Growth of Floc Structure and Subsequence Compaction into Smaller Granules through Breakup and Rearrangement of Aluminum Flocs in a Constant Laminar Shear Flow.

We have constructed an outer-cylinder-rotating Couette device for high-speed shear flow in laminar flow conditions and visualized the structure formation and subsequent rearrangement of PACl (flocculant made of aluminum hydroxide gel) and kaolinite flocs by visible light imaging. In a previous report, we analyzed the case of relatively low shear rate (G-value = 29 1/s) and confirmed that the flocculation process could be separated into two stages: a floc growth stage and a breakup/rearrangement stage. Once the large bulky flocs that reached the maximum size appeared, they rearranged and densified through structural fracture and rearrangement. In this report, this process was further investigated by conducting experiments under two different high shear rates (58 and 78 1/s) at which breakup and rearrangement became more pronounced, and three different aluminum kaolinite ratios (ALT ratios) that were over and under the optimum dosage (neutralization point by Zeta potential). Visualization results confirmed that, during the growth stage, the flocculation rate could be approximated by a scaling relationship between floc size and elapsed time, which depended on the ALT ratio. After reaching the maximum size, the floc rapidly became compact and dense following adsorption of the gel, incorporating fine fragments from erosion breakup. The over and under dosages created a lot of fragments of erosion breakup, but less so in the optimum dosage. In the optimum ALT ratio, fragments did not remain because they were incorporated into the flocs and densified, and the floc size was thought to be maintained. The floc circularity distribution peaked at around 0.6 and 1, suggesting that the flocs were spherical in shape due to erosion breakup.

Surgical repair of complicated coronary arteriovenous fistula and coronary artery aneurysm in an elderly patient after 26 years of conservative therapy.

We describe a rare case of surgical repair of a coronary artery aneurysm with arteriosclerotic changes accompanied by coronary arteriovenous fistula (CAVF) after 26 years of conservative therapy. A 71-year-old woman, diagnosed with CAVF 26 years previously, was admitted to our hospital for general fatigue and dyspnea on exertion. Physical examinations revealed that the CAVF originated from the distal portion of the left circumflex artery (LCX), draining into the coronary sinus (CS); it affected the coronary artery aneurysm with arteriosclerotic changes and was calcified from the left coronary main trunk to the distal portion of the LCX. Treatment without resection of the calcified coronary aneurysm was suggested because of fear of excessive bleeding. The CAVF was closed directly from inside the dilated coronary sinus under cardiopulmonary bypass. The dilated ostium of the left coronary artery was closed using a Xenomedica patch. Coronary artery bypass grafting was performed in the left anterior descending artery (LAD) and posterolateral branch (PL) of the LCX using saphenous vein grafts. Postoperatively, the coronary aneurysm was spontaneously thrombosed for low blood flow. The bleeding might have been uncontrolled if the arteriosclerotic and calcified coronary aneurysm had been incised. Therefore, we successfully thrombosed the calcified coronary aneurysm without resection, after reducing the systemic blood flow to the coronary aneurysm and sustaining the coronary blood flow, performed with CABG.

[Predictive value of coagulative molecular markers for thromboembolism in patients with nonvalvular atrial fibrillation: prospective five-year follow-up study].

OBJECTIVES: Nonvalvular atrial fibrillation is a known risk factor for thromboembolism. This study investigated the use of coagulation markers to predict thromboembolism in nonvalvular atrial fibrillation patients. METHODS: One hundred thirty nonvalvular atrial fibrillation patients (104 males, 26 females, mean age 63.7 +/- 10.7 years) treated at the Sendai Cardiovascular Center from April 1996 to August 1997 were enrolled in this study. Coagulation markers such as prothrombin fragment 1 + 2, thrombin-antithrombin III complex and D-dimer were measured, and the patients were followed up prospectively to October 2001. RESULTS: One hundred and twenty-six patents (100 males, 26 females, chase rate 96.9%) were included in this investigation based on the medical chart and telephone interview. During five-year follow-up, 16 patients had thromboembolism accidents (3.25%/year) and two were suspected to die of thromboembolism. Three patients died of malignant disease, four of heart disease, and five of other diseases. Eight (25.8%) of the 31 patients with high levels of thrombin-antithrombin III complex and 6 (33.3%) of 18 patients with high levels of D-dimer suffered thromboembolism accidents. High thrombin-antithrombin III complex and D-dimer were statistically positive predictive markers for thromboembolism in patients with nonvalvular atrial fibrillation (p < 0.05). CONCLUSIONS: Coagulation markers such as thrombin-antithrombin III complex and D-dimer can predict thromboembolism accidents in nonvalvular atrial fibrillation patients.

Solitary cardiac metastasis of rectal adenocarcinoma.

Solitary cardiac metastasis is rarely recognized. We report a case of solitary cardiac metastasis from a rectal adenocarcinoma that was manifested as superior vena cava (SVC) syndrome. Invasion of the deep cardiac structures was so severe that only its palliative resection and right atrial reconstruction were performed using a cardiopulmonary bypass to release the SVC obstruction. The postoperative course was uneventful and the patient was discharged home without any complications. Adjuvant chemotherapy could not be performed because of the renal dysfunction. Eleven months later, the patient died from multiple metastasis of adenocarcinoma. Even though the surgery was not curative, it might be effective for release from symptoms and for elongating life expectancy.

[Complex myxoma detected by syncope: a case report].

A 23-year-old man was admitted to our hospital for evaluation of syncope and intracardiac masses. Echocardiography revealed three masses in the right ventricle and one in the left ventricle. The largest mass, 4 by 5 cm, occupied the right ventricular outflow tract and prolapsed through the pulmonary valve orifice. Right ventricular systolic pressure was 65 mmHg. A soft mass, 4 by 5 cm, was found on the left subcostal abdominal wall and multiple pigmented spots on the face and trunk. Histological examination of the resected tumors, including the abdominal soft mass, were consistent with myxoma. The combination of multiple cardiac and abdominal wall myxomas and pigmented skin lesions in this young patient is considered to be a diagnostic feature of Carney complex.