Clinical and pharmacokinetic characteristics of intracavitary administration of pegylated liposomal encapsulated doxorubicin in dogs with splenic hemangiosarcoma

BACKGROUND: Canine splenic hemangiosarcoma (HSA) is a fatal malignancy, and most affected dogs die within a few months of diagnosis. Most dogs present with signs from tumor rupture, resulting in hemoabdomen and intra-abdominal dissemination. The abdomen is also the main site of disease recurrence. HYPOTHESIS: Intraperitoneal (IP) administration of doxorubicin will delay or prevent intra-abdominal tumor recurrence and prolong survival in dogs with HSA. ANIMALS: Fourteen dogs with splenic HSA. METHODS: A prospective, unmasked, uncontrolled clinical trial. After staging of disease status and splenectomy, pegylated liposomal encapsulated doxorubicin was administered intraperitoneally (1 mg/kg body weight) every 3 weeks for 4 cycles. All dogs were monitored for recurrence of HSA. Samples of plasma and abdominal fluid were collected for measurement of doxorubicin concentration and pharmacokinetic analysis. Nonlinear mixed-effect modeling was used to describe the pharmacokinetics of liposomal doxorubicin administered IP. RESULTS: All 14 dogs died, 12 because of HSA and 2 from other causes. Postmortem examination was performed on 12 dogs. All 12 dogs died because of HSA-related causes and had hepatic metastases and hemoabdomen. The IP-treated dogs had fewer serosal, mesenteric, and omental metastases than historical controls treated with systemic doxorubicin. Results of the postmortem examination and pharmacokinetic analysis confirmed that IP delivery of doxorubicin resulted in an effective drug concentration with a clearance comparable with that after i.v. delivery. CONCLUSIONS AND CLINICAL IMPORTANCE: IP pegylated liposomal encapsulated doxorubicin administration did not prevent intraabdominal recurrence of HSA in dogs.     

Alkalinity and Hardness: Critical but Elusive Concepts in Aquaculture

Total alkalinity and total hardness are familiar variables in aquatic animal production. Aquaculturists—both scientists and practitioners alike—have some understanding of the two variables and of methods for adjusting their concentrations. The chemistry and the biological effects of alkalinity and hardness, however, are more complex than generally realized or depicted in the aquaculture literature. Moreover, the discussions of alkalinity and hardness—alkalinity in particular—found in water chemistry texts are presented in a rigorous manner and without explanation of how the two variables relate to aquaculture. This review provides a thorough but less rigorous discussion of alkalinity and hardness specifically oriented toward aquaculture. Alkalinity and hardness are defined, their sources identified, and analytical methods explained. This is followed by a discussion of the roles of the two variables in aquaculture, including their relationships with carbon dioxide, pH, atmospheric pollution, ammonia, and other inorganic nitrogen compounds, phytoplankton communities, trace metals, animal physiology, and clay turbidity. Liming and other practices to manage alkalinity and hardness are explained. Changes in alkalinity and hardness concentrations that occur over time in aquaculture systems are discussed. Emphasis is placed on interactions among alkalinity, hardness, water quality, and aquacultural production.     

Some Limiting Factors in Superintensive Production of Juvenile Pacific White Shrimp,Litopenaeus vannamei,in No‐water‐exchange,Biofloc‐dominated Systems

Superintensive shrimp culture in zero‐exchange, biofloc‐dominated production systems is more biosecure and sustainable than traditional shrimp farming practices. However, successful application of this technology depends upon optimizing dietary formulations, controlling Vibrio outbreaks, and managing accumulative changes in water quality and composition. A 49‐d study investigated the effect of two commercial feeds of differing protein content and an indoor limited‐exchange, biofloc‐dominated culture environment on Litopenaeus vannamei performance and tissue composition, water quality and ionic composition, and Vibrio dynamics. Juveniles (5.3 g) were stocked at 457/m³ into four 40 m³ shallow raceways containing biofloc‐dominated water and fed one of two commercial feeds with differing protein content, 35 or 40%. Shrimp performance, Vibrio populations, and changes in shrimp and culture water composition were monitored. There were no significant differences (P > 0.05) in shrimp performance (survival, weight, growth, specific growth rate, total biomass, yield, feed conversion ratio, and protein efficiency ratio) or proximate composition between feed types. The 40% protein feed resulted in higher culture water nitrate and phosphate concentrations, alkalinity consumption and bicarbonate use, and higher phytoplankton density. The presence of Vibrio, specifically Vibrio parahaemolyticus, reduced shrimp survival. This survival decrease corresponded with increased culture water Vibrio concentrations. Culture water K⁺ and Mg²⁺ increased significantly (P < 0.05), and Sr²⁺, Br^?, and Cl^? decreased significantly (P < 0.05) over time. While Cu²⁺ and Zn²⁺ did increase in shrimp tissue, no heavy metals accumulated to problematic levels in culture water or shrimp tissue. These results demonstrate the importance of monitoring Vibrio populations and ionic composition in limited‐exchange shrimp culture systems.     

