José Martins dos Santos

O parênquima pulmonar do rato Wistar exposto a ruído de baixa frequência

RESUMO Em estudos previos do aparelho respiratorio realizados em ratos expostos a ruido de baixa frequencia (RBF), observaram-se lesoes irreversiveis do epitelio respiratorio. Um dos aspectos mais notaveis destas lesoes diz respeito as imagens das microvilosidades das celulas em escova que apresentam alteracoes importantes na distribuicao e na morfologia. Este estudo e dirigido as populacoes celulares dos alveolos pulmonares de ratos expostos a RBF em comparacao com ratos mantidos em silencio. Dez ratos Wistar foram expostos continuadamente a 2160 horas de RBF e sacrificados apos uma semana em silencio. Dez ratos de controlo, do mesmo grupo etario, foram mantidos em condicoes identicas mas em silencio. Todos os animais foram tratados de acordo com a norma 86/609/CE. Fragmentos do parenquima pulmonar foram recolhidos e processados para microscopia optica e electronica de varrimento. Nos ratos expostos, as paredes alveolares apresentam-se grosseiramente espessadas e a estrutura distorcida ou mesmo apagada. Os macrofagos sao extremamente frequentes nos ratos expostos, embora tambem se observem em menor numero nos ratos de controlo. As paredes dos vasos estao espessadas e os pneumocitos de tipo I sao raros. Em contraste, os de tipo II tornam-se na populacao celular alveolar mais frequente e importante. Nestas celulas, as microvilosidades distribuem-se irregularmente. Ainda nos pneumocitos tipo II, observa-se com grande frequencia “buracos negros” na superficie. Observam-se ainda 2 tipos de celulas em escova: as intersticiais e as externas. Nos ratos expostos, as microvilosidades destas celulas apresentam-se fundidas. O RBF exerce uma accao nociva sobre o parenquima pulmonar. REV PORT PNEUMOL 2004; X (1): 77-85

Tracheal transplantation: cytological changes studied by scanning and transmission electron microscopy in the rabbit.

Objectives Our goal was to offer a comprehensive cytological study of the changes in the trachea after experimental transplantation of the organ.

Histomorphometric Evaluation of the Small Coronary Arteries in Rats Exposed to Industrial Noise

Morphological changes induced by industrial noise (IN) have been experimentally observed in several organs. Histological observations of the coronary arteries showed prominent perivascular tissue and fibrosis among IN-exposed rats. The effects on the small arteries are unknown. Objective: To evaluate the histomorphometric changes induced by IN on rat heart small arteries. Methods: Twenty Wistar rats exposed to IN during a maximum period of seven months and 20 age-matched controls were studied. Hearts were transversely sectioned from ventricular apex to atria and a mid-ventricular fragment was selected for analysis. The histological images were obtained with an optical microscope using 400× magnifications. A total of 634 arterial vessels (298 IN-exposed and 336 controls) were selected. The mean lumen-to-vessel wall (L/W) and mean vessel wall-to-perivascular tissue (W/P) ratios were calculated using image J software. Results: There were no differences between exposed and control animals in their L/W ratios (p = 0.687) and time variations in this ratio were non-significant (p = 0.110). In contrast, exposed animals showed lower W/P ratios than control animals (p < 0.001), with significant time variations (p = 0.004). Conclusions: Industrial noise induced an increase in the perivascular tissue of rat small coronary arteries, with significant development of periarterial fibrosis.

Brugada Pattern, Brugada Phenocopy, What to Think?

Propafenone is a class 1 anti-arrhythmic medication with beta-adrenergic and calcium channel blocker properties. B r u g a d a s y n d r o m e ( B r S ) h a s a t y p i c a l electrocardiographic pattern characterized by increased propensity for malignant ventricular arrhythmias and sudden death in patients with no structural heart disease.1 Brugada phenocopies (BrP) have electrocardiographic patterns that are identical to true type 1 and type 2 Br, despite the absence of a true congenital BrS. BrP are elicited by clinical conditions including ionic (or water and electrolyte) disturbances, myocardial ischemia and pulmonary embolism.2-5 We report a case of suicide attempt by an overdose of propafenone which yielded a type 1 Brugada pattern.

