Inhibition of Phospholipase A2 and Platelet Aggregation by Grycyrrhizin, an Anti-inframmation Drug

We studied the effect of glycyrrhizin, a compound known as an anti-inflammatory and antiallergic drug, on the membrane permeability change induced by phospholipase A2 (PLA2) and on platelet aggregation. Glycyrrhizin was found to inhibit the PLA2-induced carboxyfluorescein (CF) release from D,L-dipalmitoyl phosphatidylcholine (DPPC) liposomes. Part of this inhibitory effect of glycyrrhizin on PLA2 is accounted for by the physical state of the substrate, the DPPC liposome membrane. Glycyrrhizin also inhibited collagen-induced platelet aggregation in a concentration dependent manner, which may in part account for its inhibitory effect on PLA2.</p

Discovery of a Long-duration Superflare on a Young Solar-type Star EK Draconis with Nearly Similar Time Evolution for H alpha and White-light Emissions

Young solar-type stars are known to show frequent "superflares, " which may severely influence the habitable worlds on young planets via intense radiation and coronal mass ejections. Here we report an optical spectroscopic and photometric observation of a long-duration superflare on the young solar-type star EK Draconis (50-120 Myr age) with the Seimei telescope and Transiting Exoplanet Survey Satellite. The flare energy 2.6 x 10³⁴ erg and white-light flare duration 2.2 hr are much larger than those of the largest solar flares, and this is the largest superflare on a solar-type star ever detected by optical spectroscopy. The H alpha emission profile shows no significant line asymmetry, meaning no signature of a filament eruption, unlike the only previous detection of a superflare on this star. Also, it did not show significant line broadening, indicating that the nonthermal heating at the flare footpoints is not essential or that the footpoints are behind the limb. The time evolution and duration of the H alpha flare are surprisingly almost the same as those of the white-light flare, which is different from general M-dwarf (super-)flares and solar flares. This unexpected time evolution may suggest that different radiation mechanisms than general solar flares are predominant, such as: (1) radiation from (off-limb) flare loops and (2) re-radiation via radiative back-warming, in both of which the cooling timescales of flare loops could determine the timescales of H alpha and white light

ワルファリン ト アミオダロン オ ヘイヨウ シテイル ソウボウベン ケイセイ ジュツゴ カンジャ ニオイテ レモン カヒ オ ガンユウスル ミズ ノ ジョウヨウ ニヨリ シュッケツ ケイコウ オ クリカエシタ ト カンガエラレタ イチレイ

今回レモン果皮を用いた水を常用したことで出血傾向を繰り返したと考えられる症例を経験したため報告する。症例は61歳女性で、僧房弁狭窄症に対して11年前と4年前に僧帽弁形成術を施行された。発作性心房細動再発および軽度僧帽弁狭窄症に対してワルファリンおよびアミオダロンを処方し外来加療を続けていた。1年前に腹痛、下痢、血便、皮下出血を主訴に近隣病院の救急外来を受診され、感染性腸炎の診断で入院加療を受けた。入院時の血液検査でプロトロンビン時間 国際標準比(PT-INR)が 6.35と異常な延長を認めていた。退院後は当科外来へ通院再開したが、PT-INRの延長傾向が１ヶ月ほど続いた。今回、腹痛、下痢、血便、皮下出血が再発し当科外来を受診となった。血液検査にてPT-INR 4.14と延長を再度認めた。健康食品や嗜好品、生活習慣を含む生活歴を聴取したところ、1年前から初夏にレモン果皮を用いて飲用水を作成し頻回に飲んでいることが判明した。PT-INRが異常延長していた時期とレモン果皮が含まれる飲用水を常用していた時期が同じであったため、レモン果皮を用いた飲用水の常用によりPT-INRが異常延長し、出血傾向となったと考えられた。直ちにレモン果皮が含まれる水の飲用を中止させ、PT-INRは約1ヶ月のうちに治療域で安定した。以後PT-INRの異常延長および出血傾向は認められなくなった。We report a case of repeated bleeding tendencies due to regular use of lemon peel water. A 61-year-old woman underwent mitral valvuloplasty 11 and 4 years ago for mitral stenosis. She had recurrent paroxysmal atrial fibrillation and mild mitral stenosis after second surgery, and been administered with warfarin and amiodarone and continued outpatient treatment. One year ago, she visited the emergency department of a nearby hospital with chief complaints of abdominal pain, diarrhea, bloody stools, and subcutaneous bleeding, and she was hospitalized with a diagnosis of infectious enteritis. A blood test revealed the extremely elevated PT-INR value of 6.35. After she was discharged from the hospital, she returned to our outpatient clinic. The PT-INR prolongation trend had been continued for a month. This year, she visited our outpatient clinic because of recurrence of abdominal pain, diarrhea, bloody stools, and subcutaneous bleeding. A blood test showed the elevated PT-INR value of 4.14. Her social history was revealed that she had started to make water containing lemon peel and drunk it frequently in early summer for about one year. Since the time of extremely elevated PT-INR value and the time when she had started to drink the water with lemon peel frequently was the same, it was suspected that there was a causal relationship between them. After we stopped her from drinking the water with lemon peel immediately, the PT-INR value was normalized within in a month. Since then the extremely elevated PT-INR value has never been observed

