An Analysis of Cardiopulmonary Hemodynamics During Hemorrhagic Shock in Dogs

Utilizing the standard Wiggers' method, hemorrhagic shock was induced in ten anesthetized dogs by bleeding to a mean arterial pressure (MAP) of 50 mmHg for 2 hr and then to 30 mmHg for 1 hr, followed by reinfusion of the shed blood. The experimental protocol was designed to evaluate the effect of hemorrhagic shock on sequential pulmonary hemodynamic changes in relation to those of cardiac and systemic circulation. All selected cardiopulmonary hemodynamic parameters were recorded throughout the experiment on a multi-channel poly-oscillograph monitor. Total pulmonary resistance (TPuR) started rising early in hemorrhagic shock and was found to rise to a level that was 10-fold greater than pulmonary arteriolar resistance (PAR). This meant that, 90% of TPuR came from the venous side of the pulmonary vascular bed. Persistently raised TPuR even after reinfusion was linked to early death of the experimental animals. Myocardial contractility (max dp/dt mmHg/sec) which is one of the indices for cardiac performance was found to be severely depressed at terminal stage (p<0.001). Both total pulmonary and peripheral resistances were found to have an inverse relationship to ventricular performance which was measured by left ventricular stroke work (LVSW) and right ventricular stroke work (RVSW). There is a high suspicion that reinfusion or resuscitation following prolonged hypovolemic shock may aggrevate the hemorrhagic shock effects by facilitating the distribution of accumulated blood-borne toxic substances to various target organs and that, this has been linked with the early and sustained pulmonary hemodynamic disturbance found in these experiments

Blood Sugar in Relation to Endocrine Hormones During Hemorrhagic Shock in Dogs

Wiggers' standard method was used to induce hemorrhagic shock in eighteen anesthetized dogs by bleeding to a mean arterial pressure (MAP) of 50 mmHg for 2 hr and then to 30 mmHg for 1 hr, followed by reinfusion of the shed blood. The experimental protocol was designed to determine the sequence of changes in blood sugar during hemorrhagic shock and its relationship to variations in the underlying endocrine hormones, in particular the levels of insulin, catecholamines and cortisol. Venous blood samples were drawn from all experimental animals at specific regular time intervals for sugar and endocrine hormones determination. In early stages of hemorrhagic shock, blood sugar, catecholamines and cortisol were shown to be raised while insulin levels were not influenced by fluctuations in sugar levels. This suggested that, the effect of catecholamine inhibition on the synthesis of insulin is greater than the blood sugar stimulus on the secretion of insulin. Moreover pancreatic islet cells were shown to be intact at terminal stage by Electron microscopy. Corresponding elevated blood levels of sugar, catecholamines and cortisol were found to have a common goal towards increasing plasma osmolality to effect plasma refill. Persistent hypoglycemia in late stages of hemorrhagic shock was shown to be a major sign of failing neuroendocrine compensatory mechanisms against a shock insult. Electron microscopy revealed severe damage of the pituitary gland at the terminal stage

Three-Dimensional Vascular Architecture of the Dog Heart as Revealed by Injection Replica Scanning Electron Microscopy

The three-dimensional vascular architecture of the dog myocardium was investigated by means of injection replica scanning electron microscopy. Coronary arteries entered into myocardial wall at almost right angle. They repeated bicornal divisions and run toward endocardium. The arterioles and precapillary arterioles branched in bicornal, tricornal or multicornal fashions. These branches were arranged usually in a plane in short distances. Capillaries were arranged parallel to the myocardial cells and had many anastomotic channels. The branching of the capillaries was usually Y-, T-, H- or K-shape, and Y-shape was the most common. Many anastomotic channels between precapillary arterioles were recognized just under the endocardiurn, while same connections were very difficult to identify in the myocardial wall. Numerous venous capillaries joined together with postcapillary venules and collecting venules almost exclusively in a plane parallel to the capillary sheets. Junctional architecture of these capillaries and venules was usually fan-shaped, finger-shaped or feather-shaped in appearance. The postcapillary venules and collecting venules were oriented usually perpendicular to the muscle fiber or capillary direction. The orifices of Thebesian veins, arterio-luminal vessels and arterio-sinusoidal vessels were observed between ventricular trabeculae as small masses of injected resin. The number of these orifices were more abundant in the right ventricular wall than in the left

Experimental Evaluation of Bretschneider's Solution for Myocardial Preservation in Cardiac Transplantation

