Inherited hyperchylomicronaemia in the cat

Cats with inherited hyperchylomicronaemia show fasting hyperlipidaemia, lipaemia retinalis, xanthomata in a variety of tissues (skin, liver, kidney, etc), peripheral neuropathies and, in some kittens, anaemia. The peripheral nerve lesions result from compression by xanthomata. The fasting hyperlipidaemia is characterised by hypertriglyceridaemia with elevation of chylomicrons and often mild very low density lipoprotein elevation. Lipoprotein lipase (LPL) activity measured after heparin injection, is absent or reduced. In one family, a high concentration of enzyme mass is present and the cats produce an abnormal LPL enzyme protein which fails to bind to the vascular endothelium. The defect is inherited as an autosomal recessive trait. Molecular analyses have not identified any major structural rearrangement in the LPL gene, but it has been suggested that a point mutation is present in the heparin binding domain of the protein (of one affected family).     

Inherited eye disease in the dog and cat

This paper describes the more common inherited eye conditions in the dog and cat, paying particular attention to the newer conditions, not all of which have previously been reported in the literature. These newer conditions include entropion in the shar pei, microphthalmos in the dobermann and miniature schnauzer, cataract in the German shepherd dog and Norwegian buhund, progressive retinal atrophy in the Tibetan terrier, Tibetan spaniel, miniature longhaired dachshund and two forms in the Abyssinian cat, multifocal retinal dysplasia in the English springer spaniel and other breeds, persistent hyperplastic primary vitreous in the Staffordshire bull terrier and dobermann and optic nerve hypoplasia in the toy poodle. Anatomical classification presents a convenient means of describing these conditions which may affect the whole globe, the eyelids, the nictitating membrane, the nasolacrimal duct system, the conjunctiva, the cornea, the aqueous, the iris, the lens and zonule, the vitreous, the retina, the choroid and sclera and the optic nerve.     

Lipoprotein metabolism and hyperlipidaemia in the clog and cat: A review

The term hyperlipidaemia is used to describe raised plasma concentrations of cholesterol and, or, triglycerides. These aqueous insoluble lipids are transported through plasma in special particles called lipoproteins of which there are four main types; chylomicrons, very low density lipoproteins (VLDL), low density lipoproteins (LDL) and high density lipoproteins (HDL). A transient rise in plasma triglycerides occurs following a meal as dietary fat is carried from the small intestine into the circulation by chylomicrons; this is called post prandial hyperlipidaemia. In addition, hyperlipidaemia is caused by defects in the metabolism of one or more of the lipoprotein classes which may be either genetic in origin or, more commonly in the dog and the cat, secondary to diabetes mellitus, hypothyroidism, hyperadrenocorticism, and renal and hepatic disease. Hypertriglyceridaemia is caused by reduced clearance of chylomicrons and VLDL, sometimes with overproduction of VLDL, whereas hypercholesterolaemia results from altered metabolism of LDL and HDL. Raised plasma triglycerides interfere with a number of clinical chemistry tests and may be associated with cutaneous xanthomata, vomiting and diarrhoea, peripheral nerve paralyses, seizures, pancreatitis, hepatosplenomegaly and lipaemia retinalis. The clinical manifestations of hypercholesterolaemia in the dog are few and largely confined to the eye. Diagnostic efforts should concentrate on determining whether the hyperlipidaemia is either genetic in origin or secondary to endocrine and systemic diseases. Plasma lipid concentrations usually return to normal with effective therapy of any underlying disease. Where no such disease can be identified, the hyperlipidaemia should be considered idiopathic in origin and the patient placed on a low fat diet.     

