Use of Only a Regular Diagnostic His-Bundle Catheter for Both Fast and Reproducible "Para-Hisian Pacing" and Stable Right Ventricular Pacing

Pacing from the Diagnostic His-Bundle Catheter. Introduction : Para-Hisian pacing, i.e., pacing the anteroseptal right ventricle (RV) with or without direct capture of the His bundle (HB), allows the differentiation of VA conduction over the AV node from conduction over an accessory pathway. Classically, it is performed by maneuvering a separate pacing catheter around the HB catheter, which may be difficult and time-consuming.
Methods and Results : This study prospectively evaluated the use of a single standard octapolar HB catheter with 2-mm interelectrode spacing for simultaneous (para-Hisian) pacing from the distal bipole and recording from the three proximal bipoles in 148 consecutive patients. Para-Hisian pacing was successful in 146 of 148 patients, performed within a median of only 10 seconds, and easily repeated several times during the course of an electrophysiologic study. Retrograde HB activation could he recorded in 132 of 146 patients; a clearly different surface ECG configuration confirmed the presence or absence of HB capture in all other patients. Interestingly, stable RV pacing could he performed from the HB catheter for the rest of the electrophysiologic study in 138 of 142 patients in whom this was tried. RV pacing from this site also led to better interpretation of retrograde conduction, due to clear visualization of retrograde HB activation.
Conclusion : Pacing from the distal dipole of a regular diagnostic HB catheter provides a fast and reliable way to perform para-Hisian pacing. Therefore, it may be advocated as a routine diagnostic protocol during electrophysiologic procedures. Moreover, pacing from this site obviates the need for a separate RV pacing catheter in most patients.     

Long-Term Follow-Up of Corridor Operation for Lone Atrial Fibrillation:

Late Results of Surgery for AF. Introduction: Currently, surgery- and catheter-mediated ablation is applied when drug refractoriness of atrial fibrillation is evident, although little is known about the long-term incidence of new atrial arrhythmia and the preservation of sinus node function.
Methods and Results: To address this issue, 30 patients with successful corridor surgery for lone paroxysmal atrial fibrillation and normal preoperative sinus node function were followed in a single outpatient department. Five years after surgery, the actuarial proportion of patients with recurrence of atrial fibrillation arising in the corridor was 8%± 5%, with new atrial arrhythmias consisting of atrial flutter and atrial tachycardia in the corridor 27%± 8%, and with incompetent sinus node requiring pacing therapy 13%± 6%. Right atrial transport was preserved in 69% of the patients without recurrence of atrial fibrillation and normal sinus node function. Stroke was documented in two patients.
Conclusions: Corridor surgery for atrial fibrillation is a transient or palliative treatment instead of a definitive therapy for drug refractory atrial fibrillation. This observation strongly affects patient selection for this intervention and constitutes a word of caution for other, non-pharmacologic interventions for drug refractory atrial fibrillation.     

α-Amino acids derived from ornithine as building blocks for peptide synthesis

Recently great interest has arisen in the synthesis of combinatorial libraries, and this technology provides a significant partner to contemporary strategies in rational design and lead discovery. By simple combination of a given set of building blocks, high numbers of different molecules are produced simultaneously, increasing the possibility of discovery of a lead compound in a limited time. One direction of research in this field focuses on the synthesis of libraries composed of modified amino acids. Here, the synthesis and characteristics of some building blocks derived from ornithine are described. The synthesis is based on the acylation/sulfonation of the copper complex of ornithine by aroyl and arylsulfonyl chlorides exemplified by 2-thiophenecarbonyl chloride, p-toluenesulfonyl chloride and 8-quinolinesulfonyl chloride. To evaluate the potential use of these modified α-amino acids as component in an oligopeptide library, all three derivatives were incorporated in a hexapeptide with a random sequence using a standard coupling procedure (DIC/HOBt/DIEA). Depending upon the acidity of the amido hydrogen on the δ-nitrogen, competition between intramolecular cyclization and peptide bond formation was observed. The higher the acidity, the more pronounced is this side reaction. Coupling conditions for peptide formation were optimized so that the newly described amino acid based building blocks are suitable for incorporation into libraries consisting of unnatural amino acids. The outlined procedures open up a broad avenue of possibilities for creation of diversity into peptidic libraries.     

PREPARATION OF RACEMIC 2r-CARBOXY-TRANS,TRANS-3, 4-DIDEUTERO-PYRROLIDINE (DL-TRANS,TRANS-3, 4-DIDEUTERO-PROLINE) AND UNAMBIGUOUS ASSIGNMENT OF PROTONS IN THE 1H N.M.R. SPECTRUM OF PROLINE

Racemic trans, trans-3,4-dideutero proline has been prepared by catalytic deuteration of 3-pyrroline-2-carboxylic acid. The stereospecificity of the reduction (i.e. trans to the carboxylic group) was ascertained after transformation of the dideutero compound into the diketopiperazide c/Pro, Aib/, for which unambiguous proton assignments in the ¹H n.m.r. spectrum had been obtained previously. The identification of the configuration of the dideutero-proline allows for the affirmation of the correctness of proton assignments as previously proposed in literature.     

Functionally inactive apolipoprotein E3 in a type III hyperlipoproteinaemic patient

Abstract. Type III hyperlipoproteinaemia (HLP) is, amongst others, characterized by the E_2/2 phenotype as determined by isoelectric focusing of apolipoprotein E. However, one of our clinically symptomatic type III HLP patients showed a E_3/3 phenotype.
After complexation with phospholipid vesicles, apo E from this patient was, in contrast with apo E from a type IV HLP patient (E_3/4 phenotype), unable to compete with low density lipoprotein (LDL) for binding to the specific LDL receptors on cultured human fibroblasts. This defect in binding to the LDL receptor was not due to an impaired lipid binding capability. The clinical symptomatic type III hyperlipoproteinaemia of our patient is probably due to a functionally inactive apo E₃.     

Replacement of the anterior cruciate ligament with a coated carbon fibre prosthesis: a biomechanical study in goats

Anterior cruciate ligament replacement was performed in goats to evaluate a coated carbon fibre prosthesis. Anatomical placement of the implant was performed using either the prosthesis alone or the prosthesis augmented with soft tissue. Animals were assessed 13 and 52 weeks after surgery. Mechanical testing of the bone-ligament-bone complex was used to determine the failure load and the mode of failure. Both types of implant failed by prosthesis slippage at the femoral fixation site. Failure loads were significantly higher for augmented repairs than for plain carbon repairs at both 13 and 52 weeks. Augmentation of the prosthesis with patellar tendon and fascia lata enhanced the fixation strength of the implant.     

Operating theatre related syncope in medical students: a cross sectional study

Background  

Observing surgical procedures is a beneficial educational experience for medical students during their surgical placements. Anecdotal evidence suggests that operating theatre related syncope may have detrimental effects on students' views of this. Our study examines the frequency and causes of such syncope, together with effects on career intentions, and practical steps to avoid its occurrence.