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1.
AJNR Am J Neuroradiol ; 41(11): 2107-2113, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33004340

RESUMO

BACKGROUND AND PURPOSE: Knowledge about predictors of the outcome of flow-diverter treatment is limited. The aim of this study was to predict the angiographic occlusion status after flow-diverter treatment with computational fluid dynamics using porous media modeling for decision-making in the treatment of large wide-neck aneurysms. MATERIALS AND METHODS: A total of 27 patients treated with flow-diverter stents were retrospectively analyzed through computational fluid dynamics using pretreatment patient-specific 3D rotational angiography. These patients were classified into no-filling and contrast-filling groups based on the O'Kelly-Marotta scale. The patient characteristics, morphologic variables, and hemodynamic parameters were evaluated for understanding the outcomes of the flow-diverter treatment. RESULTS: The patient characteristics and morphologic variables were similar between the 2 groups. Flow velocity, wall shear stress, shear rate, modified aneurysmal inflow rate coefficient, and residual flow volume were significantly lower in the no-filling group. A novel parameter, called the normalized residual flow volume, was developed and defined as the residual flow volume normalized by the dome volume. The receiver operating characteristic curve analyses demonstrated that the normalized residual flow volume with an average flow velocity of ≥8.0 cm/s in the aneurysmal dome was the most effective in predicting the flow-diverter treatment outcomes. CONCLUSIONS: It was established in this study that the hemodynamic parameters could predict the angiographic occlusion status after flow-diverter treatment.


Assuntos
Embolização Terapêutica/métodos , Procedimentos Endovasculares/métodos , Hemodinâmica/fisiologia , Aneurisma Intracraniano/terapia , Modelos Neurológicos , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiografia Digital/métodos , Angiografia Cerebral/métodos , Feminino , Humanos , Hidrodinâmica , Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Aneurisma Intracraniano/fisiopatologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Stents , Resultado do Tratamento
2.
AJNR Am J Neuroradiol ; 36(11): 2140-6, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26272975

RESUMO

BACKGROUND AND PURPOSE: Rupture of the plaque fibrous cap and subsequent thrombosis are the major causes of stroke. This study evaluated morphologic features of plaque rupture in the carotid artery by using optical coherence tomography in vivo. MATERIALS AND METHODS: Thirty-six carotid plaques with high-grade stenosis were prospectively imaged by optical coherence tomography. "Plaque rupture" was defined as a plaque containing a cavity that had overlying residual fibrous caps. The fibrous cap thickness was measured at its thinnest part for both ruptured and nonruptured plaques. The distance between the minimum fibrous cap thickness site and the bifurcation point was also measured. Optical coherence tomography identified 24 ruptured and 12 nonruptured plaques. RESULTS: Multiple ruptures were observed in 9 (38%) patients: Six patients had 2 ruptures in the same plaque, 2 patients had 3 ruptures in the same plaque, and 1 patient had 5 ruptures in the same plaque. Most (84%) of the fibrous cap disruptions were identified at the plaque shoulder and near the bifurcation point (within a 4.2-mm distance). The median thinnest cap thickness was 80 µm (interquartile range, 70-100 µm), and 95% of ruptured plaques had fibrous caps of <130 µm. Receiver operating characteristic analysis revealed that a fibrous cap thickness of <130 µm was the critical threshold value for plaque rupture in the carotid artery. CONCLUSIONS: Plaque rupture was common in high-grade stenosis and was located at the shoulder of the carotid plaque close to the bifurcation. A cap thickness of <130 µm was the threshold for plaque rupture in the carotid artery.


