Platelet - activating factor induces leukotriene C4 synthesis by purified human eosinophils

Platelet-activating factor, at a concentration of 10 μM, was capable of inducing leukotriene C4 synthesis by eosinophils of healthy donors, i.e. (3.1 ± 0.3) × 106 molecules leukotriene C4 /cell (n = 31, mean ± SEM, cell purity 87 ± 2%). Reversed-phase high performance liquid chromatography analysis demonstrated the exclusive synthesis of leukotriene C4. At a concentration of 1 μM, platelet-activating factor was capable of significantly enhancing the calcium ionophore A23187, the opsonized zymosan or the arachidonic acid induced leukotriene C4 synthesis by eosinophils. These results show that PAF is capable of inducing and enhancing the leukotriene C4 formation by human eosinophils

Breathing patterns of awake rats exposed to acrolein and perfluorisobutylene determined with an integrated system of nose-only exposure and online analyzed multiple monitoring of breathing

Studies on changes in breathing patterns of rats due to exposure to acrolein and the Leflon pyrolysis product perfluorisobutylene (PFIB) were performed to evaluate a new developed integrated system of nose- only exposure and multiple monitoring of breathing of up to eight rats. Measurements of breathing was based on nose flow pneumotachography using differential pressure transducers and monitoring on the videoscreen the 12-s breathing records of 4 rats, including online analysis of respiration frequency (f) and respiratory minute volume (V̇(t) simultaneously. Acrolein concentrations (7- 54 ppm) caused an immediate change of the breathing pattern in exposed rats characterized by a concentration-dependent decrease of f and a similar change of V̇(t). Analysis of the breathing records showed increasing postinspiratory apneic periods as major cause of the decreased f. An RD50 of 4.6 ppm for acrolein was calculated (95% confidence limits 2.4 and 7.2 ppm). Acute nose-only exposure of rats to 100 ppm PFIB during 6-18 min did not change the breathing pattern immediately. However, 24 h after exposure a changed breathing pattern was monitored, characterized by small preinspiratory apneic pauses, lung edema was confirmed at histopathological examination. Continued monitoring of breathing patterns after the acute exposure of PFIB showed normal breathing patterns in recovering rats

Guitar recital

Luys MilanJ.S. BachNapoleon CosteFrancisco TarregaIsaac AlbenizAntonio VivaldiDigital audio of these performances is not yet available. You may submit a request for these recordings to be digitized and made available at this site within 10 work days at http://lib.asu.edu/music/services/perfdigitizeform?identifier=1989/4-26C&title=Guitar+recita

An immunochemical assay to detect DNA damage in bovine sperm

An immunochemical assay has been developed to detect oxidative damage in bovine sperm DNA. Sperm DNA contains a large amount of oxidative damage as a result of exposure to exogenous agents, but damage also can caused by normal metabolic processes and the absence of DNA repair in the later stages of spermatogenesis. A freeze-thaw procedure performed on extended bovine sperm in straws did not induce additional DNA damage immediately after thawing compared with nonfrozen extended sperm. The data suggest that the amount of oxidative damage correlated to the percentage of artificially inseminated cows returning to service within 56 days postinsemination, because a number of sires with high sperm concentrations had a large variation in fertility after artificial insemination. These observations have led to the conclusion that by measuring DNA damage in thawed sperm, one might predict the fertility of bulls with high semen concentration

Pathogenesis of skin lesions in mice with chronic proliferative dermatitis (cpdm/cpdm)

Chronic proliferative dermatitis is a spontaneous mutation in C57BL/Ka mice (cpdm/cpdm), showing alopecia, epithelial hyperproliferation, infiltration by eosinophils and macrophages, and vascular dilatation. To further elucidate its pathogenesis, organs of 1-, 2-, 3-, 4-, 5-, and 6-week-old cpdm/cpdm mice were examined. At 4 weeks, the epidermal thickness was increased, whereas already at 3 weeks, the bromodeoxyuridine incorporation was increased in the basal keratinocytes. However, already at the age of 1 week, skin, lungs, and lymph nodes were infiltrated by eosinophils although no macroscopic lesions were present. Compared with control animals, 6-week-old cpdm/cpdm mice had decreased serum IgE levels and increased numbers of mast cells. From the age of 1 week these mast cells became increasingly IgE positive. In contrast, the mast cells of the control animals remained IgE negative. Mast cells of control and cpdm/cpdm mice were interleukin-4 and tumor necrosis factor-alpha positive. A likely explanation for the tissue infiltration of eosinophils could be the release of interleukin-4 and tumor necrosis factor-alpha from activated mast cells. Tumor necrosis factor-alpha may lead to the expression of E- selectin on endothelial cells, facilitating interleukin-4-mediated eosinophil transendothelial migration. Although various pathogenetic aspects of the cpdm/cpdm mouse need further elucidation, this model can be a tool to study eosinophil infiltration, leukocyte-endothelial cell interactions, and mast cell proliferation. Furthermore, the cpdm/cpdm mouse can be used to study chronic inflammatory skin disease because of the severe epidermal proliferation