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Chung-Yu Chen,1 Jing Dai,2 I-Fan Chen,3 Kuei-Ming Chou,4 Chen-Kang Chang,5 1Department of Physical Education, 2Department of Sport Performance, National Taiwan University of Sport, Taichung, Taiwan; 3Graduate Institute of Sport Coaching Science, Chinese Culture University, Taipei, Taiwan; 4Department of Combat Sport, 5Sport Science Research Center, National Taiwan University of Sport, Taichung, Taiwan Abstract: The dual-task methodology, conducting two tasks simultaneously, may provide better validity than the traditional single-task tests in the environment that is closely related to real sport competitions. The purpose of this study is to determine the reliability and validity of a dual-task test that aims to measure the reaction time and skill proficiency in roundhouse kicks in elite and sub-elite taekwondo athletes. The dual-task results were compared to those in the single-task movements with various levels of complexity. The single-task movements A, B, and C were composed of one, three, and five roundhouse kicks, respectively. The dual-task movement D was composed of movement C and a push of a button in response to a light stimulus as the secondary task. The subjects were 12 elite and 12 sub-elite male taekwondo athletes. The test included four movements with five repeats of each movement in a randomized order. Each subject conducted the same test on two consecutive days. The intraclass correlation coefficient (ICC) showed moderate-to-high correlation in the premotor time (ICC =0.439–0.634 in elite and ICC =0.681–0.824 in sub-elite), motor time (ICC =0.861–0.956 in elite and ICC =0.721–0.931 in sub-elite), and reaction time (ICC =0.692 in elite and ICC =0.676 in sub-elite) in the secondary task in both groups. The elite athletes had significantly faster premotor time than their sub-elite counterparts in all the four movements (all P

OBJECTIVE: The aim of this study was to investigate the cumulative effects of prolonged, intensive training and rapid weight loss on immunological parameters and antioxidation activity of elite male Taiwanese taekwondo athletes. DESIGN: 16 Elite male taekwondo athletes (mean age, 21.6 (1.3) years; mean height, 173.7 (5.5) cm) volunteered to participate in this study. Beginning at 30 days before a national competition, saliva samples were obtained during a 7-week training, the competition and the postcompetition period. Levels of salivary IgA, cortisol, lactoferrin and free-radical scavenging activity were measured at 30-, 14-, 7- and 1-day precompetition and 1-, 7- and 19-day postcompetition. Body weight and body fat were also recorded. RESULTS: The mean body weight was notably decreased during the week immediately before the competition. Results reveal that the levels of salivary IgA were differentially regulated during the training, competition and recovery period, while the salivary cortisol and lactoferrin concentrations and free-radical scavenging activity were not appreciably affected during the training and the competition period. Furthermore, the results of an upper respiratory tract infection incidence indicate that following the decreases of mucosal immunity, the risk of acquiring infection was significantly increased. CONCLUSIONS: Our results demonstrated that mucosal immunity in elite male taekwondo athletes is modulated by exercise and rapid weight reduction during the training, competition and recovery period. Cumulative effects of prolonged intensive training and rapid weight reduction suppressed mucosal immunity. Furthermore, because of the 'open window' of impaired immunity during the precompetition period, the incidence of upper respiratory tract infection was significantly increased after the competition. [ABSTRACT FROM AUTHOR]

Purpose: Successful participation in taekwondo (TKD) requires athletes to possess quick decision-making abilities and demonstrate technical proficiency during competition. Dehydration, occurring during both training and competition, is widely recognized to have various negative effects., Methods: This study investigated the impact of different levels of dehydration on cognitive function, as measured by the Vienna Test System, and the specific performance of kicking techniques among TKD athletes. Using a randomized crossover design, 12 participants were involved in the study. Before and after 1 hour of training at 80% of maximal heart rate, participants were weighed and provided urine samples. All participants were randomly assigned to 3 different hydration conditions: the euhydrated (EUH) group had unrestricted access to fluid consumption, while the hypohydrated (HYP) and severely HYP (S-HYP) groups experienced reductions of 2.0% and 4.0% of their initial body weight, respectively., Results: The EUH group exhibited better reaction speed in reaction-time test-form S1 than the HYP and S-HYP groups. Notably, the EUH group demonstrated a significantly higher success rate in the front-side kick (EUH 98%, HYP 90%, S-HYP 88%; P < .05). However, the success rates of back roundhouse kick and free head kick were similar among the 3 statuses. Furthermore, postexercise heart rates were found to be significantly higher in the HYP and S-HYP groups compared with the EUH group., Conclusions: This study provides insight into the negative effects of dehydration on cognitive function and TKD-specific performance. It is recommended that TKD athletes maintain optimal hydration levels during training and competition to ensure optimal performance.

An increased risk of cardiovascular events was identified in patients with peripheral artery disease (PAD). Clopidogrel is one of the most widely used antiplatelet medications. However, there are heterogeneous outcomes when clopidogrel is used to prevent cardiovascular events in PAD patients. Here, we use an artificial intelligence (AI)-assisted methodology to identify genetic factors potentially involved in the clopidogrel-resistant mechanism, which is currently unclear. Several discoveries can be pinpointed. Firstly, a high proportion (>50%) of clopidogrel resistance was found among diabetic PAD patients in Taiwan. Interestingly, our result suggests that platelet function test-guided antiplatelet therapy appears to reduce the post-interventional occurrence of major adverse cerebrovascular and cardiac events in diabetic PAD patients. Secondly, AI-assisted genome-wide association study of a single-nucleotide polymorphism (SNP) database identified a SNP signature composed of 20 SNPs, which are mapped into 9 protein-coding genes (SLC37A2, IQSEC1, WASHC3, PSD3, BTBD7, GLIS3, PRDM11, LRBA1, and CNR1). Finally, analysis of the protein connectivity map revealed that LRBA, GLIS3, BTBD7, IQSEC1, and PSD3 appear to form a protein interaction network. Intriguingly, the genetic factors seem to pinpoint a pathway related to endocytosis and recycling of P2Y12 receptor, which is the drug target of clopidogrel. Our findings reveal that a combination of AI-assisted discovery of SNP signatures and clinical parameters has the potential to develop an ethnic-specific precision medicine for antiplatelet therapy in diabetic PAD patients.

