Identification, In Silico Characterization, and Differential Expression Profiles of Carotenoid, Xanthophyll, Apocarotenoid Biosynthetic Pathways Genes, and Analysis of Carotenoid and Xanthophyll Accumulation in Heracleum moellendorffii Hance.

Heracleum moellendorffii Hance is a non-woody forest plant widely used in China, Korea, and Japan because of its various therapeutic properties. However, the genetic details of the carotenoid pathway (CP), xanthophyll pathway (XP), and apocarotenoid pathway (AP) genes have not been studied. Thus, the CP, XP, and AP genes of H. moellendorffii were detected and analyzed. A total of fifteen genes were identified, of which eight, four, and three belonged to CP, XP, and AP, respectively. All identified genes possessed full open reading frames. Phylogenetic characterization of the identified gene sequences showed the highest similarity with other higher plants. Multiple alignments and 3D dimensional structures showed several diverse conserved motifs, such as the carotene-binding motif, dinucleotide-binding motif, and aspartate or glutamate residues. The results of real-time PCR showed that the CP, XP, and AP genes were highly expressed in leaves, followed by the stems and roots. In total, eight different individual carotenoids were identified using HPLC analysis. The highest individual and total carotenoid content were achieved in the leaves, followed by the stems and roots. This study will provide more information on the gene structure of the CP, XP, and AP genes, which may help to increase the accumulation of carotenoids in H. moellendorffii through genetic engineering. These results could be helpful for further molecular and functional studies of CP, XP, and AP genes.

Compression automation of circular stapler for preventing compression injury on gastrointestinal anastomosis.

BACKGROUND: Conventional manual compression relies on the surgeon's subjective sensations, so excessive compression can cause tissue injury to the stapling line of the intestinal anastomosis. METHODS: Automatic compression monitoring and compression control system was developed for circular stapler. The tissue injury related compression variables were evaluated and accommodated by compression control device. The compression injury-reducing performance was verified on collagen sheets of in vitro experiments. RESULTS: Excessive pressure and tissue deformation were associated with compression-induced tissue damages. The safe pressure range was very narrow in weaker tissue than normal collagen. The automatic system performed proper compression within a safe pressure range without tissue injury. CONCLUSIONS: Manual compression of circular stapler could cause tissue injuries by excessive pressure and tissue deformation. Our automatic compression system is designed to control peak pressure to prevent the compressive tissue injury.

Impact of copper treatment on phenylpropanoid biosynthesis in adventitious root culture of Althaea officinalis L.

Althaea officinalis has been widely used in various pharmaceutical applications. The biological effects and significance of phenylpropanoids in numerous industries are well studied. However, fulfilling consumer demand for these commercially important compounds is difficult. The effect of heavy-metal toxic influence on plants is primarily due to a strong and rapid suppression of growth processes, as well as the decline in activity of the photosynthetic apparatus, also associated with progressing senescence processes. Some of the secondary metabolite production was triggered by the application of heavy metals, but there was not a stress response. In the adventitious root culture of A. officinalis, copper-mediated phenylpropanoid biosynthesis has been investigated in both concentration-and duration-dependent manners. High-performance liquid chromatography (HPLC) analysis revealed a total of nine different phenolic compounds in response to different concentrations of copper chloride. In this study, high productivity of phenolic compounds was observed in the copper chloride treated-adventitious root culture of A. officianalis. In particular, a low concentration of copper chloride led to a significant accumulation of phenolic compounds under optimal conditions. Moreover, all genes responsible for phenylpropanoid biosynthesis may be sensitive to phenolic compound production following copper treatment. Especially, the highest change in transcript level was observed from AoANS at 6 h. According to our findings, treatment with copper chloride (0.5 mM) for 48 or 96 h can be an appropriate method to maximize phenylpropanoid levels in A. officinalis adventitious root culture.

