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Dynamic left ventricular outflow tract obstruction (DLVOTO) is a common condition in cats and humans. In this case report, a dog is described with DLVOTO secondary to severe intra-abdominal hemorrhage caused by a hemangiosarcoma. The dog was a 9-year-old, 35.7-kg, spayed female German Shepard dog that presented with a history of tachypnea and collapse. A Levine II/VI systolic murmur was present at the heart base. Abdominal ultrasonography revealed a splenic mass and a large amount of ascites. Echocardiography showed a reduced left ventricular diameter and an increased aortic velocity caused by systolic anterior motion (SAM) of the mitral valve apparatus. The heart murmur and the SAM were resolved after treatment including a splenectomy and a blood transfusion.

The aim of this study was to examine the pharmacokinetics of nicorandil, a hybrid of an adenosine triphosphate-sensitive potassium channel opener and a nitrate, and to estimate its clinical doses in dogs with mild mitral valve regurgitation (MR). Nicorandil (0.1, 0.3, and 1.0 mg/kg) was administered orally to normal dogs and those with experimentally-induced MR, and its plasma concentrations were analyzed using high-performance liquid chromatography. Plasma concentrations increased dose-dependently after the administration of nicorandil, and were not different between normal dogs and those with MR. Similar to the effective plasma values obtained in cardiac disease in humans, the findings of this pharmacokinetic study may indicate that a dose of 0.3-1.0 mg/kg has the same effectiveness in dogs with cardiac dysfunction.

Background— Respiratory support therapy significantly improves life span in patients with Duchenne muscular dystrophy; cardiac-related fatalities, including lethal arrhythmias, then become a crucial issue. It is therefore important to more thoroughly understand cardiac involvement, especially pathology of the conduction system, in the larger Duchenne muscular dystrophy animal models such as dystrophic dogs. Methods and Results— When 10 dogs with canine X-linked muscular dystrophy in Japan (CXMD J ) were examined at the age of 1 to 13 months, dystrophic changes of the ventricular myocardium were not evident; however, Purkinje fibers showed remarkable vacuolar degeneration as early as 4 months of age. The degeneration of CXMD J Purkinje fibers was coincident with overexpression of Dp71 at the sarcolemma and translocation of μ-calpain to the cell periphery near the sarcolemma or in the vacuoles. Immunoblotting of the microdissected fraction showed that μ-calpain–sensitive proteins such as desmin and cardiac troponin-I or -T were selectively degraded in the CXMD J Purkinje fibers. Utrophin was highly upregulated in the earlier stage of CXMD J Purkinje fibers, but the expression was dislocated when vacuolar degeneration was recognized at 4 months of age. Nevertheless, the expression of dystrophin-associated proteins α-, β-, γ-, and δ-sarcoglycans and β-dystroglycan was well maintained at the sarcolemma of Purkinje fibers. Conclusions— Selective vacuolar degeneration of Purkinje fibers was found in the early stages of dystrophin deficiency. Dislocation of utrophin besides upregulation of Dp71 can be involved with this pathology. The degeneration of Purkinje fibers can be associated with the distinct deep Q waves in ECG and fatal arrhythmia seen in dystrophin deficiency.

