胃癌癌前病变癌变机制及其逆转的研究进展

胃癌癌前病变与胃癌的发生关系,日益受到重视,近几年来特别强调幽门螺杆菌为引起慢性萎缩性胃炎与胃癌的重要危险因子.因此,许多学者进一步深入研究幽门螺杆菌感染对发生胃癌的危险性,胃癌癌前病变发生癌变的机制以及如何使其逆转,是预防和降低胃癌发病的重要课题.     

MR vascular imaging with a fast gradient refocusing pulse sequence and reformatted images from transaxial sections

The authors present a method for obtaining magnetic resonance (MR) images of intra- and extracranial vessels from thin contiguous transaxial sections. A section-selective gradient refocusing pulse sequence with a short repetition time caused flow-related enhancement from spins that flowed perpendicular to the transaxial sections. The signal was further enhanced by means of flow compensation gradients to rephase any phase shifts resulting from moving spins in the presence of the imaging gradients. Coronal and sagittal sections, reformatted from multiple transaxial sections, are shown to have excellent vessel contrast without the use of contrast material. These images were obtained in 12 minutes of acquisition time from as many as 60 sections of 3-mm thickness. Such a technique shows significant promise for MR angiography.     

瘦素有望成为诊治肿瘤的一个关键点

对瘦素与肿瘤的最新研究进展进行综述，并阐明瘦素参与调节肿瘤发生、发展的可能机制，它可能有望成为早期诊治肿瘤的一个关键点。     

Body fat topography in Indian and Tibetan males of low and normal body mass index.

Body fat topography was determined using anthropometric techniques in young, healthy, Indian and Tibetan adults. Indian subjects had significantly higher fat contents with greater abdominal obesity when compared with Tibetans matched for body mass index (BMI). This differential fat distribution may contribute, in part, to the greater cardiovascular risk of Indians. Using a cross sectional model, the data was also analysed to assess the probable changes in body fat topography with weight gain. This model suggests a preferential gain in abdominal subcutaneous fat as compared to other sites. This data may have implications while evaluating disease risks with weight gain.     

Use of coupling agents to enhance the interfacial interactions in starch-EVOH/hydroxylapatite composites.

Different zirconate, titanate and silane coupling agents were selected in an effort to improve the mechanical properties of starch and ethylene-vinyl alcohol copolymer (EVOH) hydroxylapatite (HA) composites, through the enhancement of the filler particles-polymer matrix interactions and the promotion of the interfacial adhesion between these two phases. The mechanical performance was assessed by tensile tests and discussed on the basis of the respective interfacial morphology (evaluated by scanning electron microscopy). The main relevant parameters were found to be the surface properties and reactivity of the filler (non-sintered HA) and the chemical nature (pH and type of metallic centre) of the added coupling agent. Significant improvements in the stiffness were achieved (about 30% increase in the modulus) when using the acidic zirconate coupling agents. The acidic zirconate combined the capability of crosslinking the polymer matrix with the establishment of donor-acceptor interactions and hydrogen bonding between it and the ceramic particles, leading to very good interfacial adhesion. The optimization of these coupling processes associated with the introduction of higher amounts of filler, may be an effective way to produce composites with mechanical properties analogous to those of the human cortical bone.     

Drug therapy for chronic heart failure due to left ventricular systolic dysfunction: a scientific review. I. Introduction

Heart failure is a complex syndrome resulting from cardiac changes, structural or functional, that cause pump failure and consequently diminished cardiac output. Drug therapy improves patients' prognosis and, based on good-quality evidence, is safe and cost-effective. There are several drug classes that can be used in left ventricular dysfunction, so it may be useful to discuss their stratification and prioritization for clinical practice. This is the first of a series of papers that will present and discuss the most valid, important and applicable evidence on drug therapy in chronic heart failure due to left ventricular systolic dysfunction. We will not discuss acute heart failure (or decompensation of chronic heart failure) or non-pharmacologic treatments (implantable cardioverter-defibrillators, cardiac resynchronization therapy, heart transplantation, anti-platelet therapy, etc.).