Targeted Metabolic and In-Silico Analyses Highlight Distinct Glucosinolates and Phenolics Signatures in Korean Rapeseed Cultivars.

Rapeseed is an economically important oilseed crop throughout the world. We examined the content and composition of glucosinolates (GSLs) and phenolics in the sprouts of seven Korean cultivars. A total of eight GSLs that include four aliphatic GSLs (AGSLs) (progoitrin, gluconapin, gluconapoleiferin, and glucobrassicanapin) and four indole GSLs (IGSLs) (4-methoxyglucobrassicin, 4-hydroxyglucobrassicin, neoglucobrassicin, and glucobrassicin) were identified in these cultivars. Of the total GSLs, the highest level was detected for progoitrin, while the lowest level was identified for glucobrassicanapin in all the cultivars. Phenolics that include chlorogenic acid, catechin hydrate, 4-hydroxybenzoic acid, gallic acid, ferulic acid, p-coumaric acid, epicatechin, caffeic acid, rutin, quercetin, trans-cinnamic acid, benzoic acid, and kaempferol were present in all the cultivars. Of these, rutin was identified with the highest level while trans-cinnamic acid was identified with the lowest level in all the cultivars. Cluster analysis revealed the unique metabolic signature of eight GSLs and thirteen phenolics for the seven cultivars of rapeseed, which implies that genomic commonality and variability resulted from the previous breeding program. Further, gene expression and cis-regulatory elements suggest that the biosynthesis of GSLs and phenolics of these cultivars appears to be regulated through transcription factors associated with stress responses, phytohormones, and cellular growth.

Optimization of indocyanine green angiography for colon perfusion during laparoscopic colorectal surgery.

AIM: This study aims to evaluate the extrinsic effects of conditional factors affecting quantitative parameters and to establish the optimization of indocyanine green (ICG) angiography using in vitro experiments and a prospective observational study. METHOD: In vitro experiments were performed to evaluate the correlation between conditional factors such as camera distance, surrounding lighting, fluorescence emission sources and ICG doses. The fluorescence intensity was measured from the ICG-containing test tube in each condition. In the clinical study, ICG angiography was applied to patients with colorectal cancer (n = 164). The quantitative perfusion parameters were the maximal fluorescence intensity (FMAX ), slope, T1/2MAX and perfusion time ratio (TR). Camera position, distance to colon, fluorescence emission source, surrounding lighting, site of angiography and ICG specific mode were considered as conditional factors and compared with the quantitative parameters to identify the optimal condition of ICG angiography. RESULTS: The fluorescence intensity had an inverse correlation with distance, and the transitional zone was shown at a distance of 4-5 cm by slope differential. FMAX , T1/2MAX and slope were affected significantly by camera distance, site of angiography, fluorescence emission source and ICG mode as conditional factors. On multivariate analysis, FMAX was independently associated with spectral ICG mode with red inversion, laser mode and camera distance. Conversely, TR was not related to any conditional factors. CONCLUSION: Since quantitative parameters of ICG angiography are influenced by various conditions, a standardized protocol is required. The application of ICG specific modes with a constant distance of 4-5 cm can provide optimized fluorescence images.

Elevated Ozone Levels Affect Metabolites and Related Biosynthetic Genes in Tartary Buckwheat.

Global climate change and the industrial revolution have increased the concentration of tropospheric ozone, a photochemical air pollutant that can negatively affect plant growth and crop production. In the present study, we investigated the effects of O3 on the metabolites and transcripts of tartary buckwheat. A total of 36 metabolites were identified by gas chromatography coupled with time-of-flight mass spectrometry, and principal component analysis was performed to verify the metabolic differences between nontreated and O3-treated tartary buckwheat. The content of threonic acid increased after 2 days of the O3 treatment, whereas it decreased after 4 days of exposure, after which it gradually increased until the eighth day of exposure. In addition, the levels of most metabolites decreased significantly after the O3 treatment. On the contrary, the levels of two anthocyanins, cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside, increased more than 11.36- and 11.43-fold, respectively, after the O3 treatment. To assess the effect of O3 on the genomic level, we analyzed the expression of anthocyanin biosynthesis pathway genes in O3-treated and nontreated buckwheat using quantitative real-time reverse transcription polymerase chain reaction (PCR). We found that the expression of all anthocyanin pathway genes increased significantly in the O3-treated buckwheat compared to that in the nontreated buckwheat. Altogether, our results suggested that O3 affected the transcripts and metabolites of tartary buckwheat, which would eventually cause phenotypic changes in plants.

