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Biomedical subjects

T Agishi

Publications and source records attributed to T Agishi.

At least 163 records · Page 9Linked to original sources
PubMed1979

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↗
PubMed1979

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↗
PubMed1979

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↗
PubMed1978

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↗
PubMed1978

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↗
PubMed1978

Short-time hemodiafiltration using polymethylmethacrylate hemodiafilter.

Three times 3 hr/wk hemodiafiltration (simultaneous hemofiltration and dialysis: HDF) using Toray HDF system has been carried out on 4 patients. Filters used were Toray Filtryzers (membrane: polymethylmethacrylate, surface area 1.15 M2) with a dialysate flow of 500 ml/min. Nine to 10 L of body fluid was removed and 7-8 L of substitution fluid was reinfused distal to the filter (postdilution). Short-time HDF was favorable accepted by the patients. Blood pressure was stable, and disequilibrium syndrome negligible. Clinical courses as well as laboratory findings of the patients were satisfactory. The reduction rate of middle to larger molecules was 20 to 100% higher compared to conventional HD as measured by chromatogram. Loss of amino acids was about 3 gm/treatment. Reduction of hormones was negligible and no depletion syndrome was observed throughout the observation period up to 10 mos. Acidosis was corrected within 3-4 hrs. Elevated blood concentration of lactate and acetate gradually decreased to a pretreatment level within 2-3 hrs after termination of the procedure. Removal of middle molecules by HDF, in addition to removal of small molecules by conventional hemodialysis, is considered to be the treatment of choice for uremic patients.

Acrylic Resins↗
PubMed1977

Clinical experience with circumferentially reinforced expanded polytetrafluoroenthylene (E-PTFE) graft as a vascular access for haemodialysis.

Circumferentially reinforced E-PTFE grafts were implanted 50 times in 46 patients. Seven grafts became occluded during the observation period of 233 patient-months. Puncture and haemostasis were quite satisfactory in the majority of the patients. Histologically, the inner surface of the grafts was covered with a thin fibrin layer. Puncture sites were stuffed with fibro-fibrinous tissue preventing bleeding or aneurysmal dilatation. Clinical experience has proved the E-PTFE graft to be a suitable vascular prosthesis for blood access.

Adolescent↗
PubMed1976

Is hollow fibre occlusion due to maldistribution of blood?

Blood flow has been shown to be very slow in the central portion of a capillary bundle where intracapillary clotting mainly occurs. It is concluded that extremely uneven blood distribution is a causative factor in intracapillary clot formation in the HFAK examined.

Blood Coagulation↗
PubMed1975

Biodegradable material for bladder reconstruction.

The objective of this study was to develop a biodegradable material for use in reconstructive surgery of the bladder to serve a temporary function until normal regrowth of the host's tissue is completed. The biodegradable material can serve as a base over which the new bladder can regenerate. At the conclusion of the regrowth of the new tissue, the temporary material could be consumed by the body and therefore not have to be removed. Material evaluation showed that 70% acetic anhydride treated bovine pericardium was digested and dissolved in 4 weeks when implanted subcutaneously in dogs. Based upon this, supplementation of the bladder using this material was performed on 5 dogs. One dog showed urinary leakage and was sacrificed after 1 week. In 3 dogs examined 4, 6, and 48 weeks after implantation, respectively, the implanted material had been dissolved. In one animal autopsied at 10.5 months, a small remnant of the material still remained. Post-operative observation of the animals, excretory pyelocystograms and cystometry confirmed that the material applied was useful for experimental urinary bladder supplementation.

Acetates↗