Effect of beta-amyloid peptide fragment 25-35 on nonselective permeability of mitochondria

Beta-Amyloid peptide fragment 25-35 potentiated phosphate- and calcium-induced opening of mitochondrial channels and caused swelling of mitochondria (even without exogenous calcium and phosphate). These changes were accompanied by accumulation of lipid peroxidation products in mitochondria. Specific inhibitors of mitochondrial channels ADP and cyclosporine A prevented beta-amyloid peptide-induced swelling of mitochondria. Our findings suggest that potentiation of mitochondrial channel opening is an important component of the neurodegenerative effect of beta-amyloid.     

血脂测定结果的临床可接受性分析

目的:通过对不同检测系统血脂测定结果的偏倚评估,分析各系统间结果的可比性和临床可接受性。方法:参照CLSI文件相关要求,以可溯源的检测系统为目标检测系统,测定总胆固醇(TCH)、甘油三酯(TG)、载脂蛋白A1(APOA1)、载脂蛋白B(APOB)、高密度脂蛋白胆固醇(HDL-C)和低密度脂蛋白胆固醇(LDL-C),对本院3个不同检测系统进行朗道质控物(水平2和水平3)各测定21次和测定新鲜血清标本40份。结果:朗道质控物和新鲜血清标本TCH、TG、APOA1、APOB、HDL-C、LDL-C浓度在系统间的差异均有显著性(P<0.05)。除LDL-C在各检测系统间的相关系数为0.7859~0.9259之间外,其他项目各系统间的相关系数均大于0.975。各检测系统测定TCH、TG的不精密度CV均小于5%,其他项目的不精密度CV均小于10%;以可溯源检测系统1为目标检测系统,临床可接受性能评价:TCH、LDL-C在检测系统2和检测系统3超出临床接受范围,HDL-C在检测系统2超出临床接受范围,其他项目临床均可接受。结论:3个不同检测系统测定TG、APOA1、APOB结果具有可比性;测定HDL-C结果具有部分可比性,TCH、LDL-C结果不具有可比性,需采取整改措施。     

大于胎龄儿脐血脂联素水平测定及其临床意义研究

目的探讨血脂联素水平与大于胎龄儿发生的关系。方法研究对象为大于胎龄儿和适于胎龄儿各30例。应用酶联免疫吸附法(ELISA)测定脐血和产妇血脂联素浓度,用免疫比浊法测定甘油三酯(TG)、总胆固醇(TCH)、低密度脂蛋白-胆固醇(LDL-c)、高密度脂蛋白-胆固醇(HDL-c)的水平;并分析脐血脂联素水平与母血脂联素、新生儿性别、出生体重、体重指数、胎盘重量和血脂水平的相关性。结果①大于胎龄儿脐血浆脂联素水平低于适于胎龄儿,差异有非常显著性(P<0.01=;大于胎龄儿血TG、TCH、LDL-c、HDL-c的水平与适于胎龄儿比较差异均无显著性(P>0.05)。②大于胎龄儿血浆脂联素水平与新生儿出生体重、BM I、胎盘重量、脐血TG水平均呈显著负相关(r分别=-0.848、-0.785、-0.835,P均<0.001=,与母血脂联素水平、新生儿身长、孕前和分娩时产妇体重及其BM I、其它脐血脂成分无相关性(P>0.05)。母血脂联素水平与上述因素无相关性(P>0.05)③大于胎龄儿男婴和女婴脐血浆脂联素、血脂各成分水平比较差异均无显著性(P>0.05)。结论血脂联素水平的变化与大于胎龄儿的发生有关,测定脐血脂联素水平有助于判断大于胎龄儿的发展趋势,为早期预防糖尿病、心血管疾病等多种肥胖相关性疾病的发生开拓新的思路。     

Dynamics of formation of primary and secondary lipid peroxidation products upon copper-dependent oxidation of low-density lipoproteins isolated from blood serum of patients with ischemic heart disease