犬の動脈管開存症(Patent Ductus Arteriosus=PDA)は,我が国における小動物の先天性心疾患としては最も多い疾患であるが,外科的結紮ならびにコイル塞栓術による根治的治療を実施し,術後臨床症状の明らかな改善が認められる症例において,左室内径短縮率(FS)が低下する例が報告されている。本研究はこれまで得られた臨症例を用いて,PDA治療後におけるFS値低下の原因解明を目的に,動脈管閉鎖術前後のFS値および心拍出量(CO)を測定し,FS値の低下と回復の程度に関与する因子について検討を加えた。供試症例の概要および検査方法 2003年4月から2004年4月までの約1年間に,麻布大学獣医学部付属動物病院に来院し,各種検査によりPDAと診断されたイヌ15例を用い治療を実施した。動脈管閉鎖術として7症例にコイル塞栓術を実施し,8症例に対しては開胸術によるジャクソン法を用いて結紮術を行なった。術後の検査方法としては,X線検査は,PDA閉鎖術前,3日後,1週間後ならびに1ヶ月後に実施し,椎骨心臓サイズ(VHS)ならびに心胸郭比(CTR)を用いて評価した。超音波検査では,FS値ならびにCOの測定をPDA閉鎖術前,3日後,1週間後,1ヶ月後で実施した。血圧測定としては,コイル塞栓術を行なったPDA閉鎖直前と直後の動脈血圧を観血的にトランスデュサーにて測定し,その値から体血管抵抗を算出した。成績: 1)心拡大および二次的なMR合併の両者が認められた症例(n=9)の成績 9症例中1例(症例13)を除外した他の全ての例において,術前のVHSが11以上を示し,心拡大が認められた。術前と術後の比較では,全ての症例で術後FS値の低下が認められた。心拡大は術後,徐々に軽減し,また,術後のCOは正常範囲内にあった。2)MRの合併は認められず,軽度心拡大のみが認められた症例(n=2)の成績 : 2例共にVHSが11Vを示し,術前から術後1ヶ月のFS値の変化では,各症例ともにFS値の低下が認められた。しかしながら,COは正常範囲内であった。また,1例(症例8)では術後1ヶ月の時点で12ヶ月齢に達し,他の1例と比較してCOがやや低い結果となったが,12ケ月齢としては正常範囲内であった。3)心拡大およびMRの合併の両者が認められなかった4症例 : 各症例共に術前無徴候であり,PDAの特徴的な心雑音および超音波検査におけるPDAの乱流以外の所見は確認されなかった。術後の超音波検査によりFS値の低下が確認されたが,COは正常範囲内であった。考察 通常心エコー検査において,正常値を下回る低いFS値を示す症例では心不全徴候が認められる。これまでPDAの閉鎖術後にFS値が低下することが報告されている。原因として,心不全の発現があると報告されている【3】。今回の成績から,全症例で認められたFS値の有意な低下が心収縮力の低下に伴うCOの減少を伴うとすれば,同時に臨床症状の悪化が懸念された。しかしながら,術前と比較し,全ての症例において術後,CO値の低下は認められたものの,正常犬のCOより減少する例は確認されなかった。さらに,術後,心不全徴候を示す症例が確認されなかったと同時に,臨床症状の明らかな改善が認められたこと,また全ての症例において心陰影の縮小傾向が認められたことは,術後,FS値の低下からCOが減少しているとは考えられず,十分な心筋機能が維持されていたものと推察された。, Patent ductus arteriosus (PDA) is the most common congenital heart disease of small animals in our country. For such cases, radical treatment is carried out by surgical ligation and coil embolisation, and it is found that the value of the left ventricle fractional shortening (FS) falls in the case that clear improvement of clinical symptoms are recognized after treatments. This study is aimed for elucidation of FS fall to be able to put after PDA treatment using clinical cases. And also cardiac output (CO) was measured and the factors which related in degree of a fall and recovery of FS value were evaluated. Case study and methods The treatment of 15 PDA cases which were introduced to Animal Hospital of Azabu University for about 1 year from April 2003 to April 2004, were carried out. Coil embolisation for seven cases and Jackson method by thoracotomy for eight cases were performed for closure of ductus. X-ray examination was carried out at preoperatively, three days later, one week later and one month later of PDA closure. The vertebral heart size (VHS) and cardio-thoracic ratio (CTR), for a postoperative examination, were evaluated. Echocardiogram was carried out for evaluate FS and the measurement of CO values three days and one week later. Arterial blood pressure just after and before closure of the PDA was measured and the general vascular resistance from the value was calculated. Results : 1) Results for nine cases with heart enlargement and secondary MR. In other cases which excluded one case (case 13) in nine cases (n=9) the heart enlargement was found by measured VHS (VHS=11) and the secondary MR preoperatively. By pre and postoperative comparison, a fall of FS value was accepted for all cases postoperatively. Enlargement of the heart was gradually reduced after closing, and CO values became normal range. 2) Results of two cases without MR and with slight heart enlargement. VHS showed 11 vertebra of 2 cases together. By a change of FS value from pre-to postoperation during one month, a fall of FS value was approved in each case. However, there was CO in the normal range. In addition, in one case (case 8) CO was slightly low in comparison with other case. 3) Results of four cases without cardiac enlargement and MR. Each case was preoperatively no sign except the characteristic cardiac murmur and the turbulence by the PDA flow in pulmonary artery using echocardiogram. A fall of FS value was confirmed by postoperative echocardiogram, but CO value was in the normal range. Discussion In echocardiogram, heart failure sign is usually recognized for a case to show low FS value which is less than a normal value postoperatively. After PDA closure, FS value fall was reported.And also it is reported that there is expression of heart failure as a cause. If a fall of FS value was accompanied with decrease of CO with a fall of cardiac contractile force for all cases, aggravation of a clinical symptom was concerned at the same time by this results. However, in comparison with preoperation, although the fall of CO value was found in all cases, the cases which decreased less than CO of a normal dog were not confirmed. Furthermore, although the cases which show the heart failure were not recognized, the clear improvement of a clinical symptom was found, and a reduction of heart size was recognized in all cases. It was suggested that myocardial function was maintained sufficiently though a fall of FS value was recognized at the same time postoperatively.

The purpose of this study was to evaluate the feasibility, safety, and efficacy of transcatheter closure in dogs with a congenital perimembranous ventricular septal defect (VSD) using a detachable coil. No dogs showed any symptoms, and chest X-ray and ECG were normal. The diameters of VSD ranged from 2 to 4mm on echocardiogram. The defect was 2 to 2.5mm from the aortic valve. A detachable coil (size 5mm with 5 loops) designed for patent ductus arteriosus (PDA) was delivered via the transarterial route. The device was successfully employed in all dogs. A minimal residual shunt was observed in all dogs even though Qp/Qs decreased. Hemolysis and a rate-dependent right-bundle branch block were observed in 1 dog, but there was no clinical significance. No major complication was noted. Pathological examination after 1 year revealed that the coils were covered with tissue without significant damage to the His-Purkinje conduction system. In conclusion, transcatheter closure of a small perimembranous VSD using a detachable coil can be achieved without major complications or significant pathological damage at the lesion site.

ACE and chymase play crucial roles in the establishment of pressure overload-induced cardiac hypertrophy. In the present study, time sequences of ACE and chymase-like activities, and their correlation with hypertrophic changes including free wall thickness and cardiac fibrosis, were elucidated in dogs with constant pressure overload to the right ventricle. Pulmonary artery banding (PAB) was applied so that the diameter of the main pulmonary artery was reduced to 60% of the original size, right ventricular pressure was elevated by about 70%, and pulmonary artery flow was increased by about three times of that in sham operation groups. These increases remained unchanged 15, 60, and 180 days after PAB, suggesting that constant right ventricular pressure overload was obtained, at least during this period. The diameter of the right ventricular myocyte was slightly increased and the percentage of fractional shortening was decreased 15 days after PAB. Right ventricular wall thickness and interstitial collagenous fiber were, however, not different from those of sham-operated dogs, suggesting that this period is a period of adaptation to the overload. Sixty days after PAB, the diameter of the right ventricular myocyte was further increased, and right ventricular wall thickness and interstitial collagenous fiber were also increased. These changes were almost identical even 180 days after PAB. Thus, stable hypertrophy was elicited from 60 through 180 days after PAB. ACE activity was facilitated at the adaptation period to the overload (15 days after PAB), but chymase activity was not facilitated at this period. On the other hand, both ACE and chymase-like activities were unchanged in the earlier phase (60 days after PAB) of stable hypertrophy, but facilitated in the latter phase (180 days after PAB). These findings suggest the pathophysiologic roles of these enzymes may be different over the time course of pressure overload-induced hypertrophy.

