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Biomedical subjects

R J Rose

Publications and source records attributed to R J Rose.

At least 163 records · Page 9Linked to original sources
PubMed1987

Path analysis of seven fear factors in adult twin and sibling pairs and their parents.

A multivariate path model of genetic and environmental transmission, used to derive expected covariances among adult twin and sibling pairs and their parents, was fitted to fear factor data from 250 twin families and 91 sibling families, with the use of a maximum-likelihood estimation procedure. The full model, with 259 free parameters, provides for parental cultural transmission, common twin and sibling environment, genotype-environment correlation, direct assortative mating, and genetic and environmental correlations. Significant effects were indicated for heritable transmission of common fears and phobias, and a single genetic factor accounted for most of the genetic covariance among the traits. Moderately high levels of common twin environment and a small effect for direct isomorphic marital assortment were also found. There was no evidence for cultural transmission, genotype-environment correlation, or common sibling environment.

Biometry↗
PubMed1987

Design and sampling considerations, response rates, and representativeness in a Finnish Twin Family Study.

Kinships composed of twin parents, their spouses and children, offer a robust and flexible sampling design for research in genetic epidemiology. Families-of-twins designs circumvent some of the sampling problems that arise when independent data sets are combined, and these designs provide unique evaluations of maternal influences, assortative mating and X-linkage. Unfortunately, empirical studies of families of twin parents have been limited by relatively small samples and by the self-selection biases intrinsic in ascertainment of families from volunteer twin registries. A large and representative cohort of monozygotic and dizygotic twin parents, drawn from a population-based twin registry, provides the optimal sampling frame for twin-family research. This paper reviews the sampling considerations underlying the initial family study based on the Finnish Twin Cohort and evaluates the representativeness of the sampled twins. Spouses and adult children (over 18 years) of 236 pairs of twins, about equally divided by gender and zygosity, were evaluated by a postal questionnaire. Individual response rates exceeded 86% and in 464 of the 472 nuclear families (98.3%), at last one member of the twin's family completed the questionnaire. The sampled twins, selected for fecundity to maximize statistical power of the obtained data, were broadly representative of non-selected twins drawn from the Cohort, with whom they were matched on age, gender, and zygosity. Such results suggest that the Finnish Cohort has excellent potential for extended twin-family research designs.

Adolescent↗
PubMed1987

Genetic influences on use and abuse of alcohol: a study of 5638 adult Finnish twin brothers.

To evaluate genetic influences on the use and abuse of alcohol, we compared questionnaire measures of the frequency, quantity, and density of social drinking, and the frequency of alcohol-induced passouts self-reported by 879 monozygotic (MZ) and 1940 dizygotic (DZ) pairs of twin brothers, aged 24-49 yr. The measures of frequency, quantity, and density (heavy drinking once or more a month) significantly intercorrelate, and the self-reported alcohol consumption by this sample is satisfactorily stable and consistent with nationwide sales figures. None of the drinking measures was associated with twin type (zygosity), and only density correlated with age. Similarity of drinking habits among twin brothers was evaluated as a function of their genetic resemblance and age, the frequency of their social contact with one another, and the interactions of these terms. The effects were estimated from hierarchical linear regressions of a double-entry data matrix from which each twin's drinking was predicted from that of his twin brother, and that pair's age, zygosity, cohabitation status, and frequency of social contact. Significant genetic variance was found for each of the drinking measures with heritability estimates ranging from 0.36 to 0.40. Co-twins in more frequent social contact with one another reported greater similarity in their use of alcohol, but heritable variance remained after the effects of age and social contact were removed from both mean levels and co-twin resemblance. Reported frequency of passouts yielded significant, but equivalent, correlations in both MZ and DZ twins and no evidence of genetic influence.

Adult↗
PubMed1987

The distribution of ventilation-perfusion ratios in the lungs of newborn foals.

