松本 浩毅

We describe a primary malignant mesenchymal tumor of the heart in an 8-year-old miniature Schnauzer that was euthanatized because of poor prognosis. At necropsy, multiple milky-white masses of various sizes were seen to project from the endocardium into the right atrial and both ventricular cavities. On histopathological examination, the cardiac neoplasia was diagnosed as primary malignant peripheral nerve sheath tumor. There have been no previous reports of such a tumor occurring in the canine heart.

Fatty acids are a major source of energy in the normal myocardium and are taken up passively from the bloodstream. However, with heart failure, the use of fatty acids decreases in the myocardium. Therefore, serum fatty acid concentrations in dogs with mitral insufficiency (MI) might differ from those in normal dogs. The present study was designed to determine the serum fatty acid compositions in dogs with different severities of MI according to the classification proposed by the International Small Animal Cardiac Heart Council (ISACHC) and to elucidate the relationships between the determined compositions and echocardiographic parameters. In total, 30 dogs with MI were divided into 3 groups (I, II, and III) according to the ISACHC classification of MI severity. The healthy group consisted of 12 dogs matched with the MI groups for age and body weight. The serum concentrations of 13 fatty acids were measured by gas chromatography. The levels of linoleic acid (LA), docosatetraenoic acid (DTA), and arachidonic acid (AA) in group I were significantly lower than those in the healthy group (p<0.05). The levels of eicosapentaenoic acid (EPA) and AA in group II were significantly lower than those in the healthy group (p<0.05). The level of EPA in group III was significantly lower than that in the healthy group (p<0.05). In addition, the ratio of EPA to AA levels (EPA/AA ratio) in group III was significantly lower than that in the healthy group (p<0.05). With regard to the relationships between fatty acid concentrations in all MI groups (I through III) and echocardiographic parameters, the levels of AA and DTA showed a significant positive correlation with the ratio of left ventricular end-diastolic internal diameter to aortic diameter (LVIDd/Ao ratio) (AA, r=0.396 and p=0.048; DTA, r=0.426 and p=0.027). In addition, the docosapentaenoic acid (DPA) level correlated negatively with fractional shortening (r=-0.437 and p=0.023). Furthermore, the EPA/AA ratio correlated negatively with the ratio of left atrial to aortic diameters (r=-0.383 and p=0.048). The fatty acid concentrations and ratios in the dogs with 3 types of MI according to the ISACHC classification differed from those in healthy dogs. Some of these concentrations and ratios correlated with echocardiographic parameters.

Cushing's disease caused by pituitary corticotroph adenoma is a common endocrine disease in dogs. A characteristic biochemical feature of corticotroph adenomas is their relative resistance to suppressive negative feedback by glucocorticoids. The abnormal expression of 11beta-hydroxysteroid dehydrogenase (11HSD), which is a cortisol metabolic enzyme, is found in human and murine corticotroph adenomas. Our recent studies demonstrated that canine corticotroph adenomas also have abnormal expression of 11HSD. 11HSD has two isoforms in dogs, 11HSD type1 (HSD11B1), which converts cortisone into active cortisol, and 11HSD type2 (HSD11B2), which converts cortisol into inactive cortisone. It has been suggested that glucocorticoid resistance in corticotroph tumors is related to the overexpression of HSD11B2. Therefore it was our aim to investigate the effects of carbenoxolone (CBX), an 11HSD inhibitor, on the healthy dog's pituitary-adrenal axis. Dogs were administered 50 mg/kg of CBX twice each day for 15 days. During CBX administration, no adverse effects were observed in any dogs. The plasma adrenocorticotropic hormone (ACTH), and serum cortisol and cortisone concentrations were significantly lower at day 7 and 15 following corticotropin releasing hormone stimulation. After completion of CBX administration, the HSD11B1 mRNA expression was higher, and HSD11B2 mRNA expression was significantly lower in the pituitaries. Moreover, proopiomelanocortin mRNA expression was lower, and the ratio of ACTH-positive cells in the anterior pituitary was also significantly lower after CBX treatment. In adrenal glands treated with CBX, HSD11B1 and HSD11B2 mRNA expression were both lower compared to normal canine adrenal glands. The results of this study suggested that CBX inhibits ACTH secretion from pituitary due to altered 11HSD expressions, and is potentially useful for the treatment of canine Cushing's disease.

