Behavioural and morphological effects of testosterone and gonadotropins in the young male domestic duck (Anas platyrhynchos L.)

Young male domestic ducks 20–72 days old were successively injected with two hormonal preparations. The first hormone treatment included males injected with testosterone propionate (TP), human chorionic gonadotropin (HCG), pregnant mare serum (PMS), control oil injected males (C) and males injected with TP and submitted at the same time to a permanent intense light. During the second hormonal treatment all males except controls were injected with TP.Almost no behavioural effects were observed in any group of males following the first treatment. The second one, however, induced intense social display and sexual behaviour in the four TP-injected groups. Some qualitative and quantitative differences were found between groups according to the first hormone treatment to which they had been submitted. This suggests a possible role of gonadotropic hormones in the control of social behaviour in ducks. Experimental data supporting this hypothesis are briefly reviewed and discussed.     

Barley γ3-hordein: Glycosylation at an atypical site,disulfide bridge analysis,and reactivity with IgE from patients allergic to wheat

Post translational modifications of a seed storage protein, barley γ3-hordein, were determined using immunochemical and mass spectrometry methods. IgE reactivity towards this protein was measured using sera from patients diagnosed with allergies to wheat. N-glycosylation was found at an atypical Asn-Leu-Cys site. The observed glycan contains xylose. This indicates that at least some γ3-hordein molecules trafficked through the Golgi apparatus. Disulfide bridges in native γ3-hordein were almost the same as those found in wheat γ46-gliadin, except the bridge involving the cysteine included in the glycosylation site. IgE reacted more strongly towards the recombinant than the natural γ3-hordein protein. IgE binding to γ3-hordein increased when the protein sample was reduced. Glycosylation and disulfide bridges therefore decrease epitope accessibility. Thus the IgE from patients sensitized to wheat cross-react with γ3-hordein due to sequence homology with wheat allergens rather than through shared carbohydrate determinants.     

Subcellular fractionation of striatum: Sedimentation properties of dopaminergic synaptosomes

Linear sucrose density gradient centrifugation of a crude synaptosomal-mitochondrial preparation of rat striatum was performed at 82, 500g for 7.5, 15 and 30 min and 1, 4 and 20 h. After centrifugation various marker enzyme activities were measured throughout the gradients, viz. tyrosine hydroxylase (TH) and DOPA decarboxylase (DD) as markers of dopaminergic synaptosomes, lactate dehydrogenase (LDH) as a general synaptosomal marker and monoamine oxidase (MAO) as a mitochondrial marker. At all centrifugation times the distribution patterns of TH and DD activity coincided almost perfectly. Notable differences were found between the sedimentation properties of these TH/DD-containing particles and LDH-containing particles: TH and DD were symmetrically distributed in the gradient much sooner than LDH, at all centrifugation times the top of the TH and DD curves was lying deeper in the gradient than the highest LDH activity, and Th and DD became enriched in the gradients to a much greater extent than LDH. It is concluded that rat striatal dopaminergic synaptosomes form a relatively homogenous population of particles sedimenting faster into the gradients than the bulk of striatal synaptosomes does. This distinct sedimentation behaviour of the dopaminergic synaptosomes can be usefully applied for analytical purposes.     

The 25 kDa protein kinase inhibitor present in liver cell is absent in fast growing HTC cells and is induced in sodium butyrate treated cells

We have recently characterized a cAMP independent protein kinase inhibitor in rat liver. This inhibitor is absent or inactive in fast growing HTC cells and is induced according to exponential kinetics by sodium butyrate, a compound which arrests cell growth at the G1 phase of the cell cycle. It is suggested that the inhibitor could be involved in cell growth regulation.     

Peptidomimetic glutathione analogues as novel gammaGT stable GST inhibitors.

