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1.
J Exp Child Psychol ; 218: 105373, 2022 06.
Article in English | MEDLINE | ID: mdl-35168139

ABSTRACT

To understand complex and multifaceted nature of judgments about equality, this research investigated adolescents' judgments and reasoning about social inequalities among different social groups. Adolescents ranging in age from 12 to 17 years (N = 72) were presented with hypothetical situations depicting inequalities in distribution of resources among different groups based on social class, race, and gender. The situations bearing on social class inequalities involved allocation of resources associated with levels of personal wealth, and the other situations pertained to inequalities based on group characteristics of race and gender. Although the majority of adolescents negatively evaluated the inequalities in all situations, fewer judged the inequalities as unacceptable in the situations pertaining to social class inequalities involving personal goods. The evaluations about the inequalities based on race or gender were not contingent on conflicting personal choices, authority, rules, or common practices and were justified mostly with considerations of equality. However, when making judgments about inequalities based on social class, adolescents attended to the need to promote others' welfare and nonmoral concerns in the personal and conventional domains.


Subject(s)
Group Processes , Judgment , Adolescent , Child , Humans , Problem Solving , Social Class , Socioeconomic Factors
2.
Exp Dermatol ; 27(4): 396-402, 2018 04.
Article in English | MEDLINE | ID: mdl-28833499

ABSTRACT

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by intense pruritus and eczematous lesion. In this study, topically applied substance P (SP) significantly alleviated AD-like clinical symptoms in 2, 4, 6-trinitrochlorobenzene (TNCB)-induced dermatitis in NC/Nga mice. This effect was nullified by pretreatment of the neurokinin-1 receptor (NK-1R) antagonist CP99994. SP treatment significantly reduced the infiltration of mast cells and CD3-positive T cells as well as inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and thymic stromal lymphopoietin (TSLP), in AD-like skin lesions and decreased the levels of IgE and thymus and activation-regulated chemokine in serum. This SP-induced alleviation of allergic inflammatory responses was also confirmed as reduced activation in the axillary lymph nodes (aLN) and spleen, suggesting the systemic effect of SP on immune responses in TNCB-induced NC/Nga mice. Furthermore, SP-mediated TSLP reduction was confirmed in human keratinocyte culture under pro-inflammatory TNF-α stimulation. Taken together, these results suggest that topically administered SP may have potential as a medication for atopic dermatitis.


Subject(s)
Cell Degranulation/drug effects , Dermatitis, Atopic/drug therapy , Mast Cells/physiology , Neurotransmitter Agents/therapeutic use , Substance P/therapeutic use , Administration, Cutaneous , Animals , CD3 Complex/metabolism , Cells, Cultured , Chemokine CCL17/blood , Cytokines/metabolism , Dermatitis, Atopic/chemically induced , Dermatitis, Atopic/immunology , Dermatitis, Atopic/pathology , Humans , Immunoglobulin E/blood , Keratinocytes/metabolism , Male , Mast Cells/pathology , Mice , Neurokinin-1 Receptor Antagonists/pharmacology , Neurotransmitter Agents/pharmacology , Picryl Chloride , Substance P/pharmacology , T-Lymphocytes/metabolism , Tumor Necrosis Factor-alpha/metabolism , Tumor Necrosis Factor-alpha/pharmacology , Thymic Stromal Lymphopoietin
3.
Int J Mol Sci ; 19(10)2018 Oct 14.
Article in English | MEDLINE | ID: mdl-30322210

