Effects of Carbenoxolone on the Canine Pituitary-Adrenal Axis

Cushing’s disease caused by pituitary corticotroph adenoma is a common endocrine disease in dogs. A characteristic biochemical feature of corticotroph adenomas is their relative resistance to suppressive negative feedback by glucocorticoids. The abnormal expression of 11beta-hydroxysteroid dehydrogenase (11HSD), which is a cortisol metabolic enzyme, is found in human and murine corticotroph adenomas. Our recent studies demonstrated that canine corticotroph adenomas also have abnormal expression of 11HSD. 11HSD has two isoforms in dogs, 11HSD type1 (HSD11B1), which converts cortisone into active cortisol, and 11HSD type2 (HSD11B2), which converts cortisol into inactive cortisone. It has been suggested that glucocorticoid resistance in corticotroph tumors is related to the overexpression of HSD11B2. Therefore it was our aim to investigate the effects of carbenoxolone (CBX), an 11HSD inhibitor, on the healthy dog’s pituitary-adrenal axis. Dogs were administered 50 mg/kg of CBX twice each day for 15 days. During CBX administration, no adverse effects were observed in any dogs. The plasma adrenocorticotropic hormone (ACTH), and serum cortisol and cortisone concentrations were significantly lower at day 7 and 15 following corticotropin releasing hormone stimulation. After completion of CBX administration, the HSD11B1 mRNA expression was higher, and HSD11B2 mRNA expression was significantly lower in the pituitaries. Moreover, proopiomelanocortin mRNA expression was lower, and the ratio of ACTH-positive cells in the anterior pituitary was also significantly lower after CBX treatment. In adrenal glands treated with CBX, HSD11B1 and HSD11B2 mRNA expression were both lower compared to normal canine adrenal glands. The results of this study suggested that CBX inhibits ACTH secretion from pituitary due to altered 11HSD expressions, and is potentially useful for the treatment of canine Cushing’s disease.     

Treatment of Chronic Gastric Ulcer with Carbenoxolone and Gefarnate: A Comparative Trial

In 68 patients with chronic gastric ulcer treated in an outpatient clinical trial with either carbenoxolone or gefarnate ulcer healing was consistently greater during carbenoxolone treatment, even though the dose of gefarnate was ultimately increased to four times that recommended. One-third of the patients receiving carbenoxolone gained weight rapidly and unexpectedly, and were given diuretic treatment, compared with two of the 35 patients receiving gefarnate, neither of whom developed clinical oedema.     

Pectin-Based Bioadhesive Delivery of Carbenoxolone Sodium for Aphthous Ulcers in Oral Cavity

The objective of this study was to prepare and evaluate the pectin-based dosage form for buccal adhesion. Carbenoxolone sodium, which is used for the treatment of aphthous ulcers in oral cavity, was used as a model drug. The pectin buccal discs were prepared by direct compression. The water uptake and erosion of pectin disc increased progressively with the swelling time. The bioadhesion of dried pectin discs decreased when either the discs were hydrated or the buccal tissue was wet with a small volume of medium. The influencing factors such as pectin type, pectin to lactose ratio, and sweetener type on the formulations were investigated. The results demonstrated that buccal discs prepared from pectin with a high degree of esterification (DE) showed a weaker and more friable characteristic than that with low DE. Decreasing pectin to lactose ratio resulted in the high dissolution rate with low bioadhesive properties. Addition of sweetener in the formulations also affected the hardness, friability, and bioadhesive properties of the discs. The pectin discs containing sweetening agent showed a higher drug release than those without sweetener. The results suggested that pectin-based bioadhesive discs could be used to deliver carbenoxolone sodium in oral cavity.     

