Masaki Aota

Protection against reperfusion-induced arrhythmias by human thioredoxin.

Adult T-cell leukemia-derived factor (ADF), identified in the supernatant of adult T-cell leukemia (ATL) cell culture, is a human homologue of thioredoxin and consists of 104 amino acids; it has two redox-active half-cysteine residues in an exposed active center. Human thioredoxin has many biological activities, including growth promotion, cell activation, and a catalase-like radical scavenging activity. We examined the protective effect of human thioredoxin (h-thioredoxin) against reperfusion-induced arrhythmias in an isolated rat heart model with 10-min regional ischemia followed by 30-min reperfusion. Male Wistar rats were assigned to six groups: a control, a superoxide dismutase (SOD 8 x 10(4) IU/L), and a catalase group (1 x 10(6) IU/L), and three groups treated with h-thioredoxin [approximately .01 microM (TRX-I group), approximately 0.1 microM (TRX-II group), and approximately 1 microM (TRX-III group)]. In the early reperfusion period, h-thioredoxin reduced the incidence of ventricular fibrillation (VF) to 8% in the TRX-II group (p < 0.01) from the control value of 75%. SOD and catalase reduced the incidence of VF to 43 and 33%, respectively (NS). During the entire reperfusion period, the incidence of VF in the SOD group was 79%, as compared to 83% in the control group. In the catalase and TRX-II groups, the incidence of VF was significantly reduced to 42 and 25%, respectively. These findings indicate that SOD failed to protect against the reperfusion-induced arrhythmias. h-Thioredoxin exerted a protective effect against these arrhythmias; a concentration of approximately 0.1 micro was the most effective.

Systemic venous aneurysms

A case of superior vena cava aneurysm combined with aneurysm of the left innominate vein is presented. For the diagnosis, it is important not only to apply imaging techniques such as superior vena caval angiography, radioisotopic angiography, and computed tomographic scans but also to have a concept of this entity in mind.

Hepatic Circulation During Nonpulsatile Cardiopulmonary Bypass

The arterial ketone body ratio, which reflects the hepatic mitochondrial redox potential (NAD+/NADH), decreases markedly during cardiopulmonary bypass (CPB). One of the reasons for arterial ketone body ratio reduction may be hepatic hypoperfusion during CPB. To evaluate the hepatic circulation under nonpulsatile CPB, the authors used color Doppler ultrasonography to measure the portal venous flow (PVF) in 24 adult patients before, during (aortic clamping and rewarming period), and after CPB. Nonpulsatile hypothermic CPB was performed at a flow rate of 2.4 L/min/m2. PVF was calculated from the product of mean flow velocity and cross-sectional area of the portal vein. PVF was maintained during CPB at 0.44 +/- 0.13 and at 0.54 +/- 0.18 L/min/m2. PVF (%) in relation to systemic blood flow was obtained by calculating PVF/CI or PVF/PI, where CI is the cardiac index and PI is the perfusion index. PVF (%) before, during, and after CPB was 18.3 +/- 9.3, 18.5 +/- 5.5, and 17.4 +/- 6.7%, respectively. In conclusion, PVF was maintained during nonpulsatile CPB at a flow rate of 2.4 L/min/m2 and depended upon systemic blood flow.

Isolated right ventricular metastasis of uterine cervical carcinoma

Isolated direct metastasis of uterine cervical carcinoma to the right ventricular endocardium is very rare. A 68-year-old woman was initially diagnosed as having stage IIIb squamous cell carcinoma of the uterine cervix, and was treated with radiation therapy. After 2 years, she developed heart failure and presented with a mass in the right ventricle. The results of further examinations were consistent with a tumor or a thrombus in the right ventricle. She underwent excision of the mass under cardiopulmonary bypass, and histopathologic examination of the resected tissue revealed metastatic squamous cell carcinoma of the uterine cervix. She was discharged 3 weeks after the operation, and underwent chemotherapy. However, she was readmitted with drug-induced interstitial pneumonia and died 5 months after the surgery. Patients with an intracardiac mass and a history of uterine cervical cancer should be suspected of having a myocardial metastasis until it is proven otherwise.

Pulmonary Hypertension Caused by Medial Hypertrophy Associated With Aortic Stenosis and Preductal Coarctation

A 7-month-old female infant with aortic stenosis, preductal coarctation, and pulmonary hypertension underwent operation. Intraoperative lung biopsy revealed marked medial hypertrophy of the pulmonary arterioles. This histopathology is compatible with persistent pulmonary hypertension in the newborn. She is alive about 5 years after the operation, but pulmonary hypertension remains. The pathogenesis is discussed.