Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Anat Sci Educ ; 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38487974

RESUMO

It can be difficult for some students to learn three-dimensional anatomical structure concepts. While virtual reality (VR) systems have been reported as helpful for learning, there has been scarce research on either VR teaching strategies or the influence of visually induced motion sickness (VIMS) in the context of large anatomy classes (i.e., over 100 students). The study thus aimed to (1) establish a VR anatomy instruction video for a large class; (2) determine how many students experience VIMS when watching a VR anatomy instruction video; (3) evaluate the influence of VIMS on VR anatomy video-based learning; and (4) examine whether a small screen size alleviates VIMS. Laboratory course students viewing a VR anatomy instruction video about the vascular system were invited to participate in the questionnaire survey. Anatomy faculty and staff participated in an experimental trial to determine whether small screen size could alleviate VIMS. The Likert scale survey revealed that students reported the VR strategy as advantageous and appropriate for large classes, but that it cannot replace practical dissection. Of the total participants, 32% reported experiencing VIMS, and 40% of those experiencing VIMS agreed that this could negatively impact their learning through a VR anatomy instruction video. Adjusting the screen size from large to small significantly delayed the onset of VIMS. In conclusion, the VR anatomy instruction video strategy is feasible and helpful for large classes, but educators should consider VIMS when planning their use of this teaching approach.

2.
Mol Neurobiol ; 61(2): 707-724, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37656312

RESUMO

The role of heat shock protein 27 (HSP27), a chaperone, in neuropathic pain after nerve injury has not been systematically surveyed despite its neuroprotective and regeneration-promoting effects. In this study, we found that HSP27 expression in sensory neurons of the dorsal root ganglia (DRG) mediated nerve injury-induced neuropathic pain. Neuropathic pain behaviors were alleviated by silencing HSP27 in the DRG of a rat spinal nerve ligation (SNL) model. Local injection of an HSP27-overexpression construct into the DRG of naïve rats elicited neuropathic pain behaviors. HSP27 interacted with a purinergic receptor, P2X3, and their expression patterns corroborated the induction and reversal of neuropathic pain according to two lines of evidence: colocalization immunohistochemically and immunoprecipitation biochemically. In a cell model cotransfected with HSP27 and P2X3, the degradation rate of P2X3 was reduced in the presence of HSP27. Such an alteration was mediated by reducing P2X3 ubiquitination in SNL rats and was reversed after silencing HSP27 in the DRGs of SNL rats. In summary, the interaction of HSP27 with P2X3 provides a new mechanism of injury-induced neuropathic pain that could serve as an alternative therapeutic target.


Assuntos
Proteínas de Choque Térmico HSP27 , Neuralgia , Animais , Ratos , Gânglios Espinais/metabolismo , Proteínas de Choque Térmico HSP27/metabolismo , Hiperalgesia/metabolismo , Neuralgia/metabolismo , Ratos Sprague-Dawley , Nervos Espinhais/metabolismo , Receptores Purinérgicos P2X3/metabolismo
3.
Eur J Dent Educ ; 27(4): 1077-1087, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36976652

RESUMO

INTRODUCTION: Modified teaching strategies (MTS), asynchronous online teaching and smaller dissection groups, were applied to a gross anatomy course for dental students in the National Taiwan University in April 2020 in response to the COVID-19 pandemic. This study aimed to investigate the effects and perceptions of MTS on dental students. MATERIALS AND METHODS: Scores for anatomy examinations for 2018-2019 (without MTS) and 2019-2020 (with MTS) cohorts were compared to explore the effect on academic performance. Moreover, questionnaire from the 2019-2020 cohort was analysed to determine dental students' perceptions about MTS. RESULTS: The lecture performance in the final examination of the second semester for the 2019-2020 cohort was significantly higher than that of the first semester (pre-COVID-19) and that for the 2018-2019 cohort. However, the laboratory performance in the midterm examination of the second semester for the 2019-2020 cohort was significantly lower than that for the 2018-2019 cohort and showed no difference in the final examination of the first semester. The questionnaires revealed that the majority of students displayed positive attitudes towards MTS and agreed with the importance of peer discussion during laboratory dissection. CONCLUSIONS: Asynchronous online learning for anatomy lecture may be beneficial for dental students; however, a smaller dissection group accompanied by reduced peer discussion may temporarily exert negative effects on their laboratory performance at the beginning of the application. Furthermore, more dental students exhibited positive perceptions towards smaller dissection groups. These findings could illuminate the learning condition of dental students in anatomy education.


