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Biomedical subjects

C Richardson

Publications and source records attributed to C Richardson.

At least 181 records · Page 10Linked to original sources

Bovine virus diarrhoea-mucosal disease virus: pathogenicity for the fetal calf following maternal infection.

Fifteen pregnant, bovine virus diarrhoea-mucosal disease (BVD-MD) antibody-free Jersey heifers were infected experimentally with a mixture of 10 cytopathic strains of BVD-MD virus isolated from cattle in Britain. Each cow was inoculated intramuscularly on gestation day 100 with a high or a low dose of virus grown in primary calf testis tissue cultures. None of the cows showed clinical signs of illness following exposure, but all had seroconverted within six weeks. Six fetuses, including one set of twins, died in utero following infection. Of these five were aborted between days 136 and 154; the sixth one was mummified and still retained at day 300. The remaining 10 fetuses survived to term, but all showed evidence of intrauterine growth retardation with or without gross malformation and/or dysmyelination of the central nervous system. Three were clinically affected with congenital nervous disease. Of the 10 liveborn fetuses, two had specific serum antibodies to BVD-MD. Non-cytopathic BVD-MD virus was recovered from all of the remaining eight. When non-immune cows become infected with BVD-MD virus in mid gestation: transplacental infection of the fetus will probably result; apart from the risk of fetal death, with or without abortion, there is a high probability of fetal mal-development which may not always be clinically obvious; the immunological competence of the fetus may be impaired; congenital infection is likely in a substantial proportion of liveborn calves. About one in 16 bovine fetuses in British herds are estimated to be at risk from BVD-MD virus infection.

Abortion, Veterinary↗

Border disease: a sequential study of surviving lambs and an assessment of its effect on profitability.

Pregnant Dorset horn gimmers inoculated with a non-cytopathic strain of the border disease virus produced "hairy shaker" lambs that were individually affected to a varying degree. Surviving lambs were observed for a period of up to 20 weeks when neurological signs were seen to gradually disappear. During this time live virus was isolated from a wide variety of sites in nearly all of the infected lambs. The infected animals grew at a significantly slower rate compared with the controls, particularly during the first 15 weeks. Several morphological defects are described the most consistent being the decreased weight of the central nervous system. By 20 weeks body-weights were about 20 per cent lower and carcase quality scores were reduced. An assessment is made of the economic losses attributable to BD taking into consideration carcase quality at 20 weeks and the perinatal losses.

Animals↗

The complete amino acid sequence of the alpha-subunit of pea lectin, Pisum sativum.

The complete primary structure of the alpha-subunit of the lectin from the pea (Pisum sativum) has been determined using a combination of tryptic and staphylococcal protease digestion, purification using Sephadex gel filtration and high-voltage electrophoresis followed by either manual or automated Edman degradation. The molecular weight of the alpha-subunit from sequence data and gel filtration in guanidine-HCl is close to 5800, which is lower than that determined by sedimentation equilibrium techniques. The sequence reveals considerable homology to concanavalin A and near identity to the alpha-subunit of the lentil lectin (Lens culenaris). As in the case of the lentil alpha-subunit, the alpha-methyl glucose binding site(s) are not present in this region, nor are the S1 and S2 metal ion binding sites as judged by homology consideration, though the residues for the S3 lanthanide binding (Glu 87 and Asp 136) are conserved from the available data on the alpha- and beta-subunits. Preliminary metal exchange experimens on the intact pea lectin indicate some differnces in the metal exchange properties of this lectin compared to concanavalin A, and therefore possible ligand variations in this region of the beta-subunit.

Amino Acid Sequence↗

Interpretation of lung function tests in the sickle-cell haemoglobinopathies.

Prediction equations have been evolved for the assessment of vital capacity, total lung capacity, and the single breath carbon monoxide transfer factor in haemoglobin SS and haemoglobin SC disease. These relationships take account of the growth disorder and anaemia in the sickle-cell states. The results suggest that, in the clinically stable state, any effects of alveolar capillary sickling and haemoconcentration and any altered reactivity of haemoglobins S and C with the test gas are of no significance for clinical respiratory physiology. Sex differences in lung function appear independent of haemoglobin type.

Adult↗

Variations of the intraesophageal pressure with maturation in the postnatal piglet.

Variations in intraesophageal pressure (Pes) to 5-min exposures of 100% O2, 10% O2, and 6% CO2 were studied in successive days during the first 2 months of 8 piglets. Pressure measurements were integrated over time to obtain mean pressure changes for each minute. Initial exposure to 100% O2 decreased the mean pressure in all piglets followed by an increase over the next 4 test minutes. 5 of 8 piglets demonstrated maximum increases (25--55% above control) at 5 days and between 15 and 22 days; 3 piglets only at 5 days. Initial exposure to 10% O2 increased the pressure in all piglets followed by a decrease pressure (-10%) in the next 4 min when the piglets were less than 22 days, and an increase (15--70%) when above this age. Exposure to 6% CO2 increased the pressure throughout the 5-min test period with the maximum increase (140--160%) at the earliest ages tested of 5 days.

Age Factors↗

Estimation of the developmental age of the ovine fetus and lamb.

Fifty-six fetuses and 33 lambs were obtained from a flock of ewes at set gestational intervals between 50 to 180 days after conception. The fetuses and lambs were killed, disected and the sizes and weights of a wide range of skeletal and soft tissues were measured. Five morphological parameters emerged as most suitable for the determination of normal foetal developmental age. By plotting the mean value and ninety-five per cent tolerance limits, the rates of growth and the variability of each parameter were studied. Crown-anus length is useful for determining fetal developmental age from 50 to 100 days gestation; brain weight, long bone length and the number of appendicular ossification centres can be used to determine fetal development age from 50 days gestation until term.

Animals↗

Adrenal cyst.

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Adrenal Gland Diseases↗