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Biomedical subjects

G W Kammlott

Publications and source records attributed to G W Kammlott.

9 recordsLinked to original sources
PubMed1975

Thromboresistance of glass after glow discharge treatment in argon.

Glow discharge treated (GDT) inorganic materials are sterile and free of all organic contaminants. Such materials implanted in the canine inferior vena cava often demonstrate significant thromboresistance. Standard Pyrex glass tubing was GDT in argon to provide a surface free energy above 70 dynes/cm, slight surface negativity, and other surface-physical modifications of its interface. Chromic acid cleaned lengths of the same tubing, and short segments whose edges were not fire-polished were used as controls. Upon canine implantation, the in vivo results were similar in independent surgical laboratories. The glass was implanted as 1.4 cm long rings or as 5 cm long tubes in separate medical centers according to different protocols. GDT specimens remained patent; all controls accumulated thrombi. A remarkably pure, low critical surface tension, labile protein coating covered all cylindrical lumens after 2 hr in vivo. This coating diminished within 2 weeks and was essentially absent after 480 days, eeven though scanning EM showed evidence of a micron thick luminal film, probably eroding glass. No emboli were found in the implant animal's kidney or lungs at any stage.

Animals↗
PubMed1975

Nonthrombogenic ac polarized copper prosthesis.

In previous studies from our laboratories, it was shown that metals and alloys which register negative potentials in blood vs the normal hydrogen electrode tend to be antithrombogenic while those with positive potentials are invariably thrombogenic. The present paper deals with a novel approach of maintaining an implanted metallic prosthesis at a negative potential. A copper vascular prosthesis in a dog was maintained at cathodic potentials by a small amplitude (+/- 10 mV) high-frequency ac (100 kHz) on the prosthesis. The prostheses were removed after 2 hours, 6 hours, 1 day, and 42 days, with subsequent visual and scanning electron microscopic examination of the prostheses completed. All tubes were free of thrombus deposits. Minimal junctional thrombi were found, probably due to differences in physicochemical characteristics of the vascular prostheses and recipient vessels. The results are compared with those in the control group (copper tubes with no current) and dc polarized copper tubes. While the control tubes occluded in 2 to 6 hours, the dc and ac polarized tubes remained patent. Of the ac and dc polarized tubes, the former tubes lasted up to 6 weeks with less thrombus deposit. The mechanism of operation of the ac polarized copper prosthesis is not fully understood.

Animals↗
PubMedDate not supplied

A comparative study of several polymers for use as intravenous catheters.

The widespread use of long-term intravenous catheters has produced some concern on the part of the clinician with respect to morbidity and occasional mortality associated with their use. Fourteen polymer surfaces were evaluated in experimental animals in this study. Several of the materials are commercially available; the others are experimental. In all, 160 catheters were placed in the femoral and jugular veins through side branches. The catheters were evaluated in terms of thrombosis, phlebitis, and periphlebitis, using an arbitary grading system. Scanning electron microscopy and light microscopy were employed to document the results. The most successful catheter materials were next evaluated in man, using the same experimental parameters. It is our belief that the observed thrombosis associated with morbidity is largely due to the surface characteristics of the catheter materials. These characteristics are largely surface phenomena related to the interactions between the tissue and catheter material. In this study, we have attempted to determine whether there are any significant differences in thrombogenicity and/or long-term function between the several currently available catheters. Based on this study, ethylene acrylic acid appears to be the most nonthrombogenic surface of the material tested.

Animals↗