Assuntos
Estenose das Carótidas/diagnóstico por imagem , Placa Aterosclerótica/diagnóstico por imagem , Adulto , Idoso , Artérias Carótidas/diagnóstico por imagem , Estenose das Carótidas/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placa Aterosclerótica/patologia , Curva ROC , Radiografia , Ruptura Espontânea , Tomografia de Coerência Óptica/métodos
3.
Appl Radiat Isot ; 88: 86-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24731546

RESUMO

To determine the influence of buthionine sulfoximine (BSO) on boron biodistribution after sulfhydryl borane (BSH) administration for boron neutron capture therapy, the effectiveness of the combination of BSO with sulfhydril- (BSH) and non-sulfhydril (B12H12 and BNH3) boron compounds, and the interval between BSO and BSH administration, the retention of boron in tissues have been evaluated using a 9L rat tumor model. Simultaneous administration of BSH and BSO showed significantly higher boron accumulation compared to that without BSO, however there was no difference in tissue boron level between B12H12 and BNH3 administration with BSO or without BSO. The longer interval (6h) between BSH and BSO administration related to the highest boron concentration in the brain and subcutaneous tumors compared to shorter intervals (0.5, 3h). Boron concentration in subcutaneous and brain tumors was maintained for 6 and 12h after the administration of BSH following BSO pretreatment.


Assuntos
Boroidretos/administração & dosagem , Boroidretos/farmacocinética , Terapia por Captura de Nêutron de Boro/métodos , Neoplasias Encefálicas/metabolismo , Butionina Sulfoximina/administração & dosagem , Butionina Sulfoximina/farmacocinética , Pré-Medicação/métodos , Compostos de Sulfidrila/administração & dosagem , Compostos de Sulfidrila/farmacocinética , Animais , Neoplasias Encefálicas/radioterapia , Sinergismo Farmacológico , Masculino , Taxa de Depuração Metabólica/efeitos dos fármacos , Especificidade de Órgãos/efeitos dos fármacos , Ratos , Ratos Endogâmicos F344 , Distribuição Tecidual/efeitos dos fármacos
4.
Perfusion ; 29(5): 417-24, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24317275

RESUMO

BACKGROUND: Narrowed true lumen and patent false lumen through to the terminal aorta is a high-risk condition for malperfusion syndromes (MS) in acute type-A aortic dissection. It is important to ascertain how the true and false lumens behave after surgery. PATIENTS AND METHODS: We retrospectively investigated 45 patients with this pathology. The true lumen sizes at the narrowest levels above and below the superior mesenteric artery were followed by computed tomography after surgery (0-36 months). RESULTS: Thirty-seven MS were seen in 23 patients. Hospital mortality was 8.9%. The narrowed true lumen was not enlarged in the first 6 months with a patent false lumen. The elephant trunk procedure did not improve the true lumen size. An extremely narrowed (≤3 mm) true lumen was associated with a significantly high incidence of MS and mortality. CONCLUSIONS: High incidences of MS were observed in this particular pathology. An extremely narrowed true lumen was accompanied by a high incidence of MS and mortality.


Assuntos
Aorta Abdominal , Ruptura Aórtica , Tomografia Computadorizada por Raios X , Idoso , Aorta Abdominal/diagnóstico por imagem , Aorta Abdominal/cirurgia , Ruptura Aórtica/diagnóstico por imagem , Ruptura Aórtica/mortalidade , Ruptura Aórtica/cirurgia , Aortografia , Feminino , Mortalidade Hospitalar , Humanos , Incidência , Masculino , Artéria Mesentérica Superior/diagnóstico por imagem , Artéria Mesentérica Superior/cirurgia , Pessoa de Meia-Idade , Estudos Retrospectivos , Síndrome
5.
Br J Cancer ; 101(8): 1298-306, 2009 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-19755983

RESUMO

BACKGROUND: Cytokeratins (CKs) are structural marker proteins specific for epithelial cells. However, recent studies indicate their involvement in cancer progression. METHODS: We evaluated CK18 and its filament partner, CK8 expression, by immunohistochemistry in 210 resected specimens from patients with oesophageal squamous cell carcinoma (OSCC). We also analysed the relationship between their expression and various clinicopathological parameters including prognosis. RESULTS: Neither CK18 nor CK8 was expressed in non-cancerous squamous epithelium whereas proper oesophageal glands expressed both CKs. Ninety (42.9%) tumours were CK18 positive and 85 (40.5%) CK8 positive, and the concordance rate for immunohistochemical classification for CK18 and CK8 was 82.4%. CK18 expression correlated with poorly differentiated tumours, use of neo-adjuvant chemotherapy, and advanced stage. Prognosis of patients with CK18-positive tumours was poorer than that of patients with negative OSCC (P<0.001). A similar trend was noted for CK8 expression. Multivariate analysis identified pT (P=0.020), pN number (P=0.001), and CK18 expression (P=0.004) as independent prognostic factors. CK18 expression in 83 pretreatment biopsy specimens was detected in 47 cases (56.6%) and also correlated with prognosis (P=0.045). CONCLUSION: CK18/CK8 expression correlated with progression of OSCC. The significant correlation with prognosis and stable expression in biopsy specimen suggest usefulness of CK18 in selection of treatment strategies for OSCC.


