Health risk assessment and source apportionment of PM2.5-bound toxic elements in the industrial city of Siheung, Korea.

The emission sources and their health risks of fine particulate matter (PM2.5) in Siheung, Republic of Korea, were investigated as a middle-sized industrial city. To identify the PM2.5 sources with error estimation, a positive matrix factorization model was conducted using daily mean speciated data from November 16, 2019, to October 2, 2020 (95 samples, 22 chemical species). As a result, 10 sources were identified: secondary nitrate (24.3%), secondary sulfate (18.8%), traffic (18.8%), combustion for heating (12.6%), biomass burning (11.8%), coal combustion (3.6%), heavy oil industry (1.8%), smelting industry (4.0%), sea salts (2.7%), and soil (1.7%). Based on the source apportionment results, health risks by inhalation of PM2.5 were assessed for each source using the concentration of toxic elements portioned. The estimated cumulative carcinogenic health risks from the coal combustion, heavy oil industry, and traffic sources exceeded the benchmark, 1E-06. Similarly, carcinogenic health risks from exposure to As and Cr exceeded 1E-05 and 1E-06, respectively, needing a risk reduction plan. The non-carcinogenic risk was smaller than the hazard index of one, implying low potential for adverse health effects. The probable locations of sources with relatively higher carcinogenic risks were tracked. In this study, health risk assessment was performed on the elements for which mass concentration and toxicity information were available; however, future research needs to reflect the toxicity of organic compounds, elemental carbon, and PM2.5 itself.

Novel Method for S1 Transforaminal Epidural Steroid Injection.

BACKGROUND: S1 transforaminal epidural steroid injection (S1-TFESI) results in positive clinical outcomes for the treatment of pain associated with the S1 nerve root. S1-TFESI via the transforaminal approach is commonly performed under fluoroscopic guidance. Ultrasound guidance is an alternative to mitigate radiation exposure. However, performing spinal procedures under ultrasound guidance has some limitations in confirming the position of the needle tip and vascular uptake. New techniques are therefore needed to make ultrasound and fluoroscopy complementary. Our objective was to describe a novel technique for S1-TFESI and confirm its reproducibility. METHODS: Records of patients with S1 radiculopathy were reviewed retrospectively; those treated using the new S1-TFESI technique were selected. Initially, ultrasound was used to distinguish anatomy of the sacral foramen and guide initial placement of the needle entry point. Fluoroscopy was subsequently used to confirm needle tip position and vascular injection. The number of times the needle required reinsertion was recorded, and ultrasound and C-arm images were stored. RESULTS: Sixty-seven S1-TFESIs were performed in 56 patients. All injections exhibited epidural spread of contrast media, not only to the S1 nerve. The cephalad angle was 16.25 ± 6.75° (range, 5-27°), the oblique angle was 2.48 ± 2.62° (range, 0-7°), and the mean number of attempts was 1.24 ± 1.25. CONCLUSIONS: The new technique, involving the use of ultrasound to guide initial placement of the needle entry point, followed by confirmatory imaging and any needed adjustment with the use of fluoroscopy, can be a technique to complement the shortcomings of using ultrasound or fluoroscopy alone.

Characterization of Clostridium difficile Strains Isolated from Patients with C. difficile-associated Disease in Korea.

OBJECTIVES: Studies on Clostridium difficile are rare in Korea. We investigated the epidemiological characteristics of C. difficile isolates from patients with C. difficile-associated disease (CDAD) in Korea. METHODS: Multiplex polymerase chain reaction was performed to detect the presence of tcdA and tcdB toxin genes. Antimicrobial susceptibility test was carried out by the disk-dilution method. C. difficile strains were subtyped by automated repetitive-element palindromic PCR (rep-PCR). RESULTS: Among patients with CDAD, 73 (25.8%), 32 (11.3%), 32 (11.3%), and 26 (9.2%) suffered from pneumonia, cancer or neoplasm, diabetes, and colitis, respectively. Of all stool samples, 43 samples (15.2%) were positive for C. difficile strains. We observed two expression patterns of toxin genes: tcdA+/tcdB+ (86% isolates) and tcdA-/tcdB+ (14% isolates), with all isolates expressing tcdB. Furthermore, some isolates were resistant to clindamycin (65%), ampicillin (56%), and cefazolin (40%), but all were susceptible to vancomycin and metronidazole. The tested samples were classified into diverse clusters using automated rep-PCR. CONCLUSION: Our findings revealed the characteristics and antibiotic resistance of C. difficile isolates from patients in Korea. The epidemiological data may provide valuable insight into development of treatment strategies for C. difficile infections in Korea.

