Temperature, air pollution, and mortality from myocardial infarction in São Paulo, Brazil

An increase in daily mortality from myocardial infarction has been observed in association with meteorological factors and air pollution in several cities in the world, mainly in the northern hemisphere. The objective of the present study was to analyze the independent effects of environmental variables on daily counts of death from myocardial infarction in a subtropical region in South America. We used the robust Poisson regression to investigate associations between weather (temperature, humidity and barometric pressure), air pollution (sulfur dioxide, carbon monoxide, and inhalable particulate), and the daily death counts attributed to myocardial infarction in the city of São Paulo in Brazil, where 12,007 fatal events were observed from 1996 to 1998. The model was adjusted in a linear fashion for relative humidity and day-of-week, while nonparametric smoothing factors were used for seasonal trend and temperature. We found a significant association of daily temperature with deaths due to myocardial infarction (P < 0.001), with the lowest mortality being observed at temperatures between 21.6 and 22.6ºC. Relative humidity appeared to exert a protective effect. Sulfur dioxide concentrations correlated linearly with myocardial infarction deaths, increasing the number of fatal events by 3.4 percent (relative risk of 1.03; 95 percent confidence interval = 1.02-1.05) for each 10 µg/m increase. In conclusion, this study provides evidence of important associations between daily temperature and air pollution and mortality from myocardial infarction in a subtropical region, even after a comprehensive control for confounding factors.

Quantitative ultrastructural changes induced by sucrose administration in the pancreatic B cells of normal hamsters

We have previously reported that young male Syrian hamsters receiving a sucrose-rich diet presented increased B-cell replication rate and size. The aim of the present study was to analyze, under the same experimental conditions, the ultrastructural changes in B cells. For this purpose, young male Syrian hamsters were fed with a commercial diet and 10 sucrose in their drinking water (S group) while the control group (C) received the same diet and tap water, for 5 weeks. Samples of the pancreas removed after that period were processed for the immunohistochemical identification of B cells as well as for measuring several ultrastructural parameters. S hamsters showed higher serum insulin levels, while similar serum glucose values were obtained in animals from both groups. The B cells from S group exhibited lesser number of dense secretory granules at expenses of an increase of the pale ones, increased number of both exocytosis profiles and fusion-granule images, as well as enlargement of the intercellular space and mitochondrial area. Marked expansions of this space, limited by junctional complexes, were observed between adjacent B cells. These results would indicate that sucrose administration to normal hamsters not only increases the pancreatic B-cell mass but also induces measurable subcellular changes in the individual B-cell characteristic of an enhanced secretory activity. The present model would represent a useful tool for testing strategies in preventing the damage or promoting the recovery of the pancreatic B cells.

Ultrastructural study of the endocrine pancreas of the toad Bufo arenarum

The aim of the present report was to identify by electron microscopy the different endocrine cell types of the toad pancreas. Thus, we studied the pancreas from male specimens of Bufo arenarum with routine techniques for transmission electron microscopy. The results showed the presence of four endocrine cells types which would correspond to those responsible for the different pancreatic hormonal secretions in other species (B, A, D and PP cells). Type 1 cells contained rounded secretory granules with a clear halo which responded to two varieties: a) measuring 200 to 400 mm, and b) having a crystalloid core and a diameter of 400 to 600 nm; these cells would correspond to B cells showed rounded or irregular granules of 104 to 400 nm; they would be equivalent to A cells. Type 3 cells presented polymorphic ganules, most of them peanut-shaped, measuring 115 to 850 nm; they would resemble D cells. Finally, Type 4 cells contained rounded granules of 80 to 400 nm; these cells would correspond to PP cells. In addition, we also observed mixed cells exhibiting similar characteristics to acinar cells, but containing secretory granules resembling those found in some of the endocrine cell types; these would correspond to the acinar-islet cells reported in other animals. In conclusion, we described the ultrastructure of the toad endocrine pancreas and compare it with previous observations made in other amphibians.

