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1.
ESMO Open ; 9(5): 103374, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38744100

RESUMO

BACKGROUND: The inflammation-based modified Glasgow Prognostic Score (mGPS) combines serum levels of C-reactive protein and albumin and was shown to predict survival in advanced cancer. We aimed to elucidate the prognostic impact of mGPS on survival as well as its predictive value when combined with gender in unselected metastatic colorectal cancer (mCRC) patients receiving first-line chemotherapy in the randomized phase III XELAVIRI trial. PATIENTS AND METHODS: In XELAVIRI, mCRC patients were treated with either fluoropyrimidine/bevacizumab followed by additional irinotecan at first progression (sequential treatment arm; Arm A) or upfront combination of fluoropyrimidine/bevacizumab/irinotecan (intensive treatment arm; Arm B). In the present post hoc analysis, survival was evaluated with respect to the assorted mGPS categories 0, 1 or 2. Interaction between mGPS and gender was analyzed. RESULTS: Out of 421 mCRC patients treated in XELAVIRI, 362 [119 women (32.9%) and 243 men (67.1%)] were assessable. For the entire study population a significant association between mGPS and overall survival (OS) was observed [mGPS = 0: median 28.9 months, 95% confidence interval (CI) 25.9-33.6 months; mGPS = 1: median 21.4 months, 95% CI 17.6-26.1 months; mGPS = 2: median 16.8 months, 95% CI 14.3-21.2 months; P < 0.00001]. Similar results were found when comparing progression-free survival between groups. The effect of mGPS on survival did not depend on the applied treatment regimen (P = 0.21). In female patients, a trend towards longer OS was observed in Arm A versus Arm B, with this effect being clearly more pronounced in the mGPS cohort 0 (41.6 versus 25.5 months; P = 0.056). By contrast, median OS was longer in male patients with an mGPS of 1-2 treated in Arm B versus Arm A (20.8 versus 17.4 months; P = 0.022). CONCLUSION: We demonstrate the role of mGPS as an independent predictor of OS regardless of the treatment regimen in mCRC patients receiving first-line treatment. mGPS may help identify gender-specific subgroups that benefit more or less from upfront intensive therapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias Colorretais , Humanos , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Prognóstico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Inflamação/tratamento farmacológico , Inflamação/sangue , Irinotecano/uso terapêutico , Irinotecano/farmacologia , Adulto , Capecitabina/uso terapêutico , Capecitabina/farmacologia , Proteína C-Reativa/análise , Proteína C-Reativa/metabolismo , Oxaloacetatos , Bevacizumab/uso terapêutico , Bevacizumab/farmacologia , Fluoruracila/uso terapêutico , Fluoruracila/farmacologia , Biomarcadores Tumorais/sangue , Metástase Neoplásica
2.
Rev Sci Instrum ; 88(5): 053108, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28571411

RESUMO

We describe a series of microcalorimeter X-ray spectrometers designed for a broad suite of measurement applications. The chief advantage of this type of spectrometer is that it can be orders of magnitude more efficient at collecting X-rays than more traditional high-resolution spectrometers that rely on wavelength-dispersive techniques. This advantage is most useful in applications that are traditionally photon-starved and/or involve radiation-sensitive samples. Each energy-dispersive spectrometer is built around an array of several hundred transition-edge sensors (TESs). TESs are superconducting thin films that are biased into their superconducting-to-normal-metal transitions. The spectrometers share a common readout architecture and many design elements, such as a compact, 65 mK detector package, 8-column time-division-multiplexed superconducting quantum-interference device readout, and a liquid-cryogen-free cryogenic system that is a two-stage adiabatic-demagnetization refrigerator backed by a pulse-tube cryocooler. We have adapted this flexible architecture to mate to a variety of sample chambers and measurement systems that encompass a range of observing geometries. There are two different types of TES pixels employed. The first, designed for X-ray energies below 10 keV, has a best demonstrated energy resolution of 2.1 eV (full-width-at-half-maximum or FWHM) at 5.9 keV. The second, designed for X-ray energies below 2 keV, has a best demonstrated resolution of 1.0 eV (FWHM) at 500 eV. Our team has now deployed seven of these X-ray spectrometers to a variety of light sources, accelerator facilities, and laboratory-scale experiments; these seven spectrometers have already performed measurements related to their applications. Another five of these spectrometers will come online in the near future. We have applied our TES spectrometers to the following measurement applications: synchrotron-based absorption and emission spectroscopy and energy-resolved scattering; accelerator-based spectroscopy of hadronic atoms and particle-induced-emission spectroscopy; laboratory-based time-resolved absorption and emission spectroscopy with a tabletop, broadband source; and laboratory-based metrology of X-ray-emission lines. Here, we discuss the design, construction, and operation of our TES spectrometers and show first-light measurements from the various systems. Finally, because X-ray-TES technology continues to mature, we discuss improvements to array size, energy resolution, and counting speed that we anticipate in our next generation of TES-X-ray spectrometers and beyond.

