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"Shim, C-Y"
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Determinants of exercise-induced pulmonary hypertension in patients with normal left ventricular ejection fraction
Background:Pulmonary hypertension (PH) can occur during exercise and has an adverse effect on functional status, exercise tolerance and prognosis. However, the role of cardiac function abnormalities on exercise-induced PH in patients with normal left ventricular ejection fraction (LVEF) is unclear.Objective:To analyse exercise-induced PH determinants in patients with normal LVEF.Methods and results:396 subjects (160 male, mean age 55 (SD 13)) referred for exercise echocardiography underwent a graded, symptom-limited, supine bicycle exercise with two-dimensional and Doppler echocardiography. Tricuspid regurgitation (TR) velocity was measured at rest and during exercise. Pulmonary artery systolic pressure (PASP) was estimated from TR velocity by adding a right atrial pressure of 10 mm Hg. Patients were classified according to exercise induced PH, defined as present if PASP >50 mm Hg at 50 W of exercise. 135 patients (34%) had PASP >50 mm Hg during exercise. Patients with exercise-induced PH were older, more commonly female and had shorter exercise duration; however, LVEF was significantly higher. The systolic blood pressure at rest and during exercise was significantly higher in patients with exercise-induced PH (rest, 125 (18) vs 132 (18) mm Hg, p = 0.0003; 25 W, 146 (21) vs 157 (21) mm Hg, p<0.0001; 50 W, 157 (24) vs 170 (22) mm Hg, p<0.0001; 75 W, 168 (23) vs 183 (22) mm Hg, p<0.0001). Despite similar resting oxygen saturation, exercise oxygen saturation was significantly lower in subjects with exercise-induced PH than in those without. Numerous echocardiographic variables were significantly different between groups. In multivariate analysis, resting TR velocity (p<0.0001), E/E′ (p = 0.027), age and gender were the strongest predictors of PASP during exercise.Conclusion:Exercise-induced PH is common even in subjects with normal LVEF. It is strongly associated with E/E′ ratio, TR velocity, age, systolic blood pressure during exercise and gender.
Journal Article
Left ventricular diastolic functional reserve during exercise in patients with impaired myocardial relaxation at rest
by
Choi, E-Y
,
Ha, J-W
,
Park, S
in
Biological and medical sciences
,
Blood pressure
,
Cardiology. Vascular system
2009
Background: Patients with similar grade diastolic dysfunction at rest may have a spectrum of alterations in diastolic function during exercise. Objective: To evaluate (a) whether exercise could unmask further diastolic abnormalities not evident during rest; (b) whether diastolic functional reserve during exercise is associated with exercise capacity. Methods: 141 subjects (77 male, mean (SD) age 62 (9)) with abnormal left ventricular (LV) relaxation (mitral E/A <0.75) and/or deceleration time >240 ms, underwent graded supine bicycle exercise with simultaneous respiratory gas analysis and two-dimensional and Doppler echocardiographic study. Mitral inflow and annular velocities were measured at rest and during exercise. The LV diastolic function reserve index (DFRI) was calculated. Results: Patients were classified into two groups: group 1 (n = 64), DFRI <13.5; group 2 (n = 77), DFRI ⩾13.5. The ratio of E/E′ to stroke volume was used as an index of ventricular elastance (Ed). No significant differences between the groups in mitral inflow and annular velocities at rest were found. Mean (SD) Ed was not significantly different at rest between the groups (0.19 (0.07) vs 0.18 (0.06), p = 0.29). Ed was significantly higher during exercise in group 1 than in group 2 (25 W, 0.21 (0.09) vs 0.14 (0.04), p<0.001; 50 W, 0.22 (0.10) vs 0.15 (0.04), p<0.001). Group 1 subjects had a shorter exercise duration (8.2 (2.7) vs 9.4 (3.7) min, p = 0.04) and lower peak oxygen consumption (17.5 (4.5) vs 20.2 (5.4) ml/kg/min, p = 0.005). Conclusions: Despite similar mitral flow and annular velocities at rest, different responses to exercise were seen in patients with abnormal LV relaxation at rest. Lower LV diastolic functional reserve was associated with higher ventricular elastance during exercise, and reduced exercise capacity.
