Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 472
Filtrar
4.
Pol J Pathol ; 67(2): 136-44, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27543868

RESUMO

The hedgehog pathway is known to promote proliferation of pancreatic ductal adenocarcinoma (PDA) and has been shown to restrain tumor progression. To understand how hedgehog causes these effects, we sought to carefully examine protein expression of hedgehog signaling components during different tumor stages. Genetically engineered mice, Pdx1-Cre;LSL-KrasG12D and Pdx1-Cre;LSL-KrasG12D;p53lox/+, were utilized to model distinct phases of tumorigenesis, pancreatic intraepithelial neoplasm (PanIN) and PDA. Human pancreatic specimens of intraductal papillary mucinous neoplasm (IPMN) and PDA were also employed. PanIN and IPMN lesions highly express Sonic Hedgehog, at a level that is slightly higher than that observed in PDA. GLI2 protein is also expressed in both PanIN/IPMN and PDA. Although there was no difference in the nuclear staining, the cytoplasmic GLI2 level in PDA was modest in comparison to that in PanIN/IPMN. Hedgehog interacting protein was strongly expressed in the precursors, whereas the level in PDA was significantly attenuated. There were no differences in expression of Patched1 at early and late stages. Finally, a strong correlation between Sonic Hedgehog and GLI2 staining was found in both human and murine pancreatic tumors. The results indicate that the GLI2 protein level could serve as a feasible marker of ligand-dependent hedgehog activation in pancreatic neoplasms.


Assuntos
Biomarcadores Tumorais/análise , Carcinoma Ductal Pancreático/metabolismo , Fatores de Transcrição Kruppel-Like/biossíntese , Neoplasias Pancreáticas/metabolismo , Adenocarcinoma Mucinoso/metabolismo , Adenocarcinoma Mucinoso/patologia , Adenocarcinoma Papilar/metabolismo , Adenocarcinoma Papilar/patologia , Idoso , Idoso de 80 Anos ou mais , Animais , Carcinoma in Situ/metabolismo , Carcinoma in Situ/patologia , Carcinoma Ductal Pancreático/patologia , Modelos Animais de Doenças , Feminino , Proteínas Hedgehog/metabolismo , Humanos , Imuno-Histoquímica , Fatores de Transcrição Kruppel-Like/análise , Ligantes , Masculino , Camundongos , Camundongos Transgênicos , Pessoa de Meia-Idade , Neoplasias Pancreáticas/patologia , Proteína Gli2 com Dedos de Zinco , Neoplasias Pancreáticas
5.
Phys Rev Lett ; 115(21): 215004, 2015 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-26636857

RESUMO

Electron and ion heating characteristics during merging reconnection start-up on the MAST spherical tokamak have been revealed in detail using a 130 channel yttrium aluminum garnet (YAG) and a 300 channel Ruby-Thomson scattering system and a new 32 chord ion Doppler tomography diagnostic. Detailed 2D profile measurements of electron and ion temperature together with electron density have been achieved for the first time and it is found that electron temperature forms a highly localized hot spot at the X point and ion temperature globally increases downstream. For the push merging experiment when the guide field is more than 3 times the reconnecting field, a thick layer of a closed flux surface form by the reconnected field sustains the temperature profile for longer than the electron and ion energy relaxation time ~4-10 ms, both characteristic profiles finally forming a triple peak structure at the X point and downstream. An increase in the toroidal guide field results in a more peaked electron temperature profile at the X point, and also produces higher ion temperatures at this point, but the ion temperature profile in the downstream region is unaffected.

