Biomedical subjects
R J Rose
Publications and source records attributed to R J Rose.
Bioavailability of phenylbutazone preparations in the horse.
Plasma phenylbutazone concentrations were determined for up to 12 h in 6 horses following intravenous and oral phenylbutazone administration. To evaluate the bioavailability of different oral preparations, phenylbutazone was administered in a paste as well as the traditional powder form. The effect of the state of stomach contents on the absorption of phenylbutazone was investigated by administering the paste before and after feeding; the powder was given in a small bran mash and a full feed of lucerne chaff, wheaten chaff and bran. Despite great variability among individual horses both the paste form of phenylbutazone administered before a meal and the powder given in a small bran mash appeared to be almost completely absorbed, However, phenylbutazone paste administered after feeding or phenylbutazone powder given in a full feed resulted in lower peak plasma phenylbutazone levels than when administered on an empty or relatively empty stomach.
Blood gas and acid--base status in spontaneously delivered, term-induced and induced premature foals.
Six spontaneously delivered foals, 8 Thoroughbred foals induced at term with fluprostenol and 17 Pony foals induced prematurely with fluprostenol and oxytocin at a gestational age of 270 to 330 days were studied to determine PO2, PCO2, pH, base excess and HCO3 values in arterial blood between birth and 7 days of age. The Pony foals were subdivided into those that survived greater than 24 h (N = 9) and less than 9 h (N = 8). Blood gas and acid base values in the term-induced foals were similar to those in spontaneously delivered foals. The induced premature foals surviving greater than 24 h had significantly lower PaO2 values at 15 min, 30 min and 1 h after birth than did the term-induced foals. There were no significant differences in PaCO2 or pHa values between these groups at any measurement time. However, the premature foals had significantly lower base excess values than did the term-induced foals at birth and 30 min after birth. The induced premature foals surviving less than 9 h had significantly lower PaO2 values than did the term-induced foals at all measurement times. At the 1.5-4 h measurement, the foals surviving less than 9 h had PaO2 values significantly lower than those of the foals surviving greater than 24 h. The PaCO2 values were significantly higher and the pHa values significantly lower in the foals surviving less than 9 h than in either of the other 2 groups.
Changes in certain metabolic parameters in horses associated with food deprivation and endurance exercise.
Total and individual non-esterified fatty acids (NEFA), pyruvate, lactate, alpha ketoglutarate, acetoacetate, beta hydroxybutyrate, glucose and insulin were measured in horses during an 80 km endurance ride and during four days of food deprivation. In the latter group venous blood-gas and acid-base parameters, and plasma cortisol concentrations were also measured. During exercise and food deprivation the NEFA became considerably elevated, the predominant of which were oleic (35 per cent), palmitic (24 per cent), linoleic (19 per cent) and linolenic (10 per cent). By one hour after feeding total NEFA fell to approximately 20 per cent of 12 hour fasting concentrations. This was associated with a four fold rise in insulin. Small though significant increases occurred in lactate, acetoacetate and beta hydroxybutyrate after the 80 km endurance ride. It was concluded that a ketone pathway is relatively unimportant in the horse, probably due to the ability of the liver to maintain glycogenolysis.
Lack of cytosol and nuclear estrogen receptors in human spermatozoa.
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Muscle fibre composition and glycogen depletion in horses competing in an endurance ride.
An investigation into fibre composition and glycogen depletion pattern within the middle gluteal of 16 horses participating in an 80 km endurance ride was carried out. Although the proportion of slow twitch high oxidative (ST) fibres in the horses varied between 7 and 38 per cent, it was found that the horses with the highest proportion of these fibres usually had the best performance records. The cross-sectional area of the fast twitch low oxidative (FT) fibres was greatest, with the ST and fast twitch high oxidative (FTH) being similar in size. Most marked histological evidence of glycogen depletion after the ride was in the ST fibres, which were apparently totally depleted. A variable degree of depletion was found in both the FTH and FT fibres. Biochemical measurement of muscle glycogen showed a 56 +/- 7.2 per cent (mean +/- SEM) decrease in content.
Twin-family studies of perceptual speed ability. II. Parameter estimation.
