Cassie N. Lux

Photodynamic therapy against common bacteria causing wound and skin infections

Photodynamic therapy (PDT) uses the combination of a photosensitising (PS) agent and visible light. Historically, various injectable PS agents have been used with medical grade lasers to treat neoplasia. The objective of this in vitro study was to determine whether PDT using topical aminolevulinic acid (ALA) with a non-coherent light source would kill common wound infecting bacteria, namely, Staphylococcus intermedius, Streptococcus canis, Pseudomonas aeruginosa, and Escherichia coli. Bacterial strains were sensitised to light with ALA before exposing to the non-coherent light source. Colony counts were performed in triplicate and compared to controls. When compared with controls there was a significant decrease in bacterial survival following PDT for all organisms except E. coli. A single treatment required 2-3h of light exposure. These data suggest that PDT may be a possible treatment option for wound infections but repeated treatments or alterations in the PS or its carrier will be needed to decrease treatment times.

Perioperative outcome in dogs with hemoperitoneum: 83 cases (2005–2010)

OBJECTIVE To characterize the clinical course of dogs with hemoperitoneum in the perioperative setting and to determine risk factors that may affect short-term outcome. DESIGN Retrospective case series. ANIMALS 83 client-owned dogs. PROCEDURES The medical records of dogs with hemoperitoneum that underwent surgery between 2005 and 2010 were reviewed. Data were analyzed to determine risk factors associated with perioperative outcome. The perioperative period was defined as the time from admission to the hospital for treatment of hemoperitoneum until the time of discharge or euthanasia (within the same visit). RESULTS 13 of 83 (16%) dogs died or were euthanized in the perioperative period. The median hospitalization time for surviving dogs was 2 days (range, 1 to 5 days). The requirement for a massive transfusion with blood products was a negative prognostic indicator for hospital discharge. The source of bleeding was isolated to the spleen in 75 of 83 (90%) dogs; a splenic source of hemorrhage was determined to be a positive predictor of survival to discharge from the hospital. CONCLUSIONS AND CLINICAL RELEVANCE In the present study, factors associated with death and failure to be discharged from the hospital included tachycardia, a requirement for massive transfusion with blood products, and the development of respiratory disease secondary to suspected pulmonary thromboembolism or acute respiratory distress syndrome. The presence of disease within the spleen was positively associated with survival to discharge. Surgical intervention for treatment of hemoperitoneum, regardless of etiology, resulted in discharge from the hospital for 70 of the 83 (84%) dogs in this series.

Gastroesophageal reflux and laryngeal dysfunction in a dog

CASE DESCRIPTION A 7-year-old neutered male Saint Bernard was evaluated because of a 6-month history of coughing, gagging, change in phonation, excessive panting, and chronic intermittent vomiting and diarrhea. CLINICAL FINDINGS Physical examination revealed no remarkable findings other than panting. Total thyroxine concentration and results of a CBC, serum biochemistry analysis, urinalysis, and thoracic radiography were within reference limits. A laryngeal examination revealed edema, erythema, and ulceration of the larynx and pharynx, with normal laryngeal movement. Results of bronchoscopy and cytologic examination of bronchoalveolar lavage fluid were diagnostic only for distal tracheitis. Esophagoscopy and an esophagography revealed esophagitis consistent with gastroesophageal reflux. Gastroduodenoscopy and histologic examination of biopsy specimens revealed Helicobacter colonization and lymphocytic or plasmacytic enteritis. TREATMENT AND OUTCOME Following treatment for gastroesophageal reflux and suspected Helicobacter infection with combination antacid and antimicrobial treatment, the dogs respiratory signs resolved but vomiting continued. Gastroduodenoscopy revealed complete resolution of the previous laryngitis, pharyngitis, and esophagitis. Treatment for the lymphocytic or plasmacytic enteritis was initiated with prednisone (1 mg/kg [0.45 mg/lb], p.o., q 12 h) and a novel protein diet. The previous treatment was also continued. Complete resolution of clinical signs was maintained 4 months after initiation of appropriate treatment. CLINICAL RELEVANCE Laryngeal dysfunction induced by gastroesophageal reflux as occurred in the patient described in this report is a previously undocumented association in the veterinary literature. This association could be a potential consideration in dogs with concurrent respiratory and gastrointestinal signs. The present report may provide a basis for further studies investigating this association.