The distributions of ventilation-perfusion ratios, and the effects of 100% oxygen administration on the distributions, were studied in 3 foals from 4h to 9 days of age, using the multiple inert gas elimination technique. The distributions were calculated from the pulmonary clearance of 6 inert gases following infusion into a peripheral vein of a solution containing the inert gases. The results from a total of 8 studies showed several consistent features. The major findings were (i) the absence of low ventilation-perfusion ratios, i.e. regions where blood flow was greatly in excess of ventilation; (ii) the presence of variable right to left shunt; (iii) a reduction in this shunt with increasing post-natal age; (iv) the presence of a separate high mode of ventilation-perfusion ratios where ventilation was greatly in excess of blood flow and; (v) the observation that breathing enriched oxygen mixtures for 40 min did not increase the right to left shunt in any foal at any age studied. These studies indicate that hypoxaemia in the neonatal foal is attributable to right to left shunt which may be intrapulmonary or intracardiac, or both, rather than overperfusion of poorly ventilated lungs.

Age Factors↗
PubMed1987

Social and genetic influences on drinking patterns of adult men: a study of 5638 Finnish twin brothers.

Hierarchical multiple regression analyses of questionnaire data reported by male twins in the Finnish Twin Cohort were used to evaluate genetic and social influences on use and abuse of alcohol. The similarity in drinking patterns of twin brothers is related to the frequency of their social interaction, and monozygotic co-twins are in more frequent social contact. But the stepwise multiple regressions show that the greater social interaction of identical twins cannot account for their greater similarity in drinking patterns. We conclude that genetic variance significantly contributes to population variance in the frequency, quantity, and density of social drinking.

Adult↗
PubMed1987

Responses of horses to acepromazine maleate administered orally in a paste.

The effects of acepromazine maleate (ACP), given orally in a paste form, were examined in six standard-bred geldings over a 12 hour period. Three dose rates, zero (placebo paste), 0.13 mg kg-1 and 0.26 mg kg-1, given before or after feeding, were investigated. The data were divided into two sampling periods for analysis, one from zero to 120 minutes and the other from four to 12 hours. Sedation was assessed by a score (TS score) based on general appearance, anal sphincter relaxation and penile protrusion. This TS score was significantly elevated 40 minutes after dosing with ACP, irrespective of whether the horses had been fed or not. Dose rate had no significant effect on TS in the zero to 120 minute sampling period, but the TS score was significantly (P less than 0.01) higher at the higher dose rate in the four to 12 hour period. At both dose rates, the TS scores were still significantly higher than their pretreatment values 12 hours after dosing. Systolic blood pressure (SBP), measured indirectly from the coccygeal artery, haematocrit (PCV) and total plasma protein concentration (TPP) were also examined. ACP caused significant falls in SBP and PCV, but the effect was complicated by feeding. ACP given after feeding had a reduced effect on SBP and PCV. Feeding appeared to cause a rise then a fall in PCV and TPP which was superimposed upon the fall caused by ACP. There was no difference between the two dose rates of ACP on SBP and PCV.(ABSTRACT TRUNCATED AT 250 WORDS)

Acepromazine↗
PubMed1986

An evaluation of an oral glucose-glycine-electrolyte solution for the treatment of experimentally induced dehydration in the horse.

Five standardbred geldings were given 1 mg/kg bodyweight of frusemide by intramuscular injection to induce mild dehydration. After food and water deprivation overnight, the mean weight loss was 24.4 +/- 1.8 kg (5.5 per cent of bodyweight). The horses were then given an equivalent volume of an oral glucose-glycine-electrolyte solution by stomach tube. No more than 10 litres was given every 30 minutes until the calculated bodyweight loss had been replaced. Measurements made before, during and after the fluid administration included bodyweight, arterial blood haematocrit, PCO2, pH, standard bicarbonate, base excess and plasma concentrations of sodium, potassium, chloride, total protein, glucose, urea and creatinine. The final measurement was taken eight hours after the last dose of fluid and no food or water was offered to the horses during this time. Administration of the solution caused a rapid correction of the frusemide-induced dehydration and metabolic alkalosis. Absorption of the fluid from the gastrointestinal tract appeared to be very rapid because by 30 minutes after the last dose of the solution, plasma protein values were not significantly different from those before administration of frusemide. Plasma glucose concentrations became significantly increased for up to three hours after the fluid was given and an increase in creatinine and urea concentrations, which was observed after the administration of frusemide, was still evident at eight hours. The glucose-glycine-electrolyte solution was well retained, there being a mean bodyweight loss of 2.8 kg at three hours and 6.2 kg at eight hours after the last dose of fluid.