Low-frequency noise effects on the rat parotid gland: A transmission electron microscopy study

ABSTRACT Introduction: Low-frequency noise (LFN) is a ubiquitous physical stressor known to cause degenerative cellular changes and organ alterations with functional repercussions both in humans and animals. Materials and methods: After acceptance of the study protocol by a local ethics committee, 20 Wistar rats were randomly divided into two equal groups. One group was kept in silence and the other continuously exposed to LFN during 13 weeks. The rats had unlimited access to water and were fed standard rat chow. After exposure, the animals were sacrificed and the parotid glands were excised and prepared for transmission electron microscopy. Results: The acinar cells showed marked ultrastructural alterations, such as intracellular vacuolization, loss of cell polarity, increased heterochromatin, cytoplasmic inclusions, and oncocytic transformation. Conclusions: LFN induces ultrastructural changes in the rat parotid gland that correlate with previously described functional changes.

Human ex vivo dentin-pulp complex preservation in a full crown model

OBJECTIVES Currently, there is lack of human in vitro full tooth models that hold the odontoblast layer with pulp tissue in their native environment. The appearance of new in vitro and in vivo models has provided new understanding of the potential of tissue engineering in dental pulp regeneration. However, the development of new in vitro full tooth models will allow us to get closer to in vivo conditions. Thus, the aim of this study is to preserve a living dentin-pulp complex, in a novel in vitro full crown model, after tooth extraction. METHODS Twenty intact third molars, after preparation, were divided into four groups, with five samples each. We placed the negative control samples (C) in saline, and the tested groups were placed (T) in supplemented DMEM, at two different times: 1 and 7 days. The specimens were processed for light microscopy observation. RESULTS Contrary to C-groups, T-groups showed a functional dentin-pulp complex. The treated dentin-pulp complex presents normal histological appearance. CONCLUSIONS This study showed that it is possible to preserve a living dentin-pulp complex after tooth extraction during 7 days.

Flutter auricular atípico tardio após ablação de fibrilhação auricular

Cardiac surgery for structural heart disease (often involving the left atrium) and radiofrequency catheter ablation of atrial fibrillation have led to an increased incidence of regular atrial tachycardias, often presenting as atypical flutters. This type of flutter is particularly common after pulmonary vein isolation, especially after extensive atrial ablation including linear lesions and/or defragmentation. The authors describe the case of a 51-year-old man, with no relevant medical history, referred for a cardiology consultation in 2009 for paroxysmal atrial fibrillation. After failure of antiarrhythmic therapy, he underwent catheter ablation, with criteria of acute success. Three years later he again suffered palpitations and atypical atrial flutter was documented. The electrophysiology study confirmed the diagnosis of atypical left flutter and reappearance of electrical activity in the right inferior pulmonary vein. This vein was again ablated successfully and there has been no arrhythmia recurrence to date. In an era of frequent catheter ablation it is essential to understand the mechanism of this arrhythmia and to recognize such atypical flutters.

Industrial Noise and Tooth Wear - Experimental Study

Tooth wear is a complex multifactorial process that involves the loss of hard dental tissue. Parafunctional habits have been mentioned as a self-destructive process caused by stress, which results in hyperactivity of masticatory muscles. Stress manifests itself through teeth grinding, leading to progressive teeth wear. The effects of continuous exposure to industrial noise, a “stressor” agent, cannot be ignored and its effects on the teeth must be evaluated. Aims: The aim of this study was to ascertain the effects of industrial noise on dental wear over time, by identifying and quantifying crown area loss. Material and Methods: 39 Wistar rats were used. Thirty rats were divided in 3 experimental groups of 10 animals each. Animals were exposed to industrial noise, rich in LFN components, for 1, 4 and 7 months, with an average weekly exposure of 40 hours (8h/day, 5 days/week with the weekends in silence). The remaining 9 animals were kept in silence. The areas of the three main cusps of the molars were measured under light microscopy. Statistical analysis used: A two-way ANOVA model was applied at significance level of 5%. Results: The average area of the molar cusps was significantly different between exposed and non-exposed animals. The most remarkable differences occurred between month 1 and 4. The total crown loss from month 1 to month 7 was 17.3% in the control group, and 46.5% in the exposed group, and the differences between these variations were significant (p<0.001). Conclusions: Our data suggest that industrial noise is an important factor in the pathogenesis of tooth wear.