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Biomedical subjects

M A Lamb

Publications and source records attributed to M A Lamb.

30 records · Page 2Linked to original sources
PubMed1982

Platelet adhesion to damaged coronary arteries: Comparison in normal and von Willebrand disease swine.

The early response to coronary artery injury was investigated in normal swine and in swine with von Willebrand disease (vWD). Thirty minutes after coronary endothelial denudation, a monolayer of platelets was adherent to areas of simple injury in both bleeder and normal swine. The number of adherent platelets was not significantly different in the two phenotypes. Injury involving the media of the vessel produced platelet-fibrin thrombi. Platelet activation, as judged by pseudopod formation and platelet spreading over areas of simple injury, was significantly less in bleeder animals than in normal animals. These studies suggest that chemotaxis and initial contact adhesion of platelets to injured arterial wall is independent of the von Willebrand factor. On the other hand, the spreading and activation of platelets on the subendothelium appear to be dependent on the presence of plasma von Willebrand factor. Through this mechanism von Willebrand factor may contribute to arterial thrombosis and atherogenesis.

Animals↗
PubMed1981

The multimeric distribution of factor VIII-related antigen studied by an improved crossed-immunoelectrophoresis technique.

An improved XIEP technique has been described that is capable of resolving under nondenaturing conditions at least five populations of FVIIIR:Ag directly from microliter amounts of normal human plasma. Resolution has been achieved by increasing the concentration of agarose in the electrophoretic medium to 2% or 3% and extending the period of electrophoresis to take advantage of molecular sieving effects. Normal human plasma demonstrates an electrophoretic pattern indicating that the majority of FVIIIR:Ag is assembled as higher-molecular-weight multimers. The distribution of FVIIIR:Ag appears to be independent of antigen concentration and sample storage temperature. Plasmas from two individuals with variant VWD demonstrate a lack of the higher-molecular-weight multimers coupled with an absolute increase in the lower-molecular-weight antigenic populations, suggesting a defect in antigen assembly. Commercial FVIII preparations, reported to be ineffective in correcting the bleeding abnormality in VWD, have also been found to lack the higher-molecular-weight multimers. On the other hand, cryoprecipitate, preferred in the treatment for VWD, had essentially the same antigen distribution as normal plasma. The similarities in the distribution of FVIIIR:Ag in variant plasmas and commercial FVIII concentrates provide further evidence that it is primarily the higher-molecular-weight multimers that function in maintaining hemostasis.

Adolescent↗
PubMed1980

Structure-function of the factor VIII complex studied with an immobilized heteroantisera to VIII:C.

An antibody was raised in rabbits to the small active fragment of human factor VIII, obtained by Ca2+ dissociation of a human factor VIII preparation made from a multidonor plasma pool. After absorption, the antibody neutralized the factor VIII coagulant activity of normal human plasma, but did not precipitate with any plasma or plasma fractions or neutralize von Willebrand factor (vwf) activity as measured by ristocetin aggregation of fixed washed platelets. Immune beads were prepared by CNBr binding of the partially purified rabbit antibody to 1% agarose beads. Non-immune beads were prepared with IgG fractions obtained from the rabbits before immunization and used throughout as a control. The amount of factor VIII coagulant activity (VII:C) removed from plasma by immune beads was time-dependent and proportional to the amount of beads used, but all of the VIII:C could not be readily removed. Removal of VIII:C by immune beads parallelled removal of factor VIII:antigen, but less VWF activity was removed. Immune beads could be blocked or saturated by treatment with large amounts of normal plasma, but not by von Willebrand disease plasma and only by some haemophilic plasma.

Absorption↗
PubMedDate not supplied

Concept analysis of relating: a human response pattern.

TOPIC: An investigation of relating, one of the nine human response patterns, used as the conceptual basis for the classification of nursing diagnoses. PURPOSE: A formal linguistic analysis of each of the nine human response patterns is warranted in order to allow a continuation of the exploration, definition, and development of research-based practice based on the NANDA framework. SOURCE: "Human Response Patterns" developed by NANDA, historical foundations of the concept of relating, the use of this construct by nursing and other disciplines. CONCLUSIONS: Concept analysis of relating resulted in conceptual and operational definitions. The efficacy of further developing nursing's taxonomic tree on the nine human response patterns has been advanced.

Adolescent↗
PubMedDate not supplied

Smooth muscle cell proliferation in response to endothelial injury in coronary arteries of normal and von Willebrand's disease swine.

The proliferative response of medial smooth muscle cells to balloon-induced endothelial denudation was measured in coronary arteries of normal and von Willebrand's disease swine, a strain of swine with a genetic defect affecting platelet-vessel wall interactions. Animals were sacrificed 48 hours following endothelial injury. Incorporation of a 1-hour pulse label of 3H-thymidine was determined by measuring DNA specific activity. Autoradiography of coronary artery step segments was also performed. The ratio of DNA specific activity in ballooned vessels to that in nonballooned vessels ranged from 1.2 to 26.2. No statistically significant difference in 3H-thymidine incorporation between the two phenotypes was documented (p greater than 0.25). Similarly, DNA incorporation of 3H-thymidine as determined by autoradiography was accelerated to the same degree in ballooned vessels in both phenotypes. The results suggest that von Willebrand factor-mediated platelet activation is not essential for the release of platelet-derived growth factor or that in vivo factors other than platelet-derived growth factor play a significant role in the response of medial smooth muscle cells to acute intimal injury causing endothelial denudation.

Animals↗
PubMedDate not supplied

Development of coronary atherosclerosis in swine with severe hypercholesterolemia. Lack of influence of von Willebrand factor or acute intimal injury.

The development of coronary atherosclerosis in response to acute intimal injury and severe hypercholesterolemia was studied in 18 swine, nine normal and nine with von Willebrand's disease, an inherited disorder affecting platelet-vessel wall interactions. The left anterior descending coronary artery was denuded of endothelium by balloon catheterization, while the circumflex and right coronary arteries served as nonballooned controls. All swine were maintained on a 2% cholesterol diet for 4 months. The extent of atherosclerotic involvement was evaluated from four indices: percent intimal area, percent luminal narrowing, ratio of intimal to medial area, and luminal form. No differences in coronary atherosclerosis were observed between phenotypes in either ballooned or nonballooned vessels, nor were there any differences between ballooned and nonballooned vessels within either phenotype (p greater than 0.05). The major variable affecting coronary atherosclerosis was serum cholesterol. There was a significant positive relationship between serum cholesterol concentration and the extent of intimal lesions (r = 0.62, p = 0.006) that was independent of plasma von Willebrand factor concentration. These findings suggest that severe hypercholesterolemia promotes the development of porcine coronary atherosclerosis through a mechanism(s) that is independent of acute intimal injury or von Willebrand factor-mediated platelet response to injury.

Animals↗
PubMedDate not supplied

The sexual adaptation of women treated for endometrial cancer.

This study explores the process of sexual adaptation in women treated for endometrial cancer. Methodology was primarily qualitative with in-depth interviews. Data were collected by means of semistructured tape-recorded interviews; detailed field notes; and quantitative measures of self-concept, self-esteem, body image, and satisfaction with sexual functioning. The quantitative instruments used to measure these constructs were the Tennessee Self-Concept Scale and three visual analog scales. A vivid picture of women's experience of sexual adaptation after treatment for endometrial cancer emerged. This study's findings indicate that the experience of sexual adaptation in women who undergo treatment for endometrial cancer is a process that evolves. This process begins with the onset of symptoms and continues beyond the completion of therapy. Factors that enhanced the adaptational process were identified by the participants.

Adaptation, Psychological↗