Drivers of international variation in prevalence of disabling low back pain: Findings from the Cultural and Psychosocial Influences on Disability study.

BACKGROUND: Wide international variation in the prevalence of disabling low back pain (LBP) among working populations is not explained by known risk factors. It would be useful to know whether the drivers of this variation are specific to the spine or factors that predispose to musculoskeletal pain more generally. METHODS: Baseline information about musculoskeletal pain and risk factors was elicited from 11 710 participants aged 20-59 years, who were sampled from 45 occupational groups in 18 countries. Wider propensity to pain was characterized by the number of anatomical sites outside the low back that had been painful in the 12 months before baseline ('pain propensity index'). After a mean interval of 14 months, 9055 participants (77.3%) provided follow-up data on disabling LBP in the past month. Baseline risk factors for disabling LBP at follow-up were assessed by random intercept Poisson regression. RESULTS: After allowance for other known and suspected risk factors, pain propensity showed the strongest association with disabling LBP (prevalence rate ratios up to 2.6, 95% CI: 2.2-3.1; population attributable fraction 39.8%). Across the 45 occupational groups, the prevalence of disabling LBP varied sevenfold (much more than within-country differences between nurses and office workers), and correlated with mean pain propensity index (r = 0.58). CONCLUSIONS: Within our study, major international variation in the prevalence of disabling LBP appeared to be driven largely by factors predisposing to musculoskeletal pain at multiple anatomical sites rather than by risk factors specific to the spine. SIGNIFICANCE: Our findings indicate that differences in general propensity to musculoskeletal pain are a major driver of large international variation in the prevalence of disabling low back pain among people of working age.

Effect of attention bias modification on event-related potentials in patients with irritable bowel syndrome: A preliminary brain function and psycho-behavioral study.

BACKGROUND: Attention bias modification normalizes electroencephalographic abnormalities in alpha and beta power percentages related to attention in patients with irritable bowel syndrome (IBS). Yet, it is unknown whether ABM contributes to the normalization of event-related potentials (ERP) in these patients. We hypothesized that ERP related to attention deficit would be normalized after ABM implementation in individuals with IBS. METHODS: Thirteen patients with IBS and 10 control subjects completed a 2-month intervention that included five ABM sessions. Each session included 128 trials, resulting in a total of 640 trials during the study period. Event-related potentials were measured at the first and fifth sessions. As per the international 10-20 system for electroencephalographic electrode placement, right parietal P4 was evaluated to measure the attention component of facial expression processing. KEY RESULTS: A group comparison of P100 latency at P4 revealed that latencies were significantly different between groups in session 1 (IBS vs control, 108 ± 8 vs 97 ± 14; t = -2.51, P = .0203). This difference was absent in session 5 (94 ± 11 vs 93 ± 11, respectively; t = -0.397, P = .6954, r = .09), indicating an effect of ABM in the IBS group. CONCLUSIONS AND INFERENCES: Attention bias modification may have clinical utility for normalizing brain function and specifically attentional abnormalities in patients with IBS.

Formation of a three-dimensional network of V trimers in A2V13O22 (A=Ba, Sr).

We found that in A2V13O22 (A=Ba, Sr), which contains a trilayer slab of VO in the sodium-chloride structure with periodically missing ions, the trimerization of V ions occurs at 290 K (A=Ba) and 380 K (A=Sr). V trimers form a three-dimensional network, but some V ions remain untrimerized in these compounds. The suppression of magnetic susceptibility with trimerization and the existence of a Curie tail at low temperatures, together with the result of NMR measurement, indicate that the V trimers are spin singlet, whereas the untrimerized V ions have a magnetic moment; i.e., there is a spontaneous separation between nonmagnetic and magnetic ions in the crystal.

Reversing the direction of paced ventricular and atrial wavefronts reveals an oblique course in accessory AV pathways and improves localization for catheter ablation.

