Regulation of human ß-galactoside α2,6-sialyltransferase (hST6Gal I) gene expression during differentiation of human osteoblastic MG-63 cells.

In this study, we found that gene expression of the human ß-galactoside α2,6-sialyltransferase (hST6Gal I) was specifically increased during differentiation of human MG-63 osteoblastic cells by serum starvation (SS). In parallel, a distinct increase in binding to SNA, the α2,6-sialyl-specific lectin, was observed in serum-starved cells, as demonstrated by FACS analysis. 5'-Rapid amplification of cDNA ends analysis demonstrated that the increase of hST6Gal I transcript by SS is mediated by P1 promoter. To elucidate transcriptional regulation of hST6Gal I in SS-induced MG-63 cells, we functionally characterized the P1 promoter region of the hST6Gal I gene. The 5'-deletion analysis of P1 promoter region revealed that the 189 bp upstream region of transcription start site is critical for transcriptional activity of hST6Gal I gene in SS-induced MG-63 cells. This region contains the predicted binding sites for several transcription factors, including AREB6, FOXP1, SIX3, HNF1, YY2, and MOK2. The mutagenesis analysis for these sites and chromatin immunoprecipitation assay demonstrated that the YY2 binding site at -98 to -77 was essential for the SS-induced hST6Gal I gene expression during differentiation of MG-63 cells.

4-O-carboxymethylascochlorin protected against microglial-mediated neurotoxicity in SH-SY5Y and BV2 cocultured cells from LPS-induced neuroinflammation and death by inhibiting MAPK, NF-κB, and Akt pathways.

In our previous studies, structurally similar compounds of ascochlorin and ascofuranone exhibited anti-inflammatory activity. Neural inflammation plays a significant role in the commence and advancement of neurodegenerative diseases. It is not known whether 4-O-carboxymethylascochlorin (AS-6) regulates the initial stage of inflammatory responses at the cellular level in BV2 microglia cells. We here investigated the anti-inflammatory effects of AS-6 treatment in microglia cells with the microglial protection in neurons. We found that the lipopolysaccharide (LPS)-stimulated production of nitric oxide, a main regulator of inflammation, is suppressed by AS-6 in BV2 microglial cells. In addition, AS-6 dose-dependently suppressed the increase in COX-2 protein and messenger RNA levels in LPS-stimulated BV2 cells. Moreover, AS-6 inhibited the expression and secretion of proinflammatory cytokines in BV2 microglial cells. At the intracellular level, AS-6 inhibited LPS-activated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in BV2 microglial cells. AS-6 negatively affected mitogen-activated protein kinases (MAPK) and Akt phosphorylation: Phosphorylated forms of ERK, JNK, p38, and Akt decreased. To check whether AS-6 protects against inflammatory inducer-mediated neurotoxicity, neuronal SH-SY5Y cells were coincubated with BV2 cells in conditioned medium. AS-6 exerted a neuroprotective effect by suppressing microglial activation by LPS or amyloid-ß peptide. AS-6 is a promising suppressor of inflammatory responses in LPS-induced BV2 cells by attenuating NF-κB and MAPKs signaling. AS-6 protected against microglial-mediated neurotoxicity in SH-SY5Y and BV2 cocultured cells from LPS-induced neuroinflammation and death via inhibiting MAPK, NF-κB, and Akt pathways.

Transcriptional Activation of Human GD3 Synthase (hST8Sia I) Gene in Curcumin-Induced Autophagy in A549 Human Lung Carcinoma Cells.

