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Biomedical subjects

P Bucher

Publications and source records attributed to P Bucher.

At least 109 records · Page 6Linked to original sources

[Arteriosclerotic aneurysms of the right coronary artery in a 56-year-old female].

We report the case of a 56-year-old woman with a saccular aneurysm of the right coronary artery, which was resected. Aneurysmatic coronary artery disease mostly has an arteriosclerotic origin and occurs in patients with coronary artery disease with a frequency of 0.3-4.9%. In the affected patients myocardial infarction is more frequent, but their 5-year survival rate is not diminished. The therapy of choice is, as indicated, aortocoronary bypass grafting.

Aneurysm↗

Signal search analysis: a new method to localize and characterize functionally important DNA sequences.

The generation of "signal search data" represents a general method of describing the common properties of a set of DNA sequences presumed to be functionally analogous. Besides the detailed description of this method we present two computer programs which use signal search data as input data: One that processes them to a "constraint profile" and another one which lists over-represented "signals" of potential functional relevance. To illustrate the possibilities of our method we have analysed a set of transcription initiation sites of sea urchin histone genes.

Animals↗

Transcription of a cloned Xenopus laevis H4 histone gene in the homologous frog oocyte system depends on an evolutionary conserved sequence motif in the -50 region.

A cloned Xenopus laevis H4 histone gene has been expressed in the X.laevis oocyte nucleus. The homologous histone H4 gene can be correctly and efficiently expressed in the frog oocyte even in presence of bacterial vector DNA. As revealed by both analytical gel electrophoresis and S1 mapping, two H4 mRNAs are specified with different transcriptional efficiencies from the tandemly repeated promoter. Results from deletion mapping of the sequences essential for promoting H4 transcription show that drastic reduction of transcription is obtained when the sequences lying between -64 and -35 bp from the mRNA cap site are removed. We demonstrate by DNA sequence comparison using a novel computer program that this important area of the H4 promoter contains two highly conserved DNA motifs near positions -51 to -46 upstream from the cap site in all H4 gene promoters analysed.

Amino Acid Sequence↗

[Different determination of sinoatrial conduction time in patients with and without sinus node dysfunction].

Using intracardiac recordings of electrical activity and programmed electrical right atrial stimulation of the human heart, the sinoatrial conduction time (SACT) in the method of Strauss et al. 1973 (SACTc) was calculated in 80 patients with and without disturbances of rhythm and compared to the modified measurement of the SACT in the method reported by Narula et al. in 1978 (SACTN). The number of continuous stimuli variied from 4, 8 and 16 stimuli with a frequency of 10% just above the averaged spontaneous frequency. The best correlation was found between the SACTc and the SACTN16 (r = 0.74; p less than 0.001) with a regression line of: SACTN16 = 1.04 SACTc + 28.6. Under these conditions, as opposed to SACTN4 or SACTN8, the most favourable reproducibility and relative coefficient of variation (rVk) could be observed: SACTN16: rVk = 9.5%; r = 0.91; SACTN8: rVk = 12.3%; r = 0.89; SACTN4: rVk = 24.3%; r = 0.53. Higher individual values for SACTN16 were found by continuous atrial stimulation as compared to other methods of determination indicating mainly a higher depression of sinus node automaticity due to overdrive suppression. Under parasympathicolysis (1 mg atropine) the lowest values of SACT were found for SACTN4 (45.9 +/- 20.7 ms) coming closest the "true" SACT, since under these conditions neither an increase of the refractory period nor an overdrive suppression exert an influence.

Arrhythmias, Cardiac↗

Sea urchin histone mRNA termini are located in gene regions downstream from putative regulatory sequences.

S1 nuclease mapping of the Psammechinus miliaris embryonic histone mRNAs locates the 5' termini in or adjacent to a short sequence homology (5'pyCATTCpu3') downstream from the putative RNA polymerase II regulatory sequence (5'TATAAATA3') or related sequences. The 3' termini map just after a sequence containing GC-rich hyphenated dyad symmetry, a feature of most known terminator sequences.

Animals↗

Construction and function of a new hydraulic cuff occluder.

The construction of a new type of vascular cuff occluder for use in conscious animals is described. This occluder has the following features: 1. Safe complete vessel occlusion. 2. Occlusion at a definite cuff pressure with extrathoracally pressure control behind the cuff. 3. Long term implantability. 4. Possibility of multiple usage and sterilization.