Assuntos
Desempenho Acadêmico , Anatomia , COVID-19 , Educação de Graduação em Medicina , Estudantes de Medicina , Humanos , Aprendizagem , Estudantes de Odontologia , Pandemias , Educação em Odontologia , Anatomia/educação , Ensino , Currículo
4.
BMC Med Educ ; 22(1): 341, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35505291

RESUMO

BACKGROUND: Registered nurses are required for high-quality healthcare. Thus, the anatomy course is essential regarding professional knowledge of the human body during the nursing training process. However, previous studies have indicated that anatomy teaching time and anatomy teachers were reduced and insufficient. Therefore, to improve the learning of practical anatomy in response to these difficulties, a bilingual National Taiwan University web-based anatomy atlas (NTU-WAA) was created as a cross-platform application and its feasibility was evaluated. METHODS: The comparison of anatomy examination scores between nursing students of two cohorts (66 from the 2018-2019 cohort, whom was without NTU-WAA application; 54 from the 2019-2020 cohort, to whom NTU-WAA was offered) and the evaluation of questionnaires collected from nursing students of the 2019-2020 cohort and 4 anatomy teachers were carried out to define the feasibility of this strategy. RESULTS: Results obtained by nursing students for the 2019-2020 cohort showed a significant increase in anatomy learning performance compared with that of the 2018-2019 cohort with reference to the laboratory midterm [2018-2019 cohort vs. 2019-2020 cohort, mean (standard deviation, SD): 77.20 (16.14) vs. 81.80 (12.03); p = 0.043], the laboratory final examination [59.68 (15.28) vs. 80.35 (13.74); p < 0.001] and the theory final examination [80.85 (10.10) vs. 84.33 (6.925); p = 0.017]. Moreover, results of the questionnaires indicated that the new bilingual cross-platform atlas was highly accepted by students and teachers. CONCLUSIONS: The NTU-WAA, a bilingual web-based atlas, was evaluated as a beneficial anatomy-learning tool that may enhance self-study of nursing students with consequent amelioration of their anatomy-related performance in both theoretical and laboratory examinations. This reflection suggests the future implementation of the bilingual web-based atlas on a large scale.


Assuntos
Estudantes de Enfermagem , Avaliação Educacional/métodos , Humanos , Internet , Aprendizagem , Inquéritos e Questionários
5.
Ann Neurol ; 91(6): 821-833, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35285061

RESUMO

OBJECTIVE: Although the microenvironment for peripheral nerve regeneration is permissive, such a mechanism is defective in diabetes, and the molecular mediators remain elusive. [Correction added on May 11, 2022, after first online publication: In the preceding sentence, "is ok" was changed to "is defective".] This study aimed to (1) investigate the relationship between skin innervation and collagen pathology in diabetic neuropathy and to (2) clarify the molecular alterations that occur in response to hyperglycemia and their effects on axon regeneration. METHODS: We addressed this issue using two complementary systems: (1) human skin from patients with diabetic neuropathy and to (2) a coculture model of human dermal fibroblasts (HDFs) with rat dorsal root ganglia neurons in the context of intrinsic neuronal factor and extrinsic microenvironmental collagen and its biosynthetic pathways. RESULTS: In diabetic neuropathy, the skin innervation of intraepidermal nerve fiber density (IENFd), a measure of sensory nerve degeneration, was reduced with similar expression of a growth associated protein 43, a marker of nerve regeneration. In contrast, the content and packing of collagen in the diabetic skin became more rigid than the control skin. Sec31a, a protein that regulates the collagen biosynthetic pathway, was upregulated and inversely correlated with IENFd. In the cell model, activated HDFs exposed to high-glucose medium enhanced the expression of Sec31a and collagen I through the activation of transforming growth factor ß, a profibrotic molecule. Sec31a upregulation impaired neurite outgrowth. This effect was reversed by silencing Sec31a expression and neurite outgrowth was resumed. INTERPRETATION: The current study provides evidence that Sec31a plays a key role in inhibiting nerve regeneration in diabetic neuropathy. ANN NEUROL 2022;91:821-833.