Efficacy and Tolerability of Combination Therapy Versus Monotherapy with Candesartan and/or Amlodipine for Dose Finding in Essential Hypertension: A Phase II Multicenter, Randomized, Double-blind Clinical Trial.

PURPOSE: Intensive blood pressure (BP) lowering is important for the treatment of hypertension; however, it has been a challenge to achieve target BP in many patients. The purpose of this study was to explore the optimal dosage of a fixed-dose combination of candesartan cilexetil (CAN) and amlodipine besylate (AML), by examining the tolerability and efficacy of CAN/AML combination therapy compared with those of monotherapy with either drug in patients with essential hypertension. METHODS: This Phase II multicenter, randomized, double-blind clinical trial enrolled patients aged 19 years or older with essential hypertension, defined as a mean sitting diastolic BP (msDBP) between 95 and 115 mm Hg, and a mean sitting systolic BP (msSBP) of <200 mm Hg after a 2-week placebo run-in period. A total of 635 patients were screened, of whom 439 were randomized to receive treatment; 425 patients were included in the full analysis set (combination therapy, 212; monotherapy, 213). Participants were randomly assigned to receive 1 of 8 treatments: CAN (8 or 16 mg), AML (5 or 10 mg), CAN/AML (8 mg/5 mg, 8 mg/10 mg, 16 mg/5 mg, or 16 mg/10 mg), once daily for 8 weeks. FINDINGS: After 8 weeks of treatment, changes in msDBP were significantly greater in the groups receiving CAN/AML combination therapies compared with monotherapies at matched doses, with the exception of CAN 8 mg/AML 10 mg versus AML 10 mg. The response to treatment and the achievement of target BP (both msSBP and msDBP) at week 8 were significantly greater overall in the groups that received combination therapy versus monotherapy. All medications were relatively well tolerated in each group. IMPLICATIONS: Eight-week administration of CAN/AML (8 mg/5 mg, 16 mg/5 mg, and 16 mg/10 mg) resulted in a significantly greater BP reduction than that with CAN or AML monotherapy, and was determined to be well tolerated. ClinicalTrials.gov identifier: NCT02944734.

Three-dimensional digital microfluidic manipulation of droplets in oil medium.

We here develop a three-dimensional DMF (3D DMF) platform with patterned electrodes submerged in an oil medium to provide fundamental solutions to the technical limitations of 2D DMF platforms and water-air systems. 3D droplet manipulation on patterned electrodes is demonstrated by programmably controlling electrical signals. We also demonstrate the formation of precipitates on the 3D DMF platform through the reaction of different chemical samples. A droplet containing precipitates, hanging on the top electrode, can be manipulated without adhesion of precipitates to the solid surface. This method could be a good alternative strategy to alleviate the existing problems of 2D DMF systems such as cross-contamination and solute adsorption. In addition, we ascertain the feasibility of temperature-controlled chemical reaction on the 3D DMF platform by introducing a simple heating process. To demonstrate applicability of the 3D DMF system to 3D biological process, we examine the 3D manipulation of droplets containing mouse fibroblasts in the 3D DMF platform. Finally, we show detachment of droplets wrapped by a flexible thin film by adopting the electro-elasto-capillarity (EEC). The employment of the EEC may offer a strong potential in the development of 3D DMF platforms for drug encapsulation and actuation of microelectromechanical devices.

Effects of prophylactic ramosetron and ondansetron on corrected QT interval during general anesthesia.

STUDY OBJECTIVE: To evaluate whether ramosetron increases the corrected QT (QTc) interval. DESIGN: Prospective, randomized, controlled study. SETTING: Operating room. PATIENTS: 135 patients undergoing elective laparoscopic cholecystectomy. INTERVENTION: Patients were allocated to three groups to receive ondansetron 4 mg (Group O4), ramosetron 0.3 mg (Group R), or ondansetron 8 mg (Group O8). The study drugs were administered intravenously approximately 15 minutes before the end of surgery. MEASUREMENT: The QT interval for 10 minutes after administration was recorded. The QTc interval was calculated according to the Fridericia (QTcF) formula. The primary outcome was the QTcF interval among the three groups during the 10 minutes after administration of the study drugs. MAIN RESULTS: The QTcF interval was not significantly prolonged after administration of ondansetron 4 mg and ramosetron. It was significantly increased from one minute after administration until 7 minutes after ondansetron 8 mg (Group O8). The QTcF interval was significantly longer in Group O8 at 1, 2, 3, 4, and 5 minutes. CONCLUSIONS: The prophylactic administration 0.3 mg of ramosetron does not increase the QTc interval. Ondansetron 8 mg increases the QTc interval more so than 4 mg of ondansetron.

