The accuracy of the ACSM cycle ergometry equation.

The purpose of this study was to determine the accuracy of the American College of Sports Medicine's equation for estimating the oxygen cost of exercise performed on a cycle ergometer. Sixty healthy males, ages 19-39 yr old, performed a five stage (30, 60, 90, 120, and 150 W) submaximal cycle ergometer test while their oxygen uptake was measured. Results indicated the standard error of estimate for the predicted oxygen values ranged from 0.11 to 0.22 l.min-1, with correlations between the actual and predicted values ranging from r = 0.22 to r = 0.50. Total errors ranged from 0.23 to 0.31 l.min-1. The actual oxygen cost was underestimated from 0.16 to 0.29 l.min-1 (P less than 0.05) by the equation at each workload. A revised equation was developed based upon the actual VO2-power relationship. The resulting slope was lower and the intercept higher when compared with the current ACSM equation. The slope and intercept of the revised equation are more consistent with values published in the literature. This equation appears as: VO2 (ml.min-1) = kgm.min-1 x 1.9 ml.min-1) + ((3.5 ml.kg-1.min-1 x kg body weight) + 260 ml.min-1). Predicted values from the revised equation were more accurate as reflected by slightly higher correlations, lower total errors, and lower mean differences from actual VO2 measurements than those from the current equation.

Impaired cell-mediated immune response in patients with congenital rubella: correlation with gestational age at time of infection.

Lymphocyte transformation, interferon, and leukocyte migration inhibition factor synthesis were studied in purified lymphocyte cultures for 20 children with congenital rubella and 18 healthy children (seven susceptible and 11 immune to rubella). Lymphocyte transformation after phytophemagglutinin stimulation was significantly lower in children with congenital rubella as compared to healthy controls. Responses to purified rubella virus were absent in the susceptible controls and absent or at least two times lower in congenital rubella children than in immune controls. After purified rubella virus stimulation, leukocyte migration inhibition factor production was detected in all immune controls, but in none of the susceptible controls, or the congenital rubella-infected children. The results varied with gestational age of intrauterine infection: the impairment of cellular immune response, both after phytohemagglutinin or rubella virus stimulation, was more severe in the children infected in the first two months than in the latter stages of gestation.

Progressive rubella panencephalitis: immunovirological studies and results of isoprinosine therapy.

Two patients with progressive rubella panencephalitis, one with and one without stigmata of congenital rubella, were treated for 9 months with isoprinosine and showed continued clinical deterioration. Immunoviorological studies performed before, during and after treatment were unaffected by drug therapy. The virus was recovered on one occasion from the lymphocytes of one of these cases. Neither patient showed any major defects in cellular or humoral immunity. However, the lymphocytes of the patient with stigmata of congenital rubella failed to respond to rubella virus in vitro and had a heat stable, non-dialysable serum inhibitor of in vitro protein A stimulated proliferative responses. Both patients' serum interfered with the production of interferon by normal donor lymphocytes following stimulation with rubella and varicella virus antigen. Increasing serum titres of interferon which did not appear to be lymphoid or immune-specific in origin were found in these two cases.