Emanuel Monteiro

Liver enzymes and ultrastructure in rabbit haemorrhagic disease (RHD)

Rabbit haemorrhagic disease (RHD) is caused by a calicivirus infection that kills most adult rabbits 24–72 h after viral inoculation. Two liver enzymes (AST, aspartate aminotransferase, and ALT, alanine aminotransferase) were monitored in blood samples of calicivirus-infected rabbits during the short course of RHD. Values of AST were used to differentiate three stages of hepatocellular degeneration in RHD: mild (up to 20-fold increase in AST), moderate (150–200-fold elevation of AST) and severe (more than 1000-fold elevation in AST). Liver samples of rabbits from these three biochemical stages of hepatocellular degeneration of RHD were studied by transmission electron microscopy to define the fine structure of the hepatocytes. In the mild hepatocellular degeneration there was proliferation (microvesiculation) of the smooth endoplasmic reticulum and swelling of mitochondria into spheroid bodies with loss of cristae. In moderate hepatocellular degeneration, vacuolization of cytoplasm and mitochondrial damage continued to be present, and there was also formation of autophagic vesicles. In the severe hepatocellular degeneration of RHD, the altered mitochondria also showed loss of density of their matrix; rupture of cytoplasmic vacuoles led to the formation of large vesicles. Marked depletion of liver glycogen was also found in this late stage of RHD. These data offer a correlation between biochemical and cytological features of the liver during the hepatocellular degeneration of RHD.

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.

Fine structure of Chloromyxum menticirrhi n. sp. (Myxozoa) infecting the urinary bladder of the marine teleost Menticirrhus americanus (Sciaenidae) in Southern Brazil.

A myxosporidian was found in the urinary bladder of the teleost Menticirrhus americanus Linnaeus, 1758 (Sciaenidae) collected from the South Atlantic coast of Brazil. Polysporic amoeboid plasmodia containing sporoblasts, developing pansporoblasts and spores were free in the bladder lumen. The prevalence of infection was 17.64% (15/85). Unfixed spores were spherical to subspherical, on average 10.5microm long, 9.8microm wide and 10.1microm thick (n=25), and fixed spores measured 10.1 x 9.5 x 9.7microm. The two spore valves were of equal size and each possessed prominent sutural lines and about 41 (37-45) surface ridges aligned parallel with the suture line. These ridges gave transverse sections a cog-wheel-like outline. The spores contained four pyriform polar capsules of equal size (3.20 x 2.0microm) (n=25) (fixed), each with a polar filament having 3-4 (rarely 5) coils. The binucleate sporoplasm was irregular in shape, with granular matrix and randomly distributed dense bodies. The shape and dimensions of the spore, as well as the number, position and arrangement of the surface ridges, polar capsules and polar filament indicate that this is a new species, herein designated Chloromyxum menticirrhi. The gill, liver, gall bladder and intestine of the host showed no abnormalities.

Involvement of central airways in vibroacoustic disease patients.

INTRODUCTION Vibroacoustic disease (VAD) is the whole-body pathology caused by excessive exposure to LFN. For the past 25 years, it has been know that low frequency noise (LFN, < 500 Hz, including infrasound) targets the respiratory system. In LFN-exposed rodents, the morphological changes of respiratory tract tissue partially explained some respiratory symptoms reported by VAD patients. However, many questions remain unanswered. Recently, some volunteer VAD patients underwent bronchoscopy in order to ascertain possible damage that could be associated with their respiratory complaints. METHODS Fourteen fully-informed and volunteer VAD patients were submitted to bronchoscopy, and biopsies were removed for analysis. RESULTS All patients exhibited small submucosal vascular-like lesions near the spurs, consisting of increased collagen and elastin fibres. Histology disclosed cilliary abnormalities, basal membrane hyperplasia, and thickening of vessel walls. In five patients, collagen bundles appeared degenerative and disrupted. No inflammatory process was ever identified, and no differences were seen between smokers and non-smokers. DISCUSSION Data is in accordance with what was observed in LFN-exposed animal models and also in 8 VAD patients who developed lung tumours. Collagen disruption and degeneration was also observed in electron microscopy images of the respiratory tract of LFN-exposed rodents. Thickened blood and lymphatic vessel walls have been consistently seen in images of VAD patients and of LFN-exposed rodents. During bronchoscopy performed by other reasons, this sort of structural aspects is not frequently seen. Taken together, it is strongly suggested that these findings could be VAD-specific.