Animals↗

Prophylaxis of ventricular fibrillation after acute experimental coronary occlusion by chronic beta-adrenoceptor blockade with atenolol.

Acute occlusions of the left circumflex coronary artery were performed in open-chest dogs. A control group (n = 19) was compared with three groups (total n = 17) pretreated once daily with different doses of the cardioselective beta-blocking drug atenolol (ICI 66 082) given by mouth for 5 days. Only animals without coronary collateral vessels were examined, having a mortality rate of 100% in the control group. Arrhythmias and ventricular fibrillation during the first 30 min after coronary occlusion showed a biphasic distribution in time (phase 1a and 1b). A lower degree of beta-adrenoceptor blockade reduced the incidence of arrhythmias and ventricular fibrillation in phase 1a, but fibrillation occurred in all animals during phase 1b. A higher dose of the beta-blocking drug protected the animals from ventricular fibrillation, and arrhythmias in phase 1a were greatly reduced. At all times the ventricular fibrillation threshold in the group pretreated with atenolol was significantly higher than in the control group. In both groups a significant decrease in ventricular fibrillation threshold was found only during phase 1a. The greater sensitivity of phase 1a arrhythmias to beta-blockade and the lack of a decrease in ventricular fibrillation threshold during phase 1b might indicate differences in the genesis of arrhythmias and fibrillation in phases 1a and 1b.

Animals↗

[Course and prognosis of reflux disease under conservative and surgical treatment].

Radiology, endoscopy and function tests were performed in 30 patients with primary reflux disease. Follow-up examinations were performed 3.2 +/- 1.5 years later. Esophagitis was more frequent in men. Severity of esophagitis correlated neither with the duration of symptoms before diagnosis nor with the results of function tests. Neither esophagitis nor function tests allowed a prediction on the long-term severity of symptoms. Episodic symptoms were more frequent in patients with esophagitis and constant symptoms more frequent in those without esophagitis. The indication for conservative and surgical treatment mainly depended on chance. Good therapeutic results were obtained in only 11 of 17 patients undergoing conservative treatment and in 9 of 13 patients undergoing surgical treatment. 6 patients of the surgical group had postfundoplication symptoms. Thus, the results of conservative and surgical treatment were quantitatively similar and rather disappointing.

Female↗

Different determination of sinoatrial conduction time (SACT) in man.

Using intracardiac recordings of electrical activity and programmed electrical right atrial stimulation of the human heart, the sinoatrial conduction time (SACT) in the method of Strauss et al. 1973 (SACTc) was calculated in 80 patients with and without disturbances of rhythm and compared to the modified measurement of the SACT in the method reported by Narula et al. in 1978 (SACTN). The number of continuously stimuli varied from 4, 8 and 16 stimuli with a frequency of 10% just above the averaged spontaneous frequency. The best correlation was found between the SACTc and the SACTN16 (r = 0.74; p less than 0.001) with a regression line of: SACTN16 = 1.04 SACTc + 28.6. Under these conditions, as opposed to SACTN4 or SACTN8, the most favourable reproducibility and relative coefficient of variation (rVk) could be observed: SACTN16: rVk = 9.5%; r = 0.91; SACTN8: rVK = 12.3%; r = 0.89; SACTN4: rvK = 24.3%; r = 0.53. Higher individual values for SACTN16 were found by continuous atrial stimulation as compared to other methods of determination indicating mainly a higher depression of sinus node automaticity due to overdrive suppression. Under parasympathicolysis (1 mg atropine) the lowest values of SACT were found for SACTN4 (45.9 +/- 20.7 ms) coming closest the "true" SACT, since these conditions neither an increase of the refractory period nor an overdrive suppression exert an influence.

Adult↗

[Diabetes Type I therapy through transplantation].

Diabetes is one of the most common chronic diseases in our society. While insulin treatment for diabetes type I could delay and reduce the incidence of diabetic complications, it is associated with an increased risk of severe hypoglycemia. To restore physiologic insulin metabolism, transplantation of insulin producing cells (pancreatic Beta cells) represent the sole available therapy. It could be done either through pancreas or islet of Langerhans transplantation. In this paper, we review actual knowledge regarding these two types of transplantations.

Diabetes Mellitus, Type 1↗