Scielo RSS <![CDATA[Acta Cirurgica Brasileira]]> vol. 30 num. 11 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Hemodynamic changes with high infusion rates of lipid emulsion. Experimental study in swine]]> PURPOSE: To evaluate hemodynamic changes caused by sole intravenous infusion of lipid emulsion with doses recommended for treatment of drug-related toxicity. METHODS: Large White pigs underwent general anesthesia, tracheal intubation was performed, and mechanical ventilation was instituted. Hemodynamic variables were recorded using invasive blood pressure and pulmonary artery catheterization. Baseline hemodynamic measurements were obtained after a 30-minute stabilization period. An intravenous bolus injection of 20% lipid emulsion at 1.5 ml/kg was administered. Additional hemodynamic measurements were made after 1 minute, followed by a continuous intravenous lipid infusion of 0.25 ml/kg/min. Further measurements were carried out at 10, 20 and 30 minutes, when the infusion was doubled to 0.5 ml/kg/min. Assessment of hemodynamic changes were then made at 40, 50 and 60 minutes. RESULTS: Lipid infusion did not influence cardiac output or heart rate, but caused an increase in arterial blood pressure, mainly pulmonary blood pressure due to increased vascular resistance. Ventricular systolic stroke work consequently increased with greater repercussions on the right ventricle. CONCLUSION: In doses used for drug-related toxicity, lipid emulsion cause significant hemodynamic changes with hypertension, particularly in the pulmonary circulation and increase in vascular resistance, which is a factor to consider prior to use of these solutions. <![CDATA[Whole-body vibration improves fracture healing and bone quality in rats with ovariectomy-induced osteoporosis]]> PURPOSE: To investigate the effect of vibration therapy on the bone callus of fractured femurs and the bone quality of intact femurs in ovariectomized rats. METHODS: Fifty-six rats aged seven weeks were divided into four groups: control with femoral fracture (CON, n=14), ovariectomized with femoral fracture (OVX, n=14), control with femoral fracture plus vibration therapy (CON+VT, n=14), and ovariectomized with femoral fracture plus vibration therapy (OVX+VT, n=14). Three months after ovariectomy or sham surgery, a complete fracture was produced at the femoral mid-diaphysis and stabilized with a 1-mm-diameter intramedullary Kirschner wire. X-rays confirmed the fracture alignment and fixation. Three days later, the VT groups underwent vibration therapy (1 mm, 60 Hz for 20 minutes, three times per week for 14 or 28 days). The bone and callus quality were assessed by densitometry, three-dimensional microstructure, and mechanical test. RESULTS : Ovariectomized rats exhibited a substantial loss of bone mass and severe impairment in bone microarchitecture, both in the non-fractured femur and the bone callus. Whole-body vibration therapy exerted an important role in ameliorating the bone and fracture callus parameters in the osteoporotic bone. CONCLUSION: Vibration therapy improved bone quality and the quality of the fracture bone callus in ovariectomized rats. <![CDATA[Effect of alpha-7 nicotinic acetylcholine receptor activation on beta-amyloid induced recognition memory impairment. Possible role of neurovascular function]]> PURPOSE: To evaluate the effects of PHA-543613 (α7-nAChR agonist) and galantamine (acetylcholinesterase inhibitor (AChEI)) on recognition memory and neurovascular coupling (NVC) response in beta-amyloid (Aβ) 25-35-treated mice. METHODS: PHA-543613 (1 mg/kg, i.p.), and galantamine (3 mg/kg, s.c.), effects were tested in Aβ25-35 mice model of AD. α7-nAChR antagonist, methyllycaconitine (MLA) (1 mg/kg, i.p.), was used for evaluation of receptor blockade effects. Recognition memory in animals was assessed by the novel object recognition (NOR) task. NVC response was analyzed by laser-doppler flow meter in barrel cortex by whisker stimulation method. RESULTS: Both, PHA-543613 and galantamine improve recognition memory in Aβ-treated animals. However, the advantageous effects of PHA-543613 were significantly higher than galantamine. Also, pretreatment with MLA reversed both galantamine and PHA-543613 effects on NOR. Impaired NVC response in AD animals was improved by PHA-543613 and galantamine. However, MLA pretreatment disrupts this function. CONCLUSION: Activation of α7-nAChR improved recognition memory possible through enhancement of neurovascular response in Alzheimer's disease in animals. <![CDATA[Allometric relationships among body mass, MUZZLE-tail length, and tibia length during the growth of Wistar rats1]]> PURPOSE : To investigate allometric relationships among body mass (BM), muzzle-tail length (MTL), and tibia length (TL) in Wistar rats and establish