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Biomedical subjects

F Jackson

Publications and source records attributed to F Jackson.

At least 145 records · Page 8Linked to original sources
PubMed1983

Development of morphological changes in the small intestine of lambs continuously infected with Trichostrongylus vitrinus.

Groups of three-month-old worm-free Suffolk cross lambs were given 2500 Trichostrongylus vitrinus larvae on five days each week for four, six, eight and 13 weeks and killed one week later. Severe villous atrophy, epithelial erosion and cellular infiltration were common features in the duodenum and the following 2 to 3 m of intestine of lambs killed at weeks 5 and 7. There was evidence of intestinal recovery in the lambs killed at weeks 9 and 14; five of the seven lambs had large areas of intestine which appeared relatively normal and worm activity appeared to be confined largely within focal areas ("fingerprint lesions'). There was no change in the linear distribution of the worms in the intestine over the course of the experiment. The highest percentage of the larval challenge was recovered from lambs killed at week 5 and worm burdens were not cumulative. Lambs killed at week 14 were resistant to larval reinfection.

Animals↗
PubMed1982

Changes in the flow and composition of gastric lymph in sheep given a primary infection of 10,000 Haemonchus contortus.

Some aspects of the local immune response to a primary infection with 10,000 Haemonchus contortus were studied in five sheep by monitoring changes in the flow and composition of gastric lymph continuously sampled for up to 34 days from the start of infection. Increases in lymph flow rates were recorded in four animals at varying times after the start of infection. These were usually associated with an increase in the protein content of the lymph and were considered to be a consequence of inflammatory reactions in the abomasum. Apart from a small increase in lymphocyte traffic no changes which could be attributed to a local immune responses were observed in the lymph. It is suggested that the chronic nature of infections like haemonchosis is possibly because the worms can parasitise the gut without stimulating a vigorous local immune response.

Albumins↗
PubMed1982

Attempts to immunise sheep against Ostertagia circumcincta with irradiated larvae.

Mature sheep immunised with two doses of 10,000 irradiated Ostertagia circumcincta larvae were only slightly resistant to challenge with a single dose of 10,000 larvae. This slight resistance was abolished if the 'vaccine' worm population was removed one week before challenge. In contrast, seven of eight sheep immunised with irradiated Haemonchus contortus larvae were highly resistant to homologous challenge. Evidence of some cross protection against challenge with O circumcinta was observed in five of six sheep immunised with irradiated H contortus in that egg counts were lower and more worms were retarded as fourth stage larvae.

Animals↗
PubMed1982

Specific identification of strongyle eggs in small samples of sheep faeces.

A method for the specific identification of strongyle eggs in small samples of sheep faeces based on dimensional and biological characteristics is described. More than 90 per cent of the eggs of Ostertagia spp and of Trichostrongylus vitrinus can be positively identified. For other species supporting information from larval cultures may be needed but this need will vary according to the composition of the sample.

Animals↗
PubMed1981

Explant culture of rat esophagus in a chemically defined medium.

Esophagus from adult male CDF rats was cultured for a period of 28 d in CMRL-1066 medium supplemented with pyruvic acid, HEPES buffer, beta-retinyl acetate, and antibiotics. Morphological, radioautographic, and biochemical studies indicated that the survival of the tissue in serum-free medium was equivalent to that in medium containing 5% heat-inactivated fetal bovine serum. There was a relatively constant uptake of [3H]thymidine into DNA and [3H]leucine into protein of the esophageal explants during the incubation. Only the basal cells of the epithelium incorporated [3H]thymidine into their nuclei. The normal morphology of the tissue was preserved when the explants were maintained at both 37 and 30 degrees C, and in either 50 or 20 % 02. Ninety-five percent O2 was highly toxic to the cells of the explants. This culture system should be suitable for a variety of investigations in esophageal cell differentiation and carcinogenesis.

Animals↗
PubMed1979

Species specific grass pollen sensitivity: diagnosis and treatment with single grass species Allpyral vaccines.