ABSTRACT

Distal-less homeobox 5 (Dlx5) is a negative regulator of adipogenesis. Dlx5 expression is decreased by adipogenic stimuli, but the mechanisms of Dlx5 downregulation by adipogenic stimuli have not yet been determined. Here, we tested the impact of cAMP/PKA (protein kinase A) signaling induced by 3-isobutyl-1 methyl xanthine (IBMX), forskolin, and 8-CPT-cAMP on the expression of Dlx5 in 3T3-L1 preadipocytes. Significant downregulation of Dlx5 mRNA expression and protein production levels were observed via cAMP/PKA-dependent signaling. Forced expression of cAMP-responsive element-binding protein (CREB) and CCAAT/enhancer-binding protein ß (C/EBPß) was sufficient for downregulation of Dlx5 expression and revealed that CREB functions upstream of C/EBPß. In addition, C/EBPß knockdown by siRNA rescued Dlx5 expression in IBMX-treated 3T3-L1 preadipocytes. Luciferase assays using a Dlx5-luc-2935 reporter construct demonstrated the requirement of the Dlx5 promoter region, ranging from -774 to -95 bp that contains two putative C/EBPß binding elements (site-1: -517 to -510 bp and site-2: -164 to -157 bp), in the suppression of Dlx5 transcription. Consequently, chromatin immunoprecipitation analysis confirmed the importance of site-1, but not site-2, in C/EBPß binding and transcriptional suppression of Dlx5. In conclusion, we elucidated the underling mechanism of Dlx5 downregulation in IBMX-induced adipogenesis. IBMX activated cAMP/PKA/CREB signaling and subsequently upregulated C/EBPß, which binds to the Dlx5 promoter to suppress Dlx5 transcription.


Subject(s)
Adipocytes/cytology , CCAAT-Enhancer-Binding Protein-beta/metabolism , Cyclic AMP Response Element-Binding Protein/metabolism , Cyclic AMP-Dependent Protein Kinases/metabolism , Homeodomain Proteins/genetics , 1-Methyl-3-isobutylxanthine/pharmacology , 3T3-L1 Cells , Adipocytes/drug effects , Adipocytes/metabolism , Adipogenesis , Animals , Binding Sites , CCAAT-Enhancer-Binding Protein-beta/genetics , Colforsin/pharmacology , Cyclic AMP/analogs & derivatives , Cyclic AMP/pharmacology , Cyclic AMP Response Element-Binding Protein/genetics , Gene Expression Regulation/drug effects , Homeodomain Proteins/chemistry , Homeodomain Proteins/metabolism , Mice , Signal Transduction/drug effects , Thionucleotides/pharmacology
4.
J Cell Biochem ; 117(1): 230-8, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26104915

ABSTRACT

Heat shock protein 90 (HSP90) regulates the stability of various proteins and plays an essential role in cellular homeostasis. Many client proteins of HSP90 are involved in cell growth, survival, and migration; processes that are generally accepted as participants in tumorigenesis. HSP90 is also up-regulated in certain tumors. Indeed, the inhibition of HSP90 is known to be effective in cancer treatment. Recently, studies showed that HSP90 regulates transforming growth factor ß1 (TGF-ß1)-induced transcription by increasing the stability of the TGF-ß receptor. TGF-ß signaling also has been implicated in cancer, suggesting the possibility that TGF-ß1 and HSP90 function cooperatively during the cancer cell progression. Here in this paper, we investigated the role of HSP90 in TGF-ß1-stimulated Mv1Lu cells. Treatment of Mv1Lu cells with the HSP90 inhibitor, 17-allylamino-demethoxy-geldanamycin (17AAG), or transfection with truncated HSP90 (ΔHSP90) significantly reduced TGF-ß1-induced cell migration. Pretreatment with 17AAG or transfection with ΔHSP90 also reduced the levels of phosphorylated Smad2 and Smad3. In addition, the HSP90 inhibition interfered the nuclear localization of Smads induced by constitutively active Smad2 (S2EE) or Smad3 (S3EE). We also found that the HSP90 inhibition decreased the protein level of importin-ß1 which is known to regulate R-Smad nuclear translocation. These data clearly demonstrate a novel function of HSP90; HSP90 modulates TGF-ß signaling by regulating Smads localization. Overall, our data could provide a detailed mechanism linking HSP90 and TGF-ß signaling. The extension of our understanding of HSP90 would offer a better strategy for treating cancer.


