Properties of galactocerebroside layers transferred to glassy carbon electrodes: effect of an applied electric field.

Galactocerebroside films deposited onto glassy carbon electrodes have been previously studied through the electrochemical response of a redox couple present in solution. Those experiments indicated that the film is inhomogeneous and that there are lipid-free places. In this work, we present experimental results indicating that those bare regions are formed when the electrode is introduced in an aqueous solution, and that the size and/or amount of uncovered domains increase when negative potentials are applied to the film. The experimental techniques employed for these findings are epifluorescence microscopy and ellipsometry.

Tromboembolismo pulmonar: anticoagulação ou trombólise? / Pulmonary thromboembolism: anticoagulation or thrombolysis?

A terapia trombolítica é freqüentemente indicada nos pacientes com tromboembolismo pulmonar grave, principalmente naqueles que se apresentam com instabilidade hemodinâmica, hipoxemia grave e sinais de falência do ventrículo direito ao ecocardiograma. Nas últimas três décadas, vários estudos demonstraram a superioridade da terapia trombolítica, seja com a estreptoquinase, a uroquinase, ou a rt-PA, na restauração precoce da perfusão pulmonar. A rápida lise do trombo é acompanhada pela redução da hipertensão pulmonar e dos achados ecocardiográficos compatíveis com elevação da pós-carga do ventrículo direito. Entretanto, o impacto da terapia trombolítica em relação à heparina na sobrevida dos pacientes sem sinais de instabilidade hemodinâmica, especialmente na mortalidade hospitalar, recorrência e riscos de sangramento, não está esclarecido e tem sido motivo de recentes estudos multicêntricos. Os pacientes com sinais de instabilidade clínica também deverão ser considerados para tratamento trombolítico, respeitando-se as contra-indicaçöes de seu uso geral.

[Retroesophageal hematoma with severe dysfagia after streptokinase for the treatment of the axillosubclavian vein thrombosis]. / Hematoma retroesofágico com grave disfagia após estreptoquinase para tratamento da trombose venosa axilo-subclávia.

We report the case of a 72 year-old man with advanced, stage IV, prostate cancer who underwent osteosynthesis of the cervical spine for nerve root decompression due to metastasis which was causing severe pain in his right upper limb. After three months in the hospital, he developed occlusive thrombosis of the right axillosubclavian vein as a complication of prolonged catheterization of the right subclavian vein for treatment of septicemia secondary to a hospital acquired pneumonia. The patient received thrombolytic therapy with IV streptokinase in the contralateral arm in the following dosage: 250,000 units in 15 minutes followed by 100,000 units per hour during five days. This led to total recanalization of the thrombus, with significant reduction of the arm edema. Twenty-four hours after the end of the thrombolytic therapy, the patient started to complain of dysfagia to solids and liquids and a contrasted esophagogram revealed extensive extrinsic compression of the esophagus due to a probable retroesophageal hematoma. The patient required enteral nutrition via nasoenteral tube during three months after which swallowing returned to normal and a repeat upper GI series confirmed that the hematoma had been reabsorbed, with normal passage of contrast through the esophagus. On late follow-up, the patient did not show evidence of any sequelae of deep venous thrombosis nor any residual dysfagia and is currently in use of elastic stockings and low molecular weight heparin.

[Use of tissue plasminogen activator factor for acute ischemic stroke]. / Uso do fator ativador do plasminogênio tecidual no acidente vascular cerebral isquêmico agudo.

PURPOSE: To evaluate thrombolytic therapy with rt-PA for acute stroke within 6h of symptom onset, and assessment of neurologic outcome. METHODS: We studied 6 patients, four women, mean age 63 +/- 18 years, with severe neurologic deficit within 6h of stroke onset, and with no spontaneous improvement. The stroke was embolic in 3, and thrombotic in the others. All patients were submitted to a head CT scan followed by either a cerebral angiography in 3 patients, or a transcranial Doppler, in the other 3 for assessment of arterial obstruction, and patency after thrombolytic therapy. We used 0.9 mg/kg of rt-PA, IV, over 60 min in 5 patients, and 0.5 mg/kg by intra-arterial infusion, over 60 min, in one. At the beginning a bolus of 10% of the total dose was delivered during 1 to 2 min. Head scan was repeated 24h and 7 days after treatment to detect ischemic areas and hemorrhagic complications. RESULTS: Middle cerebral artery occlusion was observed in 5 patients and posterior cerebral artery occlusion in one. The obstruction was cleared in 4 patients with persistence of the patency after 24h. A complete neurologic recovery was found in one patient, and a partial recovery in three. In two patients there was failure of arterial recanalization with no neurologic recovery. Only one patient had hemorrhagic transformation of ischemic tissue, without neurologic worsening. Death occurred in one patient due to pulmonary infection. CONCLUSION: Arterial patency with thrombolytic therapy was effective in 4 of our 6 patients. All 4 patients also disclosed a certain degree of neurologic improvement, rt-PA can be successfully used in selected patients up to 3h of the event onset, as shown in randomized studies.

