Effect of High Temperature on Walking among Residents of Rural and Urban Communities

PURPOSE

This study aimed to establish the association between high temperature and walking among residents of rural and urban areas.

MATERIALS AND METHODS

This cross-sectional study used data from the Korea Meteorological Administration and the 2018 Community Health Survey to confirm the association between temperature and walking practice. The dependent variable was walking practice. Walking practice was considered if the participants walked for more than 30 minutes a day or more than 5 days a week. The independent variable was the daily maximum temperature (℃) for the preceding 7 days, calculated from the survey date of each participant. A multilevel analysis was conducted to simultaneously consider the individual- and neighborhood-level variables that could affect determining the association between daily maximum temperatures and walking practice.

RESULTS

When the daily maximum temperature increased by 1℃, the odds ratio of walking practice decreased to 0.95 (95% confidence interval 0.94-0.97) in rural areas. In contrast, it decreased to 0.98 (95% confidence interval 0.97-1.00) in urban areas, considering both individual- and neighborhood-level factors. Individual- and neighborhood-level determinants of walking practice in rural areas, including educational attainment, marital status, driving a car, subjective health, depression, and meeting neighbors and friends, were confirmed.

CONCLUSION

This study confirmed that increased temperature led to more decrease in physical activity levels in rural areas than in urban areas. Physical and environmental approaches to avoid heat are needed to maintain and promote physical activity, since temperatures can reduce physical activity during the hot summer months.

Comparative effectiveness of early rhythm control versus rate control for cardiovascular outcomes according to sex in patients with atrial fibrillation

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health & Welfare, Republic of Korea

Background

Rhythm control is associated with better cardiovascular outcomes than usual care among patients recently diagnosed with atrial fibrillation (AF). However, there are limited data on the outcomes of AF ablation according to sex. The purpose of this study was to evaluate gender differences in the effects of early rhythm control compared to rate control on the primary composite outcome of cardiovascular death, ischaemic stroke, hospitalisation for heart failure (HF), or myocardial infarction.

Methods

We conducted a retrospective population-based cohort study including 22635 patients with AF newly treated with rhythm control (antiarrhythmic drugs or ablation) or rate control in 2011-2015 from the Korean National Health Insurance Service database. Propensity overlap weighting was used.

Results

Among patients with early AF treatment (initiated within 1 year since diagnosis), compared with rate control, rhythm control was associated with a similar lower risk of the primary composite outcome both women (weighted incidence rate per 100 person-years: 8.68 in rhythm control vs. 10.3 in rate control; hazard ratio [HR] 0.79, 95% confidence interval [CI] 0.69 to 0.90; P<0.001) and men (weighted incidence rate per 100 person-years: 6.33 in rhythm control vs. 8.32 in rate control; HR 0.77, 95% CI 0.67 to 0.88; P<0.001). However, the effective initiation time for rhythm control therapy was within 6 and 11 months after AF diagnosis in female and male patients, respectively. Moreover, the effective times for other outcomes were different between genders (hospitalization for HF; female within 2 months, male within 9 months/ ischemic stroke; female within 11 months, male immediately).

Conclusions

Early initiation of rhythm control was associated with a lower risk of primary outcome in both genders. However, the effective rhythm control treatment initiation time for primary outcome, stroke and HF-related admission was different in both genders. For rhythm control treatment to be effective, women should start treatment earlier than men.

Early mortality and complications associated with catheter ablation of atrial fibrillation: analysis of the entire procedure in Korea from 2007 to 2016

Funding Acknowledgements

Type of funding sources: None.

Background

There is limited data regarding the early mortality and adverse outcomes from catheter ablation of atrial fibrillation (AF) in Korea. The aim of this study was to examine the early mortality and frequency of adverse outcomes associated with AF catheter ablation from 2006 to 2016 in Korea.

Methods

From 2006 to 2016 in the Korean National Health Insurance Service database, 11,893 individuals underwent catheter ablation for AF. We investigated the frequency of complications and early mortality associated with AF ablation and comorbidities that led to adverse outcomes after AF ablation.

Results

Out of all 11,893 procedures, early mortality occurred in 38 cases (0.32%). Annual trends in AF procedural complications occurring during index admission for AF ablation decreased from 9.25% in 2006 to 6.49% in 2016 (P for trend = 0.004). The early mortality rate after AF ablation had remained unchanged between 2006 and 2016. After adjustment for age, comorbidities, and medication, procedural complications (adjusted odds ratio[aOR]: 16.1; P < 0.001), age (aOR: 1.25; P = 0.024), history of hemorrhagic stroke (aOR: 4.74; P = 0.019), and less experience with AF ablation of the hospital (aOR: 2.85; P = 0.024) were associated with early mortality. Among procedural complications, atrioesophageal fistula (aOR: 199.8; P < 0.001), access site complications (aOR: 6.08; P = 0.005), complete heart block (aOR: 11.3; P = 0.029), pneumothorax (aOR: 62.0; P < 0.001), and procedure related pneumonia (aOR: 39.0; P < 0.001) were associated with early mortality.

Conclusions

Procedural complications, history of hemorrhagic stroke, and less experience with AF ablation of the hospital were predictors of early mortality. Out of all complications, atrioesophageal fistual, procedure related pneumonia, and in-hospital stroke were related to early mortality. Adequate management of complications may contribute to reducing the number of early mortalty rates following AF ablation. Abstract Figure. Trend of early mortality after ablation

Clinicopathological and ultrasound features of endometrial cancer in postmenopausal women: a retrospective study in a single institute in South Korea

Introduction

endometrial cancer is the most common type of cancer in the female genital tract. Most patients are diagnosed during postmenopausal periods. This study aimed to investigate the demographic characteristics as well as cutoff value of endometrial thickness and ultrasound characteristics of endometrial cancer in postmenopausal patients.

Methods

we retrospectively analyzed 244 postmenopausal women who underwent endometrial sampling from February 2016 to December 2019. Information of patients was obtained through medical records. The patients were divided into two groups according to histopathological results. Group A included patients with endometrial cancer and group B included patients with non-malignant lesions. Data were summarized based on demographic and ultrasound characteristics.

Results

hypertension and history of endometrial hyperplasia were associated with the incidence of endometrial cancer in this study. Endometrial cancer was diagnosed in all ranges when the endometrial thickness was ≥5 mm. Endometrial fluid collection, with increased endometrial thickness, was a risk factor associated with endometrial cancer.

Conclusion

regardless of symptoms and risk factors, endometrial histological confirmation in postmenopausal women should be conducted immediately if endometrial abnormalities such as an endometrial thickness ≥5 mm or endometrial fluid collection are detected by transvaginal ultrasound.

208Effect of hypertension duration and systolic blood pressure on dementia in patients with atrial fibrillation

Background

Atrial fibrillation (AF) is associated with a higher risk for cognitive impairment and dementia, with or without a history of clinical stroke. There are a paucity of data on the associations of hypertension duration and blood pressure (BP) level with risk of dementia in patients with AF.

Purpose

We examined associations of duration of hypertension and secondly, systolic blood pressure (SBP) levels with incidence of dementia among patients with AF.

Methods

We enrolled a total 196,388 patients aged ≥50 years who were newly diagnosed as AF and undergoing hypertension treatment from the Korean National Health Insurance Service database (2005–2016). Starting from AF diagnosis, participants were followed up until the date of dementia, death, or December 31, 2016. To incorporate the effect of BP level and hypertension duration changes over time on dementia incidence, we constructed time-updated multivariable Cox models in which BP levels and hypertension duration were updated at each participants' regular national health examination visits (at 0–7 years of follow-up). Similarly, age, BP medications, and health-related behaviors were included as time-varying covariates in these models.

