DNA polymorphism at the apolipoprotein B locus is associated with lipoprotein level

A strong association has been uncovered between DNA variation at the apolipoprotein B (apoB) locus (detectable with the restriction endonuclease XbaI) and apoB level. The findings are suggestive of associations also between this DNA polymorphism and total cholesterol as well as fasting triglyceride levels, confirming recent results reported by British workers. The data suggest that lipid/apolipoprotein associations with the XbaI polymorphism are primarily caused by an effect on apoB level. In the present and in a previously reported study we found a strong association between the XbaI polymorphism and the homospecific Ag antigenic variation in low density lipoprotein (LDL) which had previously exhibited associations with lipid levels. The present data indicate that the apoB/lipid associations of the Ag and XbaI polymorphisms may reflect the same phenomenon. The associations reported could reflect variation in an apoB domain close to Ag as well as to the XbaI restriction site that is of importance for lipid binding by apoB. Alternatively, the association of apoB level with the XbaI polymorphism (which reflects a silent third base mutation in a threonine codon) could reflect phenomena related to codon usage.     

血脂、颈动脉粥样硬化与缺血性脑血管病的关系

目的：探讨血脂、颈动脉粥样硬化与缺血性脑血管病的关系。方法：2001年6月-2004年12月在佛山市第一人民医院诊治的缺血性脑血管病患者为病例组，共1583例，其中男性902例（57．0％），女性681例（43．0％），年龄38～89岁，平均（60．02±10．35）岁；同时期保健科随机选取的400名健康体检人群作为对照组。将动脉粥样硬化斑块分为稳定型和不稳定型。记录血脂和颈动脉粥样硬化情况并进行对比分析。结果：Logistic回归分析表明，颈动脉斑块与年龄、高血压史和胆固醇水平有显著相关性。有高血压、糖尿病、血浆低密度脂蛋白-胆固醇（LDL-C）水平增高和吸烟史的患者，颈动脉狭窄发生率显著增高。病例组总胆固醇、三酰甘油和LDL-C与对照组有显著差异。缺血性脑血管病患者颈动脉粥样硬化发生率显著高于普通人群。结论：血脂异常和颈动脉粥样硬化是缺血性脑血管病的重要因素。     

Regional heterogeneity in astrocyte responses following contusive spinal cord injury in mice

Astrocytes and their precursors respond to spinal cord injury (SCI) by proliferating, migrating, and altering phenotype. This contributes to glial scar formation at the lesion border and gliosis in spared gray and white matter. The present study was undertaken to evaluate astrocyte changes over time and determine when and where interventions might be targeted to alter the astrocyte response. Bromodeoxyuridine (BrdU) was administered to mice 3 days after SCI, and cells expressing BrdU and the astrocyte marker, glial fibrillary acidic protein (GFAP), were counted at 3, 7, and 49 days post‐injury (DPI). BrdU‐labeled cells accumulated at the lesion border by 7 DPI and approximately half of these expressed GFAP. In spared white matter, the total number of BrdU+ cells decreased, while the percentage of BrdU+ cells expressing GFAP increased at 49 DPI. Phenotypic changes were examined using the progenitor marker nestin, the radial glial marker, brain lipid binding protein (BLBP), and GFAP. Nestin was upregulated by 3 DPI and declined between 7 and 49 DPI in all regions, and GFAP increased and remained above naïve levels at all timepoints. BLBP increased early and remained high along the lesion border and spared white matter, but was expressed transiently by cells lining the central canal and in a unique population of small cells found within the lesion and in gray matter rostral and caudal to the border. The results demonstrate that the astrocyte response to SCI is regionally heterogeneous, and suggests astrocyte populations that could be targeted by interventions. J. Comp. Neurol. 518:1370–1390, 2010. © 2009 Wiley‐Liss, Inc.     

Comparison of two twice-daily insulin regimens: Ultralente/soluble and soluble/isophane

Summary The relative efficacy of two twice-daily insulin regimens using highly purified insulins, once daily Ultratard with twice daily Actrapid (ultralente/soluble) and twice daily Actrapid with twice daily Retard (soluble/isophane), has been studied in 12 diabetics in a cross-over study. Control was optimised as an out-patient, and assessed by in-patient 24 hour profiles. Similar day-time glucose control was achieved, but the mean overnight plasma glucose concentrations were more steady on ultralente/soluble (0100, 0300, 0500, 0700, 0800 h values 5.6, 5.3, 5.8, 7.8, 10.4 mmol/l) than on soluble/isophane (4.3, 3.4, 5.2, 7.5, 12.2 mmol/l). The minimum overnight plasma glucose concentrations were lower (p < 0.05) on soluble/isophane (mean 2.8 mmol/l) than on ultralente/soluble (mean 4.8 mmol/l), associated with higher (p < 0.05) nocturnal free plasma insulin levels after the evening soluble/isophane injection. The plasma glucose rise between 0700 and 0800 h was greater (p < 0.05) on soluble/isophane than on ultralente/soluble. The morning insulin injection should probably be taken immediately on rising, to prevent the pre-breakfast plasma glucose rise. The ultralente/ soluble combination gave similar day-time plasma glucose control to soluble/isophane with less nocturnal hypoglycaemia.     

