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Biomedical subjects

K Kawachi

Publications and source records attributed to K Kawachi.

At least 55 records · Page 3Linked to original sources
PubMed1999

Does hoarseness of voice from recurrent nerve paralysis after esophagectomy for carcinoma influence patient quality of life?

BACKGROUND: Recurrent laryngeal nerve injury caused by esophageal cancer surgery is worrisome but often temporary; it is unclear when and how the paralysis is resolved. Hoarseness of voice from vocal cord paralysis (VCP) can have detrimental effects on postoperative patients. The aims of this study were to clarify the progress of nerve paralysis related to difficulty in talking after surgery and to assess whether hoarseness influences patient quality of life. STUDY DESIGN: Between 1985 and 1996, 141 esophageal cancer patients undergoing a resection by the Akiyama procedure were cancer free 1 year after surgery. Among them, 51 patients with VCP on discharge from the hospital were retrospectively reviewed. Their VCPs, body weights, and pulmonary functions were examined yearly. They were given a questionnaire relating to the difficulty in talking 1 year after surgery. RESULTS: VCP on discharge spontaneously healed within 1 year of surgery in 21 patients (41.2%), with the mean duration of difficulty in talking 5.7 months. The remaining 30 patients had persistent VCP 1 year after surgery; 4 VCPs spontaneously healed approximately 2 years after surgery. Eleven of the 30 patients with persistent VCP, who complained of severe hoarseness at 1 year postoperatively from inability to close the glottis during exertion, showed debilitation in performance status, abilities to go up stairs, and swallowing. In the group of patients with severe hoarseness, the percentage of ideal body weight (90.6%+/-11.0%) preoperatively and pulmonary functions at 3 years postoperatively were deteriorated, resulting in 3 patients with repeated aspiration pneumonia. CONCLUSIONS: The inability to compensate for aspiration, presenting as severe hoarseness, may be dependent on the preoperative nutritional state of patients along with degree of vocal cord atrophy and a decrease in pulmonary support. Persistent nerve paralysis deteriorates quality of life until it is adequately treated.

Airway Obstruction↗
PubMed1999

Laparoscope-assisted minimally invasive treatment for choledochal cyst.

The principle of treatment of choledochal cysts is total cyst excision with hepaticojejunostomy because of the high rate of associated malignancy of the biliary system. The authors used a minimally invasive laparoscopic procedure to treat a patient with nonmalignant choledochal cyst. Although a large median laparotomy is usually used for cyst excision and hepaticoenterostomy, laparoscope-assisted total cystectomy and hepaticojejunostomy were performed with minimal skin incision. To avoid gas embolism during dissection around the hepatic hilus the surgical procedure was divided into two stages: CO2 insufflation and abdominal lifting without pneumoperitoneum. This combination of procedures was as safe and technically adequate as conventional surgery. No abnormalities were observed in liver function, and the patient could sit up in bed the first day postoperatively. Thirteen days after surgery, he was discharged from the hospital uneventfully.

Adult↗
PubMed1999

National average for the process of radiation therapy in Japan by Patterns of Care Study.

BACKGROUND: A nationwide effort is in progress to establish the actual state of radiotherapy and its quality assurance (QA) in Japan by using the Patterns of Care Study (PCS). In this study, national averages are calculated with a limited number of patients. A calculation program for national averages was prepared and applied to the radiotherapeutic processes used for esophageal cancer patients entered in the PCS. METHODS: The calculation program for national averages, which were revised on the basis of differences between individual facilities and institutional strata, was developed in accordance with Sedransk's equation for the original PCS in the USA. National averages for several aspects concerning the sampled patients who had esophageal cancer between 1992 and 1994 were calculated with these procedures. Data for facilities and stratification of institution were simulated from a national structure survey of radiation oncology in 1990. RESULTS: Values of the national average by Sedransk's equation were different from those of the simple sample average. There were significant differences in radiotherapeutic processes among stratification of institutions. For esophageal cancer, national averages were 0.129 for applications of endoscopic ultrasound, 0.599 for 'all fields treated each day' and 0.088 for application of brachytherapy. CONCLUSION: National averages for radiotherapy could be calculated. The values obtained in this PCS will be a useful measure for future QA in radiation oncology and in other specialties in Japan.

Esophageal Neoplasms↗
PubMed1999

Effects of single administration of a phosphodiesterase III inhibitor during cardiopulmonary bypass: comparison of milrinone and amrinone.