Results

During 1,016,744 person-years of follow-up, there were 32,692 dementia events. A cubic spline curve using continuous hypertension duration measures suggested a linear association between increase of hypertension duration and dementia risk. One-year increase of hypertension duration increased the adjusted risk of dementia with a hazard ratio (HR) of 1.17 [95% confidence interval (CI) 1.13–1.22]. In patients with hypertension duration <6 years, SBP of ≥140 mmHg was significantly associated with higher dementia risk, compared to SBP of <130 mmHg (in patients with hypertension duration <3 years: adjusted HR 1.08, 95% CI 1.01–1.16; and in those with 3 ≤ hypertension duration <6 years: adjusted HR 1.13, 95% CI 1.07–1.20), whereas no significant association between SBP and dementia risk in those with hypertension duration ≥6 years.

SBP and dementia in different duration

Conclusion

In patients with AF, the increase of hypertension duration was strongly associated with increased risk of dementia. Uncontrolled SBP was also associated with higher dementia risk. But, this effect of SBP might be attenuated in patients with longer hypertension duration. These findings suggest more emphasis needed on BP control in AF patients with earlier phase of hypertension (duration <6 years).

Acknowledgement/Funding

The Korean Ministry of Education, Science and Technology (NRF-2017R1A2B3003303) and the Korean Ministry of Health & Welfare (HI16C0058, HI15C1200)

64Risk of dementia in patients treated with non-vitamin k antagonist oral anticoagulant or warfarin for nonvalvular atrial fibrillation

Background

Evidence is accumulating that use of oral anticoagulants (OACs) decreases the risk of dementia in patients with atrial fibrillation (AF), but it is unclear if there is a difference between non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin in protecting against dementia.

Purpose

To compare the risk of dementia between patients taking either NOAC or warfarin using a nationwide cohort data covering the entire Korean population.

Methods

Using the Korean national health insurance service database, 68,984 new OAC users with non-valvular AF aged ≥50 years and no prior diagnosis of dementia were identified during the period of 2013–2016 (39,687 NOAC users and 29,297 warfarin users). Starting from OAC initiation, participants were followed up until the date of dementia, death, or December 31, 2016. We compared the rates of dementia in 1:1 propensity score-matched cohorts of NOAC (n=18,925) and warfarin users (n=18,925).

Results

During the 52,259 person-years of follow-up, there were 2,750 dementia events. Use of NOAC was associated with significant lower risk of dementia [hazard ratio (HR) 0.75, 95% confidence interval (CI) 0.69–0.81], compared with warfarin. The risk reduction was prominent for vascular dementia (HR 0.60, 95% CI 0.52–0.71), whereas there was no significant difference in the risk of Alzheimer dementia (HR 0.92, 95% CI 0.83–1.02). Restricting the analyses to patients with no stroke diagnosis prior to OAC initiation (primary prevention) showed no significant difference between NOAC and warfarin in any types of dementia, but in the subgroup with prior stroke (secondary prevention), NOAC significantly reduced the risk of overall (HR 0.70, 95% CI 0.63–0.78) and vascular dementia (HR 0.59, 95% CI 0.49–0.69).

Subgroup analysis according to stroke Hx Patient N Overall dementia Alzheimer dementia Vascular dementia HR (95% CI) P for interaction HR (95% CI) P for interaction HR (95% CI) P for interaction Total 37,850 0.75 (0.69–0.81) 0.92 (0.83–1.02) 0.60 (0.52–0.71) Without prior stroke 24,773 0.90 (0.78–1.05) 0.948 0.98 (0.83–1.15) 0.235 0.85 (0.56–1.28) 0.863 With prior stroke 13,077 0.70 (0.63–0.78) 0.90 (0.79–1.03) 0.59 (0.49–0.69) CI, confidence interval; HR, hazard ratio.

KM curves of dementia incidence

Conclusion

In this propensity-weighted nationwide cohort of non-valvular AF patients, NOAC was associated with reduced risk of dementia, compared with warfarin. This association was the most pronounced for vascular dementia in patients with prior stroke.

Acknowledgement/Funding

The Korean Ministry of Education, Science and Technology (NRF-2017R1A2B3003303) and the Korean Ministry of Health & Welfare (HI16C0058, HI15C1200)

P345Catheter ablation for atrial fibrillation is associated with lower incidence of stroke, major bleeding and death: data from Korean health registries

Background

Compared with antiarrhythmic drug therapy, catheter ablation of AF reduces the number of AF episodes, prolongs the time in sinus rhythm, and improves quality of life. However, it is still unclear if catheter ablation for atrial fibrillation (AF) affects the prognosis or merely is a symptomatic treatment. Our objective was to compare long-term outcome regarding stroke, major bleeding and death in AF patients with and without ablation, and in relation to long-term exposure to anticoagulants.

Methods

We identified all 800,084 patients with a diagnosis of AF from 2006 to 2015 in the Korean national health insurance service database. During a 10-year period, 10,979 AF ablations were performed among 9,768 individuals. Propensity scores for the likelihood of AF ablation were obtained by logistic regression. Propensity score (PS) matching was used to construct two cohorts of equal size (n=9,768) with similar characteristics in 16 dimensions.

Results

Patients who had undergone catheter ablation were younger (57.2 vs. 65.6 years, P<0.001) and healthier (mean CHA2DS2-VASc scores 2.5±1.7 vs. 3.6±2.1, P<0.001) than other patients with AF. Mean follow-up was 5.5±3.1 years. After propensity score matching, in the ablated group, 472 patients suffered ischemic stroke/systemic embolism (SE) compared with 1,682 in the matched non-ablated (annual rates 2.92 vs. 1.10%, P<0.001). Major bleeding occurred in 439 and 1,219 patients in ablated and non-ablated (annual rates 2.07 vs. 1.01%, P<0.001). A total of 306 ablated and 1,439 non-ablated patients died (annual rates 2.31 vs. 0.69%, P<0.001). After multivariable adjustments, catheter ablation was associated with lower risk of ischemic stroke [hazard ratio (HR) 0.51, 95% confidence interval (CI) 0.38–0.67), lower risk of major bleeding (HR 0.65, 95% CI 0.57–0.75) and with lower mortality risk (HR 0.39, 95% CI 0.34–0.46). The reduction of stroke/SE and mortality was observed after AF ablation regardless thromboembolic risk. Major bleeding was reduced only among patients with CHA2DS2-VASc score ≥2 (HR 0.70, 95% CI 0.59–0.84).

Conclusion

We found a strong association between ablation and survival. Ablation may be associated with lower incidence of ischemic stroke and major bleeding in patients with AF. The reduction of stroke/SE and mortality was observed regardless thromboembolic risk after AF ablation. But the risk of major bleeding was reduced only in patients with high thromboembolic risk factors.

P1027The risk of dementia and catheter ablation for atrial fibrillation: a nationwide cohort study

Background

Atrial fibrillation (AF) is associated with all forms of dementia, including Alzheimer's disease. Catheter ablation of AF reduces the number of AF episodes, prolongs the time in sinus rhythm, and improves quality of life. However, it is still unclear if catheter ablation for AF improve cognitive function and prevent dementia. Our objective was to compare long-term outcome regarding dementia and type of dementia in AF patients with and without ablation, and about long-term exposure to anticoagulants.

Methods

We identified all 801,701 patients with a diagnosis of AF from 2006 to 2015 in the Korean national health insurance service database. During ten years, 10,979 AF ablations were performed among 9,768 individuals. Propensity scores for the likelihood of AF ablation were obtained by logistic regression. Propensity score (PS) matching was used to construct two cohorts of equal size (n=9,768) with similar characteristics in 16 dimensions.

