A preliminary study of microcapsule suspension for hemolysis evaluation of artificial organs

A microcapsule suspension, a substitute for animal blood in hemolysis tests, has been developed for evaluation of the absolute hemolytic properties of circulatory artificial organs. The microcapsule suspension was made by dispersing microcapsule slurry into an ethylene glycol sodium chloride solution. The microcapsule slurry was composed of a leuco dye solution and polyurethane membrane made by the reaction between aliphatic poly-isocyanate and polyamine by interfacial polycondensation. The microcapsule was a small particle containing dye inside. The microcapsule suspension was white; the diameter of the microcapsules was from 5 to 100 microns. The specific gravity of the suspension was 1.024, and the membrane was elastic. The fluid showed Newtonian characteristics, different from animal blood, and its viscosity was approximately 5.8 mPa.s. After the microcapsules were destroyed, the leuco dye was extracted with n-hexane from the suspension and was measured by spectroscopy after being colored with acid ethanol. Hemolysis can be regarded as a fatigue fracture of cell membranes rather than a static fracture. The destruction of microcapsules by a Potter type tissue grinder was observed at a low stroke number region and was compared to rat blood. Moreover, hemolysis tests of a commercially available centrifugal blood pump and the prototype of our centrifugal pump for mechanism checks were carried out with bovine blood. The hemolysis level of the prototype pump increased with time while the hemolysis level of the commercial blood pump did not change as much as that of the control when both pumps were tested with the microcapsule suspension. These results are similar to tests utilizing bovine blood. Therefore, hemolysis tests of circulatory artificial organs completed with microcapsule suspension are expected to provide results similar to tests with animal blood.     

Correlation of anatomic and hemodynamic features with aortic valve leaflet deformity in doubly committed subarterial ventricular septal defect

Summary The records of 153 patients with doubly committed subarterial ventricular septal defect (DCVSD) who underwent intracardiac repair were analyzed to evaluate factors responsible for aortic valve leaflet deformity. The patients were divided into two groups according to their echocardiographic and angiographic features as well as anatomic findings at operation: DCVSD without (17/153, 11.1%) and with arterial valve offsetting (136/153, 88.9%). Aortic regurgitation (AR) was much more prevalent in the patients with (50.0%) than in those without leaflet deformity (2.2%,P < 0.01). Arterial valve offsetting is one of the major contributing factors to the development of leaflet deformity, accounting for 5.9% in the patients without offsetting and 46.3% in those with offsetting (P < 0.01). Among the patients with arterial valve offsetting, the pulmonary-to-systemic pressure ratio was significantly higher (P < 0.01) in the patients without (0.76 ± 0.14) than in those with leaflet deformity (0.36 ± 0.12), suggesting that pulmonary hypertension might prevent the aortic valve leaflet from prolapsing in DCVSD. In addition, increased severity of aortic valve leaflet deformity and subsequent AR were observed with increasing age. These results suggest that aging and the presence of arterial valve offsetting as well as the absence of pulmonary hypertension might be factors responsible for aortic valve leaflet deformity and subsequent AR in DCVSD. The anatomic and hemodynamic features in DCVSD have a great impact on the development of aortic valve leaflet deformity and subsequent AR.     

Objective for clinical use of particle radiations with high LET

Radiation therapy has made a steady progress in local control of cancer following introduction of megavoltage radiations. Nevertheless, the fact that the doses delivered to the target volume are strongly dependent on the radiation tolerance of the surrounding normal tissues still remains a critical problem. Particle radiations have offered an impact in radiation therapy to improve further local control of cancer. Clinical experiences performed with fast neutrons and protons indicate that the features of high LET radiations will be realized by use of radiations with excellent dose distributions. Heavy ions characterized by Bragg peak with high LET will be introduced with an emphasis to confirm the doses delivered to the target volume.     

A successful surgical treatment of cor triatriatum with VSD, PDA and CoA

A successful repair of cor triatriatum with VSD, PDA and CoA is reported. A two-month-old boy was admitted for evaluation of growth failure and cyanosis. Physical examination on admission revealed systolic murmurs at left sternal border. Chest X-ray showed increased pulmonary vascularities without cardiomegaly. Echocardiography showed abnormal wall in left atrium with VSD, PDA and CoA. An emergency operation consisting of patch closure of VSD, ligation of PDA and resection of the anomalous left atrial membrane were performed. At postoperative course, an episode of pulmonary hypertension crisis happened. But the patient tolerated this episode and survived.     

Present status of high LET radiation therapy--fast neutron radiotherapy in Japan

More than 1,900 patients of advanced and inoperable malignant tumor were treated with fast neutron radiotherapy using 30 MeV (d-Be) and 14 MeV (d-Be) beams at NIRS and IMS between 1975 and 1986. Protocols were largely nonrandomized. Some results have been obtained: 1) results with mixed beam studies for advanced squamous cell carcinoma of the uterine cervix have been equivocal compared with the photon controls. 2) some trends of local control have been observed in the trial of esophageal cancer, early cases of adenocarcinoma of the lung and malignant melanoma. 3) significant better results were observed in the pancoast type lung cancer and osteo sarcoma which was treated by the systemic multimodal treatment. It is concluded that neutrons are efficacious for certain specific tumor types owing to some biological effects, however the problem of inferior dose distribution was the weakness of neutron therapy at present.     

Quantitative analysis of pulmonary vascular disease in total anomalous pulmonary venous connection in sixty infants.

A quantitative analysis of small pulmonary arteries, pulmonary veins, and lymphatic vessels was conducted in autopsy cases of total anomalous pulmonary venous connection. The materials were obtained from 60 cases of total anomalous pulmonary venous connection without asplenia or pulmonary stenosis, ages ranging from 2 days to 19 months at the time of death (mean age 2.2 months). Pulmonary arterial pressure had been measured in 32 of these patients before death. Twenty cases of ventricular septal defect with pulmonary hypertension and 15 normal individuals were used as the control group. The mean thickness of the media of small pulmonary arteries and veins was 12.7 and 7.6 microns, respectively, in the total anomalous pulmonary venous connection cases, both values being significantly larger than those for normal and ventricular septal defect cases. No changes in thickness with aging were found. Medial thickness in the arteries and veins was greater in the cases of pulmonary venous obstruction than in those without such obstruction. The medial thickness of small pulmonary arteries in total anomalous pulmonary venous connection cases correlated with increased pulmonary arterial pressure. When the patients with the same pulmonary arterial pressure levels were compared, the medial thickness was always greater in those who had total anomalous pulmonary venous connection than in those who had ventricular septal defect. The medial thickness of pulmonary veins was also highly correlated with increased pulmonary arterial pressure in total anomalous pulmonary venous connection. The severity of the intimal lesions was milder in those who had total anomalous pulmonary venous connection than in those who had ventricular septal defect, suggesting the protective role of the thickened pulmonary arterial media against development of intimal lesions. Intimal fibrous thickening of pulmonary veins was not seen in the cases of ventricular septal defect, but it was present in 45% of the total anomalous pulmonary venous connection cases. Lymphangiectasia was characteristically present in 62% of the total anomalous pulmonary venous connection cases. Interstitial emphysema was often a complication of lymphangiectasia, and it led to eight postoperative deaths.