Comparison of Remote Versus In-Person Behavioral Consultation for Treatment of Canine Separation Anxiety

To investigate the validity of remote consultation for treatment of canine separation anxiety, this study compared the efficacy of 2 types of behavioral services offered by Tufts Cummings School of Veterinary Medicine (TCSVM): (a) “PetFax,” a remote consultation service in which dog caregivers (owners) and a certified applied animal behaviorist correspond via fax or email and (b) in-person clinic consultation, which requires that owners bring their dogs to the Animal Behavior Clinic at TCSVM to consult with a board-certified veterinary behaviorist, a veterinary behavior resident, or a certified applied animal behaviorist. The study tested 4 variables for significant differences between PetFax users and clinic visitors: (a) pre- and posttreatment anxiety scores; (b) owner-reported improvement; (c) percentage of rehomed dogs, dogs relinquished or euthanized because of separation anxiety; and (d) clarity of communication with owners. The study found no significant differences between the groups. Difference scores and owner reports demonstrated substantial reduction in separation anxiety in both groups. Results indicate remote consultation is a valid way for behavioral professionals to share behavior modification advice with owners regarding canine separation anxiety.     

Long-term Study of Disodium Cromoglycate in Treatment of Severe Extrinsic or Intrinsic Bronchial Asthma in Adults

The results are reported here of a long-term double-blind controlled clinical trial of disodium cromoglycate (D.S.C.G.) and isoprenaline, D.S.C.G. alone, isoprenaline alone, and a placebo given as a powder for inhalation in the treatment of severe bronchial asthma.At the end of one year 16 out of 20 patients on D.S.C.G.-isoprenaline remained on the allocated capsules, compared with 10 out of 15 on D.S.C.G., 5 out of 20 on isoprenaline, and 3 out of 19 taking the placebo. The differences between each of the D.S.C.G.-isoprenaline and D.S.C.G. regimens compared with the isoprenaline and placebo regimens were statistically significant. After eight weeks on four capsules a day the patients in each group were allocated at random so that half continued on full dosage and half on a reducing regimen. At the end of the year there was no significant difference in the failure rate between patients allocated the full dosage and the patients on the reducing dosage. The capsules were well tolerated and toxicity to D.S.C.G. was not observed.     

Successful Treatment of Canine Sporotrichosis with Terbinafine: Case Reports and Literature Review

Sporotrichosis occurs worldwide, and the metropolitan region of Rio de Janeiro, Brazil, is a main endemic area, with a large number of human and animal cases in the last 19 years. This mycosis is more frequently described in cats rather than in dogs. There are a limited number of oral antifungal agents for the treatment of sporotrichosis in animals. In this context, the effectiveness of terbinafine in the treatment of sporotrichosis in humans, as well as the promising results of in vitro susceptibility tests, inspired us to use this drug in the therapy of this mycosis in dogs. We reported for the first time the use of terbinafine in the treatment of two dogs with sporotrichosis caused by Sporothrix brasiliensis. Moreover, we provided an overview of therapeutic features of canine sporotrichosis cases reported since the 1960s. One of the dogs presented the fixed cutaneous form of the disease, while the other patient presented hyperemia of the nasal mucosa and respiratory signs only. Terbinafine showed high antifungal activity in vitro against the canine Sporothrix isolates. The dogs were successfully treated with terbinafine, with remission of all clinical signs initially presented. The current reports indicate that this drug can emerge as a therapeutic option for canine sporotrichosis.     

建立犬肺渐次萎陷动物模型的实验研究

目的:术中定位是微小肺癌手术面临的主要难题,而原因则是肺在术中萎陷造成的巨大形变。我们从研究肺的术中萎陷着手,建立肺渐次萎陷动物模型,模拟肺在术中发生的萎陷,用以研究肺萎陷的过程、规律及影响因素,为微小肺癌的术中定位提供理论基础。本文用渐进的人工气胸模拟肺在术中的渐次萎陷过程,探讨简便、有效的肺渐次萎陷动物模型的制作方法。方法:健康成年犬12只机等分入左、右侧手术组麻醉后移至CT扫描床采用切小口置管和胸腔穿刺两种方式制作人工气胸。向胸膜腔内分次、定量地注射气体,使肺逐渐萎陷直至完全萎陷。通过夹闭气管插管协助稳定肺的萎陷状态。将各萎陷状态分别进行CT扫描。结果:所有实验犬均顺利完成实验麻醉良好,无意外情况发生。9只犬给予气管插管,3只未给予气管插管;4只犬采用切小口置管方式制作气胸,8只采用胸腔穿刺方式。气管插管增加了模型制作难度,但有利于稳定肺的萎陷状态;胸腔穿刺方式相对操作更为简便。随着向胸膜腔内注射气体,肺缓慢而均匀地向肺门方向集中,萎陷进程满意。CT扫描记录了肺从膨胀到萎陷的各阶段,经过后期重建再现了肺的萎陷过程。5只犬出现并发症,均通过改变操作得以纠正,未影响实验进程。结论:本研究建立的肺渐次萎陷动物模型,能够很好地模拟肺在术中的萎陷过程,是研究术中肺萎陷的理想动物模型。     