6.
Neuroscience ; 300: 474-92, 2015 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-26026679

RESUMO

This functional magnetic resonance imaging (fMRI) study investigated the brain regions underlying language task performance in adult second language (L2) learners. Specifically, we identified brain regions where the level of activation was associated with L2 fluency levels. Thirty Japanese-speaking adults participated in the study. All participants were L2 learners of English and had achieved varying levels of fluency, as determined by a standardized L2 English proficiency test, the Versant English Test (Pearson Education Inc., 2011). When participants performed the oral sentence building task from the production tasks administered, the dorsal part of the left inferior frontal gyrus (dIFG) showed activation patterns that differed depending on the L2 fluency levels: The more fluent the participants were, the more dIFG activation decreased. This decreased activation of the dIFG might reflect the increased automaticity of a syntactic building process. In contrast, when participants performed an oral story comprehension task, the left posterior superior temporal gyrus (pSTG) showed increased activation with higher fluency levels. This suggests that the learners with higher L2 fluency were actively engaged in post-syntactic integration processing supported by the left pSTG. These data imply that L2 fluency predicts neural resource allocation during language comprehension tasks as well as in production tasks. This study sheds light on the neural underpinnings of L2 learning by identifying the brain regions recruited during different language tasks across different modalities (production vs. comprehension).


Assuntos
Encéfalo/fisiologia , Compreensão/fisiologia , Multilinguismo , Percepção da Fala/fisiologia , Fala/fisiologia , Adolescente , Adulto , Mapeamento Encefálico , Feminino , Humanos , Testes de Linguagem , Aprendizagem/fisiologia , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Leitura , Adulto Jovem
7.
Oncogene ; 33(40): 4847-56, 2014 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-24166503

RESUMO

It is well known that microRNAs (miRs) are abnormally expressed in various cancers and target the messenger RNAs (mRNAs) of cancer-associated genes. While (miRs) are abnormally expressed in various cancers, whether miRs directly target oncogenic proteins is unknown. The present study investigated the inhibitory effects of miR-18a on colon cancer progression, which was considered to be mediated through its direct binding and degradation of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1). An MTT assay and xenograft model demonstrated that the transfection of miR-18a induced apoptosis in SW620 cells. A binding assay revealed direct binding between miR-18a and hnRNP A1 in the cytoplasm of SW620 cells, which inhibited the oncogenic functions of hnRNP A1. A competitor RNA, which included the complementary sequence of the region of the miR-18a-hnRNP A1 binding site, repressed the effects of miR-18a on the induction of cancer cell apoptosis. In vitro single and in vivo double isotope assays demonstrated that miR-18a induced the degradation of hnRNP A1. An immunocytochemical study of hnRNP A1 and LC3-II and the inhibition of autophagy by 3-methyladenine and ATG7, p62 and BAG3 siRNA showed that miR-18a and hnRNP A1 formed a complex that was degraded through the autophagolysosomal pathway. This is the first report showing a novel function of a miR in the autophagolysosomal degradation of an oncogenic protein resulting from the creation of a complex consisting of the miR and a RNA-binding protein, which suppressed cancer progression.


Assuntos
Apoptose , Neoplasias do Colo/patologia , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , MicroRNAs/genética , Fagossomos/metabolismo , Animais , Autofagia , Sítios de Ligação , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Ribonucleoproteína Nuclear Heterogênea A1 , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Transplante de Neoplasias , Ligação Proteica , Proteólise
9.
Phys Rev Lett ; 107(18): 185001, 2011 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-22107637

RESUMO

Characteristics of the high-power reconnection heating were measured for the first time directly by two-dimensional measurements of ion and electron temperatures. While electrons are heated mainly inside the current sheet by the Ohmic heating power, ions are heated mainly by fast shock or viscosity damping of the reconnection outflow in the two downstream areas. The magnetic reconnection converts the energy of reconnecting magnetic field B(p) mostly to the ion thermal energy, indicating that the reconnection heating energy is proportional to B(p)(2).

11.
Brain Res Bull ; 79(5): 271-80, 2009 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-19480987

RESUMO

Animacy helps to identify objects as living entities. To test the hypothesis that the perception of animacy via visual motion cues is represented in the same ventral visual pathways associated with living object identification through static visual information processing, 28 normal volunteers underwent functional MRI whilst tracking the movements of a self-propelling object. The target movement was held constant between conditions, whilst the animacy was externally manipulated by the presence of "chasers", from which the target was perceived to be escaping, and by "obstacles", which were static geometric objects with which the target avoided collision. The perception of target animacy was most powerfully induced by chasers, and a proximity effect was more prominently produced by obstacles. Animacy as induced by a chaser was associated with effects in the bilateral occipital poles (OPs) and the left inferior temporal gyrus to the lateral occipital complex (LOC). The LOC showed a stronger animacy effect, relative to the proximity effect, than the OPs. The effective connectivity between the LOC and the OPs was bi-directionally enhanced by the chasers. These findings suggest that both the LOC and the OPs play important roles in the identification of animated entities through the integration of information about the relationships between objects encoded in retinotopic coordinates.


