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Biomedical subjects

J T Barrett

Publications and source records attributed to J T Barrett.

49 records · Page 3Linked to original sources
PubMed1970

Characteristics of the Hemagglutinin Produced During Plasmodium lophurae Malaria in Chickens.

During the course of Plasmodium lophurae infections in normal chickens, there was a sharp increase in the titer of a hemagglutinin which reacted better with trypsinized than with normal erythrocytes. This hemagglutinin was a typical "cold hemagglutinin" in that it was much more active at 4 C than at 37 C, was found in the macroglobulin fraction of the serum, was eluted from erythrocytes at 37 C, and was easily destroyed by 2-mercaptoethanol reduction. The injection of allogeneic erythrocytes into chickens prior to their exposure to P. lophurae resulted in a coexistent increase in cold hemagglutinin titers and enhanced resistance to parasitemia. Since this antibody was more active against altered erythrocytes than against normal erythrocytes, it may moderate resistance to malarial infections by specifically stimulating phagocytosis of parasitized erythrocytes.

Journal Article↗
PubMed1968

Hemagglutination and hemolysis by : lichen extracts.

Twenty-two species of lichens from 10 different genera possessed a hemagglutinin for one or more of human, sheep, horse, cow, rabbit, guinea pig, and chicken erythrocytes. Hemolysins were also detected occasionally, but these were only active at low dilutions. In those species tested, the hemolytic principle was dialyzable; the hemagglutinating agent was not. Preliminary studies have indicated that the lichen hemagglutinins are nonspecific.

Journal Article↗
PubMedDate not supplied

Spectrophotometric evaluation of carboxyhemoglobin in blood of mice after exposure to marijuana or tobacco smoke in a modified Walton horizontal smoke exposure machine.

Carboxyhemoglobin (COHb) values were determined in mice exposed to varying amounts of marijuana and tobacco cigarette smoke utilizing a spectrophotometric technique. Mice were exposed to smoke inhalation in a modified Walton horizontal smoke exposure machine, whereby rodents can be exposed to multiples of 1-min smoke exposure cycles. Smoke exposure was intermittent; during the first 30 sec of each 1-min cycle, the subjects were exposed to smoke diluted either 1:10 or 1:5 with air. During the second half of the cycle the animals were given fresh air. There was a positive linear relationship between COHb values obtained and the number of puffs of marijuana smoke administered via either 2, 4, 6, or 8 "puffs" of marijuana smoke. COHb levels in plasma did not increase in animals given multiple 8-puff episodes of smoke daily as long as a 60-min period was interposed between smoking episodes. COHb values in mice exposed to tobacco smoke were significantly higher than those in mice receiving equal numbers of exposures to marijuana smoke. Mean COHb values of mice receiving 8 consecutive puffs of marijuana smoke were 18.6 and 22.0% saturation, but CO was rapidly cleared from the blood. This rapid clearance suggests that the binding affinity of CO for mouse hemoglobin may be be weaker than that of human hemoglobin. Mice similarly exposed to 6 or 8 puffs of tobacco smoke had mean COHb values of 24.6 and 28.5% saturation, respectively. No acute lethal effects were observed in mice receiving multiple daily episodes of 8 puffs per episode of marijuana smoke, whereas mice exposed to a single 8-puff episode of tobacco smoke suffered about 50% acute lethal effects.

Animals↗
PubMedDate not supplied

Presentation of nursing diagnosis content in fundamentals of nursing textbooks.

The technique and rationale for the use of nursing diagnosis generally are introduced early in the undergraduate curriculum. The three purposes of this descriptive study were to describe the general characteristics and presentation of content on nursing diagnosis in fundamentals of nursing textbooks; describe how the content from the theoretical chapter(s) in nursing diagnosis is carried through in the clinical chapters; and describe how content on diagnostic errors is presented. Although most of the textbooks presented content on nursing diagnosis in a similar fashion, the clinical chapters of the books did not follow the same pattern. Content on diagnostic errors was inconsistent. Educators may find this an effective methodology for reviewing textbooks.

Curriculum↗
PubMedDate not supplied

Chemotaxis by lipids isolated from Bacteroides fragilis.

Living, heat or formalin killed Bacteroides fragilis and a crude preparation of their cell walls were examined by the Boyden technique for chemotactic activity upon guinea pig peritoneal exudate cells. Their relative chemotactic activity ranged from 3.0 to 5.2 compared to an average value of 6.4 for the positive control, an endotoxic culture filtrate of Escherichia coli. A culture filtrate of B. fragilis and an index of 3.7. Miocrogram quantities of cytoplasmic preparations obtained by ammonium sulphate precipitation had chemotactic indices ranging from 2.8 to 6.4, the highest value being displayed by the precipitate formed between 50 and 75% saturation with ammonium sulphate. This fraction retained leucotactic activity after exposure to strong acid and heat. The leucotactic potency of these fractions did not correlate directly with their protein content. Further precipitation of the most active fraction with 80% ethanol revealed that there was little chemotactic activity attributable to polysaccharides. Gas liquid chromatography of a chloroform-methanol extract of the cells which had a chemotactic index of 6.1 revealed the presence of more than thirty fatty acids ranging in carbon length from C8 to C25. These results suggest a role of lipids as initiators of the leucotactic response associated with infections caused by B. fragilis.

Animals↗