Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Takayuki Kon is active.

Publication


Featured researches published by Takayuki Kon.


The Journal of Rheumatology | 2012

Autofeedback from ultrasound images provides rapid improvement in palpation skills for identifying joint swelling in rheumatoid arthritis.

Michihiro Ogasawara; Go Murayama; Yusuke Yamada; Takuya Nemoto; Michiaki Kageyama; Shoko Toyama; Makio Kusaoi; Shin Onuma; Takayuki Kon; Fumio Sekiya; Kaoru Sugimoto; Ran Matsudaira; Masakazu Matsushita; Kurisu Tada; Kazuo Kempe; Ken Yamaji; Naoto Tamura; Yoshinari Takasaki

Objective. Joint swelling, an important factor in the classification criteria and disease activity assessment in rheumatoid arthritis (RA), renders joint palpation a necessary skill for physicians. Ultrasound (US) examination that visualizes soft tissue abnormalities is now used to assess musculoskeletal disease. We assessed the usefulness of US assessments in enhancing physical joint examination skills. Methods. We examined 1944 joints (bilateral shoulder, elbow, wrist, metacarpophalangeal joints 1–5, and knee joints) in 108 patients with RA during April–July 2011. We first physically examined and confirmed joint swelling; subsequently, the same rheumatologist conducted US examinations and multiple assessors graded the joint swelling. When the 2 results differed, we received autofeedback from the US results to improve the physical examination skills. Results. The sensitivities and specificities of physical examination for US-detected swollen joint, the correlation coefficient (CC) of the swollen joint counts, and the concordance rate in each patient for joint swelling sites and power Doppler (PD)-positive sites with the κ coefficients between the physical and US examinations were compared over time. We found that the sensitivity of physical examination increased by 42 percentage points (pp), while the specificity decreased by 18 pp. The average CC in June–July was greater than that in April–May. The percentage of κ coefficients > 0.8 increased from 8.8% to 17% for joint swelling and from 8.3% to 14% for PD-positive sites. Conclusion. Our results suggest that autofeedback from US assessment provides quick improvement in palpation skills for identifying joint swelling in patients with RA.


Modern Rheumatology | 2016

Predictive grade of ultrasound synovitis for diagnosing rheumatoid arthritis in clinical practice and the possible difference between patients with and without seropositivity

Kentaro Minowa; Michihiro Ogasawara; Go Murayama; Misa Gorai; Yusuke Yamada; Takuya Nemoto; Yuko Matsuki; Nagachika Sugisaki; Seiichiro Ando; Takayuki Kon; Kurisu Tada; Masakazu Matsushita; Ken Yamaji; Naoto Tamura; Yoshinari Takasaki

Objective. To determine the degree of contribution and the contributing factors of ultrasound in the diagnosis of rheumatoid arthritis (RA) in daily clinical practice and the predictive differences depending on seropositivity. Methods. We included 122 patients who presented with the main complaint of finger and/or wrist joint pain but for whom no definite diagnosis was reached or treatment strategy was provided. Ultrasound was performed on at least 22 joints (both wrist joints, proximal interphalangeal joint, and metacarpophalangeal joints), and patients were followed for ≥6 months. Factors contributing to RA diagnosis were determined and compared between seropositive and seronegative RA patients. Results. RA was diagnosed in 52 of 122 patients, in whom the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria (odds ratio [OR] = 4.74, P = 0.01) and gray scale (GS) grade of 3 (OR = 3.64, P = 0.04) for ≥ 1 joint were the contributing factors. In seropositive RA, the ACR/EULAR criteria (OR = 15.53, P < 0.001) and power Doppler (PD) ≥ 2 for ≥ 1 joint (OR = 10.48, P = 0.0048) were the contributing factors. In seronegative RA, PD ≥ 1 for ≥ 1 joint contributed the most (OR = 20.00, P = 0.0044), but the ACR/EULAR criteria did not contribute to RA diagnosis (P = 0.57). Conclusion. Ultrasound findings contributed to RA diagnosis in clinical practice. The contributing factors are different in the presence or absence of seropositivity, and ultrasound complementation was particularly useful in seronegative RA patients.


Modern Rheumatology | 2008

Cavitary lung lesion in a patient with systemic lupus erythematosus: an unusual manifestation of cytomegalovirus pneumonitis

Akira Katagiri; Toshitaka Ando; Takayuki Kon; Masato Yamada; Noboru Iida; Yoshinari Takasaki

We report a 35-year-old female patient with systemic lupus erythematosus (SLE). She was admitted due to deterioration of lupus nephritis and received treatment with a high dose of steroid and cyclosporine. Approximately 1 month after admission, the patient was also treated for cytomegalovirus (CMV) infection because she was found to have CMV antigenemia. Although a cavitary lesion was shown by chest computed tomography (CT), its cause could not be clarified by blood examination, smears or cultures, or by bronchoscopy. We considered that this lesion may have been caused by CMV pneumonitis because it was resolved during the treatment for CMV infection. It is known that CMV causes opportunistic infections in patients with collagen vascular diseases (CVD) who are receiving immunosuppressive therapy. However, it is extremely rare for a cavitary lesion to be formed as a result of CMV pneumonitis. Here we describe the details of this interesting case.