The kinetics of copper-induced oxidation of lipids in serum low-density lipoproteins from healthy subjects and patients with ischemic heart disease and documented coronary atherosclerosis is studied. After a 4-h incubation with 40 μM CuSO₄, the oxidizability of patients' lipoproteins is higher, judging from the contents of diene conjugates and oxidation products reacting with thiobarbituric acid. Intergroup differences in the kinetics of the diene conjugate formation are revealed. Statistical analysis shows that in all studied individuals there is no relationship between the oxidizability of low-density lipoproteins and the cholesterol content in lipoproteins and serum. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 7, pp. 32–36, July, 1996     

Hyaluronan turnover in the rat small intestine

The main metabolic pathway for the interstitial matrix component hyaluronan seems to be via lymph. Present estimates of turnover of intestinal hyaluronan are based on isolated organs and/or experiments in anaesthesia over a few hours. In this study lymph was sampled from the main mesenteric lymphatic for 24 h in awake, restrained rats. The tissue content of hyaluronan averaged 28 /μ g^-1 in the duodenum/jejunum and 124 μ g^-1 in the colon. Based on tissue content and lymphatic output, the turnover rate of hyaluronan in the small intestine was estimated at approximately 50%. In another experimental group anaesthetized rats were fed either phosphate buffer or triolein in buffer via a gastric tube. Lymph flow increased with fluid absorption from the gut and hyaluronan output in lymph was elevated correspondingly. However, no effect of acute fat administration on hyaluronan concentration or lymph flow could be demonstrated.     

The Lipofuscin-Iron Association in Pigmentosis Tubae

Pigmentosis tubae (PT) is a rare condition characterized by the presence of numerous lipofuscin-laden macrophages in the lamina propria of the fallopian tube. Two women, who also had endometriotic ovarian cysts, showed polypoid pigmented tubal mucosae. In addition to lipofuscin, occasional cells showed spotty positivity for iron. Ultrastructural examination of the tubal mucosa showed the lipofuscin-containing bodies, which were similar to lipofuscin-containing lysosomes found in other pigmented conditions. Cytoplasmatic ferritin and hemosiderin in siderosomes were observed in macrophages and endothelial cells of the lamina propria. The present study is the first to demonstrate the presence of iron-containing particles and lipofuscin in the residual bodies of PT. The origin of the excess iron is not clear, but erythrophagocytosis and an abnormal tubal environment could play a role. Iron-promoted lipid peroxidation may alter the lysosomal membranes and contribute to the excessive accumulation of lipofuscin in these cells.     

Plasma insulin and lipid levels in untreated obstructive sleep apnoea and snoring; their comparison with matched controls and response to treatment

SUMMARY  Obstructive sleep apnoea (OSA), and snoring are associated with coronary heart disease. To assess whether OSA or snoring may contribute to this by raising fasting lipid or insulin levels, venous fasting total cholesterol, triglyceride, very-low-density lipoprotein, low-density lipoprotein, high-density lipoprotein, and insulin were measured in 15 untreated OSA patients and 18 snorers. Each of these subjects was individually matched to a control of the same sex, age ± 10%, body index ± 15%, smoking and drinking habits. This produced study groups which did not differ significantly by any of these criteria. Fasting venous blood samples were collected at 06.30 hours following polysomnography, and analysed blind of the subjects respiratory status. The OSA patients were then treated with nasal continuous positive airway pressure. In 10 of these subjects lipid and insulin levels were repeated after more than three months treatment. Lipid and insulin levels were also remeasured in the controls matched to these 10 subjects. The end points were compared with paired t -tests.
There was no difference in any of the end points when the untreated OSA patients and the snorers were compared to their matched controls ( P >0.25 for all comparisons), and none of the indices changed when OSA was corrected with nasal continuous positive airway pressure ( P > 0.25 for all comparisons).
Patients with obstructive sleep apnoea or snoring do not have significant fasting hyperlipidaemia or hyperinsulinaemia when compared to carefully matched controls. These factors are therefore unlikely to be the cause of the excess cardiovascular mortality experienced by this patient group.     