Offspring of monozygotic (MZ) twins form half-ships that permit a direct test of maternal effects and differentiate several sources of between-family environmental variance. Combined with conventional twin data, these genetic half-sibships provide a unique data set for estimating sources of variation in quantitative traits. To illustrate, genetic and environmental parameters were estimated for Identical Pictures Test data obtained from children of MZ twin parents and an (approximate) age-matched cohort of like-sex twins. Analyses of variance of the data, standardized for age and sex, yield 12 mean squares to which gene-environment models were fit. Maximum-likelihood estimation revealed a complete absence of maternal influences and shared environmental effects; a simple two-parameter model, assuming random mating and attributing variation in test scores to additive genes and within-family environment, adequately accounts for the familial data.
The binding of sex steroids to human spermatozoa. An autoradiographic study.
The locations of steroid binding sites with specificities for 17 beta-oestradiol, progesterone and testosterone have been examined on human spermatozoa by autoradiography. The binding sites were not evenly distributed over the entire surface of human spermatozoa. They were more densely located on the midpiece of the tail, less on the head and neck, and least on the principal- and end pieces of the tail. The binding sites for 17 beta-oestradiol were specific, with 3H-17 beta-oestradiol being displayed by unlabelled 17 beta-oestradiol, but less readily displaced by either progesterone or testosterone. The binding sites for testosterone were less specific than those for 17 beta-oestradiol or those for progesterone. Both 17 beta-oestradiol and progesterone were good competitors for testosterone binding sites, while the binding of 3H-progesterone was easily displaced by 17 beta-oestradiol, but less readily displayed by testosterone. Since there was preferential binding of these steroids to the mid-piece, and strong competition for binding between 17 beta-oestradiol and progesterone, these studies appear to provide information on the sites of action for the reported effects of these and related steroids on spermatozoal motility, migration and metabolism.
The binding of oestradiol-17beta to human spermatozoa - an electron microscope autoradiographic study.
The location of steroid binding sites with specificity for oestradiol-17beta at an ultrastructural level has been examined on human spermatozoa by electron microscope autoradiography. About 75% of the 438 gains produced by 3H-oestradiol-17beta, and counted on electron microscope autoradiographs, were found over the plasma membrane or within 1000 A of it. This study provides evidence suggesting that the plasma membrane is a site of action of oestradiol-17beta in human spermatozoa.
The pharmacokinetics of some aminoglycoside antibiotics in the horse.
The disposition kinetics and bioavailability of streptomycin, kanamycin and neomycin were determined following their administration as parenteral preparations to horses. Single doses (10 mg/kg) of each aminoglycoside were given by the intravenous (i.v.) and intramuscular (i.m.) routes and, at a later time, seven intramuscular doses were injected at 12-h intervals. The pharmacokinetic behaviour of the three aminoglycosides was similar, in that a rapid distribution phase was followed by a relatively short half-life. The half-life (mean +/- SD, n = 6) of kanamycin (1.80 +/- 0.17 h) was significantly (P less than 0.01; t test, 10 d.f.) shorter than that of streptomycin (3.40 +/- 0.42 h), while neomycin half-life (2.10 +/- 0.97 h) was of an intermediate length. The apparent volume of distribution of neither kanamycin nor neomycin varied significantly (P greater than 0.05) from that of streptomycin and numerically (V1 d congruent to 230 ml/kg) was the same as the extracellular fluid volume. The body clearance of kanamycin (88.5 +/- 11.3 ml/kg.h) was significantly (P less than 0.01) larger than that of streptomycin (47.5 +/- 7.9 ml/kg.h), while a significant difference in this parameter did not exist (P greater than 0.05) between neomycin and streptomycin. Following intramuscular injection, each aminoglycoside was rapidly and completely absorbed from the injection site, although neomycin showed wide individual variation in the fraction absorbed. The administration of multiple doses did not change either the bioavailability or the apparent half-life from the values obtained after a single dose. The only pharmacokinetic difference between these aminoglycosides that is of clinical importance lies in the rate of their elimination. A dosage interval of 8 h would be appropriate for kanamycin compared with a 12-h interval for streptomycin. The dosage interval for neomycin based on half-life should be 8 h but, due to the relatively greater toxicity of this aminoglycoside, an interval of 12 h might be recommended. The height of the peak serum concentration is determined by the size of the dose.
A physiological approach to fluid and electrolyte therapy in the horse.
