Computer-Based Radiographic Quantification of Joint Space Narrowing Progression Using Sequential Hand Radiographs: Validation Study in Rheumatoid Arthritis Patients from Multiple Institutions

We have developed a refined computer-based method to detect joint space narrowing (JSN) progression with the joint space narrowing progression index (JSNPI) by superimposing sequential hand radiographs. The purpose of this study is to assess the validity of a computer-based method using images obtained from multiple institutions in rheumatoid arthritis (RA) patients. Sequential hand radiographs of 42 patients (37 females and 5 males) with RA from two institutions were analyzed by a computer-based method and visual scoring systems as a standard of reference. The JSNPI above the smallest detectable difference (SDD) defined JSN progression on the joint level. The sensitivity and specificity of the computer-based method for JSN progression was calculated using the SDD and a receiver operating characteristic (ROC) curve. Out of 314 metacarpophalangeal joints, 34 joints progressed based on the SDD, while 11 joints widened. Twenty-one joints progressed in the computer-based method, 11 joints in the scoring systems, and 13 joints in both methods. Based on the SDD, we found lower sensitivity and higher specificity with 54.2 and 92.8%, respectively. At the most discriminant cutoff point according to the ROC curve, the sensitivity and specificity was 70.8 and 81.7%, respectively. The proposed computer-based method provides quantitative measurement of JSN progression using sequential hand radiographs and may be a useful tool in follow-up assessment of joint damage in RA patients.     

Functional differences between wild‐type and mutant‐type BRCA1‐associated protein 1 tumor suppressor against malignant mesothelioma cells

Malignant mesothelioma (MM) shows inactivation of the BRCA1‐associated protein 1 (BAP1) gene. In this study, we found BAP1 mutations in 5 (26%) of the 19 cell lines that we established from Japanese MM patients, and examined functional differences between the WT and mutant BAP1. First, we studied the subcellular localization of BAP1, demonstrating that the WT primarily resides in the nucleus and that the mutant BAP1 is found in the cytoplasm of the cells. Transduction of the WT BAP1 vector into MM cells with homozygous deletion at the BAP1 3′ side resulted in both inhibition of cell proliferation and anchorage‐independent cell growth, whereas BAP1 mutants of a missense or C‐terminal truncated form showed impaired growth inhibitory effects. Next, we studied how BAP1 is involved in MM cell survival after irradiation (IR), which causes DNA damage. After IR, we found that both WT and mutant BAP1 were similarly phosphorylated and phospho‐BAP1 localized mainly in the nucleus. Interestingly, BRCA1 proteins were decreased in the MM cells with BAP1 deletion, and transduction of the mutants as well as WT BAP1 increased BRCA1 proteins, suggesting that BAP1 may promote DNA repair partly through stabilizing BRCA1. Furthermore, using the MM cells with BAP1 deletion, we found that WT BAP1, and even a missense mutant, conferred a higher survival rate after IR compared to the control vector. Our results suggested that, whereas WT BAP1 suppresses MM cell proliferation and restores cell survival after IR damage, some mutant BAP1 may also moderately retain these functions.     

Efficacy of the polo-like kinase inhibitor rigosertib,alone or in combination with Abelson tyrosine kinase inhibitors,against break point cluster region-c-Abelson-positive leukemia cells

The potency of Abelson (ABL) tyrosine kinase inhibitors (TKIs) against chronic myeloid leukemia (CML) has been demonstrated. However, ABL TKI resistance can develop. In this study, we investigated the efficacy of a combination therapy including rigosertib (ON 01910.Na), a polo-like kinase (PLK) and phosphoinositide 3-kinase (PI3K) inhibitor, and ABL TKIs. A 72-h rigosertib treatment was found to inhibit cell growth, induce apoptosis, reduce phosphorylation of the breakpoint cluster region-c (BCR)-ABL and its substrate Crk-L, and increase the activities of caspase 3 and poly (ADP-ribose) polymerase (PARP). This combination therapy also exerted a synergistic inhibitory effect on Philadelphia chromosome (Ph)-positive cell proliferation and reduced the phosphorylation of BCR-ABL and Crk-L while increasing that of cleaved PARP and the H2A.X histone. Rigosertib also potently inhibited the growth of ABL TKI-resistant cells, and cotreatment with ABL TKIs and rigosertib induced higher cytotoxicity. These results indicate that rigosertib treatment may be a powerful strategy against ABL TKI-resistant cells and could enhance the cytotoxic effects of ABL TKIs.     

Impact of a high-fat diet on bone health during growth

Background

An inappropriate eating habit is a relatively easily modified risk factor for obesity and osteoporosis in adults. The consumption of high-fat foods is known to induce obesity. Although numerous studies have documented a relationship between high-fat diet (HFD)-induced obesity and osteoporosis, no consensus has been reached. In addition, few data on the relationships between mandibular properties and an HFD in the growth period are available.