3.
J Synchrotron Radiat ; 22(3): 766-75, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25931095

RESUMO

X-ray emission spectroscopy (XES) is a powerful element-selective tool to analyze the oxidation states of atoms in complex compounds, determine their electronic configuration, and identify unknown compounds in challenging environments. Until now the low efficiency of wavelength-dispersive X-ray spectrometer technology has limited the use of XES, especially in combination with weaker laboratory X-ray sources. More efficient energy-dispersive detectors have either insufficient energy resolution because of the statistical limits described by Fano or too low counting rates to be of practical use. This paper updates an approach to high-resolution X-ray emission spectroscopy that uses a microcalorimeter detector array of superconducting transition-edge sensors (TESs). TES arrays are discussed and compared with conventional methods, and shown under which circumstances they are superior. It is also shown that a TES array can be integrated into a table-top time-resolved X-ray source and a soft X-ray synchrotron beamline to perform emission spectroscopy with good chemical sensitivity over a very wide range of energies.

4.
Struct Dyn ; 2(2): 024301, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26798792

RESUMO

We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 µm FWHM x-ray spot size, containing ∼10(6) photons/s, by focusing the produced x-rays with a polycapillary optic. Since the acquisition of x-ray absorption spectra requires the averaging of measurements from >10(7) laser pulses, we also present data on the source stability, including single pulse measurements of the x-ray yield and the x-ray spectral shape. In single pulse measurements, the x-ray flux has a measured standard deviation of 8%, where the laser pointing is the main cause of variability. Further, we show that the variability in x-ray spectral shape from single pulses is low, thus justifying the combining of x-rays obtained from different laser pulses into a single spectrum. Finally, we show a static x-ray absorption spectrum of a ferrioxalate solution as detected by a microcalorimeter array. Altogether, our results demonstrate that this water-jet based plasma source is a suitable candidate for laboratory-based time-resolved x-ray absorption spectroscopy experiments.

5.
Allergy ; 69(12): 1629-38, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25130503

RESUMO

BACKGROUND: Cluster immunotherapy represents an interesting alternative to conventional up-dosing schedules because it allows achieving the maintenance dose within a shorter time interval. In this study, the efficacy and safety of cluster immunotherapy with a high polymerized allergen extract of a grass/rye pollen mixture have been evaluated in a randomized, double-blind, placebo-controlled, multicenter study. METHODS: In total, 121 patients with allergic rhinoconjunctivitis due to grass pollen were randomized 1 : 1 to verum or placebo group. A short cluster up-dosing schedule of only 1 week was applied to achieve the maintenance dose which was administered monthly during the study period of 1 year. Total combined symptom and medication score (TCS) was defined as primary outcome parameter. Secondary outcome parameters were individual symptom and medication scores, 'well days,' global improvement as well as immunological effects and nasal allergen challenge. The safety profile was evaluated based on the European academy of allergy and clinical immunology grading system. RESULTS: Significant reduction in the verum compared to the placebo group (intention-to-treat, population, verum: n = 55; placebo: n = 47) was found regarding TCS (P = 0.005), rhinoconjunctivitis total symptom score (RTSS, P = 0.006), and total rescue medication score (TRMS, P = 0.002). Additionally, secondary outcomes such as 'well days,' nasal challenge results, and increase of specific IgG4 were in favor of the active treatment. All systemic adverse reactions (0.8% of all injections in the verum group) were of mild intensity. No severe reactions related to the study medication were observed. CONCLUSION: Cluster immunotherapy with high polymerized grass pollen extracts resulted in significant clinical efficacy and has been shown to be a safe treatment for grass pollen-allergic patients.


