Second Annual CMDC Conference, on the Theme of Environment-compatible Energy-sources, held at the Hotel Zürich, Zürich, Switzerland, during 10-12 December 1990

PAS 1109,EE 1108 PHYSIC

Isolated aortic valve replacement with the Björk-Shiley tilting disc prosthesis and the porcine bioprosthesis

Between 1977 and 1978, 239 patients underwent aortic valve replacement with either a bioprosthesis (100, BIO) or a Björk-Shiley tilling disc prosthesis (139, BS). Early mortality was 2%, late mortality 4%. There was no statistically significant difference between the two groups. Anticoagulation was maintained indefinitively in patients with a BS, after implantation of a BIO only for three months except in the presence of atrial fibrillation or a history ofeinboli. Thromboembolic complications and anticoagulant hemorrhages were almost twice as frequent in patients with BS than with BIO (5.3 versus 2.8 episodes/100 patient years). This difference however is statistically not significant. There were an equal number (two) of reoperations because of paravalvular leaks due to endocarditis or torn sutures in the two groups. A regurgitant murmur, though hemodynamically not significant, occurred more frequently in patients with BIO than with BS (10% versus 2%, P < 0.05). Its cause and importance cannot yet be determined. Postoperative results judged by the NYHA classification and reduction of heart size were similar in both groups. Of all patients, 13% with preoperative valvular incompetence and 15% with stenosis showed little or no reduction of the cardiothoracic ratio on X-ray indicating a worse long-term prognosis. The porcine BIO has become our preferred valvular substitute because of its low thromboembolic complication rate. The BS is mainly reserved for patients already on anticoagulants for other reaso

RNA elements directing in vivo assembly of the 7SK/MePCE/Larp7 transcriptional regulatory snRNP

Through controlling the nuclear level of active positive transcription elongation factor b (P-TEFb), the 7SK small nuclear RNA (snRNA) functions as a key regulator of RNA polymerase II transcription. Together with hexamethylene bisacetamide-inducible proteins 1/2 (HEXIM1/2), the 7SK snRNA sequesters P-TEFb into transcriptionally inactive ribonucleoprotein (RNP). In response to transcriptional stimulation, the 7SK/HEXIM/P-TEFb RNP releases P-TEFb to promote polymerase II-mediated messenger RNA synthesis. Besides transiently associating with HEXIM1/2 and P-TEFb, the 7SK snRNA stably interacts with the La-related protein 7 (Larp7) and the methylphosphate capping enzyme (MePCE). In this study, we used in vivo RNA-protein interaction assays to determine the sequence and structural elements of human 7SK snRNA directing assembly of the 7SK/MePCE/Larp7 core snRNP. MePCE interacts with the short 5'-terminal G1-U4/U106-G111 helix-tail motif and Larp7 binds to the 3'-terminal hairpin and the following U-rich tail of 7SK. The overall RNA structure and some particular nucleotides provide the information for specific binding of MePCE and Larp7. We also demonstrate that binding of Larp7 to 7SK is a prerequisite for in vivo recruitment of P-TEFb, indicating that besides providing stability for 7SK, Larp7 directly participates in P-TEFb regulation. Our results provide further explanation for the frequently observed link between Larp7 mutations and cancer development

Algometry with a clothes peg compared to an electronic pressure algometer: a randomized cross-sectional study in pain patients

<p>Abstract</p> <p>Background</p> <p>Hypersensitivity of the central nervous system is widely present in pain patients and recognized as one of the determinants of chronic pain and disability. Electronic pressure algometry is often used to explore aspects of central hypersensitivity. We hypothesized that a simple pain provocation test with a clothes peg provides information on pain sensitivity that compares meaningfully to that obtained by a well-established electronic pressure algometer. "Clinically meaningful" was defined as a medium (r = 0.3-0.5) or high (r > 0.5) correlation coefficient according to Cohen's conventions.</p> <p>Methods</p> <p>We tested 157 in-patients with different pain types. A calibrated clothes peg was applied for 10 seconds and patients rated the pain intensity on a 0 to 10 numerical rating scale. Pressure pain detection threshold (PPdt) and pressure pain tolerance threshold (PPtt) were measured with a standard electronic algometer. Both methods were performed on both middle fingers and ear lobes. In a subgroup of 47 patients repeatability (test-retest reliability) was calculated.</p> <p>Results</p> <p>Clothes peg values correlated with PPdt values for finger testing with r = -0.54 and for earlobe testing with r = -0.55 (all p-values < 0.001). Clothes peg values also correlated with PPtt values for finger testing with r = -0.55 (p < 0.001). Test-retest reliability (repeatability) showed equally stable results for clothes peg algometry and the electronic algometer (all r-values > 0.89, all p-values < 0.001).</p> <p>Conclusions</p> <p>Information on pain sensitivity provided by a calibrated clothes peg and an established algometer correlate at a clinically meaningful level.</p

A natural Finsler--Laplace operator

We give a new definition of a Laplace operator for Finsler metric as an average with regard to an angle measure of the second directional derivatives. This definition uses a dynamical approach due to Foulon that does not require the use of connections nor local coordinates. We show using 1-parameter families of Katok--Ziller metrics that this Finsler--Laplace operator admits explicit representations and computations of spectral data.Comment: 25 pages, v2: minor modifications, changed the introductio