Magnetic Nanostructures and Stem Cells for Regenerative Medicine, Application in Liver Diseases.

The term "liver disease" refers to any hepatic condition that leads to tissue damage or altered hepatic function and can be induced by virus infections, autoimmunity, inherited genetic mutations, high consumption of alcohol or drugs, fat accumulation, and cancer. Some types of liver diseases are becoming more frequent worldwide. This can be related to increasing rates of obesity in developed countries, diet changes, higher alcohol intake, and even the coronavirus disease 2019 (COVID-19) pandemic was associated with increased liver disease-related deaths. Although the liver can regenerate, in cases of chronic damage or extensive fibrosis, the recovery of tissue mass is impossible, and a liver transplant is indicated. Because of reduced organ availability, it is necessary to search for alternative bioengineered solutions aiming for a cure or increased life expectancy while a transplant is not possible. Therefore, several groups were studying the possibility of stem cells transplantation as a therapeutic alternative since it is a promising strategy in regenerative medicine for treating various diseases. At the same time, nanotechnological advances can contribute to specifically targeting transplanted cells to injured sites using magnetic nanoparticles. In this review, we summarize multiple magnetic nanostructure-based strategies that are promising for treating liver diseases.

Physiologic roles of P2 receptors in leukocytes.

Since their discovery in the 1970s, purinergic receptors have been shown to play key roles in a wide variety of biologic systems and cell types. In the immune system, purinergic receptors participate in innate immunity and in the modulation of the adaptive immune response. In particular, P2 receptors, which respond to extracellular nucleotides, are widely expressed on leukocytes, causing the release of cytokines and chemokines and the formation of inflammatory mediators, and inducing phagocytosis, degranulation, and cell death. The activity of these receptors is regulated by ectonucleotidases-expressed in these same cell types-which regulate the availability of nucleotides in the extracellular environment. In this article, we review the characteristics of the main purinergic receptor subtypes present in the immune system, focusing on the P2 family. In addition, we describe the physiologic roles of the P2 receptors already identified in leukocytes and how they can positively or negatively modulate the development of infectious diseases, inflammation, and pain.

The scientific publication of the Memórias do Instituto Oswaldo Cruz (1909-2020): a history of contribution to the biomedical sciences

BACKGROUND The Memórias do Instituto Oswaldo Cruz (MIOC) is one of the first scientific journals created in Brazil and currently one of the most important biomedical journals in South America. Knowledge of the main themes disseminated over time and its main contributors can contribute towards a better understanding of its trajectory and future. OBJECTIVES Map the journal's scientific publication between 1909 and 2020. METHODS Data from three scientific databases was combined, alongside bibliometrics and network analysis to analyse publication records between 1909 and 2020. FINDINGS Publications increased substantially since the 1980s. The main publishing organisations are Brazilian. Excluding Brazil, the main publishing countries are the USA, Argentina, and Colombia. During the entire investigated period, the main themes refer to Chagas disease, schistosomiasis, and Leishmaniasis. During some periods, publications followed disease outbreaks in Brazil (e.g., dengue fever and yellow fever). MAIN CONCLUSIONS Since its foundation in 1909, the MIOC has focused on infectious and parasitic diseases. The editorial changes implemented from the 1980s onwards led MIOC to a relevant growth concerning annual publications and its transformation into an important communication vehicle for researchers from several Brazilian organisations besides Fiocruz, as well as organisations from other countries, especially within Latin America.

Assessment of the knowledge and perceptions of Brazilian medical residents on transfusion medicine

Abstract Background Medical education has a major social impact because it ultimately influences the quality and safety of the health service offered to the population. Several studies have acknowledged the relationship between medical knowledge on transfusion medicine and the proper use of this therapy. The rational use of blood has become a worldwide concern. In this context, the aim of the present study was to evaluate medical residents' knowledge on transfusion medicine in hospitals located in Rio de Janeiro, Brazil, and their training during their medical education. Methods One hundred and six residents from eight medical specialties of four hospitals participated. A questionnaire developed by the Biomedical Excellence for Safer Transfusion (BEST) group was applied to evaluate the participants' medical knowledge. Another questionnaire was also applied to evaluate participant profiles regarding frequency of transfusion prescriptions, self-perceived knowledge and relevance of the subject. Results The mean number of correct answers to the questionnaire on knowledge about transfusion practices was 43.5% (range: 15-80%). A relationship between training during medical residency and the obtained result was observed (p-value = 0.0007). Most residents (73%) did not receive training in transfusion medicine during their graduation or residency and 93% would like to receive additional training. Conclusion A clear deficit in the knowledge of transfusion medicine was verified, indicating the need for change in the teaching of this specialty. This result is similar to some developed countries.

