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Biomedical subjects

S Zucoloto

Publications and source records attributed to S Zucoloto.

At least 55 records · Page 3Linked to original sources
PubMed1992

Hepatic morphology changes after hepatic artery ligation in extrahepatic cholestasis.

The present study was performed to correlate changes in hepatic morphology with hepatic artery ligation (HAL) in the presence of extrahepatic cholestasis (EHC). The study was conducted on 36 male Wistar rats weighing 350 to 400 g, divided at random into four groups of 9 animals each: group I, sham operation (control); group II, HAL; group III, bile duct ligation (BDL); group IV, HAL plus BDL. After seven days, liver fragments were obtained for morphological study. The relative volume of the bile ducts was I > II < III and III > IV (P < 0.05). These data indicate that arterial irrigation is important for the nutrition of the biliary tree. Seventy-six percent of the animals submitted to HAL plus BDL showed hepatic necrosis. In general, the liver probably becomes more dependent on HA flow in the presence of EHC.

Animals↗
PubMed1991

Morphometric investigations of the colon mucosa in chronic Trypanosoma cruzi infected rats.

The objective of this investigation was to study the morphometry of the epithelial mucosa in the chronic phase of T. cruzi infection. Nine young female Wistar rats were inoculated with T. cruzi. Ten months after inoculation the animals were sacrificed and the proximal colon was collected for morphometric measurements of the thickness of the muscle layers, the number of neurons in the myenteric plexus, the crypt cell population (CCP), crypt cell production per crypt (CCPC) and turnover time (TT) of the epithelium. There was no muscle layer hypertrophy but there was significant denervation in the group inoculated with T. cruzi, which also showed hyperplasia of the epithelium. The data suggest that denervation of the myenteric plexus did not induce hypertrophy of the propria muscle layer itself but altered the morphometry of the colonic epithelium in T. cruzi-infected animals, with increased development of CCP and TT. It is possible that this epithelial hyperplasia, as a consequence of a longer crypt cell TT, increased the absorption and secretion activities of the colon, which in turn may participate in the genesis of the enteromegalies observed in the chronic phase of Chagas' Disease.

Animals↗
PubMed1991

The chronological relationship between the thickening of smooth muscle, epithelial cell proliferation and myenteric neural denervation in the rat jejunum.

The jejunum of rats was treated by serosal application of a 0.2% solution of benzalkonium chloride (BAC) for 30 min. Control animals were treated with saline (0.9% NaC1). The animals were allocated to eight groups of 10 rats each and sacrificed 15, 30, 45, 60 days after BAC treatment. Segments were removed from the jejunum for neuronal counting, measurement of the smooth muscle area and morphokinetic study of the epithelium. There was a significant reduction in neuron number in the myenteric plexus 30 days after BAC treatment, thickening of smooth muscle 15-60 days after BAC treatment, but no change in epithelial cell proliferation in the jejunum at either time.

Animals↗
PubMed1991

Experimental paracoccidioidomycosis in ethyl alcohol-fed rats.

1. The course of experimental paracoccidioidomycosis was studied in alcohol-fed rats and compared with pair-fed and ad libitum controls. The alcohol-fed rats were fed a regular commercial solid diet plus a 32% (v/v) ethyl alcohol-25% sucrose (w/v) solution 4 weeks prior to the infection and throughout the study. The inoculum was standardized in terms of virulence, age of culture, percentage of multicellular fungal units containing 1-3 cells and viability. 2. The extent of infection was measured by quantitative counts of fungal units (FU), colony-forming units (CFU) of Paracoccidioides brasiliensis from infected pulmonary tissue and histopathological examination of the main organs involved. The specific humoral response and cell-mediated immunity of the animals were assessed by measuring the specific serum antibody levels by counterimmunoelectrophoresis (CIE) and by the footpad swelling test (FST), respectively. 3. Alcohol-fed rats and pair-fed controls did not differ significantly in mean body weight or the extent of disease after 5 and 10 weeks of infection. In contrast, the alcohol-fed group when compared with the ad libitum group presented a significantly lower mean body weight (301.6 +/- 0.6 vs 389.6 +/- 0.7 g) and a larger number of fungi recovered from the lung: 81.1 +/- 4.1 x 10(4) vs 13.4 +/- 8.0 x 10(4) FU; 24.3 +/- 8.6 x 10(4) vs 2.9 +/- 0.5 x 10(4) CFU after 5 weeks of infection. There were no significant differences in the specific antibody levels, FST indices, histopathological pattern of frequency of disseminated lesions between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcoholism↗
PubMed1991

Effect of oral phytohaemagglutinin intake on cell adaptation in the epithelium of the small intestine of the rat.

The effect of phytohaemagglutinin (PHA) on the adaptation of the proximal jejunal epithelium and on the distal ileal epithelium was studied in rats. The group receiving PHA gained less weight than controls, and the enterocyte population of their jejunal villi, as well as the morphokinetic parameters (length, population, crypt cell production per crypt) of their jejunal and ileal crypts were higher than those of the controls. The proximal lesion caused by PHA (reduction of villus cell populations) stimulates hyperplasia of the crypt-villus unit of the ileal epithelium with the development of adaptation from afar. These adaptations occurred in animals that ingested PHA even in the presence of severe malnutrition.

