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1.
Curr Oncol ; 27(4): 198-203, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32905281

RESUMO

Background: Venous thromboembolism (vte) in malignancy is associated with poor outcomes. We conducted a retrospective review of vte in patients with endometrial cancer to characterize the vte incidence, identify factors that contribute to vte risk, and compare survival outcomes in patients with and without vte. Methods: A retrospective chart review identified 422 eligible patients who underwent surgery for endometrial cancer (1 January 2014 to 31 July 2016). The primary outcome was vte. Binary logistic regression identified risk factors for vte; significant risk factors were included in a multivariate analysis. Kaplan-Meier estimates are reported, and log rank tests were used to compare the Kaplan-Meier curves. Risk-adjusted estimates for overall survival based on vte were determined using a multivariate Cox proportional hazards model. Results: The incidence of vte was 6.16% overall and 0.7% within 60 days postoperatively. Non-endometrioid histology, stages 3 and 4 disease, laparotomy, and age (p < 0.1) were identified as factors associated with vte and were included in a multivariate analysis. The overall death rate in patients with vte was 42% (9% without vte): hazard ratio, 5.63; 95% confidence interval, 2.86 to 11.08; p < 0.0001. Adjusting for age, stage of disease, and histology, risk of death remained significant for patients with a vte: hazard ratio, 2.20; 95% confidence interval, 1.09 to 4.42; p = 0.0271. Conclusions: A method to identify patients with endometrial cancer who are at high risk for vte is important, given the implications of vte for patient outcomes and the frequency of endometrial cancer diagnoses. Factors identified in our study might assist in the recognition of such patients.


Assuntos
Neoplasias do Endométrio/complicações , Tromboembolia Venosa/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Endométrio/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco
2.
Anticancer Agents Med Chem ; 20(12): 1459-1468, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32208126

RESUMO

BACKGROUND: Hesperetin is a natural compound known for its cholesterol-lowering effect and a wide range of pharmacological activities. OBJECTIVES: Investigating the potential anticancer activities of Hesperetin in malignant hematolymphoid cell lines HuT78 and MJ, derived from patients with Cutaneous T-Cell Lymphomas (CTCL). METHODS: The cytotoxic effect of Hesperetin on two different CTCL cell lines, HuT78 and MJ, was assessed by MTS-based colorimetric assay. Apoptosis, cell cycle, ROS (Reactive Oxygen Species) and molecular analysis were performed using flow-cytometry and immunoblotting. RESULTS: Hesperetin-treated CTCL cells were arrested at the sub-G1 phase of cell cycle with the concomitant decrease in the expression of the cell cycle regulator protein cyclin B. In addition, the study found that the cellular treatment with Hesperetin caused an induction of apoptosis, which was independent of ROS generation. Hesperetin caused a significant decrease in the expression level of anti-apoptotic protein Bcl-xL and an increase in cleaved caspase-3 and PARP proteins in CTCL cells. Furthermore, Hesperetin treatment in CTCL cells down-regulated the expression of Notch1 and phosphorylation of STAT3 (Tyr705) and inhibited NFκBp65. CONCLUSION: This study highlights the anticancer properties of Hesperetin. Which induces apoptosis in CTCL cells via STAT3/Notch1/NFκB mediated signaling pathway, suggesting that further development of this novel class of flavonoid may contribute to new drug discovery for certain hematolymphoid malignancies.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Citrus/química , Hesperidina/farmacologia , NF-kappa B/antagonistas & inibidores , Receptor Notch1/antagonistas & inibidores , Fator de Transcrição STAT3/antagonistas & inibidores , Antineoplásicos Fitogênicos/química , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Hesperidina/química , Humanos , Estrutura Molecular , NF-kappa B/metabolismo , Receptor Notch1/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-Atividade , Células Tumorais Cultivadas
3.
Rev Epidemiol Sante Publique ; 63(2): 105-18, 2015 Apr.
Artigo em Francês | MEDLINE | ID: mdl-25840864