O epitélio respiratório em ratos Wistar

Morphofunctional changes of respiratory epithelia became the object of intense study in Wistar rats after previous research showed that occupationally-simulated exposure to low frequency noise (≤ 500 Hz, including infrasound) induced irreversible lesions in these tissues. Aspects of normal respiratory epithelia in rats are lacking in the literature, and are the object of this report. Ten Wistar rats were kept in silence, fed standard rat food, and had unrestrained access to water (treated in accordance with 86/609/CE). The animals were sacrificed at 3.5 months of age, and respiratory epithelial fragments were excised and prepared for scanning (SEM) and transmission (TEM) electron microscopy. Brush cells (BC) were frequently observed with TEM, but with SEM they were often covered by the cilia of neighbouring cells. BC were always observed at the center of a ring of secretory cells (SC), in a rosetta-shaped formation. In TEM, the microvilli of SC surrounding the BC were uniform, and had the same density and shape in all cells. Multivesicular bodies were identified in areas within the BC. Formation and budding of vesicles from ciliary plasma membranes and from BC microvilli were frequently observed in both TEM and SEM. These data contribute to the understanding of the BC function. REV PORT PNEUMOL 2003; IX (5): 381-388

Participação das vias aéreas centrais na doença vibroacústica

Introduction. Vibroacoustic disease (VAD) is the whole-body pathology caused by excessive exposure to LFN. For the past 25 years, it has been know that low frequency noise (LFN, < 500 Hz, including infrasound) targets the respiratory system. In LFN-exposed rodents, the morphological changes of respiratory tract tissue partially explained some respiratory symptoms reported by VAD patients. However, many questions remain unanswered. Recently, some volunteer VAD patients underwent bronchoscopy in order to ascertain possible damage that could be associated with their respiratory complaints. Methods. Fourteen fully-informed and volunteer VAD patients were submitted to bronchoscopy, and biopsies were removed for analysis. Results. All patients exhibited small submucosal vascular-like lesions near the spurs, consisting of increased collagen and elastin fibres. Histology disclosed cilliary abnormalities, basal membrane hyperplasia, and thickening of vessel walls. In five patients, collagen bundles appeared degenerative and disrupted. No inflammatory process was ever identified, and no differences were seen between smokers and non-smo-kers. Discussion. Data is in accordance with what was observed in LFN-exposed animal models and also in 8 VAD patients who developed lung tumours. Collagen disruption and degeneration was also observed in electron microscopy images of the respiratory tract of LFN-exposed rodents. Thickened blood and lymphatic vessel walls have been consistently seen in images of VAD patients and of LFN-exposed rodents. During bronchoscopy performed by other reasons, this sort of structural aspects is not frequently seen. Taken together, it is strongly suggested that these findings could be VAD-specific. Rev Port Pneumol 2006; XII (2): 93-105

O epitélio respiratório em ratos Wistar após 48 horas de exposição contínua ao ruído de baixa frequência

RESUMO Em estudos anteriores, demonstrou-se que a exposicao cronica de ratos Wistar a ruido de baixa frequencia (RBF) provoca o estabelecimento de lesoes definitivas no epitelio respiratorio. A existencia de possiveis periodos refractarios tornou-se materia de grande interesse. Neste estudo avaliam-se as alteracoes do epitelio respiratorio de ratos Wistar apos uma exposicao continua a RBF. Doze ratos foram expostos a RBF continuo durante 48 horas. Dez ratos de controlo, do mesmo grupo etario, foram mantidos nas mesmas condicoes mas em silencio. Os animais foram tratados de acordo com a norma 86/609/ /CE. Apos a exposicao, 2 ratos foram imediatamente sacrificados e grupos de 2 foram sucessivamente sacrificados, respectivamente, apos 6, 12, 24, e 48 horas e sete dias em silencio. Fragmentos do epitelio respiratorio foram processados para microscopia optica electronica de varrimento. Seis horas apos o termo da exposicao, era visivel tumefacao intensa e irregular das celulas e eram evidentes estruturas em roseta contendo celulas em escova rodeadas por celulas secretoras. Os cilios apresentavam-se alterados e as microvilosidades das celulas em escova estavam agrupadas e perdiam a distribuicao uniforme tipica e observada nos animais de controlo. Estes aspectos observavam-se nas horas seguintes, embora diminuindo gradualmente de intensidade. Sete dias apos o termo da exposicao, tanto os ratos de controlo como os ratos expostos e mantidos em silencio apresentavam epitelios com caracteristicas nao distinguiveis. As lesoes epiteliais do aparelho respiratorio provocadas pela exposicao ao RBF sao reversiveis se forem respeitados periodos de recuperacao. REV PORT PNEUMOL 2003; IX (6): 473-479

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.