Timing of Initiation of RRT and Modality Selection

There is no shortage of studies and registry data examining outcomes of patients on dialysis and those with a renal transplant. However, recently, there has been a greater focus on the events leading up to the institution of kidney replacement therapy. Associative data suggest that early and consistent predialysis care leads to better outcomes, including greater take-on to home-based therapy, diminished use of tunneled venous hemodialysis catheters, and improved early and even late survival. What transpires during predialysis visits is also important. Simple dissemination of facts to the unprepared patient is unlikely to be effective in moving the patient and family along in the process of the series of choices that have to be made around therapy. A more flexible and circumspect approach is needed, including recognizing when the patient is or is not ready for change. There seems to be no optimal timing of dialysis start that can be applied to the ESRD population as a whole, although the pendulum seems to be swinging back toward symptom-based rather than eGFR-based starts.     

Basic Principles of the Echocardiographic Evaluation of Mitral Regurgitation

Mitral regurgitation (MR) is a common form of valvular heart disease that is associated with significant morbidity and mortality. Treatment decisions are completely dependent on accurate diagnosis of both mechanism and severity of MR, which can be challenging and is often done incorrectly. Transthoracic echocardiography is the most commonly used imaging test for MR; transesophageal echocardiography is often needed to better define morphology and MR severity, and is essential for guiding transcatheter therapies for MR. Multidetector computed tomography has become the standard to assess whether transcatheter valve replacement is an option because of its ability to assess valve sizing, access, and potential left ventricular outflow tract obstruction. Finally, cine cardiac magnetic resonance has been recommended by recent guidelines to quantify MR severity when the distinction between moderate and severe MR is indeterminate by echocardiography. This paper focuses on the main questions to be answered by imaging techniques and illustrates some common tips, tricks, and pitfalls in the assessment of MR.     

主动脉瘤动物模型研究进展

主动脉瘤是一种多因素影响、具有潜在破裂风险的主动脉病理扩张性疾病。根据发病位置主动脉瘤可分为胸主动脉瘤和腹主动脉瘤。胸主动脉瘤的发生与年龄和性别相关性不大,而与遗传因素高度相关;腹主动脉瘤的发生与年龄、性别、动脉粥样硬化等相关,但与遗传关联性较弱。主动脉瘤一般具有发病隐匿和破裂致死等特征,是严重威胁人类生命健康的慢性疾病,但其发病机制尚不完全清楚。主动脉瘤动物模型是研究人主动脉瘤的重要工具,对阐释主动脉瘤的病理生理学机制、研发和评价主动脉瘤的治疗药物都具有重要意义。当前关于腹主动脉瘤的动物模型有很多,也比较成熟,但是关于胸主动脉瘤的动物模型较少。实际上,多种方法诱导的腹主动脉瘤模型中,也会出现胸主动脉瘤,只不过发病率不同,胸主动脉瘤的发病率较低。本文将主动脉瘤动物模型归纳为非夹层主动脉瘤动物模型和夹层主动脉瘤动物模型,并简要综述这两类模型的构建方法及表型,为人类动脉瘤的防治研究提供参考。     

Diagnosis and management of complications of prosthetic heart valves

Complications after heart valve replacement remain a substantial source of morbidity and mortality despite continuing advances in surgical care and prosthetic design. Infectious endocarditis occurs in about 4 percent of patients and may appear early (within 60 days) or late after operation. Endocarditis of early onset is commonly due to staphylococcal, fungal or gram-negative organisms and is fatal in 70 percent or more of cases. Infection of late onset is more often of streptococcal origin and the mortality rate is lower, about 35 percent. With either type, prompt recognition, vigorous and appropriate antimicrobial therapy and early consideration of surgical intervention are crucial.

