IMAGING DIAGNOSIS—AN ATYPICAL PRESENTATION OF DIFFUSE IDIOPATHIC SKELETAL HYPEROSTOSIS (DISH) IN A DOG

A 10‐year‐old female spayed Dalmatian was evaluated for progressive cervical scoliosis and stiffness. This imaging report describes the imaging and postmortem findings for this patient. A diagnosis of an atypical manifestation of diffuse idiopathic skeletal hyperostosis (DISH) was made based on imaging and additional diagnostics. This report serves to increase awareness of DISH in the veterinary community, as well as to describe a unique presentation of the disease with atypical lesion distribution and severity. In addition, this report contrasts the pathophysiology and imaging characteristics of DISH with spondylosis deformans, which can appear comparable radiographically.     

鹿茸再生干细胞成骨诱导(微粒体)培养体系的建立

针对鹿茸再生活体研究周期长、耗资大、对动物损伤大等问题,利用在培养液中加入TGF-β1、地塞米松、抗坏血酸、β-磷酸甘油等对鹿茸再生干细胞进行体外诱导,成功建立了一种鹿茸再生干细胞体外诱导成骨的培养体系,模拟了鹿茸软骨内骨化的生长过程。     

IDENTIFICATION OF AN OSSICLE ASSOCIATED WITH THE PALMAR ASPECT OF THE CARPUS IN THE HORSE

An ossicle associated with the palmar aspect of the carpus is described in five horses. The size of the ossicle varied from 3 x 4 mm to approximately 12 x 10 mm. The ossicles were located at the junction of the proximal and distal rows of carpal bones, between the palmaromedial aspect of the fourth carpal bone and the ulnar carpal bone. In 3 horses they were bilateral, in one horse unilateral, and only one limb was examined in the remaining horse. In all horses it was an incidental finding and not regarded to be a pathologic entity.     

Spinal dural ossification causing neurological signs in a cat

A six-year-old Ragdoll cat underwent examination due to a six-month history of slowly progressive gait abnormalities. The cat presented with an ambulatory tetraparesis with a neurological examination indicating a C1-T2 myelopathy. Radiographs of the spine showed a radiopaque irregular line ventrally in the vertebral canal dorsal to vertebral bodies C3-C5. In this area, magnetic resonance imaging revealed an intradural extramedullary/extradural lesion compressing the spinal cord. The spinal cord was surgically decompressed. The cause of the spinal cord compression was dural ossification, a diagnosis confirmed by histopathological examination of the surgically dissected sample of dura mater. The cat gradually improved after the procedure and was ambulating better than prior to the surgery. The cat’s locomotion later worsened again due to ossified plaques in the dura causing spinal cord compression on the same cervical area as before. Oral prednisolone treatment provided temporary remission. Ten months after surgery, the cat was euthanized due to severe worsening of gait abnormalities, non-ambulatory tetraparesis. Necropsy confirmed spinal cord compression and secondary degenerative changes in the spinal cord on cervical and lumbar areas caused by dural ossification. To our knowledge, this is the first report of spinal dural ossification in a cat. The reported cat showed neurological signs associated with these dural changes. Dural ossification should be considered in the differential diagnosis of compressive spinal cord disorders in cats.     

Metabolic Challenges and Early Bone Development

Lameness is the phenotypic expression of a wide variety of genetic, conformational, nutritional, toxic, and infectious conditions. Poultry selected for rapid growth are susceptible to lameness, and it can be a significant source of mortality in heavy birds. Genetic selection has been successful in providing annual improvements in meat poultry productivity; however, some support systems, such as the cardiovascular and skeletal systems, have not kept up with the increase in body mass, making birds increasingly susceptible to compromise or failure of these systems. Breeders have been selecting for robust support systems in addition to increased productivity, but meat birds are still challenged with keeping structural and supply organs synchronized with the growth of demand tissues such as muscle. The structural system of the bird is comprised of bone, cartilage, ligaments, tendons, and the connective tissue of skin and other organs. Healthy bone growth can be disrupted by developmental, nutritional, environmental, or infectious conditions, with bone problems often being associated with more than one of these causes. A review of recent reports on bone formation and the role of trace minerals in bone development and repair indicate that availability of Zn, Cu, and Mn should be considered by nutritionists who want to enhance the resilience of bone, cartilage, and other structural tissues in their birds.     

