Nelson Fontana Margarido

Quantification by computerized morphometry of tissue levels of sulfomucins and sialomucins in diversion colitis in rats

PURPOSE To quantify the intensity of sulfomucin and sialomucin expression in the colon mucosa, by means of computer-assisted image processing, comparing segments with and without fecal stream and correlating with the duration of fecal transit exclusion. METHODS Forty-five Wistar rats were subjected to diversion of the fecal stream in the left colon by means of constructing a proximal colostomy and distal mucosal fistula. They were distributed randomly into three experimental groups of 15 animals, of which 10 were subjected to colon diversion (experimental subgroup) and five were only subjected to laparotomy, without colon diversion (control subgroup). The three experimental groups were formed according to the sacrifice date, which was to be performed six weeks after the surgical procedure (Group A), 12 weeks (Group B) and 18 weeks (Group C). The sulfomucin and sialomucin expression in the colon mucosa was evaluated using the histochemical technique of high iron diamine-alcian blue (HID-AB). The tissue expression was quantified for each animal, in the segments with and without fecal stream, at a location where there were four complete contiguous crypts in two random fields, with the aid of the computer-assisted image analysis software. The final value was taken to be the mean reading from the two fields selected, in the segments with and without fecal stream. To compare the expressions of the two mucin subtypes in the segments with and without fecal stream, the paired Student t test was used. To analyze variance according to duration of exclusion, ANOVA with the Newman-Keuls post-test was used, setting the significance level at 5% (p<0.05). RESULTS There were significant reductions in tissue sulfomucin and sialomucin content in the colon without fecal stream, independent of the duration of exclusion considered. There was increased tissue sulfomucin content and decreased tissue sialomucin in the segments without fecal stream, with increasing duration of exclusion. CONCLUSIONS Diversion of the fecal transit decreased the tissue sulfomucin and sialomucin content in the segments without fecal stream. Notwithstanding the reduction in the levels of both subtypes of acid mucin in the segments without fecal stream, there was increased tissue sulfomucin content and decreased tissue sialomucin with increasing duration of intestinal diversion.

Influência da irrigação de soluções nutricionais no colo excluso de trânsito intestinal: estudo experimental em ratos

Diversion colitis is described as an inflammatory process that occurs in the colorectal segments excluded of the fecal stream. The deficiency of the short-chain fatty acids inside of intestinal lumen was considered the main etiologic factor. AIM: The aim of the present study was valued, in experimental model of diversion colitis, the importance of the irrigation of the segment without fecal stream with nutritional solutions in prevention and treatment of the colic mucosa inflammation. METHOD: There were used thirty Wistar males rats, with initial weight varying between 350 and 500 grammas, submitted to the derivation of the fecal stream through proximal colostomy and distal mucous fistula. The animals were divided in three groups with 10 animals according to the irrigation of the excluded colic segment had been carried out with: SF Group: 0.9 % physiologic solution; GH Group: hypertonic glucose solution of 50 % and AG Group: solution of short-chain fatty acids. In all the animals, the irrigation of the excluded colon was carried each four days and the animals were sacrificed ever in 21st post-operative day. The removed fragments of the intestinal segments were colored by the techniques of hematoxylin-eosin and Masson trichromium. The histological variables studied were: thickness of the mucous layer, vascular congestion; inflammatory infiltrate and the level of tissue collagen. The considered results were subjected to statistical study considering signification level of 5 % (p <0.05). RESULTS: The obtained results showed that in the group where the excluded colon was irrigated with solution of short-chain fatty acids there was less vascular congestion, less inflammatory infiltrated and less collagen deposition when compared to another experimental groups. CONCLUSION: The results of the present study indicate that in the group receiving the short-chain fatty acid solution there was a decrease in the inflammatory infiltrate and the vascular congestion, as well as a reduction in the deposition of collagen tissue. The irrigation of segments without fecal stream with short-chain fatty acids it improves the inflammatory process found in the diversion colitis.