Efficacy and tolerability of amlodipine camsylate/losartan 5/100-mg versus losartan/hydrochlorothiazide 100/12.5-mg fixed-dose combination in hypertensive patients nonresponsive to losartan 100-mg monotherapy.

PURPOSE: The aim of this study was to determine whether the efficacy and tolerability of amlodipine camsylate/losartan 5/100 mg/d (AML/LOS) are noninferior to those of losartan/hydrochlorothiazide 100/12.5 mg/d (LOS/HCTZ) fixed-dose combination in hypertensive patients unresponsive to losartan 100-mg/d monotherapy. METHODS: Male and female patients aged ≥ 18 years with hypertension despite 4-week, stable treatment with losartan 100-mg/d monotherapy were eligible for inclusion in this multicenter, randomized, double-blind study. Patients were randomly assigned to receive AML/LOS or LOS/HCTZ once daily for 8 weeks. The primary end point was the change from baseline to week 8 in sitting diastolic blood pressure (ΔsiDBP), and the secondary end points were the changes from baseline to 4 weeks in siDBP and sitting systolic BP (ΔsiSBP) and changes from baseline to 4 and 8 weeks in BP response rate. Tolerability was evaluated by physical examination, including vital sign measurement; laboratory analysis; and ECG. FINDINGS: Of 275 patients screened at 9 cardiovascular centers, 199 were enrolled (AML/LOS, n = 101; LOS/HCTZ, n = 98), and 183 completed the study. The demographic characteristics were similar between the 2 groups (mean age, 51.56 [9.97] years; men, 70.53%). At 8 weeks, the mean ΔsiDBP values were -11.54 (7.89) and -9.05 (6.57) mm Hg in the AML/LOS and LOS/HCTZ groups, respectively (both, P < 0.0001 vs baseline). The mean difference between the 2 groups was -2.57 mm Hg, a nonsignificant difference, meaning that AML/LOS was noninferior to LOS/HCTZ with regard to the primary end point. At 8 weeks, the mean uric acid level was changed significantly from baseline in the LOS/HCTZ group (+0.41 [0.80] mg/dL; P < 0.0001) but not in the AML/LOS group (-0.12 [0.82] mg/dL), representing a significant intergroup difference (P < 0.0001). Nineteen patients each in the AML/LOS (18.81%) and LOS/HCTZ (20.00%) groups experienced ≥ 1 adverse event, with 4 (3.96%) and 3 (3.16%) patients, respectively, experiencing 1 or more events considered by the investigators to have been treatment related. IMPLICATIONS: The efficacy and tolerability of AML/LOS 5/100 mg/d was found to have been noninferior to those of LOS/HCTZ 100/12.5 mg/d in these hypertensive patients nonresponsive to losartan 100-mg/d monotherapy.

Brachial-ankle pulse wave velocity for the prediction of the presence and severity of coronary artery disease.

The predictability of brachial-ankle pulse wave velocity (baPWV) for the presence and severity of coronary artery disease (CAD) was investigated by measuring baPWV in 501 subjects scheduled for coronary angiography. Severity of CAD was measured using modified Gensini stenosis score (GSS) and classified as a vessel disease score (VDS) of 0-3. The presence of CAD was defined as diameter stenosis>50%. Subjects were grouped in tertile by level of baPWV (<14, 14-17, >17 m/s). Subjects with CAD showed higher mean age, prevalence of men and diabetes, and systolic blood pressure. The prevalence of hypertension, use of antihypertensive medications and use of statin was not different. Subjects with CAD had higher baPWV than subjects without CAD (16.70 ± 3.46 versus 15.21 ± 3.19 m/s, p<0.001). Multiple linear regression analysis showed significant correlation of baPWV and modified GSS (p=0.0337). ANCOVA adjusted with age, gender, body mass index, presence of hypertension or diabetes, status of smoking, use of antihypertensive medications and risk of hypercholesterolemia showed a statistically significant association of baPWV with VDS (p<0.0001). Highest tertile of baPWV had a statistically significant effect on the severity of CAD from an ANCOVA model. The predictive power of highest tertile of baPWV for the presence of CAD was 3.600 [95% confidence interval (CI) 1.884-6.881, p<0.0001]. It is concluded that increased baPWV is a reliable predictor of the presence and severity of CAD, suggesting that baPWV>17 m/s may be a threshold value for the presence and severity of CAD.

A small-molecule inducer of PDX1 expression identified by high-throughput screening.

