Electrophysiological effect of adenosine triphosphate and adenosine on atrial and ventricular action potential duration in humans

Bolus injection of adenosine triphosphate (ATP) or adenosine is widely used clinically for terminating supraventricular tachycardia. However, bolus injection of these drugs has been reported to provoke atrial fibrillation (Afib). The effects of ATP and adenosine on the monophasic action potential duration (MAPD) of atrial and ventricular muscle was investigated, as well as the changes in the spatial distribution of atrial functional refractoriness caused by adenosine. Bolus injection of ATP and adenosine shortened atrial MAPD; no change was observed in the ventricle. Because local f-f intervals during atrial fibrillation correlate with the atrial refractory period, changes in mean f-f intervals in the right atrial appendage, His bundle region, coronary sinus ostium and distal coronary sinus were compared before and after injection of adenosine during induced Afib. Maximal shortening of f-f intervals was observed in the right atrial appendage. Inhomogeneous shortening of atrial refractoriness may account for the Afib following bolus injection of ATP or adenosine.     

Restricted usage of T-cell receptor alpha-chain variable region (TCRAV) and T-cell receptor beta-chain variable region (TCRBV) repertoires after human allogeneic haematopoietic transplantation

We analysed T-cell receptor alpha-chain variable region (TCRAV) and T-cell receptor beta-chain variable region (TCRBV) repertoires in peripheral blood mononuclear cells (PBMCs) from 34 recipients of allogeneic bone marrow transplantation (allo-BMT), seven of allogeneic peripheral blood stem cell transplantation and 19 of autologous peripheral blood stem cell transplantation using the quantitative microplate hybridization assay. TCR usage skewed at an early period (6-7 weeks) after BMT. The change was more apparent in allogeneic recipients than in autologous recipients. In particular, a predominant increase was detected in the frequency of VA1-4 (26%, 11 of 41 recipients), VA3-1 (32%) and VB24-1 (28%). Interestingly, acidic amino acid residues frequently followed the arginine residue in complementarity-determining region 3 of BV24S1. We further examined the extent of skew using samples obtained at serial time points after transplantation. The normalization of skewed repertoires occurred over a long period of time (> 8 years). There was a significant difference in the rate of normalization of skewed TCR repertoires between adult and child recipients (P < 0.05). The results suggest that these T cells may have expanded in response to allogeneic antigens, such as miHA (minor histocompatibility antigen), and that altered repertoires are eventually normalized by T-cell regeneration via a thymic-dependent pathway in children.     

Conjunctive effects of the 5HT(2) receptor antagonist, sarpogrelate, on thrombolysis with modified tissue plasminogen activator in different laser-induced thrombosis models

The effect of the serotonin (5HT(2)) receptor antagonist, sarpogrelate, was compared with that of the selective thrombin inhibitor, argatroban, in modified tissue plasminogen activator (mt-PA)-induced thrombolysis using two laser-induced thrombosis models reflecting different levels of vascular endothelial cell damage. Bolus intravenous infusions of mt-PA (0.1, 0.2, 0.4 mg/kg) induced thrombolysis in a dose-dependent manner. Sarpogrelate (4.7 mg/kg b.i. + 1.0 mg/kg/h i.v.) given together with mt-PA (0.2 mg/kg b.i.) optimally enhanced thrombolysis (p < 0.05) in a helium-neon laser-induced model where endothelial damage was minimal but not in an argon laser model where desquamation of endothelial cells was recognized. In contrast, argatroban (0.5 mg/kg b.i. + 0.1 mg/kg/h i.v.) given with mt-PA (0.2 mg/kg b.i.) significantly enhanced thrombolysis in both laser models. The findings indicate that the effectiveness of sarpogrelate in thrombolytic therapy might depend on the extent of vascular damage.     

The impact of visceral obesity on surgical outcomes of laparoscopic surgery for colon cancer

Purpose

Although obesity is considered as a risk factor for postoperative morbidity in abdominal surgery, its effect on the outcomes of laparoscopic-assisted colectomy (LAC) is still unclear. The technical difficulty and risk factor for postoperative complication in LAC are thought to be influenced by visceral obesity. The aim of this prospective study was to evaluate the impact of visceral fat on the surgical outcomes of LAC.

Methods

Between April 2005 and December 2010, consecutive patients with preoperatively diagnosed colon cancer, excluding medium and low rectal cancer, who underwent LAC, were enrolled. Their visceral fat area (VFA) and body mass index (BMI) were prospectively collected. The VFA was assessed by Fat Scan software. The patients were classified into two groups as follows: VFA nonobese with VFA <100 cm² (VNO) and VFA obese with VFA ≧100 cm² (VO). The predictive factors for surgical complications of LAC were evaluated by univariate and logistic regression analyses.

Results

A total of 338 consecutive patients were enrolled in this study. Of the 338 patients, 194 (57.4 %) and 138 (42.6 %) were classified into the VNO and VO groups, respectively. Logistic regression analysis showed that high BMI (≧25 kg/m²) and VO independently predicted the incidence of overall postoperative complications (p?=?0.040 and 0.007, respectively). VO was more highly related to the incidence of overall postoperative complications, anastomotic leakage (p?=?0.021), and surgical site infection (SSI) (p?=?0.013) than high BMI.

Conclusions

VFA is a more useful parameter than BMI in predicting surgical outcomes after LAC.     

Detection of HEY1‐NCOA2 fusion by fluorescence in‐situ hybridization in formalin‐fixed paraffin‐embedded tissues as a possible diagnostic tool for mesenchymal chondrosarcoma

Mesenchymal chondrosarcoma (MC) is an extremely rare subtype of chondrosarcoma. A tumor specific fusion gene, HEY1‐NCOA2 fusion, was recently identified in this tumor. The finding raises the possibility that the diagnosis of MC can be improved by examining the fusion gene. In the present study, we aimed to evaluate the efficacy of fluorescence in situ hybridization (FISH) in detecting HEY1‐NCOA2 fusion for the diagnosis of MC. Specimens from 10 patients diagnosed with MC were used for the study. Dual‐color FISH was performed using two different probes that specifically hybridize to HEY1 and NCOA2, respectively. Fusion signals were identified in all but two specimens, in which no signal was detected, presumably because of inadequate sample preparation. In accordance with results of a previous study, FISH analysis was highly sensitive in detecting HEY1‐NCOA2 fusion in adequately prepared MC samples. The current study adds further support for the use of HEY1‐NCOA2 fusion as a valid diagnostic marker for MC.     

Atrial natriuretic polypeptides: structure-activity relationship in the central action--a comparison of their antidipsogenic actions

The structure-activity relationship of atrial natriuretic polypeptides (ANPs) in the central action was investigated by examining the suppressive effects of the intracerebroventricular (i.c.v.) administration of ANPs on water intake induced by the i.c.v. injection of angiotensin II (AII) (0.1 nmol) in rats. alpha-Rat ANP (alpha-rANP), alpha-human ANP, alpha-rANP4-28 and alpha-rANP5-28 at a dose of 1.5 nmol exerted equipotent antidipsogenic actions, while alpha-rANP7-23-amide had no inhibitory effect on water drinking at this dose.