Histomorphological evaluation of acellularized bovine pericardium in breast implant coverage.

Bovine pericardium (BP) has been used as a biomaterial for several decades in many medical applications particularly due to its mechanical properties and the high collagen content. In the acellular form it favors faster tissue repair, providing a three-dimensional support for cellular and vascular events observed during tissue repair and due, to a low elastin content, may favor its use as a breast implant cover, resulting in a low possibility of contracture of the biomaterial, preventing the appearance of irregularities during the reconstruction process. Thus, the aim of this study was to evaluate, histomorphologically, the behavior of acellularized bovine pericardium (ABP) as a mammary implant cover in rats. For this purpose, 16 animals were divided into two groups, with eight animals at each biological point: 7 and 15 days after surgery. Of the 16 animals, 32 specimens were obtained: 16 in the experimental group (EG) and 16 in the control group (CG). Throughout this study, none of the studied groups had postoperative complications. Results: The histomorphological results showed, in the two biological points, both in the EG and in the CG, chronic inflammatory infiltrate, leukocyte fibrin exudate, formation of granulation tissue and deposition of collagen fibers, more evident in the EG, regressive along the biological points. At 15 days, the implanted ABP showed initial biointegration with the fibrous capsule and surrounding tissues of the recipient bed. Conclusion: These results indicate that the due to the observed favorable tissue response ABP may be of potential use as a breast implant cover.

Decreased humoral and pathologic responses in undernourished mice infected with Schistosoma mansoni.

We previously demonstrated that mice subjected to a hypoproteinic diet showed milder chronic lesions on infection with Schistosoma mansoni than normally fed mice. Here we compare the immune response of well-nourished and undernourished mice with chronic S. mansoni infection. The proliferative response and cytokine (IFN-gamma and IL-5) production of splenocytes from undernourished mice against the soluble egg antigen (SEA) of S. mansoni or concanavalin A was similar to that of well-nourished mice. The levels of SEA-specific IgG1, IgG2b and IgG3 antibodies were significantly higher in the sera of well-nourished mice in comparison with undernourished mice. Undernourished animals also exhibited diminished periovular granuloma size compared to well-nourished infected controls. Our results support the importance of host nutritional status in the humoral immune response of mice and its effects on the development of periovular granulomas in malnourished animals infected with S. mansoni.

B-cell infiltration and frequency of cytokine producing cells differ between localized and disseminated human cutaneous leishmaniases

Biopsies from human localized cutaneous lesions (LCL n = 7) or disseminated lesions (DL n = 8) cases were characterized according to cellular infiltration,frequency of cytokine (IFN-g, TNF-alpha) or iNOS enzyme producing cells. LCL, the most usual form of the disease with usually one or two lesions, exhibits extensive tissue damage. DL is a rare form with widespread lesions throughout the body; exhibiting poor parasite containment but less tissue damage. We demonstrated that LCL lesions exhibit higher frequency of B lymphocytes and a higher intensity of IFN-gamma expression. In both forms of the disease CD8+ were found in higher frequency than CD4+ T cells. Frequency of TNF-alpha and iNOS producing cells, as well as the frequency of CD68+ macrophages, did not differ between LCL and DL. Our findings reinforce the link between an efficient control of parasite and tissue damage, implicating higher frequency of IFN-gamma producing cells, as well as its possible counteraction by infiltrated B cells and hence possible humoral immune response in situ

Hepatic capillariasis in rats: a new model for testing antifibrotic drugs

Rats infected with the helminth Capillaria hepatica regularly develop septal hepatic fibrosis that may progress to cirrhosis in a relatively short time. Because of such characteristics, this experimental model was selected for testing drugs exhibiting antifibrosis potential, such as pentoxifylline, gadolinium chloride and vitamin A. Hepatic fibrosis was qualitatively and quantitatively evaluated in liver samples obtained by partial hepatectomy and at autopsy. The material was submitted to histological, biochemical and morphometric methods. A statistically significant reduction of fibrosis was obtained with pentoxifylline when administered intraperitoneally rather than intravenously. Gadolinium chloride showed moderate activity when administered prophylactically (before fibrosis had started), but showed a poor effect when fibrosis was well advanced. No modification of fibrosis was seen after vitamin A administration. Hydroxyproline content was correlated with morphometric measurements. The model appears to be adequate, since few animals die of the infection, fibrosis develops regularly in all animals, and the effects of different antifibrotic drugs and administration protocols can be easily detected

