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Biomedical subjects

I D Aitken

Publications and source records attributed to I D Aitken.

At least 19 recordsLinked to original sources
PubMed1992

The influence of dietary essential fatty acids on uterine C20 and C22 fatty acid composition.

The effect of dietary fatty acids on uterine fatty acid composition was studied in rats fed control diet or semi-synthetic diet supplemented with 1.5 microliter/g/day evening primrose oil (EPO) or fish oil (FO). Diet-related changes in uterine lipid were detected within 21 days. Changes of 2- to 20-fold were detected in the uterine n-6 and n-3 essential fatty acids (EFA) and in certain saturated and monounsaturated fatty acids. The FO diet was associated with higher uterine C20 and C22 n-3, and the EPO diet, with higher uterine n-6 fatty acid. High uterine C18:2 n-6 was detected in neutral lipid (NL) of rats fed high concentrations of this fatty acid, but there was little evidence of selective incorporation or retention of C18:2 n-6 by uterine NL. The incorporation of EFA into uterine phospholipids (PL) was greater than NL EFA incorporation, and uterine PL n-3/n-6 ratios showed greater diet dependence. Tissue/diet fatty acid ratios in NL and PL also indicated preferential incorporation/synthesis of C16:1 n-9, and C16:0, and there was greater incorporation of C12:0 and C14:0 into uteri of rats fed EPO and FO. Replacement of 50-60% of arachidonate with n-3 EFA in uterine PL may inhibit n-6 EFA metabolism necessary for uterine function at parturition.

Animals↗
PubMed1992

Developmental changes in the fatty acids of rat uterus and the influence of dietary essential fatty acids.

The effect of age on uterine fatty acid composition was studied in rats fed diets of differing fatty acid composition. Uteri of newly weaned 23-day rats had a higher fatty acid content and a higher proportion of short-chain (less than or equal to C18) fatty acids. Higher incorporation of C less than or equal to 18 fatty acids into neutral lipid (NL) and phospholipid (PL) of young 42-day rats compared with adult 240-day rats was detected. Uterine NL incorporated predominantly C less than or equal to 18 fatty acids which may be an important metabolic energy store in developing uterine tissue. Incorporation of C less than or equal to 18 fatty acids by uterine PL and NL was relatively unselective. In contrast, there was selective retention of arachidonic acid (AA) and docosahexanoic acid (DHA) throughout uterine development. An effect of dietary EFA on uterine n-3 and n-6 EFA was detected in each age group. There was marked retention of uterine AA when dietary supplies of n-6 EFA were low, but the total AA, eicosapentaenoic acid (EPA) and DHA in uterine PL remained constant in the three diet groups, and a constant content of AA, EPA and DHA was maintained throughout uterine development, regardless of diet. The degree of n-3 substitution achieved in this study inhibited uterine release of PG and parturition in adult rats.

Aging↗
PubMed1989

Clinical aspects and prevention of Q fever in animals.

The natural reservoir of Coxiella burnetii encompasses many free-living vertebrates but the major risk of human infection arises through contact with infected ruminant livestock and their contaminated products. The organism has a remarkable affinity for the ruminant placenta and mammary gland but the great majority of naturally-occurring infections are asymptomatic. However, the potential of C. burnetii to cause abortion has been demonstrated experimentally and observed in the field while more recent evidence has implied a contributory role in bovine infertility. Empirical vaccines incorporating inactivated whole cells of C. burnetii or derivatives have induced varying degrees of protection of cattle and sheep against both natural and experimental challenge but, in some cases, severe reactions have occurred at inoculation sites. Modifications in processes of antigen preparation seem to overcome this problem. Discrimination between antibodies resulting from natural infection and those induced by vaccination is possible using ELISAs with specificity for individual immunoglobulin isotypes.

Abortion, Septic↗
PubMed1989

The effect of chlamydial infection on the initiation of premature labour: serial measurements of intrauterine prostaglandin E2 in amniotic fluid, allantoic fluid and utero-ovarian vein, using catheterised sheep experimentally infected with an ovine abortion strain of Chlamydia psittaci.