Results

Patients who had undergone catheter ablation were younger (57.2 vs. 65.6 years, P<0.001) and healthier (mean CHA2DS2-VASc scores 2.5±1.7 vs. 3.6±2.1, p<0.001) than other patients with AF. Mean follow-up was 5.5±3.1 years. After propensity score matching, in the ablated group, 184 patients suffered dementia compared with 650 in the matched non-ablated (annual rates 0.42 vs. 1.08%, P<0.001). While a total of 134 ablated and 379 non-ablated patients had Alzheimer disease (annual rates 0.31 vs. 0.62%, p<0.001), 40 ablated and 191 non-ablated patients had vascular disease (annual rates 0.09 vs. 0.31%, p<0.001). After multivariable adjustments, catheter ablation was associated with lower risk of dementia (hazard ratio [HR] 0.46, 95% confidence interval [CI] 0.37–0.58), lower risk of Alzheimer disease (HR 0.61, 95% CI 0.46–0.79) and lower risk of vascular dementia (HR 0.27, 95% CI 0.19–0.38). Although the reduction of dementia and Alzheimer disease was observed after AF ablation regardless of thromboembolic risk, vascular dementia was reduced only among patients with CHA2DS2-VASc score ≥2 (HR 0.29, 95% CI 0.20–0.42).

The risk of dementia, RFCA vs. no-RFCA Type Propensity score matched ablation group vs. no ablation group adjusted HR (95% CI) P-value Overall dementia 0.46 (0.37–0.58) <0.001 Alzheimer dementia 0.61 (0.46–0.79) <0.001 Vascular dementia 0.27 (0.19–0.38) <0.001

Conclusion

Ablation may be associated with a lower incidence of dementia and both type of dementia in patients with AF. This finding appears more pronounced in patients with high thromboembolic risk factors.

Clinicopathologic characteristics and treatment patterns of pelvic organ prolapse in South Korea

Introduction

We investigated the clinicopathologic features, method of treatment, and complications related to the conservative treatment and surgical treatment of patients with pelvic organ prolapse (POP).

Methods

We retrospectively analyzed 288 patients who were diagnosed with POP from January 2007 to December 2017. The patients were divided into two groups according to the treatment method (Group A received conservative treatment and Group B received surgical treatment). The patients' clinicopathologic characteristics, treatment method, and post-treatment complications were compared between groups A and B.

Results

Of the total 288 patients, 83 and 205 patients were assigned to Groups A and B, respectively. The most common symptom was a bearing-down sensation (n = 205, 71.2%), which was reported in 51 (61.4%) and 154 (75.1%) patients from Groups A and B, respectively. Among underlying diseases, hypertension was the most common in both groups (40 and 102 patients in Groups A and B, respectively). Overall, 205 patients underwent surgery, 23 underwent vaginal pessary, and 60 performed pelvic floor muscle exercises. The incidence of treatment-related complications was not significantly different between Groups A and B (13.3% vs. 17.6%, p = 0.37). Perioperative complications were noted in 20 (17.8%) patients and vault prolapse requiring subsequent surgery was noted in 16 (14.1%) patients.

Conclusion

As surgical treatment is associated with recurrence and complications, conservative treatment methods can be initially considered for patients with POP. In this study, there was no difference in the incidence of complications between surgical and conservative treatments. Thus, if required, surgical treatment can be safely performed in patients with POP.

Application of cold intolerance symptom severity questionnaire among vibration-exposed workers as a screening tool for the early detection of hand-arm vibration syndrome: a cross-sectional study

Background

The detection rate of hand-arm vibration syndrome (HAVS) is very low in South Korea compared with other countries. The absence of uniform consensus and guidelines for diagnosing HAVS has been presumed to be one of the reasons. The HAVS has various manifestations including cold intolerance and its severity can be measured using the cold intolerance symptom severity (CISS) questionnaire. This study aimed to determine whether the CISS questionnaire, being used as a screening tool, can aid in the early detection of HAVS.

Methods

A total of 76 male workers with vibration-induced symptoms were enrolled as the final study participants. To compare the CISS score of healthy individuals, 41 men who had never been exposed to local vibration were included in the study. In addition to the former medical questionnaire, the participants answered the CISS questionnaire. A statistical analysis was conducted to identify the association of CISS scores with vibration induced symptom and to determine its cut off value.

Results

The reliability of the CISS questionnaire was proven to be good, with a total Cronbach’s alpha of 0.922. The mean CISS score of the exposed group increased in every vascular stage [stage 0 = 42.6 (18.5); stage 1 = 59.4 (14.1); and over stage 2 = 60.2 (21.6)]. They were significantly higher than that of the non-exposed group. The result was fairly consistent with those in the sensorineural stage. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under curve (AUC) of 30 were 88.5, 65.3, 76.1, 82.1 and 0.769, respectively. From the result of logistic regression, the adjusted odds ratio of both components increased by the CISS score grouped by 30s.

Conclusions

The self-reported CISS questionnaire, used to measure the degree of cold intolerance, showed high agreement with the Stockholm classification of HAVS. Hence, we recommend the use of this questionnaire to assess the level of cold intolerance among vibration-exposed workers and detect individuals who are at risk of vibration-induced impairment with a cutoff value of 30.

Trial registration

IRB No. 2018–07–040-001. Registered on 4 September 2018.

Influence of Physical and Musculoskeletal Factors on Occupational Injuries and Accidents in Korean Workers Based on Gender and Company Size

Though the overall incidence of occupational injuries and accidents has decreased, they continue to happen. Many associated factors are known and managing them with limited resources is difficult. This study evaluates related risk factors and prioritizes their management for reducing occupational injuries and accidents at the workplace. We used data from the 4th Korean Working Condition Survey conducted by the Korea Occupational Safety Health Research Institute from June to September 2014. A total of 14,381 persons (9776 men, 4605 women) were selected; t-test, chi-square test, and logistic regression analyses were performed to analyze data. The influence of physical (vibration, noise, abnormal temperature) and musculoskeletal (awkward posture, handling of heavy objects, repetitive tasks) factors was compared according to gender and company size. The risk of occupational injuries and accidents among men was related to musculoskeletal factors and vibration in companies with “under 50” employees and with awkward posture, vibration, and noise in companies with “50 or above” employees; however, among women in companies with “under 50” employees, it was associated with only vibration. Although we evaluated only a few risk factors, prioritizing them based on gender and company size has provided new valuable information.

Clinicopathologic Characteristics and Causes of Postmenopausal Bleeding in Older Patients

Background

This study aimed to reveal the clinicopathologic features and causes of bleeding in older patients with postmenopausal bleeding (PMB) and to investigate the correlation between the ultrasonographic findings and etiology of PMB.

Methods

We retrospectively analyzed the causes and clinical characteristics of PMB in 498 patients who were diagnosed between January 2007 and December 2017. The population with PMB was divided into 2 groups according to age: Group A (n=204) included individuals more than 65 years of age and group B (n=294) included those less than 65 years of age. Clinical characteristics such as age, parity, underlying conditions, previous surgical history, and previous menopausal hormone therapy were compared between the groups. Cervical cytology testing and transvaginal ultrasonography were performed in all patients with PMB. Endometrial biopsy was performed in all cases of endometrial thickness ≥5 mm.