New Insights in Purinergic Therapy: Novel Antagonists for Uridine 5'-Triphosphate-Activated P2Y Receptors from Brazilian Flora.

P2Y2 and P2Y4 receptors are physiologically activated by uridine 5'-triphosphate (UTP) and are widely expressed in many cell types in humans. P2Y2 plays an important role in inflammation and proliferation of tumor cells, which could be attenuated with the use of antagonists. However, little is known about the physiological functions related to P2Y4, due to the lack of selective ligands for these receptors. This can be solved through the search for novel compounds with antagonistic activity. The aim of this study was to discover new potential antagonist candidates for P2Y2 and P2Y4 receptors from natural products. We applied a calcium measurement methodology to identify new antagonist candidates for these receptors. First, we established optimal conditions for the calcium assay using J774.G8, a murine macrophage cell line, which expresses functional P2Y2 and P2Y4 receptors and then, we performed the screening of plant extracts at a cutoff concentration of 50 µg/mL. ATP and ionomycin, known intracellular calcium inductors, were used to stimulate cells. The calculated EC50 were 11 µM and 103 nM, respectively. These cells also responded to the UTP stimulation with an EC50 of 1.021 µM. Screening assays were performed and a total of 100 extracts from Brazilian plants were tested. Joannesia princeps Vell. (stem) and Peixotoa A. Juss (flower and leaf) extracts stood out due to their ability to inhibit UTP-induced responses without causing cytotoxicity, and presented an IC50 of 32.32, 14.99, and 12.98 µg/mL, respectively. Collectively, our results point to the discovery of potential antagonist candidates from Brazilian flora for UTP-activated receptors.

Domino Hepatocyte Transplantation: A Therapeutic Alternative for the Treatment of Acute Liver Failure.

Background and Aims: Acute liver failure (ALF) is a severe syndrome with an elevated mortality rate, ranging from 40 to 80 %. Currently, liver transplantation is the only definitive treatment for these patients and new therapies aiming to treat ALF include artificial organs implant and stem cells therapy, for example. However, a major limitation of liver donors exists. Living donor liver transplantation (LDLT), split liver transplantation (SLT), and domino liver transplantation (DLT) are some of the available alternatives to treat ALF patients, but these do not reduce the number of patients on waiting lists. Herein, we discuss domino hepatocyte transplantation (DHT) using livers that would not meet transplantation criteria. Methods: We conducted a literature search on PubMed/Medline using acute liver failure, liver transplantation, hepatocyte transplantation, and domino liver transplantation as key words. Results: New sources of biochemically functional hepatocytes and therapeutic treatments, in parallel to organ transplantation, may improve liver injury recovery and decrease mortality rates. Moreover, the literature reports hepatocyte transplantation as a therapeutic alternative for organ shortage. However, a major challenge remains for a wide clinical application of hepatocytes therapy, i.e., the availability of sufficient amounts of cells for transplantation. Ideally, hepatocytes isolated from livers rejected for transplantation may be a promising alternative for this problem. Conclusion: Our review suggests that DHT may be an excellent strategy to increase cell supplies for hepatocyte transplantation.

Pore forming channels as a drug delivery system for photodynamic therapy in cancer associated with nanoscintillators.

According to the World Health Organization (WHO), cancer is one of main causes of death worldwide, with 8.2 million people dying from this disease in 2012. Because of this, new forms of treatments or improvement of current treatments are crucial. In this regard, Photodynamic therapy (PDT) has been used to successfully treat cancers that can be easily accessed externally or by fibre-optic endoscopes, such as skin, bladder and esophagus cancers. In addition, this therapy can used alongside radiotherapy and chemotherapy in order to kill cancer cells. The main problem in implementing PDT is penetration of visible light deeper than 10 mm in tissues, due to scattering and absorption by tissue chromophores. Unfortunately, this excludes several internal organs affected by cancer. Another issue in this regard is the use of a selective cancer cell-photosensitizing compound. Nevertheless, several groups have recently developed scintillation nanoparticles, which can be stimulated by X-rays, thereby making this a possible solution for light production in deeper tissues. Alternative approaches have also been developed, such as photosensitizer structure modifications and cell membrane permeabilizing agents. In this context, certain channels lead to transitory plasma membrane permeability changes, such as pannexin, connexin hemmichannels, TRPV1-4 and P2×7, which allow for the non-selective passage of molecules up to 1,000 Da. Herein, we discuss the particular case of the P2×7 receptor-associated pore as a drug delivery system for hydrophilic substances to be applied in PDT, which could also be carried out with other channels. Methylene blue (MB) is a low cost dye used as a prototype photosensitizer, approved for clinical use in several other clinical conditions, as well as photodynamic therapy for fungi infections.

