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Biomedical subjects

J Alexander

Publications and source records attributed to J Alexander.

656 records · Page 37Linked to original sources
PubMedDate not supplied

Growth stimulation of intestinal tumours in Apc(Min/+) mice by dietary L-methionine supplementation.

We studied the effects of extra dietary methionine on the formation and growth of intestinal adenomas in the Min (Apc+/-) mouse, which is a murine model of the human familial adenomatous syndrome. The AIN-76A diet was supplemented with 0.7% L-methionine from week 4 after birth and the animals were killed at week 8. The number of tumours in Min mice was apparently not affected by the addition of extra methionine. However, the dietary methionine supplementation increased the surface area of small intestinal tumours by 41% (p=0.009). In the colon, extra methionine did not affect tumour size. In conclusion, extra dietary methionine promotes the growth of adenomas in the small intestine of Min mice.

Adenoma↗
PubMedDate not supplied

Acral erythema during bone marrow transplantation: a case study.

Six of 13 patients receiving high-dose cytosine arabinoside as preparation for bone marrow transplant experienced painful redness and blistering of the hands and feet. Literature reports described this syndrome in patients receiving high-dose chemotherapy but at lower rates of occurrence than in this series of patients. Nursing problems encountered in patients experiencing acral erythema included: pain, compromised self-care, decreased activity, and infection potential. Nursing measures for dealing with these problems are described.

Bone Marrow Transplantation↗
PubMedDate not supplied

Role of splenectomy in prevention of hemorrhagic enteritis and death from hemorrhagic enteritis virus in turkeys.

Hemorrhagic diarrhea, gross hemorrhagic enteritis, and death caused by intravenous virus injection of hemorrhagic enteritis virus (HEV) were prevented in otherwise susceptible turkey poults by surgical splenectomy. The splenectomized poults produced anti-HEV antibodies, which indicated that splenectomy did not completely prevent replication of the virus. These results indicate that the spleen is necessary for the development of the intestinal lesions of this disease. The role of a toxic factor in this disease is discussed.

Animals↗
PubMedDate not supplied

Demonstration of natural Leishmania infection in asymptomatic dogs in the absence of specific humoral immunity.

Asymptomatic dogs from a Kala-Azar endemic region were screened for infection status by parasitological, immunological and molecular techniques. Bone marrow was examined for the presence of parasites by NNN culture and by using the Lmet 2 DNA probe. All the samples were negative in culture but 24 of 41 were positive as determined by the probe. Cellular and humoral immunity were detected by T cell proliferation assays and IFAT respectively. Specific cellular and humoral immunity were found in 20 and 26 dogs respectively out of a total of 41 dogs examined. The vast majority of dogs with Leishmania-specific antibodies were found to be parasitologically positive using the DNA probe while almost half those that had demonstrable cellular immunity were apparently parasite free. The observation that dogs can develop cellular immunity following natural infection clearly indicates that there is a spectrum of canine leishmaniasis similar to that observed in the human disease. The prevalence of dog leishmanial infection must also be higher than was presumed.

Animals↗
PubMedDate not supplied

Antigen analogues as antagonists of the T cell receptor.

Complexes of antigen analogues and major histocompatibility complexes have been demonstrated to function as effective antagonists of the T cell receptor (TCR). It was observed that modification of any of the major T cell contact residues can create powerful TCR antagonists. Increasing similarity of antagonist to antigen structure resulted in increased capacity to act as a TCR antagonist up to a point beyond which the analogues themselves showed antigenicity. These data strongly suggested that peptide: TCR interaction with a certain low affinity may still be sufficient for engagement of the receptor but not for signalling, thus resulting in antagonism. It was found that the presentation of antagonistic peptides alone did not induce the formation of stable conjugates between antigen presenting cells and T cells, but rather that presentation of antigen was required to induce the initial interaction of APC with T cells in cell:cell conjugates. This antigen-dependent conjugate formation was not affected by the antagonist, while very early intracellular biochemical events such as PI turnover and CA2+ flux were inhibited.

Antigen-Presenting Cells↗