Reduction in oxidative stress levels in the colonic mucosa without fecal stream after the application of enemas containing aqueous Ilex paraguariensis extract

PURPOSE To evaluate the antioxidant effects of enemas containing aqueous extract of Ilex paraguariensis, comparing segments with and without fecal stream and correlating the segments with the duration of intervention. METHODS Twenty-six Wistar rats were subjected to a diversion of the fecal stream in the left colon by a proximal colostomy and distal mucosal fistula. The rats were distributed randomly into two experimental groups of 13 animals each based on the time of sacrifice after surgical procedure (two or four weeks). Each group was then divided into two experimental subgroups that received either second daily enemas containing 0.9% saline solution or aqueous extract of Ilex paraguariensis at 0.2g/100g. Colitis was diagnosed by histopathological analysis and the detection of oxidative tissue damage by measuring the levels of malondialdehyde. The Mann-Whitney test was used to compare the tissue levels of malondialdehyde between colon segments with and without fecal stream in each experimental group, and the Kruskal-Wallis test was used to verify the variance between the levels of oxidative stress according the duration of the irrigation; both tests determined significance at 5% (p<0.05). RESULTS The levels of malondialdehyde in the animals subjected to intervention in the colon with saline with and without fecal stream after two and four weeks of irrigation were 0.05±0.006 and 0.06±0.006, and 0.05± 0.03 and 0.08 ±0.02, respectively. The malondialdehyde levels in the animals irrigated with Ilex paraguariensis with and without fecal stream after two and four weeks of irrigation were 0.010±0.002 and 0.02±0.004, and 0.03±0.007 and 0.04±0.01, respectively. After two and four weeks of intervention, the levels of malondialdehyde were lower in the animals irrigated with Ilex paraguariensis regardless of the time of irrigation (p=0.0001 and p=0.002, respectively). CONCLUSION The daily rectal application of enemas containing aqueous extract of Ilex paraguariensis decreases oxidative tissue damage in the colon without fecal stream regardless of the time of irrigation.

Edema quantification by computerized morphometry as an evaluation parameter for the resistance of colon anastomoses

OBJETIVO: Verificar a validade do emprego da morfometria computadorizada, como metodo de analise quantitativa da interferencia do edema na cicatrizacao das anastomoses colicas. METODOS: Foram utilizados 45 ratos, Wistar, femeas adultas, divididas em tres grupos de 15 animais segundo a data do sacrificio ter sido realizada no primeiro, segundo e setimo pos-operatorio. Cada grupo foi subdividido em grupo principal, constituido de 10 animais, onde alem da analise morfometrica computadorizada quantitativa do edema na camada submucosa foi verificada a resistencia da anastomose colica a pressao de explosao e um grupo controle, constituido de cinco animais, onde se estudou isoladamente a quantificacao do edema. RESULTADOS: Os resultados encontrados pelo metodo morfometrico computadorizado constataram que existe reducao de 7%, em valores percentuais, da presenca do edema durante a primeira semana pos-operatoria e confirmaram que existe relacao inversa, estatisticamente significante (p< 0,001), entre a presenca de edema e a resistencia a pressao de explosao da anastomose. CONCLUSAO: O emprego da morfometria computadorizada e metodologia fidedigna, rapida, objetiva e de baixo custo na quantificacao de edema nas anastomoses colicas.

Influência da localização do tumor na expressão tecidual da proteína p53 em doentes com câncer colorretal: estudo de 100 casos

BACKGROUND: The objective of this study was to investigate if there are any differences in tissue expression of p53 protein according to tumor location in colorectal cancer patients. METHOD: One hundred colorectal adenocarcinoma patients (54 women) of mean age 59.8 years were studied. Expression of p53 protein was analyzed through immunohistochemistry, using anti-p53 monoclonal antibodies and the streptavidin-biotin-peroxidase technique. Correlations between tissue expression of p53 protein and the following variables were investigated: gender, age, histological grade, histological type, tumor size, TNM staging, depth of intestinal wall invasion, lymph node involvement, angiolymphatic invasion, and proximal or distal tumor location in relation to the splenic flexure. For statistical evaluation of the relationship between p53 protein expression and these variables, the chi-squared test was used, with the significance level set at 5% (p<0.05). RESULTS: There was positivity for p53 protein in 75% of the cases. Among the different variables considered, a greater tendency towards expression of the mutant protein was found in relation to age (p=0.001), a histological grade (p=0.001), a histological type (p=0.001), advanced TNM staging (p=0.001), deeper depth of colon wall invasion (p=0.001), lymph node involvement (p=0.001), angiolymphatic invasion (p=0.02) and distal location to the splenic flexure (p=0.001). However, there was no relationship with gender (p=0.49) or tumor size (p=0.08). CONCLUSION: The results from this study allow the conclusion that the expression of mutant p53 protein occurs more frequently in tumors located distally to the splenic flexure.

Effects of protein depletion and repletion on experimental open wound contraction

A controlled comparative study was conducted on the contraction of open wounds in protein-depleted and depleled-repleted Wistar rats. The wounds were photographed on days 1, 4, 8, 11, 15, 18, and 22 after infliction. The slides were projected and the areas corresponding to the wound were measured by planimetry. The results were analyzed using exponential regressions. Wound contraction was slowed in the protein-depleted animals but was normalized in the animals repleted immediately after the wound was produced. Comparing these results with observations from previous studies, the authors inferred that deficiencies in wound contraction in depleted animals are caused by morphological and functional changes in the granulation tissue. These deficiencies are promptly corrected by protein repletion.