绵羊MSTN基因结构和功能的生物信息学分析

为了研究绵羊肌肉生长抑制素(MSTN)基因结构和功能,试验采用生物信息学方法对其编码蛋白的结构、理化性质、信号肽、跨膜结构、亚细胞定位、功能分类、二级结构、高级结构和功能结构域进行生物信息学分析并推测与其他物种的生物进化关系。结果表明:绵羊MSTN蛋白是一个疏水性不稳定蛋白,作为信号肽的可能性很大;含有9个α-螺旋、11个β-折叠、25个β-转角、1个跨膜结构区域,其功能域可能位于278～375位氨基酸处;绵羊MSTN基因在人、牛、黑猩猩、大鼠、狗、鸡等物种中与牛的亲缘关系最近。     

肌抑素基因的结构、功能及应用

肌抑素(myostatin)属于TGF-β超家族成员,是动物骨骼肌生长的主要负调控因子。对肌抑素基因及其功能的研究,有助于提高畜禽的产肉性能和肉品质,也有利于治疗人类肌萎缩症等肌肉疾病。另外,肌抑素还具有降低脂肪含量,修复骨组织等功能。本文对肌抑素基因的结构、功能及应用进行了简要概述。     

Inherited disorders: the comparative picture

When confronted with a novel familial disorder, veterinarians should consult McKusick's catalogue of inherited disorders in humans, called Mendelian Inheritance in Man (MIM), or its online version (OMIM), to see whether a similar disorder has been reported in humans. They should also consult the other readily available sources of comparative information on mice and domesticated species. Increasingly, such consultations can be conducted on the Internet via the World Wide Web. If it is thought that an animal disorder is homologous with a human disorder, publications describing the animal disorder should include the MIM number(s) for that disorder. Future research can then test the hypothesis of homology, until a consensus is reached.     

Thyroid function in the cat: assessment by the TRH response test and the thyrotrophin stimulation test

Changes in total thyroxine (T4), free T4 and total tri-iodothyronine (T3) were measured in 13 cats after the intravenous injection of varying doses of thyrotrophin stimulating hormone (TSH) (0–5 U/cat n = 6; 1 U/cat n = 8; 1 U/kg bodyweight, n = 7) or thyrotrophin releasing hormone (TRH) (100 ug/cat, n = 10). All three doses of TSH resulted in a significant (P < 0–05) rise in T4, free T4 and T3 levels, with the mean peak in hormone concentrations occurring six to eight hours after injection. The three doses of TSH all appeared to produce maximal stimulation of thyroid hormone secretion. The mean percentage increase in hormone concentrations at seven hours following the three doses of TSH ranged from 167 to 198 per cent for T4, 240 to 365 per cent for free T4, and 73 to 116 per cent for T3. Following administration of TRH there was also a significant (P < 0–05) rise in T4, and free T4. The mean peak in T4 and free T4 levels occurred at four hours, and mean increases in hormone levels at this time were 92 per cent for T4, and 198 per cent for free T4. The administration of TRH produced little change in T3 levels. TSH administration resulted in a significantly higher (P < 0–05) percentage peak increase in T4, free T4 and T3 levels at all three dosages than did TRH.     

Presence and diversity of the beta-lactamase gene in cat and dog staphylococci

Staphylococci are part of the normal microflora of humans and animals and some are potential pathogens that have become resistant to almost all known antibiotics. Despite the widespread reports of penicillin resistance in cat and dog staphylococci, the mechanism underlying penicillin resistance has not been examined. This study was aimed at investigating the molecular basis of resistance to penicillin in cat and dog staphylococcal isolates that showed phenotypic resistance to beta-lactam antibiotics. An 861 bp fragment of the structural blaZ gene which codes for beta-lactamase production in staphylococci was amplified by polymerase chain reaction (PCR) and the products were sequenced. Sequenced fragments were analysed by protein signature typing and sequences were compared to published blaZ sequences of human and bovine staphylococcal strains held in a public database. Four known protein signature types (1, 3, 5 and 6) and one new type (12) were identified in this study. When sequences were compared with published blaZ sequences, gene phylogenetic analysis revealed three major groups. The four variants of beta-lactamases types (A, B, C and D) belonged to each major group except for types A and D which were both in group II. These findings confirm that the blaZ gene is responsible for beta-lactamase production leading to subsequent resistance to beta-lactam antibiotics in feline and canine staphylococci and that the gene shows similar diversity and relatedness as found with blaZ sequences obtained from human and bovine staphylococci.     