Assuntos
Encéfalo/fisiologia , Cognição/fisiologia , Percepção de Movimento/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Análise de Variância , Mapeamento Encefálico , Sinais (Psicologia) , Feminino , Humanos , Vida , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Tempo de Reação , Análise de Regressão , Adulto Jovem
12.
Neuroscience ; 160(3): 688-97, 2009 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-19285546

RESUMO

To describe the neural substrates of successful episodic long-term memory encoding, we collected functional magnetic-resonance imaging data as participants completed an arbitrary delayed auditory paired-association learning task. During the task, subjects learned predefined but hidden stimulus pairs by trial and error based on visual feedback. Delay period activity represents the retrieval of the relationship between the cue item and its candidate for associates, that is, working memory. Our hypothesis was that the neural substrates of working memory would be related to long-term memory encoding in a performance-dependent manner. Thus, inter-individual variance in performance following a fixed learning set would be associated with differing neural activations during the delay period. The number of learning trials was adjusted such that performance following completion of the learning set varied across subjects. Each trial consisted of the successive presentation of two stimuli (first stimulus and second stimulus [S2]) with a fixed delay interval, allowing extraction of sustained activity during the delay period. Sustained activities during the delay period were found in the bilateral dorsolateral prefrontal cortex, intraparietal sulcus, and left ventrolateral prefrontal cortex, as well as the premotor and pre-supplementary motor areas. The activities did not change in strength across learning, suggesting that these effects represent working memory components. The sustained activity in the ventrolateral prefrontal region was correlated with task performance. Task performance was also positively correlated with the decrement in S2/feedback-related activity during learning in the superior temporal sulcus, a region previously shown to be involved in association learning. These findings are consistent with lesion and neuroimaging studies showing that the ventrolateral prefrontal cortex plays an important role in long-term memory encoding, and raise the possibility that working memory processes interact with long-term memory formation as represented by the covariation of activity in the superior temporal sulcus and the ventrolateral prefrontal cortex.


Assuntos
Aprendizagem por Associação/fisiologia , Memória/fisiologia , Córtex Pré-Frontal/fisiologia , Estimulação Acústica , Adulto , Análise de Variância , Encéfalo/fisiologia , Mapeamento Encefálico , Retroalimentação Psicológica , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Memória de Curto Prazo/fisiologia , Estimulação Luminosa , Tempo de Reação , Espectrografia do Som , Adulto Jovem
13.
Kyobu Geka ; 61(12): 1023-5, 2008 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-19048900

RESUMO

After the chest wall resection, its reconstruction is often needed. A 45-year-old male lung adenocarcinoma patient with chest wall invasion underwent upper lobectomy of the right lung with partial resection of 4-6th ribs. The size of the removed chest wall was 11 x 6.5 cm. We reconstructed the chest wall with Bard Composix E/X Mesh. This prosthesis is consisted of a polypropylene mesh and an expanded polytetrafluoroethylene sheet This material is seems to be useful in the reconstruction of chest wall in both preventing pulmonary adhesion and enabling good wound healing.


Assuntos
Próteses e Implantes , Toracoplastia/instrumentação , Adenocarcinoma/cirurgia , Humanos , Neoplasias Pulmonares/cirurgia , Masculino , Pessoa de Meia-Idade , Polipropilenos , Politetrafluoretileno
14.
AJNR Am J Neuroradiol ; 29(6): 1159-63, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18356470

