A blastogenic test for foot-and-mouth disease.

A blastogenic test to detect peripheral blood leukocytes specifically sensitized to foot-and-mouth disease virus antigen is described. The test is carried out in microtitre plates and optimum conditions were found by titration. These employed 7.5 x 10(5) cells/well and 20 complement fixing units of antigen. Peak [3H]thymidine incorporation was found to take place at 2-3 days.     

Immune response to virus-infection-associated (VIA) antigen in cattle repeatedly vaccinated with foot-and-mouth disease virus inactivated by formalin or acetylethyleneimine.

The results of experiments to investigate antibody to 'virus infection associated' (VIA) antigen in cattle repeatedly vaccinated with formalin- or acetylethyleneimine- (AEI) inactivated foot-and-mouth disease (FMD) vaccines under laboratory conditions are reported. Results are also presented from some vaccinated animals subsequently exposed to FMD infection. Antibody against VIA was not detected before and after the first vaccination with formalin or AEI-inactivated vaccine but did develop in all animals after the second formalin vaccination and persisted throughout the experiment. After the second AEI vaccination, 4 of 12 animals developed antibody which persisted for at least 37 days. This transient response in some cattle was repeated after successive vaccinations but, in general, more animals responded as the number of vaccinations increased. After exposure to infection a transient VIA antibody response was occasionally observed in immune AEI-vaccinated animals. Some immune repeatedly AEI-vaccinated cattle did not develop detectable VIA antibody after challenge despite the persistence of virus in oesophageal-pharyngeal (O/P) fluid. The presence of antibody to VIA antigen is not conclusive proof that vaccinated animals have been exposed to infection and field data must be interpreted with caution.     

Relationship of N-arylacetamide metabolism and macromolecular binding to oncogenic transformation of C3H10T1/2CL8 cells

The C3H10T1/2CL8 mouse embryo oncogenic transformation bioassay system detects a wide variety of chemical carcinogens. However, one carcinogen that does not transform C3H10T1/2CL8 cells is the liver carcinogen N-2-fluorenylacetamide (FAA). Previous reports indicate that an activated form of FAA,N-acetoxy-FAA (N-OAc-FAA), transforms these fibroblasts. In an effort to understand these results, the metabolism and binding to cellular macromolecules of FAA and N-OAc-FAA using C3H10T1/2CL8 cells was investigated. C3H10T1/2CL8 cells metabolized FAA to 7-hydroxy-FAA, 2-fluorenylamine and N-hydroxy-FAA (N-OH-FAA) at rates of 5.03, 2.22 and 3.33 pmol/h/10⁶ cells, respectively. N-OAc-FAA was bound to the DNA and RNA in C3H10T1/2CL8 cells to the extent of 10.6 and 3.6 FAA residues/10⁶ nucleotides, respectively, and to protein at 21.9 pmol FAA residues/mg protein. However, binding of FAA to DNA and RNA at similar concentrations to N-OAc-FAA was less than 0.3 and 0.6 residues/10⁶ nucleotides, respectively. These results strongly indicate that the inability of FAA to transform C3H10T1/2CL8 cells resides in the cells' inability to metabolize it sufficiently to the proximate carcinogen N-OH-FAA and not an inherent insensitivity to its activated forms.     

Cell cycle-dependent nucleocytoplasmic shuttling of the neurofibromatosis 2 tumour suppressor merlin

The neurofibromatosis 2 tumour suppressor merlin/schwannomin is structurally related to the ezrin-radixin-moesin family of proteins, which anchor actin cytoskeleton to specific membrane proteins and participate in cell signalling. Merlin inhibits cell growth with a yet unknown mechanism. As most tumour suppressors are linked to cell cycle control, we investigated merlin's behaviour during cell cycle. In glioma and osteosarcoma cells, endogenous merlin was targeted to the nucleus in a cell cycle-specific manner. Merlin accumulated perinuclearly at the G2/M phase, and shifted to the nucleus at early G1. During mitosis, merlin localized to mitotic spindles and at the contractile ring. Nuclear merlin was strongly reduced in confluent cells. Blocking of the CRM1/exportin nuclear export pathway led to accumulation of merlin in the nucleus. Activation of the p21-activated kinase or protein kinase A, which result in phosphorylation of merlin, did not affect its nuclear localization. Merlin regulates the activity of extracellular signal-regulated kinase 2 (ERK2) and nuclear localization of both proteins was induced by cell adhesion. Unlike ERK2, nuclear localization of merlin was not, however, dependent on intact actin cytoskeleton. These results link merlin to events related to cell cycle control and may help to resolve its tumour suppressor function.     

Dendrimer-enhanced MRI as a diagnostic and prognostic biomarker of sepsis-induced acute renal failure in aged mice

BACKGROUND: Acute renal failure (ARF) induced by sepsis has a high mortality. In an aged mouse model of sepsis-induced ARF we have previously shown that renal injury occurs before serum creatinine is elevated. Development of a noninvasive biomarker that could diagnose renal dysfunction early in sepsis and monitor the response to therapy would be very valuable. METHODS: We performed magnetic resonance imaging (MRI) with gadolinium-based G4 dendrimer intravenous contrast in a fluid- and antibiotic-treated cecal ligation and puncture (CLP) sepsis model in aged mice. Imaging was also performed in a mouse volume depletion model and in models of ARF induced by ischemia/reperfusion (I/R) and cisplatin. RESULTS: Twenty hours post-CLP, aged mice had a distinct pattern of renal injury using dendrimer-enhanced MRI. This pattern was different from renal injury induced by either cisplatin or I/R. Prerenal azotemia induced by volume depletion was distinguished from sepsis by dendrimer-enhanced MRI. Dendrimer-enhanced MRI detected renal dysfunction 6 hours post-CLP, a time when serum creatinine was still normal. Ethyl pyruvate reversed the renal dysfunction detected by dendrimer-enhanced MRI at 20 hours, but not at 6 hours post-CLP. The appearance of renal dysfunction on dendrimer-enhanced MRI at 6 hours post-CLP predicted the length of survival. CONCLUSION: Dendrimer-enhanced MRI is a novel biomarker that provides information for the early diagnosis, drug responsiveness, and prognosis of sepsis-induced ARF.     

Fine structure of the corpuscles of stannius of the trout, Salmo gairdneri: Structural changes in response to increased environmental salinity and calcium ions

These studies confirm that there are two cell types, C₁ and C₂, in the corpuscles of Stannius (CS) of the trout, Salmo gairdneri, both of which have the appearance of protein-or peptide-secreting cells. C₁ cells have large secretory granules, up to 1.0 μm in diameter, while the C₂ cells have small granules up to 0.5 μm. In seawater (SW)-adapted trout the C₂ cell granules are significantly larger than those in freshwater (FW)-adapted trout. In fresh water the C₁ cells are relatively inactive and the C₂ cells are mainly sparsely granulated and actively secreting. The converse situation is found in seawater-adapted trout in which the C₁ cells are very active and the C₂ cells are relatively inactive and contain stored granules. During adaptation to SW from FW some C₁ cells develop extensive rough endoplasmic reticulum and Golgi but other C₁ cells degenerate and disintegrate apparently releasing the entire cell contents, including granules, into the capillary lumena. Protein may be released from these granules in capillaries by digestive enzymes from lysosome-like vesicles. In both adapted FW and SW corpuscles the active cells appear to release their granules by exocytosis. The appearance of C₁ cells of fish transferred from FW to calcium-enriched fresh water is similar to that of fish transferred to dilute SW, suggesting that these cells respond to high levels of external calcium, while the C₂ cells are active in media of low ionic and osmotic strength.