Assuntos
Alérgenos/administração & dosagem , Alérgenos/imunologia , Dessensibilização Imunológica , Extratos Vegetais/administração & dosagem , Extratos Vegetais/imunologia , Poaceae/imunologia , Pólen/imunologia , Adolescente , Adulto , Idoso , Conjuntivite Alérgica/diagnóstico , Conjuntivite Alérgica/imunologia , Conjuntivite Alérgica/terapia , Dessensibilização Imunológica/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Poaceae/química , Pólen/química , Fatores de Risco , Resultado do Tratamento , Adulto Jovem
6.
Phys Rev Lett ; 110(13): 138302, 2013 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-23581383

RESUMO

This work presents an x-ray absorption measurement by use of ionizing radiation generated by a femtosecond pulsed laser source. The spectrometer was a microcalorimetric array whose pixels are capable of accurately measuring energies of individual radiation quanta. An isotropic continuum x-ray spectrum in the few-keV range was generated from a laser plasma source with a water-jet target. X rays were transmitted through a ferrocene powder sample to the detector, whose pixels have average photon energy resolution ΔE=3.14 eV full-width-at-half-maximum at 5.9 keV. The bond distance of ferrocene was retrieved from this first hard-x-ray absorption fine-structure spectrum collected with an energy-dispersive detector. This technique will be broadly enabling for time-resolved observations of structural dynamics in photoactive systems.

7.
J Phys Chem A ; 116(40): 9878-87, 2012 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-22970732

RESUMO

We have studied the photoinduced low spin (LS) to high spin (HS) conversion of [Fe(bipy)(3)](2+) in aqueous solution. In a laser pump/X-ray probe synchrotron setup permitting simultaneous, time-resolved X-ray diffuse scattering (XDS) and X-ray spectroscopic measurements at a 3.26 MHz repetition rate, we observed the interplay between intramolecular dynamics and the intermolecular caging solvent response with better than 100 ps time resolution. On this time scale, the initial ultrafast spin transition and the associated intramolecular geometric structure changes are long completed, as is the solvent heating due to the initial energy dissipation from the excited HS molecule. Combining information from X-ray emission spectroscopy and scattering, the excitation fraction as well as the temperature and density changes of the solvent can be closely followed on the subnanosecond time scale of the HS lifetime, allowing the detection of an ultrafast change in bulk solvent density. An analysis approach directly utilizing the spectroscopic data in the XDS analysis effectively reduces the number of free parameters, and both combined permit extraction of information about the ultrafast structural dynamics of the caging solvent, in particular, a decrease in the number of water molecules in the first solvation shell is inferred, as predicted by recent theoretical work.


Assuntos
Compostos Férricos/química , Teoria Quântica , Termodinâmica , Cinética , Processos Fotoquímicos , Espectrometria por Raios X , Fatores de Tempo , Água/química , Difração de Raios X
8.
Clin Exp Allergy ; 38(6): 987-94, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18445082

RESUMO

BACKGROUND: Cluster immunotherapy is becoming increasingly used. It allows for a rapid build up phase and the administration of higher doses of allergen in a shorter period of time. OBJECTIVES: To evaluate the effect of short-term pre-seasonal immunotherapy using a glutaraldeyde-modified allergen vaccine in reducing specific nasal hyperreactivity in nasal challenge tests. MATERIALS AND METHODS: Thirty-three patients were selected. All patients had a positive history of allergic rhinitis and skin tests to grass pollen, although most of them (72.7%) were sensitized to other allergens as well. The study was conducted outside of the pollen season and the patients did not receive any pharmacological treatment during this period of time. Two randomized groups of patients were established; Group A: 22 patients (13 females and nine males) and Group B, 11 control patients (seven females and four males). Patients in Group A received immunotherapy with a vaccine containing 50% of the wild grasses Trisetum paniceum and Dactylis glomerata. All patients underwent titrated nasal provocation tests (NPT) before and after completion of the study (2.3 and 2.8 months for Groups A and B, respectively). The administration schedule consisted of 0.1 and 0.2 mL at day 1, followed by 0.3 and 0.5 mL at day 7, 0.5 mL after 2 weeks followed by 0.5 mL monthly. A single vial was used containing an allergen concentration of 10 000 TU/mL (105 microg of total protein and 24.6 microg of Group 1 plus 5 allergens/mL). A mean of 6.5 injections were administered to Group A patients between NPTs. RESULTS: There were no significant differences between both groups at the beginning of the study (P=0.48). At the end, only Group A patients needed significant greater threshold concentrations for a positive NPT than at the beginning (P=0.002). CONCLUSIONS: A short-term cluster pre-seasonal inmunotherapy with a modified vaccine containing a mixture of grass pollen is effective as determined by an objective measure after only a mean 2.3 months of treatment.


