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Biomedical subjects

Z A Andrade

Publications and source records attributed to Z A Andrade.

At least 19 recordsLinked to original sources
PubMed1992

Hepatic connective tissue changes in hepatosplenic schistosomiasis.

Destruction of intrahepatic portal vein branches with dispersion of smooth muscle cells into the periportal fibrosis and preservation of arterial and ductal structures were the main characteristic findings seen in 66 surgical liver biopsies from patients with the hepatosplenic form of schistosomiasis. Besides these diagnostic features, the present histologic, immunocytochemical, and ultrastructural study revealed the presence of a complex matrix forming the portal and septal fibrosis in advanced schistosomiasis. There was marked hyperplasia of elastic tissue, presence of several collagen isotypes (I, III, procollagen III, IV, and V), actin, desmin, fibronectin, and laminin in a richly vascularized connective tissue. Signs of multifocal matrix (collagen) degradation were observed both at light and electron microscopic levels, suggesting a predominance of a fibrolytic process, at the time parasite-related lesions had almost disappeared. The latter findings are related to the involution of periportal fibrosis now being observed in patients who have undergone antischistosomal chemotherapy. They exemplify morphologic changes connected with chronic collagen degradation in human schistosomiasis that are similar to those first seen in experimental material. Evidence of either persistent or active chronic hepatitis was seen in several cases but its etiology could not be determined.

Adolescent↗
PubMed1992

Morphological aspects of early and late collagen degradation in granulation tissue.

A sequential histologic, ultrastructural and immuno pathologic study was carried out in the Selye's inflammatory pouch model to observe extracellular matrix and cellular changes during granulation tissue formation. Besides changes involving different components of the connective tissue, it was observed that collagen resorption occurred under a biphasic process. At an early phase (3rd to 15th day), in which exudative inflammatory changes predominated, signs of collagen synthesis and degradation were seen simultaneously. Extracellular breakdown and internalization of collagen fragments within fibroblasts and myofibroblasts were observed. Later on (30th to 60th day), changes affecting collagen had a different ultrastructural appearance. Collagen fragmentation, focal "lytic" and "electron dense" changes occurred in the extracellular space specially at the periphery of fibroblasts, myofibroblasts and smooth muscle cells. Collagen degradation, thus seems to be a continuous process in granulation tissue, occurring with different morphologies at different times.

Animals↗
PubMed1992

Morphological features of collagen degradation in advanced hepatic schistosomiasis of man.

Optical and electron microscopical evidences of focal matrix degradation were frequently seen in liver sections taken from patients with periportal ("pipe-stem") fibrosis caused by schistosomiasis mansoni. Besides the presence of focal areas of rarefaction, fragmentation and dispersion of collagen fibers, the enlarged portal spaces also showed hyperplasia of elastic tissue and disarray of smooth muscle fibers following the destruction of portal vein branches. Ultrastructural changes represented by focal lytic and/or electron dense alterations of collagen fibrils were similar to those first seen in experimental material and designated as "chronic collagen degradation". Elastin and related microfibrils were also affected by focal condensation, fragmentation, distortion and dissolution. Schistosome eggs were scanty in the tissue sections examined. Matrix degradation represented involuting changes related to the progressive diminution of parasite aggression, which occurs spontaneously with age or after cure by chemotherapy. Changes of focal matrix degradation now being described represent the basic morphological counterpart of periportal fibrosis involution documented clinically, especially by ultrasonography, in patients with hepatosplenic schistosomiasis submitted to curative chemotherapy.

Adolescent↗
PubMed1978

Histopathology of the conducting tissue of the heart in Chagas' myocarditis.

The conducting tissue of the heart was studied in 25 human cases of Chagas' myocarditis with a method which employs complete serial sections mounted on continuous transparent plastic tape. The pathological changes were correlated with electrocardiographic findings. The inflammation of the acute phase of Chagas' myocarditis, as seen in one single case, did not seem to interfere with conduction through the AV system. In chronic Chagas' myocarditis the conducting tissue showed extensive and variable changes: chronic inflammation, fibrosis, atrophy and fragmentation of specific fibers, extreme dilatation and tortuosity of veins, capillaries and lymphatics, fatty infiltration, and arterial medial and intimal fibrosis. A preferential involvement of the right bundle branch and the anterior fascicles of the left branch was observed and an excellent correlation with electrocardiographic abnormalities was found. There was also evidence presented that bundle branch block may be caused by disease proximal to the bundle branches. Complete AV block seemed to be the final result of the progressive inflammatory and degenerative changes involving the conduction system in chronic Chagas' myocarditis. Inflammation and fibrosis did also involve the sinoatrial node, Purkinje fibers, intracardiac nervous ganglia, and the contractile myocardium.

