Electrophysiologic properties of atrial muscle in paroxysmal atrial fibrillation

The electrophysiologic properties of atrial muscle were studied by programmed atrial stimulation in 42 patients with paroxysmal atrial fibrillation (PAF) and in 53 control patients without PAF. Single premature atrial stimulation was given at the right atrial appendage following 8 basic stimuli with a basic cycle length of 500 ms. Repetitive atrial firing (RAF) was defined as the occurrence of 2 or more successive premature atrial activations following single premature atrial stimulation. Fragmented atrial activity (FAA) was defined as an increase by more than 75% of the duration of the atrial electrogram in response to a single premature stimulation. Interatrial conduction delay was defined as an increase of the conduction time by more than 50 ms in response to a single premature stimulation. RAF was induced in 26 of 42 patients (61.9%) with PAF and in 14 of 53 control patients (26A%). FAA and interatrial conduction delay were elicited in 69.0 and 80.9% of patients with PAF and in 34.0 and 56.6% of control patients, respectively. In 16 patients with PAF in whom RAF was not induced, FAA developed in 11 patients (68.8%). In 88.1% of 42 patients with PAF and in 41.5% of 53 controls, RAF or FAA, or both, were elicited by atrial premature stimulation. It is concluded that the incidence of RAF and FAA were significantly higher in patients with PAF than in the control group, and the induction of RAF or FAA, or both, was closely related to the vulnerability of the atrial muscle to atrial fibrillation.     

A survival case of acute mitral regurgitation and cardiogenic shock caused by subtotal occlusion of the first diagonal branch.

An 80-year-old woman was admitted with cardiogenic shock; she arrived in a deep coma with systolic blood pressure of 44 mmHg. An electrocardiogram showed ST elevation in I, aVL, V5 and V6, suggesting myocardial infarction in the lateral area of the left ventricle. A chest roentgenogram showed right pulmonary edema without cardiomegaly. Transthoracic and transesophageal echocardiograms revealed severe mitral regurgitation and a flailing anterior mitral valve leaflet, suggesting a ruptured papillary muscle. The patient was initially treated with high-dose dopamine, dobutamine and norepinephrine. Intraaortic balloon pumping was initiated after the patient's condition stabilized. She underwent emergency mitral valve replacement with a prosthetic valve. Complete rupture of the anterior papillary muscle was confirmed. Histological examination revealed necrosis of the anterior papillary muscle with inflammatory changes. She recovered uneventfully. Postoperative coronary angiography demonstrated subtotal occlusion of the first diagonal branch, and left ventriculography demonstrated akinesis of the lateral segment. This was a rare case in which subtotal occlusion of the first diagonal branch caused rupture of an anterior papillary muscle leading to severe mitral regurgitation.     

Recurrence of Helicobacter pylori infection and the long-term outcome of peptic ulcer after successful eradication in Japan.

Recurrence of peptic ulcer after successful eradication of Helicobacter pylori is closely associated with reinfection. The aim of this study was to examine the recurrence of peptic ulcer and reinfection with H. pylori after successful eradication. To eradicate H. pylori infection, patients with active peptic ulcer disease were assigned to two treatment groups depending on the year of their enrollment (AM group and OAMR group). Patients in the AM group received 400 mg of cimetidine twice per day, 300 mg of amoxicillin three times per day, and 250 mg of metronidazole three times per day for 2 weeks. Patients in the OAMR group received 20 mg of omeprazole once per day, 500 mg of amoxicillin granules three times per day, 250 mg of metronidazole three times per day, and 150 mg of roxithromycin twice per day for 1 week. After endoscopy verified ulcer scarring and successful eradication of H. pylori infection, study patients were followed up monthly and did not undergo acid-suppressive therapy. Endoscopy was performed at 6-month intervals for the 1st year. After the 1st year, follow-up endoscopies were performed annually. In total, 107 patients with peptic ulcer (duodenal ulcer [DU], 65; gastric ulcer [GU], 42) were followed up for a mean period of approximately 2 years. Recurrence of infection occurred in 10 (9.3%) of 107 patients (AM group, 9; OAMR group, 1) after 210 patient-years of follow-up; the recurrence rate was 4.8% per patient-year. Recurrence of H. pylori infection was significantly higher in the AM group (23.1%) than in the OAMR group (1.5%). H. pylori infection recurred in two patients 6 months after eradication therapy, in seven 1 year after, and in one 2 years after. Thereafter, no further cases of H. pylori recurrence were observed. During follow-up periods, seven cases of ulcer recurrence were observed (DU, 4; GU, 3). The rate of peptic ulcer recurrence within 2 years after eradication therapy was significantly higher than that after more than 2 years. Four cases of ulcer recurrence (DU, 3; GU, 1) also had recurrence of H. pylori infection. One recurrent case of DU without reinfection was associated with nonsteroidal anti-inflammatory drugs. The remaining two cases of GU recurred without H. pylori reinfection. In conclusion, peptic ulcer recurrence rarely occurred (3 [2.9%] of 103) in patients cured of H. pylori infection. Reinfection after apparent successful eradication was rarely noted when a powerful therapeutic regimen in eradication was used. Therefore, to eradicate H. pylori, a highly effective therapeutic regimen should always be used.     