Elevated levels of glutathione-S-transferase (GST) isoenzymes are found in many tumor cells and are thought to play a role in the onset of multidrug resistance (MDR). To evaluate the contribution of GST to this process, inhibitors are needed. Glutathione (GSH) conjugates, although good GST inhibitors, cannot be used in vivo, because they are eliminated rapidly. In this paper, we describe the synthesis of a series of novel peptidomimetic glutathione analogues that are stabilized against peptidase mediated breakdown. The peptide bonds in GSH were replaced by isosteres, such as the 'reduced' amide (which was prepared using a novel method), N-methylamide, urethane, and methylene linkages. The in vitro evaluation of the compounds focuses on GST inhibition and stability towards gamma-glutamyl-transpeptidase (gammaGT), the main enzyme involved in GSH breakdown. The compounds were conjugated to the model electrophile ethacrynic acid (EA) to resemble GS-EA, an efficient GST inhibitor. All novel GSH-analogues were shown to inhibit rat liver cytosolic GSTs. Furthermore, peptidomimetic changes of the gamma-glutamyl-cysteine amide bond greatly improved stability towards gammaGT. These compounds may therefore be useful in the design of novel in vivo applicable GST inhibitors.     

Further characterization of cytotoxic T cells generated by short-term culture of human peripheral blood lymphocytes with interleukin-2 and anti-CD3 mAb

 In this study we have specifically investigated the participation of T cells in the cytotoxic activity of peripheral blood lymphocytes (PBL) activated by interleukin-2 (IL-2, 50 U/ml) alone or in combination with an anti-CD3 mAb (BMA030, 10 ng/ml, IgG2a). Purified CD3⁺ T cells, incubated in the presence of the anti-CD3 mAb for 4 days, mediated a cytotoxic activity against HL60 and U937 tumor cell lines. Several findings suggested the involvement of a redirected-cytotoxicity phenomenon, since the lytic process was restricted to target cell lines bearing the high-affinity Fcγ receptor (FcγRI) and T lymphocytes stimulated by IL-2 alone did not lyse these cell lines. Furthermore, anti-CD3 mAb F(ab′)₂, anti-CD3 IgG1 (UCHT1), phytohemagglutinin or staphylococcal enterotoxin A did not induce a similar cytotoxic activity in T lymphocytes. The cytotoxic process occurred in the presence of a very low level of anti-CD3 antibodies (in the nanomolar range). The cytotoxic activity of T cells stimulated by IL-2 or by IL-2 + BMA030, against OVCAR-3 cells (MOv18⁺ ovarian tumor cell line), was also compared in the presence of a bispecific antibody (OC/TR, anti-CD3 × MOv18). The stimulation by IL-2 + BMA030 induced approximately a twofold higher cytotoxic activity than IL-2-activated T cells. This could be related to the state of activation of effector cells stimulated by IL-2 + BMA030, since the phenotypic analysis showed an increased proportion of T cells expressing several activation/differentiation markers (CD25, HLA-DR, CD45R0, adhesion molecules). These findings could be applied to the design of therapeutic protocols using anti-CD3 ×antitumoral bispecific antibodies. Received: 6 December 1995 / Accepted: 4 June 1996     

Nouvelle méthode de préparation du 5-hydroxyméthyl-2-furaldéhyde par action de sels d'ammonium ou d'immonium sur les mono-, oligo- et poly-saccharides. Accès direct aux 5-halogénométhyl-2-furaldéhydes

In a new and simple process for preparing 5-hydroxymethyl-2-furaldehyde from mono-, oligo- and poly-saccharides, which uses immonium or ammonium salts, direct heating of the reagent and the starting material, both in solid phase, gave directly 5-hydroxymethyl-2-furaldehyde with a good purity, avoiding production of secondary products. The use of a polymeric form of the reagent constitutes an extension of the method toward an eventual industrial application. Under special conditions, a one-pot dehydration—halogenation sequence gave 5-bromomethyl-(or 5-chloromethyl)-2-furaldehyde.