Biomedical subjects

Kazuki Okamura

Publications and source records attributed to Kazuki Okamura.

5 recordsLinked to original sources

PubMed2006

Cardioprotective effects of recombinant human erythropoietin in rats with experimental autoimmune myocarditis.

Erythropoietin (EPO) has been known to have cytoprotective effects on several types of tissues, presumably through modulation of apoptosis and inflammation. The effect of EPO on myocardial inflammation, however, has not yet been clarified. We investigated the cardioprotective effects of EPO in rats with experimental autoimmune myocarditis (EAM). Seven-week-old Lewis rats immunized with cardiac myosin were treated either with EPO or vehicle and were examined on day 22. EPO attenuated the functional and histological severity of EAM along with suppression of mRNAs of tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 in the hearts as well as a reduction of apoptotic cardiomyocytes. The EPO receptor (EPO-R) was upregulated in the myocardium of EAM compared with that of healthy rats. These results may suggest that EPO ameliorated the progression of EAM by modulating myocardial inflammation and apoptosis.

Animals↗

PubMed2006

Decrease in amplitude of intracardiac ventricular electrogram and inappropriate therapy in patients with an implantable cardioverter defibrillator.

Intracardiac electrograms are important for discrimination of tachyarrhythmia by implantable cardioverter defibrillators (ICD). A low R-wave can cause not only undersensing of ventricular tachyarrhythmia but also inappropriate discharges due to oversensing of unexpected signals because of its characteristic sensing algorithm. Therefore, this study aimed to investigate adverse events associated with R-wave amplitude. We included 115 consecutive patients followed-up over one year after implantation of a transvenous ICD system. The status of the ICD was checked every 3 months and intracardiac ventricular electrograms were analyzed. The decrease in R-wave amplitude was high in arrhythmogenic hypertrophy cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy (ARVC), and sarcoidosis. Low R-waves (< 5.0 mV) were observed in 13 patients at a follow-up of 15 +/- 16 months after implantation, and the mean R-wave was 3.0 +/- 0.8 mV. The frequency of low R-waves was high in ARVC (38%), sarcoidosis (33%), and dilated cardiomyopathy (17%). All of the dilated cardiomyopathy patients with low R-waves had severe left ventricular dysfunction. Inappropriate ICD therapy resulting from T-wave oversensing occurred in 7 patients and the R-wave was < 5.0 mV in 6 of the patients. The frequency of inappropriate therapy was high in patients with sarcoidosis. In 3 patients, inappropriate therapy caused ventricular tachyarrhythmia. In conclusion, decreases in R-wave amplitude occurred in some progressive cardiac disorders and caused inappropriate ICD discharges having arrhythmogenicity. Physicians should attempt to obtain a high R-wave amplitude during ICD implantation and careful follow-up is required, especially in patients with ARVC or sarcoidosis.

Adult↗

PubMed2005

Elimination of late potentials by quinidine in a patient with Brugada syndrome.

The beneficial effects of quinidine on ST-segment elevation, inducible ventricular tachyarrhythmias, and episodes of ventricular tachyarrhythmia have been reported in Brugada syndrome. This is the first report describing quinidine-induced elimination of the late potential, which is considered one of the parameters for an arrhythmic event, in a patient with Brugada syndrome.

Anti-Arrhythmia Agents↗

PubMed2005

Ventricular fibrillation in two cases with dilated cardiomyopathy and mechanical alternans.

Clinical implication of mechanical alternans is yet unclear. It may suggest the risk for sudden death in patients with chronic heart failure. Two cases with dilated cardiomyopathy showed mechanical alternans during diagnostic cardiac catheterization. They suddenly died due to ventricular fibrillation before the induction of beta-blocker therapy. Patients with mechanical alternans should be treated under intense monitoring until the induction of beta-blocker therapy.

Adult↗

PubMed2004

A rare case of Graves' disease during regular hemodialysis.

We report a case of Graves' disease in a patient on regular hemodialysis. The patient also suffered from Wolff-Parkinson-White (WPW) syndrome and paroxysmal atrial fibrillation, which may both have been manifestations of the Graves' disease because of the increased oxygen demand. To our knowledge, this is the first case to illustrate the usefulness of the antithyroid agent propylthiouracil for Graves' disease complicated by endstage renal disease (ESRD) and WPW syndrome.

Antithyroid Agents↗