Synthesis of the C-terminal half of thymosin α1 by the polymeric reagent method

In this report we further show the utility and efficiency of polymer-bound 1-hydroxybenzotriazole (PHBT) as an almost ideal support for the polymeric reagent method of peptide synthesis. This was demonstrated by the synthesis of thymosin α₁ (15–28), in which two suitably blocked segments, Boc-Asp (OtBu)-Leu-Lys (2Cz)-Glu (OBzl)-Lys (2Cz)-Lys (2Cz)-OH ( 3 ) and Boc-Glu (OBzl)-Val-Val-Glu (OBzl)-Glu (OBzl)-Ala-Glu (OBzl)-Asn-OBzl ( 2 ), were prepared entirely by utilizing PHBT activation for each coupling step. After appropriate deblocking of 2 , segments 2 and 3 were coupled by the DCC-HOBT method, followed by complete deblocking and ion-exchange chromatographic purification, affording the C-terminal half of thymosin α₁, H-Asp-Leu-Lys-Glu-Lys-Lys-Glu-Val-Val-Glu-Glu-Ala-Glu-Asn-OH ( 1 ).     

Ventriculoatrial Conduction Capability and Prevalence of 1:1 Retrograde Conduction During Inducible Sustained Monomorphic Ventricular Tacbycardia in 305 Implantable Cardioverter Defibrillator Recipients

Retrograde Conduction During Inducible Sustained Monomorphic Ventricular Tachycardia in 305 Implantable Cardioverter Defibrillator Recipients. Despite the advent of dual chamber ICDs, differentiation of VT (SMVT) with 1:1 VA conduction will remain a challenge. In this study, VA conduction capability and prevalence of inducible sustained monomorphic (SM) VT with 1:1 VA conduction was assessed in 305 ICD recipients. SMVT with a mean cycle length (CL) of 304 ± 61 ms was induced in 161 (53%) patients. Twenty-six percent of the patients maintained 1:1 VA conduction to CL ≤ 400 ms during incremental ventricular pacing, regardless of presenting tachyarrhythmia or presence of inducible SMVT. Among ten patients who had inducible SMVT with possible 1:1 VA conduction (based on SMVT CL comparable to the shortest CL associated with 1:1 retrograde conduction during ventricular pacing), all seven with available intracardiac tracings had documented 1 :1 VA conduction during the induced SMVT—representing 4.4% of the patients with inducible SMVT (95% CI 1.2%-7.6%), and 2.3% of the entire ICD cohort (95% CI 0.6%-4.0%). We conclude that about one-fifth of ICD recipients possess 1:1 VA conduction to CL ≤ 400 ms and that inducible SMVT with 1:1 VA conduction can be demonstrated in a small hut nonnegligible proportion of ICD recipients. These data are relevant to the design of tachyarrhythmia-discrimination algorithms for dual chamber ICDs.     

Laparoscopic treatment of colovesical fistulas: technique and review of the literature

Colovesical fistula is an uncommon complication of diverticulitis. We present our technique of a laparoscopic approach for treatment of vesicosigmoid fistulas and review the available published literature. We believe that a laparoscopic approach is a feasible and advantageous alternative for the treatment of colovesical fistulas, with low morbidity and short hospital stay.     

Examination of Left External and Internal Carotid Arteries During Transesophageal Echocardiography

The present study demonstrates the feasibility of delineating the carotid bulb and the proximal portions of the left external and left internal carotid arteries during transesophageal examination. This was accomplished by slowly and carefully withdrawing the probe from the esophagus into the pharynx.     

Incidence and Predictors of Left Atrial Thrombus Prior to Catheter Ablation of Atrial Fibrillation