RESUMO

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) was introduced as a good technique to evaluate structural abnormalities in the white matter. In this study, we used DTI to examine anisotropic changes of the pyramidal tracts displaced by chronic subdural hematoma (CSDH). MATERIALS AND METHODS: Twenty-six patients with unilateral CSDH underwent DTI before and after surgery. We measured fractional anisotropy (FA) values in pyramidal tracts of bilateral cerebral peduncles and calculated the ratio of the FA value on the lesion side to that on the contralateral side (FA ratio) and compared the ratios with motor weakness. Moreover, the relationships between FA ratios and clinical factors such as age, sex, midline shift, interval from trauma, and hematoma attenuation on CT were evaluated. RESULTS: FA values of pyramidal tracts on the lesion side were significantly lower than those on the contralateral side (0.66 +/- 0.07 versus 0.74 +/- 0.05, P < .0001). The FA ratio was correlated to the severity of motor weakness (r(2) = 0.32, P = .002). FA ratios after surgery improved significantly compared with those before surgery (0.96 +/- 0.08 versus 0.89 +/- 0.07, P = .0004). Intervals from trauma and the midline shift were significantly associated with decreased FA ratios (P = .0008 and P = .037). CONCLUSIONS: In patients with CSDH, a reversible decrease of FA in the affected pyramidal tract on DTI was correlated to motor weakness. These anisotropic changes were considered to be caused by a reversible distortion of neuron fibers and vasogenic edema due to the hematoma.


Assuntos
Imagem de Difusão por Ressonância Magnética/métodos , Hematoma Subdural Crônico/patologia , Interpretação de Imagem Assistida por Computador/métodos , Tratos Piramidais/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anisotropia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Estatística como Assunto
15.
Curr Biol ; 17(21): 1896-902, 2007 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-17964167

RESUMO

In healthy humans, the two cerebral hemispheres show functional specialization to a degree unmatched in other animals, and such strong hemispheric specialization contributes to unimanual skill acquisition [1, 2]. When most humans learn a new motor skill with one hand, this process results in performance improvements in the opposite hand as well [3-6]. Despite the obvious adaptive advantage of such intermanual transfer, there is no direct evidence identifying the neural substrates of this form of skill acquisition [7-9]. Here, we used functional magnetic resonance imaging (fMRI) to study brain regions activated during intermanual transfer of a learned sequence of finger movements. First, we found that the supplementary motor area (SMA) has more activity when a skill has transferred well than when it has transferred poorly. Second, we found that fMRI activity in the ventrolateral posterior thalamic nucleus correlated with successful future intermanual transfer, whereas activity in the ventrolateral anterior thalamic nucleus correlated with past intermanual transfer. Third, we found that repetitive transcranial magnetic stimulation applied over the SMA blocked intermanual transfer without affecting skill acquisition. These findings provide direct evidence for an SMA-based mechanism that supports intermanual transfer of motor-skill learning.


Assuntos
Lateralidade Funcional , Aprendizagem/fisiologia , Destreza Motora/fisiologia , Adulto , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Análise e Desempenho de Tarefas , Estimulação Magnética Transcraniana
16.
J Clin Pathol ; 60(8): 921-6, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16997920

RESUMO

BACKGROUND: Helicobacter pylori related gastric intestinal metaplasia (IM) is considered to be a precancerous lesion. AIMS: To identify the effects of H pylori eradication on K-ras mutations, cell kinetics in IM and histological changes in patients with and without gastric cancers in a one-year prospective study. METHODS: Patients included group A (n = 39), chronic gastritis, and group B (n = 53), intestinal-type early gastric cancer patients who had all undergone endoscopic mucosal resection (n = 25) or surgical resection (n = 28). K-ras codon 12 mutations in IM were examined, followed by DNA sequencing analysis. Proliferating and apoptotic cells were detected with anti-Ki-67 antibody and using the TUNEL method, respectively. RESULTS: The incidence of K-ras mutations in the cancer was only 3.8%. The mutant K-ras in IM was observed more frequently in group A (46.2%) than in group B patients (1.9%) (p<0.005). After eradication, the K-ras mutations significantly declined to 12.8% in group A (p<0.005). The mutation pattern of K-ras codon 12 before eradication was that GGT was mainly changed to AGT (50%) in group A. AGT transformation was not affected by treatment. Apoptosis in IM showed an increase after H pylori eradication in both groups (p<0.05 in group A) although no histological improvement in IM was observed. The monocyte score was significantly higher in group A than in group B (p<0.05); the score improved significantly after eradication. CONCLUSIONS: K-ras mutations in IM do not always play a role in gastric carcinogenesis but cell kinetics, especially apoptosis, in IM may contribute to it. There are early events in K-ras mutations which are influenced by H pylori infection; some mutations may also be selected by eradication. These unstable K-ras mutations in IM may be related to lymphocyte infiltration caused by H pylori infection.