Probable detection of an eruptive filament from a superflare on a solar-type star

太陽型星のスーパーフレアから噴出する巨大フィラメントを初検出 --昔の、そして今の惑星環境や文明に与える脅威--. 京都大学プレスリリース. 2021-12-10.Solar flares are often accompanied by filament/prominence eruptions (~10⁴ K and ~10¹⁰⁻¹¹ cm⁻³), sometimes leading to coronal mass ejections that directly affect the Earth’s environment. ‘Superflares’ are found on some active solar-type (G-type main-sequence) stars, but the filament eruption–coronal mass ejection association has not been established. Here we show that our optical spectroscopic observation of the young solar-type star EK Draconis reveals evidence for a stellar filament eruption associated with a superflare. This superflare emitted a radiated energy of 2.0 × 10³³ erg, and a blueshifted hydrogen absorption component with a high velocity of −510 km s⁻¹ was observed shortly afterwards. The temporal changes in the spectra strongly resemble those of solar filament eruptions. Comparing this eruption with solar filament eruptions in terms of the length scale and velocity strongly suggests that a stellar coronal mass ejection occurred. The erupted filament mass of 1.1 × 10¹⁸ g is ten times larger than those of the largest solar coronal mass ejections. The massive filament eruption and an associated coronal mass ejection provide the opportunity to evaluate how they affect the environment of young exoplanets/the young Earth6 and stellar mass/angular momentum evolution

Establishment of Functioning Human Corneal Endothelial Cell Line with High Growth Potential

Hexagonal-shaped human corneal endothelial cells (HCEC) form a monolayer by adhering tightly through their intercellular adhesion molecules. Located at the posterior corneal surface, they maintain corneal translucency by dehydrating the corneal stroma, mainly through the Na+- and K+-dependent ATPase (Na+/K+-ATPase). Because HCEC proliferative activity is low in vivo, once HCEC are damaged and their numbers decrease, the cornea begins to show opacity due to overhydration, resulting in loss of vision. HCEC cell cycle arrest occurs at the G1 phase and is partly regulated by cyclin-dependent kinase inhibitors (CKIs) in the Rb pathway (p16-CDK4/CyclinD1-pRb). In this study, we tried to activate proliferation of HCEC by inhibiting CKIs. Retroviral transduction was used to generate two new HCEC lines: transduced human corneal endothelial cell by human papillomavirus type E6/E7 (THCEC (E6/E7)) and transduced human corneal endothelial cell by Cdk4R24C/CyclinD1 (THCEH (Cyclin)). Reverse transcriptase polymerase chain reaction analysis of gene expression revealed little difference between THCEC (E6/E7), THCEH (Cyclin) and non-transduced HCEC, but cell cycle-related genes were up-regulated in THCEC (E6/E7) and THCEH (Cyclin). THCEH (Cyclin) expressed intercellular molecules including ZO-1 and N-cadherin and showed similar Na+/K+-ATPase pump function to HCEC, which was not demonstrated in THCEC (E6/E7). This study shows that HCEC cell cycle activation can be achieved by inhibiting CKIs even while maintaining critical pump function and morphology

Vascular RAGE transports oxytocin into the brain to elicit its maternal bonding behaviour in mice

金沢大学医薬保健研究域医学系Oxytocin sets the stage for childbirth by initiating uterine contractions, lactation and maternal bonding behaviours. Mice lacking secreted oxcytocin (Oxt -/-, Cd38 -/-) or its receptor (Oxtr -/-) fail to nurture. Normal maternal behaviour is restored by peripheral oxcytocin replacement in Oxt -/- and Cd38 -/-, but not Oxtr -/- mice, implying that circulating oxcytocin crosses the blood-brain barrier. Exogenous oxcytocin also has behavioural effects in humans. However, circulating polypeptides are typically excluded from the brain. We show that oxcytocin is transported into the brain by receptor for advanced glycation end-products (RAGE) on brain capillary endothelial cells. The increases in oxcytocin in the brain which follow exogenous administration are lost in Ager -/- male mice lacking RAGE, and behaviours characteristic to abnormalities in oxcytocin signalling are recapitulated in Ager -/- mice, including deficits in maternal bonding and hyperactivity. Our findings show that RAGE-mediated transport is critical to the behavioural actions of oxcytocin associated with parenting and social bonding.3082047