Assuntos
Biomarcadores Tumorais/análise , Carcinoma de Células Escamosas/química , Neoplasias Esofágicas/química , Queratina-18/análise , Queratina-8/análise , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Prognóstico , Taxa de Sobrevida
6.
Appl Radiat Isot ; 67(7-8 Suppl): S94-6, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19410469

RESUMO

We measured the toxicity and intracellular uptake of a newly developed boronated porphyrin EC032, and verified the fluorescence-based boron concentration measuring methods. Toxicity study showed that concentration required to produce a 50% reduction in viability (IC(50)) of EC032 was more than 0.25 mM. Fluorescence study showed the intracellular uptake of EC032 increased up until 24 h after its exposure to C6, 9L, U87, and U251 cells. There was also a linear correlation between ICP-AES and fluorescence intensity as an arbitrary unit about measurement of boron concentration. Fluorescence-based boron concentration measuring methods are very simple and useful methods, especially for screening of slight test dose of porphyrin compounds.


Assuntos
Compostos de Boro/farmacocinética , Terapia por Captura de Nêutron de Boro/métodos , Radiossensibilizantes/farmacocinética , Animais , Transporte Biológico Ativo , Compostos de Boro/química , Compostos de Boro/uso terapêutico , Compostos de Boro/toxicidade , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos da radiação , Humanos , Estrutura Molecular , Porfirinas/química , Porfirinas/farmacocinética , Porfirinas/uso terapêutico , Porfirinas/toxicidade , Radiossensibilizantes/química , Radiossensibilizantes/uso terapêutico , Radiossensibilizantes/toxicidade , Ratos
7.
Appl Radiat Isot ; 67(7-8 Suppl): S25-6, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19375927

RESUMO

Neutron capture therapy (NCT) theoretically allows an unique tumor-cell-selective high-LET particle radiotherapy. The survival benefits and safety of NCT were evaluated in 15 patients with newly diagnosed glioblastoma multiforme (GBM). Seven patients received intra-operative (IO-) NCT and eight patients received external beam (EB-) NCT. Sulfhydryl borane (BSH, 5 g/body) was administered intravenously 12 h before neutron irradiation. Additionally, p-dihydroxyboryl-phenylalanine (BPA, 250 mg/kg) was given 1 h before irradiation to the eight patients who underwent EB-NCT. EB-NCT was combined with fractionated photon irradiation. Five of 15 patients were alive at analysis for a mean follow-up time of 20.3 M. In 11 of 15 patients followed up for more than 1-year, eight (72.7%) maintained their Karnofsky performance status (KPS; 90 in 6 and 100 in 2). The median overall survival (OS) and time to magnetic resonance (MR) change (TTM) for all patients were 25.7 and 11.9 M, respectively. There was no difference in TTM between the IO-NCT (12.0 M) and EB-NCT (11.9 M) groups. The 1- and 2-year survival rates were 85.7% and 45.5%, respectively. This NCT pilot study in 15 patients with newly diagnosed GBM showed survival benefits, suggesting that the neutron capture reaction may function sufficiently to control tumors locally, and that further optimized studies in large series of patients are warranted.


