Factors associated with care-seeking for low back pain when genetics and the familial environment are considered.

BACKGROUND: Low back pain (LBP) is the leading cause of disability worldwide. Care-seekers for LBP cause substantial economic burden to governments and the healthcare system. OBJECTIVE: To investigate lifestyle and health-related factors associated with care-seeking (including pain medication use) in individuals experiencing LBP, after controlling for important genetic and early environmental confounders through the use of a within-twin pair case-control design. DESIGN: A secondary analysis of observational longitudinal data, derived from the Australian Twin low BACK pain (AUTBACK) study, was performed on 66 twin pairs that presented with similar symptoms of LBP at baseline but became discordant for care-seeking behaviour over one month. METHODS: Subjective and objective assessment of pain intensity, disability, depression, sleep quality, physical activity and body mass index were performed. Data was analysed using stepwise conditional logistic regression in two stages: within-pair case-control for monozygotic and dizygotic twins together; and within-pair case-control analysis of monozygotic twins only. Results were expressed as odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Higher LBP intensity (OR 2.9; 95% CI 1.3-6.8) and poorer sleep quality (OR 10.9; 95% CI 1.5-77.7) were the main factors that increased the likelihood of care-seeking for LBP. These associations remained significant and increased in magnitude after adjusting for genetic confounding. CONCLUSIONS: Individuals with higher LBP intensity and worse sleep quality are more likely to seek care for LBP, and this relationship is likely to be causal after adjustment of familial and genetic confounding.

Quantification of Cry1Ac and Cry1F Bacillus thuringiensis insecticidal proteins in selected transgenic cotton plant tissue types.

Quantitative enzyme-linked immunosorbent assays were used to characterize the geographical (locations) and temporal (through 6 wk) expression of CrylAc, from Bacillus thuringiensis variety kurstaki, and Cry1F, from B. thuringiensis variety aizawai, in transgenic cotton, Gossypium hirsutum L., plant structures. Terminal leaves, squares (flower buds), flowers, bolls (fruit), and mature leaves located five and eight nodes below the terminal apex were sampled during weeks 2, 4, and 6 after the initiation of anthesis. The effect of location (environment) significantly influenced protein expression levels, although similar trends were observed across locations. Cry1F was expressed at levels greater (1.1-29.0-fold) than that for CrylAc in all structures with exception to flowers. In contrast, the level of CrylAc in flowers was generally greater than Cry1F. Within each sampling period, concentrations of Cry1F in mature leaves (five and eight node) were greater than that for other structures. Expression was also greater for older, eight-node mature leaves than younger, five-node mature leaves. CrylAc expression in bolls was lowest compared with terminal leaves, squares, flowers, and mature leaves, which expressed at similar concentrations. Cry1F expression increased through time for mature leaves and terminal leaves; whereas, a decline in Cry1Ac protein concentration was observed for terminal leaves and bolls. The data presented here provides a means to understand observed levels of efficacy (patterns of insect damage) by comparing the spatial and temporal dynamics of expression for Cry1Ac and Cry1F in PhytoGen 440W transgenic cotton.

Effect of supra-ambient oxygen on nitrogenase activity (c(2)h(2)) and root respiration of soybeans and isolated soybean bacteroids.

Isolated soybean (Glycine max [L.] Merr. cv Wilkin) bacteroids have O(2)-dependent nitrogenase activity which is strongly inhibited by supraoptimal O(2) concentrations. Oxygen-inhibited nitrogenase activity is recovered by addition of 10 millimolar sodium succinate or by lowering the O(2) concentration.Brief treatment of roots of intact soybean plants with 1.0 atmosphere O(2) reduces nitrogenase activity (C(2)H(2)). There is a rapid partial recovery of activity within 2 to 3 hours, and a slower return to near normal levels by 36 hours. The drop and recovery of nitrogenase activity is accompanied by a parallel drop and increase in root respiration. There is a direct relationship between the change in respiration and the change in acetylene reduction following O(2) treatment. The O(2)-mediated changes in nitrogenase activity and root respiration are not affected by the planting medium. The ratio of the change in respiration to the change in nitrogenase activity was the same in 13 soybean cultivars.

Root respiration associated with nitrogenase activity (c(2)h(2)) of soybean, and a comparison of estimates.

Root respiration associated with symbiotic fixation in soybean (Glycine max [L.] Merr.) was estimated by four methods.Averaged over the life of the plant, the root respires 5.8 milligrams C per milligram N accumulated from fixation. When nitrogenase (C(2)H(2)) activity and root respiration were decreased by treating roots briefly with 1.0 atmosphere O(2), the respiration associated with nitrogenase was estimated as 2.10 micromoles CO(2) per micromole C(2)H(4).When nitrogenase activity and respiration were decreased by addition of nitrate, the respiration associated with fixation was calculated as 2.90 micromoles CO(2) per micromole C(2)H(4). Removing nodules from roots decreased fixation and root respiration, and the ratio was 4.08 micromoles CO(2) per micromole C(2)H(4). When soybean plants were kept in prolonged darkness, then returned to light, the associated drop and recovery of respiration and nitrogenase activity had a ratio of 4.36 micromoles CO(2) per micromole C(2)H(2).