Functional coordination of three mitotic motors in Drosophila embryos

It is well established that multiple microtubule-based motors contribute to the formation and function of the mitotic spindle, but how the activities of these motors interrelate remains unclear. Here we visualize spindle formation in living Drosophila embryos to show that spindle pole movements are directed by a temporally coordinated balance of forces generated by three mitotic motors, cytoplasmic dynein, KLP61F, and Ncd. Specifically, our findings suggest that dynein acts to move the poles apart throughout mitosis and that this activity is augmented by KLP61F after the fenestration of the nuclear envelope, a process analogous to nuclear envelope breakdown, which occurs at the onset of prometaphase. Conversely, we find that Ncd generates forces that pull the poles together between interphase and metaphase, antagonizing the activity of both dynein and KLP61F and serving as a brake for spindle assembly. During anaphase, however, Ncd appears to have no effect on spindle pole movements, suggesting that its activity is down-regulated at this time, allowing dynein and KLP61F to drive spindle elongation during anaphase B.

Model for anaphase B: role of three mitotic motors in a switch from poleward flux to spindle elongation

It has been proposed that the suppression of poleward flux within interpolar microtubule (ipMT) bundles of Drosophila embryonic spindles couples outward forces generated by a sliding filament mechanism to anaphase spindle elongation. Here, we (i) propose a molecular mechanism in which the bipolar kinesin KLP61F persistently slides dynamically unstable ipMTs outward, the MT depolymerase KLP10A acts at the poles to convert ipMT sliding to flux, and the chromokinesin KLP3A inhibits the depolymerase to suppress flux, thereby coupling ipMT sliding to spindle elongation; (ii) used KLP3A inhibitors to interfere with the coupling process, which revealed an inverse linear relation between the rates of flux and elongation, supporting the proposed mechanism and demonstrating that the suppression of flux controls both the rate and onset of spindle elongation; and (iii) developed a mathematical model using force balance and rate equations to describe how motors sliding the highly dynamic ipMTs apart can drive spindle elongation at a steady rate determined by the extent of suppression of flux.

Dirigent proteins and dirigent sites in lignifying tissues

Tissue-specific dirigent protein gene expression and associated dirigent (site) localization were examined in various organs of Forsythia intermedia using tissue printing, in situ mRNA hybridization and immunolabeling techniques, respectively. Dirigent protein gene expression was primarily noted in the undifferentiated cambial regions of stem sections, whereas dirigent protein sites were detected mainly in the vascular cambium and ray parenchyma cell initials. Immunolocalization also revealed cross-reactivity with particular regions of the lignified cell walls, these being coincident with the known sites of initiation of lignin deposition. These latter regions are considered to harbor contiguous arrays of dirigent (monomer binding) sites for initiation of lignin biopolymer assembly. Dirigent protein mRNA expression was also localized in the vascular regions of roots and petioles, whereas in leaves the dirigent sites were primarily associated with the palisade layers and the vascular bundle. That is, dirigent protein mediated lignan biosynthesis was initiated primarily in the cambium and ray cell initial regions of stems as well as in the leaf palisade layers, this being in accordance with the occurrence of the lignans for defense purposes. Within lignified secondary xylem cell walls, however, dirigent sites were primarily localized in the S(1) sublayer and compound middle lamella, these being coincident with previously established sites for initiation of macromolecular lignin biosynthesis. Once initiation occurs, lignification is proposed to continue through template polymerization.

Identification and characterization of novel antimicrobial decapeptides generated by combinatorial chemistry

Novel combinatorial libraries consisting of simplified amino acid sequences were designed to screen for peptides active against the Candida albicans membrane. A novel decapeptide, KKVVFKVKFK, that had a unique primary amino acid sequence was identified in this work. This peptide irreversibly inhibited the growth of C. albicans and showed a broad range of antibacterial activity but no hemolytic activity. Circular dichroism spectra revealed that the predominant secondary structure of this peptide strongly depended on the membrane-mimetic environments; the peptide preferred to form an amphipathic alpha-helical structure in the presence of 50% trifluoroethanol, while it preferred to adopt a distorted alpha-helical structure in the presence of sodium dodecyl sulfate micelles. Experiments in which dye was released from vesicles indicated that this novel antimicrobial peptide killed microorganisms through the action on the membrane as its primary target. Replacement of amino acids in this active decapeptide on the basis of information from the libraries could provide unique information about factors affecting its antimicrobial activity such as its secondary structure, net positive charge, and hydrophobicity.

