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At least 19 recordsLinked to original sources

Comparative analysis of weight gain, hand/wrist maturation, and dental emergence rates in chimpanzees aged 0-24 months from varying captive environments.

Variability during the first 2 years of growth and development is examined in captive chimpanzees. The mixed longitudinal study of 175 animals compares curves of weight, hand/wrist maturation, and dental emergence for groups within the sample which differ in sex, rearing circumstances (mother-reared versus hand-reared), and colony (Primate Foundation of Arizona, White Sands Research Center, and The University of Texas M.D. Anderson Cancer Center Department of Veterinary Sciences in Bastrop, Texas). Comparison of LOWESS fits of the curves, using a conservative jack-knife approach, reveals trends toward significant differences between colonies for weight (with 4 comparisons reaching significance) and between rearing groups for maturation (1 reaching significance). Results of a full versus reduced model approach show the same trends, for which significance is reached in a higher number of comparisons. The latter approach also indicates possible effects of sex and environmental differences on dental emergence rate. Difficulties with both approaches are discussed. It is concluded that the results are suggestive of significant sex and environmental effects on the variables monitored, justifying further analysis and continuation of the study. The study is significant in 1) providing norms specific to sex and rearing and colony environments with which individual colony animals may be compared in the assessment of their development and in 2) providing a standard, based upon data from a larger and more varied captive chimpanzee population than previously available, with which the dental emergence status and hand/wrist maturation of fossil apes and hominids may be compared.

Aging↗

Morphogenesis of the carpal elements in the regenerating forelimb of adult Notophthalmus viridescens viridescens.

This study is concerned with the morphogenesis of the carpal elements in the regenerating forelimb of the adult newt. Blastema cells surrounding the remnant bony stumps begin to differentiate into cartilage on the twentieth post-amputation day. Subsequently, masses of carilage build up from the radial and ulnar stumps. The radial mass is larger and differentiates more rapidly than the ulnar mass. By the fifty-fifth post-amputation day, the eight basic carpal elements are formed, with fusion of two of the units, intermedium with ulmare, occurring by the seventieth day. The completed regenerate possesses the seven carpal elements characteristic of the normal adult limb. The present results show that during limb regeneration in the adult newt the carpal elements are restored to their original number and position and that the pattern of such carpal differentiation proceeds in a proximodistal direction influenced by the stump remnants of the radius and ulna.

Animals↗

Detailed anatomy of the antebrachiocarpal joint in dogs.

A comparative study of the anatomy of the antebrachiocarpal (AC) articulation was carried out in 30 adult dogs with 60 joints. Although a considerable degree of similarity was found between the AC joint in dogs and the corresponding wrist joint in humans, a number of differences between these two homologous joints were also noted. The distal end of the ulna in dogs directly articulates with the ulnar carpal and accessory carpal bones forming a specialized antebrachiocarpal arrangement more adapted to running. The accessory carpal bone in dogs is a massive, long bone and is strikingly different from its homologue in humans, the pisiform bone. The joint between the accessory and ulnar carpal bones, which corresponds to the piso-triquetral joint in humans, is always connected with the AC joint, whereas in humans this communication could be found occasionally. The large radial carpal bone in dogs, characteristic for carnivores, corresponds to the fused scaphoid and lunate bones in humans, in whom this type of fusion is very rarely found. The palmar ulnocarpal and radiocarpal ligaments in dogs are distinctly intra-articular, whereas in humans these ligaments are intracapsular. One of the controversies of the AC joint in dogs is a structure located between the distal-most parts of the radius and ulna forming a strong bond between these two bones and a part of the antebrachial articular surface. It is cartilage-like and is composed of typical fibrocartilaginous tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Iodide and albumin kinetics in normal canine wrists and knees.

The clearance rates of free iodide and of radioiodinated serum albumin were measured in the knee and wrist joints of 9 normal adult dogs. Iodide clearance from the knee was 3 times greater than that from the wrist. In contrast, radioiodinated serum albumin clearance from the knee was only slightly greater than that from the wrist. Interpreted as respective indices of effective synovial plasma flow and lymphatic drainage, these values indicate that the filtration fraction is normally greater in microvessels of the wrist than in those of the knee. These findings complement the results of companion studies of Starling forces that indicate a higher pressure microvascular bed in the wrist than in the knee.

