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Toshiyuki Ota

Publications and source records attributed to Toshiyuki Ota.

8 recordsLinked to original sources
PubMed2006

[Immunologic laboratory testing in clinical practice for rheumatoid arthritis].

The recent clinical practices for rheumatoid arthritis have changed greatly. First, biologic agents such as tumor necrosis factor blocker have been developed as well as disease-modifying antirheumatic drugs, with great efficacy in intractable RA. On the other hand, the importance of early effective therapeutic intervention has been recognized since early treatment prevents the progression of joint damage. However, early diagnosis of RA is not so easy because of the lack of appropriate diagnostic criteria. New laboratory tests have appeared for the diagnosis and prognostic prediction of RA. Among them, anticyclic citrullinated peptide antibodies (anti-CCP), which bind epitopes containing citrulline, seem to be attracting the most attention. Although rheumatoid factor (RF) is the only serologic marker among the seven classification criteria of the American College of Rheumatology (ACR) for RA, variability of the RF assay within laboratories and/or between laboratories, and quality assurance has not been established. We must address the standardization of RF assay as soon as possible.

Antirheumatic Agents↗
PubMed2004

The W258X mutation in SLC22A12 is the predominant cause of Japanese renal hypouricemia.

Recently, a urate transporter, hURAT1 (human uric acid transporter 1) encoded by SLC22A12, was isolated from the human kidney. hURAT1 is presumed to play the central role in reabsorption of urate from glomerular filtrate. In the present study, we analyzed SLC22A12 in seven unrelated Japanese patients with renal hypouricemia whose serum level of urate was less than 1.0 mg/dl, and their family members. We performed direct DNA sequencing of the exon and exon-intron boundaries of SLC22A12 using genomic DNA. Six of the seven patients (86%) possess mutations in SLC22A12. In five patients, a homozygous G to A transition at nucleotide 774 within exon 4 of SLC22A12, which forms a stop codon (TGA) at codon 258 (TGG), was identified (W258X). In one patient, the C to T transition within exon 3, which changes threonine at codon 217 to methionine (T217 M), and the W258X mutation were found (compound heterozygote). Thus, among 12 mutational alleles in six patients, 11 were the W258 X mutation (92%). Family members with the heterozygous W258X mutation (carriers) show relatively low levels of serum urate. The present study demonstrates that homozygous W258X mutation is the predominant genetic cause of idiopathic renal hypouricemia in Japanese patients.

Adolescent↗
PubMed2004

[Successful treatment of intravenous cyclophosphamide pulse therapy for lupus myelitis with urinary disturbance and acute confusional state].

A 18-year-old female had low grade fever, butterfly rush, proteinuria, leukocytopenia and hypocomplimentemia in 1988, and she was diagnosed as systemic lupus erythematosus (SLE) with lupus nephritis (WHOIIb). Treatments with prednisolone and mizoribine resulted in the remission for three years. In May 2001, she presented neurosis and polakisuria despite of the increase of prednisolone to 20 mg/day. Finally, she admitted in our hospital because of manic and repressive state and disorientaion. A brain MRI revealed high intensity lesions in bilateral basal ganglia in T2 weighted images, and cerebrospinal fluid showed elevated protein and IFN-alpha (421 IU/ml). In addition, she manifested neurogenic bladder, muscle weakness and hyperactive deep tendon reflex of bilateral lower limbs due to both supranuclear disorder and hypesthesia under the Th 10 level. Spinal MRI revealed marked atrophy and high intensity signals at the middle to lower thoracic spinal cord in T2 weighted images, indicating complication of lupus myelitis as well as cerebral involvement. Although the symptoms of CNS lupus did not respond to prednisolone, twelve monthly cyclophosphamide pulse therapy (IV-CY) has resolved urinary disturbance, muscle weakness and sensory loss, along with the improvement of both cerebral and spinal MRI images. Lupus myelitis and neurogenic bladder are the rare, but very refractory manifestation among CNS involvement of SLE. We here propose IV-CY as an invaluable choice for the treatment of not only active lupus myelitis but also neurogenic bladder resisted for steroid.

Adolescent↗
PubMed2003

Internalization of antibodies by endothelial cells via fibronectin implicating a novel mechanism in lupus nephritis.

BACKGROUND: One of the crucial events in lupus nephritis is the glomerular deposition of immunoglobulins (Igs), of which pathogenic properties have been proposed mostly to be either type IIor type III allergic reactions. Some of IgG3-producing hybridoma clones established from an MRL/MpTn-gld/gld (MRL/gld) lupus mouse generate wire loop-like lesions in glomeruli resembling lupus nephritis when injected into SCID mice. These clones are useful for analyzing the mechanisms of glomerular deposition of antibodies in lupus nephritis at the monoclonal level. METHODS: Glomerular lesions of SCID mice injected with the hybridoma clones, 17H8a or 1G3 as control were analyzed by light and electron microscopy. Interaction of the antibodies with human glomerular endothelial cells (HGECs) and human umbilical vein endothelial cells (HUVECs) in vitro was studied by fluorescence microscopy, electron microscopy, and flow cytometry. RESULTS: Both antibodies did not show any antigen specificity for mouse glomeruli. The glomerular lesions generated by 17H8a, but not by 1G3, contained electron-dense deposits not only in subendothelial regions but also in the cytoplasm of endothelial cells, suggesting internalization of the 17H8a antibodies by endothelial cells. In cell culture studies, internalization of only 17H8a antibodies by HGECs and HUVECs was observed, but the antibodies did not have antigen specificity for both types of endothelial cells. The internalization by HUVECs was mediated by actin polymerization, and it was inhibited by RGDS (Arg-Gly-Asp-Ser) tetrapeptide, antihuman fibronectin and antihuman integrin beta1 monoclonal antibodies. CONCLUSION: The interaction between particular antibodies and endothelial cell surface integrins via fibronectin may be involved in their subsequent internalization by endothelial cells leading to antibody deposition in glomeruli. This may be one of the mechanisms of glomerular injury in lupus nephritis.