Primary isolated osteoma cutis causing eyelid deformation and strabismus in a dog

Osteoma cutis describes bone formation in skin and is well documented in the medical literature, but veterinary reports are few. We report a single case of a juvenile samoyed that was referred for assessment of a superior eyelid anomaly. Exploratory surgery and histopathology revealed the presence of mature, lamellar bone within the superior eyelid. The histologic appearance was consistent with primary osteoma cutis. The presence of the ossification within the deep dermis of the eyelid was associated with an abnormal conformation causing trichiasis, keratitis and dorsal strabismus. Identification of the osseous lesion during surgery and its removal was curative with no recurrence of disease during the 32 month follow‐up period.     

INCOMPLETE OSSIFICATION OF THE ATLAS IN DOGS WITH CERVICAL SIGNS

Osseous defects affecting the atlas were identified in computed tomography and magnetic resonance images of five dogs with cervical signs including pain, ataxia, tetraparesis, or tetraplegia. Osseous defects corresponded to normal positions of sutures between the halves of the neural arch and the intercentrum, and were compatible with incomplete ossification. Alignment between the portions of the atlas appeared relatively normal in four dogs. In these dogs the bone edges were smooth and rounded with a superficial layer of relatively compact cortical bone. Displacement compatible with unstable fracture was evident in one dog. Concurrent atlantoaxial subluxation, with dorsal displacement of the axis relative to the atlas, was evident in four dogs. Three dogs received surgical treatment and two dogs were treated conservatively. All dogs improved clinically. Incomplete ossification of the atlas, which may be associated with atlantoaxial subluxation, should be considered in the differential diagnosis of dogs with clinical signs localized to the cranial cervical region.     

唇䱻twist1和twist2基因克隆及其在肌间刺骨化过程中的表达

在脊椎动物中存在着2种twist基因,即twist1和twist2,二者对骨骼的发育具有调控作用。为探究唇?twist1和twist2与肌间刺骨化的相关性,实验克隆得到了唇?twist1和twist2基因cDNA序列。氨基酸序列比对结果显示,唇?TWIST1和TWIST2与其他鱼类保守性较高,都具有螺旋-环-螺旋(HLH)结构域和色氨酸-精氨酸(WR)结构域。系统进化树分析表明,唇?TWIST1和TWIST2与斑马鱼亲缘关系最为接近。通过荧光定量PCR检测发现唇?twist1和twist2基因在所有被检测的组织中均有表达,twist1在脑中的表达量最高,心脏中次之,在脾脏中表达量最低。twist2在皮肤和鳃中的表达量较高,在脾脏中的表达量最低。此外,twist1和twist2基因的表达量在肌间刺骨化的4个关键阶段发生显著变化。研究表明,twist基因与肌间刺骨化有一定的相关性。本研究首次在经济鱼类中克隆得到了twist基因,并揭示了twist基因与肌间刺骨化的相关性。研究结果将为进一步调查鱼类twist基因功能以及肌间刺形成的分子机制提供基础数据。     

A SKELETAL OSSIFICATION INDEX FOR NEONATAL FOALS

A skeletal ossification index (SOI) was devised to standardize the radiographic evaluation of the carpal and tarsal regions of newborn foals (less than two weeks of age). This index was based on two radiographic views of a carpus and a tarsus. Four grades of cuboidal bone ossification were discerned: Grade 1 foals had some cuboidal bones with no ossification; Grade 2 was assigned when all cuboidal bones had radiographic evidence of some ossification; in Grade 3 the bones were small and round; in Grade 4 the cuboidal bones were shaped like the adult counterparts. Radiographs were taken of 24 neonatal foals of various gestational ages (range, 297–374 days). The relationships between the SOI and two measures of newborn foal developmental maturity, gestationai age and body weight, were assessed. There was no relationship between the sex of the foal and the SOI, but there was a relationship between the SOI and the gestational age (one-tailed Spearman's rank correlation coefficient, r = 0.748) and between the SOI and body weight (r = 0.77) for the 24 foals. For the ten foals with gestational ages less than 320 days, the relationship between body weight and the SOI was significant (r = 0.953), but the relationship between gestational age and the SOI was not significant (r = 0.605). The degree of ossification of the bones of neonatal foals that are born prematurely (< 320 days of gestation) or are "small-for-gestational age" at birth may be incomplete, and we suggest that radiographs of these regions should be made to assess ossification in foals in these two high risk groups.