Immunohistochemical detection of uPA,tPA, and PAI-1 in a stasis-induced deep vein thrombosis model and its application to thrombus age estimation

We immunohistochemically examined the expression of urokinase-type plasminogen activator (uPA), tissue-type plasminogen activator (tPA), and plasminogen-activator inhibitor type-1 (PAI-1) using venous thrombi developed by ligation of the inferior vena cava (IVC) in mice. The uPA-, tPA- and PAI-1-positive cells could be firstly detected 5, 7, and 3 days, respectively, after IVC ligation. Morphometrically, the number of PAI-1-positive cells was significantly higher than those of uPA- and tPA-positive cells at later than 7 days. In all of the thrombus samples aged 10–21 days, the uPA/PAI-1 and tPA/PAI-1 ratios were >0.1 and >0.2, respectively. In contrast, all of the thrombus samples aged 1–7 days had uPA/PAI-1 of <0.1 and tPA/PAI-1 ratios of <0.2. These findings implied that uPA/PAI-1 of >0.1 and tPA/PAI-1 of >0.2 indicated an age of 10 days or more. Moreover, in four of five samples aged 10 days, uPA/PAI-1 ratios were <0.3, and the remaining one had uPA/PAI-1 of 0.32. All thrombi aged 14–21 days showed values greater than 0.3. Thus, uPA/PAI-1 ratios, markedly exceeding 0.3, strongly indicated an age of more than 14 days. The present study demonstrated that the immunohistochemical detection of uPA, tPA, and PAI-1 was suitable to estimate the age of venous thrombi.     

Combination of Factor H Mutation and Properdin Deficiency Causes Severe C3 Glomerulonephritis

Factor H (fH) and properdin both modulate complement; however, fH inhibits activation, and properdin promotes activation of the alternative pathway of complement. Mutations in fH associate with several human kidney diseases, but whether inhibiting properdin would be beneficial in these diseases is unknown. Here, we found that either genetic or pharmacological blockade of properdin, which we expected to be therapeutic, converted the mild C3 GN of an fH-mutant mouse to a lethal C3 GN with features of human dense deposit disease. We attributed this phenotypic change to a differential effect of properdin on the dynamics of alternative pathway complement activation in the fluid phase and the cell surface in the fH-mutant mice. Thus, in fH mutation-related C3 glomerulopathy, additional factors that impact the activation of the alternative pathway of complement critically determine the nature and severity of kidney pathology. These results show that therapeutic manipulation of the complement system requires rigorous disease-specific target validation.Complement is a component of the innate immune system that plays a key role in recognizing and fighting pathogenic infections.^1,2 Three main pathways exist to initiate complement activation: the classic pathway, the lectin pathway, and the alternative pathway (AP). The classic and lectin pathways are initiated by antigen–antibody complexes and microbial sugar molecules, respectively. The AP is constitutively active at a low level caused by spontaneous C3 tick-over and capable of self-amplification on foreign surfaces that lack regulatory control.^1,2 Although complement plays a physiologic role in host defense and homeostasis, inappropriately activated complement can lead to serious tissue injury. In particular, AP dysregulation has been implicated in many complement-mediated human autoimmune disorders.^3–6AP complement activation is regulated by several membrane-bound and fluid-phase proteins. Among them, factor H (fH) is an abundant plasma regulator that works to restrict the activity of the C3 convertase C3bBb both on the cell surface and in the fluid phase.^7–9 It is a glycoprotein composed of 20 short consensus repeat (SCR) domains, and it inhibits the AP C3 convertase C3bBb by decay acceleration and cofactor activity for factor I (fI)-mediated proteolytic cleavage of C3b. The C-terminal SCR domains of fH interact with surface-deposited C3b and polyanionic molecules on eukaryotic cells, and they play a critical role in determining its affinity for host tissues.^10,11 The N-terminal 1–4 SCRs of fH are responsible for its complement-regulating activity. Opposing the activities of fH and other membrane complement regulators, factor properdin (fP) is a plasma protein that facilitates AP complement activation. It stabilizes the labile AP C3 convertase C3bBb, significantly extending its half-life.¹² Recent studies have shown that fP may also work as an initiator of AP complement on certain activating surfaces.^13–18 In contrast to the multitude of negative regulators, fP is the only known positive regulator of the complement cascade.Mutations in fH in animals and man are associated with several kidney pathologies, including C3 GN, dense deposit disease (DDD), and atypical hemolytic uremic syndrome (aHUS).^9,19–21 Development of these diseases has also been linked to other abnormalities in AP complement regulation, such as the presence of nephritic factors and mutations in C3, factor B (fB), membrane cofactor protein, and fI.^22–24 Many of these disease-causing defects, including fH mutations, lack complete penetrance, and presently it is not well understood how disease phenotypes associated with these defects might be affected by other modifier genes or abnormalities. Here, we provide a striking example in mice, where loss of fP activity, while expected to be therapeutic, surprisingly converted a mild C3 GN phenotype of an fH mutant mouse to lethal C3 GN resembling human DDD. Our results shed new light on the pathogenesis of fH-related kidney diseases and have therapeutic implications for human C3 glomerulopathy patients.