Low serum cholesterol and suicidal behavior

An increasing number of studies have shown that low serum cholesterol levels are associated with a risk of suicidal, violent, and impulsive behaviors. This article reviewed the literature on this possible association. Several randomized controlled trials of lowering cholesterol interventions did not reduce total mortality in spite of reduced mortality due to coronary heart disease. This is partly attributable to an increased mortality rate of death due to suicide or accidents among individuals with lowered serum cholesterol. Cohort studies have shown that individuals with low serum cholesterol levels are more likely to present depressive symptoms and suicidal acts in later years than those with higher cholesterol levels. Many studies comparing suicidal and control subjects have found an association between low serum cholesterol and suicidal behavior. Although contradictive results are also reported, further studies are warranted to conclude the possible relationship between low or lowering serum cholesterol and suicidal behavior. Clinicians should be aware of potential effects of lowering cholesterol interventions on behavioral symptoms.     

胆固醇脱氢酶测定血清胆固醇方法的建立

目的 评价胆固醇脱氢酶测定法在临床应用的可行性。方法 胆固醇酯在胆固醇酯酶的作用下，水解为游离胆固醇，后者被胆固醇脱氢酶还原为胆烷-4-烯-3-酮，同时B—NAD^ 还原为β-NADH H^ 。联胺能清除其反应产物胆烷-4-烯-3-酮，使反应完全。结果 回收率为99．9％和100．1％，在1．1～20．28mmol／L内为线性；批内CV为0．29％～0．39％，批间CV为0．42％～0．45％；乳酸脱氢酶无影响；与化学比色法(X1)和胆固醇氧化酶法(X2)比较，回归方程分别为Y=0．992X1—0．006，r=0．997；Y=0．989X2-0．048，r=0．999。结论 本法结果准确、可靠、易自动化。     

胆固醇脱氢酶测定血清胆固醇方法的建立

目的　评价胆固醇脱氢酶测定法在临床应用的可行性。方法　胆固醇酯在胆固醇酯酶的作用下 ,水解为游离胆固醇 ,后者被胆固醇脱氢酶还原为胆烷 4 烯 3 酮 ,同时 β NAD+ 还原为 β NADH +H+ 。联胺能清除其反应产物胆烷 4 烯 3 酮 ,使反应完全。结果　回收率为 99.9%和 10 0 .1% ,在 1.1～ 2 0 .2 8mmol/L内为线性 ;批内CV为 0 .2 9%～ 0 .39% ,批间CV为 0 .4 2 %～ 0 .4 5 % ;乳酸脱氢酶无影响 ;与化学比色法 (X1)和胆固醇氧化酶法 (X2 )比较 ,回归方程分别为Y =0 .992X1- 0 .0 0 6 ,r =0 .997;Y =0 .989X2 - 0 .0 4 8,r =0 .999。结论　本法结果准确、可靠、易自动化。     

Endpoint colorimetric method for assaying total cholesterol in serum with cholesterol dehydrogenase

BACKGROUND: Various methods are available to measure serum cholesterol concentrations. Of these, the cholesterol ester hydrolase (CEH)-cholesterol oxidase-peroxidase chromogenic method is widely used. However, this method has the disadvantage of interference by reducing substances. We developed and evaluated an endpoint assay for serum cholesterol, based on a CEH-cholesterol dehydrogenase (CDH)-ultraviolet method. METHODS: Cholesterol esters are first hydrolyzed to free cholesterol by CEH. The free cholesterol is then reduced by CDH to cholest-4-ene-3-one with the simultaneous production of beta-NADH from beta-NAD(+). At equilibrium, the CDH reaction gives incomplete conversion of cholesterol to cholest-4-ene-3-one. To overcome this disadvantage, we added hydrazine monohydrate to the reaction mixture to remove cholest-4-ene-3-one, which allowed the reaction to proceed to completion and gave stoichiometric production of beta-NADH from the reaction of beta-NAD(+) with cholesterol. RESULTS: We tested whether the amount of cholesterol added was equivalent to the absorbance change of NADH at 340 nm with six aqueous samples. Recoveries were 97.1-100.3%. The reaction was linear up to 20.28 mmol/L. The mean within-day (n = 20) and between-day (n = 10) imprecision (CV) was 0. 29-0.43% and 0.22-0.61%, respectively. No interference by bilirubin, hemoglobin, ascorbic acid, and other reducing agents was observed. The equation obtained in comparison with the modified Abell-Levy-Brodie-Kendall method was: y = 0.992x - 0.0058 mmol/L; r = 0.997; S(y|x) = 0.117 mmol/L; n = 50. CONCLUSION: This method is an accurate, reliable method for serum cholesterol analysis and is amenable to automation.     