BACKGROUND: The purpose of this study was to determine how often accessory atrioventricular (AV) pathways (AP) cross the AV groove obliquely. With an oblique course, the local ventriculoatrial (VA) interval at the site of earliest atrial activation (local-VA) and the local-AV interval at the site of earliest ventricular activation (local-AV) should vary by reversing the direction of the paced ventricular and atrial wavefronts, respectively. METHODS AND RESULTS: One hundred fourteen patients with a single AP were studied. Two ventricular and two atrial pacing sites on opposite sides of the AP were selected to reverse the direction of the ventricular and atrial wavefronts along the annulus. Reversing the ventricular wavefront increased local-VA by >/=15 ms in 91 of 106 (91%) patients. With the shorter local-VA, the ventricular potential overlapped the atrial potential along a 17.2+/-8.5-mm length of the annulus. No overlap occurred with the opposite wavefront. Reversing the atrial wavefront increased local-AV by >/=15 ms in 32 of 44 (73%) patients. With the shorter local-AV, the atrial potential overlapped the ventricular potential along an 11.9+/-8.9-mm length of the annulus. No overlap occurred with the opposite wavefront. Mapping during longer local-VA or local-AV identified an AP potential in 102 of 114 (89%) patients. Catheter ablation eliminated AP conduction in all 111 patients attempted (median, 1 radiofrequency application in 99 patients with an AP potential versus 4.5 applications without an AP potential). CONCLUSIONS: Reversing the direction of the paced ventricular or atrial wavefront reveals an oblique course in most APs and facilitates localization of the AP potential for catheter ablation.

Characterization of reentrant circuit in macroreentrant right atrial tachycardia after surgical repair of congenital heart disease: isolated channels between scars allow "focal" ablation.

BACKGROUND: The purpose of this study was to characterize the circuit of macroreentrant right atrial tachycardia (MacroAT) in patients after surgical repair of congenital heart disease (SR-CHD). METHODS AND RESULTS: Sixteen patients with atrial tachycardia (AT) after SR-CHD were studied (atrial septal defect in 6, tetralogy of Fallot in 4, and Fontan procedure in 6). Electroanatomic right atrial maps were obtained during 15 MacroATs in 13 patients, focal AT in 1 patient, and atrial pacing in 2 patients without stable AT. A large area of low bipolar voltage (/=2 scars forming narrow channels. Ablation within the channels eliminates MacroAT.

Targeting of glyoxysomal proteins to peroxisomes in leaves and roots of a higher plant.

Higher plants possess several classes of peroxisomes that are present at distinct developmental stages and serve different metabolic roles. To investigate the cellular processes that regulate developmental transitions of peroxisomal function, we analyzed the targeting of glyoxysomal proteins to leaf-type and root peroxisomes. We transferred genes encoding the glyoxysome-specific enzymes isocitrate lyase (IL) and malate synthase into Arabidopsis plants and showed, in cell fractionation and immunogold localization experiments, that the glyoxysomal proteins were imported into leaf-type and root peroxisomes. We next defined the sequences that target IL to peroxisomes and asked whether the same targeting determinant is recognized by different classes of the organelle. By localizing deletion and fusion derivatives of IL, we showed that the polypeptide's carboxyl terminus is both necessary for its transport to peroxisomes and sufficient to redirect a passenger protein from the cytosol to both glyoxysomes and leaf-type peroxisomes. Thus, glyoxysomal proteins are transported into several classes of peroxisomes using a common targeting determinant, suggesting that protein import does not play a regulatory role in determining a peroxisome's function. Rather, the specific metabolic role of a peroxisome appears to be determined primarily by processes that regulate the synthesis and/or stability of its constituent proteins. These processes are specified by the differentiated state of the cells in which the organelles are found.

Expression of a Brassica napus Malate Synthase Gene in Transgenic Tomato Plants during the Transition from Late Embryogeny to Germination.

To study gene regulation during the transition from late embryogeny to germination, we have analyzed the expression of a gene encoding the glyoxylate cycle enzyme malate synthase in transgenic tomato (Lycopersicon esculentum) plants. We have shown that although there are at least four classes of malate synthase genes in Brassica napus L., one gene is expressed at a high level during both late embryogeny and postgermination. Analyses of transgenic tomato plants containing the expressed B. napus gene along with 4.7 and 1.0 kilobase pairs of 5' and 3' flanking sequences, respectively, confirmed that a single gene is expressed at both stages of development. Furthermore, localization studies have shown that mRNA encoded by the B. napus gene is distributed throughout the tissues of a mature embryo but is not detected in the vascular cylinder of a seedling. We conclude that the sequences required to qualitatively regulate the gene correctly over the plant life cycle are present within the transferred gene and/or flanking regions. Moreover, the malate synthase gene is regulated differently during late embryogeny and postgermination in the developing vascular cylinder.