Assuntos
Diabetes Mellitus Experimental , Neuropatias Diabéticas , Animais , Axônios/patologia , Diabetes Mellitus Experimental/patologia , Neuropatias Diabéticas/patologia , Gânglios Espinais/patologia , Humanos , Regeneração Nervosa , Ratos , Pele/patologia
6.
Anat Sci Educ ; 15(3): 476-492, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35291048

RESUMO

Due to the Covid-19 pandemic, National Taiwan University anatomy teachers adopted asynchronous online video teaching and reduced the size of anatomy laboratory groups in April 2020. The aim of this study was to investigate the impact of these changes on medical students' learning. Before Covid-19, the performance of the 2019-2020 cohort was significantly better than that of the 2018-2019 cohort. However, the implementation of modified teaching strategies significantly lowered the laboratory midterm score of the 2019-2020 cohort in the second semester. Conversely, the final laboratory examination score of the 2019-2020 cohort was significantly higher than that of the 2018-2019 cohort. Through correlation analysis, lecture and laboratory examination scores were highly correlated. Additionally, the difference in lecture and laboratory z-scores between two cohorts, the Likert scale survey and free-text feedback of the 2019-2020 cohort, were conducted to show the impact of modified teaching strategies. There were several important findings in this study. First, the change in teaching strategies may temporarily negatively influence medical students to learn anatomy. Besides, analyzing the performance of laboratory assessments could be a complementary strategy to evaluate online assessments. Applying lecture examination scores to predict laboratory performance was a feasible way to identify students who may have difficulty in learning practical dissection. Finally, reducing group size together with reduced peer discussion may have a negative effect on learning cadaver dissection for students with low academic performance. These findings should be taken into consideration when anatomy teachers apply new teaching strategies in anatomy courses.


Assuntos
Anatomia , COVID-19 , Estudantes de Medicina , Anatomia/educação , Cadáver , Avaliação Educacional , Humanos , Pandemias , Ensino
7.
J Epidemiol ; 31(9): 503-510, 2021 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-32741854

RESUMO

BACKGROUND: To investigate all-cause and cause-specific mortality in Taiwanese patients with type 1 diabetes. METHODS: A cohort of 17,203 patients with type 1 diabetes were identified from Taiwan's National Health Insurance claims in the period of 1998-2014. Person-years were accumulated for each individual from date of type 1 diabetes registration to date of death or the last day of 2014. Age, sex, and calendar year standardized mortality ratios (SMRs) were calculated with reference to the general population. RESULTS: In up to 17 years of follow-up, 4,916 patients died from 182,523 person-years. Diabetes (30.15%), cancer (20.48%), circulatory diseases (13.14%), and renal diseases (11.45%) were the leading underlying causes of death. Mortality rate (26.93 per 1,000 person-years) from type 1 diabetes in Taiwan was high, the cause of death with the highest mortality rate was diabetes (8.12 per 1,000 person-years), followed by cancer (5.52 per 1,000 person-years), and circulatory diseases (3.54 per 1,000 person-years). The all-cause SMR was significantly elevated at 4.16 (95% confidence interval, 4.04-4.28), with a greater all-cause SMR noted in females than in males (4.62 vs 3.79). The cause-specific SMR was highly elevated for diabetes (SMR, 16.45), followed by renal disease (SMR, 14.48), chronic hepatitis and liver cirrhosis (SMR, 4.91) and infection (SMR, 4.59). All-cause SMRs were also significantly increased for all ages, with the greatest figure noted for 15-24 years (SMR, 8.46). CONCLUSIONS: Type 1 diabetes in both genders and all ages was associated with significantly elevated SMRs for all-cause and mostly for diabetes per se and renal disease.