Perioperative morbidity and outcome of esophageal surgery in dogs and cats: 72 cases (1993–2013)

OBJECTIVE To evaluate perioperative morbidity and outcome in dogs and cats undergoing esophageal surgery. DESIGN Retrospective case series. ANIMALS 63 client-owned dogs and 9 client-owned cats. PROCEDURES Medical records of dogs and cats that underwent esophageal surgery were reviewed for information on signalment, history, results of preoperative diagnostic testing, condition treated, details of surgery, intraoperative complications, and postoperative complications. Long-term follow-up data were obtained via veterinarian and client telephone conversations. The relationship between complications and survival to hospital discharge was evaluated by means of regression analysis. RESULTS The most common indication for surgical intervention was an esophageal foreign body in dogs (50/63 [79%]) and esophageal stricture in cats (3/9). Complications were documented in 54% (34/63) of dogs and 3 of 9 cats. The most common immediate postoperative complications were respiratory in nature (9 dogs, 1 cat). Partial esophagectomy and resection with anastomosis were significantly associated with the development of immediate postoperative complications in dogs. The most common delayed postoperative complications were persistent regurgitation (7 dogs) and esophageal stricture formation (3 dogs, 1 cat). For dogs, a mass lesion and increasing lesion size were significantly associated with the development of delayed postoperative complications. Six dogs (10%) and 1 cat died or were euthanized prior to discharge, and pneumomediastinum and leukopenia were negative prognostic factors for dogs being discharged from the hospital. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study suggested that the short-term prognosis for dogs and cats that survive surgery for treatment of esophageal lesions is favorable, with 90% of patients discharged from the hospital (57/63 dogs; 8/9 cats). However, dogs treated for more extensive esophageal lesions as well as those undergoing esophagectomy or resection and anastomosis were more likely to develop postoperative complications.

Effect of laser treatment on first-intention incisional wound healing in ball pythons (Python regius).

OBJECTIVE To evaluate effects of laser treatment on incisional wound healing in ball pythons (Python regius). ANIMALS 6 healthy adult ball pythons. PROCEDURES Snakes were sedated, a skin biopsy specimen was collected for histologic examination, and eight 2-cm skin incisions were made in each snake; each incision was closed with staples (day 0). Gross evaluation of all incision sites was performed daily for 30 days, and a wound score was assigned. Four incisions of each snake were treated (5 J/cm(2) and a wavelength of 980 nm on a continuous wave sequence) by use of a class 4 laser once daily for 7 consecutive days; the other 4 incisions were not treated. Two excisional skin biopsy specimens (1 control and 1 treatment) were collected from each snake on days 2, 7, 14, and 30 and evaluated microscopically. Scores were assigned for total inflammation, degree of fibrosis, and collagen maturity. Generalized linear models were used to investigate the effect of treatment on each variable. RESULTS Wound scores for laser-treated incisions were significantly better than scores for control incisions on day 2 but not at other time points. There were no significant differences in necrosis, fibroplasia, inflammation, granuloma formation, or bacterial contamination between control and treatment groups. Collagen maturity was significantly better for the laser-treated incisions on day 14. CONCLUSIONS AND CLINICAL RELEVANCE Laser treatment resulted in a significant increase in collagen maturity at day 14 but did not otherwise significantly improve healing of skin incisions.