本研究における慢性圧負荷モデル犬では、2D-STE法で評価した心筋運動のうち、長軸方向の心筋機能が最も早期に影響を受けた。今後、長軸方向心筋機能は圧負荷病態の早期検出に有用となるかもしれない。この長軸方向心筋機能の臨床的有用性や予後評価への有用性に関してはさらなる検討が必要である。(著者抄録)

本研究ではMMVDに続発したPHの犬における左室機能指標を検討した。MMVDでは軽度な病態でもPHを併発する症例が存在し、さらにMMVDにPHの影響が加わることで左室機能も影響を受け、PH併発症例における心不全臨床徴候に寄与している可能性が考えられた。(著者抄録)

Background Systolic dysfunction is associated with poor outcomes in dogs with myxomatous mitral valve disease. However, assessment of systolic variables by conventional echocardiographic methods is difficult in these dogs because of mitral regurgitation (MR). Hypothesis We hypothesized that assessment of systolic function by dobutamine stress may identify systolic dysfunction in dogs with MR, and that 2-dimensional speckle-tracking echocardiography (2D-STE) could quantitatively evaluate myocardial function. Animals Anesthetized dogs with experimentally induced MR. Methods Dogs were examined for systolic myocardial deformations using 2D-STE during dobutamine infusion before and 3 and 6months after MR induction. We evaluated peak systolic rotation and rotation rate in each basal and apical view; peak systolic torsion and torsion rate were also calculated. Results Invasive peak positive first derivatives of left ventricular pressure (dp/dt) were significantly decreased in dogs 6months after induction of MR compared with pre-MR results. After 3 and 6months of MR, dogs had diminished peak systolic torsion values and torsion rates in response to dobutamine infusion compared with pre-MR results (3months, PP=.006; 6months, P=.003 and P=.021). These results were significantly correlated with overall invasive dp/dt (r=0.644, Pr=0.696, P&lt;.001). Conclusions and Clinical Importance Decreased torsion during dobutamine infusion in dogs with MR may reflect latent systolic dysfunction. Dobutamine infusion, therefore, may be useful for the assessment of systolic function in dogs with MR.

元気消失の主訴でホルスタイン種雌育成牛（121日齢）を診察したところ，発熱，膿尿および触診で右腎臓腫脹が認められた．超音波診断検査で腎盂の拡張と内容物の貯留が認められた．化膿性腎盂腎炎を疑い抗生剤で加療したが効果はみられず，一般症状が悪化し，内科的治療では治癒不能と思われた．血液検査で尿素窒素およびクレアチニン値は正常であり，左腎臓機能には異常がないと思われたため，生後149日齢に右腎臓を全摘出した．摘出した右腎臓は重さ6.48㎏で，腎盂は拡張してチーズ様膿が充満していた．腎臓摘出後は順調であり，79カ月齢で腰痿によって死亡するまで，腎臓機能，体重，繁殖成績，病歴および泌乳量を経過観察したところ，いずれも明瞭な異常は認められず，育成期の右腎臓摘出はその後の乳牛の能力に悪影響を与えないことが示唆された．

Objectives: The objective of this study was to evaluate the effect of age on myocardial function assessed by two-dimensional speckle-tracking echocardiography (2D-STE) in healthy dogs. Animals: Thirty-two healthy Beagles were used. Methods: Myocardial function was assessed in each dog by using 2D-STE, and the results were compared between young and old dogs. Results: The myocardial deformations in systole, besides the apical rotation rate, were not significantly different between young and old dogs. In contrast, the early diastolic circumferential strain rate, basal rotation rate, and torsion rate were significantly lower in old dogs than in young dogs (P = 0.03, P = 0.033, and P = 0.015, respectively). Late diastolic longitudinal and radial strain rates were significantly higher in old dogs than in young dogs (P = 0.002 and P = 0.018, respectively). Conclusions: Young and old dogs showed similar systolic myocardial deformations, but significant differences in the values of some diastolic deformation variables were found between young and old dogs, highlighting the need for using age-matched control subjects in studies of diastolic function. (C) 2013 Elsevier B.V. All rights reserved.

