Rodrigo Argenta

Absence of antihyperglycemic effect of jambolan in experimental and clinical models.

The use of alternative therapies to treat diabetes, including teas prepared with different vegetables, is widespread in Brazil. In Porto Alegre, a southern city of Brazil, the tea prepared from leaves of Syzygium cumini (L.) Skeels or S. jambos (L.) Alst has been report to be used frequently by diabetic patients. We investigated the postulated antihyperglycemic effect of the S. cumini (L.) Skeels in three experiments. In the first, a randomized, parallel, placebo controlled trial, tea prepared from leaves of S. cumini did not present any antihyperglycernic effect in 30 non-diabetic young volunteers submitted to a glucose blood tolerance test. In the animal experiments, we tested the effect of increasing doses of the crude extract prepared from leaves of S. cumini administrated for 2 weeks, on the post-prandial blood glucose level of normal rats and rats with streptozotocin-induced diabetes mellitus. The treatment did not produce any antihyperglycernic effect in both models. These results do not rule out hypoglycemic effects in patients with type 2 diabetes mellitus, but strongly suggest that, for a while, the jambolan can not be recommended as an antihyperglycemic treatment.

Modelos animais de aneurisma de aorta

Experimental animal models have been used in vascular surgery for decades. The development of new interventional techniques in the endovascular treatment of aneurysms requires the creation of good experimental models to test these devices and study their impact on disease progression. The aim of this article was to review arterial aneurysm models currently available. Several distinct models have been described but none of them satisfies all the requirements of an ideal aneurysm model. Large animal models are appropriate for training, study of alterations in physiological parameters during and after device delivery, and integration of this device in the vessel wall. Significant disadvantages include difficulty in handling, high costs, difficult maintenance, and government regulations, hindering the availability of several animal species. Small animal models, such as rabbits and mice, despite being inexpensive and easily available, are not appropriate for studies of endovascular techniques because of their small-diameter vessels. To date, none of the models described could mimic all features of human aneurysms. In this review, we describe the available models and discuss their advantages and limitations.

Modelo experimental de aneurisma sacular de artéria ilíaca comum com pericárdio bovino em suínos

Objective: To develop an experimental model of saccular pseudoaneurysm of the common iliac artery with bovine pericardium in pigs. Method: The animals used were two 30-kg female pigs from the Landrace specimen. The animals were submitted to general anesthesia and laparotomy with extraperitoneal access to infrarenal aorta and the iliac arteries. After systemic heparin and clamping, the iliac artery was opened and the pericardium sutured to the vessel wall. All animals were confined for 3 weeks and were sacrificed after performing an arteriography to verify the patency of the aneurysm. Result: All animals survived the procedure and the aneurysms were patent. No rupture was detected. Conclusion: This is a feasible pig model of iliac artery aneurysm with potential for further studies to develop new endovascular prostheses.

Efeitos a curto prazo de "stents" não recobertos e recobertos com politetrafluoroetileno em aorta de suínos: um modelo experimental

PURPOSE: To report an experimental study evaluating, through digital morphometry, the intimal thickening of the arterial wall after the implant of auto-expandable stainless steel stents covered or not with polytetrafluoroethylene (PTFE) in the pig aorta. METHODS: In three groups of pigs a 12 F sheath was inserted in distal abdominal aorta. Group I animals (n=5) served as control. Group II animals (n=10) received an auto-expandable uncovered metallic stent. On group III animals (n=10) an auto-expandable stent covered with PTFE was inserted. After four weeks the animals were killed, the specimens were harvested and the intimal thickening was quantified by morphometric analysis. RESULTS: In the comparison among groups I, II and III referring to intimal, medial area and intimal index, it was not observed statistically significant variation. Differences were identified among groups referring to luminal proximal (p=0,036) and distal areas (p=0,044). Through multiple comparison tests for Kruskal-Wallis it was identified a difference between groups I and II. However, when these variables were controlled by weigh factor (luminal area/weigh relation), this difference was not observed anymore. CONCLUSION: In this short term study, the PTFE covering is not associated to further intimal thickening besides that promoted by the metallic mesh in large arteries and in high flow conditions.

Aterogênese em artéria ilíaca comum de suínos submetidos à homocisteinemia induzida pela ingestão de metionina

Objective: To assess the effects of induced homocystinemia in the swine iliac artery. Material and method: A comparative experimental study with two homogeneous groups of seven pigs from the Macao specimen, weighed between 20 and 30 kg, which were assessed during 30 days. The pigs were divided into two groups. One of them was fed with a methionine-rich diet for a 4-week period. Blood samples were collected for analyses of total cholesterol, triglycerides, HDL and homocysteine concentrations. The animals were submitted to arteriography to evaluate the patency of iliac arteries and then sacrificed. The iliac artery segment was removed for histological analysis. Results: All animals survived the procedure, and there were no significant changes in total cholesterol, triglycerides and HDL concentrations in both groups. Microscopic examinations of the control group did not show pathological changes and was similar in all analyses. In the group receiving the methionine diet, the plaques were formed by foamy macrophages, but smooth muscle cells, cholesterol crystals or inflammatory cells were not seen. The tunica media had the internal elastic lamina intact. In the control group, there was no change in homocysteine levels during the experiment. In the methionine group, there was an increase in plasma homocysteine levels, with an average value of 59.80 µmol/l after 30 days with a methionine-rich diet. Conclusion: Homocystinemia induced by methionine causes atherogenesis in the swine iliac artery.