Oil components modulate physical characteristics and function of the natural oil emulsions as drug or gene delivery system

Oil-in-water (o/w) type lipid emulsions were formulated by using 18 different natural oils and egg phosphatidylcholine (egg PC) to investigate how emulsion particle size and stability change with different oils. Cottonseed, linseed and evening primrose oils formed emulsions with very large and unstable particles. Squalene, light mineral oil and jojoba bean oil formed stable emulsions with small particles. The remaining natural oils formed moderately stable emulsions. Emulsions with smaller initial particle size were more stable than those with larger particles. The correlation between emulsion size made with different oils and two physical properties of the oils was also investigated. The o/w interfacial tension and particle size of the emulsion were inversely proportional. The effect of viscosity was less pronounced. To study how the oil component in the emulsion modulates the in vitro release characteristics of lipophilic drugs, three different emulsions loaded with two different drugs were prepared. Squalene, soybean oil and linseed oil emulsions represented the most, medium and the least stable systems, respectively. For the lipophilic drugs, release was the slowest from the most stable squalene emulsion, followed by soybean oil and then by linseed oil emulsions. Cationic emulsions were also prepared with the above three different oils as gene carriers. In vitro transfection activity was the highest for the most stable squalene emulsion followed by soybean oil and then by linseed oil emulsions. Even though the in vitro transfection activity of emulsions were lower than the liposome in the absence of serum, the activity of squalene emulsion, for instance, was ca. 30 times higher than that of liposome in the presence of 80% (v/v) serum. In conclusion, the choice of oil component in o/w emulsion is important in formulating emulsion-based drug or gene delivery systems.

Phase II study of ceralasertib (AZD6738) in combination with durvalumab in patients with advanced/metastatic melanoma who have failed prior anti-PD-1 therapy

BACKGROUND

Modulating the DNA damage response and repair (DDR) pathways is a promising strategy for boosting cancer immunotherapy. Ceralasertib (AZD6738) is an oral inhibitor of the serine/threonine protein kinase ataxia telangiectasia and Rad3-related protein, which is crucial for DDR.

PATIENTS AND METHODS

This phase II trial evaluated ceralasertib plus durvalumab for the treatment of patients with metastatic melanoma who had failed anti-programmed cell death protein 1 therapy.

RESULTS

Among the 30 patients, we observed an overall response rate of 31.0% and a disease control rate of 63.3%. Responses were evident across patients with acral, mucosal, and cutaneous melanoma. The median duration of response was 8.8 months (range, 3.8-11.7 months). The median progression-free survival was 7.1 months (95% confidence interval, 3.6-10.6 months), and the median overall survival was 14.2 months (95% confidence interval, 9.3-19.1 months). Common adverse events were largely hematologic and manageable with dose interruptions and reductions. Exploratory biomarker analysis suggested that tumors with an immune-enriched microenvironment or alterations in the DDR pathway were more likely to respond to the study treatment.

CONCLUSION

We conclude that ceralasertib in combination with durvalumab has promising antitumor activity among patients with metastatic melanoma who have failed anti-programmed cell death protein 1 therapy, and constitute a population with unmet needs.

A Prospective Study on the Value of Ultrasound Microflow Assessment to Distinguish Malignant from Benign Solid Breast Masses: Association between Ultrasound Parameters and Histologic Microvessel Densities

OBJECTIVE

To investigate the value of ultrasound (US) microflow assessment in distinguishing malignant from benign solid breast masses as well as the association between US parameters and histologic microvessel density (MVD).

MATERIALS AND METHODS

Ninety-eight breast masses (57 benign and 41 malignant) were examined using Superb Microvascular Imaging (SMI) and contrast-enhanced US (CEUS) before biopsy. Two radiologists evaluated the quantitative and qualitative vascular parameters on SMI (vascular index, morphology, distribution, and penetration) and CEUS (time-intensity curve analysis and enhancement characteristics). US parameters were compared between benign and malignant masses and the diagnostic performance was compared between SMI and CEUS. Subgroup analysis was performed according to lesion size. The effect of vascular parameters on downgrading Breast Imaging Reporting and Data System (BI-RADS) category 4A masses was evaluated. The association between histologic MVD and US parameters was analyzed.