Carbohydrate mouth rinsing (CMR) potentially affects the interval training performance of taekwondo athletes. This study explored the effect of CMR on vertical jump, kicking speed, and fatigue index before and after simulated taekwondo competition. In a crossover experimental design, 13 trained taekwondo athletes were randomly divided into the CMR and control trials. After warming up, the participants used 6.6% maltodextrin (CMR trial) or mineral water (control trial) to rinse their mouth. Next, the participants underwent tests of vertical jump, kicking speed, and maximum number of kicks. After the tests, the participants rinsed their mouth again, followed by using Wingate testing bikes for 5-s sprint and 25-s rest to simulate taekwondo competitions. Four repetitions were performed in each round for 2 min for a total of three rounds. The results revealed that the fatigue index of the participants in the CMR trial before and after the simulated competition was significantly lower than that of the control trial. However, the two trials differed nonsignificantly in their performance in vertical jump, kicking speed, and the simulated competition. Overall, the study results indicated that CMR reduces the fatigue index but no change was observed in performance for vertical jump, kicking speed, and the simulated competition of trained taekwondo athletes., Competing Interests: None

Background: Previous studies have illustrated clinical associations between diabetic peripheral neuropathy (DPN) and diabetic kidney disease (DKD). Quantitative sensory testing (QST) can accurately detect thermal perception abnormalities and aid in the early diagnosis of asymptomatic small-fiber DPN in patients with type 2 diabetes. The aim of this study was to determine the predictive value of thermal perception abnormalities by QST to detect DKD., Methods: We prospectively enrolled 432 patients with type 2 diabetes (50.2% male, mean age 57.2 years, and average duration of diabetes 9.9 years) at our hospital between 2016 and 2017. Demographic and clinical data of the patients were recorded and analyzed. Diagnosis and staging of DKD were determined by urinary albumin excretion rate and estimated glomerular filtration rate. The presence of thermal perception abnormalities was determined by QST. Multiple logistic regression and receiver operating characteristic (ROC) analyses were performed to investigate the relationships between thermal perception abnormalities and DKD in these patients., Results: In multiple regression analysis, abnormal cold perception in the lower limbs was associated with an increased risk of advanced DKD. Area under the ROC curve analysis revealed that four-limb cold perception abnormalities had the best discriminatory power (0.741 ± 0.053) to predict advanced DKD., Conclusions: Our results demonstrate the value of using thermal perception abnormalities to identify patients with type 2 diabetes also at risk of DKD., (© 2020 The Author(s). Published by S. Karger AG, Basel.)

Background and Aims: Type 2 diabetes is a global health problem that is associated with a wide variety of vascular complications and associated morbidity and mortality. Klotho is an enzyme and transmembrane protein, and increasing evidence suggests that Klotho may contribute to reduced oxidative stress, improved endothelial function, and vasoprotection. To date, the physiological role of Klotho in vascular complications associated with diabetes is unclear., Methods: We prospectively recruited 252 patients with type 2 diabetes, who visited an outpatient clinic at our hospital between 2009 and 2011. Patients in the top and bottom tertiles of circulating Klotho levels were enrolled for analysis., Results: Of the 168 patients enrolled, 45.8% were male, the mean age was 57.2 years, and the average duration of diabetes was 7.58 years. In multiple regression analysis, a high Klotho level was associated with a reduced risk of developing coronary artery disease and cerebrovascular accidents. Klotho level was also an independent predictor for the development of macroangiopathies within the 7-year study period., Conclusions: Our results suggest that circulating Klotho level is a predictor of long-term macrovascular outcomes in patients with type 2 diabetes., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

The uncoupling protein (UCP) belongs to a family of energy-dissipating proteins in mitochondria. Increasing evidences have indicated that UCPs have immense impact on glucose homeostasis and are key proteins in metabolic syndrome. For applying the findings to clinical practice, we designed a study to explore the association between serum UCPs 1-3 and insulin resistance. This investigation prospectively recorded demographical parameter and collected blood samples of 1071 participants from 4 districts in Northeastern Taiwan during the period from August 2013 to July 2014. Propensity score matching by age and sex in patients with top and bottom third homeostasis model assessment of insulin resistance (HOMA-IR) levels was performed, and 326 subjects were enrolled for further studies. The mean age of the patients was 59.4 years and the majority of them (65.5%) were females. The prevalence of metabolic syndrome was 35.5%. Our results demonstrated that serum UCPs 1-3 were significantly associated with differences in HOMA-IR levels. Multiple logistic regression analysis indicated that low UCP 1 and features of metabolic syndrome, namely hypertension, diabetes, body mass index, and high-density lipoprotein, were independent determinants for high HOMA-IR levels. We thus determined that low serum UCP 1 is a predictor for high resistance to insulin.

The specific demands of a combat-sport discipline may be reflected in the perceptual-motor performance of its athletes. Taekwondo, which emphasizes kicking, might require faster perceptual processing to compensate for longer latencies to initiate lower-limb movements and to give rapid visual feedback for dynamic postural control, while Karate, which emphasizes both striking with the hands and kicking, might require exceptional eye-hand coordination and fast perceptual processing. In samples of 38 Taekwondo athletes (16 females, 22 males; mean age = 19.9 years, SD = 1.2), 24 Karate athletes (9 females, 15 males; mean age = 18.9 years, SD = 0.9), and 35 Nonathletes (20 females, 15 males; mean age = 20.6 years, SD = 1.5), we measured eye-hand coordination with the Finger-Nose-Finger task, and both perceptual-processing speed and attentional control with the Covert Orienting of Visual Attention (COVAT) task. Eye-hand coordination was significantly better for Karate athletes than for Taekwondo athletes and Nonathletes, but reaction times for the upper extremities in the COVAT task-indicative of perceptual-processing speed-were faster for Taekwondo athletes than for Karate athletes and Nonathletes. In addition, we found no significant difference among groups in attentional control, as indexed by the reaction-time cost of an invalid cue in the COVAT task. The results suggest that athletes in different combat sports exhibit distinct profiles of perceptual-motor performance.

