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Biomedical subjects

T Agishi

Publications and source records attributed to T Agishi.

At least 19 recordsLinked to original sources

Modified hemoglobin solution as possible perfusate relevant to organ transplantation.

A modified hemoglobin solution ( - conjugate solution, PHP solution) has very interesting characteristics such as oxygen-carrying property without corpuscular components. Experimental use of the PHP solution has shown promising possibilities as a perfusate relevant to organ transplantations. 1) Elongation of warm ischemic time in canine kidneys: Dogs survived even with the unilateral kidneys which had been exposed up to 4.5 hour warm ischemia and, thereafter, perfused with the PHP solution. 2) Elongation of perfusion preservation period of canine livers: Dogs survived with the transplanted livers which had been perfused for 48 hours with the PHP solution. 3) Successful perfusion of rat small intestine: Lewis rat intestines perfused and preserved for 12 hours with the PHP solution showed a higher survival rate compared with those with Collins or UW solution. 4) Removal of antibodies: By exchange transfusion with a total of 30-60 ml of the PHP solution, a Lewis rat hematocrit lowered to 5% while IgG went down to nil from 8970 mg/dl, IgA to 28 mg/dl from 118 mg/dl and IgM to 190 mg/dl from 897 mg/dl. This technique is expected to be applicable for removal of the naturally existing antibodies in xenotransplantation.

Animals

Evaluation of a pyridoxylated hemoglobin polyoxyethylene conjugate solution as a perfusate for small intestine preservation.

A new type of artificial blood, pyridoxylated hemoglobin-polyoxyethylene conjugate (PHP) solution, (developed by PHP research group of the department of health and welfare of Japan, and produced by Ajinomoto Co., Inc. Tokyo) as an oxygen-carrying component, has been recently devised using hemoglobin obtained from hemolyzed human erythrocytes. Recently, the studies using this solution as a preservation solution were performed in some instances. To examine the mechanism of improved viability using this solution as a preservation solution, we developed a model of orthotopic small intestine transplantation (OIT) in the rat. As a baseline study, we compared parameters of viability of the grafts preserved in Collins and UW solution to those preserved in PHP solution including a survival rate, a serum level total protein and albumin, and a change in body weight after transplantation. In our study, the simple hypothermia storage together with intestinal perfusion preservation with PHP solution was performed. Animals were divided into 6, 12, and 24 hr preservation groups. All of the rats survived after 6 hr preservation following transplantation. However, in 12 hr storage, five of six rats in PHP solution preservation survived and recovery in body weight after grafting was better than those with Collins and UW solution. We conclude that the PHP solution is, therefore, considered to possibly be a more suitable perfusate for small intestine preservation than Collins and UW solution.

Adenosine

[Evaluation of implantation of a cancer chemotherapeutic vascular access device: report of 91 cases].

Between April 1984 and December 1990, 91 patients with advanced cancer were implanted with vascular-access-devices 97 times. The results were as follows. When the patients were divided into two groups according to the implantation, namely the earlier (until December 1986) and later (from January 1987) periods, the earlier patency rate was higher than later due to improvement of instruments and progress in the implantation technique. There was no significant difference in the rate of patency or complications between the abdominal and femoral method, but the femoral method had some subcutaneous hematomas. The direct femoral pathway is less invasive, correct and effectively therapeutic method.

Catheters, Indwelling

[Autologous blood transfusion aided with erythropoietin in transurethral resection of the prostate].

Erythropoietin (EPO) with an established clinical efficacy in renal anemia has in recent years become applied as an aid to autologous blood transfusion in surgical patients. This report describes our experience with autotransfusion along with the use of EPO in transurethral resection of the prostate (TUR-P), indicating its usefulness. Ten patients with benign prostatic hypertrophy aged 60 to 74 years received 3000 units of EPO, with an iron preparation, nine times beginning 3 weeks prior to operation. Autologous blood of 300 ml was collected from the patient each at 2 and 1 week before operation and was used at TUR-P. Five other patients who underwent TUR-P with the same volume of autotransfusion accompanied by preparative medication with the iron alone served as controls. In the EPO treated group (mean age, 68.3 years) the mean value for hemoglobin concentration (Hb) was 14.0 +/- 1.6 g/dl on the day of operation, which showed a recovery rate of 94.9 +/- 5.4% (Hb recovery rate) as against the pre-EPO treatment value (mean: 14.8 +/- 1.3 g/dl). This Hb recovery rate was significantly greater (p less than 0.001) when compared to 82.2 +/- 2.5% in the control group (mean age, 68.2 years). Of the EPO treated patients, those in their sixties (n = 6; mean age, 66.3 years) exhibited a significantly higher Hb recovery rate (98.3 +/- 3.5%) than the rate (89.9 +/- 3.0%) for patients in their seventies (N = 4; mean age, 71.3 years) (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Transfusion, Autologous

Improved on-line thoracic duct drainage for lymphocytapheresis.