Effect of nonadrenal illness on adrenal function in the cat

Adrenal function was assessed by a combined dexamethasone suppression-ACTH stimulation test in 18 healthy cats, 17 diabetic cats, and 19 sick nondiabetic cats. In all groups, plasma cortisol concentrations decreased after dexamethasone was administered and increased after ACTH was administered. There were no significant (P greater than 0.05) differences among groups in time trend changes in cortisol concentration. There was considerable variation in adrenal response between cats in each group. Diabetic cats had more variation in base-line and postdexamethasone plasma cortisol concentrations (P less than 0.05) than did other groups. In sick, nondiabetic cats, cortisol concentrations tended to be higher in cats with hyperthyroidism (P = 0.06) than in cats with other diseases.     

Adrenocortical function in the domestic cat during treatment with levonorgestrel

Levonorgestrel was administered via a subcutaneous, slow-release silastic implant to 10 queens. Five other queens served as controls. Their adrenocortical function was assessed by the adrenocorticotrophic hormone (ACTH) stimulation test before and after one, two, six and 12 months of treatment. In addition, the gross anatomy and histology of the adrenal gland were examined post mortem in six of the treated cats. In both the control and treated queens the plasma cortisol concentrations (pre and post ACTH) were significantly different (P<0·05) at different times. However, there were no significant differences between the plasma cortisol concentrations (pre and post ACTH) of the treated and control queens. No gross or microscopical abnormalities were visible in the adrenal glands of the treated queens.     

Adrenal function testing in the cat: the effect of low dose intravenous dexamethasone administration

The plasma cortisol responses of 11 normal cats to intravenous dexamethasone at a dose rate of 0.01 mg kg-1 whole bodyweight, were evaluated. Mean plasma cortisol concentrations decreased significantly (P less than 0.01) at three hours and eight hours following dexamethasone administration. Results of this study indicate that plasma cortisol levels are significantly decreased for at least eight hours following low dose intravenous dexamethasone administration in normal cats.     

Properties of the tumor suppressor gene brca2 in the cat

Mammary tumors are common in cats. As mutations in human Brca2 confer an increased risk of breast cancer, the full-length cDNA of the feline homologue of Brca2 was sequenced to obtain a basis for studying the relationship between its function and susceptibility to mammary tumors. The feline Brca2 cDNA is 10 kb long, and encodes 3,371 amino acids. The amino acid sequence of feline Brca2 shares low homology with the Brca2 of other mammals, e.g., 53% homology with the murine protein. Analysis of the expression pattern of the feline Brca2 gene revealed that, as previously reported for other mammals, it is transcribed in various tissues, including the mammary gland.     

抗菌肽的构效关系及其基因表达调控的研究进展

论述了抗菌肽分子结构与功能之间的关系,抗菌肽的抗菌机制及其基因的表达调控途径,阐明了不同来源的抗菌肽均有相似的抗病机理,但来源不同的抗菌肽有其独特的表达方式及调控途径。认为研究抗菌肽的调控机制,对深入认识机体抵抗病原体的侵袭方式及机理,进而人为调控抗菌肽的表达具有重要意义。     

猪CD8β基因的克隆、表达及其结构与功能分析

本研究应用RT-PCR技术,从猪胸腺细胞总RNA中扩增、克隆了猪CD8β基因,序列分析表明CD8β含621 bp的开放阅读框,编码207个氨基酸,与NCBI/GeneBank已发表的参考基因的核苷酸及推导氨基酸序列的同源性分别为97.8%和96.8%,与人、小鼠和鸡CD8B蛋白的氨基酸同源性分别为75.7%、67.9%和33.3%.根据大肠杆菌密码子偏嗜性改造目的基因,构建了pET28a/PCD8 β原核表达系统,并经诱导获得高效表达的分子量为24 ku的重组蛋白(rPCD8 β),表达量占菌体蛋白总量的30%.利用生物信息学和分子生物学软件对猪CD8 β基因编码的蛋白进行结构预测,表明猪CD8 β成熟蛋白为跨膜蛋白,其中172aa在胞外区,22aa在跨膜区,10aa在胞内区;蛋白骨架内含有较多的柔性区域,而且分布不均匀.能形成结构松散的球状蛋白;猪CD8 β分子V区三维结构与鼠的具有非常相似的空间结构,与人的差别较大,这为猪CD8B蛋白结构与功能的进一步研究奠定了基础.     