Assuntos
Terapia por Captura de Nêutron de Boro/métodos , Neoplasias Encefálicas/radioterapia , Glioblastoma/radioterapia , Adulto , Idoso , Terapia por Captura de Nêutron de Boro/efeitos adversos , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/cirurgia , Protocolos Clínicos , Terapia Combinada , Glioblastoma/mortalidade , Glioblastoma/cirurgia , Humanos , Japão/epidemiologia , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Projetos Piloto , Dosagem Radioterapêutica
8.
Appl Radiat Isot ; 67(7-8 Suppl): S19-21, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19375933

RESUMO

The dose distribution and failure pattern after treatment with the external beam boron neutron capture therapy (BNCT) protocol were retrospectively analyzed. BSH (5 g/body) and BPA (250 mg/kg) based BNCT was performed in eight patients with newly diagnosed glioblastoma. The gross tumor volume (GTV) and clinical target volume (CTV)-1 were defined as the residual gadolinium-enhancing volume. CTV-2 and CTV-3 were defined as GTV plus a margin of 2 and 3 cm, respectively. As additional photon irradiation, a total X-ray dose of 30 Gy was given to the T2 high intensity area on MRI. Five of the eight patients were alive at analysis for a mean follow-up time of 20.3 months. The post-operative median survival time of the eight patients was 27.9 months (95% CI=21.0-34.8). The minimum tumor dose of GTV, CTV-2, and CTV-3 averaged 29.8+/-9.9, 15.1+/-5.4, and 12.4+/-2.9 Gy, respectively. The minimum tumor non-boron dose of GTV, CTV-2, and CTV-3 averaged 2.0+/-0.5, 1.3+/-0.3, and 1.1+/-0.2 Gy, respectively. The maximum normal brain dose, skin dose, and average brain dose were 11.4+/-1.5, 9.6+/-1.4, and 3.1+/-0.4 Gy, respectively. The mean minimum dose at the failure site in cases of in-field recurrence (IR) and out-field recurrence (OR) was 26.3+/-16.7 and 14.9 GyEq, respectively. The calculated doses at the failure site were at least equal to the tumor control doses which were previously reported. We speculate that the failure pattern was related to an inadequate distribution of boron-10. Further improvement of the microdistribution of boron compounds is expected, and may improve the tumor control by BNCT.


Assuntos
Terapia por Captura de Nêutron de Boro/métodos , Neoplasias Encefálicas/radioterapia , Glioblastoma/radioterapia , Adulto , Idoso , Boroidretos/uso terapêutico , Compostos de Boro/uso terapêutico , Neoplasias Encefálicas/mortalidade , Intervalo Livre de Doença , Feminino , Glioblastoma/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/prevenção & controle , Fenilalanina/análogos & derivados , Fenilalanina/uso terapêutico , Fótons/uso terapêutico , Dosagem Radioterapêutica , Estudos Retrospectivos , Compostos de Sulfidrila/uso terapêutico , Taxa de Sobrevida , Falha de Tratamento
9.
J Magn Reson ; 184(1): 78-84, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17046296

RESUMO

Recently, distance measurements by pulsed ESR (electron spin resonance) have been obtained using pulsed DEER (double electron-electron resonance) and DQC (double quantum coherence) in SDSL (site directed spin labeling) proteins. These methods can observe long range dipole interactions (15-80A). We applied these methods to human ubiquitin proteins. The distance between the 20th and the 35th cysteine was estimated in doubly spin labeled human ubiquitin. Pulsed DEER requires two microwave sources. However, a phase cycle is not usually required in this method. On the other hand, DQC-ESR at X-band ( approximately 9GHz) can acquire a large echo signal by using pulses of short duration and high power, but this method has an ESEEM (electron spin echo envelope modulation) problem. We used a commercial pulsed ESR spectrometer and compared these two methods.


Assuntos
Algoritmos , Cristalografia/métodos , Processamento de Sinais Assistido por Computador , Ubiquitina/química , Ubiquitina/ultraestrutura , Elétrons , Humanos , Conformação Proteica , Teoria Quântica , Marcadores de Spin
10.
Kyobu Geka ; 58(12): 1053-6, 2005 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-16281855

RESUMO

With the advent of drug eluting stents in percutaneous coronary intervention, required quality level of coronary artery bypass grafting (CABG) has been elevating. To obtain nearly perfect patency of bypass grafts, intraoperative assessment and repair of abnormal grafts are helpful. We report systematic revision and safe repair technique of arterial grafts in CABG. Side-to-side instead of commonly used end-to-side anastomosis of arterial grafts is the first step in this technique. When any abnormalities are noted in intraoperative flowmetry of a graft, the distal surgical clip is removed. Free flow of the graft is measured. A coronary probe is gently inserted into the graft and the coronary artery. Vasodilators can be injected into the graft if necessary. When direct revision of the anastomosis is indicated, the graft is cut longitudinally from the distal end up to just proximal to the anastomotic site. The shape of the anastomosis can be observed directly without removing sutures. When re-anastomosis is not indicated, the distal remnant graft tissue is folded back and utilized as a patch. Thus the graft can be easily closed without narrowing.


