Perforation and localized dissection of the left common iliac artery during the modified Bentall procedure: a case report

We performed the modified Bentall procedure for annuloaortic ectasia in a 41-year-old man with Marfan's syndrome. Approximately 15 minutes after initiation of cardiopulmonary bypass with an arterial delivery via the left common femoral artery, perfusion volume gradually decreased and the abdomen of the patient was distended. Retrograde dissection was strongly suggested. Perforation and localized dissection of the left common iliac artery were recognized. Following repair of the lesion, the modified Bentall operation was carried out. Postoperative course was uneventful. The patient has been well for 22 months after the operation.     

Effective cross-circulation technique of venoarterial bypass for differential hypoxia condition

We examined a new technique of cross-circulation (CC) venoarterial bypass (VAB) with femoral arterial perfusion and superior vena cava drainage through a long femoral venous cannula. Six adult mongrel dogs weighing 15 to 20 kg underwent the CC-VAB with oxygenation after introduction of respiratory failure (RF). The flow of the CC-VAB was maintained at half the level of the control cardiac output, and the hemodynamic parameters were monitored. To evaluate hypoxia in the upper body, the arterial partial pressure of oxygen (PaO2 [mm Hg]) in the carotid artery and the venous saturation of oxygen (SvO2 [%]) in the pulmonary artery were measured during control, RF, standard VAB, and CC-VAB conditions. The PaO2 decreased significantly after the introduction of RF (41.7 +/- 12.4), and it returned to normal levels only after CC-VAB (151.2 +/- 24.5, p < 0.05). The SvO2 during CC-VAB (98.6 +/- 2.1) was significantly higher than that during VAB without CC (53.5 +/- 3.4, p < 0.05). These results suggest that this cross-circulation technique could be applied to patients with differential hypoxia during femoral VAB with oxygenation or percutaneous cardiopulmonary support (PCPS).     

Clinical experience for ventricular assist device

We began applying of our VAD system clinically in 1982 and have subsequently obtained good results. The first case treated with the VAD returned to normal life. In a total of 70 cases of clinical applications this system there has been instance of apparatus dysfunction. Confirming the reliability and safety promised by the results of biological experiments. Here, we report the results of clinical application of the system in a total of 61 cases between August, 1985 and March, 1989. The following conclusions were reached: 1) Satisfactory weaning and survival rates were obtained i.e. 18 cases out of 61 cases (30%) survived over one month and 13 cases (21%) are currently surviving, even in elderly patients of 60 years of age or older. 2) The weaning rate and survival rates were good after approximately 1 week of support. Detailed evaluation of the recovery of the heart and functions of other major organs has led to the conclusion that the results can be improved further when the weaning period is carefully determined. 3) With regard to surgical factors, good findings were obtained when the artificial heart-lung bypass time was less than 6 hours. The VAD can be used in the early stages without vainly attempting weaning from the artificial heart-lung bypass. 4) There were no mechanical problems with the hardware of the blood pump drive assembly, etc., or noteworthy side effects.     

New experimental findings on hot carrier effects in sub-0.1 μmMOSFET's

The behaviors of the substrate current and the impact ionization rate are investigated for deep submicron devices in a wide temperature range. New important features are shown for the variations of the maximum substrate current as a function of applied biases and temperature. It is found that the gate voltage V_gmax, corresponding to the maximum impact ionization current conditions, is quasi-constant as a Function of the drain bias for sub-0.1 μm MOSFET's in the room temperature range. At low temperature, a substantial increase of V_gmax is observed when the drain voltage is reduced. It is also shown that, although a significant enhancement of hot carrier effects is observed by scaling down the devices, a strong reduction of the impact ionization rate is obtained for sub-0.1 μm MOSFET's operated at liquid nitrogen temperature in the low drain voltage range     

Inhibition of NO synthesis induces inflammatory changes and monocyte chemoattractant protein-1 expression in rat hearts and vessels

We recently showed that chronic inhibition of NO synthesis by N(omega)-nitro-L-arginine methyl ester (L-NAME) causes coronary vascular remodeling (ie, vascular fibrosis and medial thickening) in rats. To test the hypothesis that the inhibition of NO synthesis induces inflammatory changes in the heart, we characterized the inflammatory lesions that occurred during L-NAME administration and determined whether inflammation involved the induction of monocyte chemoattractant protein-1 (MCP-1) in vivo. During the first week of L-NAME administration to Wistar-Kyoto rats, we observed a marked infiltration of mononuclear leukocytes (ED1-positive macrophages) and fibroblast-like cells (alpha-smooth muscle actin-positive myofibroblasts) into the coronary vessels and myocardial interstitial areas. These inflammatory changes were associated with the expression of proliferating cell nuclear antigen and MCP-1 (both mRNA and protein). The areas affected by inflammatory changes, as well as the expression of MCP-1 mRNA, declined after longer (28 days) treatment with L-NAME and were replaced by vascular and myocardial remodeling. Our results support the hypothesis that the inhibition of NO synthesis induces inflammatory changes in coronary vascular and myocardial tissues and involves MCP-1 expression. Results also suggest that the early stages of inflammatory changes are important in the development of later-stage structural changes observed in rat hearts.     