Animals↗

Hydrostatic and oncotic determinants of microvascular fluid balance in normal canine joints.

Water moves between plasma (p) and synovial fluid (SF) in response to gradients in the balance of opposing hydrostatic pressures (HP) and oncotic pressures (OP). At the vascular site where proximal filtration ceases and distal reabsorption begins, all forces are theoretically in balance. At this point, the transitional microvascular pressure (TMP) may be estimated from the equation TMP = HPSF + OPP - OPSF. We measured these forces in the shoulders, wrists, and knees of 10 normal dogs, ages 2-10 years. The mean HPSF in the knee was lower than that in the shoulders and significantly lower than that in the wrist. Conversely, the OPSF in the wrist was significantly lower than that in the shoulder or the knee. These factors combined indicate that the microvascular bed in the normal knee has a remarkably low mean TMP (7.9 mm Hg). We also found a strong positive correlation between the age of each dog and the mean oncotic pressure of its SF.

Animals↗

Biomechanical properties of third carpal articular cartilage in exercised and nonexercised horses.

The relevance of site and exercise on the biomechanical properties of the articular cartilage from the equine third carpal bone were assessed by creep indentation testing. Six horses were exercised for 30 minutes three times weekly. Another six horses were housed in box stalls and were not exercised. At the conclusion of the study, one third carpal bone from each horse was harvested and the KLM biphasic material properties of cartilage were determined at 12 sites. There was a significant (p < 0.01) effect of site but not exercise on the cartilage aggregate modulus, which was significantly lower for sites on the dorsal aspect of the radial facet and for all sites on the intermediate facet as compared with sites on the palmar aspect of the radial facet of the third carpal bone. Exercise significantly increased the permeability constant at all sites when compared with the nonexercised group, but there was no difference between sites within groups. Exercise also significantly increased Poisson's ratio, but only at sites located on the palmar aspect of the radial facet. In general, both site and exercise influence the biomechanical behavior of third carpal articular cartilage. Inherent differences in cartilage biomechanical properties within a joint correlate with the location specificity of cartilaginous lesions in the equine midcarpal joint.

Analysis of Variance↗

IL-1 beta induces the degradation of equine articular cartilage by a mechanism that is not mediated by nitric oxide.

Proteoglycan degradation was induced in young equine articular cartilage explants cultured for eight days in the presence of 50 ng/ml recombinant human interleukin-1 beta. Degradation was initiated after 6 hours of exposure to the cytokine. This was accompanied by an induction of nitric oxide synthesis and a decrease in the incorporation of [36S]sulphate into the glycosaminoglycan chains of proteoglycans. The addition of 1mM N-iminoethyl-L-ornithine (an inhibitor of nitric oxide synthase) to the explant cultures in the presence of rhIL-1 beta suppressed the synthesis of NO and restored proteoglycan synthesis to control levels. However, treatment of explants with LNIO did not overcome proteoglycan degradation. These results indicate that although IL1 beta regulates both proteoglycan synthesis and degradation in equine cartilage explants, only the inhibition of proteoglycan synthesis is mediated by nitric oxide.

Animals↗

Healing of the articular disc of the wrist in dogs.

The healing potential of the articular disc of the wrist (antebrachiocarpal) joint was investigated in 30 adult dogs (35 joints). In 28 joints a complete section of the entire disc was carried out and sutured in 10; a partial lesion was made in 7. The dogs were killed at varying intervals from 2 weeks to 8 months and healing studied by naked eye inspection and histological examination. At 3, 6 and 8 months the tears in all specimens were completely healed by mature fibrous tissue containing fibrocartilaginous elements, whether or not they had been sutured. In peripheral areas the defect was filled by an ingrowth of young fibroblastic tissue arising from the synovium, whereas in the central areas the repair appeared to originate from neighbouring bone. We have demonstrated the ability of the mostly avascular disc to repair itself. Suturing did not enhance the healing process.

Animals↗

Postural responses of forelimb extensors to somatosensory signals elicited during wrist rotation: interaction with vestibular reflexes.

The responses of the forelimb extensor triceps brachii (TB) to sinusoidal wrist rotation, at 0.156 Hz, +/-5 degrees, were investigated in decerebrate cats. In most of the tested muscles [12/15) the multiunit electromyographic (EMG) activity of the TB muscle increased during dorsiflexion and decreased during plantar flexion of the ipsilateral limb extremity, showing an average (+/-SD) gain of 1.38+/-0.64 impulses/s/ degrees and a phase lead of 33+/-19 degrees with respect to the extreme dorsiflexion of the forepaw. Both parameters remained unmodified by increasing the amplitude of stimulation from 5 degrees up to 10 degrees. Rotation of the contralateral wrist had no effect on TB activity. When the rotation of the ipsilateral wrist occurred during sinusoidal roll tilt of the whole animal, a stimulus that activates vestibular receptors, the TB response to combined stimulation closely corresponded to the vectorial sum of the individual responses. Dorsiflexion of the forepaw could drive the vestibulospinal system, which excites the ipsilateral TB motoneurons. In fact, functional inactivation of the cerebellar anterior vermis, which controls vestibulospinal neurons, significantly modified the TB response to wrist rotation. It appears, therefore, that the somatosensory signals elicited by wrist rotation utilize the spinocerebellum to modulate the activity of the TB. The TB responses to wrist rotation could play a role in stabilizing posture during stance and locomotion.

Animals↗

Median nerve neurotization by peripheral nerve grafts directly implanted into the spinal cord: anatomical, behavioural and electrophysiological evidences of sensorimotor recovery.

Over the years, peripheral nerve grafts, a favorable environment to support axonal elongation, have given rise to increasing interest as a possible solution for promoting spinal cord repair. In the experiments described here, following an avulsion injury of the rat brachial plexus, the median nerve was repaired by a peripheral nerve graft (PN) inserted directly into the dorsal side of the spinal cord. Eight months later the animals were submitted to behavioral tests, electrophysiological and histological studies. Regrowth of axons from both motoneurons and ganglionic neurons was demonstrated following a single superficial dorsal implantation of a PN. Sensorimotor peripheral reinnervation allowed most of the studied animals to recover enough flexor activity for grasping. Reinnervation was achieved even without prior root avulsion suggesting that the presence of a PN is sufficient to induce sprouting in the spinal cord from axotomized and non-axotomized neurons.

Animals↗

Immunogenic potential of carpal implants.

This study investigated whether a cellular or a humoral-mediated immunologic response to silicone carpal prostheses could be detected in animals previously sensitized to silicone. Silicone carpal prostheses were emulsified in Freund's complete adjuvant (FCA). This emulsion was injected into guinea pigs weekly for 6 weeks. Controls received only FCA. Four weeks later a carpal prosthesis was implanted. Histology showed the implanted prosthesis encapsulated by fibrous tissue in sensitized animals, with a mononuclear infiltrate within the fibrous periprosthetic capsule consistent with a cellular immune response. Skin testing of the sensitized animals showed a true correlate response to the silicone antigen challenge, whereas no response was observed in the control group. The passive cutaneous anaphylaxis reaction in sensitized animals was positive, emphasizing that the antigen-antibody response was passively transferred. Tissue adjacent to the silicone implant in sensitized animals revealed an IgG deposition around the silicone particles by the fluorescent antibody technique. Control animals showed none of these reactions. These results indicate that microparticulate matter from carpal implants can possibly initiate both a cellular immunologic response and the production of a circulating antibody.

Animals↗

Dorso-medial ante-brachiocarpal luxation with radio-ulna luxation in a domestic shorthair.

