固醇调控元件结合蛋白及其对乳脂合成的调节作用

固醇调控元件结合蛋白(SREBPs)广泛分布于哺乳动物的肝脏、白色脂肪组织、肾上腺、乳腺组织等处,与乳脂的合成关系密切,它可以调控脂类合成相关酶基因的表达.通过与日的酶基因启动子中的固醇调节元件(SRE)结合激活目的基因转录,从而调控脂类合成.SREBPs在自身合成过程中会在转录、翻译及翻译后水平上受到多重因素的调控.本文从SREBPs的结构功能、组织分布、合成调节及其与乳脂合成的关系等方面进行了综述.     

固醇调节元件结合蛋白(SREBPs)调控牛科物种脂合成的研究进展*

固醇调节元件结合蛋白(Sterol Regulatory Elemental Binding Protein ,SREBPs)是细胞核内调控脂代谢的重要转录因子,其在细胞核内通过结合下游靶基因调控区的顺式作用元件来参与转录过程,进而调控脂代谢,包括调控体脂的沉积和乳脂的合成。本文综述了SREBPs的结构与功能、SREBPs参与的生物学路径及SREBP1参与牛科物种体脂沉积和乳脂合成的研究进展,旨在为牛SREBPs的深入研究提供参考。     

SREBPs对脂肪代谢的调控及其应用前景

固醇调节元件结合蛋白(SREBPs),是主要的调节胆固醇、脂肪酸及三酰甘油(TG)生物合成的转录因子,参与调控脂肪合成和吸收关键基因的表达。试验概括SREBPs的结构及其受胰岛素和维生素A调控的过程,并对当前SREBPs功能抑制的研究进行讨论。结果表明,SREBPs的抑制可成为治疗II型糖尿病、胰岛素耐受性、脂肪肝及动脉硬化(AS)等一系列代谢疾病的新靶点。     

Insig-SCAP-SREBP转运体系的研究进展

固醇调节元件结合蛋白SREBPs(sterol regulatorv element bingding proteins)是真核细胞内调节脂质合成的关键核转录因子。新合成的 SREBPs是一种没有活性的前体蛋白,通过两个跨膜α-螺旋结合在内质网上,必须由内质网转运到高尔基体后,才能加工成有活性转录因子——核     

固醇调控元件结合蛋白在胆固醇代谢中作用机制的研究进展

固醇调控元件结合蛋白(SREBPs)可以激活与乳脂合成密切相关的胆固醇等相关基因的表达。本文综述了SREBP在胆固醇代谢中的作用,初步构建了胆固醇-SREBP系统模型,以阐明细胞内胆固醇平衡调节的机理及其对乳脂合成代谢的意义。     

基础测绘在数字城市建设中的地位及其应用

基础测绘是数字城市框架和核心的基础系统工程，基础测绘为数字城市提供基础数据集，本文叙述了基础测绘和数字城市的重要作用，并叙述了基础测绘与数字成熟的共同点和差异性，提出构建数字空间数据基础框架，为建立数字城市服务。     

叶尔羌高原鳅三种同工酶的组织差异性研究

为了探究叶尔羌高原鳅同工酶表达的组织差异性和基因位点表达特征,试验采用不连续聚丙烯酰胺凝胶电泳技术对养殖和野生个体的心脏、肌肉、肝脏和肾脏4种组织器官的乳酸脱氢酶(LDH)、酯酶(EST)和苹果酸脱氢酶(MDH)进行分离、分析。结果表明:叶尔羌高原鳅LDH由2个基因位点编码,4种组织器官中共检测到3条酶带,组织差异性不明显;EST由3个基因位点编码,4种组织器官中共检测到7条酶带,其中EST-1a和EST-3b为各组织器官共有酶带,具有明显的组织差异性;MDH的S-MDH和M-MDH型同工酶在各组织器官中均有表达,4种组织器官中共检测到5条酶带,但酶带分布具有明显的组织差异性。根据酶谱特征对其种质鉴定进行了分析发现,叶尔羌高原鳅同工酶具有自属的一套同工酶系统特征。     