Skin test titrations and nasal provocation tests in sixty patients with hay fever showed specific reactions to extracts of individual grass species. There was, however, no correlation between skin and nasal sensitivity. Repeat testing after treatment with Allpyral vaccines consisting of only the grass species to which the nasal reaction was most severe, or only one of several pollens to which reactions were equally severe, showed marked diminution of skin and nasal sensitivity not only to the single pollen used for immuno-therapy but to all five common pollens used in the Allpyral grass mix. Clinical results seemed much improved as compared with results in the same year for Allpyral five grass mix vaccines, especially in the case of patients treated with Timothy, rye, or cocksfoot. It was concluded that these three grassees were to be preferred for treatment in England, and that these grasses contain common allergens.

Dose-Response Relationship, Immunologic↗
PubMed1979

Observations on the egg output resulting from continuous low level infections with Ostertagia circumcincta in lambs.

Faecal egg counts were determined twice weekly for two groups of four-month-old worm free cross Suffolk lambs experimentally infected with 100 and 320 Ostertagia circumcincta larvae, five times per week for 20 weeks. The group mean egg count in both groups rose to a maximum of approximately 500 eggs per gram during weeks 12 to 14 and had fallen to less than half of that value at slaughter. There was no statistical difference in egg output between these two groups or between them and a comparable group of lambs receiving 4000 Ostertagia circumcincta larvae per day. No significant changes in live weight gain or serum pepsinogen levels were observed in the lambs given 100 and 320 larvae per day.

Animals↗
PubMed1978

Explant culture of rat colon: a model system for studying metabolism of chemical carcinogens.

An explant culture system has been developed for the long-term maintenance of colonic tissue from the rat. Explants of 1 cm2 in size were placed in tissue-culture dishes to which was added 2 ml of CMRL-1066 medium supplemented with glucose, hydrocortisone, beta-retinyl acetate, and either 2.5% bovine albumin or 5% fetal bovine serum. The dishes were placed in a controlled-atmosphere chamber which was gassed with 95% O2 and 5% CO2. The chamber then was placed on a rocker platform which rocked at 10 cycles per min causing the medium to flow intermittently over the epithelial surface. The explants were incubated at 30 degrees C. The viability of the tissue was measured both by incorporation of specific precursors into cellular macromolecules and by monitoring of tissue morphology with light and electron microscopy. Cultured rat colon was able to metabolize benzo[alpha]pyrene, 7,12-dimethylbenz[alpha]anthracene, aflatoxin B1, dimethylnitrosamine, 1,2-dimethylhydrazine, and methylazoxymethanol acetate into chemical species that bind to cellular DNA and protein.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1977

Pulmonary oedema.

Explore the source record for details and available documents.

Acute Disease↗
PubMed1976

Binding of (3H)benzo(a)pyrene to DNA in cultured human bronchus.

The studies reported here demonstrate some of the factors affecting the binding of benzo(a)pyrene (BP) to macromolecules in cultured human bronchial mucosa. Bronchial specimens were obtained at either surgy or "immediate" autopsy from patients with and without lung cancer. Grossly normal-appearing pieces of bronchus were cultured in a chemically defined medium, i.e., CMRL 1066 medium containing 1 mug insulin per ml, 0.1 mug beta-retinyl acetate per ml,, 0.1 mug hydrocortisone hemisuccinate per ml, 2 mM L-glutamine, 100 units penicillin G per ml, and 100 mug streptomycin per ml. After 7 days, explant cultures were exposed to [3H]BP, usually for 24 hr, and then binding to total cellular macromolecules was studied by autoradiography, and binding to DNA was measured following isolation of DNA from bronchial mucosal cells. The extent of binding of [3H]BP was dependent on dose of BP, length of exposure to [3H]BP, and temperature. By autoradiography, bronchial epithelial cells bound more [3H]BP than stromal fibroblasts. Both 7,8-benzoflavone and butylated hydroxytoluene appeared to reduce the level of [3H]BP bound to DNA, while nicotine apparently did not alter the level of binding. These studies demonstrate that the bronchial mucosa, an important human cancer target tissue, has the capability to form metabolites of BP which bind to macromolecules including DNA. In addition, 7,8-benzoflavone and butylated hydroxytoluene, both known to alter the microsomal metabolism of BP, reduce the level of [3H]BP bound to DNA.

Benzopyrenes↗