Comparative in vitro and in vivo beta-oxidation of N-nitrosodiethanolamine in different animal species

The metabolism of N-nitrosodiethanolamine (NDELA) was studied to assess whether the formation of the beta-oxidated metabolites N-(2-hydroxyethyl)-N-(formylmethyl)nitrosamine (EFMN) and N-(2-hydroxyethyl)-N-(carboxymethyl)nitrosamine (ECMN) is involved in the mechanism of tumor induction in various animal species with different susceptibility to NDELA carcinogenicity. In vitro studies using liver S9 fractions from rats, hamster, B6C3F1 and CD-1 mice and rabbits showed that all the animal species metabolize NDELA through the beta-oxidation pathway, although to different extents. Urinary excretion of NDELA and its metabolite ECMN in rats, hamsters and mice after 5 mg X kg-1 NDELA i.p. confirmed these findings. The results suggest there is no correlation between carcinogenesis by NDELA and its beta-oxidation. The possibility that ECMN formation might represent a detoxifying metabolic pathway for NDELA is discussed.     

Release of diamine oxidase into plasma by glycosaminoglycans in rats

Plasma diamine oxidase (DAO) values are enhanced by intravenous injection of heparin which releases the enzyme, synthesized in small bowel enterocytes, from binding sites located on endothelial cells of the intestinal microvasculature. Intestinal DAO, in analogy with lipoprotein lipase (another heparin-released enzyme), is believed to be electrostatically linked to endothelial binding sites composed of a glycosaminoglycan (GAG) which is presumably heparan sulphate, but the complete mechanism of enzyme release is not known. In this study we assayed in rats the DAO-releasing capability of heparan sulphate, dermatan sulphate, chondroitin sulphate A and hyaluronic acid, all heparin related compounds. Heparan sulphate, a compound with the same hexosamine as heparin but with a lower concentration of sulphated iduronic acid, induced a very high release of DAO (3-fold less than heparin), while the other tested GAGs, composed of higher proportions of non sulphated uronic acid and with galactosamine instead of glucosamine, induced a significantly lower release. In rats treated with 60 mg heparan sulphate the significant decrease in ileal mucosal DAO activity indicates that, in analogy with heparin, the high plasma enzymatic activity induced is of enterocytic origin. It is suggested that the high charge density of the compounds tested, due to the degree of sulphatation, is the decisive factor in promoting the release of intestinal DAO.     

Metabolism of thromboxane B2 in the isolated perfused rat kidney: mass spectrometric identification of urinary products

The metabolism of thromboxane B2 (TXB2), the stable breakdown product of thromboxane A2, has been studied in isolated perfused kidney preparations using a recirculating system. In a first experiment, TXB2 was infused at a rate of 20 micrograms/kg per min. In a second experiment, a 1:1 mixture of TXB2 and octadeuterated TXB2 (0.4 microgram/kg per min each) was infused. Urinary samples collected during the infusion of TXB2 or vehicle were extracted on C18 cartridges and derivatized to methyl or pentafluorobenzyl ester, methyloxime, trimethylsilyl ether. Samples were analyzed by high-resolution gas chromatography-mass spectrometry in the electron impact and negative ion chemical ionization modes. Products of beta-oxidation, reduction of the delta 5,6 double bond and dehydrogenation at C-11 (2,3-dinor-TXB2, 2,3-dinor-TXB1, 2,3,4,5-tetranor-TXB1 and 11-dehydro-TXB2) were identified in addition to unmetabolized TXB2. 2,3,4,5-tetranor-TXB1 and 2,3-dinor-TXB1 were the most abundant metabolites.     

Monoclonal antibodies against pertussis toxin subunits

Abstract Twenty monoclonal antibodies (mAbs) reacting with cholera toxin (CT) of Vibrio cholerae strain 569B were characterized in cross-section and G_M1 ganglioside inhibition assays. MAbs were characterized by reaction with CT and Escherichia coli heat-labile porcine strain (LT_p) and human strain (LTh) enterotoxins, and by G_M1 ganglioside inhibition of mAb binding. Eight of 10 CT-A specific and 3 of 10 CT-B-specific mAbs cross-reacted with LTh and LTp. G_M1 ganglioside inhibited reactions of the CT-B cross-reacting antibodies. Results showed that these epitodes common to the B subunit of CT and LT are located in or near the G_M1 ganglioside binding region, and that the G_M1 ganglioside-binding region of LT differs from that of CT.     

Diffusione pollinica e caratteristiche immunologiche e broncoreattive di soggetti atopici in Pietra Ligure (Savona)

Riassunto Sono state rilevate durante un monitoraggio aerobiologico effettuato a Pietra Ligure (Savona) nel corso del 1987 le concentrazioni polliniche di 50 taxa ed è stata valutata l'influenza relativa dei fattori meteorologici. Le osservazioni palinologiche sono state rapportate alle concentrazioni sieriche delle IgE specifiche, alla reattività bronchiale specifica ed aspecifica valutate in 101 pazienti allergici (rinitici ed asmatici), sensibilizzati a Graminaceae ed Urticaceae (Parietaria) al fine di riconoscere correlazioni tra le caratteristiche aerobiologiche di questi allergeni edi meccanismi patogenetici che sostengono la reattività bronchiale.      

Incidence of sensitisation to the pollens of urticaceae (Parietaria), Poaceae and Oleaceae (Olea europea) and pollen rain in Liguria (Italy)

Summary The authors examined 734 sensitised patients living in four localities in Liguria (Genoa, Savona, Pietra Ligure and Sanremo). The commonest source of sensitisation (62.7%) was Urticaceae (Parietaria), followed by Poaceae (52.5%) andOlea europaea L. (24.0%). A survey of airborne pollens revealed a greater presence of Urticaceae and Poaceae in Genoa and of Oleaceae in Pietra Ligure and Sanremo.     

Presence of a drifting algal bed in the Mar Piccolo basin,Taranto (Ionian Sea,Southern Italy)

A survey is reported of the drifting algal community in Mar Piccolo, a polluted basin subject to sewage outlets. The key role was played by a few key species, mainly floridean red algae.