Identification of groundwater microbes that decrease the concentration of the conservative tracer uranine.

Fluorescent dyes are commonly used as conservative groundwater tracers to track the migration of water. Over- or underestimation of important parameters such as the water flow rate can occur if the concentration of a dye is changed by unexpected reactions. Because such errors may seriously affect the results of experiments, the reactions and processes that change fluorescent dye concentrations need to be understood. In this study, we focused on the widely used fluorescent dye uranine (UR) and aimed to identify microbes contributing to decreases in UR concentrations in groundwater. First, we identified the conditions (water temperature, pH, and salinity) under which significant decreases in UR concentrations occurred to show that the decrease in UR concentrations were caused by the effects of microbes in the groundwater. Next, we obtained information about the metabolism of organic matter by potential contributing microbes. These results were used to narrow down possible microbes that could decrease the UR concentration. Analysis of the microbial community in groundwater using 16S rRNA gene sequencing was then used to further identify contributing microbes. Finally, a verification experiment was conducted using a strain of one of the identified microbes (Parapontixanthobacter aurantiacus). Our results showed that conservation of the concentration of fluorescent dye solutions prepared with on-site groundwater was affected by several microbes with different metabolic characteristics, including P. aurantiacus. When fluorescent dye solutions prepared with on-site groundwater are used in field investigations or tracer tests, the pros and cons of using fluorescent dyes should be carefully evaluated because of the potential effects of microbes in the groundwater.

Effects of TiO2 and ZnO nanoparticles on the growth of phytoplankton assemblages in seawater.

Compounds in sunscreen such as ultraviolet (UV) filters protect human skin from damage caused by UV radiation exposure. However, sunscreen components reach marine ecosystems after their release from human skin during activities such as swimming and washing, and are potentially toxic to marine organisms. TiO2 and ZnO nanoparticles (NPs) are commonly used as inorganic UV filters. In this study, we explored the effects of TiO2 and ZnO NPs on natural phytoplankton assemblages in coastal seawater. Growth rates of natural phytoplankton assemblages were significantly decreased by 10 mg L-1 TiO2 and 1 and 10 mg L-1 ZnO NP treatments. NP addition also modified the size structure of phytoplankton assemblages, and small phytoplankton (mainly cyanobacteria) are vulnerable to NPs. Because herbivore food preferences depend strongly on algal cell size, NP contamination could also affect higher trophic levels. Notably, small phytoplankton are an important component in microbial loop, and this energy transfer pathway may be more vulnerable to NP contamination.

Predictors of oxygenation impairment in medical treatment for type B acute aortic dissection.

Lung oxygenation impairment often occurs in patients with type B acute aortic dissection (AAD), necessitating mechanical ventilation. Patients receiving mechanical ventilation are at risk of complications, so a low-oxygen condition requiring mechanical ventilation should be avoided. We explored the predictors of oxygenation impairment. We enrolled 46 patients with type B AAD who had been medically treated and underwent computed tomography. Blood was sampled to measure markers of inflammation, such as the C-reactive protein (CRP) levels and white blood cell count. The arterial partial pressure of oxygen/fraction of inspired oxygen ratio (PaO2/FiO2) was calculated to quantify the severity of respiratory failure. Spearman's rank correlation analysis revealed that the minimum PaO2/FiO2 ratio was significantly correlated with gender, age, and current smoker, and the peak CRP, body temperature, and D-dimer values. A multivariate regression analysis revealed that younger age, male sex, and the peak CRP level were significant predictors of the minimum PaO2/FiO2 ratio (P = 0.01, 0.035 and 0.005, respectively). A covariance structure analysis showed that a younger age and the peak CRP level were significant predictors of oxygenation impairment in type B AAD. Oxygenation impairment in type B AAD is correlated with younger age and a higher peak CRP level. This will enable the identification of patients whose respiratory condition is susceptible to worsening and help prevent mechanical ventilation, leading to the provision of appropriate therapy.

The Usefulness and Limitations of Point-of-care Cardiac Troponin Measurement in the Emergency Department.