Trombose em artérias coronárias normais causando infarto agudo do miocárdio em pacientes alcoólatra / Thrombosis in normal coronary arteries causing acute myocardial infarction in an alcoholic patient

Paciente jovem, etilista, que sofreu infarto agudo do miocárdio. Após terapêutica trombolítica sem sucesso, a cineangiocoronariografia na fase aguda evidenciava trombos em múltiplas artérias. Um 2§ CATE, realizado no 7§ dia de internação revelou coronárias normais. Não havia nenhum distúrbio do metabolismo lipídico, assim como outro fator de risco de doença arterial coronária, a não ser o fato de ser tabagista de oito a 10 cigarros ao dia, há dois anos, o que nos levou a acreditar que o abuso de álcool etílico possa ter contribuído para esse evento.

Slow coronary run-off in patients with angina pectoris: clinical significance and thallium-201 scintigraphic study

To determine whether or not slow coronary flow (SF) depends on hemodynamic variables, we studied 17 patients (15 men, mean age = 47.8 years) with SF at coronariography. Exercise thallium-201 myocardial scintigraphy revealed perfusion abnormalities in 13 (76.4 per cent) patients. We then selected 89 individuais submitted to cinecoronariography for comparison: 15 were normal and 74 had heart disease. The coronary flow velocity was evaluated by the number of heart beats (HB) needed for coronary artery dye filling. The patients in the SF group had normal hemodynamic variables which were significantly different from those of patients with heart disease (P = 0.001). Patients with heart disease needed no more than 4 HB to fill their arteries, in contrast to 6.88 ñ 1.68 (5 to 11) in the SF group (P<0.OOO1). Thus, in our patients with myocardial scintigraphy suggesting ischemia, SF was found to be an event which did not depend on hemodynamic factors.

Estudo comparativo entre Verapamil e Adenosina-Trifosfato no tratamento das taquicardias paroxísticas supraventriculares / Adenosin-three phosphate compared with Verapamil to treat paroxysmal supraventricular tachycardia

Objetivo - comparar a eficácia e segurança da adenosina-trifosfato (ATP) e verapamil endovenosos na reversäo das taquicardias paroxísticas supraventriculares (TPSV). Métodos - foram analisados 50 pacientes com diagnóstico de TPSV pelo eletrocardiograma convencional. Excluíram-se aqueles com insuficiência cardíaca, quadro isquêmico agudo, uso de dipiridamol e metilxantinas. Os pacientes foram distribuídos por sorteio em dois grupos: A) ATP em bolo de 10 ou 20 mg; V) verapamil em infusäo rápida de at15 mg. Avaliaram-se sucesso, tempo de reversäo, dose empregada e efeitos colaterais. Resultados - Ocorreu sucesso na reversão em 96% do grupo A e em 92 % do grupo V (p= 1,0). O tempo médio de reversão foi de 30s no grupo A e 248s no V. Efeitos colaterais foram encontrados em 33% no grupo A, e não ocorreram no grupo V Conclusão - O ATP é uma opção atraente para a reversão das TPSV, apresentando efeitos colaterais fugazes, podendo ser droga de escolha no tratamento desses episódios na presença de disfunção ventricul

Purpose - To evaluate the efficacy and safety of intravenous (IV) adenosine-triphosphate (ATP) and verapamil to convert acute episodes of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm. Methods - Fifty patients with PSVT were randomized in two groups: A) 25 treated with IV bolus of ATP (10 or 20mg), and V) 25 treated with IV verapamil, up to 15mg, during 3min. We evaluated the time delay necessary to convert the arrhytmia, doses, and side-effects. Patients with acute ischemic syndromes (<3 weeks), severe congestive heart failure, and treatment with dipyridamole or methylxanthine were excluded. Results - There were no differences between the two groups regarding to age, sex, and success rate. The average time till reversal were respectively, 30s and 248s for ATP and verapamil. Ventricular ectopy and general disconfort were observed in 33% of patients receiving ATP, where as no side-effects occurred in group V. Conclusion - ATP is a good option to convert rapidly PSVT to sinus rhythm and, probably, could be the first choice to treat PSVT patients with ventricular dysfunction

Estructura y ultraestructura del pancreas endocrino de ratones transgenicos diabeticos / Structure and ultrastructure of the endocrine pancreas in diabetic transgenic mice

