高脂饮食豚鼠高密度脂蛋白代谢的特点

目的研究豚鼠高脂饮食后高密度脂蛋白代谢的特点,并与大鼠进行比较。方法将豚鼠和大鼠分别随机分为正常组（NC）和高脂组（HF）,正常组均给予普通饲料,高脂组给予高脂饲料诱导10周后,测定血清LDL-C、HDL-C水平,HDL3/HDL2比值和LCAT、CETP的表达;采用real-time RT-PCR方法检测肝脏SR-BI表达的变化。结果与正常组相比,豚鼠高脂组血清HDL-C水平显著升高,高密度脂蛋白亚型HDL3/HDL2的比值升高,血清CETP表达均显著增加,血清LCAT表达下降,肝脏SR-BI mRNA表达水平是正常组的2.27倍。而相同高脂饲料条件下,大鼠的上述指标均无明显变化。结论豚鼠摄入高脂饮食后HDL代谢与大鼠有所不同,主要表现为血清HDL-C升高,肝脏SR-BI受体表达增加,高密度脂蛋白亚型组分发生变化,大颗粒HDL2含量相对减少,小颗粒HDL3堆积,其机制与血清CETP、LCAT的变化密切相关。     

Abiotic Formation of Valine Peptides Under Conditions of High Temperature and High Pressure

We investigated the oligomerization of solid valine and the stabilities of valine and valine peptides under conditions of high temperature (150–200 °C) and high pressure (50–150 MPa). Experiments were performed under non-aqueous condition in order to promote dehydration reaction. After prolonged exposure of monomeric valine to elevated temperatures and pressures, the products were analyzed by liquid chromatography mass spectrometry comparing their retention times and masses. We identified linear peptides that ranged in size from dimer to hexamer, as well as a cyclic dimer. Previous studies that attempted abiotic oligomerization of valine in the absence of a catalyst have never reported valine peptides larger than a dimer. Increased reaction temperature increased the dissociative decomposition of valine and valine peptides to products such as glycine, β-alanine, ammonia, and amines by processes such as deamination, decarboxylation, and cracking. The amount of residual valine and peptide yields was greater at higher pressures at a given temperature, pressure, and reaction time. This suggests that dissociative decomposition of valine and valine peptides is reduced by pressure. Our findings are relevant to the investigation of diagenetic processes in prebiotic marine sediments where similar pressures occur under water-poor conditions. These findings also suggest that amino acids, such as valine, could have been polymerized to peptides in deep prebiotic marine sediments within a few hundred million years.     

High Country Adaptations

Abstract

A general model of high country adaptations by hunters and gatherers is proposed. It is derived from a consi eration of the specific nature of high country resources and the social structure that seems to exploit them most efficiently. The general model is then illustrated by two test cases, one from northwestern Wyoming and one from southwestern Asia. The paper concludes with a comparative perspective. and discusses the problem of why Native Amen cans 1n the central Rockies failed to domesticate wild sheep while hunters and gatherers in southwestern Asia did.     

High resolution scintiautoradiography

An electron microscopic scintiautoradiographic method for studying histological sections is reported. An increase in the silver grain yield is attained by using a scintillator in embedding medium. The amplification effect for 3H-labeling reaches 3-fold and for 14C reaches a 15-fold. No lessening of autoradiographic resolution was observed. On the basis of these preliminary results only qualitative evaluation of data is discussed.     

High resolution electrocardiography

Over the past decade, significant advances were made in the research, diagnosis, and treatment of cardiovascular diseases. Such progress was in every sphere of cardiology that includes non-invasive, minimally invasive, and invasive technologies. Interpretive electrocardiography, cardiac pacemakers, cardiac stents, and angioplasty are some areas where the progress has been significant. Non-invasive methods of diagnosis of cardiac disorders involve digital recording of cardiac signals at the body surface (chest) and subsequent computerized analysis. Such methods and instruments provide a vital first step to the diagnosis of the heart without involving surgical procedures. One such non-invasive field is High Resolution Electrocardiography (HRECG). A high-resolution electrocardiogram detects very low amplitude signals in the ventricles called 'Late Potentials' in patients with abnormal heart conditions. A standard electrocardiogram cannot detect these signals. The presence of late potentials is widely accepted to have prognostic significance in patients after Acute Myocardial Infarction (AMI) High Resolution Electrocardiography enhances the diagnostic capabilities of ECGs. This article describes the principles involved in HRECG and the techniques that are employed to derive such superior diagnostic capabilities. The use of these techniques may lead to more discoveries in the causes of cardiac disorders and improved drug discoveries to combat such conditions.     

Impact of a Combined High Cholesterol Diet and High Glucose Environment on Vasculature

Aims

Vascular complications are the leading cause of mortality and morbidity in patients with diabetes. However, proper animal models of diabetic vasculopathy that recapitulate the accelerated progression of vascular lesions in human are unavailable. In the present study, we developed a zebrafish model of diabetic vascular complications and the methodology for quantifying vascular lesion formation real-time in the living diabetic zebrafish.

Methods and Results

Wild type zebrafish (AB) and transgenic zebrafish lines of fli1:EGFP, lyz:EGFP, gata1:dsRed, double transgenic zebrafish of gata1:dsRed/fli1:EGFP were exposed to high cholesterol diet and 3% glucose (HCD-HG) for 10 days. The zebrafish model with HCD-HG treatment was characterized by significantly increased tissue levels of insulin, glucagon, glucose, total triglyceride and cholesterol. Confocal microscopic analysis further revealed that the diabetic larvae developed clearly thickened endothelial layers, distinct perivascular lipid depositions, substantial accumulations of inflammatory cells in the injured vasculature, and a decreased velocity of blood flow. Moreover, the vascular abnormalities were improved by the treatment of pioglitazone and metformin.

Conclusion

A combination of high cholesterol diet and high glucose exposure induces a rapid onset of vascular complications in zebrafish similar to the early atherosclerotic vascular injuries in mammalian diabetic models, suggesting that zebrafish may be used as a novel animal model for diabetic vasculopathy.