Morphological study of tracheal shape in donkeys with and without tracheal obstruction

Reason for performing study: There is limited information on the gross tracheal morphology of donkeys with or without tracheal abnormalities. Objectives: To: 1) examine the morphology of tracheas of donkeys with and without clinical and/or post mortem evidence of tracheal obstruction; 2) record the cross‐sectional dimensions and shapes of tracheal rings at fixed sites; and 3) document prevalence, sites and characteristics of detected tracheal abnormalities. Methods: The tracheas of 75, predominantly aged (median age 30 years, range 7–48 years) donkeys that died or were subjected to euthanasia on humane grounds were examined. Five had severe dyspnoea due to tracheal obstruction (with intercurrent lung disease in 3), while 7 had post mortem evidence of severe tracheal airway obstruction. Every 5th tracheal ring was dissected free and the inner and outer vertical and transverse dimensions and cross sectional areas were measured. Each dissected ring was photographed and the shape of the trachea was classified as normal or, in one of 6 abnormal grades, according to the type and degree of structural abnormality present. Results: The tracheas had a mean of 43 (range 34–50) tracheal rings that tended to be more oval in shape in the distal cervical region. Only 31.2% of rings examined had a circular to oval shape. Dorso‐ventral flattening was present in 0.9% of tracheal rings, dorsal ligament separation in 24.4%, slight cartilage deformity in 26.0%, moderate cartilage deformity in 10.4%, marked cartilage deformity in 1.9% and miscellaneous other abnormalities in 4.9% of tracheal rings. The 12 donkeys with ante or post mortem evidence of tracheal obstruction had significantly increased tracheal abnormality grade in comparison to the remaining donkeys. Conclusions and potential relevance: Structural tracheal abnormalities are present in most old donkeys, but generally do not cause clinical problems in these sedentary animals unless intercurrent pulmonary disease is present.     

Sustained exercise improves vertebral histomorphometry and modulates hormonal levels in rainbow trout

Abnormal compressions and fusions of vertebral bodies are frequently observed in reared rainbow trout and could result from chronic and unbearable muscle pressures acting on the axial skeleton during intensive growth. Sustained swimming at moderate speeds was shown to induce many positive effects on growth and swimming performances in salmonids, but yet little is known about its effects on vertebral remodeling processes and related hormonal regulation. Rainbow trout were subjected to three different swimming speeds (0, 1.0 and 1.5 body length (BL) s^− 1), starting one month after they were first fed (65 mm) and ending when they reached 260 mm in size (market-size of 275 g). At the end of the experiment, 20 trout were sampled in each lot (N = 60) and blood samples were taken. Vertebrae abnormalities were assessed by radiological examinations. Vertebrae from the middle axial region (V32–38) were selected to evaluate bone mineralization (BM) and total bone area (Tt-B.Ar.) on radiographed transverse sections (125 ± 10 μm). Assays were performed to evaluate mineral homeostasis (calcemia and phosphatemia), bone cell activities (alkaline phosphatase, ALP, and tartrate-resistant acid phosphatase, TRAP) and bone regulating hormones (calcitonin, CT and thyroid hormones, THs). Sustained exercise reduced the appearance of fused vertebrae, enhanced vertebral BM and decreased vertebral Tt-B.Ar., while it increased circulating CT and TH levels. No variations were observed on mineral homeostasis and bone cell activities. Increasing the swimming speed up to 1.5 BL s^− 1 had positive effects on the vertebral skeleton, and therefore, seems to be a suitable approach to prevent aggravation of vertebral abnormalities in juvenile trout. The changes observed in vertebral features are interpreted as a compromise between the necessity to mobilize vertebral mineral ions in response to various physiological demands and to maintain vertebral strength against mechanical constraints.     

Thermal stability of the synthetic peptides with the sequence of fish fast skeletal muscle tropomyosin

Tropomyosins from fish skeletal muscle show high amino acid sequence homology, although their thermal stability is clearly different among species. In order to determine the regions that are responsible for the stability of this protein, five synthetic peptides of 30mer were synthesized by Fmoc method, based on the sequence of walleye pollack Theragra chalcogramma fast skeletal muscle tropomyosin, namely, N terminal Met¹-Lys³⁰, the variable region Asp⁸⁴-Leu¹¹³, the middle region Val¹²⁸-Ala¹⁵⁷, the region containing the conservative Cys (Leu¹⁷⁶-Lys²⁰⁵), and C terminal Asp²⁵⁵-Ile²⁸⁴. The thermal stability of these peptides was measured by circular dichroism and differential scanning calorimetry. The helical contents of these peptides were decreased in a temperature-dependent manner, although they showed no clear melting temperature, suggesting that the enthalpy necessary for the complete denaturation of these peptides was low. Peptides Asp²⁵⁵-Ile²⁸⁴ and Asp⁸⁴-Leu¹¹³ showed the highest and second highest α-helical contents, respectively, and the other peptides gave rise to lower α-helical contents.     