A 25-month-old Chihuahua dog with no clinical signs was evaluated for high serum liver enzymes. Ultrasonography and computed tomography revealed a mass in the left hepatic medial lobe. The histological diagnosis reached using resected tissues was hepatocellular carcinoma (HCC). To the authors' knowledge, this is the youngest dog diagnosed with HCC.

Objective: The objective of this study was to evaluate the influence of heart rate (HR) on myocardial function assessed by two-dimensional speckle-tracking echocardiography (2D-STE) in healthy dogs. Animals: Thirteen healthy beagle dogs. Methods: Animals were anesthetized and HR was controlled with right atrial pacing. Myocardial function of each dog was assessed using 2D-STE at pacing rates of 120, 140, 160, and 180 bpm. Results: All strain and strain rate variables in the longitudinal, circumferential, and radial directions were not significantly different between pacing rates. Peak early diastolic torsion rate at 180 bpm was significantly increased compared with that at 120 bpm (P = 0.003). Conclusion: Torsion rate in early diastole was elevated at 180 bpm, which may reflect improved myocardial relaxation with higher HR. Changes in left ventricular torsion during tachycardia may play an important role in preserving stroke volume in the presence of shortened ejection and filling times. (C) 2013 Elsevier B.V. All rights reserved.

OBJECTIVES: To evaluate left ventricular geometry in dogs with various stages of myxomatous mitral valve disease. METHODS: Ninety-seven dogs with myxomatous mitral valve disease classified by the International Small Animal Cardiac Health Council system and 20 weight- and age-matched healthy dogs. Left ventricular long-axis to short-axis ratio, sphericity index in end-diastole and end-systole, left ventricular wall thickness to internal dimension ratio and relative wall thickness were assessed. RESULTS: The diastolic sphericity index was lower in classes Ib, II and III than in healthy dogs (P=0.003, P&lt;0.001 and P&lt;0.001) and was also lower in class III than in classes Ia, Ib and class II dogs (P&lt;0.001, P&lt;0.001 and P=0.002). The relative wall thickness was lower in classes II and III than in class Ia (P=0.003 and P&lt;0.001), class Ib (P=0.004 and P&lt;0.001), and healthy dogs (P&lt;0.001 and P&lt;0.001) and was also lower in class III than in class II (P=0.005). CLINICAL SIGNIFICANCE: Sphericity index and relative wall thickness are simple methods for assessing left ventricular geometry using two-dimensional echocardiography that may be useful in myxomatous mitral valve disease dogs as part of risk stratification.

An 11-year-old spayed female miniature dachshund was evaluated for a 2-month history of chronic vomiting. Abdominal ultrasonography revealed a heterogeneous mass in the pyloric region. Contrast upper gastrointestinal radiography demonstrated impairment of gastric outflow. Endoscopic examination revealed multiple polyps at the gastric pylorus. The pyloric polyps were variable in size, sessile-shaped and pedunculated. Initially, endoscopic polypectomy was attempted, but all the polyps could not be completely resected. Thus, endoscopic polypectomy with argon plasma coagulation was performed to cauterise the lesions. The histopathological diagnosis of the lesions was inflammatory polyps, and a moderate number of Helicobacter spp. was revealed. After the argon plasma coagulation treatment, the dog did not vomit, and improvement of clinical signs was maintained for 13 months. Endoscopic polypectomy with argon plasma coagulation may be useful for mixtures of sessile and pedunculated polyps. The present report may provide a basis for further studies of argon plasma coagulation treatment for canine gastrointestinal polyps. © 2013 British Small Animal Veterinary Association.

