Effect of simvastatin on high density lipoprotein subfractions and apolipoproteins in Type IIa hypercholesterolemia

Summary Changes in plasma concentrations of high density lipoproteins (HDL) and triglycerides may partly explain the ability of cholesterol-lowering drugs to decrease the incidence of coronary heart disease. We measured the response of fasting plasma lipids, lipoproteins, and apolipoproteins in 46 subjects with Type IIa hypercholesterolemia treated with simvastatin for 3 months. The initial dose of simvastatin (10 mg/day) was subsequently increased up to 40 mg/day if the plasma cholesterol concentration had not fallen below 5.2 mmol/l. Plasma concentrations of HDL cholesterol and of the apolipoproteins AI and AII were increased by simvastatin. The increase in HDL cholesterol (9%) was due to increases in both subfractions (HDL₂ 17%; HDL₃ 7%), changes that would be consistent with a beneficial effect on cardiovascular risk. Simvastatin decreased plasma triglyceride concentrations by 25%. Plasma total cholesterol concentrations fell by 35% after 3 months of treatment; this fall was proportional to the initial concentration and was due almost entirely to a 45% fall in low density lipoprotein cholesterol. In contrast, plasma concentrations of lipoprotein Lp(a) were not affected by simvastatin.     

皮脂蠕形螨的扫描电镜观察

本文首次报道应用扫描电镜对皮脂蠕形螨某些形态结构进行的观察和描述。发现下列形态结构在两种人体蠕形螨的鉴别上意义较大:除颚体和足体的特异形态外,还包括背基刺、口下板、口孔、足体背面和背足体毛、须跗节上的爪、足爪和末体尾端的皮纹等。根据足节粗壮发达,推测其运动能力较强,足节上的利爪对周围组织可造成一定的损伤。本次观察还描述了雌虫背足体毛,根据背足体毛的形态结构的特点,推测可能是某种化学感受器。     

611例汉族人维生素D受体基因多态性与骨密度关系研究

采用PCR-RFLP分析了611名上海地区汉族人的维生素D受体(VDR)基因型,并测量其骨密度(BMD),统计分析发现男女性VDR基因分布差异存在统计学意义,Bb基因型在男性中的分布频率(26.9%)高于女性(12.7%,P<0.01)。不同基因型的人群BMD差异无统计学意义。     

Lowering of oxidative stress in hemodialysis patients by dialysate cleaning: in relation to arteriosclerosis

The objective of this study was to investigate changes in oxidative stress associated with the cleaning of the dialysate. Thirty-six dialysis patients were studied. Changes in soluble CD-14 (sCD-14), malondialdehyde-low-density lipoprotein (MDA-LDL), and oxidized-LDL (Ox-LDL) were monitored for 1 year before and 1 year after dialysate cleaning. The mean endotoxin (ET) level in the dialysate had previously been confirmed to decrease from 39.0 EU/L to an undetectable level after the cleaning. The mean levels of sCD-14, MDA-LDL, and Ox-LDL decreased significantly after the cleaning (sCD-14, P < 0.0001; MDA-LDL, P < 0.001; Ox-LDL, P < 0.001). One year after the cleaning, six cases still showed high levels of MDA-LDL and Ox-LDL. Cardiovascular events occurred in four of those six cases within 2.8 years after the cleaning. These four patients suffered from strong oxidative stress during dialysis, even after the cleaning. We therefore concluded that high levels of MDA-LDL and Ox-LDL are improved in dialysis patients by cleaning of the dialysate. These results indicate that even a dialysate containing 50 EU/L or less ET may stimulate monocytes and cause oxidative stress. They also suggest that even low levels of ET may aggravate arteriosclerosis in dialysis patients. Thus, in order to prevent cardiovascular events in dialysis patients, it is necessary to purify the dialysate.     

Osteoporosis in children and young adults

Osteoporosis is a major public health problem with serious long-term complications. In children, the definition of osteoporosis is not only based on densitometric criteria but also takes into account vertebral and long bone fragility fractures. Several factors, such as long-term high-dose steroids, chronic inflammation, malnutrition, immobility, lack of sex steroids, and medication can reduce bone density and increase the risk for fragility fractures when left untreated. Also, genetic conditions can predispose to primary bone fragility disorders, with osteogenesis imperfecta being the most common. Furthermore, since the growing skeleton is at an increased rate of bone remodeling, the ability to heal long bone fractures and reshape vertebral fractures differentiates children from adults. The scope of this chapter is to review the risk factors of osteoporosis and fragility fractures and describe the commonest causes of primary and secondary osteoporosis and their management in children and young adults.     

