Often referred to as the silent killer, ovarian cancer is the most lethal gynecologic malignancy. This disease rarely shows any physical symptoms until late stages and no known biomarkers are available for early detection. Because ovarian cancer is rarely detected early, the physiology behind the initiation, progression, treatment, and prevention of this disease remains largely unclear. Over the past 2 decades, the laying hen has emerged as a model that naturally develops epithelial ovarian cancer that is both pathologically and histologically similar to that of the human form of the disease. Different molecular signatures found in human ovarian cancer have also been identified in chicken ovarian cancer including increased CA125 and elevated E-cadherin expression, among others. Chemoprevention studies conducted in this model have shown that decreased ovulation and inflammation are associated with decreased incidence of ovarian cancer development. The purpose of this article is to review the major studies performed in laying hen model of ovarian cancer and discuss how these studies shape our current understanding of the pathophysiology, prevention, and treatment of epithelial ovarian cancer.

Slc1a5 (ASCT2) encodes a small neutral amino-acid exchanger and is the most well-studied glutamine transporter in cancer cells. To investigate the role of Slc1a5 in osteoclastogenesis, we developed Slc1a5-deficient mice by using a conventional gene-targeting approach. The Slc1a5^–/– mice showed no obvious abnormalities in growth. Glutamine uptake was assessed in Slc1a5^+/+ and Slc1a5^–/– bone marrow cells stimulated with RANKL. The rate of glutamine uptake in Slc1a5^–/– bone marrow cells was reduced to 70% of that of cells from Slc1a5^+/+ bone marrow. To confirm the involvement of Slc1a5 in osteoclast formation, bone marrow cells derived from Slc1a5^+/+ or Slc1a5^–/– mice were stimulated with RANKL and macrophage colony-stimulating factor and stained with tartrate-resistant acid phosphatase. The bone resorption activity and actin ring formation of stimulated cells were measured. The formation of multinucleated osteoclasts in bone marrow cells isolated from Slc1a5^–/– mice was severely impaired compared with those from Slc1a5^+/+ mice. RANKL-induced expression of ERK, NFκB, p70S6K, and NFATc1 was suppressed in Slc1a5^–/– osteoclasts. These results show that Slc1a5 plays an important role in osteoclast formation.

The intestinal microbiota of an organism can significantly alter outcome data in otherwise identical experiments. Occasionally, animals may require sedation or anesthesia for scientific or health-related purposes, and certain anesthetics, such as ketamine, can profoundly affect the gastrointestinal system. While many factors can alter the gut microbiome (GM), the effects of anesthetics on the composition or diversity of the GM have not been established. The goal of the current study was to determine whether daily administration of ketamine would significantly alter the microbiome of CD1 mice. To achieve this goal, female CD1 mice received daily injections of ketamine HCl (100 mg/kg) or the equivalent volume of 0.9% saline for 10 consecutive days. Fecal samples were collected before the first administration and 24 h after the final dose of either ketamine or saline. Samples were analyzed by 16S rRNA sequencing to identify changes between groups in diversity or composition of GM. The study found no significant changes to the GM after serial ketamine administration when treated mice were housed with controls. Therefore, ketamine administration is unlikely to alter the GM of a CD1 mouse and should not serve be a confounding factor in reproducibility of research.

Aging is associated with a progressive decline in physical function characterized by decreased mobility, which is an important risk factor for loss of independence and reduced quality of life. Functional testing conducted in animals has advanced our understanding of age-related changes in physical ability and contributed to the development of physiologic measurements that can be used to assess functional changes during aging. The balance beam test is one assessment tool used to measure age-related changes in balance and coordination. The goal of this study is to provide analytical examples and psychometric support of a protocol that has been analyzed to show how the number of successive test runs, foot slips, pauses, and hesitations affect the reliability of the primary outcome measure, which is the time to cross the beam. Our results suggest that conducting more than 1 training session, consisting of greater than or equal to 3 successful training runs, followed by at least one test session with no less than 2 successful runs (that is, runs without pauses or hesitations) provides a psychometrically sound outcome. The data presented here indicate that a psychometric approach can improve protocol design and reliability of balance beam measures in mice.

Melatonin, the circadian nighttime neurohormone, and eicosapentaenoic acid (EPA) and docosahexaenoic acids (DHA), which are omega-3 fatty acids (FA) found in high concentrations in fish oil (FO) and plants, abrogate the oncogenic effects of linoleic acid (LA), an omega-6 FA, on the growth of rodent tumors and human breast, prostate, and head and neck squamous cell carcinoma (HNSCC) xenografts in vivo. Here we determined and compared the long-term effects of these inhibitory agents on tumor regression and LA uptake and metabolism to the mitogenic agent 13-[S]-hydroxyoctadecadienoic acid (13-[S]-HODE) in human prostate cancer 3 (PC3) and FaDu HNSCC xenografts in tumor-bearing male nude rats. Rats in this study were split into 3 groups and fed one of 2 diets: one diet containing 5% corn oil (CO, high LA), 5% CO oil and melatonin (2 μg/mL) or an alternative diet 5% FO (low LA). Rats whose diet contained melatonin had a faster rate of regression of PC3 prostate cancer xenografts than those receiving the FO diet, while both in the melatonin and FO groups induced the same rate of regression of HNSCC xenografts. The results also demonstrated that dietary intake of melatonin or FO significantly inhibited tumor LA uptake, cAMP content, 13-[S]-HODE formation, [³H]-thymidine incorporation into tumor DNA, and tumor DNA content. Therefore, long-term ingestion of either melatonin or FO can induce regression of PC3 prostate and HNSCC xenografts via a mechanism involving the suppression of LA uptake and metabolism by the tumor cells.

A small colony of zebrafish (Danio rerio) experienced 30% acute mortality within a few days after receipt from a commercial source. A few fish presented with small areas of raised scales or tissue necrosis, primarily near the caudal peduncle. Edwardsiella ictaluri (E. ictaluri) was identified by real-time PCR of pooled zebrafish and swabs of the pre-filter and fine filter pads, with subsequent sequence analysis. E. ictaluri is most commonly associated with an enteric septicemia in catfish species and can have significant economic impact on commercial catfish fisheries. However, several references report naturally occurring E. ictaluri infection of nonictalurid fishes, including zebrafish. Ours is the first report demonstrating the use of environmental sampling to identify E. ictaluri in a zebrafish colony by real-time PCR. Moreover, our report indicates that E. ictaluri is a relevant disease for institutions using zebrafish as research species and emphasizes the importance of carefully considering importation and quarantine practices.