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Biomedical subjects

K A Rosenbauer

Publications and source records attributed to K A Rosenbauer.

At least 19 recordsLinked to original sources
PubMed1989

[Occlusal surfaces of glass-ceramic (Dicor) and VMK-crowns compared by electron scanning microscopy].

The surface of painted and unpainted glass ceramic-crowns (DICOR) was compared with that of ceramometallic-crowns by the means of the Scanning Electron Microscope (SEM). If handled correctly and accurately glass ceramic presents a superiorly surface-quality. A disadvantage is the great thickness of the paint, that forces to make a compromise in the occlusal region: here we should prefer the advantage of the possibility to make a correct occlusal relation to the antagonist tooth with wax-pattern to a homogenous smooth surface. Ceramometallic crowns should get a real glazing finish and we have to set value on a correct modelation of the frame and an optimal veneer at the crown margin.

Ceramics↗
PubMed1988

Extracorporeal CO2-removal with a heparin coated artificial lung.

Treatment of severe acute respiratory failure with extracorporeal gas exchange necessitating near complete systemic anticoagulation requires a delicate balance to be maintained between disseminated intravascular coagulation and hemorrhagic complications. The present study describes our first experience using a heparin coated extracorporeal artificial lung and circuitry during clinical extracorporeal CO2 removal. In spite of a partial thromboplastin time and activated clotting time within or close to the normal range, neither laboratory evidence for disseminated intravascular coagulation induced by the extracorporeal circuit nor thrombi in the pulmonary vasculature were found. Scanning electron microscopy of the heparin coated hollow fiber gas exchanger demonstrated only minor deposits on the surface. Use of a heparin coated artificial lung may enhance the margin of safety of extracorporeal gas exchange and ultimately broaden its indications.

Acute Disease↗
PubMed1982

Light microscopic and scanning electron microscopic findings on intravenous polyurethane catheters.

Tips of two different types of unused and used intravenous polyurethane catheters as well as heads of the corresponding needles for venipuncture, artificially cut surfaces and longitudinally cut parts were either directly mounted on stubs or previously fixed in 1% phosphate buffered glutaraldehyde, postfixed in 1% phosphate buffered osmiumtetroxyde (pH 7.4), dehydrated with acidified 2,2-Dimethoxypropane, dried in a critical point drying apparatus using CO2, mounted with silver paint on stubs and sputter coated with 15 nm gold. In general, the surface of polyurethane catheters is smoother than that of catheters manufactured out of other materials. Distance marks, when placed on the surface and parts of the catheter wall, containing radio-opaque admixtures show a very irregular arranged structure. It could be demonstrated, that these parts of the catheter wall as well as roughnesses, caused by the manufacturing process, are much more favourable for adhesion of formed elements of the blood and bacteria or spores than other areas of the wall. In addition occasionally extensive fibrin layers and contamination of the surfaces by denaturated plasma proteins were observed. For better compatibility and for prevention of endothelial lesions some advice is given to the manufacturers and the medical staff.

Bacteria↗
PubMed1981

Surface morphology and tensile force at breaking point or different kinds of intravenous catheters before and after usage.

Heads of seven different types of unused and used intravenous catheters as well as tips of the corresponding needles for venipuncture, artificially cut and ruptured surfaces were either directly mounted on stubs or previously fixed in 1% phosphate buffered glutaraldehyde (pH 7.4), dehydrated with acidified 2, 2-dimethoxy-propane, dried in a critical point drying apparatus using CO2, mounted with silver-paint and sputter coated with 20 nm gold. In addition tensile tests of unused catheters were carried out. According to the tensile tests and to the SEM findings neither spontaneous breakage nor manufacturing defects may be reason of catheter embolism. Manufacturing defects at the tips of needles for venipuncture, as well as rough surfaces of the introducers or catheter walls may cause endothelial lesions. Settling of formed elements of the blood apparently is related to ruggedness of the catheter wall or to manufacturing defects. Thrombi, grown on he outer surface of the catheters are very rare. In Cavafix catheters thrombus formation is mostly related to the roughness of radio-opaque parts of the catheter wall. Outgrowth of the thrombus via the top to the outer surface could be demonstrated frequently

Biomechanical Phenomena↗
PubMed1980

[Light and scanning electron studies on the morphology of the vaginal plug in laboratory animals].

Serial sections of vaginal plugs of mice, rats, guinea pigs and hamsters (Cricetulus griseus) were studied by light microscopy as well as whole plugs and freeze-fractures by scanning electron microscopy. The vaginal plugs are encircled by a layer of superficial cells of the vaginal epithelium and consist of coagulated seminal fluid, containing irregular holes. The spermatoza are mainly localized inside bigger cavities. Scanning electron microscopic study of freeze-fractured plugs reveals, that this method gives useful information about the inner structure of spermatozoa tails.

Animals↗
PubMed1980

[Preparation technique for SEM demonstration of the muscular system of the blood vessels and the granular juxtaglomerular cell complex in the kidney (author's transl)].

A technique for SEM demonstration as well of the muscular architecture in the media of the blood vessels, as the granular juxtaglomerular cell complex in the wall of the afferent arterioles in the kidney is described. This method consists in an incomplete maceration and washing process in vascular cast preparations.

Animals↗