[Initial experience of catheter ablation of ventricular tachycardia originate from endocardium via direct ventricle puncture access in patients underwent mechanical valve implantation].

Objective: To evaluate the results of catheter ablation of ventricular tachycardia (VT) via direct ventricle puncture access in patients without traditional approach. Methods: Two idiopathic left fasicular VT patients with mechanical aortic and mitrial valve repalcement and 1 patient with right ventricular originated VT post mechanical tricuspid valve repalcement from March 2010 to July 2012 in Fuwai hospital were enrolled in this study. For left fasicular VT patients, catheter ablation was performed using transapical left ventricular access via minithoracotomy. For the patient with right ventricular originated VT, catheter ablation was performed via percutaneous right ventricle puncture at xiphoid. Abaltion was guided under EnSite NavX mapping system. The feasibility of VT ablation via direct ventricle puncture access and long-term VT recurrence were investigated. Results: Catheter ablation was successful in all patients, and all clinical VTs were eliminated. The procedure time was 53, 62 and 74 minutes respectively with radiation time 11, 16 and 20 minutes. The ablation time was 130, 170 and 240 seconds individually. No procedure related complication occurred. After a follow-up time of 76, 55 and 82 months respectively, no VT recurrence was found in patients with left fasicular VT. New-onset VT with different morphology with previous VT was recorded in the patient with right ventricular originated VT, subcutaneous implantable defibrillator was implanted finally in this patient. Conclusions: For patients with endocardial origined ventricular arrhythmias which could not be ablated via traditional approaches, direct ventricle puncture access with hybrid techniques provides a new approach foreliminating VTs in these patients.

T cell-associated α4ß7 but not α4ß1 integrin is required for the induction and perpetuation of chronic colitis.

Anti-adhesion therapies that target α(4) integrins (e.g., natalizumab) are thought to work by blocking T-cell recruitment to the intestinal tissues in patients with Crohn's disease (CD); however, little direct evidence is available to confirm this contention. We wished to evaluate the importance of T cell-associated α(4) integrins in a chronic colitis model in mice and to determine the effect of natalizumab treatment on intestinal tissue T-cell accumulation in human CD. Adoptive transfer of T cells lacking α(4) (α(4)(-/-)) but not ß(1) integrin into immunodeficient mice produced significantly attenuated disease. This was correlated with reduced numbers of colon CD4 T cells compared with the control mice; however, tissue distribution of T helper type 1 (Th1) and T helper type 17 (Th17) cells and regulatory T cells (Tregs) was not affected by the lack of α(4). Furthermore, α(4)(-/-) T cells demonstrated defective homing to the chronically inflamed small intestines and colons. Finally, patients treated with natalizumab showed significant reduction in mucosal CD4 T cells and no skewing in the foxp3(+) Treg or T-bet(+)Th1 fractions thereof. These results demonstrate a direct role for T cell-associated α(4)ß(7) but not α(4)ß(1) integrins during initiation and perpetuation of chronic colitis. Moreover, our data demonstrated that natalizumab treatment reduced mucosal CD4 T-cell accumulation in CD patients.

Differential Colonization of Tomato Roots by Nonpathogenic and Pathogenic Fusarium oxysporum Strains May Influence Fusarium Wilt Control.