PROSPECTIVE COMPARISON OF TUMOR STAGING USING COMPUTED TOMOGRAPHY VERSUS MAGNETIC RESONANCE IMAGING FINDINGS IN DOGS WITH NASAL NEOPLASIA: A PILOT STUDY

Identification of nasal neoplasia extension and tumor staging in dogs is most commonly performed using computed tomography (CT), however magnetic resonance imaging (MRI) is routinely used in human medicine. A prospective pilot study enrolling six dogs with nasal neoplasia was performed with CT and MRI studies acquired under the same anesthetic episode. Interobserver comparison and comparison between the two imaging modalities with regard to bidimensional measurements of the nasal tumors, tumor staging using historical schemes, and assignment of an ordinal scale of tumor margin clarity at the tumor-soft tissue interface were performed. The hypotheses included that MRI would have greater tumor measurements, result in higher tumor staging, and more clearly define the tumor soft tissue interface when compared to CT. Evaluation of bone involvement of the nasal cavity and head showed a high level of agreement between CT and MRI. Estimation of tumor volume using bidimensional measurements was higher on MRI imaging in 5/6 dogs, and resulted in a median tumor volume which was 18.4% higher than CT imaging. Disagreement between CT and MRI was noted with meningeal enhancement, in which two dogs were positive for meningeal enhancement on MRI and negative on CT. One of six dogs had a higher tumor stage on MRI compared to CT, while the remaining five agreed. Magnetic resonance imaging resulted in larger bidimensional measurements and tumor volume estimates, along with a higher likelihood of identifying meningeal enhancement when compared to CT imaging. Magnetic resonance imaging may provide integral information for tumor staging, prognosis, and treatment planning.

Lung lobe torsion in seven juvenile dogs

CASE DESCRIPTION 7 juvenile (< 12 months old) dogs with lung lobe torsion were evaluated. CLINICAL FINDINGS All patients were male; breeds included Pug (n = 5), Chinese Shar-Pei (1), and Bullmastiff (1). Dyspnea and lethargy were the most common initial complaints, with a duration of clinical signs ranging from 1 to 10 days. A CBC showed leukocytosis and neutrophilia in all dogs. Anemia was present in 6 dogs, 2 of which received packed RBC transfusions. The diagnosis was made on the basis of results of thoracic radiography, CT, ultrasonography, or a combination of modalities. The left cranial lung lobe was most commonly affected (n = 4), followed by the right middle lung lobe (2) and the right cranial lung lobe (1). TREATMENT AND OUTCOME A lateral intercostal thoracotomy with lobectomy of the affected lobe was performed in all patients. All dogs survived to be discharged between 1 and 2 days postoperatively. Six of 7 owners contacted for follow-up information 7 to 170 months after discharge reported satisfaction with the treatment and no apparent signs of recurrence of disease. CLINICAL RELEVANCE The juvenile patients of this report were successfully treated surgically with no apparent complications. Clinicians should be aware of the possibility of lung lobe torsion when evaluating young dogs with clinical signs related to the respiratory system, including those with vague signs, to avoid undue delays in treatment.

GADOXETATE DISODIUM (GD‐EOB‐DTPA) CONTRAST ENHANCED MAGNETIC RESONANCE IMAGING CHARACTERISTICS OF HEPATOCELLULAR CARCINOMA IN DOGS

Hepatocellular carcinoma is the most common primary hepatic tumor in dogs and is amenable to surgical resection in many cases. Unfortunately, overlap of sonographic findings between benign and malignant hepatic lesions typically requires more invasive diagnostic tests to be performed (e.g., biopsy for histopathology). The availability of a noninvasive diagnostic test to identify hepatocellular carcinoma would be beneficial. The use of a liver-specific magnetic resonance imaging (MRI) contrast agent such as gadoxetate disodium (Gd-EOB-DTPA; Eovist® or Primovist®) has improved lesion detection in human patients. In this descriptive study, gadoxetate disodium contrast-enhanced MRI characteristics in dogs were evaluated in seven dogs (total of eight lesions). The imaging characteristics were variable with the exception of all lesions being hypointense to surrounding normal hepatic parenchyma on 3D T1-weighted gradient recalled echo images at all postcontrast time points. All lesions displayed signal intensity ratios less than 1, consistent with retained but impaired hepatocyte function. Hepatic lesions not identified on previous imaging were found in 3/7 patients which may affect surgical planning. In two patients, several hepatic nodules were identified during surgery which had not been visualized on MRI and were found to be benign on histopathology. This descriptive study reports the MRI characteristics of hepatocellular carcinoma in dogs using the liver-specific contrast agent gadoxetate disodium.

