RESUMO
For high-intensity cycle ergometer exercise, the tolerable duration (t) is well characterized as a hyperbolic function of power output, P : t = W'/(P-thetaF), where thetaF may be termed the "fatigue threshold." The purpose of this study was to determine the effect of oral creatine (Cr) supplementation on the curvature constant parameter (W') of the power-duration curve. A double-blind research method and a cross-over design were employed for creatine/placebo supplementation. Eight healthy male subjects (aged 18 to 22 years) each performed four or five high-intensity square-wave exercise bouts on an electrically braked cycle ergometer after 5 d of Cr monohydrate (CR: 20 g of Cr with artificial sweetener/d) or placebo (PL: 6 g of glucose/d) supplementation. Each subject performed a single high-intensity exercise trial per day for four or five successive days to determination the P-t hyperbolic relation. After 6 weeks (the washout time of Cr from the muscles), each subject performed the other condition (i.e., PL or CR) and repeated the same experimental procedure. There was no significant difference for thetaF between PL and CR conditions (PL: 214.4 +/- 23.6, CR: 207.0 +/- 19.8 W, mean +/- SD). In contrast, W' was significantly increased by the Cr supplementation (PL: 10.9 +/- 2.7, CR: 13.7 +/- 3.0 kJ; p<0.05). The results indicated that Cr and/or PCr content in muscles seems to be one of the important determinants of the curvature constant parameter (W') of the power-duration hyperbolic curve for cycle ergometry.
Assuntos
Creatina/administração & dosagem , Creatina/fisiologia , Exercício Físico/fisiologia , Administração Oral , Adulto , Ergometria , Humanos , MasculinoRESUMO
We experienced a case of tracheoesophageal fistula successfully cured by surgical therapy after blunt trauma received 38 years ago. A 71-year-old man was injured blunt trauma at right chest by traffic accident in 1960, and was treated for pneumothorax and ribs fracture. In April, 1998, the patient came to the hospital for hemoptysis. Tracheoesophageal fistula at membranous wall 3 cm upper from the carina was diagnosed and operation was performed. Severe adhesion at 3 cm upper from carina was thought to be fistula. Incision was made at lateral esophageal wall and the fistula was confirmed at the esophageal anterior wall and the esophagus was cut in a circle around the fistula. Trachea was closed 1 layer sutures using esophageal all layers and esophagus was closed with 2 layer sutures. A pedicled 4th intercostal muscle was interposed between the tracheal and esophageal suture lines. Prevention of tracheal stenosis was possible without resection of fistula and closure of trachea using esophageal all layers. This operation was seemed to be effective. This case is supposed to be the longest delay between time of injury and its repair in the world.
Assuntos
Traumatismos Torácicos/complicações , Fístula Traqueoesofágica/cirurgia , Ferimentos não Penetrantes/complicações , Acidentes de Trânsito , Idoso , Esôfago/cirurgia , Humanos , Masculino , Fatores de Tempo , Traqueia/cirurgia , Fístula Traqueoesofágica/etiologia , Resultado do TratamentoRESUMO
A chronic myeloproliferative disorder associated with monosomy 7 is described in a 3 1/2-year-old boy. His presenting features closely resembled those of juvenile chronic myeloid leukaemia (JCML). Cytogenetic study of bone marrow cells showed that all of the metaphases examined had chromosome 7 deletions. He developed an erythroblastic phase, characterized by anaemia, marked erythroid hyperplasia of bone marrow and the appearance of nucleated red blood cells in the peripheral blood. During the erythroblastic phase, blood transfusion resulted in a suppression of erythropoiesis as evidenced in both the peripheral blood and bone marrow. The in vitro culture studies showed that the erythroid precursor was dependent upon erythropoietin (Ep) for differentiation and proliferation during the erythroblastic phase. However, the Ep dose-response curve showed that a peak of erythroid colony formation occurred at a lower concentration than in the healthy controls. These findings suggest that although the erythroid precursor remains under the control of Ep, it has an increased sensitivity to Ep during the erythroblastic phase of monosomy 7.