The DNA methylation inhibitor 5-azacytidine decreases melanin synthesis by inhibiting CREB phosphorylation.

Here we examined the effects of a DNA methylation inhibitor, 5-azacytidine, on melanogenesis in Mel-Ab cells. We found that 5-azacytidine decreased the melanin content and tyrosinase activity in these cells in a dose-dependent manner; importantly, 5-azacytidine was not cytotoxic at the concentrations used in these experiments. On the other hand, 5-azacytidine did not affect tyrosinase activity in a cell-free system, indicating that 5-azacytidine is not a direct tyrosinase inhibitor. Instead, 5-azacytidine decreased the protein levels of microphthalmia-associated transcription factor (MITF) and tyrosinase. Thus, we investigated the effects of 5-azacytidine on signal transduction pathways related to melanogenesis. However, 5-azacytidine did not have any effect on either Akt or glycogen synthase kinase 3ß (GSK3ß) phosphorylation. The phosphorylation of cAMP response element-binding protein (CREB) is well known to regulate MITF expression, thereby also regulating tyrosinase expression. We found that 5-azacytidine decreased the phosphorylation of CREB. Therefore, we propose that 5-azacytidine may decrease melanin synthesis by downregulating MITF and tyrosinase via CREB inactivation.

ERK Activation by Fucoidan Leads to Inhibition of Melanogenesis in Mel-Ab Cells.

Fucoidan, a fucose-rich sulfated polysaccharide derived from brown seaweed in the class Phaeophyceae, has been widely studied for its possible health benefits. However, the potential of fucoidan as a possible treatment for hyperpigmentation is not fully understood. This study investigated the effects of fucoidan on melanogenesis and related signaling pathways using Mel-Ab cells. Fucoidan significantly decreased melanin content. While fucoidan treatment decreased tyrosinase activity, it did not do so directly. Western blot analysis indicated that fucoidan downregulated microphthalmia-associated transcription factor and reduced tyrosinase protein expression. Further investigation showed that fucoidan activated the extracellular signal-regulated kinase (ERK) pathway, suggesting a possible mechanism for the inhibition of melanin synthesis. Treatment with PD98059, a specific ERK inhibitor, resulted in the recovery of melanin production. Taken together, these findings suggest that fucoidan inhibits melanogenesis via ERK phosphorylation.

Scopoletin from Cirsium setidens Increases Melanin Synthesis via CREB Phosphorylation in B16F10 Cells.

In this study, we isolated scopoletin from Cirsium setidens Nakai (Compositae) and tested its effects on melanogenesis. Scopoletin was not toxic to cells at concentrations less than 50 µM and increased melanin synthesis in a dose-dependent manner. As melanin synthesis increased, scopoletin stimulated the total tyrosinase activity, the rate-limiting enzyme of melanogenesis. In a cell-free system, however, scopoletin did not increase tyrosinase activity, indicating that scopoletin is not a direct activator of tyrosinase. Furthermore, Western blot analysis showed that scopoletin stimulated the production of microphthalmia-associated transcription factor (MITF) and tyrosinase expression via cAMP response element-binding protein (CREB) phosphorylation in a dose-dependent manner. Based on these results, preclinical and clinical studies are needed to assess the use of scopoletin for the treatment of vitiligo.

Leucine-rich glioma inactivated 3 promotes HaCaT keratinocyte migration.

Our finding that human skin expresses leucine-rich glioma inactivated 3 (LGI3) raises the question of the function of this cytokine in keratinocytes. We have shown that LGI3 stimulates human HaCaT keratinocyte migration without affecting viability or proliferation. Western blot analysis showed that LGI3 induced focal adhesion kinase activation, Akt phosphorylation, and glycogen synthase kinase 3ß (GSK3ß) phosphorylation in these cells. Using the scratch wound assay and a modified Boyden chamber, we found that LY294002, a selective phosphatidylinositol 3-kinase inhibitor, and LiCl, a selective GSK3ß inhibitor, abolished LGI3-induced cell migration. We tested ß-catenin levels after LGI3 treatment because the Akt-GSK3ß pathway regulates ß-catenin accumulation, and ß-catenin promotes cell migration. LGI3 treatment increased ß-catenin protein and nuclear localization, whereas LY294002 prevented LGI3-induced focal adhesion kinase and Akt activation as well as ß-catenin accumulation. Overall, these data suggest that LGI3 stimulates HaCaT cell migration following ß-catenin accumulation through the Akt pathway.

