Some unfavourable effects of malnutrition of the host on Schistosoma mansoni worm biology and structure have been reported based upon brigthfield microscopy. This paper aims to study by morphometric techniques, some morphological parameters in male and female adult worms recovered from undernourished albino mice in comparison with parasites recovered from well-fed infected mice. Undernourished animals were fed a multideficient and essentially low protein diet (RBD diet) and compared to well-fed control mice fed with the commercial diet NUVILAB. Seventy-five days post-infection with 80 cercarie (BL strain) animals were sacrificed. All adult worms were fixed in 10% formalin and stained with carmine chloride. One hundred male and 60 female specimens from each group (undernourished and control) were examined using an image system analysis Leica Quantimet 500C and the Sigma Scan Measurement System. The following morphometrical parameters were studied: body length and width, oral and ventral suckers, number and area of testicular lobes, length and width of ovary and uterine egg. For statistical analysis, the Student's t test for unpaired samples was applied. Significant differences (p < 0.05) were detected in body length and width, in parameters of suckers, uterine egg width, ovary length and area of testicular lobes, with lower values for specimens from undernourished mice. The nutritional status of the host has negative influence on S. mansoni adult worms, probably through unavailability of essential nutrients to the parasites.

Severe destruction of intrinsic cardiac nerves has been reported in experimental acute Chagas myocarditis, followed by extensive regeneration during the chronic phase of the infection. To further study this subject, the sympathetic and para-sympathetic intracardiac nerves of mice infected with a virulent Trypanosoma cruzi strain were analyzed, during acute and chronic infection, by means of histological, histochemical, morphometric and electron microscopic techniques. No evidences of destructive changes were apparent. Histochemical demonstration for acetylcholinesterase and catecholamines did not reveal differences in the amount and distribution of intracardiac nerves, in mice with acute and chronic Chagas myocarditis or in non-infected controls. Mild, probably reversible ultrastructural neural changes were occasionally present, especially during acute myocarditis. Intrinsic nerves appeared as the least involved cardiac structure during the course of experimental Chagas disease in mice.

O grau e a morfologia da degradação do colágeno foram comparativamente analisados em ratos com fibrose hepática recente (tratamento de oito semanas com tetracloreto de carbono) e tardia (igual tratamento por 12 semanas), e acompanhados após a suspensão da administração da droga. O desaparecimento da fibrose (quando quantitativamente avaliada) foi gradual e semelhante para ambos os grupos. As modificações vistas à microscopia de luz e ao microscópio eletrônico foram também semelhantes. Estes resultados inesperadamente negativos diferem de outros modelos de fibrose hepática e sugerem que o grau de agressão ao parênquima hepático seja um fator limitante da degradação da fibrose que se segue à remoção do agente causal. Assim sendo, não apenas a idade da fibrose, mas o estado geral de alteração do órgão atingido influenciam a degradação e remoção do colágeno.

The rate and morphology of collagen degradation were comparatively analyzed in rats with "early" and "late" carbon tetrachloride-induced hepatic fibrosis, during three different periods after discontinuation of the drug. Treatment with CCl4 lasted for eight weeks for the group of early fibrosis and 12 weeks for the late fibrosis group. Fibrosis gradually disappeared, but when quantitative methods were applied, the amount of collagen degradation and removal in early and late fibrosis did not reach statistical significance. The light microscope and ultrastructural changes were also qualitatively similar in both cases. Probably some long-lasting effects to the liver, induced by the drug, prevented early hepatic fibrosis from undergoing the characteristic ultrastructural changes seen during "acute" collagen degradation, as compared to other experimental models of hepatic fibrosis, after the causal agent is totally removed. Present findings suggest that not only the age of fibrosis but also the overall damage inflicted to the organ are limiting factors in the process of collagen degradation and removal.