Low serum level of high-density lipoprotein cholesterol is a poor prognostic factor for severe sepsis

OBJECTIVE: To assess the initial serum levels of lipids and lipoproteins and their correlations with the clinical outcome for patients with severe sepsis. The ability of high-density lipoprotein (HDL) to attenuate lipopolysaccharide (LPS)-induced cytokine production was also examined in vitro. DESIGN: Prospective, observational cohort study. SETTING: Medical intensive care unit (ICU) of a tertiary-level university hospital. PATIENTS: Sixty-three consecutive patients with severe sepsis. INTERVENTIONS: Blood samples were drawn within the first day of severe sepsis and the subsequent 14 days. Clinical outcome, including length of ICU stay, infection subsequent to hospital stay, and death, were monitored prospectively. MEASUREMENTS AND RESULTS: Compared with the survivors, patients who died within 30 days had significantly lower levels of HDL cholesterol and apolipoprotein A-I during the first 4 days of severe sepsis. On day 1, HDL cholesterol levels correlated inversely with interleukin-6 (r = -0.72; p < .01) and tumor necrosis factor (TNF)-alpha (r = -0.70; p < .01) concentrations. Not only the overall and sepsis-attributable 30-day mortality rates but also the risk of prolonged ICU stay (>7 days) and the hospital-acquired infection rate were increased among patients with day 1 levels of HDL cholesterol of <20 mg/dL and apolipoprotein A-I of <100 mg/dL. Multivariate analysis identified an HDL cholesterol level of <20 mg/dL on day 1 (odds ratio, 12.92; 95% confidence interval, 2.73-61.29) and Acute Physiology and Chronic Health Evaluation II score (odds ratio, 1.15; 95% confidence interval, 1.04-1.26) as independent predictors of the overall 30-day mortality rate. In human macrophages, LPS-induced TNF-alpha release was attenuated by incremental doses of HDL cholesterol added simultaneously (p < .01). However, HDL failed to suppress LPS-induced TNF-alpha production when administered after macrophages were exposed to LPS. CONCLUSIONS: A low HDL cholesterol level on day 1 of severe sepsis is significantly associated with an increase in mortality and adverse clinical outcomes. In cultured macrophages, HDL can attenuate LPS-induced TNF-alpha production only if added concomitantly with, but not after, LPS exposure.     

Low levels of serum cholesterol and systolic blood pressure in Japanese with the apolipoprotein E3/2 genotype.

Apolipoprotein E (apoE) plays an important role in lipoprotein and cholesterol metabolism. An association between serum cholesterol and blood pressure has been suggested by epidemiological and experimental studies. But it is still not clear whether the apoE polymorphism plays a role in regulating blood pressure. The present study was undertaken to determine the association among apoE genotype, serum cholesterol and blood pressure in 303 healthy Japanese workers. Amplified fragments of DNA by the polymerase chain reaction were digested with HhaI and analyzed by 3% agarose-gel electrophoresis. Individuals with the apoE3/2 genotype had significantly lower levels of total cholesterol and systolic blood pressure than either the apoE3/3 individuals or the apoE3/4 + 4/4 individuals (P <0.05). The hypothesis that apoE indirectly influences systolic blood pressure through total serum cholesterol was supported by a covariance analysis of linear structural equations.     

Amperometric determination of total cholesterol in serum, with use of immobilized cholesterol ester hydrolase and cholesterol oxidase.