Curcumin, a natural polyphenolic compound isolated from the plant Curcuma longa, is known to induce autophagy in various cancer cells, including lung cancer. In the present study, we also confirmed by LC3 immunofluorescence and immunoblotting analyses that curcumin triggers autophagy in the human lung adenocarcinoma A549 cell line. In parallel with autophagy induction, the gene expression of human GD3 synthase (hST8Sia I) responsible for ganglioside GD3 synthesis was markedly elevated in response to curcumin in the A549 cells. To investigate the transcriptional activation of hST8Sia I associated with the autophagy formation in curcumin-treated A549 cells, functional characterization of the 5'-flanking region of the hST8Sia I gene was carried out using the luciferase reporter assay system. Deletion analysis demonstrated that the -1146 to -646 region, which includes the putative c-Ets-1, CREB, AP-1, and NF-κB binding sites, functions as the curcumin-responsive promoter of hST8Sia I in A549 cells. The site-directed mutagenesis and chromatin immunoprecipitation assay demonstrated that the NF-κB binding site at -731 to -722 was indispensable for the curcumin-induced hST8Sia I gene expression in A549 cells. Moreover, the transcriptional activation of hST8Sia I by the curcumin A549 cells was strongly inhibited by compound C, an inhibitor of AMP-activated protein kinase (AMPK). These results suggest that curcumin controls hST8Sia I gene expression via AMPK signal pathway in A549 cells.

Identification of cornifelin and early growth response-1 gene as novel biomarkers for in vitro eye irritation using a 3D reconstructed human cornea model MCTT HCE™.

Evaluation of the eye irritation is essential in the development of new cosmetic products. Draize rabbit eye irritation test has been widely used in which chemicals are directly applied to rabbit eye, and the symptoms and signs of eyes are scored. However, due to the invasive procedure, it causes substantial pain and discomfort to animals. Recently, we reported in vitro eye irritation test method using a 3D human corneal epithelial model (MCTT HCE™) which is reconstructed from remaining human tissues after a corneal transplantation. This model exhibited an excellent predictive capacity for 25 reference chemicals (sensitivity 100%, specificity 77% and accuracy 88% vs. GHS). To improve the test performance, we explored new biomarkers for the eye irritation through transcriptomic approach. Three surfactants were selected as model eye irritants that include sodium lauryl sulfate, benzalkonium chloride and triton X-100. After test chemicals were treated, we investigated differentially expressed genes through a whole-gene microarray (Affymetrix GeneChip(®) Human Gene 2.0 ST Array, 48,000 probes). As a result, we identified that mRNAs of cornifelin (CNFN), a constituent of the insoluble cornified cell envelope of stratified squamous epithelia, and early growth response-1 (EGR1), a nuclear transcriptional regulator, were significantly up-regulated by all three irritants. Up-regulation of CNFN and EGR1 was further confirmed by Q-RT-PCR, and immunohistochemistry revealed increased level of CNFN in irritant-treated tissues, supporting the relevance of CNFN and EGR1 as new biomarkers for eye irritation.

Remaining life expectancy of Korean hemodialysis patients: how much longer can they live?

Background: Hemodialysis (HD) patients have a higher mortality rate compared to the general population. However, no study has investigated life expectancy in Korean HD patients so far. Therefore, this study aimed to calculate the remaining life expectancy among Korean maintenance HD patients and compare it to those of the general population as well as HD patients from other countries. Methods: Baseline data were retrieved from HD quality assessment data from 2015. Among the patients over 30 years old who were alive at the beginning of 2016 (20,304 males and 14,264 females), a total of 22,078 (12,621 males and 9,457 females) were still alive at the end of 2021 while 12,490 (7,683 males and 4,807 females) were deceased during 6 years of follow-up. We used the life table method to calculate the expected remaining years of life in 2-year increments. Results: The remaining life expectancies for 60-year-old patients were 11.64 years for males and 14.64 years for females. The average remaining lifetimes of the HD population were only about half of the general population. Diabetic patients demonstrated shorter life expectancy compared to patients with hypertension or glomerulonephritis. The remaining life expectancy of Korean HD patients was similar to that of Japanese and was almost double that of HD patients in Western countries such as Europe and the United States. Conclusion: The HD population shows shorter life expectancy compared to the general population. Longitudinal analysis should be warranted to analyze the effect of advanced dialysis technology on improved survival rates among the HD population.

Temperature-dependent thermal conductivities of 1D semiconducting nanowires via four-point-probe 3-ω method.