Background: The decline in cognitive performance has been shown after fatiguing exercise. Branched-chain amino acids (BCAA) have been suggested to alleviate exercise-induced central fatigue. Arginine and citrulline could remove the excess NH3 accumulation accompanied with BCAA supplementation by increasing nitric oxide biosynthesis and/or urea cycle. The purpose of this study is to investigate the effect of the combined supplementation of BCAA, arginine, and citrulline on central fatigue after three simulated matches in well-trained taekwondo athletes., Methods: In a double-blind randomized cross-over design, 12 male taekwondo athletes performed two trials containing three simulated matches each. Each match contained three 2-min rounds of high-intensity intermittent exercise. At the end of the second match, two different supplementations were consumed. In the AA trial, the subjects ingested 0.17 g/kg BCAA, 0.05 g/kg arginine and 0.05 g/kg citrulline, while placebo was consumed in the PL trial. A validated taekwondo-specific reaction test battery was used to measure the cognitive performance after each match., Results: The premotor reaction time in the three single-task tests and the reaction time in the secondary task in the dual-task test were maintained in the AA trial after three matches, while they were impaired in the PL trial, resulting in significantly better performance in the AA trial. These improvements in the AA trial coincided with significantly lower plasma free tryptophan/BCAA ratio, increased NOx concentrations, and similar NH3 concentrations., Conclusions: This study suggested that the combined supplementation could alleviate the exercise-induced central fatigue in elite athletes.

Cancer and neurodegeneration represent the extreme responses of growing and terminally differentiated cells to cellular and genomic damage. The damage recognition mechanisms of nucleotide excision repair, epitomized by xeroderma pigmentosum (XP), and Cockayne syndrome (CS), lie at these extremes. Patients with mutations in the DDB2 and XPC damage recognition steps of global genome repair exhibit almost exclusively actinic skin cancer. Patients with mutations in the RNA pol II cofactors CSA and CSB, that regulate transcription coupled repair, exhibit developmental and neurological symptoms, but not cancer. The absence of skin cancer despite increased photosensitivity in CS implies that the DNA repair deficiency is not associated with increased ultraviolet (UV)-induced mutagenesis, unlike DNA repair deficiency in XP that leads to high levels of UV-induced mutagenesis. One attempt to explain the pathology of CS is to attribute genomic damage to endogenously generated reactive oxygen species (ROS). We show that inhibition of complex I of the mitochondria generates increased ROS, above an already elevated level in CSB cells, but without nuclear DNA damage. CSB, but not CSA, quenches ROS liberated from complex I by rotenone. Extracellular signaling by N-methyl-D-aspartic acid in neurons, however, generates ROS enzymatically through oxidase that does lead to oxidative damage to nuclear DNA. The pathology of CS may therefore be caused by impaired oxidative phosphorylation or nuclear damage from neurotransmitters, but without damage-specific mutagenesis. Environ. Mol. Mutagen. 57:322-330, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Background/purpose: The most common diagnostic finding of autoimmune thyroid disease (AITD) is the presence of antithyroid antibodies. While autoimmune thyroiditis (AT) is a common AITD, aspiration cytology is one of the important diagnostic tools of AT., Methods: We evaluated 116 AT patients with ultrasound-guided aspiration cytology and then analyzed the correlation between thyroid hormone status and thyroid autoantibodies. This was a retrospective analysis with prospective collection of data with a mean follow-up period of 68.8 ± 37.8 months. The patients were classified as either euthyroid, hypothyroid, or hyperthyroid (HT). Of the 116 patients, 22 were hypothyroid, 37 were euthyroid, and 57 were HT., Results: During the follow-up period, 95.5% of the hypothyroid group remained hypothyroid and only one patient improved to euthyroid. In the euthyroid group, 16.2% progressed to hypothyroid and 83.8% remained euthyroid. In the HT group, 8.7% progressed to hypothyroid, 70.2% progressed to euthyroid, and 21.1% remained HT. Most patients with a high titer of thyroglobulin antibody (TgAb) will progress to hypothyroid, and patients with a high titer of thyroid stimulating hormone (TSH) receptor antibody (TRAb) will remain HT. Strong correlations between thyroid functional status and positive number of thyroid autoantibodies were seen in this study. Patients with all the three antibodies positive had a high prevalence of hyperthyroidism., Conclusion: In our study, most patients were HT; this may be because of the early diagnosis and treatment of AT in our clinic. Although antithyroperoxidase antibody (TPOAb) is a hallmark antibody of HT, it cannot predict the initial presentation and clinical outcome., (Copyright © 2013. Published by Elsevier B.V.)

Obesity and the metabolic syndrome have evolved to be major health issues throughout the world. Whether loss of genome integrity contributes to this epidemic is an open question. DNA polymerase η (pol η), encoded by the xeroderma pigmentosum (XP-V) gene, plays an essential role in preventing cutaneous cancer caused by UV radiation-induced DNA damage. Herein, we demonstrate that pol η deficiency in mice (pol η(-/-)) causes obesity with visceral fat accumulation, hepatic steatosis, hyperleptinemia, hyperinsulinemia, and glucose intolerance. In comparison to WT mice, adipose tissue from pol η(-/-) mice exhibits increased DNA damage and a greater DNA damage response, indicated by up-regulation and/or phosphorylation of ataxia telangiectasia mutated (ATM), phosphorylated H2AX (γH2AX), and poly[ADP-ribose] polymerase 1 (PARP-1). Concomitantly, increased cellular senescence in the adipose tissue from pol η(-/-) mice was observed and measured by up-regulation of senescence markers, including p53, p16(Ink4a), p21, senescence-associated (SA) β-gal activity, and SA secretion of proinflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) as early as 4 wk of age. Treatment of pol η(-/-) mice with a p53 inhibitor, pifithrin-α, reduced adipocyte senescence and attenuated the metabolic abnormalities. Furthermore, elevation of adipocyte DNA damage with a high-fat diet or sodium arsenite exacerbated adipocyte senescence and metabolic abnormalities in pol η(-/-) mice. In contrast, reduction of adipose DNA damage with N-acetylcysteine or metformin ameliorated cellular senescence and metabolic abnormalities. These studies indicate that elevated DNA damage is a root cause of adipocyte senescence, which plays a determining role in the development of obesity and insulin resistance.

Cockayne syndrome (CS) is a human DNA repair-deficient disease that involves transcription coupled repair (TCR), in which three gene products, Cockayne syndrome A (CSA), Cockayne syndrome B (CSB), and ultraviolet stimulated scaffold protein A (UVSSA) cooperate in relieving RNA polymerase II arrest at damaged sites to permit repair of the template strand. Mutation of any of these three genes results in cells with increased sensitivity to UV light and defective TCR. Mutations in CSA or CSB are associated with severe neurological disease but mutations in UVSSA are for the most part only associated with increased photosensitivity. This difference raises questions about the relevance of TCR to neurological disease in CS. We find that CSB-mutated cells, but not UVSSA-deficient cells, have increased levels of intramitochondrial reactive oxygen species (ROS), especially when mitochondrial complex I is inhibited by rotenone. Increased ROS would result in oxidative damage to mitochondrial proteins, lipids, and DNA. CSB appears to behave as an electron scavenger in the mitochondria whose absence leads to increased oxidative stress. Mitochondrial ROS, however, did not cause detectable nuclear DNA damage even when base excision repair was blocked by an inhibitor of polyADP ribose polymerase. Neurodegeneration in Cockayne syndrome may therefore be associated with ROS-induced damage in the mitochondria, independent of nuclear TCR. An implication of our present results is that mitochondrial dysfunction involving ROS has a major impact on CS-B pathology, whereas nuclear TCR may have a minimal role.

Vascular endothelial growth factor-B (VEGF-B is an important member of the VEGF protein family. Recent animal studies indicated that VEGF-B signaling had determinant roles in insulin resistance, lipid distribution and metabolism in type 2 diabetes. The clinical significance of VEGF-B in type 2 diabetes is still not clear. This study aimed to correlate VEGF-B levels with biochemistry characteristics and target organ damage in type 2 diabetic patients. Serum VEGF-B levels were measured using ELISA. A crosssectional control study, which included 180 type 2 diabetic patients and 62 healthy subjects, was carried out. Diabetic patients who were undergoing insulin therapy were not included. This results showed that serum VEGF-B levels did not differ between the type 2 diabetic patients and the healthy controls (169.2&#x2213;118.8 vs 163.5&#x2213;115.2 pg/mL; P=0.734). VEGF-B levels in type 2 diabetic patients were significantly associated with the levels of c-peptide, total cholesterol and triglyceride. T-test analysis showed that the associations of serum VEGF-B levels with insulin resistance, pancreatic reserve, HDL and LDL were not significant. Regression analysis showed that VEGF-B levels were significantly correlated with diabetic retinopathy and nephropathy. No significant association between VEGF-B and macro-vasculopathy was found. In conclusion, our study findings suggested that VEGF-B levels did not differ between the type 2 diabetic patients and the normal controls. High VEGF-B levels might correlate with the presence of hyperlipidemia and target organ damage in type 2 diabetic patients.

The aim of this study was to investigate the short-term effects of green tea consumption on selected salivary defense proteins, antibacterial capacity and anti-oxidation activity in taekwondo (TKD) athletes, following intensive training. Twenty-two TKD athletes performed a 2-hr TKD training session. After training, participants ingested green tea (T, caffeine 6 mg/kg and catechins 22 mg/kg) or an equal volume of water (W). Saliva samples were collected at three time points: before training (BT-T; BT-W), immediately after training (AT-T; AT-W), and 30 min after drinking green tea or water (Rec-T; Rec-W). Salivary total protein, immunoglobulin A (SIgA), lactoferrin, α-amylase activity, free radical scavenger activity (FRSA) and antibacterial capacity were measured. Salivary total protein, lactoferrin, SIgA concentrations and α-amylase activity increased significantly immediately after intensive TKD training. After tea drinking and 30 min rest, α-amylase activity and the ratio of α-amylase to total protein were significantly higher than before and after training. In addition, salivary antibacterial capacity was not affected by intense training, but green tea consumption after training enhanced salivary antibacterial capacity. Additionally, we observed that salivary FRSA was markedly suppressed immediately after training and quickly returned to pre-exercise values, regardless of which fluid was consumed. Our results show that green tea consumption significantly enhances the activity of α-amylase and salivary antibacterial capacity.

Purpose: The development of resistance against anticancer drugs has been a persistent clinical problem for the treatment of locally advanced malignancies in the head and neck mucosal derived squamous cell carcinoma (HNSCC). Recent evidence indicates that the DNA translesion synthesis (TLS) polymerase η (Pol η; hRad30a gene) reduces the effectiveness of gemcitabine/cisplatin. The goal of this study is to examine the relationship between the expression level of Pol η and the observed resistance against these chemotherapeutic agents in HNSCC, which is currently unknown., Methods: Sixty-four mucosal derived squamous cell carcinomas of head and neck (HNSCC) from 1989 and 2007 at the City of Hope National Medical Center (Duarte, CA) were retrospectively analyzed. Pretreatment samples were immunostained with anti-Pol η antibody and the correlation between the expression level of Pol η and clinical outcomes were evaluated. Forty-nine cases treated with platinum (n=40) or gemcitabine (n=9) based chemotherapy were further examined for Pol η expression level for comparison with patient response to chemotherapy., Results: The expression of Pol η was elevated in 67% of the head and neck tumor samples. Pol η expression level was significantly higher in grade 1 to grade 2 tumors (well to moderately differentiated). The overall benefit rate (complete response+ partial response) in patients treated with platinum and gemcitabine based chemotherapy was 79.5%, where low Pol η level was significantly associated with high complete response rate (p=0.03), although not associated with overall survival. Furthermore, no significant correlation was observed between Pol η expression level with gender, age, tobacco/alcohol history, tumor stage and metastatic status., Conclusions: Our data suggest that Pol η expression may be a useful prediction marker for the effectiveness of platinum or gemcitabine based therapy for HNSCC.

Objectives: Neutrophil gelatinase-associated lipocalin (NGAL) and liver-type fatty acid binding protein (L-FABP) are emerging as excellent biomarkers in the urine and plasma for the early prediction of acute and chronic kidney injury. The aims of this prospective study were to determine the role of albuminuria, and that of serum and urine levels of NGAL and L-FABP as predictors of a decline in the glomerular filtration rate (GFR) in patients with type 2 diabetes., Methods: A longitudinal cohort study with one hundred forty type 2 diabetic patients was conducted. Serum and urine levels of NGAL and L-FABP, and the urine albumin excretion rate were determined. The correlation between the kidney injury biomarkers and rate of GFR decline was analyzed., Results: The eGFR of study subjects decreased significantly as the study progressed (86.4±31.1 vs. 74.4±27.3 ml/min/1.73 m(2), P<0.001), and the urine albumin excretion rate increased significantly (264.9±1060.3 vs. 557.7±2092.5 mg/day, P = 0.009). The baseline urine albumin excretion rate and serum L-FABP level were significantly correlated with baseline eGFR (P<0.05). The results of regression analysis for the correlations between the rate of eGFR change and the baseline levels of NGAL and L-FABP, and the urine albumin excretion rate showed that only the urine albumin excretion rate was significantly correlated with the rate of eGFR change (standardized coefficients: -0.378; t: -4.298; P<0.001)., Conclusions: Tubular markers, such as NGAL and L-FABP, may not be predictive factors associated with GFR decline in type 2 diabetic patients.

The aim of this study is to examine the cumulative effects of prolonged intensive training with or without rapid weight changes (RWC) on salivary parameters of elite female Taekwondo (TKD) athletes. Ten elite female Taiwanese TKD athletes (ages: 21.3 ± 1.2 years of age, Ht 164.4 ± 5.6 cm) volunteered to participate in this study. Resting saliva samples were collected at 28-, 14-, 7-, and 1 day before and 1-, 7-, 21 days after a national competition. The levels of salivary immunoglobulin A (sIgA), cortisol, and lactoferrin were measured. In analyzing the anthropometric data, we found that a significant proportion (50%) of elite female TKD athletes had RWC shortly before and after a national competition. The participants were allocated either to the RWC or to the non-RWC group according to their weight change profiles. Our results showed that levels of sIgA and cortisol of athletes with RWC were significantly modulated during the study period. However, athletes without RWC only showed reduced lactoferrin after competition. The results presented here demonstrate that intensive training in combination with RWC affects the mucosal immunity and disrupts the cortisol stress response of elite female TKD athletes., (© 2010 John Wiley & Sons A/S.)

D-501036 is a promising anti-cancer compound that exhibits potent anti-proliferative activity against various types of human cancers through the induction of double strand DNA breaks. To determine drug resistance mechanism related to this class of DNA-damaging agents, a KB-derived D-501036-resistant cell line (S4) was established. Results showed that S4 cells exhibit enhanced DNA rejoining ability as compare to KB cells, through up-regulation of the non-homologous end joining activity. In conclusion, enhancement of NHEJ activity plays important role in the development of D-501036-resistance and targeting NHEJ-related molecules maybe able to overcome drug resistance to DNA damaging agents., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Hypertension is the leading cause of cardiovascular disease worldwide. Long-term arsenic exposure has been linked to increased risk for hypertension; however, little is known whether a previous exposure has lingering effects on hypertension after the exposure being reduced significantly for decades. The study cohort was established in 1990 in an arseniasis-endemic area of 3 villages - Homei, Fuhsin, and Hsinming in Putai Township located on the southwestern coast of Taiwan, where residents were exposed to artesian well water (median level=700 to 930 μg/L) until early 1970s. The original cohort consisted of 490 non-hypertensive residents over 30-yrs-old and 352 of them were successfully followed up in 2002/03. Arsenic concentrations in the artesian well water consumed by residents during 1960s were used to indicate the previous exposure while urinary arsenic species measured in 2002/3 was used to represent current exposure. Hypertension incidences were 27.4, 65.6, and 69.1, per 1000 person-years for men aged 35-49, 50-64, and 65-74 years, respectively being higher than the corresponding rates of 25.1, 46.1, and 57.2 in a community-based longitudinal study. Cancer was the major cause of the total deaths (17/30=57%). Diastolic blood pressure was shown to increase with an increased cumulative arsenic ingestion from drinking water (β=0.27, p<0.001). The incidence was increased by 2.43-fold in subjects of As(V)≥2.67 μg/g creatinine as compared to those of As(V)<1.20 μg/g creatinine (the third vs. first tertile; p=0.047) after adjustment for conventional risk factors. This study suggests that three decades after cessation of drinking artesian well water, residents of the endemic area are still at increased risk for developing hypertension, particularly those who excrete high amounts of As(V)., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The discovery of human DNA polymerase eta (pol η) has a major impact on the fields of DNA replication/repair fields. Since the discovery of human pol η, a number of new DNA polymerases with the ability to bypass various DNA lesions have been discovered. Among these polymerases, pol η is the most extensively studied lesion bypass polymerase with a defined major biological function, that is, to replicate across the cyclobutane pyrimidine dimers introduced by UV irradiation. Cyclobutane pyrimidine dimer is a major DNA lesion that causes distortion of DNA structure and block the replicative DNA polymerases during DNA replication process. Genetic defects in the pol η gene, Rad30, results in a disease called xeroderma pigmentosum variant. This review focuses on the overall properties of pol η and the mechanism that involved in regulating its activity in cells. In addition, the role of pol η in the action of DNA-targeting anticancer compounds is also discussed.

The 4'-thio-β-D-arabinofuranosylcytosine (T-araC) is a newly developed nucleoside analog that has shown promising activity against a broad spectrum of human solid tumors in both cellular and xenograft mice models. TaraC shares similar structure with another anticancer deoxycytidine analog, β-D-arabinofuranosylcytosine (araC, cytarabine), which has been used in clinics for the treatment of acute myelogenous leukemia but has a very limited efficacy against solid tumors. T-araC exerts its anticancer activity mainly by inhibiting replicative DNA polymerases from further extension after its incorporation into DNA. DNA lesion bypass polymerases can manage the DNA lesions introduced by therapeutic agents, such as cisplatin and araC, therefore reduce the activity of these compounds. In this study, the potential relationships between the lesion bypass Y-family DNA polymerases η, ι and κ (pol η, pol ι, and pol κ) and T-araC were examined. Biochemical studies indicated that the triphosphate metabolite of T-araC is a less preferred substrate for the Y-family polymerases. In addition, cell viability study indicated that pol η deficient human fibroblast cells were more sensitive to T-araC when compared with the normal human fibroblast cells. Together, these results suggest that bypass polymerases reduced cell sensitivity to T-araC through helping cells to overcome the DNA damages introduced by T-araC.