The postperfusion and postpericardiotomy syndromes are relatively common and relatively benign syndromes associated with postoperative fever. Their recognition is important to prevent confusion with endocarditis or sepsis and thus to reassure the patient and physician. Treatment is primarily symptomatic. Intravascular hemolysis occurs with most prosthetic heart valves but is more common with certain prostheses and with paraprosthetic valve regurgitation, with significant hemolytic anemia in 5 to 15 percent. Oral iron replacement therapy is effective in the majority of patients, but occasionally blood transfusion or reoperation for leak around the prosthesis is necessary. Prosthesis dysfunction due to thrombus may be recognized clinically by recurrence of heart failure, syncope, cardiomegaly and altered prosthetic valve sounds or new murmurs. Hemodynamic studies verify the diagnosis, and prompt reoperation is indicated for this potentially lethal problem. Systemic embolization has decreased markedly with the introduction of cloth-covered prostheses and is frequently related to erratic or ineffective anticoagulant therapy. We continue to recommend anticoagulant therapy for all patients with prosthetic heart valves unless there is a major contraindication.     

卫生假说的免疫学机制在哮喘防治中的研究进展

哮喘的特征是慢性气道炎症和气道高反应性。目前对哮喘治疗的认识是“可以控制,但不能治愈”。近年来,哮喘发病的“卫生假说”提出早期微生物的暴露可能对哮喘的发病起保护作用。传统的解释是微生物负荷增加可诱导免疫反应向Th1偏移。由于哮喘是由免疫耐受缺陷导致的疾病,因此诱导抗原特异性T细胞耐受可能是此假说的另一种解释,并有望因此为防治哮喘提供新的思路。     

细菌性感染实验室诊断的研究进展

为适应现代感染学的需要，细菌性感染实验室诊断的研究方向应趋于快速、简便、灵敏及经济。其中显微镜检查是常用的简便方法；分离培养和鉴定是基本的必不可少的传统方法，鉴定技术发展迅速；分子生物学技术是发展最快、最具潜力的方法，当样本中病原菌含量太低时，可用PCR方法在体外进行DNA扩增，不需进行分离培养，核酸杂交技术广泛用于细菌的鉴定，在检测难分离培养或不能培养的细菌、生长周期长的细菌及血清学不易测出的细菌及细菌毒素时显示其优越性，生物芯片技术实现对众多病菌进行同步检测，也可用于检测病原体的耐药性。     

Pharmacokinetics and Mode of Action of Tienilic Acid

A review of the absorption, distribution, metabolism and excretion of ticrynafen (tienilic acid) in 8 animal species, including man, is presented. Although some species effects are apparent, ticrynafen absorption is essentially complete following oral administration. The compound is extensively bound to plasma proteins, primarily albumin. Consequently, tissue concentrations are generally lower than plasma concentrations. Plasma and whole body clearance of ticrynafen is rapid due both to metabolism and to extensive renal excretion of the compound and its metabolites. Male/female differences in renal excretion occur, with a subsequent effect on ticrynafen metabolism.

Ticrynafen is an inhibitor of reabsorption of sodium and uric acid by the kidney. This inhibitory effect, within the renal tubular lumen, accounts for its diuretic and uricosuric activity and could account for its antihypertensive activity, although a direct effect has also been claimed.

Ticrynafen is also a classical example of a competitive inhibitor of organic acid transport in the kidney and other organs. Much of the drug-drug interaction involving ticrynafen is understandable due to its effect on transport. However, potentiation of anticoagulant activity appears to involve some direct effects upon warfarin metabolism although ticrynafen, in general, is not an enzyme inducer or inhibitor.

Toxicity of ticrynafen is low in all animal species.     

Influence of environmental statistics on inhibition of saccadic return

Initiating an eye movement is slowed if the saccade is directed to a location that has been fixated in the recent past. We show that this inhibitory effect is modulated by the temporal statistics of the environment: If a return location is likely to become behaviorally relevant, inhibition of return is absent. By fitting an accumulator model of saccadic decision-making, we show that the inhibitory effect and the sensitivity to local statistics can be dissociated in their effects on the rate of accumulation of evidence, and the threshold controlling the amount of evidence needed to generate a saccade.     

