ToxSTAR: drug-induced liver injury prediction tool for the web environment

SUMMARY

Drug-induced liver injury (DILI) is a challenging endpoint in predictive toxicology because of the complex reactive metabolites that cause liver damage and the wide range of mechanisms involved in the development of the disease. ToxSTAR provides structural similarity-based DILI analysis and in-house DILI prediction models that predict four DILI subtypes (cholestasis, cirrhosis, hepatitis and steatosis) based on drug and drug metabolite molecules.

AVAILABILITY AND IMPLEMENTATION

ToxSTAR is freely available at https://toxstar.kitox.re.kr/.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Classification of dog skin diseases using deep learning with images captured from multispectral imaging device

Background

Dog-associated infections are related to more than 70 human diseases. Given that the health diagnosis of a dog requires expertise of the veterinarian, an artificial intelligence model for detecting dog diseases could significantly reduce time and cost required for a diagnosis and efficiently maintain animal health.

Objective

We collected normal and multispectral images to develop classification model of each three dog skin diseases (bacterial dermatosis, fungal infection, and hypersensitivity allergic dermatosis). The single models (normal image- and multispectral image-based) and consensus models were developed used to four CNN model architecture (InceptionNet, ResNet, DenseNet, MobileNet) and select well-performed model.

Results

For single models, such as normal image- or multispectral image-based model, the best accuracies and Matthew’s correlation coefficients (MCCs) for validation data set were 0.80 and 0.64 for bacterial dermatosis, 0.70 and 0.36 for fungal infection, and 0.82 and 0.47 for hypersensitivity allergic dermatosis. For the consensus models, the best accuracies and MCCs for the validation set were 0.89 and 0.76 for the bacterial dermatosis data set, 0.87 and 0.63 for the fungal infection data set, and 0.87 and 0.63 for the hypersensitivity allergic dermatosis data set, respectively, which supported that the consensus models of each disease were more balanced and well-performed.

Conclusions

We developed consensus models for each skin disease for dogs by combining each best model developed with the normal and multispectral images, respectively. Since the normal images could be used to determine areas suspected of lesion of skin disease and additionally the multispectral images could help confirming skin redness of the area, the models achieved higher prediction accuracy with balanced performance between sensitivity and specificity.

Semi-automated approach for generation of biological networks on drug-induced cholestasis, steatosis, hepatitis, and cirrhosis

Drug-induced liver injury (DILI) is one of the leading reasons for discontinuation of a new drug development project. Diverse machine learning or deep learning models have been developed to predict DILI. However, these models have not provided an adequate understanding of the mechanisms leading to DILI. The development of safer drugs requires novel computational approaches that enable the prompt understanding of the mechanism of DILI. In this study, the mechanisms leading to the development of cholestasis, steatosis, hepatitis, and cirrhosis were explored using a semi-automated approach for data gathering and associations. Diverse data from ToxCast, Comparative Toxicogenomic Database (CTD), Reactome, and Open TG-GATEs on reference molecules leading to the development of the respective diseases were extracted. The data were used to create biological networks of the four diseases. As expected, the four networks had several common pathways, and a joint DILI network was assembled. Such biological networks could be used in drug discovery to identify possible molecules of concern as they provide a better understanding of the disease-specific key events. The events can be target-tested to provide indications for potential DILI effects.

Percutaneous coronary intervention in patients with peripheral artery disease and adverse cardiovascular adverse event and bleeding

Background

Peripheral artery disease (PAD) increase the risk of comorbidity and mortality in coronary artery disease (CAD).

Objectives

We evaluate influence of PAD on prognosis in patients undergoing percutaneous coronary intervention (PCI).

Methods

We analyzed all consecutive patients included in our dedicated local registry for PCI between January 2011 and December 2016. Presence of PAD was defined by decreased ankle-brachial index (<0.9). Major adverse cardiovascular event (MACE) was defined as a composite of cardiovascular death, non-fatal myocardial infarct, revascularization, and ischemic stroke. Major bleeding was defined as Bleeding Academic Research Consortium 3 or 5.

Results

Among the 4,747 patients who underwent the PCI, 12.9% (n=610) of PAD were identified. Old age (>60 years), renal dysfunction, reduced ejection fraction, and presence of PAD were predictors with both MACE and major bleeding event. Among them, presence of PAD was an independent risk factor of MACE and major bleeding (MACE, HR 8.26, 95% CI 2.33- 29.41, p=0.036; major bleeding, HR 3.11, 95% CI 1.10–10.63, p=0.040, respectively). The MACE and major bleeding rate at 5-year was significantly increased in patients with PAD (MACE, 30.0% vs. 15.8%, log rank test p<0.001; major bleeding, 6.7 vs. 3.6%, log rank test p=0.003, respectively) (Figure).

Conclusion

Presence of PAD was strongly associated with higher rate of long-term MACE and major bleeding. These findings could have a clinical relevance in requiring individualized pharmacologic strategies to reduce the burden of cardiovascular disease.

Funding Acknowledgement

Type of funding sources: None.

Impact of active and stable cancer on survival in patients undergoing percutaneous coronary intervention

Background

With advances in treatment of ischemic heart disease and cancer treatment, use of percutaneous coronary intervention (PCI) in cancer survivors and patients with active cancer (AC) is expanding.

Objectives

The purpose of this study was to determine the impact of cancer on survival and major cardiovascular events (MACE) in a long-term, single-center cohort of patients treated with PCI.

Methods

Patients treated with PCI between January 2010 and December 2017 were grouped as follows: controls (patients without cancer), stable cancer (SC), and AC. AC was included patients with cancer diagnosed within the past 6 months, patients who had cancer-related therapy within the past 6 months, active metastatic disease, or active recurrence of the cancer. The primary endpoints were 5-year survival and a secondary endpoint was 5-year MACE.