The effects of phosphodiesterase III (PDE III) inhibitors administered after aortic declamping during cardiopulmonary bypass (CPB) for open heart surgery were investigated. Ten patients (group M) were administered milrinone (50 microg/kg) after aortic declamping during CPB, 10 patients were administered amrinone (1 mg/kg) at the same time during their surgery (group A), and 10 patients served as controls with no drug administered (group C). Soon after bolus infusion of the PDE III inhibitor, perfusion pressure dropped significantly in groups M and A. However, after release of CPB and at the end of surgery, there was no difference in aortic pressure between the 3 groups. There were also no differences between the groups in heart rate, pulmonary artery pressure, and pulmonary capillary wedge pressure. After weaning from CPB, the cardiac index was high and systemic vascular resistance index was low in groups M and A. There were no significant differences in the need for additional catecholamines and time for rewarming between groups. No adverse reactions were observed. A single administration of a PDE III inhibitor during CPB was useful for post-CPB management of patients undergoing open heart surgery. Amrinone reduced perfusion pressures more than milrinone, but cardiac indices and aortic pressures after weaning from CPB showed no differences between group M and group A patients.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1998

Design of a compact synchrotron light source for medical applications at NIRS.

A synchrotron light source dedicated to medical applications is required to be compact for installation in limited spaces at hospitals. The NIRS storage ring, with a circumference of 44.8 m, is designed to accelerate electrons up to 1.8 GeV and to store a beam of 400 mA. The ring is composed of superconducting bending magnets for downsizing. A beam of 300 MeV is injected into the ring from a microtron operated at an L-band RF frequency. There are two superconducting multipole wigglers with nine poles and a maximum field of 8 T, which can produce a photon flux of about 1.4 x 10(13) photons s(-1) mrad(-1) (0.1% bandwidth)(-1) at 33 keV used for coronary angiography.

Journal Article↗
PubMed1998

Early gastric cancer associated with synchronous liver metastasis and portal tumorous embolism: report of a case.

We report herein the first known case of early gastric cancer with synchronous liver metastasis forming a portal tumorous embolism. A 62-year-old man was found to have multiple liver tumors and a portal tumorous embolism by ultrasonography. A gastroscopy subsequently showed Borrmann type III-like gastric cancer in the antrum. His carbohydrate antigen (CA) 19-9 level was elevated to 8280 U/ml, but the alpha-fetoprotein level was within normal limits. A laparotomy revealed multiple liver metastasis and subpyrolic lymph-node enlargement; a distal partial gastrectomy with group 1 lymph-node dissection for the gastric cancer in the antrum, and cannulation of the proper hepatic artery for postoperative chemotherapy were performed. Histopathologically, the cancer was found to be a medullary type well-differentiated adenocarcinoma. Subpyrolic lymph node metastasis was noted, but cancer invasion was localized to only the mucosal and submucosal layers of the stomach. Thus, the patient was diagnosed as having early gastric cancer. Adjuvant chemotherapy given through the cannula suppressed further elevation of CA19-9 levels, and a total of 26 Gy irradiation to a liver tumor, which had caused ascites by pressing on the inferior vena cava, diminished the ascites. The patient was able to remain at home with treatment for 7 months after radiation therapy, but finally died of cancer with jaundice 13 months after his operation. Therefore, although adjuvant chemotherapy and radiation therapy contributed to improving his quality of life, it could not prolong survival.

Adenocarcinoma↗
PubMed1998

Long-term benefits of internal thoracic artery-coronary artery bypass in Japanese patients.

