Fracture repair of the distal portion of the radius by use of a condylar screw implant in an adult horse.

An 8-year-old American Quarter Horse gelding was evaluated because of an open fracture involving the left radius. The horse had fallen during training and became immediately non-weight-bearing in the left forelimb. On initial evaluation, the horse was unable to bear weight on that limb; radiography revealed a long oblique fracture of the distal metaphysis of the radius with minimal displacement of the fracture fragments. Because of the configuration of the fracture, we recommended surgical intervention with internal fixation. A condylar screw implant and 4.5-mm broad dynamic compression plate were applied to the medial and dorsolateral aspects of the radius, respectively. The horse recovered in a sling and full-limb bandage. Six months after discharge, the horse was reevaluated because of a grade 4/5 lameness in the same limb. Palpation revealed signs of severe pain over the distomedial aspect of the radius. Radiography of the left radius revealed severe osteolysis beneath the distal aspect of the condylar screw implant. Surgical removal of the medial plate was performed. Sixteen months after the initial fracture repair, the horse had returned to light training without signs of lameness. Removal of the dorsal plate may be indicated if this horse is to return to aggressive training or becomes lame in the left forelimb.     

Leishmania infantum and Neospora caninum simultaneous skin infection in a young dog in Italy.

Leishmania infantum, the agent of canine leishmaniasis in Mediterranean countries, and Neospora caninum, a recently recognized protozoal pathogen in dogs, were diagnosed in a 9-month-old Argentine Dogo dog. Both skin lesions and neurological signs were present. Histopathology of cutaneous lesions revealed a suppurative, diffuse dermatitis with numerous intracellular protozoa. Serology was positive for both L. infantum (1:640) and N. caninum (1:800). Double-label immunohistochemical staining of skin samples with hyperimmune serum from L. infantum-infected dogs was positive for protozoa within macrophages, while the polyclonal antibody specific for N. caninum showed positive reactions for protozoa in endothelial cells and fibroblasts. Transmission electron microscopy (TEM) confirmed the infection with both protozoa. This is, to the authors' knowledge, the first case of simultaneous infection with L. infantum and N. caninum in a dog. It is possible that the immunosuppressive effects of Leishmania infection or long-term steroid therapy may have been a contributing factor to the development of N. caninum in this dog.     

Ultrasonographic examination of injuries to the achilles tendon in dogs and cats.

The value of ultrasonography in the diagnosis of lesions of the Achilles tendon was Investigated in 42 dogs and seven cats. A standardised four-part ultrasonographic examination was established. Linear transducers with a frequency of more than 7.5 MHz were used. Ultrasonography allowed identification and differentiation of total ruptures and the differentiation of partial ruptures into deep or superficial ruptures, or those comprising muscular tears. The healing process could be monitored and imaged using this technique. Suture material was readily visible in surgically treated cases. Displacement of the superficial digital flexor tendon could be identified. In such cases, the tendon tissue was seen either medially or laterally to the calcaneus. The healing process of the Achilles tendon could also be documented using ultrasonography. However, it was not possible to determine the age of the injury and the exact end of the healing process. Ultrasonography therefore proved to be an excellent diagnostic method for imaging lesions of the Achilles tendon and associated injuries in dogs and cats. After physical examination, the technique should be the next logical step in the evaluation of a suspected injury to the Achilles tendon.     

Chromosome identification of the rusty-spotted cat (Felis rubiginosa): one more down and four to go

The chromosomes of the rusty-spotted cat, Felis rubiginosa, of Sri Lanka (Ceylon) were analyzed. Although the 38-chromosome complement of F rubiginosa closely resembles that of several other species, it seems to be unique with only minor variations in the D and F chromosomes. This reduces, from 5 to 4, the number of the 37 recognized world feline species not yet cytogenetically studied. Despite great differences in size and distribution, the feline species of the world are one of the most homogenous families of mammals, with only subtle chromosomal differences separating most species. By comparative cytogenetic analyses, it is becoming possible to map the probable evolutionary pathway of the world's cats.     

Electromyographic evaluation of adult Labrador retrievers with type-II muscle fiber deficiency

Labrador Retrievers with type-II muscle fiber deficiency were examined electrodiagnostically. Electromyographic changes consisted of positive sharp waves, fibrillation potentials, bizarre high-frequency discharges, and, rarely, myotonic-like discharges. Fasciculation potentials were recorded infrequently. Fibrillation potentials and bizarre high-frequency discharges were the most commonly observed electromyographic changes. Bizarre high-frequency discharges were prominent in muscles of the head and neck, proximal muscles of the thoracic limbs, and the thoracolumbar paraspinal musculature. Marked abnormalities were not observed in the motor nerve conduction velocity. Decremental responses of the evoked compound muscle action potential to repetitive nerve stimulation were not observed.     

