动物黑色素细胞及其相关性状形成机制的研究进展

黑色素细胞是合成黑色素的细胞,由其前体细胞黑色素母细胞分化而来,胚胎期黑色素母细胞的形成有两次,一次是具有黑色素细胞特性的神经嵴细胞沿背外侧迁移而形成,另一次是由沿腹侧迁移的神经嵴细胞亚细胞雪旺氏细胞前体（Schwann cell precursors,SCPs）受到某种信号诱导后形成,这是皮肤中黑色素细胞形成的主要方式。黑色素细胞的形成与动物毛发颜色及其他重要经济性状密切相关,其形成的增多或减少,异位形成或异位侵袭均可能导致相应的疾病,但脊椎动物中具有典型黑色素细胞异位形成特征的乌骨鸡却繁衍至今,而且是重要的食用和药用经济动物。探索黑色素细胞的形成及其对相关性状的影响不但能为动物经济性状育种提供相关理论基础,也可为相关疾病的治疗提供理论依据。作者从黑色素细胞的来源及其形成过程中参与的信号因子来探讨其形成机制,并对黑色素细胞相关性状的形成机制尤其是乌质性状进行综述。     

Ectopic Tissue Consisting of a Mixture of Glandular Gastric,Intestinal, and Exocrine Pancreatic Tissue in the Forestomach of a Rat

The development of ectopic gastric, intestinal, or pancreatic tissue in the gastrointestinal tract is extremely rare in rats, although it is fairly common in humans. In this report, we describe an unusual case in which a mixture of different types of ectopic tissue was found in the forestomach of a rat. A solitary white nodular/polypoid structure, which measured 5 mm in size, was detected on the luminal surface of the greater curvature of the forestomach in an 8-week-old female Crl:CD(SD) rat. A histological examination revealed that the lesion contained ectopic glandular gastric tissue, including gastric surface mucous cells, parietal cells, and pyloric gland cells, which was confirmed by immunohistochemistry. Moreover, the lesion also contained villin-positive columnar intestinal absorptive cells and chymotrypsin-positive pancreatic exocrine tissue. To the best of our knowledge, this is the first study to detect a mixture of ectopic glandular gastric, intestinal, and exocrine pancreatic tissue in a rat.     

PERCUTANEOUS ULTRASOUND-GUIDED PYELOGRAPHY AIDED DIAGNOSIS OF ECTOPIC URETER AND HYDRONEPHROSIS IN A 3-WEEK-OLD FILLY

Ultrasound-guided percutaneous pyelography has previously been used in dogs to diagnose ectopic ureter. To the authors' knowledge its use has never been reported in the horse. This paper reports the technique used in a three-week-old filly with a suspected ectopic ureter. Pyelography can be performed under sedation and is a relatively simple, safe procedure. The technique enables assessment of individual renal function through collection and analysis of urine from each renal pelvis.     

URETERAL DUPLICATION IN A DOG

A male neutered dog of unknown age had recurrent urinary tract infection and caudal abdominal pain. Using sonography, large dilated tubular structure filled with echogenic fluid was seen extending from the left kidney to the level of the bladder neck. In an excretory urogram there was left hydronephrosis with a normal ureter. Computed tomographic evaluation of the abdomen confirmed a large tubular structure extending from the kidney with a blind ending caudally. The left kidney, ureter, and associated tubular structure were surgically removed. No connection was found between the tubular structure and the ureter. Gross evaluation and histopathologic evaluation confirmed the tubular structure to be a ureter, consistent with a diagnosis of ureteral duplication.     

Hepatic carcinoid, hypercortisolism and hypokalaemia in a dog

A German Shepherd dog was diagnosed with periodic myopathy secondary to persistent hypokalaemia. Hormone analysis revealed excess cortisol secretion. A neuroendocrine carcinoma, thought to be a primary hepatic carcinoid, was detected in the liver. Ectopic adrenocorticotrophin hormone secretion was suspected as the cause of hypercortisolism and hypokalaemia, although this could not be confirmed by immunohistochemical staining.     