Canine CNGA3 Gene Mutations Provide Novel Insights into Human Achromatopsia-Associated Channelopathies and Treatment

Cyclic nucleotide-gated (CNG) ion channels are key mediators underlying signal transduction in retinal and olfactory receptors. Genetic defects in CNGA3 and CNGB3, encoding two structurally related subunits of cone CNG channels, lead to achromatopsia (ACHM). ACHM is a congenital, autosomal recessive retinal disorder that manifests by cone photoreceptor dysfunction, severely reduced visual acuity, impaired or complete color blindness and photophobia. Here, we report the first canine models for CNGA3-associated channelopathy caused by R424W or V644del mutations in the canine CNGA3 ortholog that accurately mimic the clinical and molecular features of human CNGA3-associated ACHM. These two spontaneous mutations exposed CNGA3 residues essential for the preservation of channel function and biogenesis. The CNGA3-R424W results in complete loss of cone function in vivo and channel activity confirmed by in vitro electrophysiology. Structural modeling and molecular dynamics (MD) simulations revealed R424-E306 salt bridge formation and its disruption with the R424W mutant. Reversal of charges in a CNGA3-R424E-E306R double mutant channel rescued cGMP-activated currents uncovering new insights into channel gating. The CNGA3-V644del affects the C-terminal leucine zipper (CLZ) domain destabilizing intersubunit interactions of the coiled-coil complex in the MD simulations; the in vitro experiments showed incompetent trimeric CNGA3 subunit assembly consistent with abnormal biogenesis of in vivo channels. These newly characterized large animal models not only provide a valuable system for studying cone-specific CNG channel function in health and disease, but also represent prime candidates for proof-of-concept studies of CNGA3 gene replacement therapy for ACHM patients.     

Canine Gastrointestinal Pythiosis Treatment by Combined Antifungal and Immunotherapy and Review of Published Studies

Pythium insidiosum is an oomycete, a fungal like microorganism, which infects mammals, causing pythiosis in animals and humans, especially in tropical and subtropical regions around the world. The treatment for this infection is very difficult, and therapeutic options commonly comprise surgery, immunotherapy and antimicrobial drugs. The present report describes the clinical healing of a dog with gastrointestinal pythiosis by treatment with a combination of antifungals and immunotherapy, as well as reviews the cases reported in the literature that used some type of therapy for canine pythiosis. A 2.5-year-old male beagle initially showed sporadic vomiting episodes, and this symptom became more frequent 5 months after the onset of clinical signs. Celiotomy procedure found thickness of the stomach wall extending to the pylorus and duodenum. A biopsy was performed, and the diagnosis of pythiosis was made by mycological, histopathological analyses and molecular identification. Therapy was based on an association of terbinafine plus itraconazole during 12 months and immunotherapy for 2.5 months. The healing of the dog reported here allows us to propose the use of immunotherapy associated with antifungal therapy to treat canine gastrointestinal pythiosis. However, additional studies should be performed on a larger number of patients to establish a standard treatment protocol for canine pythiosis.     

犬用钩端螺旋体抗体ELISA检测实验研究

通过对犬用钩端螺旋体病(钩体)ELISA检测方法的研究,建立了犬用ELISA钩体抗体检测方法。实验的最佳方案:包被抗原蛋白质含量为20μg/mL,酶结合物稀释度为1∶10 000,检测血清稀释度为1∶160。经10份犬免疫血清验证,均为阳性。此研究为犬用钩体抗体检测提供了一种简便快速的方法,具有重要的实用价值。     

