Masticatory and skeletal muscle myositis in canine leishmaniasis (Leishmania infantum)

Twenty-four dogs with a parasitologically and serologically established diagnosis of leishmaniasis were studied to investigate the atrophy of the masticatory muscles which commonly occurs in this disease, and to compare the lesions in the masticatory muscles with those in the cranial tibial muscles. The 24 animals were divided into three groups of eight, group A dogs with no muscular atrophy, group B dogs with different degrees of atrophy in the masticatory and skeletal muscles, and group C dogs with similar degrees of atrophy in the masticatory and skeletal muscles. Increased activities of creatine phosphokinase and lactate dehydrogenase were recorded in only some of the dogs in groups B and C, but there were no significant differences between the mean activities in the three groups. Electromyographic changes indicating myopathy and involving both the temporalis and cranial tibial muscles, were observed in two of the dogs in group A, seven of those in group B, and in all the dogs in group C. Muscle histopathology revealed a variable degree of muscle fibre necrosis and atrophy, mononuclear infiltrates and neutrophilic vasculitis in all the dogs except two in group A. Leishmanial amastigotes were found within macrophages and myofibres in 16 of the dogs, some in each group. IgG immune complexes were detected in muscle samples, and circulating antibodies against myofibres were detected in serum samples from all the 24 dogs.     

Computed tomographic appearance of masticatory myositis in dogs: 7 cases (1999-2006)

OBJECTIVE: To document computed tomography (CT) features in dogs with masticatory myositis. DESIGN: Retrospective case series. ANIMALS: 7 dogs with an immunologic diagnosis of masticatory myositis and an absence of clinical abnormalities of any skeletal muscles other than the masticatory muscles. PROCEDURES: History; clinical, hematologic, biochemical, immunologic, cytologic, and histologic findings; and pre- and postcontrast CT imaging features of masticatory muscles and head and neck lymph nodes were extracted from medical records. RESULTS: On CT images, changes in size (atrophy or swelling) were common for all masticatory muscles except the digastricus muscles, which were involved only in 1 dog. Pre-contrast attenuation changes, most often hypoattenuation with varied distribution patterns, were seen in masticatory muscles of 4 dogs. Contrast enhancement with a predominantly inhomogeneous distribution pattern was seen in the temporalis, masseter, and pterygoid muscles of all dogs. Head and neck lymph nodes were enlarged in all but 1 dog and had contrast enhancement with predominantly central or homogeneous distribution patterns. Muscle biopsy was performed in 6 dogs, with biopsy specimens obtained from areas that had the most obvious contrast enhancement on CT images. For all 6 dogs, biopsy specimens had histologic features indicative of masticatory myositis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that CT may be a useful adjunct in the diagnosis of masticatory myositis in dogs, including selection of sites for diagnostic muscle biopsy.     

Myotonic dystrophy-like disease in a dog

A mature female Rhodesian Ridgeback was determined to have a progressive, degenerative myopathy associated with myotonia, dysphagia, and marked muscle wasting. Clinical findings revealed a diffuse muscular disease with percussion dimpling, dysphagia, and creatine kinase elevation. A paroxysmal atrial tachycardia was found. Electromyography revealed a diffuse myopathy with high-frequency bizarre waves, myotonic discharges especially in the masticatory, laryngeal, and pharyngeal muscles. A few positive sharp waves were found in some of the appendicular muscles. Histopathologic and histochemical stains on skeletal muscle biopsy specimens demonstrated moderate fiber-size variation, myofiber architectural changes, muscle-fiber splitting, focal necrosis and phagocytosis, high percentage of internal nuclei, and atrophy of type-2 muscle fibers. A review of myotonic myopathies in the dog is presented. The clinical, electrophysiologic, and histochemical findings are similar to those for myotonic muscular dystrophy in man.     

Congenital myopathy in Japanese Black calves

Two Japanese Black bull calves from a dam showed muscular weakness and became recumbent after birth. At necropsy, skeletal muscles, including face, neck, body and proximal and distal forelimb and hindlimb were extremely pale in color and edematous. Histopathological examination of skeletal muscles revealed degenerative changes as follows: replacement of muscle with fat, variation in muscle fiber diameter, internal nuclei, central core-like structures, and vacuolar and hyaline degeneration of muscle fibers. Ultrastructurally, the lesions were characterized by focal myofibrillar disorganization with streaming or irregularity of Z bands. The present cases seem to be classified as congenital myopathy based on pathological alterations and age of onset.     

