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1.
Percept Mot Skills ; 126(6): 1178-1194, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31422740

RESUMO

Allowing learners to control feedback has been an effective strategy in motor skills learning. However, most studies of self-controlled (SC) feedback have used simple tasks that may be dissimilar to sports skills that generally demand more degrees of freedom and cognition. Thus, this study investigated the effects of SC knowledge of results (KR) on learning a complex Taekwondo skill. Twenty-four undergraduate volunteers of both sexes, aged 18-35 years, practiced a specific serial Taekwondo skill that was novel to them. We divided participants randomly into SC and yoked groups and compared their performance after they learned a specific displacement sequence, finishing with a lateral kick (bandal-tchagui) at a punching bag within a target time span. During acquisition, all participants performed 48 trials divided into six blocks and, on a retention test 24 hours later, they performed 10 more trials. We found that both groups reduced their errors from the first to the last block of the acquisition phase and that the SC group showed a better performance on the retention test, relative to the yoked control group. SC KR participants requested KR mainly after good trials, though they showed no statistically significant differences between trials with and without KR. Their inefficiency in estimating their own errors may have been due to task complexity, since many aspects of the task beyond its temporal requirement demanded the learners' attention. Our results, using a novel Taekwondo serial skill, confirm and extend the benefits of SC KR from just simple motor learning in past studies to learning complex motor skills.


Assuntos
Conhecimento Psicológico de Resultados , Artes Marciais , Destreza Motora , Autocontrole , Adolescente , Adulto , Atenção , Cognição , Retroalimentação , Retroalimentação Psicológica , Feminino , Glicoesfingolipídeos , Humanos , Aprendizagem , Masculino , Adulto Jovem
2.
Percept Mot Skills ; 125(2): 400-416, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29350078

RESUMO

Providing the learner control over aspects of practice has improved the process of motor skill acquisition, and self-controlled knowledge of results (KR) schedules have shown specific advantages over externally controlled ones. A possible explanation is that self-controlled KR schedules lead learners to more active task involvement, permitting deeper information processing. This study tested this explanatory hypothesis. Thirty undergraduate volunteers of both sexes, aged 18 to 35, all novices in the task, practiced transporting a tennis ball in a specified sequence within a time goal. We compared a high-involvement group (involvement yoked, IY), notified in advance about upcoming KR trials, to self-controlled KR (SC) and yoked KR (YK) groups. The experiment consisted of three phases: acquisition, retention, and transfer. We found both IY and SC groups to be superior to YK for transfer of learning. Postexperiment participant questionnaires confirmed a preference for receiving KR after learner-perceived good trials, even though performance on those trials did not differ from performance on trials without KR. Equivalent IY and SC performances provide support for the benefits of task involvement and deeper information processing when KR is self-controlled in motor skill acquisition.


Assuntos
Retroalimentação Psicológica/fisiologia , Conhecimento Psicológico de Resultados , Destreza Motora/fisiologia , Autocontrole/psicologia , Transferência de Experiência/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
3.
Med Phys ; 39(6Part9): 3698, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28519025

RESUMO

PURPOSE: The goal of this study is to evaluate the predictability of a novel method using a self background-corrected maximum Standard Uptake Value (cSUVmax) from 18F-FDG Positron Emission Tomography (PET) of the patients following lung cancer stereotactic body radiosurgery (SBRT). METHODS: 20 qualified patients treated out of 38 patients treated with SBRT for a single lung malignant lesion between May 2009 and December 2009 were enrolled in the cohort study. All had pre- and at least one post-treatment PET images available at the time of study. The mean normal tissue SUV from the descending aorta was sampled as baseline to divide SUVmax of tumor site. The resultant cSUVmax was used for assess the local control or possible recurrence. The Result was then compared with that using SUVmax alone method. RESULTS: The average follow-up length was 48.9 weeks ranging from 18.6 to 115.0 weeks. The mean SUV of aorta was measured as 1.821±0.364, ranging from 1.173 to 2.576. From the pre-treatment PET, 70% and 65% was indicated positive correspondingly when using SUVmax with 2.50 and cSUVmax with 1.52 thresholds. When PET was taken < 29 weeks post-SBRT, 75% and 67% respectively showed higher values in the locally controlled group. For PET = 29 weeks after SBRT, with cSUVmax both locally controlled and recurrent groups are accurately identified, while SUVmax shows 5% false positive and one possible false negative. CONCLUSIONS: The SUVmax in lung tumor site corrected by the mean SUV of descending aorta or cSUVmax provided a more reliable parameter than using SUVmax alone in predicting the local control and recurrence for follow-up PET of patients after lung SBRT. The method used in this study objectively displayed a strong correlation between low cSUVmax and local control following lung SBRT in this investigation, otherwise a local recurrence is suggested.