P2X7 receptor as a novel drug delivery system to increase the entrance of hydrophilic drugs into cells during photodynamic therapy.

The second-generation photosensitizer methylene blue (MB) exhibits photochemical and photophysical properties suitable for photodynamic therapy (PDT)-based cancer treatment. However, the clinical application of MB is limited because of its high hydrophilicity, which hinders its penetration into tumor tissues. Therefore, new methods to improve the entry of MB into the cytoplasm of target cells are necessary. Because MB has a mass of 319 Da, transient pores on the plasma membrane, such as the pore induced by the P2X7 receptor (P2X7R) that allows the passage of molecules up to 900 Da, could be used. Using MTT viability assays, flow cytometry experiments, and fluorescence microscopy, we evaluated the toxicity and phototoxicity of MB and potentiation effects of ATP and MB on cell death processes in the J774 cell line (via a P2X7-associated pore). We observed that treatment with 5 µM MB for 15 min promoted the rate of entry of MB into the cytoplasm to 4.7 %. However, treatment with 5 µM MB and 1 mM ATP for the same amount of time increased this rate to 90.2 %. However, this effect was inhibited by pretreatment with a P2X7 antagonist. We used peritoneal macrophages and a cell line that does not express P2X7R as controls. These cells were more resistant to PDT with MB under the same experimental conditions. Taken together, these results suggest the use of the pore associated with P2X7R as a drug delivery system to increase the passage of hydrophilic drugs into cells that express this receptor, thus facilitating PDT.

Transfusion medicine in medical education: an analysis of curricular grids in Brazil and a review of the current literature

Background Blood transfusions are one of the most performed medical procedures in the world. Thus, as education in transfusion medicine is vital to medical care, it should aim to promote a responsible practice with the rational use of blood by doctors. This study aims to investigate the situation of the teaching of transfusion medicine in medical schools in Brazil. Method The websites of the 249 Brazilian medical schools in operation in June 2015 were visited and the curricula of the medical courses were investigated in respect to the presence or absence of a transfusion medicine discipline. When available, the subject grids were analyzed to verify whether a description of content regarding transfusion medicine was given within other disciplines. Results Of the 249 medical school sites visited, information on the curriculum was obtained from 178. Of the medical schools that published their curriculum, 132 (74.1%) did not have disciplines of transfusion medicine or hematology and only seven (3.9%) had a discipline of transfusion medicine in the curricular grid. Conclusions Education on transfusion medicine is of fundamental importance for safe and efficient transfusion practices. Deficiencies in medical knowledge of this subject have been found worldwide. The results of this study indicate a possible deficiency in teaching the basics of this specialty. Thus, additional prospective studies to assess the knowledge and practice of transfusion medicine in Brazilian medical schools are warranted, which could prompt a discussion on the importance of offering training in transfusion medicine to medical students.

An Improved Method for P2X7R Antagonist Screening.

ATP physiologically activates the P2X7 receptor (P2X7R), a member of the P2X ionotropic receptor family. When activated by high concentrations of ATP (i.e., at inflammation sites), this receptor is capable of forming a pore that allows molecules of up to 900 Da to pass through. This receptor is upregulated in several diseases, particularly leukemia, rheumatoid arthritis and Alzheimer's disease. A selective antagonist of this receptor could be useful in the treatment of P2X7R activation-related diseases. In the present study, we have evaluated several parameters using in vitro protocols to validate a high-throughput screening (HTS) method to identify P2X7R antagonists. We generated dose-response curves to determine the EC50 value of the known agonist ATP and the ICs50 values for the known antagonists Brilliant Blue G (BBG) and oxidized ATP (OATP). The values obtained were consistent with those found in the literature (0.7 ± 0.07 mM, 1.3-2.6 µM and 173-285 µM for ATP, BBG and OATP, respectively) [corrected].The Z-factor, an important statistical tool that can be used to validate the robustness and suitability of an HTS assay, was 0.635 for PI uptake and 0.867 for LY uptake. No inter-operator variation was observed, and the results obtained using our improved method were reproducible. Our data indicate that our assay is suitable for the selective and reliable evaluation of P2X7 activity in multiwell plates using spectrophotometry-based methodology. This method might improve the high-throughput screening of conventional chemical or natural product libraries for possible candidate P2X7R antagonist or agonist.