Assuntos
Diabetes Mellitus Tipo 1/mortalidade , Adolescente , Adulto , Causas de Morte/tendências , Criança , Pré-Escolar , Estudos de Coortes , Diabetes Mellitus Tipo 1/terapia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Mortalidade/tendências , Taiwan/epidemiologia , Adulto Jovem
8.
J Diabetes ; 9(6): 622-627, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27485041

RESUMO

BACKGROUND: Population-based data for diabetic hand syndrome (DHS) are limited. The aim of the present epidemiological study was to estimate the overall and cause-specific prevalence and rate ratio (RR) of DHS in patients with diabetes. METHODS: The present study was a cross-sectional study based on a random sample of 57 093 diabetics and matched controls, both identified from Taiwan National Health Insurance claims in 2010. The DHS analyzed in the present study included carpal tunnel syndrome (CTS), stenosing flexor tenosynovitis (SFT), limited joint mobility (LJM), and Dupuytren's disease (DD). RESULTS: The prevalence of overall DHS was estimated at 2472 per 105 for the diabetics, compared with 1641 per 105 for the controls, representing a prevalence RR of 1.51 (95 % confidence interval [CI] 1.39-1.64). Stratified analyses further revealed that the significantly increased prevalence of overall DHS was more evident in females than males (1.59 vs 1.36) and was only noted in diabetics aged ≥35 years. Cause-specific analysis suggested that patients with diabetes had the highest prevalence of CTS (1244 per 105 ), followed by SFT (1209 per 105 ), LJM (39 per 105 ), and DD (6 per 105 ). In addition, diabetes was only significantly associated with CTS (RR 1.34; 95 % CI 1.20-1.51) and SFT (1.74; 95 % CI 1.54-1.97). CONCLUSION: The prevalence of overall and certain cause-specific DHS was significantly elevated in patients with diabetes in Taiwan.


Assuntos
Síndrome do Túnel Carpal/epidemiologia , Diabetes Mellitus/epidemiologia , Contratura de Dupuytren/epidemiologia , Encarceramento do Tendão/epidemiologia , Adulto , Fatores Etários , Idoso , Comorbidade , Estudos Transversais , Feminino , Geografia , Humanos , Masculino , Pessoa de Meia-Idade , Vigilância da População/métodos , Prevalência , Fatores de Risco , Fatores Sexuais , Taiwan/epidemiologia
9.
Sci Rep ; 6: 35612, 2016 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-27748450

RESUMO

Delivering gene constructs into the dorsal root ganglia (DRG) is a powerful but challenging therapeutic strategy for sensory disorders affecting the DRG and their peripheral processes. The current delivery methods of direct intra-DRG injection and intrathecal injection have several disadvantages, including potential injury to DRG neurons and low transfection efficiency, respectively. This study aimed to develop a spinal nerve injection strategy to deliver polyethylenimine mixed with plasmid (PEI/DNA polyplexes) containing green fluorescent protein (GFP). Using this spinal nerve injection approach, PEI/DNA polyplexes were delivered to DRG neurons without nerve injury. Within one week of the delivery, GFP expression was detected in 82.8% ± 1.70% of DRG neurons, comparable to the levels obtained by intra-DRG injection (81.3% ± 5.1%, p = 0.82) but much higher than those obtained by intrathecal injection. The degree of GFP expression by neurofilament(+) and peripherin(+) DRG neurons was similar. The safety of this approach was documented by the absence of injury marker expression, including activation transcription factor 3 and ionized calcium binding adaptor molecule 1 for neurons and glia, respectively, as well as the absence of behavioral changes. These results demonstrated the efficacy and safety of delivering PEI/DNA polyplexes to DRG neurons via spinal nerve injection.