OBJECTIVES: This study sought to determine the effects of grafting the internal thoracic artery (ITA) to the left anterior descending coronary artery (LAD) on long-term (10-year) survival, the cardiac death-free rate, and on the cardiac event-free rate in Japanese patients. BACKGROUND: The use of ITA grafts has been reported to enhance postoperative survival and to decrease the occurrence of cardiac events in the Western literature. However, the survival benefits in Japanese patients, who may have different prognoses with coronary artery disease and a different fate of a saphenous vein graft, have not yet been determined. SUBJECTS AND METHODS: A total of 954 consecutive patients who underwent coronary artery bypass graft operations (CABG) during the last 12 years at the Nara Medical University were followed and evaluated. Of these, 713 patients underwent ITA-CABG to at least the LAD (ITA group), and 241 patients received a saphenous vein graft (SVG) to the LAD (SVG group). At the time of operation, no significant difference was found between these two groups in age, sex ratio left ventricular ejection fraction, left ventricular end-diastolic pressure, cardiac index, incidence of unstable angina, or in the necessity for an emergency operation. However, those patients who received ITA-CABG had significantly higher incidences of diabetes mellitus, hyperlipidemia, and left main coronary artery disease. RESULTS: The 10-year cumulative graft patency rate for the LAD was 23% higher in the ITA group (90.3%) compared to the SVG group (67.0%), (p < .0001). Despite increased preoperative risk factors, patients in the ITA group showed significant improvements in their 5- and 10-year cumulative survival rates as well as in their cardiac death-free and event-free rates. Furthermore, this study demonstrated that ITA grafts improved the prognoses of patients with diabetes mellitus or left ventricular dysfunction and lowered both the long-term postoperative cardiac-death rate and the cardiac-event rate. CONCLUSIONS: The use of ITA grafts was effective in improving both the postoperative survival and cardiac event-free rates, and should be recommended in patients with diabetes mellitus or left ventricular dysfunction. ITA grafting to the LAD should be a routine operation in almost all categories of such patients.

Aged↗
PubMed1998

Sequential percutaneous microwave coagulation therapy for liver tumor.

BACKGROUND: Percutaneous microwave coagulation therapy (PMCT) is effective for small liver tumors. To enhance the radicality of PMCT, we developed a sequential coagulation technique. METHODS: After inserting the first guide-needle under sonography, multiple needles were placed through a disk-type introducer that was devised to guide needle puncture at regular intervals, and microwaves were irradiated. Six patients, including 4 with hepatocellular carcinoma and 2 with liver metastasis, underwent this technique for tumors of 15 to 80 mm in diameter. RESULTS: This technique can coagulate an area up to 60 mm in diameter in one session. Insertion of multiple needles, ranging from 2 to 11, was successful without complications. Three patients undergoing curative PMCT developed no tumor recurrence. The other 3 received incomplete PMCT due to the large size and location of the tumor. CONCLUSIONS: This preliminary study indicates the efficacy of this technique to facilitate and secure PMCT in selected patients with liver tumors.

Carcinoma, Hepatocellular↗
PubMed1998

Enteric absorption of FK 506: estimation by a block liver perfusion technique in rats.

This perfusion model enables a pharmacokinetic study of enteral absorption and hepatic metabolic rate simultaneously. FK 506 is absorbed mainly via the proximal small intestine and metabolized rapidly by the liver during single passage. These results may lead to further analyses of absorption and metabolism of FK 506 under various conditions.

Animals↗
PubMed1998

A case of effusive-constructive pericarditis: an efficacy of GD-DTPA enhanced magnetic resonance imaging to detect a pericardial thickening.

A 38-year-old man underwent pericardiectomy because of effusive-constrictive pericarditis. The gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) enhanced magnetic resonance imaging showed pericardial thickening separate from the effusion, which could not be shown by unenhanced computed tomography. Gd-DTPA enhanced magnetic resonance imaging could be useful for the early detection of effusive-constrictive pericarditis.

Adult↗
PubMed1998

Carbon beam dosimetry intercomparison at HIMAC.

To verify international uniformity in carbon beam dosimetry, an intercomparison programme was carried out at the heavy ion medical accelerator (HIMAC). Dose measurements with ionization chambers were performed for both unmodulated and 6 cm modulated 290 MeV/nucleon carbon beams. Although two different dosimetry procedures were employed, the evaluated values of absorbed dose were in good agreement. This comparison established a common framework for ionization chamber dosimetry between two different carbon beam therapy facilities.

