Clinical characteristics and analysis of prognostic factors in methicillin-resistant Staphylococcus aureus endocarditis: A retrospective multicenter study in Japan.

BACKGROUND: Infective endocarditis (IE) caused by MRSA (methicillin-resistant Staphylococcus aureus) is associated with a high mortality rate. This study aimed to elucidate the characteristics of patients with MRSA-IE in Japan and identify the factors associated with prognosis. METHODS: This retrospective study included patients with a confirmed diagnosis of IE caused by MRSA, between January 2015 and April 2019. RESULTS: A total of 65 patients from 19 centers were included, with a mean age of 67 years and 26 % were female. Fifty percent of the patients with IE were had nosocomial infections and 25 % had prosthetic valve involvement. The most common comorbidities were hemodialysis (20 %) and diabetes (20 %). Congestive heart failure was present in 86 % of patients (NYHA class I, II: 48 %; III, IV: 38 %). The 30-day and in-hospital mortality rates were 29 % and 46 %, respectively. Multi-organ failure was the primary cause of death, accounting for 43 % of all causes of death. Prognostic factors for in-hospital mortality were age, disseminated intravascular coagulation, daptomycin and/or linezolid as initial antibiotic therapy, and surgery. Surgical treatment was associated with a lower mortality rate (odds ratio [OR], 0.026; 95 % confidence interval [CI], 0.002-0.382; p = 0.008 for 30-day mortality and OR, 0.130; 95 % CI; 0.029-0.584; p = 0.008 for in-hospital mortality). CONCLUSION: Mortality due to MRSA-IE remains high. Surgical treatment is a significant prognostic predictor of MRSA-IE.

Antimicrobial therapy and outcome of methicillin-resistant Staphylococcus aureus endocarditis: A retrospective multicenter study in Japan.

BACKGROUND: MRSA (methicillin-resistant Staphylococcus aureus)-infective endocarditis (IE) is associated with high morbidity and mortality. This study aimed to assess data from patients with MRSA-IE across multiple facilities in Japan, with a specific focus on antimicrobial therapy and prognosis. METHODS: This retrospective study enrolled patients with a confirmed diagnosis of IE attributed to MRSA, spanning the period from January 2015 to April 2019. RESULTS: Sixty-four patients from 19 centers were included, with a median age of 67 years. The overall mortality rate was 28.1% at 30 days, with an in-hospital mortality of 45.3%. The most frequently chosen initial anti-MRSA agents were glycopeptide in 67.2% of cases. Daptomycin and linezolid were selected as initial therapy in 23.4% and 17.2% of cases, respectively. Approximately 40% of all patients underwent medication changes due to difficulty in controlling infection or drug-related side effects. Significant prognostic factors by multivariable analysis were DIC for 30-day mortality and surgical treatment for 30-day and in-hospital mortality. For vancomycin as initial monotherapy, there was a trend toward a worse prognosis for 30-day and in-hospital mortality (OR, 6.29; 95%CI, 1.00-39.65; p = 0.050, OR, 3.61; 95%CI, 0.93-14.00; p = 0.064). Regarding the choice of initial antibiotic therapy, statistical analysis did not show significant differences in prognosis. CONCLUSION: Glycopeptide and daptomycin were the preferred antibiotics for the initial therapy of MRSA-IE. Antimicrobial regimens were changed for various reasons. Prognosis was not significantly affected by choice of antibiotic therapy (glycopeptide, daptomycin, linezolid), but further studies are needed to determine which antimicrobials are optimal as first-line agents.

Nationwide surveillance of bacterial respiratory pathogens conducted by the surveillance committee of the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2019-2020: General view of the pathogens' antibacterial susceptibility.