Assuntos
Gânglios Espinais/metabolismo , Expressão Gênica , Vetores Genéticos/administração & dosagem , Proteínas de Fluorescência Verde/metabolismo , Injeções Espinhais/métodos , Animais , Técnicas de Transferência de Genes , Proteínas de Fluorescência Verde/genética , Plasmídeos/administração & dosagem , Polietilenoimina , Ratos , Ratos Sprague-Dawley , Nervos Espinhais
10.
Asian Nurs Res (Korean Soc Nurs Sci) ; 10(4): 289-294, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28057316

RESUMO

PURPOSE: The purpose of this study was to understand the situation of diabetes patients receiving examinations for diabetes complications and to explore the factors influencing their intention to receive examinations for diabetes complications. METHODS: A cross-sectional study was performed that included 251 diabetes patients who visited outpatient clinics in Southern Taiwan. A survey using a self-administered questionnaire was conducted from October 2015 to January 2016. The questionnaire included items on demographic characteristics, perceived susceptibility to diabetes complications, perceived seriousness of diabetes complications, perceived benefits of taking action to receive diabetes complication examinations, perceived barriers to taking action to receive diabetes complication examinations, and the intention to receive diabetes complication examinations. The data were analyzed using regression analysis. RESULTS: The percentage of participants who received fundus, foot, and kidney examinations was 67.7%, 61.4%, and 73.3%, respectively. Every point increase on the perceived barriers to taking action to receive diabetes complication examinations scale increased the intention to receive a foot examination in the following year by 0.91 times (p=.002), and every point increase on the perceived susceptibility to diabetes complications scale increased the intention to receive a kidney examination in the following year by 1.19 times (p=.045). CONCLUSIONS: Nurses should shoulder the responsibility to increase patients' intention to receive examination of diabetes complications. The results of this study can be used to promote nurses' care efficacy in preventing diabetes complications. They can also provide medical institutions with information to establish prevention and control policies for diabetes complications.


Assuntos
Angiopatias Diabéticas/prevenção & controle , Nefropatias Diabéticas/prevenção & controle , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Exame Físico/psicologia , Assistência Ambulatorial/estatística & dados numéricos , Estudos Transversais , Angiopatias Diabéticas/enfermagem , Angiopatias Diabéticas/psicologia , Nefropatias Diabéticas/enfermagem , Nefropatias Diabéticas/psicologia , Suscetibilidade a Doenças/psicologia , Diagnóstico Precoce , Feminino , Humanos , Intenção , Testes de Função Renal , Masculino , Pessoa de Meia-Idade , Relações Enfermeiro-Paciente , Oftalmoscopia , Percepção , Exame Físico/enfermagem , Exame Físico/estatística & dados numéricos , Taiwan
11.
J Occup Health ; 53(2): 130-6, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21325778

RESUMO

OBJECTIVE: To compare occupational exposure to extremely-low-frequency magnetic field (ELF-MF) between dentists practicing in dental clinics and those employed in hospitals. METHODS: Thirty-two dentists who worked at clinics (n=15) and 33 dentists employed at hospital dental departments (n=7) voluntarily provided their informed consent to participate in this measurement study. The study dentists were requested to wear an ELF-MF dosimeter for some 3 h at work to determine their personal exposure. Spot measurements taken at a number of locations in each dental office were used to indicate the work environment exposure level. Additionally, ELF-MF emitted from common dental equipment was also measured. All measurements were performed with EMDEX Lite meters. RESULTS: The average environmental exposure to ELF-MF is higher in clinic dental offices than in hospital dental departments (0.55 vs. 0.15 µT, p=0.008). Personal dosimetry showed that on average, clinic dentists spent 35.71 and 19.39% of their time at exposures above 0.3 and 0.4 µT at work, respectively. The corresponding figures for hospital dentists were 19.61 and 13.92%. Additionally, ELF-MF was greater than 0.4 µT at 30 cm from all selected equipment, but the ELF-MF generally diminished as the distance from dental equipment increased. Uultraviolet air sterilization system produced 3 times as much ELF-MF as other dental equipment. CONCLUSIONS: This study suggests the possibility of over-exposure of dentists to power frequency ELF-MF. Additionally, certain dental equipment may produce ELF-MF levels greater than 0.4 µT in areas where dentists usually work when treating patients.


