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Kaori Ikeda

Publications and source records attributed to Kaori Ikeda.

8 recordsLinked to original sources
PubMed2006

Amelioration of bone loss in collagen-induced arthritis by neutralizing anti-RANKL monoclonal antibody.

Receptor activator of NF-kappaB (RANK) and its ligand (RANKL) are pivotal regulators of osteoclast differentiation. RANK and RANKL also mediate T cell/dendritic cell (DC) interaction. Previous study has shown that RANK/RANKL interaction induces prolonged DC survival and antigen presentation. In the present study, we have newly established a hybridoma which produces neutralizing anti-RANKL monoclonal antibody (IK22-5). By treating collagen-induced arthritis (CIA) mice with IK22-5, we have investigated the role of RANKL in the pathogenesis of CIA. Although IK22-5 had no effect on immune responses or inflammation, it ameliorated bone loss at the site of inflammation. Histological analyses revealed that osteoclast formation was impaired at the site of joint inflammation in IK22-5-treated CIA mice. These results suggest the utility of anti-RANKL mAb for the prevention of osteoporosis associated with joint inflammation in RA.

Animals↗
PubMed2006

Autapses.

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Animals↗
PubMed2006

Evaluation of a 1 step TRAb assay for the detection of high-affinity components to hTSHR: evidences indicating superiority of the assay in the lower TRAb range.

The aim of this study was to develop an assay to selectively detect high-affinity components among TRAb. Using an rhTSHR-coated tube system, a 1 step TRAb assay method was developed that included 1) co-incubation with (125)I-bTSH, 2) a 50 microl serum sample, 3) an increased incubation volume (450 microl), and 4) a 1 hour incubation time. Sixty-one TRAb positive Graves' sera were studied. When the regular TRAb assay (Reg) results were quantitatively compared to the 1 step assay (1 step) results, certain dispersions and overestimations using the latter were seen. Further, some 1 step positive results were observed in the low Reg range. Overestimations were considered mostly due to the differences between TRAb standard and patients' serum TRAb in the binding competition against co-incubated (125)I-bTSH, which was shown from a modified assay mimicking the 1 step conditions. Therefore, the 1 step results were decided to be expressed by % inhibition against (125)I-bTSH. As for data dispersions, TRAb absorptions during the regular 1st incubation were studied. Individually, the absorption rates varied from 11 to 69%, and higher absorptions were observed in lower Reg range, especially in those negative by the 1 step. Observed 1 step positive results in the low Reg range were of interest, and 1 step/Reg ratios were calculated. The ratios with 1 step negative samples were significantly lower than those of 1 step positive samples. In conclusion, the 1 step assay was proved to detect a particular and biologically active TRAb, especially in those with low TRAb. The clinical significance of the 1 step results should be of future interest.

Antibody Affinity↗
PubMed2004

Hypertrophy, fibrosis, and sudden cardiac death in response to pathological stimuli in mice with mutations in cardiac troponin T.

BACKGROUND: Transgenic mouse models expressing a missense mutation (R92Q) or a splice donor site mutation (trunc) in the cardiac troponin T (cTnT) model familial hypertrophic cardiomyopathy (FHC) in humans. Although males from these strains share the unusual property of having significantly smaller ventricles and cardiac myocytes, they differ with regard to systolic function, fibrosis, and gene expression. Little is known about how these phenotypes affect the responses to additional pathological stimuli. METHODS AND RESULTS: We tested the ability of hearts of both sexes of wild-type and mutant mice to respond to defined pathological, pharmacological, hypertrophic stimuli in vivo. Hearts of mutant cTnT models of both sexes were able to undergo hypertrophy in response to at least one stimulus, but the extent differed between the 2 mutants and was sex specific. Interestingly, the trunc-mutant mouse heart was resistant to the development of fibrosis in response to pharmacological stimuli. Stimulation with 2 adrenergic agonists led to sudden cardiac death of all male but not female mutant animals, which suggests altered adrenergic responsiveness in these 2 models of FHC. CONCLUSIONS: Hypertrophic signaling is differentially affected by distinct mutations in cTnT and is sex modified. Hearts can respond with either an augmented hypertrophic and fibrotic response or a diminished hypertrophy and resistance to fibrosis. Sudden cardiac death is related to adrenergic stress and is independent of the development of fibrosis but occurred only in male mice. These results suggest that patients with certain TnT mutations may respond to certain pathological situations with a worsened phenotype.