4.
Eur Biophys J ; 31(6): 478-84, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12355257

RESUMO

Oxy- as well as deoxymyoglobin exhibit a pronounced temperature dependence of the quadrupole splitting of the heme iron as detected by conventional Mössbauer spectroscopy. With nuclear resonant forward scattering (NFS) of synchrotron radiation, which can be viewed as Mössbauer spectroscopy in the time domain, it is shown that this spectroscopic behavior, although it is phenomenologically similar in the two cases, is based on completely different physical mechanisms. It is demonstrated that stochastic fluctuations of the iron electric field gradient in MbO(2), which are due to the dynamic structural disorder of the FeO(2) moiety, are the reason for the temperature-dependent alterations of the coherent quantum beat pattern in the NFS spectra of MbO(2), in contrast to deoxyMb where transitions between orbital states of iron take place. This subtle spectroscopic difference cannot be inferred from conventional Mössbauer spectroscopy.


Assuntos
Hemoglobinas/química , Ferro/química , Mioglobina/química , Oxigênio/química , Espectroscopia de Mossbauer/métodos , Eletroquímica/métodos , Conformação Molecular , Espalhamento de Radiação , Análise Espectral/métodos , Processos Estocásticos , Temperatura
5.
J Biol Chem ; 276(46): 42881-6, 2001 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-11553635

RESUMO

Adenosine 5'-phosphosulfate reductase (APR) catalyzes the two-electron reduction of adenosine 5'-phosphosulfate to sulfite and AMP, which represents the key step of sulfate assimilation in higher plants. Recombinant APRs from both Lemna minor and Arabidopsis thaliana were overexpressed in Escherichia coli and isolated as yellow-brown proteins. UV-visible spectra of these recombinant proteins indicated the presence of iron-sulfur centers, whereas flavin was absent. This result was confirmed by quantitative analysis of iron and acid-labile sulfide, suggesting a [4Fe-4S] cluster as the cofactor. EPR spectroscopy of freshly purified enzyme showed, however, only a minor signal at g = 2.01. Therefore, Mössbauer spectra of (57)Fe-enriched APR were obtained at 4.2 K in magnetic fields of up to 7 tesla, which were assigned to a diamagnetic [4Fe-4S](2+) cluster. This cluster was unusual because only three of the iron sites exhibited the same Mössbauer parameters. The fourth iron site gave, because of the bistability of the fit, a significantly smaller isomer shift or larger quadrupole splitting than the other three sites. Thus, plant assimilatory APR represents a novel type of adenosine 5'-phosphosulfate reductase with a [4Fe-4S] center as the sole cofactor, which is clearly different from the dissimilatory adenosine 5'-phosphosulfate reductases found in sulfate reducing bacteria.


Assuntos
Proteínas Ferro-Enxofre/química , Magnoliopsida/enzimologia , Oxirredutases atuantes sobre Doadores de Grupo Enxofre , Oxirredutases/química , Oxirredutases/fisiologia , Plantas/enzimologia , Sequência de Aminoácidos , Arabidopsis/enzimologia , Espectroscopia de Ressonância de Spin Eletrônica , Escherichia coli/metabolismo , Ferro/metabolismo , Proteínas Ferro-Enxofre/fisiologia , Cinética , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Proteínas de Plantas/metabolismo , Ligação Proteica , Proteínas Recombinantes/metabolismo , Espectrofotometria , Espectroscopia de Mossbauer , Enxofre/metabolismo , Fatores de Tempo , Raios Ultravioleta
6.
Phys Rev Lett ; 86(7): 1351-4, 2001 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-11178081

RESUMO

Nuclear inelastic scattering (NIS) spectra were recorded for a monocrystal of the spin-crossover complex [Fe(tptMetame)] (ClO (4))(2) (tptMetame = 1,1,1-tris([N-(2-pyridylmethyl)-N-methylamino]-methyl)ethane) at T = 30 K (low-spin state) and at room temperature (high-spin state) for different crystal orientations. The high energy resolution (0.65 meV) allowed us to resolve individual molecular vibrations which were unambiguously identified by density functional calculations. From the NIS spectra for the first time the angular-resolved iron-partial density of phonon states (PDOS) was extracted. The PDOS corroborates a vibrational entropy difference as driving force of the spin transition.