Objective: The objective of this study was to clinically assess myocardial deformations in dogs with chronic mitral valve insufficiency (CMVI) using two-dimensional speckle-tracking echocardiography (2D-STE). Animals: 87 dogs with CMVI. Methods: Dogs were placed into 1 of 3 classes, based on the International Small Animal Cardiac Health Council classification. In addition, 20 weight- and age-matched healthy dogs were enrolled as controls. The dogs were examined for myocardial deformations using 2D-STE, and strain and strain rate in the longitudinal, circumferential, and radial directions were evaluated. Results: Class II and III dogs had higher circumferential strain than class I dogs (P = 0.002 and P = 0.001, respectively) and controls (P &lt 0.001 and P &lt 0.001, respectively). Class III dogs had higher radial strain than class I dogs (P = 0.001) and controls (P &lt 0.001). Class III dogs had higher radial strain rate than class I dogs (P = 0.006) and controls (P = 0.001). Other deformations, including longitudinal deformations, were not significantly different between classes of CMVI or between CMVI dogs and controls. Conclusions: In the clinical progression of CMVI in dogs, myocardial deformations, as assessed by 2D-STE, differed according to myocardial contractile direction. Thus, assessments of multidirectional myocardial deformations may be important for better assessment of clinical cardiac function in dogs with CMVI. © 2013 Elsevier B.V. All rights reserved.

Background Left ventricular torsional motion plays an important role for effective pump function. However, noninvasive clinical assessment of torsional deformations by two-dimensional speckle-tracking echocardiography (2D-STE) in dogs with myxomatous mitral valve disease (MMVD) has not been reported. Hypothesis Left ventricular torsion is determined by the native orientation of the helical myocardial fibers, such that it might provide better assessment of myocardial function than conventional methods. Animals Sixty-seven client-owned dogs with MMVD were classified into 3 classes based on the International Small Animal Cardiac Health Council classification and 16 weight- and age-matched healthy dogs. Methods Dogs were examined for myocardial deformations by 2D-STE and were evaluated for peak systolic rotation and rotation rate at each basal and apical view. Dogs also were evaluated for peak systolic torsion and torsion rate. Results Peak systolic torsion was higher in class II than in class I (P&lt;.001) dogs. Peak systolic torsion was lower in class III than in class II (P=.001) dogs and controls (P=.003). Conclusions and Clinical Importance Torsional deformations assessed by 2D-STE differed among clinical classes of MMVD. Myocardial torsional deformations by 2D-STE may provide more detailed assessment of contractile function in dogs with MMVD.

A four-month-old female Labrador retriever was brought to the Tokyo University of Agriculture and Technology Animal Medical Center for examination of its main symptoms of cough, tachypnea and exercise intolerance. Upon examination, the dog was found to have cyanosis and inadequate growth. Echocardiography revealed tetralogy of Fallot. Cardiac catheterization confirmed that the main pulmonary artery was completely occluded and that blood flowed from the aorta to the pulmonary artery. Accordingly, the animal was diagnosed with extreme tetralogy of Fallot.

A 9-year-old spayed female domestic shorthair cat presented with a skin lesion of the left tarsus. The lesion was biopsied and, based on the microscopic appearance and immunohistochemical characteristics, histiocytic sarcoma was diagnosed. Amputation was performed with improved demeanor seen postoperatively. However, between 44 and 60 days following the surgery, relapse of skin lesions appeared in multiple locations, including at the previous amputation site, and euthanasia was elected. This is the first report of a histiocytic sarcoma treated with amputation in a cat.

The double-chambered right ventricle (DCRV) is a rare congenital cardiac disease in dogs, and its detailed epidemiological and morphological features are not clearly understood. By investigating the profile, clinical signs, and characteristics of examination findings of eleven dogs with DCRV by means of a retrospective study, we attempted to clarify the epidemiology and morphology of the condition. The study group consisted of nine males and two females. Breeds included Pug (n=3), Miniature Dachshund (n=1), French Bull-dog (n=1), Shiba (n=1), and Retrievers (n=5). The attachment site of the anomalous muscular bundle was continuous with the cardiac apex in nine dogs, and it was attached to the right ventricle free wall in the other two dogs. In dogs with DCRV, at least one of the following conditions was present concurrently: congenital or acquired tricuspid valve regurgitation (TR), ventricular septal defect, and atrial septal defect. Also, the pressure difference between the two chambers increased over time, and progressive right-sided heart failure was observed. In summary, DCRV occurs in small breeds of dog as well as in large breeds of dog and it may be more prevalent in males. The existence of two types of DCRV in dogs was established. Dog with DCRVs will have a high incidence of concurrent cardiac abnormalities. Concurrent TR may be either congenital or acquired. DCRV is a congenital disorder, but the clinical condition progresses as the dog develops.

