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To investigate whether dantrolene (DAN), cardiac ryanodine receptor (RyR2) stabilizer, improves impaired diastolic function in an early pressure-overloaded hypertrophied heart, pressure-overload hypertrophy was induced by transverse aortic constriction (TAC) in mice. Wild-type (WT) mice were divided into four groups: sham-operated mice (Sham), sham-operated mice treated with DAN (DAN+Sham), TAC mice (TAC), and TAC mice treated with DAN (DAN+TAC). The mice were then followed up for 2 weeks. Left ventricular (LV) hypertrophy was induced in TAC, but not DAN+TAC mice, 2 weeks after TAC. There were no differences in LV fractional shortening among the four groups. Catheter tip micromanometer showed that the time constant of LV pressure decay, an index of diastolic function, was significantly prolonged in TAC but not in DAN+TAC mice. Diastolic function was significantly impaired in TAC, but not in DAN+TAC mice as determined by cell shortening and Ca^{2+} transients. An increase in diastolic Ca^{2+} leakage and a decrease in calmodulin (CaM) binding affinity to RyR2 were observed in TAC mice, while diastolic Ca^{2+} leakage improved in DAN+TAC mice. Thus, DAN prevented the progression of hypertrophy and improved the impairment of LV relaxation by inhibiting diastolic Ca^{2+} leakage through RyR2 and the dissociation of CaM from RyR2.
Creators : Chang Yaowei | Kobayashi Shigeki | Yano Yasutake | Uchida Tomoyuki | Nawata Junya | Fujii Shohei | Nakamura Yoshihide | Suetomi Takeshi | Uchinoumi Hitoshi | Oda Tetsuro | Yamamoto Takeshi | Yano Masafumi Publishers : Yamaguchi University School of Medicine Date Issued : 2023-06
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is caused by a single point mutation in the cardiac type 2 ryanodine receptor (RyR2). Using knock-in mouse (KI) model (R2474S/+), we previously reported that a single point mutation within the RyR2 sensitized the channel to agonists, primarily mediated by defective inter-domain interaction within the RyR2 and subsequent dissociation of calmodulin (CaM) from the RyR2. Here, we examined whether CPVT can be genetically rescued by enhancing the binding affinity of CaM to the RyR2. We first determined whether there was a possible amino-acid substitution within the CaM-binding domain in the RyR2 (3584-3603) that can enhance its binding affinity to CaM, and found that V3599K substitution showed the highest binding affinity of CaM to CaM-binding domain. Hence, we generated a heterozygous KI mouse model (V3599K/+) with a single amino acid substitution in the CaM-binding domain of the RyR2, and crossbred it with the heterozygous CPVT –associated R2474S/+ KI mouse to obtain a double heterozygous R2474S/V3599K KI mouse model. The CPVT phenotypes, bidirectional or polymorphic ventricular tachycardia, were inhibited in the R2474S/V3599K mice. Thus, enhancement of the CaM binding affinity of the RyR2 is essential to prevent CPVT-associated arrhythmogenesis.
Creators : Nakamura Yoshihide | Yamamoto Takeshi | Kobayashi Shigeki | Yano Masafumi Publishers : Yamaguchi University School of Medicine Date Issued : 2023-06
Abstract Purpose: The purpose of this study was to investigate the effects of two different postures (sitting and standing) and three different ambient temperatures (10℃, 20℃, and 30℃) on heart rate variability (HRV) among healthy young adults. Methods: Twelve young adult volunteers (males 6, females 6) were recruited. Following acclimatization to any the room temperature (10℃, 20℃ or 30℃), 5-min measurements of HRV were conducted in sitting and standing postures of the subjects. Results: Compared to the sitting posture, measurements obtained in the standing posture revealed a significant decrease in high-frequency power/HF, root mean square of successive differences between RR intervals, standard deviation of Poincaré plot perpendicular to the line-of-identity or SD1 and SD1/standard deviation of Poincaré plot along the line-of-identity or SD2, and a significant increase in lowfrequency power/LF and LF/HF under all experimental conditions (p<0.05 to 0.005). Majority of HRV parameters showed significant differences while the values obtained under 10℃ were compared with 20℃ and 30℃ conditions, respectively (p<0.05 to 0.001). Conclusions: Our findings suggest the predominance of sympathetic tone in the standing compared with sitting posture. Furthermore, colder conditions caused a predominance of the parasympathetic activity in both sitting and standing postures, and such effects of ambient temperature on the sympathovagal balance were stronger in the latter posture.