Bariatric Radioembolization: A Pilot Study on Technical Feasibility and Safety in a Porcine Model

PURPOSE To evaluate feasibility of left gastric artery (LGA) yttrium-90 ((90)Y) radioembolization as potential treatment for obesity in a porcine model. MATERIALS AND METHODS This study included 8 young female pigs (12-13 weeks, 21.8-28.1 kg). Six animals received infusions of (90)Y resin microspheres (46.3-105.1 MBq) into the main LGA and the gastric artery arising from the splenic artery. Animal weight and serum ghrelin were measured before treatment and weekly thereafter. Animals were euthanized 69-74 days after treatment, and histologic analyses of mucosal integrity and ghrelin immunoreactive cell density were performed. RESULTS Superficial mucosal ulcerations < 3.0 cm(2) were noted in 5 of 6 treated animals. Ghrelin immunoreactive cell density was significantly lower in treated versus untreated animals in the stomach fundus (13.5 vs 34.8, P < .05) and stomach body (11.2 vs 19.8, P < .05). Treated animals gained less weight than untreated animals over the study duration (40.2 kg ± 5.4 vs 54.7 kg ± 6.5, P = .053). Average fundic parietal area (165 cm(2) vs 282 cm(2), P = .067) and average stomach weight (297.2 g vs 397.0 g, P = .067) were decreased in treated versus untreated animals. Trichrome staining revealed significantly more fibrosis in treatment animals compared with control animals (13.0 vs 8.6, P < .05). No significant differences were identified in plasma ghrelin concentrations (P = .24). CONCLUSIONS LGA (90)Y radioembolization is promising as a potential treatment for obesity. A larger preclinical study is needed to evaluate the safety and efficacy of this procedure further.

Effects of hyperbaric oxygen therapy on uncomplicated incisional and open wound healing in dogs

OBJECTIVE To determine the safety of a hyperbaric oxygen therapy (HBOT) protocol and its influence on the healing of uncomplicated open and incisional wounds in dogs. STUDY DESIGN Prospective, controlled experimental study. ANIMALS Adult dogs (n = 10). METHODS Two 2 × 2-cm open wounds and two 3-cm-long full-thickness dermal incisions were created on the dorsum of each dog. Dogs in the hyperbaric oxygen treatment group (HBO) received HBOT once daily (1.7 atmospheres absolute [ATA], 30 minutes on day 1; 2.0 ATA, 40 minutes on days 2-7) for 7 consecutive days, and dogs in the control group (CON) received standardized wound care. Dogs were monitored during HBOT for adverse side effects. Total wound area, percentage epithelialization, and percentage contraction were compared for the open wounds. Subjective wound scores were compared for the open and incisional wounds. Biopsies of both wound types were taken and used to determine histopathology scores. Bacterial cultures were completed on open wounds. RESULTS No difference was detected between HBO and CON uncomplicated open and incisional wounds at any time for contraction, epithelialization, subjective wound scores, histopathology scores, or bacterial loads. All HBO dogs tolerated hyperbaric oxygen treatments with no adverse effects. CONCLUSION The HBOT protocol tested here was safe but did not enhance the healing of uncomplicated acute wounds and incisions of dogs. CLINICAL SIGNIFICANCE These results do not provide evidence to support the use of HBOT to manage uncomplicated wounds in dogs.