正畸治疗上颌尖牙埋伏阻生38例的临床分析

目的:探讨正畸导萌治疗上颌尖牙埋伏阻生的临床效果。方法:对38例上颌尖牙埋伏阻生患者的临床资料进行回顾性分析,总结正畸导萌治疗上颌尖牙埋伏阻生的临床效果。结果:经过17-25个月(平均20个月)的正畸治疗,38例上颌埋伏阻生尖牙均完全萌出纳入到正常牙列中,牙齿及牙周组织未见异常,牙齿排列整齐且咬合关系良好,临床效果令人满意。结论:正畸配合外科手术导萌可有效避免上颌尖牙因埋伏阻生而拔除给患者带来的美观和功能上的缺憾,是一种有效治疗上颌尖牙埋伏阻生的方法。     

Identification of Quantitative Trait Loci (QTL) for Canine Hip Dysplasia and Canine Elbow Dysplasia in Bernese Mountain Dogs

A genome-wide association study for canine hip dysplasia (CHD) and canine elbow dysplasia (CED) using the Illumina canine high density bead chip had been performed for 174 Bernese mountain dogs. General and mixed linear model analysis identified two different regions with single nucleotide polymorphisms (SNPs) on dog chromosome (CFA) 14 significantly associated with CHD and a further significantly CHD-associated region on CFA37. For CED, four SNPs on CFA11 and 27 were significantly associated. The identified SNPs of four associated regions included nearby candidate genes. These possible positional candidates were the genes PON2 on CFA14 and FN1 on CFA37 for CHD and the genes LMNB1 on CFA11 and WNT10B on CFA27 for CED.     

Canine parvovirus-like particles, a novel nanomaterial for tumor targeting

Specific targeting of tumor cells is an important goal for the design of nanotherapeutics for the treatment of cancer. Recently, viruses have been explored as nano-containers for specific targeting applications, however these systems typically require modification of the virus surface using chemical or genetic means to achieve tumor-specific delivery. Interestingly, there exists a subset of viruses with natural affinity for receptors on tumor cells that could be exploited for nanotechnology applications. For example, the canine parvovirus (CPV) utilizes transferrin receptors (TfRs) for binding and cell entry into canine as well as human cells. TfRs are over-expressed by a variety of tumor cells and are widely being investigated for tumor-targeted drug delivery. We explored whether the natural tropism of CPV to TfRs could be harnessed for targeting tumor cells. Towards this goal, CPV virus-like particles (VLPs) produced by expression of the CPV-VP2 capsid protein in a baculovirus expression system were examined for attachment of small molecules and delivery to tumor cells. Structural modeling suggested that six lysines per VP2 subunit are presumably addressable for bioconjugation on the CPV capsid exterior. Between 45 and 100 of the possible 360 lysines/particle could be routinely derivatized with dye molecules depending on the conjugation conditions. Dye conjugation also demonstrated that the CPV-VLPs could withstand conditions for chemical modification on lysines. Attachment of fluorescent dyes neither impaired binding to the TfRs nor affected internalization of the 26 nm-sized VLPs into several human tumor cell lines. CPV-VLPs therefore exhibit highly favorable characteristics for development as a novel nanomaterial for tumor targeting.     

Canine models of copper toxicosis for understanding mammalian copper metabolism

Hereditary forms of copper toxicosis exist in man and dogs. In man, Wilson's disease is the best studied disorder of copper overload, resulting from mutations in the gene coding for the copper transporter ATP7B. Forms of copper toxicosis for which no causal gene is known yet are recognized as well, often in young children. Although advances have been made in unraveling the genetic background of disorders of copper metabolism in man, many questions regarding disease mechanisms and copper homeostasis remain unanswered. Genetic studies in the Bedlington terrier, a dog breed affected with copper toxicosis, identified COMMD1, a gene that was previously unknown to be involved in copper metabolism. Besides the Bedlington terrier, a number of other dog breeds suffer from hereditary copper toxicosis and show similar phenotypes to humans with copper storage disorders. Unlike the heterogeneity of most human populations, the genetic structure within a purebred dog population is homogeneous, which is advantageous for unraveling the molecular genetics of complex diseases. This article reviews the work that has been done on the Bedlington terrier, summarizes what was learned from studies into COMMD1 function, describes hereditary copper toxicosis phenotypes in other dog breeds, and discusses the opportunities for genome-wide association studies on copper toxicosis in the dog to contribute to the understanding of mammalian copper metabolism and copper metabolism disorders in man.