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Biomedical subjects

E Jackson

Publications and source records attributed to E Jackson.

At least 109 records · Page 6Linked to original sources
PubMed1984

Resistance to Haemonchus contortus transferred between genetically histocompatible sheep by immune lymphocytes.

The pattern of faecal egg counts after infection with 10,000 Haemonchus contortus larvae was similar within but not between, four pairs of monozygous twin sheep. Transfer of whole lymph or washed lymph cells from three immune donor sheep to their identical co-twin recipients reduced the susceptibility of the recipients to challenge with 10,000 larvae as measured by faecal egg counts. Cells from a nonimmune donor did not have this effect. In a final experiment, washed cells from an immune triplet sheep, which was actively responding to a repeated challenge infection, transferred a secondary local IgA response to a second recipient triplet and resulted in a marked reduction in worm count when compared with that of a third infectivity control triplet.

Animals↗
PubMed1983

Studies on the local immune response of the lactating ewe infected with Ostertagia circumcincta.

Changes in the flow and composition of gastric lymph were monitored in groups of lactating and non-lactating ewes which were repeatedly infected with Ostertagia circumcincta. As judged by faecal egg counts and worm burdens the lactating group was more susceptible than the non-lactating controls to the challenge infection. Increased amounts of pepsinogen as well as larger numbers of eosinophils and neutrophils entering the gastric lymph indicated considerable abomasal damage and inflammation in the lactating ewes. However, measurement of the flow of lymphocytes as well as the amount of IgA and IgA antibody in the lymph did not indicate that these aspects of the local immune response were impaired during lactation; in fact the output of IgA-containing lymphocytes as well as IgA itself was usually raised in the lactating sheep. Lymph flow was increased and lymph globulin concentrations proportionally decreased in lactating ewes, irrespectively of whether they were infected with worms. It is suggested that these changes were caused by the increase in voluntary food intake which occurs during lactation.

Animals↗
PubMed1983

Local immunity and Ostertagia circumcincta: changes in the gastric lymph of sheep after a primary infection.

Some aspects of the kinetics of the primary local immune response to O. circumcincta were studied by monitoring the flow and composition of gastric lymph from 4 sheep for 3 weeks after infection with 50 000 larvae. A significant increase in the frequency of lymphoblasts in the lymph showed that all the sheep were responding immunologically to the parasites from day 8 onwards. However, considerable individual variation in degree and timing was evident in other aspects of the immune response; 2 animals responded with large increases in lymphocyte output which reached a peak on day 5 or day 10, whereas the main response in the other 2 sheep appeared to be inflammatory in nature, with large increases in lymph flow and eosinophil output which occurred during the third week of infection. No significant changes in the content of IgA or IgA anti-worm antibody were detected in the lymph, but pepsinogen concentrations were significantly raised from day 12 onwards.

Animals↗
PubMed1983

Local immunity and Ostertagia circumcincta: changes in the gastric lymph of immune sheep after a challenge infection.

Immunity to Ostertagia circumcincta was demonstrated in 5 previously infected sheep which were killed 10 days after challenge with 50 000 larvae. This immunity was expressed as a reduction in the number as well as the degree of development of the surviving parasites compared with those found in 6 control sheep. Gastric lymph was sampled from the immune group from 2 days before till 10 days after challenge and a secondary local immune response was detected. The main features of this response were a large increase in cell output in the lymph, especially in lymphoblasts and IgA-containing cells, which reached a peak on day 4 or 5, followed by a ten-fold increase in IgA immunoglobulin and IgA anti-worm antibody which reached a peak 7 or 8 days after challenge. The timing of these events suggested that the cellular, but not the IgA, response could have been involved in a putative mechanism which caused arrested development, although both components could have been implicated in mechanisms which may have caused expulsion of developing larvae.

Animals↗
PubMed1983

Additional restriction endonuclease cleavage sites on the bacteriophage P22 genome.

We present complete restriction endonuclease cleavage site maps of the bacteriophage P22 chromosome for 16 enzymes with six base recognition sequences, thereby positioning 116 new sites on the chromosome. Twenty-four such restriction maps for P22 DNA, containing 162 sites, have now been completed, and three enzymes were found that did not cut P22 DNA. Our results are consistent with the ideas that ClaI does not cleave the methylated recognition sequence ATCGA(me)T or A(me)TCGAT and StuI does not cleave the methylated recognition sequence AGGCC(me)T.

Base Sequence↗
PubMed1983

Coliform mastitis.

The majority of coliform mastitis cases are relatively mild and self-limiting. Teat dipping and dry cow therapy will not prevent coliform problems, neither do they cause them. Bad housing and poor milking time hygiene lead to coliform mastitis. Efforts to control coliform mastitis must be directed at reducing exposure to the bacteria. In acute cases fluid therapy is indicated to counteract endotoxic shock.

Animals↗
PubMed1982

The reaction of xenogeneic and monoclonal antisera with Reed-Sternberg cells.

Xenogeneic antisera have been prepared against human monocytes, B lymphocytes and T lymphocytes. The reactivity of these antisera against a variety of normal and neoplastic cells is described. Reed-Sternberg cells from three cases of Hodgkin's disease failed to react with xenogeneic anti-T and anti-monocyte sera, but reacted with an anti-B serum. A further three cases were examined with monoclonal antibodies. Negative results were obtained with monoclonal anti-T and positive results were given by monoclonal antibodies directed against DR and HLA antigens.

Antibodies, Monoclonal↗
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↗
PubMed1979

Virus infections in children with acute lymphoblastic leukaemia.

The pattern of virus isolation and illness was studied in 64 children with acute lymphoblastic leukaemia (ALL) during periods of apparent infection and when the children were well. The virus isolation rate of 2.2 viruses per child a year is similar to that previously found in normal children. In only 32% of children with symptoms were viruses found and 14.5% had viruses isolated when asymptomatic. The children with ALL appear to be more vulnerable to multiple virus infections and to excrete the virus for longer periods. This may be due to failure of production of both local and systemic antibodies. The failure in the past to recognise the true importance of virus infections in ALL may have been due to inadequate diagnostic techniques.

Adolescent↗