Improvement of viewing angle dependence of bottom-emitting green organic light-emitting diodes with a strong microcavity effect.

The current efficiency and color purity of organic light-emitting diodes (OLEDs) can be easily improved by means of a microcavity structure, but this improvement is typically accompanied by a deterioration in the characteristics of viewing angle. To minimize the angular dependence of the color characteristics exhibited by these strong microcavity devices, we investigated the changes in the optical properties of the green OLED with a bottom resonant structure. This investigation was based on varying the hole transport layer and semitransparent anode thicknesses. The results of optical simulations revealed that the current efficiency and viewing angle characteristics can be simultaneously improved by adjusting the thickness of the two layers. Furthermore, optical simulations predicted that the angular color dependence could be limited to 0.019 in the International Commission on Illumination (CIE) 1976 coordinate system. This optimum condition yielded a current efficiency of ∼134 cd/A. To further reduce this color shift, a nanosized island array (NIA) was introduced through the dewetting process of cesium chloride. By employing NIAs, the color coordinate shift value was reduced to 0.016 in the CIE 1976 coordinate system, and a current efficiency of 130.7 cd/A was achieved.

Blood Pressure Reference Values for Normal Weight Korean Children and Adolescents: Data from The Korea National Health and Nutrition Examination Survey 1998-2016: The Korean Working Group of Pediatric Hypertension.

BACKGROUND AND OBJECTIVES: Hypertension is becoming one of the most common health conditions in children and adolescents due to increasing childhood obesity. We aimed to provide the auscultatory blood pressure (BP) normative reference values for Korean non-overweight children and adolescents. METHODS: BP measurements in children and adolescents aged 10 to 18 years were performed in the Korean National Health and Nutrition Examination Survey (KNHANES) from 1998 to 2016. BP was measured using a mercury sphygmomanometer. Sex-, age- and height-specific systolic BP (SBP) and diastolic BP (DBP) percentiles were calculated in the non-overweight children (n=10,442). We used the General Additive Model for Location Scale and Shape method to calculate BP percentiles. RESULTS: The 50th, 90th, 95th, and 99th percentiles of SBP and DBP tables and graphs of non-overweight children and adolescents aged 10 to 18 years were presented by age and height percentiles. We found that the SBP and DBP at the 95th percentile were well correlated with height. The BP tables presented by height contained BP values from 124 cm to 190 cm for boys and from 120 cm to 178 cm for girls. Boys had higher SBP and DBP. CONCLUSIONS: We provided the sex-, age- and height-specific auscultatory BP values using the KNHANES big data. These may be useful in diagnosis and treatment of hypertension in Korean children and adolescents.

Comparative analysis of glucosinolate production in hairy roots of green and red kale (Brassica oleracea var. acephala).