Modern Rheumatology | 2010

Investigation of pathological and clinical features of lupus nephritis in 73 autopsied cases with systemic lupus erythematosus

Takayuki Kon; Ken Yamaji; Kaoru Sugimoto; Michihiro Ogasawara; Kazuo Kenpe; Hitoshi Ogasawara; Kwangseok Yang; Hiroshi Tsuda; Toshiharu Matsumoto; Hiroshi Hashimoto; Yoshinari Takasaki

The aims of this study were to analyze the clinical and pathological features of lupus nephritis (LN) and examine the association between these features and pathological condition, treatment, and prognosis. Of the 177 systemic lupus erythematosus patients who died while receiving inpatient care at Juntendo University Hospital between 1960 and 2001, we investigated the clinical features, treatment, and pathological features of 73 of these who underwent pathological autopsy and had a clear medical history. We divided these cases into two groups, i.e., those up to 1979 (Group A) and those during and after 1980 (Group B) in order to investigate changes in tendencies by age. We also divided the cases into three groups by time interval between diagnosis and death to investigate long-term prognosis. Uremia was the direct cause of death in 38.9% of cases in Group A and only 10.8% of cases in Group B. Pathological features showed a tendency to change to a sclerotic lesion as the duration of the disorder became longer. Uremia attributable to LN was the direct cause of death in relatively fewer cases, although it is still found in the majority of LN cases and remains a problem requiring stringent management. The treatment of sclerotic lesions may be an issue that needs further attention.


Modern Rheumatology | 2014

Weighting with the Lansbury articular index improves the correlation of ultrasound score with serum matrix metalloproteinase-3 level in rheumatoid arthritis patients

Misa Gorai; Michihiro Ogasawara; Yuko Matsuki; Yusuke Yamada; Go Murayama; Nagachika Sugisaki; Takuya Nemoto; Seiichiro Ando; Kentaro Minowa; Takayuki Kon; Kurisu Tada; Masakazu Matsushita; Ken Yamaji; Naoto Tamura; Yoshinari Takasaki

Abstract Objective. To determine whether weighting improves the correlation of ultrasound (US) score with serum matrix metalloproteinase-3 (MMP-3) level in rheumatoid arthritis (RA). Methods. As ultrasound examination was performed on 100 RA patients, and the severity of synovial effusion and synovial hypertrophy and the blood flow were semi-quantitatively graded from 0 to 3 by using the gray-scale (GS) and power Doppler (PD) modes. We then calculated the sums of the scores of the 28 joints of each patient in the 2 modes, that is, the GS28 and PD28 scores, as well as the respective scores weighted using the Lansbury articular index (LAI, shoulder and elbow, × 12; wrist, × 8; and knee, × 24)—Lans GS28 and Lans PD28 scores. Result. The Lans PD28 score showed a higher correlation with MMP-3 (r = 0.591; 95% confidence interval, 0.446–0.705, p < 0.0001) than the existing measures. The scores of the large joints—the knee, shoulder, and elbow—correlated well with the serum MMP-3 level. Conclusion. Weighting with the LAI can improve the correlation of US findings with serum MMP-3 level. Bidirectional approach based on both serum MMP-3 level and US scores can further improve the assessment of disease activity in RA patients.


Modern Rheumatology | 2017

Predictive factors for mortality in elderly Japanese patients with severe microscopic polyangiitis: A retrospective single-center study

Yoshiyuki Abe; Naoto Tamura; Kwangseok Yang; Joe Matsuoka; Takayuki Kon; Ken Yamaji; Hiroshi Hashimoto; Hiroshi Tsuda; Yoshinari Takasaki

Abstract Purpose: To determine mortality and its predictive factors in elderly Japanese patients with severe microscopic polyangiitis (MPA). Method: This retrospective single-center study determined the mortality of 52 patients with MPA who were admitted to our geriatric medical center from 2002 to 2014. The variables at baseline, including patient demographics, clinical characteristics, and treatment, were analyzed for their association with mortality. Result: Mean age at onset of MPA was 73.2 years, and the one-year survival rate was 65.9%. Relapse was observed in 32.7%. Among variables at diagnosis, age, cardiomyopathy, central nervous system (CNS) involvement, alveolar hemorrhage, disease severity, the 1996 Five-Factor Score (FFS), and the 2009 FFS were associated with mortality in univariate analysis. Cardiomyopathy, CNS involvement, age >65 years, disease severity, Birmingham Vasculitis Activity Score, the 1996 FFS, and the 2009 FFS were associated with relapse-free survival in univariate analysis. Conclusion: We investigated mortality and relapse-free survival and their predictive factors in elderly Japanese patients with severe MPA. Age, disease severity, the 1996 FFS, and the 2009 FFS at diagnosis were prognostic factors for both mortality and relapse-free survival.