Myocardial preservation by Bretschneider's solution (BR solution, Group I) with an intracellular like electrolyte and histidine buffer action was compared with EC-Bi solution (Group II) which has an extracellular like electrolyte and bicarbonate buffer action in the mongrel dogs. The PH and PCO2 of the effluent from the coronary sinus were maintained during myocardial ischemia for 3 hr but the lactate rose gradually in group I. The oxygen and lactate up-take ratio of the myocardium after re-perfusion was satisfactory and LV max dp/dt was also maintained at a high level in group I. Morphologically, myelin figure and mitochondrial deformation were more found in group II on electron microscopy. A donor heart preserved for 3 hr in cold BR solution was transplanted in the left thoracic cavity in four mongrel dogs by the technique of the heterotopic cardiac transplantation. Resuscitation of cardiac pulsation was smooth and maintenance of the systemic circulation after transplantation was possible in every case. From these findings, it might be concluded that myocardial preservation using cold BR solution was useful for cardiac transplantation

Effect of Immunomodulatory Artificial Blood Exchange (IABX) on Guinea Pig-to-Rat Heart Xenografts

The aim of this study was to assess the effectiveness of pregraft immunomodulatory artificial blood exchange (IABX) in a guinea pig-to-rat xeno discordant heart transplantation, using an artificial blood (FC43 emulsion: The Green Cross, Japan) in exchange for a large volume of whole blood to remove humoral immune factors en bloc from the recipient rat. In the rats treated with IABX, rhythmic beating of the grafted heart was maintained for 2 hr, whereas the untreated heart beat lasted for only 15.2 ± 5.2 min (n=6). In the graft hearts treated with IABX, no pathologic changes such as multiple coronary thromboses due to hyperacute rejection (HAR) were observed. Humoral immune factors (natural-IgM titer, ACH50 and CH50 complement activities, platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen serum concentration), which are thought to contribute to HAR, decreased significantly following the IABX treatment.　　 We conclude that IABX is an efficient method for prolonging the survival time of guinea pig heart xenografts by inhibiting thrombus formation in the xeno-graft heart. It was confirmed that IABX could remove recipient humoral immune factors en bloc.This study was supported by The Green Cross Co.,Ltd

The role of astrocytes during repair of cerebral infarction in mdx mice

様々な大きさのジストロフィンアイソフォーム(427kDa, 260kDa, 140kDa, 116kDa, 71-75kDa)が広く体内に存在していることはよく知られている.中枢神経系においては71-75kDaのDp71が著明に多く,毛細血管の内皮の基底膜に接しているアストロサイトの細胞質に局在することが報告されている.しかしながらDp71の機能についてはよくわかっていないことが多い.そこで今回,脳組織におけるDp71の役割を調べるために,コントロールマウス(wild-typeマウス)およびデュシャンヌ型筋ジストロフィーモデル動物であるmdxマウスを用いて実験的脳梗塞を作成し,その治癒過程を形態学的に観察した.また,GFAPおよびDp71に関して生化学的に分析をおこなった.HE染色およびGFAP免疫組織学的染色の結果から,形態学的にはmdxマウスとコントロールマウスの脳に違いは認められなかった.しかしながら,mdxマウスの脳において,Dp71の発現量がコントロールマウスよりも少ないことがわかった.またmdxマウスにおいて,脳梗塞の修復過程におけるアストロサイトの反応がコントロールマウスよりも弱いことがわかった.これらの結果から,mdxマウスの脳において,アストロサイトの機能,アストロサイトの血管新生に関わる機能の障害されていることが示唆された.It is now well known that dystrophin isoforms (427kDa, 260kDa, 140kDa, 116kDa, 71-75kDa) are widely distributed throughout our body. In the central nervous system a considerable amount of Dp71 (71-75kDa) is found in the perivascular cytoplasm of the astrocytes. However, the function of this dystrophin is still unknown. To investigate the role of Dp71 in the brain tissue, cerebral infarction was induced in the control (wide-type) mouse and mdx mouse which is known as an animal model of human muscle dystrophy (Duchenne type), and morphological changes of the infarcted area were observed during repair of the infarction. In addition, biochemical analysis of GFAP and Dp71 was carried out in the brain of the control and mdx mouse. In our present study, there were no differences in brain morphology between mdx and control mouse as revealed in H-E stain and GFAP immunohistochemistry. However, the Dp71 were smaller in quantity in the brain of the mdx mouse than that of the control mouse. The reaction of astrocytes during repair of serebral infarction was distinctly delayed in the mdx mouse compared with that of the control mouse. These findings suggest that the astrocytes in the brain of the mdx mouse are functionally impaired including perivascular cytoplasmic processes with relation to neo-vascularization

Expression of myogenin, MyoD and MHC isoforms in regenerating skeletal muscle.

骨格筋再生過程におけるミオシン重鎖(MHC)アイソフォーム発現とmyogenin，MyoDタンパクの発現様式との関連性を検討するために，塩酸ブピバカインを用いてマウスヒラメ筋損傷モデルを作成し，損傷筋の再生過程を組織形態学的に確認すると同時に，再生各段階におけるMHCアイソフォームと，myogeninおよびMyoDタンパク発現を経時的に検索した．本研究における筋損傷は塩酸ブピバカインをマウス(C57BL/10SnSlc)のヒラメ筋に注入することで作成した．組織学的には，塩酸ブピバカイン投与後3日目で筋線維はほとんど消失し，処置後6日目で中心核を有する再生筋線維がかなり出現し，処置後28日目では対照群のものと同程度まで回復した．生化学的分析では，対照群ヒラメ筋はMHCⅠ(34．3±1．7%)とMHCⅡa(65．7±1．7%)で構成されていた．実験群ヒラメ筋ではMHCⅠは処置後14日目まで減少し，その後増加傾向を示し，処置後90日目では36．3±2．9%となった．また，正常ヒラメ筋では検出されない速筋型MHC(MHC Ⅱd，MHC Ⅱb)が処置後3日目から28日目まで検出された．Western blotを用いた分析では，myogeninタンパク正常ヒラメ筋（遅筋）で検出された一方，前脛骨筋（速筋）においては検出できなかった．実験群ヒラメ筋では，myogeninは対照群と比較して処置後３日目より増加し（3．1±0．5），処置後６日目でピークに達した（5．8±0．8）．それからmyogeninタンパクは徐々に減少していったが，処置後90日目においてもなお対照群ヒラメ筋の1．8倍の発現を維持し続けた．一方，MyoDタンパクは正常前脛骨筋において正常ヒラメ筋の3．3倍の発現が認められた．MyoDは処置後３日目で対照群ヒラメ筋と比較して5．4倍になりピークに達した．その後は徐々に減少し始めた．しかし処置後90日目においても2．2倍の発現があった．これらのことから筋の再生過程においては速筋タイプの筋細胞が出現するmyogeninとMyoDは衛星細胞の分化と筋の再生に密接に関係していることが示唆された．To investigate the precise mechanism of skeletal muscle cell regeneration, the changing pattern ofmyosin heavy chain(MHC)isoforms during the regenerating process was observed with relation to theactivation of myogenin and MyoD. In addition, histopathological observation of the damaged muscles wasperformed throughout the experiment.In this study, muscle damage was induced by intramuscular injection of bupivacaine hydrochloride in thesoleus muscle of mice (C57BL/10SnSc). In the light microscopic observation, muscle cells had almost disappeared at 3 days after bupivacainetreatment with severe inflammatory cell infiltration. At 6 days after treatment, a considerable number ofregenerating muscle cells containing centrally located nuclei appeared in the damaged soleus muscle. At28 days, these regenerating muscle cells showed almost the same appearance as the control muscle cellscontaining subsarcolemmal nuclei, although a small number of muscle cells with central nuclei were stillrecognized.In the biochemical analysis, control soleus muscles contained only MHC I (34.3±1.7 %)and MHC IIa(65.7±1.7 %). In the damaged muscles, MHC I was decreased toward 14 days after treatment, and thengradually increased. At 90 days, the contents of MHC I was finally recovered to 36.3±2.9 %.0 In addition,MHC IId and MHC IIb appeared in the damaged muscle from 3 to 28 days after treatment. However, theyhad disappeared at 90 days.Using western blot analysis, myogenin protein was recognized in the control soleus muscles (slow typemuscle), while the myogenin could not be found in the first type muscle of the anterior tibial muscle. Themyogenin contents increased to about three fold (3.1±0.5)at 3 days after treatment compared withthose of control muscles and reached the maximum level (5.8±0.8)at 6 days after treatment. Then, myogenin contents gradually decreased,although they still remained high (1.8 times)at the end of experiment (90 days after treatment). Incontrast to the myogenin protein, a high level (3.3 times)of MyoD protein was detected in the anteriortibial muscle compared with that of control soleus muscles. In the damaged soleus muscles, MyoDcontents reached a maximum level (5.4 times)at 3 days after treatment compared with that of controlsoleus muscles, and then gradually decreased toward the end of experiment. However, MyoD protein stillremained 2.2 times compared with that of control soleus muscles. These findings described above indicate that, 1)a property of fast type muscle cells appeared in theregenerating muscle cells during the regenerating process, and 2)myogenin and MyoD are closelyrelated to the differentiation of the satellite cells and regeneration of the skeletal muscle cells