In this article a physiological approach to fluid therapy is discussed, commencing with examination of fluid distribution in the normal horse. The functions of individual plasma electrolyte concentrations are considered and practical causes of acid-base disturbances discussed. When fluid administration is necessary, selection of the route for fluid administration as well as the type of fluid are important considerations and these must be adjusted to the needs of the individual case. Balanced polyionic solutions appear to be most suitable for general use because normal saline can produce hypokalaemia and metabolic acidosis. The use of bicarbonate is indicated mainly where there has been alkali loss (eg, diarrhoea) or severe acidosis associated with increased lactate production. Plasma volume expanders, such as dextran or gelatin polymers, can be considered where a rapid and prolonged restoration of blood volume is required. Fluids should be warmed to body temperature before administration and flow rates up to 6 to 8 litres/h may be safely used. A plan for fluid therapy involves the estimation of existing fluids, as an average horse will require almost 84,000 kJ continuing losses should be estimated and corrected. Maintenance of calorific requirements is difficult using intravenous fluids, as an average horse will require almost 84,000 kJ (20,000 kcal) per day. Lipid emulsions provide up to 8370 kJ/litre but their expense precludes the use of large volumes.
Serum levels of amoxycillin following its oral administration to thoroughbred foals.
Amoxycillin trihydrate was administered orally to 6 foals at dose rates of 13 mg/kg (low), 20 mg/kg (medium) and 30 mg/kg (high) and serum concentrations determined at intervals up to 8 h. Therapeutic serum levels of 1 microgram/ml persisted for 268 mins at a dose rate of 13 mg/kg, for 339 mins at 20 mg/kg and for 381 mins at 30 mg/kg. A 2 micrograms/ml serum level persisted for 198 mins at a dose rate of 13 mg/kg, for 268 mins at 20 mg/kg and for 311 mins at 30 mg/kg. To determine the spectra of its antibacterial activity, the minimum inhibitory concentrations of amoxycillin against 8 genera of common pathogenic bacteria in foals were examined. Of the bacteria tested, only Streptococcus equi, Strep zooepidemicus and Staphylococcus aureus (non-beta lactamase producing) would have been treated effectively with the serum levels which persisted in these foals. It is concluded that amoxycillin cannot be considered for broad spectrum use against pathogens likely to be encountered in the foal, but, because of its ease of administration orally, has a useful role in treating streptococcal infections and staphylococcal infections not caused by beta lactamase producers. If sensitivity testing of isolates is made, the drug may be useful also for treatment of some infections caused by the Gram-negative organisms Actinobacillus equuli and Salmonella typhimurium.
Techniques and clinical application of arterial blood collection in the horse.
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Laryngeal paralysis in Arabian foals associated with oral haloxon administration.
Bilateral laryngeal paralysis is described in 5 Arabian and part-Arabian foals aged between 23 and 35 days. Tracheotomies resulted in complete relief of dyspnoea. Two cases showed recovery of abductor function of the right arytenoid cartilage after 3 weeks and one of these cases later recovered left abductor function. Four of the foals were autopsied at various times from one week to 6 months after the onset of respiratory obstruction. Histology of the recurrent laryngeal nerves showed active Wallerian degeneration and loss of nerve fibres in many fascicles in cases affected for one to 2 weeks. In the longer standing cases there was a severe deficiency of myelinated fibres. Histology of the dorsal and lateral cricoarytenoid muscles showed no abnormalities in the cases affected from one to 5 weeks. However, in the foal affected for 6 months there was variation in fibre diameter in the left dorsal cricoarytenoid muscle; in sections stained for myosin ATPase there was evidence of muscle fibre type grouping in both left and right dorsal cricoarytenoid muscles. It is postulated that the most likely cause of the condition was oral haloxon administration which was given to the foals at a dose rate of 1 to 2 g at fortnightly intervals, beginning at 2 days of age.
Hormonal changes associated with long distance exercise.
The alteration in plasma concentration of a number of hormones was investigated following an 80 km endurance ride. A marked rise in plasma cortisol levels occurred in all 17 animals investigated. Although decreased glucose levels did not occur in all animals, insulin levels fell in all horses examined. A high correlation (r = 0.89) was found between post ride glucose and plasma insulin concentrations. The plasma levels of both noradrenaline and adrenaline were significantly elevated post ride.
Twin-family studies of common fears and phobias.
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Placentation effects on cognitive resemblance of adult monozygotes.
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Relevance of the marriages of twins to the causal analysis of nonrandom mating.
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