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Biomedical subjects

C West

Publications and source records attributed to C West.

189 records · Page 11Linked to original sources
PubMedDate not supplied

Synergy between TLR2 and TLR4: a safety mechanism.

BACKGROUND: The Toll (Tlr) receptors facilitate innate immunity by detecting products that are unique to invading microorganisms. Stimulation of these receptors can produce severe reactions and death. We propose that synergy between receptors for different microbial products would provide a safety mechanism, preventing inappropriate, potentially fatal reactions by reacting to low concentrations of ligands when more than a single ligand is present. RESULTS: Striking synergy is noted between the ligand for Tlr4, lipopolysaccharide (LPS), and a ligand for Tlr2, muramyl dipeptide (MDP), in the release of tumor necrosis factor from RAW cells. CONCLUSIONS: Synergy between a ligand for Tlr2 and Tlr4 can be demonstrated in a simple in vitro system. The greater sensitivity of MDP-stimulated cells to LPS may explain the data that were once interpreted incorrectly as indicating that Tlr2 is the endotoxin receptor.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMedDate not supplied

A study of genes that may modulate the expression of hereditary hemochromatosis: transferrin receptor-1, ferroportin, ceruloplasmin, ferritin light and heavy chains, iron regulatory proteins (IRP)-1 and -2, and hepcidin.

We have examined transferrin receptor-1, ferroportin, ceruloplasmin, ferritin light and heavy chains, iron regulatory proteins (IRP)-1 and -2, and hepcidin for mutations that might modulate the iron burden of individuals harboring the common mutant hemochromatosis HFE genotype C282Y/C282Y or cause hemochromatosis independent of mutations in the HFE gene. In a group of white, Asian, and African-American normal and iron-overloaded individuals, the coding and flanking regions of these genes were completely sequenced. Numerous coding region and promoter polymorphisms were detected. These were further examined for association with differences in iron accumulation as measured by plasma transferrin saturation and ferritin levels, but no such association could be documented.

Antimicrobial Cationic Peptides↗
PubMedDate not supplied

Group interventions for anger in people with intellectual disabilities.

This paper describes an evaluation of a group intervention for reducing inappropriately expressed anger (as aggression) in people with intellectual disabilities. Group intervention was compared to a treatment as usual group consisting of people referred to the group but who had to wait to participate. The intervention used was based on the work of Novaco (1976; 1978) and Benson (1994). However, further modifications to the group that emphasized the contextual perspective of anger, such as the participants being accompanied by a support worker and more collaborative recording procedures, were devised. A reduction in expressed anger and measured levels of depression occurred after group treatment. Reductions in expressed anger were maintained at 6 and 12 months follow up. However, scores on the depression scale tended to increase on follow up. While caution must be expressed when considering these results, this type of intervention shows promise for reducing inappropriately expressed anger in people with intellectual disabilities Suggestions are made for future research and clinical practice.

Adult↗
PubMedDate not supplied

Measurement of the viability of stored red cells by the single-isotope technique using 51Cr. Analysis of validity.

A single-isotope 51Cr method often is used to evaluate the viability of stored red cells. In this technique, the red cell mass is measured by back-extrapolation to time zero (t0) of the radioactivity of the blood between 5 and 20 minutes after infusion of the sample. If there is early destruction of stored cells, this method provides an overestimate of the red cell mass and, hence, of the viability of the stored cells. Freshly drawn red cells from normal donors were labeled with 99mTc, and cells from the same donor which had been stored in citrate-phosphate-dextrose-adenine-one (CPDA-1) for periods ranging from 7 to 49 days were labeled with 51Cr. A comparison of the "true red cell mass" as determined with 99mTc with the back-extrapolated red cell mass from stored 51Cr-labeled cells has made it possible to define the magnitude of error introduced by early loss of red cells. The overestimation of red cell mass and viability was diminished if only the 51Cr radioactivity between 5 and 15 minutes after infusion was used in back-extrapolating to t0. The degree of overestimation of red cell mass was greatest when the red cell viability had declined to very low levels. However, in the entire range of 10 to 80 percent viability, the overestimate of viability was usually less than 4 percent. The overestimate of viability proved to be quite similar for all samples and may be taken into account when using the single-isotope technique for measurement of red cell viability.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Glycolytic enzymes of stored granulocytes.

A marked reduction of granulocyte chemotactic function accompanies the storage of granulocyte concentrates. Since chemotaxis is energy dependent, we studied energy metabolism in stored neutrophils. We and others have reported that stored neutrophils have a defect in their energy metabolism. We found that defective adenosine triphosphate maintenance in stored neutrophils was occult in resting cells, but was unmasked by an energy-intensive stimulus, phagocytosis. In studies reported here, we sought to determine if defective adenosine triphosphate maintenance during granulocyte storage was related to altered glycolytic enzyme activity. We studied the activity of glycolytic enzymes in fresh and stored, resting and stimulated (opsonized zymosan) neutrophils. The following enzyme activities showed no major changes during storage, in resting or stimulated neutrophils: hexokinase, phosphofructokinase, aldolase, glucose phosphate isomerase, triose phosphate isomerase, glyceraldehyde phosphate dehydrogenase, phosphoglycerate kinase, phosphoglyceromutase, enolase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, glutathione reductase, and glutathione peroxidase. In contrast, pyruvate kinase activity consistently increased during storage. In 6 units, pyruvate kinase activity increased by 75 percent after 24 hours of storage at room temperature and by 198 percent after 48 hours. The storage-associated increase in pyruvate kinase activity was not inhibited by cycloheximide. Stimulation of neutrophils by phagocytosis of opsonized zymosan also produced striking increases in the pyruvate kinase activity of both fresh and stored cells. Additional studies indicated that the increases in pyruvate kinase activity observed during storage and after phagocytosis were associated with an increase in the availability of pyruvate kinase activity in the supernatant fraction of neutrophil sonicates. Total pyruvate kinase activity in sonicates of neutrophils was unchanged by storage or particle ingestion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMedDate not supplied

The effect of additives on red cell 2,3 diphosphoglycerate levels in CPDA preservatives.

Forty-two chemical substances, chosen because they might influence red cell metabolism, were screened for effect on red cell adenosine triphosphate and 2,3 diphosphoglycerate (2,3 DPG) levels during storage in CPD or CPDA-1 at 4 degrees C. Of these substances, six appeared on initial screening to increase 2,3 DPG levels during storage; on repeated examination, four compounds, i.e., oxalate, glyoxalate, ethyl oxaloacetate, and L-phenylalanyl-L-alanine, consistently increased 2,3 DPG levels during storage. It was shown that glyoxalate was converted rapidly to oxalate in blood, presumably through the lactate dehydrogenase reaction. Ethyl oxaloacetate is known to hydrolyze, giving rise to oxalate. Thus, the effect of both glyoxalate and ethyl oxaloacetate can be explained by the formation of oxalate, a compound already known to increase 2,3 DPG levels. The effect of L-phenylalanyl-L-alanine remains to be explained, but it may be hydrolyzed to L-alanine and L-phenylalanine, both of which are thought to have the capacity to increase red cell 2,3 DPG levels by inhibiting pyruvate kinase activity.

2,3-Diphosphoglycerate↗