The trends and prevalence of antimicrobial susceptibility of pathogens vary by country, region, and time. Long-term regular surveillance is required to investigate trends in the antimicrobial resistance of various isolated bacterial pathogens. We report the results of a nationwide surveillance on the antimicrobial susceptibility of bacterial respiratory pathogens in Japan conducted by the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology. The isolates were collected from clinical specimens obtained from adult patients who visited a collaborating medical facility between June 2019 and December 2020 and were diagnosed with respiratory tract infections by a physician. Antimicrobial susceptibility testing was performed in a centralized laboratory according to the methods recommended by the Clinical and Laboratory Standards Institute. Susceptibility testing was performed for 932 strains (201 Staphylococcus aureus, 158 Streptococcus pneumoniae, 6 S. pyogenes, 136 Haemophilus influenzae, 127 Moraxella catarrhalis, 141 Klebsiella pneumoniae, and 163 Pseudomonas aeruginosa) collected from 32 facilities in Japan. The proportions of methicillin-resistant S. aureus and penicillin-resistant S. pneumoniae were 35.3% and 0%, respectively. In H. influenzae, 16.2% and 16.9% were ß-lactamase-producing ampicillin resistant and ß-lactamase-negative ampicillin resistant, respectively. Extended-spectrum ß-lactamase-producing K. pneumoniae accounted for 5.0% of all K. pneumoniae infections. Carbapenemase-producing K. pneumoniae and multi-drug-resistant P. aeruginosa with metallo-ß-lactamase were not detected in this study. This surveillance will be a useful reference for treating respiratory infections in Japan and will provide evidence to enhance the appropriate use of antimicrobial agents.

Multiple Cardiovascular Diseases or Risk Factors Increase the Severity of Coronavirus Disease 2019.

BACKGROUND: This study aimed to determine whether disease severity varied according to whether coronavirus disease 2019 (COVID-19) patients had multiple or single cardiovascular diseases and risk factors (CVDRFs).Methods and Results:COVID-19 patients with single (n=281) or multiple (n=412) CVDRFs were included retrospectively. Multivariable logistic regression showed no significant difference in the risk of in-hospital death between groups, but patients with multiple CVDRFs had a significantly higher risk of acute respiratory distress syndrome (odds ratio: 1.75, 95% confidence interval: 1.09-2.81). CONCLUSIONS: COVID-19 patients with multiple CVDRFs have a higher risk of complications than those with a single CDVRF.

Evaluation of SARS-CoV-2 RNA quantification by RT-LAMP compared to RT-qPCR.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) is a global pandemic caused by a novel virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The viral load of SARS-CoV-2 is associated with mortality in COVID-19 patients. Measurement of viral load requires the use of reverse transcription quantitative PCR (RT-qPCR), which in turn requires advanced equipment and techniques. In this study, we aimed to evaluate the viral load measurement using reverse transcription loop-mediated isothermal amplification (RT-LAMP), which is a simpler procedure compared to RT-qPCR. MATERIALS AND METHODS: RNA was extracted by using the QIAamp Viral RNA Mini Kit. The RT-LAMP assay was performed by using the Loopamp® 2019-SARS-CoV-2 detection reagent kit and 10-fold serial dilutions of known viral load RT-LAMP were used to measure Tt, which is the time until the turbidity exceeds the threshold. Based on the relationship between viral load and Tt, the linearity and detection sensitivity of the calibration curve were evaluated. In addition, 117 clinical specimens were measured, and RT-qPCR and RT-LAMP assay results were compared. RESULTS: The dilution linearity of the calibration curve was maintained at five orders of magnitude 1.0× 106 to 1.0 × 101 copies/µL, and was confirmed to be detectable down to 1.0 × 100 copies/µL. The limit of quantification of RNA extracted from clinical specimens using RT-LAMP correlated well with that obtained using RT-qPCR (r2 = 0.930). CONCLUSION: The findings indicate that RT-LAMP is an effective method to determine the viral load of SARS-CoV-2.

Observational study to determine the optimal dose of daptomycin based on pharmacokinetic/pharmacodynamic analysis.

High doses of daptomycin (DAP) (>6 mg/kg/day) have been preliminarily recommended in recent practical guidelines for methicillin-resistant Staphylococcus aureus infection, to achieve better clinical effects. While such doses can elevate the plasma trough concentration (Cmin) of DAP, there is an associated risk of creatine phosphokinase (CPK) elevation warranting further investigation. In the current study relationships between DAP Cmin and CPK elevation were investigated, and optimal DAP doses were determined. Plasma DAP concentrations were measured in 20 patients. Logistic regression analysis was performed to assess relationships between DAP Cmin and CPK elevation, then a population pharmacokinetic model of DAP was developed. To determine an optimal DAP dose a Monte Carlo simulation (MCS) was performed to minimize the risk of CPK elevation and maximize the probability of successful treatment. In logistic regression analysis DAP Cmin was significantly associated with CPK elevation (odds ratio 1.21, p = 0.048). With respect to dose-dependent increases in the probability of CPK elevation and exposure to DAP, MCS estimated an optimal DAP dose of 4-6 mg/kg/day, corresponding to a minimum inhibitory concentration (MIC) of ≤0.5 µg/mL. For an MIC of 1 µg/mL, MCS estimated an optimal DAP dose of 10 mg/kg/day. However, the probability of CPK elevation associated with high doses of DAP was higher than that associated with the approved doses. In cases where high doses of DAP are administered, close CPK monitoring is required and therapeutic drug monitoring of DAP may be desirable.