The effects of pigs' feet consumption on lactation.

Pigs' feet are traditionally consumed by Korean women to increase milk production during lactation. In this study, we evaluated the perceived effectiveness and safety of consuming pigs' feet. Parous women were recruited to complete survey questionnaires in South Korea. Of the 516 respondents, 188 (36%) claimed they consumed pigs' feet. One-hundred twenty women (64%) who consumed pigs' feet reported experiencing an increase in breast milk production. Seventy-three (61%) women from this same group exclusively breastfed. In contrast, 16 (25%) of 65 respondents who did not embrace the same purported effect of pigs' feet indicated that they solely breastfed. Ninety-eight (82%) respondents who consumed pigs' feet and reported galactagoguic effects would recommend its use. Study findings reveal that the majority of women who consume pigs' feet believe in its milk-promoting effects. The results of this study suggest that further investigation of the galactagoguic effects of pigs' feet via conduction of an experimental study is warranted.

Impacts of a COVID-19 Educational Video: Evaluation of the Influence of Race, Gender, Political Affiliation, Study Major, and Age on Vaccine Acceptance among University Students.

BACKGROUND: The World Health Organization (WHO) warns that vaccine hesitancy is an ongoing major global health threat. While vaccination against severe acute respiratory syndrome coronavirus (SARS-CoV-2) proves to be an effective strategy in protecting against the disease, vaccine hesitancy represents a major barrier to stopping the spread of the virus. Willingness for vaccination can be influenced by several factors, including education level and health literacy. Although several studies demonstrate the value of video educational programs in improving coronavirus disease 2019 (COVID-19) vaccine knowledge and acceptance, no studies to date have evaluated if race, gender, and other demographic factors impact the influence of an educational video on COVID-19 vaccine knowledge and hesitancy among university students in the United States (U.S.). AIMS: This study was conducted to determine the impact of an educational video on U.S. university undergraduate students' COVID-19 vaccine perception and acceptance. It also aims to evaluate whether demographic factors affect the influence of the video. METHODS: An online survey was used to measure perceived understanding and acceptance of COVID-19 vaccines before and after viewing a video regarding the effectiveness and safety of COVID-19 vaccinations. The impact of demographic factors on the Video Influence Score was analyzed. KEY RESULTS: After viewing the video, respondents' (n = 285) perceived awareness and acceptance of COVID-19 vaccines significantly increased (p < 0.05). In addition, gender, political party affiliation, age, study major, and influenza vaccination history did not significantly impact the Video Influence Score (p > 0.05). However, African American/Black respondents (3.81 ± 4.24) were significantly more influenced by the video compared to respondents of other races (p < 0.05), such as White/Caucasian (1.91 ± 3.75), Hispanic/Latino (0.17 ± 3.67), Asian (0.29 ± 1.53), and Indigenous American (0.64 ± 2.52). CONCLUSIONS: This study suggests the potential impact of an educational video on COVID-19 vaccine perception and acceptance among university students. Despite limitations such as a modest survey response rate, this study provides valuable insight concerning the influential factors affecting vaccine acceptance in diverse student populations. Future studies are warranted to explore how student response to vaccine educational videos may vary depending on students' racial and cultural backgrounds. IMPLICATIONS: A targeted educational video to promote vaccine acceptance is a valuable tool for public health campaigns to combat vaccine hesitancy. The study also highlights the importance of tailoring interventions to specific demographic groups such as considering racial factors to maximize the impact of educational interventions on vaccine attitudes.

