Induction of hypertrophic chondrocyte-like phenotypes by oxidized LDL in cultured bovine articular chondrocytes through increase in oxidative stress

OBJECTIVE

It has been reported that the lectin-like oxidized low-density lipoprotein (Ox-LDL) receptor 1 (LOX-1) is expressed by chondrocytes in osteoarthritis (OA) cartilage and that Ox-LDL binding to LOX-1 increases intracellular oxidative stress in cultured bovine articular chondrocytes (BACs). It was recently demonstrated that reactive oxygen species (ROS) induce hypertrophic differentiation of chondrocytes in the growth plate. It has also been shown that activated chondrocytes in OA have hypertrophic chondrocyte-like phenotypes. The purpose of this study was to determine whether Ox-LDL induces hypertrophic chondrocyte-like phenotypes in BACs.

DESIGN

Changes in type X collagen (COL10) and runt-related transcription factor 2 (Runx2) mRNA expression in BACs after Ox-LDL stimulation were investigated using real-time polymerase chain reaction (PCR). Western blotting and immunofluorescent cell staining were used to investigate changes in protein level. The antioxidant N-acetyl cysteine (NAC) was used to ascertain whether oxidative stress is involved in COL10 and Runx2 expression. We induced LOX-1 knockdown cells using small interfering RNA (siRNA) to examine the receptor specificity of Ox-LDL.

RESULTS

COL10 expression was upregulated by Ox-LDL in a time- and dose-dependent manner. Immunofluorescent staining showed that Ox-LDL increased COL10 production in the extracellular matrix. Ox-LDL-induced upregulation of COL10 was suppressed by pretreatment with NAC and siRNA. Expression of Runx2 was upregulated by Ox-LDL and H(2)O(2), and these effects were suppressed by NAC pretreatment.

CONCLUSION

Ox-LDL binding to LOX-1 induces a hypertrophic chondrocyte-like phenotype through oxidative stress, indicating that Ox-LDL plays a role in the degeneration of cartilage.

[Long term outcome of arterial switch surgery for transposition of the great arteries: evaluation of the reconstruction of the pulmonary artery]

We assessed the effect of reconstructing the pulmonary artery during arterial switch surgery for transposition of the great arteries on late pulmonary stenosis. Sixty-five patients who underwent Lecompte procedure between September 1991 and December 2006 were divided, by the procedure used chronologically to reconstruct the pulmonary artery, into group XP (single pantaloon patch with equine pericardium, n = 11), group P (direct reconstruction, n = 47), and group AP (single pantaloon patch with fresh autopericardium, n = 7). Outcome and pulmonary stenosis on the most recent ultrasound cardiography (UCG) were compared in the 3 groups. The median follow-up was 13, 7.5, and 1.3 years, respectively. Both early and late mortalities were 1.5% (1/65). Although percutaneous trans-pulmonary angioplasty was necessary in 1, 13, and 3 patients, there was 1, 1, and 0 reoperation for pulmonary stenosis in the 3 groups, respectively. Pulmonary stenosis (pulmonary arterial maximum flow velocity > 3 m/sec on UCG) was present in 4 (40%). 14 (30%). and 3 patients (43%). Although there was no significant difference among the 3 procedures in preventing pulmonary stenosis 10 years after arterial switch surgery, direct reconstruction of the pulmonary artery may show a superior outcome, in particular, over 10 years after arterial switch surgery.

Neuroblastoma presenting with dilated cardiomyopathy

We report an infant with neuroblastoma who presented with dilated cardiomyopathy. A 3-month-old girl presented with dilated cardiomyopathy diagnosed as stage III neuroblastoma. Since total resection was impossible, chemotherapy was started. Cardiomyopathy was normalized by improvement of neuroblastoma. The prompt improvement of cardiac function following treatment of neuroblastoma suggested that cardiomyopathy in this patient was caused by the increase in catecholamines secreted by neuroblastoma and that reduction in catecholamines by treatment of neuroblastoma led to improvement in the cardiomyopathy.

Two-dimensional pattern reverse Monte Carlo method for modelling the structures of nano-particles in uniaxial elongated rubbers

Two-dimensional pattern reverse Monte Carlo (2D pattern RMC) analysis is performed to model the structures of nano-particles in uniaxially elongated rubbers using two-dimensional patterns of structure factor of the nano-particles obtained by time-resolved two-dimensional ultra-small angle x-ray scattering. Four spot patterns are observed for a large elongation ratio and the shapes change with increasing elongation ratio. We performed the 2D pattern RMC method for the uniaxial system in order to make a model of the structures from the two-dimensional structure factors. The preliminary results of the 2D pattern RMC analysis of the two-dimensional structure factors of silica particles in a uniaxially elongated styrene-butadiene rubber are presented.