their growth rate change parameters. METHODS : Eighteen male and 18 female Wistar rats were studied from the 3rd to the 21st week of age. BM, MTL, and TL were measured daily, and relative growth was compared using allometry. RESULTS : A positive correlation between BM and MTL (p&lt;0.05) and BM and TL (p&lt;0.05) was observed. Males and females showed comparable curves; however, females had turning points at a younger age. The allometric relationship between BM and MTL presented a regular increase until reaching a mass of 351 g (males) and 405 g (females). BM and TL showed an initial increase until 185 g (males) and 182 g (females), and then reached a plateau that finished at 412 g (males) and 334 g (females), to display another increase. CONCLUSIONS : The allometric relationship of body mass with animal length and tibia length was comparable for male and female rats, with female rats maturing earlier. Animal longitudinal growth occurred in a single stage. In contrast, tibia length depicted two stages of accelerated growth with an intermediate period of deceleration. <![CDATA[Mechanisms of the beneficial effect of sevoflurane in liver ischemia/reperfusion injury]]> PURPOSE: To evaluate the underlying mechanisms by which sevoflurane protects the liver against ischemia/reperfusion injury evaluate the mechanism by which sevoflurane exerts this protective effect. METHODS: Twenty-six rats were subjected to partial ischemia/reperfusion injury for 1h: one group received no treatment, one group received sevoflurane, and sham group of animals received laparotomy only. Four hours after reperfusion, levels of alanine and aspartate aminotransferases, tumor necrosis factor-a, and interleukins 6 and 10 were measured. Analyses of mitochondrial oxidation and phosphorylation, malondialdehyde content, histology, and pulmonary vascular permeability were performed. RESULTS: Serum levels of alanine and aspartate aminotransferases were significantly lower in the sevoflurane group compared to untreated controls (p&lt;0.05). The sevoflurane group also showed preservation of liver mitochondrial function compared to untreated controls (p&lt;0.05). Sevoflurane administration did not alter increases in serum levels of tumor necrosis factor-a, and interleukins 6 and 10. Sevoflurane treatment significantly reduced the coagulative necrosis induced by ischemia/reperfusion (p&lt;0.05). Pulmonary vascular permeability was preserved in the sevoflurane group compared to untreated controls. CONCLUSION: Sevoflurane administration protects the liver against ischemia/reperfusion injury, via preservation of mitochondrial function, and also preserves lung vascular permeability. <![CDATA[Remifentanil protects uterus against ischemia-reperfusion injury in rats]]> PURPOSE: To investigate the effects of remifentanil as an antioxidant and analyze the histopathologic, biochemical changes in experimental ischemia-reperfusion (I/R) exposed rat uteri. METHODS: Wistar albino rats were assigned to three groups (n = 7). 2h period of ischemia was followed by 1h of reperfusion in the I/R and the I/R-remifentanil groups. After ischemia, no drug was administered in the sham and I/R groups. In the I/R-remifentanil group, remifentanil infusion (2 μg/kg/min) was started in the ischemia period, and continued until the end of reperfusion. After the ischemic and reperfusion period, the ischemic uterine horns were removed surgically for biochemical and histopathologic examination. Tissue damage scores (endometrial epithelial glandular leukocytosis, degeneration, and endometrial stromal changes) were examined. Malondialdehyde levels and catalase, superoxide dismutase enzyme activities in tissue were measured. RESULTS: We found significantly lower epithelial leukocytosis and cell degeneration in the I/R-remifentanil group (p&lt;0.05). Remifentanil administration significantly decreased concentrations of malondialdehyde, and increased catalase and superoxide dismutase enzyme activities (p&lt;0.05). CONCLUSION: Remifentanil appears to protect the uterine tissue against ischemia-reperfusion and can be used safely in uterus transplantation. <![CDATA[Effects of metoclopramide on the expression of metalloproteinases and interleukins in left colonic anastomoses. An experimental study]]> PURPOSE : To evaluate the effects of metoclopramide on metalloproteinases (MMP) and interleukins (IL) gene expression in colonic anastomoses in rats. METHODS : Eighty rats were divided into two groups for euthanasia on the 3rd or 7th postoperative day (POD), then into two subgroups for sepsis induction or not, and then into subgroups to receive either metoclopramide or saline solution. Left colonic anastomosis were performed and then analyzed. RESULTS : On the 3rd POD, metoclopramide was associated with increased