异体脱钙骨基质复合bBMP修复兔桡骨骨缺损

目的：探讨异体脱钙骨基质复合BMP修复节段性骨缺损的能力。方法：64只新西兰大白兔采用桡骨15mm节段性骨缺损模型，随机分为4组，A组植入异体脱钙骨基质(Demineralized Bone Matrix,DBM)与牛骨形态发生蛋白(Bovine Bone Morphogentic Protein,bBMP)复合材料，B组植入异体DBIM，C组植入异体骨粒，D组为空白对照组。术后4、8、12、16w，进行放射学检查、病理组织学检查和计算机图像分析新生骨面积。结果：异体DBM与bBMP复合材料组骨生成、新骨面积和骨连接情况明显优于异体DBM组、异体骨粒组和空白对照组。结论：异体DBM复合BMP材料通过骨诱导和骨传导两种方式修复骨缺损，是一种较为理想、具有高效成骨活性的植骨材料。     

增生性玻璃体视网膜病变基质金属蛋白酶的定量研究

目的:研究增生性玻璃体视网膜病变(proliferative vitreoretinopathy,PVR)玻璃体中基质金属蛋白酶(matrix metalloproteinases,MMPs)的表达,探讨MMPs在PVR病理过程中的作用。方法:PVR患者采用标准三切口巩膜扁平部玻璃体切割术(pars plana vitrectomy,PPV),取未稀释的玻璃体21只眼,PPV术后复发的玻璃体腔液20只眼,意外死亡的正常人玻璃体10只眼,采用明胶酶谱分析法定量分析MMP-2和MMP-9活性水平。结果:PVR玻璃体有MMP-2活性水平增高,与正常玻璃体比较差异有显著性意义(P<0.05)。21眼PVR玻璃体中13只眼有MMP-9活性水平增高,平均(171.52±13.17)扫描单位。20眼PPV术后PVR复发的玻璃体腔液19只眼有MMP-9活性水平增高,平均(156.01±37.21)扫描单位。正常人玻璃体无MMP-9的表达。结论:PVR玻璃体有MMP-2和MMP-9活性水平增高,MMP-9活性水平增高可能与术后PVR复发有关。眼科学报2003;19:130-132。     

MR imaging of viscoelastic properties

Mechanical waves in magnetic resonance imaging, which have been suggested for possible clinical applications, were analyzed with regard to imaging of the viscoelastic properties of large objects. The method is based on the Larmor frequency modulation caused by the application of mechanical waves. Possible clinical applications include all diseases that result in a change in the mechanical properties of biologic tissues (eg, atherosclerosis).     

Structure and Behavior in Hydrophilic Matrix Sustained Release Dosage Forms: 4. Studies of Water Mobility and Diffusion Coefficients in the Gel Layer of HPMC Tablets Using NMR Imaging

Purpose. The purpose of this study was to characterise the water mobility in the gel layer of hydrating HPMC tablets. Water mobility in the gel layer of different HPMCs was studied. Methods. NMR imaging, a non-invasive technique, has been used to measure the spatial distribution of self-diffusion coefficient (SDC) and T₂ relaxation times across the gel layer. Results. It has been shown that there is a water mobility gradient across the gel layer of HPMC tablets. Although SDC and T₂ relaxation times in the outer parts of the gel layer approached that of free water, in the inner parts they decreased progressively. Water mobility and SDC in the gel layer of different HPMCs appeared to vary with degree of substitution of the polymer and the lowest values were obtained across the gel layer of K4M tablets. Conclusions. Water mobility varies across the gel layer of hydrating HPMC tablets and it is dependent on the degree of substitution of the polymer.     

The incidence, timing, and predisposing factors of germinal matrix and intraventricular hemorrhage (GMH/IVH) in preterm neonates

Background Germinal matrix and intraventricular hemorrhage (GMH/IVH) is a known complication occurring in the first week of life in preterm neonates. However, the precise time of its occurrence and the ideal time to perform diagnostic imaging studies remain controversial. The purpose of this paper is to address these two issues in our patient population to allocate our resources to those at highest risk.Materials and methods This study included 282 premature newborns (under 37 weeks of gestation) that were admitted to our neonate ICU in a year’s time and screened for GMH/IVH. They were grouped in four categories according to their weight at birth, and according to their gestational age. All patients had a daily cranial ultrasound during the first week. It was then repeated once in the second week and once in the third.Results We found that the incidence of GMH/IVH among preterm neonates was 44.68%. It was inversely related to the weight and the age of the newborn. The onset of bleeding coordinated with the occurrence of hypoxia and respiratory distress requiring mechanical ventilation. The majorities occurred in the first 7 days of life; they were mostly grade I and II according to the Papule classification and silent for the most part. Complications were present in 41% of the survivors.     

