239 research outputs found

    Stability Optimization of Positive Semi-Markov Jump Linear Systems via Convex Optimization

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    In this paper, we study the problem of optimizing the stability of positive semi-Markov jump linear systems. We specifically consider the problem of tuning the coefficients of the system matrices for maximizing the exponential decay rate of the system under a budget-constraint. By using a result from the matrix theory on the log-log convexity of the spectral radius of nonnegative matrices, we show that the stability optimization problem reduces to a convex optimization problem under certain regularity conditions on the system matrices and the cost function. We illustrate the validity and effectiveness of the proposed results by using an example from the population biology

    ゼニゴケ葉緑体遺伝子と相同性を持つラン藻 Synechocystis PCC6803株のORF326、frxC およびORF469を標的にした変異の導入

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    ORF326, frxC and ORF469 of a transfomable cynobacterium, Synechcystis PCC6803, have sequence similarity with ORF465 on the choroplast genome of a livewort, Marchantia polymorpha, respectively. To elucidate their functions,targeted mutagenesis was performed by transformation with clened DNA in which the ORF was disrupted by insertion of a kanamycin resistancen gene cassette.Streak-purifications of a single colony of each transformant were repeatde to segregate homozygous mutants for disrupted copies, because Synechocystis PCC6803 was reported to have approximately 10 chromosomal DNA copies. Southern blot analysis revealed that mutants for ORF326 had not only disrupted ORF326 copies but also wild type ORF326 copies. This suggests that ORF326 is indispensable for growth under the mixotrophic growth condition used. However, mutants for frxC and mutants for ORF469 had only mutated copies, indicating that they dispensable for growth. Growth and chlorophyll a content of an ORF469-disrupted mutant were compared and chlorophyll a content of an ORF469-disrupted mutant were compared to those of wild type under mixotrophic growth condition, but no significant difference was detected. This indicates that ORF469 is required for neither normal growth nor chlorophyll biosynthesis under thie condition.ゼニゴケ葉緑体ORF316、frxCおよびORFと相同性を持つ、形質転換型ラン藻Synechocystis PCC6803株のORF326、frxCおよびORF469の機能についての情報を得るため、これらの欠損株の作製を行った。コード領域にカナマイシン耐性遺伝子カセットを挿入することにより不活性化された変異型のORF(オーブンリーディングフレーム)を持つプラスミドを用いてSynechocystis PCC6803株の形質転換を行い、カナマイシンを含む培地で選抜した。Synechocystis PCC6803株は約10コピーのクロモソームを持つが、サザンブロット解析の結果、ORF326については、変異型と野生型のORF326の双方を持つ株しか得られず、増殖に必要と推測された。一方frxCおよびORF469については、ともに全て変異型に置き換わった株が得られ、増殖には必要ないことが示された。さらにORF469欠損株を光照射下で培養し、増殖速度とクロロフィルa濃度を測定したが、いずれも野生株とほぼ同じであり、ORF469は、この条件下では、増殖やクロロフィル生合成に必要ないと推察された

    骨転移を有しない前立腺がん患者へのアンドロゲン除去療法による骨粗鬆症に対する経口ビスフォスフォネート製剤の予防効果について

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    We studied the short-term efficacy of alendronate, an oral bisphosphonates, on bone mineral density (BMD) during androgen deprivation therapy (ADT) in 45 nonmetastatic prostate cancer patients at the beginning of ADT (treatment group). All received alendronate five mg daily from the initiation of ADT. Lumber BMD was evaluated by dual energy X-ray absorptiometry, at baseline and after six months of treatment. Historical data on 24 patients with prostate cancer who received ADT without bisphosphonate administration were studied as controls (control group). BMD decreased in 13.9 and 45.8% of the patients in the treatment and control groups, respectively. Mean BMD changes in the lumber spine were +1.6 +/- 3.0% in the treatment group and -1.1 +/- 2.7% in the control group (p = 0.006). No pathological fractures occurred during the study period. No severe adverse effects were observed, but three patients could not continue alendronate treatment because of adverse events. Despite the short-term of this evaluation, our results showed that oral alendronate is an effective and safe treatment for preventing bone loss and increasing BMD in patients receiving ADT for prostate cancer.目的:アンドロゲン除去療法は骨塩減少とそれに伴う病的骨折の潜在的な危険因子である。点滴ビスフォスフォネート製剤はアンドロゲン除去療法を受けている前立腺がん患者に対する骨塩量の減少を予防することが示されているが経口ビスフォスフォネート製剤については評価されていない。今回, われわれは経口ビスフォスフォネート製剤の1つであるアレンドン酸を骨転移を有しない前立腺がん患者に投与して骨塩量を測定し短期間での効果を検討した。対象と方法:治療群として45人の骨転移を有しない前立腺がん患者について検討した。アレンドロン酸を1日5mg経口投与し治療前, 治療半年後に腰椎の骨塩量を測定し比較検討した。対照群として24人の骨転移を有しない前立腺がん患者についても同様に検討を行った。結果:骨塩量の減少は治療群で13.9%, 対照群で45.8%に見られた。腰椎における骨塩量の変化は治療群で平均1.6%, 対照群で-1.1%であった(p=0.006)。治療期間内において病的骨折は認められず, 有害事象として重篤なものは認めなかったが副作用のため3例が内服継続困難であった。結語:短期間の検討であるにもかかわらず経口ビスフォスフォネート製剤であるアレンドロン酸は前立腺がん患者に対するアンドロゲン除去療法による骨塩量減少を予防するのに有効で安全な治療法であることが示唆された。(著者抄録

