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Biomedical subjects

G Houghton

Publications and source records attributed to G Houghton.

7 recordsLinked to original sources
PubMed1992

Assessing GP trainees.

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Education, Medical, Graduate↗
PubMed1986

Immunosuppression of carp (Cyprinus carpio L.) to ichthyophthiriasis using the corticosteroid triamcinolone acetonide.

The immune response of juvenile mirror carp (Cyprinus carpio L.) has been investigated in relation to protective immunity and immunosuppression to the disease ichthyophthiriasis. Protective immunity was induced by exposing juvenile carp to approximately 2,000 theronts per fish for 3 hours at a concentration of approximately 80 theronts cm-3 in dechlorinated water pH 7.0-7.2, 20 +/- 2 degrees C in the dark, on three separate occasions of 14 day intervals. Following each exposure, re-infection was prevented by transferring fish to clean aquaria twice daily from day 5-10. Fish were challenged 4 weeks following exposure to the third immunising infection with a potentially lethal dose of approximately 8,000 theronts per fish for 3 hours at a concentration of approximately 320 theronts cm-3. All immunised fish survived although 19% showed initial signs of invasion, the parasites in these instances being confined to periphery of fins. Mortalities of 100% were recorded in non-immunised controls, first deaths occurring 5 days after challenge. Fourteen days following challenge, immune fish received one of the following treatments; intraperitoneal injection of the corticosteroid triamcinolone acetonide at a dose of 200 micrograms g-1 body weight, intraperitoneal injection of 0.85% saline or left untreated; non-immunised fish were subjected to similar procedures. On challenge 6 days later, all fish developed heavy infection with up to 100% mortalities with the exception of immunised fish administered saline or left untreated. Repeat experiments gave comparable results. The results indicate that immunosuppression can be induced by administration of high levels of synthetic corticosteroid.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1975

Phospholipids and fat secretion by cows on normal and low fiber diets: lactational trends.

Daily yields of milk, milk fat, phospholipids, and fatty acids were measured weekly during lactations of two groups of cows on a normal and restricted roughage diet. Milk yield was higher in normal cows during the initial 15 wk of lactation. Fat production decreased and was consistently lower in milk from cows on restricted roughage (from 1.2 to .4 in normal and from .8 to .3 kg/day for restricted). Phospholipid secretion decreased from an average 7 g to 3 g/day in both groups. The concentration of phospholipid in both milks fluctuated during lactation (20 to 30 mg/100 ml milk), but in milks from restricted cows it tended to increase with progress of lactation. Milk lipids from cows on restricted diets had higher phospholipid to fat ratio, (1.0 to 1.5 compared to .5 to .6 g phospholipid/100 g fat for milk from normal cows). Composition of the phospholipid classes changed slightly during lactation. Phosplatidylinositol changed most, increasing from 4 to 10 and 6 to 8% in normal and restricted milks, respectively. Fatty acids of short and medium chain lengths (C6 to C14) followed a typical quadratic regression in normal milks increasing from 10 to 30% of the total fatty acids during the first 25 wk of lactation. In restricted milk these fatty acids were already high (25%) within 2 wk and followed a linear regression with lactation. Both palmitic and stearic acid were lower in milk from restricted cows while oleic and linoleic acid were higher particularly after 10 wk of lactation.

Animal Feed↗
PubMedDate not supplied

The cellular proliferative response, humoral antibody response, and cross reactivity studies of Tetrahymena pyriformis with Ichthyophthirius multifiliis in juvenile carp (Cyprinus carpio L.).

The immune response of 10-12-week-old juvenile carp to T. pyriformis [CCAP 1630/w, 1939 (w)] was investigated. The humoral antibody response following one and two intraperitoneal injections of whole live T. pyriformis (protein concentration of 25 micrograms/g body weight), separated by an interval of 4 weeks, was monitored over 12-16 weeks. Peak antibody titres were detected 6 weeks following antigen administration. Antibody titres were elevated following the second injection, and relatively high levels were still maintained by week 16. Proliferative responses measured by autoradiography following intraperitioneal injection of methyl 3H thymidine (1-2 microCi/g body weight) were recorded in the pronephros, opisthonephros, and spleen at weekly intervals for 4 weeks following each injection of T. pyriformis. Immunised fish had higher counts than nonimmunised controls, with the greatest counts occurring at 2 and/or 3 weeks following one injection of antigen and 2 weeks following two injections. Activity was recorded prior to peak antibody production with the pronephros and opisthonephros having greater proliferative responses than the spleen. Cross antigenicity studies to examine protection of carp against I. multifiliis following administration of T. pyriformis, showed little evidence in support of protection using this strain of T. pyriformis. Further, antisera raised in either carp, rabbits, or rats failed to show any cross antigenicity between these two species of protozoa.

Animals↗