Mucopolysaccharidosis VII in a Cat Caused by 2 Adjacent Missense Mutations in the GUSB Gene

Background

Mucopolysaccharidoses (MPS) are common lysosomal storage disorders causing typically progressive skeletal and ocular abnormalities.

Objectives

To describe the clinic features, metabolic profile and a unique mutation in a domestic shorthair (DSH) kitten with MPS VII.

Animals

Affected kitten and 80 healthy cats.

Methods

Serum lysosomal enzyme activities and urinary glycosaminoglycan (GAG) accumulation were assessed. Exons of the β‐glucuronidase gene (GUSB) were sequenced from genomic DNA and genotyping was conducted.

Results

A 3‐month‐old DSH cat was presented for stunted growth, paresis, facial dysmorphia, multiple skeletal deformities, and corneal opacities. Evaluation of blood smears disclosed metachromatic granules in leukocytes and a urinary mucopolysaccharide spot test was positive. The proband had no GUSB activity but normal or increased activities for other lysosomal enzymes. Sequencing of the GUSB gene from the proband and comparison to the sequence of 2 healthy cats and the published feline genome sequence demonstrated 2 unique single base transitions (c.1421T>G and c.1424C>T) in exon 9, altering 2 adjacent codons (p.Ser475Ala and p.Arg476Trp). These amino acid changes are in a highly conserved domain of the GUSB protein and nontolerable to maintain function. Moreover, the p.Arg476Trp mutation previously has been identified in human patients. None of the other clinically healthy cats had these mutations.

Conclusions and Clinic Importance

The diagnostic approach to MPS disorders is delineated. This is only the second mutation known to cause MPS VII in cats. Similarly, 2 different mutations have been described in MPS VII dogs, thereby showing the molecular heterogeneity of MPS VII in companion animals.     

Retrospective study of outcome following desmotomy of the accessory ligament of the deep digital flexor tendon for type 1 flexural deformity in Thoroughbreds

Objective Determine the long‐term outcome for Thoroughbreds undergoing desmotomy of the accessory ligament of the deep digital flexor tendon (DAL‐DDFT) for type 1 flexural deformity of the distal interphalangeal joint (DIPJ). Design Retrospective matched cohort study Procedure Medical records were retrieved over a 17‐year period for Thoroughbreds that underwent DAL‐DDFT for type 1 flexural deformity. Long‐term outcome was determined by analysis of race records and comparison with maternal siblings. Comparisons between cases and controls included 2‐year‐old, 3‐year‐old and total career performance data. Results There were 46 cases of DAL‐DDFT. The mean age at surgery was 151 days (median 118, range 2–562); 48% of case horses and 77% of 90 controls started in a race. For case horses that did race, the time to first race, total number of starts and prize money per race were not significantly different to maternal siblings. Age at the time of surgery did not alter the likelihood of starting a race. Conclusion Thoroughbreds undergoing DAL‐DDFT for type 1 flexural deformity of the DIPJ are less likely to race when compared with their maternal siblings. For those that do race, the time to first race, total races and earnings per race are not different from controls. There is no evidence to suggest that age at the time of surgery influences the likelihood of racing.     

雄性肉鸡跗关节间外翻—内翻畸形的相关因素剖析

通过对50个家系488只白羽科尼什肉鸡雄性后代1～6周龄生长的观测,跗关节间变形和趾变形均有发生。表现为大跖骨与胫骨之间呈外翻和内翻,趾在自然松弛时扭曲。在6周龄关节变形的鸡中,双腿均外翻占66.2%,右腿、左腿变形分别占16.2%和12.1%,双腿内翻仅占5.5%。4周龄和6周龄关节变形相关系数为0.478(P<0.01)。趾变形与关节变形无相关。2,4,6周龄趾、关节变形鸡平均体重明显高于健康鸡体重。本研究发现,小圈环境、增重速度均影响发病率,家系遗传效应在趾变形中明显,对跗关节间变形的影响亦不能排除,因此建议在肉鸡育种中应加强对骨骼结实性的重视,严格饲养管理程序以减少关节,趾病发生。