Results

A total of 6,743 patients (age 66±12 years, 68.4% men) treated with PCI were included: 6,404 (95.0%) controls, 245 (3.6%) SC, and 94 (1.4%) AC. Predominant malignancies were gastrointestinal (37.4%), lung (22.7%), and genitourinary cancer (14.7%). No differences were observed between patients with AC, SC and controls regarding 5-year MACE (total MACE, 33.2% vs. 28.1% vs. 17.5%, p=0.072; cardiac death, 13.6% vs. 9.1% vs. 6.7%, p=0.066; non-fatal myocardial infarction, 2.9% vs. 7.5% vs. 7.8%, p=0.820; revascularization, 17.9% vs. 17.6% vs. 11.6%, p=0.794, respectively). Patients with AC and SC had reduced 5-year survival compared with controls (62.0% vs. 81.5% vs. 89.8%, p<0.001) (Figure). AC was associated with a 1.76 (95% CI 1.22 to 2.54, p=0.002) fold increased risk of all-cause 5-year mortality in multivariable adjusted models.

Conclusions

Cumulative incidence of 5-year survival was discriminated by concurrent status of cancer following PCI. Individualized decision making is needed in the routine practice of PCI regarding concurrent cancer-specific treatment and prognosis.

Funding Acknowledgement

Type of funding sources: None.

Development of blood brain barrier permeation prediction models for organic and inorganic biocidal active substances

Biocidal products are broadly used in homes and industries. However, the safety of biocidal active substances (BASs) is not yet fully understood. In particular, the neurotoxic action of BASs needs to be studied as diverse epidemiological studies have reported associations between exposure to BASs and neural diseases. In this study, we developed in silico models to predict the blood-brain barrier (BBB) permeation of organic and inorganic BASs. Due to a lack of BBB data for BASs, the chemical space of BASs and BBB dataset were compared in order to select BBB data that were structurally similar to BASs. In silico models to predict log-scaled BBB penetration were developed using support vector regression for organic BASs and multiple linear regression for inorganic BASs. The model for organic BASs was developed with 231 compounds (training set: 153 and test set: 78) and achieved good prediction accuracy on an external test set (R² = 0.64), and the model outperformed the model for pharmaceuticals. The model for inorganic BASs was developed with 11 compounds (R² = 0.51). Applicability domain (AD) analysis of the models clarified molecular structures reliably predicted by the models. Therefore, the models developed in this study can be used for predicting BBB permeable BASs in human. These models were developed according to the Quantitative Structure-Activity Relationship validation principles proposed by the Organization for Economic Cooperation and Development.

Acetylcholinesterase and monoamine oxidase-B inhibitory activities by ellagic acid derivatives isolated from Castanopsis cuspidata var. sieboldii

Among 276 herbal extracts, a methanol extract of Castanopsis cuspidata var. sieboldii stems was selected as an experimental source for novel acetylcholinesterase (AChE) inhibitors. Five compounds were isolated from the extract by activity-guided screening, and their inhibitory activities against butyrylcholinesterase (BChE), monoamine oxidases (MAOs), and β-site amyloid precursor protein cleaving enzyme 1 (BACE-1) were also evaluated. Of these compounds, 4'-O-(α-L-rhamnopyranosyl)-3,3',4-tri-O-methylellagic acid (3) and 3,3',4-tri-O-methylellagic acid (4) effectively inhibited AChE with IC₅₀ values of 10.1 and 10.7 µM, respectively. Ellagic acid (5) inhibited AChE (IC₅₀ = 41.7 µM) less than 3 and 4. In addition, 3 effectively inhibited MAO-B (IC₅₀ = 7.27 µM) followed by 5 (IC₅₀ = 9.21 µM). All five compounds weakly inhibited BChE and BACE-1. Compounds 3, 4, and 5 reversibly and competitively inhibited AChE, and were slightly or non-toxic to MDCK cells. The binding energies of 3 and 4 (- 8.5 and - 9.2 kcal/mol, respectively) for AChE were greater than that of 5 (- 8.3 kcal/mol), and 3 and 4 formed a hydrogen bond with Tyr124 in AChE. These results suggest 3 is a dual-targeting inhibitor of AChE and MAO-B, and that these compounds should be viewed as potential therapeutics for the treatment of Alzheimer's disease.

Selective Inhibition of Human Monoamine Oxidase B by 5-hydroxy-2-methyl-chroman-4-one Isolated from an Endogenous Lichen Fungus Daldinia fissa

Inhibitory activities against monoamine oxidases (MAOs) and cholinesterases (ChEs) and antioxidant activity were evaluated for 195 extracts from Ukraine-derived endogenous lichen fungi (ELF). Among them, an ELF13 (identified as Daldinia fissa) extract showed the highest inhibitory activity against MAO-B, and 5-hydroxy-2-methyl-chroman-4-one (HMC) was isolated as a ~ 4-fold selective inhibitor of MAO-B (IC₅₀ = 3.23 µM) compared to MAO-A (IC₅₀ = 13.97 µM). HMC is a reversible competitive inhibitor with a K_i value of 0.896 µM. No cytotoxicity was observed in normal and cancer cells at 50 µM of HMC. HMC showed blood–brain barrier permeability and high gastrointestinal absorption in silico pharmacokinetics. The docking simulation results showed that the binding affinity of HMC for MAO-B (−7.3 kcal/mol) was higher than that of MAO-A (−6.1 kcal/mol) and that HMC formed a hydrogen bond interaction with Cys172 of MAO-B (distance: 3.656 Å), whereas no hydrogen bonding was predicted with MAO-A. These results suggest that HMC can be considered a candidate for the treatment of neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease.

Inhibitory Effect of Sesamolin on Melanogenesis in B16F10 Cells Determined by In Vitro and Molecular Docking Analyses

BACKGROUND

Melanin protects the skin against the harmful effects of ultraviolet irradiation. However, melanin overproduction can result in several aesthetic problems, including melasma, freckles, age spots and chloasma. Therefore, development of anti-melanogenic agents is important for the prevention of serious hyperpigmentation diseases. Sesamolin is a lignan compound isolated from sesame seeds with several beneficial properties, including potential for melanin inhibition.

