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Biomedical subjects

C Buck

Publications and source records attributed to C Buck.

At least 73 records · Page 4Linked to original sources
PubMed1985

The cell substrate attachment (CSAT) antigen has properties of a receptor for laminin and fibronectin.

The cell substrate attachment (CSAT) antigen is an integral membrane glycoprotein complex that participates in the adhesion of cells to extracellular molecules. The CSAT monoclonal antibody, directed against this complex, inhibited adhesion of cardiac and tendon fibroblasts and skeletal myoblasts to both laminin and fibronectin, thus implicating the CSAT antigen in adhesion to these extracellular molecules. Equilibrium gel filtration was used to explore the hypothesis that the CSAT antigen functions as a cell surface receptor for both laminin and fibronectin. In this technique, designed for rapidly exchanging equilibria, the gel filtration column is pre-equilibrated with extracellular ligand to ensure receptor occupancy during its journey through the column. Both laminin and fibronectin formed complexes with the CSAT antigen. The association with laminin was inhibited by the CSAT monoclonal antibody; the associations with both fibronectin and laminin were inhibited by synthetic peptides containing the fibronectin cell-binding sequence. Estimates of the dissociation constants by equilibrium gel filtration agree well with those available from other measurements. This suggests that these associations are biologically significant. SDS PAGE showed that all three glycoproteins comprising the CSAT antigen were present in the antigen-ligand complexes. Gel filtration and velocity sedimentation were used to show that the three bands comprise and oligomeric complex, which provides an explanation for their functional association. The inhibition of adhesion by the CSAT monoclonal antibody and the association of the purified antigen with extracellular ligands are interpreted as strongly implicating the CSAT antigen as a receptor for both fibronectin and laminin and perhaps for other extracellular molecules as well.

Animals↗
PubMed1985

Isometric occupational exercise and the incidence of hypertension.

The effect on blood pressure of regular exposure to isometric exercise was studied by measuring the incidence of hypertension among 4,273 men classified according to occupational isometric activity. Incidence of hypertension was lower among men in jobs with moderate or heavy isometric activity. This difference persisted after statistical adjustment for age, social class, obesity, and use of alcohol.

Adult↗
PubMed1984

Extracellular matrix and capillary ingrowth in interspecies chimeric kidneys.

The migration of capillaries into mouse embryonic kidneys grafted on quail chorioallantoic membrane (CAM) was analyzed by two monoclonal antibodies against quail endothelial and haematopoietic cells. As shown by immunohistochemistry, the quail chorioallantoic vessels invaded the kidney explant. Initially, the capillaries were detected in the interstitial stroma and, soon thereafter, tightly adjacent to the branches of the ureteric bud. The induced mesenchymal cell condensates, the prospective nephric vesicles, were avascular, but when the early S-shaped body was formed, the capillaries invaded its lower crevice. Finally chimeric glomeruli consisting of mouse podocytes and quail endothelial cells, were formed and, contemporarily, the capillaries ceased to migrate. Within the endothelial-mesangial area of the chimeric glomeruli, all cells expressed the quail-type nuclear structure and were stained by the quail endothelial-specific antibodies. The pattern of migrating capillaries was compared to the distribution of the extracellular matrix (ECM) molecules by double staining with polyclonal antibodies against laminin or fibronectin, and monoclonal quail endothelial-specific antibodies. Initially, the capillaries migrated in a fibronectin-rich matrix, devoid of laminin, but when the epithelial kidney tubules formed, some capillaries attached to the newly formed epithelial basement membrane. At no stage were the capillaries seen to penetrate the epithelial basement membrane. The orderly branching of the ureteric bud, followed by the formation of nephrons and the shift in the ECM, might create pathways for an oriented capillary migration. The fibronectin-rich areas could be a scaffold for the capillary migration, and the attachment to the basement membranes a means for their cessation.

Animals↗
PubMed1982

A monoclonal antibody detaches embryonic skeletal muscle from extracellular matrices.

