The influence of supporting the Oxylog instrument on estimated maximal aerobic capacity during a step test and heart rate in a lifting test.

This study investigated the influence of wearing, an Oxylog mask and heart rate monitor while the Oxylog instrument was supported in a stand versus that of wearing the Oxylog mask, heart rate monitor, and the Oxylog instrument, on oxygen consumption (VO2) and heart rate response during a graduated submaximal step test protocol. Also, the predicted maximal aerobic capacities ( VO2max) produced by the two graduated step tests were compared. In addition, differences in the working heart rates in a submaximal lifting test were analyzed in two lifting tests, one with the participant wearing the Oxylog mask, heart rate monitor, and Oxylog instrument and the other required the participant to only wear a heart monitor. Seventeen experienced male manual materials handlers participated in the study, and each treatment was seen by each participant in a randomized Latin Square design. Results from the two investigations indicate that there was no significant difference in the estimated maximal oxygen consumption (p = 0.1384) and no significant difference in the heart rate between the two lift tests. The analysis did show that the 4th stage (participants reaching their physiological limits) of the step tests indicated a statistically significant difference (p = 0.0259 for oxygen consumption, and p = 0.0465 for heart rate).

Effectiveness of Waddell's nonorganic signs in predicting a delayed return to regular work in patients experiencing acute occupational low back pain.

STUDY DESIGN: Consecutive case series. OBJECTIVE: To determine whether the presence of Waddell's nonorganic signs in occupational, acute low back pain patients predicts a longer time before return to unrestricted regular work. SUMMARY OF BACKGROUND DATA: Waddell's nonorganic signs identify patients with chronic low back pain with a poor prognosis; however, they have not been used as an outcome predictor in patients with occupational, acute low back pain. METHODS: Standardized histories and physical examinations, including Waddell's signs were recorded at the first clinic visit (n = 143) by a single physician who was not blinded to the study's goals or methods. Those with chronic low back pain or complicating medical conditions (n = 88) were excluded. Data from patients exhibiting the nonorganic signs were compared with those from patients without the signs for time to return to regular work without restrictions and medical resource use. RESULTS: Fifty-five patients with acute work-related low back pain were included. One or more of the nonorganic signs were seen in 14 patients (25.5%) at the first appointment. The most common signs were simulated axial loading (78.6%) and simulated rotation (71.4%). Those with any nonorganic sign required a median 58.5 days to return to regular work compared with 15.0 days for those without (P < 0.0001). Patients exhibiting any nonorganic sign compared with those without used more physical therapy (50.0% vs. 12.2%; P < 0.01) and lumbar computed axial tomography (21.4% vs. 0.0%; P = 0.01). CONCLUSIONS: Patients with acute, occupational low back pain exhibiting Waddell's nonorganic signs had a four times lengthier time for return to unrestricted, regular work and a greater use of physical therapy and lumbar computed tomographic scans.

Respiratory allergenicity of detergent enzymes in the guinea pig intratracheal test: association with sensitization of occupationally exposed individuals.

A guinea pig intratracheal test was used to set occupational operating guidelines for new enzyme proteins used in the detergent industry. In these studies, animals were intratracheally dosed with different levels of enzyme protein and sera from the animals were titered for allergic antibody to the enzyme. The amount of antibody produced to an enzyme was compared to the amount of antibody produced to the same protein doses of Alcalase, for which effective operating guidelines exist. These comparisons were used to determine if a new enzyme was more potent, less potent, or equivalent to Alcalase; operating guidelines were then established for the new enzyme. Termamyl was about 10-fold more potent than Alcalase and the protease subtilisin B was shown to be less potent. Another protease, Savinase, was shown to be equivalent in potency to Alcalase. The operating guidelines for Termamyl were adjusted lower, whereas the operating guidelines for the proteases were set the same as that of Alcalase. Under these conditions, we would predict that sensitizations to new enzymes would be comparable to or lower than the sensitizations to Alcalase. Prospective evaluation of skin prick test data of factory workers showed that sensitizations to Termamyl and Savinase were similar to sensitizations to Alcalase. The sensitizations to subtilisin B were lower than those to Alcalase. During this time period (7 years), only three respiratory incidents (rhinitis) were reported, demonstrating that employees with positive skin prick tests can continue to work. These comparisons indicate that the guinea pig intratracheal test is a good animal model for evaluating enzymes as respiratory allergens and that the data generated can be used to set operating guidelines for occupational allergens.

Characterization of skin prick testing responses for detecting sensitization to detergent enzymes at extreme dilutions: inability of the RAST to detect lightly sensitized individuals.

We observed that a group of detergent enzyme workers with known exposure to the subtilisin enzyme, Alcalase (Novo Industries, Bagsvaerde, Denmark), exhibited percutaneous sensitivity to Savinase (Novo Industries), a microbial protease, to which there was no previous occupational exposure. This was attributed to either cross-reactivity between these enzymes or to foreign enzyme contaminants contained in the Savinase antigen. The aims of this study were to determine the range of concentrations eliciting percutaneous responses to Alcalase and to another enzyme, Rapidase (an alpha-amylase) (Gist Brocades, Belgie, Netherlands); to compare the sensitivity of RAST and skin prick testing; and to characterize the relationship between wheal size and antigen concentration. Prick testing was conducted over six log10 antigen dilutions of Alcalase and Rapidase in 30 workers with previous exposure and skin reactivity to enzymes (group 1) and compared to nonexposed control groups, which included 60 atopic subjects (group 2) and 30 nonatopic subjects (group 3). The RAST was performed with Alcalase and Rapidase antigens. The percutaneous threshold concentrations in group 1 subjects varied widely from 10(3) to 10(-3) micrograms of protein per milliliter. Of 19 group 1 workers with skin test reactivity to Alcalase, 84% had positive RAST results; 83% of 24 workers who were reactive to Rapidase had positive RAST results. It was concluded that skin prick testing is preferred over in vitro methods for longitudinal monitoring of human sensitization to workplace allergens. In addition, the data predicted that based on a known Alcalase level of 0.07% in Savinase, 26% of Alcalase-sensitized subjects could react to Savinase. An excellent correlation (r > 0.97) was found between log concentration of antigen and wheal size parameters, with the log diameter and log area performing equally as well (r > 0.98). Analysis of variance revealed that more than 60% of intragroup variation represented human variability in wheal parameters at each concentration tested, whereas at least 95% of intergroup variation was due to regression. The excellent correlations of both wheal diameter and area with antigen concentrations were attributed to the very small changes observed between test concentrations.