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Biomedical subjects

W J Kolff

Publications and source records attributed to W J Kolff.

At least 91 records · Page 5Linked to original sources
PubMed1978

Hypogeusia and zinc depletion in chronic dialysis patients.

Dialysis patients generally have a poor appetite, do not enjoy eating, and complain of food, particularly protein, as being disagreeable. Twenty dialysis patients with the above symptoms were tested for taste acuity, serum zinc (Zn), Zn concentrations in hair samples (intracellular Zn), and daily caloric intake. A double-blind, cross-over study was instituted using a Zn supplement and a placebo. After supplementation with Zn, taste acuity markedly improved in 95% of patients and Zn concentrations in hair increased in 85% of patients. The patients' appetites were improved; the average caloric intake increased by 675 kcal/day, and intolerance to protein diminished. In addition 10 normal control subjects were studied pre- and post-Zn supplementation for fasting blood glucose, serum Zn levels, and hair Zn concentration. Side effects were noted, and these usually correlated with elevated serum Zn levels and were minimized or disappeared with decrease in dosage or cessation of therapy.

Adult↗
PubMed1978

Scanning electron microscopic evaluation of the surfaces of artificial hearts.

This report summarizes the surface changes seen in artificial hearts implanted in calves for periods up to four months. Fabrication defects as well as degradation resulting from wear are identified. SEM evaluation of the blood contacting surface as well as the surface of the diaphragm associated with the drive mechanisms has revealed potential problems with current heart designs and methods of fabrication. Materials evaluation of implanted hearts is crucial for a clinically useful system to evolve.

Animals↗
PubMed1978

Transapical left ventricular bypass: a method for partial or total circulatory support.

A simple cannula method of partial or total left ventricular bypass, utilizing a roller pump and outflow filter, has been developed and applied clinically. One of three patients with severe cardiac and multisystem failure was pumped with total left ventricular bypass for six days and decannulated with recovery of myocardial function after nine days. These results are encouraging and suggest that a number of patients could be salvaged from temporary cardiac failure with a simple cannula-roller-pump bypass system.

Adult↗
PubMed1978

Combined technological-clinical approach to wearable dialysis.

To evaluate the constraints imposed upon the design of wearable dialysis systems, prototypes using currently available hardware were applied to three different dialysis formats: 1) the wearable artificial kidney (WAK) for hemodialysis (HD), 2) reciprocating peritoneal dialysis (RPD), and 3) alternating sorbent based dialysis/diafiltration(Ds/F) with a highflux membrane. 1) WAK dialysis has undergone extensive clinical trials with results comparable to standard HD. This system, including a self-contained power source, weighs 4.5 kg. The pulsatile blood flow can be disadvantageous, and cost of disposables is high. 2) RPD is shown to be an effective PD format, with the clearance of urea averaging 29.7 (23.9 to 41.5) ml/min in 14 patients, totalling 548 RPD dialyses. 3) After four conceptual trials, the Ds/F system was used for one treatment. Mass transfer results show removal of: urea nitrogen, 15.4 g; creatinine, 1.9 g; uric acid, 1.2 g; potassium, 89.2 mEq; and a positive bicarbonate balance of 94 mEq. The design constraints of these systems were elucidated, and prototype compact delivery systems have been constructed. It is concluded that a) non-mechanical PD wearability exists and b) true wearability of HD or Ds/F systems is not yet technologically feasible, but constraints are less rigid for Ds/F than for HD.

Biomedical Engineering↗
PubMed1978

The beat goes on: status of the artificial heart, 1977.

After two decades of continuous research on the artificial heart, survival times of experimental animals indicate that clinical application of such a device is definitely feasible. However, a number of problems remain to be solved. Durability of the device, infection, pannus formation at the interface between the device and natural tissue and thrombosis within the device appear to be the major problems. Development of an implantable power source is also an area of important research. Questions of efficiency, cosmetic and psychological acceptability and cost are just beginning to be considered.

Animals↗
PubMed1978

Prolonged, transapical left ventricular bypass (TALVB) in sheep and man.

Transapical left ventricular bypass has been demonstrated in normal sheep and one lamb. Recently, TALVB was applied in 3 clinical cases of cardiac failure, with recovery of myocardial function in one patient after 9 days of bypass (6 days total TALVB). These studies suggest that LV apical cannula-roller pump bypass with low dose heparin anticoagulation and secondary surgery to remove the cannula may salvage some patients now dying of temporary cardiac failure.

Adult↗
PubMed1977

Exponential growth and future of artificial organs.

One hundred thousand (100,000) people are living--thanks to Artificial Kidneys. We need more emphasis on Home Dialysis. The immediate future will bring us: WAK (Wearable Artificial Kidney) FAK (Filtrating Artificial Kidney) PAK (Peritoneal Artificial Kidney) HAK (Hemoperfusion Artificial Kidney). Intra-aortic balloon pumps and transapical left ventricular bypass may offer patients now dying from heart failure, a possibility to either recover or be maintained until an artificial heart is available. Our aim is to create an Artificial Heart to totally replace the irreparably sick human heart. We have obtained survival times up to more than six months after total replacement of the natural heart in calves. Dr. Steve Jacobsen's Artificial Arm is activated by electromyographic signals that are derived from the shoulder muscles. The Artificial Eye makes use of direct stimulation of the visual cortex of the brain by arrays of electrodes situated against the visual cortex. For the Artificial Ear, we stimulate the fibers of the eighth nerve by threading platinum wires up into the cochlea. Deaf volunteers can hear rhythm, loudness and some pitch.

Animals↗