Effect of Sc on the Hot Cracking Properties of 7xxx Aluminum Alloy and the Microstructure of Squeeze Castings

In this paper, the effect of adding the refiner Sc to the high Zn/Mg ratio 7xxx series aluminum alloy melt on the hot tearing performance, microstructure, and mechanical properties of the alloy is studied. The hot tearing performance test (CRC) method is used to evaluate the hot tearing performance of the alloy. The squeeze casting process was used to form solid cylindrical parts to analyze the structure and properties of the alloy. This study shows that the hot cracking sensitivity of the alloy after the addition of the refiner Sc is significantly reduced. The ingot grain size is significantly reduced, and the average grain size is reduced from about 86 μm to about 53 μm. While the mechanical properties are significantly improved, and the tensile strength reduced from 552 MPa is increased to 571 MPa, and the elongation rate is increased from 11% to 14%.     

Shaping the Microstructure of High-Aluminum Cast Iron in Terms of the Phenomenon of Spontaneous Decomposition Generated by the Presence of Aluminum Carbide

A suitable aluminum additive in cast iron makes it resistant to heat in a variety of environments and increases the abrasion resistance of the cast iron. It should be noted that high-aluminum cast iron has the potential to become an important eco-material. The basic elements from which it is made—iron, aluminum and a small amount of carbon—are inexpensive components. This material can be made from contaminated aluminum scrap, which is increasingly found in metallurgical scrap. The idea is to produce iron castings with the highest possible proportion of aluminum. Such castings are heat-resistant and have good abrasive properties. The only problem to be solved is to prevent the activation of the phenomenon of spontaneous decomposition. This phenomenon is related to the Al₄C₃ hygroscopic aluminum carbide present in the structure of cast iron. Previous attempts to determine the causes of spontaneous disintegration by various researchers do not describe them comprehensively. In this article, the mechanism of the spontaneous disintegration of high-aluminum cast iron castings is defined. The main factor is the large relative geometric dimensions of Al₄C₃ carbide. In addition, methods for counteracting the phenomenon of spontaneous decay are developed, which is the main goal of the research. It is found that a reduction in the size of the Al₄C₃ carbide or its removal lead to the disappearance of the self-disintegration effect of high-aluminum cast iron. For this purpose, an increased cooling rate of the casting is used, as well as the addition of elements (Ti, B and Bi) to cast iron, supported in some cases by heat treatment. The tests are conducted on the cast iron with the addition of 34–36% mass aluminum. The molten metal is superheated to 1540 °C and then the cast iron samples are cast at 1420 °C. A molding sand with bentonite is used to produce casting molds.     

Current status of diagnosis and treatment of hepatic echinococcosis

Echinococcus granulosus(E.granulosus) and Echinococcus multilocularis(E.multilocularis) infections are the most common parasitic diseases that affect the liver.The disease course is typically slow and the patients tend to remain asymptomatic for many years.Often the diagnosis is incidental.Right upper quadrant abdominal pain,hepatitis,cholangitis,and anaphylaxis due to dissemination of the cyst are the main presenting symptoms.Ultrasonography is important in diagnosis.The World Health Organization classification,based on ultrasonographic findings,is used for staging of the disease and treatment selection.In addition to the imaging methods,immunological investigations are used to support the diagnosis.The available treatment options for E.granulosus infection include open surgery,percutaneous interventions,and pharmacotherapy.Aggressive surgery is the first-choice treatment for E.multilocularis infection,while pharmacotherapy is used as an adjunct to surgery.Due to a paucity of clinical studies,empirical evidence on the treatment of E.granulosus and E.multilocularis infections is largely lacking;there are no prominent and widely accepted clinical algorithms yet.In this article,we review the diagnosis and treatment of E.granulosus and E.multilocularis infections in the light of recent evidence.     

Determination of Suitable Imaging Techniques for the Investigation of the Bonding Zones of Asphalt Layers