Results

We examined 498 patients with PMB. In group A, atrophic endometrium (n=125, 61.27%) was the most common cause of PMB. Twenty-three patients had gynecological malignancy (cervical cancer: n=12, 5.88%; endometrial cancer: n=8, 3.42%; ovarian cancer: n=3, 1.46%), and 30 patients had benign gynecological disease (endometrial polyp: n=10, 4.90%; submucosal myoma: n=6, 2.94%; uterine prolapse: n=7, 3.42%; cervical dysplasia; n=5, 2.45%; cervical polyp: n=2, 0.98%). Forty patients had endometrial thickness ≥5 mm. Eight patients were diagnosed with endometrial cancer. All cases of endometrial cancer were diagnosed with endometrial thickness >10 mm.

Conclusion

Atrophic endometrium was the most common cause of PMB in both groups, and approximately 12% of cases were associated with gynecological malignancy in older patients.

Comparison of a 10-Year Cumulative Age-Standardized Incidence Rate of Lung Cancer among Metropolitan Cities in Korea (During the 2000⁻2009 Period): Review of Occupational and Environmental Hazards Associated with Lung Cancer

In Korea, lung cancer is a common cancer, and has the highest mortality rate in both males and females. Approximately 80% of lung cancer is due to smoking, and the remaining cases are known to be due to genetic factors, history of respiratory disease, infection, diet, and occupational and environmental factors. Since the occupational and environmental hazards may differ from region to region, the lung cancer risk may differ too. To identify this, we selected seven metropolitan cities, and compared occupational and environmental hazards. Furthermore, we calculated smoking rate adjusted standardized rate ratio (ratio of 10-year cumulative age-standardized incidence rate of lung cancer during the 2000⁻2009 period at target region versus reference region) to compare the regional lung cancer risk. The result showed that the emissions and concentrations of air pollutant were higher in high-risk regions, and the risk of lung cancer was significantly elevated in such area. In this study, we simultaneously consider the cumulative incidence, age-standardization and smoking rate adjustment. Therefore, we can conclude that the validity of the finding of this study is higher than that of past studies. In conclusion, the occupational and environmental hazards have an effect on lung cancer.

Low Income as a Vulnerable Factor to the Effect of Noise on Insomnia

OBJECTIVE

The present study aimed to examine the potential mediating effect of income level on the association between noise exposure and insomnia.

METHODS

706 individuals were evaluated in conjunction with 2014 noise map data from Seoul, South Korea. Cross-sectional analysis was performed to examine differences in noise level according to household income, while three separate logistic regression models were used to examine factors influencing insomnia. Odds ratios (ORs) were calculated after adjusting for depression, anxiety, auditory acuity and noise sensitivity in the first model. Analyses were adjusted for sociodemographic variables in the second model, lifestyle factors and medical illnesses in the third model.

RESULTS

Noise level was significantly associated with an increased risk of insomnia in the low-income group, although no such association was observed in the high-income group. Groups exposed to >60 dB of noise (Lden; day-evening-night equivalent) exhibited a 1.79-fold increase in the incidence of insomnia relative to those exposed to <50 dB. The result was significant after adjusting sociodemographic variables, although not significant when adjusted for lifestyle factors and medical illnesses.

CONCLUSION

Individuals with low income may be more vulnerable to the deleterious effects of noise exposure on health. Various aspects including income should be considered to ascertain the influence of noise on insomnia.

Environmental and Body Concentrations of Heavy Metals at Sites Near and Distant from Industrial Complexes in Ulsan, Korea

BACKGROUND

Industrial pollution may affect the heavy metal body burden of people living near industrial complexes. We determined the average concentrations of atmospheric heavy metals in areas close to and distant from industrial complexes in Korea, and the body concentrations of these heavy metals in residents living near and distant from these facilities.

METHODS

The atmospheric data of heavy metals (lead and cadmium) were from the Regional Air Monitoring Network in Ulsan. We recruited 1,148 participants, 872 who lived near an industrial complex ("exposed" group) and 276 who lived distant from industrial complexes ("non-exposed" group), and measured their concentrations of blood lead, urinary cadmium, and urinary total mercury.

RESULTS

The results showed that atmospheric and human concentrations of heavy metals were higher in areas near industrial complexes. In addition, residents living near industrial complexes had higher individual and combined concentrations (cadmium + lead + mercury) of heavy metals.

CONCLUSION

We conclude that residents living near industrial complexes are exposed to high concentrations of heavy metals, and should be carefully monitored.

The association between cadmium and lead exposure and blood pressure among workers of a smelting industry: a cross-sectional study

BACKGROUND

Lead and cadmium are harmful heavy metals that are used for a variety of occupational purposes. Considering their potentially hazardous effects on health, studies on the association between exposure to these two heavy metals and health disorders have been actively conducted. This study aimed to determine the association between blood lead and cadmium levels and blood pressure in workers exposed to lead and cadmium in a smelter.

METHODS

Nine hundred and sixty-three male workers who worked in a smelter, and underwent medical examinations at the Ulsan University Hospital between January 1 and December 31, 2014, were selected as participants. Among them, 310 subjects whose data on height, weight, blood pressure, fasting blood glucose, lipid profile, and blood lead and cadmium levels were available and who answered the questionnaire were selected as the final participants. We investigated the drinking habit, smoking status, exercise adequacy, and family history of hypertension of these workers using formal questionnaires. A statistical analysis was conducted using Student's t-test, analysis of variance, and linear or logistic regression.

RESULTS

The association between blood lead and cadmium levels and blood pressure was analyzed through statistical adjustment of the risk factors of hypertension. Results showed an association between blood cadmium level and blood pressure elevation. However, blood lead level was found to be not correlated with blood pressure elevation.

CONCLUSIONS

This study shows the association between blood cadmium level and systolic blood pressure (SBP) and diastolic blood pressure (DBP) elevation.

TRIAL REGISTRATION

IRB No. 2017-03-037. Retrospectively Registered 30 March 2017.

Microglia: The Effector Cell for Reconstitution of the Central Nervous System following Bone Marrow Transplantation for Lysosomal and Peroxisomal Storage Diseases

Treatment and potential cure of lysosomal and peroxisomal diseases, heretofore considered fatal, has become a reality during the past decade. Bone marrow transplantation, (BMT), has provided a method for replacement of the disease-causing enzyme deficiency. Cells derived from the donor marrow continue to provide enzyme indefinitely. Several scores of patients with diseases as diverse as metachromatic leukodystrophy, adrenoleukodystrophy, globoid cell leukodystrophy, Hurler syndrome (MPS I-H), Maroteaux-Lamy (MPS VI) Gaucher disease, and fucosidosis have been successfully treated following long-term engraftment. Central nervous system (CNS) manifestations are also prevented or ameliorated in animal models of these diseases following engraftment from normal donors. The microglial cell system has been considered to be the most likely vehicle for enzyme activity following bone marrow engraftment. Microglia in the mature animal or human are derived from the newly engrafted bone marrow. Graft-v-host disease activation of the microglia is also of importance. This article will summarize some of the pertinent literature relative to the role of microglia in such transplant processes.

The responses of subjective feeling, task performance ability, cortisol and HRV for the various types of floor impact sound: a pilot study

BACKGROUND

Recently, noise coming from the neighborhood via floor wall has become a great social problem. The noise between the floors can be a cause of physical and psychological problems, and the different types of floor impact sound (FIS) may have the different effects on the human's body and mind. The purpose of this study is to assess the responses of subjective feeling, task performance ability, cortisol and HRV for the various types of floor impact.