维生素E缺乏对鲤骨骼肌损伤的影响

本文旨在探讨VE缺乏对鲤骨骼肌损伤的形态学影响。在半纯合日粮中分别添加0、25、50和100 mg/kg的VE,投喂体重约60 g的鲤鱼20周。结果表明:鲤鱼摄入VE缺乏的饲料后,出现“瘦背症”、脊柱弯曲及以突眼、竖鳞和腹水为特征的渗出性素质样病变。病理剖解见体壁肌肉萎缩,特别是背部两侧肌肉萎缩变薄,其厚度仅为对照组的1/4~1/2,似刀刃状;体侧红肌纤维褪色变白,呈白肌肉外观。组织学变化主要表现为肌营养性不良,骨骼肌变性、坏死,淋巴细胞和单核细胞浸润,大量结缔组织增生,残存的肌纤维萎缩变细。超微结构上表现为骨骼肌细胞核膜间隙增宽,呈锯齿状,并发生局部或广泛性的断裂,核变形,电子密度降低;肌浆内糖原颗粒明显减少,线粒体肿胀,嵴断裂,甚至溶解呈空囊泡状,肌原纤维的横纹模糊不清或完全消失。结论:日粮中0、25和50 mg/kgVE水平会导致鲤出现VE缺乏症,其骨骼肌主要表现为变性、坏死、肌萎缩和炎症细胞浸润的肌营养性不良。     

Histopathological characterization of the skeletal myopathy in rasH2 mice carrying human prototype c-Ha-ras gene

A skeletal myopathy is found in approximately 100% of rasH2 mice. To confirm detailed features of the rasH2 skeletal myopathy, the biceps femoris, diaphragm, triceps brachii, gastrocnemial (types I and II fiber-mixed muscles) and soleus muscle (type I fiber-dominant muscle) obtained from male rasH2 and non-transgenic littermates aged 10-13 and 34 weeks were examined. Variations in the muscle fiber size, early-scattered degeneration/necrosis and regeneration of muscle fibers were detected in 10-13-week-old rasH2 mice. The severity of the above muscular lesions was more prominent in older rasH2 mice. These lesions were noted in the type II myofiber dominant muscles (biceps femoris, triceps brachii and gastrocnemial). NADH-TR stain clearly demonstrated a disorganized intermyofibrillar network and necrotic change in muscle fibers. No specific morphological changes, like rod structure or tubular aggregation seen in some types of myopathy, were noted in Gomori trichrome and NADH-TR stains in the rasH2 mouse like in many types of muscular dystrophy. Electronmicroscopically, occasional muscle fiber degeneration/regeneration, invaded phagocytic cells, indistinct Z-band suggesting excessive contraction and dilatation of the sarcoplasmic reticulum were observed. In summary, the skeletal myopathy occurring in rasH2 mice is consistent with muscular dystrophy characterized morphologically by progressive degeneration and regeneration of myofibers. The myopathy is confined to the type II myofiber predominant muscles and is not associated with any pathognomonic lesions. These characteristics will provide us with a useful model for research in muscular dystrophy of diverse myofibers.     

Anatomy of the orbital fasciae and the third eyelid in dogs

The connective tissue structures commonly referred to as the periorbita, orbital septum, muscular fasciae, and vagina bulbi or collectively, as the orbital fasciae were dissected then illustrated and described. Two sheets (layers) of the periorbita (endorbita) were found in our dogs. The periorbita should be renamed endorbita because of its anatomic relations. The periorbita did not always fuse with the periosteum of frontal and sphenoid bones. Rather, the periorbita and the periosteum were often distinct and separate; only medioventrally did several fibrous bands unite the superficial sheet of the endorbita with the periosteum. Two layers of the endorbita fused with the periosteum of the margin of the bony orbit and with the orbital ligament. The muscular fasciae were divided into 3 layers. The superficial layer extended caudally from the orbital septum, was thick, and was pierced by arteries, veins, and nerves. The middle layer was attached to the sclerocorneal junction and, at the temporal canthus of the eye, was divided into superficial and deep sheets. The deep portion was attached to the lateral angle of the third eyelid, similar to a strong ligament. The deep layer of the muscular fasciae extended caudally from the sclerocorneal junction in intimate contact with recti and oblique muscles of the eyeball. The deep portion of the deep muscular fascia covered the deep surface of all recti muscles and separated them from the retractor bulbi muscle. Intermuscular septa were observed between middle and deep muscular fascia layers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Morphological changes of physeal cartilage and secondary ossification centres in the developing femur of the house mouse (Mus musculus): A micro‐CT based study