OBJECTIVE

The aim of this study was to evaluate the anti-melanogenic effect of sesamolin in cell culture in vitro and the underlying mechanism of inhibition using molecular docking simulation.

METHODS

Melanogenesis was induced by 3-isobutyl-1-methylxanthine in B16F10 melanoma cells, and the inhibitory effects of sesamolin were evaluated using zymography, a tyrosinase inhibitory activity assay, western blotting, and real-time reverse transcription-polymerase chain reaction analysis. Docking simulations between sesamolin and tyrosinase were performed using Autodock vina.

RESULTS

Sesamolin significantly inhibited the expression of melanogenesis-related factors tyrosinase, and tyrosinase-related proteins 1 and 2 at the mRNA and protein levels. Treatment of melanoma cells with 50 µM sesamolin demonstrated the strongest inhibition against intercellular tyrosinase and melanin synthesis without exerting cytotoxic effects. Sesamolin significantly reduced mushroom tyrosinase activity in a dose-dependent manner via a competitive inhibition mechanism. Tyrosinase docking simulations supported that sesamolin (-6.5 kcal/mol) bound to the active site of tyrosinase more strongly than the positive control (arbutin, -5.7 kcal/mol).

CONCLUSION

Sesamolin could be developed as a melanogenesis inhibiting agent owing to its dual function in blocking the generation of melanogenesis-related enzymes and inhibiting the enzymatic response of tyrosinase.

Development of Prediction Models for Drug-Induced Cholestasis, Cirrhosis, Hepatitis, and Steatosis Based on Drug and Drug Metabolite Structures

Drug-induced liver injury (DILI) is one of the major reasons for termination of drug development. Due to the importance of predicting DILI in early phases of drug development, diverse in silico models have been developed to filter out DILI-causing candidates before clinical study. However, no computational models have achieved sufficient prediction power for screening DILI in early phases because 1) drugs often cause liver injury through reactive metabolites, 2) different clinical outcomes of DILI have different mechanisms, and 3) the DILI label on drugs is not clearly defined. In this study, we developed binary classification models to predict drug-induced cholestasis, cirrhosis, hepatitis, and steatosis based on the structure of drugs and their metabolites. DILI-positive data was obtained from post-market reports of drugs and DILI-negative data from DILIrank, a database curated by the Food and Drug Administration (FDA). Support vector machine (SVM) and random forest (RF) were used in developing models with nine fingerprints and one 2D molecular descriptor calculated from drug (152 DILI-positives and 102 DILI-negatives) and drug metabolite (192 DILI-positives and 126 DILI-negatives) structures. Models were developed according to Organisation for Economic Co-operation and Development (OECD) guidelines for quantitative structure-activity relationship (QSAR) validation. Internal and external validation was performed with a randomization test in order to thoroughly examine model predictability and avoid random correlation between structural features and adverse outcomes. The applicability domain was defined with a leverage method for reliable prediction of new chemicals. The best models for each liver disease were selected based on external validation results from drugs (cholestasis: 70%, cirrhosis: 90%, hepatitis: 83%, and steatosis: 85%) and drug metabolites (cholestasis: 86%, cirrhosis: 88%, hepatitis: 86%, and steatosis: 83%) with applicability domain analysis. Compiled data sets were further exploited to derive privileged substructures that were more frequent in DILI-positive sets compared to DILI-negative sets and in drug metabolite structures compared to drug structures with a Morgan fingerprint level 2.

P1416 Clinical importance of consecutive transthoracic echocardiography in the patients with hypertrophic cardiomyopathy

Funding Acknowledgements

nothing

OnBehalf

nothing

Background

prediction of outcomes Hypertrophic cardiomyopathy (HCM) have been robustly analyzed with echocardiography. However, there is limited data of serial follow-up (FU) transthoracic echocardiography (TTE) to predict outcomes in patients with HCM.

Objectives

This study aim is to discover clinical predictors associated with consecutive TTE follow-up in patients with HCM.

Methods

From 2010 to 2016, 162 patients with HCM were enrolled retrospectively. Concentric LVH and others systolic disease related to wall thickness were excluded. Index TTE (baseline) was measured when firstly admitted in our hospital. FU TTE was analyzed at the end of follow-up, defined as the last recorded value in patients who did not develop events or the last recorded value before events developed.

Results

The average of FU TTE and clinical FU period was 3.7 ± 2.0 years. Clinical outcomes were defined as stroke, syncope, heart failure, arrhythmia and death. Interestingly, only baseline TR V max was a predictor for clinical outcome whereas the others echo parameters were not associated with events (Table 1). KM curve showed the TR Vmax ≥2.5m/s was also significant (log rank = 0.008, Fig 1.)

Conclusions Our study showed short-term FU TTE did not bring clinician with clinical benefits in the aspect of prediction for events. Only baseline TR V max was good correlation with cardiovascular outcomes and even in the survival analysis.