7.
FEBS Lett ; 459(3): 411-4, 1999 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-10526175

RESUMO

The nature and properties of the iron-sulphur (Fe-S) cluster in as-prepared and reduced biotin synthase of Escherichia coli have been investigated by Mössbauer spectroscopy. Our data clearly demonstrate that in the as-prepared sample, the cluster is present as [2Fe-2S](2+) with isomer shift, delta = 0.29 mm/s and quadrupole splitting, DeltaE(Q) = 0.53 mm/s, indicating incomplete cysteinyl-S coordination. Anaerobic reduction by dithionite in the presence of 55% (v/v) glycerol converts this form to [4Fe-4S](2+) (delta = 0.45 mm/s and DeltaE(Q) = 1.11 mm/s) and is accompanied by some destruction to Fe(2+). This cluster conversion is reversible and when exposed to air, the [4Fe-4S](2+) cluster is quantitatively reconverted to the [2Fe-2S](2+) cluster without any further cluster degradation.


Assuntos
Escherichia coli/enzimologia , Ferro/química , Sulfurtransferases/metabolismo , Ar , Proteínas Ferro-Enxofre/metabolismo , Espectroscopia de Mossbauer , Sulfurtransferases/química
8.
J Biol Inorg Chem ; 4(6): 708-16, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10631602

RESUMO

A model heme complex, bis(3-aminopyrazole)tetraphenylporphinatoiron(III) chloride, [TPPFe (NH2PzH)2]Cl, for which the EPR g-values lead to a rhombicity V/delta = 1.2 if gzz is the largest g-value, have been investigated by electron spin echo envelope modulation (ESEEM) and Mössbauer spectroscopies. The ESEEM studies focus on the proton sum frequency peaks at near twice the proton Larmor frequency. Analysis of the distant proton peak (mainly due to the pyrrole-H) at exactly twice the proton Larmor frequency shows conclusively that gzz is aligned along the normal to the porphyrin plane, and thus the electron configuration is (dxy)2(dxz,dyz)3, with gzz > gyy > gxx. This system is thus another violation to Taylor's "proper axis system" rule. The near proton (the alpha-H and N-H of the axial ligands) peaks provide distance information for those protons from the metal. Magnetic Mössbauer studies of the same complex confirm the (dxy)2(dxz,dyz)3 ground state and indicate that, as is the case for cytochrome P450cam, Axx is the largest magnitude A-value, and is negative in sign. Other low-spin iron(III) porphyrinates also have Axx of negative sign, but usually the magnitude is only about half that of Azz, which is always positive in sign.


Assuntos
Compostos Férricos/química , Metaloporfirinas/química , Modelos Químicos , Espectroscopia de Ressonância de Spin Eletrônica , Estrutura Molecular , Espectroscopia de Mossbauer
9.
Crit Rev Oncog ; 7(5-6): 457-64, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-9467667

RESUMO

Invasive bladder cancer remains a therapeutic challenge. Approximately 50% of patients treated with radical cystectomy die of metastatic disease. External beam radiation therapy when given alone has results inferior to that of surgery, and although it has shown some benefit when given in the preoperative setting, this was not verified by randomized trials. Altered fractionation radiation schemes and combined modality using a cisplatin-based combination chemotherapy with radiation have resulted in up to 60% bladder preservation.


Assuntos
Braquiterapia , Radioterapia/métodos , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/radioterapia , Ensaios Clínicos como Assunto , Terapia Combinada , Humanos , Invasividade Neoplásica , Neoplasias da Bexiga Urinária/cirurgia
10.
Sb Lek ; 96(2): 75-83, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8718791

RESUMO

The authors analyzed acute exacerbations of chronic hepatitis B in 24 chronic HBsAg carriers (20 with positive HBeAg, 4 with anti-HBe), more than half of whom were treated with glucocorticoids, by examining specific antigens and antibodies of the hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis delta virus (HDV), Epstein-Barr virus (EBV) and cytomegalovirus (CMV). Of 38 observed exacerbations of the disease they found in 7 (18%) deterioration after discontinuation of glucocorticoids, in 7 (18%) seroconversion of HBeAg to anti-HBe, in 9 (24%) spontaneous exacerbation of chronic hepatitis B, in 11 (29%) chronic activation, reactivation of EBV superinfection, in 3 (8%) CMV reactivation or superinfection and in one (3%) HDV superinfection. In no instance HAV superinfection was observed. Exacerbations were found five times more frequently in subjects in the stage of active viral replication (in HBeAg+ subjects) than in subjects with anti-HBe. In eight patients EBV reactivation was found after glucocorticoids withdrawal: in five patients after an average period of 5 months (range 3-7) and in three patients after an average period of 33 months (range 22-48). The results provide evidence that in addition to already known causes of acute exacerbations of chronic hepatitis B in our geographical area probably an important cause of deterioration of hepatitis is reactivation or superinfection with EBV and CMV in some patients in conjunction with previous glucocorticoid treatment.


Assuntos
Hepatite C/fisiopatologia , Doença Aguda , Adolescente , Adulto , Idoso , Anticorpos Antivirais/análise , Doença Crônica , Citomegalovirus/imunologia , Feminino , Anticorpos Anti-Hepatite/análise , Antígenos de Superfície da Hepatite B/análise , Hepatite C/imunologia , Hepatite C/virologia , Herpesvirus Humano 4/imunologia , Humanos , Masculino , Pessoa de Meia-Idade
12.
Cancer Lett ; 78(1-3): 41-8, 1994 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-8180967

RESUMO

Sodium phenylacetate (NaPA) at concentrations ranging from 2 to 10 mM promoted myogenic differentiation of the human alveolar rhabdomyosarcoma cell line KFR. These concentrations inhibited DNA synthesis of the cells in a dose-dependent manner without significant effect on cell viability. The morphological differentiation of small mononuclear elements to terminal, elongated multinuclear structures resembling myotubes was accompanied by the expression of skeletal muscle myosin. The proportion of differentiated myosin-positive cells which was around 0.8-1.7% in control cultures 12 days after seeding was increased by NaPA treatment up to 47%. In the cytoplasm of differentiated cells, features of sarcomerogenesis were observed. These results suggest that NaPA is an effective inducer of rhabdomyosarcoma cell differentiation at concentrations that have been achieved in humans with no significant adverse effects.


Assuntos
Músculos/citologia , Fenilacetatos/farmacologia , Rabdomiossarcoma/patologia , Diferenciação Celular/efeitos dos fármacos , Humanos , Microscopia Eletrônica , Miosinas/metabolismo , Tretinoína/farmacologia , Células Tumorais Cultivadas
13.
Arch Virol ; 138(3-4): 391-401, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-7998845

RESUMO

The replication of human cytomegalovirus (HCMV) was investigated in a new human rhabdomyosarcoma cell line (KFR) with morphological and biochemical characteristics of fetal striated muscle precursors (rhabdomyoblasts). KFR cells exhibited the unique property for spontaneous morphological transformation from a poorly-differentiated state into well-differentiated (myotube-like) rhabdomyoblasts. The poorly-differentiated rhabdomyoblasts promoted both complete viral gene expression and the production of infectious virus. In contrast, in well-differentiated rhabdomyoblasts HCMV infection was abortive. The results showed that replication of HCMV in this human rhabdomyosarcoma cell line depended on the state of cellular differentiation.


Assuntos
Citomegalovirus/fisiologia , Músculo Esquelético/virologia , Replicação Viral , Antígenos Virais/biossíntese , Sequência de Bases , Diferenciação Celular , Citomegalovirus/imunologia , Humanos , Proteínas Imediatamente Precoces/biossíntese , Dados de Sequência Molecular , Músculo Esquelético/citologia , Rabdomiossarcoma/patologia , Células Tumorais Cultivadas , Proteínas Virais/biossíntese
14.
Acta Virol ; 33(5): 435-46, 1989 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2576584

RESUMO

Some parameters of specific and non-specific immunity were tested in a group of 44 subjects suffering from frequent herpes simplex type 1 (HSV-1) or herpes simplex type 2 (HSV-2) recrudescences. The tests performed included determinations of (i) HSV complement-independent and complement-dependent neutralizing antibodies, (ii) antibodies to glycoprotein C of HSV-1 and glycoprotein G of HSV-2, (iii) antibodies to viral capsid and early antigens of Epstein-Barr virus, (iv) antibodies to tetanus toxoid, (v) serum levels of IgM, IgG, IgA, transferrin, prealbumin and C'3 and C'4 components of complement, (vi) active and total T lymphocytes, (vii) phagocyting activity of polymorphonuclear neutrophils, eosinophils and mononuclear cells, (viii) skin reactivity to tuberculin, toxoplasmin, candidin, tetanus and diphtheria toxoids. In the patients the following deviations from the control groups were noted: (i) Antibody levels to homotypic but not to heterotypic HSV were enhanced, (ii) serum IgM levels were elevated, (iii) percentages and numbers of active and total T lymphocytes were decreased, (iv) phagocyting activity of neutrophils was depressed but that of eosinophils was increased.


