This study compared strategies to equalize the volume of aerobic exercise performed with different intensities by Wistar rats, based on the distance covered during exercise bouts and energy expenditure (EE, isocaloric sessions) obtained from oxygen uptake (V̇O2) or respiratory exchange ratio (RER). Thirty-three male rats (270.5±12.8 g) underwent maximal exercise tests to determine V̇O2 reserve (V̇O2R), being randomly assigned to three groups: moderate-intensity continuous exercise at speed corresponding to 50% V̇O2R (MIC; n=11); high-intensity continuous exercise at 80% V̇O2R (HIC; n=11); and high-intensity intermittent exercise (HII; n=11) at 60% V̇O2R (3 min) and 80% V̇O2R (4 min). Exercise duration was calculated individually to elicit EE of 5 kcal in each session. No difference between groups was found for total running distance (MIC: 801±46, HIC: 734±42, HII: 885±64 m; P=0.13). Total EE measured by RER was systematically underestimated compared to values obtained from V̇O2 (HII: 4.5% and MIC: 6.2%, P<0.05). Total EE (calculated from V̇O2), and duration of HIC bouts (2.8 kcal and 30.8±2.2 min) were lower (P<0.0001) than in MIC (4.9 kcal and 64.7±1.8 min) and HII (4.7 kcal and 46.9±2.2 min). Predicted and actual values of total V̇O2, total EE, and duration of isocaloric sessions were similar in MIC and HII (P>0.05), which were both higher than in HIC (P<0.0001). In conclusion, the time to achieve a given EE in exercise bouts with different intensities did not correspond to the total distance. Therefore, the volume of aerobic exercise in protocols involving Wistar rats should be equalized using EE rather than total covered distance.

The main purpose of this study was to investigate the level of agreement between the gas exchange threshold (GET) and heart rate variability threshold (HRVT) during maximal cardiopulmonary exercise testing (CPET) using three different exercise modalities. A further aim was to establish whether there was a 1:1 relationship between the percentage heart rate reserve (%HRR) and percentage oxygen uptake reserve ( % V ˙ O 2 R) at intensities corresponding to GET and HRVT. Sixteen apparently healthy men 17 to 28 years of age performed three maximal CPETs (cycling, walking, and running). Mean heart rate and V ˙ O 2 at GET and HRVT were 16 bpm (P<0.001) and 5.2 mL·kg-1·min-1 (P=0.001) higher in running than cycling, but no significant differences were observed between running and walking, or cycling and walking (P>0.05). There was a strong relationship between GET and HRVT, with R2 ranging from 0.69 to 0.90. A 1:1 relationship between %HRR and % V ˙ O 2 R was not observed at GET and HRVT. The %HRR was higher during cycling (GET mean difference=7%; HRVT mean difference=11%; both P<0.001), walking (GET mean difference=13%; HRVT mean difference=13%; both P<0.001), or running (GET mean difference=11%; HRVT mean difference=10%; both P<0.001). Therefore, using HRVT to prescribe aerobic exercise intensity appears to be valid. However, to assume a 1:1 relationship between %HRR and % V ˙ O 2 R at HRVT would probably result in overestimation of the energy expenditure during the bout of exercise.

INTRODUÇÃO E OBJETIVOS: Ciclosporina A é uma droga imunossupressora potente e efetiva no combate à rejeição de órgãos transplantados. No presente estudo, os autores avaliaram o emprego de um imunoensaio monoclonal com fluorescência polarizada (FPIAm), como um método alternativo ao radioimunoensaio (RIA) para determinação dos níveis de ciclosporina em sangue total. MATERIAL E MÉTODOS: Amostras de sangue de 65 pacientes submetidos a transplante renal foram colhidas em frascos com EDTA 12 horas após a última dose de ciclosporina, via oral. Os níveis de ciclosporina foram avaliados por meio de radioimunoensaio com anticorpo monoclonal e imunoensaio monoclonal com fluorescência polarizada. RESULTADOS E CONCLUSÃO: A análise estatística revelou um coeficiente de correlação entre os métodos de r = 0,9817 e o teste t de Student pareado mostrou haver diferença estatisticamente significaante entre eles (p<0,05). A análise da regressão revelou que os métodos poderiam ser comparáveis por meio da equação Cya(FPIAm) = 1,06xCya(RIA) + 5,8, mostrando que FPIAm é um excelente método alternativo ao RIA, com as vantagens de ser rápido, de fácil execução, reprodutível e com resultados comparavéis aos obtidos por RIA.

BACKGROUND: Cyclosporin A is a potent immunosuppressive drug effective in combatting rejection following organ transplantation. In na effort to replace a radioimmunoassay (RIA) for whole blood determination of cyclosporine (Cya) we compared RIA with fluorescence polarization immunoassay (FPIAm). METHOD: 65 blood samples were analysed from kidney transplanted patients. The samples were collected into tubes containing EDTA as anticoagulant and analysed by RIA and FPIAm. RESULTS: The statistical analysis revealed a difference between both methods (p<0.05). The linear-regression comparassion of Cya concentration measured by RIA and FPIAm showed the following relationship: Cya(FPIAm) = 1.06 x Cya(RIA) + 5.8 (r=0.9817). CONCLUSION: We conclude that FPIAm provides na alternative method for measuring cyclosporine in whole blood with the added advantages of being reasonably rapid, precise and easy to perform.