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Biomedical subjects

R Walker

Publications and source records attributed to R Walker.

At least 397 records · Page 22Linked to original sources
PubMed1979

Prostaglandins and the contractile action of bradykinin on the longitudinal muscle of rat isolated ileum.

1. The effect of the prostaglandin synthesis inhibitors aspirin and indomethacin (Ind) was investigated upon contractions of the perfused isolated terminal ileum of the rat to bradykinin (Bk) or potassium chloride (KCl). The release of a prostaglandin-like substance (PGLS) from the ileum was simultaneously assayed on the rat fundus strip (RFS). 2. Aspirin (610 micro M) or Ind (28 micro M) reduced contractions of the ileum to Bk perfused over the mucosal surface but not to Bk perfused over the serosal surface. 3. After perfusion of either ileal surface the effluent potentiated the contractions of the RFS to Bk. No potentiation was observed in the presence of either Ind or aspirin. 4. Contractions of the RFS to Bk were potentiated by prostaglandin E2 (PGE2) (0.7 X 10(-12) M and 1.4 X 10(-12) M) but not by either a higher (2.8 x 10(-12) M) or a lower (0.35 X 10(-12) M) concentration of PGE2. No potentiation was observed with prostaglandin F2 alpha (PGF2 alpha) at the concentrations studied. 5. Only the contractile action of Bk acting on the mucosal surface of the rat isolated perfused ileum seems to involve prostaglandin synthesis.

Animals↗
PubMed1979

The Comprehensive Blood Bank Survey Program of the College of American Pathologists--1977.

The 1977 CAP Comprehensive Blood Bank Survey was sent to 2487 laboratories in the United States and five foreign countries. The results show that ABO and Rh testing has a continued concurrence of greater than 94.8% between participating and referee laboratories, while antibody detection was 95.9% effective on the type problem normally encountered in a transfusion service. Cross match showed a concurrence rate of 97.3% or better. Although these testings are artificial and cannot be directly extrapolated into effectiveness of patient care, they can be compared with each other and show a standard of excellency in the laboratory which is a good or better than that found in previous studies. A series of ungraded specimens and questionnaires shows that most laboratories used a 51 degree C heat elution method for antibody elution, but slightly better results were obtained with the Rubin technic. A second study showed that the grading of a positive direct antiglobulin test was fairly reproducible throughout the country.

Antibodies↗
PubMed1978

The Comprehensive Blood Bank Survey Program of the College of American Pathologists, 1976.

The Comprehensive Blood Bank Survey Program for 1976 still shows that the participants are performing well on ABO and Rh typing (accuracy greater than 96.6%), antibody detection (greater than 97.0%), and crossmatching (greater than 97.3%). The only problem with less accuracy than that stated involved a specimen with an extremely weak antibody. Some errors are still due to failure to fill out results. In the 1976 survey, four ungraded problems were included as attempts to study the "state of the art." The problems consisted of an antibody whose titer was to be determined, a mixture of Rh+ and Rh-- cells to be detected, and two multiple-antibody problems. The results obtained in these studies are discussed. Finally, the participants were asked questions about the amount of Rh immune globulin used and the indications for its use, the incidence and types of transfusion reactions seen, and the notations used by laboratories to record results. The answers to these questions are also documented.

ABO Blood-Group System↗
PubMed1978

Nutritional and toxicological properties of some raw and modified starches.

Several food additives, including some raw and chemically modified starches, sorbitol and maltitol, cause caecal enlargement when fed to rodents. The onset of caecal enlargement is rapid and it is reversible when the additive is withdrawn. This poses problems in the safety evaluation of such additives, both in relation to the significance of the caecal enlargement and to the associated effects on food efficiency and nitrogen balance. The mechanisms of causation of caecal enlargement have been studied and will be discussed with particular reference to resistance of starches to enzymic hydrolysis, changes in intestinal microflora, osmotic load in the caecum, cell hyperplasia and rate of turnover of mucosal cells. Where deaths occur, these appear to be due to secondary effects such as impaired resporatory function.

Animals↗
PubMed1977

Toxocara canis.

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Animals↗