Genetic differentiation of Elysia timida (Risso, 1818) populations in the Southwest Mediterranean and Mar Menor coastal lagoon

Genetic variation at 10 enzyme loci was analysed in Elysia timida sacoglossan mollusc samples, originating from both coastal lagoon and marine sites. The observed heterozygosity ranged from 0.390 (Los Urrutias) to 0.277 (Tabarca). Marine and coastal lagoon populations were characterised by exclusive alleles.     

Substance P affects the GABAergic system in the hypothalamo-pituitary axis

In the present work we examined the effect of the neutralization of endogenous substance P by the administration of an anti-substance P serum (ASPS) on GABA concentration in the anterior pituitary in hyperprolactinemic conditions induced by 5-hydroxytryptophan or by grafting anterior pituitaries. ASPS reduced the increase in the anterior pituitary GABA concentration induced by hyperprolactinemia. In vitro experiments showed that substance P inhibited K⁺-evoked GABA efflux from hypothalamic fragments and decreased GABA concentration in the anterior pituitary but ASPS increased it. Our results demonstrate that substance P modifies hypothalamic GABA release and anterior pituitary GABA concentration and suggest that an interaction exists between substance P and GABA.     

Fine structure of the spermatozoa of Crassostrea gigas (Mollusca,Bivalvia)

We describe sperm ultrastructure and acrosome differentiation during spermiogenesis in Crassostrea gigas (Mollusca Bivalvia). The sperm cell is a uniflagellated cell of the primitive type. The head region contains a rounded or conical nucleus surmounted by small acrosome. This organelle consists of a membrane-bound acrosomal granule, the contents of which have a homogeneous density, except in the anterior region, which is positive for PTA. The acrosome also surrounds the perforatorium, which includes oriented fibrillar elements: this is the axial body. The middle piece contains four mitochondria encircling two perpendicular centrioles. The distal centriole is provided with a system of mechanical fixation to the plasma membrane, consisting of nine fibers in radial arrangement. The tail flagellum, about 50 m?m long, contains the usual microtubular axoneme. © 1993 Wiley-Liss, Inc.     

Mevalonate dependency of the early cell cycle mitogenic response to epidermal growth factor and prostaglandin F2α in Swiss mouse 3T3 cells

Lovastatin (LOV), a hydroxy-methylglutaryl-coenzyme A (HMGCoA) reductase competitive inhibitor, blocks epidermal growth factor (EGF)— or prostaglandin F_2α (PGF_2α)—induced mitogenesis in confluent resting Swiss 3T3 cells. This inhibition occurs even in the presence of insulin, which potentiates the action of these mitogens in such cells. LOV exerts its effect in a 2–80 μM concentration range, with both mitogens attaining 50% inhibition at 7.5 μM. LOV exerted its effect within 0–8 h following mitogenic induction. Mevanolactone (10–80 μM) in the presence of LOV could reverse LOV inhibition within a similar time period. LOV-induced blockage of PGF_2α response is reflected in a decrease in the rate of cell entry into S phase. Neither cholesterol, ubiquinone, nor dolichols of various lengths could revert LOV blockage. In EGF- or PGF_2α-stimulated cells, LOV did not inhibit [³H]leucine or [³H]mannose incorporation into proteins, while tunicamycin, an inhibitor of N′ glycosylation, prevented this last phenomenon. Thus, it appears that LOV exerts its action neither by inhibiting unspecific protein synthesis nor by impairing the N′ glycosylation process. These findings strongly suggest that either EGF or PGF_2α stimulations generate early cell cycle signals which induce mevalonate formation, N′ glycoprotein synthesis, and proliferation. The causal relationship of these events to various mechanisms controlling the onset of DNA synthesis is also discussed. © 1995 Wiley-Liss, Inc.     