METHODS

Ten men and 5 women were enrolled in our study, and the English listening test was performed under the twelve different types of FIS, which were made by the combinations of bang machine (B), tapping machine (T), impact ball (I) and sound-proof mattress (M). The 15 subjects were exposed to each FIS for about 3 min, and the subjective annoyance, performance ability (English listening test), cortisol level of urine/saliva and heart rate variability (HRV) were examined. The sound pressure level (SPL) and frequency of FIS were analyzed. Repeated-measures ANOVA, paired t-test, Wilcoxon signed rank test were performed for data analysis.

RESULTS

The SPL of tapping machine (T) was reduced with the soundproof mattress (M) by 3.9-7.3 dBA. Impact ball (I) was higher than other FIS in low frequency (31.5-125 Hz) by 10 dBA, and tapping machine (T) was higher than other FIS in high frequency (2-4 k Hz) by 10 dBA. The subjective annoyance is highest in the combination of bang machine and tapping machine (BT), and next in the tapping machine (T). The English listening score was also lowest in the BT, and next in T. The difference of salivary cortisol levels between various types of FIS was significant (p = 0.003). The change of HRV parameters by the change of FIS types was significant in some parameters, which were total power (TP) (p = 0.004), low frequency (LF) (p = 0.002) and high frequency (HF) (p = 0.011).

CONCLUSIONS

These results suggest that the human's subjective and objective responses were different according to FIS types and those combinations.

Noise sensitivity, rather than noise level, predicts the non-auditory effects of noise in community samples: a population-based survey

BACKGROUND

Excessive noise affects human health and interferes with daily activities. Although environmental noise may not directly cause mental illness, it may accelerate and intensify the development of latent mental disorders. Noise sensitivity (NS) is considered a moderator of non-auditory noise effects. In the present study, we aimed to assess whether NS is associated with non-auditory effects.

METHODS

We recruited a community sample of 1836 residents residing in Ulsan and Seoul, South Korea. From July to November 2015, participants were interviewed regarding their demographic characteristics, socioeconomic status, medical history, and NS. The non-auditory effects of noise were assessed using the Center of Epidemiologic Studies Depression, Insomnia Severity index, State Trait Anxiety Inventory state subscale, and Stress Response Inventory-Modified Form. Individual noise levels were recorded from noise maps. A three-model multivariate logistic regression analysis was performed to identify factors that might affect psychiatric illnesses.

RESULTS

Participants ranged in age from 19 to 91 years (mean: 47.0 ± 16.1 years), and 37.9% (n = 696) were male. Participants with high NS were more likely to have been diagnosed with diabetes and hyperlipidemia and to use psychiatric medication. The multivariable analysis indicated that even after adjusting for noise-related variables, sociodemographic factors, medical illness, and duration of residence, subjects in the high NS group were more than 2 times more likely to experience depression and insomnia and 1.9 times more likely to have anxiety, compared with those in the low NS group. Noise exposure level was not identified as an explanatory value.

CONCLUSIONS

NS increases the susceptibility and hence moderates there actions of individuals to noise. NS, rather than noise itself, is associated with an elevated susceptibility to non-auditory effects.

Effect of shift work on hypertension: cross sectional study

Background

The need of efficient resource management and full-time accessibility to resources has increased with the development of industry, resulting in the increase of shift workers. Previous researches of past decades show that there are various health effects on shift workers. However, the definition and the form of shift work have varied from each research and occupational harmful factors except for shift work have not been excluded completely in previous researches. Therefore, in this research, we tried to find out the effect of shift work focusing on the hypertension. To complement previously mentioned weakness of other researches, we performed our research on participants to whom we could minimize other risk factors excluding shift work.

Methods

This research examined 1,953 petrochemical plant male workers (shift work 1,075, day worker 878) who did medical checkup from 1st Jan. 2014 to 31th Dec. 2014 in a general hospital located in Ulsan, based on their medical records and questionnaires. With the questionnaire, we found out their basic information including age, social status, occupational history, and we took their physical measurements.

Results

Compared to day workers, shift workers’ odds ratio of developing hypertension was 1.31 (95% CI 0.98–1.75). After adjusting confounding variables, adjusted odds ratio for entire subjects was 1.51 (95% CI 1.11–2.06). Also, for subjects who were in continuous service for over 20 years, odds ratio was 1.51 (95% CI 1.08–2.11).

Conclusions

Shift workers had a higher chance of hypertension than day workers do. Particularly, the longer the workers work continuously, the risk of hypertension getting higher.

Influence of Transportation Noise and Noise Sensitivity on Annoyance: A Cross-Sectional Study in South Korea

Environmental noise is known to cause noise annoyance. Since noise annoyance is a subjective indicator, other mediators—such as noise sensitivity—may influence its perception. However, few studies have thus far been conducted on noise annoyance in South Korea that consider noise sensitivity and noise level simultaneously. The aim of this study was to evaluate the correlations between noise sensitivity or noise level and noise annoyance on a large scale in South Korea. This study estimated the level of noise exposure based on a noise map created in 2014; identified and surveyed 1836 subjects using a questionnaire; and assessed the impact of transportation noise and noise sensitivity on noise annoyance. The result showed that noise exposure level and noise sensitivity simultaneously affect noise annoyance, and noise sensitivity has a relatively larger impact on noise annoyance. In conclusion, when study subjects were exposed to a similar level of noise, the level of noise annoyance differed depending on the noise sensitivity of the individual.

Relationship of Transportation Noise and Annoyance for Two Metropolitan Cities in Korea: Population Based Study

Transportation noise is known to have negative impact on both public health and life quality. This study evaluated the relationship between transportation noise and annoyance levels, and also the difference of annoyance levels in two metropolitan cities based on epidemiologic surveys. Two thousand adult subjects living in Seoul and Ulsan were enrolled by stratified random sampling on the basis of noise maps from July 2015 to January 2016. Individual annoyance in accordance with transportation noise levels in two metropolitan cities were surveyed using an 11-point visual analog scale questionnaire. The results show that transportation noise level was significantly correlated with annoyance in both cities. Logistic regression analysis revealed that the risk of being ‘highly annoyed’ increased with noise level (L_dn, day-night average sound level) in both cities. After adjusting for age, residence period, sociodemographic factors (sex, education, marriage, income, alcohol, smoking, and exercise) and noise sensitivity, the risk of being ‘highly annoyed’ was increased with noise levels in both cities. In comparison to those of areas with noise levels below 55 dBA, the adjusted odds ratios of ‘highly annoyed’ for areas with 55–65 dBA and over 65 dBA were 2.056 (95% confidence interval [CI] 1.225–3.450), 3.519 (95% CI 1.982–6.246) in Seoul and 1.022 (95% CI 0.585–1.785), 1.704 (95% CI 1.005–2.889) in Ulsan, respectively. Based on the results of a population study, we showed that transportation noise levels were significantly associated with annoyance in adults. However, there were some differences between the two cities. In this study, there were differences in transportation noise between the two cities. Seoul has complex noise (traffic and aircraft), compared to single road traffic noise in Ulsan. Therefore, single and complex transportation noise may have different effects on annoyance levels.

Surface modulation and back reflection from foil targets irradiated by a Petawatt femtosecond laser pulse at oblique incidence

A significant level of back reflected laser energy was measured during the interaction of ultra-short, high contrast PW laser pulses with solid targets at 30° incidence. 2D PIC simulations carried out for the experimental conditions show that at the laser-target interface a dynamic regular structure is generated during the interaction, which acts as a grating (quasi-grating) and reflects back a significant amount of incident laser energy. With increasing laser intensity above 10¹⁸ W/cm² the back reflected fraction increases due to the growth of the surface modulation to larger amplitudes. Above 10²⁰ W/cm² this increase results in the partial destruction of the quasi-grating structure and, hence, in the saturation of the back reflection efficiency. The PIC simulation results are in good agreement with the experimental findings, and, additionally, demonstrate that in presence of a small amount of pre-plasma this regular structure will be smeared out and the back reflection reduced.