1.16S rDNA(一部)の塩基配列を解析することにより,チーターに感染するH属菌が少なくとも4種類あることがわかり,PCR-RFLP解析により,それらを3つのグループに分けることが可能であった。ブタでは少なくとも3種類のH属菌の感染が確認でき,胃内での存在部位により菌種が異なっていることがわかった。2.PCRは糞便サンプルからのCPVの検出および型判別に有効であることを確認した。まず,CPV-2型かCPV-2bまたは-2bかを検出し,後者だった場合は,さらにCPV-2bの判別をすることが可能だった。4.DNA鑑定により,本個体は通常の雌と同様にXX型染色体を示すが,雄特有のSRY遺伝子ももっている(おそらく減数分裂時の組換えによる)ことから半陰陽になったと考えられた。, Four independent studies were carried out. They were: 1. Species identification by genome analyses of the genus Helicobacter that infected the cheetah, the swine and the monkey; 2. Usefulness of PCR-detection of viral genes in fecal samples from canine parvovirus infected dogs;3. Sexing of birds by DNA analyses; and 4. DNA-sexing of a case of hermaphroditism found in a miniature dachshund. Results from each study will be described separately. 1. Helicobacter Nucleotide sequence homology was examined for PCR-amplified segment of 16S rDNA to differentiate the Helicobacter species. The cheetah samples were classified into four species, including the closely related Flexispira rappini. On the basis of restriction site distribution, these were more conveniently grouped into three RFLP criteria, one consisting of the two Helicobacter species. Three Helicobacter species were identified in swine specimens, one at the fundus or pylorus, and two at the cardia. Although the three species from simian samples were highly homologous to the human bacteria, they were considered to be unique to monkeys after phylogenetic analysis. 2. Canine parvoviras (CPV) Fecal samples proved to be convenient and satisfactoty materials for differential PCR detection of CPV. With the first step primers CPV was divided into CPV-2 and a combination of its two subtypes. The second set of primers further divided the latter into CPV-2a and CPV-2b, thus clearly identifying the three known antigenic types of CPV by using dog feces. 3. Avian sexing The avian sex chromosomes (W and Z) carries chromobox helicase-DNA binding (CHD) protein genes with its intron differing in length by sex. Taking advantage of the differences of this and the nucleotide sequence of sex chromosome-linked EE 0.6 region, the two PCR methods successfully identified snowy owl's sex (using blood sample), and the CHD-PCR, chicken's (using feather). 4. Sexing of a hermaphroditic dog The highly accurate PCR/RFLP method we previously reported was applied to sexing of a case of hermaphroditic miniature dachshund that possessed a mixed external and internal genitalia. DNA from its nail showed that this dog had XX chromosome set and (essentially Y-specific) SRY sequence. It was concluded that this originally female dog had somehow acquired SRY segment, presumably during meiosis in one of its parents.

Objective—To assess autonomic function in dogs with mild mitral regurgitation (MR) that did not have clinical signs of the condition. Animals—6 healthy adult Beagles. Procedure—Mild MR was experimentally induced. A 24-hour ambulatory ECG was recorded before and after induction of MR. Heart rate variability was analyzed in frequency domains by use of the ambulatory ECG. Low-frequency (LF) and high-frequency (HF) power were calculated by integrating over their frequency intervals, and the ratio of LF to HF was also calculated. Measurements of frequency domains were analyzed for 4 time periods (midnight to 6 AM, 6 AM to noon, noon to 6 PM, and 6 PM to midnight). Results—Dogs with experimentally induced MR were classified as International Small Animal Cardiac Health Council class Ia. The HF power of dogs with MR was significantly decreased between 6 AM and noon. The ratio of LF to HF in dogs with MR was significantly increased for the periods between midnight and 6 AM, 6 AM and noon, and noon and 6 PM. Conclusions and Clinical Relevance—Compensatory response through autonomic modulation was observed in dogs with mild MR that did not have abnormalities, except for cardiac murmur, during clinical examination. This result suggests that treatment during the early stages of mild MR may be beneficial. Additional studies are necessary to determine whether such treatment will delay the onset of congestive heart failure and prolong survival in dogs affected with mild MR. (Am J Vet Res 2003; 64:145–148)

An anomalous shunt between the bronchoesophageal artery and pulmonary artery was diagnosed in a 1-year- old, 3.5 kg female Miniature Dachshund by selective contrast angiography. A cardiac murmur had been observed in the dog during examination at another hospital. The machinery murmur was auscultated at the left side of the base of the heart. Although thoracic radiography revealed mild cardiomegaly, the characteristic findings of patent ductus arteriosus (PDA), including as aortic arch enlargement and pulmonary artery enlargement were not observed. Echocardiography demonstrated shunting of blood flow presumably from the arterial duct at the pulmonary artery carina. Based on the above findings the case was diagnosed as PDA. Angiocardiography was performed to confirm the diagnosis in preparation for surgical treatment, but later we confirmed that the shunt vessel was not PDA, but apparently a branch of the bronchoesophageal artery. The shunt vessel was branching in a complicated manner and shunted to the pulmonary artery.

A new chemolytic therapy with amino acid preparation was tried for use on struvite renal stones in two dogs, which were admitted to Azabu University Veterinary Teaching Hospital. No other special diet, for the purpose of dissolving the stones, was fed during the treatment. Dissolution of the stones began at week 1, and no stone was detected on radiography at week 4 in both cases. The amino acid preparation thereafter has been administered every 2-3 days to prevent formation of the stones. After 6 months from treatment, complete dissolution was confirmed, and no relapse has been observed. Therefore, it is concluded that chemolytic therapy with amino acid preparation might be useful for the treatment of nephrolithiasis with struvite renal stones in dogs.

The oscillometric procedure was used to measure the heart rate as well as the systolic, mean, and diastolic blood pressures of 152 dogs (102 in the control group, 13 in the group with renal disease, 37 in the group with heart disease) who were brought to Azabu University of Veterinary Teaching Hospital. It was demonstrated that the blood pressure and heart rate of the control group lowered and tended to become stable as the number of measurements increased. No appreciable difference was identified in the measurements of either blood pressure or heart rate in the forelimbs and tail head. With regard to gender, males showed a significantly higher value than females (p < 0.05). No interaction was identified between age and blood pressure. No difference was identified in the heart rate in all groups. In an investigation of blood pressure in all groups, the renal disease group showed significantly higher values (p < 0.05) than either the control or the heart disease group in all values of systolic, mean and diastolic pressures. These results indicated that dogs with renal disease can manifest hypertension.

