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Biomedical subjects

K L Morgan

Publications and source records attributed to K L Morgan.

At least 109 records · Page 6Linked to original sources
PubMed1989

Circulating lymphocytes, neutrophils and immune complexes in pigs after feeding.

There are reports in the literature claiming that pigs experience a lymphopenia after feeding. This is not observed in other species. We set out to investigate this phenomenon because of the unusual route of lymphocyte recirculation in pigs. for it suggested that this might be a specific response to dietary antigens. We were unable to confirm this phenomenon. A lymphopenia was observed in both test and control groups as a non-specific response to restraint and blood sampling. In contrast, feeding was associated with a significant neutrophilia (mean 58%, P less than 0.002). There were no increases in circulating IgA, IgG or IgM immune complexes after feeding but IgG immune complexes remained at a higher level than in the control group.

Animals↗
PubMed1989

Effect of active immunization against oxytocin on gonadotrophin secretion and the establishment of pregnancy in the ewe.

A group of 14 ewes was actively immunized against oxytocin coupled to carrier protein, and comparisons of the reproductive status of these animals were made against ewes immunized against carrier protein only (N = 5) and untreated controls (N = 6). The last two groups were indistinguishable and were therefore combined as a single control group for analysis of the results. Oestrous cycle lengths were significantly extended in oxytocin-immunized ewes (P less than 0.005) with 42% of cycles lasting greater than 18 days. Cloprostenol treatment in the mid-luteal phase resulted in apparently normal luteal regression and re-ovulation, but luteal phase FSH concentrations and follicular phase LH concentrations were elevated in the immunized ewes, although surge levels of both hormones were unaffected. Measurements of free oxytocin concentrations in the blood suggested that these were significantly raised in treated animals. Progesterone concentrations in peripheral plasma were not altered by treatment. Mating resulted in a conception rate of 91% in control ewes compared with only 28% in oxytocin-immunized animals (P less than 0.01). There was no evidence of any conceptus material in the uteri of non-pregnant immunized ewes 25 days after service. Some had re-ovulated, whereas the ovaries of others contained mature corpora lutea which had been maintained. Ovarian histology appeared normal. We conclude that active immunization against oxytocin influences gonadotrophin secretion and reduces fertility. The site(s) of action for both of these effects needs to be determined.

Animals↗
PubMed1988

131I in the thyroid glands of sheep from Wales and south-west England after the Chernobyl accident.

Radioactive material from the Chernobyl reactor was deposited over the United Kingdom between May 2 and May 4, 1986. In this report, the 131I content of ovine thyroid glands, collected from seven abattoirs in Wales and south-west England is used to monitor the geographical distribution of the contamination. The results indicate that there was considerable local variation in the degree of contamination and suggest that, in addition to the major areas of contamination, deposition of high levels of radioactive material also occurred in isolated areas in the south-west of England. These observations confirm the value of monitoring 131I in the thyroid glands of grazing ruminants as a sensitive index of environmental contamination with the products of nuclear fission.

Abattoirs↗
PubMed1987

Prevalence of chlamydia, toxoplasma, toxocara and ringworm in farm cats in south-west England.

The prevalence of infection with Chlamydia psittaci, Toxoplasma gondii, Toxocara cati and Microsporum canis was examined in 51 cats on 22 sheep farms in the Bristol area. Serum antibody to C psittaci and T gondii was present in 45 per cent and 47 per cent of cats, respectively. At the time of sampling C psittaci was isolated from 6 per cent of the cats, T cati was identified in 63 per cent of faecal samples but neither T gondii nor M canis was isolated. When examined according to the farm of origin, 22.7 per cent of farms had cat populations with no evidence of infection with C psittaci or T gondii. Of the remainder, 45.5 per cent supported cat populations with evidence of both infections and 31.8 per cent had evidence of T gondii infection alone. None of the farms had cat populations with evidence of C psittaci infection alone. Two of the cats infected with C psittaci were excreting viable organisms in the faeces. The possible significance of this to the epidemiology of ovine enzootic abortion is discussed.