Assuntos
Ponte de Artéria Coronária/métodos , Vasos Coronários/cirurgia , Grau de Desobstrução Vascular , Anastomose Cirúrgica/métodos , Humanos , Monitorização Intraoperatória
11.
Kyobu Geka ; 58(7): 519-23; discussion 524-6, 2005 Jul.
Artigo em Japonês | MEDLINE | ID: mdl-16004331

RESUMO

Recently the availability of transit time flow measurement (TTFM) is reported especially in off-pump coronary artery bypass grafting (CABG). But little is known about TTFM findings in on-pump CABG. We examined the correlation between the TTFM flow pattern and the angiography findings in on-pump CABG. The subjects consisted of 52 patients who underwent on-pump CABG and angiography early after operation. In these patients, 55 internal thoracic artery (ITA), 17 gastroepiploic artery (GEA), 13 saphenous vein graft (SVG) and 41 radial artery (RA) were tested with TTFM during cardiopulmonary bypass (CPB). TTFM demonstrated a diastolic filling pattern in 53 ITA, 16 GEA, 13 SVG and 36 RA. The angiography revealed that all these grafts were perfectly patent with the exception of a GEA with a flow competition pattern. TTFM revealed an abnormal flow pattern in 2 ITA (these 2 grafts were revised during CPB and the angiography demonstrated their perfect patency), 1 GEA (to and fro pattern), 0 SVG and 5 RA (the abnormal pattern was due to graft spasm in 3 of 5, and the angiography revealed their perfect patency, however, the angiography detected stenosis in the remaining 2 grafts). The present study found that the TTFM flow pattern during CPB correlated well with the angiography findings. TTFM during CPB was useful to detect graft failure, and grafts were revised safely during CPB.


Assuntos
Ponte Cardiopulmonar , Ponte de Artéria Coronária sem Circulação Extracorpórea , Circulação Coronária/fisiologia , Doença das Coronárias/fisiopatologia , Grau de Desobstrução Vascular , Idoso , Velocidade do Fluxo Sanguíneo , Angiografia Coronária , Doença das Coronárias/cirurgia , Feminino , Humanos , Masculino , Artéria Torácica Interna/fisiopatologia , Pessoa de Meia-Idade , Artéria Radial/fisiopatologia , Veia Safena/fisiopatologia , Veia Safena/transplante
12.
Neurology ; 62(10): 1818-21, 2004 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-15159484

RESUMO

OBJECTIVE: To determine whether abnormal EKG findings could be predictive factors for death after a stroke event. METHODS: Patients with acute cerebral infarction who were 35 to 98 years old during April 1996 through November 2000 were analyzed (n = 216). A standard 12-lead EKG was recorded for each patient after acute cerebral infarction. The authors prospectively investigated the association between abnormal EKG findings and the risk for death after stroke over a 1-year period. RESULTS: Using multivariate Cox proportional hazards models, the authors found age (hazard ratio of mortality per year 1.10, 95% CI 1.06 to 1.15, p < 0.001), sex (female; hazard ratio of mortality 3.42, 95% CI 1.43 to 8.19, p = 0.006), and the presence of Q-waves in more than two leads (hazard ratio of mortality 2.75, 95% CI 1.23 to 6.14, p = 0.013) were independently associated with death after stroke. CONCLUSION: The presence of Q-waves in more than two leads could be a predictive factor for death after acute cerebral infarction.


