Risk factors associated with the occurrence of hip fracture in Japanese patients with rheumatoid arthritis: a prospective observational cohort study

Risk factors associated with the occurrence of hip fracture in Japanese patients with rheumatoid arthritis (RA) were evaluated in a prospective, observational cohort study. Physical disability, advanced age, history of total knee replacement (TKR), and low body mass index (BMI) appear to be associated with the occurrence of hip fracture.

INTRODUCTION

This study seeks to evaluate the association between potential risk factors and the occurrence of hip fractures in Japanese RA patients.

METHODS

A total of 9,720 patients (82.1% female; mean age, 55.7 years) with RA were enrolled in a prospective observational study from 2000 to 2010. Self-reported hip fractures were verified using patient medical records. Cox proportional hazards models were used to analyze independent contributions of various risk factors to hip fracture occurrence.

RESULTS

During a mean follow-up of 5.2 years, 152 patients reported 152 hip fractures. Among these patients, 97 hip fractures in 97 patients (15 males, 82 females) were verified with medical records. Japanese version of the Health Assessment Questionnaire (J-HAQ) disability score [per 1 score, hazard ratio (HR), 2.64; 95% confidence interval (CI), 1.94-3.58], age (per 10 years; HR, 1.53; 95% CI, 1.25-1.87), history of TKR (HR, 3.75; 95% CI, 1.57-8.96), and BMI (per 1 kg/m2, HR, 0.92; 95% CI, 0.86-0.99) were significantly associated with hip fractures. Among the scores on the eight domains of the J-HAQ, J-HAQ (arising) (HR, 1.74; 95% CI, 1.28-2.36) and J-HAQ (hygiene) (HR, 1.58; 95% CI, 1.11-2.24) were significantly correlated with the occurrence of hip fracture.

CONCLUSIONS

High J-HAQ disability score, advanced age, history of TKR, and low BMI appear to be associated with the occurrence of hip fractures in Japanese RA patients. Among the eight domains of the J-HAQ, arising and hygiene disabilities appear to be correlated with the occurrence of hip fractures in this patient population.

Serological evidence of infection with hepatitis E virus among wild Yezo-deer, Cervus nippon yesoensis, in Hokkaido, Japan

In this study, 520 serum samples from Yezo-deer in the Hidaka district, Hokkaido, Japan were examined by enzyme-linked immunosorbent assay to investigate whether the animals were infected with hepatitis E virus (HEV). The distribution of optical density values showed a bimodal pattern and 181 samples (34.8%) were deemed to be antibody-positive against HEV. At least five (2.8%) of the positive sera gave specific bands by Western blot analysis. An age-dependent increase in prevalence of the antibodies was found among the animals. These findings indicate that Yezo-deer are a possible host for HEV infection. To avoid the risk of becoming HEV infected, the consumption of raw Yezo-deer meat must be prohibited.

Low disease activity state with corticosteroid may not represent 'true' low disease activity state in patients with rheumatoid arthritis

OBJECTIVE

Corticosteroids constitute one of the most common treatments of RA. The purpose of this study is to investigate whether long-term corticosteroid use suppresses the progression of disability in RA patients with low disease activity state.

METHODS

Data collected from a large observational cohort of RA patients at our institution were analysed for 214 RA patients whose disease activity score (DAS) 28 and HAQ were available consecutively from October 2000 to October 2004. All 214 patients had average DAS 28 <3.2, meaning only those who had well-controlled RA disease activity were chosen as subjects. The subjects were divided into steroid users who received continuous corticosteroids every month and non-steroid users who did not receive consecutive corticosteroids continuously every month.

RESULTS

Fifty-five patients (25.7%) were corticosteroid users and 159 (74.3%) were non-users. Average prednisolone for the former group was 4.2 mg/day. No significant differences were observed among baseline variables and RA disease activity variables. However, for steroid users, HAQ progressively worsened with time and for non-steroid users, HAQ progressively improved.

CONCLUSIONS

Although DAS 28 and other variables may suggest well-controlled RA disease activity, functional capacity of patients on low-dose corticosteroids deteriorated. Thus, low disease activity state with corticosteroid may not represent the 'true' low disease activity state. Along with the achievement of a low disease activity state, long-term efficacy, prognosis, and the quality of remission need to be also considered in the tight control of RA activity.