Serial TTE and changed values Total N = 162 index TTE (baseline) FU TTE Change of FU per year event no event p-value event no event p-value event no event p-value IVDd, mm 14 ± 4 15 ± 5 0.500 15 ± 5 14 ± 5 0.758 0.23 ± 0.51 -0.07 ± 1.27 0.200 LVIDd, mm 47 ± 5 48 ± 6 0.256 47 ± 7 48 ± 6 0.560 -0.22 ± 2.79 0.10 ± 2.27 0.444 LVEF, % 62 ± 5 61 ± 7 0.379 61 ± 6 61 ± 10 0.927 -0.43 ± 3.10 -0.04 ± 4.94 0.620 LAVI 43 ± 9 43 ± 8 0.879 57 ± 27 58 ± 23 0.849 0.53 ± 14.5 3.11 ± 7.2 0.134 EA ratio 0.9 ± 0.6 0.9 ± 0.6 0.782 1.0 ± 0.8 0.9 ± 0.6 0.595 -0.02 ± 0.76 0.003 ± 0.027 0.594 DT,ms 196 ± 58 201 ± 62 0.603 203 ± 91 217 ± 89 0.370 17 ± 57 5 ± 40 0.154 septal e` 4.4 ± 2.1 4.2 ± 1.6 0.585 4.4 ± 1.6 4.6 ± 1.7 0.438 0.24 ± 0.91 0.05 ± 0.65 0.190 E of e` 17 ± 11 17 ± 23 0.993 15 ± 9 15 ± 6 0.726 -0.48 ± 4.42 -1.66 ± 22.78 0.728 TR velocity 2.6 ± 0.5 2.4 ± 0.4 0.012 2.7 ± 0.6 2.6 ± 0.4 0.604 0.05 ± 0.30 0.04 ± 0.18 0.905 Max wall thickness 17 ± 3 18 ± 3 0.137 17 ± 4 17 ± 3 0.888 -0.01 ± 2.19 -0.18 ± 1.14 0.522

Abstract P1416 Figure. TR Vmax and CV outcomes in the KM curve

P3637Relationship between serial measurements of NT-proBNP and cardiovascular events in patients with acute coronary syndrome

Background

Increased level of natriuretic peptides has been known as an important predictors of adverse cardiovascular (CV) outcomes in patients with acute coronary syndrome (ACS). We sought to evaluate clinical implication of N-terminal pro-brain natriuretic peptide (NT-proBNP) measured at initial and follow-up periods.

Methods

Serial NT-proBNP levels (on-admission and one-month post-PCI) were measured in ACS patients undergoing PCI (n=2,290). High NT-proBNP levels were determined according to the predefined age-specific criteria. Patients were stratified into 4 groups according to NT-proBNP levels (on-admission & one-month): (1) normal-normal group (n=1234, 53.9%); (2) high–normal group (n=257, 11.2%); (3) normal-high group (n=376, 16.4%); and (4) high-high group (n=423, 18.5%). Clinical events were defined as all-cause death and MACE (a composite of CV death, non-fatal MI, and ischemic stroke).

Results

With a median follow-up of 35.9 (IQR: 16.8, 54.5) months, all-cause death and MACE were occurred in 4.1% and 7.2%, respectively. NT-proBNP on-admission vs. at one-month did not differ significantly (median 391.6 [IQR: 143.9, 1402.3] vs. median 619.1 [IQR 240.1, 1616.1]; p=0.622), but the prevalence of high NT-proBNP was increased over time (25.3% to 34.9%; p<0.001). The rates of all-cause death and MACE significantly increased only in the high-high group compared with other groups (log-rank test, all p values <0.001, Figure). After adjustment, the high-high group remained significantly risky in terms with the occurrence of all-cause death (HR, 2.99; 95% CI, 1.65 to 5.41; p<0.001) and MACE (HR, 1.96; 95% CI, 1.28 to 3.01; p=0.002).

Figure 1

Conclusion

Serial measurements of NT-proBNP at on-admission and follow-up can help to stratify the risks of all-cause death and adverse CV events following PCI in ACS patients. About two-fifths of patients having high NT-proBNP level during hospitalization can be classified into the low-risk group for all-cause death and adverse CV events.

Acknowledgement/Funding

None

RE-ORGA, a Korean Herb Extract, Can Prevent Hair Loss Induced by Dihydrotestosterone in Human Dermal Papilla Cells

Background

Androgenic alopecia (AGA) is the most common type of hair loss. It is likely inherited genetically and is promoted by dihydrotestosterone. 5α-reductase has been proven a good target through finasteride use. However, the pathogenesis of AGA cannot be fully explained based only on dihydrotestosterone levels.

Objective

To identify similar hairloss inhibition activity of RE-ORGA with mode of action other than finasteride.

Methods

We prepared RE-ORGA from Korean herb mixtures. We performed MTT assays for cytotoxicity, Cell Counting Kit-8 assays for cell proliferation, and western blot to identify expression levels of 5α-reductase and Bax. RNA-sequencing was performed for the expression patterns of genes in dihydrotestosterone-activated pathways. Anti-inflammatory activity was also assessed by the expression levels of tumor necrosis factor-alpha (TNF-α) and interleukin 6.

Results

REORGA could promote the proliferation of human dermal papilla cells and showed low cytotoxicity. It also inhibited the expression of 5α-reductases and Bax in the cells. RNA-sequencing results verified that the mRNA expressions of SRD5A1, Bax, transforming growth factor-beta 1 (TGF-β1), and TGF-β1 induced transcript 1 (TGFβ1I1) were decreased, whereas expression of protein tyrosine kinase 2 beta (PTK2β) was more elevated. REORGA also showed anti-inflammatory activity through decreased mRNA levels of TNF-α.

Conclusion

Transcriptionally, up-regulation of PTK2β and concomitant down-regulation of TGFβ1I1 imply that RE-ORGA can modulate androgen receptor sensitivity, decreasing the expression of 5α-reductase type II and Bax together with TGF-β1 transcripts; RE-ORGA also showed partial anti-inflammatory activity. Overall, RE-ORGA is expected to alleviate hair loss by regulating 5α-reductase activity and the receptor's androgen sensitivity.