Assuntos
Clínicas Odontológicas , Odontólogos , Campos Eletromagnéticos , Hospitais , Exposição Ocupacional/análise , Humanos
12.
J Neuropathol Exp Neurol ; 68(12): 1269-81, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19915488

RESUMO

We assessed the effects of treatment with 4-methylcatechol (4MC), a known inducer of nerve growth factor, on peripheral nerve regeneration by analyzing cutaneous and muscular reinnervation in mice after sciatic nerve crush injury. At 3 months postinjury, the skin innervation index was significantly higher in the 4MC group than the control group (p=0.0002); there was also increased unmyelinated fiber density (p=0.0042) and unmyelinated fibers/Remak bundle (p = 0.001) in sural nerves, indicating unmyelinated nerve fiber regeneration. These changes were accompanied by increases of transcripts for nerve growth factor (p = 0.0026) and glial cell line-derived neurotrophic factor (p=0.03) in the 4MC group. In contrast, muscle innervation indices were similar in both groups and were higher than the skin innervation index (p < 0.0001). The regeneration of myelinated nerve fibers, as assessed by fiber density, diameter and g ratio analyses in sural nerves, and amplitudes of muscle action potential in sciatic nerves, was similar in both groups. Taken together, these data suggest that 4MC specifically promoted the regeneration of unmyelinated nerve fibers and reinnervation of the skin by increasing the expression of nerve growth factor and glial cell line-derived neurotrophic factor.


Assuntos
Catecóis/farmacologia , Músculo Esquelético/inervação , Regeneração Nervosa/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Pele/inervação , Potenciais de Ação/efeitos dos fármacos , Animais , Expressão Gênica/efeitos dos fármacos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos ICR , Microscopia Eletrônica de Transmissão , Músculo Esquelético/efeitos dos fármacos , Compressão Nervosa , Fibras Nervosas Mielinizadas/efeitos dos fármacos , Fibras Nervosas Mielinizadas/ultraestrutura , Fibras Nervosas Amielínicas/efeitos dos fármacos , Fibras Nervosas Amielínicas/ultraestrutura , Fator de Crescimento Neural/biossíntese , Fator de Crescimento Neural/efeitos dos fármacos , Condução Nervosa , Junção Neuromuscular/efeitos dos fármacos , Junção Neuromuscular/ultraestrutura , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Nervo Isquiático/lesões , Pele/efeitos dos fármacos
13.
J Proteome Res ; 8(2): 1004-13, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19099420

RESUMO

Liver is unique in its capability to regenerate after an injury. Liver regeneration after a 2/3 partial hepatectomy served as a classical model and is adopted frequently to study the mechanism of liver regeneration. In the present study, semiquantitative analysis of protein expression in mouse liver regeneration following partial hepatectomy was performed using an iTRAQ technique. Proteins from pre-PHx control livers and livers regenerating for 24, 48 and 72 h were extracted and inspected using 4-plex isotope labeling, followed by liquid chromatography fractionation, mass spectrometry and statistical differential analysis. A total of 827 proteins were identified in this study. There were 270 proteins for which quantitative information was available at all the time points in both biologically duplicate experiments. Among the 270 proteins, Car3, Mif, Adh1, Lactb2, Fabp5, Es31, Acaa1b and LOC100044783 were consistently down-regulated, and Mat1a, Dnpep, Pabpc1, Apoa4, Oat, Hpx, Hp and Mt1 were up-regulated by a factor of at least 1.5 from that of the controls at one time point or more. The regulation of each differential protein was also demonstrated by monitoring its time-dependent expression changes during the regenerating process. We believe this is the first report to profile the protein changes in liver regeneration utilizing the iTRAQ proteomic technique.


Assuntos
Hepatectomia , Marcação por Isótopo/métodos , Regeneração Hepática/fisiologia , Fígado/química , Análise Serial de Proteínas , Proteínas/análise , Animais , Feminino , Fígado/metabolismo , Extratos Hepáticos/química , Espectrometria de Massas/métodos , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Análise Serial de Proteínas/instrumentação , Análise Serial de Proteínas/métodos , Proteoma/análise , Reprodutibilidade dos Testes
14.
FEBS Lett ; 579(20): 4337-43, 2005 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-16061232