Thyroid dysfunction has an important role in renal insufficiency. The aim of the study was to correlate the change of renal function with other clinical factors after thyroxine therapy in hypothyroid patients. A prospective study was designed and 30 hypothyroid patients were included. All study subjects received 0.15-0.2 mg/day thyroxine for 12 weeks. Diastolic blood pressure and serum levels of creatine phosphokinase (CPK) and myoglobulin decreased significantly after thyroxine therapy. Serum creatinine decreased (0.87 ± 0.22 vs. 0.70 ± 0.17 mg/dl, p < 0.001) and estimated glomerular filtration rate (eGFR) increased significantly (82.06 ± 31.08 vs. 100.31 ± 31.79 ml/min/1.73 m(2); p < 0.001) after thyroxine replacement. Left ventricular ejection fraction (LVEF) was significantly increased after thyroxine replacement (64.47 ± 11.94 vs. 72.40 ± 13.89%, p = 0.026). No significant vascular functional changes of peripheral (pulse wave velocity) and renal interlobar arteries (pulsatility index and resistance index) were noted. The change of eGFR significantly correlated with the changes of serum-free T(4) (fT(4)), CPK, myoglobulin and LVEF. The correlation between the change of eGFR and thyroid-stimulating hormone (TSH) level was not significant. In conclusion, the GFR of hypothyroid patients increased significantly after thyroxine replacement. The change of GFR was significantly correlated with the changes of fT(4), CPK, myoglobulin and LVEF, but not with TSH., (Copyright © 2011 S. Karger AG, Basel.)

The anticancer activity of cytarabine (AraC) and gemcitabine (dFdC) is thought to result from chain termination after incorporation into DNA. To investigate their incorporation into DNA at atomic level resolution, we present crystal structures of human DNA polymerase lambda (Pol lambda) bound to gapped DNA and containing either AraC or dFdC paired opposite template dG. These structures reveal that AraC and dFdC can bind within the nascent base pair binding pocket of Pol lambda. Although the conformation of the ribose of AraCTP is similar to that of normal dCTP, the conformation of dFdCTP is significantly different. Consistent with these structures, Pol lambda efficiently incorporates AraCTP but not dFdCTP. The data are consistent with the possibility that Pol lambda could modulate the cytotoxic effect of AraC.

Human DNA polymerase eta (pol eta) can replicate across UV-induced pyrimidine dimers, and defects in the gene encoding pol eta result in a syndrome called xeroderma pigmentosum variant (XP-V). XP-V patients are prone to the development of cancer in sun-exposed areas, and cells derived from XP-V patients demonstrate increased sensitivity to UV radiation and a higher mutation rate compared with wild-type cells. pol eta has been shown to replicate across a wide spectrum of DNA lesions introduced by environmental or chemotherapeutic agents, or during nucleotide starvation, suggesting that the biological roles for pol eta are not limited to repair of UV-damaged DNA. The high error rate of pol eta requires that its intracellular activity be tightly regulated. Here, we show that the phosphorylation of pol eta increased after UV irradiation, and that treatment with caffeine, siRNA against ATR, or an inhibitor of PKC (calphostin C), reduced the accumulation of pol eta at stalled replication forks after UV irradiation or treatment with cisplatin and gemcitabine. Site-specific mutagenesis (S587A and T617A) of pol eta at two putative PKC phosphorylation sites located in the protein-protein interaction domain prevented nuclear foci formation induced by UV irradiation or treatment with gemcitabine/cisplatin. In addition, XP-V cell lines stably expressing either the S587A or T617A mutant form of pol eta were more sensitive to UV radiation and gemcitabine/cisplatin than control cells expressing wild-type pol eta. These results suggest that phosphorylation is one mechanism by which the cellular activity of pol eta is regulated.

Background: We assessed and directly compared weight loss effects of sibutramine and orlistat treatment in a group of obese, poorly-controlled type 2 diabetic patients., Methods: This study recruited 34 diabetic subjects [glycohemoglobin (HbA1c) > 8%] with a body mass index of at least 27 kg/m2. A 36-week, three-phase, prospective, randomized, cross-over comparative study was conducted. In phase 1, 34 patients were randomly divided into two groups. One group received sibutramine for 3 months, then completed a 3 month wash-out period and, finally, shifted to orlistat for another 3 months. The second group followed the same procedure but received orlistat first and then sibutramine. The efficacy measures were rate of weight reduction, glycemic control, insulin sensitivity and cardiovascular risk factors, including waist circumference, lipid profiles and blood pressure., Results: The sibutramine-treated group achieved 2.0 kg (2.5%) weight loss with observable but not statistically significant changes in insulin sensitivity, glycemic control, and cardiovascular risk factors. There were no significant changes in systolic or diastolic blood pressure. The weight reduction in the orlistat-treated group was only 0.8 kg (0.9%), which was significantly less than that of the sibutramine group. There were significant differences in total cholesterol, low density lipoprotein cholesterol and HbA1C. Direct comparative analysis revealed no significant differences between these two groups., Conclusion: This study indicates that sibutramine treatment produced greater reduction in weight than orlistat in obese, poorly-controlled type 2 diabetic patients. However, no significant differences in waist circumference, and lipid or glucose levels were found between the two groups.

D-501036 [2,5-bis(5-hydroxymethyl-2-selenienyl)-3-hydroxymethyl-N-methylpyrrol], a novel selenophene derivative, is a highly potent cytotoxic agent with broad spectrum antitumor activity. The present study was undertaken to explore the mechanism(s) through which D-501036 exerts its action mode on the cancer cell death. D-501036 was found to suppress the growth of KB and HepG(2) cells in an irreversible manner. The results of annexin-V assays and PARP cleavage studies were consistent with the D-501036-induced apoptosis. Findings provided a strong support for the induction of mitochondria-mediated apoptosis by this drug. The examination of two canonical pathways of initiation caspases, those for caspases -8 and -9, revealed that caspase-9 protein and the activities of caspases -9 and -3 were increased in a dose- and time-dependent manner. The concentrations of Fas/Fas-L and procaspase-8 and the activity of caspase-8 were not altered. Furthermore, the mitochondrial membrane potential permeability and the release of cytochrome c to the cytosol were both increased by D-501036. The concentrations of the pro-apoptotic protein Bax and translocation of Bax from the cytosol to the mitochondria were increased in response to D-501036, whereas the concentrations of the anti-apoptotic protein Bcl-2 were decreased. Two DNA damage-related pro-apoptotic proteins, Puma and Noxa, were upregulated in a dose- and time-dependent manner. These pro-apoptotic and anti-apoptotic proteins are downstream effectors of p53. Accordingly, the phosphorylated and total forms of p53 were induced and p53 was translocated from the cytosol to the mitochondria in response to D-501036 treatment. Collectively, we conclude that D-501036 induces cellular apoptosis through the p53-associated mitochondrial pathway.