Pancreatic and duodenal homeobox 1 (PDX1), a member of the homeodomain-containing transcription factor family, is a key transcription factor important for both pancreas development and mature ß cell function. The ectopic overexpression of Pdx1, Neurog3, and MafA in mice reprograms acinar cells to insulin-producing cells. We developed a quantitative PCR-based gene expression assay to screen more than 60,000 compounds for expression of each of these genes in the human PANC-1 ductal carcinoma cell line. We identified BRD7552, which upregulated PDX1 expression in both primary human islets and ductal cells, and induced epigenetic changes in the PDX1 promoter consistent with transcriptional activation. Prolonged compound treatment induced both insulin mRNA and protein and also enhanced insulin expression induced by the three-gene combination. These results provide a proof of principle for identifying small molecules that induce expression of transcription factors to control cellular reprogramming.

Increased pulse wave velocity reflecting arterial stiffness in patients with colorectal adenomas.

The obese patients with diabetes or cardiovascular risk factors are associated with increased risk of colorectal cancer as well as adenomas under the shared pathogenesis related to atherosclerosis. Here we determined the association between increased arterial stiffness and colorectal adenomas incorporating parameters including age, gender, waist circumference, body mass index, lipid profiles, fasting glucose, and blood pressure. Subjects who simultaneously underwent colonoscopies and pulse wave velocity (PWV) determinations between July 2005 and September 2006 were analyzed, based on which the subjects were classified into two groups as patients group with colorectal adenomas (n = 49) and control group (n = 200) with normal, non-polypoid benign lesions or hyperplastic polyps. Uni- and multi-variate analyses were performed to calculate the odd ratio for colon adenomas. Based on uni-variate analysis, age, waist circumference, body mass index, heart-femoral PWV (hfPWV), and brachial-ankle PWV were significantly associated with adenomas (p<0.05) and multiple logistic regression analysis showed that the heart-femoral PWV, waist circumference, and the levels of LDL-C were significant risk factor for colorectal adenoma. However, arterial stiffness did not affect the progression of colon adenoma. The finding that hfPWV, reflecting aortic stiffness, was increased in patients with colorectal adenomas lead to conclusion that patients who have prominently increased arterial stiffness can be recommended to undergo colonoscopic examinations and at the same time we also recommend counseling about the risk for atherosclerosis in those who have colorectal adenomas.

Relationship between serum uric Acid levels, metabolic syndrome, and arterial stiffness in korean.

BACKGROUND AND OBJECTIVES: Associations have been reported between the serum uric acid (SUA) level, metabolic syndrome (MS), and atherosclerosis. We have determined the relationship between the SUA level, MS, and arterial stiffness in Korean. SUBJECTS AND METHODS: Cross-sectional data from 1,276 adults who underwent routine laboratory tests and pulse wave velocity (PWV) measurements during a health check-up were analyzed in a gender-specific manner. None of the participants had atherosclerotic cardiovascular disease, diabetes, renal disease, or systemic disease, or were under treatment which would affect SUA levels, or taking medications for hypertension or dyslipidemia. RESULTS: After adjustment for age, smoking status, total cholesterol (TC), and creatinine, the odds ratios (ORs, 95% confidence interval) of gender-specific quartiles of SUA for MS were 1.0, 1.28 (0.66-2.47), 1.46 (0.76-2.82), and 2.21 (1.15-4.26) in females, and 1.0, 1.33 (0.82-2.17), 1.60 (0.96-2.66), and 2.03 (1.21-3.40) in males. However, after adjustment for waist circumference, there were no significant differences in the ORs among the SUA quartile groups in females and males (both, p=NS). The Pearson's correlation coefficients for the relationship between SUA levels and heart-femoral (hf) PWVs or brachial-ankle (ba) PWVs were not significant in females and males (r=0.054 and r=0.015, respectively, in females; r=-0.036 and r=-0.015, respectively, in males; all, p=NS). CONCLUSION: An elevated SUA level is associated with abdominal obesity among the MS components, but the SUA level is not associated with PWV in females or males.

Acute effects of cigarette smoking on arterial stiffness and blood pressure in male smokers with hypertension.