An 8-year-old domestic shorthair was admitted with non-weight bearing left forelimb lameness. Examination and radiographs revealed dorso-medial ante-brachiocarpal luxation with palmar luxation of the distal radio-ulnar joint. Primary repair was performed and stabilised using an arthrodesis wire and type Ia Kirschner-Ehmer (K-E) external skeletal fixator (ESF). The cat regained excellent pain-free limb function by 14 weeks with only minor reduction in range of movement. This is the first case report of a cat with distal radio-ulnar joint luxation associated with ante-brachiocarpal luxation. Primary repair of carpal luxation in the cat should be considered before arthrodesis.

Animals↗

The mole's thumb -- evolution of the hand skeleton in talpids (Mammalia).

Osteological specimens representing 15 out of the 16 currently recognized talpid genera were examined and scored for seven discrete morphological characters of the hand. The phylogenetic distribution of these characters was studied in the context of alternative hypotheses of talpid relationships, using three species of shrews and a hedgehog as outgroups. All talpids show a similar number and arrangement of carpal bones. The most obvious differences concern the presence of additional sesamoid bones, the relative size of the os falciforme when present, and the degree of fusion of the scaphoid and lunate in the proximal carpal row. Marked differences in the relative length and proportions of the metacarpals also exist. The development of the carpals in Talpa europaea was studied through examination of histological sections of the hand of an embryo and a neonate. Whereas carpal anatomy in the neonate mirrors the arrangement and proportions of the adult, in the embryo the scaphoid and lunate are still separate, there are no signs of the os falciforme, and the size proportions of metacarpals to carpals are obviously different to those of the adult. A prehallux or tibial sesamoid, serial homologue to the os falciforme or prepollex (a radial sesamoid), does not have an obvious functional role, and its presence might be the result of a common epigenetic control in the hand and the foot resulting in a non-adaptive structure in the latter.

Animals↗

A joint myxoma in a dog.

Myxomas of the joints are extremely rare in domestic animals, only four cases, all in dogs, having been reported previously. This paper describes a myxoma originating from the synovium of the right radiocarpal joint of a mature female Dobermann pinscher with right front limb lameness. The tumour was excised surgically and no recurrence was detected during a 2-year follow-up period. Immunohistochemically, the tumour cells reacted with antibodies to vimentin and S100 protein but not with antibodies to cytokeratins (high and low molecular weight) or human callus keratin.

Animals↗

Biochemical composition of equine carpal articular cartilage is influenced by short-term exercise in a site-specific manner.

UNLABELLED: It was hypothesized that cartilage macro-molecular characteristics are influenced by exercise intensity and by location within a joint. OBJECTIVE: To determine the macromolecular characteristics of carpal articular cartilage at common and uncommon sites of pathology in horses undergoing high or low intensity exercise, and to compare this composition between exercise groups. DESIGN: Twelve horses (19.3+/-0.9 years) were assigned to exercise groups. Each group underwent 19 weeks high-intensity treadmill training (N=6) or low-intensity exercise (N=6). Dorsal and palmar test sites were identified on radial, intermediate and third carpal articular surfaces after euthanasia. Cartilage was collected from each site, freeze-dried and assessed for water content. Hydroxyproline, glycosaminoglycan and DNA analyses were performed on cartilage from each test site. Adjacent cartilage underwent histological preparation and assessment for chondrocyte numerical density at each site and proteoglycan distribution through the depth of cartilage. RESULTS: Dorsal cartilage had a higher collagen content, DNA content, and chondrocyte numerical density, but lower glycosaminoglycan content than palmar cartilage. Cartilage from horses undergoing high-intensity training had a significantly higher glycosaminoglycan content than cartilage from horses undergoing low-intensity exercise, with maximal difference being observed in cartilage from dorsal radial and dorsal intermediate carpal articular surfaces. Overall no effect of exercise on collagen was observed, but at sites predisposed to clinical lesions cartilage from horses undergoing high-intensity training contained significantly less collagen than from horses undergoing low-intensity exercise. Distribution of proteoglycan was non-uniform in 52% of the sections examined, with superficial loss of toluidine blue staining primarily at dorsal sites and in the high-intensity exercise group. CONCLUSIONS: These results indicate that topographical and exercise related differences exist in carpal cartilage composition, and that the effect of exercise on overall composition and distribution within the cartilage was maximal at sites predisposed to clinical lesions. These findings could indicate that the combined effect of exercise and local load variations within a joint may lead to a risk of exceeding the physiologic threshold at high load sites that are predisposed to clinical injury.