The initiation of premature labour by an ovine abortion strain of Chlamydia psittaci was studied in relation to Prostaglandin E2 (PGE2), which plays a major role in parturition. The local intrauterine concentration of PGE2 was monitored after experimental infection with C. psittaci, during late gestation, using a catheterised sheep model. Indwelling catheters were implanted into the amniotic and allantoic cavities of six control sheep, and into six sheep infected with an ovine abortion of C. psittaci. The release of PGE2 into the utero-ovarian vein of these sheep was also monitored. Infection with C. psittaci was associated with a premature rise in PGE2 in the amniotic fluid between days 122 and 135 of gestation (P less than 0.01). A premature increase in PGE2 was defected between days 127 and 136 of gestation (P less than 0.05) in the allantoic fluid of sheep infected with C. psittaci, but not in the control uninfected sheep. Chlamydial infection significantly decreased the secretion of PGE2 into the utero-ovarian vein. The mean concentration of PGE2 in the utero-ovarian vein of infected sheep was 68.8 +/- 5.2% of the PGE2 concentration of control sheep between days 122 to 141 of gestation (P less than 0.01). The release of PGE2 into the utero-ovarian vein increased between days 126 to 136 of gestation in infected and control sheep (P less than 0.01). The results from the catheterised sheep model indicated that C. psittaci infection is associated with a local intrauterine release of PGE2. The magnitude of this release was similar to the PGE2 release in control sheep prior to parturition.(ABSTRACT TRUNCATED AT 250 WORDS)

Allantoin↗
PubMed1987

Q fever in the United Kingdom and Ireland.

In Britain, Q fever in man was first reported in 1949. Two years later a serological survey of cattle revealed a prevalence of infection of 2.1%. In the 1970's prevalences of 4.5% and 3.1% were encountered respectively in cows that had aborted or calved normally in central England. In sheep, antibodies to C. burnetii have been detected in approximately 2.8% of sera examined for diagnostic purposes and 0.6% of sheep awaiting export. Since 1975 fewer than 10 incidents of C. burnetii associated disease in cattle have been reported annually while the figure for sheep has been even smaller. Between 100 and 200 cases of human Q fever are encountered annually. The majority are sporadic but occasionally large outbreaks occur. Direct contact with farm livestock or other animals cannot always be established. Despite Public Health interest in Q fever the low economic significance of C. burnetii infection of farm livestock limits opportunities for conjoint medical-veterinary epidemiological investigations. In Ireland, the patterns of animal infection with C. burnetii and of human Q fever are broadly similar to those in Britain.

Animals↗
PubMed1985

Attempted venereal transmission of Chlamydia psittaci in sheep.

Attempts were made to transmit Chlamydia psittaci, the causal agent of enzootic abortion of ewes, in three different ways. Ten ewes were inseminated artificially with freshly collected semen containing 10(5) CELD50 chlamydia. Serological evidence of infection was found two weeks before parturition in nine ewes and the organism was recovered from three of them. By six weeks post partum antibody titres had fallen and were negative in six ewes. Twenty-four hours after service two groups of 10 ewes were infected intravaginally with 10(8) CELD50 and 10(3) CELD50 chlamydia respectively. Positive complement fixation titres were present in the first half of pregnancy in all the ewes in the high dose group but not the low dose group. None of the ewes showed evidence of infection at parturition. Fourteen ewes were served by four rams which had been intravenously infected with 10(8) CELD50 chlamydia four to six days earlier. Following service seroconversion occurred but titres became negative again by late pregnancy. No microbiological evidence of infection was detected in any of the ewes at parturition but complement fixation titres were positive in 12 of 14 ewes sampled six weeks post partum. The 14 ewes were sampled during their pregnancies the next year and none showed any evidence of chlamydial infection. It is concluded that venereal transmission of C psittaci is biologically feasible in sheep, but that under normal systems of flock management in Britain it is unlikely to contribute greatly to the epidemiology of enzootic abortion of ewes.

Abortion, Septic↗
PubMed1985

The tonsillar carriage of Pasteurella haemolytica in lambs.

To study colonization of the tonsils by Pasteurella haemolytica, attempts were made to isolate the organism from the tonsils of lambs which died or were killed in the course of unrelated experiments. In addition, repeated tonsillar swabs were taken from 37 lambs and their 28 dams over a 3-month period. From lambs under 3 days old, only A serotypes and untypable strains of P. haemolytica were recovered, while T serotypes were first detected in 3-week-old lambs. As the age of the lambs increased, the fall in the isolation rate of A serotypes and of untypable strains was accompanied by an increase in T serotype isolation. In lambs 9 to 12 weeks old, over 80 per cent of isolates were T serotypes. Of the 222 swabs from live lambs, 88 (40 per cent) yielded P. haemolytica, with more than one serotype being recovered from 24 of the 88 positive swabs. Multiple isolations, mostly of 2 serotypes, were made from lambs of all ages but were commonest at 12 weeks of age. Of the 117 isolates, 70 (60 per cent) were of biotype T, 31 (26 per cent) were of biotype A and 16 (14 per cent) were untypable. P. haemolytica was isolated from 25 of the 28 ewes on 1 to 5 of the 6 sampling occasions. The 65 positive swabs yielded 81 T serotypes (78 per cent), 21 A serotypes (20 per cent) and one untypable strain as 32 single and 33 multiple isolations. The typed isolates comprised 7 A serotypes and 3 T serotypes. Only one serotype (A6) isolated from lambs was not recovered from ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Comparison of Chlamydia psittaci isolates by DNA restriction endonuclease analysis.