We report on a systematic study of the thermal transport characteristics of both as-grown zinc oxide and gallium nitride nanowires (NWs) via the four-point-probe 3-ω method in the temperature range 130-300 K. Both as-grown NWs were synthesized by a vapor-liquid-solid growth mechanism, and show clear n-type semiconducting behavior without any defects, which enables both the NWs to be promising candidates for thermoelectric materials. To measure the thermal conductivities of both NWs with lower heat loss and measurement errors, the suspended structures were formed by a combination of an e-beam lithography process and a random dispersion method. The measured thermal conductivities of both NWs are greatly reduced compared to their bulk materials due to the enhanced phonon scattering via the size effect and dopants (impurities). Furthermore, we observed that the Umklapp peaks of both NWs are shifted to a higher temperature than those of their bulk counterparts, indicating that phonon-boundary scattering dominates over other phonon scattering due to the size effect.

Thermal conductivity measurements of single-crystalline bismuth nanowires by the four-point-probe 3-ω technique at low temperatures.

We have successfully investigated the thermal conductivity (κ) of single-crystalline bismuth nanowires (BiNWs) with [110] growth direction, via a straightforward and powerful four-point-probe 3-ω technique in the temperature range 10-280 K. The BiNWs, which are well known as the most effective material for thermoelectric (TE) device applications, were synthesized by compressive thermal stress on a SiO2/Si substrate at 250-270 °C for 10 h. To understand the thermal transport mechanism of BiNWs, we present three kinds of experimental technique as follows, (i) a manipulation of a single BiNW by an Omni-probe in a focused ion beam (FIB), (ii) a suspended bridge structure integrating a four-point-probe chip by micro-fabrication to minimize the thermal loss to the substrate, and (iii) a simple 3-ω technique system setup. We found that the thermal transport of BiNWs is highly affected by boundary scattering of both phonons and electrons as the dominant heat carriers. The thermal conductivity of a single BiNW (d ~ 123 nm) was estimated to be ~2.9 W m(-1) K(-1) at 280 K, implying lower values compared to the thermal conductivity of the bulk (~11 W m(-1) K(-1) at 280 K). It was noted that this reduction in the thermal conductivity of the BiNWs could be due to strongly enhanced phonon-boundary scattering at the surface of the BiNWs. Furthermore, we present temperature-dependent (10-280 K) thermal conductivity of the BiNWs using the 3-ω technique.

The Geriatric Nutritional Risk Index Is an Optimal Evaluation Parameter for Predicting Mortality in Adult All Ages Hemodialysis Patients: A Korean Population-Based Study.

The Geriatric Nutritional Risk Index (GNRI) is a nutritional screening tool used for predicting mortality in patients undergoing hemodialysis (HD). This study investigated the cutoff values for the GNRI for predicting mortality in HD patients using Korean HD quality assessment data from 2015. To identify the optimal GNRI cutoff value, we used Harrell's C-index with multivariate Cox regression models. The highest value of C-index was identified as the cutoff value of GNRI for all-cause mortality in this population. In total, 34,933 patients were included; 90.8 of GNRI was the highest value of C-index, and it was used as a cutoff value to predict mortality; 3311 patients (9.5%) had GNRI values < 90.8, and there were 12,499 deaths during the study period. The mean follow-up period was 53.7 months. The crude mortality rates in patients with GNRI values < 90.8 and ≥ 90.8 were 160.4/1000 and 73.2/1000 person-years respectively. In the fully adjusted Cox model, patients with a GNRI < 90.8 had a 1.78 times higher risk of mortality than those with a GNRI ≥ 90.8. These findings suggest that the optimal GNRI cutoff value is 90.8 for predicting mortality in maintenance HD patients.

Regular laboratory testing and patient survival among patients undergoing maintenance hemodialysis: a Korean nationwide cohort study.

Routine laboratory tests are regularly performed in patients undergoing maintenance hemodialysis (HD) to detect anemia, chronic kidney disease-mineral bone disorders, and cardiovascular disease. More frequent laboratory tests may be associated with better outcomes. However, there is little evidence supporting a specific monitoring interval. This study evaluated the impact of regular laboratory testing on mortality in Korean patients undergoing maintenance HD. We used HD quality assessments, and National Health Insurance Service claims data from October to December 2015. In HD quality assessment, 22 tests are recommended every 1-6 months. A total of 34,950 patients were divided into two groups based on the regularity of laboratory testing. A Cox proportional hazards model was used to assess the effects of regular laboratory tests on patient mortality during a mean follow-up duration of 53.7 months. The proportion of patients with and without regular laboratory testing was 85.6% (n = 29,914) and 14.4% (n = 5036), respectively. Patients who underwent regular laboratory testing had a longer dialysis duration, lower serum phosphorus levels and diastolic blood pressure, and higher hemoglobin and single-pool Kt/V levels than those who did not. After adjusting for demographic and clinical parameters, regular laboratory testing independently reduced mortality risk (hazard ratio, 0.90; 95% confidence interval 0.85-0.95; P < 0.001). Regular laboratory testing was associated with a decreased mortality risk among patients undergoing HD. Management of end-stage kidney disease-related complications based on laboratory tests can improve survival.