Glucosinolates (GSLs) are sulfur- and nitrogen-containing secondary metabolites that function in plant defense and provide benefits to human health. In this study, using Agrobacterium rhizogenes R1000, green and red kale hairy roots were established. The expression levels of GSLs biosynthesis genes and their accumulation in both kale hairy roots were analyzed by quantitative real-time PCR and HPLC. The results showed that the expression of most indolic GSLs biosynthesis genes was higher in the hairy roots of green kale than in that of red kale. In contrast, the expression of BoCYP83A1 and BoSUR1 encoding key enzymes aromatic GSL biosynthesis was significantly higher in red kale hairy root. The HPLC analysis identified six GSLs. The levels of 4-methoxyglucobrassicin, glucobrassicin, and 4-hydroxyglucobrassicin were 6.21, 5.98, and 2 times higher, respectively, in green kale than in red kale, whereas the levels of neoglucobrassicin and gluconasturtiin were 16.2 and 3.48 times higher, respectively, in red kale than in green kale. Our study provides insights into the underlying mechanisms of GSLs biosynthesis in kale hairy roots and can be potentially used as "biological factories" for producing bioactive substances such as GSLs.

Enhancement of Glucosinolate Production in Watercress ( Nasturtium officinale) Hairy Roots by Overexpressing Cabbage Transcription Factors.

Glucosinolates are secondary metabolites that play important roles in plant defense and human health, as their production in plants is enhanced by overexpressing transcription factors. Here, four cabbage transcription factors (IQD1-1, IQD1-2, MYB29-1, and MYB29-2) affecting genes in both aliphatic and indolic glucosinolates biosynthetic pathways and increasing glucosinolates accumulation were overexpressed in watercress. Five IQD1-1, six IQD1-2, five MYB29-1, six MYB29-2, and one GUS hairy root lines were created. The expression of all genes involved in glucosinolates biosynthesis was higher in transgenic lines than in the GUS hairy root line, in agreement with total glucosinolates contents, determined by high-performance liquid chromatography. In transgenic IQD1-1 (1), IQD1-2 (4), MYB29-1 (2), and MYB29-2 (1) hairy root lines, total glucosinolates were 3.39-, 3.04-, 2.58-, and 4.69-fold higher than those in the GUS hairy root lines, respectively. These results suggest a central regulatory function for IQD1-1, IQD1-2, MYB29-1, and MYB29-2 transcription factors in glucosinolates biosynthesis in watercress hairy roots.

Effects of Light-Emitting Diodes on the Accumulation of Glucosinolates and Phenolic Compounds in Sprouting Canola (Brassica napus L.).

In this study, we investigated optimal light conditions for enhancement of the growth and accumulation of glucosinolates and phenolics in the sprouts of canola (Brassica napus L.). We found that the shoot lengths and fresh weights of red light-irradiated sprouts were higher than those of sprouts exposed to white, blue, and blue + red light, whereas root length was not notably different among red, blue, white, and blue + red light treatments. The accumulations of total glucosinolates in plants irradiated with white, blue, and red lights were not significantly different (19.32 ± 0.13, 20.69 ± 0.05, and 20.65 ± 1.70 mg/g dry weight (wt.), respectively). However, sprouts exposed to blue + red light contained the lowest levels of total glucosinolates (17.08 ± 0.28 mg/g dry wt.). The accumulation of total phenolic compounds was the highest in plants irradiated with blue light (3.81 ± 0.08 mg/g dry wt.), 1.33 times higher than the lowest level in plants irradiated with red light (2.87 ± 0.05 mg/g dry wt.). These results demonstrate that red light-emitting diode (LED) light is suitable for sprout growth and that blue LED light is effective in increasing the accumulation of glucosinolates and phenolics in B. napus sprouts.

Sudden unexpected cardio-respiratory arrest after venipuncture in children.