We have described a monoclonal antibody that rounds and detaches chick skeletal myoblasts and myotubes from extracellular substrata. The antibody also inhibits the attachment of myogenic cells to a gelatin-coated substratum but has no detectable effect on myoblast fusion. The cellular response to antibody treatment varies with differentiation and cell type. Young myoblasts and myotubes are rapidly rounded and detached by the antibody. Older myotubes require longer incubation times or higher antibody titers for rounding and detachment. Chick embryo fibroblasts, cardiac cells, and neurons are not similarly rounded and remain attached. Since the antibody also detaches cells from embryonic muscle tissue explants, the cell-substratum interaction perturbed by the antibody appears relevant to the in vivo interaction of myogenic cells with their extracellular matrices. Binding studies using iodinated antibody revealed 2-4 x 10(5) sites per myoblast with an apparent Kd in the range of 2-5 x 10(-9) molar. Embryo fibroblasts bind antibody as well and display approximately twice the number of binding sites per cell. The fluorescence distribution of antigen on myoblasts and myotubes is somewhat punctate and particularly bright along the edge of the myotube. The distribution on fibroblasts was also punctate and was particularly bright along the cell periphery and portions of stress fibers. For both cell types the binding was distinctly different than that reported for collagen, fibronectin, and other extracellular molecules. The antigen, as isolated by antibody affinity chromatography, inhibits antibody-induced rounding. SDS PAGE reveals two unique polypeptides migrating in the region of approximately 120 and 160 kilodaltons (kd). The most straightforward mechanism for the antibody-induced rounding and detachment is the perturbation of a membrane molecule involved in adhesion. The hypothesized transmembrane link between extracellular macromolecules and the cytoskeleton provides an obvious candidate.

Animals↗
PubMed1982

Infant diarrhoea and subsequent mortality from heart disease and cancer.

A preliminary examination of the relationship between the infant mortality of US birth cohorts and their mortality in later life suggested that infant mortality from diarrhoea and enteritis was particularly influential. In the 1917-21 birth cohorts of 17 US Registration States, infant mortality from diarrhoea and enteritis was significantly related to arteriosclerosis heart disease at ages 40-44 and 50-54 in both sexes, and to respiratory cancer at the same ages in men, after controlling for contemporary infant mortality. Hypotheses suggest by these relationships are put forward.

Adult↗
PubMed1981

Reasons for dropout from exercise programs in post-coronary patients.

The dropout rate in the 7-yr Ontario Exercise Heart Collaborative Study of post-coronary men engaged in exercise programs was examined in order to determine possible contributing factors. A questionnaire pertaining to psychosocial and program-related variables was distributed to 728 subjects who were previously assigned randomly on the basis of four prognostic risk factors (occupation, personality, hypertension, and angina) into exercise groups: low intensity exercise (LIE), and high intensity exercise (HIE). Comparisons of answers by the 639 respondents (266 dropouts; 373 compliers) were made initially by chi-square analysis to determine significant categories of questions and, subsequently, by a logistic transform to determine the specific questions which related significantly to the dropout rate. It was found that three main categories were associated with a high dropout rate: convenience aspects of the exercise center, perceptions of the exercise program, and family/lifestyle factors. These three main categories should be carefully considered when designing and implementing potential compliance-improving strategies for secondary prevention exercise programs entailing long-term adherence.

Angina Pectoris↗
PubMed1978

Radiotherapy of mycosis fungoides: twenty years of experience with teleroentgen and low-voltage X-ray therapy.

Of 98 patients with mycosis fungoides, 55 have been treated with teleroentgen therapy and 43 with low voltage radiation at a shorter distance. Teleroentgen therapy is indicated in the stage of generalized eczematous lesions or superficial infiltration. According to the Hamburg method, a dose of 300 R was delivered to eight fields at a target distance of 120 cm. After a series of one to three treatments, 300 R, administered at three-week intervals, all lesions usually cleared. Small patches and deeply infiltrated lesions and tumors were treated with the same doses and intervals of low voltage X rays, the half-value depth corresponding to the depth of infiltration. After five years, 54% of all patients were still alive and after 10 years, 29% were still living.

Adult↗
PubMed1978

Season of birth among the sibs of schizophrenics.

The season of birth distribution of 1,039 sibs of Canadian schizophrenic patients was compared with that of births in the Canadian general population over the same time period. The excess of winter births observed among the schizophrenics was not found among their sibs.

Canada↗