We studied the relationship between the degree of mitral protrusion and degree of mitral regurgitation in an experimental model in which the degree of mitral protrusion could be adjusted. The model was developed by dissecting the dorsal papillary muscle through a left atriotomy in 5 dogs and re-attaching the papillary muscle to the original site using a single mattress suture threading through the epicardium under cardiopulmonary bypass. By manipulating the suture from a position outside the epicardium, the degree of mitral protrusion could be adjusted. The long-axis view of the mitral valve was imaged by B-mode echocardiography with the transducer placed directly over the surface of the right ventricular outflow tract. The height (H) from the coaptation point or tip of the protruded cusp in relation to the mitral annular plane was measured as an index of mitral protrusion. Mitral regurgitation as a result of the mitral protrusion decreased the left ventricular systolic pressure, and increased the heart rate, mean left atrial pressure (LAPm), and ratio of left ventricular end-diastolic dimension to body weight (LVEDD/BW). H was negatively correlated to LAPm and LVEDD/BW (r = -0.723 and -0.697, respectively). Our results indicated that H expresses not only the degree of mitral protrusion but also the degree of mitral regurgitation, and were in agreement with the previous findings obtained on dogs with spontaneous mitral regurgitation.

脊椎動物の生殖制御に関与する遺伝子を探索するため,有性生殖および雌性生殖をするギンブナ(Carassius auratus langsdorfi)を実験材料として,ディファレンシャルディスプレイ法により各卵巣に発現する遺伝子を比較した。その結果,生殖制御に関与する1つの候補遺伝子断片であるKD16を得た。このKD16には少なくとも5つの対立遺伝子があり,対立遺伝子特異的なプライマーによるRT-PCR法およびRT-PCR-RFLP法により,有性生殖と雌性生殖の卵巣の間では,それらの発現パターンが異なっていることがわかった。また,KD16遺伝子の発現は卵巣特異的であると思われた。さらに,5'RACE法によりKD16遺伝子のcDNA(約1.7kb)の全長を決定し,相同性検索を行ったところ,RINGドメインとB-boxドメインをもつTRIM(Tripartite motif protein family)と呼ばれる一群のタンパク質の一つと考えられた。, The Japanese silver crucian carp, a rare but ideal model animal for investigation of genes that could regulate mode of vertebrate reproduction. These fish naturally occur in normal bisexual diploid form as well as their triploid gynogenetic counterparts. Notably, the latter form reproduce themselves by parthenogenetic, or clonal, development of unreduced and unfertilized eggs, thus giving rise to genetically identical all-female offspring. The primary objective of this study was to identify and analyze genes that play crucial roles in the complicated cascade or network for induction of meiotic division to produce the gametes in almost all multicellular organisms at the final step of formation of their germ cells. In gynogenetic fish that skip meiosis and lay triploid eggs whose genomes are identical to that of somatic cells, a certain set of genes must be different from that of bisexual kin. This difference was studied by comparing genes and their expression in the ovaries of both diploid and triploid fishes. Namely, ovarian RNAs were extracted and compared between the two forms for their nucleotide sequences and subtype variation. Differential-display analyses for RT-PCR products resulting from twenty different primer sets singled out a convincing candidate gene fragment referred to as KD16 that could be linked to mechanism for regulation of germ cell differentiation. This gene was shown to have five or more alleles, each of which was expressed differently between diploid and triploid fishes and appeared to be ovary-specific. The entire stretch (approx. 1.7 kb) of cDNA of KD16 gene obtained by 5' RACE method was analyzed for its nucleotide sequence and searched for homology with data-bank sequences. The results indicate that each of five subtypes encodes the "TRIM proteins", i.e., proteins with the RING domain and the B-box domain. This implies a possible role of this gene in reproductive regulation.

Renal transplantation was performed on 6 cats with chronic renal failure. Clinical signs and the blood chemistry findings (BUN, Cr, IP) improved one week after renal transplantation. Renal anemia also improved 3-4 weeks after surgery. Two cases had the same complications, hydronephrosis and hydroureter within 1 or 2 weeks of surgery, evidenced by marked elevations of BUN and Cr, suggesting that ureteral obstruction at the site of ureterocystostomy is the main complication of renal transplantation in cats. As a new resolution for this problem, we transplanted the ureter with the intact ureteral opening of the bladder from the donor in the remaining 4 cats. Ureteral obstruction was not observed in them, thus the procedure was considered to be useful for avoiding this complication. Two cats died of pneumonia and other complications within 3 months. There were no acute rejections or side effects from the immunosuppressant during the observation period in the remaining four cats.

膝関節前十字靱帯再建術における重要なファクターには再建材料の種類, その固定部位, 固定方法, 固定時の膝関節角度等があるが, 犬で生体力学的に検討した報告は著者の知るかぎりではない。そこで関節内法および関節外法において, 膝関節の可動域における再建靱帯の固定間距離の計測を行い, 手術時における至適固定部位について検討を加えた。その結果, 最も等長性が保たれた部位は関節内法では前十字靱帯脛骨側付着部の前内側部と前十字靱帯大腿骨側付着部の後上縁の組み合わせであった。また, 関節外法では外側ファベラと脛骨粗面近位の組み合わせが最も良好であり, 伸展位で固定すべきであると考えられた。

Mitral valvuloplasty (MVP) is used in dogs with refractory mitral regurgitation (MR); however, it is difficult to tie the artificial chord, i.e., the expanded polytetrafluoroethylene suture, at the planned height of the mitral valve, because of the slippery nature of the knot. The loop technique has resolved these difficulties in humans. Premanufactured loops (length, 8.0-15.0 mm with 1.0-mm increments) were used in the new modified loop technique. In the current study, cardiac murmurs disappeared, and the MR markedly improved or completely disappeared approximately 3 months after surgery in 3 dogs. Therefore, this new technique might be effective in dogs.

This study investigated the long-term survival of a calf with cervical ectopia cordis that grew normally, became pregnant, and calved normally. The cow showed normal cardiac function and absence of peripheral circulation abnormalities. This paper documents antemortem characteristics of the affected cow.

