Effects of Norepinephrine on Left Ventricular Hemodynamics and Myocardial Blood Flow in Rats with and without Calcium Overload

Heart failure patients have been shown to have an increased blood norepinephrine concentration, and patients with a high norepinephrine concentration have a poor prognosis. Norepinephrine is a catecholamine with α_1 and β_1 effects, which lead to a vasoconstrictive action and enhancement of myocardial contraction. However, the consequences of norepinephrine-induced changes in myocardial blood flow in heart failure patients remain unknown. In this study, the influence of norepinephrine on hemodynamics and blood flow in the left ventricular myocardium was investigated using rats with and without a calcium load. Norepineph-rine without a calcium load induced a 29.3% reduction of myocardial blood flow (MBF), but had no significant effect on ejection fraction (EF) and left ventricular end-diastolic pressure (LVEDP). With simultaneous calcium administration, norepinephrine induced a 33.2% reduction of MBF and increased LVEDP significantly, but caused no reduction in EF. These results suggest that norepinephrine decreases MBF but has no effects on systolic function, and increases LVEDP and decreases MBF more markedly in combination with calcium

ラット ニオケル カルシウム フカカ ノ ノルエピネフリン ニヨル キュウセイ サシツ カクチョウ ショウガイ : サシツ ケッコウ ドウタイ ナラビニ シンゾウ チョウオンパホウ ニヨル ケントウ

拡張不全は左室収縮の低下を伴わない心不全で,左室収縮の低下による収縮不全とは病態,基礎疾患,予後が異なることが明らかにされつつある.しかし,その発生メカニズムについては十分に解明されていない.本研究では雄性ラット42匹を用い,対照群,塩化カルシウム投与群,ノルエピネフリン投与群,塩化カルシウム投与後,塩化カルシウム+ノルエピネフリン投与群において,左室血行動態,左室拡張障害について検討をおこなった.4群でチップ付き圧カテーテルを左室内へ挿入し,また別の4群で心臓超音波法により左室駆出率を測定した.さらに別に拡張早期急速流人期血流速波形(E波),拡張後期流人速波形(A波),E波減速時間(DCT),組織ドプラ法で拡張早期僧帽弁輪速度(Ea波)を測定した.その結果,塩化カルシウム群,ノルエピネフリン群では左室拡張末期圧は変化を認めなかったが,塩化カルシウム+ノルエピネフリン投与群で左室拡張末期圧は著しい上昇を認めた.また,塩化カルシウム+ノルエピネフリン群では左室駆出率は対照群と有意差を認めなかったが,E波,DCT,Ea波は対照群に比し有意な減少を認めた.以上より,塩化カルシウム負荷下でのノルエピネフリン投与で急激な心臓拡張障害が惹起され,心臓の拡張障害の発生にノルエピネフリンが関与している可能性が示唆された.In diastolic dysfunction, cardiac cells in the diastolic phase do not rapidly or completely return to the normal state of relaxation. However, the detailed mechanism remains unknown. To develop an acute diastolic dysfunction model in the rat, norepinephrine (30μg/kg/min) with calcium (12mg/kg/min) was administered for 20 minutes, following 20-minute administration of calcium, compared with the control group. A cardiovascular mikro-tip pressure transducer catheter was inserted into the left ventricle, and the intraventricular pressure and left ventricular end-diastolic pressure were determined. Early diastolic mitral annular velocity (Ea), E and A waves, deceleration time (DCT) and left ventricular ejection fraction were estimated using tissue Doppler imaging and echocardiography. In the norepinephrine with calcium group, no significant change in left ventricular pressure was found, but left ventricular end-diastolic pressure was markedly increased. On echocardiography, no change was found in left ventricular ejection fraction, but the E wave, DCT and Ea wave were decreased, in comparison with the control, calcium alone and norepinephrine alone groups. The results of this study could indicate that norepinephrine administration with calcium causes acute diastolic dysfunction in the rat