Nationwide surveillance of bacterial respiratory pathogens conducted by the surveillance committee of japanese society of chemotherapy, the japanese association for infectious diseases, and the japanese society for clinical microbiology in 2016: General view of the pathogens' antibacterial susceptibility.

The nationwide surveillance on antimicrobial susceptibility of bacterial respiratory pathogens from the patients in Japan was conducted by the Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2016. The isolates were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections during the period between February 2016 and August 2016 by three societies. Antimicrobial susceptibility testing was conducted at the central reference laboratory according to the method recommended by Clinical Laboratory Standards Institute. Susceptibility testing was evaluated in 1062 strains (143 Staphylococcus aureus, 210 Streptococcus pneumoniae, 17 Streptococcus pyogenes, 248 Haemophilus influenzae, 151 Moraxella catarrhalis, 134 Klebsiella pneumoniae, and 159 Pseudomonas aeruginosa). Ratio of methicillin-resistant S. aureus was 48.3%, and those of penicillin-susceptible S. pneumoniae was 99.5%. Among H. influenzae, 14.1% of them were found to be ß-lactamase-producing ampicillin-resistant strains, and 41.1% to be ß-lactamase-non-producing ampicillin-resistant strains. Extended spectrum ß-lactamase-producing K. pneumoniae and multi-drug resistant P. aeruginosa with metallo ß-lactamase were 4.5% and 0.6%, respectively.

Risk factors for ventilator-associated pneumonia in neonatal intensive care unit patients.

Ventilator-associated pneumonia (VAP) is a serious complication in neonatal patients on mechanical ventilation. The objective of this study was to examine the incidence and risk factors associated with VAP, particularly in every 7-day versus every 14-day ventilator circuit changes, in a neonatal intensive care unit (NICU). Seventy-one neonates hospitalized in the NICU were enrolled. First, the neonates were divided into groups with and without VAP. On univariate logistic regression analyses, prolonged mechanical ventilation, frequent re-intubation, low gestational age, and low birth weight (BW) were significant risk factors for VAP development. After adjustments for other variables, only BW <626 g was a significant independent predictor for VAP in NICU infants. Second, to examine the effect of the frequency of changing ventilator circuits on the incidence of VAP, circuit changes were compared between the every 7-day group and the every 14-day group. The incidence of VAP per 1000 ventilator days was 9.66 for the every 7-day group and 8.08 for the every 14-day group, and there was no significant difference between the 2 groups. BW <626 g was a significant independent predictor of VAP, and decreasing the frequency of ventilator circuit changes from every 7 days to 14 days had no adverse effect on the VAP rate in the NICU.

Regional and temporal genotype profiling of Clostridioides difficile in a multi-institutional study in Japan.

Clostridioides difficile, a cause of healthcare-associated infections, poses a significant global health threat. This multi-institutional retrospective study focuses on epidemic dynamics, emphasizing minor and toxin-negative clinical isolates through high-resolution genotyping. The genotype of the C. difficile clinical isolates during 2005 to 2022 was gathered from 14 hospitals across Japan (N = 982). The total number of unique genotypes was 294. Some genotypes were identified in every hospital (cross-regional genotypes), while others were unique to a specific hospital or those in close geographic proximity (region-specific genotypes). Notably, a hospital located in a sparsely populated prefecture exhibited the highest prevalence of region-specific genotypes. The isolation rate of cross-regional genotypes positively correlated with the human mobility flow. A 6-month interval analysis at a university hospital from 2019 to 2021 revealed a temporal transition of the genotype dominance. The frequent isolation of identical genotypes over a brief timeframe did not always align with the current criteria for defining nosocomial outbreaks. This study highlights the presence of diverse indigenous C. difficile strains in regional environments. The cross-regional strains may have a higher competency to spread in the human community. The longitudinal analysis underscores the need for further investigation into potential nosocomial spread.