Background Two-dimensional speckle tracking echocardiography (STE) is a relatively new method to detect regional myocardial dysfunction. To assess left ventricular (LV) regional myocardial dysfunction using STE in Duchenne muscular dystrophy model dogs (CXMDJ) without overt clinical signs of heart failure. Methods Six affected dogs, 8 carrier dogs with CXMDJ, and 8 control dogs were used. Conventional echocardiography, systolic and diastolic function by Doppler echocardiography, tissue Doppler imaging (TDI), and strain indices using STE, were assessed and compared among the 3 groups. Results Significant differences were seen in body weight, transmitral E wave and E' wave derived from TDI among the 3 groups. Although no significant difference was observed in any global strain indices, in segmental analysis, the peak radial strain rate during early diastole in posterior segment at chordae the tendineae level showed significant differences among the 3 groups. Conclusions The myocardial strain rate by STE served to detect the impaired cardiac diastolic function in CXMDJ without any obvious LV dilation or clinical signs. The radial strain rate may be a useful parameter to detect early myocardial impairment in CXMDJ.

Serial combinations of immunosuppressive drugs (mizoribine: Mi, azathioprine: Az, and prednisolone: Pr) were administered for renal heterotopic allotransplantation in 50 mixed-breed dogs and 4 beagle dogs. The dogs were randomly divided in 5 groups depending upon immunosuppressive protocols. All immunosuppressive protocols were started at 5 days prior to transplantation and discontinued on the eighth day after transplantation. The mean survival time for the allograft recipients in the group receiving Az and Pr [Az (2.5) & Pr group; Az dosage, 2.5 mg/kg once a day with Pr] was 16.2±2.4 days and in the group receiving Az, Mi, and Pr (Mi & Az & Pr group; Mi dosage, 5.0 mg/kg once a day with Az and Pr), it was 14.0±2.6 days. These results were significantly longer than the control group (mean survival time, 8.7±2.4 days; P

In this study, Recirculation Peritoneal Dialysis (RPD) apparatus using a pump to circulate the dialysate was devised and its dialysis efficiency was investigated. In the experiment, 15 mongrel dogs with body weights of 6.6 +/- 0.7 kg were used. The surgery to induce azotemia was performed on the dogs, a disk catheter for drainage was placed between the liver and diaphragm, and a straight catheter for infusion was placed on the abdominal side of the bladder. RPD was conducted using 2 l of dialysate containing 1.3% glucose, and the dialysate was circulated by a pump through the peritoneal cavity and the dialysate chamber at the circulation rates of 30, 60, 90 and 120 ml/min. RPD was conducted for 3 hr and the clearances of urea nitrogen, creatinine, inorganic phosphorus and potassium were recorded every hour. The clearances in RPD became higher with an increase in the circulation rate. Although RPD requires two catheters in the peritoneal cavity, it has no appreciable technical difficulty in handling and is considered to be easier than hemodialysis. RPD enabled higher dialysis efficiency to be achieved in a short time compared with conventional peritoneal dialysis. It seems reasonable to conclude that RPD is a useful new dialysis technique for animals.

超音波ドップラー血圧計による血流音のモニターの有用性を麻酔および手術下の犬を用いて検討した。この装置による非観血的血圧測定値は, 観血的測定値と良く相関した。血流音は平均血圧が約70mmHgになると聴取不可能となったが, この範囲内ではその強さと血圧の測定値と良く相関するように思われた。しかし, 麻酔覚醒期などの動物の不安定な状態下では, 必ずしも良好な相関関係は得られなかった。一方, 血流音のパターンと末梢循環についてみると, 平圧がほぼ一定している場合にも血流音パターンの変化が認められた。このことは血流音が末梢循環動態の変化をより良く反映する可能性を示唆するものであった。

Objective—To compare the effects of candesartan cilexetil and enalapril maleate on right ventricular myocardial remodeling in dogs with experimentally induced pulmonary stenosis. Animals—24 Beagles. Procedures—18 dogs underwent pulmonary arterial banding (PAB) to induce right ventricular pressure overload, and 6 healthy dogs underwent sham operations (thoracotomy only [sham-operated group]). Dogs that underwent PAB were allocated to receive 1 of 3 treatments (6 dogs/group): candesartan (1 mg/kg, PO, q 24 h [PABC group]), enalapril (0.5 mg/kg, PO, q 24 h [PABE group]), or no treatment (PABNT group). Administration of treatments was commenced the day prior to surgery; control dogs received no cardiac medications. Sixty days after surgery, right ventricular wall thickness was assessed echocardiographi-cally and plasma renin activity, angiotensin-converting enzyme activity, and angiotensin I and II concentrations were assessed; all dogs were euthanatized, and collagenous fiber area, cardiomyocyte diameter, and tissue angiotensin-converting enzyme and chymase-like activities in the right ventricle were evaluated. Results—After 60 days of treatment, right ventricular wall thickness, cardiomyocyte diameter, and collagenous fiber area in the PABNT and PABE groups were significantly increased, compared with values in the PABC and sham-operated groups. Chymase-like activity was markedly greater in the PABE group than in other groups. Conclusions and Clinical Relevance—Results indicated that treatment with candesartan but not enalapril effectively prevented myocardial remodeling in dogs with experimentally induced subacute right ventricular pressure overload.

Three dogs presented for the evaluation of cardiac murmurs were diagnosed with aberrant arteriovenous shunts. All cases demonstrated the following findings: 1) relatively soft continuous murmur loudest at the left heart base resembling patent ductus arteriosus (PDA); 2) shunt flow signals in the pulmonary artery on echocardiography; and 3) no PDA on selective angiography, but evidence of anomalous shunting vessels from thoracic aorta to pulmonary vasculature. An aberrant arteriovenous shunt should be considered when a continuous murmur of relatively small intensity is heard.