Application of an endo-GIA for ligation of the cystic duct during difficult laparoscopic cholecystectomy.

BACKGROUND/AIMS: Laparoscopic cholecystectomy has become the gold standard modality for treating gallbladder disease. There are many techniques for the ligation of a dilated and inflamed cystic duct. The aim of this study is to assess the efficacy and applicability of an Endo-GIA for dilated cystic duct ligation. METHODOLOGY: From October 1992 to September 2009, 3413 patients underwent laparoscopic cholecystectomy for gallbladder disease at the Dong-A Medical Center, and 92 (2.7%) patients' cystic ducts were ligated by an Endo-GIA. We retrospectively analyzed these 92 cases. RESULTS: The cystic ducts were successfully ligated with an Endo-GIA in 88 patients. Four patients required conversion to open surgery. The mean operation time was 111.9 minutes. The mean length of the hospital stay was 4.1 days. Postoperative complication occurred in 16 patients (17%). The follow-up period ranged from 0.5 to 75 months. CONCLUSIONS: Endo-GIA is safe and feasible. Postoperative complication occurred in 16 patients after application of an Endo-GIA. However, those complications were successfully managed by conservative treatment. The rate of complications was comparable to the best results from most of the large series in the West. Therefore, using an Endo-GIA could be attempted in carefully selected patients with difficult cases of laparoscopic cholecystectomy.

Clinical outcomes and breast cancer subtypes in patients with brain metastases.

BACKGROUND: The principal objective of this study was to assess clinical outcomes by breast cancer subtype in patients with brain metastases. METHODS: Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) status was evaluated via immunohistochemical staining. Four survival time intervals were compared according to the subtype (ER+/HER2-, HER2+, triple negative (TN)). RESULTS: 20 (30.3%) of the 66 patients in this study were ER+/HER2-, 20 (30.3%) were HER2+, and 26 (39.4%) were TN. The disease-free survival rates of ER+/HER2-, HER2+, and TN patients were 30.0, 17.0, and 17.9 months, respectively (p = 0.040). The median time intervals from distant metastasis to brain metastasis were 20.6, 19.5, and 9.0 months, respectively (p = 0.012). The times from initial diagnosis to brain metastasis were 52.9, 33.6, and 25.5 months, respectively (p = 0.026). However, the overall survival rates did not differ significantly (p = 0.276). CONCLUSIONS: Patients with TN breast cancer were more likely to develop distant metastasis earlier, and also evidenced poor overall survival. Triple receptor status may be employed as a prognostic marker for breast cancer patients with brain metastases.

An optimised method for the rapid analysis of condensed phosphates in fishery and processed marine food products using ion chromatography and microwave sample processing.

Condensed phosphates are deliberately added to the fishery and processed marine food products on purpose to increase the weight of products. However, excessive intake overwhelming bodily homoeostasis can result in phosphate toxicity such as mineral and bone disorders, associated with chronic kidney diseases, and cardiovascular events. Rapid analysis for condensed phosphates is required to detect the illegal adulteration of processed marine products. We optimised an analytical method using ion chromatography for the rapid and selective detection of condensed phosphates in various kinds of fishery and processed marine products. We compared the performance of three columns (IonPac AS11, AS11-HC, and AS16) for the detection of condensed phosphates with respect to time of analysis and sensitivity. The IonPac AS11 column exhibited the shortest retention time for the major condensed phosphates (pyro-, tri-, and trimetaphosphate), the highest sensitivity for trimetaphosphate, and good repeatability and precision. Microwave and boiling processing were examined as methods to prevent hydrolysis of condensed phosphates into orthophosphate, which is critical in distinguishing intentionally added condensed phosphates from naturally occurring orthophosphate. Microwave treatment was determined to be the more effective method to suppress hydrolysis of condensed phosphates to orthophosphate. Furthermore, microwave processing could be used for thawing the frozen samples, saving extra effort and time. We confirmed that the method exhibits good recovery (80% or more) and precision (%RSD < 10%) for samples with various matrices. With the method, 14 kinds of fishery and processed marine food products were successfully analysed for condensed phosphates. Especially, we identified that phosphate levels in the processed shrimp and dried shredded squid samples exceeded the maximum allowable levels specified in the CODEX standard. We believe that our method would be useful for the rapid analysis of condensed phosphates in various types of fishery and processed marine food products.