A national survey on myocarditis associated with influenza H1N1pdm2009 in the pandemic and postpandemic season in Japan.

An influenza pandemic occurred in 2009. We performed a retrospective national questionnaire survey about H1N1pdm2009 myocarditis to compare influenza A H1N1pdm2009 myocarditis in the pandemic (2009/2010) and postpandemic seasons (2010/2011) by collecting data from 360 hospitals. The diagnosis of myocarditis was performed using the guidelines for Diagnosis and Treatment of Myocarditis published by the Japanese Circulation Society (JCS 2009). Twenty-nine patients with influenza A H1N1pdm2009 myocarditis were reported, with 25 from the 2009/2010 season and only 4 patients from the 2010/2011 season. Morbidity and mortality was 28 % (8/29) among all the myocarditis patients. Six patients with myocarditis were complicated by pneumonia. Myocarditis was proved by endomyocardial biopsy or autopsy in 9 patients, although histological findings showed mild myocarditis even in clinically defined fulminant myocarditis cases. Seventeen patients were diagnosed with fulminant H1N1pdm2009 myocarditis with fatal arrhythmias or varying degrees of cardiogenic shock. Fifteen fulminant myocarditis patients were seen in the 2009/2010 season and only 2 in the 2010/2011 season. Ventilators were used in 16 patients. Mechanical circulatory support with intraaortic balloon pumping or percutaneous cardiopulmonary support (IABP/PCPS) was emergently inserted in 13 patients. Of these, 9 patients were rescued with mechanical circulatory support, and 4 patients died. Four fulminant myocarditis patients treated without IABP/PCPS died. We described the clinical features of patients with myocarditis associated with influenza H1N1pdm2009 in the pandemic and postpandemic seasons and demonstrated the high prevalence of fulminant myocarditis (17/29, 59 %). The number of patients with myocarditis associated with influenza A virus seemed to increase in the pandemic season.

[Effectiveness of intervention by the infection control team for cancer patients with a positive blood culture].

Cancer patients at a high risk of acquiring infectious diseases should be maintained in a facility where good infection control practices are followed. At our hospital, the infection control team(ICT)provides expertise, education, and support to the staff, helping them maintain proper standards, thereby minimizing the risks of infection. The ICT(established in 2004)has implemented infection control programs by employing an appropriate number of staff members after the revision of medical treatment fees in 2011. Our intervention program includes 2 general policies, namely, ordering and collection of blood cultures and intervention for the medical care of patients with positive blood cultures. In this study, we evaluated the effectiveness of our intervention for cancer patients with a positive blood culture. During the surveillance period(April 2011 to July 2012), 42 positive cases were determined to be infectious. ICT intervention was required in 37 cases. Our suggestions were accepted in 92%(34/37)of the cases, and improved outcome was estimated in 65%(22/34)of the cases. The results of our study contribute to the scientific bases on which routine clinical practices could be promoted in the future.

Effect of the introduction of a management bundle for blood culture collection.

BACKGROUND: Inappropriate blood collection subjected to blood culture (BC) causes BC contamination and may complicate the diagnose is of infectious diseases. Therefore, we developed a bundle based on the guideline recommendations for appropriate blood collection and examined the effects of bundle introduction. METHODS: We performed a retrospective analysis of BC samples to determine the contamination rates before and after introducing the BC bundle. We also analyzed the correlation between the compliance rate of the bundle and contamination rate, and between each bundle element and contamination. RESULTS: After the introduction of the bundle, the contamination rate was significantly reduced from 5.4% ± 0.9% to 1.7± 0.7% (P < .01). The compliance rate of the bundle was significantly associated with a lower contamination rate (P < .01). Multivariable logistic regression showed that collection from superficial veins of the cubital fossa (odds ratio [OR], 0.25; 95% confidence interval [CI], 0.13-0.51, P < .01) and disinfection of the skin at the blood collection site with 1% chlorhexidine alcohol swab (OR, 0.41; 95% CI, 0.25-0.68, P < .01) were significantly associated with lower contamination. CONCLUSIONS: This study suggests that the introduction of the BC bundle significantly reduced the contamination rate, and bundle compliance was associated with a lower contamination rate.