Adrenergic alpha-Agonists↗
PubMed2004

Molecular determinants for cyclic nucleotide binding to the regulatory domains of phosphodiesterase 2A.

Binding of cGMP to the GAF-B domain of phosphodiesterase 2A allosterically activates catalytic activity. We report here a series of mutagenesis studies on the GAF-B domain of PDE2A that support a novel mechanism for molecular recognition of cGMP. Alanine mutations of Phe-438, Asp-439, and Thr-488, amino acids that interact with the pyrimidine ring, decrease cGMP affinity slightly but increase cAMP affinity by up to 8-fold. Each interaction is required to provide for cAMP/cGMP specificity. Mutations of any of the residues that interact with the phosphate-ribose moiety or the imidazole ring abolish cGMP binding. Thus, residues that interact with the pyrimidine ring collectively control cAMP/cGMP specificity, whereas residues that bind the phosphate-ribose moiety and imidazole ring are critical for high affinity binding. Similar decreases in binding were found for mutations made in a bacterially expressed GAF-A/B plus catalytic domain construct. Because these constructs had very high catalytic activity, it appears that these mutations did not cause a global denaturation. The affinities of cAMP and cGMP for wild-type GAF-B alone were approximately 4-fold greater than for the holoenzyme, suggesting that the presence of neighboring domains alters the conformation of GAF-B. More importantly, the PDE2A GAF-B, GAF-A/B, GAF-A/B+C domains, and holoenzyme all bind cGMP with much higher affinity than has previously been reported. This high affinity suggests that cGMP binding to PDE2 GAF-B activates the enzyme rapidly, stoichiometrically, and in an all or none fashion, rather than variably over a large range of cyclic nucleotide concentrations.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2004

Purification and molecular cloning of a major allergen from Anisakis simplex.

A heat-stable allergen with a molecular weight of 21 k was purified from larvae of the nematode Anisakis simplex by gel filtration, anion-exchange FPLC and reverse-phase HPLC. When analyzed by immunoblotting and ELISA, seven of eight patient sera reacted to the 21 k allergen, demonstrating that this protein is a major allergen of A. simplex. A full-length cDNA encoding the 21 k allergen was cloned by a combination of 3'RACE and screening of an expression library with DIG-labeled DNA probes. The precursor of the 21 k allergen was judged to be composed of a signal peptide (23 residues) and a mature protein (171 residues). As compared to the N-terminal amino acid sequence (up to the 17th residue) of Ani s 1 previously identified as the major allergen, the 21 k allergen has only one replacement, suggesting that the 21 k allergen belongs to the same protein family of Ani s 1. Although the 21 k allergen was found to have 30-40% sequence identity with Kunitz-type trypsin inhibitor domain containing hypothetical proteins of Caenorhabditis elegans, it lacked inhibitory activity against trypsin. The 21 k allergen was successfully expressed in Escherichia coli as a GST-fusion protein showing reactivity with IgE in patient sera.

Allergens↗
PubMedDate not supplied

Helium leak test for sterility assurance of a sealed bag. II: Establishing a test method for the manufacturing process.

To establish a simpler and more reliable method for retaining the aseptic condition of freeze-dried bulk product of a drug substance, a helium leak test method was developed. The bulk product is for the new kit system for infusion of our antibiotic product. In manufacturing the kit system, the bulk product needs to be transported outside of the aseptic area. We had to use a proper container to enclose the bulk product under aseptic conditions and establish an appropriate method for sterility assurance of the container. We decided to use a flexible aluminum laminate bag as a container and to seal it in a polyethylene bag. To detect tears or pinholes in the bag, a helium leak test was considered. As a tear model, a pinhole of known diameter was made in the aluminum laminate bag which was then filled with helium and sealed in a polyethylene bag. Helium leaking from the pinholes was measured with a helium leak detector, and leakage from a pinhole of more than 50 microm in the aluminum laminate bag could be detected. The amount of leakage was strongly affected by the pinhole diameter, and we developed a scientific approach for measuring leakage using the Poiseiulle Equation. The detection sensitivity of our method was enough to retain an aseptic condition inside the aluminum laminate bag, confirmed by the results of the process simulation test using our helium leak test. We concluded that our helium leak test was useful for sterility assurance of the bulk product sealed in the aluminum laminate bag in the manufacturing process of our kit system for infusion of our antibiotic product.

Quality Control↗