New piperidine-based derivatives as sigma receptor ligands. Synthesis and pharmacological evaluation

The sigma receptor (σR) family has been considered mysterious for a long time. In fact, the σ2R subtype has been cloned only recently, revealing its identity as TMEM97, a NPC1-binding protein involved in cholesterol biosynthesis and implicated in the pathogenesis of cancer and neurologic disorders. With the aim of developing new chemical entities gifted with σR affinity, herein we report the design and synthesis of new piperidine-based alkylacetamide derivatives with mixed affinity towards both σ1 and σ2R subtypes.     

Variability of the immunoglobulin heavy chain constant region locus: a population study

The Immunoglobulin Heavy chain Constant region (IGHC) locus is a multigene family composed of highly homologous segments often involved in unequal crossings over that lead to deleted and duplicated haplotypes. The frequencies of these haplotypes in 558 individuals from Lombardy, Veneto, Puglia and Sardinia were determined by Pulsed Field Gel Electrophoresis (PFGE), followed by Southern blotting with four IGHC probes, and compared with those observed in 110 subjects from Piedmont. Twenty deletions and 60 duplications were characterized, all in heterozygous individuals except for 2 homozygous deletions. The differences in frequency between the five populations were not significant. The deletions/duplications involved one or more genes: GP-A2, A1-E and G4 duplications, and A1-E and GP-A2 deletions were the most common. Four new duplications are described: three, involving the genes from GP to A2, from G2 to G4, and G4, are counterparts of known deletions. The fourth duplication spans from GP to G2. A G1 deleted heterozygous individual never previously described in Italy is reported. All the rearranged haplotypes seem to be the result of unequal crossing over. The difference between the number of duplications and deletions was significant in Sardinia, Lombardy, Puglia and in the total of 668 subjects (P < 0.001). This may be due to selection or genetic drift.     

Identification of lectin binding sites in the rat brain

Lectins belong to a class of proteins or glycoproteins able to bind carbohydrates. The study reported here describes the identification of lectin-binding sites in the adult rat brain. The results indicate that among the 31 lectins utilized, eight show a specific positive reaction with neurons. Staining was also observed with other cerebral structures such as myelin, leptomeninges, choroid plexus and capillaries. Lectins are, therefore, an important histochemical tool and can be easily and reliably used for the identification of cells and cerebral structures in the adult rat brain.Abbreviations Gal galactose - Fuc fucose - Man mannose - GalNAc N-acetylgalactosamine - GlcNAc N-acetylglucosamine - NeuNAc sialic acid     

Characterisation of the serotonin efflux induced by cytosolic Ca2+ and Na+ concentration increase in human platelets.

BACKGROUND/AIM: The present study aimed at elucidating the mechanism(s) of serotonin (5-HT) efflux induced by thapsigargin from human platelets in the absence of extra-cellular Ca2+. METHODS: Efflux of pre-loaded radiolabeled serotonin was generally determined by filtration techniques. Cytosolic concentrations of Ca2+, Na+ and H+ were measured with appropriate fluorescent probes. RESULTS: 5-HT efflux from control or reserpine-treated platelets--where reserpine prevents 5-HT transport into the dense granules--was proportional to thapsigargin evoked cytosolic [Ca2+]c increase. Accordingly factors as prostacyclin, aspirin and calyculin which reduced [Ca2+]c-increase also inhibited the 5-HT efflux. Thapsigargin, which also caused a remarkable increase in cytosolic [Na+]c, promoted less 5-HT release, in parallel to lower [Na+]c and [Ca2+]c increase, when added to platelet suspensions containing low [Na+]. The Na+/H+ exchanger monensin increased the [Na+]c and induced 5-HT efflux without affecting the Ca2+ level. The 5-HT efflux induced by both [Ca2+] or [Na+]c increase did not depend on pH or membrane potential changes, whereas it decreased in the absence of extra-cellular K+, and increased in the absence of Cl- or Na+. CONCLUSION: Increases in [Ca2+]c and [Na+]c independently induce serotonin efflux through the outward directed plasma membrane serotonin transporter SERT. This event might be physiologically important at the level of capillaries or narrowed arteries where platelets are subjected to high shear stress which causes [Ca2+]c increase followed by 5-HT release which might exert vasodilatation.     

Impact of a flood event on the zooplankton of an estuarine lake

Shallow coastal lakes are prone to large fluctuations in physico-chemical variables such as salinity and turbidity. This is now escalating in response to global change. A flood event in March 2014 resulted in a silt plume spreading through part of Lake St Lucia (South Africa). To determine the impact of this event on zooplankton, the Narrows region of St Lucia was sampled on a monthly basis from March to September 2014. For comparative purposes, data from samples collected prior to the flood event were included in the analyses. Analysis of similarity (ANOSIM) revealed dissimilarities in zooplankton community structure among the sampling occasions. The March 2014–May 2014 period was characterized by the highest abundance of freshwater species. Conversely, the abundance of the resident St Lucia copepods Acartiella natalensis and Oithona brevicornis was lowest during this time, and highest in September 2014. The other dominant copepod Pseudodiaptomus stuhlmanni prevailed in March 2014, but declined markedly in April. As of September 2014, P. stuhlmanni had yet to regain its pre-flood densities. The BIOENV procedure, which relates biological and environmental data, revealed that turbidity, salinity and dissolved oxygen were responsible for the observed changes in zooplankton community structure during the study period. Careful management of turbidity and salinity is stressed, as both factors are major drivers of the biota of St Lucia and similar systems worldwide.     

Lack of correlation between DNA-methylating activity and appearance of the immunogenic phenotype in clones of a murine lymphoma treated with mutagens

Summary The relationship between induction of novel immunogenicity by xenogenizing chemicals and DNA-methylating activity in murine tumors was investigated at the clonal level in L1210Ha cells treated with 5-azacytidine, N-methyl-N-nitro-N-nitrosoguanidine (MNNG) or 1-(p-chlorophenyl)-3,3-dimethyltriazene (DM-Cl). Cells were exposed to the drugs in vitro, cloned by limiting dilution, and assayed for transplantation immunogenicity and 5-methylcytosine content. The results showed that 0% (0/29, 5-azacytidine), 6.8% (2/29, MNNG) and 87.5% (28/32, DM-Cl) of the resulting clones were highly immunogenic, as judged by their tumorigenicity in intact compared to immunodepressed hosts. Frequency distribution analysis of the 5-methylcytosine content of drug-treated and parental clones showed that the methylation pattern was not significantly modified by tumor exposure to either 5-azacytidine or MNNG, and the two immunogenic clones induced by MNNG had methylcytosine levels very close to the 50th percentile value. In contrast, the extent of DNA methylation was increased in the cells treated with DM-Cl, but no obvious association was found between methylation status and immunogenicity of the drug-treated clones. In four 5-azacytidine-treated clones that displayed little or no immunogenicity, additional rounds of drug exposure led to progressive DNA demethylation, but failed, as a rule, to enhance tumor cell immunogenicity. Taken together, the present data indicate that, at least for the examined tumor, immunogenic variants are generated by mutagen treatment at high (MNNG) or very high (DM-Cl) frequencies under conditions in which hypomethylation-induced antigen amplification is unlikely.This work was supported by Progetto Finalizzato Oncologia, C. N. R, Rome-Italy, grant no. 87.01423.44 Abbreviations used: MNNG, N-methyl-N-nitro-N-nitrosoguanidine; DM-Cl, 1-(p-chlorophenyl)-3,3-dimethyltriazene; MST, difference (days) between median survival times of intact and irradiated mice injected with the same cells.