Alterations to the synovial invaginations of the navicular bone are associated with pathology of both the navicular apparatus and distal interphalangeal joint when evaluated using high field MRI

Limited information exists regarding associations between distal interphalangeal joint (DIPJ) abnormalities and synovial invagination changes in the distal sesamoid (navicular) bone. This retrospective, analytical study aimed to measure specific characteristics of the synovial invaginations of the navicular bone to determine whether any single characteristic was associated with abnormalities in the DIPJ or navicular apparatus (NA) using high field MRI and a sample of 200 horses’ feet. The DIPJ and NA were graded independently by three scorers. The grades were averaged, creating a global pathology score for the DIPJ, NA, and synovial invaginations. Higher global scores represented more severe pathology. The number of invaginations, depth of penetration, invagination shape, and cross-sectional area (CSA) of the largest invagination were recorded. Interobserver agreement was measured using Cohen's Kappa. Associations of global scores of the DIPJ and NA with individual invagination characteristics were assessed using linear mixed modeling. A significant relationship was found between the number of invaginations and global DIPJ score, with higher invagination numbers associated with higher DIPJ scores. For invagination depth and CSA, a significant relationship was noted with global scores of both the DIPJ and NA. Reliable relationships between the shape of synovial invaginations and global scores of DIPJ and NA were not found, likely due to poor interobserver scoring (0.305). These findings suggest that primary DIPJ disease and NA pathology should be considered when noticing alterations to navicular synovial invaginations on MRI. This contrasts traditional views that synovial invagination abnormalities are indicative solely of NA pathology.     

Potential use of characterised hyper-colonising strain(s) of Campylobacter jejuni to reduce circulation of environmental strains in commercial poultry

Sixty-two persistently colonising Campylobacter jejuni strains were tested for their ability to dominate colonisation of the chicken gastrointestinal tract in competition with each other leading to selection of dominant or "hyper-colonising"Campylobacter strains, which are able to displace others in the chicken intestinal tract. One such strain was shown to be a hyper-efficient coloniser of chickens, as it was able to displace other colonising strains, as well as maintain itself in the chicken intestinal tract for the duration of the 56-day broiler production cycle. Once colonisation was established, this hyper-colonising C. jejuni strain, 331, could not be displaced by other colonising or hyper-colonising strains. We proposed that a defined, hyper-colonising strain, or a cocktail of defined strains with a similar phenotype, could form the basis for biological control of unknown/uncharacterised Campylobacter strains from the environment that continuously colonise chicken flocks. To validate this approach, three different chicken infection trials were carried out. These trials demonstrated that the dominant strain of C. jejuni was able to colonise broiler chickens consistently and for the entire life of the birds irrespective of the day of inoculation and antimicrobial agents used in the feed to control other pathogenic micro-organisms. In addition, we have shown that the bio-control strain was able to replace other colonising strains at various points of a 56-day broiler production cycle irrespective of time and type of inoculation. This strain was also capable of re-establishing itself following the challenge with other strains, with and without re-challenge. This work represents a "proof of principle" that a defined C. jejuni strain could be used to biologically control circulation of uncharacterised environmental strains in commercial poultry flocks.     

Structural and biophysical properties of whole leaf and root tissue and isolated cell walls of common green bean and tomato seedlings grown in an aquaponics system relative to soil-grown counterparts

Due to increased demand for high-yielding agricultural methodologies – which are both sustainable and economically viable for the local market – research on new, alternative methods has become imperative. In this paper, crops grown within an aquaponics system are compared to soil-grown counterparts to observe the changes that occur in the key structural components and energy-producing components. The growth of the plants was monitored in both systems by consistently testing photosynthetic yield, chlorophyll content, the height of the plant, and the surface area of the leaves. After the growth period was completed, the plants were harvested and tested for changes in the fine structure of the plant. The water in the aquaponics system was monitored through the growing process and remained a stable environment for both the plants and the tilapia. The soil used to grow the traditionally grown counterparts was also tested for the same components as the water in the aquaponics system. The results from these procedures were indicative of increased growth rates, biomass production in stem and roots, incorporation of nitrogen, photosynthetic output, and cell respiration, as well as changes to the fine structure of the plant cell wall. It is the hope of this initial investigation to open up further detailed investigations concerning the effect on crops grown using aquaponic-based agriculture.

     

MAGNETIC RESONANCE IMAGING FEATURES OF EXTRADURAL HEMATOMAS ASSOCIATED WITH INTER VERTEBRAL DISC HERNIATION IN A DOG

Myelography and magnetic resonance imaging (MRI) were performed on a 4-year-old neutered female Rottweiler with bilateral pelvic limb paresis. On the myelogram, there was extradural spinal cord compression at the level of the T11-12 intervertebral disc. Inadvertent placement of epidural contrast medium also allowed identification of a 1-cm circular filling defect in the epidural space dorsal to the compressed spinal cord. MRI showed partial loss of the nucleus pulposus signal of the T11-12 disc, a focal signal void within the vertebral canal at T11 compatible with a free disc fragment, and extradural masses compressing the spinal cord at T10-11 and T11-12. Hemorrhage within the masses was confirmed on T2*-weighted images. A mixture of hematoma and mineralized disc material was found at surgery, and there was no histopathologic evidence of neoplasia. In this article, the appearance on MRI of hemorrhage associated with intervertebral disc herniation is discussed.     