Assuntos
Alérgenos/administração & dosagem , Dactylis/efeitos adversos , Dessensibilização Imunológica/métodos , Poaceae/efeitos adversos , Pólen/efeitos adversos , Rinite Alérgica Sazonal/terapia , Vacinas/administração & dosagem , Adulto , Alérgenos/efeitos adversos , Análise de Variância , Esquema de Medicação , Feminino , Glutaral/administração & dosagem , Humanos , Exposição por Inalação/efeitos adversos , Injeções , Masculino , Testes de Provocação Nasal , Rinite Alérgica Sazonal/diagnóstico , Rinite Alérgica Sazonal/etiologia , Testes Cutâneos , Estatísticas não Paramétricas , Vacinas/efeitos adversos
9.
J Phys Chem B ; 111(18): 4801-6, 2007 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-17474703

RESUMO

The near-surface structure of the room-temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide has been investigated as a function of temperature between 100 and 620 K. We used a combination of photoelectron spectroscopies (XPS and UPS), metastable induced electron spectroscopy (MIES), and high-resolution electron energy loss spectroscopy (HREELS). The valence band and HREELS spectra are interpreted on the basis of density functional theory (DFT) calculations. At room temperature, the most pronounced structures in the HREELS, UPS, and MIES spectra are related to the CF3 group in the anion. Spectral changes observed at 100 K are interpreted as a change of the molecular orientation at the outermost surface, when the temperature is lowered. At elevated temperatures, early volatilization, starting at 350 K, is observed under reduced pressure.


Assuntos
Imidazóis/química , Líquidos Iônicos/química , Microscopia Eletrônica/métodos , Espectroscopia de Perda de Energia de Elétrons/métodos , Sulfonamidas/química , Temperatura , Elétrons , Sensibilidade e Especificidade , Espectrofotometria/métodos , Propriedades de Superfície , Vibração , Raios X
10.
Genome ; 46(2): 235-43, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12723039

RESUMO

The near-isogenic line (NIL) TA1150 contains a 56-cM introgression from Lycopersicon chmielewskii chromosome 1 and has several interesting phenotypic characteristics including fruit with orange color, high levels of soluble solids, thick pericarp, small stem scars, and good firmness. A set of overlapping recombinant lines (subNILs) was developed and field tested to fine map the quantitative trait loci (QTL) controlling these traits. The results indicated that the solids, pericarp thickness, and firmness QTL are distinct from the color locus. Several of the QTL mapped in this study, including the soluble-solids QTL, probably correspond to QTL mapped in other wild species of tomato. However, analysis of a set of TA523 subNILs containing complementary introgressions from Lycopesicon hirsutum chromosome 1 suggests that this wild species may contain a different locus for improved soluble solids. Thus, it might be possible to combine the L. chmielewskii and L. hirsutum alleles for these loci in a single line with the potential for extremely highly soluble solids. The TA1150 subNIL TA1688 contains the smallest introgression of the solids locus (approximately 19 cM), as well as the pericarp thickness and firmness QTL, with a yield that was equivalent to two of the three control lines. Isolation of recombinant subNILs from TA1688 should break the linkage between orange color and high solids and provide a small introgressed segment for marker-assisted breeding and genetic improvement of processing tomato.


Assuntos
Mapeamento Cromossômico , Cromossomos de Plantas , Frutas/genética , Locos de Características Quantitativas , Solanum lycopersicum/genética , Alelos , Cruzamentos Genéticos , Genes de Plantas , Ligação Genética , Genótipo , Especificidade da Espécie
11.
Biol Chem ; 382(10): 1411-9, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11727824

RESUMO

The viral interleukin-10 promoter (vIL-10p), overlapping the rep* element in the Epstein-Barr virus (EBV) genome, is a promoter element active mostly in the late phase of the lytic cycle and immediately upon infection of B cells. rep* was, through transfection experiments with small plasmids, characterised as a cis element supporting oriP replicative function. In this study, in vivo protein binding and CpG methylation at rep*/vIL-10p were analysed in five cell lines that harbour strictly latent EBV genomes. Contrary to the invariably unmethylated dyad symmetry element (DS) of oriP, rep*/vIL-10p was highly methylated and showed only traces of protein binding in all examined cell lines. This result is in agreement with vIL-10p being an inactive promoter of EBV genomes, and makes it less likely that rep* functions as a replicative element of latent EBV genomes.


