963 resultados para ischemia-reperfusion


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Acute renal failure (ARF) is a frequent complication in hospitalized patients and is strongly related to increase in mortality. In order to analyze the clinical outcome and the prognostic factors in hospital-acquired ARF a prospective study was performed. Data from 200 patients with established ARF during the period of January 1987 through July 1990 were collected. The incidence of ARF was 4.9/1000 admissions. Renal ischemia (50%) and nephrotoxic drugs (21%) were the main etiologic factors. The histologic study done in 43 patients showed: acute tubular necrosis (53%), tubular hydropic degeneration (16%), glomerulopathies (16%), and other lesions (15%). Dialysis therapy was performed in 101 patients. The mortality rate was 46.5% and the most important causes of death were. sepsis (38%), respiratory failure (19%), and multiple organ failure (11%). Higher mortality was observed in oliguric patients (62.9%) than nonoliguric (34.5%) (p < 0.05) and in ischemic renal failure (56.7%) when compared to nephrotoxic renal failure (14.7%) (p < 0.05). As primary cause of death was not associated to the acute renal failure, conclude that acute renal failure is an important marker of the gravity of the underlying disease and not the cause of death.

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Objective-To determine the effect of experimental intraluminal distention on microvascular perfusion of the small colon in horses.Animals-6 mixed-breed healthy horses (mean age [+/- SD], 9.1 +/- 2 years).Procedure-Under general anesthesia, the small colon was exposed by celiotomy and 3 segments were demarcated. In 1 of these segments, intraluminal obstruction was created by placement of a latex balloon inflated to a pressure of 40 mm Hg (obstructed segment). The other segments were the sham-operated segment and the control segment. Microvascular perfusion was evaluated in the mucosal, submucosal, muscular, and serosal layers by injection of 15-mum-diameter colored microspheres into branches of the caudal mesenteric artery. Recovery of microspheres was performed by tissue digestion, washing, and centrifugation. Distribution of microspheres in the intestinal layers was evaluated by direct observation of stained frozen sections by light microscopy.Results-A significant reduction was observed in total microvascular perfusion of obstructed segments, which was 26.4% of that of control segments. This reduction was not evident in the mucosal layer.Conclusions and Clinical Relevance-Intraluminal distention of the equine small colon wall can promote ischemia by a reduction in microvascular perfusion in the intestinal wall. Intestinal layers do not seem to be affected to the same extent, because the absolute value for mucosal perfusion did not decrease in the obstructed segment.

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OBJECTIVE: the aim of this study was to determine the oral status of renal transplant recipients receiving cyclosporin A (CsA) or tacrolimus (FK-506) as immunosuppressant.SUBJECTS AND METHODS: A total of 88 renal transplant recipients receiving CsA (63 men and 25 women, mean age 51.4 years) and 67 receiving FK-506 (57 men and 10 women, mean age 33.5 years) were included in the study. Donor type, histocompatibility, cold ischemia time and prior delayed graft function were similar between the two groups. Demographics and pharmacological data were recorded for all subjects.RESULTS: the results demonstrated that CsA caused a greater number of oral diseases. A greater number of gingival overgrowth was present in patients treated with CsA. However, the combined use with calcium channel blockers increased the gingival overgrowth number. The occurrence of candida in saliva was observed in 80 renal recipients treated with CsA and 20 treated with FK-506. The presence of squamous oral carcinoma (n = 3) and herpes simplex (n = 10) was observed in patients treated with CsA. These alterations were not observed in renal recipients treated with FK-506.CONCLUSIONS: Renal recipients constitute a high-risk group for oral diseases, as they are immunocompromised. However, the FK-506 regime appears to ameliorate this effect, compared with CsA. Adequate pre- and post-transplant oral health care is recommended for these subjects, irrespective of the time interval for which the drug is administered.

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In the present study, the effects of electrolytic lesions of the anteroventral third ventricle (AV3V) region and of the medial forebrain bundle (MFB) on the pressor response induced by bilateral carotid occlusion (BCO) in conscious intact and aortic baroreceptor-denervated (AD) rats were investigated. In intact control rats, BCO during 60 s produced a pressor response that could be divided into an early response (ER = 50 +/- 3 mmHg) that reachs a peak during the first 20 s and a sustained late response (LR), smaller than ER (32 +/- 2 mmHg), observed during the last 30 s. In intact-innervated rats, AV3V lesion (2 days) reduced ER (22 +/- 3 mmHg) and LR (16 +/- 2 mmHg), whereas the bilateral MFB lesions (6 days) mainly reduced LR (9 +/- 1 mmHg). Rats with simultaneous lesion of both the AV3V region and the MFB showed additional reduction of the ER (15 +/- 3 mmHg), but not LR (11 +/- 1 mmHg) when compared to the effect of MFB lesions alone. Compared to the AV3V lesion alone, LR but not ER was reduced in rats with a double lesion. In sham-lesioned rats, AD induced a significant increase in the pressor response to BCO (ER = 75 +/- 4 mmHg and LR = 65 +/- 3 mmHg) when compared to intact controls. A similar reduction in ER and LR was observed in AD rats after AV3V (ER = 35 +/- 3 mmHg and LR = 40 +/- 2 mmHg) and MFB (ER = 49 +/- 6 mmHg and LR = 41 +/- 5 mmHg) lesions alone or combined (ER = 40 +/- 6 mmHg and LR = 35 +/- 7 mmHg). The results showed that simultaneous lesions of both the AV3V region and the MFB practically abolished the pressor response to BCO. They also suggested that aortic baroreceptor activity plays a significant role in the effects of AV3V and MFB lesions on the pressor response to BCO.

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In the present study, we investigated changes in mesenteric, renal, and hindquarter vascular resistance during the pressor response produced by bilateral carotid occlusion (BCO) in conscious, freely moving normal and denervated (aortic, carotid, or both) rats. BCO was performed using special previously implanted cuffs. In control normal rats, the increase in mean arterial pressure (MAP) during early and late responses (37 +/- 4 and 21 +/- 2 mm Hg, respectively) was related to increased renal (125 +/- 12% and 45 +/- 10%) and mesenteric (38 +/- 13% and 41 +/- 5%) but not hindquarter (14 +/- 4% and 8 +/- 7%) vascular resistance. In aortic-denervated rats, the greater MAP increase in early and late responses (57 +/- 4 and 44 +/- 4 mm Hg, respectively) compared with normal rats was related to a marked increase in hindquarter (137 +/- 26% and 106 +/- 26%) and mesenteric (104 +/- 14% and 66 +/- 9%) vascular resistance. In carotid-denervated rats, MAP increase and change in vascular resistance were similar to those values observed in control rats. Sinoaortic-denervated rats showed a greater MAP increase (34 +/- 4 mm Hg) during late response and a reduced increase in renal vascular resistance (46 +/- 6%) during early response. The present results show that 1) the pressor response to BCO in normal rats is associated with an increase in renal and mesenteric vascular resistance, 2) the aortic baroreceptors buffer the increase in mesenteric and especially hindquarter vascular resistance during BCO, and 3) the reduced pressor response in late response is probably related to a reduced increase in renal vascular resistance during this component compared with the early response.

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Our aim was to assess the effects of magnesium sulphate given by iontophoresis on the viability of random skin flaps in rats. Endovenous magnesium sulphate is used to treat pre-eclampsia and diseases of blood vessels. Iontophoresis is an electrotherapeutic method which has shown satisfactory results in controlling ischaemia within the boundaries of the area in which it was given. Forty-five adult male Wistar rats, weighing 300 to 440 g were randomly divided into three groups of 15 animals each: random skin flap (control); random skin flap treated with magnesium sulphate without electrical stimulation; and random skin flap treated with magnesium sulphate with electrical stimulation of 4 mA for 20 minutes. The treatments were applied immediately after the operation and repeated on the following two days. The percentage of necrotic area was measured on the seventh postoperative day using a paper template. For each group, the mean percentage of flap necrosis was as follows: control, 46%; magnesium sulphate without electrical stimulation, 34%; and magnesium sulphate with electrical stimulation, 42%. There was no significant difference among the groups (p=0.18). Magnesium sulphate given by iontophoresis does not increase the viability of random skin flaps in rats.