Creators : Wada Sunao | Mahbub MH | Nakagami Yuki | Hase Ryosuke | Yamaguchi Natsu | Takahashi Hidekazu | Saito Hiroyuki | Shimokawa Junki | Watanabe Rie | Harada Noriaki | Tanabe Tsuyoshi Publishers : Yamaguchi University School of Medicine Date Issued : 2022-12
Abstract Objectives: This study examined the short-term outcomes of endovascular therapy (EVT) with the GORE VIABAHN VBX (VBX) which is a balloon-expandable covered stent in patients with aortoiliac occlusive disease (AIOD) and acute limb ischemia (ALI). Methods: This was a single-center retrospective review of patients with AIOD and ALI who underwent EVT with the VBX between December 2018 and January 2021. Primary, assisted, and secondary patency rates were assessed, along with 30-day mortality rates. Results: Twenty-two patients underwent EVT with the VBX; 18 patients had AIOD, whereas 4 had ALI. The incidence of TransAtlantic Intersociety Classification II D lesions was 50% (n=9). Technical success was 100%. One patient with unilateral common iliac artery stenosis developed an intraoperative dissection of the distal edge of the VBX, which required an additional self-expanding VIABAHN stent on the distal edge of the VBX. The primary patency rate at 24 months was 100%. No patients required additional target vessel treatment at a median follow-up of 10 months (range, 1-27). EVT was also successful in the four patients with ALI, who had no complications of the target vessel. Conclusion: The present study demonstrated that EVT with the VBX is effective for AIOD and ALI.
Creators : Mizoguchi Takahiro | Morikage Noriyasu | Ike Soichi | Nagase Takashi | Samura Makoto | Harada Takasuke | Kurazumi Hiroshi | Suzuki Ryo | Suehiro Kotaro | Hamano Kimikazu Publishers : Yamaguchi University School of Medicine Date Issued : 2022-12
A novel mutation in IKBKG gene in a female child with incontinentia pigmenti
The bulletin of the Yamaguchi Medical School Volume 69 Issue 1-2
Incontinentia pigmenti (IP; OMIM# 308300) is a rare inherited disease caused by a mutation of IKBKG, which is also known as NEMO, located on Xq28. IP patients usually present with abnormalities of skin, eyes, nails and central nervous system. The neurological damege, which occur usually from neonatal through the early infantile period, leads to neulogical complication such as development retardation, motor paralysis and epilepsy. However, there has been little study done concerning the effect of therapy for the neural abnormalities. We have investigated the clinical findings in a female IP case with a novel mutation of IKBKG for six years due to disclosing the neurological prognosis and the immunological features. It is hoped that the present study will contribute to a better management of IP patients.
