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Biomedical subjects

R Bach

Publications and source records attributed to R Bach.

96 records · Page 6Linked to original sources
PubMed1977

Induction of spectrin in erythroleukemic cells transformed by Friend virus.

The presence and accumulation in murine erythroleukemic cells transformed by Friend virus of the erythrocyte membrane-associated protein spectrin has been investigated. Spectrin was present in the uninduced cells and was induced 10- to 20-fold in dimethyl sulfoxide-treated differentiating cells. The intracellular concentration of spectrin reached a peak on the third day of dimethyl sulfoxide treatment, after which it fell to levels found in mouse erythrocytes. We also found that the small subunit of spectrin was phosphorylated in the cells.

Animals↗
PubMedDate not supplied

[Torsion stability of coronary catheters].

In the present study, the torsional moments of 8 different types of catheter having two different calibres (n = 5 in each case) were investigated. The catheters were made of linear polyurethane (Cordis, Netherlands). The transmitted torsional moments of the 5.2 Fr. catheters positioned in a straight line were 1.48 +/- 0.09 Ncm (VK = 6%), positioned in a 90 degree curve 1.39 +/- 0.11 Ncm (VK = 8%). The corresponding figures for the 6 Fr. catheters were 2.43 +/- 0.20 Ncm (VK = 8%) and 2.26 +/- 0.20 Ncm (VK = 9%). The highly stable transmission behaviour in particular of the 5 Fr. catheters--with a variation coefficient of the torsional moments of 6%--is due mainly to the accurate manufacture of the catheters, and the material chosen. The study is a first step towards achieving systematic quality control of the materials used for diagnosis and therapy.

Cardiac Catheterization↗
PubMedDate not supplied

[The flow of contrast media in coronary catheters: study of the structural quality in interventional cardiology].

In the present study we investigated the contrast medium flow in 8 different types of left heart catheter having two different diameters (each n = 5). Using a 10 ml syringe and the contrast medium Ultravist 370, we calculated a mean value of 94.24 N + 16.01 for the maximum manual injection force in 18 test subjects. For the sake of simplicity, the figure of 100 N was defined as standardized manual force (which is within the standard deviation). If the maximally admissible static pressure of 82.5 bar is not to be exceeded, flow rates of not more than 16-17 ml/s are possible with 5.2 Fr. catheters, and 21-23 ml/s and 1.46 ml/s for 5.2 Fr. catheters, and between 1.99 ml/s and 2.17 ml/s for 6 Fr. catheters. Thus, a 50% higher flow can be achieved with 6 Fr. catheters as compared with 5.2 Fr. catheters at the same injection force. The iodine delivery rates are between 506 mg iodine/s and 539 mg iodine/s for 5.2 Fr. catheters, and between 738 mg iodine/s and 804 mg iodine/s for 6 Fr. catheters. The figures for the jet stream.

Cardiac Catheterization↗
PubMedDate not supplied

Haemocompatibility of endovascular coronary stents: Wiktor GX.

The stent to be examined (Wiktor-Stent, Medtronic ESTC, Kerkrade, NL) was mounted into a closed-loop tubular-system and perfused with platelet-rich plasma (PRP). As controls the tubular-system without stent (as non-thrombogenic control) and secondly the tube filled with glassbeads (as thrombogenic control) were evaluated. A decrease in the number of singularly circulating thrombocytes correlated well with an increases in circulating platelet aggregates. The increasing activation of thrombocytes was demonstrated by immunolabelling of surface structures (CD 62) which become prominent on activation of thrombocytes. The increase in case of the non-thrombogenic controls is thought to be due to the action of the roller-pump. This increase was coincident with an increase in immunologically labelled GPIIb/IIIa receptors and well correlated with an increase in platelet activation as demonstrated by the elevated CD 62 label. In spite of the use of anticoagulation principles in the perfusion model, thrombin was generated (measured by the TAT-complex) in all three cases and the completed coagulation (measured by the occurrence of fibrin D-dimers) also happened. The amount of D-dimers was small, however, in the cases of non-thrombogenic controls and of tubes equipped with stents. Only after the contact of PRP with tubes filled with glass-beads a significant increase in D-dimers followed. In conclusion the implantation of a stent led to an activation, adherence and aggregation of thrombocytes to a somewhat greater extent as in the control-system. It has, however, a much less thrombogenic surface than glass-beads.

Adult↗
PubMedDate not supplied

Walk training and drug treatment in patients with peripheral arterial occlusive disease stage II. A review.

On the basis of the present studies physical therapy is the most effective basis therapy of peripheral arterial occlusive disease stage II according to Fontaine. The consequent integration of the patients into widespread vascular training groups would be desirable. All present studies with so-called vasoactive drugs led to a statistically significant increase in pain-free walking distance. This is especially true for the substances naftidrofuryl, pentoxifylline, and buflomedil. Nevertheless, these studies do not fully meet the standards set by the GCP or the FDA guidelines. It must also be said that the increase in walking distance by vasoactive substances is less pronounced than the effect obtained by walk training alone. Both the vasoactive therapy and controlled walk training aim at an increase in pain-free walking distance. It is, however, still unclear whether the modes of therapy described influence the primary disease. Angiographically controlled studies are momentarily not available.

Arterial Occlusive Diseases↗