A double-blind dose-ranging study of risedronate in Japanese patients with osteoporosis (a study by the Risedronate Late Phase II Research Group)

To determine the clinical recommended dosage regimen of risedronate for the treatment of involutional osteoporosis in Japanese patients, dose-response relationships for the efficacy and safety of this drug were investigated using a multi-center, randomized, double-blind, parallel group comparative design with four dose levels of risedronate (placebo, 1 mg, 2.5 mg and 5 mg per day). A total of 211 patients diagnosed with involutional osteoporosis according to the criteria proposed by the Japanese Society for Bone and Mineral Research were randomized and received one of the four doses once daily for 36 weeks. All patients were supplemented with 200 mg of calcium daily in the form of calcium lactate. The primary efficacy endpoint was the percent change in bone mineral density of the lumbar spine (L2-L4 BMD) determined by dual-energy X-ray absorptiometry (DXA) from baseline to the time of final evaluation. Changes in biochemical markers of bone turnover and safety profile were also compared. Percent changes in L2-L4 BMD at final evaluation in the placebo, and 1-, 2.5-, and 5-mg risedronate groups were 0.79+/-5.30, 2.71+/-4.93, 5.29+/-3.96, and 5.15+/-4.25% (mean+/-SD), respectively. A linear dose-response relationship was obtained up to a dose of 2.5 mg, whereas no further increase in BMD was observed at 5 mg. The decrease in bone turnover markers, including N-terminal osteocalcin, phosphorus, and urinary deoxypyridinoline, also showed a linear dose-response relationship up to a dose of 2.5 mg. Alkaline phosphatase level decreased linearly up to a dose of 5 mg. Risedronate was well tolerated in this 36-week study with 1- to 5-mg doses. Neither the overall incidence of adverse events nor the percentage of patients without problem in overall safety assessment differed significantly among the dose groups including the placebo group. Based on these results, a once-daily dose of 2.5 mg of risedronate, which is half that used in Caucasians, is recommended for the treatment of involutional osteoporosis in Japanese patients.

Paradoxical enhancement of spinal-cord-evoked potentials rostral and caudal to the site of progressive cord compression in the cat

STUDY DESIGN

Analysis of the sequential waveform changes of the spinal-cord-evoked potentials (SCEPs) associated with progressive cord compression in the cat.

OBJECTIVES

To document the phenomenon of paradoxical enhancement of SCEPs despite conduction abnormalities and to evaluate its possible significance.

SETTING

Kochi Medical School, Kochi, Japan.

METHODS

SCEPs were recorded simultaneously at four serial intervertebral levels, from T6-7 to T9-10 caudal to, and at three serial levels from T2-3 to T4-5 rostral to the compression site at T5-6 following epidural stimulation at L6 in 14 cats.

RESULTS

Caudal to the compression site, the area of negative peak significantly increased toward maximal values of 277+/-36 (mean+/-SE), 151+/-9 and 110+/-4% as compared to the baseline precompression values (100%) at T6-7, T7-8, and T8-9, respectively. Rostral to the compression site, the area of negative peak significantly increased before subsequent deterioration and reached 105+/-2, 106+/-2, and 104+/-2% at T4-5, T3-4, and T2-3, respectively. The onset of negative peak enhancement, recorded either caudal or rostral to the compression site, showed a close temporal correlation (r>0.8, P&<0.001) with that of the prolongation in latency of SCEPs at T2-3.

CONCLUSIONS

A progressive focal conduction block induced by compression of the spinal cord can paradoxically enhance the ascending SCEPs both caudally and, though less consistently, rostrally, representing a warning of the impending risk of paraplegia.

A comparison of the effect of risedronate and etidronate on lumbar bone mineral density in Japanese patients with osteoporosis: a randomized controlled trial