Creators : Sakata Yasufumi | Hirano Reiji | Yasudo Hiroki | Shimomura Yutaka | Takada Hidetoshi | Suehiro Yutaka | Ohga Shouichi | Hasegawa Shunji Publishers : Yamaguchi University School of Medicine Date Issued : 2022-06
The hippocampal dentate gyrus has been identified to play a critical role in maintaining contextual memory in many mammalian species. To evaluate learninginduced synaptic plasticity of granule cells, we subjected male rats to an inhibitory avoidance (IA) task and prepared acute hippocampal slices. In the presence of 0.5 μM tetrodotoxin, we recorded miniature excitatory post synaptic currents (mEPSCs) and inhibitory post synaptic currents (mIPSCs) in male rats experiencing four groups: untrained, IA-trained, unpaired, and walk-through. Compared with the untrained, IA-trained, unpaired, and walk-through groups, the unpaired group significantly enhanced mean mEPSC amplitudes, suggesting the experience-induced plasticity at AMPA receptor-mediated excitatory synapses. For inhibitory synapses, both unpaired and walk-through groups significantly decreased mean mIPSC amplitudes, showing the experience-induced reduction of postsynaptic GABAA receptor-mediated currents. Unlike the plasticity at CA1 synapses, it was difficult to explain the learning- specific plasticity at the synapses. However, overall multivariate analysis using four variables of mE(I)PSC responses revealed experience-specific changes in the diversity, suggesting that the diversity of excitatory/inhibitory synapses onto granule cells differs among the past experience of animals include the learning. In comparison with CA1 pyramidal neurons, granule cells consistently showed greater amplitude and frequency of mE(I)PSCs. Fluctuation analysis further revealed that granule cells provide more postsynaptic AMPA receptor channels and greater single-channel current of GABAA receptors of than CA1 pyramidal neurons. These findings show functional differences between two types of principal cells in the hippocampus.
Creators : Han Thiri Zin | Sakimoto Yuya | Mitsushima Dai Publishers : Yamaguchi University School of Medicine Date Issued : 2022-06
Androgen receptor (AR)-signaling plays an important role in promoting tumor cell survival and the development of castration-resistant prostate cancer (CRPC). Androgen deprivation therapy is the basic therapeutic strategy for AR signaling blockade, but that effects wonʼt last long and most of metastatic prostate cancer show castration resistance. Recently, new agents, AR Axis Targeted agents (ARAT), have been developed. We have been developing our bench-to-bedside translational research to elucidate the mechanisms of drug resistance in prostate cancer. This review describes our investigational results and recent advances in CRPC with ARAT treatment strategy.
Creators : Matsumoto Hiroaki | Matsuyama Hideyasu Publishers : Yamaguchi University School of Medicine Date Issued : 2022-06