In mammals, long bones are formed by ossification of a cartilaginous mould during early stages of development, through the formation of structures called the primary ossification centre, the secondary ossification centres (SOCs) and the physeal cartilages (PCs). The PC is responsible for long bone growth. The morphology of the PC and the SOCs varies during different stages of femoral growth. In this respect, several details involving the process of murine femoral development are lacking. In the present study, a morphological characterization of femur development from the embryonic period to adulthood in mice was studied using micro‐computed tomography (micro‐CT). To achieve this aim, femora were collected at embryonic day (E) 14.5, E16.5 and E18.5 and at postnatal day (P)1, P7, P14, P35, P46 and P52. CT images were obtained using a micro‐CT scanner (X‐SkyScan 1172; Micro Photonics) and analysed using the micro‐CT 3D visualization software Mimics (Materialise NV, Leuven, Belgium) and NRecon (Micro Photonics). The results of the present study revealed that the femur and its PCs and SOCs undergo morphological changes during different stages of development, including changes in their shape as well as position and thickness. These changes may be due to the response of the femur to mechanical loads imposed by muscle surrounding the bone during these stages of development. The result of the present study is important to improve our knowledge related to ossification and growth patterns of mouse femur during development.     

Type,diameter and distribution of fibres in some respiratory and abdominal muscles of the goat

This study was designed to determine the histochemical properties, size and composition of fibres in the diaphragm, intercostal and abdominal muscles of goats to clarify whether reported similarities in respiratory muscle physiology between goats and humans have a structural basis. Serial sections (10 µm) of muscular tissue from adult female goats were stained for myosin adenosine triphosphatase and reduced nicotinamide adenine dinucleotide dehydrogenase-tetrazolium reductase activities; the fibres were classified into types I, IIA and IIB; and their mean diameter and composition were determined. Abdominal and intercostal muscles contained types I, IIA and IIB fibres in the ratio 1:1:1, and the mean diameter of the fibres ranged from 49.2 to 62.2 µm. In contrast, the diaphragm contained 58.9% type I and 41.1% type II fibres, and the latter could not be differentiated into types IIA and IIB. Diaphragmatic fibres were also smaller (36.9 – 40.9 µm). These findings contrast with those in humans, where the diaphragm, intercostal and abdominal muscles contain >50% type I fibres and have fibres of identical diameter. The differences in fibre characteristics between the diaphragm, intercostal and abdominal muscles of goats and the differences between goats and humans need to be taken into consideration in interpreting the results from studies in respiratory muscle physiology.Abbreviations mATPase myosin adenosine triphosphatase - NADH-TR nicotinamide adenine dinucleotide dehydrogenase-tetrazolium reductase     

Long non‐coding RNA analysis of muscular responses to testosterone deficiency in Huainan male pigs

Long non‐coding RNAs (lncRNAs) participated in growth and development of skeletal muscle; however, little is known about their response to testosterone deficiency in porcine skeletal muscle. We compared lean mass related carcass traits and lncRNAs expression files in Longissimus dorsi (LD) muscle between intact and castrated Huainan male pigs. The results showed that castration significantly reduced eye muscle area and lean meat percentage (P < 0.05), but increased the fat mass weight (P < 0.05). Meanwhile, 8946 lncRNAs, including 6743 intergenic lncRNAs (lincRNAs), 498 anti‐sense lncRNAs, and 1705 intronic lncRNAs, were identified in porcine LD, among which, 385 lncRNAs were considered as the differentially expressed candidates between intact groups and castrated groups (q‐value < 0.05). Functional analysis indicated that these differently expressed lncRNAs and their target genes were involved in the estrogen receptor signaling pathway and skeletal and muscular system development and function. We first detect porcine muscular lncRNA response to castration, and the results suggested that lncRNAs and their target genes participated in the regulation of testosterone deficiency‐related skeletal muscle growth.     