The effects of protein malnutrition on wound contraction, an experimental study

The effects of protein malnutrition on wound contraction experimentally produced in Wistar rats were studied. The wounds were photographed on the first, fourth, eighth, eleventh, fifteenth, eighteenth, and twenty-second days. From dressings made from the projection of transparencies the contracted wounds were measured with a planimeter. Open wounds contracted more slowly in the malnourished group. Matching these observations with histopathological findings based on serial observations in these same animals, the differences between the contraction of open wounds in poorly nourished animals and in the control group seem to be associated with delay in the formation and the poor quality of granulation tissue in the malnourished.

Proporção de linfonodos metastáticos como variável independente de prognóstico no câncer colorretal

In patients with colorectal cancer, the compromising of the lymph node is one of the most important prognostic factors. Aim: The aim of this study is to determine the prognostic independent value of relation between compromised and examined lymph nodes, (LNR) in patients with colorectal cancer. METHOD: One hundred and thirteen 113 patients (62 women) with colon ad upper rectum cancer were studied. Fifteen patients were staged to the stadium I of the TNM classification, 44 to II, 42 to III and 24 to the stadium IV. The lymph node ratio rate was determined by the relation between total number of compromised and examined lymph nodes. The patients were divided in three groups according to the proportion of compromised lymph nodes: LNR-0: when there was no lymph node involvement; LNR-1: when there was compromising of up to 20% of the examined lymph nodes and LNR-2: when there was compromising in 21% or more of the examined nodes. The relations between lymph node ratio, number of removed lymph nodes and number of compromising lymph nodes by cancer were determined. Patients younger than 18 years old who were submitted to neoadjuvant quimioradiation protocol were excluded as well as the ones who had less than 12 lymph nodes removed. The clinical and histopathological variables were analyzed through descriptive statistic. The correlation between the variables was valued by Spearman correlation test. The five years survival was determined by the tests of Kaplan-Meier, Log-rank and the multivariate analysis of the prognostic variables by the Cox model establishing level of significance of 5 % (p=0.05). RESULTS: There was significant difference in the five years overall survival in patients classified in the different groups of LNR (p=0.009). Patients of the group LNR-0 presented five years overall survival bigger than 80%, while in those classified to the groups LNR-1 and LNR-2, the five years overall survival was less than 60% and 40%, respectively. The number of compromising lymph nodes alone was correlated to the five years overall survival (p=0.03). The multivariate analysis demonstrated that the LNR is an independent prognosis variable of the five years overall survival (p=0.009). There was relation between the total number of compromised lymph nodes and the LNR (p=0.00001, with rs=0.977). CONCLUSION: The results of the present study showed that the LNR can be considered an independent prognostic variable of overall survival in patients with colorectal cancer.

Hippocampal plasticity in rats submitted to a gastric restrictive procedure

Abstract Bariatric surgery has been the most effective therapeutic intervention for morbidly obese patients. However, recent evidence has shown that this procedure may cause serious neurological complications such as Wernicke encephalopathy, depression, and memory impairment. With this in mind, we conducted an experimental study to investigate whether weight-reduction surgery would promote morphological changes in the hippocampal formation, a brain region linked to cognitive and emotional processes. To do so, the present study evaluated the hippocampal expression of parvalbumin interneurons in rats submitted to a gastric restrictive procedure (experimental phytobezoar). Our results demonstrated that rats with gastric-reduced capacity presented a significant increase in the expression of the parvalbumin interneurons in the hippocampal CA1 and CA3 subfields. These data are the first experimental evidence that restrictive bariatric surgery may alter hippocampal cytoarchitecture.

Description of a new experimental model skin flap for studying skin viability in rats

PURPOSE To describe a new experimental flap for studying skin viability in rats. METHODS Twenty male Wistar rats weighing between 250-300g were divided into two groups: group A - McFarlane technique, a 4 x 10cm flap was used (McFarlane); and in group B modified McFarlane technique, a 3 x 10cm flap was used. Seven days later, the animals were sacrificed and the area of necrosis was evaluated in both groups. RESULTS Group A presented necrosis in 3% of the total area of the flap (CI: 0.01-0.05), Group B presented necrosis in 37% of the total area of the flap (CI: 0.29-0.46), (p<0.001). CONCLUSION The modified McFarlane flap presented a larger area of necrosis and could be an adequate experimental model of skin flap viability.