Acute Disease↗
PubMed1977

Hepatic artery hypertrophy and sinusoidal hypertension in advanced schistosomiasis.

In 5 patients with portal hypertension caused by schistosomiasis, the sinusoidal pressure (wedged hepatic pressure) varied from 20.7 to 35.4 mm Hg. While the catheter was in an occluded position within the hepatic vein and the patients were undergoing splenectomy, the main trunk of the hepatic artery was clamped. The sinusoidal pressures then fell to levels that varied from 3.7 to 7.4 mm Hg but returned to previous levels when the clamping was released. Wedged hepatic venous pressure levels, which were significantly greater than portal venous pressure values, decreased minimally after splenectomy. Portal venous pressure levels, however, fell to 63% of presplenectomy levels. In a control case with an enlarged spleen (cavernous hemangioma, but with a normal liver, the wedged hepatic pressure was 7.4 mm Hg and showed no alteration after clamping of hepatic artery. These data point out the importance of hepatic artery hypertrophy, that has already been demonstrated in other studies, in causing elevation of the wedged hepatic pressure in advanced hepatic schistosomiasis.

Adolescent↗
PubMed1976

Absence of schistosomal glomerulopathy in Schistosoma haematobium infection in man.

Kidneys were studied by light microscopy in 246 consecutive autopsies in Cairo, Egypt. Glomerulonephritis was not related to the presence or intensity of either S. haematobium or S. mansoni infection, and mesangial thickening and proliferation were also unrelated to schistosome infection. Acute and chronic pyelonephritis were also unrelated to the presence of schistosome infection.

Glomerulonephritis↗
PubMed1976

Hepatitis B surface antigen carrier state in hepatosplenic schistosomiasis.

The prevalence of hepatitis B surface antigen (HBsAg) was studied in 103 cases of hepatosplenic schistosomiasis (HSS), 134 control cases with a variety of illnesses including hepatointestinal schistosomiasis, and 600 blood donors, in an area endemic for both schisfosomiasis and viral hepatitis. The patients with HSS proved to be persistent carriers for HBsAg in a significantly higher proportion than the other two groups of cases. The HSS cases who were carriers of HBsAg had more clinical signs of chronic liver disease and strikingly more chronic inflammation of the portal spaces on liver biopsy. It is suggested that abnormal immunological responses in patients with HSS makes them more susceptible to become carriers of HBsAg and that the addition of this injurious factor makes their basic disease worse, and may be responsible for the development of cirrhosis in some cases.

Adult↗
PubMedDate not supplied

Pathology of periportal fibrosis involution in human schistosomiasis.

Optical and electron microscopical evidences of focal matrix degradation were frequently seen in liver sections of periportal fibrosis caused by schistosomiasis mansoni in man. The material came from 14 wedge hepatic biopsies taken from patients with chronic advanced hepatosplenic disease and undergoing operations for the relief of portal hypertension. Besides the presence of focal areas of rarefaction, fragmentation and dispersion of collagen fibers, the enlarged portal spaces also showed hyperplasia of elastic tissue and disarray of smooth muscle fibers following destruction of portal vein branches. Eggs were scanty in the tissue sections, and matrix degradation probably represented involuting changes related to the progressive diminution of parasite-related aggression, which occurs spontaneously with age or after cure by chemotherapy. The changes indicative of matrix degradation now described are probably the basic morphological counterpart of periportal fibrosis involution currently being documented by ultrasonography in hepatosplenic patients submitted to curative chemotherapy.

Adolescent↗
PubMedDate not supplied

Fulminant hepatitis with microvesicular steatosis (a histologic comparison of cases occurring in Brazil--Labrea hepatitis--and in central Africa--Bangui hepatitis).

A similar histopathologic picture of fatal hepatitis associated with widespread acute fatty changes in hepatocytes and single-cell necrosis was seen in epidemic cases occurring in two distinct equatorial areas having high prevalences of HBV and HDV infections. The cases were previously considered to be two different entities; Labrea hepatitis in Brazil, and Bangui hepatitis in the Central African Republic. However, the histopathologic findings suggest that they are pathogenetically and etiologically related to HBV and HDV infections, probably modified by some as yet unknown factor(s) present in equatorial forest zones.

Adolescent↗
PubMedDate not supplied

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.

Animals↗