Simulation des écoulements diphasiques dans les stations de pompage

The purpose of the present study is to develop numerical tools for two-phase flow ploblems in pumping stations. Reliable simulation methods of two-phase flow are inevitable in nuclear engineering field because computer programs are important design tools for nuclear reactors which are exposed to severe ambient conditions of high temperature, high pressure and gamma ray irradiation. Mock-up tests of nuclear thermal-hydraulics are very difficult. Hitachi Ltd. has created advanced computer programs for multi-dimensional two-phase flow to analize reactor systems and components. The numerical methods enable accurate and stable interface calculation in spite of large density ratio between the phases, because non-staggered finite volume method, which is suitable for treatment of discontinuity, and minimum numerical diffusion are adopted. The multi-dimensional computer programs employ two types of two-phase flow model. The first one is the extended two-fluid model, which has capability of both interface tracking and ordinary two-fluid model calculations. This model is appropriate for the present purpose because it can treat free surface of channels and entrained bubbly mixture due to breaking waves. The second one is the improved VOF (Volume of Fluid) method in which PLIC (Piecewise Linear Interface Calculation) technique was employed. The interface state calculation is simplified by approximating cubic calculation cells to spherical ones. These computer program were applied to hydraulic studies in Hitachi Industries Co., Ltd., a vender of fluid machinery and pumping systems. It is necessary to evacuate air downstream from siphon outlets as bubble entrainment by water flow in order to operate the plant effectively after pumping station start-up. Experiments were carried out by using a reduced scale test-section. The test section was made of transparent acryl and the cross-section was rectangular. Free surface of water layer on the inclined wall and entrained bubbly mixture into the water pool due to water layer collision with free surface were observed by a video camera. The extended two-fluid model results of transient water level and pressures in the simulated siphon outlets were in good agreement with the experimental data. The predicted pressure histories at the crest and the pump site were in good agreement with the experimental data. The sedimentation in a inlet channel of a pump station was carried out. Three dimensional free surface flow was calculated by the improved VOF method and behavior of suspended sediment in the flow field is calculated. The surface wave velocity in the shallow channel was in good agreement with the theoretical one. Sediment particles had size distribution and drag force and gravity and buoyancy was taken into consideration. Critical tractive force of the sediment on floor was estimated from Schields’ correlation. The predictions of sedimentation area and suspended fraction agreed well with experimental data. These results showed that the present computer programs were able to treat key two-phase flow phenomena in pumping stations

Signet-Ring Cutaneous Squamous Cell Carcinoma Arising on the Back of the Finger

A variety of pathologic variants of cutaneous squamous cell carcinoma (SCC) has been reported, and the signet-ring variant of cutaneous SCC is extremely uncommon. We reported an 83-year-old man with signet-ring SCC arising on the back of the finger. As far as we know, only 4 cases have been described in detail, and one dermatopathologic report focused on the presence of signet-ring cells briefly described in clinical data of 6 cases. Interestingly, in these reports, the skin lesions of 10 cases occurred exclusively in the head and neck area. This case involved a skin lesion on the back of the finger and is thus the first reported case of signet-cell cutaneous SCC that did not arise in the head and neck area. The location of this lesion, together with the histological findings compatible with actinic keratosis, support the hypothesis that the development of signet-ring SCC is related to ultraviolet light-induced damage

Successful Treatment of Mediastinal Unicentric Castleman’s Disease Using Video-Assisted Thoracoscopic Surgery with Preoperative Embolization

Unicentric Castleman’s disease is a rare, benign lymphoproliferative disorder that is curable with surgical resection. However, significant bleeding often occurs during surgery because of tumor hypervascularity. We herein present a case of hyaline-vascular-type mediastinal unicentric Castleman’s disease, successfully resected using video-assisted thoracoscopic surgery with preoperative embolization. In the present case, tumor hypervascularity and feeding vessels were revealed by computed tomography (CT), which led us to perform preoperative angiography and embolization to the tumor feeding arteries to reduce intraoperative bleeding. Castleman’s disease should be considered in the differential diagnosis of hypervascular mediastinal tumors. Tumor vascularity should be assessed prior to surgery, and preoperative embolization should be considered

Chronic Diarrhea as the Presenting Feature of Amyloidosis with Multiple Myeloma: A Case Report Diagnosed by a Myocardial Biopsy

A 73-year-old woman with a history of diarrhea for one year and other various symptoms was admitted to our hospital. Gastrointestinal endoscopy that included enteroscopy with multiple biopsies was performed. However, no significant findings were observed. Electrocardiography showed low voltage in all limb leads, and an echocardiogram showed thickened cardiac walls with granular sparkling pattern. A myocardial biopsy revealed amyloidosis, and a bone marrow biopsy showed multiple myeloma. This case suggests that we should suspect the possibility of amyloidosis in a patient with diarrhea and various symptoms involving multiple organ systems. Additionally, electrocardiograms and echocardiograms should be performed even when gastrointestinal biopsies reveal negative results