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Abstract

Objective—To evaluate use of a diode laser to induce tendinopathy in the superficial digital flexor tendon (SDFT) of horses.

Animals—4 equine cadavers and 5 adult horses.

Procedures—Cadaveric SDFT samples were exposed to a diode laser at various energy settings to determine an appropriate energy for use in in vivo experiments; lesion size was assessed histologically. In vivo experiments involved laser energy induction of lesions in the SDFT (2 preliminary horses [0, 25, 75, and 87.5 J] and 3 study horses [0 and 125 J]) and assessment of lesions. Study duration was 21 days, and lesions were assessed clinically and via ultrasonography, MRI, and histologic evaluation.

Results—Lesion induction in cadaveric tissues resulted in a spherical cavitated core with surrounding tissue coagulation. Lesion size had a linear relationship (R 2 = 0.9) with the energy administered. Size of in vivo lesions in preliminary horses indicated that larger lesions were required. In study horses, lesions induced with 125 J were ultrasonographically and histologically larger than were control lesions. At proximal and distal locations, pooled (preliminary and study horses) ultrasonographically assessed lesions were discrete and variable in size (mean ± SEM lesion percentage for control lesions, 8.5 ± 3%; for laser lesions, 12.2 ± 1.7%). Ultrasonography and MRI measurements were associated (R 2 > 0.84) with cross-sectional area measurements.

Conclusions and Clinical Relevance—In vivo diode laser–induced lesions did not reflect cadaveric lesions in repeatable size. Further research is required before diode lasers can reliably be used for inducing tendinopathy.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess genomic sequence conservation and variation in the proviral promoter of enzootic nasal tumor virus (ENTV) and Jaagsiekte sheep retrovirus (JSRV) in tissue samples from 3 sheep with nasal adenocarcinoma associated with ENTV and 3 sheep with pulmonary adenocarcinoma associated with JSRV and to identify a cell culture system that supports transcriptional activity of the ENTV and JSRV viral promoters.

Animals—6 adult sheep.

Procedures—Standard PCR procedures for detection of the ENTV and JSRV long terminal repeat (LTR) promoter region were performed on samples from the 3 nasal adenocarcinomas and 3 pulmonary adenocarcinomas, respectively. The LTRs were cloned into shuttle vectors, amplified, sequenced, and analyzed. The cloned LTR regions were transferred into reporter plasmids and multiple human and ruminant cell lines, and primary cells were transfected with the promoter-reporter plasmids. The viral promoter activity was evaluated by use of an in vitro β-galactosidase reporter assay.

Results—Each isolate had a unique nucleotide sequence. Single nucleotide polymorphisms were the most common LTR mutation and rarely occurred at transcription factor binding sites. Relative to ENTV, the JSRV promoter isolates had a conserved 66-bp U3 insertion, including the lung-specific transcription factor HNF-3β binding site. Among the cell lines used, human embryonic kidney (293T) and goat synovial membrane cells supported promoter transcription.

Conclusions and Clinical Relevance—The LTRs of ENTV and JSRV have extensive blocks of sequence conservation. Human 293T and goat synovial membrane cell lines may be suitable in vitro cell culture systems for further research of viral promoter functions.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

The aim of this study was to assess the efficacy and safety of a third-generation lentivirus-based vector encoding the feline erythropoietin (EPO) (feEPO) gene in vitro and in rodent models in vivo. This vector incorporates a genetic mechanism to facilitate the termination of the therapeutic effect in the event of supraphysiologic polycythemia, the herpes simplex virus thymidine kinase (HSV-TK) “suicide gene.”

ANIMALS

CFRK cells and replication-defective lentiviral vectors encoding feEPO were used for in vitro experiments. Eight Fischer rats were enrolled in the pilot in vivo study, 24 EPO-deficient mice were used in the initial mouse study, and 15 EPO-deficient mice were enrolled in the final mouse study.

METHODS

Efficacy of a third-generation lentivirus encoding feEPO was determined in vitro using western blot assays. Subsequently, in a series of rodent experiments, animals were administered the viral vector in progressively increasing inoculation doses with serial measurements of blood packed cell volume (PCV) over time.

RESULTS

We documented production of feEPO protein in transduced CRFK cells with subsequent cessation of production when treated with the HSV-TK substrate ganciclovir. In vivo, we demonstrated variably persistent elevated PCV values in treated rats and mice with eventual return to baseline values over time.