Evaluation of Enterococcal Probiotic Usage and Review of Potential Health Benefits, Safety, and Risk of Antibiotic-Resistant Strain Emergence.

Enterococci are often used in probiotics but can also cause nosocomial infections. As such, enterococcal consumption may have beneficial health effects, but a thorough evaluation of virulence absence and risk of antibiotic resistance spread is needed at the strain level. This article reviewed ten online health product shopping websites in the US. On these websites, 23 probiotic products using enterococci were found across 12 companies. In addition, this article reviewed studies that demonstrated the probiotic potential of enterococcal consumption (e.g., gastrointestinal and respiratory disease, hyperlipidemia alleviation, as well as infection prevention). To investigate the safety aspects of enterococci, the present work examined studies evaluating virulence factors and antibiotic resistance. Furthermore, this article assessed research that explored these virulent factors, specifically in probiotics containing enterococci, as well as the potential transfer mechanism of their antibiotic resistance. Based on reviewed data, enterococcal probiotic consumption has been proven beneficial for conditions or symptoms of multiple diseases without any apparent adverse effects. However, due to the plasmid- or transposon-mediated gene transfer ability of enterococci, surveillance monitoring and further studies regarding enterococcal consumption are warranted. Future studies that identify enterococcal strains safe to use in probiotics without virulence factors and antibiotic resistance are imperative for evidence-based decisions by health organizations and government agencies.

Arbutin inhibits TCCSUP human bladder cancer cell proliferation via up-regulation of p21.

Arbutin is a glycosylated hydroquinone extracted from the bearberry plant (Arctostaphylos species). In the present study, we determined the effects of arbutin on TCCSUP human bladder carcinoma cell proliferation. Arbutin did not exhibit any cytotoxic effects in TCCSUP cells at concentrations of < 500 microg/ml. To determine the effects of arbutin on cell proliferation, TCCSUP cells were treated with arbutin at various concentrations, and the cell proliferation was measured using the MTT assay. Arbutin significantly decreased TCCSUP cell proliferation in a concentration- and time-dependent manner. Furthermore, cell cycle analysis revealed that arbutin strongly disrupted the cell cycle in a time-dependent manner. Western blot analysis demonstrated that arbutin led to the inactivation of extracellular signal-regulated kinase (ERK), which is known to critically regulate cell proliferation. In addition, arbutin markedly increased the expression of p21WAF1/CIP1 (p21), which is known to be highly involved in cell cycle regulation. Therefore, this study suggests that arbutin inhibits TCCSUP cell proliferation via ERK inactivation and p21 up-regulation.

Use of maximum-dose simvastatin or atorvastatin in an ethnically diverse population.

PURPOSE: The use of maximum-dose simvastatin or atorvastatin in an ethnically diverse population was studied. METHODS: This retrospective analysis was conducted at a publicly funded teaching institution whose predominant patient population consists of Hispanics and Asians. A computer-generated report was used to identify outpatients who received a prescription for maximum-dose simvastatin or atorvastatin between January 1, 2002, and January 1, 2004. Data evaluated included demographic information; metabolic syndrome elements; coronary heart disease (CHD) risk equivalents; clinical characteristics placing patients at very high risk of having a CHD event; 10-year Framingham risk score; documentation of hepatotoxicity, myalgia, myositis, or rhabdomyolysis during maximum-dose therapy; concomitant medication during maximumdose therapy; relevant laboratory test values; and physician response to biochemical abnormalities or adverse events associated with maximum-dose therapy. RESULTS: Of the 232 outpatients identified, 173 were eligible for study inclusion. A total of 135 patients were classified as having a high or very-high risk of developing CHD (68 and 67, respectively). The success rates for low-density-lipoprotein (LDL) cholesterol goal attainment by very-high-risk patients and high-risk patients were 19.4% and 44.1%, respectively. Thirteen patients developed myalgia. Alanine transaminase levels were monitored for 38.8% of the study patients. Approximately 9% of patients were prescribed one interacting medication while on maximum-dose simvastatin or atorvastatin. The most commonly prescribed interacting drug was gemfibrozil. CONCLUSION: Despite the use of maximum-dose simvastatin or atorvastatin, target LDL cholesterol goals were not achieved and statin use was not adequately monitored in an ethnically diverse population with a high or very high risk of developing CHD.