Journal Article
Overweight and Its Association With Aortic Pressure Wave Reflection After Exercise
by
Yang, Woo-In
,
Choi, Donghoon
,
Ko, Young-Guk
in
Aged
,
Aorta - physiology
,
Arterial hypertension. Arterial hypotension
2011
Background
Obesity is associated with arterial stiffening, left ventricular (LV) hypertrophy, and diastolic dysfunction. However, there is no data regarding dynamic changes in arterial hemodynamics with exercise in overweight subjects. We hypothesized that overweight women would show a different exercise response in wave reflection compared with lean women.
Methods
A total of 59 overweight and 68 lean nondiabetic women (mean age 63 ± 7 years) underwent symptom-limited supine bicycle exercise testing with simultaneous two-dimensional and Doppler echocardiography. Central hemodynamics including central aortic pressure and augmentation index (AIx) were obtained at rest and immediately after peak exercise using radial artery tonometry.
Results
Overweight women showed a higher LV mass index (lean vs. overweight; 40.2 ± 10.2 vs. 45.3 ± 11.0g/m2.7, P = 0.007) and a lower early diastolic mitral annular velocity (6.3 ± 1.8 vs. 5.5 ± 1.6 cm/s, P = 0.013) than lean women. Although the two groups did not differ in peripheral and central hemodynamics including AIx (36.3 ± 11.7 vs. 36.8 ± 10.2%, P = 0.830) and AIx normalized for heart rate 75/min (AIx@75, 30.4 ± 11.5 vs. 30.1 ± 9.9%, P = 0.885) at rest, AIx (20.9 ± 11.5 vs. 27.6 ± 10.4%, P = 0.004) and AIx@75 (25.8 ± 10.2 vs. 31.6 ± 7.7%, P = 0.002) at peak exercise were significantly higher in overweight women. In simple correlation analysis, body mass index (BMI) showed significant correlations with AIx, and AIx@75 at peak exercise, whereas no relationships were found with those parameters at rest. Multiple regression analysis showed that BMI was an independent determinant of AIx@75 at peak exercise (β = 0.28, P = 0.004).
Conclusions
Despite similar resting peripheral and central hemodynamics, the wave reflection in overweight women after exercise differed from that in lean women. These findings suggest that being overweight is related to higher wave reflection after exercise.
American Journal of Hypertension advance online publication 11 August 2011; doi:10.1038/ajh.2011.121
Journal Article
Managing Pervasive Computing and Ubiquitous Communications: A Report on APNOMS 2003
2003
The 7th Asia-Pacific Network Operations and Management Symposium (APNOMS 2003) was held during October 1-3, 2003 in Fukuoka, Japan. APNOMS 2003, which was organized by MICE TM (The Institute of Electronics Information and Communication Engineers, Telecommunication Management Committee) and KICS KNOM (The Korean Institute of Communication Science, Korean Network Operations and Management Committee) with support from IEEE CNOM (Committee on Network Operations and Management), IEEE APB (Asia Pacific Board), IEEE ComSoc Japan Chapter and TMF (TeleManagement Forum), has continued to play an important role in exchanging and discussing all aspects of telecommunications management among academics and telecommunication industry at large in the Asia-Pacific region. As in the previous symposia [1-5], APNOMS 2003 was a great success, attracting about 250 researchers, practitioners, operators, and vendors from 10 countries. Its program included keynote speeches, tutorials, special sessions, technical sessions, poster sessions, a distinguished experts panel, and exhibitions.
Journal Article
Numerical Evaluation of Flow and Performance of Turbo Pump Inducers
2004
Steady state flow calculations are executed for turbo-pump inducers of modern design to validate the performance of Tascflow code. Hydrodynamic performance of inducers is evaluated and structure of the passage flow and leading edge recirculation are also investigated. Calculated results show good coincidence with experimental data of static pressure performance and velocity profiles over the leading edge. Upstream recirculation, tip leakage and vortex flow at the blade tip and near leading edge are main sources of pressure loss. Amount of pressure loss from the upstream to the leading edge corresponds to that of whole pressure loss through the blade passage. The viscous loss is considerably large due to the strong secondary flow. There appears more stronger leading edge recirculation for the backswept inducer. and this increases the pressure loss. However, blade loading near the leading edge is considerably reduced and cavitation inception delayed.
