Peritoneal Dialysis-Related Peritonitis Caused by Streptococcus oralis.

A 77-year-old man developed peritoneal dialysis-related peritonitis caused by Streptococcus oralis, a rare pathogen causing the disease. The infection, which was not controlled by one-week intraperitoneal administration of cefazolin and ceftazidime, was cured only after switching to two-week intravenous administration of cefazolin and ceftazidime. The patient had no major dental disease or recent history of dental intervention. This case suggests that S. oralis might cause peritoneal dialysis-related peritonitis with persistent systemic inflammation via an extra-oral infection route. The clinical course is discussed along with a review of the literature.

A new classification of anterior talofibular ligament injuries based on ultrasonography findings.

BACKGROUND: Ultrasonography (US) has become a useful tool in the evaluation of thickness and continuity of damaged ligaments owing to the rapid advances in its performance and availability. Furthermore, US examination is economical and can be undertaken in a more timely manner than MRI, as it can be performed during the first patient visit. It is also likely to be more accurate than the traditional method of palpating ligaments to diagnose possible injury. The anterior talofibular ligament (ATFL) is most frequently injured of the lateral ankle ligaments and easy to depict on US. This study aimed to assess the treatment outcomes of lateral ankle ligament injuries using a new classification for ATFL injuries based on US findings. METHODS: A total of 140 acute lateral ankle ligament injuries in 132 patients (46 men, 86 women) treated non-operatively were evaluated retrospectively. The average age of the patients was 17.8 years (range, 7-57 years). Patients with a complaint of lateral ankle injury were examined using US, and the anterior talofibular ligament damage was classified into 5 types depending on the type of the injury. The treatment method was selected based on the ultrasonographic classification, and the clinical results were assessed by original evaluation and compared between treatment methods and classification types. RESULTS: A Good or Excellent treatment result was obtained in 133 out of 140 injuries (95.0%). Significant differences were observed in the distribution of treatment methods by injury type (P < 0.001), and the distribution of outcomes was significantly different from the uniform distribution (P < 0.001). Our findings demonstrate that the ultrasonographic classification proposed in this study can be used to determine the appropriate treatment resulting in good outcomes for all types of anterior talofibular ligament damage. CONCLUSION: Visualization of injured ligaments using US may introduce a novel approach of rating and treating ligament injuries.

Common variants in DVWA on chromosome 3p24.3 are associated with susceptibility to knee osteoarthritis.

Susceptibility to osteoarthritis, the most common human arthritis, is known to be influenced by genetic factors. Through a genome-wide association study using approximately 100,000 SNPs, we have identified a previously unknown gene on chromosome 3p24.3, DVWA, which is associated with susceptibility to knee osteoarthritis. Expressed specifically in cartilage, DVWA encodes a 276-amino-acid protein with two regions corresponding to the von Willebrand factor type A domain (VWA domain). Several DVWA SNPs are significantly associated with knee osteoarthritis in two independent Japanese case-control cohorts. This association was replicated in a Japanese population cohort and a Han Chinese case-control cohort (combined P = 7.3 x 10(-11)). DVWA protein binds to beta-tubulin, and the binding is influenced by two highly associated missense SNPs (rs11718863 and rs7639618) located in the VWA domain. The Tyr169-Cys260 isoform of DVWA, which is overrepresented in knee osteoarthritis, showed weaker interaction. Our findings reveal a new paradigm for study of osteoarthritis etiology and pathogenesis.

A functional SNP in EDG2 increases susceptibility to knee osteoarthritis in Japanese.