Assuntos
Infarto Cerebral/mortalidade , Eletrocardiografia , Adulto , Idoso , Idoso de 80 Anos ou mais , Infarto Cerebral/fisiopatologia , Comorbidade , Feminino , Humanos , Tábuas de Vida , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/complicações , Isquemia Miocárdica/fisiopatologia , Modelos de Riscos Proporcionais , Estudos Prospectivos , Risco , Análise de Sobrevida
13.
J Dent Res ; 83(4): 327-32, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15044508

RESUMO

The WNT family activates an oncogenic signaling mediated through beta-catenin and is up-regulated in a variety of malignant neoplasms. The signaling translocates beta-catenin into the nucleus and stimulates carcinoma cells in the epithelial-mesenchymal transition (EMT). However, WNT expression and signaling in oral carcinomas have not been examined. The present study focused on unveiling the involvement of WNTs in oral carcinomas, and showed that carcinoma cells express 11 of 19 WNT family members by reverse-transcription/PCR. WNT-expressing carcinoma cells exhibited increased beta-catenin levels in the cytoplasmic pool and translocation to the nucleus. The activation state of signaling correlated with the expression of membrane-type 1 matrix metalloproteinase, which degrades territorial matrices in carcinoma invasion. Immunohistochemistry disclosed that WNT3 expression and nuclear localization of beta-catenin were predominant in carcinoma cells at the invasive front. These results suggest that enhanced WNT expression and signaling accelerate the progression of carcinomas via activating EMTs and local invasiveness.


Assuntos
Carcinoma de Células Escamosas/genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Neoplasias Bucais/genética , Proteínas Proto-Oncogênicas/genética , Proteínas de Peixe-Zebra , Carcinoma de Células Escamosas/metabolismo , Proteínas do Citoesqueleto/metabolismo , Humanos , Neoplasias Bucais/metabolismo , Família Multigênica , Proteínas Proto-Oncogênicas/metabolismo , Transdução de Sinais , Transativadores/metabolismo , Células Tumorais Cultivadas , Proteínas Wnt , beta Catenina
14.
Brain Dev ; 23 Suppl 1: S174-6, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11738867

RESUMO

DNA methylation is important for epigenetic regulation of genome, and it is interpreted by specific protein factors that contain a highly conserved methyl-CpG binding domain (MBD). There are at present five mammalian MBD family proteins: MBD1, MBD2, MBD3, MBD4 and MeCP2. In the family of methyl-CpG binding proteins, MBD1 is characterized by the presence of MBD, two or three cysteine-rich CXXC motifs, and the C-terminal transcriptional repression domain (TRD). In addition, MBD1 has at least five isoforms due to alternative splicing events, resulting in the existence of CXXC1, CXXC2, and CXXC3 in MBD1 isoform v1 (MBD1v1) and MBD1v2, and CXXC1 and CXXC2 in MBD1v3 and MBD1v4. MBD1v1 represses transcription preferentially from both unmethylated and hypomethylated promoters, while MBD1v3 inhibits hypermethylated but not unmethylated promoter activities. The MBD and CXXC3 sequences are responsible for the ability to bind methylated and unmethylated DNAs, respectively. MBD1 is also found to be a chromosomal protein that forms many foci within the nucleus. These findings suggest that MBD1 is a unique transcriptional regulator depending on the density of methyl-CpG pairs.


Assuntos
Cromatina/genética , Proteínas Cromossômicas não Histona , Metilação de DNA , Proteínas de Ligação a DNA/genética , Genes Reguladores/genética , Proteínas Repressoras/genética , Animais , Cromatina/metabolismo , Proteínas de Ligação a DNA/metabolismo , Genoma , Humanos , Proteína 2 de Ligação a Metil-CpG , Regiões Promotoras Genéticas/genética , Proteínas Repressoras/metabolismo , Fatores de Transcrição
15.
Bioorg Med Chem ; 9(8): 2165-9, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11504653

RESUMO

We have previously shown that RNA cleaving reagents with imidazole and primary amine groups on the 5'-end of antisense oligodeoxyribonucleotides could site-specifically cleave CpA as the target sequence of the substrate tRNA in vitro. In this study, a RNA cleaving reagent, composed of imidazole and primary amine groups on an antisense phosphorothioate oligonucleotide (Im-anti-s-ODN), was synthesized and evaluated for anti-HIV-1 activity in MT-4 cells. The sequence of the Im-anti-s-ODN was designed to be complementary to the HIV-1 gag-mRNA and to bind adjacent to the CpA cleavage site position. Im-anti-s-ODN encapsulated with the transfection reagent, DMRIE-C, had higher anti-HIV-1 activity than the unmodified antisense phosphorothioate oligonucleotide (anti-s-ODN) at a 2 microM concentration. Furthermore, the Im-anti-ODN encapsulated with DMRIE-C conferred sequence-specific inhibition.