El objetivo del trabajo fue corroborar los cambios estructurales y determinar las alteraciones ultraesctructurales ocurridas en el páncreas endocrino de ratones con un síndrome inducido de diabetes mellitus insulinodependiente (DMID). Para ello se utilizaron ratones transgénicos (OVE 27) que sobreexpresan el gen de calmodulina en las células beta del páncreas endocrino; en estos animales, el aumento de calmodulina disminuye los niveles de calcio citosólico de las células beta, produciendo alteraciones morfológicas y funcionales que desencadenan una DMID de curso severo. Para nuestro estudio se obtuvieron y procesaron porciones del páncreas (cola) de 4 ratones transgénicos machos diabéticos de 5 semanas de edad (glucemia: 376 + 2 mg/del) y de 4 controles no transgénicos de la misma cepa, sexo y edad (glucemia: 113 + 13 mg/dl). El estudio inmunohistoqu­mico con microscop­a de luz confirmó que los ratones transgénicos presentan una disminución del número y tama o de los islotes con distorsión de su arquitectura, sin respuesta inflamatoria asociada. Los estudios ultraestructurales demostraron diversos grados de da o en las células Beta, tales como la presencia de interdigitaciones de membrana y alteraciones de sus organelas y de sus gránulos de secreción. Estos hallazgos coinciden con el deterioro cuantitativo y funcional de las células beta y la conservación de las problaciones celulares no-beta de los islotes. Estos cambios ultraestructurales en las células beta del páncreas del modelo experimental estudiado, sumados a las alteraciones inmunohistoquímicas previamente descriptas, contribuyen a explicar la manifestación de la diabetes.

Beneficial effect of long-term use of a beta-blocker in patients before acute myocardial infarction

The outcome of 38 beta-blocker users (group BB, 28 men and 10 women with a mean age of 56 ñ 4 years) was compared to that of 100 non-users (group NU, 69 men and 31 women with mean age of 57 ñ 8 years) after acute myocardial infarction (AMI). The two groups were compared in terms of electrocardiographic (EKG) location of the AMI (anterior, inferior and lateral), EKG Q and non-Q wave infarction, clincial functional class of Forrester, serum cratine phosphokinase MB fraction (CKMB) peak release and intrahospital mortality.There were no differences between groups concerning sex or severity of coronary artery disease bath arterial hypertension was 3-fold more prevalent group BB. The EKG location of the AMI was similar int he two groups. Non-Q infarction was significantly more prevalent in group BB (37 percent) than in group NU (5 percent). The incidence of clinical functional class IV of Forrester and the serum CKMB peaks were significantly lower in goup BB (2.6 percent vs 16.0 percent and 53 ñ 3 vs 68 ñ 9 UI/1, respectively. Intrahospital mortality was also significantly lower in group BB (2.6 percent) than in group NU (10 percent). These data suggest the beneficial effect of previous long-term use of beta-blockers as indicated by a lower incidence of cardiogenic shock and a significant decrease in intrahospital mortality after AMI

Doenças da aorta / Aorta disease

A aorta normal é responsável pela conduçÝo de quase 200.000.000 de litros de sangue e por receber o impacto de aproximadamente três bilhSes de batimentos cardíacos durante a vida. este grande vaso é uma estrutura de condutância e de resistência, composto por uma túnica interna - a íntima - uma externa - a adventícia - e pela túnica média. Na túnica média se encontra uma grande quantidade de fibras elásticas, apostas em forma de espiral, dando a esse órgÝo uma grande capacidade de absorver tensSes e elasticidade, fundamentais para a onda de pulso, que permite a manutençÝo de fluxo no sistema arterial, na fase diastólica do coraçÝo. Na porçÝo ascendente e no arco estÝo os pressoceptores que enviam estímulos ao centro vasomotor do tronco cerebral (exemplo: seio carotídeo), desempenhando importante papel no controle da pressÝo arterial. Anatomicamente a aorta é subdividida em três partes: a ascendente, a crossa ou arco e a descendente. A ascendente tem no adulto em torno de 3 cm de diâmetro, se estendendo da base do coraçÝo, onde se situa dentro do saco pericárdico, em direçÝo cefálica, com comprimento entre 5 e 6 cm, onde se une ao arco aórtico. Neste percurso, levemente à direita da linha média, relaciona-se com o tronco da artéria pulmonar à sua frente e atrás com o átrio esquerdo, o brônquio fonte direito e o ramo direito da artéria pulmonar. O arco aórtico tem orientaçÝo ântero-posterior e dele emergem todos os ramos braquiocefálicos. Encontra-se no mediastino supeiror e se relaciona com os nervos frênicos, vago e o laríngeo recorrente esquerdo. A aorta descendente é a continuaçÝo do arco e se coloca à esquerda da coluna vertebral no mediastino posterior, depois se anterioriza em relaçÝo a coluna vertebral, ficando atrás do esôfago, e transpassa o diafragma ao nível da 12 vértebra torácica. As porçSes ascendente e crossa nÝo sÝo fixadas a estruturas torácicas, ao passo que a descendente o é pelas reflexSes das pleuras e pelas saídas das artérias intercostais. Por esse motivo, a regiÝo do istmo (junçÝo entre crossa e descendente) é o local mais frequente de ruptura em casos de trauma, além de ser o local onde ocorre a coartaçÝo. Na regiÝo abdominal originam-se todos os ramos esplâncnicos e a aorta se bifurca ao nível da quarta vértebra lombar.