上市猪肌肉、脂肪组织间物质沉积与相关基因表达关系的研究

分析肌肉、脂肪组织中物质沉积相关基因表达的空间差异性与组织间物质沉积的关系。以180日龄上市商品猪为试验动物,通过相对定量RT-PCR的方法研究背最长肌、背部皮下脂肪和肾周脂肪中GH-R、leptin的基因表达状况。GH-R mRNA丰度在任意两组织间差异极显著,背最长肌中最少、背部皮下脂肪居中,肾周脂中最高;leptin mRNA丰度在背部皮下脂肪与肾周脂间无差异,没有检测到leptin在背最长肌中的表达;GH-R表达具有空间差异性,这种差异可能与组织生长代谢、物质沉积密切相关。     

影响畜禽矿物质利用的抗营养因子

文章叙述了植酸、棉酚、单宁、硫代葡萄糖甙、草酸、粗纤维这些抗营养因子对动物体在矿物质吸收中的影响,为今后科学组织畜牧业生产提供参考。     

我国与新加坡及国际食品法典委员会(CAC)牛类产品兽药残留限量标准比较研究

为了对我国与新加坡及国际食品法典委员会(CAC)兽药残留标准进行比较,系统分析差异性,并基于标准差异性进行政策建议研究,结合我国动物性食品生产实际,在兽药残留标准方面提出更加科学合理的实用性建议和提供依据,笔者从兽药种类、残留具体食品(靶组织)、残留限量值三个方面采用系统比较的方法分析了我国与新加坡及CAC在牛类产品兽药最大残留限量标准上的异同。结果表明:我国牛类产品兽药最大残留限量与新加坡及CAC相比存在靶组织规定不够全面、一些限量值不尽合理和不科学等问题。     

A case of otitis in a domestic cat

A case of otitis media and interna in a domestic cat is described in which granulation tissue extended into the external ear canal. An unusual histological feature was the presence of mucous glands within the granulation tissue. The possible origin of these glands and a differential diagnosis of this condition is discussed.     

Polypoid cystitis as a cause of haematuria in a pony mare

A 15-year-old pony mare was presented for investigation of haematuria of 2 weeks' duration. On cystoscopy, multiple small pedunculated soft tissue structures were observed on the bladder mucosa. Histopathological analysis of the masses was consistent with chronic polypoid cystitis. The polypoid lesions and associated haematuria resolved following prolonged antibiotic treatment. Polypoid cystitis has not previously been described in horses. This condition should be considered a differential for haematuria, requiring cystoscopy and biopsy to confirm a diagnosis.     

Characterization of a sterile soft-tissue inflammation model in Thoroughbred horses

This paper describes the use of subcutaneously-placed tissue chambers as a sterile soft-tissue inflammation model in Thoroughbred horses. Acute, nonimmune inflammation was initiated by injecting a sterile lambda carrageenan solution into a tissue chamber. This model was used to study the temporal changes in oxygen and carbon dioxide tensions, pH, bicarbonate, protein, albumin, prostaglandin E₂ (PGE₂) and leukotriene B₄ (LTB₄) concentrations, cell counts and differential counts in tissue fluid from inflamed tissue chambers and control chambers. Skin temperatures over control and inflamed chambers were also compared. Carrageenan-induced inflammation resulted in significant increases in tissue-fluid carbon dioxide tension, leucocyte count, albumin, and PGE₂ and LTB₄ concentrations. It also resulted in a significant decrease in tissue fluid pH and HCO₃- concentration. Inflammation did not result in significant changes in tissue-fluid protein concentration, differential cell counts or skin temperature over the chambers. The use of this type of tissue chamber is wellsuited for studying the pathophysiology of a self-contained, non-immune inflammatory process. The model described in this paper could prove to be very useful in studies of the distribution of anti-inflammatory drugs and the effects of such drugs on various aspects of the inflammatory process.     