[Superior vena cava and right atrium thrombosis successfully treated with streptokinase]. / Trombose da veia cava superior e do átrio direito tratada com sucesso com estreptoquinase.

The case of a 56 year-old male with acute lymphoid leukemia and no signs of activity for the last four months is reported. He presented with superior vena cava thrombosis caused by a Hickman catheter, and had positive blood cultures for Candida albicans and Staphylococcus epidermidis. Despite adequate antimicrobial therapy, the fever persisted, and the patient was submitted to surgical thrombectomy. One week following the procedure, the fever returned, and thrombosis of the superior vena cava extending to the right atrium was identified by transesophageal echocardiography (TEE). The patient underwent thrombolytic therapy with streptokinase, and no thrombus could be identified in the control TEE. No hemorrhagic or thromboembolic complication occurred. The patient was discharged with oral anticoagulation.

[Acute embolic stroke treated with rt-PA during elective coronary angiography]. / Acidente vascular cerebral isquêmico agudo embólico tratado com rt-PA durante cinecoronariografia eletiva.

A 56-year-old female with unstable angina, presented an acute embolic ischaemic stroke of right medium cerebral artery during elective coronary angiography. Complete patency was achieved after an intraarterial infusion of rt-PA (60mg/60min) with important functional improvement.

[Severe pulmonary thromboembolism caused by contraceptives in adolescents]. / Tromboembolismo pulmonar grave secundário ao uso de anticoncepcional em adolescente.

A 16 year-old female patient on oral contraceptive (gynera-ethynilestradiol+gestadone) for 4 months, presented with acute and severe pulmonary thromboembolism (PT), and was successfully treated with IV streptokinase. The contraceptive use was an importante risk factor for PT and the thrombolytic therapy provided early clinical improvement. Blood pressure, heart rate, and hypoxemia, along with echocardiography and pulmonary arteriography abnormalities, improved after this treatment.

[Hemodynamic impact of thrombolytic therapy in acute pulmonary thromboembolism]. / Repercussões hemodinâmicas da terapia trombolítica no tromboembolismo pulmonar agudo.

PURPOSE: To evaluate pre and post-hemodynamic changes after thrombolytic therapy in patients with acute pulmonary embolism with multiple pulmonary segments compromised. METHODS: Nine patients, 5 females, aged between 27 and 83 (mean 62 +/- 16) years, with the onset of symptoms preceding 7 days, were submitted to thrombolytic therapy, administered after baseline perfusion-ventilation lung scan, echodopplercardiography (ECO) and hemodynamic measurements with a Swan-Ganz thermodilution catheter. The same procedures were done after the thrombolytic infusion. Streptokinase (SK) was used in 7 (78%) cases and recombinant human tissue-type plasminogen activator (rt-PA, alteplase) in 2 with the following doses: SK-250,000 i.u. infusion over 30 min, then 100,000 i.v/h over 24 to 72 h and rt-PA-20 mg in bolus infusion, then 80 mg over 6 h. Thrombolytic was infused in pulmonary artery trunk in 8 (88%) cases and a peripheral vein in 1 (12%) case, until mean pulmonary artery pressure (PAP) reached 20 mmHg. All patients received i.v. heparin and oral anticoagulation after thrombolytic therapy. RESULTS: A significant (p < 0.05) decrease in right atrial pressure (12 +/- 3 vs 8 +/- 2 mmHg), PAP (32 +/- 5 vs 19 +/- 2 mmHg), pulmonary vascular resistance (397 +/- 125 vs 87 +/- 24 dyne.s/cm5) and increase in cardiac output (3.4 +/- 0.5 vs 5.5 +/- 1.0 l/min) and stroke volume (30 +/- 5 vs 57 +/- 10 ml/beat) were observed after thrombolytic infusion. Two patients died as a result of pulmonary infection unrelated to the embolic event or thrombolysis. Minor bleeding complications occurred in two cases and major in one patient with orthopedic prosthesis. CONCLUSION: Thrombolytic therapy exert desirable effects on hemodynamic abnormalities, achieving lungs scan and ECO improvement in patients with acute pulmonary embolism.