BACKGROUND: Although the acute increase of arterial stiffness and blood pressure (BP) after cigarette smoking in healthy smokers is considered a possible mechanism of increased cardiovascular risk, the acute effect of smoking on arterial stiffness in hypertensive smokers is unknown. We investigated the acute effects of cigarette smoking on arterial stiffness and BP in hypertensive male smokers. METHODS: Heart rate (HR), brachial and ankle BP, and pulse-wave velocity (PWV) were measured in 22 hypertensive male smokers (HTs) and in 30 normotensive male smokers (NTs) before and 5, 10, and 15 min after smoking one cigarette (nicotine content, 0.9 mg). RESULTS: Smoking induced acute increases of HR, brachial BP, and heart-femoral PWV (hfPWV) in NTs and HTs (P < .05). Ankle systolic BP and femoral-ankle PWV were acutely increased in HTs (P < .05), but not in NTs. In HTs, brachial systolic BP and hfPWV at 15 min were higher than at baseline (P < .05). An acute increase of hfPWV in the HTs was significant (P = .025) after adjustment for total cholesterol, time-dependent HR, and brachial mean arterial pressure, but acute changes of other PWVs lost statistical significance. CONCLUSIONS: Cigarette smoking acutely increases aortic stiffness and BP in male smokers with hypertension, and the effects persist longer than in male smokers without hypertension.

Mechanism of enhanced cardiac function in mice with hypertrophy induced by overexpressed Akt.

Transgenic mice with cardiac-specific overexpression of active Akt (TG) not only exhibit hypertrophy but also show enhanced left ventricular (LV) function. In 3-4-month-old TG, heart/body weight was increased by 60% and LV ejection fraction was elevated (84 +/- 2%, p < 0.01) compared with nontransgenic littermates (wild type (WT)) (73 +/- 1%). An increase in isolated ventricular myocyte contractile function (% contraction) in TG compared with WT (6.1 +/- 0.2 versus 3.5 +/- 0.2%, p < 0.01) was associated with increased Fura-2 Ca2+ transients (396 +/- 50 versus 250 +/- 24 nmol/liter, p < 0.05). The rate of relaxation (+dL/dt) was also enhanced in TG (214 +/- 15 versus 98 +/- 18 microm/s, p < 0.01). L-type Ca2+ current (ICa) density was increased in TG compared with WT (-9.0 +/- 0.3 versus 7.2 +/- 0.3 pA/pF, p < 0.01). Sarcoplasmic reticulum Ca2+ ATPase 2a (SERCA2a) protein levels were increased (p < 0.05) by 6.6-fold in TG, which could be recapitulated in vitro by adenovirus-mediated overexpression of Akt in cultured adult ventricular myocytes. Conversely, inhibiting SERCA with either ryanodine or thapsigargin affected myocyte contraction and relaxation and Ca2+ channel kinetics more in TG than in WT. Thus, myocytes from mice with overexpressed Akt demonstrated enhanced contractility and relaxation, Fura-2 Ca2+ transients, and Ca2+ channel currents. Furthermore, increased protein expression of SERCA2a plays an important role in mediating enhanced LV function by Akt. Up-regulation of SERCA2a expression and enhanced LV myocyte contraction and relaxation in Akt-induced hypertrophy is opposite to the down-regulation of SERCA2a and reduced contractile function observed in many other forms of LV hypertrophy.

Altered excitation-contraction coupling in myocytes from remodeled myocardium after chronic myocardial infarction.

Following myocardial infarction (MI), the left ventricle undergoes progressive dilatation and eccentric hypertrophy, i.e., remodeling, which is greater in the adjacent than the remote region. The cellular mechanisms underlying these regional differences were studied. One (n=5) and 8 weeks (n=8) after anteroapical MI in sheep, cardiac myocytes were isolated from the adjacent and remote regions. At 8 weeks after MI, myocyte function in the remote region was not different from values either in sham controls (n=3) or animals 1 week after MI. At 8 weeks after MI, myocyte contractile function (% contraction) was decreased, P<0.01, in the adjacent region (6.4+/-0.4%), as compared with the remote region (8.8+/-0.5%) and was associated with decreased amplitude of Ca(2+)transients (adjacent, 0.69+/-0.09 v remote, 1.08+/-0.20, P<0.05) and L-type Ca(2+)current density (adjacent, 3.6+/-0.2 v remote, 4.8+/-0.2 pA/pF, P<0.05). Relaxation was also impaired significantly in myocytes from the adjacent region, associated with decreased protein levels of SERCA2a. The myocytes were hypertrophied more in the adjacent region than the remote region. Furthermore, focal areas of central myofibrillar lysis and increased glycogen deposition were observed in the adjacent region. These results indicate that impaired excitation-contraction coupling underlies dysfunction of myocytes from the adjacent non-infarcted myocardium after chronic MI, even in the absence of heart failure. Hypertrophy is implicated as the mechanism, since these changes were noted at 8 weeks, but not at 1 week after MI.