Therapeutic Apheresis and Dialysis | 2011

Effect of various anticoagulant agents on large-volume leukocytapheresis using new Cellsorba CS-180S Filter.

Katsura Hohtatsu; Ken Yamaji; Risa Yamada; Keisuke Oda; Michiaki Kageyama; Makio Kusaoi; Shin Onuma; Toshio Kawamoto; Kaoru Sugimoto; Fumio Sekiya; Takayuki Kon; Michihiro Ogasawara; Kazuo Kempe; Hiroshi Tsuda; Yoshinari Takasaki

We conducted a study to evaluate the effect of various anticoagulant agents on large‐volume leukocytapheresis using the new Cellsorba CS‐180S Filter filled with a changed solution of sodium pyrosulfite and sodium carbonate. We conducted the study on a total of 12 cases of rheumatoid arthritis. As the anticoagulant agents we used sodium citrate, nafamostat mesilate and low molecular weight heparin. The new Cellsorba CS‐180S was safely used with the various blood anticoagulant agents. Also, through adjustment of the sodium citrate percentage to the blood flow volume, it is hypothesized that it is possible to increase the neutrophil removal rate.


Therapeutic Apheresis and Dialysis | 2016

Separation of Circulating MicroRNAs Using Apheresis in Patients With Systemic Lupus Erythematosus.

Makio Kusaoi; Ken Yamaji; Yusuke Ishibe; Go Murayama; Takuya Nemoto; Fumio Sekiya; Takayuki Kon; Michihiro Ogasawara; Kazuo Kempe; Naoto Tamura; Yoshinari Takasaki

MicroRNAs (miRNAs), which are important inhibitors of mRNA translation, participate in differentiation, migration, cell proliferation, and cell death. The pathology of miRNAs results in alterations in protein expression. Recently, miRNAs circulating in peripheral blood have been shown to control the synthesis and translation of proteins at distal sites after intake into local cells. A number of studies are currently being conducted to investigate how to use miRNAs in disease treatment, but no studies have attempted to alleviate disease by directly eliminating miRNAs from blood. Therefore, we examined whether the removal or reduction of circulating miRNAs with apheresis improved pathologies caused by miRNAs.


The Journal of Rheumatology | 2015

Second-to-fourth Digit Ratio in Systemic Lupus Erythematosus

Kentaro Doe; Kazuhisa Nozawa; Takuya Hirai; Hiroshi Tsushima; Eri Hayashi; Kaori Hiruma; Seiichiro Ando; Soichiro Nakano; Takayuki Kon; Hirofumi Amano; Ken Yamaji; Naoto Tamura; Yoshinari Takasaki

Objective. Systemic lupus erythematosus (SLE) occurs predominantly in women, and sex hormones play an important role in SLE. Variation in the second-to-fourth digit ratio (2D4D ratio) is attributed to sex hormone exposure. Therefore, we evaluated the relationship between sex hormones and SLE by measuring 2D4D ratios. Methods. We measured 2D4D ratios in 100 patients with SLE and 200 normal healthy controls (NHC). Results. Patients with SLE had a lower 2D4D ratio than NHC. Conclusion. Our study suggests that patients with SLE have experienced high prenatal testosterone and low prenatal estrogen. To our knowledge, this is the first study evaluating the association between 2D4D ratio and SLE.


Journal of Clinical Apheresis | 2014

Reduction in bradykinin generation during leukocytapheresis using novel cellsorbaTM CS‐180S: Effects of changing the filling solution

Risa Yamada; Makio Kusaoi; Go Murayama; Misa Yasui; Ruka Hishinuma; Takuya Nemoto; Katsura Hohtatsu; Michiaki Kageyama; Toshio Kawamoto; Kaoru Sugimoto; Fumio Sekiya; Takayuki Kon; Michihiro Ogasawara; Kazuo Kempe; Ken Yamaji; Hiroshi Tsuda; Yoshinari Takasaki

We evaluated the bradykinin generation level during leukocytapheresis (LCAP) using novel CellsorbaTM CS‐180S, which has sodium pyrosulfite and sodium carbonate as a filling solution. Subjects of this study were 14 rheumatoid arthritis patients. Regardless of the type of anticoagulant used, bradykinin levels were lower with the novel CS‐180S than with the conventional CS‐180S (28.7 ± 53.3 vs. 8.0 ± 2.7 as the mean ± standard deviation). When anticoagulants other than nafamostat mesilate were used with the conventional CS‐180S, bradykinin levels increased at the column outlet compared with the column inlet, and adverse effects of bradykinin were seen in several cases. In contrast, bradykinin levels remained low and no bradykinin‐associated adverse events were observed with the novel CS‐180S. We recommend using the novel column instead of the conventional column in the treatment of LCAP. J. Clin. Apheresis 29:90–96, 2014.

Collaboration


Dive into the Takayuki Kon's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge