ABSTRACT
The focus of this study is to validate whether the sensitivity of dose distribution following the interface of different media can be used to distinguish between small variations of photon energy spectra in the context of the convolution/superposition algorithm in the polyenergetic implementation (Philips Pinnacle3, ADAC Laboratories, Milpitas, CA). Calculations were performed in homogeneous water and heterogeneous lung/water phantoms. Spectra were generated, in which the weights of the low-, medium- and high-energy components were adjusted sequentially. The heterogeneity correction factor CFlung, the D20/D10 ratio for homogeneous water and logarithmic derivative in buildup region LDbuildup were assessed for their relative ability to discriminate between different spectra for various field sizes. In accordance with another study (Charland et al 2004), the superior discrimination ability of the CFlung and LDbuildup tests over the D20/D10 test was observed for changes in an energy component as small as 0.3% of the total weight in the energy spectrum. Furthermore, new tests utilizing transverse dose profile data for discriminating between spectra, Fringe Index (FI) and Penumbra Index (PI), were introduced. The discrimination ability of the PI and FI tests was superior when a medium containing interface effects was exploited to obtain the transverse profile data (water/lung phantom for PIhung and FIlung tests) as opposed to when a homogeneous water medium was used (PIwater and FIwater tests).
Subject(s)
Algorithms , Equipment Failure Analysis/methods , Radiometry/methods , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Conformal/instrumentation , Radiotherapy, Conformal/methods , Software , Monte Carlo Method , Radiometry/instrumentation , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted/instrumentation , Reproducibility of Results , Scattering, Radiation , Sensitivity and SpecificityABSTRACT
Mature CD4(+) and CD8(+) T lymphocytes are believed to build and express essentially identical surface alphabeta T-cell receptor-CD3 (TCR.CD3) complexes. However, TCR.CD3 expression has been shown to be more impaired in CD8(+) cells than in CD4(+) cells when CD3gamma is absent in humans or mice. We have addressed this paradox by performing a detailed phenotypical and biochemical analysis of the TCR.CD3 complex in human CD3gamma-deficient CD8(+) and CD4(+) T cells. The results indicated that the membrane TCR.CD3 complex of CD8(+) T lymphocytes was conformationally different from that of CD4(+) lymphocytes in the absence of CD3gamma. In addition, CD8(+), but not CD4(+), CD3gamma-deficient T lymphocytes were shown to contain abnormally glycosylated TCRbeta proteins, together with a smaller, abnormal TCR chain (probably incompletely processed TCRalpha). These results suggest the existence of hitherto unrecognized biochemical differences between mature CD4(+) and CD8(+) T lymphocytes in the intracellular control of alphabetaTCR. CD3 assembly, maturation, or transport that are revealed when CD3gamma is absent. Such lineage-specific differences may be important in receptor-coreceptor interactions during antigen recognition.
Subject(s)
CD3 Complex/metabolism , CD4-Positive T-Lymphocytes/chemistry , CD8-Positive T-Lymphocytes/chemistry , Receptor-CD3 Complex, Antigen, T-Cell/chemistry , Blotting, Northern , CD4-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/metabolism , Calcium/metabolism , Flow Cytometry , Genes, T-Cell Receptor alpha/genetics , Herpesvirus 2, Saimiriine/immunology , Humans , Phenotype , Precipitin Tests , Protein Conformation , Receptor-CD3 Complex, Antigen, T-Cell/genetics , Receptors, Cell Surface/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Time Factors , Transcription, GeneticABSTRACT
Se presentan los resultados del examen físico, antropométrico y evaluación funcional de 29 deportistas integrantes de un equipo de cuarta división de fútbol, de sexo masculino, cuyas edades estuvieron comprendidas entre 18 y 21 años. Se relevaron sus hábitos alimentarios, se obtuvo su somatotipo y somatocarta y se midieron en forma indirecta su capacidad aeróbica, consumo máximo de oxígeno y pulso de oxígeno a partir de una prueba máxima en banda ergométrica. Se observó comportamiento normal de la frecuencia cardíaca y presión arterial durante la prueba de esfuerzo. La capacidad aeróbica promedio estuvo en los 17,5 Mets. El consumo máximo de O2 calculado y el pulso de oxígeno estuvieron dentro de valores esperados para un programa de entrenamiento correcto. La encuesta alimentaria reveló alto consumo de carnes rojas y bajo de verduras y frutas. El porcentaje graso está en niveles ideales mientras que el muscular es ligeramente bajo. El somatotipo promedio es mesomórfico.(AU)
Subject(s)
Humans , Male , Adolescent , Adult , Football , Oxygen Consumption , Body Composition , Diet , Feeding Behavior , Dietary Fats , Blood Pressure/physiology , Heart Rate/physiology , Physical Education and TrainingABSTRACT
Se presentan los resultados del examen físico, antropométrico y evaluación funcional de 29 deportistas integrantes de un equipo de cuarta división de fútbol, de sexo masculino, cuyas edades estuvieron comprendidas entre 18 y 21 años. Se relevaron sus hábitos alimentarios, se obtuvo su somatotipo y somatocarta y se midieron en forma indirecta su capacidad aeróbica, consumo máximo de oxígeno y pulso de oxígeno a partir de una prueba máxima en banda ergométrica. Se observó comportamiento normal de la frecuencia cardíaca y presión arterial durante la prueba de esfuerzo. La capacidad aeróbica promedio estuvo en los 17,5 Mets. El consumo máximo de O2 calculado y el pulso de oxígeno estuvieron dentro de valores esperados para un programa de entrenamiento correcto. La encuesta alimentaria reveló alto consumo de carnes rojas y bajo de verduras y frutas. El porcentaje graso está en niveles ideales mientras que el muscular es ligeramente bajo. El somatotipo promedio es mesomórfico.