Comparisons of hearing threshold changes in male workers with unilateral conductive hearing loss exposed to workplace noise: a retrospective cohort study for 8 years

Background

The purpose of this study was to investigate hearing threshold changes of workers with unilateral conductive hearing loss who were exposed to workplace noise for 8-years.

Methods

Among 1819 workers at a shipyard in Ulsan, 78 subjects with an air-bone gap ≥10 dBHL in unilateral ears were selected. Factors that could affect hearing were acquired from questionnaires, physical examinations, and biochemistry examinations. Paired t-test was conducted to compare the hearing threshold changes over time between conductive hearing loss (CHL) ear and sensorineural hearing loss (SNHL) ear.

Results

The study included male subjects aged 48.7 ± 2.9, having worked for 29.8 ± 2.7 years. Hearing thresholds increased significantly in CHL ears and SNHL ears at all frequencies (0.5–6 kHz) during follow-up period (p < 0.05). The threshold change at 4 kHz was 3.2 dBHL higher in SNHL ears which was statistically significant (p < 0.05). When workers were exposed to noise levels of 85 dBA and above, threshold change at 4 kHz was 5.6 dBHL higher in SNHL ears which was statistically significant (p < 0.05). Among workers aged below 50, the threshold change values were lower in low-frequency (0.5–2 kHz) in SNHL ears, with a small range of changes, whereas in high-frequency (3–6 kHz), the range of changes was greater SNHL ears (p < 0.05). Among workers aged 50 and above, SNHL ears showed a wider range of changes in both high- and low-frequency areas (p < 0.05).

Conclusions

At high-frequencies, particularly at 4 kHz, the range of hearing threshold changes was lower in ears with conductive hearing loss than in contralateral ears. This is suggested as a protective effect against noise exposure.

A Study of Piezoelectric Field Related Strain Difference in GaN-Based Blue Light-Emitting Diodes Grown on Silicon(111) and Sapphire Substrates

We investigate the strain difference in InGaN/GaN multiple quantum wells of blue light-emitting diode (LED) structures grown on silicon(1 11) and c-plane sapphire substrates by comparing the strength of piezo-electric fields in MQWs. The piezo-electric fields for two LED samples grown on silicon and sapphire substrates are measured by using the reverse-bias electro-reflectance (ER) spectroscopy. The flat-band voltage is obtained by measuring the applied reverse bias voltage that induces a phase inversion in the ER spectra, which is used to calculate the strength of piezo-electric fields. The piezo-electric field is determined to be 1.36 MV/cm for the LED on silicon substrate and 1.83 MV/cm for the LED on sapphire substrate. The ER measurement results indicate that the strain-induced piezo-electric field is greatly reduced in the LED grown on silicon substrates consistent with previous strain measurement results by micro-Raman spectroscopy and high-resolution transmission electron microscopy.

Comparison of Strain in GaN-Based Blue Light-Emitting Diode Grown on Silicon(111) and Sapphire Substrates

We compare the strain states and device performances of GaN-based blue light-emitting diodes (LEDs) grown on Si(111) and sapphire substrates. The strain characteristics are investigated using micro-Raman spectroscopy and high-resolution transmission electron microscopy. These analyses reveal that GaN layer grown on Si has a residual tensile strain in contrast to a compressive strain for GaN on sapphire, and quantum wells (QWs) on GaN/Si experience reduced lattice mismatch than those of GaN/sapphire. When external quantum efficiencies of LED on sapphire and Si substrates are compared, the LED on Si shows better efficiency droop characteristics and this is attributed to a decrease in piezo-electric field strength in InGaN/GaN layers owing to reduced lattice mismatch.

The effects of different noise types on heart rate variability in men

PURPOSE

To determine the impact of noise on heart rate variability (HRV) in men, with a focus on the noise type rather than on noise intensity.

MATERIALS AND METHODS

Forty college-going male volunteers were enrolled in this study and were randomly divided into four groups according to the type of noise they were exposed to: background, traffic, speech, or mixed (traffic and speech) noise. All groups except the background group (35 dB) were exposed to 45 dB sound pressure levels. We collected data on age, smoking status, alcohol consumption, and disease status from responses to self-reported questionnaires and medical examinations. We also measured HRV parameters and blood pressure levels before and after exposure to noise. The HRV parameters were evaluated while patients remained seated for 5 minutes, and frequency and time domain analyses were then performed.

RESULTS

After noise exposure, only the speech noise group showed a reduced low frequency (LF) value, reflecting the activity of both the sympathetic and parasympathetic nervous systems. The low-to-high frequency (LF/HF) ratio, which reflected the activity of the autonomic nervous system (ANS), became more stable, decreasing from 5.21 to 1.37; however, this change was not statistically significant.

CONCLUSION

These results indicate that 45 dB(A) of noise, 10 dB(A) higher than background noise, affects the ANS. Additionally, the impact on HRV activity might differ according to the noise quality. Further studies will be required to ascertain the role of noise type.

Berberine induces apoptosis via ROS generation in PANC-1 and MIA-PaCa2 pancreatic cell lines

Pancreatic cancer is the fourth leading cause of cancer death. Gemcitabine is widely used as a chemotherapeutic agent for the treatment of pancreatic cancer, but the prognosis is still poor. Berberine, an isoquinoline alkaloid extracted from a variety of natural herbs, possesses a variety of pharmacological properties including anticancer effects. In this study, we investigated the anticancer effects of berberine and compared its use with that of gemcitabine in the pancreatic cancer cell lines PANC-1 and MIA-PaCa2. Berberine inhibited cell growth in a dose-dependent manner by inducing cell cycle arrest and apoptosis. After berberine treatment, the G1 phase of PANC-1 cells increased by 10% compared to control cells, and the G1 phase of MIA-PaCa2 cells was increased by 2%. Whereas gemcitabine exerts antiproliferation effects through S-phase arrest, our results showed that berberine inhibited proliferation by inducing G1-phase arrest. Berberine-induced apoptosis of PANC-1 and MIA-PaCa2 cells increased by 7 and 2% compared to control cells, respectively. Notably, berberine had a greater apoptotic effect in PANC-1 cells than gemcitabine. Upon treatment of PANC-1 and MIA-PaCa2 with berberine at a half-maximal inhibitory concentration (IC₅₀), apoptosis was induced by a mechanism that involved the production of reactive oxygen species (ROS) rather than caspase 3/7 activation. Our findings showed that berberine had anti-cancer effects and may be an effective drug for pancreatic cancer chemotherapy.

Clinical and angiographic features and stroke types in adult moyamoya disease

BACKGROUND AND PURPOSE

This study was conducted to elucidate the association between clinical and angiographic characteristics and stroke types in adult Moyamoya disease that has been rarely evaluated.

MATERIALS AND METHODS

We analyzed the clinical and radiologic data obtained from a retrospective adult Moyamoya disease cohort with acute strokes, which were classified into 7 categories: large-artery infarct, hemodynamic infarct, perforator infarct, deep intracerebral hemorrhage, lobar intracerebral hemorrhage, intraventricular hemorrhage, and SAH. With conventional angiography, which was performed in the hemispheres with acute strokes, the Suzuki angiographic stage, intracranial aneurysm, major artery occlusion, and collateral vessel development were confirmed within 1 month of stroke onset.