Potent inhibition of acetylcholinesterase by sargachromanol I from Sargassum siliquastrum and by selected natural compounds

Six hundred forty natural compounds were tested for acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities. Of those, sargachromanol I (SCI) and G (SCG) isolated from the brown alga Sargassum siliquastrum, dihydroberberine (DB) isolated from Coptis chinensis, and macelignan (ML) isolated from Myristica fragrans, potently and effectively inhibited AChE with IC50 values of 0.79, 1.81, 1.18, and 4.16 µM, respectively. SCI, DB, and ML reversibly inhibited AChE and showed mixed, competitive, and noncompetitive inhibition, respectively, with Ki values of 0.63, 0.77, and 4.46 µM, respectively. Broussonin A most potently inhibited BChE (IC50 = 4.16 µM), followed by ML, SCG, and SCI (9.69, 10.79, and 13.69 µM, respectively). In dual-targeting experiments, ML effectively inhibited monoamine oxidase B with the greatest potency (IC50 = 7.42 µM). Molecular docking simulation suggested the binding affinity of SCI (-8.6 kcal/mol) with AChE was greater than those of SCG (-7.9 kcal/mol) and DB (-8.2 kcal/mol). Docking simulation indicated SCI interacts with AChE at Trp81, and that SCG interacts at Ser119. No hydrogen bond was predicted for the interaction between AChE and DB. This study suggests SCI, SCG, DB, and ML be viewed as new reversible AChE inhibitors and useful lead compounds for the development for the treatment of Alzheimer's disease.

Potent and selective inhibition of human monoamine oxidase-B by 4-dimethylaminochalcone and selected chalcone derivatives

Six synthetic (1-6) and six natural (7-12) chalcones were tested for human monoamine oxidases (hMAOs) and acetylcholinesterase (AChE) inhibitory activities. Compounds 4-dimethylaminochalcone (2), 4'-chloro-4-dimethylaminochalcone (5), and 2,4'-dichloro-4-dimethylaminochalcone (1) potently inhibited hMAO-B with IC₅₀ values of 0.029, 0.061, and 0.075 μM, respectively. 4-Nitrochalcone (4) and 4-chlorochalcone (3) also potently inhibited hMAO-B with IC₅₀ values of 0.066 and 0.082 μM, respectively (2.3- and 2.6-fold less than compound 2). Compound 2 had a high selectivity index (113.1) for hMAO-B over hMAO-A (IC₅₀ = 3.28 μM). Compounds 1 and 2,2'-dihydroxy-4',6'-dimethoxychalcone (12) potently inhibited hMAO-A with IC₅₀ values of 0.18 and 0.39 μM, respectively. In addition, compounds 4 and 2 also effectively inhibited AChE with IC₅₀ values of 1.25 and 6.07 μM, respectively, and thus, exhibited dual-targeting. Compound 2 reversibly and competitively inhibited hMAO-B with a K_i value of 0.0066 μM. Docking simulations showed binding affinities of compounds 1 to 5 for hMAO-B were higher than those for hMAO-A or AChE and suggested these five chalcones form hydrogen bonds with MAO-B at Cys172 but that they do not form hydrogen bonds with hMAO-A or AChE. These findings suggest compound 2 be considered a promising and dual-targeting lead compound for the treatment of Alzheimer's disease.

Rhamnocitrin isolated from Prunus padus var. seoulensis: A potent and selective reversible inhibitor of human monoamine oxidase A

Three flavanones and two flavones were isolated from the leaves of Prunus padus var. seoulensis by the activity-guided screening for new monoamine oxidase (MAO) inhibitors. Among the compounds isolated, rhamnocitrin (5) was found to potently and selectively inhibit human MAO-A (hMAO-A, IC₅₀ = 0.051 µM) and effectively inhibit hMAO-B (IC₅₀ = 2.97 µM). The IC₅₀ value of 5 for hMAO-A was the lowest amongst all natural flavonoids reported to date, and the potency was 20.2 times higher than that of toloxatone (1.03 µM), a marketed drug. In addition, 5 reversibly and competitively inhibited hMAO-A and hMAO-B with K_i values of 0.030 and 0.91 µM, respectively. Genkwanin (4) was also observed to strongly inhibit hMAO-A and hMAO-B (IC₅₀ = 0.14 and 0.35 µM, respectively), and competitively inhibit hMAO-A and hMAO-B (K_i = 0.097 and 0.12 µM, respectively). Molecular docking simulation reveals that the binding affinity of 5 with hMAO-A (-18.49 kcal/mol) is higher than that observed with hMAO-B (0.19 kcal/mol). Compound 5 interacts with hMAO-A at four possible residues (Asn181, Gln215, Thr336, and Tyr444), while hMAO-B forms a single hydrogen bond at Glu84. These findings suggest that compound 5 as well as 4 can be considered as novel potent and reversible hMAO-A and/or hMAO-B inhibitors or useful lead compounds for future development of hMAO inhibitors in neurological disorder therapies.

Selective inhibition of monoamine oxidase A by hispidol

Hispidol, an aurone, isolated from Glycine max Merrill, was found to potently and selectively inhibit an isoform of recombinant human monoamine oxidase-A (MAO-A), with an IC₅₀ value of 0.26 µM, and to inhibit MAO-B, but with lower potency (IC₅₀ = 2.45 µM). Hispidol reversibly and competitively inhibited MAO-A with a K_i value of 0.10 µM with a potency much greater than toloxatone (IC₅₀ = 1.10 µM), a marketed drug. It also reversibly and competitively inhibited MAO-B (K_i = 0.51 µM). Sulfuretin, an analog of hispidol, effectively inhibited MAO-A (IC₅₀ = 4.16 µM) but not MAO-B (IC₅₀ > 80 µM). A comparison of their chemical structures showed that the 3'-hydroxyl group of sulfuretin might reduce its inhibitory activities against MAO-A and MAO-B. Flexible docking simulation revealed that the binding affinity of hispidol for MAO-A (-9.1 kcal/mol) was greater than its affinity for MAO-B (-8.7 kcal/mol). The docking simulation showed hispidol binds to the major pocket of MAO-A or MAO-B. The findings suggest hispidol is a potent, selective, reversible inhibitor of MAO-A, and that it be considered a novel lead compound for development of novel reversible inhibitors of MAO-A.