Aprendizagem baseada em problemas: uma proposta para a formação de técnicos em laboratórios de saúde pública / Problem-based learning: a proposal for the training of students as public health laboratory technicians / Aprendizaje basado en problemas: una propuesta para la formación de técnicos en laboratorios de salud pública

No âmbito da formação profissionalizante, as características da aprendizagem baseada em problemas (ABP)propiciam uma maior aproximação dos alunos da prática profissional. Este artigo apresenta uma propostacurricular inovadora para a formação de técnicos em laboratórios de saúde pública, fundamentada na ABP. Alógica da estrutura curricular apoia-se em dois eixos estruturantes: 1) as principais tecnologias utilizadas noslaboratórios de saúde pública, tais como a microscopia, a volumetria, a espectrofotometria, a cromatografiae a eletroforese; e 2) as principais matrizes utilizadas nos laboratórios, tais como a água, os alimentos,a urina, as fezes e o sangue. Com esta proposta, busca-se fomentar discussões acerca da implantação decurrículos e de estratégias de ensino que possam contribuir para melhorar o ensino profissionalizante noBrasil, assim como promover a formação de técnicos capazes de atuarem nos laboratórios que compõem oSistema Nacional de Laboratórios de Saúde Pública (SISLAB)...

In the context of vocational training, the characteristics of the problem-based learning (PBL) provide agreater proximity of the students to professional practice. This article presents an innovative curriculumproposal for the training of technicians in public health laboratories, based on PBL. The logic of thecurriculum structure is based on two axes: 1) The main technologies applied at public health laboratories,such as microscopy, volumetry, spectrophotometry, chromatography and electrophoresis; and 2) The mainmatrices used in laboratories, such as water, food, urine, faeces and blood. With this proposal, we seek tofoster discussions about the curriculum implementation and the teaching strategies that can contribute tothe improvement in vocational education in Brazil, as well as promote the training of technicians capable ofworking in laboratories comprising the Brazilian National Public Health Laboratory (SISLAB)...

En el ambito de la formación profesional, el aprendizaje basado en problemas (ABP) permite una mayoraproximación de los estudiantes a la práctica para habilitarse en una profesión. Este artículo presenta unapropuesta curricular inovadora para la formación de técnicos en laboratórios de salud pública, basada enABP. La lógica de la estructura curricular se sustenta en dos ejes: 1) Las principales tecnologías utilizadas emlos laboratorios de salud pública tales como, microscopia, volumetría, espectrofotometría, cromatografíay electroforesis; y 2) Las principales matrices utilizadas en los laboratorios, como agua, alimentosy fluidos biológicos en general. Con esta propuesta se busca el fomento de discusiones com respecto ala implementación de currículos y de estratégias de enseñanza que puedan contribuir a la enseñanzaprofesional en Brasil al igual que promover la formación de técnicos capaces de actuaren en los laboratóriosque componen el Sistema Nacional de Laboratorios de Salud Pública (SISLAB)...

The P2X7 receptor: shifting from a low- to a high-conductance channel - an enigmatic phenomenon?

The general structure of the P2X7 receptor (P2X7R) is similar to the structure of other P2X receptor family members, with the exception of its C terminus, which is the longest of this family. The P2X7R activates several intracellular signaling cascades, such as the calmodulin, mitogen-activated protein kinase and phospholipase D pathways. At low concentrations of ATP (micromolar range), P2X7R activation opens a cationic channel, similarly to other P2X receptors. However, in the presence of high concentrations of ATP (millimolar range), it opens a pathway that allows the passage of larger organic cations and anions. Here, we discuss both the structural characteristics of P2X7R related to its remarkable functions and the proposed mechanisms, including the dilation of the endogenous pore and the integration of another channel. In addition, we highlight the importance of P2X7R as a therapeutic target.

Structural and molecular modeling features of P2X receptors.