Assuntos
Aminas/química , Fármacos Anti-HIV/síntese química , Imidazóis/química , Oligonucleotídeos Antissenso/síntese química , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Células Cultivadas , HIV-1/efeitos dos fármacos , Vírus Linfotrópico T Tipo 1 Humano/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Oligonucleotídeos Antissenso/química , Oligonucleotídeos Antissenso/farmacologia
17.
Cell ; 105(4): 487-97, 2001 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-11371345

RESUMO

In vertebrates, the biological consequences of DNA methylation are often mediated by protein factors containing conserved methyl-CpG binding domains (MBDs). Mutations in the MBD protein MeCP2 cause the neurodevelopmental disease Rett syndrome. We report here the solution structure of the MBD of the human methylation-dependent transcriptional regulator MBD1 bound to methylated DNA. DNA binding causes a loop in MBD1 to fold into a major and novel DNA binding interface. Recognition of the methyl groups and CG sequence at the methylation site is due to five highly conserved residues that form a hydrophobic patch. The structure indicates how MBD may access nucleosomal DNA without encountering steric interference from core histones, and provides a basis to interpret mutations linked to Rett syndrome in MeCP2.


Assuntos
Proteínas Cromossômicas não Histona , Metilação de DNA , Proteínas Repressoras , Acetilação , Sítios de Ligação/fisiologia , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Humanos , Proteína 2 de Ligação a Metil-CpG , Dados de Sequência Molecular , Mutagênese/fisiologia , Estrutura Terciária de Proteína , Proteínas Repressoras/química , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Síndrome de Rett/genética , Homologia de Sequência de Aminoácidos , Fatores de Transcrição
18.
Nat Struct Biol ; 8(2): 161-5, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11175907

RESUMO

Many peptide hormones elicit a wide array of physiological effects by binding to G-protein coupled receptors. We have determined the conformation of pituitary adenylate cyclase activating polypeptide, PACAP(1--21)NH(2), bound to a PACAP-specific receptor by NMR spectroscopy. Residues 3--7 form a unique beta-coil structure that is preceded by an N-terminal extended tail. This beta-coil creates a patch of hydrophobic residues that is important for receptor binding. In contrast, the C-terminal region (residues 8--21) forms an alpha-helix, similar to that in the micelle-bound PACAP. Thus, the conformational difference between PACAP in the receptor-bound and the micelle-bound states is limited to the N-terminal seven residues. This observation is consistent with the two-step ligand transportation model in which PACAP first binds to the membrane nonspecifically and then diffuses two-dimensionally in search of its receptor; a conformational change at the N-terminal region then allows specific interactions between the ligand and the receptor.


Assuntos
Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Neuropeptídeos/química , Neuropeptídeos/metabolismo , Receptores do Hormônio Hipofisário/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Ligantes , Micelas , Modelos Biológicos , Modelos Moleculares , Dados de Sequência Molecular , Neuropeptídeos/genética , Ressonância Magnética Nuclear Biomolecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Receptores do Hormônio Hipofisário/química , Deleção de Sequência/genética , Ovinos , Spodoptera
19.
Biochemistry ; 40(2): 375-86, 2001 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-11148031