Assuntos
Gastrite/patologia , Genes ras/genética , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori , Lesões Pré-Cancerosas/patologia , Neoplasias Gástricas/patologia , Apoptose/genética , Divisão Celular/genética , Doença Crônica , Códon/genética , Gastrite/genética , Gastrite/microbiologia , Humanos , Metaplasia/genética , Metaplasia/microbiologia , Metaplasia/patologia , Mutação , Neutrófilos/patologia , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/microbiologia , Estudos Prospectivos , Estômago/microbiologia , Estômago/patologia , Neoplasias Gástricas/genética , Neoplasias Gástricas/microbiologia
17.
Phytomedicine ; 13(5): 334-42, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16635741

RESUMO

Acceleration of vascular smooth muscle cell (VSMC) proliferation is closely linked to the pathogenesis of vascular diseases. We, therefore, focused on traditional Japanese herbal medicines (Kampo medicines) used to ameliorate the impairment of microcirculation or blood stasis and screened them for their ability to inhibit rat VSMC proliferation. Among them, Unsei-in was found to effectively suppress VSMC proliferation, and Coptis rhizome was the responsible constituent crude drug. The extract of Coptis rhizome inhibited VSMC proliferation with the GI(50) value of 4.4 microg/ml, which was much lower than those against the proliferation of 3Y1, dRLh-84, B16, and HeLa cells. The Coptis rhizome extract inhibited the progression of VSMC arrested at G(0)/G(1) phase from G(0)/G(1) to S phase, but not that of 3Y1 cells. Biological assay-guided fractionation revealed that an alkaloid of Coptis rhizome, coptisine, was the active ingredient in selectively preventing VSMC proliferation with GI(50) of 3.3 microM (1.2 microg/ml). When the structurally-related isoquinoline alkaloids of protoberberine class were studied for their inhibitory activities, berberine decreased the VSMC proliferation with GI(50) of 95.1 microM (35.4 microg/ml), about 30 times higher concentration than coptisine, while palmatine failed to show any activity. This study provides evidence that coptisine, an ingredient of Unsei-in, prevents VSMC proliferation selectively at lower concentrations compared with various cells or other structurally related alkaloids.


Assuntos
Berberina/análogos & derivados , Proliferação de Células/efeitos dos fármacos , Coptis/química , Medicina Kampo , Músculo Liso Vascular/efeitos dos fármacos , Animais , Berberina/farmacologia , Ciclo Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/farmacologia , Células HeLa , Humanos , Concentração Inibidora 50 , Masculino , Melanoma Experimental , Camundongos , Músculo Liso Vascular/citologia , Ratos , Ratos Sprague-Dawley , Rizoma/química
18.
Neurology ; 66(6): 935-7, 2006 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-16567718

RESUMO

The authors explored the neural substrate of visual hallucinations in dementia with Lewy bodies (DLB) by investigating changes in regional cerebral blood flow (rCBF) and psychiatric symptoms, before and after cholinesterase inhibitor treatment. Twenty subjects with DLB were treated with donepezil for a 12-week period. Hallucinations attenuated while receiving therapy, whereas occipital rCBF focally increased, suggesting that functional visual association cortex deficits may cause visual hallucinations in patients with DLB.