Adverse events after administration of the first and second doses of messenger RNA-based COVID-19 vaccines in Japanese subjects aged 12-18 years.

OBJECTIVE: Using a prospective observational design, we assessed adverse events (AEs) after COVID-19 vaccination in Japanese patients. METHODS: Two doses of the mRNA-1273 (SPIKEVAX®) or BNT162b2 (COMIRNATY®) vaccine were administered to participants aged 12 to 18 years, and AEs after each dose were recorded for 14 days. Data on the duration and nature (local vs. systemic) of AEs were collected using a questionnaire. Sex-based differences in AE frequency were also analyzed. RESULTS: After the first and second doses, 152 and 135 vaccinees were enrolled, respectively. After the first dose, fever (>37.1°C) occurred in 38.9% of males and 50.0% of females, whereas local pain occurred in 89.8% and 97.7% of males and females, respectively (only SPIKEVAX® was used as the first dose). After the second dose, fever (>37.1°C) occurred in 77.8% and 82.6% of males vaccinated with COMIRNATY® and SPIKEVAX®, respectively, and 82.6% of females (all received SPIKEVAX®). The local pain rates in these groups were 80.6%, 76.3%, and 100%, respectively. After the second dose, local pain, fever (>38.1°C) and headache were significantly more common in female participants, and the median symptom duration was 3 days. CONCLUSIONS: AEs were more frequent after the second dose and in females.

Young Healthy Patient With Severe COVID-19 and Fulminant Community-Acquired Pseudomonas aeruginosa Pneumonia: A Case Report.

Community-acquired pneumonia (CAP) caused by Pseudomonas aeruginosa in healthy adults can rapidly lead to severe outcomes. We treated a case of P. aeruginosa-induced CAP and concurrent severe coronavirus disease (COVID-19) in a healthy 39-year-old man without other serious risk factors for severe illness except smoking. Immediately after admission, the patient developed sepsis and received intensive broad-spectrum antibacterial therapy with meropenem and vancomycin, veno-arterial extracorporeal membrane oxygenation (VAECMO), and catecholamine supplementation. Despite receiving multidisciplinary treatment, the patient died within 24 hours. P. aeruginosa with normal antimicrobial susceptibility was identified in blood and sputum cultures of samples taken at admission. Gram staining of the bacteria detected in blood cultures was suspicious for non-glucose-fermenting Gram-negative rods, including P. aeruginosa, and the antimicrobial regimen that was initiated following admission was considered effective. The patient was a plumber and a smoker, which are risk factors for P. aeruginosa-induced CAP, and the clinical course matched those in previous reports of P. aeruginosa-induced CAP, including necrotizing pneumonia with cavities and rapid progression of sepsis. Although COVID-19 can be the sole cause of septic shock, the combination of P. aeruginosa bacteremia and COVID-19 was possibly the cause of septic shock in this case. Even during an infectious disease pandemic, reviewing the patient's occupational history and comorbidities and performing blood and sputum culture tests, including Gram staining, are important for the provision of appropriate treatment.

Probability of target attainment of oral antimicrobials for Escherichia coli and Klebsiella pneumoniae based on Monte Carlo simulations.

Although early transition from intravenous to oral antimicrobials can reduce hospitalization duration, susceptibility breakpoints have not been established for many oral antimicrobials against Escherichia coli and Klebsiella pneumoniae bacteremia. Thus, we used population pharmacokinetic models, pharmacokinetic/pharmacodynamic indices, and Monte Carlo simulations to evaluate the probability of target attainment (PTA) for common oral antimicrobial dosages against E. coli and K. pneumoniae. The oral antimicrobial agents evaluated included cephalexin, cefaclor, cefditoren, amoxicillin/clavulanic acid, faropenem, and levofloxacin. For E. coli, the percentage of isolates with minimum inhibitory concentrations for which a PTA >90% was achieved was 53% and less than 20% for levofloxacin and the ß-lactams, respectively. For K. pneumoniae, the percentages of isolates for which a PTA >90% was achieved were comparatively higher (cephalexin, 73%; amoxicillin/clavulanic acid, 83%; levofloxacin, 96%). Our results suggest clinicians should check if pharmacokinetic/pharmacodynamic indices are achieved in individual patients before transitioning to oral antimicrobial therapy.