Assuntos
Ilhas de CpG , Metilação de DNA , DNA/metabolismo , Herpesvirus Humano 4/genética , Interleucina-10/genética , Linfócitos/virologia , Proteínas/metabolismo , Sequência de Bases , Linhagem Celular , Genoma Viral , Humanos , Linfócitos/citologia , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Replicação Viral/genética
12.
Cancer Chemother Pharmacol ; 48 Suppl 1: S41-4, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11587366

RESUMO

Intensive induction therapy in acute myeloid leukemia (AML) as in some other systemic malignancies is a strategy fundamentally different from post-remission strategies. Approaches such as consolidation treatment, prolonged maintenance, and autologous or allogeneic transplantation in first remission are directed against the minimal residual disease in which a malignant cell population has survived induction treatment and shows resistance due to special genetic or kinetic features. In contrast, induction therapy deals with naive tumor cells possibly different from their counterparts in remission in terms of their kinetic status and sensitivity. Therefore, in AML the introduction of intensification strategies into the induction phase of treatment has been suggested as a new step in addition to intensification in the postremission phase. As expected from the dose effects observed in post-remission treatment with high-dose cytarabine (AraC) or longer treatment, similar dose effects have been found in induction treatment both from the incorporation of high-dose AraC and from the double-induction strategy used in patients up to 60 years of age. As a particular effect, patients with poor-risk AML according to an unfavorable karyotype, high LDH in serum, or a delayed response show longer survival following double induction containing high-dose AraC as compared to standard-dose AraC. A corresponding dose effect in the induction treatment of patients aged 60 years and older has been found with daunorubicin 60 vs 30 mg/m2 as part of the thioguanine/ AraC/daunorubicin (TAD) regimen with the higher dosage significantly increasing the response rate and survival in these older patients who represent a poor-risk group as a whole. Thus we have been able to demonstrate both in younger and older patients that a poor prognosis can be improved by a more intensive induction therapy. High-dose AraC in induction, however, exhibits cumulative toxicity in that repeated courses containing high-dose AraC in the post-remission period lead to long-lasting aplasias of about 6 weeks. Thus after intensive induction treatment, high-dose chemotherapy in remission may be practicable using stem-cell rescue and may contribute to a further improvement in the outcome in poor-risk as well as average-risk patients with AML. These approaches are currently under investigation by the German AML Cooperative Group (AMLCG). "The more intensive the better" is certainly not the way to go in the management of AML and other systemic malignancies but some increase in intensity may be possible and better.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Leucemia Mieloide/tratamento farmacológico , Doença Aguda , Adolescente , Adulto , Fatores Etários , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Ensaios Clínicos como Assunto , Citarabina/administração & dosagem , Daunorrubicina/administração & dosagem , Relação Dose-Resposta a Droga , Humanos , Pessoa de Meia-Idade , Indução de Remissão , Tioguanina/administração & dosagem
13.
Biol Chem ; 382(4): 699-705, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11405234

RESUMO

We analysed the methylation patterns of CpG dinucleotides in a bidirectional promoter region (LRS, LMP 1 regulatory sequences) of latent Epstein-Barr virus (EBV) genomes using automated fluorescent genomic sequencing after bisulfite-induced modification of DNA. Transcripts for two latent membrane proteins, LMP 1 (a transforming protein) and LMP 2B, are initiated in this region in opposite directions. We found that B cell lines and a clone expressing LMP 1 carried EBV genomes with unmethylated or hypomethylated LRS, while highly methylated CpG dinucleotides were present at each position or at discrete sites and within hypermethylated regions in LMP 1 negative cells. Comparison of high resolution methylation maps suggests that CpG methylation-mediated direct interference with binding of nuclear factors LBF 2, 3, 7, AML1/LBF1, LBF5 and LBF6 or methylation of CpGs within an E-box sequence (where activators as well as repressors can bind) is not the major mechanism in silencing of the LMP 1 promoter. Although a role for CpG methylation within binding sites of Sp1 and 3, ATF/CRE and a sis-inducible factor (SIF) cannot be excluded, hypermethylation of LRS or regions within LRS in LMP 1 negative cells suggests a role for an indirect mechanism, via methylcytosine binding proteins, in silencing of the LMP 1 promoter.