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The purpose of this study was to observe and characterize colonic and lung lesions in horses subjected to experimental distension and decompression of the small colon. Sixteen healthy adult horses were divided into 2 groups: 9 horses that were subjected to distension of the small colon by means of a latex balloon surgically implanted in the lumen and inflated to a pressure of 40 mm Hg for 4 h, and 7 horses in which the balloon was implanted but not inflated. Colonic biopsy specimens were collected before balloon implantation, at the end of the period of obstruction, and 1.5 and 12 h after decompression and were examined for hemorrhage, edema, and neutrophil infiltration; myeloperoxidase (MPO) activity and hemoglobin concentration were measured as well. At the end of the experiment, lung samples were also collected and examined for neutrophil accumulation and MPO activity. The mucosa was not affected by luminal distension; lesions were restricted to the seromuscular layer. Neutrophil accumulation and edema were observed in the samples from both groups of horses but were greater in those from the distension group, in which there was also hemorrhage, fibrin deposition, and increased MPO activity in the seromuscular layer. Similarly, there was greater accumulation of neutrophils in the lung samples from the distension group than in those from the sham-operated group, as determined by histologic evaluation and MPO assay. These findings provide new evidence of reperfusion injury and a systemic inflammatory response, followed by remote lesions, in horses with intestinal obstruction.

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Purpose - To analyse the influence of mannitol added to Krebs-Henseleit (KH) solution on the myocardium edema and myocardial function. Methods - Isolated rat heart under isovolumetric contractions studied according to Langendorff's technique were perfused with KH solution at constant flow during 90 min. The coronary perfusion pressure, diastolic and systolic pressures were recorded at every 15 min. At the end of the experiment, myocardium water content was measured in hearts perfused with KH solution (group I, n = 9) and in hearts perfused with KH solution plus 8 mM mannitol (group II, n = 8). These results were compared to non-perfused control heart (n = 9). Results - Myocardial water content was statistically higher in group I (80.8 ± 1.3%) compared to group II (78.1 ± 0.7%) and control group (75.5 ± 0.5%). Systolic arterial pressure was statistically higher in group I (86.2 ± 11.5 mmHg) compared to group II (72.7 ± 21.1 mmHg). There was no difference in the diastolic pressure between the two groups. Coronary perfusion pressure (Pp) increased progressively during the experiment in both groups. However, Pp was lower in group II than in group I. Conclusion - Mannitol added to KH solution significantly attenuates the myocardium edema in the isolated perfused rat heart.

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Acute renal failure (ARF) is a frequent complication in hospitalized patients, and is strongly related to increase of mortality. PURPOSE: To analyze the clinical outcome and the prognostic factors in hospital acquired AFR. METHOD: A prospective study was performed. Data from 200 patients with established ARF admitted during the period of January, 1987 and July, 1990 were collected. RESULTS: The incidence of ARF was 4.9/1000 admissions. Renal ischemia (50%) and nephrotoxic drugs (21%) were the main etiologic factors. The histologic study done in 43 patients showed: acute tubular necrosis (53%), tubular hydrophic degeneration (16%), glomerulopathies (16%) and other lesions (15%). Dialysis therapy was performed in 101 patients and the main indications were: uremia (67%), hypervolemia (22%) and hyperkalemia (9%). The mortality rate was 46.5% and the most important causes of death were: sepsis (38%), respiratory failure (19%) and multiple organs failure (11%). Treatment withdraw was the cause of death in 2 patients. Higher mortality was observed in oliguric patients (62.9%) than non-oliguric (34.5%) (p < 0.05) and in ischemic renal failure (56.7%) when compared to nephrotoxic renal failure (14.7%) (p < 0.05). This difference was maintained when the comparison was done only between dialyzed patients. CONCLUSION: As primary cause of death was not associated to the acute renal failure, we conclude that acute renal failure is an important marker of the gravity of the underlying disease and not the cause of death.