Efficient management of rheumatoid arthritis significantly reduces long-term functional disability

OBJECTIVES

The aim of this study was to examine the effect of efficient management of rheumatoid arthritis (RA) in relation to disability levels in a large cohort of patients with RA over a period of 3 years.

METHODS

We studied 2775 patients with RA who had continuous enrolment for at least 3 years from 7511 patients with RA enrolled in an observational cohort study (Institute of Rheumatology, Rheumatoid Arthritis (IORRA)) from October 2000 to April 2005. The 28-joint Disease Activity Scores (DAS28) were calculated at 6 month intervals for all the patients and a value <2.6 was considered as a tight control. We have set up a new variable for each patient, "Avg-Dscore", based on the transition of each patient's DAS28 value, taking the threshold level of 2.6 into consideration. The "Avg-DAS28" is the average of DAS28 values over all the phases. Functional disability status was assessed by J-HAQ, the validated Japanese version of the Health Assessment Questionnaire (HAQ). The relationship of "Avg-Dscore" and "Avg-DAS28" with the functional disability level was determined using Spearman correlation coefficients and multiple linear regression models.

RESULTS

The baseline features of these 2775 patients were: female 83.7%, mean age 56.8 years, mean RA duration 9.5 years, mean initial DAS28 4.0, mean initial J-HAQ score 0.79, and mean final J-HAQ score 0.86. There was a statistically significant correlation between "Avg-DAS28" and final J-HAQ score (r = 0.57, p<0.001), indicating that tighter disease control has significant association with lower disability levels. A similar relationship was observed between "Avg-Dscore" and final J-HAQ score (r = 0.47, p<0.001). Multiple linear regression analysis, after adjusting for all the covariates, revealed that "Avg-Dscore" and "Avg-DAS28" were the most significant factors contributing to final J-HAQ score, and confirmed the strong relationship between disease activity and functional disability.

CONCLUSIONS

In patients with RA efficient disease management, by maintaining the DAS28 values at a level under 2.6, has significant association with improving functional capability. The threshold DAS28 level of 2.6 may be useful in developing targeted treatment guidelines for patients with RA.

What's in season for rheumatoid arthritis patients? Seasonal fluctuations in disease activity

OBJECTIVES

To examine whether a seasonal fluctuation exists with rheumatoid arthritis (RA) activity and to analyse seasonal effects of varying components that express disease activity in RA patients.

METHODS

A group of 1665 RA patients (mean age 57.2 yrs, mean disease duration 9.9 yrs) whose data were available for 10 consecutive phases from a large observational cohort study conducted at our institution from October 2000 to April 2005, bi-annually, were evaluated. Ten criteria were analysed to assess RA disease activity.

RESULTS

All criteria revealed decrease in disease activity during fall and increase in disease activity during spring, except for the physician's global assessment of disease activity in which significant differences were not observed between the two seasons.

CONCLUSIONS

We found definite seasonal differences in RA patients, both subjectively and objectively. RA disease activity was higher in spring and lower during fall. Seasonal changes may play an important role in evaluating disease activity of RA patients and should be taken into account when examining these patients.

Increased risk of tuberculosis in patients with rheumatoid arthritis in Japan

OBJECTIVE

To determine the risk for tuberculosis infection in patients with rheumatoid arthritis before the anti-cytokine era in Japan.

PATIENTS AND METHODS

A database of a single-institute-based large observational cohort study for rheumatoid arthritis at the Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan, was analysed. Information on the history of tuberculosis infection was collected by patient self-reporting during April and October 2003. The age-adjusted incidence rate and relative risk for tuberculosis infection were investigated.

RESULTS

Among 5044 patients with rheumatoid arthritis, 483 (9.6%) patients claimed to have a history of tuberculosis infection before October 2002. The frequency of history of tuberculosis increased according to the age of the patient. Four cases of new-onset tuberculosis were identified among 5544 patients with rheumatoid arthritis during 1 year. The age-adjusted incidence of tuberculosis was 42.4/100,000 patients. The relative risk for tuberculosis was 3.21 (95% confidence interval (CI) 1.21 to 8.55), and that of men and women was 10.59 (95% CI 3.42 to 32.78) and 1.41 (95% CI 0.2 to 10), respectively.

