Objective—To determine the effect of nonthermal plasma on Staphylococcus aureus, fibroblasts in monolayer culture, and clean and contaminated skin explants.
Sample Population—Normal skin from euthanized horses.
Procedures—S aureus organisms were plated and treated with nonthermal plasma followed by bacterial culture to assess viability. Fibroblasts in monolayer culture and the epidermal and dermal surfaces of clean and S aureus–contaminated skin explants were treated. The effects of distance and duration on the response to treatment were compared.
Results—Compared with controls, treatment with nonthermal plasma resulted in significantly decreased bacterial growth and significantly inhibited survival of fibroblasts in monolayer culture. When epidermal and dermal surfaces of skin explants were treated, there was no effect on production of normal fibroblasts during explant culture, except when extended exposure times of ≥ 2 minutes were used. Treatment with nonthermal plasma resulted in significantly lower bacterial counts after 24 hours of culture of S aureus–contaminated epidermis but not of dermis.
Conclusions and Clinical Relevance—Nonthermal plasma resulted in bacterial decontamination of agar and epithelium; negative effects on fibroblasts in monolayer; and no negative effects on skin explants, except at long exposure times. Use of nonthermal plasma appears safe for treatment of epithelialized surfaces, may be safe for granulating wounds, and results in decontamination of S aureus. Investigations on the effects that nonthermal plasma may have on patient tissues are indicated with a clinically applicable delivery device.
Objective—To identify the quantitative trait loci (QTL) that contribute to hip dysplasia in dogs.
Animals—192 Labrador Retrievers.
Procedures—Hip dysplasia was measured by use of the Norberg angle (NA), dorsolateral subluxation (DLS) score, and distraction index (DI). Genome-wide screening was conducted by use of 276 unique microsatellites. Linkage analysis was performed with a variance-based linear model. Logarithm of the odds (LOD) scores were reported when values were > 2.0.
Results—Canis familiaris autosomes (CFAs) 01, 02, 10, 20, 22, and 32 harbored significant QTL at LOD scores > 2.0. Among the 6 QTL, the QTL on CFA02 had not been reported to harbor QTL for hip dysplasia. The highest LOD score of 3.32 on CFA20 contributed to the second principal component of the DLS score and NA of the right hip joint. The QTL that was mapped on CFA01 (LOD score of 3.13 at 55 centimorgans) was located on the same chromosome reported to harbor a QTL for hip dysplasia in Portuguese Water Dogs and German Shepherd Dogs. In this study, CFAs 10, 20, 22, and 32 harbored QTL for hip dysplasia that have been identified in a Labrador Retriever–Greyhound pedigree and in German Shepherd Dogs.
Conclusions and Clinical Relevance—Multiple QTL were clearly involved with hip dysplasia. Identification of these QTL will enable fine-resolution mapping and subsequent assessment of candidate genes within the refined intervals to enable researchers to develop genetic screening tests and preventative and novel therapeutic regimens.
Objective—To determine the radiographic methods
that best predict the development of osteoarthritis in
the hip joints of a cohort of dogs with hip dysplasia
and unaffected dogs.
Animals—205 Labrador Retrievers, Greyhounds, and
Labrador Retriever-Greyhound crossbred dogs.
Procedure—Pelvic radiography was performed when
the dogs were 8 months old. Ventrodorsal extendedhip,
distraction, and dorsolateral subluxation (DLS)
radiographs were obtained. An Orthopedic
Foundation for Animals-like hip score, distraction
index, dorsolateral subluxation score, and Norberg
angle were derived from examination of radiographs.
Osteoarthritis was diagnosed at the time of necropsy
in dogs ≥ 8 months of age on the basis of detection
of articular cartilage lesions. Multiple logistic regression
was used to determine the radiographic technique
or techniques that best predicted development
Results—A combination of 2 radiographic methods
was better than any single method in predicting a cartilage
lesion or a normal joint, but adding a third radiographic
method did not improve that prediction. A
combination of the DLS score and Norberg angle best
predicted osteoarthritis of the hip joint or an unaffected
hip joint. All models that excluded the DLS score
were inferior to those that included it.
Conclusions and Clinical Relevance—A combination
of the DLS score and Norberg angle was the best
predictor of radiographic measures in 8-month-old
dogs to determine whether a dog would have normal
or osteoarthritic hip joints. (Am J Vet Res 2003;64:1472–1478)
Objective—To determine whether a mutation in the fibrillin 2 gene (FBN2) is associated with canine hip dysplasia (CHD) and osteoarthritis in dogs.
Procedures—Hip conformation was measured radiographically. The FBN2 was sequenced from genomic DNA of 21 Labrador Retrievers and 2 Greyhounds, and a haplotype in intron 30 of FBN2 was sequenced in 90 additional Labrador Retrievers and 143 dogs of 6 other breeds. Steady-state values of FBN2 mRNA and control genes were measured in hip joint tissues of fourteen 8-month-old Labrador Retriever–Greyhound crossbreeds.
Results—The Labrador Retrievers homozygous for a 10-bp deletion haplotype in intron 30 of FBN2 had significantly worse CHD as measured via higher distraction index and extended-hip joint radiograph score and a lower Norberg angle and dorsolateral subluxation score. Among 143 dogs of 6 other breeds, those homozygous for the same deletion haplotype also had significantly worse radiographic CHD. Among the 14 crossbred dogs, as the dorsolateral subluxation score decreased, the capsular FBN2 mRNA increased significantly. Those dogs with incipient hip joint osteoarthritis had significantly increased capsular FBN2 mRNA, compared with those dogs without osteoarthritis. Dogs homozygous for the FBN2 deletion haplotype had significantly less FBN2 mRNA in their femoral head articular cartilage.
Conclusions and Clinical Relevance—The FBN2 deletion haplotype was associated with CHD. Capsular gene expression of FBN2 was confounded by incipient secondary osteoarthritis in dysplastic hip joints. Genes influencing complex traits in dogs can be identified by genome-wide screening, fine mapping, and candidate gene screening.