Strategy for fluorescent labeling of human acidic fibroblast growth factor without impairment of mitogenic activity: A bona fide tracer

Here we describe, for the first time, the design and characterization of a bona fide fluorescently labeled mutant of the human acidic fibroblast growth factor (aFGF). The aFGF–Cys2 mutant was recombinantly synthesized by substituting the second amino acid with a reactive cysteine whose sulfhydryl group’s side chain reactivity facilitated the covalent binding of a fluorescent probe as a thiolyte monobromobimane. Using a combination of biophysical and functional assays, we found that the fluorescently labeled mutant aFGF is characterized by essentially the same global folding, mitogenic activity, and association behavior with heparin, its physiological activator, as the unlabeled wild-type protein. We used this new tracer protein mutant to determine the association behavior of aFGF with heparin in the presence of high concentrations of albumin that mimicked more closely the plasma medium in which aFGF is naturally located and in which it has evolved to function. By exposing the aFGF–Cys2–heparin complex to increasing concentrations of albumin up to physiological plasma levels, we were able to demonstrate that macromolecular crowding does not affect the stoichiometry of the interaction. In summary, the dimeric aFGF–Cys2–heparin complex might represent a biologically relevant complex in physiological media.     

Intrathecal administration of autologous mesenchymal stromal cells for spinal cord injury: Safety and efficacy of the 100/3 guideline

Background aims

Cell therapy with autologous mesenchymal stromal cells (MSCs) in patients with spinal cord injury (SCI) is beginning, and the search for its better clinical application is an urgent need.

Heme Oxygenase-1 (HO-1) Expression in Prostate Cancer Cells Modulates the Oxidative Response in Bone Cells

Prostate cancer (PCa) is a leading cause of death among males. It is currently estimated that inflammatory responses are linked to 15-20% of all deaths from cancer worldwide. PCa is dominated by complications arising from metastasis to the bone where the tumor cells interact with the bone microenvironment impairing the balance between bone formation and degradation. However, the molecular nature of this interaction is not completely understood. Heme oxygenase-1 (HO-1) counteracts oxidative damage and inflammation. Previous studies from our laboratory showed that HO-1 is implicated in PCa, demonstrating that endogenous HO-1 inhibits bone derived-prostate cancer cells proliferation, invasion and migration and decreases tumor growth and angiogenesis in vivo. The aim of this work was to analyze the impact of HO-1 modulated PCa cells on osteoblasts proliferation in vitro and on bone remodeling in vivo. Using a co-culture system of PC3 cells with primary mice osteoblasts (PMOs), we demonstrated that HO-1 pharmacological induction (hemin treatment) abrogated the diminution of PMOs proliferation induced by PCa cells and decreased the expression of osteoclast-modulating factors in osteoblasts. No changes were detected in the expression of genes involved in osteoblasts differentiation. However, co-culture of hemin pre-treated PC3 cells (PC3 Hem) with PMOs provoked an oxidative status and activated FoxO signaling in osteoblasts. The percentage of active osteoblasts positive for HO-1 increased in calvarias explants co-cultured with PC3 Hem cells. Nuclear HO-1 expression was detected in tumors generated by in vivo bone injection of HO-1 stable transfected PC3 (PC3HO-1) cells in the femur of SCID mice. These results suggest that HO-1 has the potential to modify the bone microenvironment impacting on PCa bone metastasis.     

Imidazolidines as new anti-Trypanosoma cruzi agents: biological evaluation and structure-activity relationships

Imidazolidine derivatives were studied as anti-Trypanosoma cruzi agents. Imidazolines can be considered as ethylenediamine/carbonyl precursors and therefore interfere with the biosynthesis of polyamines into the parasite. Some of the derivatives were found to have high and selective activity against the proliferative stages of the parasite, with IC(50) values against the epimastigote form in the low micromolar range as the reference drug Nifurtimox. The imidazolidines demonstrated to be stable after five days of incubation in buffer glucose, pH 7, indicating that diamines were not obtained in these conditions. But it was found that two of the studied diamine precursors were as active as the parent compounds. Probably, the imidazolidines affect the mitochondrial integrity according to the excreted end-products found in the NMR studies. The QSAR studies indicated that the bioactivities are correlated with the lipophilicities. In conclusion, we have described a new and relevant bioactivity for imidazolidines. The results support further in vivo studies of some of these imidazolidine derivatives.