Objective This study was carried out to examine the usefulness of point-of-care (POC) cardiac troponin in diagnosing acute coronary syndrome (ACS) and to understand the limitations of a POC cardiac troponin I/T-based diagnoses. Methods Patients whose cardiac troponin levels were measured in the emergency department using a POC system (AQT System; Radiometer, Tokyo, Japan) between January and December 2016 were retrospectively examined (N=1,449). Patients who were < 20 years of age or who were admitted with cardiopulmonary arrest were excluded. The sensitivity and specificity of the POC cardiac troponin levels for the diagnosis of ACS were determined. Result One hundred and twenty of 1,449 total patients had ACS (acute myocardial infarction, n=88; unstable angina n=32). On comparing the receiver operating characteristic (ROC) curves, the area under the curve (AUC) values for POC cardiac troponin I and cardiac troponin T were 0.833 and 0.786, respectively. The sensitivity and specificity of POC cardiac troponin I when using the 99th percentile (0.023 ng/mL) as the diagnostic cut-off value were 69.0% and 88.1%, respectively. The sensitivity of POC cardiac troponin I (99th percentile) was higher in the patients sampled > 3 hours after symptom onset (83.3%) than in those sampled ≤ 3 hours after symptom onset (58.8%, p < 0.01). Conclusion When sampled > 3 hours after the onset of symptoms, the POC cardiac troponin I level is considered to be suitable for use in diagnosing ACS. However, when sampled ≤ 3 hours after the onset of symptoms, careful interpretation of POC cardiac troponins is therefore required to rule out ACS.

Diabetes is a predictor of coronary artery stenosis in patients hospitalized with heart failure.

In patients with heart failure, coronary artery disease is the most common underlying heart disease, and is associated with increased mortality. However, estimating the presence or absence of coronary artery disease in patients with heart failure is sometimes difficult without coronary imaging. We reviewed 155 consecutive patients hospitalized with heart failure who underwent coronary angiography. The patients were divided into two groups: patients with (N = 59) and without (N = 96) coronary artery stenosis. The clinical characteristics and blood sampling data were compared between the two groups. The patients with coronary artery stenosis were older than those without. The prevalence of diabetes mellitus (DM), dyslipidemia and a history of revascularization was higher in the patients with coronary artery stenosis. Patients with coronary artery stenosis tended to have wall motion asynergy more frequently than those without. On the other hand, the prevalence of atrial fibrillation (AF) was lower in patients with coronary artery stenosis. The serum hemoglobin level and estimated glomerular filtration rate were lower in patients with coronary artery stenosis than in those without. In the multivariate analysis, DM (odds ratio 3.517, 95 % CI 1.601-7.727) was found to be the only the predictor of the presence of coronary artery stenosis in patients with heart failure. In conclusion, coronary imaging is strongly recommended for heart failure patients with DM to confirm the presence of coronary artery stenosis.

The Optimal Cut-off Value of Plasma BNP to Differentiate Heart Failure in the Emergency Department in Japanese Patients with Dyspnea.

OBJECTIVE: In the emergency department, it is sometimes difficult to differentiate heart failure (HF) from other diseases (e.g., respiratory diseases) in patients who develop dyspnea. The plasma B-type natriuretic peptide (BNP) levels increase in patients with HF, and various levels are associated with specific New York Heart Association classes. Although the diagnosis of HF should not be made based only on the plasma BNP levels, the identification of a cut-off value for BNP to diagnose HF would be helpful. METHODS: Patients admitted to the emergency department of our hospital with dyspnea between January 2010 and December 2011 were retrospectively reviewed. The patients whose estimated glomerular filtration rate was less than 30 mL/min/1.73 m(2) were excluded. Patients were divided into two groups: those with HF (n=131) and those without HF (n=138). The cut-off value for BNP was determined by the receiver-operating characteristic curve. RESULTS: The area under the curve of this curve was 0.934. The optimal cut-off point for detection of HF was 234 pg/mL. The sensitivity and specificity were 87.0% and 85.5%, respectively. The fifth and 95th percentiles of the HF group were 132.2 and 2,420.8 pg/mL, respectively. Those of the non-HF group were 9.7 and 430.2 pg/mL, respectively. CONCLUSION: Our study suggests that a plasma BNP level cut-off value of 234 pg/mL can be used to detect HF in the emergency department.

Midterm outcomes of bare-metal stenting after primary stenting for ST-segment elevated myocardial infarctions in the drug-eluting stent era: a propensity score-matched comparison with sirolimus-eluting stent.