CONCLUSION

There was an increased risk of tuberculosis infection in Japanese patients with rheumatoid arthritis, especially in male patients before the introduction of anti-tumour necrosis factor treatment. These data should form the basis for the risk management of anti-cytokine treatment in Japan.

Haplotype analysis revealed no association between the PTPN22 gene and RA in a Japanese population

OBJECTIVE

The protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene is a member of the PTPs that negatively regulate T-cell activation. A missense single nucleotide polymorphism (SNP) in the PTPN22 gene known as R620W was recently reported to be associated with several autoimmune diseases including rheumatoid arthritis (RA). The association was confirmed repeatedly in the populations of North European ancestry. However, the SNP was reported to be non-polymorphic in the Asian populations. Because the gene confers an impact on autoimmune diseases, we attempt to explore an association between PTPN22 gene and RA in a Japanese population without restricting to the SNP, R620W.

METHODS

We studied 1128 RA patients and 455 controls. In addition to the SNP, R620W, we selected eight testing SNPs spanning 45 kb over the PTPN22 gene using the International HapMap Project. Genotyping was performed using the TaqMan fluorogenic 5' nuclease assay. Associations between RA and each of the SNPs were estimated by the Fisher's exact test. Haplotype was constructed using the expectation-maximization algorithm.

RESULTS

R620W was not polymorphic enough in both the patients and the controls, and was therefore excluded from further analysis. Each allele frequency for the eight other SNPs in both groups was compared and no association was detected. Haplotype analysis also revealed that PTPN22 gene was not associated with RA in a Japanese population.

CONCLUSION

We found no association between PTPN22 and RA in a Japanese population. The result suggests that the PTPN22 gene is associated with RA only in a specific ethnic group.

Mechanical responses of a compliant electrospun poly(l-lactide-co-ε-caprolactone) small-diameter vascular graft

To design a "mechano-active" small-diameter artificial vascular graft, a tubular scaffold made of elastomeric poly(L-lactide-co-epsilon-caprolactone) fabrics at different wall thicknesses was fabricated using an electrospinning (ELSP) technique. The wall thickness of the fabricated tube (inner diameter; approximately 2.3-2.5 mm and wall thickness; 50-340 microm) increased proportionally with ELSP time. The wall thickness dependence of mechanical responses including intraluminal pressure-induced inflation was determined under static and dynamic flow conditions. From the compliance-related parameters (stiffness parameter and diameter compliance) measured under static condition, the smaller the wall thickness, the more compliant the tube. Under dynamic flow condition (1 Hz, maximal/minimal pressure of 90 mmHg/45 mmHg) produced by a custom-designed arterial circulatory system, strain, defined as the relative increase in diameter per pulse, increased with the decrease in wall thickness, which approached that of a native artery. Thus, a mechano-active scaffold that pulsates synchronously by responding to pulsatile flow was prepared using elastomeric PLCL as a base material and an ELSP technique.

Signal intensity changes in T2-weighted MR image of the human trapezius muscle upon cold pressor stimulation

OBJECTIVE

The ability to measure hemodynamics of skeletal muscle proper is one of the major goals for muscle pain researchers. The aim of the present study was to evaluate the ability of signal intensity (SI) in T2-weighted trapezius muscle magnetic resonance imaging (MRI) to detect intramuscular hemodynamic changes during cold pressor stimulation (CPS).

MATERIALS AND METHODS

Fifteen healthy volunteers (mean age, 25.9+/-2.1 years) participated in this study. T2-weighted MRI was acquired using a 1.5 tesla MR unit with a body array coil. The slice level was set perpendicular to the muscle long axis at the mid-point of the horizontal portion of the right trapezius muscle. Cold pressor stimulation (4 degrees C) was applied to each subject's right foot and ankle for 2 min. The SI changes were recorded continuously for 7 min before, 2 min during, and 6 min after withdrawal of cold pressor stimulation. Six of these subjects also underwent a mock-CPS trial.