RESUMO

BACKGROUND: Falling is the leading cause of accidental death after 65. Fall prevention programs are effective, but they involve few seniors. This article reviewed the literature on facilitators and barriers to participate in such programs. METHODS: A literature review was conducted to identify documents in English, German and French published between 1990 and May 2012. Medline database, PsychInfo, Psychological and behavioral sciences and Francis were systematically searched, as were the bibliographies and some journals of public health, gerontology and social sciences. Of 462 documents found, 19 were selected and analyzed. RESULTS: Of the 19 articles selected, 12 were on qualitative studies and 7 on literature reviews. Among the barriers to participation in falls prevention programs, documents highlighted the perception of fall as an inevitable event, the inadequate timing of prevention intervention and material difficulties. Conversely, being referred to prevention intervention by a professional, being convinced by the social benefits of interventions and the adequacy of interventions to the needs of beneficiaries were factors facilitating the participation and compliance of the elderly. CONCLUSION: This literature review identified three major issues to consider when implementing sustainable and acceptable fall prevention programs: choice of the referring agent, and social representations of falling.


Assuntos
Acidentes por Quedas/prevenção & controle , Acessibilidade aos Serviços de Saúde , Idoso , Humanos
4.
J Matern Fetal Neonatal Med ; 28(17): 2084-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25367557

RESUMO

OBJECTIVES: To evaluate the perinatal results of infants born between 23 and 25.6 weeks of gestation. METHODS: Medical charts of all women giving birth prematurely (23-25.6 w) from January 2005 to December 2011 were retrospectively reviewed. Cases of malformed infants or deliveries elsewhere were excluded. RESULTS: 198 infants were included. Chorioamnionitis occurred in 86 (43.4%) of the whole group: 26 (86.7%) in the 23-week; 35 (53.8%) in the 24-week and 25 (24.3%) in the 25-week groups. Foetal maturation with antenatal corticosteroids was complete in 119 cases (60.1%): 4 (13.3%) in the 23-week; 35 (53.8%) in the 24-week and 80 (77.7%) in the 25-week groups. Foetal death at birth occurred in 22 cases (11%) and 61 newborns (30.8%) died in the neonatal period. Of the 106 survivors with 2 years complete follow-up, 45 infants (42.4%) did not present sequelae; 16 infants (15.1%) had severe sequelae. A 66.6% (4) of infants born at 23 weeks of gestation did not present sequelae compared with a 32.3% (11) at 24 weeks and 45.4% (30) at 25 weeks. CONCLUSIONS: The chorioamnionitis rate was higher when gestational age was lower. The foetal maturation rate was higher when gestational age was higher. A low severe sequelae rate was observed in the whole series, particularly in the 23-week group where the rate was lower than expected; however, these results could have been influenced by the small size of the 23-week group.


Assuntos
Corticosteroides/uso terapêutico , Maturidade dos Órgãos Fetais/efeitos dos fármacos , Idade Gestacional , Lactente Extremamente Prematuro , Resultado da Gravidez , Corticosteroides/administração & dosagem , Adulto , Peso ao Nascer , Corioamnionite/epidemiologia , Feminino , Morte Fetal , Seguimentos , Humanos , Recém-Nascido , Terapia Intensiva Neonatal/estatística & dados numéricos , Pulmão/embriologia , Morte Perinatal , Gravidez , Estudos Retrospectivos
5.
Phys Chem Chem Phys ; 17(5): 3326-31, 2015 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-25523824

RESUMO

Phosphine metal-organic frameworks (P-MOFs) are crystalline porous coordination polymers that contain phosphorus functional groups within their pores. We present the use of X-ray absorption spectroscopy (XAS) at the P K-edge to determine the phosphine to phosphine oxide ratio in two P-MOFs with MIL-101 topology. The phosphorus oxidation state is of particular interest as it strongly influences the coordination affinity of these materials for transition metals. This method can determine the oxidation state of phosphorus even when the material contains paramagnetic nuclei, differently from NMR spectroscopy. We observed that phosphine in LSK-15 accounts for 72 ± 4% of the total phosphorus groups and that LSK-12 contains only phosphine oxide.