RESUMO

This study focused on identifying the signalling mediating the effect of magnolol on corticosterone production. Magnolol-induced corticosterone production was completely inhibited by mitogen-activated protein kinase kinase (MEK)-inhibitor PD98059, tyrosine kinase (TK)-inhibitor genistein or Janus tyrosine kinase 2 (JAK2)-inhibitor AG490, suggesting that extracellular signal-regulated kinase (ERK) and JAK2 are both involved in this signaling cascade. Further, magnolol induced the transient phosphorylation of MEK, ERK, cAMP response-element binding protein (CREB) and the expression of 32 and 30 kDa steroidogenic acute regulatory protein (StAR) in a time-dependent manner. Inhibition of TK or JAK2 activities blocked magnolol-induced phosphorylation of MEK and ERK, again supporting the upstream role of JAK2. The activation of JAK2 or MEK apparently mediated the magnolol-induced phosphorylation of CREB and the upregulation of StAR. These findings demonstrate a novel pathway for magnolol to induce the expression of StAR, which regulates the rate-limiting step in sterodiogenesis.


Assuntos
Córtex Suprarrenal/metabolismo , Compostos de Bifenilo/farmacologia , Corticosterona/biossíntese , Lignanas/farmacologia , Fosfoproteínas/metabolismo , Transdução de Sinais , Córtex Suprarrenal/efeitos dos fármacos , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Janus Quinase 2 , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/metabolismo , Ratos , Ratos Wistar
15.
Histochem Cell Biol ; 123(4-5): 429-39, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15844002

RESUMO

Magnolol stimulates adrenal steroidogenesis and induces the distributional changes of p160 and adipose differentiation-related protein (ADRP) in rat adrenal cells. This study investigated the underlying signaling mechanisms involved in these processes. Magnolol (30 microM) caused a time-dependent increase in the phosphorylation of extracellular signal-related kinase (ERK) in cultured adrenal cells. The following evidence supports a link between ERK activation and p160 translocation. First, the magnolol-induced redistribution of p160 from the lipid droplet surface to the cytosol, resulting in the decrease in the percentages of p160-positive cells, and this decrease in p160-positive cells was completely blocked by pretreatment with either of the MAPK-ERK kinase (MEK) inhibitors PD98059 or U0126. Second, magnolol did not significantly decrease total p160 protein levels but caused an increase in threonine phosphorylation of p160, which reached a maximum after 5 min of magnolol treatment, and this magnolol-induced phosphorylation of p160 was prevented by pretreatment with U0126, suggesting the involvement of ERK. In addition, magnolol decreased both ADRP immunostaining intensity at the lipid droplet surface and the percentage of ADRP-positive cells. This was further confirmed biochemically by the decrease in ADRP levels in total cell homogenates and in lipid droplet fractions. Magnolol-induced decrease in ADRP staining at the lipid droplet surface was not affected by pretreatment with PD98059 or U0126, indicating that ERK signaling was not involved in this event. Furthermore, treatment with 30 microM magnolol for 6 h resulted in about 50% decrease in ADRP protein level. Therefore, decreased protein levels of p160 and ADRP at the lipid droplet surface induced by magnolol were mediated via two different mechanisms: phosphorylation of p160 and downregulation of ADRP expression, respectively.


Assuntos
Glândulas Suprarrenais/efeitos dos fármacos , Compostos de Bifenilo/farmacologia , Lignanas/farmacologia , Proteínas de Membrana/metabolismo , Fatores de Transcrição/metabolismo , Glândulas Suprarrenais/citologia , Glândulas Suprarrenais/metabolismo , Animais , Western Blotting , Butadienos/farmacologia , Células Cultivadas , Grânulos Citoplasmáticos/metabolismo , Inibidores Enzimáticos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Feminino , Flavonoides/farmacologia , Imunofluorescência , Histona Acetiltransferases , Metabolismo dos Lipídeos , Toxinas Marinhas , Microscopia de Fluorescência , Nitrilas/farmacologia , Coativador 1 de Receptor Nuclear , Oxazóis/farmacologia , Perilipina-2 , Fosfoproteínas Fosfatases/antagonistas & inibidores , Fosforilação/efeitos dos fármacos , Transporte Proteico/efeitos dos fármacos , Piranos/farmacologia , Ratos , Ratos Wistar , Compostos de Espiro/farmacologia , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...