To demonstrate the clinical benefit of 2.5 mg daily risedronate in the treatment of involutional osteoporosis, the effect of risedronate on bone mineral density (BMD) of the lumbar spine was compared with that of etidronate, selected as a representative of the bisphosphonates currently marketed in Japan. In this multicenter, randomized, double-masked, active (etidronate) controlled comparative study, a total of 235 Japanese patients with involutional osteoporosis were randomized to receive either treatment with 2.5 mg/day of risedronate for 48 weeks or intermittent treatment with etidronate (4 cycles of 2 weeks of treatment with 200 mg/day followed by 10-week medication-free periods). All patients received 200 mg of calcium supplement daily in the form of the calcium lactate. Bone mineral density of the lumbar spine (L2-L4 BMD) was determined at 12, 24, 36 and 48 weeks by dual-energy X-ray absorptiometry. The primary endpoint was the percent change in L2-L4 BMD from baseline to the time of final evaluation. Changes in biochemical markers of bone turnover and safety profiles were also compared. A significant increase in L2-L4 BMD was observed at 12 weeks after initiation of therapy in both the risedronate (2.8%) and etidronate (1.8%) groups. The increase in L2-L4 BMD at the time of final evaluation in the risedronate group (4.9%) was significantly greater ( p = 0.002) than that in the etidronate group (3.1%). The changes in bone resorption markers (urinary total deoxypyridinoline and N-terminal telopeptide of type I collagen) from baseline to 48 weeks were -37.6% and -41.3% for risedronate and -22.5% and -26.6% for etidronate, respectively. New vertebral fractures or deterioration of existing fractures were observed in 2.8% (3/106) of the patients in the etidronate group, while no such cases (0/101) were observed in the risedronate group. No significant difference in the incidence of adverse events was found between two treatments. Daily oral risedronate (2.5 mg) exhibited efficacy superior to that of intermittent cyclical etidronate (200 mg) in increasing L2-L4 BMD, and was well tolerated by Japanese patients with involutional osteoporosis.

Chronic active Epstein-Barr virus infection (CAEBV) successfully treated with allogeneic peripheral blood stem cell transplantation

We report a pediatric case of CAEBV and T cell-based Hodgkin's-like disease successfully treated with allo PBSCT from an HLA-matched sibling. The diagnosis of CAEBV was made from clinical signs and the presence of the EBV genome in PBMC and tumor cells. Conditioning with busulfan (BU) + etoposide (VP16) + cyclophosphamide (CY) was effective and well tolerated. EBV was totally eradicated by 3 months after allo PBSCT. Although she suffered from chronic GVHD of the liver, she has been well and free of disease for 47 months since PBSCT. We suggest allo PBSCT for CAEBV as a potent therapeutic strategy for eradication of the EBV genome and allowing immunological reconstitution.

Effect of short-term low-intensity exercise on insulin sensitivity, insulin secretion, and glucose and lipid metabolism in non-obese Japanese type 2 diabetic patients

The aim of the present study was to investigate the effects of short-term physical exercise that did not change body mass on insulin sensitivity, insulin secretion, and glucose and lipid metabolism in 39 non-obese Japanese type 2 diabetic patients. Insulin sensitivity and insulin secretion were estimated with homeostasis model assessment insulin resistance (HOMA-IR) and HOMA-B-cell function proposed by Matthews et al., respectively. All patients were hospitalized and were engaged in low-intensity exercise that consisted of walking and dumbbell exercise for successive 7 days. There were no changes in hospital diet and the dose of any medications used throughout the study. Fasting glucose, insulin, and lipids were measured before and after exercise. After exercise, serum triglyceride levels significantly decreased, but no significant changes were observed in total and HDL cholesterol concentrations. Fasting glucose, insulin, and HOMA-IR levels significantly decreased after exercise, but HOMA-B-cell function did not change during the study. There was no significant difference between BMI levels before and after exercise. From these results, it can be concluded that short-term (7 days) low-intensity physical exercise combined with hospital diet reduces serum triglycerides, insulin resistance, and fasting glucose levels without affecting BMI in non-obese Japanese type 2 diabetic patients.

[Orthopaedic management for severe osteoporosis]

In severe-osteoporotic patients with vertebral fractures, back pain is usually a major complaint and can be acute or chronic. Acute back pain is usually due to a recent vertebral fracture. Chronic pain may be due to vertebral fractures per se or could result from kyphotic or scoliotic changes in the spine, with inappropriate stretching of ligaments, facet joint capsules and paraspinal muscles. Treatment of vertebral fractures must focus on relief of pain and prevention of further fractures. In many patients, significant symptomatic relief can be achieved through physical therapy, rehabilitation, and bracing. Muscle-strengthening and weight-loading exercises could be needed for prevention of further bone loss and fractures.

A defect in central tolerance in NOD mice

The predisposition of nonobese diabetic (NOD) mice to develop autoimmune disease is usually attributed to defects in peripheral tolerance mechanisms. Here, evidence is presented that NOD mice display a defect in central tolerance (negative selection) of thymocytes. Impaired central tolerance in NOD mice was most prominent in a population of semi-mature thymocytes found in the medulla. The defect was apparent in vivo as well as in vitro, was independent of IAbetag7 expression and affected both Fas-dependent and Fas-independent pathways of apoptosis; for Fas-dependent apoptosis, the defective tolerance of NOD thymocytes correlated with the strong T cell receptor-mediated up-regulation of caspase 8-homologous FLICE (Fas-associated death-domain-like interleukin 1beta-converting enzyme)-inhibitory protein. In light of these findings, disease onset in NOD mice may reflect defects in central as well as peripheral tolerance.