Assuntos
Compostos Organometálicos/química , Fosfinas/química , Espectroscopia por Absorção de Raios X , Espectroscopia de Ressonância Magnética , Óxidos/química , Fósforo/química , Polímeros/química , Porosidade , Difração de Raios X
6.
Phys Chem Chem Phys ; 16(43): 23975-84, 2014 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-25286140

RESUMO

This communication reports the first observation of the formation of HO˙ produced under two different High energy ion beams, (18)O(8+) and (36)Ar(18+) having Linear Energy Transfers (LET) of 65 and 350 eV nm(-1) respectively, at temperatures up to 411 K. Both scavenging with various concentrations of SCN(-) and heavy-ion pulse radiolysis methods are used with an original temperature and pressure regulated optical cell. Deconvolution of kinetics is used to analyze the evolution of HO˙ track segment yields as a function of time and temperature. It takes care of involving the ionic strength effect and Arrhenius expression in the rate constants correction. The results show a fast decay of HO˙ yields in the 10(-10)-10(-8) s range which denotes an efficient reactivity of this species in the track structure of the ion beam. This effect is enhanced with the lowest LET of O(8+). Increasing the temperature also accelerates the decays for both ions. These observations are discussed in terms of temperature activation of reactions and the track structure exhibiting the formation of HO˙ in a "low LET" penumbra around the ionization tracks. HO˙ track segment yields at 100 ns, of 0.4 × 10(-7) and 0.6 × 10(-7) mol J(-1), respectively for 350 and 65 eV nm(-1), are not affected by temperature.

7.
Phys Chem Chem Phys ; 16(41): 22841-52, 2014 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-25242637

RESUMO

Solutions containing 8 and 32 wt% myoglobin are studied by means of infrared spectroscopy, as a function of temperature (290 K and lower temperatures), in the mid- and far-infrared spectral range. Moreover, ultrafast time-resolved infrared measurements are performed at ambient temperature in the O-D stretching region. The results evidence that the vibrational properties of water remain the same in these myoglobin solutions (anharmonicity, vibrational relaxation lifetime…) and in neat water. However, the collective properties of the water molecules are significantly affected by the presence of the protein: the orientational time increases, the solid-liquid transition is affected in the most concentrated solution and the dynamical transition of the protein is observed, from the point of view of water, even in the least concentrated solution, proving that the water and myoglobin dynamics are coupled.


Assuntos
Mioglobina/química , Água/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
8.
J Nutr Health Aging ; 18(4): 393-9, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24676320

RESUMO

OBJECTIVE: The aim of this study was to investigate the perception, knowledge, opinions and beliefs about AD in the French population to improve care for patients with Alzheimer's disease. DESIGN: A cross-sectional telephone survey in 2008. SETTING: French "Alzheimer Plan 2008-2012". PARTICIPANTS: 2013 respondents, representative of the French population. MEASUREMENTS: The respondents answered a questionnaire in which they were presented with a series of attitudinal statements about health in general and AD. RESULTS: Main results are summarized as followed: (a) Respondents think that AD can be devastating for a family (93%). This devastating feeling prevails in the population >75 years old and in people who know patient with AD. (b) General population has a reasonable knowledge about AD, but is still unable to recognize early stages: 95% of respondents considered that difficulties to manage administrative papers and find their way back home suggest early AD. (c) 91% of the population would like to know the diagnosis if they had AD. (d) 38% of the population know or have known at least one patient within their social circle. People think that the care of AD's patient can be better but they trust in the French government to improve it. CONCLUSION: General representation of AD is changing in a positive way and, even though AD is perceived as a calamity, people are confident that solutions will be found in the future.


Assuntos
Doença de Alzheimer/terapia , Atitude Frente a Saúde , Opinião Pública , Adolescente , Adulto , Idoso , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/psicologia , Atitude Frente a Saúde/etnologia , Estudos Transversais , Feminino , França , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Telefone , Adulto Jovem
9.
J Phys Chem A ; 117(35): 8368-76, 2013 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-23924171