Administration, Oral↗
PubMed1990

Mucosal alterations in human chronic chagasic esophagopathy.

Patients diagnosed as having chronic chagasic esophagopathy were divided into three groups on the basis of radiologic findings: group I, no dilation; group II, moderate dilation, and group III, extensive dilation. Stasis esophagitis was more frequent in group III, with a significant increase in basal layer thickness when compared with groups I and II. The pathogenesis of basal layer hyperplasia may have been due to stasis of ingested food and to myenteric denervation of the viscera. This hyperplasia may be an intermediate condition explaining the higher frequency of cancer among patients with chagasic megaesophagus.

Biopsy↗
PubMed1990

Hepatic regeneration after hepatectomy in schistosomatic fibrosis.

After partial hepatectomy (approximately 30%), the labelled hepatocyte index (LHI) of the normal mouse is increased and reaches its highest value 48 h after surgery. In mice with schistosomatic fibrosis (SF), the LHI was lower than in the controls at 24, 48 and 72 h after hepatectomy.

Animals↗
PubMed1989

Effect of the intake of an exclusive sucrose diet on acetaminophen hepatotoxicity in rats.

1. To test the effect of a sucrose diet on acetaminophen hepatotoxicity, 20 male Wistar rats were fasted and 20 were maintained exclusively on a sucrose diet ad libitum for 66 h. After 42 h, acetaminophen (1 g/kg) was administered through an orogastric tube to 10 fasted animals and to 10 animals on the sucrose diet, or intraperitoneally to the remaining animals. Animals were killed 24 h later and blood was collected for the measurement of alanine and aspartate aminotransferase activity and the liver was removed for macroscopic and microscopic examination. 2. Plasma alanine and aspartate aminotransferase levels were significantly lower (P less than 0.001) in all animals maintained on the sucrose diet. Macroscopic examination revealed parenchymatous necrosis in 90% (18/20) of the fasted animals but in none of the animals fed sucrose. Microscopic examination confirmed the macroscopic findings and permitted the detection of liver necrosis in one additional fasted animal. 3. We conclude that ingestion of a sucrose diet protected the animals from the hepatotoxic effects of acetaminophen regardless of the route of administration of the drug.

Acetaminophen↗
PubMed1988

Effect of chemical ablation of myenteric neurones on intestinal cell proliferation.

The duodenum or descending colon of male Wistar rats (average weight 60 g) was treated by a serosal application of a 0.2% solution of benzalkonium chloride (BAC) for 30 min. Control animals were treated with 0.9% (physiological) saline. The rats were allocated to four groups: Group DC (N = 8) in which the duodenum was treated with physiological saline; Group DB (N = 8) in which the duodenum was treated with BAC; Group CC (N = 7) in which the descending colon was treated with physiological saline and Group CB (N = 7) in which the descending colon was treated with BAC. After treatment, the animals were followed up for 5 months. At the end of the experiment, the animals were injected intraperitoneally with vincristine sulphate before sacrifice. Three segments were removed from the duodenum and descending colon for neuronal counting, catecholamine and serotonin measurements and morphokinetic studies of the epithelium. The following results were obtained: (1) there was a significant reduction in neurone number in the myenteric plexus of segments treated with BAC; (2) in the denervated intestinal segments, catecholamine levels were unchanged whereas serotonin levels were increased; (3) epithelial hyperplasia was observed in the denervated duodenum and descending colon; and (4) crypt cell production rate in the duodenum was similar in groups DC and DB but was significantly increased in the descending colon in group CB as compared with controls (CC). The present findings indicate that selective myenteric neuronal denervation caused by benzalkonium chloride plays a causative role in the hyperplasia and crypt cell production rate of the intestinal epithelium (duodenum and descending colon). These changes are probably induced by functional imbalance by the surviving neuronal elements in the gut, implicating neurotransmitters such as acetylcholine, noradrenaline, serotonin, somatostatin and vasoactive intestinal peptide.

Animals↗
PubMed1988

Acute and subacute effects of thiamine deficiency on the morphometry and cell kinetics of jejunal and ileal epithelial cells.

The effects of acute and subacute thiamine deficiency on jejunal and ileal epithelial cells were studied in rats, using crypt and villus cell population, crypt cell production per crypt (CCPC), crypt growth fraction (Ip) and crypt cell cycle time (Tc) as parameters. In acute thiamine deficiency there was marked jejunal hypoplasia of the crypt and villus, but in the ileum there was hypoplasia only of the crypt. The jejunal epithelium of the subacute thiamine deficiency (STD) group showed no morphometric changes. In contrast, in the ileal epithelium of STD rats there was decreased crypt depth and villus cell population. Thiamine deficiency had no significant effect on CCPC, Ip and Tc.