RESULTS

Malignant masses were associated with a higher vascular index (15.1 ± 7.3 vs. 5.9 ± 5.6), complex vessel morphology (82.9% vs. 42.1%), central vascularity (95.1% vs. 59.6%), penetrating vessels (80.5% vs. 31.6%) on SMI (all, p < 0.001), as well as higher peak intensity (37.1 ± 25.7 vs. 17.0 ± 15.8, p < 0.001), slope (10.6 ± 11.2 vs. 3.9 ± 4.2, p = 0.001), area (1035.7 ± 726.9 vs. 458.2 ± 410.2, p < 0.001), hyperenhancement (95.1% vs. 70.2%, p = 0.005), centripetal enhancement (70.7% vs. 45.6%, p = 0.023), penetrating vessels (65.9% vs. 22.8%, p < 0.001), and perfusion defects (31.7% vs. 3.5%, p < 0.001) on CEUS (p ≤ 0.023). The areas under the receiver operating characteristic curve (AUCs) of SMI and CEUS were 0.853 and 0.841, respectively (p = 0.803). In 19 masses measuring < 10 mm, central vascularity on SMI was associated with malignancy (100% vs. 38.5%, p = 0.018). Considering all benign SMI parameters on the BI-RADS assessment, unnecessary biopsies could be avoided in 12 category 4A masses with improved AUCs (0.500 vs. 0.605, p < 0.001). US vascular parameters associated with malignancy showed higher MVD (p ≤ 0.016). MVD was higher in malignant masses than in benign masses, and malignant masses negative for estrogen receptor or positive for Ki67 had higher MVD (p < 0.05).

CONCLUSION

US microflow assessment using SMI and CEUS is valuable in distinguishing malignant from benign solid breast masses, and US vascular parameters are associated with histologic MVD.

Role of annexin II tetramer in plasminogen activation

The enzymatic cascade triggered by activation of plasminogen has been implicated in a variety of normal and pathologic events, such as fibrinolysis, wound healing, tissue remodeling, embryogenesis, and the invasion and spread of transformed tumor cells. Recent data established that the Ca(2+)- and phospholipid-binding protein, annexin II heterotetramer (AIIt) binds tissue-type plasminogen activator (tPA), plasminogen, and plasmin, and dramatically stimulates the tPA-dependent conversion of plasminogen to plasmin in vitro. Interestingly, the binding of plasmin to AIIt can inhibit the activity of the enzyme, suggesting that plasmin bound to the cell surface is regulated by AIIt. The existing experimental evidence suggests that AIIt is the key physiological receptor for plasminogen on the extracellular surface of endothelial cells.

Identification and characterization of the antimicrobial peptide corresponding to C-terminal beta-sheet domain of tenecin 1, an antibacterial protein of larvae of Tenebrio molitor

An active fragment was identified from tenecin 1, an antibacterial protein belonging to the insect defensin family, by synthesizing the peptides corresponding to the three regions of tenecin 1. Only the fragment corresponding to the C-terminal beta-sheet domain showed activity against fungi as well as Gram-positive and Gram-negative bacteria, whereas tenecin 1, the native protein, showed activity only against Gram-positive bacteria. CD spectra indicated that each fragment in a membrane-mimetic environment might adopt a secondary structure corresponding to its region in the protein. The leakage of dye from liposomes induced by this fragment suggested that this fragment acts on the membrane of pathogens as a primary mode of action. A comparison between the structure and the activity of each fragment indicated that a net positive charge was a prerequisite factor for activity. To the best of our knowledge this is the first report in which the fragment corresponding to the beta-sheet region in antibacterial proteins, which consists of alpha-helical and beta-sheet regions, has been identified as a primary active fragment.

Postoperative hypoalbuminemia as a risk factor for surgical site infection after oral cancer surgery

OBJECTIVES

Postoperative surgical site infection (SSI) is a frequent postoperative complication in patients with oral cancer and significantly affects patient recovery and medical expenses. The aim of this study was to examine the predictors of SSI in patients undergoing major surgery for oral or oropharyngeal squamous cell carcinoma (OSCC) and to determine the relationship between perioperative albumin and the development of SSI.