D-501036 [2,5-bis(5-hydroxymethyl-2-selenienyl)-3-hydroxymethyl-N-methylpyrrole] is herein identified as a novel antineoplastic agent with a broad spectrum of antitumoral activity against several human cancer cells and an IC(50) value in the nanomolar range. The IC(50) values for D-501036 in the renal proximal tubule, normal bronchial epithelial, and fibroblast cells were >10 mumol/L. D-501036 exhibited no cross-resistance with vincristine- and paclitaxel-resistant cell lines, whereas a low level of resistance toward the etoposide-resistant KB variant was observed. Cell cycle analysis established that D-501036 treatment resulted in a dose-dependent accumulation in S phase with concomitant loss of both the G(0)-G(1) and G(2)-M phase in both Hep 3B and A-498 cells. Pulsed-field gel electrophoresis showed D-501036-induced, concentration-dependent DNA breaks in both Hep 3B and A-498 cells. These breaks did not involve interference with either topoisomerase-I and topoisomerase-II function or DNA binding. Rapid reactive oxygen species production and formation of Se-DNA adducts were evident following exposure of cells to D-501036, indicating that D-501036-mediated DNA breaks were attributable to the induction of reactive oxygen species and DNA adduct formation. Moreover, D-501036-induced DNA damage activated ataxia telangiectasia-mutated nuclear protein kinase, leading to hyperphosphorylation of Chk1, Chk2, and p53, decreased expression of CDC25A, and up-regulation of p21(WAF1) in both p53-proficient and p53-deficient cells. Collectively, the results indicate that D-501036-induced cell death was associated with DNA damage-mediated induction of ataxia telangiectasia-mutated activation, and p53-dependent and -independent apoptosis pathways. Notably, D-501036 shows potent activity against the growth of xenograft tumors of human renal carcinoma A-498 cells. Thus, D-501036 is a promising anticancer compound that has strong potential for the management of human cancers.

Genetic defects in polymerase eta (pol eta; hRad30a gene) result in xeroderma pigmentosum variant syndrome (XP-V), and XP-V patients are sensitive to sunlight and highly prone to cancer development. Here, we show that pol eta plays a significant role in modulating cellular sensitivity to DNA-targeting anticancer agents. When compared with normal human fibroblast cells, pol eta-deficient cells derived from XP-V patients were 3-fold more sensitive to beta-d-arabinofuranosylcytosine, gemcitabine, or cis-diamminedichloroplatinum (cisplatin) single-agent treatments and at least 10-fold more sensitive to the gemcitabine/cisplatin combination treatment, a commonly used clinical regimen for treating a wide spectrum of cancers. Cellular and biochemical analyses strongly suggested that the higher sensitivity of XP-V cells to these agents was due to the inability of pol eta-deficient cells to help resume the DNA replication process paused by the gemcitabine/cisplatin-introduced DNA lesions. These results indicated that pol eta can play an important role in determining the cellular sensitivity to therapeutic agents. The findings not only illuminate pol eta as a potential pharmacologic target for developing new anticancer agents but also provide new directions for improving future chemotherapy regimen design considering the use of nucleoside analogues and cisplatin derivatives.

Human DNA apurinic/apyrimidinic endonuclease (APE1) plays a key role in the DNA base excision repair process. In this study, we further characterized the exonuclease activity of APE1. The magnesium requirement and pH dependence of the exonuclease and endonuclease activities of APE1 are significantly different. APE1 showed a similar K(m) value for matched, 3' mispaired, or nucleoside analog beta-l-dioxolane-cytidine terminated nicked DNA as well as for DNA containing a tetrahydrofuran, an abasic site analog. The k(cat) for exonuclease activity on matched, 3' mispaired, and beta-l-dioxolane-cytidine nicked DNA are 2.3, 61.2, and 98.8 min(-1), respectively, and 787.5 min(-1) for APE1 endonuclease. Site-directed APE1 mutant proteins (E96A, E96Q, D210E, D210N, and H309N), which target amino acid residues in the endonuclease active site, also showed significant decrease in exonuclease activity. Gp(4)G was the only potent inhibitor to compete against the substrates of endonuclease and exonuclease activities among all tested naturally occurring ribo-, deoxyribo-nucleoside/nucleotides, NAD(+), NADP(+), and Ap(4)A. The K(i) values of Gp(4)G for the endonuclease and exonuclease activities of APE1 are 10 +/- 0.6 and 1 +/- 0.2 microm, respectively. Given the relative concentrations of Gp(4)G, 3' mispaired, and abasic DNA, Gp(4)G may play an important role in regulating APE1 activity in cells. The data presented here suggest that the APE1 exonuclease and AP endonuclease are two distinct activities. APE1 may exist in two different conformations, and each conformation has a preference for a substrate. The different conformations can be affected by MgCl(2) or salt concentrations.

In an attempt to overcome the cardiotoxicity and cross-resistance problems caused by the anticancer drugs anthracyclines and anthracenediones during chemotherapy, we have developed a series of aza-anthracenedione compounds by modifying the chromophore and the side arms of anthracyclines and anthracenediones. One of these aza-anthracenediones, 6,9-bis[(2-aminoethyl)amino]benzo[g]isoquinoline-5,10-dione (BBR 2778), which is currently under phase II clinical trials, showed remarkable antitumor activity and appeared to lack a cardiotoxic effect in preclinical studies. However, it was still cross-resistant against multidrug resistance (MDR) cells expressing P-glycoprotein (P-gp). In contrast, another aza-anthracenedione, 6,9-bis[[2-(dimethylamino)ethyl]amino]benzo[g]isoquinoline-5,10-dione, which has side arm structures different from those of BBR 2778, was highly active against MDR cells. In this study, BBR 2778, BBR 2378, and an anthracenedione compound, 1,4-bis[(2-aminoethyl)amino]-5,8-dimethyl-9,10-anthracenedione, were used to assess the relationship between the chemical structures of these drugs and their interactions with DNA and P-gp. In addition, the biological and pharmacological influences of photoaffinity labeling were also studied for BBR 2778 and DEH. As the results indicate, the photolabeled analogs of BBR 2778 and DEH were less DNA-reactive and less cytotoxic. The more lipophilic compound, BBR 2378, and the photolabeled analogs of BBR 2778 and DEH inhibited P-gp labeling by azidopine better than did the more hydrophilic parental compounds. These studies suggested that the DNA binding affinity of BBR 2778 and DEH could be important in determining their cytotoxicity, and that the chemical structure of the side arms and the lipophilicity of these drugs are critical in determining their cross-resistance.