Development and validation of UPLC method for WST-1 cell viability assay and its application to MCTT HCE™ eye irritation test for colorful substances.

WST-1 [Water Soluble Tetrazolium-1; 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt)] is widely used in the cell viability assays replacing MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). A water-soluble formazan dye (4-[1-(4-Iodophenyl)-5-(4-nitrophenyl)formaz-3-yl]-1,3-benzene disulfonate, disodium salt) is produced from the reduction of WST-1 tetrazolium, of which optical density at 450 nm is measured to evaluate cell viability. Colorful substances may interfere with spectrometric measurement, and a method to specifically detect WST-1 formazan is required. Here, a simple, rapid, sensitive, and specific ultra-performance liquid chromatography coupled to UV detector (UPLC-UV) was developed and validated for the WST-1 formazan. For the application to cell viability assay, the supernatant from WST-1 assay was injected without sample preparation procedure and a single run was completed within 5 min. Chromatographic separation was achieved on BEH C18 column (1.7 µm, 2.1 × 50 mm) using gradient elution with the mobile phase of water and acetonitrile. The standard curves were linear over the concentration range of 2.5-120 µg/mL WST-1 formazan, which encompasses WST-1 formazan concentrations from 2% cell viability to 2 fold of 100% cell viability. The intra- and inter-day precisions were measured to be below 5% and accuracies were within the range of 91.8-104.9%. The validated method was successfully applied to the test of colorful substances in vitro eye irritation test with a human cornea-like epithelium, and in vitro cytotoxicity in HaCaT, human keratinocyte cell line.

Curcumin Downregulates Human GM3 Synthase (hST3Gal V) Gene Expression with Autophagy Induction in Human Colon Carcinoma HCT116 Cells.

Our recent report showed that curcumin, polyphenolic compound isolated from the herb Curcuma longa, upregulated the gene expression of human GD3 synthase (hST8Sia I) responsible for ganglioside GD3 synthesis with autophagy induction in human lung adenocarcinoma A549 cells. In this study, on the contrary to this finding, we demonstrated that curcumin downregulated the gene expression of human GM3 synthase (hST3Gal V) catalyzing ganglioside GM3 synthesis with autophagy induction in human colon carcinoma HCT116 cells. To clarify the mechanism leading to the downregulation of hST3Gal V gene expression in curcumin-treated HCT116 cells, we analyzed the curcumin-inducible promoter of the hST3Gal V gene by luciferase reporter assays. Promoter deletion analysis demonstrated that the -177 to -83 region, which includes putative binding sites for transcription factors NFY, CREB/ATF, SP1, EGR3, and MZF1, acts as the curcumin-responsive promoter of the hST3Gal V gene. Site-directed mutagenesis and chromatin immunoprecipitation analysis demonstrated that the CREB/ATF binding site at -143 is pivotal for curcumin-induced downregulation of hST3Gal V gene in HCT116 cells. The transcriptional activation of hST3Gal V in HCT116 cells was significantly repressed by an inhibitor of AMP-activated protein kinase (AMPK). These results suggest that AMPK signal pathway mediates hST3Gal V gene expression in HCT116 cells.

Nervonoylceramide (C24:1Cer), a lipid biomarker for ocular irritants released from the 3D reconstructed human cornea-like epithelium, MCTT HCE™.