Implications of hypoxia tolerance for wetland refugia use in Lake Nabugabo,Uganda

Aquatic hypoxia can affect predator‐prey interactions by altering the success rate of the predator and/or the vulnerability of prey. For example, in the Lake Victoria basin of East Africa, native prey exploit hypoxic wetlands as refugia from predation by introduced Nile perch (Lates niloticus). Here, it is predicted that species exploitation of wetlands depends on their hypoxia tolerance relative to the heterogeneity of wetland hypoxia. In this study, we compared the hypoxia tolerance of four fish taxa that differ in their use of hypoxic wetlands in Lake Nabugabo, Uganda: the cichlid Pseudocrenilabrus multicolor victoriae that inhabits the dense swamp interior; and three taxa that inhabit wetland ecotones including Nile tilapia (Oreochromis niloticus), L. niloticus and juvenile endemic haplochromine cichlids. We characterised hypoxia tolerance by exposing fish to progressive hypoxia and quantifying variation in aquatic surface respiration (ASR). The effect of body size on tolerance was explored in L. niloticus by quantifying ASR behaviour across a range of size classes. ASR behaviour was also compared between O. niloticus groups from wetland versus open‐water habitats to detect habitat‐associated intraspecific variation. The most tolerant taxon was the swamp specialist P. multicolor, indicated by its low ASR thresholds and small percentage of fish using ASR during the final sample interval. The other three taxa did not differ in ASR behaviour, and no differences were detected between O. niloticus groups. Body size effects were present for L. niloticus suggesting a lower tolerance to hypoxia in larger‐bodied individuals, thus limiting their ability to penetrate wetlands.     

Treatment of biologically inactive nonunions by a limited en bloc ostectomy and compression plate fixation: a review of 17 cases

OBJECTIVE: To describe a surgical technique for treatment of biologically inactive nonunions using en bloc ostectomy and compression plate fixation and clinical outcome in 17 dogs. STUDY DESIGN: Retrospective clinical study. SAMPLE POPULATION: Seventeen dogs. METHODS: A transverse ostectomy was performed adjacent and parallel to the nonunion to eliminate nonviable tissue and provide a new, viable fracture surface with a minimum circumferential contact area of 315 degrees. With most of the bony column anatomically reconstructed, compression plate fixation was used to stabilize the fracture. Autogenous cancellous bone grafting was used if a fracture gap was present (<45 degrees of missing circumferential bone contact). Resection of bone was limited so that bone shortening was less than 20% of the overall bone length. Clinical and radiographic follow-up evaluations were obtained whenever possible. RESULTS: Complete circumferential bone contact and compression plate fixation was achieved after ostectomy in 12 dogs; cancellous bone graft was used in 5 dogs. En bloc ostectomy sites were radiographically healed in a median time of 2.5 months after surgery in 11 dogs that returned for complete in-hospital follow-up, and progressive healing was observed in 3 other dogs, where in-hospital follow-up was obtained up to 2 months after surgery. These dogs had a median follow-up time of 2 months, at which time 6 dogs had no lameness, 4 had minimal lameness, and one had moderate lameness. No complications occurred, and no implants were removed. CONCLUSIONS: En bloc ostectomy with compression plate fixation was considered successful for the treatment of biologically inactive nonunions. A good to excellent prognosis can be expected with minimal complications. CLINICAL RELEVANCE: Use of an en bloc ostectomy technique for the treatment of biologically inactive nonunions permits easy resection of nonviable tissue. Subsequent fracture stabilization with compression plate fixation resulted in rapid bone healing without complications.     

Efficacy and safety of once versus twice daily administration of methimazole in cats with hyperthyroidism

OBJECTIVE: To determine whether once daily administration of methimazole was as effective and safe as twice daily administration in cats with hyperthyroidism. DESIGN: Randomized, nonblinded, clinical trial. ANIMALS: 40 cats with newly diagnosed hyperthyroidism. PROCEDURE: Cats were randomly assigned to receive 5 mg of methimazole, PO, once daily (n = 25) or 2.5 mg of methimazole, PO, twice daily (15). A complete physical examination, including measurement of body weight; CBC; serum biochemical analyses, including measurement of serum thyroxine concentration; and urinalysis were performed, and blood pressure was measured before and 2 and 4 weeks after initiation of treatment. RESULTS: Serum thyroxine concentration was significantly higher in cats given methimazole once daily, compared with cats given methimazole twice daily, 2 weeks (3.7 vs 2.0 micro +/- g/dL) and 4 weeks (3.2 vs 1.7 microg/dL) after initiation of treatment. In addition, the proportion of cats that were euthyroid after 2 weeks of treatment was lower for cats receiving methimazole once daily (54%) than for cats receiving methimazole twice daily (87%). Percentages of cats with adverse effects (primarily gastrointestinal tract upset and facial pruritus) were not significantly different between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that once daily administration of methimazole was not as effective as twice daily administration in cats with hyperthyroidism and cannot be recommended for routine use.