[Diagnosis of papillary muscle rupture in acute myocardial infarction by transesophageal Doppler echocardiography]. / Diagnóstico da rotura do músculo papilar no infarto agudo do miocárdio através do ecodopplercardiograma transesofágico.

Three patients, two females, ages ranging from 62 to 78 years were studied, evolving with hypotension, acute pulmonary edema and cardiogenic shock. One had anterior myocardial infarction, and in two, infero-posterior. Due to severe hemodynamic instability and necessity of vasoactive drug therapy to maintain adequate arterial pressure, coronary angiography was performed in two, showing total occlusion of the circumflex artery and severe mitral regurgitation. In one case, angioplasty on the circumflex artery was successfully achieved. No hemodynamic improvement was observed, however. Doppler echocardiography depicted mild to moderate mitral regurgitation in the three cases. Transesophageal echo confirmed the clinical suspicion of papillary muscle rupture: total rupture of antero-lateral papillary muscle in one patient, as well as total and partial rupture of the postero-medial papillary muscle in the other two patients. Two patients were submitted to mitral valve replacement, and the surgical findings confirmed the transesophageal echo conclusions. One of them died in the immediate pos-operative period, whereas the other was discharged from the hospital and is doing well. The third patient died before operation. Differential diagnosis of acute mitral regurgitation due to papillary muscle dysfunction or rupture was not possible by left ventriculography or by transthoracic echo. Transesophageal echo was the only exam to clearly confirm papillary muscle rupture, as should be done promptly after clinical suspicion of this severe condition arises.

[Streptokinase in severe pulmonary thromboembolism]. / Estreptoquinase no Tromboembolismo Pulmonar Grave.

Severe pulmonary embolism (PE) was treated with streptokinase in four patients, three men and one woman, age 38 to 72 (mean = 53 +/- 14) years. Before the thrombolytic therapy, all patients had pulmonary angiogram and hemodynamic parameters analyzed. The drug was infused through the distal lumen of the Swan-Ganz catheter at the pulmonary artery trunk. The initial dosage was 250,000 units "in bolus" and 100,000 units in 24 to 72 hours. The time interval between the symptoms and treatment had ranged from 2 hours to 5 days. The results are analyzed as follow: reduction on right atrial pressure, mean pulmonary pressure, pulmonary vascular resistance, an increase in the stroke volume and cardiac output. In two cases we observed total lysis, in one partial lysis and one patient died from severe form of PE and late infusion of SK. Reinfusion of the drug was necessary in one patient that had PE recurrence with reliable final result. Finally, no one had severe bleeding despite the use of the intrapulmonary catheter.

[Post infarction ventricular septal defect. Echocardiographic analysis of patients treated with positive end-expiratory pressure]. / Comunicação interventricular após infarto do miocárdio. Análise ecocardiografica de pacientes submetidos a pressão expiratória final positiva.

Interventricular septal rupture is a life-threatening complication occurring in 0.5 to 1.0% of patients following acute myocardial infarction and often results in right and left ventricular failure. This study aimed at evaluating the echocardiographic effects of PEEP on right (RV) and left (LV) ventricular dimension in three patients who developed a postinfarction septal defect and in whom acute respiratory failure was a preterminal event. The effects of PEPP on the heart remain controversial. We observed in all three patients a sudden large increase in RV dimensions and hence, probably through ventricular interdependence, a proportional decrease in LV dimensions. The progressive leftward septal displacement with increasing levels of PEEP probably contributed to reduce LV compliance. We concluded that PEEP therapy in this group of patients had no proven beneficial effects and probably contributed to further RV dilatation and failure.