Interferon-alpha is used in antiviral therapy in humans, mainly for viral hepatitis B and C. An anti-fibrotic effect of interferon has been postulated even in the absence of anti-viral response, which suggests that interferon directly inhibits fibrogenesis. Rats infected with the helminth Capillaria hepatica regularly develop diffuse septal fibrosis of the liver, which terminates in cirrhosis 40 days after inoculation. The aim of this study was to test the anti-fibrotic effect of interferon in this experimental model. Evaluation of fibrosis was made by three separate methods: semi-quantitative histology, computerized morphometry and hydroxyproline measurements. Treatment with interferon-alpha proved to inhibit the development of fibrosis in this model, especially when doses of 500,000 and 800,000 IU were used for 60 days. Besides confirming the anti-fibrotic potential of interferon-alpha on a non-viral new experimental model of hepatic fibrosis, a clear-cut dose-dependent effect was observed.

Histological, ultrastructural, morphometric and immunohistochemical data obtained from the study of spleens removed by splenectomy from 34 patients with advanced hepatosplenic schistosomiasis revealed that the main alterations were congestive dilatation of the venous sinuses and diffuse thickening of the splenic cords. Splenic cord thickening was due to an increase of its matrix components, especially type IV collagen and laminin, with the conspicuous absence of interstitial collagens, either of type I or type III. Deposition of interstitial collagens (types I and III) occurred in scattered, small focal areas of the red pulp, but in the outside of the walls of the venous sinuses, in lymph follicles, marginal zone, in the vicinity of fibrous trabeculae and in sidero-sclerotic nodules. However, fibrosis was not a prominent change in schistosomal splenomegaly and thus the designation "fibro-congestive splenomegaly" seems inadequate. Lymph follicles exhibited variable degrees of atrophy, hyperplasia and fibrous replacement, sometimes all of them seen in different follicles of the same spleen and even in the same examined section. Changes in white pulp did not seem to greatly contribute to increasing spleen size and weight, when compared to the much more significant red pulp enlargement.

Lesions involving the sympathetic (para-vertebral ganglia) and para-sympathetic ganglia of intestines (Auerbach plexus) and heart (right atrial ganglia) were comparatively analyzed in mice infected with either of three different strain types of Trypanosoma cruzi, during acute and chronic infection, in an attempt to understand the influence of parasite strain in causing autonomic nervous system pathology. Ganglionar involvement with neuronal destruction appeared related to inflammation, which most of the times extended from neighboring adipose and cardiac, smooth and striated muscular tissues. Intraganglionic parasitism was exceptional. Inflammation involving peripheral nervous tissue exhibited a focal character and its variability in the several groups examined appeared unpredictable. Although lesions were generally more severe with the Y strain, comparative qualitative study did not allow the conclusion, under the present experimental conditions, that one strain was more pathogenic to the autonomic nervous system than others. No special tropism of the parasites from any strain toward autonomic ganglia was disclosed.

Em camundongos submetidos à ligadura parcial da veia porta e infecção pelo Schistosoma mansoni, os granulomas periovulares apareceram em grande número nos pulmões, comprovando a validade do modelo de Warren. Histologicamente os granulomas eram representados por agregados celulares compactos no seio de escasso estroma. Os macrófagos (células epitelióides) e eosinófilos eram os elementos celulares predominantes, vindo em seguida os linfóticos e plasmócitos. Ultraestruturalmenle, as células do granuloma exibiam íntimo contacto de suas membranas, com varios pontos de adesão, mas sem formar estruturas juncionais mais específicas. Os granulomas formados em torno a ovos maduros tinham tamanho, forma e composição celular similares após 10, 18 ou 25 semanas de infecção. Este aspecto contrastava com o que aparecia nos granulomas hepáticos os quais exibiam a clássica modulação. Os granulomas que envolviam as paredes arteriolares exibiam proliferação muscular, endotelial, com formação de novas vias vasculares e fibrose. As diferenças morfológicas observadas nos granulomas formados em diferentes locais e órgãos apontam para a importância de se considerar fatores locais (estromais) no determinismo dos padrões das respostas inflamatórias.

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 cndothelial 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.