Browsing by keyword "Ligation"
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Brachial artery ligation with total graft excision is a safe and effective approach to prosthetic arteriovenous graft infectionsOBJECTIVE: While autogenous arteriovenous access is preferred, prosthetic arteriovenous grafts (AVG) are still required in a large number of patients. Infection of AVGs occurs frequently and may cause life-threatening bleeding or sepsis. Multiple treatment strategies have been advocated (ranging from graft preservation to excision with complex concomitant reconstructions), indicating a lack of consensus on appropriate management of infected AVGs. We undertook this study to evaluate if, in the setting of anastomotic involvement, brachial artery ligation distal to the origin of the deep brachial artery accompanied by total graft excision (BAL) is safe and effective. METHODS: All prosthetic arteriovenous graft infections managed by a single surgeon between 1995 and 2006 were reviewed retrospectively. Patients were identified from a computerized vascular registry, and data were obtained via patient charts and the electronic medical record. RESULTS: We identified 45 AVG infections in 43 patients. Twenty-one patients (49%) demonstrated arterial anastomotic involvement and were treated with BAL; these form the cohort for this analysis. Mean patient age was 53.2 (SD 9.5) years. The primary etiologies for end stage renal disease (ESRD) were hypertension (29%), HIV (24%), and diabetes (19%). An upper arm AVG was present in 95% of patients; one (5%) had a forearm AVG. The majority of grafts were polytetrafluoroethylene (PTFE) (90%). Follow-up was 100% at 1 month, 86% at 3 months, and 67% at 6 months. No ischemic or septic complications occurred in the 21 patients who underwent BAL. CONCLUSION: BAL is an effective and expeditious method to deal with an infected arm AVG in frequently critically ill patients with densely scarred wounds. In the short term, BAL appears to be well tolerated without resulting ischemic complications. Further study with longer duration of follow-up is necessary to ascertain whether BAL results in definitive cure, or whether patients may ultimately manifest ischemic changes and require additional intervention.
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Complications and pitfalls in rat stroke models for middle cerebral artery occlusion: a comparison between the suture and the macrosphere model using magnetic resonance angiographyBACKGROUND AND PURPOSE: Investigating focal cerebral ischemia requires animal models that are relevant to human stroke. Complications and side effects are common among these models. The present study describes potential pitfalls in 3 techniques for middle cerebral artery occlusion (MCAO) in rats using magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). METHODS: Rats were subjected to temporary MCAO for 90 minutes using the suture technique (group I; n=10) or to permanent MCAO using the suture technique (group II; n=10) or the macrosphere technique (group III; n=10). Clinical evaluation was performed after 3 hours and 24 hours. After 24 hours, animals underwent MRI and MRA to determine lesion size and the intracranial vascular status. RESULTS: Hemispheric lesion volume was significantly smaller in group I (14.6%) compared with groups II (35.2%; PCONCLUSIONS: Model failures occurred frequently in all groups. MRI and MRA helps to identify animals that need to be excluded from experimental stroke studies.
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Endogenous neurotensin facilitates enterohepatic bile acid circulation by enhancing intestinal uptake in ratsInitial studies on the digestive hormone neurotensin (NT) showing that intestinal NT mRNA expression and blood levels were altered in rats fed chow containing bile acid (BA) and the BA chelator cholestyramine led us to investigate the role of NT in the enterohepatic circulation of BA. In fasted, anesthetized rats with common bile ducts cannulated for bile collection, intravenous NT infusion (10 pmol. kg(-1). min(-1)) enhanced BA output relative to control over 3 h in animals administered donor bile into the duodenum (30 microl/min). This suggested that the effect of NT was on the return of BA from the intestine to the liver, which is rate determining in the normal process. In rats prepared as described above and administered [(3)H]taurocholate ([(3)H]TC; 5 mM, 1 ml) duodenally, NT infusion (3-10 pmol x kg(-1) x min(-1)) increased the [(3)H]TC recovery rate in bile approximately twofold, whereas sulfated CCK-8 (12-50 pmol x kg(-1) x min(-1)) had no effect. To investigate the roles of endogenous NT and CCK, we administered [(3)H]TC into the rat duodenum or lower jejunum and tested the effect of the NT antagonist SR-48692 (2 nmol x kg(-1) x min(-1)) or CCK-A antagonist lorglumide (100 nmol x kg(-1) x min(-1)). SR-48692 reduced the [(3)H]TC recovery rate by congruent with 50% and congruent with 24% in the duodenum and jejunum, respectively, whereas lorglumide had no effect. These results suggest that NT or a similar peptide is an endogenous regulator of enterohepatic BA cycling, which acts by enhancing BA uptake in the intestine.
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Neuroprotective effects of MK-801 in different rat stroke models for permanent middle cerebral artery occlusion: adverse effects of hypothalamic damage and strategies for its avoidanceBACKGROUND AND PURPOSE: Permanent middle cerebral artery occlusion (MCAO) with the use of the suture technique causes hypothalamic damage with subsequent hyperthermia, which can confound neuroprotective drug studies. In the present study the neuroprotective effects of dizocilpine (MK-801) were compared in different permanent MCAO models with and without hypothalamic damage and hyperthermia. METHODS: Sixty Sprague-Dawley rats were treated with MK-801 or placebo, beginning 15 minutes before MCAO, and assigned to the following groups: suture MCAO (group I), macrosphere MCAO without hypothalamic damage (group II), or macrosphere MCAO with intentionally induced hypothalamic infarction (group III). Body temperature was measured at 3, 6, and 24 hours. Lesion size was determined after 24 hours (2,3,5-triphenyltetrazolium chloride staining). RESULTS: Hypothalamic damage was present in animals in group I and was intentionally induced in group III with the use of a modified macrosphere MCAO technique. Body temperature was significantly increased 3, 6, and 24 hours after MCAO in these 2 groups of animals. Hypothalamic damage and subsequent hyperthermia could be avoided effectively by limiting the number of macrospheres (group II). MK-801 provided a highly significant neuroprotective effect in group II but not in groups I and III. CONCLUSIONS: Hypothalamic damage with subsequent hyperthermia masked the neuroprotective effect of MK-801. This side effect can be avoided by using the macrosphere MCAO technique with a limited number of spheres. This model therefore may be more appropriate to study the effects of neuroprotective drugs in permanent focal cerebral ischemia than the suture method.