Association between history of HBV vaccine response and anti-SARS-CoV-2 spike antibody response to the BioNTech/Pfizer's BNT162b2 mRNA SARS-CoV-2 vaccine among healthcare workers in Japan: A prospective observational study.

INTRODUCTION: Inadequate vaccine response is a common concern among healthcare workers at the frontlines of the COVID-19 pandemic. We aimed to investigate if healthcare workers with history of weak immune response to HBV vaccination are more likely to have weak responses against the BioNTech/Pfizer's BNT162b2 mRNA SARS-CoV-2 vaccine. METHODS: We prospectively tested 954 healthcare workers for the Anti-SARS-CoV-2 spike (S) protein antibody titers prior to the first and second BNT162b2 vaccination doses and after four weeks after the second dose using Roche's Elecsys® assay. We calculated the percentage of patients who seroconverted after the first and second doses. We estimated the relative risk of non-seroconversion after the first BNT162b2 vaccine (defined as anti-SARS-CoV-2-S titer <15 U/mL) among HBV vaccine non-responders (HBs-Ab titer <10 mIU/mL) and weak responders (≥10 and <100 mIU/mL) compared to normal responders (≥100 mIU/mL). RESULTS: Among 954 healthcare workers recruited between March 9 and March 24, 2021 at Osaka Medical and Pharmaceutical University, weak and normal HBV vaccine responders had comparable S-protein titers after the first BNT162b2 dose (51.4 [95% confidence interval 25.2-137.0] versus 59.7 [29.8-138.0] U/mL, respectively). HBV vaccine non-responders were more likely than normal responders to not seroconvert after a single dose (age and sex-adjusted relative risk 1.85 95% confidence interval [1.10-3.13]) although nearly all participants seroconverted after the second dose. After limiting the analysis to 382 patients with baseline comorbidity data, the comorbidity-adjusted relative risk of non-seroconversion among HBV vaccine non-responders to normal responders was 1.32 (95% confidence interval [0.59-2.98]). DISCUSSION: Long term follow-up studies are needed to understand if protective immunity against SARS-CoV-2 wanes faster among those with history of HBV vaccine non-response and when booster doses are warranted for these healthcare workers.

A Prospective Study Regarding the Efficacy and Safety of the BNT162b2 Vaccine in Patients With Solid Malignancies Undergoing Systemic Chemotherapy.

BACKGROUND/AIM: To prospectively evaluate the efficacy and safety of the BNT162b2 vaccine in solid cancer patients undergoing systemic chemotherapy (n=63). PATIENTS AND METHODS: COVID-19 anti-spike protein antibody levels were measured before the first BNT162b2 vaccination, just before the second BNT162b2 vaccination, one month after the second BNT162b2 vaccination, and 3 months after the second BNT162b2 vaccination. Anti-spike protein antibody seropositivity was set at ≥0.8 U/ml. RESULTS: Colorectal cancer was the most commonly observed primary disease (36.5%). ECOG-PS 0 was observed in the majority (52.4%) of patients. The overall response rate and the median (range) anti-spike protein antibody levels in the whole cohort at 3 months after the second BNT162b2 vaccination were 98.4% (62/63) and 206 (0.4-3,813) U/ml. None of the patients required postponement or discontinuation of systemic chemotherapy because of an adverse reaction. CONCLUSION: The BNT162b vaccine in solid cancer patients undergoing systemic chemotherapy is effective and safe.

Inhalation of hydrogen gas attenuates left ventricular remodeling induced by intermittent hypoxia in mice.

