α2－巨球蛋白活性检测方法的建立与优化

目的：建立α2－巨球蛋白（α2－macroglobulin ,α2－M）活性检测方法,检测Cohn组分Ⅳ中α2－M的活性。方法α2－M可与胰蛋白酶相互作用形成“α2－M－胰蛋白酶复合物”,利用酶标仪检测出“α2－M－胰蛋白酶复合物”与小分子底物Na－苯甲酰－DL－精氨酸－对硝基酰胺盐酸盐（ Na－benzoyl－DL－arginine 4－nitroanilide hydrochloride ,BAPNA）显色反应后的光密度值（410 nm）,根据建立的血浆α2－M活性标准曲线,定量计算出Cohn组分Ⅳ浓缩液中α2－M的活性。结果通过对实验体系中几个关键实验条件进行优化,建立了血浆α2－M活性标准曲线,并计算出Cohn组分Ⅳ浓缩液中α2－M活性的平均值为1．578 PU／ml。结论以正常人混合血浆作为参考标准品,用发色底物法检测Cohn组分Ⅳ浓缩液中α2－M的活性,方法简便易行,为α2－M制备过程中活性测定提供了实验基础。     

Selective acquisition of plasma proteins by Trichomonas vaginalis and human lipoproteins as a growth requirement for this species

Trichomonas vaginalis avidly bound numerous host macromolecules which were not removed by repeated washing in phosphate buffered saline. The use of radioiodinated Cohn plasma fractions in binding studies allowed the identification of plasminogen, fibrinogen, immunoglobulin G, lipoproteins A and B, transferrin, α₁-antitrypsin, and albumin on intact organisms. The binding of immunoglobulin G, albumin, transferrin, and lipoproteins to intact, motile trichomonads was further demonstrated using ¹²⁵I-labeled plasma that was chromatographically depleted of these proteins. Kinetic studies indicated that ¹²⁵I-labeled lipoproteins bind to T. vaginalis in a receptor-ligand-like manner. The surface localization and uptake of bound lipoproteins was shown by treatment of intact organisms with pronase at various times after incubation with lipoproteins. Purified lipoproteins could be substituted for plasma or serum as a growth supplement in a complex medium of trypticase/yeast extract/maltose and supported growth and multiplication rates equal to those in the same medium with plasma.     

Value of a noninvasively induced ventricular extrasystole during echocardiographic and phonocardiographic assessment of patients with idiopathic hypertrophic subaortic stenosis

Fifteen patients with idiopathic hypertrophic subaortic stenosis had a ventricular extrasystole induced with a new external mechanical cardiac stimulator during noninvasive evaluation of left ventricular outflow tract obstruction. Ten patients were monitored with simultaneous echocardiogram, phonocardiogram and indirect carotid pulse tracing; five were monitored with the phonocardiogram and indirect carotid pulse tracing alone. Nine of the 15 patients showed obstruction in the beat after the ventricular extrasystole, as defined by appearance of the characteristic bifid carotid pulse contour and, where recorded, an increase in systolic anterior motion of the mitral valve on echocardiography. Six patients did not show obstruction. All nine patients with obstruction had greater than 20 msec prolongation of uncorrected systolic ejection time in the post-extrasystolic beat of the carotid pulse tracing. Change in the uncorrected ejection time was + 0.038 ± 0.015 second (mean ± standard deviation) in these nine patients compared with − 0.003 ± 0.005 second in the six not showing obstruction (P < 0.01). Six patients underwent cardiac catheterization: Three patients without obstruction after a noninvasively induced ventricular extrasystole had no obstruction at catheterization and three patients with obstruction after noninvasively induced ventricular premature beats demonstrated obstruction at rest or after provocative maneuvers during catheterization. These results indicate that the noninvasive induction of a ventricular extrasystole is a useful and easily performed procedure for both diagnosing and evaluating the dynamic left ventricular outflow tract obstruction of idiopathic hypertrophic subaortic stenosis.     

Global and regional left ventricular ejection fraction abnormalities during exercise in patients with silent myocardial ischemia

Sixteen asymptomatic patients with coronary artery disease and silent myocardial ischemia were studied with exercise radionuclide ventriculography. Radionuclide ventriculograms were analyzed for changes in ejection fraction globally and in three regions. Results were compared with radionuclide ventriculograms in 24 symptomatic patients. Both groups (silent myocardial ischemia and angina) were similar in prevalence of multivessel disease and previous myocardial infarction, as well as in age and sex. Global ejection fraction decreased by 0.06 in both groups during exercise; regional ejection fraction also decreased by similar amounts in the two groups. Furthermore, the percent of regions with normal ejection fraction at rest that demonstrated a decrease during exercise was identical: 19 (60%) of 33 versus 26 (60%) of 46. These exercise radionuclide ventriculographic results suggest that abnormalities in regional and global left ventricular wall motion are similar in patients with coronary artery disease with and without silent myocardial ischemia.     

Prognostic importance of anginal symptoms in angiographically defined coronary artery disease

To evaluate the prognostic importance of anginal symptoms, 44 patients with angiographically defined coronary artery disease and no anginal symptoms at time of cardiac catheterization were selected from the Duke Harvard Collaborative Data Bank. They were “matched” with 127 symptomatic patients in the Data Bank who had similar coronary anatomy and ventricular function. Follow-up data indicated that the patients without anginal symptoms had a significantly better prognosis over a 7 year period than did those with symptoms: Annual mortality in the asymptomatic group was 2.7 percent compared with 5.4 percent in the group with angina (p 0.05). Although the patient population was a highly selective one and the matching categories were relatively broad, these results suggest that the presence of anginal symptoms may be an important independent correlate of prognosis in patients with coronary artery disease. The absence of angina did not preclude the presence of multivessel disease and did not necessarily imply a benign prognosis, because the yearly mortality rate was nearly 5 percent in the subgroup of asymptomatic patients with three vessel disease.