PURPOSE: This study aimed to investigate the clinical and socioenvironmental characteristics of sudden cardiorespiratory arrest after venipuncture in children. METHODS: We conducted a retrospective email-based survey of all members of the Korean Pediatric Society. The questionnaire included items on patient demographics, socioenvironmental circumstances of the venipuncture, type of cardiorespiratory arrest, symptoms and signs, treatment, prognosis, and presumed cause of the arrest. RESULTS: Fourteen patients were identified. Of these, 13 were young children (<2 years old), and 1 was 14 years old. All patients had been previously healthy and had no specific risk factors for sudden cardiorespiratory arrest. Most cases (n=11, 79%) were defined as cardiac or cardiorespiratory arrest, while the remaining cases (n=3, 21%) were defined as respiratory arrest. Aspiration (n=3), acute myocarditis (n=2), and laryngeal chemoreflex (n=1) were presumed as the causes; however, the exact causes were unclear. The overall prognosis was poor (death, n=7; morbidity, n=5; full recovery, n=2). The medical institutions faced severe backlash because of these incidents (out-of-court settlement, n=5; medical lawsuit, n=5; continuous harassment, n=3). CONCLUSION: Cardiorespiratory arrest after venipuncture is unpredictable and the probable cause of most cases is a vasovagal reaction. Medical personnel must be aware of the risk of unexpected cardiorespiratory arrest during routine intravenous procedures.

Metabolomic Profiling of the White, Violet, and Red Flowers of Rhododendron schlippenbachii Maxim.

Rhododendron schlippenbachii Maxim. is a garden plant that is also used for natural medicines as a consequence of the biological activities of its diverse metabolites. We accordingly profiled two anthocyanins and 40 primary and secondary metabolites in the three different colored flowers. The major anthocyanins found in the flowers were cyanidins. The red flowers exhibited the highest accumulation of anthocyanins (1.02 ± 0.02 mg/g dry weight). Principal component analysis was applied to the GC‒TOFMS data. The levels of key tricarboxylic acid cycle intermediates in red flowers, such as succinic acid, fumaric acid, and malic acid, were found to be highly significantly different (p < 0.0001) from those in the flowers of other colors. In this study, we aimed to determine metabolite interactions and phenotypic variation among white, violet, and red flowers of R. schlippenbachii by using gas chromatography time-of-flight mass spectrometry (GC‒TOFMS) and high-performance liquid chromatography (HPLC).

Light modulation of top emission organic light emitting diodes showing strong microcavity effect by applying multilayered scattering film.

In order to suppress the viewing angle dependence of top emission organic light emitting diodes (TEOEDs) on a strong microcavity structure, we prepared multi-layered nano scattering film which was consisted with transparent planarizing layer and hazy crosslinked scattering layer. Through such an approach, we could obtain not only a stable color shift and luminance distribution with viewing angle but also a negligible pixel blur level. Meanwhile, we investigated a black tint level of TEOLEDs after attachment of circular polarizer (CP) on various nano scattering films because nano scattering film deteriorates a black level. We found that the black level could be improved from the black tint by reducing the refractive index difference between planarizing layer and scattering layer.

Association of Toll-like receptor 2-positive monocytes with coronary artery lesions and treatment nonresponse in Kawasaki disease.

PURPOSE: Activation of Toll-like receptor 2 (TLR2) present on circulating monocytes in patients with Kawasaki disease (KD) can lead to the production of proinflammatory cytokines and interleukin-10 (IL-10). We aimed to determine the association of the frequency of circulating TLR2+/CD14+ monocytes (FTLR2%) with the outcomes of KD, as well as to compare FTLR2% to the usefulness of sIL-10. METHODS: The FTLR2% in patients with KD was measured by flow cytometry. Serum levels of IL-10 (sIL-10) were determined in 31 patients with KD before the initial treatment with intravenous immunoglobulin (IVIG) and in 21 febrile controls by using enzyme-linked immunosorbent assay. Patients were classified as having coronary artery lesions (CALs) based on the maximal internal diameters of the proximal right coronary artery and proximal left anterior descending coronary artery one month after the initial diagnosis. RESULTS: We found that FTLR2% greater than 92.62% predicted CALs with 80% sensitivity and 68.4% specificity, whereas FTLR2% more than 94.61% predicted IVIG resistance with 66.7% sensitivity and 71.4% specificity. Moreover, sIL-10 more than 15.52 pg/mL predicted CALs and IVIG resistance with 40% and 66.7% sensitivity, respectively, and 73.7% and 76.2% specificity, respectively. CONCLUSION: We showed that measuring FTLR2% before the initial treatment could be useful in predicting CAL development with better sensitivity than sIL-10 and with results comparable to sIL-10 results for the prediction of IVIG resistance in patients with KD. However, further studies are necessary to validate FTLR2% as a marker of prognosis and severity of KD.