Subject(s)
HSP90 Heat-Shock Proteins/metabolism , Smad2 Protein/metabolism , Smad3 Protein/metabolism , Animals , Benzoquinones/pharmacology , HSP90 Heat-Shock Proteins/antagonists & inhibitors , HSP90 Heat-Shock Proteins/genetics , Lactams, Macrocyclic/pharmacology , Phosphorylation/drug effects , Receptors, Transforming Growth Factor beta/metabolism , Signal Transduction/drug effects , Transforming Growth Factor beta/metabolism , Transforming Growth Factor beta1/metabolism
5.
South Med J ; 108(4): 207-10, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25871986

ABSTRACT

OBJECTIVES: We hypothesized that medical students exposed to a case-based curriculum in years 1 and 2 and clinical cases in the year 3 clerkship would demonstrate a longitudinal increase in the deep approach to learning and a decrease in the surface apathetic approach. METHODS: A cohort of first-year medical students completed the Approaches and Study Skills Inventory for Students at the beginning of their first term and again at the beginning of their fourth year. Approaches and Study Skills Inventory for Students scores were aggregated into three main learning approach scales: deep, strategic, and surface apathetic. RESULTS: On average, deep and strategic scores did not significantly change between years 1 and 4, but the surface apathetic mean score decreased as a result of lower syllabus boundness and fear of failure subscale scores. Effect sizes were small (d = 0.30, 0.34, respectively). CONCLUSIONS: The deep approach to learning is a complex process and did not change in our students after 3 years of medical school, even though a case-based curriculum was believed to foster deeper learning. By the end of year 3, our students were, on average, less bound to syllabi and feared failure less.


Subject(s)
Education, Medical, Undergraduate/methods , Learning , Students, Medical/psychology , Teaching/methods , Adult , Educational Measurement/methods , Female , Humans , Longitudinal Studies , Male , Problem-Based Learning/methods , Prospective Studies , Surveys and Questionnaires , Young Adult
6.
Exp Cell Res ; 319(4): 466-73, 2013 Feb 15.
Article in English | MEDLINE | ID: mdl-23262026

ABSTRACT

Transforming growth factor-ß1 (TGF-ß1) regulates various biological processes, including differentiation, bone remodeling and angiogenesis, and is particularly important as a regulator of homeostasis and cell growth in normal tissue. Interestingly, some studies have reported that TGF-ß1 induces apoptosis through induction of specific genes, whereas others suggest that TGF-ß1 inhibits apoptosis and facilitates cell survival. Resolving these discrepancies, which may reflect differences in cellular context, is an important research priority. Here, using the parental mink lung epithelial cell line, Mv1Lu, and its derivatives, R1B and DR26, lacking TGF-ß receptors, we investigated the involvement of TGF-ß signaling in the effects of γ-irradiation. We found that canonical TGF-ß signaling played an important role in protecting cells from γ-irradiation. Introduction of functional TGF-ß receptors or constitutively active Smads into R1B and DR26 cell lines reduced DNA fragmentation, Caspase-3 cleavage and γ-H2AX foci formation in γ-irradiated cells. Notably, we also found that de novo protein synthesis was required for the radio-resistant effects of TGF-ß1. Our data thus indicate that TGF-ß1 protected against γ-irradiation, decreasing DNA damage and reducing apoptosis, and thereby enhanced cell survival.


Subject(s)
Gamma Rays , Radiation Tolerance , Transforming Growth Factor beta/physiology , Animals , Apoptosis/drug effects , Apoptosis/genetics , Apoptosis/radiation effects , Cell Survival/drug effects , Cell Survival/genetics , Cell Survival/radiation effects , Cells, Cultured , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Epithelial Cells/physiology , Epithelial Cells/radiation effects , Lung/cytology , Lung/drug effects , Lung/metabolism , Lung/radiation effects , Mink , Radiation Tolerance/drug effects , Radiation Tolerance/genetics , Radiation Tolerance/physiology , Radiation-Protective Agents/metabolism , Radiation-Protective Agents/pharmacology , Receptors, Transforming Growth Factor beta/genetics , Receptors, Transforming Growth Factor beta/metabolism , Receptors, Transforming Growth Factor beta/physiology , Signal Transduction/drug effects , Signal Transduction/genetics , Signal Transduction/physiology , Transfection , Transforming Growth Factor beta/metabolism , Transforming Growth Factor beta/pharmacology
7.
PLoS One ; 19(4): e0301502, 2024.
Article in English | MEDLINE | ID: mdl-38603669