Assuntos
DNA Viral/isolamento & purificação , Genoma Viral , Herpesvirus Humano 4/genética , Regiões Promotoras Genéticas/genética , Proteínas da Matriz Viral/genética , Ilhas de CpG/genética , Metilação de DNA , Humanos , Análise de Sequência , Latência Viral
14.
J Virol ; 75(6): 2584-96, 2001 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11222681

RESUMO

Epstein-Barr viral (EBV) latency-associated promoters Qp, Cp, and LMP1p are crucial for the regulated expression of the EBNA and LMP transcripts in dependence of the latency type. By transient transfection and in vitro binding analyses, many promoter elements and transcription factors have previously been shown to be involved in the activities of these promoters. However, the latency promoters have only partially been examined at the nucleotide level in vivo. Therefore, we undertook a comprehensive analysis of in vivo protein binding and CpG methylation patterns at these promoters in five representative cell lines and correlated the results with the known in vitro binding data and activities of these promoters from previous transfection experiments. Promoter activity inversely correlated with the methylation state of promoters, although Qp was a remarkable exception. Novel protein binding data were obtained for all promoters. For Cp, binding correlated well with promoter activity; for LMP1p and Qp, binding patterns looked similar regardless of promoter activity.


Assuntos
DNA Viral/metabolismo , Fosfatos de Dinucleosídeos/metabolismo , Herpesvirus Humano 4/genética , Regiões Promotoras Genéticas/genética , Proteínas da Matriz Viral/genética , Latência Viral , Linfoma de Burkitt , Linhagem Celular Transformada , Pegada de DNA , Metilação de DNA , DNA Viral/genética , Proteínas de Ligação a DNA/metabolismo , Regulação Viral da Expressão Gênica , Herpesvirus Humano 4/metabolismo , Humanos , Ligação Proteica , Transcrição Gênica , Células Tumorais Cultivadas , Proteínas da Matriz Viral/metabolismo , Latência Viral/genética , Latência Viral/fisiologia
15.
Phys Rev Lett ; 84(10): 2068-71, 2000 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-11017211

RESUMO

A nonparametric Bayesian approach is developed to determine quantum potentials from empirical data for quantum systems at finite temperature. The approach combines the likelihood model of quantum mechanics with a priori information on potentials implemented in the form of stochastic processes. Its specific advantages are the possibilities to deal with heterogeneous data and to express a priori information explicitly in terms of the potential of interest. A numerical solution in maximum a posteriori approximation is obtained for one-dimensional problems. As nonparametric estimates, the results depend strongly on the implemented a priori information.

16.
Phys Rev Lett ; 84(20): 4517-20, 2000 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-10990729

RESUMO

A new method is presented to reconstruct the potential of a quantum mechanical many-body system from observational data, combining a nonparametric Bayesian approach with a Hartree-Fock approximation. A priori information is implemented as a stochastic process, defined on the space of potentials. The method is computationally feasible and provides a general framework to treat inverse problems for quantum mechanical many-body systems.

17.
Proc Natl Acad Sci U S A ; 91(26): 12877-81, 1994 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-7809139

RESUMO

A variant of Lycopersion esculentum var. cerasiforme is described that deviates from the typical form of the entire species, including cultivated tomatoes, in possessing high levels (500-5000 micrograms/g of dry weight) of the steroidal alkaloid alpha-tomatine in its ripe fruits. This biotype is restricted to a tiny enclave in the valley of Río Mayo, Department San Martín, Peru. Among 88 accessions of var. cerasiforme from its present distribution in the Andes, a 90% association was found between high tomatine and bitter flavor; within the Mayo watershed, all samples from the upper drainage had bitterness and high tomatine; the frequency of both traits decreased to low levels toward the lower end. Tomatine therefore probably is the source of bitterness. Throughout L. esculentum tomatine is present at very high concentrations in earliest stages of fruit development, thereafter decreasing rapidly to midperiod, and finally diminishing gradually to near zero at maturity as a result of catabolism to biologically inert compounds, except in the variant described here. High tomatine content does not appear to affect adversely either the natives, among whom the bitter types are popular, or individuals who sampled them in this survey. Genetic determination of high tomatine in ripe fruits is totally recessive and appears to be monogenic with interaction with genes of minor effect. The prevailing pattern of glycoalkaloid synthesis and degradation in development of solanaceous fruits suggests a mechanism to protect against predation prior to ripening but to permit it afterward as a device to promote dispersal. In consideration of the nondegradative nature of the variant, its genetic determination, and very restricted geographic distribution, mutation to this form appears to be a random event of doubtful evolutionary significance.