CLINICAL RELEVANCE

These results provide justification for a lentiviral gene therapy approach to the treatment of nonregenerative anemia associated with chronic renal disease in cats.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To determine the clinical features, treatment, and outcomes of treatment for oral and cutaneous squamous cell carcinoma (SCC) in avian species.

DESIGN Retrospective case series with nested cohort study.

ANIMALS 87 client-owned birds of various species with histologically confirmed SCC of the skin or oral cavity.

PROCEDURES Clinicians entered case information through an online survey tool. Data were collected regarding patient signalment, concurrent conditions, treatments, adverse effects, and clinical outcomes. Relationships were examined between complete excision and partial or complete response. Survival analysis was performed to compare outcomes among groupings of therapeutic approaches.

RESULTS Only 7 of 64 (11%) birds for which full outcome data were available had complete remission of SCC; 53 (83%) had progressive disease, were euthanized, or died of the disease. The unadjusted OR for partial or complete response following complete tumor excision (vs other treatment approaches) was 6.9 (95% confidence interval [CI], 1.8 to 25.8). Risk of death was 62% lower (hazard ratio, 0.38; 95% CI, 0.19 to 0.77) for birds that underwent complete excision versus conservative treatment. Median survival time from initial evaluation for birds receiving complete excision was 628 days (95% CI, 210 to 1,008 days), compared with 171 days (95% CI, 89 to 286 days) for birds receiving monitoring with or without conservative treatment. Birds receiving any other additional treatment had a median survival time of 357 days (95% CI, 143 to 562 days).

CONCLUSIONS AND CLINICAL RELEVANCE For birds with SCC, complete excision was the only treatment approach significantly associated with complete or partial response and increased survival time.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Case Description—A 1.5-year-old spayed female Bernese Mountain Dog was examined for a 6-month history of intermittent vomiting, regurgitation, wheezing, and coughing. Initially, a diagnosis of gastroesophageal reflux disease with secondary aspiration pneumonitis was made but clinical signs did not resolve with treatment.

Clinical Findings—Thoracic and cervical radiography and CT revealed a sessile, irregularly marginated soft tissue opacity at the level of the fourth rib. Results of a CBC, serum biochemical analysis, and urinalysis were within reference limits. Results of abdominal ultrasonography were normal.

Treatment and Outcome—Tracheoscopy revealed a firm, irregularly marginated mass apparently originating from the ventral aspect of the trachea, occluding approximately one-half of the tracheal lumen, and located 2 cm cranial to the carina. Cytologic and histopathologic examination of fine-needle aspirate and biopsy samples suggested a benign etiology; therefore, endoscopic minimally invasive laser and electrocautery resection of the mass was scheduled. A total IV anesthetic protocol was administered with an oxygen-air mixture used to decrease the risk of fire during tracheal surgery. The mass was successfully resected, and histopathologic examination confirmed a diagnosis of osteochondroma. Clinical signs resolved, and at follow-up 32 months later, no regrowth of the mass was evident.

Clinical Relevance—Tracheoscopy-guided electrocautery and surgical diode laser resection was successful in removing an obstructive tracheal mass that was not resectable by means of a conventional open surgical approach. Minimally invasive procedures may decrease morbidity and mortality and improve outcome in appropriately selected small animal patients.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To characterize clinical and pathological features of implant-associated neoplasms in dogs.

Design—Retrospective case-control study.

Animals—16 dogs with implant-associated neoplasia and 32 control dogs with osteosarcoma without implants.

Procedures—Medical records of dogs with tumors associated with metallic implants (cases) treated between 1983 and 2013 were reviewed. Two dogs with naturally occurring osteosarcoma (controls) were matched to each case on the basis of tumor location, age, and sex.

Results—Median time from implant placement to diagnosis of neoplasia was 5.5 years (range, 9 months to 10 years). Pelvic limbs were most frequently affected, including the tibia (8/16) and femur (5/16), with 1 neoplasm involving both the femur and pelvis. Implant-associated tumors most commonly affected the diaphysis (15/16), with osteosarcomas significantly more likely to involve the long bone diaphysis in case dogs than in control dogs with naturally occurring osteosarcomas. Osteosarcoma was the most common tumor, accounting for 13 of 16 implant-associated tumors. For 7 of these osteosarcoma cases, review of histopathology results enabled subclassification into osteoblastic nonproductive (n = 3), chondroblastic (2), osteoblastic productive (1), and fibroblastic (1) groups. Three case dogs had a diagnosis of histiocytic sarcoma, fibrosarcoma, and spindle cell sarcoma.

