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Biomedical subjects

M M Kay

Publications and source records attributed to M M Kay.

85 records · Page 5Linked to original sources
PubMed1978

Effect of age on T cell differentiation.

A brief overview of the area of T cell aging is presented by first discussing the age-related changes in T cell activities, and then by focusing attention on the possible mechanisms that may be responsible for the decline. Present evidence indicates that thymic involution precedes and therefore may be responsible for the age-dependent decline in the ability of the immune system to generate functional T cells. At this time, it appears that the primary effect of thymic involution is on a T cell differentiation pathway affecting the more mature T cells first with time, and then the less mature T cells. Thus, the thymus may be the aging clock for the immune system. Further studies should be centered around processes regulating growth and atrophy of the thymus.

Aging↗
PubMed1976

Hodgkin's disease: a war between T-lymphocytes and transformed macrophages?

The interaction between Reed-Sternberg (RS) cells and autogeneic T T cells was investigated. It was found that T cells cytolyse RS cells in the following sequential manner: Stage 1, T cells affix the tips of their microvilli onto target cells, Stage 2, T cells subject cell membranes to tearing, and shearing forces which produce gaps and holes; Stage 3, target cells lyse and T cells "crawl" away. The relationship between the events occurring at the cellular level and those observed clinically are discussed. Hodgkin's disease holds a fascination for clinicians and "bench" scientists alike, perhaps because of the enigma and challenge it represents. It is not surprising, therefore, that many questions go unanswered. For example, we are still addressing ourselves to the following questions: What is the origin of the Reed-Sternberg (RS) cell? If a macrophage, then why do T cells attach to it and what is the nature of the T cell-RS interaction? Why is cellular immunity so often impaired even in patients in the early stages of the disease? Why do patients with Hodgkin's disease sometimes develop autoimmune hemolytic anemia when they are, in fact, immunologically hyporesponsive? In this paper, I shall present evidence which answers a few of these questions and provides hypothetical answers to the others.

Hodgkin Disease↗
PubMed1976

Autoimmune disease: the consequence of deficient T-cell function?

The age-related decrease in T-lymphocyte function is discussed in relation to the onset of autoimmune disease. It is postulated that the decrease in T-cell "immune surveillance" permits: a) the ingress of viruses whose enzymes modify host glycoproteins and render them immunogenic, and b) the replication of viruses incorporated into the genome of cells during infections in early life. The existence of immunodeficiencies too subtle to be detected by our present laboratory methods is postulated and discussed in relation to diseases observed in geriatric patients. It would seem that the prevention of some geriatric diseases should begin in the pediatrician's office.

Aging↗
PubMed1975

Mechanism of removal of senescent cells by human macrophages in situ.

Mechanisms by which macrophages discriminate between "mature-self" and "senescent-self" were investigated using the human red blood cell (RBC) system as a model. Conditions simulating those encountered in situ were adhered to as closely as possible by using short term culture techniques and incubating with autologous macrophages and immunoglobulins (Ig). It was found that RBC aged in vitro were phagocytized when they were incubated in pooled, normal human IgG, allogeneic Ig, autologous IgG or Ig, washed with medium, and then incubated with autologous macrophages. RBC treated in the same way but incubated in IgM or Iga, Ig-depleter serum, or Medium 199 alone were not phagocytized. This indicates that Ig is required for phagocytosis and suggests that the Ig which attaches to RBC is IgG. When freshly drawn RBC were separated into young (Y) and old (O) RBC according to density and incubated with autologous macrophages, less than 5% of the Y-RBC were phagocytized, whereas greater than 30% of the O-RBC were phagocytized, independent of whether the final incubations were performed in medium without serum (Y-RBC, 5 +/- 2% phagocytized; O-RBC, 33 +/- 1.5%), or autologous Ig-depleted serum (Y-RBC, 2 +/- 2.5%; O-RBC, 51 +/- 17%), or whole serum (Y-RBC, 0%; O-RBC, 43 +/- 5%). This indicates that (1) the Ig is attached in situ to the old RBC, and (2) that phagocytic recognition is not inhibited by other serum components. Scanning electron microscopy, employing labeled anti-IgG, IgM, and IgA reagents, revealed that Y-RBC had essentially no Ig on their surface, whereas old RBC had IgG on their surface. These findings indicate that IgG attaches in situ to senescent human RBC, making them vulnerable to phagocytosis by macrophages.

Binding Sites↗
PubMedDate not supplied

A comparison of practice domains of clinical nurse specialists and nurse practitioners.

This qualitative study was carried out to add empirical data to the discussion of the essentials of advanced practice graduate nursing education. Study participants were 15 nurse practitioners (NPs) whose original preparation was as clinical nurse specialists (CNSs). These nurses subsequently completed post-master's preparation as NPs at a midwest US school of nursing. The nurses were interviewed regarding similarities and differences between the NP and CNS roles based on their own experiences. They stated that their 1-year post-master's NP educational program broadened their knowledge base and increased their skills of direct data collection in history taking and physical examination. They described increased NP role autonomy and clinical decision making. Comparison of study results with the six practice domains of the National Association of Nurse Practitioner Faculties (NONPF) Curriculum Guidelines appeared to verify the NONPF domains as being operant in advanced nursing practice. Each role had distinct expression of the NONPF practice domains, particularly in two areas: management of client health-illness states and the professional role. Results suggest that advanced practice graduate nursing curricular content needs to be explicit regarding CNS and NP role domains to retain the respective strengths of each. A "hybrid" CNS/NP curriculum faces the danger of lacking both the depth and specificity of knowledge that has resulted in the roles' past successes.

Attitude of Health Personnel↗