Development of Cu(II)/Cu(I)-induced quantum dot-mediated fluorescence immunoassay for the sensitive determination of ethyl carbamate.

A series of haptens were rationally designed for producing monoclonal antibodies specific for EC and a simple fluorescence immunoassay platform was developed for the sensitive determination of EC based on alkaline phosphatase (ALP)-triggered Cu+ quenching of CdSe quantum dots (QDs). It was noted that Cd as a fluorescence substrate in CdSe QDs can be selectively substituted by Cu+ that resulted in a more significant fluorescence quenching in comparison with Cu2+. Meanwhile, because ALP catalyzed ascorbic acid phosphate and then assisted the transformation of Cu2+ to Cu+, the change in fluorescence intensity was found to be proportional to ALP concentration. After simple magnetic separation, the sensitivity and linear range of the established assay were improved approximately 53-fold and an order of magnitude, respectively, when compared with the conventional ELISA. The proposed platform was able to both amplify the signal and eliminate matrix interferences, making it a promising to determine EC as well as other contaminants in complex food matrix in a highly sensitive and simple manner. Graphical abstract.

Tabaquismo: alteraciones producidas por el uretano en los receptores de macrófagos y el sistema del complemento / Smoking: alterations by urethano in macrophages, complement system

Se comunican los resultados de un análisis de la acción del uretano sobre las células inmunocompetentes (macrófagos), el sistema del complemento y también en los enterocitos. El estudio de los receptores de macrófagos por medio de la formación de rosetas puso de manifiesto que concentraciones altas de uretano destruyen a los macrófagos y disminuyen la unión con IgG y el tercer componente del complemento. Los resultados obtenidos experimentalmente in vitro sugieren que de acuerdo con el grado y tiempo de la exposición al humo de tabaco se puede romper el equilibrio del sistema inmunitario y de otras poblaciones celulares que desembocan en los procesos patológicos que se relacionan con tabaquismo

Inflammatory cell populations in the airways and parenchyma after antigen challenge in the rat.

We examined the effects of sensitization and antigen challenge on the cellular populations retrieved from the large airways (LA) (generations zero to 5 approximately) and small airways and parenchyma (S/P) of the rat. Male Brown-Norway rats, 7 to 8 wk of age, were either actively sensitized to ovalbumin (n = 24) or sham-sensitized to saline (n = 9), and, 14 days later, they were anesthetized with urethane, intubated endotracheally, and challenged. Aerosols of ovalbumin (5% wt/vol in saline for 5 min) or saline were administered to 12 and six rats, respectively, and measurements of pulmonary resistance (RL) were made for 8 h. The early airway response (ER) was calculated as the highest value of RL in the first hour after challenge, and the late response (LR) was calculated as an increase in RL to greater than 200% of the baseline value in the 4- to 8-h period after challenge. Rats were killed by exsanguination, LA were separated from S/P, and cells were isolated after tissue mincing and digestion with collagenase. Total and differential cell counts and lymphocyte subsets were determined. Antigen challenge significantly increased the cellular yield (mostly neutrophils) from the LA and S/P. Animals with a LR had a lower total cellular yield from the LA and S/P than did animals without a LR. The animals with a LR also had a lower yield of eosinophils and lymphocytes from the S/P than did animals challenged with saline alone. Cellular yields were not lower in the animals with an isolated ER after antigen challenge.(ABSTRACT TRUNCATED AT 250 WORDS)

Catecholamine content of serum and adrenals in protracted anaphylactic shock of guinea pigs.

In ovalbumin-sensitized guinea pigs, the serum catecholamines were significantly increased 20 or 120 min after antigen injection. The highest serum cathecholamine values were obtained in animals which were selected during a severe state of protracted shock, and in those which died in protracted shock. Antihistamine pretreatment reduced the serum noradrenaline, but not the adrenaline values in anaphylaxis. In urethane anesthesia, the anaphylactic serum catecholamine levels (especially noradrenaline) were lower than in nonanesthetized animals. The adrenaline and noradrenaline content of the adrenals in protracted and in acute anaphylactic shock did not differ from control values.