Lymphocytapheresis using thoracic duct drainage (TDD) is a recognized technique of extracorporeal immunomodulation for various autoimmune diseases such as rheumatoid arthritis (RA), and its clinical benefit has been reported and generally accepted. Lymphocytapheresis using TDD is very selective for removing lymphocytes (especially helper T-cells) but raises some problems such as hypoproteinemia due to the massive removal of lymph, and difficulties in repeated treatment. Along with the development of a new polyester fiber filter, we have developed a simple and effective method of lymphocytapheresis for wide adoption for these techniques. We performed lymphocytapheresis using TDD in patients with RA and previously reported its clinical efficacy indicated by the significantly lower number of peripheral lymphocytes and T4/T8 ratio. We present here our newly-developed on-line system designed to prevent hypoproteinemia. Furthermore we report on the advantages with a new subcutaneous vascular access device set up to manage the problems of repeated treatments. A small reservoir for keeping the thoracic duct open and returning lymph to the patient permitted sufficient lymph drainage and removal of lymphocytes and the clinical application of TDD is discussed.

Arthritis, Rheumatoid

Continuous blood pressure monitoring during hemodialysis.

As the number of patients suffering from circulatory problems increases, continuous blood pressure monitoring during hemodialysis is desirable. Monitoring of the fistulated venous pressure was proven to be a satisfactory substitute for that of the systemic arterial pressure, after fistulated venous pressure had been ascertained to correlate strictly with systemic arterial pressure. Utilization of a double-lumened cannula, one lumen for blood outflow and another for monitoring of fistulated venous pressure, was established and showed clinical applicability. This principle is considered to be useful not only for blood pressure monitoring, but also for activation of a dialysis machine control system.

Animals

A new method of urea removal using urease and expanded polytetrafluoroethylene membrane.

A new method for urea removal using a gas membrane is introduced along with some preliminary results. The membrane used was expanded polytetrafluoroethylene (E-PTFE) which is highly permeable to gaseous substances, while at the same time it is highly resistant to water permeation. In in vitro experiments using 10 mmol/L ammonia solution it was revealed that the single-pass reduction rate was approximately 95% at 30 degrees C at a flow rate of 200 ml/min. In animal experiments using four dogs, the extraction rate of urea was 40.4 +/- 4.4% after four hours of dialysis using 5 L dialysate. However, elevation of blood ammonia was observed in all dogs tested. Removal of ammonia by means of a gas membrane is considered to be feasible and has the possibility of being used for maintenance hemodialysis in combination with urease and charcoal.

Ammonia

Orally diluting hemofiltration.

Orally diluting hemofiltration (ODHF), herein reported, is a new technique where the body fluid is purified by cooperative procedures of dilution-supplementation with oral electrolyte solution and filtration using the RP-6 dialyzer. One uremic patient was maintained for two months on a five-hour, three-times-per-week ODHF schedule, and another patient was maintained for four months on the same regimen with no supportive hemodialysis.

Administration, Oral

Human thoracic anatomy relevant to implantable artificial hearts.

The objective of this study is to define the human thorax in a quantitative statistical manner such that the information will be useful to the designers of cardiac prostheses, both total replacement and assist devices. This paper pertains specifically to anatomical parameters relevant to the total artificial heart. Methods were developed for generating an integrated, statistical model of the anatomical structures within the human thorax. These methods involve definition of the anatomy in four areas: chest wall, pericardium, vascular connection locations, and great vessels. Results are presented in three dimensional scale views of the human thorax showing the main features pertinent to cardiac prosthesis implantation. Statistical variability of this data is also included. Measurements were obtained from a number of sources and represent both normal and diseased patients. The ERDA total artificial heart was shown to successfully fit the fiftieth percentile adult male human.

Aorta

Clinical evaluation of a pre-set ultrafiltration rate controller available for single pass and hemodiafiltration systems.

Introduction of high flux-type dialyzers, such as the RP-6, makes it necessary to devise an ultrafiltration rate controller for a single pass system. For this purpose, a new pre-set ultrafiltration rate controller has been developed and examined experimentally and clinically. The controller has twin chambers, each of which is divided into two symmetrical parts by a vertically-placed diaphragm. The diaphragm shifts repeatedly from right to left, aspirating in and driving out fresh or used dialysate alternately. If one removes a certain amount of used dialysate from a branch of the efferent line, negative pressure develops and aspirates an equal amount of water from the dialyzer. Therefore, extra dialysate obtained by a pump precisely reflects ultrafiltration rate. The controller has been used on five patients. The scheduled ultrafiltration rate was easily obtainable. The apparatus is also available for hemodiafiltration. Initial clinical trial has been promising.

Body Fluids