Osteoarthritis (OA) is the most common form of arthritis and is characterized by the gradual loss of articular cartilage. Several OA-susceptibility genes have been identified; however, there are few pharmaceutical targets that can be targeted with small-molecule compounds. To investigate whether a susceptibility gene for OA exists among G-protein-coupled receptors (GPCRs), we performed a stepwise association study for 167 single nucleotide polymorphisms (SNPs) in 44 GPCR genes that were present in cartilage. Through the stepwise association study, an SNP located in the promoter region of EDG2 [endothelial differentiation, lysophosphatidic acid (LPA) GPCR, 2] (-2,820G/A; rs10980705) showed significant association with knee OA in two independent populations (pooled P = 2.6 x 10(-5)). Luciferase and electrophoretic mobility shift assays indicate that this SNP exerts an allelic difference on transcriptional activity and DNA binding in synovial cells, with the susceptibility allele showing increased activity and binding. EDG2 encodes an LPA receptor dominantly expressed in the synovium. The LPA receptor increased the expression of inflammatory cytokines and matrix metalloproteases in synovial cells. Our findings suggest that the LPA-EDG2 signal is involved in the pathogenesis of OA via catabolic process.

Factors influencing range of motion after contemporary total knee arthroplasty.

A detailed analysis of 219 total knee arthroplasties performed with a single implant design was performed. Factors significantly affecting the postoperative range of motion of total knee arthroplasties 2 years after surgery included preoperative diagnosis and preoperative range of motion. Sex, age, body mass index, femoral component size, posterior cruciate ligament status, or fixed vs mobile bearing design did not correlate with knee range of motion 2 years postoperatively.

A functional single nucleotide polymorphism in the core promoter region of CALM1 is associated with hip osteoarthritis in Japanese.

Osteoarthritis (OA), a common skeletal disease, is a leading cause of disability among the elderly populations. OA is characterized by gradual loss of articular cartilage, but the etiology and pathogenesis of OA are largely unknown. Epidemiological and genetic studies have demonstrated that genetic factors play an important role in OA. To identify susceptibility genes for OA, we performed a large-scale, case-control association study using gene-based single nucleotide polymorphisms (SNPs). In two independent case-control populations, we found significant association (P=9.8x10(-7)) between hip OA and a SNP (IVS3-293C>T) located in intron 3 of the calmodulin (CaM) 1 gene (CALM1). CALM1 was expressed in cultured chondrocytes and articular cartilage, and its expression was increased in OA. Subsequent linkage-disequilibrium mapping identified five SNPs showing significant association equivalent to IVS3-293C>T. One of these (-16C>T) is located in the core promoter region of CALM1. Functional analyses indicate that the susceptibility -16T allele decreases CALM1 transcription in vitro and in vivo. Inhibition of CaM in chondrogenic cells reduced the expression of the major cartilage matrix genes Col2a1 and Agc1. These results suggest that the transcriptional level of CALM1 is associated with susceptibility for hip OA through modulation of chondrogenic activity. Our findings reveal the CALM1-mediated signaling pathway in chondrocytes as a novel potential target for treatment of OA.

An aspartic acid repeat polymorphism in asporin inhibits chondrogenesis and increases susceptibility to osteoarthritis.

Osteoarthritis is the most common form of human arthritis. We investigated the potential role of asporin, an extracellular matrix component expressed abundantly in the articular cartilage of individuals with osteoarthritis, in the pathogenesis of osteoarthritis. Here we report a significant association between a polymorphism in the aspartic acid (D) repeat of the gene encoding asporin (ASPN) and osteoarthritis. In two independent populations of individuals with knee osteoarthritis, the D14 allele of ASPN is over-represented relative to the common D13 allele, and its frequency increases with disease severity. The D14 allele is also over-represented in individuals with hip osteoarthritis. Asporin suppresses TGF-beta-mediated expression of the genes aggrecan (AGC1) and type II collagen (COL2A1) and reduced proteoglycan accumulation in an in vitro model of chondrogenesis. The effect on TGF-beta activity is allele-specific, with the D14 allele resulting in greater inhibition than other alleles. In vitro binding assays showed a direct interaction between asporin and TGF-beta. Taken together, these findings provide another functional link between extracellular matrix proteins, TGF-beta activity and disease, suggesting new therapeutic strategies for osteoarthritis.

Experimental study on thermal welding for the knee meniscal white zone.

