Mário Roberto Vizioli

Formas termolisada e viva de leveduras na redução de toxicidade causada por aflatoxinas

As aflatoxinas sao metabolitos hepatotoxicos produzidos por algumas linhagens de Aspergillus flavus, A. parasiticus e, eventualmente, por A. nomius sobre grande numero de produtos agricolas. Esta pesquisa foi conduzida para avaliar a capacidade de Saccharomyces cerevisiae, nas formas termolisada e desidratada viva, em reduzir os danos causados por aflatoxinas. Para tal, foi preparada uma dieta basica e desta se obtiveram quatro formulacoes: uma como controle; as demais contaminadas com aflatoxinas na concentracao de 400 mg kg-1, sendo duas com posterior adicao de 1% de leveduras, uma na forma termolisada e outra como desidratada viva. Um bioensaio com duracao de 28 dias foi efetuado com ratos Wistar. Foram realizados os estudos do peso relativo de orgaos internos e a analise do tecido hepatico dos animais. Os pesos relativos de orgaos internos de animais submetidos aos diferentes tratamentos nao diferiram estatisticamente entre si; o tecido do figado dos animais submetidos a dieta livre de aflatoxinas foi adotado como padrao de isento de toxidez; o tecido hepatico dos animais que receberam dieta controle com aflatoxinas apresentaram sinais claros de toxicidade; os animais que receberam dieta com aflatoxinas + 1% de levedura termolisada apresentaram sinais de toxicidade semelhantes ao controle com aflatoxinas; o tecido hepatico dos animais que receberam dieta com aflatoxinas + 1% de levedura viva apresentaram sinais de toxicidade menores do que os animais que receberam a dieta controle com aflatoxinas. As leveduras termolisadas nao foram capazes de suprimir os efeitos das aflatoxinas; as leveduras vivas apresentaram habilidade de reduzir os efeitos promovidos por aflatoxinas.

Evaluation of radioprotective effect of carnosine (beta- alanyl-1- histidine) on the wound healing in rats

The purpose of this study was to evaluate the radioprotective effect of carnosine (beta- alanyl-1-histidine) on the wound healing in rats. Therefore, 48 male rats were submitted to a surgical procedure to perform a rectangular wound in the anterior-dorsal region. The animals were divided into 4 experimental groups randomly chosen: control; irradiated; carnosine irradiated and carnosine group. The irradiated and carnosine irradiated group were exposed to a dose (6Gy) of gamma irradiation, in the whole body, 72 hours after surgery. The carnosine and carnosine irradiated groups, in addition to the surgical procedure and the irradiation, received two doses of carnosine aqueous solution, the first one being injected 48 hours after surgery, and the second one 1 hour and 30 minutes before irradiation. The tissue repair of the 4 groups was evaluated at 4, 7, 14, and 21 days after inflicting the wound, by morphological, histochemical and histophysical methods. At all examined periods, it could be observed that the animals from the carnosine irradiated group presented a better developed granulation tissue than the irradiated group and closely similar to that of the control group. Thus, under the experimental conditions used, it was possible to conclude that carnosine is an effective radioprotective substance.

Effect of low-dose electron radiation on rat skin wound healing

The aim of this study was to assess the effect of low-dose electron irradiation on morphological features of the wound healing process in rat skin. Surgical wounds were inflicted with a 2.3 x 1.4 cm template on 84 male rats that were assigned to 4 groups: IG1, immediately irradiated; IG2, irradiated 3 days after inflicting the wound; CG1 and CG2, control groups. Rats in IG1 and IG2 groups had their wounds exposed to 1 Gy of 6 MeV electron beam radiation, immediately after surgery and on the third postoperative day, respectively. Qualitative and histophotometric evaluations of tissue repair structures were carried out. Data were analyzed by ANOVA and Tukeys test (alpha = 0.05) and regression analysis. The repair process was delayed since the first sacrifice time in both irradiated groups, but in IG1, wound healing was closer to that of CG1; whereas in IG2, the delay was more pronounced. Based on the histological findings, it is possible to conclude that a low-dose of electron radiation delayed tissue repair in rat skin. The delay was longer in the skin irradiated 3 days after the beginning of tissue repair. However, the low-energy electron irradiation did not prevent wound healing.

Effects of salivary gland active principle (parotin) on glycaemic level and hepatic glycogen content in alloxan-diabetic rats: salivary gland active principle and diabetic rats.

Abstract The diabetic young rats, after a single dose of 0.30 mg/100 g of body weight of parotin returned to glycaemic levels near to normal. The hepatic glycogen of the same animals was increased compared to the controls. Two hypotheses were suggested: (a) parotin could act as a part of parotid gland secretion with an effect synergic to insulin; (b) parotin could act at a level of membrane receptors, facilitating the carriage of glucose and promoting the activities of rhythm of hepatic glycokinase synthesis.

Effects of sialoadenectomy and parotin hormone on the development of rat sponge-induced granulation tissue.

A study was made concerning the effects of sialoadenectomy and parotin hormone administration upon sponge-induced granulation tissue of young adult rats. The effects of sialoadenectomy alone and sialoadenectomy plus a single subcutaneous injection of parotin hormone, in two different doses (0.15 and 0.30 mg), on the development of 15-day-old granulation tissue were observed. The action of parotin hormone administration without sialoadenectomy was also investigated. The results have shown that sialoadenectomy produces a retardation effect upon the development of the tissue. This effect was partially inhibited by 0.15 mg and totally eliminated by the administration of 0.30 mg of the hormone. When administered in rats which were not sialoadenectomized, the dose of 0.30 mg caused increased fibroplasia and vascularization of granulation tissue, while a dose of 0.15 mg did not cause any significant difference when compared to the control tissue.

Lipid components of human dental periapical lesions: Histochemical and histophysical observations

Abstract The distribution of different kinds of lipid was studied by histochemical and histophysical methods in human dental periapical lesions. After extraction of the implicated tooth, the lesion was separated from the root and subjected to special methods for detection of lipids. Staining with Sudan black B and with Nile blue sulfate and the use of acid hematein, osmium tetroxide, and birefringence were the techniques employed. Some methods for extracting lipids were used as controls. Different types of lipid were observed in the different stages of the lesions. Glycerides, free and esterified cholesterol, and phospholipids were found in these lesions. These lipids change quantitatively and qualitatively with the type of lesion.