Assuntos
Alucinações/tratamento farmacológico , Indanos/uso terapêutico , Doença por Corpos de Lewy/tratamento farmacológico , Lobo Occipital/irrigação sanguínea , Lobo Occipital/efeitos dos fármacos , Piperidinas/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Circulação Cerebrovascular/efeitos dos fármacos , Circulação Cerebrovascular/fisiologia , Donepezila , Feminino , Alucinações/complicações , Alucinações/fisiopatologia , Humanos , Indanos/farmacologia , Doença por Corpos de Lewy/complicações , Doença por Corpos de Lewy/fisiopatologia , Masculino , Piperidinas/farmacologia , Fluxo Sanguíneo Regional/efeitos dos fármacos , Fluxo Sanguíneo Regional/fisiologia , Tomografia Computadorizada de Emissão de Fóton Único
19.
Kyobu Geka ; 58(10): 897-901, 2005 Sep.
Artigo em Japonês | MEDLINE | ID: mdl-16167817

RESUMO

A 56-year-old male was admitted for sudden chest pain followed by loss of consciousness and paraplegia. The electrocardiogram (ECG) revealed ST-elevation in leads II, III, and aVF and ST-depression in leads V3 to V6. The ultrasonic cardiography (UCG) demonstrated an intimal flap in the ascending aorta, grade III aortic regurgitation (AR), and akinesis of the posterior wall of the left ventricle. Transesophageal echocardiography directly showed dissection of the left main coronary artery. Emergency coronary artery bypass grafting (CABG) to the left anterior descending artery (LAD), obtuse marginal artery (OM) and posterolateral artery (PL) was performed using the saphenous vein. In addition, valve-sparing aortic root remodeling was performed in conjunction with replacement of the ascending aorta. The left coronary orifice was repaired and reattached to the prosthetic graft. The patient was weaned from cardiopulmonary bypass without catecholamine support. He was discharged from the hospital on foot after rehabilitation of the paraplegia. AR remains mild by UCG 3 years after surgery.


Assuntos
Aorta/cirurgia , Aneurisma Aórtico/cirurgia , Dissecção Aórtica/cirurgia , Implante de Prótese Vascular , Ponte de Artéria Coronária , Doença Aguda , Ponte Cardiopulmonar , Vasos Coronários , Emergências , Humanos , Masculino , Pessoa de Meia-Idade , Paraplegia/complicações
20.
Biochem Pharmacol ; 70(8): 1176-84, 2005 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-16140275

RESUMO

Coptisine, an isoquinoline alkaloid isolated from rhizome of Coptis japonica, inhibits proliferation of vascular smooth muscle cells (VSMCs). The aim of this study was to evaluate the action of coptisine, along with berberine (a structurally similar isoquinoline alkaloid), on progression of the cell cycle in VSMCs. Coptisine displayed antiproliferative action against VSMCs by blocking the cell cycle at G(1) and G(2)/M phases. The G(1) block was shown by inhibition of [(3)H]thymidine incorporation into VSMCs at coptisine concentrations higher than 15 microM. The mechanism underlying the G(1) arrest involved a decrease in cyclin D1 protein, although cyclin E, A, and B were not affected by coptisine treatment. The selective reduction in cyclin D1 protein was mainly attributable to accelerated proteolysis via proteasome-dependent pathway, since it was inhibited by a proteasome inhibitor, N-carbobenzoxy-L-leucinyl-L-leucinyl-L-norleucinal (MG132) and further the mRNA level of cyclin D1, protein synthesis, and mitogen-activated protein kinase (MAPK) activity remained unaltered. The mechanism underlying the G(2)/M arrest involved partial inhibition of tubulin polymerization, which was apparent at coptisine concentration of 3 microM. Berberine arrested the cell cycle at G(1) phase via a mechanism identical with coptisine, but did not cause block at G(2)/M phase. The results demonstrate that a small difference in the structure between isoquinoline alkaloids produces a big difference in activity, and that coptisine has a unique double action in arresting the cell cycle of VSMCs.


Assuntos
Ciclo Celular/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Animais , Aorta Abdominal/citologia , Aorta Abdominal/efeitos dos fármacos , Aorta Abdominal/metabolismo , Aorta Torácica/citologia , Aorta Torácica/efeitos dos fármacos , Aorta Torácica/metabolismo , Sequência de Bases , Berberina/farmacologia , Ciclina D1/metabolismo , Ciclina G , Ciclina G1 , Ciclinas/efeitos dos fármacos , Primers do DNA , Replicação do DNA/efeitos dos fármacos , Hidrólise , Masculino , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tubulina (Proteína)/efeitos dos fármacos , Tubulina (Proteína)/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...