Currently, adenosine 5'-triphosphate (ATP) is recognized as the extracellular messenger that acts through P2 receptors. P2 receptors are divided into two subtypes: P2Y metabotropic receptors and P2X ionotropic receptors, both of which are found in virtually all mammalian cell types studied. Due to the difficulty in studying membrane protein structures by X-ray crystallography or NMR techniques, there is little information about these structures available in the literature. Two structures of the P2X4 receptor in truncated form have been solved by crystallography. Molecular modeling has proven to be an excellent tool for studying ionotropic receptors. Recently, modeling studies carried out on P2X receptors have advanced our knowledge of the P2X receptor structure-function relationships. This review presents a brief history of ion channel structural studies and shows how modeling approaches can be used to address relevant questions about P2X receptors.

A transformação curricular e a escolha da especialidade médica / The transformation to the medical curriculum and choosing a medical specialization

A reforma curricular implantada em 2005 no curso de graduação em Medicina do Centro Universitário Serra dos Órgãos (Unifeso) com a utilização das metodologias ativas de ensino-aprendizagem, no caso a aprendizagem baseada em problemas (ABP), e com a passagem pela Unidade Básica de Saúde da Família (UBSF) desde os primeiros períodos pode influenciar a trajetória de formação profissional de seu estudante? Para responder a esta questão - objetivo deste estudo -, procedeu-se a uma pesquisa qualitativa com os discentes matriculados no quinto período do curso, por meio de entrevistas, as quais foram categorizadas e analisadas. Os resultados evidenciaram significativa receptividade ao novo modelo curricular, pelo entendimento de que este é capaz de suscitar novas reflexões dirigidas à futura prática do estudante, e, igualmente, ao conceito de saúde e ao processo de adoecimento. Verificou-se, ainda, que a opção precoce por uma especialidade, expressa pela maior parte dos entrevistados, não foi alterada sob o novo currículo e que a formação do médico como generalista ou médico de família é ainda pouco valorizada.

This paper asks whether the curriculum change implemented in 2005 to the Centro Universitário Serra dos Órgãos (Unifeso) Undergraduate Medical Course may influence the course of its students' vocational training, through its active teaching and learning methodologies, such as problem-based learning (PBL) and the students' passage through the Primary Care Unit (PCU) in the early years of the course. To answer this objective question, qualitative research was carried out on medical students in the fifth semester, by means of interviews which were categorized and later analyzed. The results showed significant receptivity to the new curriculum model, due to the understanding that such a model is able to inspire new reflections on future student practice and also on the concept of health and the process taken by illnesses. The study also showed that the early option to choose a particular specialization - taken up by the majority of respondents - had not changed under the new curriculum and that the training of medical practitioners or family physicians is still poorly regarded.

Uma abordagem sobre o uso de medicamentos nos livros didáticos de biologia como estratégia de promoção de saúde / An approach regarding the use of medication in biology textbooks as a strategy for health promotion

O uso inadequado de medicamentos constitui uma grande ameaça à saúde pública e os medicamentos ocupam a primeira posição dentre os agentes causadores de intoxicação no Brasil, à frente de venenos para roedores e insetos, drogas ilícitas, agrotóxicos, produtos de limpeza e alimentos estragados. Os Parâmetros Curriculares Nacionais do Ensino Médio (PCN+) dão grande ênfase à saúde, uma vez que encontramos o tema Medicamentos mencionado repetidas vezes em seus conteúdos. O objetivo da pesquisa foi estudar as abordagens sobre o uso de medicamentos nos livros didáticos. Foram analisados onze livros didáticos de biologia, sendo seis constituídos de volumes únicos e cinco com três volumes cada, num total de vinte e um volumes. O uso racional de medicamentos deve ser considerado um tópico importante da promoção da saúde que atinge todos os setores da sociedade, devendo ser enfatizado na educação básica. Diante disso, e com base nos presentes resultados, sugerimos que os livros didáticos analisados sejam adequados às novas legislações e que os conteúdos o URM, atendendo assim as recomendações dos PCN+. Para tanto, os livros poderiam tratar de forma concisa os temas: automedicação, adesão ao tratamento medicamentoso, propagandas e reportagens sobre medicamentos entre outros.