Function of skeletal muscle sarcoplasmic reticulum and expression of sarcoplasmic reticulum Ca2+-ATPase in right congestive heart failure rats

右心不全に伴って,速筋および遅筋の筋小胞体Ca2+取り込み能が減少するという仮説を検証した.右心不全は,モノクロタリン(30 ㎎/㎏)を投与することにより引き起こし,投与後4週で,長指伸筋およびヒラメ筋を両後肢から採取した.筋の疲労耐性は,連続的な強縮刺激を行うことにより測定した.長指伸筋では刺激開始1分後,ヒラメ筋では4分後の張力を測定し,初期値に対するそれらの割合を疲労の指標とした.長指伸筋およびヒラメ筋の疲労耐性は,右心不全群で有意に低下した.筋小胞体Ca2+取り込み速度は,Indo-Ⅰを付加したホモジネートで測定した.その結果,Ca2+取り込み速度は,長指伸筋で25.4%(p<0.01),ヒラメ筋で30.4%(p<0.05)低下した.このCa2+取り込み速度の低下は,筋小胞体Ca2+-ATPaseタンパク量の低下と一致した.筋小胞体Ca2+取り込み能の低下は,筋張力の低下を引き起こし,このCa2+ handlingの低下は,少なくとも右心不全による運動耐容能の低下の一因であろう.In this study, we investigated the hypothesis that right congestive heart failure (CHF) would impair sarcoplasmic reticulum (SR) Ca2+ uptake in skeletal fast- and slow-twitch muscles. To induce CHF, the rats were injected with monocrotalin (30 ㎎/㎏). After 4 weeks of injection, extensor digitorum longus (EDL) and soleus (SOL) muscles were sampled from both hind limbs. Muscle fatigue resistance was measured in vitro as the relative decline in force production of tetanic contraction induced by electrical stimulation over 1 and 4 min in EDL and SOL, respectively. Evaluation of fatigue characteristics showed that CHF significantly reduced fatigue resistance in both muscles under study.SR Ca2+uptake rate wasmeasured in vitro with Indo-I on muscle homogenates. As hypothesized, Ca2+uptake rate was decreasedby 25.4%(P < 0.01) and 30.4%(P < 0.05) in EDL and SOL, respectively. This decline in Ca22+uptake ratewas accompanied by an immunochemically determined decrease in SR Ca2+-ATPase protein. Taking intoaccount previous findings that the depressed SR Ca2+uptake leads to the reduce in muscle forceproduction, these results suggest that impaired SR Ca2+handling capacity in skeletal muscle may accountat least partly for deteriorations in exercise tolerance resulting from right CHF

Characterization of H5N1 highly pathogenic avian influenza virus strains isolated from migratory waterfowl in Mongolia on the way back from the southern Asia to their northern territory

AbstractH5N1 highly pathogenic avian influenza (HPAI) viruses were isolated from dead wild waterfowl at Khunt, Erkhel, Doityn Tsagaan, Doroo, and Ganga Lakes in Mongolia in July 2005, May 2006, May 2009, July 2009, and May 2010, respectively. The isolates in 2005 and 2006 were classified into genetic clade 2.2, and those in 2009 and 2010 into clade 2.3.2. A/whooper swan/Mongolia/6/2009 (H5N1) experimentally infected ducks and replicated systemically with higher mortality than that of the isolates in 2005 and 2006. Intensive surveillance of avian influenza in migratory waterfowl flying from their nesting lakes in Siberia to Mongolia in every autumn indicate that HPAI viruses have not perpetuated at their nesting lakes until 2009. The present results demonstrate that wild waterfowl were sporadically infected with H5N1 HPAI viruses prevailing in domestic poultry in the southern Asia and died in Mongolia on the way back to their northern territory in spring