Animals↗
PubMed2003

[Successful treatment of intravenous cyclophosphamide pulse therapy for systemic lupus erythematosus complicated with steroid-resistant hemolytic anemia].

(Case 1) A 13-years-old female had multiple arthralgia and butterfly rush, when she admitted in our hospital in May 2001. Nephropathy, hemolytic anemia (Hb 6.3 g/dl and direct Coombs 3+) and high titers of antinuclear antibodies and anti-ds-DNA antibody were disclosed and she was diagnosed as systemic lupus erythematosus (SLE). Although combination therapy of PSL 60 mg/day with a steroid pulse therapy, cyclosporine or an immunosorbent treatment, severe hemolytic anemia remained. However, monthly cyclophosphamide pulse therapy (IV-CY), which was started for the steroid-resistant hemolytic anemia, has gradually become effective and Hb improved up to 11.4 g/dl after 6 courses of IV-CY. (Case 2) A 53-years-old woman diagnosed as SLE in 1978 and she had PSL 5 mg for over 10 years. Severe anemia (Hb 5.9 g/dl) was disclosed with a slight fever in June 2001, and she admitted in our hospital for further examinations. Progressive hemolytic anemia was revealed with marked decrease of Hb (3.4 g/dl) and high titer of direct Coombs (3+). Neither PSL (50 mg/day) nor steroid pulse therapy were effective against hemolytic anemia. In contrast, 3 courses of monthly IV-CY (500 mg/day) resulted in the resolution of hemolysis. It is well known that the steroid-resistant hemolytic anemia is extremely hard to treat and leads to miserable prognosis, but we here propose IV-CY as an alternative and invaluable choice for the treatment of refractory hemolytic anemia complicated with SLE.

Adolescent↗
PubMed2003

[Present status and problems with rheumatoid factor as a laboratory test].

Rheumatoid factor(RF) has generally been defined as antibodies against mammalian IgG Fc. In a majority of patients with rheumatoid arthritis(RA), RF can be regarded as an autoantibody because it binds to their own IgG. RF in RA, however, can bind to various other IgG antigens such as IgG allotypic antigens(Gm), isoallotypic antigens, species-specific IgG antigens, cross-reactive antigens shared by other mammalian IgG and neoantigens created within IgG by immune-complex formation. This multi-specific characterization of RF has caused interlaboratory variation and it has been difficult to conduct external quality assessment(EQA) using various qualitative and/or quantitative RF kits. In the future, RF measurement should be assessed by each kit's EQA. It is significant to make a distinction between the pathological and non-pathological roles of RF owing to improvement of vagueness in clinical evaluation of RF measurement. Complement activation by RF, measurement of functional affinity(avidity) and quantitative determination of IgG and/or IgA RF have been investigated by us and other investigators for evaluation of RF's pathological role. Quantitative determination of RF's physiological, innate and non-pathological role is so important in health and disease that we have developed IgM-class antiglobulin against neoantigens appearing not in heat-aggregated human IgG but in human IgG bound to antigen.

Humans↗
PubMed2002

[A case of rheumatoid arthritis with secondary amyloidosis in urinary bladder].

We document a case of 61-year-old woman with a 24 year history of rheumatoid arthritis (RA), who developed severe polyarthralgia, dry cough, paresthesia in the legs, frequent micturition, and severe macrohematuria. We diagnosed as severe RA with extraarticular manifestations based on interstitial pneumonia, mononeuritis multiplex, subcutaneous nodules, and high titer of rheumatoid factor. Ultrasonography demonstrated an intravesical mass lesion. A histological examination of the urinary bladder by endoscopic biopsy revealed marked deposition of AA amyloid. The diagnosis of secondary amyloidosis and bacterial cystitis were made based on histological findings and urine culture. At first, we administered antibiotics by intravenous infusion, which resulted in cure of cystitis and partial improvement of macrohematuria. Then combination therapy of corticosteroids and cyclophosphamide successfully reduced the disease activity of RA. There have only been a few reports published so far on the vesical amyloidosis in patients with RA. However, 5 of 10 patients (50%) in vesical amyloidosis died because of continuous massive hematuria, which induced disseminated intravascular coagulation and multiple organ failure. In conclusion, secondary amyloidosis of the urinary bladder should be considered as a possible cause of hematuria in patients with long-term RA and as an important prognosis factor of RA.

Amyloidosis↗