The inappropriate use of medication represents a major threat to public health and drugs rank first among the agents causing intoxication in Brazil, ahead of poisons for rodents and insects, illegal drugs, pesticides, cleaning products and spoiled food. The National Curriculum of Secondary Education Parameters (PCN+) give major emphasis to health, since the reference to Drugs is mentioned repeatedly in the text. The scope of this research was to study the approaches to drug use in textbooks. For this purpose, eleven biology textbooks were analyzed, namely six single volumes and five with three volumes each, i.e. a total of twenty-one volumes. The rational use of medication should be considered an important topic for the promotion of health which affects all sectors of society and should be emphasized in basic education. In line with this idea and based on the results obtained, it is suggested that the textbooks analyzed should be adapted to the new legislation and content that addresses Rational Drug Use, thus meeting the recommendations of PCN+. In this context, the books should concisely address the following topics: self-medication, adherence to drug treatment, advertisements and reports on drugs, among others.

Modulation of P2 receptors on pancreatic ß-cells by agonists and antagonists: a molecular target for type 2 diabetes treatment.

Morbidity and mortality from diabetes mellitus (DM) are serious worldwide concerns. By the year 2030, the estimated number of diabetic patients will reach a staggering 439 million worldwide. Diabetes mellitus type 2 (DM2), which involves disturbances in both insulin secretion and resistance, is the most common form of diabetes and affects approximately 5 to 7% of the world's population. When a patient with DM2 cannot regulate his or her blood glucose levels through diet, weight loss, or exercise, oral medications, such as hypoglycemic agents (i.e., sulphonylureas, biguanides, alpha glucosidase inhibitors and thiazolidinediones), are crucial. Here, we discuss some physiological aspects of P2 receptors on pancreatic ß-cells, which express a variety of P2 receptor isoforms. These receptors enhance glucose-dependent insulin release. In addition, we speculate on the potential of purinergic compounds as novel or additional treatments for Type 2 Diabetes mellitus.

Formação médica na estratégia de saúde da família: percepções discentes / Medical training in the family health strategy: student's perceptions

Diante das atuais demandas sociais, tornou-se imprescindível para a educação médica a transição do modelo tradicional de formação reducionista e hospitalocêntrica para uma vertente de educação mais ampla e integralizada. A construção de novas práticas de formação em saúde - com a utilização de cenários externos -, em coparticipação com o SUS, tem assumido um papel fundamental na formação médica. Em 2005, o Centro Universitário Serra dos Órgãos (Unifeso) incorporou em seu currículo a Aprendizagem Baseada em Problemas e a inserção dos graduandos de Medicina em Unidades Básicas de Saúde da Família. Este artigo apresenta a percepção dos discentes de Medicina neste cenário. Para isto, realizou-se uma pesquisa qualitativa, utilizando-se entrevistas e análise temática das respostas, com a criação de categorias. Os resultados demonstram a combinação de impressões positivas - integração entre teoria e prática - e negativas - problemas na organização das atividades e necessidade de identificação de um preceptor local. Propõe-se um planejamento orientado pelas novas diretrizes para o ensino na Atenção Primária à Saúde, contextualizada à condição da integralidade.

Given current social demands, it has become essential for medical education to break from the traditional model of biological reductionist and training based only at hospitals and redefine itself towards a holistic care (integrality). The construction of new training practices in health with the use of new outdoor scenarios, in partnership with (Unified National Health System - SUS), assumed a key role. In 2005 the Centro Universitário Serra dos Órgãos (Unifeso) incorporated into its curriculum the Problem-Based Learning and the insertion of medical undergraduates into Basic Health Units Family. This paper describes the perception of medical students in this scenario. We conducted a qualitative research working from the application of interviews and the utilization of thematic analysis of responses with the creation of categories. The results show the combination of positive impressions - integration between theory and practice - and negative - problems in the organization of activities, as well as the necessity to identify a local preceptor. A plan is proposed, guided by the new Directives, for teaching in the primary health care in the context of the condition of integrality.

A consensus segment in the M2 domain of the hP2X(7) receptor shows ion channel activity in planar lipid bilayers and in biological membranes.

The P2X(7) receptor (P2X(7)R) is an ATP-gated, cation-selective channel permeable to Na(+), K(+) and Ca(2+). This channel has also been associated with the opening of a non-selective pore that allows the flow of large organic ions. However, the biophysical properties of the P2X(7)R have yet to be characterized unequivocally. We investigated a region named ADSEG, which is conserved among all subtypes of P2X receptors (P2XRs). It is located in the M2 domain of hP2X(7)R, which aligns with the H5 signature sequence of potassium channels. We investigated the channel forming ability of ADSEG in artificial planar lipid bilayers and in biological membranes using the cell-attached patch-clamp techniques. ADSEG forms channels, which exhibit a preference for cations. They are voltage independent and show long-term stability in planar lipid bilayers as well as under patch-clamping conditions. The open probability of the ADSEG was similar to that of native P2X(7)R. The conserved part of the M2 domain of P2X(7)R forms ionic channels in planar lipid bilayers and in biological membranes. Its electrophysiological characteristics are similar to those of the whole receptor. Conserved and hydrophobic part of the M2 domain forms ion channels.