Animals↗
PubMed1986

Method of investigation of the accuracy of four digitally-displaying heart rate meters suitable for use in the exercising horse.

The measurement of heart rate during exercise in the horse has been recommended as a means of prescribing work effort, monitoring the changes in aerobic capacity during training and as part of the clinical examination of the performance horse. The accuracy of four heart rate meters (PEH 100, PU 10, HR 14 and HRM-7) was assessed by comparison with heart rate determined by simultaneous telemetry electrocardiography (ECG) using a rapid incremental exercise test on a treadmill. Heart rate displayed by all four meters showed significant correlations with the ECG heart rate, but only two meters (PEH 100 and HRM-7) had correlation coefficients of 0.98 or greater.

Animals↗
PubMed1986

Effects of training on muscle composition in horses.

Biopsy samples were obtained from the middle gluteal muscle of 10 Thoroughbred horses undergoing a commercial race-training program. Samples were obtained before the program began and again after 6 and 12 weeks of training. All horses had raced at least once by the 12th week of training. Serial sections of muscle were examined histochemically for myosin adenosinetriphosphatase after either acid (pH 4.3 and 4.6) or alkaline (pH 10.3) preincubation, and then muscle fibers were identified as types I, IIA, IIB, or IIC. The oxidative capacity of individual fibers was assessed, using the reduced nicotinamide dinucleotide tetrazolium-reductase stain, and the number of intermyofibrillar capillaries adjacent to each fiber were counted after staining, using the alpha-amylase-periodic acid-Schiff technique. Biochemical analyses involved the fluorometric measurement of 3 enzymes--citrate synthase, 3-hydroxy-acyl coenzyme A dehydrogenase, and lactate dehydrogenase--as markers of end terminal oxidative, beta-oxidative, and glycolytic potentials, respectively. Changes in fiber-type percentages did not occur in response to training. There was a significant (P less than 0.01) increase in the percentage of type IIB fibers, having high nicotinamide dinucleotide-tetrazolium reductase staining after 12 weeks of training. Alterations in the number of capillaries adjacent to each fiber type did not occur during the training period. There were increases in the activities of both citrate synthase and 3-hydroxy-acyl coenzyme A dehydrogenase after 6 weeks (P less than 0.05) and 12 weeks (P less than 0.001) of training. Alterations in the activity of lactate dehydrogenase did not occur in response to training.

Animals↗
PubMed1985

Hematologic responses to exercise and training.

Hematology has been widely used in attempts to provide information about disease states, performance problems, and fitness in performance horses. However, owing to factors such as the temperament of the horse and time of collection and feeding, considerable variation in the hemograms can be found. This article reviews some of the hematologic responses to exercise and training.

Animals↗
PubMed1985

Selection of an aminoglycoside antibiotic for administration to horses.

The serum concentrations of the aminoglycosides neomycin, kanamycin and streptomycin were determined after intravenous (iv) and intramuscular (im) administration. These values were then related to the minimum inhibitory concentrations (MIC) of a number of equine pathogenic bacteria to determine the duration of therapeutic serum concentrations of the aminoglycosides in the horse. Pharmacokinetic analysis of the data using neomycin as the example revealed a mean (+/- sd) peak serum concentration of 23.2 +/- 10.2 micrograms/ml present at 30 mins, and at 8 h the serum concentration was 2.8 +/- 0.8 micrograms/ml. From the pharmacological analysis of concentration-time data it was shown that neomycin was very rapidly absorbed from the im injection site, with an absorption half-time of 0.16 +/- 0.05 and was well absorbed (systemic availability was 73.7 +/- 26.9 per cent). A peak tissue level, which represented 40 per cent of the amount of drug in the body, was obtained at 32 mins after injection of the drug. At 8 h, the fractions of the dose in the central and peripheral compartments of the model were 1.5 per cent and 2.5 per cent respectively, and 96 per cent was the cumulative amount eliminated up to that time. Based on the MIC values of the majority of isolates of Corynebacterium equi, and only a few isolates of Klebsiella pneumoniae, Escherichia coli, Salmonella typhimurium and Streptococcus equi, one would expect a serum concentration of more than 2 micrograms neomycin/ml up to 8 h following im dosage (10 mg/kg) to be therapeutically effective.

Aminoglycosides↗