There is increasing interest in the bidirectional communication between the mammalian host and prokaryotic cells. Catecholamines (CA), candidate molecules for such communication, are presumed to play an important role in the gut lumen; however, available evidence is limited because of the lack of actual data about luminal CA. This study evaluated luminal CA levels in the gastrointestinal tract and elucidated the involvement of gut microbiota in the generation of luminal CA by comparing the findings among specific pathogen-free mice (SPF-M), germ-free mice (GF-M), and gnotobiotic mice. Substantial levels of free dopamine and norepinephrine were identified in the gut lumen of SPF-M. The free CA levels in the gut lumen were lower in GF-M than in SPF-M. The majority of CA was a biologically active, free form in SPF-M, whereas it was a biologically inactive, conjugated form in GF-M. The association of GF-M with either Clostridium species or SPF fecal flora, both of which have abundant β-glucuronidase activity, resulted in the drastic elevation of free CA. The inoculation of E. coli strain into GF-M induced a substantial amount of free CA, but the inoculation of its mutant strain deficient in the β-glucuronidase gene did not. The intraluminal administration of DA increased colonic water absorption in an in vivo ligated loop model of SPF-M, thus suggesting that luminal DA plays a role as a proabsorptive modulator of water transport in the colon. These results indicate that gut microbiota play a critical role in the generation of free CA in the gut lumen.

ong QT syndrome (LQTS) is a rare disease characterized by prolonged ventricular repolarization and a high risk for cardiac events including sudden cardiac death. 1 Mutations causing LQTS have been identified in 5 genes, each encoding a cardiac ion channel and its regulatory subunit. [2][3][4][5] Most cases of LQTS that come to the attention of physicians are either symptomatic or familial. [6][7][8] Recent studies have reported that life-threatening arrhythmias in LQTS patients tend to occur under specific circumstances (eg, exercise, emotion, and sleep/rest without arousal) in a gene-specific manner. 9 Beta-blocker therapy is reported to be effective in preventing LQTS-related cardiac events in these patients, but they continue to occur while patients are on the prescribed medication. 10 A recent report has reported a gender reference in the electrocardiographic (ECG) response to -blockers in patients with LQTS. 11 A screening program conducted for Japanese children (1st, 7th and 10th grades) has uncovered large numbers of children with LQTS both without a family history and without a history of LQTS-related cardiac events at the Circulation Journal Vol.67, December 2003 time of diagnosis. 12-14 The initiation of drug therapy for these young patients is controversial because many pediatric cardiologists consider that few young LQTS patients without a past history have experienced new cardiac events after diagnosis. The objective of the present study, then, was to examine the characteristics of Japanese pediatric patients with LQTS and to determine the predictive factors for cardiac events after diagnosis in these young patients with and without a past history of cardiac events. Methods Subjects and DataA questionnaire was sent to 111 hospitals where the trustee(s) of the Japanese Society of Pediatric Cardiology and Cardiac Surgery were working. Subjects were those who visited one of those hospitals from January 1997 to August 2000 and who were less than 20 years old at the time of diagnosis. Characteristics of the subjects obtained from the survey included the following: past history of LQTS-related cardiac events, ECG findings, clinical and family history for diagnosis of LQTS according to the criteria of Schwartz et al, 15 cardiac events during the period after diagnosis and medication. When medication was prescribed, those patients were re-surveyed for compliance. Subjects were classified into 2 groups on the basis of the presence or absence of a past history of LQTS-related cardiac events at the time of diagnosis. The index events for diagnosis were classified as follows: (1) Who Is at Risk for Cardiac Events in Young PatientsWith Long QT Syndrome?Masao Yoshinaga, MD*; Masami Nagashima, MD; Toshimitsu Shibata, MD; Ichiro Niimura, MD; Mitsuo Kitada, MD; Toshiaki Yasuda, MD; Mari Iwamoto, MD; Junko Kamimura, MD; Mayu Iino, MD; Hitoshi Horigome, MD; Masashi Seguchi, MD; Sumi Aiba, MD; Naomi Izumida, MD; Takashi Kimura, MD; Hiroya Ushinohama, MD; Junichiro Nishi, MD*; Yukiharu Kono, MD*; Yuichi Nomura, MD*; Ko...

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Introduction It is important to consider recurrent arrhythmia after catheter ablation for persistent atrial fibrillation (AF) for planning an ablation strategy. However, the studies are limited to pulmonary vein isolation (PVI) plus posterior wall isolation (PWI), which were reported to improve procedural outcomes. The objective of this study is to evaluate the effect of PWI on recurrent arrhythmia. Methods This is an observational study on patients with persistent AF comparing PVI plus PWI and PVI only strategies. In PVI plus PWI group, linear ablation of the left atrium roofline and bottom line were performed to achieve PWI after PVI. Some patients with AF recurrence underwent the second procedure. The presence of recurrent arrhythmia and results of the second procedures were evaluated. Results A total of 181 patients (mean age, 66.9 ± 10.2 years; male, 76.8%) were included. PVI plus PWI group and PVI only group consisted of 90 and 91 patients, respectively. AF recurrence was observed in 28 of 90 (31.1%) patients with PVI plus PWI and in 43 of 91 (47.3%) with PVI only, and log‐rank test did not show any significant difference (p = .35). The occurrence of recurrent persistent AF was significantly lower in PVI plus PWI group than in PVI only group (5/90; 5.6% vs. 18/91; 20.9%, p = .002). There was no significant difference between the two groups in recurrent paroxysmal AF and atrial tachycardia (AT). Conclusion PWI, in addition to PVI, for persistent AF was significantly related to fewer episodes of recurrent persistent AF, and it did not increase recurrent AT.