The load-reducing effect of nitroglycerin (NTG), a vasodilator, was studied in dogs with heart failure. The chordae tendineae of the mitral valve were transected to induce acute mitral regurgitation (MR) for hemodynamic evaluation. By such surgical treatment, preload indices such as left ventricular end-diastolic pressure (LVEDP) and left atrial pressure (LAP) increased significantly, and subsequent cardiac dysfunction and heart failure were indicated by another decrease in stroke volume, myocardial contractility, forward flow, and myocardial oxygen consumption. To dogs with artificially established acute MR, 3 micrograms/kg/min of NTG was administered intra-arterially by means of a continuous infusion, that resulted in decrease of LVEDP, LAP and central venous pressure (CVP). Thus, a reduction of preload was determined. Simultaneously, afterload indices such as aortic systolic pressure (Aos), aortic mean pressure (Aom) and total peripheral resistance (TPR) decreased remarkably. Afterload reduction depended on the amount of venous return; therefore, an extra-corporeal circulation system was applied in order to supply a constant venous return before NTG administration. This caused a significant decrease in aortic diastolic pressure (Aod), Aos, Aom, left ventricular systolic pressure (LVSP) and TPR, and an increase in myocardial contractility and cardiac output. This suggested that afterload reduction might be realized by the vasodilatory effect of NTG on the resistance vessels.

An arterial oxygen tension (PO2) sensor was used to measure the myocardial PO2 at three sites in the left ventricle supplied by the paraconal interventricular branch of the left coronary artery, cranial descending coronary artery (CDCA): a subendocardial site, a subepicardial site and an intermediate point in the left ventricular wall. At first, the PO2 sensor had been compared with the values from a blood gas analyzer. The regression equation Y = 1.4X-4.9 with a correlation coefficient of 0.993 indicated a high correlation between these two measurements. The PO2 of the arterial blood in the left ventricular cavity was assigned an index value of 100%. The PO2 was about 70% in the subendocardial myocardium, about 15% in the mid-ventricular wall myocardium and 9% in the subepicardial myocardium, demonstrating a decreasing PO2 gradient from the endocardial to the epicardial surface. A transient occlusion of the CDCA confirmed the pathway of myocardial oxygen supply. In the mid-ventricular and subepicardial myocardium, marked hypoxia occurred after occlusion of the CDCA. Release of the occlusion resulted in a rapid return to the normal PO2 level. The oxygen supply to these sites is strongly influenced by coronary artery blood flow. The PO2 in the subendocardial myocardium was not dependent on the cranial descending coronary artery. Oxygen appears to be probably supplied through arterial blood in the left ventricle via the endocardium.

Using adult mongrel dogs, experiments were performed to elucidate the relationship between the changes in the myocardial oxygen tension (PmO2) in anoxia and disturbances of cardiac function. Dogs, forced to inspire 100% N2, suffered from a respiratory arrest after 5 min, and developed acute anoxia. However, by 100% O2 inhalation 2 min after the onset of the respiratory arrest, the anoxia rapidly resolved. The arterial oxygen tension (PaO2), left intra ventricular oxygen tension (PLVO2) and PmO2 showed the most pronounced fall 2 min after the respiratory arrest induced by N2 inhalation. The arterial carbon deoxide tension (PaCO2) decreased until the respiratory arrest, after which it started to rise. When inhalation of 100% O2 was initiated at the anoxia, the PaO2, PLVO2 and PmO2 recovered within 1 min followed by a rise beyond the baseline value. Left ventricular end-diastolic pressure (LVEDP), left atrial mean pressure (LAm), left ventricular systolic pressure (LVSP), aortic mean pressure (Aom), maximum rate of force development by left ventricle (LVmax.dp/dt), total peripheral resistance (TPR), cardiac output (CO) and heart rate (HR) were measured. At the onset of anoxia, these parameters decreased sharply. When inhalation of 100% O2 was initiated within 2 min of the respiratory arrest, these disturbances of cardiac function recovered rapidly. The fall of PmO2 plays an important role in the impairment of cardiac function.

Objective—To investigate whether the tissue and plasma renin-angiotensin-aldosterone system (RAAS) is activated in dogs with mild regurgitation through the mitral valve and determine the contribution of chymase and angiotensin-converting enzyme (ACE) to the activation of the RAAS and potential production of angiotensin II during the chronic stage of mild mitral valve regurgitation. Animals—5 Beagles with experimentally induced mild mitral valve regurgitation and 6 clinically normal (control) Beagles. Procedures—Tissue ACE and chymase-like activities and plasma RAAS were measured and the RAAS evaluated approximately 1,000 days after experimental induction of mitral valve regurgitation in the 5 dogs. Results—Dogs with experimentally induced mitral valve regurgitation did not have clinical signs of the condition, although echocardiography revealed substantial eccentric hyper- trophy. On the basis of these findings, dogs with mitral valve regurgitation were classified as International Small Animal Cardiac Health Council class Ib. Plasma activity of renin and plasma concentrations of angiotensin I, angiotensin II, and aldosterone were not significantly different between dogs with mitral valve regurgitation and clinically normal dogs. Tissue ACE activity was significantly increased and chymase-like activity significantly decreased in dogs with mitral valve regurgitation, compared with values in clinically normal dogs. Conclusions and Clinical Relevance—The tissue RAAS was modulated without changes in the plasma RAAS in dogs with mild mitral valve regurgitation during the chronic stage of the condition. An ACE-dependent pathway may be a major route for production of angiotensin II during this stage of the condition.

The objective of this study was to evaluate the hemodynamics of the anesthetic isoflurane in healthy cats given angiotensin-converting enzyme inhibitor (ACEI). The 7 healthy young cats and 3 old cats were received placebo or enalapril 0.5 mg/kg orally. The change in systolic arterial pressure from the baseline to 30 min postanesthesia in the ACEI group was significantly higher than in the placebo group (mean +/- SD: -39 +/- 13% vs. -17 +/- 12%, respectively). The present study indicated that general anesthesia may induce hypotension after the administration of an ACEI.

Objective— To describe use of coil embolization to occlude residual flow through a patent ductus arteriosus (PDA) after incomplete surgical ligation. Study Design— Clinical study. Animals— Dogs (n=4) with continuous murmur after surgical ligation of PDA. Methods— After PDA ligation, residual ductal flow through the PDA was visible on color-flow Doppler examination and left ventricular end-diastolic diameter remained increased. Coil embolization by an arterial approach was performed to achieve complete occlusion of the PDA. Results— Embolization coils were delivered without complications and hemodynamically successful occlusion was achieved. Doppler-visible flow resolved in 2 dogs within 3 months after embolization. Left ventricular end-diastolic diameter indexed to body weight decreased in all dogs. Conclusions— Transcatheter coil embolization appears to be a safe and minimally invasive procedure for complete occlusion of residual PDA flow after incomplete surgical ligation. Clinical Relevance— Transcatheter coil embolization should be considered for correction of hemodynamically significant residual shunts in dogs that have incomplete PDA occlusion after open surgical ligation.