Characterization of Mandibular Bones in Senile Osteoporotic Mice

At present, little is known about the age-related changes in jaw bones. The aim of this study was to characterize the mandibles of 6 month-old senile osteoporotic mice, SAMP6, and compare with those of age-matched controls, SAMR1. In comparison to SAMR1, SAMP6 showed thinner cortical bone, lower bone volume, and poorly organized collagen matrix. The collagen fibril diameter in SAMP6 was significantly smaller than that of SAMR1. In SAMP6 both collagen content and cross-links were lower than those of SAMR1, but the ratio of the major mature cross-link (pyridinoline) to its precursor reducible cross-link (dehydrodihydroxylysinonorleucine/its ketoamine) was higher in comparison to SAMR1. In addition, the extent of lysine hydroxylation of collagen was higher in SAMP6 than that of SAMR1. These results indicate that not only the quantity of collagen but also its quality are altered in SAMP6 and may result in the age-associated osteoporotic defects of mandibles.     

Substance P Activates p38 Mitogen-Activated Protein Kinase to Promote IL-6 Induction in Human Dental Pulp Fibroblasts

Substance P (SP) induces the expression of proinflammatory cytokines, such as interleukin (IL)-6, which are implicated in pulp inflammation. To determine the signal pathway of SP-induced IL-6, we examined the activities of the mitogen-activated protein kinases (MAPKs) in human dental pulp cell (PF-10) cultures. SP induced the phosphorylation of p38 MAPK within 5 min; this activation persisted for up to 40 min and was independent of the activation of extracellular signal-related kinases (ERK-1 and ERK-2) that were induced after SP stimulation of PF-10 cells. As shown by electrophoretic mobility shift assay p38 MAPK was not involved in SP-induced activation of nuclear factor-kappa B (NF-κB). However, p38 MAPK mediated SP-induced IL-6 production, as shown by the use of specific inhibitors of this kinase. Our results suggest that the activation of p38 MAPK is important for NF-κB-independent regulator of neurogenic inflammation in dental pulp tissues.     

Low-dose Interferon-α Treatment Improves Survival and Inflammatory Responses in a Mouse Model of Fulminant Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is accompanied by severe lung inflammation induced by various diseases. Despite the severity of symptoms, therapeutic strategies for this pathologic condition are still poorly developed. Interferon (IFN)-α is well known as an antiviral cytokine and low-dose IFN-α has been reported to show antiinflammatory effects. Therefore, we investigated how this cytokine affected ARDS in a mouse model. C57BL/6 mice received sequential intratracheal administration of α-galactosylceramide (α-GalCer) and lipopolysaccharide (LPS), which resulted in the development of fulminant ARDS. These mice were then treated intranasally with IFN-α and their survival, lung weight, pathological findings, and cytokine production were evaluated. Administration of low-dose IFN-α prolonged survival of fulminant ARDS mice, but higher doses of IFN-α did not. Histological analysis showed that low-dose IFN-α treatment improved findings of diffuse alveolar damage in fulminant ARDS mice, which was associated with reduction in the wet/dry (W/D) lung weight ratio. Furthermore, IFN-γ production in the lungs was significantly reduced in IFN-α-treated mice, compared with control mice, but tumor necrosis factor (TNF)-α production was almost equivalent for both groups. Low-dose IFN-α shows antiinflammatory and therapeutic effects in a mouse model of fulminant ARDS, and reduced production of IFN-γ in the lung may be involved in the beneficial effect of this treatment.     

Utility of bedside artificial pancreas for postoperative glycemic control in cardiac surgery

Journal of Artificial Organs - Perioperative hyperglycemia, hypoglycemia, and high glycemic variability are independent risk factors for mortality in critically ill patients. After cardiac surgery,...     

Numerical analysis of blood flow distribution in 4- and 3-branch vascular grafts

Trifurcated arch grafts (3-branch grafts) are now being used to repair the thoracic aorta in addition to conventional arch grafts (4-branch grafts). The anatomical shape of the 3-branch graft is different from the original vessel, so it is necessary for clinical application to evaluate blood flow distribution in the graft to assess whether there is adequate blood flow to the target organs. To achieve this, we developed a computational fluid dynamics (CFD) method to evaluate blood flow distribution in the grafts. Aortic blood flow was measured by phase-contrast magnetic resonance imaging (PC-MRI), and flow distribution into the branched vessels was obtained. The MRI image was used to create a patient-specific image model that represents the geometry of the aortic arch. The CFD analysis method was employed to determine a boundary condition of the blood flow analysis in the aorta using a patient-specific image model. We also created simplified models of 4-branch and 3-branch grafts and used our CFD analysis method to compare blood flow distribution among simplified models. It was found that blood flow distribution in the descending aorta was 71.3 % for the 4-branch graft and 67.7 % for the 3-branch graft, indicating that a sum of branching flow in the 3-branch graft was almost the same as the one in the 4-branch graft. Therefore, there is no major concern about implanting a new 3-branch graft. Our CFD analysis method may be applied to estimate blood flow distribution of a newly developed vascular graft prior to its clinical use and provide useful information for safe use of the graft.