Movimiento de alumnos ayudantes: experiencia de una institución cubana

The teaching-support student movement arose out of the necessity to cover the lack of teachers caused by the massive exodus of professionals at the beginning of the Cuban Revolution. Five decades later it is still alive and continuously perfects and adjusts itself according to the dynamic social requirements of the country. This article intends to describe the experience acquired at the University Hospital “Arnaldo Milián Castro” based on the work of teaching-support students in the period from 2011 to 2016, emphasising its achievements and challenges in the fulfilment of its main objectives in Cuban higher medical education such as: to support the development of the instructional and educational process, to address the professional orientation towards specialities deficient in professionals and to quickly acquire skills for teaching, research, and those related to specialities.     

DNA Polymorphism Studies. Approaches to Elucidating Multifactorial Ischaemic Heart Disease: the Apo B Gene as an Example

It is well established that elevated plasma levels of low-density lipoprotein (LDL) particles are a risk factor for ischaemic heart disease with the distribution in LDL levels seen in the general population being the result of interaction between environmental factors, such as dietary fat intake, and genetic variation that is present in different individuals. One of the candidate genes where such variation is likely to occur, is the gene coding for apolipoprotein B (apo B). Many studies have reported an association between a common polymorphism of the apo B gene, detected using the restriction enzyme Xbal, and differences in plasma lipid levels, explaining 3-5% of the variance in LDL-cholesterol levels in samples representative of the healthy population. It has been proposed that the mechanism of this association is due to functional amino acid changes within the apo B protein, that affect LDL catabolism by altering binding affinity to the LDL-receptor. Several amino acid substitutions in the apo B gene have now been characterized, and these form the basis of the different epitopes that create the Ag marker system. Previous studies have reported that the Ag(x) epitope is associated with lower plasma lipid levels, and until recently the molecular basis for this association has been unclear. We have determined that the Ag(x) epitope is associated with both a Pro-Leu₂₇₁₂, and Asn-Ser₄₃₁₁ substitution, with the Leu-Ser allele being associated with significantly lower levels of plasma lipids in a sample of healthy individuals from Sweden. The association between these two amino acids is present in all ethnic groups so far studied, and appears to have been maintained throughout the recent evolutionary history of the human species. Since this amino acid polymorphism explains only part of the differences in plasma lipid levels detected using the Xbal polymorphism, this suggests that there are other functionally important sequence changes that remain to be detected, which will be associated with lipid-raising effects. The identification of these functional changes, and the mechanism by which they act will help in our understanding of the role of gene-environment interaction in determining plasma lipid levels in healthy individuals and in patients.     

Bowel Ultrasound in Crohn Disease: Current Role and Future Applications

Background: The majority of hemochromatosis patients are homozygous for the HFE-C282Y mutation. However, less than half of C282Y homozygous subjects identified by population screening studies actually develop the disease. The cytokine TNF- &;#33 is implicated in the regulation of iron metabolism at different levels. Our aim was to study the role of TNF- &;#33 and its promoter polymorphisms in the phenotypic expression of hemochromatosis in individuals with and without the C282Y mutation. Methods: We studied 4 groups of 10 subjects each: ( 1 ) C282Y homozygotes without clinical hemochromatosis; ( 2 ) C282Y homozygotes with hemochromatosis; ( 3 ) secondary hemochromatosis (without C282Y mutation); and ( 4 ) controls. Groups were age-matched and sex-matched. Peripheral blood mononuclear cells (PBMC) were stimulated with lipopolysaccharide (LPS) and the release of TNF- &;#33 was measured. Additionally, the G/A polymorphisms at position -238 and -308 of the TNF- &;#33 gene were determined by PCR and RFLP analysis in 178 hemochromatosis patients and 41 controls. Results: TNF- &;#33 production from PBMC at 8 and 24 &;#114 h after increasing concentrations of LPS stimulation were similar in the four groups. The prevalence of TNF- &;#33 polymorphisms was similar in patients and controls. The prevalences of cirrhosis, siderosis, median s-ferritin and median ALT values were similar in patients with and without the TNF- &;#33 polymorphisms. Conclusions: Neither TNF- &;#33 released from PBMC nor the presence of TNF- &;#33 polymorphisms seem to be associated with disease manifestation in hemochromatosis.     

La medicina integrativa en el manejo de la dispepsia funcional. Papel del preparado herbal STW 5

Functional dyspepsia is defined as a group of symptoms, whether related or unrelated to intake, localized in the upper abdomen, that manifest in the form of discomfort or epigastric pain, postprandial fullness and early satiety, in the absence of any demonstrable organic or structural anomaly. The etiopathogenesis and physiopathology of the process are unknown but factors that may be involved include gastric motility disorders, visceral hypersensitivity, psychological and genetic factors, Helicobacter pylori infection, and gastric acid hypersecretion. There is still no etiological treatment and consequently treatment is empirical and based on symptoms. This article reviews the main therapeutic options currently available, with special emphasis on the use of certain phytoceuticals (STW 5), in an attempt to integrate with traditional scientific medicine. This article also proposes an integrative therapeutic algorithm.     