Animals↗
PubMed1988

Immunohistochemical identification of lysozyme and vimentin in an experimental malignant fibrous histiocytoma.

The immunoperoxidase avidin-biotin-peroxidase complex method was used to investigate the presence of histiocyte markers such as lysozyme, alpha-1-antitrypsin (A1AT) and alpha-1-anti-chymotrypsin (A1ACT) and of vimentin, a specific marker for mesenchymal differentiation, in a spontaneous and transplantable rat tumor of supposed fibroblastic-histiocytic origin. Positive staining was obtained for lysozyme and vimentin but A1AT and A1ACT were not demonstrable in any of the tumor sections. These results provide evidence for the fibro-histiocytic nature of the tumor studied and suggest its classification as a malignant fibrous histiocytoma (MFH).

Animals↗
PubMed1987

Acute thiamin deficiency: a morphometric and cell proliferation study of jejunum epithelial cell.

The effect of acute thiamin deficiency on the jejunum epithelial cell was investigated in rats. The following results were obtained: The animals in the thiamin deficiency group (ATD) started to show a significant body weight loss from the 17th day in relation to pair fed controls (PFC). The length of the villus, depth and the cell population of the crypt from ATD animals were significantly decreased as compared to PFC. Crypt cell production rate (CCPR) was similar in both groups. However, even with epithelial hypoplasia, CCPR was maintained in thiamin-deficient animal, probably due to the presence of immature villus cells, which may reduced chalone and thus cause crypt to be more proliferative.

Animals↗
PubMed1985

Chronic effects of alcohol on the epithelium of the small intestine using two experimental models.

The effects of chronic alcohol ingestion on the rat small intestinal epithelium have been measured using two different experimental models, viz. either a solid diet plus alcohol or a liquid diet plus alcohol. All experimental animals consumed adequate quantities of food and exhibited a normal growth rate; thus the recorded effects were unlikely to be associated with malnutrition. After a period of 24 days, there were significant decreases in the jejunal villus cell population in both groups of experimental animals and corresponding increases in the crypt cell populations; no such changes were found in the ileum. Alcohol had no significant effect on the crypt cell production rate and the growth fraction at either of these two sites in the intestine, and thus the major effect of alcohol was to cause a lengthening of the cell cycle time in the jejunal crypts.

Alcoholism↗
PubMed1985

Acute gluten challenge in treated adult coeliac disease: a morphometric and enzymatic study.

Using a Quinton hydraulic biopsy tube, jejunal biopsies were obtained from 10 patients with adult coeliac disease in remission and four healthy volunteers before and after administration of gluten fraction III into the proximal duodenum. The biopsies taken at hourly intervals for four hours, were analysed for changes in brush border enzymes, light microscopic appearances, and villous and crypt population counts. The results indicate that mucosal damage occurs within three to four hours of gluten administration with significant falls in brush border enzyme concentrations and villous population counts. The absence of any change in control biopsies indicates that gluten sensitivity is specific to the mucosa of patients with coeliac disease, the timing of the changes being consistent with a type III immune response or direct toxicity. Some recovery of the brush border enzymes but not the villous population was evident 24 hours after gluten administration while the crypt population showed evidence of a compensatory hyperplastic reaction.

Adult↗
PubMed1984

Experimental models of chronic alcoholism, solid diet versus liquid diet.

The liquid diet and solid diet experimental models of chronic alcoholism were compared. The intake of food and the growth of rats were recorded for 24 days. All the alcoholic animals receiving either liquid or solid diet consumed adequate amounts of protein, fat, carbohydrate, salts and vitamins, and showed normal development. However the alcoholic animals given solid diet consumed more calories (total), more calories as alcohol and showed early adaptation to the diet in comparison to alcoholic animals that received the liquid diet.

Alcoholism↗
PubMed1982

Ultrastructural changes in nutritional cardiomyopathy of protein-calorie malnourished rats.

In this investigation, the ultrastructural features of the nutritional cardiomyopathy of protein-calorie-malnourished rats were examined. Protein-calorie malnutrition was induced in young rats by feeding them a low-protein diet (4% protein) for 6 weeks. Control animals were fed a high-protein diet (16% protein). The deficient rats showed severe restriction of body-weight gain, fatty liver and hypoproteinaemia. The results of the present study clearly demonstrated that the experimentally induced protein-calorie malnutrition brings about striking morphological changes in the heart of the rat. On light microscopy hyalinization an vacuolization of muscle fibres, loss of cross striations and myofibrils, small foci of necrosis, interstitial fibrosis and mononuclear-cell infiltration could be detected. The ultrastructural lesions were characterized by myofibrillar degeneration, contraction-band formation, dilatation of sarcoplasmic reticulum, mitochondrial swelling, dehiscence of intercalated discs, and widened interstitial spaces, especially around vessels, due to oedema fluid and cellular infiltration by mononuclear cells an activated fibroblasts with collagen fibres and microfibrils. In addition, an increase in relative heart weight was also observed. The potential role of catecholamines in the pathogenesis of this cardiomyopathy is discussed.

Animals↗