Assuntos
Solanum lycopersicum/química , Tomatina/química , Cromatografia Gasosa , Cromatografia Gasosa-Espectrometria de Massas , Genética Populacional , Geografia , Solanum lycopersicum/genética , Solanum lycopersicum/fisiologia , Peru , Fatores de Tempo
18.
Virology ; 178(2): 606-10, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2171198

RESUMO

A monoclonal antibody (mAb 7J6) neutralizing poliovirus type 2 (PV2) and poliovirus type 1 (PV1) was obtained after immunization of BALB/c mice with infectious PV2, strain MEF-1. Preincubation of mAb 7J6 with PV1 inhibited its binding to PV2 and vice versa. Neutralization-resistant variants of PV2 and PV1 were selected. Nucleotide sequencing of the RNAs of some variants revealed mutations in the loop of amino acid residues 239 to 245 in VP2 and in the loop of amino acid residues 195 to 207 in VP3. This is the first evidence that these two loops contribute to a neutralization antigenic site (N-Ag) for poliovirus. Moreover, this new site on PV2 induced intertypic cross-neutralizing antibodies.


Assuntos
Anticorpos Monoclonais/imunologia , Variação Antigênica/imunologia , Poliovirus/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/genética , Variação Antigênica/genética , Sítios de Ligação , Ligação Competitiva , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Mutação , Testes de Neutralização , Poliovirus/genética
19.
Anal Biochem ; 130(2): 481-4, 1983 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-6683473

RESUMO

Bovine serum albumin appears to improve the specificity of Cibacron Blue F3GA in affinity chromatography of enzymes which interact with nucleotides. The action of bovine serum albumin may rest in its ability to selectively mask affinity sites in the dye, which are not specific for the nucleotide-binding region of the enzyme, while not seriously impairing binding nor its elution by nucleotides. Thus, the elution of Chlorella nitrate reductase from a Blue Sepharose chromatographic column by its coenzyme, NADH, fails, unless the column is first treated with bovine serum albumin. Such treatment also improves the recovery of some other nucleotide-binding enzymes tested.


Assuntos
Nitrato Redutases/isolamento & purificação , Soroalbumina Bovina , Triazinas , Antracenos , Sítios de Ligação , Cromatografia de Afinidade , Sefarose/análogos & derivados
20.
Nahrung ; 25(3): 271-80, 1981.
Artigo em Inglês | MEDLINE | ID: mdl-7278948

RESUMO

An isolation procedure for the 12 S rapeseed globulin is described which includes precipitation by dialysis, purification using gel chromatography on Sephadex G-200, and ion-exchange chromatography on DEAE-Sephadex A-50. The isolated globulin represents a neutral protein with an isoelectric point at pH 7.25--determined by isoelectric focusing--and a relation of the acidic to basic amino acid residues (epsilon Glu, Asp--Amide ammonia: epsilon Arg, Lys, His) of 1.0. As in other storage globulins high contents of glutamic (19%) and aspartic (10%) acid and a low content of sulphur containing amino acids are characteristic for the amino acid composition. Amongst the basic amino acids arginine has the highest percentage (7%). Opposite to results of other authors the sugar content of the globulin is low (0.5%). From the amino acid composition an average hydrophobicity according to Bigelow was calculated which amounts to be 1041 cal/res. (4.36 kJ/res.).


Assuntos
Brassica/análise , Globulinas/isolamento & purificação , Proteínas de Plantas/isolamento & purificação , Aminoácidos , Aminoácidos Sulfúricos , Dissulfetos , Concentração de Íons de Hidrogênio , Focalização Isoelétrica , Sementes/análise , Compostos de Sulfidrila
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