RESUMO
Cerebral vasoreactivity (CVR) was evaluated as a preoperative test in predicting cerebral tolerance to carotid clamping.A consecutive series of 115 carotid endarterectomy (CEA) cases were studied. Before surgical operation CVR was evaluated, by measuring the mean velocity of the middle cerebral artery (mv-MCA) using transcranial Doppler (TCD) at the basal condition and 20 min after intravenous administration of acetazolamide (1 g). CEA was performed under general anesthesia. TCD was used during surgery to evaluate mv-MCA and to calculate mv-MCA clamping/mv-MCA pre-clamping x100 ratio (mv-MCA%), which was used as the parameter to validate CVR.CVR did not correlate with mv-MCA% (r=0.22). There was no significant difference (P=0.09) between mean values of the non shunted subgroup and the shunted one.CVR does not seem to be suitable for evaluating cerebral tolerance to carotid clamping.
Assuntos
Estenose das Carótidas/cirurgia , Endarterectomia das Carótidas/métodos , Hipóxia-Isquemia Encefálica/diagnóstico por imagem , Artéria Cerebral Média/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana , Acetazolamida , Adulto , Idoso , Velocidade do Fluxo Sanguíneo , Inibidores da Anidrase Carbônica , Estenose das Carótidas/fisiopatologia , Constrição , Feminino , Humanos , Hipóxia-Isquemia Encefálica/etiologia , Hipóxia-Isquemia Encefálica/fisiopatologia , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/fisiopatologia , Monitorização Intraoperatória , Valor Preditivo dos Testes , Cuidados Pré-OperatóriosRESUMO
BACKGROUND: Transcutaneous oximetry was studied to select the correct amputation level for limb ischemic necrosis with possible identification of threshold value. METHODS: The method was evaluated in 30 cases (20 patients, 5 males and 15 females, of ages ranging from 61 to 93, average 73.1+/-8.5) where patients underwent amputation because of severe leg ischemia. Surgical operations were: minor amputation (toe or transmetatarsal) in 23 cases, below knee amputation in 7. Oxygen tension was measured at the dorsum foot and at the third superior of the anteromedial calf aspect. RESULTS: Results were classified as success (primary or delayed healing) or failure (necrosis at the surgical wound). Amputation was successful in 17/30 cases with oxygen tension of 0-65 mmHg (mean 32.5+/-16.1) and failed in 13/30 with oxygen tension of 0-57 mmHg (mean 7.8+/-17.3). The difference was statistically significant (p=0.0004). Sensitivity of the method resulted 88.2%, specificity 84.6%, diagnostic accuracy 86.7%, positive predictive value 88.2% and negative predictive value 84.6%. A threshold of 20 mmHg was identified: 15/17 successful cases showed values greater than 20 mmHg, while 11/13 failed cases presented values lower than the threshold. CONCLUSIONS: Following our observations and according to some reported studies, we believe transcutaneous oximetry to be the best method for selection of amputation level This is a simple, noninvasive and accurate method, which has showed itself superior to other techniques (i.e., Doppler and radioisotope).
Assuntos
Amputação Cirúrgica/métodos , Monitorização Transcutânea dos Gases Sanguíneos , Isquemia/cirurgia , Perna (Membro)/irrigação sanguínea , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Isquemia/fisiopatologia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/fisiopatologia , Sensibilidade e Especificidade , Resultado do TratamentoAssuntos
Arteriopatias Oclusivas/tratamento farmacológico , Moxisilita/uso terapêutico , Vasodilatadores/uso terapêutico , Adulto , Idoso , Feminino , Humanos , Perna (Membro)/irrigação sanguínea , Síndrome de Leriche/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Doença de Raynaud/tratamento farmacológico , Tromboangiite Obliterante/tratamento farmacológicoRESUMO
1. A seven-step procedure for preparing highly purified glutamate decarboxylase from Clostridium perfringens is described. 2. The homogeneity of the pure enzyme was established by sucrose-density-gradient centrifugation and starch-gel electrophoresis. 3. The isoelectric point of the pure enzyme is about pH4.5 and the molecular weight is 290000. 4. The pH optimum for activity is 4.7. The pure enzyme is specific for l-glutamate; beta-hydroxyglutamate is decarboxylated at a lower rate. 5. Evidence is presented that each mol of enzyme contains 2mol of firmly bound pyridoxal 5-phosphate. 6. Resolution does not occur at acid pH; by dilution with neutral or alkaline buffers the enzyme is inactivated and the coenzyme is released. 7. Reconstitution of active enzyme was obtained by protecting the apoenzyme with thiol compounds.
