Yuka Matsuki

Rectified Proton Grotthuss Conduction Across a Long Water-Wire in the Test Nanotube of the Polytheonamide B Channel

A hydrogen-bonded water-chain in a nanotube is highly proton conductive, and examining the proton flux under electric fields is crucial to understanding the one-dimensional Grotthuss conduction. Here, we exploited a nanotube-forming natural product, the peptide polytheonamide B (pTB), to examine proton conduction mechanisms at a single-molecule level. The pTB nanotube has a length of ∼40 Å that spans the membrane and a uniform inner diameter of 4 Å that holds a single-file water-chain. Single-channel proton currents were measured using planar lipid bilayers in various proton concentrations and membrane potentials (±400 mV). We found, surprisingly, that the current-voltage curves were asymmetric with symmetric proton concentrations in both solutions across the membrane (rectification). The proton flux from the C-terminal to the N-terminal end was 1.6 times higher than that from the opposite. At lower proton concentrations, the degree of rectification was attenuated, but with the addition of a pH-buffer (dichloroacetate) that supplies protons near the entrance, the rectification emerged. These results indicate that the permeation processes inside the pore generate the rectification, which is masked at low concentrations by the diffusion-limited access of protons to the pore entrance. The permeation processes were characterized by a discrete-state Markov model, in which hops of a proton followed by water-chain turnovers were implemented. The optimized model revealed that the water-chain turnover exhibited unusual voltage dependence, and the distinct voltage-dependencies of the forward and backward transition rates yielded the rectification. The pTB nanotube serves as a rectified proton conductor, and the design principles can be exploited for proton-conducting materials.

Reliability and validity of the Japanese translation of the DN4 Diagnostic Questionnaire in patients with neuropathic pain

BackgroundThe Douleur Neuropathique 4 questionnaire (DN4) is a simple and objective tool developed by the French Neuropathic Pain Group to screen for neuropathic pain.MethodsThis prospective observational study was undertaken in three hospitals to assess the validity of a Japanese translation of the DN4. We first translated the DN4 into Japanese using a forward–backward method. Pain specialists then examined patients independently and diagnosed them with neuropathic or non-neuropathic pain, according to the International Association for the Study of Pain definitions. The Japanese version of the DN4 questionnaire was then given to each patient.ResultsOf 187 patients that met our inclusion criteria, 100 and 87 were diagnosed with neuropathic and non-neuropathic pain, respectively. The test–retest intra-class correlation coefficient (95% confidence interval) was 0.827 (0.769–0.870). Among patients with identical diagnoses of neuropathic or non-neuropathic pain, receiver-operating characteristic curve analysis revealed an area under the curve of 0.89. A cut-off point of equal or greater than 4 resulted in a sensitivity of 71% and specificity of 92%.ConclusionThe Japanese version of the DN4 was found to be a helpful tool for discriminating between neuropathic and non-neuropathic pain.

A Case of Anaphylactic Shock Diagnosed on Second Implementation of Anesthetic Management

著者連絡先 松木悠佳 〒 910-1193 福井県吉田郡永平寺町松岡下合月 23-3 福井大学学術研究院医学系部門医学領域 器官制御医学講座麻酔・蘇生学 タニルで麻酔を導入し,ロクロニウム投与後に気管 挿管した.挿管後に血圧が36/26mmHgに低下し, エフェドリン,フェニレフリン,ノルアドレナリン の投与を行ったが反応は乏しかった.皮膚の発赤や 気道内圧上昇は見られなかった.心エコーで,左心 室壁運動や弁に異常はないが心腔容積の減少を認め たため循環血液量減少と判断した.急速輸液と塩酸 ドパミン持続投与で血圧は徐々に上昇した.術中ロ クロニウムの追加投与は必要としなかった. 2カ月後に,くも膜下出血後の水頭症に対し脳室腹腔シャント術(VPシャント術)を予定した.1回 目と同様に麻酔導入し気管挿管した.血圧が35/ 27mmHgに低下したため,エフェドリンを投与し たが血圧は上昇しなかった.全身の発赤に気づきア ナフィラキシーを疑い,アドレナリン,メチルプレ ドニゾロンを静脈内投与し,手術は中止した.同時 はじめに

A successfully treated case of cardiac arrest after Caesarean section complicated by pheochromocytoma crisis and amniotic fluid embolism

Both pheochromocytoma and amniotic fluid embolism (AFE) are important causes of maternal mortality. We present a case of a 29-year-old woman who developed cardiac arrest after Caesarean section, complicated by both pheochromocytoma crisis and AFE. After resuscitation, the patient developed multiple organ dysfunction, rhabdomyolysis and disseminated intravascular coagulation (DIC). After institution of multidisciplinary interventions (including the use of an intra-aortic balloon pump, extracorporeal membrane oxygenation, continuous hemodiafiltration, and neuroprotective therapeutic hypothermia) the patient made a full recovery without any apparent neurological deficit.

Formation of a fibrin net on the polypropylene membrane oxygenator used for percutaneous cardiopulmonary support in a patient with acute myocarditis

To the Editor: A polypropylene membrane oxygenator is commonly used for extracorporeal membrane oxygenation, although its limitations include the development of plasma leakage and the wet lung phenomenon [1,2]. An additional limitation is fibrin net formation with blood cells over the oxygenator membrane, as demonstrated by electron microscopy. The fibrin net formation occurred in a patient with acute myocarditis. A 29 year old man was diagnosed with acute myocarditis, then intubated and ventilated in the intensive care unit. An intra-aortic balloon pump was inserted, and percutaneous cardiopulmonary support (PCPS; CAPiox EBS; Terumo Corp., Tokyo, Japan) was initiated with a polypropylene membrane oxygenator (Capiox SX18; Terumo Corp.) to maintain his circulation and blood oxygenation. Heparin 15,000 U/day was administered to adjust activated clotting time (ACT) to over 200 seconds. Since PaO2 at the outflow from the membrane oxygenator was 75 mmHg, with an FIO2 of 1.0 20 hours after the start of PCPS, the membrane oxygenator was replaced with a new one of the same type. However, 10 hours after the replacement, PaO2 decreased once more. Thereafter, frequent replacement of the oxygenator was needed at about 10-hour intervals over the next two days. Arterial oxygen concentration at the outflow of the oxygenator increased immediately after each replacement, but gradually decreased thereafter. As there were visible milky white agglomerates in the inflow and outflow ports of the non-functioning polypropylene membrane oxygenator (Fig. 1), the oxygenator manufacturer investigated the cause of the poor oxygenation. The manufacturer noted the following findings: There was no damage to the membrane and fiber bundle. During 20 L/min air supply into the oxygenator via the inflow path, no outflow of plasma at the outflow path was observed. After fixation of the membrane with glutaraldehyde solution, a fibrin net with blood cells was

Cluster headache with Brugada electrocardiogram pattern: a case report

Agents including the effect on sodium channel are restricted in patients with Brugada electrocardiogram (ECG) pattern or Brugada syndrome. On the other hand, many therapeutic agents for cluster headache (CH) block sodium channel. After recommended therapies without sodium channel blocking effect were failed in a 40-year-old male with CH whose ECG shows Brugada ECG pattern, clonazepam and codein phosphate, which are exceptional treatments for CH, were effective for severe unilateral orbital pain.