Tetsuro Ito

Identification of Cancer Stem Cells Derived From a Canine Lung Adenocarcinoma Cell Line

Accumulating evidence supporting the cancer stem cell (CSC) hypothesis is based on the finding that tumors contain a small population of self-renewing cells that generate differentiated progeny and thereby contribute to tumor heterogeneity. CSCs are reported to exist in several human cancers, yet only a few reports demonstrate the existence of CSCs in primary lung cancer in dogs. In this study, the authors established a cancer cell line derived from a canine primary lung adenocarcinoma and identified a side population (SP) of cells that displayed drug-resistant features. To confirm the characteristics of these SP cells, the authors investigated the tumorigenicity of the cells in vivo by using a nude mouse xenograft model. Only 100 SP cells were able to give rise to new tumors, giving a 10-fold enrichment over the main population (MP) of cells, suggesting that these cells have the cancer-initiating ability of CSCs. Further studies characterizing CSCs in canine lung adenocarcinoma might contribute to the elucidation of the mechanisms of tumorigenesis and to the establishment of novel therapeutic strategies.

Infective endocarditis of the aortic valve in a Border collie dog with patent ductus arteriosus

Infective endocarditis (IE) in dogs with cardiac shunts has not been reported previously. However, we encountered a dog with concurrent patent ductus arteriosus (PDA) and IE. The dog was a 1-year-old, 13.9-kg female Border collie and presented with anorexia, weight loss, pyrexia (40.4°C) and lameness. A continuous murmur with maximal intensity over the left heart base (Levine 5/6) was detected on auscultation. Echocardiography revealed a PDA and severe aortic stenosis (AS) caused by aortic-valve vegetative lesions. Corynebacterium spp. and Bacillus subtilis were isolated from blood cultures. The dog responded to aggressive antibiotic therapy, and the PDA was subsequently surgically corrected. After a series of treatments, the dog showed long-term improvement in clinical status.

Dynamic left ventricular outflow tract obstruction secondary to hypovolemia in a German Shepard dog with splenic hemangiosarcoma

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.

Peripheral pulmonary artery stenosis in three cats

Case 1 involved a 4-month-old intact male Somali cat in which peripheral pulmonary artery stenosis (PPS) was recognized after a cardiac murmur remained following patent ductus arteriosus ligation. Case 2, which involved a 1-year-old neutered male Norwegian Forest cat, and Case 3, which involved a 6-month-old intact female American Curl cat, were referred, because of cardiac murmurs. Grades III to IV/VI systolic heart murmurs were auscultated at the left heart base in all 3 cats. All cases showed bilateral pulmonary artery stenosis, although there were no associated clinical signs. In Cases 1 and 2, the pressure gradient through the stenosis decreased after treatment with atenolol.

Primary Lung Carcinoma with Paraneoplastic Leukocytosis in a Dog

In human lung cancers, marked leukocytosis, especially with neutrophilia and monocytosis, has been reported as a paraneoplastic syndrome. In dogs, several reports have been published on paraneoplastic leukocytosis. In this case, various examinations were conducted on a dog with extreme neutrophilic leukocytosis diagnosed via a blood test at first admission. A huge pulmonary mass was detected, which was surgically removed. The tumor was diagnosed as papillary adenocarcinoma of the lung by histopathology. The number of neutrophils recovered to normal after surgery, and the dog was diagnosed as paraneoplastic syndrome due to lung cancer. Key word:dog, leukocytosis, lung cancer, paraneoplastic syndrome 1)Sato Animal Hospital, 1-14 Miyashitachou, Ichinoseki, Iwate 021-0013, Japan 2)School of Veterinary Medicine, Azabu University, 1-17-71 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5201, Japan 3)Veterinary Teaching Hospital, Azabu University, 1-17-71 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5201, Japan 4)Yamada Animal Hospital, 2-1, Koorikitanomachi, Neyagawa, Osaka 572-0080, Japan Corresponding author:Takuo Shida Telephone:042-754-7111 Facsimile:042-769-2418 Email address:shida@azabu-u.ac.jp Received:May 27, 2012 / Accepted:September 12, 2012 Note J Jpn Vet Cancer Soc, 3(2) −21− were all within normal ranges. According to these results, we surmised that the elevated BUN level was prerenal secondary to cardiac insufficiency. Based on these clinical data, the cause of the cough and the neutrophilia were considered to possibly be related to the thoracic mass. In order to improve the cough, thoracotomy was performed. The patient underwent surgery through the intercostal approach on the 15th day after first admission. The 5th rib of the patient was removed due to the large size of the mass. The mass involved the left caudal lung lobe and adhered to the pleura of the mediastinum and diaphragm. The pericardium was not involved in the mass. Blunt dissection of the mass from the pleura of the mediastinum caused some bleeding. After blunt dissection from the adhered sites, the left lung lobe was totally removed with the mass. Swelling of the tracheobronchial lymph nodes was not observed. The patient recovered from surgery without any events and showed good healthy conditions. The WBC count decreased to the normal range 2 weeks after surgery(Table 3)and was normal for 21 weeks after surgery. The patient’s cough disappeared after surgery, and the respiratory function of the patient was recovered. Furthermore, cardiac function was maintained well with the simultaneous administration of digoxin and an angiotensin converting enzyme inhibitor for cardiac insufficiency. However, cardiac function worsened, and 4 months after surgery, the patient had an increased BUN level. The patient showed collapse/syncope due to cardiac failure and died 5 months after surgery. Autopsy was not permitted by the client. Histopathological examination of the pulmonary mass revealed that the tissue consisted of multiple neoplastic foci divided by various amounts of fibrous septa. The neoplastic foci were characterized by papillary or glandular structures that were lined by cuboid to cylindroid epithelial cells. Some tumor cells showed a goblet-cell appearance, while some had cilia on their cell surface. These proliferating neoplastic cells showed moderate cellular atypia, and the mitotic figure index was 2-3 per high-power magnification(×400)field. The tumor cells invaded the lymph vessels of the surrounding tissues. Multifocal necrotic areas were also observed within the neoplastic foci. In the interstitial areas, there were moderate infiltrations of lymphocytes and macrophages, deposition of calcium, and occasional ossification. The pleurae were Fig. 1.Thoracic radiography(ventrodorsal view)revealed a large mass in the left caudal lung area that compressed and shifted the enlarged heart to the right. Fig. 2.Numerous neutrophils were observed in the blood smear specimen (×100).