Sleep apnea syndrome increases the risk of cardiovascular morbidity and mortality. We previously reported that intermittent hypoxia increases superoxide production in a manner dependent on nicotinamide adenine dinucleotide phosphate and accelerates adverse left ventricular (LV) remodeling. Recent studies have suggested that hydrogen (H(2)) may have an antioxidant effect by reducing hydroxyl radicals. In this study, we investigated the effects of H(2) gas inhalation on lipid metabolism and LV remodeling induced by intermittent hypoxia in mice. Male C57BL/6J mice (n = 62) were exposed to intermittent hypoxia (repetitive cycle of 1-min periods of 5 and 21% oxygen for 8 h during daytime) for 7 days. H(2) gas (1.3 vol/100 vol) was given either at the time of reoxygenation, during hypoxic conditions, or throughout the experimental period. Mice kept under normoxic conditions served as controls (n = 13). Intermittent hypoxia significantly increased plasma levels of low- and very low-density cholesterol and the amount of 4-hydroxy-2-nonenal-modified protein adducts in the LV myocardium. It also upregulated mRNA expression of tissue necrosis factor-α, interleukin-6, and brain natriuretic peptide, increased production of superoxide, and induced cardiomyocyte hypertrophy, nuclear deformity, mitochondrial degeneration, and interstitial fibrosis. H(2) gas inhalation significantly suppressed these changes induced by intermittent hypoxia. In particular, H(2) gas inhaled at the timing of reoxygenation or throughout the experiment was effective in preventing dyslipidemia and suppressing superoxide production in the LV myocardium. These results suggest that inhalation of H(2) gas was effective for reducing oxidative stress and preventing LV remodeling induced by intermittent hypoxia relevant to sleep apnea.

A national survey on myocarditis associated with the 2009 influenza A (H1N1) pandemic in Japan.

BACKGROUND: An influenza pandemic occurred in 2009 and myocarditis associated with the 2009 influenza A (H1N1) pandemic was reported among hospitalized patients from August 2009. METHODS AND RESULTS: The Japanese Circulation Society organized the Clinical Research Committee on Myocarditis Associated with Influenza Pandemic A (H1N1) 2009 and called for a case report on myocarditis for a national survey. The diagnosis of myocarditis was performed using the Guidelines for the Diagnosis and Treatment of Myocarditis (JCS 2009). Fifteen patients were reported to the committee. Fulminant myocarditis developed in 10 patients. Mechanical circulatory support (intra-aortic balloon pumping (IABP) and/or percutaneous cardiopulmonary support (PCPS)) was used on all 10 patients, 8 of whom were rescued. Abnormalities on echocardiography and elevated cardiac enzymes were seen in most of the patients. Myocarditis was found by endomyocardial biopsy in 6 patients. Three patients had complications with pneumonia. CONCLUSIONS: In reality, myocarditis associated with pandemic influenza A (H1N1) seemed to be more common in hospitalized patients, compared with previous seasonal influenza virus outbreaks. To avoid misdiagnosis of acute myocarditis associated with influenza pandemic A (H1N1) 2009, it is essential to determine the characteristic symptoms, signs, and laboratory findings of acute myocarditis during influenza pandemics. Mechanical circulatory support (IABP and/or PCPS) was required to rescue patients with fulminant myocarditis.

Effects of acarbose on the acceleration of postprandial hyperglycemia-induced pathological changes induced by intermittent hypoxia in lean mice.

Postprandial hyperglycemia (PPH) and intermittent hypoxia related to the sleep apnea syndrome are important predictors of cardiovascular disease. We investigated the effects of intermittent hypoxia on pathological changes in the left ventricular (LV) myocardium caused by PPH in lean mice and evaluated the influence of acarbose, an α-glucosidase inhibitor. Male C57BL/6J mice aged 8 weeks were exposed to intermittent hypoxia (8 h/day during the daytime) or kept under normoxia. PPH was induced by restriction of feeding to 1-h periods twice a day, with the restricted diet (RD) mice receiving either standard chow or chow containing 0.02% acarbose. Another group of mice were fed standard chow ad libitum (AL). Plasma glucose levels after food intake were significantly elevated in RD but not in AL mice, and glucose levels were suppressed by acarbose. Intermittent hypoxia exacerbated cardiomyocyte hypertrophy and interstitial fibrosis in the LV myocardium of RD mice. Superoxide production and expression of 4-hydroxy-2-nonenal in the LV myocardium with intermittent hypoxia were increased in RD mice, but not AL mice. In addition, expression of tumor necrosis factor α (TNF-α) mRNA was increased in hypoxic RD mice. Treatment with acarbose inhibited oxidative stress and TNF-α mRNA expression and preserved the histological architecture of the LV myocardium.