The material behavior of asphalt depends on its composition of aggregate, bitumen, and air voids. Asphalt pavements consist of multiple layers, making the interaction of the materials at the layer boundary important so that any stresses that occur can be relieved. The material behavior at the layer boundary is not yet understood in detail, as further methods of analysis are lacking in addition to mechanical methods. For this reason, the layer boundary of asphalt structures was analyzed using imaging methods. The aim of this research was to find an imaging method that allows a detailed analysis of the bonding zone of asphalt layers. Two different imaging techniques were used for this purpose. One is a 2-D imaging technique (asphalt petrology) and the other is a 3-D imaging technique (high-resolution computed tomography). Image analysis is a widely used technique in materials science that allows to analyze the material behavior and their composition. In this research, attention was paid to the analysis of the position of the bitumen emulsion, because the contained bitumen is supposed to bond the layers together. It was found that the application of 2-D imaging (asphalt petrology) lacked the precision for a detailed analysis of the individual materials at the layer boundary. With high-resolution computed tomography, a detailed view is possible to visualize the individual materials at the layer boundary in 3D. However, it is difficult to differentiate the materials because there are no gradations in the gray values due to the identical densities. However, it is possible to differentiate between the bitumen from the asphalt and from the emulsion if a high-density tracer is added to the bitumen emulsion for the CT studies. The results of the investigations are presented in this article.     

Semantics of insulin

The lack of a stringent terminology and a well-defined vocabulary for insulin and related subjects has been a deterrent to solving many of the problems encountered when using insulin in pumps. The same word is sometimes used to describe a number of different phenomena or the same phenomenon is referred to by different words. Thus the word 'insulin', meaning the substance, the protein hormone, is commonly used as a synonym for an 'insulin formulation' for the treatment of diabetes. The 'insulin dimer' can be the covalent or the non-covalent dimer, two very different substances. 'Isoelectric precipitation' is often mistaken for 'fibrillation' and both are referred to as 'aggregation' or 'polymerization'. The word 'crystal' is being used as a synonym for 'particle', and determination of 'the content of insulin' by HPLC is sometimes called a 'bioassay'. The nature and consequences of these pitfalls are discussed, and advice is given on how to avoid them.     

Prediction of Surface Roughness of Abrasive Belt Grinding of Superalloy Material Based on RLSOM-RBF

It is difficult to accurately predict the surface roughness of belt grinding with superalloy materials due to the uneven material distribution and complex material processing. In this paper, a radial basis neural network is proposed to predict surface roughness. Firstly, the grinding system of the superalloy belt is introduced. The effects of the material removal process and grinding parameters on the surface roughness in belt grinding were analyzed. Secondly, an RBF neural network is trained by reinforcement learning of a self-organizing mapping method. Finally, the prediction accuracy and simulation results of the proposed method and the traditional prediction method are analyzed using the ten-fold cross method. The results show that the relative error of the improved RLSOM-RBF neural network prediction model is 1.72%, and the R-value of the RLSOM-RBF fitting result is 0.996.     

The role of cryosurgery in the management of cardiac arrhythmias

In the late 1970s, cryoablation of the AV node, accessory pathways, and ventricular tachycardia was first demonstrated and the technique was thought likely to assume an increasing importance in the surgical management of cardiac arrhythmias. However, more than 10 years later, cryotherapy is relatively sparingly used in these situations, and is at best an adjunctive means of therapy. The principal reason for this may lie in what was thought to be its major advantage: the fact that it is a highly selective, precise means of ablating myocardial tissue. Whereas electrophysiological mapping of tachycardia is able to identify apparently localized areas of arrhythmia substrate, relatively wide surgical destruction of myocardial tissue is frequently required to ensure successful tachycardia abolition: discrete, precise means of ablation are at a disadvantage. The future role for cryosurgery would seem to lie in those areas of arrhythmia management where selective ablation of substrate is essential. The ability of cryosurgery to modify (rather than simply ablate) AV nodal physiology in patients with AV nodal re-entrant tachycardia is such that it is likely to rival the recently reported catheter techniques for modification of the AV node.     