It is difficult to repair tears of the meniscus at the white zone by suturing. We considered that there might be an optimal tissue welding temperature when thermally welding the meniscal white zone, so we conducted a thermal welding experiment using bovine and human menisci. The samples prepared after thermal welding were investigated by measuring the tensile strength, analyzing the histological findings of the welded portion and the meniscal parenchyma, and conducting biochemical analyses. In the experiment using human menisci, histological findings were investigated using transmission electron microscopy (TEM). As the findings on the welded tissue in the white zone of the bovine meniscus indicated positive results at 63 degrees C and 69 degrees C, the experiments using human meniscal white zone were conducted at these two temperatures. The highest tensile strength after thermal welding of the human meniscal white zone was 101.4 +/- 2.6 g/cm(2) at 63 degrees C. Although there were no significant differences in the amount of pyridinoline per unit collagen weight [Pyr/Hpr (%)] in the human meniscus after thermal welding between the control group and various temperature groups (55 degrees C, 63 degrees C, 69 degrees C, 75 degrees C), the amount of pyridinoline per unit of collagen weight tended to decline as the welding temperature increased. According to the TEM findings, the internal structure of the nuclei of the cells was preserved in the 63 degrees C group, whereas cells were denatured inside the nuclei in the 69 degrees C group. They exhibited necrosis, making cell regeneration difficult. Therefore, it seems feasible that thermal welding at 63 degrees C can repair tears in the human meniscal white zone.

Bilateral plica synovialis mediopatellaris syndrome: a case report.

The plica synovialis mediopatellaris, a so-called shelf, is found in 20%-50% of normal knees. A shelf syndrome with pain or functional injury is uncommon, however, and cases that occur during the adolescent growth phase are rare. We report a rare case of a bilateral shelf syndrome that developed simultaneously in both knees. The patient was a 13-year-old girl who presented with bilateral knee pain and severely decreased range of motion. The symptoms were not alleviated after internal therapy, so arthroscopy was performed. It showed a white hypertrophied synovialis mediopatellaris, a shelf from the suprapatellar pouch, in both knees. The shelf had an opening between the free margin and the insertion point, giving rise to a synovialis mediopatellaris with a detached structure (type D according to the Sakakibara classification). The cause of the pain was thought to be impingement of the synovialis mediopatellaris. The shelf was ablated by arthroscopy using a holmium-YAG laser. Since the patient was a 13-year-old girl in the growth phase, it is possible that the growth resulted in tension on the shelf remnant bilaterally, intruding into the medial aspect of the patellofemoral joint and increasing the tension, resulting in the symptoms reported.

Effects of drug treatment on bone strength and structural changes with aging: an experimental study in rats.

The purpose of the present study was to evaluate the profiles of the bone strength of rats treated from infancy with various drugs. Young female Sprague-Dawley rats were classified into five groups according to the composition of their diets. They underwent resection of their femurs for a three-point flexion test and an impaction test at 6, 8, 12, and 16 months of age. A microcomputed tomography unit was used to evaluate the microstructure of their femoral condyles at 16 months of age. The diet given to the rats in the control group contained 0.5% Ca. The rats in groups A, B, C, and D were placed on the following regimens, respectively: vitamin K mixed diet, vitamin D oral administration, 1.8% Ca-fortified diet, and 1.8% Ca-fortified diet plus vitamin K and vitamin D. In the impaction tests conducted on the rats at each age, the results from groups A and B were nearly the same as those from the control group. At 16 months of age, the rats in groups C and D had significantly higher test results than those in the control group. In the three-point flexion tests at 16 months of age, the results from groups A, B, and C were nearly the same as those from the control group. The results from group D, however, showed a significant increase. Examination of the microstructure of the femoral condyles at 16 months of age revealed controlled destruction of the trabecular structure in groups C and D. These findings suggest that supplementing the diet from infancy with Ca, vitamin K, and vitamin D might prevent bone fractures due to osteoporosis.