Tratamiento de la hepatitis C en grupos de pacientes especiales

The treatment plan for chronic hepatitis C in special populations varies according to comorbidity and the current evidence on treatment. In patients with hepatitis C virus and HIV coinfection, the results of dual therapy (pegylated interferon plus ribavirin) are poor. In patients with genotype 1 infection, triple therapy (dual therapy plus boceprevir or telaprevir) has doubled the response rate, but protease inhibitors can interact with some antiretroviral drugs and provoke more adverse effects.These disadvantages are avoided by the new, second-generation, direct-acting antiviral agents. In patients who are candidates for liver transplantation or are already liver transplant recipients, the optimal therapeutic option at present is to combine the new antiviral agents, with or without ribavirin and without interferon. The treatment of patients under hemodialysis due to chronic renal disease continues to be dual therapy (often with reduced doses of pegylated interferon and ribavirin), since there is still insufficient information on triple therapy and the new antiviral agents. In mixed cryoglobulinemia, despite the scarcity of experience, triple therapy seems to be superior to dual therapy and may be used as rescue therapy in non-responders to dual therapy. However, a decision must always be made on whether antiviral treatment should be used concomitantly or after immunosuppressive therapy.     

DNA聚合酶η蛋白表达差异与OVCR3细胞顺铂敏感性以及TP方案化疗的卵巢上皮癌患者临床疗效相关性分析

目的：分析DNA聚合酶η蛋白的表达差异与OVCR3细胞顺铂敏感性以及TP方案（紫杉醇＋顺铂）治疗的卵巢上皮癌患者临床疗效的关系。方法：体外培养OVCR3细胞，针对DNA聚合酶η蛋白编码基因的不同部位设计并合成3对靶向小分子RNA，通过脂质体介导瞬时转染OVCR3细胞，采用RT—PCR法比较细胞中DNA聚合酶叽蛋白编码基因表达的差异，采用MTT法检测沉默DNA聚合酶Ⅵ蛋白编码基因细胞对顺铂敏感性的变化。选取我院住院治疗的卵巢上皮癌患者50例，所有患者均为卵巢癌肿瘤细胞减灭术后采用TP方案（紫杉醇＋顺铂）进行一线化疗。采用免疫组化法检测癌组织中的DNA聚合酶η蛋白表达，分析治疗效果与DNA聚合酶η蛋白表达之间的关系。结果：顺铂对OVCR3细胞株以及转染siRNA的OVCR3细胞株的IC50（半数抑制浓度）分别为（46．66±2．23）μmol／L、（30．21±3．09）μmol]L，差异有统计学意义（P〈0．05）。目的蛋白表达差异与近期疗效有关，聚合酶表达强阳性组有效率为46．2％，阳性组有效率为60．0％，阴性组有效率为83.3％，三组比较差异有统计学意义（P〈0．05）。DNA聚合η表达强阳性组中位生存时间为（15．7±3．6）个月，阳性组为（18．5±2．7）个月，阴性组为（28．3±1．9）个月，三组间比较差异有统计学意义（P〈0．05）。结论：抑制DNA聚合η蛋白编码基因能够增加OVCR3细胞对顺铂的敏感性，且DNA聚合η蛋白表诀量与TP方案化疗的沂、沅期疗妁右相关件．     

Films based on the biopolymer poly(3-hydroxybutyrate) as platforms for the controlled release of dexamethasone

Controlled drug delivery aims to achieve an effective drug concentration in the action site for a desired period of time, while minimizing side effects. In this contribution, biodegradable poly(3-hydroxybutyrate) films were evaluated as a reservoir platform for dexamethasone controlled release. These systems were morphological and physicochemically characterized. In vitro release assays were performed for five different percentages of drug in the films and data were fitted by a mathematical model developed and validated by our research group. When the profiles were normalized, a single curve properly fitted all the experimental data. Using this unique curve, the dissolution efficiency (DE), the time to release a given amount of drug (t_X%), and the mean dissolution time were calculated. Furthermore, the dissolution rate, the initial dissolution rate (a%) and the intrinsic dissolution rate were determined. The a% mean value was 1.968 × 10^?2% released/min, t_80% was about 14 days, and the DE was 59.6% at 14 days and 66.5% at 20 days. After 2 days, when approximately 40% of the drug was released, the dissolution rate decreased about 60% respect to the initial value. The poly(3-hydroxybutyrate) platforms behaved as an appropriate system to release and control the dexamethasone delivery, suggesting that they could be an alternative to improve drug therapy.