Uptake and metabolism as mechanisms of selective herbicidal activity of the 1,2,4-triazolo[1,5-a] pyrimidines

In order to identify the factors providing the triazolopyrimidines with a wide range of selectivity amongst agriculturally important plant species, studies were made on the uptake and metabolism of a representative compound, N-(2,6-dichlorophenyl)-5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine- 2-sulfonamide. This compound is much more phytotoxic to dicots than to monocots. Experiments showed that variations in leaf morphologies and geometries relative to spray applications resulted in different herbicide dosages applied to plant species used in selectivity evaluations. However, this parameter did not have a statistically significant correlation to herbicide selectivity measurements. Characterization of the metabolic pathways showed that the major herbicide metabolites involved methyl hydroxylation or hydroxylation of the aniline ring followed by glucose conjugation. Since these metabolites were not exclusive to either monocots or dicots, herbicide selectivity does not appear dependent on the pathway of metabolism. Studies on the kinetics of metabolism suggest instead that metabolic rate was important. Monocots metabolized the herbicide rapidly and generally were tolerant while the opposite was true of dicots.     

Correlation between leukocytosis and necropsy findings in dogs with immune-mediated hemolytic anemia: 34 cases (1994-1999)

OBJECTIVE: To determine whether severity of leukocytosis correlates with severity of postmortem lesions in dogs with immune-mediated hemolytic anemia (IMHA). DESIGN: Retrospective study. ANIMALS: 34 dogs with IMHA that had CBC performed within 48 hours prior to death and complete necropsy examinations. PROCEDURE: Dogs were independently assigned to 4 leukocytosis groups (within reference range; mild leukocytosis, moderate leukocytosis, marked leukocytosis) and 3 lesion severity groups (mild lesions, moderate lesions, severe lesions). RESULTS: Moderate to marked leukocytosis correlated with moderate to severe postmortem lesions. Ischemic necrosis within liver, kidney, heart, lung, and spleen attributable to thromboembolic disease or anemic hypoxia were the most common important lesions found at necropsy. None of the dogs with mild lesions had moderate or marked leukocytosis. Four of 14 severely affected dogs had WBC counts within reference range, but all 4 had neutrophilic left shifts. Three of these 4 dogs had toxic change in neutrophils. CONCLUSION AND CLINICAL RELEVANCE: Moderate to marked leukocytosis, neutrophilic left shift, and toxic change in neutrophils in dogs with IMHA should alert clinicians to the potential for moderate to severe tissue injury, which could complicate treatment and worsen prognosis. Lesions appear to be secondary to anemic hypoxia, thromboembolic disease, or both; therefore, treatment objectives should focus on improving blood oxygen-carrying capacity and monitoring for thromboembolic disease.     

Ranch-management factors associated with antibody seropositivity for Neospora caninum in consignments of beef calves in Texas, USA

A study was conducted with a 1998 retained-ownership population of Texas (USA) beef calves to determine the ranch-management practices associated with calf seroprevalence to Neospora caninum. Management practices of 76 Texas ranches that consigned 760 calves to a retained-ownership feedlot program were reviewed from a mailed questionnaire. Ninety-nine of 760 (13%; 95% CI, 9.4%, 17.7%) calves were positive to N. caninum and 59% of the ranches consigned at least one positive calf. In the logistic multiple-regression model which controlled for overdispersion, increased odds of calf-level seropositivity was associated with seasonal calving patterns, with stocking>1cow/calfunit/2.2ha, using a round-bale feeder, allowing wildlife access to the weaning supplement, and self-reared replacement heifers. However, decreased odds of seropositivity was associated with using a cattle-working dog and with using a self-contained cattle feeder. There was substantial overdispersion due to ranch.     

Diagnostic imaging of lameness in small animals.

The demand for advanced diagnostic imaging procedures such as nuclear scintigraphy, ultrasonography, computed tomography, and magnetic resonance imaging has increased dramatically over the past 10 years. Veterinarians, seeking to improve their diagnostic capabilities and clients willing to pursue "best medicine" have driven this demand, resulting in installation of advanced imaging facilities at most academic and private referral practices. Knowledge of potential benefits of various modalities will allow the veterinarian to optimize his or her use of diagnostic imaging in his or her own practice or in a referral practice.     

Adrenal teratoma in four domestic ferrets (Mustela putorius furo)

Teratomas are histologically complex neoplasms that are composed of structures derived from multiple germ cell layers (ectoderm, mesoderm, and endoderm). These neoplasms are uncommon in domestic animals and are usually found in the gonads. This paper describes teratomas of the adrenal gland in four domestic ferrets (Mustela putorius furo). Three of four of the neoplasms contained tissues from ectodermal, mesodermal, and endodermal germ cell layers; two of four contained rudimentary teeth. In one case, malignant epithelial cells had metastasized to local lymph nodes. Teratomas, although uncommon, should be included in the differential diagnosis for adrenal neoplasms in domestic ferrets.