Relationships between oxygen uptake, dynamic body acceleration and heart rate in humans.

AIM: Accurate estimation of energy expenditure (EE) is important in human and animal behavior analysis. Rate of oxygen consumption (VO2) reflects EE during aerobic metabolism but is not always convenient. Alternative methods include heart rate (HR) and overall dynamic body acceleration (ODBA). A favorable ODBA-VO2 relationship was recently reported but the strength of association between VO2, ODBA, HR and its variability (HRV) is less clear. METHOD: Fifteen young (23±4 years) healthy males of similar aerobic fitness (maximal oxygen uptake, VO2max=49.7±8.5 mL·kg(-1)·min(-1)) carried out progressive maximal exercise. ODBA, HRV and V̇O2 were recorded continuously. Relationships between ODBA, HRV and V̇O2 were explored using regression methods. RESULTS: VO2 was strongly related to ODBA and RR during walking (R=0.45,0.30; P<5x10(-5)) and running (R=0.60,0.38; P<5x10(-5)). HRV was related to VO2 during walking only (R=0.11-0.26; 0.005

HIV-1 p24 antigen testing in blood banks: results from Saudi Arabia.

HIV-1 p24 antigen testing was introduced to increase sensitivity in the early detection of HIV infection in blood donors. Since the introduction of HIV-1 p24 antigen testing in Saudi Arabia, we have failed to detect a single positive case. Over a three-year period, only four indeterminates were detected out of 24,654 blood donors. All four proved negative by confirmatory testing. Based on this experience, we believe that resources would be better directed to pooled nucleic acid testing and that p24 serological testing should be abandoned.

The cost-saving potential of prevaccination antibody tests when implementing a mass immunization program.

A seroprevalence study of hepatitis A virus (HAV), hepatitis B virus (HBV), and varicella-zoster virus (VZV) was carried out among Saudi Arabian National Guard soldiers with the objective of determining the cost-saving potential of prevaccination antibody tests when implementing an immunization program for the soldiers. A systematic sampling of 450 blood samples from 1,350 soldiers who donated blood at our hospital was carried out. Antibody tests were performed using the enzyme-linked immunosorbent assay method. The seropositivity rates for antibodies to HAV, HBV, and VZV were 97.5, 17.8, and 88.5%, respectively. Comparing the cost of prevaccine screening with that of universal vaccination, it was estimated that savings of 76 and 32% could be effected for HAV and VZV. Conversely, screening for HBV before immunization could increase the cost of vaccinating against the disease by 49%. A seroprevalence study could be a useful cost-saving approach to a mass immunization program against endemic, natural immunity-conferring diseases.