A retrospective analysis of stereotactic body radiation therapy for canine heart base tumors: 26 cases.

INTRODUCTION: This study retrospectively evaluated outcomes and adverse radiation effects (AREs) associated with stereotactic body radiation therapy (SBRT) for canine heart base tumors (HBTs). A secondary aim was to identify any demographic or echocardiographic factors that might determine which dogs would most benefit from SBRT. ANIMALS: Twenty-six dogs that received SBRT for an imaging-based diagnosis of a HBT were evaluated. METHODS: Twenty-three dogs were treated with three fractions of 10 Gy delivered daily or every other day. The remaining 3 dogs received variable protocols of one to five fractions. Demographic, echocardiographic, and radiographic information, AREs, and treatment responses were collected. Correlations of these data with survival time were evaluated. RESULTS: The median overall survival time was 404 days (95% confidence interval: 239-554 days). The majority of dogs experienced a partial response (25%) or stable disease (60%) for a median duration of 333 days (95% confidence interval: 94-526 days). Three dogs had progressive disease within six months of SBRT. Radiographic pneumonitis was identified in 7 of 23 dogs, and clinical pneumonitis was identified in 4 dogs. No other AREs were noted. The rate of distant metastasis was 13%. On multivariate analysis, it was found that vena caval obstruction, supraventricular and ventricular arrhythmias, clinical signs, and enlarged locoregional lymph nodes at presentation were negatively associated with survival time. CONCLUSIONS: Stereotactic body radiation therapy was delivered with a low rate and degree of normal tissue complications. Asymptomatic dogs with confirmed, progressive growth of a HBT may most likely benefit from SBRT.

Potential for a novel manganese porphyrin compound as adjuvant canine lymphoma therapy.

PURPOSE: Manganese porphyrins are redox-active drugs and superoxide dismutase mimics, which have been shown to chemosensitize lymphoma, a cancer which frequently occurs in dogs. This study aimed to identify critical information regarding the pharmacokinetics and toxicity of Mn(III) meso-tetrakis (N-n-butoxyetylpyridium-2-yl) porphyrin, (MnTnBuOE-2-PyP5+, MnBuOE) in dogs as a prelude to a clinical trial in canine lymphoma patients. METHODS: A single-dose pharmacokinetic (PK) study in normal dogs was performed to determine the plasma half-life (t 1/2) of MnBuOE. A dose reduction study was performed to establish the maximum tolerated dose (MTD) of MnBuOE. The safety and PK of a multi-dosing protocol was assessed. RESULTS: Peak plasma drug concentration occurred 30 min post-injection. The t 1/2 was defined as 7 h. MnBuOE induced an anaphylactic reaction and prolonged tachycardia. The MTD was defined as 0.25 mg/kg. The dogs were given MTD 3×/week for 2-3 weeks. The highest recorded tissue drug levels were in the lymph nodes (4-6 µM), followed by kidney and liver (2.5, 2.0 uM, respectively). CONCLUSIONS: We obtained critical information regarding the PK and toxicity of MnBuOE in dogs. The acute drug reaction and tachycardia post-injection have not been described in other species and may be specific to canines. The high tissue drug levels in lymph nodes have not been previously reported. MnBuOE accumulation in lymph nodes has important implications for the utility of adjuvant MnBuOE to treat lymphoma. With MnBuOE lymph node accumulation, reduction in the dose and/or administration frequency could be possible, leading to reduced toxicity.

Learning styles of baccalaureate nursing students and attitudes toward theory-based nursing.

The purpose of this study was to investigate personal and environmental factors related to undergraduate and post-RN nursing students' attitudes toward theory-based nursing from Kolb's experimental learning theory perspective. The study is part of a larger project designed to test aspects of Kolb's theory in the nursing population. Hypotheses about relationships among learning styles, perception of environmental press, experience in nursing, attitudes toward theory-based nursing, preferred nursing theory, and preferred method of learning theory were proposed for investigation. Seventy-six post-RN and 121 upper-level generic baccalaureate nursing students each completed two measures of personal learning style, a measure of perception of environmental press of nursing learning environments, and a nursing theories questionnaire. Learning style and environmental press perceptions were found to be significantly related to attitudes toward theory-based nursing. Concrete learners and subjects who perceived nursing environments to be predominantly concrete were significantly less positive toward theory-based nursing than abstract learners. Experience in nursing was found to be related to perception of environmental press. Learning style was not found to be significantly related to preferred method of learning nursing theories nor to preferred nursing theory for practice. Implications for nursing education are discussed.