Assuntos
Herpes Simples/imunologia , Adolescente , Adulto , Idoso , Anticorpos Antivirais/análise , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fagocitose , Recidiva , Simplexvirus/imunologia , Testes Cutâneos , Linfócitos T/imunologia
15.
Artigo em Inglês | MEDLINE | ID: mdl-2723420

RESUMO

Hybridomas secreting HBsAg antibodies were obtained by fusing murine myeloma cell line P3-X63-Ag8 to spleen cells of BALB/c mice sensitized with HBsAg. The surface antigen used for immunization of mice was prepared by purification from pooled human plasma specimens. Resulting monoclonal antibodies were detected by the SPRIA method. Clones producing highest anti-HBs titres were used to prepare mouse ascitic fluids. Monoclonal antibodies in ascitic fluid reached a titre of 10(6) to 10(7) at a protein concentration of 1 mg per ml. Two of the prepared monoclonal antibodies, HBS-01 and HBS-02, both belonging to IgG1 subclass of immunoglobulins, were selected for further study in order to assess their potential useability in the commercial ELISA kit. The pI values for HBS-01 ranged from 6.60 to 6.85, for HBS-02 from 5.6 to 6.1. In solid phase ELISA test the use of HBS-01 antibody improved accuracy of the assay by increasing its detection sensitivity for HBsAg subtypes adw and ayw in the reference serum; this sensitivity was evidently much better than that seen with the commercially available rabbit polyclonal anti-HBsAg antibody. The monoclonal antibody HBS-01 is specific to the determinant "a", which makes it suitable for use in ELISA test aimed at HBsAg detection. The antibody HBS-02 showed a markedly better reaction with HBsAg subtype adw than subtype ayw and can thus be used with advantage for their discrimination.


Assuntos
Anticorpos Monoclonais , Anticorpos Anti-Hepatite B/análise , Antígenos de Superfície da Hepatite B/imunologia , Animais , Anticorpos Monoclonais/análise , Anticorpos Monoclonais/biossíntese , Líquido Ascítico/análise , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Hibridomas , Camundongos , Camundongos Endogâmicos BALB C , Padrões de Referência
16.
Vaccine ; 6(3): 223-8, 1988 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2844031

RESUMO

The safety and efficacy of a subunit herpes simplex virus (HSV) type 1 vaccine were tested in a small-scale double-blind trial carried out in a group of 42 volunteers suffering from frequent recurrences of herpetic lesions. The patients were paired according to sex, age, type of virus isolated, previous history of the disease and some non-specific immunological markers. One member of each pair received repeated doses of HSV vaccine, the other a placebo. Clinical reactions were mild. Antibody responses following the vaccination were generally low and were almost entirely limited to subjects suffering from HSV-2 lesions. A majority of the patients exhibited improvement of their condition during the postvaccination period. These improvements were, however, nearly equally distributed between the vaccine and placebo groups.


Assuntos
Herpes Simples/prevenção & controle , Simplexvirus/imunologia , Vacinas Virais , Adolescente , Adulto , Idoso , Anticorpos Antivirais/biossíntese , Ensaios Clínicos como Assunto , Testes Imunológicos de Citotoxicidade , Método Duplo-Cego , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Placebos , Radioimunoensaio , Recidiva , Vacinas Virais/efeitos adversos
17.
Artigo em Inglês | MEDLINE | ID: mdl-2848884

RESUMO

Two-step differential centrifugation through 40% and 20% sucrose of 20% water extracts of HAV-positive stools yielded specific defined antigens for hepatitis A serological diagnosis by 3rd-generation methods. The antigens would be suitable also for other purposes. Products of comparable quality were obtained from HAV-positive stools yielding different amounts of virus. Optimal were incubation-period stools, where the loss in HAV yield was minimal; these preparations displayed the highest antigenic capacity and could be diluted up to 150 fold for serological reactions. Results obtained in extensive preliminary experiments, outlined in the Discussion, corroborated the advantages and efficiency of the proposed technology.


Assuntos
Fezes/microbiologia , Hepatovirus/isolamento & purificação , Técnicas Microbiológicas , Antígenos Virais/isolamento & purificação , Centrifugação com Gradiente de Concentração , Hepatite A/diagnóstico , Hepatovirus/imunologia , Hepatovirus/ultraestrutura , Humanos
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