Background Cardiac mortality in Duchenne muscular dystrophy (DMD) has recently become important, because risk of respiratory failure has been reduced due to widespread use of the respirator. The cardiac involvement is characterized by distinctive electrocardiographic abnormalities or dilated cardiomyopathy, but the pathogenesis has remained obscure. In research on DMD, Golden retriever-based muscular dystrophy (GRMD) has attracted much attention as an animal model because it resembles DMD, but GRMD is very difficult to maintain because of their severe phenotypes. We therefore established a line of dogs with Beagle-based canine X-linked muscular dystrophy in Japan (CXMDJ) and examined the cardiac involvement. Methods The cardiac phenotypes of eight CXMDJ and four normal male dogs 2 to 21 months of age were evaluated using electrocardiography, echocardiography, and histopathological examinations. Results Increases in the heart rate and decreases in PQ interval compared to a normal littermate were detected in two littermate CXMDJ dogs at 15 months of age or older. Distinct deep Q-waves and increase in Q/R ratios in leads II, III, and aVF were detected by 6–7 months of age in all CXMDJ dogs. In the echocardiogram, one of eight of CXMDJ dogs showed a hyperechoic lesion in the left ventricular posterior wall at 5 months of age, but the rest had not by 6–7 months of age. The left ventricular function in the echocardiogram indicated no abnormality in all CXMDJ dogs by 6–7 months of age. Histopathology revealed myocardial fibrosis, especially in the left ventricular posterobasal wall, in three of eight CXMDJ dogs by 21 months of age. Conclusion Cardiac involvement in CXMDJ dogs is milder and has slower progression than that described in GRMD dogs. The distinct deep Q-waves have been ascribed to myocardial fibrosis in the posterobasal region of the left ventricle, but our data showed that they precede the lesion on echocardiogram and histopathology. These findings imply that studies of CXMDJ may reveal not only another causative mechanism of the deep Q-waves but also more information on the pathogenesis in the dystrophin-deficient heart.

Objectives This study was intended to compare the tissue chymase-like activity and angiotensin converting enzyme (ACE) activity in the right and left ventricles of a dog with congenital pulmonic stenosis (PS), with normal dogs, and to discuss the potential clinical implications of these findings. Animals, materials and methods Study subjects included a one-year-old Beagle dog with spontaneous PS and six clinically normal Beagles. Chymase-like and ACE activities were determined in all hearts by high pressure liquid chromatography. Results In the PS dog right ventricular (RV) chymase-like activity (49.79 nmol/min/g tissue) and left ventricular (LV) chymase-like activity (36.85 nmol/min/g tissue) were elevated vs normal Beagle dogs (mean ± standard deviation, RV: 20.17 ± 5.24 nmol/min/g, LV: 19.03 ± 3.27 nmol/min/g). Conclusions Activation of the tissue RAA system was detected in a dog with congenital PS. This interesting finding should be pursued with further studies to validate this result, and to explore whether pharmacological blockade of chymase, or the angiotensin II receptor, represents a useful strategy to prevent myocardial remodeling in this condition.

The purpose of this study was to evaluate the feasibility, safety, and efficacy of transcatheter closure in dogs with a congenital perimembranous ventricular septal defect (VSD) by using a detachable coil. No dogs showed any symptoms, and results of chest X-rays and ECGs were normal. The diameters of VSD ranged from 2 to 4 mm on echocardiogram. The defect was 2-2.5 mm from the aortic valve. A detachable coil (size 5 mm with 5 loops) designed for patent ductus arteriosus was delivered via the transarterial route. The device was successfully employed in all dogs. A minimal residual shunt was observed in all dogs even though Qp/Qs decreased. Hemolysis and a rate-dependent right-bundle branch block were observed in 1 dog, but there was no clinical significance. No major complication was noted. Pathologic examination after 1 year revealed that the coils were covered with tissue without significant damage to the His-Purkinje conduction system. In conclusion, transcatheter closure of a small perimembranous VSD with a detachable coil can be achieved without major complications or significant pathologic damage at the lesion site.

A primary cardiac fibrosarcoma in the right atrium of a 6-year-old Chihuahua dog is described. At necropsy, there was a firm, whitish and spherical mass in the right atrium. Histopathologically, the mass had moderate cellularity composed of spindle-shaped cells with scattered multinucleated giant cells. The tumor cells were arranged in interwoven bundles and sheets in the collagenous stroma. No metastases were observed. Ultrastructurally, the tumor cells mainly consisted of fibroblasts. Multinucleated giant cells did not have any certain organelles that would indicate a higher order of differentiation. Primary cardiac sarcomas in dogs are extremely rare.

A 10-month-old, female Holstein-Friesian cow with tetralogy of Fallot died during surgery for ameliorating pulmonary stenosis. Necropsy revealed no fracture of bones. Microscopically, fat emboli in the capillaries were detected in the brain, kidney, lung, adrenal gland and pituitary. In the kidney, many fat emboli were present in the glomeruli. No significant changes of the neurons were found throughout the brain, and perivascular hemorrhage and/or necrosis were rarely seen accompanying with fat emboli in the cerebral cortex. The trigger for fat embolism might be costectomy, and right-to-left shunt due to heart malformation might be attributed to crossed and systemic distribution of the fat emboli.

We examined the prevalence and characteristics of valvular regurgitation in 20 normal beagle dogs with no cardiac murmur by color Doppler echocardiography. The prevalence of pulmonary, mitral, aortic and tricuspid valvular regurgitation was 75%, 15%, 10%, and 0%, respectively. The peak flow velocity of pulmonary, mitral and aortic regurgitation was 57.1 +/- 18.5 cm/sec (mean +/- SD), 89.8 cm/sec (mean) and 96.5 cm/sec, respectively. The peak velocity of regurgitant flow was considered characteristically low, as the calculated pressure gradient derived from the modified Bernoulli equation (pressure gradient = 4 x velocity) was not as high as the normal pressure gradient existing across each valve. We consider that, in the evaluation of the characteristics of regurgitation in dogs, regurgitant signals having low peak velocity can be regarded as being physiological or trivial regurgitation.