Fate of labeled choline administered intraruminally to pregnant ewes given manganese-deficient or -supplemented rations

Tissue samples were taken from pregnant ewes and their 3-month fetuses 96 hours after intraruminal dosing of the ewes with tritiated choline. Starting 5 months before mating, one group of ewes had been given a manganese (Mn)-deficient ration and a second group had been given a Mn-supplemented (normal) ration. The results indicate that Mn depletion decreased the overall uptake of choline; the radioactivity of all tissues from the Mn-depleted group was lower than the radioactivity of the corresponding tissues from the group given a Mn-supplemented (normal) ration. The radioactivity of fetal tissues was also lower in the Mn-deficient group than it was in the Mn-supplemented group. Lower radioactivity concentrations were also observed in the whole plasma (sampled at various times after radioisotope dosing) and its lipid extract of Mn-depleted ewes than in the plasma and its lipid extract of Mn-supplemented ewes. There was no significant difference in the fatty acid composition of hepatic phosphatidyl choline between the two groups. However, the proportions of linoleic, stearic, and arachidonic acids were lower in fetal hepatic phosphatidyl choline than in maternal hepatic phosphatidyl choline.     

Identification of bovine lymphocyte subpopulations by a combined bacterial adherence and fluorescent antibody technique

It is known that certain strains of bacteria bind selectively to subpopulations of human peripheral blood lymphocytes. We have developed a technique which used the specificity of bacterial binding concurrently with fluorescent antibody staining methods to identify 5 B-cell and 5 T-cell subpopulations of bovine lymphocytes. In addition, greater than 95% of the peripheral blood lymphocytes could be positively identified as being either T-cells or B cells. Using ethidium bromide-stained bacteria and lymphocytes in combination with fluorescent antibody staining to detect surface immunoglobulins or T-cell antigens, the method provided a simple yet highly specific technique for the enumeration of both B and T cells in 1 preparation of peripheral blood lymphocytes. The use of bacterial rosetting with fluorescent antibody staining was found to be easier and more reliable than the methods currently used to identify bovine B- and T-lymphocyte subpopulations.     

Larval viability and serological response in horses with long-term Trichinella spiralis infection

The horse is considered an aberrant host for the nematode parasite Trichinella spiralis, and many aspects of the biology and epidemiology of Trichinella infection in the horse are poorly understood. It has been reported that experimentally-infected horses produce a transient serological response to infection and that muscle larvae are cleared more rapidly than in parasite-adapted hosts such as the pig and humans. However, limited numbers of animals have been studied, and both the longevity of larvae in horse musculature and the immune response to Trichinella larvae remain unclear. In this study, we infected 35 horses with 1000, 5000, or 10,000 T. spiralis muscle larvae and followed the course of infection for 1 year, assessing larval burdens in selected muscles, the condition and infectivity of recovered larvae, and the serological response of infected horses. The results demonstrated that T. spiralis establishes infection in horses in a dose dependent manner. Anti-Trichinella IgG antibodies peaked between weeks 6-10 post-inoculation. Viable, infective larvae persisted in horse musculature for the duration of the study (12 months), and exhibited no apparent reduction in muscle burdens over this period. Encapsulated larvae showed no obvious signs of degeneration in histological sections. Larval capsules were surrounded by infiltrates consisting of mature plasma cells and eosinophils. Macrophages were notably absent. Given the lack of a detectable serological response by 26 weeks p.i. and the persistence of infective muscle larvae for at least 1 year, parasite recovery methods are currently the only suitable detection assays for both meat inspection and epidemiological studies of Trichinella infection in the horse.     

Effect of acetazolamide and subsequent ventriculo-peritoneal shunting on clinical signs and ventricular volumes in dogs with internal hydrocephalus

Background

Acetazolamide is recommended for the reduction of cerebrospinal fluid production in canine internal hydrocephalus. The efficacy of the drug in terms of alleviation of the clinical symptoms and the restoration of normal ventricular volume has not been documented. We hypothesize that acetazolamide inadequately improve clinical signs and has no effect on the ventricular volume. Six dogs with internal hydrocephalus underwent neurological examination and were examined by magnetic resonance imaging, on the day of the diagnosis, after treatment with acetazolamide directly before surgery, and 6 weeks after implantation of a vetriculo-peritoneal shunt due to lack of improvement after medical therapy with 10 mg/kg acetazolamide three times daily (TID). The ventricular volume in relation to the total brain volume was determined on each occasion. The changes in relative ventricular volume and of the neurological status were assessed and compared.

Results

McNemar’s test revealed no significant differences in clinical symptoms before and after medical treatment (P > 0.05). However, clinical symptoms changed significantly after surgical treatment (P = 0.001). The ventricle-brain ratio was not significantly changed after therapy with acetazolamide (P > 0.05); however, after subsequent shunt implantation, it was significantly reduced (P = 0.001).

Conclusion

Acetazolamide (10 mg/kg TID) showed no effects on clinical signs or ventricular volume in dogs with internal hydrocephalus. After subsequent ventriculo-peritoneal shunting, the dogs had a significantly reduced cerebral ventricular volume and five out of six dogs had no abnormal findings in neurological examination.