Journal Article
Evolution of endemism on a young tropical mountain
2015
Investigating the evolutionary origins of montane biodiversity by sampling the entire biota from a single mountain, Mount Kinabalu in Borneo, allows for a better understanding not only of the origins of endemism, but also of this biota’s forecasted response to environmental change.
Evolution of a mountain biota
Mount Kinabalu in Malaysian Borneo, is the tallest peak between the Himalayas and New Guinea, and like other tropical mountains it is a biodiversity hotspot, containing many endemic species isolated by altitude. These authors investigate the evolutionary origins of such biodiversity by sampling the entire biota from Mount Kinabalu, including frogs, insects, arachnids, snails, leeches, mosses, flowering plants, ferns, and fungi. DNA barcoding reveals that most of the species are younger than the 6-million-year-old mountain, and are either relatives of lowland species that have shifted their niche upwards or long-distance immigrants from other high-altitude areas. Understanding the origins of montane biodiversity will help understand its response to environmental change.
Tropical mountains are hot spots of biodiversity and endemism
1
,
2
,
3
, but the evolutionary origins of their unique biotas are poorly understood
4
. In varying degrees, local and regional extinction, long-distance colonization, and local recruitment may all contribute to the exceptional character of these communities
5
. Also, it is debated whether mountain endemics mostly originate from local lowland taxa, or from lineages that reach the mountain by long-range dispersal from cool localities elsewhere
6
. Here we investigate the evolutionary routes to endemism by sampling an entire tropical mountain biota on the 4,095-metre-high Mount Kinabalu in Sabah, East Malaysia. We discover that most of its unique biodiversity is younger than the mountain itself (6 million years), and comprises a mix of immigrant pre-adapted lineages and descendants from local lowland ancestors, although substantial shifts from lower to higher vegetation zones in this latter group were rare. These insights could improve forecasts of the likelihood of extinction and ‘evolutionary rescue’
7
in montane biodiversity hot spots under climate change scenarios.
Journal Article
Sharing health information online in South Korea: motives, topics, and antecedents
Abstract
This study aimed to examine the motives, topics and antecedents for sharing health information online among Korean Internet users. Eight hundred adults completed a web-based survey exploring the motives; topics; physical, cognitive, affective and environmental factors; and experiences relating to sharing health information online. The motives for not sharing information included information absence and inappropriateness. The most preferred topic was disease. Good subjective health was significantly associated with frequent information sharing while individuals with a history of disease involving themselves or family members were more likely to share health information than were those without such a history. Further, a higher level of depressed mood was related to a higher level of sharing. Internet-related self-efficacy and trust in information delivery channels were positively related to sharing. Future research could extend the factors related to information sharing to include the evaluation of shared information.
Journal Article
Ethanol Extract of Cudrania tricuspidata Leaf Ameliorates Hyperuricemia in Mice via Inhibition of Hepatic and Serum Xanthine Oxidase Activity
2018
Cudrania tricuspidata Bureau (Moraceae) (CT) is a dietary and medicinal plant distributed widely in Northeast Asia. There have been no studies on the effect of CT and/or its active constituents on in vivo xanthine oxidase (XO) activity, hyperuricemia, and gout. The aim of this study was to investigate XO inhibitory and antihyperuricemic effects of the ethanol extract of CT leaf (CTLE) and its active constituents in vitro and in vivo. Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) analyses were used to determine a chemical profile of CTLE. XO inhibitory and antihyperuricemic effects of CTLE given orally (30 and 100 mg/kg per day for 1 week) were examined in potassium oxonate-induced hyperuricemic ICR mice. CTLE exhibited XO inhibitory activity in vitro with an IC50 of 368.2 μg/mL, significantly reduced serum uric acid levels by approximately 2-fold (7.9 nM in normal mice; 3.8 nM in 30 mg/kg CTLE; 3.9 nM in 100 mg/kg CTLE), and significantly alleviated hyperuricemia by reducing hepatic (by 39.1 and 41.8% in 30 and 100 mg/kg, respectively) and serum XO activity (by 30.7 and 50.1% in 30 and 100 mg/kg, respectively) in hyperuricemic mice. Moreover, several XO inhibitory and/or antihyperuricemic phytochemicals, such as stigmasterol, β-sitosterol, vitamin E, rutin, and kaempferol, were identified from CTLE. Compared with rutin, kaempferol showed markedly higher XO inhibitory activity in vitro. Our present results demonstrate that CTLE may offer a promising alternative to allopurinol for the treatment of hyperuricemia and gout.