A 5 year old neutered male cat was admitted to our hospital in the early morning with sudden onset of bilateral hindlimbs paralysis. Conservative anticoagulant therapy using heparin, warfarin, and dipyridamole, and thrombolytic therapy with urokinase administered by intravenous infusion were started. However, no improvement was noted even after 2 days of treatment, and the cat was started on local intra-arterial administration of urokinase via a catheter on disease day 3. Successful thrombolysis could be accomplished by this approach, and the motor function of both hindlimbs recovered on disease day 5. The cat could be discharged on disease day 9. Complications such as hemorrhage and hyperkalemia were not observed during the thrombolytic therapy. These results suggest that local intra-arterial administration of urokinase may be an effective approach for the treatment of FATE.

It is required not to increase the ventricular rate and to preserve the ventricular systolic function in treating supraventricular tachyarrhythmia (SVTA). The objective of this study is to investigate whether or not Efonidipine hydrochloride (EH), a T and L dual type Ca(2+) channel blocker, suppresses the increasing ventricular rate without reducing the ventricular systolic function using canine SVTA models by rapid atrial pacing (RAP) method. Clinically healthy fourteen beagles were used. The 14 dogs were randomly assigned to the EH-administered group (EH group, n=7) and non-EH-administered group (control group, n=7). The EH group was orally-administered EH at 5 mg/kg SID during RAP. On the other hand, the control group was applied RAP without oral administration of EH. Duration of RAP was for 3 weeks for both groups. The ventricular rate for the EH group was significantly lower than that for the control group. The left ventricular- fractional shortening for the control group declined significantly compared to baseline. Those for the EH group did not show any changes over time and were significantly higher than the control group. The ratio between pre-ejection period and ejection for the EH group were significantly lower than those of the control group. In conclusion, the study demonstrated that EH suppresses the increasing ventricular rate without reducing the ventricular systolic function in canine SVTA model. Therefore, EH is expected to become a new treatment for canine SVTA.

10歳齢のウエストハイランド・ホワイト・テリアが, 失神を主訴とした洞不全症候群の症状の治療のためペースメーカーの設置を受けた. その後, 一般状態は良好に推移していたが, 設置6カ月後に突然の活力低下および腹部膨満を主訴に来院した. 検査により脾臓腫瘤を認めたため, 脾臓全摘手術を行った. 周術期の麻酔薬負荷や手術侵襲を含め, ペースメーカー設置後には頻脈発作は発現しなかった.

左脚ブロックは，刺激伝導障害であり，心疾患と関連してみられることが多い。ヒトにおいて，脚ブロックは左右心室間の収縮運動にずれ（非協調性）を生じ，心機能の低下に発展していくと推測されている^{1, 2)}。我々は，左脚ブロックと診断された2頭のイヌにおいて，従来の心エコー法と組織ドプラ法（TDI法）による測定を行い，TDI法の有用性を検討した。従来の心エコー検査では，左右心室の前駆出時間(PEP)を測定した。TDI法による心室の収縮機能を測定するために，収縮期心筋運動速度のピーク値(Sm)と，左右心室の収縮運動の協調性を調べるために，QRS群の始まりからSmに達するまでの時間(Ts)を測定した。しかし，TDI法による測定値を考察するためのイヌにおける報告がなかったため，正常な心機能をもつ13頭のビーグル犬で同様の測定を行い，それぞれの値を比較した。左脚ブロックの症例において，左室壁，心室中隔壁のTs時間は，右室壁のそれに比較して，明らかに延長した。また，これらの値は，コントロール群と比較すると，明らかに長かった。また，左脚ブロックの症例の左室壁，心室中隔壁のSm値は，右室壁のそれに比較して，明らかに低い値を示し，またコントロール群と比較するとこれらの値は，明らかに低下していた。そして，左右心室壁のTs時間の差と，QRS持続時間の関係をみると，QRS持続時間が長いほど，左右心室壁のTs時間の差が大きくなっていることがわかった。この左右心室壁のTs時間の差とQRS持続時間との関係は，左右心室のPEPの差とQRS持続時間との関係と類似していることが確認された。以上より，左脚ブロックという伝導障害をもつ症例において，TDI法によるTs時間の測定は，左右心室の収縮運動の非協調性の評価に有用であり，またSm値の測定は，心室の運動性の評価に有用であると考えられた。そして，PEPのほか，TDI法によるTs時間を基にして，左右心室間の収縮運動のずれ，つまり非協調性をみることは，心電図検査による電気的な情報を得ることに加え，さらに病態の評価に有用であると思われた。