Neonatal diffusion tensor brain imaging predicts later motor outcome in preterm neonates with white matter abnormalities.

BACKGROUND: White matter (WM) abnormalities associated with prematurity are one of the most important causes of neurological disability that involves spastic motor deficits in preterm newborns. This study aimed to evaluate regional microstructural changes in diffusion tensor imaging (DTI) associated with WM abnormalities. METHODS: We prospectively studied extremely low birth weight (ELBW; <1000 g) preterm infants who were admitted to the Neonatal Intensive Care Unit of Hanyang University Hospital between February 2011 and February 2014. WM abnormalities were assessed with conventional magnetic resonance (MR) imaging and DTI near term-equivalent age before discharge. Region-of-interests (ROIs) measurements were performed to examine the regional distribution of fractional anisotropy (FA) values. RESULTS: Thirty-two out of 72 ELBW infants underwent conventional MR imaging and DTI at term-equivalent age. Ten of these infants developed WM abnormalities associated with prematurity. Five of ten of those with WM abnormalities developed cerebral palsy (CP). DTI in the WM abnormalities with CP showed a significant reduction of mean FA in the genu of the corpus callosum (p = 0.022), the ipsilateral posterior limb of the internal capsule (p = 0.019), and the ipsilateral centrum semiovale (p = 0.012) compared to normal WM and WM abnormalities without CP. In infants having WM abnormalities with CP, early FA values in neonatal DTI revealed abnormalities of the WM regions prior to the manifestation of hemiparesis. CONCLUSIONS: DTI performed at term equivalent age shows different FA values in WM regions among infants with or without WM abnormalities associated with prematurity and/or CP. Low FA values of ROIs in DTI are related with later development of spastic CP in preterm infants with WM abnormalities.

The Importance of Esophageal and Gastric Diseases as Causes of Chest Pain.

PURPOSE: Pediatric chest pain is considered to be idiopathic or caused by benign diseases. This study was to find out how much upper gastrointestinal (UGI) diseases are major causes of chest pain in pediatric patients. METHODS: The records of 75 children (42 boys and 33 girls, aged 3-17 years old) who have presented with mainly chest pain from January 1995 to March 2015 were retrospectively reviewed. Chest X-ray and electrocardiography (ECG) were performed in all aptients. Further cardiologic and gastrointestinal (GI) evaluations were performed in indicated patients. RESULTS: Chest pain was most common in the children of 6 and 9 to 14 years old. Esopha-gogastric diseases were unexpectedly the most common direct causes of the chest pain, the next are idiopathic, cardiac diseases, chest trauma, respiratory disease, and psychosomatic disease. Even though 21 showed abnormal ECG findings and 7 showed abnormalities on echocardiography, cardiac diseases were determined to be the direct causes only in 9. UGI endoscopy was performed in 57 cases, and esophago-gastric diseases which thereafter were thought to be causative diseases were 48 cases. The mean age of the children with esophago-gastric diseases were different with marginal significance from that of the other children with chest pain not related with esophago-gastric diseases. All the 48 children diagnosed with treated with GI medicines based on the diagnosis, and 37 cases (77.1%) subsequently showed clinical improvement. CONCLUSION: Diagnostic approaches to find out esophageal and gastric diseases in children with chest pain are important as well as cardiac and respiratory investigations.

Sex differences in the relation of body composition to cardiovascular parameters and functions in Korean adolescents: a school-based study.

