Neuroprotective effect of pyruvate and oxaloacetate during pilocarpine induced status epilepticus in rats

Recent research data have shown that systemic administration of pyruvate and oxaloacetate causes an increased brain-to-blood glutamate efflux. Since increased release of glutamate during epileptic seizures can lead to excitotoxicity and neuronal cell death, we tested the hypothesis that glutamate scavenging mediated by pyruvate and oxaloacetate systemic administration could have a neuroprotective effect in rats subjected to status epilepticus (SE). SE was induced by a single dose of pilocarpine (350mg/kgi.p.). Thirty minutes after SE onset, a single dose of pyruvate (250mg/kgi.p.), oxaloacetate (1.4mg/kgi.p.), or both substances was administrated. Acute neuronal loss in hippocampal regions CA1 and hilus was quantitatively determined five hours after SE onset, using the optical fractionator method for stereological cell counting. Apoptotic cascade in the hippocampus was also investigated seven days after SE using caspase-1 and -3 activity assays. SE-induced neuronal loss in CA1 was completely prevented in rats treated with pyruvate plus oxaloacetate. The SE-induced caspase-1 activation was significantly reduced when rats were treated with oxaloacetate or pyruvate plus oxaloacetate. The treatment with pyruvate and oxaloacetate caused a neuroprotective effect in rats subjected to pilocarpine-induced SE.     

GROWTH AND ULTRASTRUCTURAL CHANGES IN DICTYOSPHAERIUM PULCHELLUM EXPOSED TO COPPER (CHLOROCOCCALES,CHLOROPHYCEAE)

In an assay addressing the toxicity of copper to Dictyosphaerium pulchellum, a 48 hours' exposure of axenic cultures of the alga to metal concentrations ranging from 0 to 300 mg L^?1 caused a significant decrease in the growth rate and cell chlorophyll content. Extracellular mucilage remotion by controlled sonication before exposure to copper emphasized chlorophyll content reduction, but not cellular density diminution. Because mucilage acts as a cation interchanger, these results suggested that, during at least the first 48 hours, division rates might be affected by lower Cu⁺² concentrations than chlorophyll content. Ultrastructural observations showed that the normal organization of the chloroplasts was altered; they presented dilated lamellae, irregularly arranged with practically no stacking. Copper precipitates were mainly observed outside the plasmalemma or within the extracellular mucilage. Electron probe microanalysis confirmed these observations, showing only minor precipitates inside the cells.     

Distinct patterns of water and osmolyte control between intertidal (Bunodosoma caissarum) and subtidal (Anemonia sargassensis) sea anemones

Anemones are frequently found in rocky intertidal coasts. As they have highly permeable body surfaces, exposure to the air or to salinity variations inside tidal pools can represent intense osmotic and ionic challenges. The intertidal Bunodosoma caissarum has been compared with the subtidal Anemonia sargassensis concerning their response to air exposure or salinity changes. B. caissarum maintains tissue hydration through mucus production and dome-shape formation when challenged with air exposure or extreme salinities (fresh water or hypersaline seawater, 45 psu) for 1-2h. Upon exposure to mild osmotic shocks for 6h (hyposmotic: 25 psu, or hyperosmotic: 37 psu), B. caissarum was able to maintain its coelenteron fluid (CF) osmolality stable, but only in 25 psu. A. sargassensis CF osmolality followed the external medium in both salinities. Isolated cells of the pedal disc of B. caissarum showed full capacity for calcium-dependent regulatory volume decrease (RVD) upon 20% hyposmotic shock, at least partially involving the release of KCl via K(+)-Cl(-) cotransport, and also of organic osmolytes. Aquaporins (HgCl(2)-inhibited) likely participate in this process. Cells of A. sargassensis showed partial RVD, after 20 min. Cells from both species were not capable of regulatory volume increase upon hyperosmotic shock (20%). Whole organism and cellular mechanisms allow B. caissarum to live in the challenging intertidal habitat, frequently facing air exposure and seawater dilution.     