RESULTS

The mean SI level in T2-weighted trapezius muscle MRI significantly increased during CPS (P<0.0001, one way repeated measure ANOVA) and returned to the baseline level after cold pressor withdrawal. No statistically significant signal changes were observed across the mock-CPS trial subjects. These findings are identical to the cold pressor-induced hemodynamic changes documented in the trapezius muscle by near-infrared spectroscopy evaluation.

CONCLUSIONS

SI measurement in T2-weighted trapezius muscle MRI is sufficiently sensitive to detect intramuscular hemodynamic changes during CPS.

Membrane-associated guanylate kinase with inverted orientation (MAGI)-1/brain angiogenesis inhibitor 1-associated protein (BAP1) as a scaffolding molecule for Rap small G protein GDP/GTP exchange protein at tight junctions

BACKGROUND

Membrane-associated guanylate kinase (MAGUK) with inverted orientation (MAGI)-1/brain angiogenesis inhibitor 1-associated protein (BAP1), is a member of the MAGUK family that has multiple PDZ domains and interacts with many transmembrane proteins, including receptors and channels, through these domains. MAGI-1/BAP1 is ubiquitously expressed and localized at tight junctions in epithelial cells. It is an isoform of the neurone-specific synaptic scaffolding molecule (S-SCAM), which is known to interact with NMDA receptors and neuroligins. We have recently found that S-SCAM also interacts with a signalling molecule, a GDP/GTP exchange protein (GEP) that is specific for Rap1 small G protein, Rap GEP, which has also recently been referred to as RA-GEF/PDZ-GEFI/CNras-GEF. In this study, we have examined whether MAGI-1/BAP1 also interacts with and serves as a scaffolding molecule for Rap GEP at tight junctions in epithelial cells.

RESULTS

MAGI-1/BAP1 similarly interacted with Rap GEP in cell-free and intact cell systems. A Northern blot analysis revealed that Rap GEP was expressed in most tissues examined. However, neither postsynaptic density (PSD)-95/synapse-associated protein (SAP) 90 (another member of the MAGUK family) nor SAP97/human discs-large tumour suppressor gene product (another ubiquitously expressed MAGUK localizing to adherens junctions in epithelial cells and the isoform of PSD-95/SAP90) interacted with Rap GEP.

CONCLUSION

These results indicate that MAGI-1/BAP1 serves as a scaffolding molecule for Rap GEP at tight junctions in epithelial cells.

Importance of spatial activation of Cdc42 and rac small G proteins by frabin for microspike formation in MDCK cells

BACKGROUND

Frabin is an actin filament (F-actin)-binding protein that shows GDP/GTP exchange activity for Cdc42 small G protein (Cdc42). Frabin furthermore induces indirect activation of Rac small G protein (Rac) in intact cells. We have recently shown that in nonepithelial cells, frabin induces the formation of both filopodia- and lamellipodia-like processes through the activation of Cdc42 and Rac, respectively. In epithelial cells such as MDCK cells, Cdc42 and Rac regulate cell-cell adherens junctions (AJs) via the accumulation of F-actin and E-cadherin, although neither Cdc42 nor Rac induces the formation of filopodia or lamellipodia. In this study, we have examined the effects of frabin on the reorganization of the actin cytoskeleton in MDCK cells.

RESULTS

Frabin induces the formation of microspikes at the basal area of the lateral membranes through the activation of Cdc42 and Rac in MDCK cells, although a dominant active mutant of Cdc42 or Rac alone, or both, did not induce the formation of microspikes. Furthermore, frabin weakly increased the accumulation of F-actin and E-cadherin at cell-cell AJs and the formation of stress fibres through the activation of Cdc42 and Rac, under conditions where the dominant active mutant of Cdc42 or Rac markedly showed these effects. The Cdc42- and Rac-induced formation of stress fibres was dependent on the activation of Rho small G protein.

CONCLUSION

These results indicate that the frabin-dependent spatial activation of Cdc42 and Rac is important for the formation of microspikes.