RESULTS

This study included 79 patients with acute ischemic stroke and 96 patients with acute hemorrhagic stroke. The angiographic stage had a strong tendency to be more advanced in the hemorrhagic than the ischemic patients (P = .061). Intracranial aneurysms were more frequently found in the hemorrhagic than ischemic or control hemispheres (P = .002). Occlusions of the anterior cerebral artery and development of fetal-type posterior cerebral artery were more frequently observed in the hemorrhagic than the ischemic (P = .001 and .01, respectively) or control hemispheres (P = .011 and .013, respectively). MCA occlusion (P = .039) and collateral flow development, including the ethmoidal Moyamoya vessels (P = .036) and transdural anastomosis of the external carotid artery (P = .022), occurred more often in the hemorrhagic than the ischemic hemispheres. Anterior cerebral artery occlusion occurred more frequently in patients with deep intracerebral hemorrhage or intraventricular hemorrhage than with lobar intracerebral hemorrhage (P = .009).

CONCLUSIONS

In adult Moyamoya disease, major artery occlusion and collateral compensation occurred more often in the hemorrhagic than in the ischemic hemispheres. Thus, anterior cerebral artery occlusion with or without MCA occlusion and intracranial aneurysms may be the main contributing factors to hemorrhagic stroke in adult patients with Moyamoya disease.

Normative data for neuromuscular assessment of the hand-arm vibration syndrome and its retrospective applications in Korean male workers

PURPOSE

The purpose of this study was to describe normative data for the neuromuscular assessments of the hand-arm vibration syndrome (HAVS) in Korean.

METHODS

Data for the vibrotactile perception threshold (VPT) at three frequencies (31.5, 125, and 250 Hz), the hand grip strength (HGS), the finger pinch strength (FPS), the finger tapping test, and the Purdue pegboard tests were collected from 120 male office workers aged 30-59 years with no prior history of regular use of handheld vibrating tools. The collected data were compared with the results of a similar study of shipbuilding workers in order to investigate the diagnostic utility of clinical test for HAVS.

RESULTS

The mean VPT values indicate that no significant differences were observed between the dominant and non-dominant hands or between the index and little fingers. The age group of 30s was highly sensitive to vibration input with a peak in sensitivity at 125 Hz among all age groups. In neuromuscular performance, dominant hands are usually more accurate, dexterous, and functionally quicker than non-dominant hands. The index finger was superior to the little finger in the finger tapping counts (p < 0.05). Also, FPS was greater in the index finger than in the middle finger (p < 0.05). The HGS of dominant hands was significantly stronger than that of non-dominant hands (p < 0.05). When the normative data were compared with the data of shipyard workers exposed to vibration, there were statistically significant differences in VPT and neuromuscular functions.

CONCLUSIONS

The current data can be used to evaluate HAVS in Korean male workers. Age is an important factor for VPT.

Relationship of cigarette smoking and hearing loss in workers exposed to occupational noise

Objectives

To investigate the effects of smoking on hearing loss among workers exposed to occupational noise.

Methods

From the results of a special workers health examination performed in 2011, we enrolled 8,543 subjects exposed to occupational noise and reviewed the findings. Using self-reported questionnaires and health examination results, we collected data on age, smoking status, disease status, height, weight, and biochemistry and pure tone audiometry findings. We divided the workers into 3 groups according to smoking status (non-smoker, ex-smoker, current smoker). Current smokers (n = 3,593) were divided into 4 groups according to smoking amount (0.05–9.9, 10–19.9, 20–29.9, ≥30 pack-years). We analyzed the data to compare hearing thresholds between smoking statuses using analysis of covariance (ANCOVA) after controlling for confounder effects.

Results

According to ANCOVA, the hearing thresholds of current smokers at 2 k, 3 k, and 4 kHz were significantly higher than that of the other groups. Multiple logistic regression for smoking status (reference: non-smokers) showed that the adjusted odds ratios of current smokers were 1.291 (95% confidence interval [CI]: 1.055–1.580), 1.180 (95% CI: 1.007–1.383), 1.295 (95% CI: 1.125–1.491), and 1.321 (95% CI: 1.157–1.507) at 1 k, 2 k, 3 k, and 4 kHz, respectively. Based on smoking amount, the adjusted odds ratios were 1.562 (95% CI: 1.013–2.408) and 1.643 (95% CI: 1.023–2.640) for the 10–19.9 and ≥30 pack-years group, respectively, at 1 kHz (reference: 0.05–9.9 pack-years). At 2 kHz, the adjusted odds ratios were increased statistically significantly with smoking amount for all groups. At all frequencies tested, the hearing thresholds of noise-exposed workers were significantly influenced by current smoking, in particular, the increase of hearing loss at low frequencies according to smoking amount was more prevalent.

Conclusions

Current smoking significantly influenced hearing loss at all frequencies in workers exposed to occupational noise, and heavier smoking influenced low-frequency hearing loss more greatly. There was a dose–response relationship between smoking amount and low-frequency hearing thresholds; however, this was not observed for high-frequency hearing thresholds. Therefore, well-designed prospective studies are needed to clarify the effects of smoking on the degree of hearing loss.

Laser-driven proton acceleration enhancement by nanostructured foils

Nanostructured thin plastic foils have been used to enhance the mechanism of laser-driven proton beam acceleration. In particular, the presence of a monolayer of polystyrene nanospheres on the target front side has drastically enhanced the absorption of the incident 100 TW laser beam, leading to a consequent increase in the maximum proton energy and beam charge. The cutoff energy increased by about 60% for the optimal spheres' diameter of 535 nm in comparison to the planar foil. The total number of protons with energies higher than 1 MeV was increased approximately 5 times. To our knowledge this is the first experimental demonstration of such advanced target geometry. Experimental results are interpreted and discussed by means of 2(1/2)-dimensional particle-in-cell simulations.

The efficacy of endovascular treatment of ruptured blood blister-like aneurysms using stent-assisted coil embolization

We report our experience with endovascular treatment and follow-up results of a ruptured blood blister-like aneurysm (BBA) in the supraclinoid internal carotid artery. We performed a retrospective review of ruptured blood blister-like aneurysm patients over a 30-month period. Seven patients (men/women, 2/5; mean age, 45.6 years) with ruptured BBAs were included from two different institutions. The angiographic findings, treatment strategies, and the clinical (modified Rankin Scale) and angiographic outcomes were retrospectively analyzed. All seven BBAs were located in the supraclinoid internal carotid artery. Four of them were ≥ 3 mm in largest diameter. Primary stent-assisted coiling was performed in six out of seven patients, and double stenting was done in one patient. In four patients, the coiling was augmented by overlapping stent insertion. Two patients experienced early re-hemorrhage, including one major fatal SAH. Complementary treatment was required in two patients, including coil embolization and covered-stent placement, respectively. Six of the seven BBAs showed complete or progressive occlusion at the time of late angiographic follow-up. The clinical midterm outcome was good (mRS scores, 0 -1) in five patients. Stent-assisted coiling of a ruptured BBA is technically challenging but can be done with good midterm results. However, as early re-growth/re-rupture remains a problem, repeated, short-term angiographic follow-up is required so that additional treatment can be performed as needed.