Assessing the safety of an Ephedrae Herba aqueous extract in rats: A repeat dose toxicity study

Ephedrae Herba (EH) has been used in Asian traditional herbal medicine to cure bronchial asthma, cold, flu, chills, fever, headache, nasal congestion, and cough. In this study, we evaluated the subchronic toxicity of an Ephedrae Herba aqueous extract (EHAE) in male and female F344 rats. The EHAE was administered orally daily at doses of 0, 125, 250, 500, and 1000 mg/kg bw/day for 13 weeks. Toxicological assessment was performed to determine mortality, clinical signs, and changes in body weight, food consumption, ophthalmological, urinary, hematological, and serum biochemical parameters, macroscopic and microscopic evaluations, and organ weights. We found that oral administration of EHAE to F344 rats for 13 weeks resulted in histopathological changes in the kidneys and salivary glands. In the kidneys, increased incidence and severity of tubular basophilia were observed in females administered 1000 mg/kg bw/day of the extract. In the salivary glands, acinar cell hypertrophy was observed in males administered 500 mg/kg bw/day and in both sexes administered 1000 mg/kg bw/day of the extract. All test article-treated groups of males and females administered ≥250 mg/kg bw/day showed increased absolute and relative salivary gland weights. Therefore, the NOAEL (No Observed Adverse Effect Level) was determined as 125 mg/kg bw/day for both sexes of rats under the present experimental conditions.

Selective inhibition of monoamine oxidase A by purpurin, an anthraquinone

Monoamine oxidase (MAO) catalyzes the oxidation of monoamines that act as neurotransmitters. During a target-based screening of natural products using two isoforms of recombinant human MAO-A and MAO-B, purpurin (an anthraquinone derivative) was found to potently and selectively inhibit MAO-A, with an IC50 value of 2.50μM, and not to inhibit MAO-B. Alizarin (also an anthraquinone) inhibited MAO-A less potently with an IC50 value of 30.1μM. Furthermore, purpurin was a reversible and competitive inhibitor of MAO-A with a Ki value of 0.422μM. A comparison of their chemical structures suggested the 4-hydroxy group of purpurin might play an important role in its inhibition of MAO-A. Molecular docking simulation showed that the binding affinity of purpurin for MAO-A (-40.0kcal/mol) was higher than its affinity for MAO-B (-33.9kcal/mol), and that Ile 207 and Gly 443 of MAO-A were key residues for hydrogen bonding with purpurin. The findings of this study suggest purpurin is a potent, selective, reversible inhibitor of MAO-A, and that it be considered a new potential lead compound for development of novel reversible inhibitors of MAO-A (RIMAs).

Potent selective monoamine oxidase B inhibition by maackiain, a pterocarpan from the roots of Sophora flavescens

Monoamine oxidase (MAO) catalyzes the oxidation of monoamines and its two isoforms, MAO-A and MAO-B, break down neurotransmitter amines. Of the compounds isolated from the roots of Sophora flavescens, (-)-maackiain (4), a pterocarpan, was found to potently and selectively inhibit human MAO-B, with an IC50 of 0.68μM, and to have a selectivity index of 126.2 for MAO-B. As compared with other herbal natural products, the IC50 value of 4 for MAO-B is one of the lowest reported to date. Genistein (1) highly, effectively and non-selectively inhibited MAO-A and MAO-B with IC50 values of 3.9μM and 4.1μM, respectively. (-)-4-Hydroxy-3-methoxy-8,9-methylenedioxypterocarpan (2) effectively and non-selectively inhibited MAO-A and MAO-B with IC50 values of 20.3μM and 10.3μM, respectively. In addition, compound 4 reversibly and competitively inhibited MAO-B with a Ki value of 0.054μM. Molecular docking simulation revealed that the binding affinity of 4 for MAO-B (-26.6kcal/mol) was greater than its affinity for MAO-A (-8.3kcal/mol), which was in-line with our inhibitory activity findings. Furthermore, Cys172 of MAO-B was found to be a key residue for hydrogen bonding with compound 4. The findings of this study suggest compound 4 be viewed as a new potent, selective, and reversible MAO-B inhibitor, and that compounds 1 and 2 be considered useful lead compounds for the developments of nonselective and reversible MAO inhibitors for the treatment of disorders like Parkinson's disease, Alzheimer disease, and depression.

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

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

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

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

Fabrication and radio frequency characterization of carbon nanotube field effect transistor: evidence of quantum capacitance

We fabricated an radio frequency (RF) carbon nanotube field effect transistor (CNTFET) whose electrode shapes were standard RF designed ground-signal-ground (GSG)-type pads. The S-parameters measured from our RF CNTFET in the frequency range up to 6 GHz were fitted with an RF equivalent circuit, and the extracted gate capacitance was shown to be the capacitance value of the series combination of the electrostatic capacitance and the quantum capacitance. The effect of the channel resistance and the kinetic inductance was also discussed.

Association between levels of physical activity and poor self-rated health in Korean adults: The Third Korea National Health and Nutrition Examination Survey (KNHANES), 2005

OBJECTIVE

To investigate the association between level of physical activity and poor self-rated health in Korean adults.

STUDY DESIGN

A cross-sectional study was conducted on 7,800 adults aged > or =19 years who completed the Health Interview and the Health Behavior Surveys, issued during the Third National Health and Nutrition Examination Survey (2005).

METHODS

The association between self-rated health and physical activity was tested using Chi-squared test. Multiple logistic regression analysis was used to calculate the odds ratios of poor self-rated health for different levels of physical activity after adjusting for physical and chronic medical conditions.

RESULTS

The prevalence of poor self-rated health was significantly lower as the level of physical activity increased, and odds ratios for poor self-rated health were significantly lower for higher levels of physical activity after adjusting for age, marital status, educational status, smoking, alcohol consumption, and the number of physical impairments and chronic medical conditions. The association was similar in different age groups and among healthy respondents and respondents with physical impairments or chronic medical conditions.

CONCLUSIONS

Physical activity was positively associated with self-rated health in Koreans. The independent association between a lower level of physical activity and poor self-rated health supports public health programmes that encourage regular physical activity.

