Kenji Tanaka

Juntendo University, Edo, Tōkyō, Japan

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Publications (4)8.85 Total impact

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    ABSTRACT: To date, numerous studies have searched for candidate molecules or clinical examination methods as potential biomarkers for monitoring intractable diseases, such as carcinomas. Evidence accumulated over the past decade shows that many proteolytic peptides appear in human humoral fluids, including peripheral blood, in association with an individual's health condition. Although an analysis of the whole peptide (the 'peptidome') using mass spectrometry is thought to be one of the most powerful and promising experimental approaches, it has failed to identify biomarkers in the clinical blood samples, presumably due to the methodological limitations. In general, commonly used techniques for proteomic analysis of blood require the removal of large amounts of serum/plasma proteins prior to mass spectrometry analysis, and this step seems to have resulted in the overlooking of important biomarkers during the analytical process. Here, we provide a brief overview of a new quantitative peptidomic analysis by a one-step direct transfer technology without depletion of major blood proteins. Using this technology, we herein report experimental data on serum peptidomic analysis for patients with pregnancy-induced hypertension as a clinical model. In addition, we refer to the potential utility of this approach for the monitoring of pathophysiological status in female reproductive system disorders in general.
    Journal of Obstetrics and Gynaecology Research 09/2013; · 0.84 Impact Factor
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    ABSTRACT: We have recently developed a new target plate (BLOTCHIP®) for MALDI-MS. An advantage of this procedure is that it does not require the lowering of protein concentrations in test samples prior to analysis. Accordingly, this new technology enables the detection of peptides present in blood samples, including those that would otherwise be adsorbed to abundant blood proteins and would thus escape detection. Using this technology, we analyzed the peripheral blood of patients with pregnancy-induced hypertension (PIH; the most common serious complication of pregnancy) to test a potential utility of the technology for monitoring of the pathophysiological status. In the present study, we found 23 characteristic peptides for PIH in the blood serum of pregnant women. Offline LC-MALDI MS/MS identified 7 of the 23 peptides as fragments derived from kininogen-1 (three peptides), fibrinogen-α, complement component C4-A/B, α-2-HS-glycoprotein and inter-α-trypsin inhibitor heavy chain H4. 2-D scatter plots with combinations of the peptides found in the present study can be grouped for pregnant women with/without PIH, which would be satisfactory reflected for their status. Additionally, the levels of most of these peptides found were significantly decreased by albumin/IgG depletion prior to BLOTCHIP® analysis in accordance with conventional proteomics procedures. These results indicated that BLOTCHIP® analysis can be applied for discovery study of PIH biomarker candidates.
    Proteomics 07/2011; 11(13):2727-37. · 4.43 Impact Factor
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    ABSTRACT: Human serum contains thousands of proteolytically derived low-molecular-weight peptide fragments (serum peptidome). The concept of utilizing the serum peptidome for cancer diagnosis has been developed. A pathological serum peptidome appears when the homeostatic balance between proteases and protease inhibitors is disrupted. We hypothesize if analyses of the serum peptidome are of diagnostic value as information on which molecules are disrupted, and the pathological course it will take in unknown pathological conditions and disseminated intravascular coagulation (DIC). We analyzed the serum peptidome in 3 stages (early stage, pre-DIC and DIC stages) in one patient with POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein and skin changes) syndrome, an intractable disease with unknown pathology, using a 1-dimensional gel electrophoresis/matrix-assisted laser desorption/ionization-mass spectrometry (1-DE/MS)-based rapid quantitative approach. A very large number of peptide fragments appeared in the DIC stage, compared to pre-DIC. In addition, we identified fragments of transthyretin (ALGISPFHEHAEVVFTANDSGPR, m/z 2451.18) and alpha1-antitrypsin (EDPQGDAAQKTDTSHHDQDHPTFN, m/z 2691.02) that significantly increased in the DIC stage, compared to those in the pre-DIC stage. Rapid analyses of the serum peptidome may lead to a diagnostic method that can predict on-going protease activated pathological conditions and help to decide on multilateral strategies including nutritional support and drug therapy.
    Medical Hypotheses 06/2009; 73(5):760-3. · 1.18 Impact Factor
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    ABSTRACT: We have developed a new target plate for matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). This target plate enables direct electric transfer of analytes from the 1-dimensional gel electrophoresis (1-DE) gel to the target plate in one step. Incorporated with a one-step direct transfer technique, this novel 1-DE/MALDI-MS (1-DE/MS) system eliminates staining, extracting, loading, and many other time-consuming intermediate processes, thereby greatly reducing analysis time while providing high throughput proteome analysis. Furthermore, in peptidome analysis, during the 1-DE step this system separates or removes the high molecular weight plasma proteins in blood and the various low molecular weight substances in tissue extracts, which interfere with mass spectrometry. This system can therefore be used for peptide profiling of any biological sample without special pretreatment. In view of these advantages, the 1-DE/MS system will greatly improve the usefulness of current peptidomic modalities in the discovery and validation of biomarker molecules in various body fluids and tissue extracts, permitting early detection, diagnosis, and treatment of diseases.
    Biochemical and Biophysical Research Communications 01/2009; 379(1):110-4. · 2.41 Impact Factor