Dual hypopigmentary effects of punicalagin via the ERK and Akt pathways.

Punicalagin is a phenolic compound with antioxidant properties. However, the effects of punicalagin on melanin synthesis have been poorly evaluated. Therefore, we investigated the effects of punicalagin on melanogenesis in Mel-Ab cells. Punicalagin significantly inhibited melanin synthesis in a dose-dependent manner. In accordance with the melanin content, punicalagin also dose-dependently decreased tyrosinase activity. Punicalagin did not directly inhibit tyrosinase in a cell-free system but did downregulate the expression of microphthalmia-associated transcription factor (MITF) and tyrosinase. Therefore, we examined the effects of punicalagin on melanogenesis-related signaling pathways. Punicalagin induced extracellular signal-regulated kinase (ERK) and Akt phosphorylation but had no effect on ß-catenin level. We measured melanin content and MITF expression in the presence of the ERK pathway inhibitor PD98059 and/or the Akt pathway inhibitor LY294002. Cotreatment with PD98059 and LY294002 almost completely restored punicalagin-induced hypopigmentation. These data indicate that punicalagin inhibits melanin synthesis through ERK and Akt phosphorylation, with subsequent downregulation of MITF and tyrosinase.

Comparison of sebum secretion, skin type, pH in humans with and without acne.

Differences of skin type and pH between subjects with and without acne have not been investigated. In addition, the relationship between sebum secretion and pH in these populations has not been determined. This study assessed the differences in objective and subjective skin types between these two groups. Secondly, this study evaluated the difference in pH on five facial areas (forehead, nose, chin, right and left cheeks) between the two populations. Lastly, the relationship between pH and sebum secretion was analyzed in each population. Sebum casual levels (CL) of the five facial areas in 36 Koreans with acne and 47 Koreans without acne were measured by using a Sebumeter SM 815 and subjects were classified into objective skin types by CL. Subjects reported the type of skin they believed they had, which determined the subjective skin type. The pH levels of the five facial areas were measured by the Skin-pH-Meter PH 905. Data were assessed with adequate statistical tests depending on data type and distribution. Among the five areas, the nose of the subjects with acne showed a significantly higher CL, compared to the subjects without acne. This difference in CL on the nose resulted in the difference in CL on the T-zone and mean facial sebum excretions (MFSE). Although CL differed, objective skin types did not differ between the two groups (P > 0.05), but the subjective skin types differed significantly (P = 0.001). In addition, the objective skin types were significantly different than the subjective skin types in subjects with acne (P = 0.001), whereas the two skin types did not differ in subjects without acne. Subjects with acne actually overestimated their skin types and stated their skin types were "oilier" than they were. In respect to pH, none of the five areas differed significantly between the two groups. Among the five sites in subjects with acne, CL showed a significant negative correlation with pH on the left (r (2 )=0.12) and right (r ( 2 )=0.15) cheeks, which resulted in a significant negative correlation on the U-zone (r ( 2 )=0.14). In contrast, in subjects without acne, there was a significant negative correlation between CL and pH on the forehead (r ( 2 )=0.10) and chin (r ( 2 )=0.16), which led to a significant negative correlation on the T-zone (r ( 2 )=0.14).

Co-Cr dental alloys induces cytotoxicity and inflammatory responses via activation of Nrf2/antioxidant signaling pathways in human gingival fibroblasts and osteoblasts.

OBJECTIVE: Although cobalt-chromium (Co-Cr) dental alloys are routinely used in prosthodontics, the biocompatibility of Co-Cr alloys is controversial. The aims of the present study were to investigate the effects of Co-Cr alloys on human gingival fibroblasts (HGF) and osteoblasts in an in vitro model as well as their potential molecular mechanisms, focusing on NF-E2-related factor 2 (Nrf2) pathways. METHODS: Cells were directly seeded on prepared Co-Cr alloy discs (15.0mm diameter, 1.0mm thickness) or indirectly treated with Co-Cr alloy located at the bottom of an insert well and incubated for 3 days. Cytotoxicity and reactive oxygen species (ROS) production was evaluated by MTS assay and flow cytometry, respectively. Protein and mRNA levels were determined by Western blotting and RT-PCR analysis, respectively. RESULTS: Cell viability and flow cytometric assay demonstrated that the Co-Cr alloy was cytotoxic to HGFs and osteoblasts, and significantly increased ROS production. In addition, the Co-Cr alloys upregulated pro-inflamamtory cytokines (TNF-α, IL-1ß, IL-6, and IL-8) and increased levels of various inflammatory mediators (iNOS derived nitrite oxide, and COX-2-derived PGE2) in both cells. A mechanistic study showed that Co-Cr alloys activates the NRF2 pathway and up-regulate antioxidant enzymes including heme oxygenase-1 (HO-1). Co-Cr alloys activated JAK2/STAT3, p38/ERK/JNK MAPKs and NF-κB signaling pathways. Furthermore, antioxidants (resveratrol and NAC) and HO-1 inhibitor (SnPP) significantly inhibited the production of ROS and inflammatory mediators, as well as the activation of NF-κB signaling in Co-Cr alloy stimulated HGFs and osteoblasts. SIGNIFICANCE: This study is the first to show that Co-Cr alloys exert cytotoxic and inflammatory effects via activation of Nrf2/ARE signaling and up-regulation of downstream HO-1, which could represent candidate targets for the regulation of inflammatory responses to Co-Cr alloys.

Effect of Titanium Dioxide Nanoparticle Exposure on the Ocular Surface: An Animal Study.

PURPOSE: To evaluate the effect of titanium dioxide (TiO2) nanoparticle exposure on the ocular surface. METHODS: Eighty eyes of 40 rabbits were used. The TiO2-1D group (n = 20) received a single instillation of TiO2 in the right eye. The TiO2-4D group (n = 20) received a TiO2 instillation in the right eye once a day for four days. The 40 untreated left eyes were used as controls. Ocular surface staining (n = 5 for each group) was performed with rose bengal dye, tear secretion (n = 5) was measured using the phenol red thread test, lactic dehydrogenase (LDH) activity (n = 5) and MUC5AC levels (n = 5) were measured in tears, and the area of the conjunctival goblet cells (n = 5) was measured through impression cytology and scanning electron microscopy 24 hours after the last TiO2 instillation. RESULTS: Ocular surface staining was increased but the tear secretion was not changed after TiO2 exposure. The TiO2-1D (1.39 OD) and TiO2-4D groups (0.58 OD) had higher median tear LDH activity than the control groups (0.57 OD and 0.29 OD, respectively). Although the median tear MUC5AC level in the TiO2-1D group (92.7 ng/ml) was higher than that of control 1 group (37.4 ng/ml), there was no significant difference in MUC5AC levels between the TiO2-4D and control 2 groups. Conjunctival goblet cell area decreased after TiO2 exposure. CONCLUSIONS: Exposure to TiO2 nanoparticles induced ocular surface damage. Although the tear MUC5AC level increased after a single exposure, it decreased to normal levels after repeated exposures. The area of conjunctival goblet cells decreased after TiO2 exposure.

Geranylgeranylacetone induces apoptosis via the intrinsic pathway in human melanoma cells.