We describe an electrochemical method for simple, rapid, and economical assay of total serum cholesterol with use of immobilized cholesterol esterase (EC 3.1.1.13) and cholesterol oxidase (EC 1.1.3.6). A rotating porous cell was specially designed to hold the immobilized enzymes firmly and to allow the reaction mixture to pass through the enzyme layer easily, thus catalyzing the enzymatic transformation quickly. Hydrogen peroxide resulting from a catalytic reactions was measured amperometrically at +0.60 V cs. a standard calomel electrode. The calibration curve for total serum cholesterol was linear from 0 to 5.00 g/liter. The method is specific, precise, and inexpensive. Our results correlate well with those obtained by the method of Abell et al. [Stand. Methods Clin. Chem. 2, 26 (1958)], the correlation coefficient being 0.992. Ascorbic acid or bilirubin in concentrations up to 700 mg/liter do not interfere. The immobilized enzymes are stable, and the same immobilized-enzyme stirrer can be used for at least 200 accurate, reproducible assays.     

Correlation between the ratio of serum low-density lipoprotein cholesterol and high-density lipoprotein cholesterol with that of serum apolipoproteins B and A-I

Summary Phosphowolframate/magnesium chloride, a commonly used precipitation method for the determination of high-density lipoprotein cholesterol in human serum, yields a supernatant containing almost all of the lipoproteins apo A-I and apo A-II but no lipoprotein apo B. The correlation between high-density lipoprotein cholesterol and apo A-I was very high (r=0.94), as well as that between the precipitation method and ultracentrifugal analysis (r>0.95,P<0.001). In contrast, detergent precipitation (for the determination of low-density lipoprotein cholesterol in human serum) produced sediments which contained the major proportion of apo B and only minor amounts of apo A-I and apo A-II. The precipitation method for low-density lipoprotein cholesterol showed very good agreement with ultracentrifugal analysis (r=0.99). Yields of 80.2% were obtained for apo B with both methods. Results obtained using the precipitation methods showed excellent agreement with those obtained using the Friedewald formula (r>0.99). Results were also very similar when hypertriglyceridemic serum samples were briefly centrifuged before analysis of cholesterol, high-density lipoprotein cholesterol and triglyceride values. The present study shows highly significant correlations between cholesterol/high-density lipoprotein cholesterol or low-density lipoprotein cholesterol/high-density lipoprotein cholesterol and apo B/apo A-I ratios (P<0.001). Apo B and apo A-I levels could be used in addition to low- and high-density lipoprotein cholesterol values when assessing the risk of cardiovascular disease, if the methods for determining serum apolipoproteins have been properly standardized.     

瘦素、脂代谢与胆固醇结石形成的相关性

目的通过对胆固醇结石患者血清瘦素及血脂成分浓度的测定,旨在探讨瘦素(LP)在胆固醇结石形成中的作用。方法收集兰州医学院第二附属医院普外科胆结石住院患者,确定22例作为实验组(胆石组),其中男10例,女12例。术后通过肉眼观察和化学检测证实为胆固醇结石。患者术前进行各项检查排除心、肝、肾等器官病变,且无高血压、糖尿病、肝炎等慢性病变,不伴或伴胆囊炎但非急性发作者。另外,随机抽取本院经体检及生化全项检查无血脂增高及其他明显病变的健康人群16例,其中男8例,女8例,作为对照组。用生化法检测胆固醇结石组患者及对照组血清总胆汁酸(TBA)、总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)、载脂蛋白的含量;并测身高、体重、腰围,计算体重指数(BMI)、体表面积;用放免法测血清瘦素值。结果胆石组和对照组血脂成分差异具有显著意义。HDL:胆石组为(1.21±0.27)mmol/L,对照组为(1.5±0.3)mmol/L,结石组比对照组低,差异具有显著性意义(t=2.21,P<0.05);血清胆固醇:胆石组为(4.6±0.7)mmol/L,对照组为(4.0±1.0)mmol/L,差异具有显著性意义(t=2.40,P<0.05);载脂蛋白A1(apo-a1):胆石组为(1.28±0.28)g/L,对照组为(1.53±0.25)g/L,差异也具有显著性意义(t=2.56,P<0.05)。胆石组血清瘦素含