Preparations of DNA from 12 Chlamydia psittaci isolates and one Chlamydia trachomatis strain were compared by restriction endonuclease analysis. Polyacrylamide gel electrophoresis, followed by silver staining, resulted in optimal resolution of fragments generated by digestion. By this technique, four distinct electropherotypes were demonstrated when ovine abortion, ovine arthritis, and avian and Cal10 strains of C. psittaci were examined. Minor profile differences allowed the discrimination of avian isolates derived from psittacine and columbiforme species, and the Cal10 DNA electropherotype was shown to have features in common with these profiles. However, there were no detectable differences in the DNA patterns of eight ovine abortion isolates.

Abortion, Septic↗
PubMed1984

Promotion of Pasteurella haemolytica infection in mice by iron.

Mice given 60 micrograms iron, as aqueous ferric ammonium citrate, intravenously were more susceptible than untreated controls to intraperitoneal infection with T serotypes of Pasteurella haemolytica as shown by significant reductions in LD50 values. Iron injection has advantages over administration of bacteria suspended in mucin for studies of P haemolytica infection in mice.

Animals↗
PubMed1978

Immunocompetent cells in avian paraocular glands.

A study was made of the Harderian and lachrymal glands of fowls, pheasants, turkeys and pigeons. Accumulation of heterophils and plasma cells commenced soon after hatching, was well advanced by four weeks of age and was always greater in the Harderian than in the lachrymal glands. Plasmablasts entered via interlobular capillaries, maturing as they migrated to and congregated round the lobular collecting ducts. Their secreted immunoglobulin was readily demonstrated in the duct lumen. Russell body containing cells of diverse morphology were a consistent feature of infiltrated Harderian glands. Though scant in the glands proper, lymphoid tissue was abundant in the walls of their draining ducts.

Animals↗
PubMed1977

Plasma cells in vertebrate paraocular glands.

The Harderian and lachrymal glands of eight mammals and two reptiles were examined histologically for plasma cells and the extent of infiltration compared to that in the Harderian gland of the fowl. Moderate accumulations were observed in one or both glands of the goat, sheep, cow, horse, dog and pig, but only few cells were present in the glands of the mouse and rabbit. No plasma cells were encountered in snake glands but some were detected in both glands of lizards. It is suggested that glandular secretions contribute to local immunity.

Animals↗
PubMed1977

Further observations on functional deletion of paraocular glands in the fowl (Gallus domesticus).

Methods are described for inoculation of the fowl Harderian gland with sclerosing reagent and for its surgical excision. Though very destructive the former procedure proved the less reliable in achieving the gland's complete functional deletion. Three weeks after surgical removal of the Harderian glands the lachrymal glands of 10-week-old fowls were heavier and contained more immunocompetent cells than the glands of intact and sham operated birds. When adult birds deprived of both paraocular glands were given sheep erythrocytes or Newcastle disease virus by eye drop they developed slightly higher than normal titres of serum antibody but failed to produce lachrymal antibody.

Animals↗
PubMed1977

Removal of the lachrymal gland and ligation of the Harderian gland duct in the fowl (Gallus domesticus): procedures and sequelae.

Surgical methods are described for removal of the lachrymal gland and ligation of the Harderian gland duct in the fowl. Total or partial cystic degeneration of the Harderian gland and loss of immunoglobulins from lachrymal fluid was evident in three of six adult birds 10 weeks after operation. Functional deletion of these paraocular glands is thus feasible and can be used for investigations of local immunity of the oculonasal region.

Animals↗
PubMed1976

Local immunity in the respiratory tract of the chicken. I. Transudation of circulating antibody in normal and virus-infected birds.

Three-week-old chickens were given sheep erythrocytes or bovine serum albumin intravenously. Seven days later their tears and saliva possessed low levels of antibody to those antigens. Concurrent infection with lentogenic Newcastle disease virus (NDV) caused a significant increase in transuded antibody in those fluids. In chickens with circulating antibody to NDV, induced by parenterally administered inactivated vaccine, respiratory infection with heterologous infectious bronchitis virus resulted in limited transudation of anti-NDV. In contrast, the tears, saliva and tracheal fluid of non-vaccinated chickens undergoing primary infection with NDV acquired considerable levels of specific anti-NDV. The difference between the two groups is attributed to locally synthesized antibody.

Animals↗