ABSTRACT Histochemical staining, beta-glucuronidase (GUS) activity, or placing roots on agar were methods used to characterize interactions between the pathogenic fungus, Fusarium oxysporum f. sp. lycopersici, and the nonpathogenic biocontrol F. oxysporum strain 70T01 with respect to colonization behaviors, interaction sites, and population densities on tomato roots. Mycelia of strain 70T01, a genetic transformant expressing stable GUS activity, hygromycin B resistance, and effective disease control, were localized in epidermal and cortex cell layers of tomato roots in a discontinuous and uneven pattern. In contrast, mycelia of F. oxysporum f. sp. lycopersici were found in the vascular bundles. Thus, direct interactions between the two fungi likely happen in the root surface cell layers. Colonization density of strain 70T01 was related to the inoculation density but decreased with distance from the inoculation site. Host defense reactions, including increased cell wall thickness or papilla deposits, were adjacent to 70T01 hyphae. Experiments done in soil showed that strain 70T01 densities in roots were highest at inoculation zones and barely detectable for root segments more than 2 cm away from the inoculation sites. F. oxysporum f. sp. lycopersici densities were lowest at 70T01 inoculation zones and highest (>10 times) where strain 70T01 was not directly applied. Newly elongating roots where strain 70T01 did not reach were available for infection by the pathogen. The higher strain 70T01 density was always found when the plants were simultaneously infected by F. oxysporum f. sp. lycopersici, suggesting that F. oxysporum f. sp. lycopersici has as much influence in predisposing the plant to colonization by strain 70T01 as strain 70T01 has on providing disease protection against the pathogen.

Biological function of modified nucleotides in tRNA molecules--synthesis and biological activity of the analogues of yeast alanyl tRNA with I34 replaced by A34 or G34.

Analogues of yeast alanyl tRNA with I34 replaced by A34 or G34 were synthesized. Synthetic analogues of yeast alanyl tRNT occupy the same position as the natural yeast alanyl tRNA on polyacrylamide gel electrophoresis, and their purity is about 95% after electrophoresis on a 10% or 20% polyacrylamide gel. The two terminal and nearest neighbour nucleotides of the analogues are all correct. The accepting activity of the synthetic analogues is similar to that of the reconstituted natural yeast alanyl tRNA. The incorporation activity of alanine into proteins of the synthetic analogues is about 30% of that of the natural of reconstituted natural yeast alanyl tRNA when I34 is replaced by A, and is 90% when I34 is replaced by G. The reason of the variation in biological function of the analogues of yeast alanyl tRNA after I34 replaced by A or G was discussed.

Effect of the anticodon loop size of yeast alanyl tRNA on its biological activity.

Three analogs of yeast alanyl tRNA with anticodon loops of different sizes, tRNA75 (no G35 and 5'-terminal phosphate), tRNA77 (one more C between G35 and C36, no 5'-terminal phosphate), and ptRNA79 (with Cm1I psi between G35 and C36), were synthesized. In comparison with the reconstituted natural yeast tRNA, the charging activities of the three analogs were 90% (tRNA75), 94.7% (tRNA77), and 104% (ptRNA79). These results supported the conclusion (Yang De-ping and Wang De-bao (T. P. Wang) (1983) Acta Biochim. Biophys. Sin. 15, 83-90) that the anticodon loop of yeast alanyl tRNA was not involved in the interaction between alanyl-tRNA synthetase from rat liver and yeast alanyl tRNA. In contrast, in the rabbit reticulocyte lysate system, the incorporation of alanine in the charged analogs was 0% (tRNA75 and ptRNA79) and 100% (tRNA77). There were significant differences between the incorporation activities of analogs and those of the reconstituted molecule. The reason for these differences is discussed.

Assay of biological activity of synthetic yeast alanine transfer RNA (tRNAAlay).

The biological activity of the synthetic tRNAAlay was studied with an extremely sensitive method. tRNAAlay accepted alanine in the presence of rat liver aminoacyl-tRNAAlay-synthetase (this was called the accepting activity). The aminoacylated tRNAAlay was conveniently precipitated by ethanol with good recovery. The efficiency of transferring alanine from the aminoacylated tRNAAlay into the protein was determined in in vitro rabbit reticulocyte lysate cell-free protein-synthesizing system (this was called the incorporation activity). Both accepting and incorporation activities could be determined in one assay with only 5-7 pmoles of tRNAAlay either in ligation mixture or in purified form. Our results show that the accepting activities of the synthetic products were 51.6-65.6% and 91.3-106.0% of that of natural and reconstituted natural tRNAAlay respectively. The efficiency of the incorporation of alanine in the aminoacylated tRNAAlay into the protein was 61.6-63.1%, corresponding to 90.6-91.7% and 97.2-115.8% of that of the natural and the reconstituted natural tRNAAlay respectively.