ABSTRACT

Duty hour regulations (DHRs) were enforced in 2017 in Korea to prevent the detrimental effects of excessively prolonged working hours among medical residents. We investigated the adoption of and implications of the new DHRs among medical residents and faculty members. Semi-structured interviews were conducted with 15 medical residents and 9 faculty members across general surgery, internal medicine, obstetrics-gynecology, and pediatrics departments at Chonnam National University Hospital. Based on the constructivist grounded theory, we developed themes from the data by concurrent coding and analysis with theoretical sampling until data saturation. In addition, respondent validation was used to ensure accuracy, and all authors remained reflexive throughout the study to improve validity. The methods of DHRs adoption among residents and faculty members included the following 4 themes: DHRs improved work schedule, residents have more time to learn on their own, clinical departments have come to distribute work, organization members have strived to improve patient safety. Residents have undertaken initial steps towards creating a balance between personal life and work. Teamwork and shift within the same team are the transitions that minimize discontinuity of patient care considering patient safety. Teaching hospitals, including faculty members, should ensure that residents' work and education are balanced with appropriate clinical experience and competency-based training.


Subject(s)
Internship and Residency , Workload , Child , Humans , Personnel Staffing and Scheduling , Faculty, Medical , Republic of Korea
8.
PLoS One ; 19(2): e0298067, 2024.
Article in English | MEDLINE | ID: mdl-38349912

ABSTRACT

We implemented flipped learning for a gross anatomy dissection course and compared its effects on students' motivation and academic achievement with those of traditional dissection methods. We invited 142 first-year medical students at Chonnam National University Medical School to participate in this study. All participants engaged in traditional dissection methods in the first part of the study and flipped learning in the latter part. Medical students' motivation to learn anatomy by cadaveric dissection was measured using the ARCS (Attention, Relevance, Confidence, and Satisfaction) model. Thereafter, all students completed a written examination consisting of 96 multiple-choice questions. The students' mean motivational score regarding attention was significantly higher in association with flipped learning than with traditional learning. However, the students' mean motivational scores regarding relevance, confidence, and satisfaction were not significantly different between the methods. Additionally, the mean anatomy practice test score was significantly higher in association with flipped learning than with traditional learning. The students' motivational scores and anatomy practice test scores associated with flipped learning positively correlated with the extent of learning material completion. The students' responses indicated that flipped learning helped enhance the learning process, improve time management, reduce confusion during practice, and promote independent practice. The application of flipped learning to a cadaveric dissection course increased individual learning motivation, which improved learning activities both in and out of class, as well as academic achievement.


Subject(s)
Anatomy , Students, Medical , Humans , Educational Measurement , Learning , Dissection , Curriculum , Cadaver , Problem-Based Learning/methods , Anatomy/education
9.
PLoS One ; 19(2): e0296682, 2024.
Article in English | MEDLINE | ID: mdl-38335189

ABSTRACT

Longitudinal research has provided systematic empirical data on the short- and long-term outcomes of admissions policies, curricular innovations, and complex decisions on students' academic progress. This study aimed to investigate the academic performance of medical students and related factors using cohort database collected from a medical school. The study participants included 134 medical students who graduated from Chonnam National University Medical School in 2022. The medical school's cohort database was used to collect data on demographics, admission, academic performance, extracurricular activities, and performance on the National Korean Medical Licensing Examination (KMLE). Participating in club activities had a significant association with medical students' academic advancement delay or leave of absence during the entire course of medical school (P = 0.007). Logistic regression analysis indicated that the nationwide clinical knowledge mock examination during the fourth year of medical school was significantly associated with passing the KMLE (adjusted odds ratio 1.12, 95% confidence interval 1.02-1.22; P = 0.014). Extracurricular school activities (a non-cognitive student attribute) and a wide range of cognitive student attributes captured from the cohort database were associated with medical students' academic performance. In conclusion, this study can reinforce a strong emphasis on the inclusion of cognitive and non-cognitive information in medical school curricula and assessments in order to improve medical education programs and future postgraduate performance.