Pathogenesis of schistosomal 'pipestem' fibrosis: a low-protein diet inhibits the development of 'pipestem' fibrosis in mice.

Mice maintained on a low protein diet for 30 days and then infected with Schistosoma mansoni for 16 weeks completely failed to develop 'pipestem fibrosis' of the liver, whereas 50% of well nourished controls did. Usually mice with relatively mild and prolonged S. mansoni infection develop two different pathological pictures: one consisting of disseminated portal fibrosis caused by periovular granulomas concentrated at the portal spaces (pipestem fibrosis), the other represented by scattered hepatic granulomas. The reason for this dual response is poorly understood. Combined results from parasitological, histopathological, biochemical and morphometric data revealed that peri-ovular granulomas of undernourished mice were smaller, inflammation was less intense and there was minimal fibrosis in comparison with those of controls, which suggest that a vigorous host response is necessary for the pathogenesis of schistosomal portal fibrosis.

[Hepatic viscerotomy (its contribution to the study of regional nosology)]. / Viscerotomia hepática (sua contribuição ao estudo da nosologia regional.

As a part of a routine yellow fever surveillance program going on in the south of Bahia State, Brazil, liver fragments were obtained through postmortem viscerotomy from 702 individuals who died after presenting acute febrile illness from 1981 up till 1991. Instead of being only screened for the presence of yellow fever, the liver tissue was thoroughly evaluated by histopathology. More than a third of the cases exhibited marked and diffuse steatosis occurring in malnourished infants and young children. Hepatic fibrosis, granulomatous disease compatible with disseminated tuberculosis, advanced schistosomiasis, chronic alcoholic injury, chronic hepatitis and cirrhosis were also frequently observed. A miscellaneous group of hepatic pathological processes were also recognized, which included such diverse entities as Hodgkin's disease, glycogenosis, sickle-cell disease, hepatocarcinoma, etc. Only 124 (17.7%) cases showed normal hepatic histology. The wide possibility of histological diagnoses strongly indicates that the material obtained by viscerotomy can be further explored by an interested pathologist, to help in the understanding of nosology and epidemiology, concerning remote geographic areas where viscerotomy is being routinely performed.

Experimental pulmonary schistosomiasis: lack of morphological evidence of modulation in schistosomal pulmonary granulomas.

Numerous pulmonary schistosome egg granulomas were present in mice submitted to partial portal vein ligation (Warren's model). The granulomas were characterized by cellular aggregations formed within alveolar tissue. Main cellular types were macrophages (epithelioid cells), eosinophils, plasma cells and lymphocytes. These cells were supported by scanty fibrous stroma and exhibited close membrane contact points amongst themselves, but without forming specialized adhesion apparatus. When granulomas involved arterial structures, proliferation of endothelial and smooth muscle cells occurred and fibrosis associated with angiogenesis became more evident. Granulomas formed around mature eggs in the pulmonary alveolar tissue presented approximately the same size and morphology regardless of the time of infection, the latter being 10, 18 and 25 weeks after cercarial exposure. This persistence of morphological appearance suggests that pulmonary granulomas do not undergo immunological modulation, as is the case with the granulomas in the liver and, to a lesser extent, in the intestines. Probably, besides general immunological factors, local (stromal) factors play an important role in schistosomal granuloma modulation.

Dynamics of fibrosis production and resorption in intestinal schistosomiasis of mice.