Development of bacterial expression system with high yield of CYP3A7, a human fetus-specific form of cytochrome P450

In an E. coli expression system for human cytochrome P450 3A7 (CYP3A7), holo-CYP3A7 was not expressed as judged by CO-difference spectra, although apo-CYP3A7 was clearly detected by Western blot analysis. Unlike CYP3A7, CYP3A4 was expressed efficiently as a hemoprotein in E. coli transformed with a CYP3A4 expression plasmid. To achieve the high yield of the holo-CYP3A7 in E. coli, we examined a causal residue(s) preventing the expression of the holo-CYP3A7 using the chimeric gene of CYP3A4 with CYP3A7. It was found that the region between residues 405 and 503 of CYP3A7 was responsible for the prevention of the holo-CYP3A7 expression in E. coli. Among amino acids examined, substitution of Thr at position 485 in CYP3A7 with Pro, which is at the corresponding position of CYP3A4, resulted in an increase in the amount of holo-CYP3A7. The Thr residue was adjacent to the heme-binding region of CYP3A7. Thus, it appeared that the incorporation of heme into CYP3A7 was possibly affected by this particular amino acid residue. Moreover, holo-CYP3A7 was expressed efficiently when CYP3A7 was co-expressed with molecular chaperone GroEL, known to assist the correct folding of unfolded proteins. Dehydroepiandrosterone 16alpha-hydroxylation was catalyzed by CYP3A7 expressed in the presence of GroEL.

Low-cost soft-copy display accuracy in the detection of pulmonary nodules by single-exposure dual-energy subtraction: comparison with hard-copy viewing

This study endeavored to clarify the usefulness of single-exposure dual-energy subtraction computed radiography (CR) of the chest and the ability of soft-copy images to detect low-contrast simulated pulmonary nodules. Conventional and bone-subtracted CR images of 25 chest phantom image sets with a low-contrast nylon nodule and 25 without a nodule were interpreted by 12 observers (6 radiologists, 6 chest physicians) who rated each on a continuous confidence scale and marked the position of the nodule if one was present. Hard-copy images were 7 x 7-inch laser-printed CR films, and soft-copy images were displayed on a 21-inch noninterlaced color CRT monitor with an optimized dynamic range. Soft-copy images were adjusted to the same size as hard-copy images and were viewed under darkened illumination in the reading room. No significant differences were found between hard- and soft-copy images. In conclusion, the soft-copy images were found to be useful in detecting low-contrast simulated pulmonary nodules.

Bni1p regulates microtubule-dependent nuclear migration through the actin cytoskeleton in Saccharomyces cerevisiae

The RHO1 gene encodes a yeast homolog of the mammalian RhoA protein. Rho1p is localized to the growth sites and is required for bud formation. We have recently shown that Bni1p is one of the potential downstream target molecules of Rho1p. The BNI1 gene is implicated in cytokinesis and the establishment of cell polarity in Saccharomyces cerevisiae but is not essential for cell viability. In this study, we screened for mutations that were synthetically lethal in combination with a bni1 mutation and isolated two genes. They were the previously identified PAC1 and NIP100 genes, both of which are implicated in nuclear migration in S. cerevisiae. Pac1p is a homolog of human LIS1, which is required for brain development, whereas Nip100p is a homolog of rat p150(Glued), a component of the dynein-activated dynactin complex. Disruption of BNI1 in either the pac1 or nip100 mutant resulted in an enhanced defect in nuclear migration, leading to the formation of binucleate mother cells. The arp1 bni1 mutant showed a synthetic lethal phenotype while the cin8 bni1 mutant did not, suggesting that Bni1p functions in a kinesin pathway but not in the dynein pathway. Cells of the pac1 bni1 and nip100 bni1 mutants exhibited a random distribution of cortical actin patches. Cells of the pac1 act1-4 mutant showed temperature-sensitive growth and a nuclear migration defect. These results indicate that Bni1p regulates microtubule-dependent nuclear migration through the actin cytoskeleton. Bni1p lacking the Rho-binding region did not suppress the pac1 bni1 growth defect, suggesting a requirement for the Rho1p-Bni1p interaction in microtubule function.