RESUMO

Sulfur K-edge X-ray absorption spectroscopy (XAS) has been used to distinguish between aqueous and solid sulfates and to investigate changes in their speciation. Data have been collected for tetrahedrally coordinated S in K2SO4 and KHSO4 solids and aqueous solutions. With a first qualitative analysis of the X-ray absorption near-edge structure (XANES) spectra, it has been observed that those for solids are much more structured and distinguishable from those of aqueous solutions. The protonation state has a strong effect on the white line of sulfates and has been assigned to the different charge delocalization in the samples, the effect of the solvating water molecules and multiple scattering effects. In the extended X-ray absorption fine structure (EXAFS) spectra, the backscattering from the first O shell dominated the EXAFS fine structure function, χ(k), but the nonlinear multiple scattering contributions occurring in the first coordination shell are significant and must be considered in the EXAFS analysis. The intensity of these contributions strongly depend on the symmetry of the system. For a distorted tetrahedron, the intensity of the multiple scattering contributions is less than that found in a regular tetrahedron. The FEFF code has been used to model the contributions of the multiple-scattering processes. The observed experimental evidence in the XAS data can be used to distinguish between sulfates in solids and liquids. This is applicable to many chemical, geochemical, and biological systems.

10.
Phys Chem Chem Phys ; 13(39): 17658-66, 2011 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-21909507

RESUMO

The infrared spectra of water confined in well controlled pore glasses were recorded as a function of the pore size ranging from 8 to 320 nm and in the 30-4000 cm(-1) spectral range using the ATR technique. The experiments prove that even in the large pores, the water network is significantly perturbed. The energy of the connectivity (or hindered translation) band (around 150 cm(-1)) is found to increase when the pore size decreases, indicating that confinement increases the H-bonding between neighbouring water molecules. Moreover, a drastic decrease of the FWHM of the connectivity band was observed upon confinement. This can be related to some ordering induced by the rigid walls of the pores. Furthermore, the partial filling of pores causes a significant modification to the water network, resembling heating of the trapped liquid and suggesting a role played by the water/air interface.


Assuntos
Nanoestruturas/química , Água/química , Tamanho da Partícula , Porosidade , Espectrofotometria Infravermelho , Propriedades de Superfície
11.
Anal Chem ; 79(14): 5444-8, 2007 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-17579484

RESUMO

A general strategy to localize and quantify carbon-centered radicals within proteins is described. The methodology was first exemplified on amino acids and then on a peptide. This method is applicable to any protein system regardless of size, and the site of hydrogen abstraction by *OH on all residues within proteins is easily and accurately detected.


Assuntos
Aminoácidos/química , Carbono/análise , Proteínas/química , Animais , Radicais Livres/análise , Peptídeos/química , Trítio/análise
12.
Biochim Biophys Acta ; 1764(2): 211-6, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16337234

RESUMO

We used small-angle neutron scattering to study the effects of the high hydrostatic pressure on the structure of beta-lactoglobulin. Experiments were carried out at pH 7 on the dimeric form of the protein in a pressure range going from 50 MPa to 300 MPa. These measurements allow the protein size and the interactions between macromolecules to be studied during the application of pressure. Increasing pressure up to 150 MPa leads to a swollen state of the protein that gives rise to an increase of the radius of gyration by about 7%. Within this pressure range, we also show that the interaction between macromolecules weakens although it remains repulsive. The measurements show an aggregation process occurring above 150 MPa. From the spectra analysis, it appears that the aggregation occurs mainly by association of the dimeric units.


Assuntos
Lactoglobulinas/química , Animais , Bovinos , Dimerização , Concentração de Íons de Hidrogênio , Pressão Hidrostática , Difração de Nêutrons , Dobramento de Proteína , Espalhamento de Radiação
13.
Z Gerontol Geriatr ; 38(3): 203-9, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15965795

RESUMO

The impact of social relationships on the maintenance of independence over periods of 12-18 months in a group of 306 octogenarians is assessed in this study. The study is based on the results of the Swilsoo (Swiss Interdisciplinary Longitudinal Study on the Oldest Old). Participants (80-84 years old at baseline) were interviewed five times between 1994 and 1999. Independence was defined as the capacity to perform without assistance eight activities of daily living. We distinguished in our analyses kinship and friendship networks and evaluated social relationships with the help of a series of variables serving as indicators of network composition and contact frequency. Logistic regression models were used to identify the short-term effects of social relationships on independence, after controlling for sociodemographic and health-related variables; independence at a given wave of interviews was interpreted in the light of social factors measured at the previous wave. Our analyses indicate that the existence of a close friend has a significant impact on the maintenance of independence (OR=1.58, p<0.05), which is not the case with the other variables concerning network composition. Kinship contacts were also observed to have a positive impact on independence (OR=1.12, p<0.01).