A histological, morphometric and immunocytochemical study of schistosomal periovular granulomas in the liver and intestines of mice revealed that intestinal granulomas are smaller and contain less collagen than those in the liver. After curative treatment intestinal granulomas undergo a relatively more rapid resorption, although the general pattern of collagen degradation apparently does not differ from that observed in the liver. Tendency to form scattered, usually isolated granulomas that are only mildly fibrogenic, coupled with a well-balanced process of resorption appear as the explanation why intestinal fibrosis is not an outstanding feature of schistosomiasis as it is in the liver.

The pathology of experimental visceral leishmaniasis in resistant and susceptible lines of inbred mice.

1. The main pathological features of experimental visceral leishmaniasis were characterized in resistant and susceptible inbred mouse strains. 2. Disseminated granulomas containing parasitized macrophages were found especially in the liver and spleen of two inbred mouse strains, i.e. the resistant DBA/2 and the susceptible C57BL/10 strains, which had been inoculated with Leishmania donovani chagasi amastigotes. 3. The lesions tended to remain granulomatous in nature even during the early acute phase of the more susceptible mouse strain (C57BL/10), and later evolved to a decrease in number of parasites and granulomas and in granuloma diameter. However, no healing occurred up to the end of the observation period of 70 weeks for the C57BL/10 strain. 4. Visceral leishmaniasis in the mouse model does not resemble the classical human Kala-azar, but seems to be more related to oligosymptomatic forms seen in humans living in endemic areas.

Pentastomiase em roedor no estado da Bahia. Nota sobre o encontro de Armillifer moniliformis (Diesing, 1835) Sambon, 1922. / Pentastomiasis in rodents in the State of Bahia. Report of the finding of Armillifer moniliformis (Diesing, 1835) Sambon, 1922)

Foi identificado em um roedor silvestre Zigodontomys pixuna Moojen, 1943), capturado no interior do Estado da Bahia, eyemplar de Armillifer moniliformis (Diesing, 1835) Sambon, 1922, um agente etiologico da pentastomiase humana na Asia. Este encontro se faz pela primeira vez na America

Identificacao do Trypanosoma cruzi nos tecidos extracardiacos de portadores de miocardite cronica chagasica. / Identification of Trypanosoma cruzi in extra cardiac tissues in patients with chronic Chagas' myocarditis

Em autopsias realizadas durante 20 anos em portadores de miocardite cronica chagasica parasitologicamente comprovados, foi realizada uma pesquisa exaustiva das formas tissulares do Trypanosoma cruzi nas seccoes histologicas de varios orgaos. Os parasitos intracelulares foram encontrados nos tecidos extracardiacos em 11 casos (55%), a saber: tubo digestivo (10 vezes), adrenal (6 vezes) e em varios outros orgaos (1 vez cada). A presenca dos parasitos se associava com discreta infiltracao mononuclear focal, mas, o mais das vezes, nao havia qualquer alteracao. O estudo mostra que as formas de multiplicacao do T. cruzi tendem a se distribuir amplamente na infeccao cronica, mas como sao escassos, o seu encontro depende de pesquisa minuciosa. Um fato interessante e que somente no miocardio os parasitos aparecem associados com inflamacao cronica, difusa, progressiva e fibrosante

Hepatite de Labrea em Salvador, BA? (Apresentacao de um possivel caso). / Labrea hepatitis in Salvador, BA? (Report of a possible case)

Um menino de quatro anos de idade, natural e residente em Salvador, Bahia, apresentou uma doenca febril, de curso rapido com febre, ictericia, dores abdominais, agitacao psicomotora, coma e morte no 7o. dia do internamento. Histologicamente o figado exibiu extensa necrose litica e de coagulacao dos hepatocitos, alem de degeneracao gordurosa aguda ("celulas em morula"), infiltracao mononuclear e colestase, um quadro considerado tipico da hepatite de Labrea. A existencia de tal caso levanta o problema da ocorrencia de hepatite de Labrea fora da Regiao Amazonica ou aquele de falta de especificidade do quadro histopatologico considerado como tipico da referida condicao