Human apurinic/apyrimidinic endonuclease (APE1) is an essential enzyme in DNA base excision repair that cuts the DNA backbone immediately adjacent to the 5' side of abasic sites to facilitate repair synthesis by DNA polymerase beta (ref. 1). Mice lacking the murine homologue of APE1 die at an early embryonic stage. Here we report that APE1 has a DNA exonuclease activity on mismatched deoxyribonucleotides at the 3' termini of nicked or gapped DNA molecules. The efficiency of this activity is inversely proportional to the gap size in DNA. In a base excision repair system reconstituted in vitro, the rejoining of nicked mismatched DNA depended on the presence of APE1, indicating that APE1 may increase the fidelity of base excision repair and may represent a new 3' mispaired DNA repair mechanism. The exonuclease activity of APE1 can remove the anti-HIV nucleoside analogues 3'-azido-3'-deoxythymidine and 2',3'-didehydro-2', 3'-dideoxythymidine from DNA, suggesting that APE1 might have an impact on the therapeutic index of antiviral compounds in this category.

The anthrapyrazoles have entered clinical trials and show significant activity against breast cancer. However, these drugs are cardiotoxic and ineffective in multidrug-resistant (MDR) tumor cells. We have reported previously on the synthesis and antitumor characteristics of the 9-aza-anthrapyrazoles and their lack of cardiotoxicity; unfortunately, the leading candidates are cross-resistant in MDR-expressing cells. The results also indicated that the side arm structures of 9-aza-anthrapyrazole play a critical role in determining the drug resistance in MDR-expressing cells-only compounds that have a tertiary amine on both side arms are not cross-resistant. To further elucidate the biochemical and pharmacological impact of the side arm structures, one of the 9-aza-anthrapyrazole compounds, BBR 3422 [2-(2-aminoethyl)-5-(2-methylaminoethyl)indazolo[4,3-g,h]isoquinoline-6(2H)-one], was selected to be photolabeled with N-hydroxysuccinimidyl-4-azidosalicylic acid (NHS-ASA). In comparison to the parental compound, the photolabeled BBR 3422 was not as cytotoxic or DNA active, but it competed better than the parental compound against azidopine on P-glycoprotein labeling. In addition, confocal microscopic studies showed that BBR 3422 was clustered mainly in the cell nucleus, but its photolabeled analogue was located in the cytoplasm of the human breast cancer cell line MCF-7. Only a trace amount of both compounds was detected in the doxorubicin-derived resistant cell line MCF-7/ADR. The treatment of MCF-7/ADR cells with verapamil increased the intracellular amounts of both compounds.

beta-l-Dioxolane-cytidine (l-OddC, BCH-4556, Troxacitabine) is a novel unnatural stereochemical nucleoside analog that is under phase II clinical study for cancer treatment. This nucleoside analog could be phosphorylated and subsequently incorporated into the 3' terminus of DNA. The cytotoxicity of l-OddC was correlated with the amount of l-OddCMP in DNA, which depends on the incorporation by DNA polymerases and the removal by exonucleases. Here we reported the purification and identification of the major enzyme that could preferentially remove l-OddCMP compared with dCMP from the 3' termini of DNA in human cells. Surprisingly, this enzyme was found to be apurinic/apyrimidinic endonuclease (APE1) (), a well characterized DNA base excision repair protein. APE1 preferred to remove l- over d-configuration nucleosides from 3' termini of DNA. The efficiency of removal of these deoxycytidine analogs were as follows: l-OddC > beta-l-2',3'-dideoxy-2', 3'-didehydro-5-fluorocytidine > beta-l-2',3'-dideoxycytidine > beta-l-2',3'-dideoxy-3'-thiocytidine > beta-d-2',3'-dideoxycytidine > beta-d-2',2'-difluorodeoxycytidine > beta-d-2'-deoxycytidine >/= beta-d-arabinofuranosylcytosine. This report is the first demonstration that an exonuclease can preferentially excise l-configuration nucleoside analogs. This discovery suggests that APE1 could be critical for the activity of l-OddC or other l-nucleoside analogs and may play additional important roles in cells that were not previously known.

The uvsY protein plays essential roles in homologous genetic recombination processes in the bacteriophage T4. In vitro, uvsY promotes the formation of presynaptic filaments containing stoichiometric amounts of the T4 uvsX recombinase bound to single-stranded DNA. uvsY protein has intrinsic binding activities towards ssDNA, uvsX, and gp32, the T4-encoded SSB, however, it has not been directly determined which of these activities are essential for uvsY's role in presynapsis. We have therefore sought to generate altered forms of uvsY deficient in uvsX- and/or gp32-binding, in order to assess whether these specific protein-protein interactions are essential for uvsY recombination functions. Limited chymotrypsinolysis of the 16 kDa uvsY protein generates two major fragments: an 11.5 kDa fragment containing the N-terminus of uvsY, and a 4.5 kDa C-terminal fragment. We have expressed and purified the large fragment as a fusion protein containing the N-terminal 101 amino acids of uvsY. We show that this truncated uvsY species, which we call uvsYNT, retains ssDNA-binding activity, but is devoid of both uvsX- and gp32-binding activities. Like native uvsY, uvsYNT stimulates the ssDNA-dependent ATPase activity of the uvsX protein, however, the synergistic effects observed between uvsY, uvsX, and gp32 are not observed with uvsYNT. In addition, uvsYNT weakly stimulates uvsX-catalyzed DNA strand exchange reactions. The latter result is surprising since it suggests that specific interactions with uvsX and/or gp32 are not absolutely essential for uvsY recombination functions. Taken together, the data are consistent with a model in which uvsY-ssDNA interactions alone are capable of promoting the assembly of functional uvsX-ssDNA complexes, while uvsY-protein interactions stabilize uvsX-ssDNA complexes.