The effects of a low-dose intravenous insulin infusion upon plasma glucose and non-esterified fatty acid levels in very obese and non-obese human subjects

Summary After an overnight fast, the effects of a 30-min low-dose intravenous insulin infusion (2.6 units/h) upon plasma glucose and non-esterified fatty acids were compared in 29 very obese patients and 17 nonobese controls. The dose of insulin was chosen so as to have its sole or predominant hypoglycaemic effect upon hepatic glucose release. The proportional fall from basal values at 30 min of both plasma glucose and non-esterified fatty acids was significantly greater in the controls and there was no difference between males and females. In the controls the fall in plasma glucose and non-esterified fatty acids was significantly and inversely correlated with the basal plasma insulin level. Neither index of insulin sensitivity was significantly related with the basal plasma insulin in the obese subjects. Weight loss in the obese subjects led to increased insulin sensitivity; in particular, the degree of change in insulin-induced nonesterified fatty acids was significantly related to the percentage change in weight. Despite their extreme degree of obesity, the distributions of basal plasma insulin levels and the indices of insulin sensitivity in the obese subjects overlapped with those of the nonobese controls.     

Flow cytometric detection of endothelial microparticles (EMP): Effects of centrifugation and storage alter with the phenotype studied

Introduction

Endothelial microparticles (EMP) are released into the circulation in case of endothelial disturbance, and are therefore increasingly investigated as a biomarker reflecting disease activity. Numerous pre-analytic methods have been proposed for their flow cytometric enumeration, but standardization is still lacking. In this study we evaluated the influence of centrifugation and storage conditions on EMP quantification.

Materials and Methods

Platelet-poor plasma (PPP) from 10 healthy volunteers was prepared by centrifugation at 1 550 g for 20 minutes twice. A first aliquot of PPP was analyzed immediately, a second after storage at 4 °C for 7 hours. A third and fourth aliquot were snap-frozen and stored at -80 °C for 7 and 28 days. A final aliquot was further centrifuged at 10 000 g for 10 minutes and analyzed immediately. EMP were defined as CD31+CD42b-, CD62E+, CD144+ or CD144+CD105+ particles, smaller than 1.0 µm.

Results

High speed centrifugation led to a significant loss of CD31+CD42b- EMP (p = 0.004). A good correlation between PPP and high speed centrifuged PPP was only found for CD144+ EMP (Kendall tau b = 0.611, p = 0.025).Storage at 4 °C did not affect EMP quantification. However, freezing at -80 °C increased CD31+CD42b- and CD62E+ EMP counts, and lowered CD144+ EMP (p < 0.05). Nevertheless, the agreement among the different storage conditions was relatively good (Kendall coefficient of concordance > 0.487; p < 0.05).

Conclusion

The flow cytometric detection of EMP varies with the centrifugation protocol and the storage method used, and these changes also depend on the phenotype studied. The results of this study caution against comparing study results gathered with different EMP laboratory protocols.     

Overexpression of aldehyde dehydrogenase 1A1 reduces oxidation‐induced toxicity in SH‐SY5Y neuroblastoma cells

Oxidative stress leading to lipid peroxidation is a problem in neurodegenerative diseases, because the brain is rich in polyunsaturated fatty acids and low in endogenous antioxidants. One of the most toxic byproducts of lipid peroxidation, 4‐hydroxynonenal (HNE), is implicated in oxidative stress‐induced damage in neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). In this study, the human neuroblastoma cell line SH‐SY5Y was used to test the protective effects of increasing the detoxification of HNE by overexpressing the HNE‐detoxifying enzyme aldehyde dehydrogenase 1A1 (ALDH1). Overexpression of ALDH1 in the SH‐SY5Y cells acts to reduce production of protein–HNE adducts and activation of caspase‐3. Our data suggest that detoxification of HNE could be therapeutic in preventing some of the toxic disruptions of the brain's redox systems found in many neurodegenerative diseases. © 2009 Wiley‐Liss, Inc.     

A possible role of myristoylated alanine-rich C kinase substrate in endocytic pathway of Alzheimer’s disease

It is believed that amyloid-β peptide (Aβ) plays a central role in the pathogenesis of Alzheimer’s disease (AD). Thus, the process of amyloid precursor protein (APP) cleavage is a key event and has raised much attention in the field of AD research. It is proposed that APP, β- and γ-secretases are all located on the lipid raft, and the meeting of them is an indispensable step for Aβ generation. Endocytosis can lead to clustering of APP, β- and γ-secretases from separate smaller lipid rafts into a larger one. On the other hand, for myristoylated alanine-rich C kinase substrate (MARCKS), phosphorylation by protein kinase C (PKC) or interaction with Ca²⁺ can lead to its release from membrane into cytoplasm. This process induces the release of actins and phosphatidylinositol 4, 5-bisphosphate (PIP₂), which are important factors for endocytosis. Thus, the present review proposes that MARCKS may be implicated in Aβ generation, by modulating free PIP₂ level and actin movement, causing endocytosis.     

Plasma levels of soluble receptor for advanced glycation end products in Alzheimer's disease

Background: A decreased plasma level of soluble form of the receptor for advanced glycation end products (sRAGE) in patients with Alzheimer's disease (AD) has been reported. However, no evidence has shown whether the sRAGE plasma level of AD patients may differentiate from other types of dementia. Methods: Our study assessed sRAGE concentrations in the following 121 individuals in Chongqing area: 36 patients with AD, 12 with vascular dementia (VaD), 14 with mixed dementia (MD), 24 with other dementia (OD) including Parkinson's disease dementia, frontotemporal dementia, paralytic dementia and 35 cognitively normal controls. The total plasma level of sRAGE was determined using sandwich ELISA method. Results: sRAGE concentration in AD is significantly decreased compared with healthy controls. However, the receiver operating characteristic curve analysis of sRAGE between the AD and the control shows a low diagnostic accuracy. Conclusions: Our results demonstrate that sRAGE may assist the diagnosis of AD from normal individuals, but cannot differentiate AD from VaD, MD or OD.