expression of MMP-1a, MMP-13, and TNF-α. On the 7th POD, the transcripts of all MMPs, TNF-α, IL-1β, IFN-γ, and IL-10 of the treated animals became negatively modulated. In the presence of sepsis, metoclopramide did not change MMPs and decreased IL-6, IL-1β, IFN-γ and IL-10 gene expression on the 3rd POD. On the 7th POD, increased expression of all MMPs, IFN-γ and IL-10 and negative modulated TNF-α and IL-6 gene expression. CONCLUSION : Administration of metoclopramide increased metalloproteinases and interleukins gene expression on the 3rd postoperative day and negatively modulated them on the 7th POD. In the presence of abdominal sepsis, metoclopramide did not change MMPs and decreased ILs gene expression on the 3rd POD. On the 7th POD, the drug increased expression of all MMPs. <![CDATA[A comparative study of the areas of osteochondral defects produced in femoral condyles of rabbits treated with sugar cane biopolymer gel]]> PURPOSE: To assess the histological response of damaged osteochondral tissue in the femoral condyles of rabbits after repairing the wounds with sugar cane biopolymer gel - compared to the control group. METHODS: The study investigated 16 New Zealand rabbits, at 90, 120 and 180 days after surgery. In all the animals, a lesion of 3.2 mm in diameter and 4 mm deep was induced in each right and left femoral condyle. Each animal has provided both knees, divided into medial and lateral condyle, resulting in 64 samples. 32 knees were divided into two groups: Right knee, medial and lateral condyles, filled with biopolymer; Left knee, medial and lateral condyles, unfilled. The anatomical specimens were removed, and subjected to histological techniques and morphometric and statistical analysis. RESULTS: In all the periods of the group under study an inflammatory reaction mediated by giant cells and mononuclear cells was found, while in the control group there was early healing produced by fibroblasts and few mononuclear cells with statistical significance between groups. CONCLUSION: The biopolymer gel caused an inflammatory reaction mediated by giant cells and mononuclear cells while the control group there was cicatrization mediated by fibroblasts. <![CDATA[Rutin ameliorates methotrexate induced hepatic injury in rats]]> PURPOSE: To investigate the possible protective effect of rutin on methotrexate induced hepatotoxicity in rats. METHODS: Twenty-two rats were divided into three experimental groups; Control-saline, Mtx, Mtx+Rutin. Hepatic tissue was taken for histological assessment and biochemical assays. Oxidative stress parameters malondialdehyde (MDA), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were investigated. Liver markers aspartate aminotransferase (AST), alanine aminotransferase (ALT) were analyzed in serum. RESULTS: Mtx+Rutin group showed lower histological injury compared to Mtx group, MDA and ALT levels were increased, while SOD and GSH-Px were decreased in Mtx group compared with Control-saline group. MDA and ALT levels were increased, while SOD and GSH-Px were decreased in Mtx group, compared with Mtx +Rutin group. Serum AST levels were similar among the groups. CONCLUSION: Rutin may be a potential adjuvant drug to reduce the hepatic side effects observed during Mtx therapy for various clinical conditions. <![CDATA[Comparison between hemosiderin and Technetium-99 in sentinel lymph node biopsy in human breast cancer]]> PURPOSE: To assess the safety and potential equivalence of the use of hemosiderin compared to the Technetium-99 in sentinel lymph node biopsy in human breast cancer. METHODS: Non-random sample of 14 volunteer women diagnosed with breast cancer with primary tumors (T1/T2) and clinically tumor-free axilla were submitted to the identification of sentinel lymph node using hemosiderin obtained from autologous blood injected in the periareolar region 24h before surgery on an outpatient basis. Patients received preoperative subareolar intradermal injection of Technetium-99 in the immediate preoperative period. Patients were submitted to sentinel lymph node biopsy, with incision in the axillary fold guided by Gamma-Probe, dissection by planes until the identification of the point of maximum uptake of Technetium-99, identifying the marked nodes and their colors. All surgical specimens were sent for pathological and immunohistochemical study. RESULTS: The results showed no evidence of side effects and/or allergic and non-allergic reactions in patients submitted to SLNB with hemosiderin. The SLN identification rate per patient was 100%. SLNB identification rate per patient with hemosiderin was the same as that of Technetium, with a concordance rate of 100% between the methods. CONCLUSION: Hemosiderin is a safe dye that is equivalent to Technetium in breast sentinel lymph node biopsy.