Study of a BALB/c Mouse Model for Allergic Asthma

Allergic asthma is a worldwide public health problem and a major socioeconomic burden disease. It is a chronic inflammatory disease marked by airway eosinophilia and goblet cell hyperplasia with mucus hypersecretion. Mouse models have proven as a valuable tool for studying human asthma. In the present report we describe a comparison of mouse asthma models. The experiments were designed as follows: Group I was injected with ovalbumin (OVA, i.p.) on day 1 and challenged with 1% OVA (aerosol exposure) on days 14~21. Group II was injected on day 1, 14 and aerosol-immunized on days 14~21. Group III was injected on day 1, 14 and immunized by 1% OVA aerosol on days 18~21. We assessed asthma induction by determining the total number of white blood cells (WBC) and eosinophils as well as by measuring cytokine levels in bronchoalveolar lavage fluid (BALF). In addition, we evaluated the histopathological changes of the lungs and determined the concentration of immunoglobulin E (IgE) in serum. Total WBC, eosinophils, Th2 cytokines (IL-4, IL-13) and IgE were significantly increased in group I relative to the other groups. Moreover, histopathological studies show that group I mice show an increase in the infiltration of inflammatory cell-in peribronchial and perivascular areas as well as an overall increase in the number of mucus-containing goblet cells relative to other groups. These data suggest that group I can be a useful model for the study of human asthma pathobiology and the evaluation of existing and novel therapeutic agents.

Fabrication of one-dimensional devices by a combination of AC dielectrophoresis and electrochemical deposition

We demonstrate a hybrid process for fabricating one-dimensional wire devices. The process is a combination of an alignment procedure using dielectrophoresis and subsequent contact metal formation utilizing electrochemical deposition with non-toxic organic-based Au electrolytes. Several devices have been successfully made from GaN nanowires or multi-walled carbon nanotubes (MWCNTs) using our hybrid technique. We demonstrate that rapid thermal annealing improves the ohmic characteristics by five orders of magnitude in the case of the GaN devices and ∼300% in the case of the MWCNT devices. One of the reasons for this improvement is enhanced gold wetting due to the reduction of grain size at the annealing temperature.

Morphological and photoelectrochemical characterization of core-shell nanoparticle films for dye-sensitized solar cells: Zn-O type shell on SnO2 and TiO2 cores

Core-shell type nanoparticles with SnO2 and TiO2 cores and zinc oxide shells were prepared and characterized by surface sensitive techniques. The influence of the structure of the ZnO shell and the morphology ofnanoparticle films on the performance was evaluated. X-ray absorption near-edge structure and extended X-ray absorption fine structure studies show the presence of thin ZnO-like shells around the nanoparticles at low Zn levels. In the case of SnO2 cores, ZnO nanocrystals are formed at high Zn/Sn ratios (ca. 0.5). Scanning electron microscopy studies show that Zn modification of SnO2 nanoparticles changes the film morphology from a compact mesoporous structure to a less dense macroporous structure. In contrast, Zn modification of TiO2 nanoparticles has no apparent influence on film morphology. For SnO2 cores, adding ZnO improves the solar cell efficiency by increasing light scattering and dye uptake and decreasing recombination. In contrast, adding a ZnO shell to the TiO2 core decreases the cell efficiency, largely owing to a loss of photocurrent resulting from slow electron transport associated with the buildup of the ZnO surface layer.

Biochemical and biophysical evidence for gamma 2 subunit association with neuronal voltage-activated Ca2+ channels

A novel gene (Cacng2; gamma(2)) encoding a protein similar to the voltage-activated Ca(2+) channel gamma(1) subunit was identified as the defective gene in the epileptic and ataxic mouse, stargazer. In this study, we analyzed the association of this novel neuronal gamma(2) subunit with Ca(2+) channels of rabbit brain, and the function of the gamma(2) subunit in recombinant neuronal Ca(2+) channels expressed in Xenopus oocytes. Our results showed that the gamma(2) subunit and a closely related protein (called gamma(3)) co-sedimented and co-immunoprecipitated with neuronal Ca(2+) channel subunits in vivo. Electrophysiological analyses showed that gamma(2) co-expression caused a significant decrease in the current amplitude of both alpha(1B)(alpha(1)2.2)-class (36.8%) and alpha(1A)(alpha(1)2.1)-class (39.7%) Ca(2+) channels (alpha(1)beta(3)alpha(2)delta). Interestingly, the inhibitory effects of the gamma(2) subunit on current amplitude were dependent on the co-expression of the alpha(2)delta subunit. In addition, co-expression of gamma(2) or gamma(1) also significantly decelerates the activation kinetics of alpha(1B)-class Ca(2+) channels. Taken together, these results suggest that the gamma(2) subunit is an important constituent of the neuronal Ca(2+) channel complex and that it down-regulates neuronal Ca(2+) channel activity. Furthermore, the gamma(2) subunit likely contributes to the fine-tuning of neuronal Ca(2+) channels by counterbalancing the effects of the alpha(2)delta subunit.

Meta-analysis of hypertension as a risk factor of cerebrovascular disorders in Koreans

This study was conducted to integrate the results of previous studies which evaluated hypertension as a risk factor for cerebrovascular disorders (CVD) in Koreans. We retrieved the Korean literature using a manual search and the English literature using the MEDLINE database concerning the relationship between hypertension and CVD in Koreans from 1980 to 1997. The overall effect size of hypertension as a risk factor of CVD was represented by common odds ratio (OR). Before the integration of each effect size, a heterogeneity test and a sensitivity test was conducted. The materials were nine published epidemiologic studies with a total of 2,271 cases of CVD. The common ORs (95% confidence interval) of overall CVD, hemorrhagic CVD and ischemic CVD associated with hypertension were 4.10 (3.56-4.71), 6.56 (4.92-8.80) and 3.28 (2.77-3.90), respectively. Thus, the common OR of hemorrhagic CVD associated with hypertension was significantly higher than that of overall or ischemic CVD. This suggests that hypertension is an important risk factor for overall CVD and its subtypes in Koreans. Due to the lack of reliable prospective studies, however, longitudinal study is required in this area.