Virtopsy in a red kangaroo with oral osteomyelitis

This report describes the use of computed tomography (CT) in a nondomestic species. Postmortem CT was performed on a red kangaroo (Macropus rufus) and a diagnosis of oral osteomyelitis was made. CT examination revealed bony remodeling of the right mandible, an intraosseous lesion of the right temporal bone, muscle necrosis around the right mandible, and the absence of the right, first, upper molar tooth. Cardiac and intrahepatic gas and a distended intestine due to postmortem gas accumulation were also seen. All the lesions identified with CT were also identified by conventional necropsy, except the cardiac and intrahepatic gases. Virtopsy may be a useful procedure for the noninvasive identification of cause of death and as a guide for necropsy in animals.     

TOMY OF THE CANINE BRAIN USING HIGH RESOLUTION OMPUTED TOMOGRAPHY*

High resolution computed tomography (CT) was used to determine the normal appearance of the brain of an adult Beagle dog. Objects as small as 0.6 mm for bony structures (high contrast) and 1.5–2.0 mm for soft tissue structures (low contrast) could be resolved in the CT images. Multiplanar imaging using direct transverse and reformatted dorsal and sagittal images made it possible to obtain a three dimensional presentation of anatomy. Selective viewing, where CT number window and level settings were varied, was used to optimize visualization of specific brain structures. Normal high contrast components, cerebrospinal fluid, and osseous land-marks, were important aids in identification of various intracranial structures. Quantitative densitometry was performed to characterize various regions of the brain in terms of their x-ray attenuation values or CT numbers. This study indicated that high resolution CT provides a qualitative and quantitative appraisal of the canine brain that is unavailable using conventional radiographic technics.     

A scientific background for skeletal muscle conditioning in equine practice

The main goal of any conditioning programme in athletic horses is to improve performance by inducing physiological changes within the animal's body. Equine skeletal muscles have a considerable potential to adapt during training and these adaptations have important physiological implications that influence stamina, strength and speed. Although there is an extensive specialized literature in this regard, scientific based muscle conditioning methods have not been introduced sufficiently in the equine sport practice. After a brief synopsis of both equine muscle exercise physiology and muscular adaptations to training, including their physiological significance, this review focuses on specific training programmes that induce muscular adaptations in athletic horses. The article addresses the following principal question: what kind of stimuli for what kind of muscular adaptations? The experimental data are discussed separately for racehorses (thoroughbreds, trotters and endurance horses) and sport horses (dressage, show jumpers and carriage). Finally, published results about the influence of relevant training parameters (such as intensity, duration and type of exercise) on muscular responses are discussed, as well as those concerning overtraining and detraining. The article closes with some concluding remarks on importance of their application in practice.     

Computed Tomography as a New Tool for Investigating Leg Weakness in Turkeys

Introduction: Leg weakness causes high economic losses in commercial poultry. The unspecific term includes, amongst others, diseases of the skeletal system caused by genetic, nutritional or microbiological factors. The analysis of computed tomography images may be a new tool to discriminate and evaluate skeletal abnormalities in turkeys and can therefore provide valuable hints in the treatment of turkey stocks suffering from leg weakness. Material and Methods: Legs of healthy turkeys and those showing clinical signs of leg weakness were examined using a Tomoscan M/EG/Compact (Philips Medical Systems) CT system. The slice thickness and distance were set to 2 mm. In addition to the evaluation of the obtained images, the software system 3D‐Doctor was used to create three‐dimensional objects of the investigated samples. Results: Differences between physiological and abnormal parts of the leg bones are distinguishable in the CT‐images and three‐dimensional reconstructed objects. Bone density can be calculated and thus provides a base to estimate possible nutritional demands or deficiencies. The three‐dimensional reconstruction compensates for the difficulties in understanding the detailed anatomical CT cross‐sections by which the examiner is confronted while studying the CT images. Conclusion: Although computed tomography of poultry is too expensive for routine herd diagnosis, and far less for single‐animal diagnosis, it is a valuable tool for investigating skeletal abnormalities and is very useful in examining samples related to leg weakness.     