Experimental model and long-term prediction of photovoltaic conversion efficiency of a-Si solar cells

Degradation and recovery tests have been conducted on recent single-junction a-Si solar cells under various light intensities and temperature conditions to predict long-term stability. Saturation phenomena of the degradation of efficiency have been shown experimentally. The degradation characteristics are expressed as the second extreme distribution function of the largest value with saturation introduced. The dependence of saturation on the cell temperature and the light intensity are investigated. The worst efficiency of seasonal changes over a long term can be predicted from the saturation characteristics.     

An implantable centrifugal blood pump for long term circulatory support

A compact centrifugal blood pump was developed as an implantable left ventricular assist system. The impeller diameter is 40 mm and the pump dimensions are 55 x 64 mm. This first prototype was fabricated from titanium alloy, resulting in a pump weight of 400 g including a brushless DC motor. Weight of the second prototype pump was reduced to 280 g. The entire blood contacting surface is coated with diamond like carbon to improve blood compatibility. Flow rates of over 7 L/min against 100 mmHg pressure at 2,500 rpm with 9 W total power consumption have been measured. A newly designed mechanical seal with a recirculating purge system ("Cool-Seal") is used as a shaft seal. In this seal system, seal temperature is kept under 40 degrees C to prevent heat denaturation of blood proteins. Purge fluid also cools the pump motor coil and journal bearing. The purge fluid is continuously purified and sterilized by an ultrafiltration filter incorporated into the paracorporeal drive console. In vitro experiments with bovine blood demonstrated an acceptably low hemolysis rate (normalized index of hemolysis = 0.005 +/- 0.002 g/100 L). In vivo experiments are currently ongoing using calves. Via left thoracotomy, left ventricular apex-descending aorta bypass was performed utilizing a PTFE (Polytetrafluoroethylene) vascular graft, with the pump placed in the left thoracic cavity. In two in vivo experiments, pump flow rate was maintained at 5-8 L/min, and pump power consumption remained stable at 9-10 W. All plasma free hemoglobin levels were measured at < 15 mg/dl. The seal system has demonstrated good seal capability with negligible purge fluid consumption (< 0.5 ml/ day). Both animals remain under observation after 162 and 91 days of continuous pump function.     

Development of quality of life questionnaire for patients with colorectal cancer in surgical area--a study of reliability and validity of Tokyo Yamabuki Forum Version

We developed a new questionnaire in the surgical area based on a core quality of life (QOL) questionnaire for patients with gastrointestinal cancer. In this study, we investigated the validity and reliability of a QOL questionnaire (Tokyo Yamabuki Forum Version) for patients with colorectal cancer. The questionnaire was composed of 17 items including 5 scales (basic sensory scale, psychological scale, physiological scale, defection-related scale and active scale) and a face scale as an global scale. The time needed to answer questionnaires was expected to be around 7 minutes and the questionnaires should basically be answered by the patients themselves everyday in the hospital. The study was performed in 10 hospitals in the Tokyo area, and 394 samples collected from 21 patients with rectal and colonic cancers were analyzed. A number of respondents failed to answer the question "Do you feel your foods tasty?", so we judged this item inappropriate and deleted it from the analysis. Fifteen items, including 5 scales showed satisfactory internal consistency and construct validity in correlation and factor analyses. Performance status showed a low correlation between each item, each scale and the global scale, while SDS and STAI showed an inordinately negative correlation with the fundamental and physical scales. Especially, SDS revealed an extremely close correlation with the active scale, and STAI showed an excessive correlation with the psychological scale. In the time course of QOL under chemotherapy, reductions (aggravations) were observed in both the total score of 15 items and global scale within one week postoperatively, but after that recovered to preoperative levels at 2 weeks postoperatively. A tendency to QOL improvement was observed 2 weeks after starting chemotherapy or chemoimmunotherapy. QOL of 13 patients was measured over 3 months, and the longest term was 8 months. The results suggested that this QOL questionnaire has sufficient reliability and validity to be usable for patients with colorectal cancer in the surgical area and that this model is applicable for long-term QOL surveys and frequent measurement.     

X-ray computed tomography used to measure fiber orientation in CFRP laminates

This paper explains a new method to measure the fiber orientation in carbon fiber reinforced plastics (CFRP) laminates from X-ray CT images. In the method, the fiber orientation is analyzed by the application of digital image correlation (DIC) method to the acquired tomographic images. Using DIC, the brightness pattern, which results from the radiodensity difference between fiber and resin, is compared between two different planes in the thickness direction. Then, the three-dimensional displacement of the brightness pattern, which indicates the fiber orientation, can be measured. This study applied the proposed method to a quasi-isotropic CFRP laminate. After X-ray CT imaging, the sample was sectioned and polished. The fiber orientation was then measured experimentally using microscopy. The fiber orientation calculated using the proposed method agrees very well with the experimentally measured one. After demonstrating the validity of the proposed method, we applied it to a plain woven CFRP laminate. Results revealed that an invalid fiber orientation might be calculated for fibers parallel to the plane of the CT image, or for the fiber orientation of the pattern around the outer edge of CT images.