Assuntos
Atividades Cotidianas , Amigos , Nível de Saúde , Relações Interpessoais , Medição de Risco/métodos , Comportamento Social , Idoso , Idoso de 80 Anos ou mais , Demografia , Escolaridade , Feminino , Humanos , Entrevistas como Assunto , Estudos Longitudinais , Masculino , Análise de Regressão , Fatores de Risco , Distribuição por Sexo , Classe Social , Estatística como Assunto , Suíça/epidemiologia
14.
Cancer Lett ; 171(1): 67-77, 2001 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-11485829

RESUMO

Astrocytomas and oligodendrogliomas are two brain tumors that follow different clinical courses. Although many of these tumors can be identified based on standard histopathological criteria, a significant percentage present notable problems in diagnosis. To identify markers that might prove useful in distinguishing glioma subtypes, we prepared and analyzed cDNA libraries for differential expression of genes in an astrocytoma (grade II), an oligodendroglioma (grade II), and a meningioma (benign). The tumor libraries were compared by sequencing randomly selected clones and tabulating the expression frequency of each gene. In addition to identifying several genes previously reported or expected to be differentially expressed among these tumors, several potential new brain tumor markers were identified and confirmed by Northern blot analysis of a panel of brain tumors. A surprising result of this analysis was the observation that several larger-sized transcripts for various genes were predominantly expressed in the oligodendroglioma tumors, when compared to the other brain tumors or in non-tumor gray matter. These findings are consistent with different pre-mRNA splicing patterns observed between oligodendrogliomas and astrocytomas. In support of this hypothesis, our screen revealed significantly higher levels of two hnRNP A1 transcripts in oligodendrogliomas. hnRNP A1 is a component of the spliceosome whose expression levels affect splice site selection in vivo. The preferential expression of larger-sized transcripts for several genes in oligodendrogliomas may be useful for distinguishing astrocytic and oligodendroglial gliomas.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias Encefálicas/genética , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica , Glioma/classificação , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B , Oligodendroglioma/genética , Técnica de Subtração , Astrocitoma/genética , Northern Blotting , DNA Complementar/genética , Biblioteca Gênica , Glioma/genética , Ribonucleoproteína Nuclear Heterogênea A1 , Ribonucleoproteínas Nucleares Heterogêneas , Humanos , Peso Molecular , Splicing de RNA/genética , RNA Mensageiro/genética , RNA Neoplásico/genética , Ribonucleoproteínas/genética , Análise de Sequência de DNA , Spliceossomos/metabolismo
15.
Am J Physiol Endocrinol Metab ; 281(2): E289-97, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11440905

RESUMO

Murine adenocarcinoma 16 (MAC16) tumors and cell lines induce cachexia in NMRI nude mice, whereas histologically similar MAC13 tumors do not. After confirming these findings in BALB/c nude mice, we demonstrated that this tissue wasting was not related to decreased food intake or increased total body oxidative metabolism. Previous studies have suggested that MAC16's cachexigenic properties may involve the production of tumor-specific factors. We therefore screened for genes having increased expression in the MAC16 compared with the MAC13 cell line by performing hybridization to a murine cDNA expression array, by generation and comparison of cDNA libraries from each cell line, and by PCR-based subtractive hybridization. Northern blot hybridization was performed to confirm differences in transcript expression. Transcripts encoding insulin-like growth factor binding protein-4, cathepsin B, ferritin light and heavy chain, endogenous long-terminal repeat sequences, and a viral envelope glycoprotein demonstrated increased expression in the MAC16 cell line. The roles of a number of these genes in known metabolic pathways identify them as potential participants in the induction of cachexia.