Intravenous Glycoprotein IIb/IIIa Inhibitor (Tirofiban) Followed by Low-Dose Intra-Arterial Urokinase and Mechanical Thrombolysis for the Treatment of Acute Stroke

We investigated the efficacy and safety of the combined use of IV tirofiban and IA urokinase and/or mechanical thrombolysis for treating acute stroke patients. Thirteen, consecutive patients treated with IV tirofiban and IA thrombolysis with mechanical and/or local IA urokinase infusion were evaluated retrospectively. The amount of time before the beginning of treatment, urokinase dose, recanalization rates, and symptomatic hemorrhage were analyzed. Clinical outcome measures were assessed on admission, at discharge (National Institute of Health Stroke scale [NIHSS]), and three months after the end of their treatment (modified Rankin Scale scores [mRS]). There were 11 patients with internal carotid or middle cerebral artery occlusion treated within six hours of the onset of symptoms and two patients with basilar artery occlusion treated within 12 hours of their symptom onset. The median NIHSS score on admission was 18. The median amount of time from symptom onset to IV tirofiban infusion was 135 minutes, and the median time from symptom onset to IA therapy was 180 minutes. The median dose of urokinase was 200,000 U. Recanalization (thrombolysis in myocardial infarction grade 2 or 3) was achieved in 11 patients. No procedure-related complications were observed. There was one symptomatic hemorrhage. At discharge, the mean NIHSS score was 6.6 (range, 0-15). Overall, at the time of the three-month follow-up the functional outcome was favorable (modified Rankin Scale score 0-2) in eight out of 13 (62%) patients. Death at 90 days occurred in two of the 13 (15%) patients. Combined IV tirofiban and IA thrombolysis with mechanical clot disruption seems to be a feasible treatment in acute stroke and may be successful in re-establishing vessel patency and result in a good functional outcome in patients with major cerebral arteries occlusions.

Liquid chromatography-tandem mass spectrometry determination of N-nitrosamines released from rubber or elastomer teats and soothers

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method as an alternative to a gas chromatography-thermal energy analyser (GC-TEA) method recommended by the European Committee on Standardization (CEN) was validated for the simultaneous determination of eight N-nitrosamines released into artificial saliva from rubber or elastomer teats and soothers. N-nitroso-dipropylamine-d₁₄ (NDPA-d₁₄) was used as internal standard for accurate quantification. The method was validated with relatively good analytical results, including sufficiently low limits of detection (0.1-2 µg kg⁻¹) of sample) and good linearity (r²> 0.99) throughout the studied concentration ranges. Intra- and inter-day precisions expressed with the relative standard deviation (RSD, %) were 3.4-8.0% and 4.4-11.3%, which were below the performance criteria based on one-half of the value derived from the Horwitz value. It was also found that the LC-MS/MS method is sufficiently rugged and successfully applicable to its routine analysis for the compliance test of Commission Directive 93/11/EEC.

Ion spectrometer composed of time-of-flight and Thomson parabola spectrometers for simultaneous characterization of laser-driven ions

An ion spectrometer, composed of a time-of-flight spectrometer (TOFS) and a Thomson parabola spectrometer (TPS), has been developed to measure energy spectra and to analyze species of laser-driven ions. Two spectrometers can be operated simultaneously, thereby facilitate to compare the independently measured data and to combine advantages of each spectrometer. Real-time and shot-to-shot characterizations have been possible with the TOFS, and species of ions can be analyzed with the TPS. The two spectrometers show very good agreement of maximum proton energy even for a single laser shot. The composite ion spectrometer can provide two complementary spectra measured by TOFS with a large solid angle and TPS with a small one for the same ion source, which are useful to estimate precise total ion number and to investigate fine structure of energy spectrum at high energy depending on the detection position and solid angle. Advantage and comparison to other online measurement system, such as the TPS equipped with microchannel plate, are discussed in terms of overlay of ion species, high-repetition rate operation, detection solid angle, and detector characteristics of imaging plate.

Isolation and characterization of mouse mesenchymal stem cells

OBJECTIVE

Mesenchymal stem cells (MSCs) have been studied in regenerative medicine because of their unique immunologic characteristics. However, before clinical application in humans, animal models are needed to confirm their safety and efficacy. To date, appropriate methods and sources to obtain mouse MSCs have not been identified. Therefore, we investigated MSCs isolated from 3 strains of mice and 3 sources for the development of MSCs in a mouse model.

MATERIALS AND METHODS

Male BALB/c, C3H and C57BL/6 mice were used to isolate MSCs from various tissues including bone marrow (BM), compact bone, and adipose tissue. The MSCs were maintained in StemXVivo medium. Immunophenotypes of the MSCs were analyzed by FACS and their growth potential estimated by the number of colony-forming unit fibroblasts.

RESULTS

All MSCs that were isolated from BM, compact bone, and adipose tissue showed plastic-adherent, fibroblastic-like morphologic characteristics regardless of the mouse strain or cell source. However, culture of BM MSCs was less successful than the other tissue types. The FACS phenotype analysis revealed that the MSCs were positive for CD29, CD44, CD105, and Sca-1, but negative for CD34, TER-119, CD45, and CD11b. According to the results of the characterization, the adipose tissue MSCs showed higher growth potential than did other MSCs.

CONCLUSION

The results of this study showed that culture of adipose tissue and compact bone-MSCs was easier than BM MSCs. Based on the results of immunophenotype and growth potential, C57BL/6 AT-MSCs might be a suitable source to establish a mouse model of MSCs.

Poly(vinyl acetate)/clay nanocomposite materials for organic thin film transistor application

Nanocomposite materials of poly(vinyl acetate) (PVAc) and organoclay were fabricated, in order to be utilized as dielectric materials of the organic thin film transistor (OTFT). Spin coating condition of the nanocomposite solution was examined considering shear viscosity of the composite materials dissolved in chloroform. Intercalated structure of the PVAc/clay nanocomposites was characterized using both wide-angle X-ray diffraction and TEM. Fracture morphology of the composite film on silicon wafer was also observed by SEM. Dielectric constant (4.15) of the nanocomposite materials shows that the PVAc/clay nanocomposites are applicable for the gate dielectric materials.

Viral caspase inhibitor p35, but not crmA, is neuroprotective in the ischemic penumbra following experimental stroke

Apoptosis, a predominant cause of neuronal death after stroke, can be executed in a caspase-dependent or apoptosis inducing factor (AIF)-dependent manner. Herpes simplex virus (HSV) vectors expressing caspase inhibitors p35 and crmA have been shown to be neuroprotective against various excitotoxic insults. Here we further evaluated the possible neuroprotective role of p35 and crmA in a rat stroke model. Overexpression of p35, but not crmA, significantly increased neuronal survival. Results of double immunofluorescence staining indicate that compared with neurons infected with crmA or control vectors, p35-infected neurons had less active caspase-3 expression, cytosolic cytochrome c and nuclear AIF translocation.

Comment on “Preparation and electrorheological property of rare earth modified amorphous BaxSr1−xTiO3 gel electrorheological fluid”

The comments on the recent results on electrorheological (ER) property of rare earth modified amorphous barium strontium titanate gel based ER fluid are given via analysis of its dynamic yield stress data as a function of applied electric field strengths. Using our previously reported universal yield stress equation, we obtained the critical electric field strength and collapsed their data onto a single curve.

Phosphorylation of Potato Starch and Its Electrorheological Suspension

Highly substituted potato starch phosphate (HPSP) particles were synthesized via an esterification process of potato starch with a mixture of several different concentrations of disodium hydrogen phosphate and sodium hydrogen phosphate. These particles were characterized via thermogravimetric analysis, scanning electron microscope, and inductively coupled plasma mass spectrometer. The electrorheological (ER) fluid was prepared by dispersing these HPSP particles in nonconducting silicone oil, and their ER properties were investigated. The HPSP particle-based ER fluid exhibited typical ER responses with a nonzero yield stress under an applied electric field. We examined the yield stresses for the potato starch-based anhydrous ER system by varying the degree of phosphate substitution and found that the higher polarization induced by the external electric field strength resulted in the higher values of yield stresses and shear stresses.