RESUMO
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.
Assuntos
Atividades Cotidianas , Internacionalidade , Dor Lombar/epidemiologia , Dor Musculoesquelética/epidemiologia , Adulto , Feminino , Humanos , Dor Lombar/fisiopatologia , Masculino , Pessoa de Meia-Idade , Dor Musculoesquelética/fisiopatologia , Doenças Profissionais/epidemiologia , Doenças Profissionais/fisiopatologia , Prevalência , Análise de Regressão , Fatores de Risco , Adulto JovemRESUMO
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.
Assuntos
Viés de Atenção/fisiologia , Terapia Cognitivo-Comportamental/métodos , Potenciais Evocados/fisiologia , Síndrome do Intestino Irritável/psicologia , Síndrome do Intestino Irritável/terapia , Feminino , Humanos , Síndrome do Intestino Irritável/fisiopatologia , Masculino , Adulto JovemRESUMO
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.
RESUMO
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.
Assuntos
Nó Atrioventricular/fisiopatologia , Estimulação Cardíaca Artificial , Sistema de Condução Cardíaco/fisiopatologia , Adolescente , Adulto , Idoso , Ablação por Cateter , Criança , Pré-Escolar , Feminino , Átrios do Coração/fisiopatologia , Ventrículos do Coração/fisiopatologia , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
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 (=0.5 mV) involved most of the free wall in all patients and contained 2 to 7 dense scars or lines of double potentials, forming 29 narrow channels (width =2.7 cm) between scars in all but 1 patient, who had a single scar and only focal AT. All 15 MacroATs were propagated through narrow channels. Ablation within the channel eliminated all 15 MacroATs with 1 to 3 (median 1) radiofrequency applications. Ablation was performed in 9 other channels identified during MacroAT (5 patients) and in 5 channels identified during atrial pacing (2 patients). Conduction block was obtained across 28 of 29 channels. After ablation, reproducible sustained right AT was not induced in any patient. During follow-up (median 13.5 months), new MacroATs, atrial fibrillation, or palpitations occurred in 3 of 16 patients. CONCLUSIONS: MacroAT after SR-CHD requires a large area of low voltage containing >/=2 scars forming narrow channels. Ablation within the channels eliminates MacroAT.
Assuntos
Comunicação Interatrial/cirurgia , Taquicardia/etiologia , Adulto , Flutter Atrial , Função do Átrio Direito , Ablação por Cateter , Eletrofisiologia , Feminino , Seguimentos , Técnica de Fontan , Comunicação Interatrial/complicações , Comunicação Interatrial/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Taquicardia/fisiopatologia , Taquicardia/cirurgiaAssuntos
Núcleo Celular , DNA/análise , Citometria por Imagem/métodos , Lasers , Animais , Apoptose , Cricetinae , Cricetulus , Citometria por Imagem/instrumentaçãoRESUMO
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.
Assuntos
Arabidopsis/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/ultraestrutura , Sequência de Bases , DNA Complementar/genética , Genes de Plantas , Isocitrato Liase/genética , Isocitrato Liase/metabolismo , Malato Sintase/genética , Malato Sintase/metabolismo , Microcorpos/metabolismo , Microcorpos/ultraestrutura , Microscopia Imunoeletrônica , Dados de Sequência Molecular , Proteínas de Plantas/metabolismo , Plantas Geneticamente ModificadasRESUMO
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.