SUBJECTS AND METHODS

In 337 consecutive patients who underwent clean-contaminated surgery for OSCC, serum albumin, glucose, and hemoglobin levels were perioperatively measured. Differences between the groups were examined using Fisher's exact test, Mann-Whitney U-test, and multiple logistic regression analysis.

RESULTS

Surgical site infection was detected in 88 (26.1%) patients with median time to development of 10 (2-25) days. Multiple logistic regression analysis showed that only postoperative serum albumin < 2.5 g dl(-1) was an independent variable predictive of SSI (P = 0.003). The duration of hospital stay was negatively correlated with postoperative albumin (R(2) = -0.302, P < 0.001).

CONCLUSION

Early postoperative hypoalbuminemia <2.5 g dl(-1) is an independent risk factor for the development of SSI in patients undergoing oral cancer surgery. Clinicians should be aware of the implications of postoperative hypoalbuminemia and consider more intensive postoperative care in these patients.

Rydberg-Mediated Entanglement in a Two-Dimensional Neutral Atom Qubit Array

We demonstrate high fidelity two-qubit Rydberg blockade and entanglement on a pair of sites in a large two-dimensional qubit array. The qubit array is defined by a grid of blue detuned lines of light with 121 sites for trapping atomic qubits. Improved experimental methods have increased the observed Bell state fidelity to F_{Bell}=0.86(2). Accounting for errors in state preparation and measurement we infer a fidelity of F_{Bell}^{-SPAM}=0.88. Accounting for errors in single qubit operations we infer that a Bell state created with the Rydberg mediated C_{Z} gate has a fidelity of F_{Bell}^{C_{Z}}=0.89. Comparison with a detailed error model based on quantum process matrices indicates that finite atom temperature and laser noise are the dominant error sources contributing to the observed gate infidelity.

Primary amino acid sequence and structure of human pyruvate carboxylase

Pyruvate carboxylase (PC) (pyruvate:carbon dioxide ligase (ADP-forming), EC 6.4.1.1.), a nuclear-encoded mitochondrial enzyme, catalyzes the conversion of pyruvate to oxaloacetate. We have isolated and characterized cDNAs spanning the entire coding region of human PC. The sequence of human PC has an open reading frame of 3537 nucleotides which encodes for a polypeptide with a length of 1178 amino acids. The identity of the cDNA as PC is confirmed by comparison to PC cDNAs of other species and sequenced peptide fragments of mammalian PC. The M(r) of the full length precursor protein is 129,576 and that of the mature apoprotein is 127,370. RNA blot analysis from a variety of human tissues demonstrates that the highest level of PC mRNA is found in liver corresponding to this tissue's high level of PC activity. Based on homology with other biotin-containing proteins, the ATP, pyruvate, and biotin-binding sites can be identified. One of two patients with documented PC deficiency was found to be missing PC mRNA, further confirming the identity of this cDNA.

Noncancer health events as a leading cause of competing mortality in advanced head and neck cancer

BACKGROUND

The survival of patients with head and neck squamous cell carcinoma (HNSCC) can be affected by noncancer health events (NCHE) as well as by index cancer progression and second primary cancer (SPC). This study aimed to investigate the risk factors for NCHE and noncancer mortality (NCM) in patients with advanced-stage HNSCC.

PATIENTS AND METHODS

This cohort study involved 600 consecutive patients with overall stage III to IV HNSCC who were treated between 2001 and 2010 at our tertiary referral hospital. NCHE was defined as re-admission (i.e. after the primary treatments for the index tumors) due to noncancer-related causes. The incidences of NCHE and NCM and their risk factors were analyzed by using cumulative incidence and cause-specific hazard functions.

RESULTS

During a median follow-up period of 54 months, 224 (37.3%) and 55 (9.2%) of the 600 patients had NCHE and NCM, respectively. The 5-year index cancer mortality, SPC mortality, and NCM rates were 23.8%, 4.2%, and 8.9%, respectively. Multivariate analyses revealed that body mass index <20 kg/m(2) (P = 0.018), Charlson comorbidity index (CCI) ≥1 (P < 0.001), tumor recurrence (P < 0.001), SPC occurrence (P < 0.001), and initial chemotherapy (P = 0.049) were independent NCHE predictors. Older age (P < 0.001), CCI ≥1 (P = 0.008), tumor recurrence (P < 0.001), and SPC occurrence (P = 0.047) were independent NCM predictors. Patients with respiratory NCHE were at a higher risk of NCM than patients with other NCHE types (P < 0.001).