Due to invasive and painful procedures during in vivo rabbit eye irritation test, in vitro alternative methods have been widely investigated. Recently, 3D reconstructed human cornea-like epitheliums (RhCEs) garner a huge attention. RhCEs employ the tissue viability as a primary endpoint to determine ocular irritancy but additional biomarkers may improve its predictive capacity. Here, we explored lipid biomarkers for ocular irritants in MCTT HCE™ RhCE model. Three irritants; sodium lauryl sulfate, benzalkonium chloride and triton X-100 were selected to represent anionic, cationic and non-ionic detergent respectively. After treating MCTT HCE™ with irritants, the alteration of lipids in the treated tissues was examined with Nile Red staining, which revealed the depletion of corneal lipids. We further quantitated the release of ceramides and free fatty acids, major lipid components of cornea, into the medium during the post-treatment incubation, employing a sensitive UPLC-MS/MS method. Among 44 lipid species, nervonoylceramide (C24:1Cer) was found to be released commonly by all three irritants in a concentration-dependent manner. Tests with 10 additional reference substances further supported that C24:1Cer release was significantly correlated with viability. Examination of the genes involved in the biosynthetic pathway for C24:1Cer revealed that stearoylCoA desaturase (SCD) and elongase1 (ELOVL1) were upregulated, suggesting that lipids and related genes may be employed as biomarkers for ocular irritants.

Alternatives to In Vivo Draize Rabbit Eye and Skin Irritation Tests with a Focus on 3D Reconstructed Human Cornea-Like Epithelium and Epidermis Models.

Human eyes and skin are frequently exposed to chemicals accidentally or on purpose due to their external location. Therefore, chemicals are required to undergo the evaluation of the ocular and dermal irritancy for their safe handling and use before release into the market. Draize rabbit eye and skin irritation test developed in 1944, has been a gold standard test which was enlisted as OECD TG 404 and OECD TG 405 but it has been criticized with respect to animal welfare due to invasive and cruel procedure. To replace it, diverse alternatives have been developed: (i) For Draize eye irritation test, organotypic assay, in vitro cytotoxicity-based method, in chemico tests, in silico prediction model, and 3D reconstructed human cornea-like epithelium (RhCE); (ii) For Draize skin irritation test, in vitro cytotoxicity-based cell model, and 3D reconstructed human epidermis models (RhE). Of these, RhCE and RhE models are getting spotlight as a promising alternative with a wide applicability domain covering cosmetics and personal care products. In this review, we overviewed the current alternatives to Draize test with a focus on 3D human epithelium models to provide an insight into advancing and widening their utility.

Evaluation of ocular irritancy of coal-tar dyes used in cosmetics employing reconstructed human cornea-like epithelium and short time exposure tests.

Coal-tar dyes in cosmetics may elicit adverse effects in the skin and eyes. Countries, like the US, have banned the use of coal-tar dyes in cosmetics for the eye area due to the potential for ocular irritation. We evaluated the eye irritation potential of 15 coal-tar dyes permitted as cosmetic ingredients in reconstructed human cornea-like epithelium (RhCEs [EpiOcular™ and MCTT HCE™]) tests and the short time exposure (STE) test. Eosin YS, phloxine B, tetrachlorotetrabromofluorescein, and tetrabromofluorescein were identified as irritants in RhCEs; dibromofluorescein and uranine yielded discrepant results. STE enabled further classification in accordance with the UN Globally Harmonized System of Classification and Labelling of Chemicals, as follows: eosin YS as Cat 2; phloxine B, Cat 1; and tetrachlorotetrabromofluorescein and tetrabromofluorescein, Cat 1/2. STE indicated dibromofluorescein (irritant in EpiOcular™) and uranine (irritant in MCTT HCE™) as No Cat, resulting in the classification of "No prediction can be made." based on bottom-up approach with each model. These results demonstrated that in vitro eye irritation tests can be utilized to evaluate the potential ocular irritancy of cosmetic ingredients and provide significant evidence with which to determine whether precautions should be given for the use of coal-tar dyes in cosmetics or other substances applied to the eye area.

Rhododenol and raspberry ketone impair the normal proliferation of melanocytes through reactive oxygen species-dependent activation of GADD45.