The aim of this study was to test the anti-cancer effects of geranylgeranylacetone (GGA), an isoprenoid compound, on human melanoma cells. Human melanoma cell lines G361, SK-MEL-2, and SK-MEL-5 were treated with GGA at various doses (1-100µM). Cell viability was measured by crystal violet assay. Western blot analysis was adopted to detect marker proteins of apoptosis. GGA significantly reduced the viability of G361, SK-MEL-2, and SK-MEL-5 human melanoma cells at concentrations above 10µM. Western blot analysis showed the phosphorylation of p38 MAPK and c-Jun N-terminal kinase (JNK) after GGA treatment, as well as activation of caspase-9, caspase-3, and poly(ADP-ribose) polymerase (PARP) cleavage. GGA also induced p53 and Bax expression, but did not affect expression of Bcl-2 and MITF. These findings suggest that GGA induces apoptosis through the intrinsic pathway. Accordingly, GGA should be considered for further development as a potential agent for melanoma.

Use of Cumulative Assessments in U.S. Schools and Colleges of Pharmacy.

The Accreditation Council of Pharmacy Education (ACPE) has taken a strong stance on assessment in pharmacy education. One available assessment tool is cumulative assessments, which may be administered at various points in the curriculum. This article presents the results of a survey of U.S. schools of pharmacy regarding the use of cumulative assessments within their curriculum. A 20-question survey tool was emailed to 125 schools of pharmacy. A total of 105 out of 125 schools participated (response rate 84%). Of these, 52 schools currently have a cumulative assessment program; 18 have one cumulative exam prior to advanced pharmacy practice experiences (APPEs); 19 have a cumulative exam every didactic year; and seven have accumulative exams every semester, except during APPEs (n = 44). Increased faculty workload emerged as the top challenge faced by schools that have implemented a cumulative assessment program. Eighteen schools indicated that no outcomes are measured to determine the utility of the cumulative assessment. From these results, it appears that almost half of participating U.S. schools have implemented a cumulative assessment plan. However, it is apparent that more research needs to be done to determine which outcomes are expected to improve with the implementation of such an assessment plan.

Influence of sex on the pharmacokinetic interaction of fleroxacin and ciprofloxacin with caffeine.

BACKGROUND: Previous pharmacokinetic studies have shown that a number of the quinolones inhibit the metabolism of caffeine. OBJECTIVE: To evaluate the effect of sex on the interaction between two quinolones and caffeine. DESIGN: Multiple-dose, double-blind, randomised, three-period crossover study. PARTICIPANTS: Twelve male and twelve female healthy volunteers. METHODS: Subjects received by mouth either fleroxacin 400 mg once daily and caffeine 100 mg three times daily, ciprofloxacin 500 mg twice daily and caffeine 100 mg three times daily, or caffeine alone, for 3 days. Subjects received each of the other regimens after 12-day washout periods. Plasma and urine concentrations were determined by validated high-performance liquid chromatography procedures and the data were analysed by noncompartmental linear pharmacokinetic methods. RESULTS: Analysis of the interaction by sex revealed that females showed a significant difference in caffeine pharmacokinetics in the presence of ciprofloxacin (area under the concentration-time curve [AUC], peak plasma concentration [C(max)], time to C(max) [t(max)] and apparent total body clearance [CL/F]) and fleroxacin (AUC and CL/F) when compared with males. Significant differences between sexes were also observed in the pharmacokinetics of ciprofloxacin (AUC, elimination rate constant [beta] and CL/F) and fleroxacin (C(max) and beta) in the presence of caffeine. However, these significant differences disappeared when AUC and C(max) were normalised to 70 kg bodyweight and CL/F was expressed as per kg bodyweight. CONCLUSION: The effect of quinolones on the pharmacokinetics of caffeine, and the reciprocal effect, are different between the sexes, due in part to different bodyweights.

Pharmacokinetic and pharmacodynamic evaluation of two dosing regimens for piperacillin-tazobactam.