We performed a propensity score-matching comparison of the midterm clinical and angiographic outcomes after primary stenting between using bare-metal stents (BMSs) and sirolimus-eluting stent (SES; Cypher Bx Velocity) for ST-segment elevated myocardial infarction (STEMI), because, in the drug-eluting stent era, the indication of the BMSs when a large balloon diameter is required remained to be controversial. This was a single-center, nonrandomized, retrospective study investigated in October 2013 by enrolling STEMI patients treated with primary stenting using either SES (n = 468) or BMS (n = 171) between September 2004 and December 2011. In 204 patients, the baseline-adjusted values produced similar mean maximum balloon sizes (BMS 3.67 ± 0.47 mm; SES 3.70 ± 0.56 mm; p = 0.477), and the incidence rates of binary in-stent restenosis (% diameter stenosis >50 % on secondary angiography) after SES placement (7.8 %) was significantly lower than that after BMS placement (23.5 %; p = 0.002). In baseline-adjusted 300 patients, the incidence of the clinical endpoints comprising cardiac death, nonfatal recurrent MI, and definite stent thrombosis after SES placement (11.3 %; 1241 ± 786 days; p = 0.557) was not significantly different from after BMS placement (8.7 %; mean follow-up period, 549 ± 486 days; p = 0.557). SES was not significantly related to the clinical endpoint [hazard ratio 2.31; 95 % confidence interval (CI) 0.88-6.08; p = 0.089). BMS did not offset the SES's angiographic efficacy for primary stenting for STEMI patients, despite placed using a large-sized balloon.

Post-discharge clinical and angiographic outcomes of patients presenting within 48h of STEMI treated with paclitaxel- or sirolimus-eluting stents.

BACKGROUND AND PURPOSE: The purpose of the present study was to examine the mid-term clinical and angiographic outcomes of patients with ST-segment elevation myocardial infarction (STEMI) who presented within 48 h and received paclitaxel-eluting stents (PES) or sirolimus-eluting stents (SES). METHODS AND RESULTS: This study was a retrospective, non-randomized, single-center study. The post-discharge clinical outcomes of 357 consecutive patients who presented within 48 h of their first STEMI and received PES (n=163) or SES (n=194) between February 2007 and February 2009 were analyzed in May 2011. The incidence of post-discharge events (i.e. cardiac death and non-fatal recurrent MI) after PES placement (0.6%) did not significantly differ from that after SES placement (1.5%). Treatment with PES was not related to the risk of adverse events post-discharge (mean follow-up period for PES placement, 1170±243 days; hazard ratio, 0.346; 95% CI, 0.036-3.371; p=0.361). No definite stent thromboses developed after treatment with PES or SES. The incidence of binary in-stent restenosis (stenosis of more than 50% of the diameter at secondary angiography performed 10-18 months after the initial procedure) after PES placement (17.1%) was significantly higher than that after SES placement (4.8%; p<0.001). PES placement was an independent predictor of binary in-stent restenosis (odds ratio, 3.892; 95% CI, 1.470-10.30; p=0.006). CONCLUSIONS: Retrospective examination of the post-discharge clinical course after placement of PES and SES showed favorable midterm clinical outcomes among Japanese STEMI patients treated within 48h of onset. However, SES treatment resulted in superior angiographic outcomes compared to PES.

Retrospective comparison of clinical and angiographic outcomes after primary stenting using sirolimus-eluting and bare-metal stents in nonrandomized consecutive 568 patients with first ST-segment elevated myocardial infarctions.

BACKGROUND AND PURPOSE: The long-term safety and efficacy of primary stenting using drug-eluting stents (DES) in patients with ST-segment elevation myocardial infarction (STEMI) are not fully understood in Japan. Therefore, we retrospectively examined the midterm clinical and angiographic outcomes in STEMI patients after primary stenting using sirolimus-eluting stents (SES) in a clinical setting through a historical comparison with those of bare-metal stents (BMS). METHODS AND RESULTS: The study design was a retrospective, nonrandomized, and single-center study. The clinical outcomes for 568 consecutive patients who presented within 12 h of their first STEMI and who were treated with BMS (n = 198; 184 STEMIs from June 2003 to August 2004 and 14 STEMIs from September 2004 to May 2007) or SES (n = 370; from August 2004 to May 2007) at our medical center in Japan were retrospectively investigated in February 2010. The incidence of post-discharge events (comprising cardiac death and nonfatal recurrent MI) after SES placement (3.9%) was not significantly different from that after BMS placement (6.7%). SES was not related to the risk of post-discharge events (mean follow-up for SES, 1327 ± 415 days; BMS, 1818 ± 681 days) (hazard ratio of 0.369 at 95% CI, 0.119-1.147, p = 0.085). The incidence of definite stent thromboses after SES placement (0.54%) was not significantly higher than that after BMS placement (0%). The incidence of binary in-stent restenosis (% diameter stenosis of more than 50% at secondary angiography) after SES placement (8.3%) was significantly lower than that after BMS placement (25.7%; p < 0.001). CONCLUSIONS: From the present historical comparison of SES and BMS, we conclude that primary stenting using SES in a clinical setting has favorable clinical and angiographic outcomes in Japanese STEMI patients.