Background: Transesophageal echocardiography (TEE) is commonly used prior to catheter ablation of atrial fibrillation (AF) in order to exclude left atrial (LA) thrombus. However, the incidence and predictors of LA thrombus detected with TEE have not been systematically examined in this setting.
Methods: This study included 732 cases (mean age 57 ± 11 years; 23% female; 353 persistent AF) in 585 consecutive patients referred for catheter ablation of AF. Patients were anticoagulated for at least 4 weeks prior to the procedure and then bridged with enoxaparin. TEE was performed in all cases within 24 hours prior to ablation.
Results: Preprocedural TEE revealed LA thrombus in 12 of 732 cases (1.6%), all located in the LA appendage. Among these 12 patients, 9 had persistent AF and 3 had paroxysmal AF. All patients with thrombus had an LA size ≥ 4.5 cm. LA thrombus was present in 0.3%, 1.4%, and 5.3% of patients with CHADS₂ scores of 0, 1, and ≥ 2, respectively. In multivariate analysis, a CHADS₂ score ≥ 2 and larger LA diameter remained significant predictors of LA thrombus.
Conclusions: Despite oral anticoagulation treatment, there is a small but significant incidence of LA thrombus by TEE prior to AF ablation. A CHADS₂ score ≥ 2 and larger LA diameter are independent predictors of LA thrombus in this patient population, while type of AF or rhythm at the time of TEE is not. The risk of LA thrombus is low in patients with a CHADS₂ score of 0 and in patients with an LA diameter < 4.5 cm.     

Analysis of High Frequency QRS Potential During Exercise Testing in Patients with Coronary Artery Disease and in Healthy Subjects

High resolution ECG waveforms from leads V₃, V₄, V₅, and V₆ were analyzed in two groups of male subjects before, during, and following treadmill exercise testing. Group A included 32 coronary artery disease (CAD) patients, with arteriographically proven > 75% obstruction of at least two main coronary arteries, and group B included 30 healthy subjects, without history or symptoms of CAD. Signal averaging and filtering techniques ware used in order to enhance the signal-to-noise ratio of the recorded ECG. The averaged QRS waveforms were filtered between 150 and 250 Hz. QRS complexes of the four leads were combined to form a “precordial average complex” (PAC). The PAC signals were examined for each subject at different stages of the exercise test and two parameters were computed: the root mean square (RMS) voltage; and the peak amplitude. The values of RMS and peak amplitudes measured at each stage of the exercise test were normalized to the values at rest. Normalized RMS (NRMS) values at peak exercise, immediately after peak exercise, and during the recovery phase were found to be higher for the healthy subjects than for the CAD group (1.17 ± 0.31 vs 0.94 ± 0.26, P < 0.008 at peak exercise, 1.13 ± 0.24 vs 0.84 ± 0.19, P < 0.001 after peak exercise, 1.08 ± 0.22 vs 0.94 ± 0.17, P < 0.007 during recovery). Cut-off NRMS value of one had a sensitivity of 81.3% and a specificity of 70.0% in differentiating CAD patients from healthy subjects in the examined groups. Normalized peak amplitude (NAMP) values exhibited similar behavior, with higher values for the healthy subjects than for the CAD group (1.23 ± 0.48 vs 0.94 ± 0.36, P < 0.03 at peak exercise, 1.20 ± 0.34 vs 0.83 ± 0.28, P < 0.001 after peak exercise, 1.10 ± 0.29 vs 0.94 ± 0.23, P < 0.02 during recovery). Specificity of 73.3% and sensitivity of 71.8% were found using a postpeak NAMP cut-off value of 1. In conclusion, the present study shows that using high frequency ECG may contribute to identifying patients with CAD. Further studies in larger groups of patients are required to better define the true predictive value of the method described for the diagnosis of CAD.     

ESTIMATION OF SERUM Vicfflb LIGHT CHAINS IN RHEUMATOID ARTHRITIS AND CORRELATION WITH CD5-POSITIVE -CELLS

The presence of Vidllb light chains in the sera of rheumatoidarthritis (RA) patients has been evaluated by an enzyme-linkedimmunosorbent assay (ELISA). VIIIb light chains have been confirmedto be largely restricted to IgM, and were rarely detected inthe IgG fraction of sera. The concentration of total serum VicIIIbdid not significantly vary with age, nor did it correlate withIgM-rheumatoid factor (RF) titre. Although total serumVIIIbwas not significantly increased in RA patients compared withmatched controls, IgM-RFs frequently contained VicIIIb. Usingflow cytometry, CD5-positive B-cells were not increased in theseRA patients compared with healthy laboratory control personnel.Furthermore, there was no direct correlation between total serumIgM VKlllb content and CD5-positive B-cell numbers in peripheralblood KEY WORDS: VkIIIb light chains, Rheumatoid factor (RF), CD5-positive B-cells, Rheumatoid arthritis