The present study aimed to understand the biofilm formation mechanism of Propionibacterium acnes by analyzing the components and structure of the biofilms. P. acnes strains were isolated from the surface of explanted cardiac pacemaker devices that exhibited no clinical signs of infection. Culture tests using a simple stamp culture method (pressing pacemakers against the surface of agar plates) revealed frequent P. acnes colonization on the surface of cardiac pacemaker devices. P. acnes was isolated from 7/31 devices, and the isolates were categorized by multilocus sequence typing into five different sequence types (STs): ST4 (JK18.2), ST53 (JK17.1), ST69 (JK12.2 and JK13.1), ST124 (JK5.3), ST125 (JK6.2), and unknown ST (JK19.3). An in vitro biofilm formation assay using microtiter plates demonstrated that 5/7 isolates formed biofilms. Inhibitory effects of DNase I and proteinase K on biofilm formation varied among isolates. In contrast, dispersin B showed no inhibitory activity against all isolates. Three-dimensional live/dead imaging of P. acnes biofilms with different biochemical properties using confocal laser microscopy demonstrated different distributions and proportions of living and dead cells. Additionally, it was suggested that extracellular DNA (eDNA) plays a role in the formation of biofilms containing living cells. Ultrastructural analysis of P. acnes biofilms using a transmission electron microscope and atmospheric scanning electron microscope revealed leakage of cytoplasmic components along with cell lysis and fibrous structures of eDNA connecting cells. In conclusion, the biochemical properties and structures of the biofilms differed among P. acnes isolates. These findings may provide clues for establishing countermeasures against biofilm-associated infection by P. acnes.

Reperfusion with leukocyte-depleted hypoxemic blood has a protective effect against ischemia/reperfusion-induced pulmonary dysfunction by reducing endothelial damage, cytokine release, and leukocyte activation.

Total cavopulmonary connection with use of an autogenous intraatrial tunnel to create a straight tube between the inferior vena cava and the pulmonary artery was attempted in several types of cardiac anomaly in eight consecutive candidates for the Fontan operation. A small right atrium with an extraordinary location of the inferior vena cava and a short superior vena cava prevented the use of this procedure in two cases. By preserving the crista terminalis and the sinus node and its arteries we prevented the development of postoperative atrial arrhythmias in the short follow-up period, and the P trigger-signal averaged P waves were not different from those of other cardiac anomalies. The proximal stump of the superior vena cava was not incised in any case to enlarge the anastomosis, even when size mismatch between the superior and inferior venae cavae existed, as in a case of bilateral superior venae cavae. Stretching the vessels by approximately 150% was possible and permitted an adequate anastomosis. Cavopulmonary connections via the intraatrial tunnel ensured smooth, nonturbulent, somewhat pulsatile flow without a pressure gradient. We concluded that the creation of an autogenous intraatrial tunnel was possible in many cases without serious complications and that this procedure has potential benefit for the pulmonary circulation in the aspect of pulsatility.

Left ventricular pseudoaneurysm is a rare, but potentially fatal, condition that generally occurs as a complication of myocardial infarction, infective endocarditis, or cardiac surgery. Surgical repair is the treatment of first choice because of the marked risk of rupture, but deteriorated hemodynamics and complicated procedures to treat the pseudoaneurysm may lead to a high mortality rate. We report a 62-year-old woman with a large left ventricular pseudoaneurysm after mitral valve replacement for rheumatic mitral valve stenosis. Surgical repair was not performed due to the patient's refusal, but her pseudoaneurysm resolved spontaneously by 2 years after mitral valve replacement. Spontaneous obliteration of a large left ventricular pseudoaneurysm is very rare in a patient on warfarin therapy. This case suggests that a left ventricular pseudoaneurysm with a narrow neck may resolve spontaneously in rare settings.

We concluded that TWBCP with olprinone reduces myocardial reperfusion injury by reducing oxidant-mediated lipid peroxidation, and it accelerates prompt and persistent LV functional recovery with suppression of reperfusion arrhythmia.