磷脂双层膜稳定性的理论分析

目的：越来越多磷脂双层膜的原子力显微镜扫描力谱显示溶液离子浓度对磷脂双层膜稳定性有很大影响，本文从理论角度研究溶液离子浓度对磷脂双层膜稳定性的影响，同时解释两个基于不同模型模拟结果差别的原因。方法：主要根据磷脂分子极性端带电特性，将极性端看作偶极子，然后基于偶极-偶极相互作用理论以及泊松-玻尔兹曼理论解决以上问题。结论：随着离子浓度的增加，磷脂双层膜趋于更加稳定；基于两个不同模型模拟结果差别的原因是高浓度溶液的强静电屏蔽作用。     

Behavior of 3-year-old children in a prospective randomized trial of reduced saturated fat and cholesterol diet since infancy: The strip baby project

Interventions aimed at decreased exposure of children to known atherosclerosis risk factors may have untoward behavioral side effects. We examined how children’s behavior or parent’s perception of the behavior of the children at 3 years of age was influenced by the intervention in a prospective randomized trial that began in infancy and effectively decreased scrum cholesterol concentration. This Special Turku coronary Risk factor Intervention Project for babies (STRIP) began when the infant was 7 months old. Half of 1.062 children received individualized dietary counseling at 1-to 3-month intervals during the first 2 years of age and then half-yearly; the other half had an unrestricted diet. At 3 years of age a standardized questionnaire of the child’s behavior was sent to 791 families (76% returned the questionnaire). At the onset of the trial the sociodemographic data of the families and scrum lipid values of the intervention and control children were similar. Later, mean serum cholesterol values of the intervention children remained constantly at a level 6% to 10% below the values of the control children. At 3 years of age the parental perceptions of the child’s behavior suggested minimal differences between the intervention and control children. The intervention children were slightly less jealous and more active and creative, but showed slightly more negative signs of behavior (bed-wetting, problems in falling asleep, fears) than the controls. We conclude that long-term, individualized dietary and lifestyle intervention that begins in infancy slightly influences children’s behavior or parent’s recognition of the behavior of the children at the age of 3 years. This work was supported in part by grants from the Varsinais-Suomi Regional Fund of the Finnish Cultural Foundation, the Mannerheim League for Child Welfare, the Academy of Finland, and the Alli Paasikivi Foundation.     

Correlation between the occurrence of 1H-MRS lipid signal, necrosis and lipid droplets during C6 rat glioma development

The aim of this study was to investigate the possible correlation between the 1H MRS mobile lipid signal, necrosis and lipid droplets in C6 rat glioma. First, the occurrence of necrosis and lipid droplets was determined during tumor development, by a histological analysis performed on 34 rats. Neither necrosis nor lipid droplets were observed before 18 days post-implantation. At later stages of development, both necrosis and lipid droplets were apparent, the lipid droplets being mainly located within the necrotic areas. Using a second group of eight rats, a temporal correlation was evidenced between mobile lipid signal detected by in vivo single-voxel one- (136 ms echo time) and two-dimensional J-resolved 1H MR spectroscopy, and the presence of necrosis and lipid droplets on the histological sections obtained from the brains of the same rats. Finally, spatial distribution of the mobile lipid signal was analyzed by chemical-shift imaging performed on a third group of eight animals, at the end of the tumor growth. The spectroscopic image corresponding to the resonance of mobile lipids had its maximum intensity in the center of the tumor where necrotic regions were observed on the histological sections. These necrotic areas contained large amounts of lipid droplets. All these results suggest that mobile lipids detected in vivo by 1H MRS (136 ms echo time) in C6 rat brain glioma arise mainly from lipid droplets located in necrosis.