Assuntos
Adenocarcinoma/genética , Caquexia/genética , Neoplasias do Colo/genética , Perfilação da Expressão Gênica , Adenocarcinoma/complicações , Animais , Northern Blotting , Caquexia/etiologia , Catepsina B/biossíntese , Catepsina B/genética , Células Clonais , Neoplasias do Colo/complicações , Modelos Animais de Doenças , Retrovirus Endógenos/genética , Ferritinas/biossíntese , Ferritinas/genética , Biblioteca Gênica , Proteína 4 de Ligação a Fator de Crescimento Semelhante à Insulina/biossíntese , Proteína 4 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Transplante de Neoplasias , Hibridização de Ácido Nucleico , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , RNA Mensageiro/biossíntese , Células Tumorais Cultivadas , Regulação para Cima
16.
Ann Pharm Fr ; 58(6 Suppl): 482-7, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11148387

RESUMO

13Carbon monoxide (CO), when bound to hemoglobin, yields (13)C NMR resonances (CO-Fe resonances). 100% CO liganded tetrameric hemoglobin ((13)C-labelled CO) was prepared for (13)C-NMR observation. The information about exchange kinetics between the four subunits (2alpha and 2B), were derived by changing the temperature (in the range 275-313K) and the observation frequency (4.7T, 9.4T and 18.8T). The first results confirmed previous observations of slow exchange between free and bound (2alpha and 2B together) CO. Besides, the exchange between alpha and B subunits were found slow at the NMR timescale, even under 313K and 4.7T conditions. Furthermore, intermediate temperatures (283-303K) allowed the observation of broad unresolved lines at 9.4T, corresponding both to CSA contribution and exchange linebroadening. Finally, low temperatures (less than 277K, at 9.4T) provided four relatively broad - but clearly distinguishable lines - indicating that a slow exchange rate was reached between four Fe-CO geometries on the subunits. This also indicated that two main Fe-CO orientations were different, even between similar chains (alpha1-alpha2 and B1-B2).


Assuntos
Carboxihemoglobina/química , Isótopos de Carbono , Humanos , Ressonância Magnética Nuclear Biomolecular/métodos , Temperatura , Termodinâmica
17.
Anal Biochem ; 275(2): 156-61, 1999 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-10552899

RESUMO

As a result of the increasing size of chemical libraries, more rapid and highly sensitive strategies are needed to accelerate the process of drug discovery without increasing the cost. One means of accomplishing this is to miniaturize the assays that enter high-throughput screening (HTS). Miniaturization requires an assay design that has few steps, has a large degree of separation between the signal and background, and has a low well to well signal variation. Fluorescence polarization (FP) is an assay type that, in many cases, meets all of the above requirements. FP is a homogenous method that allows interactions between molecules to be measured directly in solution. This article demonstrates the application of FP in a miniaturized HTS format, using 1536-well plates, to measure direct binding between cyclin-dependent kinase 2/cyclin E complex (CDK2/E) and an 8-mer-peptide kinase inhibitor. The data indicate that low variability and high specificity allow rapid and precise identification of antagonist compounds affecting CDK2/E-peptide interactions.


Assuntos
Quinases relacionadas a CDC2 e CDC28 , Ciclina E/metabolismo , Quinases Ciclina-Dependentes/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Quinase 2 Dependente de Ciclina , Polarização de Fluorescência , Miniaturização , Modelos Químicos
18.
Biophys J ; 75(6): 3154-62, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9826636

RESUMO

X-ray absorption near-edge structure (XANES) spectra of ferric myoglobin from horse heart have been acquired as a function of pH (between 5.3 and 11.3). At pH = 11.3 temperature-dependent spectra (between 20 and 293 K) have been collected as well. Experimental data solve three main conformations of the Fe-heme: the first, at low pH, is related to high-spin aquomet-myoglobin (Mb+OH2). The other two, at pH 11.3, are related to hydroxymet-myoglobin (Mb+OH-), and are in thermal equilibrium, corresponding to high- and low-spin Mb+OH-. The structure of the three Fe-heme conformations has been assigned according to spin-resolved multiple scattering simulations and fitting of the XANES data. The chemical transition between Mb+OH2 and high-spin Mb+OH-, and the spin transition of Mb+OH-, are accompanied by changes of the Fe coordination sphere due to its movement toward the heme plane, coupled to an increase of the axial asymmetry.


