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Biomedical subjects

M E Hamilton

Publications and source records attributed to M E Hamilton.

26 records · Page 2Linked to original sources
PubMed1981

Age influences the clinical and serologic expression of systemic lupus erythematosus.

The clinical and serologic characteristics of 17 patients with onset of systemic lupus erythematosus (SLE) after age 50 were compared with those of 49 younger patients. All patients were followed prospectively for a mean duration of 47 months. A clinical and serological data base was established for each patient, and information collected at each visit to a lupus clinic was analyzed by computer. The clinical featured distinguishing old-age SLE were a low incidence of significant renal disease and prominent pleuropericarditis and arthritis throughout the period of followup. Serologic abnormalities were milder in older patients. Thus, hypocomplementemia, anti-DNA antibodies, and C1q precipitins occurred less frequently, and rheumatoid factor was more often present than in younger patients with SLE. Regression analysis suggested linear change in disease expression with age rather than distinct age-related subgroups.

Adult↗
PubMed1980

Simultaneous gout and pyarthrosis.

Although infrequently reported, the simultaneous occurrence of gout and infection in the same joint has been noted recently in three patients at the University of Virginia Hospital. Our report suggests that gout and pyarthrosis may coexist more often than is generally recognized and emphasizes the necessity of carefully searching for both conditions in an inflamed joint. The importance of adequately treating gout occurring with infection is also illustrated. Although speculative, factors such as synovial fluid pH, endotoxin, and enzymatic digestion of articular cartilage may predispose an infected joint to acute gout.

Aged↗
PubMed1979

Tgamma cells in systemic lupus erythematosus. Variation with disease activity.

Circulating T cells bearing receptors for the Fc portion of IgG (T gamma) were identified by sensitive immunofluorescent techniques with rabbit IgG b4 allotype/anti-b4 complexes. A twofold decrease in both proportion and absolute number of T gamma cells was found in patients with active systemic lupus erythematosus (SLE) relative to values obtained during disease remission. The reduction in T gamma cells was most evident in patients with severe hypocomplementemia. A deficit of T gamma cells in active patients was not demonstrated. The percentage of total T cells rosetting with sheep erythrocytes was reduced in peripheral blood of most patients regardless of disease activity status, but particularly during SLE exacerbation. Cells lacking intrinsic surface immunoglobulin, IgG Fc receptors, and receptors for sheep erythrocytes were increased. These cells, operationally termed null, exhibited an inverse linear relationship with T cells that was not apparent in regression analyses performed against other lymphocyte subpopulations. Such differences were not found for B cells and IgG receptor-bearing non-B/non-T cells which were present in normal proportions in virtually all patients. The origin and functional significance of these unusual lymphocyte subpopulation abnormalities are discussed.

B-Lymphocytes↗
PubMed1977

Fc receptor heterogeneity: immunofluorescent studies of B, T, and "third population" lymphocytes in human blood with rabbit IgG b4/anti-b4 complexes.

IgG Fc receptors on human peripheral blood lymphocytes (PBL) were characterized by immunofluorescence studies with defined rabbit IgG b4 allotype/anti-allotype complexes. Three discrete types of Fc receptor-bearing cells, totaling approximately 33% of PBL, were identified. Fc receptors of the three types differed in their sensitivity to trypsin and in either absolute or localized density (topography) as determined by variable requirements for anti-IgC cross-linking in order to visualize bound complexes microscopically. The question of additional heterogeneity related to differences in individual Fc receptor affinity for complexed IgG was not approached in this study. Ten to 15% of PBL had pronase-sensitive, trypsin-resistant Fc receptors readily detected by direct immunofluorescence by using large fluorescein-conjugated complexes prepared near equivalence. Double label and lymphocyte fractionation experiments established this population to be largely distinct from suface IgM+ B cells and T cells, and identical to EA Ripley rosette-forming cells. Approximately 50% of surface IgM+ B cells and approximately 10% of T cells had lower density Fc receptors identified by indirect immunofluorescence with small complexes prepared in antigen excess or by cross-linking fluorescein-conjugated complexes with anti-rabbit IgG anti-serum. An additional approximately 15% peripheral T and B cells had very low density Fc receptors detectable by complexing the IgG on the cell surface by sequential incubations of cells with b4 IgG and anti-b4. Fc receptors on B and T cells were sensitive to both pronase and trypsin digestion. The heterogeneity of IgG Fc receptors on different lymphocyte subpopulations as defined by these these experiments may be of relevance for further analysis of normal and abnormal immune function.

Animals↗
PubMed1966

Operation WASP.

Explore the source record for details and available documents.

Adolescent↗
PubMedDate not supplied

Neurochemical, endocrine and immunological responses to stress in young and old Fischer 344 male rats.

Two experiments were performed. In the first, a 20 min conditioned emotional response (CER) paradigm was used to compare the neurochemical, endocrine and immunological responses to stress of 7- and 22-month-old Fischer 344 (F344) male rats. In the second, corticosterone levels 20 min following ether stress, and regional brain type I and II corticosterone receptor densities were examined using 7- and 17.5-month-old F344 male rats. Dopamine (DA) metabolism in old nonstressed rats was significantly reduced in the medial frontal cortex, neostriatum, nucleus accumbens and hypothalamus, but not in the amygdala. The CER procedure, nevertheless, increased medial frontal cortical, nucleus accumbens and amygdaloid DA turnover in both the young and old rats. The young and old nonstressed rats did not evidence differences in norepinephrine (NE) and serotonin (5-HT) concentrations. However, stress resulted in a decrease in medial frontal cortical 5-hydroxyindoleacetic acid (5-HIAA) and hypothalamic 5-HT levels in old but not in young animals. These observations suggest age-related differences in the response of central NE and 5-HT systems to stress. Ether and the CER procedure led to exaggerated corticosterone responses in the old rats (17.5 and 22 month, respectively). Hippocampal type I but not type II corticosterone receptors were decreased by 47% in the 17.5-month-old rats. Thus, age-related changes in hippocampal corticosterone receptor types do not occur in unison, and the exacerbated corticosterone response to stress precedes the reported down-regulation of hippocampal type II corticosterone receptors in aged rats. Age-related changes were not observed in the concentrations of corticosterone receptors in other brain regions, or in the prolactin response to stress. The old rats, however, evidenced a reduction in the availability of the renin substrate, angiotensinogen, and in stress-induced renin secretion. Immune function was impaired in the old nonstressed rats, and further compromised by exposure to the CER procedure. In comparison to the young control rats, the old nonstressed rats showed an increased percentage of splenic large granular lymphocytes, reduced splenic natural killer cytotoxicity, and impaired Con-A-stimulated splenic T lymphocyte proliferation. Reductions in T splenic cell proliferation and natural killer cytotoxicity were observed in the young rats subjected to the CER paradigm, but not to the same extent as in the old rats. These observations indicate that aging male F344 rats evidence major alterations in basal central monoamine, endocrine and immune functions, and an increased sensitivity of these systems to stress.

Aging↗