Subject(s)
Academic Performance , Students, Medical , Humans , Retrospective Studies , Students, Medical/psychology , Schools, Medical , Universities
10.
Clin Anat ; 26(3): 327-32, 2013 Apr.
Article in English | MEDLINE | ID: mdl-22576822

ABSTRACT

We presented two kinds of advance organizers (AOs), video clips and prosection, for a gross anatomy dissection course and compared their effects on academic achievement and student perception of the learning experience. In total, 141 students at Chonnam National University Medical School were randomly assigned to two groups: Group 1 (n = 70) was provided with video clips AO, whereas Group 2 (n = 71) was provided with prosection AO, the use of cadaveric specimens dissected by the course instructor. Student self-assessment scores regarding the learning objectives of upper limb anatomy improved significantly in both groups. Academic achievement scores in Group 2 were significantly higher than those in Group 1, although the self-assessment scores were not significantly different between the groups. Additionally, students in Group 2 responded significantly more positively to the statements about perception of the learning experience such as helping them understand the course content and concepts, decreasing anxiety about the dissection course, and participating actively in the dissection. It would seem that the application of prosection as an AO improved academic achievement and increased student engagement and satisfaction. This study will contribute to designing effective AOs and developing a teaching and learning strategy for a gross anatomy dissection course.


Subject(s)
Anatomy/education , Dissection/education , Achievement , Adult , Educational Measurement , Female , Humans , Male , Prospective Studies , Random Allocation , Teaching/methods , Upper Extremity/anatomy & histology , Videotape Recording , Young Adult
11.
Eur J Clin Pharmacol ; 68(2): 149-54, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21842338

ABSTRACT

PURPOSE: To evaluate the effects of two major polymorphisms of CYP2C9, CYP2C9 3 and CYP2C9 13, on the pharmacokinetics of irbesartan in healthy Korean volunteers. METHODS: A single 150-mg oral dose of irbesartan was given to 28 Korean volunteers, who had different CYP2C9 genotypes (12, 10, and 6 carriers of CYP2C9 1/ 1, 1/ 3, and 1/13 genotypes respectively). Irbesartan levels were analyzed using HPLC fluorescence in plasma samples collected up to 36 h after the drug intake. RESULTS: Compared with CYP2C9 1 homozygous subjects, not only were the maximum plasma concentrations (C(max)) of irbesartan in CYP2C9 1/ 3 and 1/ 13 subjects 1.56- and 1.50-fold higher (P = 0.001), but the half-lives were also 1.38- and 1.50-fold longer (P = 0.001). The area under the plasma concentration-time curve (AUC) was 1.64- and 1.79-fold higher (P < 0.001). The oral clearance of irbesartan was 39.3% and 44.0% lower in the CYP2C9 1/ 3 and 1/ 13 subjects respectively, than in the 1/ 1 subjects (P < 0.001). Likewise, the increases in half-life and decreases in oral clearance observed in CYP2C9 1/ 13 individuals were similar to those in participants expressing the CYP2C9 1/ 3 genotype. CONCLUSIONS: CYP2C9 genetic polymorphisms markedly affected the pharmacokinetics of irbesartan in this study sample. The CYP2C9 3 and CYP2C9 13 alleles appear to be associated with the decreased metabolism of irbesartan.


Subject(s)
Angiotensin II Type 1 Receptor Blockers/pharmacokinetics , Antihypertensive Agents/pharmacokinetics , Aryl Hydrocarbon Hydroxylases/genetics , Biphenyl Compounds/pharmacokinetics , Tetrazoles/pharmacokinetics , Alleles , Angiotensin II Type 1 Receptor Blockers/blood , Antihypertensive Agents/blood , Area Under Curve , Asian People/genetics , Biphenyl Compounds/blood , Cytochrome P-450 CYP2C9 , Genotype , Half-Life , Humans , Irbesartan , Polymorphism, Genetic , Tetrazoles/blood
12.
Med Teach ; 34(4): e236-41, 2012.
Article in English | MEDLINE | ID: mdl-22455715

ABSTRACT

BACKGROUND: A learning approach embeds the intention of the student when starting a task and the learning processes and strategies used to carry out a task. Student approaches to learning have been categorized as deep, strategic, and surface. AIM: To explore the relationships among medical students' learning approaches, gender, and performance on a summative high-stakes clinical performance examination (CPX). METHODS: We measured medical students' learning approaches at the beginning of year four using the Approaches and Study Skills Inventory for Students and compared results with CPX scores. RESULTS: Student scores in the top two quartiles of the CPX were significantly higher on the deep approach than student CPX scores in the bottom quartile, and student scores in the bottom quartile of the CPX were significantly higher on the surface approach than scores for the other three CPX quartiles. CPX patient-physician interaction scores showed a significant positive correlation with deep approach scores, and CPX overall patient satisfaction scores showed a significant positive correlation with deep and strategic approach scores. Surface approach scores correlated negatively with all CPX score categories. CONCLUSION: Approach to learning was associated with performance on a high-stakes CPX.