蒺藜苜蓿膜联蛋白MtANN2基因的表达模式及盐胁迫下的功能分析

膜联蛋白（annexins）是一类进化保守的多基因家族蛋白,它们广泛存在于真核生物中,能通过Ca²⁺与膜磷脂的结合参与胁迫相关的多种生物学过程。早期对膜联蛋白的研究多集中于脊椎动物,对植物膜联蛋白的认识开始于番茄。关于豆科植物尤其是牧草中膜联蛋白的研究还鲜有报道。本研究分析了蒺藜苜蓿膜联蛋白与饲草紫花苜蓿同源蛋白的进化关系,研究了蒺藜苜蓿膜联蛋白基因MtANN2的表达模式,进一步利用拟南芥同源基因的突变体阐明了MtANN2在根系发育和盐胁迫中的功能。RT-qPCR结果显示,MtANN2在根中高丰度表达,且表达水平受NaCl诱导。RNA原位杂交表明MtANN2特异表达于幼苗侧根原基。拟南芥同源基因AtANN2的T-DNA插入突变体植株弱小、侧根数少、根鲜重低,且对盐（100 mmol·L^-1）处理的敏感性显著高于野生型。超表达MtANN2于atann2后转基因植株的侧根数介于野生型与突变体之间,根鲜重接近野生型,表明MtANN2能在一定程度上互补该突变体的表型缺陷。在盐处理下,该转基因株系的发芽率和长势均恢复到类似野生型的水平。以上结果从分子水平上表明,蒺藜苜蓿膜联蛋白MtANN2参与植物根系生长及盐胁迫响应,高水平表达该基因能够改善植物的耐盐性。本研究为紫花苜蓿耐盐分子育种提供了备选基因。     

IMAGING DIAGNOSIS—DUODENAL DIVERTICULUM IN A DOG

A young female Boxer had a history of chronic soft stool. Survey abdominal radiographs were unremarkable. A duodenal diverticulum was identified in abdominal ultrasound and barium upper-gastrointestinal contrast examinations. Before surgery a ^99mTc-pertechnetate study was performed to evaluate for ectopic gastric mucosa in the duodenal diverticulum. Focal abnormal increased radioactivity was identified in the right caudal abdominal quadrant. The diverticulum was excised. Upon histopathologic examination of the duodenal diverticulum, ectopic gastric mucosa was not identified but ectopic pancreatic tissue was found. Mild eosinophilic inflammation within the diverticulum was suspected to be the cause of the mild ^99mTc uptake seen in this dog.     

异位发酵床垫料的直剪切及压缩试验研究

为研究不同含水率的条件下异位发酵床垫料:抗剪强度、黏聚力、内摩擦系数、压缩载荷的变化规律.本研究采用土壤力学试验方法,测定垫料五种不同含水率的相关参数.结果表明:当垫料含水率为29.22％～36.13％时,抗剪强度、内摩擦角系数会随着含水率的增大而增大;当含水率为45.55％～61.11％时,抗剪强度、内摩擦角系数会随...     

EVALUATION OF THE URETER AND URETEROVESICULAR JUNCTION USING HELICAL COMPUTED TOMOGRAPHIC EXCRETORY UROGRAPHY IN HEALTHY DOGS

Abdominal computed tomography (CT) using a protocol designed for evaluation of the ureters was performed on six normal purpose-bred research dogs. After noncontrast CT, a postcontrast scan was performed 3 min post midpoint of injection of 400 mgI/kg body weight of diatrizoate meglumine/sodium. Ureteral and ureterovesicular junction anatomy were readily assessed with minimal patient preparation. The ureters were similar in size to reported values and the renal pelvis, ureter, and ureterovesicular junction were easily identified on both noncontrast and contrast-enhanced scans. There was a significant relationship between bladder volume and interureterovesicular junction distance but not between bladder volume and ureterovesicular junction to internal urethral orifice distance. A reliable bony landmark for the identification of the internal urethral orifice could not be determined. The results of this preliminary study of normal anatomy should facilitate the clinical use of CT in the evaluation of ureteral disease (e.g., ureteral ectopia).     

Conjunctival dacryops in two golden retrievers

Two 5-month-old golden retriever dogs were referred for the evaluation of a mass arising from the left ventrolateral conjunctiva of the lower eyelid. The masses were externally located, deemed to be cystic in nature, and were surgically removed, and in one case, 0.15 mL of clear fluid was collected. Cytological examination of the aspirated fluid revealed proteinaceous, basophilic amorphous material, and few epithelial cells with foamy cytoplasm and small nuclei. No micro-organisms were detected. Histological examination of the cysts showed a wall composed of single to double cell layers. The cells were cuboidal to flattened, nonciliated, lined with mild submucosal connective tissues and slight inflammation composed of lymphocytes, plasma cells, and rare macrophages. In some areas, lobules of acinar glandular tissue were observed. To the authors' knowledge, this is the first case report of conjunctival dacryops in dogs. The complete surgical removal of the cysts was curative in both cases.