Young Fischer 344 rats are more susceptible than adults to copper-induced liver injury.

Autologous mesenchymal stem cells (MSCs) have been used as a potential cell-based therapy in various animal and human diseases. Their differentiation capacity makes them useful as a novel strategy in the treatment of tissue injury in which the healing process is compromised or delayed. In horses, bone healing is slow, taking a minimum of 6-12 months. The osteogenic capacity of equine bone marrow and muscle MSCs mixed with fibrin glue or phosphate-buffered saline (PBS) as a scaffold is assessed. Bone production by the following groups was compared: Group 1, bone marrow (BM) MSCs in fibrin glue; Group 2, muscle (M) MSCs in fibrin glue; Group 3, BM MSCs in PBS; Group 4, M MSCs in PBS and as a control; Group 5, fibrin glue without cells. BM and M MSCs underwent osteogenic stimulation for 48 h prior to being injected intramuscularly into nude mice. After 4 weeks, the mice were killed and muscle samples were collected and evaluated for bone formation and mineralization by using radiology, histochemistry and immunohistochemistry. Positive bone formation and mineralization were confirmed in Group 1 in nude mice based on calcium deposition and the presence of osteocalcin and collagen type I; in addition, a radiopaque area was observed on radiographs. However, no evidence of mineralization or bone formation was observed in Groups 2-5. In this animal model, equine BM MSCs mixed with fibrin glue showed better osteogenic differentiation capacity compared with BM MSCs in PBS and M MSCs in either carrier.

Summary A 15‐year‐old Quarter Horse mare was examined for significant and progressive lameness in the right front limb. On physical examination, muscle atrophy over the scapular and pectoral regions were noted. A pain response was elicited on palpation of the scapulohumeral joint. No other abnormalities were noted on examination of the limb. Diagnostic nerve blocks ruled out a source of lameness in the distal limb. Arthrocentesis of the scapulohumeral joint was performed and results were within normal limits. Radiographs of the right scapulohumeral joint revealed an extensive, aggressive bone lesion in the proximal humerus, suspected to be an osteosarcoma. After a course of nonsteroidal anti‐inflammatory therapy, minimal improvement to the lameness was noted. The owner elected to subject the horse to euthanasia due to the lack of significant response to treatment. Post mortem radiographic and histological examinations determined a definitive diagnosis of an osteosarcoma in the proximal humerus.

Recent advances in molecular biology have made possible the identification of

The epidemiological and clinicopathological features of canine mammary tumors may provide valuable information to facilitate analysis of the behavior of the disease and represent a potential tool for the study of breast cancer in women. The aim of this study was to associate the histological features of canine mammary tumors with potential risk factors and survival. One hundred and seventy-eight mammary tumors were collected from 80 female dogs. The statistical analyses consisted of a series of univariate studies and frequencies of the different study variables, such as a bivariate analysis with the Chi squared test (χ2), a relative risk and Kaplan Meier survival analysis, and a multiple correspondence analysis was used to correlate the tumor’s biological behavior with the dogs’ breed. Most patients were older than 8 years and had at least one malignant tumor, which was usually solitary and measured more than 6 cm; these patients had poor survival. The most frequent tumors were a complex adenoma, benign mixed tumor, carcinoma complex and mixed type carcinoma. The most commonly affected breeds were Poodle, Cocker Spaniel and Dachshund, and the breeds at the highest risk of tumor development were Cocker Spaniel, Labrador Retriever and German Shepherd. Overall, the data indicated that mammary tumors in dogs mainly affected older females with malignant tumors and that there were high mortality and short-term survival rates. However, the most commonly affected breeds were not necessarily the most susceptible. Our data do not support the hypothesis of an increased risk of canine mammary tumors in nulliparous female dogs.