information has been maintained. A retrospective study was undertaken to investigate plasma biochemistry results and corresponding post mortem diagnosis data from 754 unwell cattle which had presented to GUVS over the study period. Initial analysis of the clinical biochemistry data from this unwell population revealed that the parameters did not follow a normal distribution. This finding suggested that the accepted reference range method for the interpretation of clinical biochemistry data may provide limited information about the unwell animal. By applying a combination of percentile analysis and conditional probability techniques to the hospital data, the development of a means of clinical biochemistry interpretation was developed whereby a clinician could determine whether a value was abnormal, the degree of abnormality, and the most likely associated diseases. For example, a urea value of 30 mmol/l lay within the top 5% of results, and one of the most common diseases associated with this urea value was pyelonephritis. Furthermore, a Bayesian approach allowed the quantification of the relationship between any plasma biochemistry value and disease through the generation of a ratio termed the 'biochemical factor'. Using the same example, given a urea value of 30 mmol/l, pyelonephritis was eight times more likely than before any biochemistry information was known. The results from the study were used to form the basis of a software system which may ultimately be used by the clinical to aid in the recognition, treatment and prevention of disease in the veterinary domain.

Animals↗
PubMed1998

Susceptibility to trypanosomosis of three Bos indicus cattle breeds in areas of differing tsetse fly challenge.

Studies to assess the differences in susceptibility to trypanosomosis among Bos indicus cattle breeds (Maasai Zebu, Orma Boran and Galana Boran) were conducted under conditions of varying tsetse fly challenge at the Nguruman escarpment in south-western Kenya, for a period of 1 year. It was found that under tsetse challenge quantified as high, Maasai Zebu and Orma Boran were less susceptible than Galana Boran to trypanosome infections, as judged by the significantly lower incidence of infection, development of less severe anaemia, fewer requirements for trypanocidal drug treatments, higher growth rates and fewer mortalities. In the area where tsetse challenge was considered low as a result of a tsetse fly control operation using odour-baited traps, only the Maasai Zebu and Orma Boran were compared. No significant differences in the incidence of infection, degree of anaemia or growth rates were observed between the two breeds, but all were significantly different from their counterparts in the high tsetse challenge area. These results suggest that there is variation in resistance to trypanosomosis among Bos indicus cattle breeds that could be exploited as part of the integrated trypanosomosis control programmes in East Africa.

Anemia↗