Carbon↗
PubMed1998

A computational fluid dynamic study of hawkmoth hovering

A computational fluid dynamic (CFD) modelling approach is used to study the unsteady aerodynamics of the flapping wing of a hovering hawkmoth. We use the geometry of a Manduca sexta-based robotic wing to define the shape of a three-dimensional 'virtual' wing model and 'hover' this wing, mimicking accurately the three-dimensional movements of the wing of a hovering hawkmoth. Our CFD analysis has established an overall understanding of the viscous and unsteady flow around the flapping wing and of the time course of instantaneous force production, which reveals that hovering flight is dominated by the unsteady aerodynamics of both the instantaneous dynamics and also the past history of the wing. A coherent leading-edge vortex with axial flow was detected during translational motions of both the up- and downstrokes. The attached leading-edge vortex causes a negative pressure region and, hence, is responsible for enhancing lift production. The axial flow, which is derived from the spanwise pressure gradient, stabilises the vortex and gives it a characteristic spiral conical shape. The leading-edge vortex created during previous translational motion remains attached during the rotational motions of pronation and supination. This vortex, however, is substantially deformed due to coupling between the translational and rotational motions, develops into a complex structure, and is eventually shed before the subsequent translational motion. Estimation of the forces during one complete flapping cycle shows that lift is produced mainly during the downstroke and the latter half of the upstroke, with little force generated during pronation and supination. The stroke plane angle that satisfies the horizontal force balance of hovering is 23.6 degrees , which shows excellent agreement with observed angles of approximately 20-25 degrees . The time-averaged vertical force is 40 % greater than that needed to support the weight of the hawkmoth.

Journal Article↗
PubMed1998

[Successful removal of an infected pacemaker electrode adhered to the tricuspid valve].

A 77-year-old male suffered from pacemaker lead infection with pacing failure. Because he had a severe fever, we performed an interventional removal procedure with the help of a lead removal kit. However, the tip of the lead could not be withdrawn via the right internal jugular vein because it adhered tightly to the tricuspid valve. Two days later, we proceeded with an open removal procedure under cardiopulmonary bypass. The lead could be removed without any complication, and no inflammation was observed postoperatively. We report the case and discuss the indications and limitations of both the interventional and open methods.

Aged↗
PubMed1997

Minimally invasive hepatic resection using laparoscopic surgery and minithoracotomy.

To our knowledge, we introduce a new technique to treat a patient with hepatocellular carcinoma having a main tumor and a small satellite nodule in segments IV and VI, respectively. The liver was laparoscopically mobilized; the dissection line was adequately exposed through a 12-cm anterior thoracic incision. Segment VI was resected without hilar dissection or parenchymal compression. The satellite nodule was coagulated with microwaves. The patient had an uneventful postoperative recovery. This technique potentially alleviates postoperative adhesion and allows a minimally invasive surgery.

Carcinoma, Hepatocellular↗
PubMed1997

Three-dimensional arterial computed tomography and laparoscope-assisted splenectomy as a minimally invasive examination and treatment of splenic aneurysms.

For the purpose of prophylactic treatment of splenic aneurysms, both examinations and treatments should be minimally invasive. Here, we report a case of a patient who underwent three-dimensional arterial computed tomography (CT) and laparoscope-assisted splenectomy with aneurysm resection as a combination of minimally invasive examination and treatment.

Aneurysm↗
PubMed1997

The three-dimensional hydrodynamics of tadpole locomotion.

Tadpoles are unusual among vertebrates in having a globose body with a laterally compressed tail abruptly appended to it. Compared with most teleost fishes, tadpoles swim awkwardly, with waves of relatively high amplitude at both the snout and tail tip. In the present study, we analyze tadpole propulsion using a three-dimensional (3D) computational fluid dynamic (CFD) model of undulatory locomotion that simulates viscous and unsteady flow around an oscillating body of arbitrary 3D geometry. We first confirm results from a previous two-dimensional (2D) study, which suggested that the characteristic shape of tadpoles was closely matched to their unusual kinematics. Specifically, our 3D results reveal that the shape and kinematics of tadpoles collectively produce a small 'dead water' zone between the head-body and tail during swimming precisely where tadpoles can and do grow hind limbs--without those limbs obstructing flow. We next use our CFD model to show that 3D hydrodynamic effects (cross flows) are largely constrained to a small region along the edge of the tail fin. Although this 3D study confirms most of the results of the 2D study, it shows that propulsive (Froude) efficiency for tadpoles is overall lower than predicted from a 2D analysis. This low efficiency is not, however, a result of the high-amplitude undulations of the tadpole. This was demonstrated by forcing our 'virtual' tadpole to swim with fish-like kinematics, i.e. with lower-amplitude propulsive waves. That particular simulation yielded a much lower Froude efficiency, confirming that the large-amplitude lateral oscillations of the tadpole do, indeed, provide positive thrust. This, we believe, is the first time that the unsteady flow generated by an undulating vertebrate has been realistically modelled in three dimensions. Our study demonstrates the feasibility of using 3D CFD methods to model the locomotion of other undulatory organisms.

Animals↗