Variet?ten des Brustbeines

Ohne ZusammenfassungMit 12 Abbildungen im Text und 6 Figuren auf den Tafeln 3/6.     

Smoking and coffee intake following alcohol withdrawal in alcoholic inpatients

The aim of this study was to assess alcoholic inpatients' smoking and coffee intake variation following withdrawal. Only moderate smokers (less than 30 cigarettes/day) showed a significant increase of cigarette consumption after alcohol withdrawal. However, their urinary cotinine level did not vary, suggesting a behavioral, and not biological, compensation through smoking following alcohol withdrawal. Heavy smokers (30 cigarettes/day or more) showed no significant clinical or biological variation of smoking behavior. Coffee consumption increased after alcohol withdrawal in all patients, irrespective of smoking habits.     

Paramecium calcium channels are blocked by a family of calmodulin antagonists.

Although the voltage-sensitive Ca channel present in Paramecium has been subjected to detailed physiological and genetic analysis, no organic ligands have been described that block this channel with high affinity and that ultimately can be used to identify channel components. Based on a previous observation that the naphthalene sulfonamide calmodulin antagonist W-7 can block Paramecium Ca channels at high concentration, we have synthesized analogs of W-7 that block these channels at concentrations of less than 1 microM. The effectiveness of these compounds was tested both by a sensitive behavioral assay and on Ca channels that had been incorporated into planar lipid bilayers. Despite the fact that these compounds are effective Paramecium calmodulin antagonists, two independent lines of evidence suggest that W-7 and its analogs block the Ca channel by a mechanism that is independent of their action on calmodulin. In addition, the sensitivity to W-7 or dihydropyridines of Ca channels present in a number of eukaryotic phyla has been used to identify similarities in Ca channels from widely diverse organisms. It appears that the pharmacological specificity provides a means to group Ca channels.     

Validation in the sheep of an ultrasound velocity dilution technique for haemodialysis graft flow

BACKGROUND: A simple, rapid, inexpensive method for measuring the flow in a patient's vascular access would permit routine monitoring during haemodialysis, and hence provide information of access graft deterioration sufficiently early to increase the success of minimally invasive remedial procedures. This paper reports the validation of such a method in animals. METHODS: A PTFE graft was implanted in sheep between the carotid artery and the jugular vein. While the sheep was under general anaesthesia and on an haemodialysis circuit, ultrasound velocity in its blood was perturbed by the injection of a 5-10 ml bolus of isotonic NaCl. The pump tubing flow was measured by a transit-time blood flow meter. This flow was combined with the areas of perturbation generated by the injection before and after mixing in the access flow to estimate graft flow. The calculated graft flow was compared to flow measured directly by a transit-time probe on the same carotid artery. RESULTS: Over a 10-fold range, 120-1260 ml/min, graft flow measured by ultrasound velocity dilution agreed well with graft flow measured directly with a scatter of 76 ml/min about the regression line. CONCLUSION: Ultrasound velocity dilution provides a method for measuring flow in the graft accurate enough for clinical evaluation of patients on dialysis.      

Regional differences in calcium-release channels from heart.

The heart is a heterogeneous tissue composed of several cell types tailored for specialized functions. We found that intracellular channels also exhibit regional specialization. In cardiac and skeletal muscle these channels are called the calcium-release channel and are identified by activation with either calcium or caffeine and inhibition by the hexavalent cation ruthenium red. The calcium-release channel of the sarcoplasmic reticulum from the interventricular septum has a smaller conductance (31 pS vs. 100 pS) and has longer open and closed times when compared with the channel from left-ventricular free wall. An additional calcium-permeable channel with an even smaller conductance (17 pS) was found in the septum, and this channel is similar to the inositol 1,4,5-trisphosphate-gated channel from smooth muscle and different from the calcium-release channel (ryanodine receptor) from skeletal and cardiac muscle. The inositol 1,4,5-trisphosphate-activated channel may be derived from specialized conducting tissue that is relatively abundant in the septum, whereas the other calcium-release channels may be derived from regionally specialized myocardial cells in the septum and free wall.