Journal Article
Clinical Usefulness of Eschar Polymerase Chain Reaction for the Diagnosis of Scrub Typhus: A Prospective Study
2006
Background. The aim of this study was to determine the diagnostic utility of performing eschar polymerase chain reaction (PCR) for the diagnosis of scrub typhus through a prospective comparison of eschar PCR results with indirect immunofluorescent antibody assay (IFA) results. Methods. We conducted a multicenter prospective study involving patients with possible scrub typhus. Whole-blood samples and eschars were obtained for serological evaluation and PCR. A new crust was formed several days later at the site of the removed eschar. The newly formed crust was taken for performance of the second eschar PCR. Additional blood samples and eschars were collected, if possible, at 1-week intervals for 1 month after antibiotic treatment. Results. We prospectively studied 135 patients with possible scrub typhus. Of these patients, 118 had scrub typhus confirmed on the basis of either a single indirect immunofluorescent specific immunoglobulin M titer against Orientia tsutsugamushi of ⩾1 : 10 or a ⩾4-fold increase in the follow-up titer. The results of nested PCR assay of the eschars demonstrated a sensitivity of 0.86 (95% confidence interval, 0.78–0.92) and a specificity of 1 (95% confidence interval, 0.05–1). Among the 50 patients who showed positive results of eschar PCR at admission, 46 (92%) also showed positive results for the follow-up PCR test of the newly formed eschar after the treatment with antibiotics. Conclusions. The eschar PCR assay was useful as a rapid and reliable test to confirm the diagnosis of scrub typhus, even though the patients received treatment with appropriate antibiotics, such as macrolides, quinolones, and tetracycline, which are all active against Orientia and Rickettsia species.
Journal Article
Inhaled indacaterol for the treatment of COPD patients with destroyed lung by tuberculosis and moderate-to-severe airflow limitation: results from the randomized INFINITY study
by
Park, Myung-Jae
,
Shim, Jae Jeong
,
Oh, Yeon-Mok
in
Abbreviations
,
Administration, Inhalation
,
Adrenergic beta-2 Receptor Agonists - administration & dosage
2017
Pulmonary tuberculosis (TB) is a risk factor for chronic obstructive pulmonary disease (COPD); however, few clinical studies have investigated treatment effectiveness in COPD patients with destroyed lung by TB. The Indacaterol effectiveness in COPD patients with Tuberculosis history (INFINITY) study assessed the efficacy and safety of once-daily inhaled indacaterol 150 µg for the treatment of Korean COPD patients with destroyed lung by TB and moderate-to-severe airflow limitation.
This was a multicenter, double-blind, parallel-group study, in which eligible patients were randomized (1:1) to receive either once-daily indacaterol 150 µg or placebo for 8 weeks. The primary efficacy endpoint was change from baseline in trough forced expiratory volume in 1 s at Week 8; the secondary endpoints included changes in transition dyspnea index score and St George's Respiratory Questionnaire for COPD score at Week 8. Safety was evaluated over 8 weeks.
Of the 136 patients randomized, 119 (87.5%) completed the study treatment. At Week 8, indacaterol significantly improved trough forced expiratory volume in 1 s versus placebo (treatment difference [TD] 140 mL,
<0.001). Statistically significant improvement in transition dyspnea index score (TD =0.78,
<0.05) and numerical improvement in St George's Respiratory Questionnaire for COPD score (TD =-2.36,
=0.3563) were observed with indacaterol versus placebo at Week 8. Incidence of adverse events was comparable between the treatment groups.
Indacaterol provided significantly superior bronchodilation, significant improvement in breathlessness and improved health status with comparable safety versus placebo in Korean COPD patients with destroyed lung by TB and moderate-to-severe airflow limitation.
Journal Article