Conjunctival mucinous adenocarcinoma in an ostrich (Struthio camelus)

A 2‐year‐old male ostrich (Struthio camelus) presented with a rapidly growing soft tissue mass protruding from the ventromedial aspect of the right eye (OD). The initial physical examination revealed a soft tissue mass attached to the medial inferior conjunctiva. The mass was excised with cryosurgery, and the conjunctival tissue margins were treated with cryoablation. Histopathological examination diagnosed granulomatous inflammation associated with scattered acid‐fast bacteria. The ostrich recovered uneventfully and appeared healthy until recurrence of a grossly similar mass 2 months later. Gross examination revealed a botryoid mass attached to the inferior palpebral conjunctiva and extending onto the palpebral aspect of the nictitating membrane. Euthanasia was selected, and the histological diagnosis of the second mass was a mixed mucinous adenocarcinoma; however, no acid‐fast bacteria were seen. Granulomatous conjunctival lesions have been previously described in the ostrich, while, to the authors' knowledge, neoplastic conjunctival lesions have not. Neoplasia should be considered as a differential diagnosis for a rapidly recurring, granulomatous conjunctival mass in this species.     

Myocardial sarcocystosis in a grand eclectus parrot (Eclectus roratus) and a Moluccan cockatoo (Cacatua moluccensis)

Cardiac sarcocystosis is described in a grand eclectus parrot and a Moluccan cockatoo. Many cysts containing metrocytes were observed within cardiac muscle fibers on tissue sections stained with hematoxylin and eosin. Characteristic ultrastructural features of the cyst walls included the presence of villous projections containing microtubules. Compartmentalization of the cysts resulted from inward extensions of the cyst wall. The differential diagnosis of sarcocystosis, the life cycle of the parasite, and control measures are discussed.     

Canine mesenchymal hamartoma of the eyelid

Objective Characterization of a benign disease syndrome involving the eyelids of dogs, describing the signalment, clinical appearance, anatomic location, and pathologic features. Animal studied The records and submitted tissue of 10 dogs with mesenchymal hamartomatous lesions of the periocular connective tissues were retrieved from the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) database. Procedure The submitted tissue in each case was stained with hematoxilyn & eosin and Masson’s Trichrome stain and examined histopathologically. Clinical information was collected from the submission requests. The clinical history, treatment, and follow‐up are described in more detail for one of the 10 dogs. Results Seven different breeds, including four Golden Retrievers, were represented. The ages of affected dogs ranged from 6 to 11 years. Eight of 10 lesions were located at the temporal canthus, ranging in diameter from 0.6 to 3 cm. Clinically, the masses were subcutaneous, firm, lobular soft‐tissue growths, which were in some cases adherent to the underlying orbital rim, and in others, freely palpable between the skin and conjunctiva of the eyelid. Histologically, all had distinct margins but were not encapsulated and contained normal appearing collagen‐rich connective tissue with some adipose tissue. Five also contained fully differentiated skeletal muscle tissue arranged in poorly formed aggregates or as individual muscle fibers. Conclusion Mesenchymal hamartoma of the eyelid has not been previously described. The mass has a predisposition to occur at the temporal canthus and should be included in the list of differential diagnoses of benign eyelid masses in dogs.     

Congenital lipoblastoma in a neonate calf: first report in veterinary literature

Lipoblastoma is a rare benign tumour of adipose tissue that usually occurs in young children. Although around 100 cases of lipoblastoma have been reported in humans, no report has been previously described in animals. This case report describes the clinical and histopathological findings of a congenital lipoblastoma located at the tail base of a 2-day-old male calf. Grossly, the mass was pink with a partly ulcerated and haemorrhagic surface. The calf showed no neurological deficits. Radiographs of the vertebral column revealed no abnormalities, and surgical excision was performed. Histopathology of the mass was consistent with lipoblastoma. The calf was followed up for 13 months and found to be healthy with no signs of recurrence. To the best of the authors' knowledge, this is the first case of lipoblastoma in the veterinary literature. Lipoblastoma should thus be considered in the differential diagnosis list for congenital adipose tissue tumours in animals.