Rhododenol or rhododendrol (RD, 4-(4-hydroxyphenyl)-2-butanol) occurs naturally in many plants along with raspberry ketone (RK, 4-(4-hydroxyphenyl)-2-butanone), a ketone derivative, which include Nikko maple tree (Acer nikoense) and white birch (Betula platyphylla). De-pigmenting activity of RD was discovered and it was used as a brightening ingredient for the skin whitening cosmetics. Recently, cosmetics containing RD were withdrawn from the market because a number of consumers developed leukoderma, inflammation and erythema on their face, neck and hands. Here, we explored the mechanism underlying the toxicity of RD and RK against melanocytes using B16F10 murine melanoma cells and human primary epidermal melanocytes. Treatment with RD or RK resulted in the decreased cell viability in a dose-dependent manner which appeared from cell growth arrest. Consistently, ROS generation was significantly increased by RD or RK as determined by DCF-enhanced fluorescence. An antioxidant enzyme, glutathione peroxidase was depleted as well. In line with ROS generation, oxidative damages and the arrest of normal cell proliferation, GADD genes (Growth Arrest and DNA Damage) that include GADD45 and GADD153, were significantly up-regulated. Prevention of ROS generation with an anti-oxidant, N-acetylcysteine (NAC) significantly rescued RD and RK-suppressed melanocyte proliferation. Consistently, up-regulation of GADD45 and GADD153 was significantly attenuated by NAC, suggesting that increased ROS and the resultant growth arrest of melanocytes may contribute to RD and RK-induced leukoderma.

Exploration and comparison of in vitro eye irritation tests with the ISO standard in vivo rabbit test for the evaluation of the ocular irritancy of contact lenses.

In an effort to explore the use of alternative methods to animal testing for the evaluation of the ocular irritancy of medical devices, we evaluated representative contact lenses with the bovine corneal opacity and permeability test (BCOP) and an in vitro eye irritation test using the three-dimensionally-reconstructed human corneal epithelium (RhCE) models, EpiOcular™ and MCTT HCE™. In addition, we compared the obtained results with the ISO standard in vivo rabbit eye irritation test (ISO10993-10). Along with the positive controls (benzalkonium chloride, BAK, 0.02, 0.2, and 1%), the extracts of 4 representative contact lenses (soft, disposable, hard, and colored lenses) and 2 reference lenses (dye-eluting and BAK-coated lenses) were tested. All the lenses, except for the BAK-coated lens, were determined non-irritants in all test methods, while the positive controls yielded relevant results. More importantly, BCOP, EpiOcular™, and MCTT HCE™ yielded a consistent decision for all the tested samples, with the exception of 0.2% BAK in BCOP, for which no prediction could be made. Overall, all the in vitro tests correlated well with the in vivo rabbit eye irritation test, and furthermore, the combination of in vitro tests as a tiered testing strategy was able to produce results similar to those seen in vivo. These observations suggest that such methods can be used as alternative assays to replace the conventional in vivo test method in the evaluation of the ocular irritancy of ophthalmic medical devices, although further study is necessary.

Novel anti-melanogenic hexapeptoids, PAL-10 and PAL-12.

Diverse compound sources are being explored for de-pigmentation activities to develop novel therapeutic agents or functional cosmetic ingredients for hyper-pigmentation disorders. Peptoids are a class of peptidomimetics whose side chains are appended to the nitrogen atom of the peptide backbone, instead of α-carbon. Peptoids are more durable against proteolysis and are being actively investigated in drug discovery, but rarely studied as cosmetic ingredients. Here, we demonstrated that new hexa-peptoids, PAL-10 and PAL-12, can inhibit melanogenesis in B16F10 melanoma cells, a 3D pigmented human skin model (Neoderm(®)-ME, Tegoscience Co) and zebrafish. Anti-melanogenic effects of PAL-10 or PAL-12 as compared with arbutin, a positive control in B16F10 cells, Neoderm(®)-ME and zebrafish were statistically significant and concentration-dependent anti-melanogenic effects were manifested as determined by image, histology, and melanin contents. Anti-melanogenic effects of PAL-10 appeared to be from enzymatic inhibition of tyrosinase while mRNA expression of melanogenic enzymes was not affected. In conclusion, we demonstrated that PAL-10 and PAL-12 can be used as a new cosmetic ingredient with strong brightening efficacies.