症例はヒマラヤン，9歳，体重3.2 kgの避妊雌。近医にて心内膜の高エコー所見と胸水貯留などから拘束型心筋症(RCM)と診断され治療を受けていたが，臨床症状の改善がみられないため日本獣医生命科学大学付属動物医療センターに来院した。稟告では活力減退，食欲不振，多飲多尿，呼吸速拍および眼の変色が主訴であった。非観血的血圧測定では収縮期血圧，平均血圧および拡張期血圧はそれぞれ223 mmHg, 189 mmHgおよび158 mmHgであった。著者らは，超音波診断，血中ホルモン濃度測定および血液生化学検査などから，本症例を本態性高血圧症と仮診断した。しかし，この時点では，軽度の心室内膜の高エコー化と不整が認められるためRCMを完全に除外診断することはできなかった。塩酸ジルチアゼム，ACEI，ジピリダモールにより治療を開始した。収縮期血圧は治療前の210～230 mmHgから180～190 mmHgへと低下し，一般状態の改善が認められたため同様の治療を継続した。初診時に認められた心内膜の高エコー化所見は，その後の心エコー検査において認められなくなった。よって，RCMを除外することで本態性高血圧症の診断を下した。その後，一般状態は安定していたが，しばらくして再度，収縮期血圧 200 mmHg以上となり，活力低下と食欲不振などの臨床症状を呈した。そこで，塩酸ジルチアゼムからベシル酸アムロジピンに変更したところ，速やかな血圧下降と臨床症状の改善が認められた。そしてベシル酸アムロジピンの投与開始から5年以上が経過した現在も，収縮期血圧130～160 mmHgと良好な血圧コントロールと臨床状態を維持している。

Circulating immune complexes (CIC) in the sera from 45 clinically healthy cats and 23 feline immunodeficiency virus (FIV) infected cats were measured by an immune adherence hemagglutination (IAHA) method. The level of CIC in the sera from FIV sera-negative healthy cats was 47.2 +/- 47.3 mu g/ml when expressed as heat aggregated feline IgG equivalent value in IAHA reactivity. On the other hand, the level of CIC in the sera from FIV infected cats was 757.4 +/- 910.5 mu g/ml, which was significantly higher than that of healthy ones. CIC levels of 11 symptomatic cats and 12 asymptomatic ones were 837.8 +/- 1138.2 mu g/ml and 683.0 +/- 684.2 mu g/ml, respectively. These results showed that IAHA method was reliable to detect CIC levels of cat sera and that CIC levels in the sera of cats infected with FIV were higher than those of healthy ones.

Circulating immune complexes (CIC) in the sera from 102 clinically healthy dogs and from 16 Dirofilaria immitis (D. immitis) infected dogs were measured by the immune adherence hemagglutination (IAHA) method. The level of CIC in the sera from healthy dogs was 28.2 +/- 29.1 mu g/ml. There was no significant difference in the levels of CIC regarding sexes or ages. On the other hand, the level of CIC in the sera from D. immitis infected dogs was 230.3 +/- 117.1 mu g/ml, which was significantly (p&lt;0.01) higher than that of healthy dogs. The results of this study confirm that IAHA method is one of the reliable means of detecting and/or diagnosing immune complex mediated diseases in dogs.