OBJECTIVE: Obesity in adolescence is associated with increased cardiovascular risk. The patterns of obesity and body composition differ between boys and girls. It is uncertain how body composition correlates with the cardiovascular system and whether such correlations differ by sex in adolescents. METHODS: Body composition (fat-free mass (FFM), adipose mass, waist circumference (WC)) and cardiovascular parameters and functions were studied in 676 healthy Korean adolescents aged 12-16 years. Partial correlation and path analyses were done. RESULTS: WC correlated with stroke volume (SV) and cardiac output (CO), systolic blood pressure (SBP) and pulse pressure (PP), cardiac diastolic function (ratio of early to late filling velocity (E/A ratio)), and vascular function (pulse wave velocity (PWV)) in boys. Adipose mass was related to SV, CO, SBP, PP, left ventricular mass (LVM), and PWV in girls - and to E/A ratio in both sexes. FFM affected SV, CO, SBP, and PP in both sexes and LVM in boys. Cardiac systolic functions had no relation with any body composition variable in either sex. CONCLUSION: In adolescence, the interdependence of the cardiovascular system and the body composition differs between sexes. Understanding of those relations is required to control adolescent obesity and prevent adult cardiovascular disease.

The role of the pediatrician in youth violence prevention.

School bullying has become a major social problem in Korea after the emergence of media reports on children who committed suicide after being victimized by bullies. In this article, we review the characteristics of bullying, and investigate the role of the pediatrician in the prevention of and intervention against bullying and school violence. Bullying can take on many forms such as physical threat, verbal humiliation, malicious rumors, and social ostracism. The prevalence of bullying in various countries is approximately 10% to 20%. In Korea, the prevalence of school violence is similar but seems to be more intense because of the highly competitive environment. From our review of literature, we found that children who were bullied had a significantly higher risk of developing psychosomatic and psychosocial problems such as headache, abdominal pain, anxiety, and depression than those who were not bullied. Hence, it is important for health practitioners to detect these signs in a child who was bullied by questioning and examining the child, and to determine whether bullying plays a contributing role when a child exhibits such signs. Pediatricians can play an important role in the prevention of or intervention against school violence along with school authorities, parents, and community leaders. Moreover, guidelines to prevent school violence, such as the Olweus Bullying Prevention Program, KiVa of the Finish Ministry of Education, and Connected Kids: Safe, Strong, Secure of the American Academy Pediatrics, should be implemented.

The relationships of body mass index, waist-to-height ratio, and body fat percentage with blood pressure and its hemodynamic determinants in Korean adolescents: a school-based study.

PURPOSE: Obesity is an important risk factor for hypertension in adolescents. We investigated the relationship of obesity-related indices (body mass index [BMI], waist-to-height ratio [WHR], and body fat percentage [%BF]) with blood pressure and the hemodynamic determinants of blood pressure in Korean adolescents. METHODS: In 2008, 565 adolescents, aged 12-16 years, were examined. The %BF of the participants was measured by bioelectrical impedance analysis. Echocardiography and brachial artery pulse tracing were used to estimate the stroke volume (SV), cardiac output (CO), total vascular resistance (TVR), and total arterial compliance (TAC). RESULTS: We noted that BMI, WHR, and %BF were positively correlated with systolic blood pressure (SBP) and diastolic blood pressure (DBP). The positive correlation between BMI and blood pressure (SBP and DBP) persisted after adjustment for WHR and %BF. However, after adjustment for BMI, the positive associations between blood pressure (SBP and DBP) and WHR as well as %BF, were not noted. With regard to the hemodynamic factors, BMI, but not WHR and %BF, was an independent positive factor correlated with SV and CO. TVR had an independent negative association with BMI; however, it was not associated with WHR or %BF. Moreover, we noted that BMI, WHR, and %BF did not affect TAC. CONCLUSION: In Korean adolescents, BMI had an independent positive correlation with SBP and DBP, possibly because of its effects on SV, CO, and TVR. WHR and %BF are believed to indirectly affect SBP and DBP through changes in BMI.