The J-curve relationship of treated diastolic blood pressure to mortality risk: Is it real? Is it clinically meaningful?

Low diastolic blood pressure is alleged to impose excess cardiovascular disease (CVD) risk in patients with treated hypertension, impeding aggressive reduction of blood pressure. Most investigations that assessed the potential J-shaped relations of diastolic blood pressure and adverse outcomes have not adequately considered systolic or pulse pressure in statistical analyses. An overview of hypertension trials indicates that lowering elevated blood pressure reduces the risk of CVD outcomes irrespective of the associated decrease in diastolic pressure, even if the achieved diastolic pressure averages less than 70 mm Hg. The Framingham study investigations have determined that the increased CVD incidence observed at low diastolic blood pressure levels is confined largely to persons with concomitantly increased systolic pressure. This finding of no true excess risk at low diastolic blood pressure agrees with the results of trials that have evaluated the J-curve phenomenon adjusting for systolic pressure. Aggressively treating systolic hypertension appears to produce no cause for alarm.     

Status of risk factors and their consideration in antihypertensive therapy

Risk factors for cardiovascular disease include atherogenic personal attributes, living habits that promote them, signs of preclinical disease and host susceptibility. Atherogenic traits include the blood lipids, blood pressure and glucose tolerance. An increased low density lipoprotein cholesterol level is positively related, and an increased high density lipoprotein cholesterol level is inversely related, to cardiovascular disease incidence. Hypertension, whether systolic or diastolic, labile or fixed, casual or basal, at any age in either sex contributes greatly. The impact of diabetes is greater for women than men and varies depending on the level of the foregoing risk factors. An atherogenic lifestyle is typified by a diet excessive in calories, fat and salt, sedentary habits, unrestrained weight gain and smoking. Alcohol used in moderation may be beneficial. Oral contraceptives worsen atherogenic traits and, when used for long periods beyond age 35 and in conjunction with cigarettes, predispose to thromboembolism. Type A persons with an overdeveloped sense of time urgency, drive and competitiveness develop an excess of angina pectoris. Men married to more highly educated women are at increased risk as are men married to women in white collar jobs. Preclinical signs of compromised coronary circulation include silent myocardial infarction, left ventricular hypertrophy on the electrocardiogram, blocked intraventricular conduction and repolarization abnormalities. An electrocardiogram obtained during exercise may elicit still earlier evidence. Measures of innate susceptibility include a family history, history of premature cardiovascular disease, diabetes, hypertension and gout. Optimal prediction of risk requires a quantitative combination of risk factors in multiple logistic risk formulations to identify high risk persons with multiple marginal abnormalities.     

Hyperuricemia as a risk factor of coronary heart disease: The Framingham Study

Uric acid values were obtained on subjects of the original Framingham cohort at their fourth and 13th biennial examinations. The mean uric acid value for men was 5.0 mg/dl at the fourth examination and 5.7 mg/dl at examination 13 and was 3.9 mg/dl and 4.7 mg/dl, respectively, for women. This secular trend was due to both "laboratory drift" and increasing use of diuretics. Serum uric acid values were consistently higher in subjects of both sexes who were taking antihypertensive drugs at both examinations. Serum uric acid values correlated with systolic and diastolic blood pressure in both sexes; the relationship was stronger in women than in men and for systolic than for diastolic pressure. Correlations were stronger at examination 4 than at examination 13 when more antihypertensive treatment was used. Examination 4 serum uric acid predicted the subsequent development of coronary heart disease, in general, and myocardial infarction, in particular, but not angina pectoris. The uric acid relationship with myocardial infarction was equally strong in both sexes, even correcting for antihypertensive treatment. However, in multivariate analysis, including age, systolic blood pressure, relative weight, cigarette smoking, and serum cholesterol, serum uric acid did not add independently to the prediction of coronary heart disease.     

Beckman EL-ISE电解质分析仪准确性及故障的分析判断

0 引言为了克服离子选择电极（ISE）法的微量电位信号极易受环境温度变化及电子噪声的干扰问题,该仪器采用了参考电极,把参考电极与其测定电极装在同一测量室内,保持其相同的物理环境,使干扰源对所有电极的影响相同. 以内参液作为参考电极的测量对象,测得一个参考电极电位值,再测样品的电极电位值,二者相抵就消除了所叠加的干扰信号.