Subject(s)
Clinical Competence/standards , Education, Medical, Undergraduate/methods , Learning , Students, Medical/psychology , Test Taking Skills , Analysis of Variance , California , Educational Measurement/methods , Female , Humans , Male , Sex Factors
13.
Infect Chemother ; 54(3): 419-432, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35920267

ABSTRACT

BACKGROUND: This study explored the relationship between integrase strand transfer inhibitor (INSTI)-based anti-retroviral agents and weight gain over time, and the risk factors for weight gain in Korean people living with human immunodeficiency virus (PLWH). MATERIALS AND METHODS: The study was conducted retrospectively in PLWHs 18 years of age or older who took one of three INSTI-based single-tablet regimens (STRs) (tenofovir disoproxil fumarate/emtricitabine/elvitegravir/cobicistat [TDF/F/EVG/c], tenofovir alafenamide/emtricitabine/elvitegravir/cobicistat [TAF/F/EVG/c], and abacavir/lamivudine/dolutegravir [ABC/3TC/DTG]) for more than 2 years at three university-affiliated hospitals in South Korea from May 2014 to December 2020. Analysis was performed in the treatment-naïve and treatment-experienced groups, respectively. RESULTS: Individual INSTI-based STRs were associated with weight gain at the 24-month follow up in both treatment-naïve (n = 179) and treatment-experienced (n = 290) groups. Body mass index (BMI) categories changed over time for TAF/F/EVG/c and ABC/3TC/DTG, with significant increases in the rates of overweight and obesity in treatment-naïve patients, whereas there was no change for TDF/F/EVG/c. TAF/F/EVG/c significantly increased total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) compared to other regimens over 24 months. In the treatment-naïve group, a baseline CD4+ T cell count <100 cells/mm3, human immunodeficiency virus (HIV) viral load (VL) ≥100,000 copies/mL, no physical exercise, and TAF/F/EVG/c (vs. TDF/F/EVF/c) were risk factors for ≥10% weight gain. In the treatment-experienced group, age <45 years, BMI <25 kg/m², and no physical exercise were risk factors for ≥5% weight gain. CONCLUSION: INSTI-based STR continued to increase body weight at the 24-month follow up in treated and untreated Korean PLWH. Exercise, together with demographic-, HIV-, and anti-retroviral therapy-related factors, influenced weight gain. Therefore, when prescribing an INSTI-based STR, weight gain and metabolic changes should be closely monitored in PLWH with these risk factors.

14.
Korean J Med Educ ; 33(2): 115-124, 2021 Jun.
Article in English | MEDLINE | ID: mdl-34062643

ABSTRACT

PURPOSE: The purpose of this study was to investigate the effect of motivational regulation strategies (MRSs) on cognitive learning and academic performance. METHODS: The participants were a total of 510 pre-medical and medical students. Survey instruments assessed the use of MRSs and cognitive learning strategies. Students' grade point averages were used for academic performance. Structural equation modeling was used to analyze data, using Mplus ver. 7.4 (Muthén & Muthén, Los Angeles, USA). RESULTS: Confirming the measurement model validity, the results of structural model indicated the followings: (1) MRSs had a significant impact on cognitive learning, while these strategies negatively affected academic performance; (2) cognitive learning significantly influenced academic performance and mediated the effect of MRSs on academic performance; and (3) only academic levels had a significant effect on cognitive learning. CONCLUSION: The findings from this study confirmed that MRSs were highly influential to predicting students' cognitive learning which affects their better learning performance. Thus, instructional design and practice to support learning motivation is needed to promote cognitive learning and training programs to practice the effective methods of using MRSs in learning need to be provided.


