Biomedical subjects

C A Perry

Publications and source records attributed to C A Perry.

46 records · Page 3Linked to original sources

PubMed1987

Hemoglobin autoxidation at physiological concentrations.

Methemoglobin formation was studied at near physiological hemoglobin concentration. The reaction proceeds at a faster rate when the concentration of hemoglobin is high (15-18 mM in heme) than when it is low (2 mM). Constant shaking of hemoglobin preparations during the incubation decreases the differences seen in the rates of autoxidation between concentrated and dilute samples. When red cell hemolysate is used instead of pure hemoglobin, similar results are obtained. A comparison of rates of methemoglobin formation in hemoglobin solutions under low air pressure (1/2 atm) with those under normal air pressure (1 atm) shows no differences between concentrated and dilute samples. There is also no significant difference between the rates of autoxidation of dilute and concentrated solutions when the reactions are carried out under one atmosphere of oxygen (100 percent O2). The study of one patient with hereditary spherocytosis demonstrated higher hemoglobin autoxidation rate in spherocytes, which have higher hemoglobin concentration, than in normal biconcave red cells. These results suggest that: a) the rate of hemoglobin autoxidation at red cell hemoglobin concentration is significantly faster than rates obtained by studying dilute solutions; b) although the accelerated oxidation might be related to multiple factors, one seems to be less accessibility of oxygen when the hemoglobin solution is highly concentrated.

Erythrocytes↗

PubMed1986

Online information retrieval in pharmacy and related fields.

Online information retrieval in pharmacy and related fields is described. Factors involved in determining whether to conduct an online search are discussed, including characteristics of appropriate and less suitable topics, advantages and limitations of online searching versus manual searching, and possible types of searches. The process of preparing for an online search, involving the determination of search vocabulary, relevant citations, important authors, time frame, special categories (such as language, publication type, and reviews), and the number of citations needed, as well as choosing a database, is explained. Sample search strategies on MEDLINE and IPA are illustrated to demonstrate the basic search commands and to compare file retrievals on the sample subject. Pharmacy-related bibliographic databases, general-interest databases, end-user search services, and full-text and numeric databases are profiled. Online database searching can be a cost-efficient and flexible alternative to manual literature searching for pharmacists. Although most online searching is currently conducted by librarian-search specialists, end-user searching is a growing trend, as is the availability of full-text databases.

Abstracting and Indexing↗

PubMed1984

Inhibition of platelet ADP and serotonin release by carbon monoxide and in cigarette smokers.

The release of 14C-serotonin by ADP, epinephrine and arachidonic acid and the release of ADP by kaolin were measured in normal platelets in the presence and absence of carbon monoxide and in smokers' platelets. It is shown that carbon monoxide inhibits significantly the platelet release reaction. This function is also decreased in platelets obtained from heavy cigarette smokers.

Adenosine Diphosphate↗

PubMed1983

The ability of fibrinogens, FI and FII, to support ADP-induced platelet aggregation.

Fibrinogen plays an integral part in ADP-induced platelet aggregation. Controversy exists in regard to the role of the carboxy termini of fibrinogen A alpha chains in this reaction. We have attempted to clarify this problem in view of the availability of a highly purified FII fibrinogen fraction. Kabi fibrinogen or its purified fractions FI, FII and FIII-IV-V were added to washed platelets in the presence of Tyrode-HEPES buffer pH 7.4. Aggregation was initiated by the addition of calcium and ADP. These fibrinogen fractions equally promoted ADP-induced platelet aggregation. The major difference among these fractions is in their A alpha chains. The FI fraction contains intact A alpha chains while FII and FIII-IV-V fractions have one and two partially degraded A alpha chains at the carboxy terminal portion respectively. We conclude that the carboxy terminal portion of the A alpha chain does not play an important role in promoting ADP-induced platelet aggregation.

Adenosine Diphosphate↗

PubMed1983

Eosinophilic granulocytes as a possible source of vitamin B12-binding protein.

Leucocyte B12 and B12-binding capacity were measured by Simultrac radioassay in eosinophilic granulocytes, neutrophilic granulocytes and leucocytes obtained from patients with chronic granulocytic and lymphocytic leukaemia. It is shown that (a) eosinophils are a possible source of B12-binding protein similar to neutrophils and (b) granulocytes in myeloproliferative disorders and normal neutrophils have similar B12 and B12-binding capacity indicating that increased B12 and B12-binding capacity in myeloproliferative disorders arise from an increase in myeloid cell turnover.

Eosinophilia↗

PubMed1982

Alteration of platelet aggregation by cigarette smoke and carbon monoxide.

Platelet aggregation with epinephrine, adenosine diphosphate and arachidonic acid was studied in the presence of cigarette smoke and carbon monoxide. It is shown that cigarette smoke inhibits the arachidonic acid induced platelet aggregation as well as the second phase of epinephrine induced aggregation. The adenosine diphosphate induced platelet aggregation is not significantly affected by cigarette smoke. Carbon monoxide causes similar alterations in platelet aggregation. These results suggest that cigarette smoke inhibits platelet aggregation. This aggregation inhibition is due to the presence of carbon monoxide.

Carbon Monoxide↗

PubMed1945