CONCLUSIONS

One or more comorbidities, tumor recurrence, and SPC occurrence were independent predictors of both NCHE and NCM. Patients with respiratory NCHE had a particularly high risk of NCM.

Purification and characterization of A61. An angiostatin-like plasminogen fragment produced by plasmin autodigestion in the absence of sulfhydryl donors

Plasmin, a broad spectrum proteinase, is inactivated by an autoproteolytic reaction that results in the destruction of the heavy and light chains of the protein. Recently we demonstrated that a 61-kDa plasmin fragment was one of the major products of this autoproteolytic reaction (Fitzpatrick, S. L., Kassam, G., Choi, K. S., Kang, H. M., Fogg, D. K., and Waisman, D. M. (2000)Biochemistry 39, 1021-1028). In the present communication we have identified the 61-kDa plasmin fragment as a novel four kringle-containing protein consisting of the amino acid sequence Lys(78)-Lys(468). To avoid confusion with the plasmin(ogen) fragment, angiostatin(R) (Lys(78)-Ala(440)), we have named this protein A(61). Unlike angiostatin, A(61) was produced in vitro from plasmin autodigestion in the absence of sulfhydryl donors. A(61) bound to lysine-Sepharose and also underwent a large increase in fluorescence yield upon binding of the lysine analogue, trans-4-aminomethylcyclohexanecarboxylic acid. Circular dichroism suggested that A(61) was composed of 21% beta-strand, 14% beta-turn, 18% 3(1)-helix and 8% 3(10)-helix. A(61) was an anti-angiogenic protein as indicated by the inhibition of bovine capillary endothelial cell proliferation. Plasminogen was converted to A(61) by HT1080 cells and bovine capillary endothelial cells. Furthermore, a plasminogen fragment similar to A(61) was present in the serum of humans as well as normal and tumor-bearing mice. These results establish that plasmin turnover can generate anti-angiogenic plasmin fragments in a nonpathological setting.

Tumor stiffness measured by shear wave elastography correlates with tumor hypoxia as well as histologic biomarkers in breast cancer

Background

Shear wave elastography (SWE) is an ultrasound technique for the noninvasive quantification of tissue stiffness. The hypoxic tumor microenvironment promotes tumor stiffness and is associated with poor prognosis in cancer. We aimed to investigate the correlation between tumor hypoxia and histologic biomarkers and tumor stiffness measured by SWE in breast cancer.

Methods

From June 2016 to January 2018, 82 women with invasive breast cancer who underwent SWE before treatment were enrolled. Average tumor elasticity (E_average) and tumor-to-fat elasticity ratio (E_ratio) were extracted from SWE. Immunohistochemical staining of glucose transporter 1 (GLUT1) was used to assess tumor hypoxia in breast cancer tissues and automated digital image analysis was performed to assess GLUT1 activities. Spearman correlation and logistic regression analyses were performed to identify associations between GLUT1 expression and SWE values, histologic biomarkers, and molecular subtypes. The Mann–Whitney U test, t test, or Kruskal–Wallis test was used to compare SWE values and histologic features according to the GLUT1 expression (≤the median vs > median).

Results

E_average (r = 0.676) and E_ratio (r = 0.411) correlated significantly with GLUT1 expression (both p <  0.001). E_average was significantly higher in cancers with estrogen receptor (ER)–, progesterone receptor (PR)–, Ki67+, and high-grade (p <  0.05). E_ratio was higher in cancers with Ki67+, lymph node metastasis, and high-grade (p <  0.05). Cancers with high GLUT1 expression (>median) had higher E_average (mean, 85.4 kPa vs 125.5 kPa) and E_ratio (mean, 11.7 vs 17.9), and more frequent ER– (21.7% vs 78.3%), PR– (26.4% vs 73.1%), Ki67+ (31.7%% vs 68.3%), human epidermal growth factor receptor 2 (HER2) + (25.0% vs 75.0%), high-grade (28.6% vs 71.4%), and HER2-overexpressing (25.0% vs 75.0%) and triple-negative (23.1% vs 76.9%) subtypes (p <  0.05). Multivariable analysis showed that E_average was independently associated with GLUT1 expression (p <  0.001).