背景:顕微鏡的多発血管炎 (MPA) は全身臓器が障害される疾患である。しかしながら、MPA患者における心臓超音波検査(心エコー図検査)における指標の特徴については不明な点が多い。 目的:本研究は、単施設後ろ向き研究で、ステロイド療法の新規導入または再導入後2週間以内に心エコーを行ったMPA患者15名を対象とし、その心エコー所見の特徴について検討することを研究の目的とした。30人の年齢・性別をマッチさせた心疾患のないコントロール群と比較検討した。 方法と結果:左室径、左室駆出率、拡張早期僧帽弁輪最大移動速度 (e’) に2群間で有意差は認めなかった。一方、MPA群では左房径、左房容積係数が有意に高く、左室流入血流速波形 (TMF) の早期拡張期充満速度(E波)と肺静脈流入拡張期血流速度 (D波) の高さ、三尖弁における収縮期右室-右房最大圧較差も有意に高く、TMFのE波の減速時間 (DCT) は短縮していた。血清CRPはTMFのE波高、E/A比およびDCTと相関が見られた。今回の研究では、MPA患者におけるe’の有意な低下がみられなかったことから、左室弛緩能の低下よりはむしろ左室スティフネスの上昇によって左室拡張機能低下が生じ、結果として左房拡大が生じている可能性が示唆された。 結語:急性期MPA患者では左室拡張機能低下によると考えられる左房拡大を生じていた。MPA患者、特に強い炎症反応を伴う患者では、心機能評価を行うことが重要であることが示唆された。
Creators : 木下 奈津
【背景】全層性治癒(Transmural healing healing; TH)は、クローン病の新たな治療標的として注目されているが、日本ではTHに関する臨床データはほとんどない。我々は、クローン病のモニタリング法として低被曝線量CTエンテログラフィ(CTE)を導入し、CTEによるTHの評価をレトロスペクティブに検討した。【方法】2009年 1月から2021年3月までに当院で低被曝線量CTEを施行したクローン病患者のうち、2週間以内に大腸内視鏡検査またはバルーン内視鏡検査を施行した122例を対象とした。放射線検査と内視鏡検査の結果は、それぞれ放射線科医と消化器内視鏡医が独立して検討した。CTEと内視鏡検査の診断の一致率を算出した。【結果】26名(21.3%)のクローン病患者がTHを達成し、カッパ係数は0.743と2人の放射線科医の間でかなりの一致が見られた。TH群と非TH群の比較では、クローン病活動指数(Crohn’s Disease Activity Index ; CDAI )(P値 = 0.02)、内視鏡的治癒率(P値 < 0.001)、血清アルブミン(P値 = 0.043)、血清C反応性蛋白(P値 = 0.018)に有意差が認められた。122名の患者のうち、69名(56.5%)はCTEの診断と内視鏡検査が一致し、22名(18.0%)はTHと内視鏡の両方の治癒を達成した。【結論】本研究は、日本における低被曝線量CTEによるクローン病のリアルワードデータを示すものである。本研究で用いたTHの基準はカッパ係数が高く、多くの施設で再現性を持って用いることができると考えられる。
Creators : 藤村 寛之
【背景】近年、歯周炎や歯肉炎に関連する嫌気性グラム桿菌であるFusobacterium nucleatum (F. nucleatum) は大腸がんの発生や進行に関与することが報告されている。この菌の制御が大腸がんの予防につながる可能性があると考え、深紫外線発光ダイオード (DUV-LED) によるF. nucleatumの殺菌効果を検討した。【方法】DUV-LEDのF. nucleatumに対する殺菌効果を定性的、定量的に評価した。ピーク波長が265nmと280nmの2種類のDUV-LEDを使用した。F. nucleatumのDNAに対するダメージは、シクロブタンピリミジン二量体(CPD)とピリミジンピリミドン光生成物 (6-4PP) の生成で評価した。【結果】DUV-LEDでの265nmまたは280nmの波長を3分間照射したところ、コロニーの成長は観察されなかった。265nmのDUV-LED光照射下におけるF. nucleatumの生存率は10秒照射で0.0014%、20秒照射で0%に低下した。同様に、280nmのDUV-LED光照射では,10秒照射で0.00044%、20秒照射で0%に低下した。DUV-LEDから35mmの距離での放射照度は、265nmのLEDで0.265mW/cm^2、280nmのLEDでは0.415mW/cm^2であった。従って、致死量を示す放射エネルギーは265nm LEDは5.3mJ/cm^2、280nm LEDは8.3mJ/cm^2であった。265nmと280nmのDUV-LED光をF. nucleatumに照射した際のCPDと6-4PPの量はそれぞれ6.548ng/μg、1.333ng/μgであった。【結論】DUV-LED光は、F. nucleatumに対して、ピリミジン二量体を形成することにより殺菌効果を発揮した。
Creators : 伊藤 駿介
前身に投与された治療薬が脳組織実質に到達するには、神経組織の血管により形成される血液脳関門を通過する必要がある。そのため、組織への損傷を最小限に抑えて血液脳関門を開くことができれば、難治性神経疾患の治療法開発に大きな進展をもたらすことが期待される。本研究では、血液脳関門を形成する血管内皮細胞に発現するBasiginに着目し、その内因性リガンドであるCyclophilin A (CypA) を用いて、血液脳関門機能を人為的に制御することを目的とした。マウス脳血管内皮細胞株を用いたin vivo解析により、CypAの投与がBasiginを介して血液脳関門機能を低下させること、それにより脳実質へ効率的に薬物を送達できることを示した。単層培養された血管内皮細胞において、CypAはタイト結合構成分子の一つであるClaudin-5を一過性かつ可逆的に細胞膜から消失させて、バリアー機能を低下させることを見出した。また、マウスへのCypAの単回静脈内投与では血液脳関門が一定期間開いた後、自発的に元の状態へ回復することが示され、そしてその限定された機関において、全身投与された水溶性薬物Doxorubicinが脳組織実質へ送達されることが明らかとなった。本研究の結果は、CypAの静脈内投与によって、脳実質への薬物送達を自在にコントロールできることを示しており、難治性神経疾患に対する治療法確立に向けた重要な成果であると考えられる。
Creators : 本田 成美