Low bone mineral density in professional scuba divers

Scuba diving is associated with a 90% reduction in effective weight and with the loss of a weight-bearing effect on joints. These conditions are very similar to the continuous weightlessness that occurs in spaceflight and bed-rest, which are clearly associated with significant bone mass loss. Here, we studied the bone mineral density (BMD) of 66 professional scuba divers using a dual-photon densitometer, and have depicted a reduction in the BMD in comparison to a matched control group of non-divers. Our results suggest that diving is also an activity where the unloading effect alters bone metabolism, leading to a reduction in BMD.Abbreviations BMD Bone mineral density     

The fate of electron opaque tracers (horseradish peroxidase and lanthanum chloride) during valproic acid-induced choleresis

ABSTRACT— Horseradish peroxidase (HRP) and lanthanum chloride (LaCl₃) are useful tools for, respectively, the study of vesicular transport through the hepatocyte and the study of the permeability of junctional complexes. These tracers have been used to detect the changes associated with the choleresis independent of bile acids induced by valproic acid (VPA) in rats. The animals were given a single dose of VPA (600 mg/kg, ip). HRP (100 mg/kg) or 5 mM LaCl₃ were given intraportally after 1 h, when bile flow had increased twofold. The excretion of HRP in bile was measured colorimetrically up to 2 h after HRP. Ultrastructural morphometry was conducted on liver of intact rats taken from 1 to 40 min after HRP. The volume density (VD) of HRP-containing vesicles and of HRP-containing multivesicular bodies (MVB) was counted. In VPA-treated rats, HRP appeared in bile with a peak showing at 5 min against 20 min in controls, but the total amount of HRP excreted was less than in controls. The intrahepatocytic vesicular transport of HRP was also modified, showing a peak at 3 min in VPA-treated rats compared to 10 min in controls, together with a decreased VD of pericanalicular vesicles. This was accompanied by an increase of HRP-containing MVB, already evident at 5 min. VPA-induced changes in HRP transport through the hepatocytes appeared twofold: 1) during VPA-induced stimulation of bile flow, there was an early and short-lived increase of transcellular transport and biliary elimination of HRP: 2) a diversion of HRP towards the indirect, lysosomal pathway apparently occurred, in agreement with previous findings concerning the formation of numerous cytolysomes induced by VPA (Hepatology 1984: 4 : 1159–1166). The decreased amount of HRP excreted in bile could be accounted for by a diversion of HRP towards the degradation pathway. The pattern of distribution of LaCl₃ was similar in VPA-treated animals and in controls, suggesting that gross structural alterations of the junctional complexes are unlikely to occur during VPA-induced choleresis.     

SERUM LIPID AND APOLIPOPROTEIN A AND B LEVELS IN FAMILIAL HYPERCHOLESTEROLEMIA

Serum lipid and apolipoprotein A (apo A) and B (apo B) levels were studied in a family with familial hypercholesterolemia (FH), which comprised two heterozygous parents, five heterozygous children, one homozygote and one normal child. Lipid levels were compared with those of age- and sex-matched normal controls. All subjects with FH had total serum cholesterol and low density lipoprotein-cholesterol (LDL-C) levels greater than the 90th percentile value for the reference range. High density lipoprotein-cholesterol (HDL-C) levels were less than the corresponding 13th percentile in heterozygous subjects. The homozygous child had grossly elevated levels of LDL-C and apo B, and very low levels of HDL-C and apo A. The most powerful discriminating variable between normal, heterozygous and homozygous family members was the LDL-C/HDL-C ratio.     

骨质疏松症大鼠骨诱导能力改变的研究

目的　探讨骨质疏松性骨折愈合困难的原因 ,为临床治疗骨质疏松性骨折寻找可行性途径和方法。　方法　雌性SD大鼠 4 0只作为供体大鼠 ,随机分为卵巢切除组和对照组 ,每组 2 0只 ,卵巢切除组切除双侧卵巢以复制骨质疏松模型 ,对照组行假手术。 4个月后处死大鼠 ,取肢体长骨按Urist方法分别制备骨基质明胶。雌性SD大鼠 17只 ,双侧股部切开 ,左、右侧肌袋内分别植入卵巢切除大鼠及对照大鼠骨基质明胶。大鼠饲养 14d处死 ,分别取出肌袋植入物组织行组织学检查及骨碱性磷酸酶 (ALP)活性、Ca含量测定。　结果　卵巢切除组的和对照组的植入物组织ALP活性单位分别为 (7 2 2± 2 5 9)IU/ g和 (12 0 1± 6 18)IU/g ,两者差异有显著性 (P <0 0 1)。卵巢切除组的和对照组的植入物组织Ca含量分别为 (5 10± 0 84 ) μg/ g和 (5 73± 0 79) μg/ g ,两者差异有显著性 (P <0 0 5 )。　结论　雌激素缺失所致骨质疏松骨的骨诱导能力较正常骨明显降低 ,骨质疏松性骨折愈合困难与骨骼中骨诱导生长因子的缺乏有关。对于骨质疏松性骨折的治疗要改进骨折固定方法 ,外源补充或促进内源性骨诱导生长因子的表达 ,对于促进骨折愈合具有重要作用。