Platelet additive solutions: A future perspective

Platelet additive solutions (PASs) were first developed in the 1980s, and continued to be improved over the following years. The use of PASs as replacement for plasma has a number of benefits, both for the quality of the platelet concentrates and for the patients. However, some PASs have been associated with a lower platelet yield in the PCs, a shorter storage time, and a lower increment in the patient when compared to PCs in plasma. A number of reformulations of the PASs have taken place to counteract these disadvantages. Most PASs use acetate as nutrient for the platelets, which has the benefit of generating bicarbonate when oxidized by the platelets, thus supplying its own buffering capacity. Alternatively, glucose is used, but may cause deterioration of pH in the stored PCs due to the formation of lactic acid. Addition of other buffering substances, such as phosphate, can be added to ensure maintenance of neutral pH. An important finding was the inhibiting effect of potassium and magnesium on platelet activation. The initially developed PASs lacked these two ingredients and showed reduced storage times of the PCs in PAS when compared to those stored in plasma. However, when these constituents are included in the PAS, storage time is similar and even exceeds those seen for PCs in plasma. Considerable research is done in further formulating the optimal PAS. Bicarbonate is being considered as buffer for these PASs. Also, L-carnitine appears to have a favorable effect on stored platelets, including a reduction of platelet metabolism, and inhibition of apoptosis. Another area of optimization is lowering of plasma content needed for maintaining platelet quality. Where current PASs still need at least 30% residual plasma, there is a trend towards lowering the plasma content to less than 5% with the newer PASs. Preservation of purinergic platelet receptor functionality by ADP-degrading activities in plasma appears to play an important role in this respect. Development of PASs are usually based on in vitro studies alone. It is important to realize that only clinical studies can give definitive answers about the quality of platelets stored in PASs. Sofar, only limited clinical evaluations have been published that either studied the effectiveness of platelets in initially-developed PASs, or were specifically done in combination with pathogen reduction technologies. Thus, PASs seem to be an excellent replacement for (part of) the plasma when producing PCs, and allow extended storage with maintenance of quality, but more clinical studies are needed to substantiate in vitro results.     

Measurement of contact impedance of electrodes used for deep brain stimulation

High frequency electrical stimulation by means of electrodes implanted into the brain has become an accepted technique for treatment of Parkinson's disease. The electrical field distribution normally inserted into the sub thalamic nucleus minimise abnormal brain activity. Square wave pulses of 1–3.6 V with duration of 60–90 μs at a frequency range of 130–185 pps are generally used. Every electrode unit consists of four cylindrical electrodes positioned in a row and can be switched on independently. This paper determines the contact impedance of the electrodes for different frequencies and proposes improvement to reduce the contact impedance between the electrodes and the brain. Measurements were performed by placing the electrodes in a tank filled with saline. Different frequencies were applied on two electrodes via a resistor. The current was measured through the resistor and the voltage was registered between one of the electrodes and a third non current carrying electrode. The obtained values were used to calculate the contact impedance. The result shows large contact impedance for the used frequency compared to the impedance of the treated tissue, which means that variation in contact impedance can result in variation in the electrical field applied to the tissue.     

赖型钩端螺旋体重组DNApCX7的特异性鉴定和限制性内切酶谱分析

本实验将赖型钩端螺旋体（简称钩体）ＤＮＡ基因库的克隆ｐＣＸ７制备成￣（３２）Ｐ－重组ＤＮＡ探针，对８个不同血清群的１７株问号状钩体、双曲钩体ＰａｔｏｃⅠ株以及细螺旋体３０５５株ＤＮＡ进行打点杂交；同时用１５种ＤＮＡ片断进行限制性内切酶谱分析。结果表明，该重组ＤＮＡ具有问号状钩体种（Ｓｐｅｃｉｅｓ）特异性，但与不同问号状钩体之间的同源性程度有差别；限制性内切酶谱分析发现ｐＣＸ７重组ＤＮＡ片段长约１．７ｋｂ，具有１个Ｂｇ１Ⅱ识别位点和３个ＢｓｔＢ１识别位点。     

Serum markers for fibrosis and plasma transforming growth factor-β1 in patients with hepatocellular carcinoma in comparison with patients with liver cirrhosis

In order to elucidate collagen metabolism in hepatocellular carcinoma (HCC) tissue, we compared levels of different potential markers of collagen metabolism and plasma transforming growth factor-β₁ in patients with HCC and in patients with liver cirrhosis. Serum levels of prolyl hydroxylase and the tissue inhibitor of metalloproteinase-1 in patients with HCC were significantly higher than those in patients with liver cirrhosis and increased with the size of the HCC tumour, whereas the serum levels of procollagen type III propeptide and type IV collagen 7S domain were similar in the two groups. In HCC, the increased plasma transforming growth factor-β₁ levels were closely correlated with serum levels of prolyl hydroxylase and the tissue inhibitor of metalloproteinase-1. These findings suggest that, in HCC tissue, the intracellular biosynthesis of collagen is enhanced, whereas the secretion of procollagen is disturbed and the degradation of collagen is suppressed by the excess production of the tissue inhibitor of metalloproteinase-1. The results also suggest that plasma transforming growth factor-β₁ plays an important role in the altered metabolism of collagen in HCC.     

Glycosaminoglycan Supplementation Promotes Nerve Regeneration and Muscle Reinnervation

This study shows that treatment of rats with exogenous glycosaminoglycans stimulates peripheral nerve regeneration, increases the abundance of mRNAs for myelin proteins and promotes muscle reinnervation. After the sciatic nerve had been crushed the number of regenerating axons in the distal stump was markedly and highly significantly increased by glycosaminoglycan treatment throughout the experimental period. The increased number of axons was correlated with increased axon and fibre (axon + myelin) diameter. The abundance of mRNAs for P_o protein and myelin basic protein of regenerating nerves was also affected by treatment with glycosaminoglycans. The increase in mRNA was also observed in the contralateral unlesioned nerve. Such a phenomenon did not occur in saline-treated rats. Glycosaminoglycan treatment markedly increased the number of muscle fibres reinnervated and accelerated the restoration of muscle twitch tension elicited by nerve stimulation. The effect was particularly evident during the early stages (16 and 21 days after nerve crush) of muscle reinnervation.