WHOLE BODY COMPUTED TOMOGRAPHIC CHARACTERISTICS OF SKELETAL AND CARDIAC MUSCULAR METASTATIC NEOPLASIA IN DOGS AND CATS

Muscular metastatic neoplasia has been reported to be rare in domestic animals, however previous studies were based primarily on necropsy findings. The purpose of this retrospective study was to describe whole body computed tomography (CT) characteristics of confirmed muscular metastases in a cohort of dogs and cats presented for oncology evaluation. Medical records of 1201 oncology patients were reviewed. Included animals underwent pre and postcontrast whole body CT, and CT‐guided tru‐cut biopsy or fine needle aspiration of one or more metastatic lesions. Twenty‐one dogs and six cats met inclusion criteria, representing 2.08% of all canine oncology patients and 3.1% of all feline oncology patients. Mean age was 9.6 years. Postcontrast CT characteristics included well‐demarcated, oval‐to‐round lesions with varying enhancement patterns: ring enhancing (n = 16), heterogeneously enhancing (n = 8), or homogeneously enhancing (n = 5). Five animals showed concurrent and varying nodular patterns. In seven cases (five dogs and two cats), one single muscular nodule was observed. In 20 cases, two or more lesions were observed. In two cases, cardiac hypodense nodules were observed in the postcontrast CT, while appearing isodense in the precontrast study. Necropsy confirmed neoplasia in both of them. Locations of muscular metastases included epaxial/paraspinal muscles of the cervical, thoracic, and lumbar spine (n = 18), superficial muscles of the thoracic wall (n = 13), scapular/shoulder region (n = 3), hind limb (n = 3), and abdominal wall muscles (n = 1). Findings supported the use of pre and postcontrast whole body CT for oncologic staging in dogs and cats, especially for primary tumors characterized by a high metastatic rate.     

Peroxisome proliferator-activated receptor-γ coactivator 1 α (PGC-1 α) expression and the formation of slow-twitch muscle fibers in porcine and bovine skeletal muscles

The peroxisome proliferator‐activated receptor‐γ coactivator‐1 α (PGC‐1 α) induces mitochondria biogenesis in skeletal muscles. To determine the relationships between PGC‐1 α and the muscle fiber types, the expression levels of PGC‐1 α were analyzed in porcine and bovine skeletal muscles. As a first step, the nucleotide sequences of the porcine and bovine PGC‐1 α were determined. The porcine and bovine PGC‐1 α cDNA encoded 796 amino acid sequences and showed 95.1% identity between the two species. The expression levels of the PGC‐1 α mRNA were analyzed in the same 10 skeletal muscles from four pigs and three cattle. The contents of porcine and bovine PGC‐1 α were higher in the tongue, masseter and diaphragm, and lower in the Biceps femoris, semimembranosus, Longissimus thoracis and semitendinosus muscles. The contents of myosin heavy chain slow‐type protein (MyHC‐slow) were also determined in the same muscles by ELISA. The analysis of MyHC‐slow showed results similar to those for the PGC‐1 α contents in all of the muscles except for the tongue. The content of MyHC‐slow in the tongue was the lowest among the porcine muscles, and moderate among the bovine muscles. The results suggest that PGC‐1 α relates to the development of oxidative muscle fibers, but is not the principal factor in determining type I fiber content.     

Polymyositis in mice experimentally inoculated with Getah virus

Mice inoculated intracerebrally with parent, large-plaque (LP) and small-plaque (SP) strains of Kanagawa strain of Getah virus showed clinically recumbency and paralysis. The LP strain caused recumbency more rapidly and killed mice more early after inoculation than the parent and SP strains. Microscopically, skeletal muscles of the whole body were involved showing degenerative or inflammatory changes. In mice inoculated with the parent or SP strains, there were degeneration and necrosis of the muscle fibers with inflammatory cell infiltration and regenerative reaction. The lesions were particularly conspicuous in muscles of the hind legs. In mice inoculated with the LP strain, most of the muscle fibers revealed degeneration and necrosis, but reactive changes were poor. In addition, the periosteum and muscular connective tissue were thickened with karyorrhexis. Electron microscopically, virus particles were recognized mainly in cisternae of sarcoplasmic reticulum in skeletal muscle fibers of mice inoculated with the LP strain, while they were rare in those of animals injected with the parent and SP strains. From these finding, it was suggested that Kanagawa strain of Getah virus has the virulence to skeletal muscles of mice.