RESUMO

An Escherichia coli sensor kinase, ArcB, transfers a phosphoryl group to a partner response regulator in response to anaerobic conditions. Multidimensional NMR techniques were applied to determine the solution structure of the histidine-containing phosphotransfer signaling domain of ArcB (HPt(ArcB)), which has a phosphorylation site, His717. The backbone dynamics were also investigated by analyses of the (15)N relaxation data and amide hydrogen exchange rates. Furthermore, the protonation states of the histidine imidazole rings were characterized by means of (1)H and (15)N chemical shifts at various pHs. The determined solution structure of HPt(ArcB) contains five helices and forms a four-helix bundle motif like other HPt domains. The obtained order parameters, S (2), [(1)H]-(15)N heteronuclear NOE values, and chemical exchange parameters, R(ex), showed that the alpha-helical regions of HPt(ArcB) are rigid on both picosecond to nanosecond and microsecond to millisecond time scales. On the other hand, helix D, which contains His717, exhibited low protection factors of less than 4000, indicating the presence of fluctuations on a slower time scale in helix D. These results suggest that HPt(ArcB) may undergo a small conformational change in helix D upon phosphorylation. It was also shown that the imidazole ring of His717 has a pK(a) value of 6.76, which is similar to that of a solvent-exposed histidine imidazole ring, and that a pair of deprotonated neutral tautomers are rapidly exchanged with each other. This is consistent with the solution structure of HPt(ArcB), in which the imidazole ring of His717 is exposed to the solvent.


Assuntos
Proteínas de Escherichia coli , Escherichia coli/enzimologia , Histidina/química , Proteínas de Membrana/química , Proteínas Quinases/química , Amidas , Sequência de Aminoácidos , Anaerobiose , Cristalografia por Raios X , Deutério , Histidina Quinase , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Isótopos de Nitrogênio , Ressonância Magnética Nuclear Biomolecular , Fosforilação , Conformação Proteica , Estrutura Terciária de Proteína , Transdução de Sinais , Soluções , Termodinâmica
20.
Mutat Res ; 460(3-4): 257-75, 2000 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-10946233

RESUMO

Genetic information is frequently disturbed by introduction of modified or mismatch bases into duplex DNA, and hence all organisms contain DNA repair systems to restore normal genetic information by removing such damaged bases or nucleotides and replacing them by correct ones. The understanding of this repair mechanism is a central subject in cell biology. This review focuses on the three-dimensional structural views of damaged DNA recognition by three proteins. The first protein is T4 endonuclease V (T4 endo V), which catalyzes the first reaction step of the excision repair pathway to remove pyrimidine-dimers (PD) produced within duplex DNA by UV irradiation. The crystal structure of this enzyme complexed with DNA containing a thymidine-dimer provided the first direct view of DNA lesion recognition by a repair enzyme, indicating that the DNA kink coupled with base flipping-out is important for damaged DNA recognition. The second is very short patch repair (Vsr) endonuclease, which recognizes a TG mismatch within the five base pair consensus sequence. The crystal structure of this enzyme in complex with duplex DNA containing a TG mismatch revealed a novel mismatch base pair recognition scheme, where three aromatic residues intercalate from the major groove into the DNA to strikingly deform the base pair stacking but the base flipping-out does not occur. The third is human nucleotide excision repair (NER) factor XPA, which is a major component of a large protein complex. This protein has been shown to bind preferentially to UV- or chemical carcinogen-damaged DNA. The solution structure of the XPA central domain, essential for the interaction of damaged DNA, was determined by NMR. This domain was found to be divided mainly into a (Cys)4-type zinc-finger motif subdomain for replication protein A (RPA) recognition and the carboxyl terminal subdomain responsible for DNA binding.


Assuntos
Reparo do DNA , DNA Bacteriano/química , Proteínas de Ligação a DNA/química , DNA/química , Endodesoxirribonucleases/química , Modelos Moleculares , Conformação de Ácido Nucleico , Conformação Proteica , Proteínas Virais , Motivos de Aminoácidos , Sequência de Aminoácidos , Pareamento Incorreto de Bases , Sítios de Ligação , Catálise , DNA/metabolismo , Dano ao DNA , DNA Bacteriano/metabolismo , DNA Bacteriano/efeitos da radiação , Proteínas de Ligação a DNA/metabolismo , Desoxirribonuclease (Dímero de Pirimidina) , Endodesoxirribonucleases/metabolismo , Sequências Hélice-Volta-Hélice , Humanos , Espectroscopia de Ressonância Magnética , Dados de Sequência Molecular , Ligação Proteica , Estrutura Terciária de Proteína , Dímeros de Pirimidina/química , Dímeros de Pirimidina/metabolismo , Proteína de Replicação A , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Relação Estrutura-Atividade , Especificidade por Substrato , Raios Ultravioleta , Proteína de Xeroderma Pigmentoso Grupo A
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