Generalized interframe vertex-based shape encoding scheme for video sequences

The efficiency of shape coding is an important problem concerning content-based image manipulations and object-based coding of the video sequences. In order to encode the shape information of an object, the boundary is approximated by a polygon which can be encoded with the smallest number of bits for maximum allowable distortion. The conventional boundary coding schemes, however, does not successfully remove the temporal redundancy of the video sequences. This paper proposes a new boundary encoding scheme by which the temporal redundancy between two successive frames is efficiently removed, resulting in lower bit-rate than the conventional algorithms. The interframe vertex selection problem is solved by finding the path with the minimum cost in the directed acyclic graph (DAG) and its fast version using a simplified graph is introduced to reduce the computational load. The vertices were selected from both the current frame to be encoded and the previous frame already encoded, and thus, the temporal redundancy was effectively removed.

Adaptive approximation bounds for vertex based contour encoding

When approximating the shape of a region, a fixed bound on the tolerable distortion is set for approximating its contour points. An adaptive approximation bound for lossy coding of the contour points is proposed. A function representing the relative significance of the contour points is defined to adjust the distortion bound along the region contour allowing an adaptive approximation of the region shape. The effectiveness of the adaptive contour coding approach for a region-based coding system is verified through experiments.

Raf-1 kinase, a potential regulator of intracellular pH in Xenopus oocytes

Xenopus laevis oocytes undergo an increase in intracellular pH (pHi) from 7.2 to 7.7 due to the up-regulation of Na+/H+ antiporters in their plasma membrane during oocyte meiotic maturation. Up-regulation of Na+/H+ exchangers (NHE) found in other cell systems appears to be controlled, in some cases, by direct phosphorylation of the exchanger. A number of active protein kinases can be found in maturing Xenopus oocytes. These include, c-mos kinase, Raf-1 kinase, mitogen-activated kinase kinase (MAPKK), MAPK, ribosomal S6 kinase (RSK), and histone H-1 kinase. Our previous study indicated that c-mos kinase, was involved in regulating the increase in oocyte pHi. In the current study, we show that when mRNA coding for a constitutively active form of Raf-1 kinase (delta N-Raf-1) was microinjected into oocytes, the protein product induced an increase in oocyte pHi. On the contrary, the injection of mRNA coding for wild-type Raf-1 (WT-Raf-1) or a kinase-deficient form of Raf-1 (KD-Raf-1) had no effect on the recipient oocyte pHi. 8-Br-cAMP and forskolin blocked the increase in pHi during oocyte meiotic maturation, but had no effect on the Raf-1-induced increase in oocyte pHi. Studies using antisense c-mos oligos demonstrated that Raf-1 was not working via a feedback loop to endogenous c-mos mRNA within the recipient oocytes. Experiments using the selective MAPKK inhibitor, PD 98059, indicated that the Raf-1 effect on oocyte pHi was not mediated by the downstream kinase, MAPKK. Therefore, Raf-1 appears to act independently of c-mos kinase in a pathway, not involving MAPKK, leading to the up-regulation of the Na+/H+ antiporters in Xenopus oocytes.

A new mouse gene, SRG3, related to the SWI3 of Saccharomyces cerevisiae, is required for apoptosis induced by glucocorticoids in a thymoma cell line

We isolated a new mouse gene that is highly expressed in thymocytes, testis, and brain. This gene, SRG3, showed a significant sequence homology to SWI3, a yeast transcriptional activator, and its human homolog BAF155. SRG3 encodes 1,100 amino acids and has 33-47% identity with SWI3 protein over three regions. The SRG3 protein contains an acidic NH2 terminus, a myb-like DNA binding domain, a leucine-zipper motif, and a proline- and glutamine-rich region at its COOH terminus. Rabbit antiserum raised against a COOH-terminal polypeptide of the SRG3 recognized a protein with an apparent molecular mass of 155 kD. The serum also detected a 170-kD protein that seems to be a mouse homologue of human BAF170. Immunoprecipitation of cell extract with the antiserum against the mouse SRG3 also brought down a 195-kD protein that could be recognized by an antiserum raised against human SWI2 protein. The results suggest that the SRG3 protein associates with a mouse SWI2. The SRG3 protein is expressed about three times higher in thymocytes than in peripheral lymphocytes. The expression of anti-sense RNA to SRG3 mRNA in a thymoma cell line, S49.1, reduced the expression level of the SRG3 protein, and decreased the apoptotic cell death induced by glucocorticoids. These results suggest that the SRG3 protein is involved in the glucocorticoid-induced apoptosis in the thymoma cell line. This implicates that the SRG3 may play an important regulatory role during T cell development in thymus.

Simultaneous multichannel image restoration and estimation of the regularization parameters

In this correspondence, a constrained least-squares multichannel image restoration approach is proposed, in which no prior knowledge of the noise variance at each channel or the degree of smoothness of the original image is required. The regularization functional for each channel is determined by incorporating both within-channel and cross-channel information. It is shown that the proposed smoothing functional has a global minimizer.

General choice of the regularization functional in regularized image restoration

The determination of the regularization parameter is an important issue in regularized image restoration, since it controls the trade-off between fidelity to the data and smoothness of the solution. A number of approaches have been developed in determining this parameter. In this paper, a new paradigm is adopted, according to which the required prior information is extracted from the available data at the previous iteration step, i.e., the partially restored image at each step. We propose the use of a regularization functional instead of a constant regularization parameter. The properties such a regularization functional should satisfy are investigated, and two specific forms of it are proposed. An iterative algorithm is proposed for obtaining a restored image. The regularization functional is defined in terms of the restored image at each iteration step, therefore allowing for the simultaneous determination of its value and the restoration of the degraded image. Both proposed iteration adaptive regularization functionals are shown to result in a smoothing functional with a global minimum, so that its iterative optimization does not depend on the initial conditions. The convergence of the algorithm is established and experimental results are shown.