Islet cell population changes induced by short term ovariectomy

En este trabajo se han estudiado los cambios ocurridos en el páncreas endocrino de ratas 14 días después de su ovariectomía. Se emplearon para ello ratas ovariectomizadas (O) y controles normales (C) de la misma edad. Los páncreas de estos animales se tiñeron empleando técnicas de p-aldehído-fucsina y peroxidasa (con suero antiinsulina) y el método de Weibel para las determinaciones morfométricas. Los resultados obtenidos indican que la ovariectomía produce una disminución del volumen total del páncreas endocrino, acompañado de un aumento del volumen individual de los islotes. Este último sería debido a un incremento de su población celular a expensas de sus células B sin cambio en el tamaño de ellas, indicando una probable hiperplasia sin hipertrofia celular. Estos cambios explicarían la aparente discordancia del efecto de la castración sobre la secreción de insulina cuando ésta se estudia en modelos de páncreas entero o islotes aislados

Amiodarona injetável no tratamento das arritmias supraventriculares: resultados imediatos / Intravenous amiodarone in the treatment of supraventricular arrhythmias: immediate results

Sessenta e cinco pacientes de taquiarritmias supraventriculares,que nao apresentavam insuficiencia cardiaca funcional III e IV (NHA), foram medicados com amiodarona intravenosa na dose de 5 mg/kg, injectada durante 30 s. Repetia-se uma dose de 2,5 mg/kg caso nao houvesse, apos 15 min reversao para ritmo sinusal (RS).Apos 30 min conforme a resposta classificava-se o paciente nos seguintes grupos: 1 - reversao para RS; 2 - diminuicao da frequencia ventricular de pelo menos 20% da inicial; 3 inalterado. Os grupos 1 e 2 eram considerados como de sucesso terapeutico. Dos 65 casos, 24 apresentavam taquicardia paroxistica supraventricular, neles ocorrendo 18 sucessos(75%); 10 tinham flutter atrial e neles foram obtidos 3 sucessos (30%); 31 apresentavam fibrilacao atrial, com 24 sucessos (77%). Nenhum caso de fibrilacao atrial reverteu para ritmo sinusal. Efeitos indesejaveis ocorreram em 5 (7,6%) pacientes: 3 tiveram sensacao de mal estar geral um, bradicardia sinusal sintomatica e um, edema agudo de pulmao. Conclui-se que a amiodarona intravenosa e uma opao terapeutica para o tratamento das taquiarritmias supreventriculares em pacientes que nao apresentem insuficiencia cardiaca importante

Origem anomala da arteria descendente anterior em arteria coronaria direita. Relato de dois casos / Anomalous origin of the anterior descending from the right coronary artery.Report of 2 cases

O significado clinico de determinadas anomalias coronarias ainda esta esclarecido. Sao relatados casos incomuns de dois pacientes com origem anomala da arteria descendente anterior em coronaria direita, com trajeto subpulmonar. Ambos apresentavam certas evidencias de alteracoes isquemicas, traduzidas pela sintomatologia, manifestacoes eletricas ou cintilografia miocardica. O mecanismo fisiopatologico da isquemia miocardica que possa advir anomalia e obscuro