    Whole Blood Interferon-Gamma Assay for Baseline Tuberculosis Screening among Japanese Healthcare Students

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    BACKGROUND: The whole blood interferon-gamma assay (QuantiFERON-TB-2G; QFT) has not been fully evaluated as a baseline tuberculosis screening test in Japanese healthcare students commencing clinical contact. The aim of this study was to compare the results from the QFT with those from the tuberculin skin test (TST) in a population deemed to be at a low risk for infection with Mycobacterium tuberculosis. METHODOLOGY/PRINCIPAL FINDINGS: Healthcare students recruited at Okayama University received both the TST and the QFT to assess the level of agreement between these two tests. The interleukin-10 levels before and after exposure to M tuberculosis-specific antigens (early-secreted antigenic target 6-kDa protein [ESAT-6] and culture filtrate protein 10 [CFP-10]) were also measured. Of the 536 healthcare students, most of whom had been vaccinated with bacillus-Calmette-Guérin (BCG), 207 (56%) were enrolled in this study. The agreement between the QFT and the TST results was poor, with positive result rates of 1.4% vs. 27.5%, respectively. A multivariate analysis also revealed that the induration diameter of the TST was not affected by the interferon-gamma concentration after exposure to either of the antigens but was influenced by the number of BCG needle scars (p = 0.046). The whole blood interleukin-10 assay revealed that after antigen exposure, the median increases in interleukin-10 concentration was higher in the subgroup with the small increase in interferon-gamma concentration than in the subgroup with the large increase in interferon-gamma concentration (0.3 vs. 0 pg/mL; p = 0.004). CONCLUSIONS/SIGNIFICANCE: As a baseline screening test for low-risk Japanese healthcare students at their course entry, QFT yielded quite discordant results, compared with the TST, probably because of the low specificity of the TST results in the BCG-vaccinated population. We also found, for the first time, that the change in the interleukin-10 level after exposure to specific antigens was inversely associated with that in the interferon-gamma level in a low-risk population

    Percutaneous coronary intervention strategy for acute coronary syndrome caused by spontaneous coronary artery dissection for relieving ongoing ischemia—Case series and literature review

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    AbstractAlthough spontaneous coronary artery dissection (SCAD) is one of the causes of acute coronary syndrome (ACS) or sudden cardiac death, its standard management, especially primary percutaneous coronary intervention (PCI) in ACS patients with ongoing ischemia, has not been established. We experienced three ACS patients with SCAD who were treated with a different strategy of primary PCI. Each PCI strategy led to different clinical and procedural results. We describe here such PCI strategies and results, and also discuss the literature regarding primary PCI strategies for SCAD-induced ACS patients with ongoing ischemia.<Learning objective: SCAD is a cause of ACS. However, the treatment strategy of primary PCI for SCAD has not been fully investigated. We used different PCI strategies for three SCAD patients with ongoing ischemia. Our case series suggested that plain old balloon angioplasty is an acceptable option to avoid coronary stenting because the majority of patients were young menstruating women. Coronary vasospasm might be associated with SCAD. Treatment with vasodilators could be a potential pharmacological option for avoiding recurrence of SCAD.

    Clinical benefit of readministration of gefitinib for initial gefitinib-responders with non-small cell lung cancer

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    BACKGROUND: Gefitinib, an oral agent of epidermal growth factor receptor tyrosine kinase inhibitor, has a certain efficacy against non-small cell lung cancer (NSCLC). Several predictive factors of gefitinib sensitivity have been well described. However, few studies have investigated the clinical features of gefitinib-responders. In the present study, we analyzed the response and disease progression of primary and metastatic lesions to gefitinib in responders and the results of gefitinib readministration following temporary cessation of gefitinib upon progression of initial gefitinib treatment and other treatments. METHOD: We retrospectively evaluated the clinical courses of 27 NSCLC patients who received gefitinib and achieved either a complete or partial response. RESULTS: The best-response rate and disease-control rate against the initial chemotherapy for the gefitinib-responders were 27.3% and 77.3%, respectively. Favorable efficacy was observed in the primary lesion and metastases to the lung, liver and brain, while there was no obvious effect on bone metastasis. The primary lesion and intrapulmonary metastasis were the sites of major recurrence. Median progression-free survival was 13.8 months, median duration of gefitinib treatment was 17.0 months and median overall survival was 29.2 months. Some of the patients who experienced disease progression after responding to gefitinib were again sensitive to readministration of gefitinib following temporary cessation of gefitinib and other treatments. CONCLUSION: Patients may still be expected to have prolonged survival if they once responded to gefitinib and then underwent various subsequent treatments followed by readministration of gefitinib. These findings might provide valuable information for the management of gefitinib-responders
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