Subject(s)
Academic Performance , Education, Distance , Students, Medical , Cognition , Humans , Motivation
15.
Int J Stem Cells ; 14(1): 94-102, 2021 Feb 28.
Article in English | MEDLINE | ID: mdl-33377452

ABSTRACT

BACKGROUND AND OBJECTIVES: Human mesenchymal stem cell-conditioned medium (MSC-CM) is produced using mesenchymal stem cell culture technology and has various benefits for the skin, including wrinkle removal, skin regeneration, and increased antioxidant activity. Its popularity is thus increasing in the field of functional cosmetics. METHODS AND RESULTS: In this study, we analyzed the effects of fetal bovine serum-supplemented MSC-CM (FBSMSC-CM) and human platelet lysate-supplemented MSC-CM (hPL-MSC-CM) on skin rejuvenation characteristics. We found that the concentrations of important growth factors (VEGF, TGF-ß1, and HGF) and secretory proteins for skin regeneration were significantly higher in hPL-MSC-CM than in FBS-MSC-CM. Furthermore, the capacity for inducing proliferation of human dermal fibroblast (HDF) and keratinocytes, the migration ability of HDF, extracellular matrix (ECM) production such as collagen and elastin was higher in hPL-MSC-CM than that in FBSMSC-CM. CONCLUSIONS: These results support the usefulness and high economic value of hPL-MSC-CM as an alternative source of FBS-MSC-CM in the cosmetic industry for skin rejuvenation.

16.
Int J Stem Cells ; 14(1): 103-111, 2021 Feb 28.
Article in English | MEDLINE | ID: mdl-33377453

ABSTRACT

BACKGROUND AND OBJECTIVES: Mesenchymal stem cells (MSCs) have immense therapeutic potential for treating intractable and immune diseases. They also have applications in regenerative medicine in which distinct treatments do not exist. Thus, MSCs are gaining attention as important raw materials in the field of cell therapy. Importantly, the number of MSCs in the bone marrow is limited and they are present only in small quantities. Therefore, mass production of MSCs through long-term culture is necessary to use them in cell therapy. However, MSCs undergo cellular senescence through repeated passages during mass production. In this study, we explored methods to prolong the limited lifetime of MSCs by culturing them with different seeding densities. METHODS AND RESULTS: We observed that in long-term cultures, low-density (LD, 50 cells/cm2) MSCs showed higher population doubling level, leading to greater fold increase, than high-density (HD, 4,000 cells/cm2) MSCs. LD-MSCs suppressed the expression of aging-related genes. We also showed that reactive oxygen species (ROS) were decreased in LD-MSCs compared to that in HD-MSCs. Further, proliferation potential increased when ROS were inhibited in HD-MSCs. CONCLUSIONS: The results in this study suggest that MSC senescence can be delayed and that life span can be extended by controlling cell density in vitro. These results can be used as important data for the mass production of stem cell therapeutic products.

17.
J Dermatol ; 48(8): 1236-1242, 2021 Aug.
Article in English | MEDLINE | ID: mdl-33990997

ABSTRACT

Atopic dermatitis is a chronic and relapsing inflammatory skin disease that is treated with immunosuppressants. However, long-term use of immunosuppressants may cause toxicity and severe side-effects. To confirm the long-term efficacy and safety of clonal mesenchymal stem cell therapy, we performed investigator-initiated clinical trials and long-term observation in five adult patients with moderate to severe atopic dermatitis that was refractory to conventional treatments. The clinical response assessment values such as Eczema Area and Severity Index (EASI) improved significantly at 16 weeks, and 80% (4/5) of the patients achieved EASI-50 after one or two treatment cycles. Patients were observed for long-term efficacy and safety for an average of 38 weeks (range, 16-86) and showed no serious side-effects. Among the cytokines tested, CCL-17, interleukin (IL)-13, and IL-22 significantly decreased at the end-point of the five participants, two patients who maintained good clinical response over 84 weeks showed increased IL-17 cytokine levels in the blood.


Subject(s)
Dermatitis, Atopic , Mesenchymal Stem Cells , Adult , Bone Marrow , Dermatitis, Atopic/drug therapy , Double-Blind Method , Humans , Injections, Intravenous , Severity of Illness Index , Treatment Outcome
18.
Korean J Med Educ ; 32(1): 67-72, 2020 Mar.
Article in English | MEDLINE | ID: mdl-32130852

ABSTRACT

PURPOSE: This study investigated the perceptions of medical residents and faculty members before the implementation of the duty hour regulation in December 2017. METHODS: A survey was administered to 263 residents and 358 faculty members in the Chonnam National University Hospital. The subjects were given a self-administered structured questionnaire designed to measure their perspectives on duty hour regulation. They were also asked to answer an open-ended question regarding their expectations or concerns regarding duty hour regulation. The response rates were 50.2% for residents and 24.0% for faculty members. RESULTS: Residents and faculty members regarded the improvement of junior residents' well-being favorably, but had conflicting views regarding senior residents. Residents expressed difficulty in completing unchanged workloads within the limited time, while faculty members were more concerned about worsening patient safety due to the discontinuity of care and insufficient resident education. CONCLUSION: Medical residents and faculty members had differing concerns regarding duty hour regulation. Further studies and the development of future policies should be considered to improve resident education and patient safety within the limited duty hour regulation.