Conclusions and Clinical Relevance—Results of this study highlighted important anatomic differences between spontaneous and implant-associated neoplasia in dogs. (J Am Vet Med Assoc 2015;247:778–785)

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To describe clinical, imaging, gross, and histopathological abnormalities associated with osteochondral necrosis of the femoral condyles in foals and identify features suggestive of a common pathogenesis.

ANIMALS

8 Thoroughbred foals euthanized with a presumptive diagnosis of necrosis of the femoral condyles.

PROCEDURES

Postmortem CT was performed on all distal femoral epiphyseal samples. The articular epiphyseal cartilage complex (AECC) of affected distal femurs was examined grossly and histologically, focusing on lesions of interest identified on CT images.

RESULTS

7 foals were between 9 and 23 days old at the time of euthanasia; 1 foal was 85 days old. Concurrent illness (neonatal maladjustment syndrome, neonatal isoerythrolysis, or infection such as enteritis and omphalitis) was diagnosed in 7 foals. The characteristic antemortem radiographic and postmortem CT finding was a crescent-shaped osteochondral flap displaced from the affected medial femoral condyle. Synovial fluid cytology from affected joints was either within normal limits or consistent with mild inflammation. Histologically, all lesions were characterized by osteochondral necrosis and detachment of the AECC. In 6 foals, polymorphonuclear cells were found within growth cartilage canals, representing septic cartilage canals.

CLINICAL RELEVANCE

Osteochondral necrosis was interpreted to be secondary to bacterial colonization of the distal femoral AECC, evidenced by septic cartilage canals identified in 6 of 8 foals. This uncommon condition was previously thought to arise from an ischemic event, but the disease process was not well understood. An improved understanding of the pathogenesis of osteochondral necrosis is the first step in formulating more successful preventative and treatment strategies.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To describe clinical features of oral and maxillofacial osteomas in cats.

Design—Retrospective case series.

Animals—7 cats with oral or maxillofacial osteoma or both.

Procedures—Medical records were reviewed for information on signalment, history, clinical signs, physical examination findings, diagnostic imaging findings, results of serum biochemical analyses and histologic testing, surgical procedures performed, and perioperative complications. Outcome was determined on the basis of follow-up telephone interviews of owners.

Results—Cats ranged from 1 to 23 years of age. Clinical signs were observed in 5 cats and were attributed to the presence of the mass. Diagnostic imaging (radiography and computed tomography) and histologic examination confirmed the diagnosis of osteoma. Three cats were euthanatized; 1 cat was treated by mandibulectomy, 1 was treated by maxillectomy, and 2 were treated by debulking. At the time of follow-up at least 1 year after surgery, all 4 treated cats were alive, with owners reporting an acceptable quality of life.

Conclusions and Clinical Relevance—Osteoma of the oral and maxillofacial regions is an uncommon tumor in cats. Most cats are examined during an advanced stage of the disease, when treatment options may be limited. Although osteoma is a benign tumor, the recommendation is to perform a clinical evaluation, diagnostic imaging, biopsy, and treatment early in the disease process, when less invasive surgical approaches may be feasible.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify risk factors associated with survival in dogs with nontonsillar oral squamous cell carcinoma (OSCC) that were and were not treated with curative-intent surgery.

Design—Retrospective case series.

Animals—31 dogs with OSCC.

Procedures—Medical records for dogs with OSCC that were not treated, or were treated with curative-intent surgery only between January 1990 and December 2010 were reviewed. For each dog, data regarding signalment, clinical stage, treatment, tumor recurrence, and survival time were obtained from the medical record, and archived biopsy specimens were evaluated to identify the histologic subtype of the tumor and extent of tumor-associated inflammation (TAI), perineural invasion (PNI), and lymphovascular invasion (LVI).

Results—Risk of death for the 21 dogs with OSCC that were surgically treated was decreased 91.4% (hazard ratio, 0.086; 95% confidence interval, 0.002 to 0.150), compared with that for the 10 dogs with OSCC that were not treated. The 1-year survival rate was 93.5% and 0% for dogs that were and were not surgically treated, respectively. Risk of death increased significantly with increasing TAI and increasing risk score (combination of TAI, PNI, and LVI). Tumor location, clinical stage, and histologic subtype were not associated with survival time.

Conclusions and Clinical Relevance—Results indicated that the prognosis for dogs with OSCC was excellent following surgical excision of the tumor. Risk of death increased with increasing TAI, and combining TAI, PNI, and LVI into a single risk score may be a useful prognostic indicator for dogs with OSCC.

Full access
in Journal of the American Veterinary Medical Association