Ensino médico, SUS e início da profissão: como se sente quem está se formando? / Medical education, the Unified Health System, and the early profession: what do graduating students feel?

A construção do SUS e o crescimento do nosso país têm suscitado uma discussão maior sobre mudanças no ensino médico. Iniciativas para implementar as Diretrizes Curriculares Nacionais aumentam o cardápio de estratégias de mudanças na preparação do fu turo médico. Para compreender melhor essas modificações, aplicamos questionários in locu a 1.004 alunos do internato de Medicina em 13 cursos médicos de seis Estados brasileiros entre 2004 e 2007, e realizamos entrevistas com alunos, docentes e gestores de Saúde. Neste artigo, destacamos o que pensam os formandos a respeito de sua formação no começo de sua atuação profissional. Aproximadamente 19 por cento dos alunos se sentem aptos ao exercício imediato da medicina; 81 por cento querem buscar formação complementar; 63 por cento desejam ser "especialistas"; só 20 por cento querem trabalhar em medicina geral, como o PSF, e apenas 5 por cento querem trabalhar em pequenos municípios. Há discrepâncias entre o que os alunos querem fazer, como se sentem preparados e o que acabarão por fazer. Este estudo fornece dados que podem ajudar na melhoria da educação médica de acordo com as demandas do SUS e na integração ensino-serviços-comunidade.

The construction and consolidation of the Unified Health System (SUS) in Brazil and the country's economic growth have sparked increasing discussion on changes in medical education. Initiatives to implement the National Curriculum Guidelines have expanded the range of strategies for changes in training for future physicians. In order to better understand these changes, we applied on-site questionnaires to 1,004 medical interns in 13 medical schools in six States of Brazil from 2004 to 2007, and conducted interviews with students, faculty, and health administrators. This article highlights what graduating medical students think of their training at the beginning of their professional careers. Approximately 19 percent of the graduates feel prepared to practice medicine immediately; 81 percent want to seek additional training; 63 percent wish to become "specialists"; and only 20 percent want to work in general practice like the Family Health Program (only 5 percent want to work in small towns). There are discrepancies between what the students want to do, how prepared they feel, and what they actually end up doing. This study provides data that can help improve medical education in Brazil according to the demands of the Unified Health System and integration between teaching, services, and the community.

Large-conductance channel formation mediated by P2X7 receptor activation is regulated through distinct intracellular signaling pathways in peritoneal macrophages and 2BH4 cells.

The P2X(7) receptor (P2X7R) is a ligand-gated ATP receptor that acts as a low- and large-conductance channel (pore) and is known to be coupled to several downstream effectors. Recently, we demonstrated that the formation of a large-conductance channel associated with the P2X(7) receptor is induced by increasing the intracellular Ca(2+) concentration (Faria et al., Am J Physiol Cell Physiol 297:C28-C42, 2005). Here, we investigated the intracellular signaling pathways associated with P2X(7) large-conductance channel formation using the patch clamp technique in conjunction with fluorescent imaging and flow cytometry assays in 2BH4 cells and peritoneal macrophages. Different antagonists were applied to investigate the following pathways: Ca(2+)-calmodulin, phospholipase A, phospholipase D, phospholipase C, protein kinase C (PKC), mitogen-activated protein kinase (MAPK), MAPK/extracellular signal-regulated kinase, phosphoinositide 3-kinase (PI3K), and cytoskeletal proteins. Macroscopic ionic currents induced by 1 mM ATP were reduced by 85% in the presence of PKC antagonists. The addition of antagonists for MAPK, PI3K, and the cytoskeleton (actin, intermediary filament, and microtubule) blocked 92%, 83%, and 95% of the ionic currents induced by 1 mM ATP, respectively. Our results show that PKC, MAPK, PI3K, and cytoskeletal components are involved in P2X(7) receptor large-channel formation in 2BH4 cells and peritoneal macrophages.