Experimental empyema in rats through intrapleural injection of bacteria

OBJECTIVE: to evaluate empyema formation in rats through the injection of two bacteria (Pasteurella multocida and Staphylococcus aureus), using a simple, easy-to-use surgical technique. METHODS: twenty four anesthetized Wistar white rats, 250-300g in weight, submitted to right anterior thoracotomy, muscular retraction and injection of a 0.2ml solution into pleural space according the following scheme: Group I (n=12): injection of 1010 Pasteurella multocida cultured in brain heart infusion broth. Group II (n=8): injection of 1010 Staphylococcus aureus cultured in brain heart infusion broth. Group III (n=4): injection of bacterium-free brain heart infusion (control). The rats were sacrificed after seven days, and pleural reaction was assessed by macroscopy. Mortality, and intrathoracic liquid volume were evaluated, and bacteriological tests were also performed. RESULTS: Seven rats died within the first 48 hours in Group I (Pasteurella multocida); five completed the experiment, but none of them presented empyema. Only one animal died within the first 24 hours in Group II (Staphylococcus aureus); seven (88%) presented empyema at the time of sacrifice. All animals survived in Group III (control), without empyema or thoracic abnormalities. Pleural inoculation of Staphylococcus aureus (Group II) was significantly associated with empyema formation (P<0.001). In this group, the amount of pleural liquid ranged from 0.9 to 3.9ml. CONCLUSION: It is possible to induce empyema in rats through Staphylococcus aureus pleural injection by a simple surgical technique. Differently from other experiments, the pleural injection of Pasteurella multocida did not provoke empyema in rats.

Tratamento cirúrgico de aneurisma da artéria carótida extracraniana

Aneurysms of the supra-aortic trunks are rare conditions that can cause peripheral neurological conditions or embolization resulting in stroke. The upper airways can even be affected and rupture is potentially fatal. We present a case of a patient with an aneurysm of the carotid bifurcation who was treated conventionally with reconstruction of the carotid bifurcation using a venous patch. Surgical treatment enabled accurate histopathological diagnosis and anatomic correction of the carotid bifurcation.

Indução de empiema em ratos através da inoculação pleural de bacterias

Objetivo: avaliar a inducao experimental de empiema em ratos, atraves da inoculacao intrapleural de duas bacterias (Pasteurella multocida e Staphylococcus aureus), utilizando tecnica cirurgica simples e de facil execucao. Metodos: foram utilizados 24 ratos albinos da raca Wistar, de ambos os sexos, pesando entre 250 e 300g, que, apos a anestesia geral, foram submetidos a toracotomia anterior direita, afastamento da musculatura e inoculacao de 0,2 ml de solucao, conforme descricao a seguir: grupo I (n = 12), inoculacao de Pasteurella multocida, 10 10 unidades formadoras de colonia/ml cultivados em caldo cerepo-coracao; grupo II (n = 8), inoculacao de Staphylococcus aureus, 10 10 unidades formadoras de colonia/ml cultivados em caldo cerepo-coracao; e grupo III (n = 4), inoculacao de caldo cerepo-coracao esteril (controle). Os animais foram sacrificados em ate 7 dias, e a intensidade da reacao pleural analisada macroscopicamente conforme escala padronizada. Tambem foram avaliados a mortalidade, o volume de liquido na cavidade pleural e o exame bacteriologico (animais mortos e liquido pleural). Resultados:no grupo I (Pasteurella multocida), sete ratos morreram nas primeiras 48 horas de experimento. Cinco ratos foram sacrificados no periodo programado, mas nenhum deles apresentava empiema. No grupo II (Staphylococcus aureus), somente um animal morreu nas primeiras 24 horas, os outros 7 (88%) foram sacrificados e apresentavam empiema. No grupo III, considerados controles, todos os animais sopeviveram, nao se observando nenhuma anormalidade toracica ao sacrificio. Analisando conjuntamente os grupos, a inducao de empiema esteve associada de maneira significativa a inoculacao de Staphylococcus aureus no espaco pleural (p < 0,001). A quantidade de liquido obtida na cavidade pleural dos ratos deste grupo variou de 0,9 ml a 3,9 ml. Conclusoes: e possivel induzir a formacao de empiema em ratos, utilizando tecnica cirurgica simples, com a inoculacao de Staphylococcus aureusno espaco intrapleural. A Pasteurella multocida, diferentemente do que ocorre em outros modelos animais, nao foi capaz de induzir empiema nos ratos