Conclusions

Tumor stiffness on SWE is significantly correlated with tumor hypoxia as well as histologic biomarkers. In particular, E_average on SWE has independent prognostic significance for tumor hypoxia in the multivariable analysis and can potentially be used as a noninvasive imaging biomarker to predict prognosis and pretreatment risk stratification in breast cancer patients.

Identification of a common mutation (Gly194Cys) in both Arab Moslem and Ashkenazi Jewish patients with dihydrolipoamide dehydrogenase (E3) deficiency: possible beneficial effect of vitamin therapy

Dihydrolipoamide dehydrogenase (E3) deficiency with a clinical phenotype and genotype (Gly194Cys homozygous) previously identified only in Ashkenazi Jewish patients, was diagnosed in two Palestinian Arab siblings and two unrelated Ashkenazi Jewish patients. While three of the four patients died in childhood without specific treatment, the surviving patient at age 18 years may have benefited from long-term daily supplementation with a cocktail of riboflavin, biotin, coenzyme Q and carnitine.

Kidney fibrosis is independent of the amount of ascorbic acid in mice with unilateral ureteral obstruction

In response to sustained damage to a kidney, fibrosis that can be characterized as the deposition of a collagenous matrix occurs and consequently causes chronic kidney failure. Because most animals used in experiments synthesize ascorbic acid (AsA) from glucose, the roles of AsA in fibrotic kidney diseases are largely unknown. Unilateral ureteric obstruction (UUO) mimics the complex pathophysiology of chronic obstructive nephropathy and is an ideal model for the investigation of the roles of AsA in kidney failure. We examined the impact of a deficiency of Akr1a, a gene that encodes aldehyde reductase and is responsible for the production of AsA, on fibrotic damage caused by UUO in mice. Oxidatively modified DNA was elevated in wild-type and Akr1a-deficient kidneys as a result of UUO to a similar extent, and was only slightly suppressed by the administration of AsA. Even though Akrla-deficient mice could produce only about 10% of the AsA produced by wild-type mice, no difference was observed in collagen I synthesis under pathological conditions. The data implied either a low demand for AsA or the presence of another electron donor for collagen I production in the mouse kidney. Next, we attempted to elucidate the potential causes for oxidative damage in kidney cells during the fibrotic change. We found decreases in mitochondrial proteins, particularly in electron transport complexes, at the initial stage of the kidney fibrosis. The data imply that a dysfunction of the mitochondria leads to an elevation of ROS, which results in kidney fibrosis by stimulating cellular transformation to myofibroblasts.

Randomized clinical trial of duct-to-mucosa pancreaticogastrostomy versus handsewn closure after distal pancreatectomy

BACKGROUND

Postoperative pancreatic fistula (POPF) remains a major cause of morbidity after distal pancreatectomy. The aim of this study was to investigate whether duct-to-mucosa pancreaticogastrostomy of the pancreatic stump decreased clinical POPF formation compared with handsewn closure after distal pancreatectomy.

METHODS

This multicentre RCT was performed between April 2012 and June 2014. Patients undergoing distal pancreatectomy were assigned randomly to either duct-to-mucosa pancreaticogastrostomy or handsewn closure. The primary endpoint was the incidence of clinical POPF. Secondary endpoints were rates of other complications and length of hospital stay.

RESULTS

Some 80 patients were randomized, and 73 patients were evaluated in an intention-to-treat analysis: 36 in the pancreaticogastrostomy group and 37 in the handsewn closure group. The duration of operation was significantly longer in the pancreaticogastrostomy group than in the handsewn closure group (mean 268 versus 197 min respectively; P < 0·001). The incidence of clinical POPF did not differ between groups (7 of 36 versus 7 of 37; odds ratio (OR) 1·03, 95 per cent c.i. 0·32 to 3·10; P = 1·000). The rate of intra-abdominal fluid collection was significantly lower in the pancreaticogastrostomy group (6 of 36 versus 21 of 37; OR 0·15, 0·05 to 0·45; P < 0·001). There were no statistically significant differences in the rates of other complications or length of hospital stay.

CONCLUSION

Duct-to-mucosa pancreaticogastrostomy did not reduce the incidence of clinical POPF compared with handsewn closure of the pancreatic stump after distal pancreatectomy. Registration number UMIN000007426 (http://www.umin.ac.jp).