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851.
JS Pankow AR Folsom MA Province DC Rao RR Williams J Eckfeldt TA Sellers 《Canadian Metallurgical Quarterly》1998,18(10):1559-1567
Elevated plasminogen activator inhibitor-1 (PAI-1) and fibrinogen concentrations are risk factors for coronary heart disease. We investigated environmental, familial, and genetic influences on PAI-1 antigen and fibrinogen concentrations in 2029 adults from 512 randomly ascertained families in 4 US communities. We used maximum-likelihood segregation analysis to fit several genetic and nongenetic modes of inheritance to the data to determine whether mendelian inheritance of a major gene could best explain the familial distributions of these 2 hemostatic factors. Age- and gender-adjusted familial correlations for PAI-1 antigen level averaged 0.16 in first-degree relatives (95% CI=0.11 to 0.21); the spouse correlation was positive but not statistically significant (r=0.10, 95% CI=-0.02 to 0.23). Complex segregation analysis indicated a major gene associated with higher PAI-1 concentrations in 65% of individuals from these families. Demographic, anthropometric, lifestyle, and metabolic characteristics together explained 37% to 47% of the variation in PAI-1 antigen levels, and the inferred major gene explained an additional 17% of the variance. Positive and statistically significant age- and gender-adjusted familial correlations in first-degree relatives indicated a possible heritable component influencing plasma fibrinogen concentration (r=0. 17, 95% CI=0.13 to 0.22); however, segregation analysis did not provide statistical evidence of a major gene controlling fibrinogen level. These family data suggest that there are modest familial and genetic effects on the concentration of PAI-1. 相似文献
852.
QM Wang F Chen X Luo DC Moore M Flanagan GP Studzinski 《Canadian Metallurgical Quarterly》1998,12(8):1256-1265
Cyclin-dependent kinase inhibitors are proteins with functions which appear to involve regulation of cell cycle traverse, and have been suggested to have a role in cell differentiation. However, there is as yet no rigorous proof that this is the case. We have addressed the participation of one of these inhibitors, p27Kip1, in the induction of differentiation and the subsequent G1 block induced in HL60 cells by 1,25-dihydroxyvitamin D3 (1,25D3). First, it was noted that sublines of HL60 cells able to grow rapidly in the presence of 1,25D3 have protein levels of p27Kip1 lower than the levels in cells subjected to 1,25D3-induced growth inhibition, but higher than in untreated parental cells. In contrast, there was no discernible relationship between the levels of p27Kip1 and the expression of differentiation markers. Further, HL60 cells treated with 1,25D3 and an oligonucleotide antisense, but not mismatched, to p27Kip1 showed an almost complete elimination of the 1,25D3-induced G1 block, but no decrease in the expression of differentiation markers. Similar results were obtained following transient transfection with an expression vector bearing the entire p27Kip1 coding sequence in the anti-sense orientation. This is the first direct demonstration that p27Kip1 plays a role in the 1,25D3-induced G1 arrest, and that partial reduction in its levels has no effect on the induction of differentiation in HL60 cells. 相似文献
853.
854.
DC Rappaport 《Canadian Metallurgical Quarterly》1998,104(5):105-8, 113-4
The past few years have witnessed a massive explosion in clinical applications for computed tomography (CT) as a result of exponential advances in technology. Most clinical practitioners have a limited understanding of the complexities and dynamics of modern CT, and even many radiologists are unable to keep up with the rapid evolution in refinements. In this article, Dr Rappaport summarizes some of the most recent advances in use of helical, or spiral, CT to diagnose diseases of the thorax and abdomen. 相似文献
855.
One of the more stunning examples of the resourcefulness of human vision is the ability to see 'biological motion', which was first shown with an adaptation of earlier cinematic work: illumination of only the joints of a walking person is enough to convey a vivid, compelling impression of human animation, although the percept collapses to a jumble of meaningless lights when the walker stands still. The information is sufficient to discriminate the sex and other details of the walker, and can be interpreted by young infants. Here we measure the ability of the visual system to integrate this type of motion information over space and time, and compare this capacity with that for viewing simple translational motion. Sensitivity to biological motion increases rapidly with the number of illuminated joints, far more rapidly than for simple motion. Furthermore, this information is summed over extended temporal intervals of up to 3 seconds (eight times longer than for simple motion). The steepness of the summation curves indicates that the mechanisms that analyse biological motion do not integrate linearly over space and time with constant efficiency, as may occur for other forms of complex motion, but instead adapt to the nature of the stimulus. 相似文献
856.
857.
J Grünenfelder U Bartram R Van Praagh KE Bove WW Bailey RA Meyer PR Koenig AR Perez DC Schwartz 《Canadian Metallurgical Quarterly》1998,65(6):1790-1791
A rare window type of patent ductus arteriosus is reported that was large (15 mm in maximal transverse dimension) but had virtually no length and hence was externally invisible. The smaller aortic isthmus (4 mm in diameter), which was intrapericardial, was mistaken for the ductus and was inadvertently clip-occluded, leading to death. After a specific diagnosis is made, the large window ductus should be patched on cardiopulmonary bypass with a transpulmonary approach. 相似文献
858.
New findings concerning the molecular mechanisms of nucleotide excision repair (NER) are discussed. 相似文献
859.
Endothelial cells produce C-type natriuretic peptide (CNP), which has been proposed as an endothelium-derived hyperpolarizing factor. In porcine coronary arteries, we investigated the vasodilatory effects of CNP and compared them with endothelium-dependent relaxations and hyperpolarizations to bradykinin. Isolated epicardial porcine coronary arteries were studied in organ chambers, and concentration-response curves to CNP and bradykinin were obtained. Membrane potential was measured in endothelial cells and smooth muscle of intact porcine coronary arteries during stimulation with CNP or bradykinin. In precontracted porcine coronary arteries with or without endothelium, CNP (10[-10]-10[-6] M) evoked relaxations (maximum, 42 +/- 4%) smaller than those evoked by bradykinin (100 +/- 1%), blunted in preparations contracted by KCl instead of U46619 (9,11-dideoxy-11a,9a-epoxymethano-prostaglandin F2alpha; p < 0.05) and unaffected by inhibition of NO synthase (NS). CNP evoked hyperpolarization of vascular smooth muscle of similar magnitude in endothelium-intact (-4.4 +/- 1 mV) and endothelium-denuded (-4.6 +/- 1 mV) porcine coronary arteries. Bradykinin (10[-10]-10[-6] M) evoked concentration-dependent relaxations in preparations with endothelium only. Although atrial natriuretic peptide-receptor antagonist HS-142-1 (25 microM) slightly reduced the sensitivity to bradykinin (log shift at IC50, twofold; p < 0.05), it had no effect on the maximal response to bradykinin. Inhibition of NO synthase partially attenuated, whereas high potassium chloride (30 mM) markedly inhibited relaxations to bradykinin (p < 0.05). Hyperpolarization to bradykinin was much more pronounced than that to CNP (-17 +/- 3 mV; p < 0.05 vs. CNP) and was observed in endothelium-intact preparations only and unaffected by HS-142-1. In conclusion, in contrast to bradykinin, CNP induces endothelium-independent and weaker relaxation and hyperpolarization of coronary artery vascular smooth muscle, suggesting that CNP is an unlikely mediator of endothelium-dependent hyperpolarization of porcine coronary arteries. 相似文献
860.