Animals↗
PubMed1987

Injection site reactions and antibody responses in sheep and goats after the use of multivalent clostridial vaccines.

Uncertainty concerning the use, efficacy and possible adverse effects of clostridial vaccination in goats prompted a study of the injection site reactions and antibody responses in 40 goats and 40 sheep. The vaccines used were Covexin 8, Heptavac and Tasvax 8. In all the animals swellings averaging 2.5 cm in diameter were present at the injection site seven days after vaccination and were still apparent 28 days after vaccination. The injection site reactions could not be attributed to faulty vaccination technique because they did not occur in a control group injected with sterile water. By 14 days the reactions were significantly larger in sheep than in goats and by 28 days the reactions to Covexin 8 were larger than those to the other vaccines in sheep and goats. Serum antibody was present in all groups before vaccination and, with the exception of the goats vaccinated with Heptavac, increased 14 days after vaccination. The increase was greater in sheep than in goats. By 28 days antibody levels had declined in all but the sheep vaccinated with Heptavac in which a further increase occurred. At that time, the antibody levels in vaccinated sheep were still higher than in the unvaccinated sheep whereas the antibody levels in vaccinated goats were no longer different from those in the control goats. These results suggest that there is a difference between the vaccines used and between the responses of the two species and support the clinical observation that the protection afforded to goats by multivalent clostridial vaccines is poorer than that afforded to sheep.

Animals↗
PubMed1987

Antibodies to food and environmental antigens in serum, respiratory tract and intestine of pigs.

Serum antibodies to food, bedding and dust were detected in pigs by precipitation and ELISA. There was an age-related decrease in the number of animals with precipitating antibodies and in the specific activity of IgG and IgM antibodies. Antibodies to food, bedding and dust were detected in respiratory and intestinal secretions, but there were differences in the distribution and isotype of antibodies to these three antigens.

Age Factors↗
PubMed1980

Immunoglobulin levels in porcine nasal and tracheal secretions--the influence of the method of collection.

Lavage and tampons were assessed, as methods of obtaining respiratory tract secretions, by comparing the immunoglobulin content of porcine nasal and tracheal secretions collected by both methods. The IgA: IgG ratio was lower in secretions collected on tampons than in those collected from a corresponding region of the tract by lavage. It is suggested that this difference was the result of epithelial damage caused by the tampon and leakage of serum proteins into the secretion. Lavage was adopted as the most suitable method of collecting respiratory tract secretions. There was no significant difference (P > 0.1) between the IgA: IgG ratio in nasal and tracheal secretions collected by this method.U

Animals↗
PubMed1980

Quantification and origin of the immunoglobulins in porcine respiratory tract secretions.

The immunoglobulin content of porcine nasal, tracheal and bronchio-alveolar secretions was determined. IgA was the predominant immunoglobulin in nasal and tracheal secretions, there being no significant difference (P greater than 0.01) between their IgA:IgG ratios of 2.7:1 and 2.4:1, respectively. In contrast, IgG was the predominant immunoglobulin in bronchioalveolar secretions, the IgA:IgG ratio being 0.7:1. The ability of tracheal and lung tissue to synthesize IgA and IgG was determined in vitro. Tracheal cultures synthesized more IgA than IgG whereas in the lungs the reverse occurred, the ratio of IgA:IgG synthesis being 1.4:1 and 0.4:1, respectively. The proportion of serum-derived IgA and IgG in respiratory tract secretions was determined by measuring the transfer of 125I- and 131I-labelled immunoglobulins from serum. It appeared that more than 97% of the IgA was produced locally. More significantly a proportion of the IgG was also synthesized locally. This proportion was smallest in nasal secretions (21.8%) and greatest in bronchio-alveolar secretions (62.6%). The results suggest that IgG, a large proportion of which is locally synthesized, is important in the homeostatic mechanisms of the lower respiratory tract.

Animals↗