STUDY OBJECTIVE: To compare the pharmacokinetic and pharmacodynamic profiles of two dosing regimens for piperacillin-tazobactam against commonly encountered pathogens. The regimens compared were piperacillin 4.0 g-tazobactam 0.5 g administered every 8 hours, and piperacillin 3.0 g-tazobactam 0.375 g administered every 6 hours. DESIGN: Multiple-dose, open-label, randomized, crossover study. SETTING: Clinical research center at Hartford Hospital. SUBJECTS: Twelve healthy volunteers. INTERVENTION: The two dosing regimens for piperacillin-tazobactam were administered intravenously in crossover design. Blood was sampled after the third dose. MEASUREMENTS AND MAIN RESULTS: Drug concentrations were determined by a validated high-performance liquid chromatography assay. The percentage of time above minimum inhibitory concentration (%T>MIC) for piperacillin was calculated for a range of MIC values. The maximum concentration (Cmax), area under the concentration-time curve (AUC0-tau), and total clearance of piperacillin differed significantly between the two study regimens, as did the Cmax, AUC0-tau, volume of distribution, and total clearance of tazobactam (p<0.05). The piperacillin 4.0 g-tazobactam 0.5 g regimen provided 40-50% T>MIC for MIC values 8-16 microg/ml; a similar value for the piperacillin 3.0 g-tazobactam 0.375 g regimen was 16-32 microg/ml. CONCLUSION: Although statistically significant differences in the pharmacodynamic profile were noted for the regimens, both provide adequate T>MIC against commonly encountered pathogens considered susceptible to piperacillin-tazobactam. However, for treatment of Pseudomonas aeruginosa infection, combination therapy or higher-dosage regimens (e.g., piperacillin 3.0 g-tazobactam 0.375 g every 4 hours, piperacillin 4.0 g-tazobactam 0.5 g every 6 hours, or continuous-infusion piperacillin 12 g-tazobactam 1.5 g/day) may be a prudent option when full MIC data are unavailable.

Menadione (Vitamin K3) decreases melanin synthesis through ERK activation in Mel-Ab cells.

Menadione is a synthetic vitamin K3 derivative. Here, we examined the effects of menadione on melanogenesis and its related signaling pathways. Our results showed that melanin content was significantly reduced after menadione treatment in a dose-dependent manner. However, menadione treatment did not reduce tyrosinase activity directly. Wnt signaling is known to play a major role in the control of melanin synthesis. Thus, we tested the effects of menadione treatment on GSK3ß and ß-catenin signaling, but found that menadione did not influence either of these signaling pathways. We also investigated changes in the phosphorylation of ERK, which is related to melanin regulation. These results indicated that menadione treatment led to the phosphorylation of ERK. Additionally, menadione treatment reduced both MITF and tyrosinase protein levels. Treatment with PD98059, a specific ERK pathway inhibitor, restored menadione-induced melanin reduction and also prevented MITF and tyrosinase downregulation by menadione. These results suggest that the hypopigmentary action of menadione is due to MITF and tyrosinase downregulation by ERK activation.

Incorporation of Bloom's taxonomy into multiple-choice examination questions for a pharmacotherapeutics course.

OBJECTIVE: To incorporate Bloom's taxonomy into multiple-choice examination questions in a pharmacotherapeutics course and assess its effectiveness in detecting areas of improvement in learning. DESIGN: Bloom's taxonomy was incorporated into examination questions through a multi-step process: Sample questions representing each learning domain within Bloom's taxonomy (knowledge, comprehension, application, analysis, synthesis, and evaluation) were introduced to students during lecture presentations and discussions. Quiz and examination containing questions categorized according to Bloom's taxonomy were administered to students. During review sessions following each quiz or examination, the categorization of each question was provided to students and feedback from students was gathered. ASSESSMENT: The effect of the 5 types of test questions on the correct response fraction and discrimination index was determined after combining synthesis and evaluation. Correct response fractions for knowledge, comprehension, and application questions were significantly higher than those for analysis and synthesis/evaluation questions (p<0.05). However, discrimination index for application and synthesis/evaluation questions were significantly higher than those for knowledge and comprehension questions (p<0.05). In interviews with students who had requested learning assistance, the majority realized the importance of critical-thinking skills in the learning process. CONCLUSION: Well-designed multiple-choice questions incorporating different learning domains of Bloom's taxonomy may be a potential method of assessing critical-thinking skills in large classes of students.