Evaluation of small caliber vascular prostheses implanted in small children: activated angiogenesis and accelerated calcification

Healing characteristics of small-caliber vascular prostheses used in small children have rarely been observed because removing specimens are troublesome. Modified Blalock Taussig shunt procedures were performed using small caliber expanded polytetrafluoroethylene (ePTFE) vascular grafts and fabric grafts in 13 patients with congenital heart disease. At the time of total corrective procedures, a piece of 10 ePTFE grafts in 10 patients and six fabric grafts in four patients were removed from the distal pulmonary anastomosis, and evaluated. The implantation duration was from 11 months to 5 years and 7 months (mean, 2 years and 6 months). At removal, average patient age was 4 years and all grafts were patent. Microscopically, the wall of three ePTFE grafts were calcified, and macrophages were immunohistologically observed in the graft wall. Thrombus formation, intimal hyperplasia, and pannus detachment was common. In the fabric grafts, many capillaries infiltrated the interstices and often reached the lumen from the perigraft side. These results suggested that in cyanotic small children, angiogenesis in and around fabric grafts was active and calcification was accelerated in ePTFE grafts. Complete endothelialization throughout the length, caused by angiogenesis, might be possible in small children when highly porous fabric vascular prostheses are used.     

A study on the effect of stacking fault energy on fatigue crack propagation as deduced from dislocation patterns

Fatigue tests of crack growth rates and transmission electron microscopy in the immediate vicinity of crack tips were performed on specimens of copper and 70/30 brass. In brass, very dense dislocations accumulated on the primary and the conjugate slip planes were observed just ahead of the crack tips, and they appeared to be not easy to move because of the difficulty of cross slip. In copper, well-defined cells were observed around the crack tips and there were frequently found cracks propagating along or across cell boundaries. On the basis of these observation results, an interpretation is put on the effect of stacking fault energy on fatigue crack growth.     

Long-term in vivo left ventricular assist device study with a titanium centrifugal pump

A totally implantable centrifugal artificial heart has been developed. The plastic prototype, Gyro PI 601, passed 2 day hemodynamic tests as a functional total artificial heart, 2 week screening tests for antithrombogenicity, and 1 month system feasibility. Based on these results, a metallic prototype, Gyro PI 702, was subjected to in vivo left ventricular assist device (LVAD) studies. The pump system employed the Gyro PI 702, which has the same inner dimensions and the same characteristics as the Gyro PI 601, including an eccentric inlet port, a double pivot bearing system, and a magnet coupling system. The PI 702 is driven with the Vienna DC brushless motor actuator. For the in vivo LVAD study, the pump actuator package was implanted in the preperitoneal space in two calves, from the left ventricular apex to the descending aorta. Case 1 achieved greater than 9 month survival without any complications, at an average flow rate of 6.6 L/min with 10.2 W input power. Case 2 was killed early due to the excessive growth of the calf, which caused functional obstruction of the inlet port. There was no blood clot inside the pump. During these periods, neither case exhibited any physiologic abnormalities. The PI 702 pump gives excellent results as a long-term implantable LVAD.     

Measurement of the spatial distribution of the maximum Josephson current in superconducting tunnel junctions

The spatial distribution of the maximum Josephson current densityJ _max is imaged in quasi-one-dimensional in-line tunnel junctions by scanning the junction surface with an electron beam and by recording the beam-induced change ofI _max as a function of the coordinates of the beam focus. In addition to the modulation of the Josephson current density for the different vortex states, the nonlocal effect resulting from the beam-induced change of the phase-difference function is observed. The results are in good agreement with the theoretical predictions. The electron beam scanning technique also serves well for imaging inhomogeneities in the barrier or in the electrodes of the junction.     

Hospital facilities available to patients with Kawasaki disease: results of a national survey of Kawasaki disease in Japan

Since 1970, thirteen nationwide epidemiologic surveys of Kawasaki disease have been conducted, and questions on the current situation of hospitals and their facilities have been included in the survey form to assess the care available to patients with Kawasaki disease. To clarify the characteristics of medical care for Kawasaki disease, this paper summarizes the present condition of hospital facilities available to patients with Kawasaki disease. A questionnaire form including questions about the situation of hospital facilities was sent to all pediatric departments of hospitals with 100 or more beds throughout Japan. The proportion of hospitals in which successive observations with echocardiography (UCG) is available (UCG available hospital) was significantly increased compared with the ninth survey (1985-86), whereas that of the hospitals in which coronary angiography (CAG) is available (CAG available hospital) was significantly decreased. Almost all (96.2%) of the patients were reported from the UCG available hospitals. The proportion of patients reported from hospitals with a set policy for intravenous gamma globulin (IVGG) therapy was 74.5%. The proportion of UCG available and CAG available hospitals and that of hospitals with a set policy for IVGG therapy correlated with the increase in the number of patients. In conclusion, hospital facilities available to patients with Kawasaki disease in Japan have satisfactory capability for diagnosis and management of Kawasaki disease.     

A case of successfully treated giardiasis in pancreas

We report a case of giardiasis in the pancreas in a patient with diabetes mellitus. The patient is interesting in the following: 1) Giardia lamblia was found only in the pancreas and not in the gall bladder by cytology on endoscopic retrograde cholangiopancreaticography (ERCP) and by cerulein-secretin test (CST). 2) ERCP revealed multiple small cysts scattered throughout the pancreas. 3) Decreased pancreatic exocrine function was recovered by treatment with metronidazole.