Investigation of the effects of hyperthyroidism on renal function in the cat.

This study evaluated the effects of thyroxine on renal function in the cat. Baseline serum thyroxine (T4) concentrations, clinicopathologic data (complete blood count [CBC], serum chemistry panel, urinalysis), and nuclear medicine determinations of glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and effective renal blood flow (ERBF) were measured in 10 normal adult cats. Cats were then injected with thyroxine (T4) (50 micrograms/kg SQ) daily for 30 d to induce hyperthyroidism. Clinicopathologic and nuclear medicine studies were repeated at 30 d. Cats injected with thyroxine had significant increases in T4, GFR, and ERBF and significant declines in serum creatinine and blood urea nitrogen (BUN) values. Administration of high doses of exogenous thyroxine to cats results in significant stimulation of renal function.     

Partial characterization of structure and function of a xylanase gene from the rumen hemicellulolytic bacterium Eubacterium ruminantium

A gene encoding for xylanase activity in the rumen hemicellulolytic bacterium Eubacterium ruminantium was cloned into pBR322 in Escherichia coli (E. coli ). The primary clone had a 5.7 kb insert produced by Eco RI partial digestion. Subcloning followed by sequencing allowed for the discovery that this enzyme has a glycosyl‐hydrolase family 10 catalytic domain with a family 9 carbohydrate binding module at C‐terminus and a region partially homologous to a family 22 carbohydrate binding module at N‐terminus. Cloned xylanase is specifically active against xylan and oligoxyloside to produce xylobiose and xylotriose, showing optimal pH and temperature at 7.0 and 50°C, respectively. Molecular size of the xylanase (91 kDa) was confirmed by zymogram analysis of the E. coli clone, which agreed with the predicted size from the DNA sequence. Functions of the two modules at C‐ and N‐termini were evaluated by using xylanase variants with and without the respective module and the C‐terminal module was found to be functional in binding to acid‐swollen cellulose and insoluble oat‐spelt xylan, whereas the N‐terminal module was inactive for binding them.     

鸭源鸡杆菌外膜蛋白W基因克隆及结构与功能分析

参考GenBank中鸭源鸡杆菌(Gallibacterium anatis,G.anatis)UMN179的外膜蛋白W(outer membrane protein W,OmpW)基因序列设计1对引物,对鸭源鸡杆菌PDS-RZ-1-SLG株的OmpW基因进行克隆、测序,并通过生物信息学软件对该蛋白结构与功能进行分析及预测。结果显示:OmpW基因大小为705bp,编码234个氨基酸;与鸭源鸡杆菌UMN179株、F149株及12656/12株的OmpW氨基酸同源性分别为88.9%、78.7%和79.6%;OmpW相对分子质量为25 300,等电点为7.88,是能够稳定存在的蛋白,N端有1个疏水性的α螺旋信号肽,C端有1个疏水性的β折叠区域,并且在外膜表面存在1个保守性的B细胞线性表位。本试验成功克隆了鸭源鸡杆菌PDS-RZ-1-SLG株的OmpW基因,并对其结构与功能进行初步分析和预测,为进一步研究其生物学功能及其应用奠定基础。     

Inherited copper toxicosis in the Bedlington terrier: the prevalence in asymptomatic dogs

Copper toxicosis in the Bedlington terrier is an inherited defect. This paper describes the investigation of 62 Bedlington terriers, none of which had shown any clinical signs of liver disease, in order to assess the prevalence of copper toxicosis in the breed in the United Kingdom. Twenty one (33·9 per cent) of the dogs investigated had abnormally high levels of copper in the liver. No reliable circulating haematological or biochemical parameters were found to identify those dogs with increased hepatic copper levels and the diagnosis could only be established by liver biopsy. Affected dogs had liver copper levels of between 257·5 and 2558·0 μpg per g of wet weight (1163·8 ± 164 μg/g, mean ± SEM) compared with normal dogs which had between 9·9 and 118·6 μg/g of wet weight (49·0 & 4·4 μg/g, mean ± SEM). Copper accumulation in the liver of affected dogs could also be detected on histological examination using special stains.