Subject(s)
Attitude of Health Personnel , Education, Medical, Graduate/organization & administration , Faculty, Medical/psychology , Internship and Residency/organization & administration , Students, Medical/psychology , Workload , Adult , Female , Humans , Male , Middle Aged , Patient Safety , Republic of Korea , Surveys and Questionnaires
19.
Biochem Biophys Res Commun ; 386(3): 455-8, 2009 Aug 28.
Article in English | MEDLINE | ID: mdl-19527683

ABSTRACT

Imiquimod (IMQ) is recognized as a topical immune response modifier compound that enhances immune responses with anti-viral and anti-tumoral activities. Its anti-tumoral effects have been previously demonstrated in a variety of cancer cells, and were identified as indirect responses mediated by the immune modulation of cutaneous dendritic cells. Recently, the pro-apoptotic activities of IMQ occurring via the modulation of bcl-2 family have been reported in several tumor cells. In this study, we first observed IMQ-initiated autophagy determined by vesicular organelle formation and the generation of LC3-II in Caco-2 human colonic adenocarcinoma cells, which expressing functional TLR7. Additionally, IMQ-induced autophagy resulted in cell death occurring independently of molecular changes of apoptotic markers. Loxoribine also induced autophagy and autophagy-induced cell death at less potent than IMQ. Moreover, the activation of autophagy by rapamycin induced enhanced cell death in TNF-alpha-treated Caco-2 cells, which were autophagy and cell death-resistant. Our results led us to conclude that IMQ exerts a direct effect on the anti-tumoral activity of Caco-2 cells via autophagy-induced cell death. In conclusion, the modulation of autophagy might be applied in a potential cancer therapy for the treatment of colon cancer cells.


Subject(s)
Aminoquinolines/pharmacology , Antineoplastic Agents/pharmacology , Autophagy , Toll-Like Receptor 7/agonists , Caco-2 Cells , Humans , Imiquimod , Ligands
20.
Biochem Biophys Res Commun ; 384(2): 231-5, 2009 Jun 26.
Article in English | MEDLINE | ID: mdl-19394307

ABSTRACT

Syndecan-2, a transmembrane heparan sulfate proteoglycan, is known to serve as an adhesion receptor, but details of the regulatory mechanism governing syndecan-2 cell adhesion and migration remain unclear. Here, we examined this regulatory mechanism, showing that overexpression of syndecan-2 enhanced collagen adhesion, cell migration and invasion of normal rat intestinal epithelial cells (RIE1), and increased integrin alpha2 expression levels. Interestingly, RIE1 cells transfected with either syndecan-2 or integrin alpha2 showed similar adhesion and migration patterns, and a function-blocking anti-integrin alpha2 antibody abolished syndecan-2-mediated adhesion and migration. Consistent with these findings, transfection of integrin alpha2 siRNA diminished syndecan-2-induced cell migration in HCT116 human colon cancer cells. Taken together, these results demonstrate a novel cooperation between syndecan-2 and integrin alpha2beta1 in adhesion-mediated cell migration and invasion. This interactive dynamic might be a possible mechanism underlying the tumorigenic activities of colon cancer cells.


Subject(s)
Cell Movement , Enterocytes/physiology , Integrin alpha2/metabolism , Syndecan-2/biosynthesis , Animals , Cell Adhesion , Cell Line, Tumor , Collagen/chemistry , Collagen/metabolism , Colonic Neoplasms/metabolism , Colonic Neoplasms/pathology , Enterocytes/metabolism , Humans , Integrin alpha2/genetics , Neoplasm Invasiveness , RNA, Small Interfering/genetics , Rats , Syndecan-2/genetics
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