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In this study we present the technical details, adaptations and modifications of the original procedure of pancreaticoduodenal transplantation in rats described by Lee et al. in 1972. We also present the results and technical failures observed in a follow-up of 12 years. From March, 1982 to December, 1994, we performed in the Laboratory of Surgical Technique and Experimental Surgery of Faculty of Medicine, Botucatu - UNESP, Brazil, 665 duodenopancreatectomies in donor rats and 592 surgeries for revascularization of the pancreatic graft in recipient animals. The observed percentage of technical failures in donor rats was 11% due to bleeding and/or vascular complications, irregular flushing of the graft with saline and respiratory insufficiency. In recipients of grafts, we observed a percentage of technical failures of 22,5% due to porto-caval thrombosis, vascular bleeding, pancreatitis and graft ischemia. In both surgeries, the successful results are directly related to the technical performance of the surgeon and the cares in the postoperative period.

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In order to evaluate the role of underlying disease in the high mortality observed in acute renal failure (ARF) and risk factors related to the development of oliguric ARF in renal allograft recipients, two groups were selected: 34 patients with native kidneys, aged 16 and 57 years, and presenting ischemic ARF caused by cardiovascular collapse, with no signs of infection at the time of diagnosis; and 34 renal allograft recipients who developed ARF immediately after transplantation, without rejection. ARF was defined either as 30% increase of basal plasmatic creatinine in patients with native kidneys or non-normalization of plasmatic creatinine at day 5 after transplantation in renal allograft recipients; oliguria as diuresis ≤ 400 mL/24 h. There were no differences in age, male frequency, oliguria presence and duration, need for dialysis, and infection episodes for renal allograft recipients and patients with native kidneys. The development of sepsis (3% and 41%) and death rate (3% and 44%) were higher in patients with native kidneys (p < 0.01). The renal allograft recipients with both oliguric (n = 18) and nonoliguric (n = 16) ARF were evaluated and no difference was observed in the recipient's age, donor's age, cold ischemia time, time elapsed until plasmatic creatinine normalization, donor's plasmatic creatinine or urea, and mean arterial pressure. No differences were observed between the groups regarding frequency of infection episodes during ARF and frequency of death. In conclusion, renal allograft recipients presented a lower death rate and were less susceptible to sepsis. Cold ischemia time, age, and hemodynamic characteristics of the donor did not affect the development of oliguria.

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This paper intend to review recent advances in our understanding of programmed cell death, or apoptosis, and discuss implications of these basic science advances in the development of causes and potential treatments of a variety of diseases of the head and neck. Conclusions: apoptosis is now understood to be important in the normal development and survival of all multicellular organism. Deregulation of this normally tighly controlled process underlies a variety of disease states, including neoplasia, autoimmune disease, and disorders of the central nervous system. A better understanding of this process and regulation may help otolaryngologists better understand diseases relevant to this specialty and will lead to improved therapeutic interventions.

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The myocardial protection allowed great advance in cardiac surgery, decreasing the mortality and making more feasible complex surgeries. Latterly, the patient population elected for cardiac procedures has been changing towards elderly patients with ventricular function depressed and myocardial hypertrophy. The myocardial hypertrophy condition represents a great challenge since the beginning of the cardiac surgery. Several techniques have been described to protect the myocardial hypertrophy, however with no satisfactory results. In this manuscript we present the state of the art technique of myocardial protection.

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Introduction: 5-Fluorouracil (5-FU) is considered to be the backbone of colorectal cancer (CRC) systemic therapy since the great majority of recommended regimens include its administration. A clinical picture consisting of chest pain, sometimes cardiac enzyme elevation, electrocardiogram abnormalities consistent with myocardial ischemia, and normal coronary angiogram associated with 5-FU administration have been infrequently reported. The clinical dilemma is: Which chemotherapy regimen should we use in CRC patients with a previous acute coronary syndrome (ACS) associated with 5-FU? Case Report: We describe the case of a 55-year-old otherwise healthy woman with metastatic colon adenocarcinoma who presented an ACS probably secondary to arterial vasospasm while receiving continuous intravenous 5-FU infusion (mFOLFOX6 regimen). After the ACS, the patient was treated with raltitrexate plus oxaliplatin (TOMOX) and subsequently with irinotecan plus cetuximab with no other cardiac event. Conclusion: The risk of cardiotoxicity associated with 5-FU is low but real. The probable mechanism is arterial vasospasm, as suggested by our case report. Both the use of the TOMOX regimen and irinotecan plus cetuximab seems to be safe regimens to be considered in this clinical scenario. © 2009 Humana Press Inc.