Assuntos
Heme/química , Ferro/química , Mioglobina/química , Animais , Sítios de Ligação , Fenômenos Biofísicos , Biofísica , Cavalos , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Miocárdio/química , Conformação Proteica , Análise Espectral , Temperatura , Baleias , Raios X
19.
Eur J Biochem ; 253(3): 751-9, 1998 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-9654075

RESUMO

An artificial hemoglobin-like domain has been constructed by engineering the gene coding for the multi-domain flavohemoprotein from the bacterium Erwinia chrysanthemi. This domain was designed by molecular modelling, cloned and over-expressed in Escherichia coli. The holo-protein was obtained in large quantities after extraction from inclusion bodies and refolding in presence of alkaline hemin. The purified 140-residue domain was studied and characterized to gain new insights into the biochemical function of the recombinant domain and the biological role of this new flavohemoprotein. The structural and functional features of this domain in solution were studied using far-ultraviolet circular dichroism, resonance Raman, proton-NMR spectroscopy, flash laser photolysis and molecular modelling. The recombinant domain is shown to be folded properly and active. This hemoglobin-like domain is able to bind oxygen and carbon monoxide with very high affinity. It exhibits a rapid auto-oxidation which may explain its tight association with a flavin containing reductase domain. A functional model of this hemoglobin is discussed and compared with the X-ray structures of other hemoproteins.


Assuntos
Dickeya chrysanthemi/metabolismo , Flavoproteínas/química , Hemeproteínas/química , Hemoglobinas/química , Conformação Proteica , Dobramento de Proteína , Dicroísmo Circular , Clonagem Molecular , Escherichia coli , Flavoproteínas/biossíntese , Flavoproteínas/metabolismo , Hemeproteínas/biossíntese , Hemeproteínas/metabolismo , Espectrometria de Massas , Modelos Moleculares , Mutagênese Sítio-Dirigida , Ressonância Magnética Nuclear Biomolecular , Fotólise , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Espectrofotometria , Análise Espectral Raman
20.
Cancer Epidemiol Biomarkers Prev ; 7(6): 531-6, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9641498

RESUMO

Prostate intraepithelial neoplasia (PIN) is a purported prostate cancer precursor lesion and a candidate biomarker for efficacy assessment in prostate cancer chemoprevention trials. Loss of expression of the pi-class glutathione S-transferase enzyme GSTP1, which is associated with the hypermethylation of deoxycytidine residues in the 5'-regulatory CG island region of the GSTP1 gene, is a near-universal finding in human prostate cancer. GSTP1 expression was assessed by immunohistochemistry in 60 high-grade PIN samples adjacent to and distant from prostate adenocarcinoma. Whereas abundant enzyme polypeptide expression was evident in all normal prostatic tissues, all samples of high-grade PIN and adenocarcinoma were completely devoid of GSTP1. DNA from 10 high-grade PIN lesions was analyzed for GSTP1 CG island methylation changes using a PCR technique targeting a polymorphic (ATAAA)n repeat sequence in the promoter region of the GSTP1 gene. Somatic GSTP1 CG island methylation changes were detected in DNA from 7 of the 10 PIN lesions. Allele discrimination was possible for 5 of the 10 DNA samples: 2 of the 5 samples exhibited DNA methylation changes at both alleles; whereas 3 samples displayed no DNA methylation changes at either allele. GSTP1 CG island methylation changes were present in each of the five homozygous samples. Hypermethylation of the 5'-regulatory region of the GSTP1 gene may serve as an important molecular genetic biomarker for both prostate cancer and PIN. The finding of frequent GSTP1 methylation changes in PIN and prostate cancer supports a role for PIN lesions as a prostate cancer precursor and may provide insight to the molecular pathogenesis of prostate cancer.


Assuntos
Adenocarcinoma/enzimologia , Biomarcadores Tumorais/genética , Glutationa Transferase/genética , Neoplasia Prostática Intraepitelial/enzimologia , Neoplasias da Próstata/enzimologia , Adenocarcinoma/genética , Adenocarcinoma/patologia , Metilação de DNA , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Masculino , Reação em Cadeia da Polimerase , Neoplasia Prostática Intraepitelial/genética , Neoplasia Prostática Intraepitelial/patologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia
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