Animals↗

Concurrent use of a medial saphenous fasciocutaneous free tissue flap and external skeletal fixation for treatment of a distal antebrachial injury in a dog.

OBJECTIVE: To report the surgical management of a traumatic distal antebrachial wound using a medial saphenous fasciocutaneous free tissue flap and a type I external skeletal fixator (ESF). STUDY DESIGN: Case report. ANIMALS: A 7-year-old spayed, female Labrador retriever. RESULT: Wound coverage and pancarpal arthrodesis were accomplished during a single anesthetic episode using a medial saphenous fasciocutaneous free tissue flap and type I ESF. A second surgical procedure was performed to expedite healing of part of the original wound that was initially left to heal by second intention. CONCLUSIONS: Free tissue transfer can be used in combination with an ESF for repair of distal antebrachial wounds, allowing orthopedic repair and soft tissue coverage in a single anesthetic episode. CLINICAL RELEVANCE: Concurrent use of free tissue transfer and carpal arthrodesis with an ESF could be used for repair of complex antebrachial wounds without need for multiple procedures, extended hospitalization, and increased cost.

Accidents, Traffic↗

Histopathological findings in the medial palmar and dorsomedial intercarpal ligaments of the equine midcarpal joint.

Medial palmar intercarpal ligaments (MPICL) and dorsomedial intercarpal ligaments (DMICL) from the midcarpal joints of 11 adult horses in training were examined histopathologically. These were compared with ligaments from seven horses less than 12 months of age, and 10 grossly enlarged DMICLs of adult horses. Tearing of the MPICL was observed in 15 of 22 joints from adult horses. Collagen fibre bundles of the MPICLs generally were disorganized and poorly aligned, and there were large areas of loose connective tissue. In young horses there was more parallel alignment of collagen bundles and less loose connective tissue. Collagen bundles of adult DMICLs were well organized and showed parallel alignment, whereas in foals the structure appeared more like that of fibrous joint capsule. Grossly enlarged DMICLs in adults consistently had discrete areas of fibrovascular infiltration. Degeneration of the MPICL was associated with increasing age and could explain the high incidence of tearing of the ligament. Enlargement of the DMICL was associated with low-grade tearing and repair.

Aging↗

The distribution of cartilage oligomeric matrix protein (COMP) in equine carpal articular cartilage and its variation with exercise and cartilage deterioration.

Based on previous studies where tendons receiving the most load have been shown to have the highest levels of cartilage oligomeric matrix protein (COMP), we hypothesized that COMP distribution in articular cartilage may be influenced by mechanical loading. This investigation aimed (a) to describe the pattern of COMP immunoreactivity in middle carpal joint cartilage of two-year-old Thoroughbred horses; (b) to determine topographical variations; (c) to compare high (group 1) and low (group 2) intensity training and (d) to describe COMP immunoreactivity at sites with early osteoarthritis. Group 1 (n =6) underwent a 19 week high-intensity treadmill training programme and group 2 (n =6) were given daily walking until euthanasia. Dorsal and palmar sites on radial and third carpal articular surfaces were prepared. Immunohistochemistry was performed with polyclonal rabbit anti-equine COMP antiserum using a biotin-streptavidin/peroxidase method. Results showed: (a) intracellular immunoreactivity was present in all cartilage zones, but the distribution of COMP staining within the matrix varied between cartilage zones; (b) differences in distribution between sites were not observed, but total COMP levels in exercised horses (n =2) did vary between sites with dorsal sites containing less COMP than palmar sites on the radial, intermediate and third carpal lateral facet; (c) group 1 cartilage showed marked interterritorial distribution in the deep layer compared to group 2 where staining was more generalized throughout the matrix and (d) fibrillated cartilage showed increased local immunoreactivity in the matrix. These findings demonstrate zonal variations in equine COMP distribution which may be influenced by loading.

Animals↗