Clinical relevance of frozen diagnosis of ductal margins in surgery of bile duct cancer

It is anticipated that free surgical margin is crucial for curative resection of bile duct cancer. However, the clinical relevance of the ductal margin is somewhat controversial. A role of frozen section diagnosis used for evaluation of the ductal margin during surgery is also ambiguous. We reviewed the current knowledge about frozen section diagnosis and the clinical relevance of the margin status in surgery of the bile duct cancer. Frozen section diagnosis of the ductal margin of bile duct cancer is necessary to ensure free margins; however, it is quite challenging even for experienced pathologists because the bile duct involved with bile duct cancer is often inflamed severely due to obstruction and/or insertion of a draining tube, which induces epithelial regeneration with atypia. Also accessory ducts/peribiliary glands and their conduits in ductal wall can mimic invasive ductal components, which requires careful examination to evaluate regenerative change, carcinoma in situ, or invasive carcinoma. Published studies assessing an association between the ductal margin state and prognosis in relatively large cohorts of patients undergoing surgery for bile duct cancer indicate that the ductal margin status is an independent prognostic factor; and the ductal margin with carcinoma in situ is comparable to free margin; however, the margin with invasive carcinoma is significantly adverse for patients' prognoses.     

甘露醇对黏液纤毛清除功能受损疾病的作用

甘露醇干粉吸入剂是一种高渗性物质,进入气道后,形成渗透压阶梯,促进水分向气道腔扩散.这一过程不仅增加纤毛周围液体层厚度,而且水化黏液,使黏液的流变学特性发生改变,从而易化黏液纤毛清除.应用于黏液高分泌伴黏液纤毛清除功能受损的疾病,甘露醇能够改善其气道环境,减少黏液沉积及黏液栓形成,减轻症状,改善肺功能,减少细菌定植及慢性感染导致疾病加重的机会,最终提高患者生活质量.因此,它可能成为一种具有潜力的治疗黏液高分泌疾病的药物.临床试验已经证明其短期效果较佳,但长期效果尚待进一步的临床试验验证.     

Metabolic studies on the possible mode of action of isoniazid tumorigenicity

Summary Data on tumorigenicity and mutagenicity of INH show that INH is tumorigenic in mice but not in rats. The metabolic studies on the two species denote that rats are rapid inactivators whereas mice are slow inactivators of INH. Rats are also resistant to the immediate inhibitory effect of INH on DNA biosynthesis. Using Ames test it was observed that INH is mutagenic to salmonella typhimurium strains TA 100 and 1535 and this effect is abolished in presence of 59 mixture. In vivo and in vitro studies on INH interaction with macromolecules reveal that there is a greater interaction with RNA than with DNA and the site of interaction is the cytidine and deoxycytidine, respectively. A preliminary study is undertaken to see if healed TB cases have a higher risk for cancer. It is found that cancer incidence in this group is higher as compared to noncancer patients.     

A Re-Examination of the Alleged Monocytic Features of Hairy-Cell Leukaemia

A number of the ‘monocytic’ features of the hairy cells (HCs) of hairy-cell leukaemia (HCL) are studied in detail and discussed in relation to the now established B-cell nature of the disease. By means of a rosette assay employing erythrocytes coated with IgG (EAG), a receptor for the Fc of IgG is shown to be strongly expressed on all HCs, whether in suspension or in monolayers. This receptor is shed and re-expressed over a period of some 6 h. In EAG rosette formation the indicator erythrocytes are deformed and the receptor is not blocked by an antiserum to the la-like antigen. By ultrastructural acid-phosphatase cytochemistry, it is established that HCs phago-cytose latex particles, but do not phagocytose a variety of other particles to a significant extent. These, and other features, are discussed in relation to the literature and it is shown that all are compatible with the current view that HCL is a form of B-cell lymphoproliferation.     

骨髓基质干细胞自体移植治疗心肌梗死的研究进展

骨髓基质干细胞(MSC)具有良好的分化潜能,能分化为心肌细胞和血管内皮细胞,从而再生心肌和血管,重塑心肌结构,改善心肌收缩功能和室壁顺应性,促进血管再生,建立有效冠脉侧枝循环,提高心脏整体功能,既改善了血供又解决心肌细胞数量减少这一心力衰竭的根本原因;而自体移植不受来源限制,取材方便、创伤小,更新率低而代谢活力高,由其分化来的心肌细胞能与周围受体肌肉细胞进行有效的电机械偶合,容易通过转基因技术获得目标基因并在体内外长期表达,也不存在免疫排斥和基因突变等安全性问题,因此作为心肌梗死(MI)疾病治疗的新途径有着广阔的前景.现就近年来国内外MSC自体移植在治疗MI方面的研究进展作一综述.