Gyrodactylid ectoparasites in a population of rainbow trout (Oncorhynchus mykiss).

A colony of rainbow trout (Oncorhynchus mykiss) in a decentralized aquatic animal facility was noted to have an increase in morbidity and mortality (from 4 or 5 fish each month to 3 or 4 fish daily) approximately 2 wk after experimental procedures began. The primary clinical signs were erratic swimming behavior and 'flashing' of fish against surfaces within housing enclosures. Moribund and normal rainbow trout were presented alive for diagnostic evaluation; samples of water from housing enclosures were provided for water quality assessment. The trout were determined to be infected with gyrodactylids, a common monogenean ectoparasite of the skin and gills in both marine and freshwater fish. This case report describes the diagnosis, pathology, and treatment of gyrodactylids and husbandry modifications associated with the resolution of this clinical aquatic-animal case.

Clean technique for prolonged nonsurvival cardiothoracic surgery in swine (Sus scrofa).

Laboratory animal regulations provide little guidance regarding duration of nonsurvival surgery requiring aseptic technique. We hypothesized that swine would experience no sepsis during nonsurvival cardiothoracic surgery accomplished by using clean technique and lasting 8 h or less. Incision sites of 5 male farm pigs (Sus scrofa) were shaved and then cleaned with alcohol and povidone-iodine. The surgeon wore sterile gloves, clean scrubs, and hair bonnet; assistants wore clean scrubs and nonsterile gloves; most instruments were autoclaved. A median sternotomy incision was used for thoracic cavity exposure, and the skull was exposed to allow induction of brain death. Heart rate, body temperature, and blood samples were obtained before surgery (0 h; baseline) and at 2, 4, 5 or 6, and 7 or 8 h thereafter. Statistical analysis by t-tests showed that heart rate was unchanged and body temperature increased after the 0-h (baseline) time point. Aerobic blood cultures were negative except for 2 samples that were positive for coagulase-negative Staphylococcus spp. at 4 h. RBC, Hgb, and Hct levels were decreased at 2 and 4 h, but WBC and platelets were unchanged. Other alterations included decreased glucose (at 7 or 8 h), increased BUN (at 5 or 6 h and 7 or 8 h) and creatinine (at 5 or 6 h), decreased Na(+) and Ca and increased K(+) (most time points), decreased total protein and albumin (most time points), and decreased globulin (at 7 or 8 h). Liver enzymes and bilirubin typically were unchanged, and cholesterol consistently was decreased. Together our results indicate a lack of sepsis for 8 h or less in pigs undergoing cardiothoracic surgery by using clean technique. These findings provide new and specific data regarding the use of aseptic technique during prolonged nonsurvival surgeries.

Hematopoietic protein-1 regulates the actin membrane skeleton and membrane stability in murine erythrocytes.

Hematopoietic protein-1 (Hem-1) is a hematopoietic cell specific member of the WAVE (Wiskott-Aldrich syndrome verprolin-homologous protein) complex, which regulates filamentous actin (F-actin) polymerization in many cell types including immune cells. However, the roles of Hem-1 and the WAVE complex in erythrocyte biology are not known. In this study, we utilized mice lacking Hem-1 expression due to a non-coding point mutation in the Hem1 gene to show that absence of Hem-1 results in microcytic, hypochromic anemia characterized by abnormally shaped erythrocytes with aberrant F-actin foci and decreased lifespan. We find that Hem-1 and members of the associated WAVE complex are normally expressed in wildtype erythrocyte progenitors and mature erythrocytes. Using mass spectrometry and global proteomics, Coomassie staining, and immunoblotting, we find that the absence of Hem-1 results in decreased representation of essential erythrocyte membrane skeletal proteins including α- and ß- spectrin, dematin, p55, adducin, ankyrin, tropomodulin 1, band 3, and band 4.1. Hem1⁻/⁻ erythrocytes exhibit increased protein kinase C-dependent phosphorylation of adducin at Ser724, which targets adducin family members for dissociation from spectrin and actin, and subsequent proteolysis. Increased adducin Ser724 phosphorylation in Hem1⁻/⁻ erythrocytes correlates with decreased protein expression of the regulatory subunit of protein phosphatase 2A (PP2A), which is required for PP2A-dependent dephosphorylation of PKC targets. These results reveal a novel, critical role for Hem-1 in the homeostasis of structural proteins required for formation and stability of the actin membrane skeleton in erythrocytes.

Hem-1: putting the "WAVE" into actin polymerization during an immune response.

Most active processes by immune cells including adhesion, migration, and phagocytosis require the coordinated polymerization and depolymerization of filamentous actin (F-actin), which is an essential component of the actin cytoskeleton. This review focuses on a newly characterized hematopoietic cell-specific actin regulatory protein called hematopoietic protein-1 [Hem-1, also known as Nck-associated protein 1-like (Nckap1l or Nap1l)]. Hem-1 is a component of the "WAVE [WASP (Wiskott-Aldrich syndrome protein)-family verprolin homologous protein]" complex, which signals downstream of activated Rac to stimulate F-actin polymerization in response to immuno-receptor signaling. Genetic studies in cell lines and in mice suggest that Hem-1 regulates F-actin polymerization in hematopoietic cells, and may be essential for most active processes dependent on reorganization of the actin cytoskeleton in immune cells.