The hippocampal dentate gyrus has been identified to play a critical role in maintaining contextual memory in many mammalian species. To evaluate learning-induced synaptic plasticity of granule cells, we subjected male rats to an inhibitory avoidance (IA) task and prepared acute hippocampal slices. In the presence of 0.5 µM tetrodotoxin, we recorded miniature EPSCs in male rats experiencing four groups: untrained, IA-trained, unpaired, and walk-through. Compared with the untrained, IA-trained, unpaired, and walk-through groups, the unpaired group significantly enhanced mean mEPSC amplitudes, suggesting the experience-induced plasticity at AMPA receptor-mediated excitatory synapses. For inhibitory synapses, both unpaired and walk-through groups significantly decreased mean mIPSC amplitudes, showing the experience-induced reduction of postsynaptic GABA_A receptor-mediated currents. Unlike the plasticity at CA1 synapses, it was difficult to explain the learning-specific plasticity at the synapses. However, overall multivariate analysis using four variables of mE(I)PSC responses revealed experience-specific changes in the diversity, suggesting that the diversity of excitatory/inhibitory synapses onto granule cells differs among the past experience of animals include the learning. In comparison with CA1 pyramidal neurons, granule cells consistently showed greater amplitude and frequency of mE(I)PSCs. Fluctuation analysis further revealed that granule cells provide more postsynaptic AMPA receptor channels and greater single-channel current of GABA_A receptors of than CA1 pyramidal neurons. These findings show functional differences between two types of principal cells in the hippocampus.
Creators : Han Thiri Zin
Cardiovascular diseases are the leading cause of mortality and disability worldwide. We have previously found that sphingosylphorsphorylcholine (SPC) is the key molecule leading to vasospasm. We have also identified the SPC/Src family protein tyrosine kinase Fyn/Rho-kinase (ROK) pathway as a novel signaling pathway for Ca^{2+}-sensitization of vascular smooth muscle (VSM) contraction. The present study aimed to investigate whether hesperetin can inhibit the SPC-induced contraction with little effect on 40 mM K^+-induced Ca^{2+}-dependent contraction and to elucidate the underlying mechanisms. Hesperetin significantly inhibited the SPC-induced contraction of porcine coronary artery smooth muscle strips with little effect on 40 mM K^+-induced contraction. Hesperetin blocked the SPC-induced translocation of Fyn and ROK from the cytosol to the membrane in human coronary artery smooth muscle cells (HCASMCs). SPC decreased the phosphorylation level of Fyn at Y531 in both VSMs and HCASMCs and increased the phosphorylation levels of Fyn at Y420, myosin phosphatase target subunit 1 (MYPT1) at T853 and myosin light chain (MLC) at S19 in both VSMs and HCASMCs, which were significantly suppressed by hesperetin. Our results indicate that hesperetin inhibits the SPC-induced contraction at least in part by suppressing the Fyn/ROK pathway, suggesting that hesperetin can be novel drug to prevent and treat vasospasm.
Creators : Lu Qian
Creators : Saeki Issei Publishers : 山口大学医学会 Date Issued : 2021-12-02
Creators : Honda Takeshi Publishers : 山口大学医学会 Date Issued : 2021-12-02
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