Objective—To characterize structural changes in pulmonary vessels of dogs with dirofilariosis. Animals—8 dogs with dirofilariosis and 2 unaffected control dogs. Procedure—Pulmonary artery pressure was measured in affected dogs, and dogs then were euthanatized. Scanning electron microscopy was used to examine vascular corrosion casts of pulmonary vasculature. Tissue sections of pulmonary vasculature were evaluated by use of histologic examination. Results—Pulmonary artery pressure was higher in dogs with severely affected pulmonary vessels. In tissue sections, dilatation, as well as lesions in the tunica intima and proliferative lesions resulting in constriction or obstruction, were frequently observed in branches of the pulmonary artery. Numerous dilated bronchial arteries were observed around affected pulmonary arteries. Hyperplastic venous sphincters were observed in small pulmonary veins and venules. In corrosion casts, affected pulmonary lobar arteries had dilatation, pruning, abnormal tapering, constriction, and obstruction. In small arteries and arterioles, surface structures representing aneurisms and edema were seen. Bronchial arteries were well developed and extremely dilated, and they formed numerous anastomoses with pulmonary arteries at all levels, from the pulmonary trunk to peripheral vessels. Capillaries in the lungs were dilated with little structural change. Small pulmonary veins and venules had irregular annular constrictions that were caused by hyperplastic smooth muscle cells of venous sphincters. Conclusions and Clinical Relevance—Scanning electron microscopy of microvascular casts delineated links between the bronchial and pulmonary circulations in dogs with dirofilariosis. Results of scanning electron microscopy provided a structural explanation for the development of pulmonary circulatory disturbances and pulmonary hypertension in dogs affected by dirofilariosis. (Am J Vet Res 2002:63:1538–1544)

Semi-immobilization of a partial area of the ventral edge, lateral epicardium of the left auricle (ventrolateral of left auricle), by using quick adhesion glue induces moderate hypertrophy of myocytes with an average increase of 34% in cross-sectional area. Intercellular connective tissues increased, and cellular sizes varied markedly. The ultrastructure of immobilized (semi-immobilized) myocytes commonly exhibited degenerating features in myofibrils, various cytoplasmic organelles including mitochondrial cristae and sarcoplasmic reticulum (SR) were disrupted, and T-tubules disappeared. Z-line streaming and widening (hypertrophic Z-line, rod bodies) and increase of metabolic particle deposition are typical phenomena in addition to intercalated disc (Id) disorganization. The results suggest that semi-immobilization of the auricle induces hypertrophy of myocytes in association with degeneration and disruption of myofibrils and other cytoplasmic organelles, and an increase of intercellular connective tissues, rather than increase of myofibril mass. This is the first study to immobilize only a part of the heart rather than the whole animal. Our results using artificial immobilization of cardiac myocytes were extremely significant since the structural alterations obtained were similar to that observed in cardiomyopathies. This suggests that myocytes progressing to heart failure are also subjected to inhibition of movement. Therefore, this experiment may prove very useful as a model for studying the functional effect of heart failure observed in cardiomyopathy.

Two 2-month-old kittens presented with a loud cardiac murmur. One cat showed severe signs of heart failure such as respiratory effort and exercise intolerance. Echocardiography revealed left ventricular concentric hypertrophy and severe left ventricular outflow obstruction. They died at 5 and 12 months of age, respectively. Necropsy and histopathology confirmed hypertrophic cardiomyopathy.

In this study, we evaluated methods of determining the velocity patterns of pulmonary venous flow (PVF) in dogs and then investigated the relationship of the patterns to cardiac functions in heartworm disease (HD) by transthoracic echocardiography (TTE). The results revealed that there was a good correlation between PVF patterns determined by transesophageal echocardiography (TEE) and TTE in animals lying on their left sides. The measurement of S and D wave velocities (PVS and PVD) by TTE was shown to allow clinical determination of the velocity patterns of PVF in dogs. The HD groups showed significant increases in PVS and PVD, and S and D wave time-velocity integrals (S-TVI and D-TVI) of the right cranial lobe PVF, when compared with the normal group, as determined by TTE (P

The circadian variation of urinary N-acetyl-beta-D-glucosaminidase (NAG, EC 3.2.1.30) and gamma-glutamyl transpeptidase (gamma-GTP, EC 2.3.2.2) was evaluated in cats. Urine and blood were collected at 4-hr intervals from adult cats (3 males, 9 females) weighing between 2.6 and 5.0 kg. There was no circadian variation in the urine volume, creatinine clearance, creatinine excretion, NAG excretion or gamma-GTP excretion. The average NAG and gamma-GTP indices in the 4-hr urine were similar to those for the 24-hr urine. However, the variance for the 4-hr urine samples was higher than that of 24-hr urine. In conclusion, although 4-hr urine samples can be used to estimate 24-hr urinary enzyme excretion, short-term spot urine samples may cause increased variation in the enzyme index.

We studied the excretory variation of urinary glycyl-prolyl dipeptidyl aminopeptidase ( GP-DAP, EC 3.4.14.5) in dogs. Adult domestic mongrel dogs (seven males and nine females, 7·5 to 13 kg bodyweight) Which were considered to be healthy by laboratory tests were used. Urine and blood samples were obtained every four hours. Urine volume was measured for each sample and urine GP-DAP activity, and creatinine levels Were determined. Creatinine clearance, creatinine excretion, GP-DAP activity and GP-DAP index ( GP-DAP /Cr ratio) did not show any significant variation between the time periods. However, urine volume and urinary GP-DAP excretion significantly increased from 8:00 am to 12:00 pm. The GP-DAP index in spot urine samples showed low correlation with 24 hour GP-DAP excretion. In addition, a sex difference was observed in GP-DAP excretion. In conclusion, urinary GP-DAP excretion showed a circadian variation and sex difference. Therefore, GP-DAP in spot urine is not of use for the detection of renal disorders, and the 24-hour excretion value of GP-DAP should be determined.