ADF/cofilin regulates secretory cargo sorting at the TGN via the Ca2+ ATPase SPCA1

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Highlights? ADF/cofilin localizes to the TGN and binds SPCA1 in an actin-dependent manner ? Dynamic actin regulates the activity of the Ca²⁺ pump SPCA1 ? ADF/cofilin facilitates secretory cargo sorting in a Ca²⁺-dependent manner     

State of the science: an update on renal cell carcinoma

Renal cell carcinomas (RCC) are emerging as a complex set of diseases that are having a major socioeconomic impact and showing a continued rise in incidence throughout the world. As the field of urologic oncology faces these trends, several major genomic and mechanistic discoveries are altering our core understanding of this multitude of cancers, including several new rare subtypes of renal cancers. In this review, these new findings are examined and placed in the context of the well-established association of clear cell RCC (ccRCC) with mutations in the von Hippel-Lindau (VHL) gene and resultant aberrant hypoxia inducible factor (HIF) signaling. The impact of novel ccRCC-associated genetic lesions on chromatin remodeling and epigenetic regulation is explored. The effects of VHL mutation on primary ciliary function, extracellular matrix homeostasis, and tumor metabolism are discussed. Studies of VHL proteostasis, with the goal of harnessing the proteostatic machinery to refunctionalize mutant VHL, are reviewed. Translational efforts using molecular tools to elucidate discriminating features of ccRCC tumors and develop improved prognostic and predictive algorithms are presented, and new therapeutics arising from the earliest molecular discoveries in ccRCC are summarized. By creating an integrated review of the key genomic and molecular biological disease characteristics of ccRCC and placing these data in the context of the evolving therapeutic landscape, we intend to facilitate interaction among basic, translational, and clinical researchers involved in the treatment of this devastating disease, and accelerate progress toward its ultimate eradication.     

Circulating biomarkers of response to sunitinib in gastroenteropancreatic neuroendocrine tumors: current data and clinical outlook

After years of limited progress in the treatment of patients with advanced-stage gastroenteropancreatic neuroendocrine tumors (GEP-NETs), strategies using targeted agents have been developed on the basis of increased knowledge of the biology of these tumors. Some of these agents, targeting vascular endothelial growth factor (VEGF) and the mammalian target of rapamycin (mTOR) pathway, have shown efficacy in randomized clinical trials. The tyrosine kinase inhibitor sunitinib and the mTOR inhibitor everolimus have received international approval for the treatment of advanced well differentiated pancreatic NETs after showing survival benefit in randomized phase III trials. There is now an imperative need to identify biomarkers of the biologic activity of such targeted therapies in specific disease contexts, as well as new markers of response and prognosis. This approach may allow rational development of drugs and early identification of patients who may obtain benefit from treatments. In this article, we review recent developments in circulating biomarkers of the clinical benefit of targeted therapies for GEP-NET, including soluble proteins and circulating cells, with an emphasis on sunitinib. No validated molecular biomarkers are yet integrated into clinical practice for sunitinib in NET, although some markers have shown correlation with clinical outcomes and may be implicated in resistance. The VEGF-pathway proteins and interleukin-8 (IL-8) are possibly prognostic in GEP-NET; other possible soluble markers of the activity of sunitinib and everolimus include stromal cell-derived factor 1α, chromogranin A, and neuron-specific enolase. We additionally discuss treatment-induced modulation of circulating endothelial cells and progenitors and subpopulations of cells of the myeloid lineage. These candidate markers should be considered in the development of future combination or sequential therapies.     

Apoptosis of non-parasitised red blood cells in Plasmodium yoelii malaria

Recently, while studying erythrocytic apoptosis during Plasmodium yoelii infection, we observed an increase in the levels of non-parasitised red blood cell (nRBC) apoptosis, which could be related to malarial anaemia. Therefore, in the present study, we attempted to investigate whether nRBC apoptosis is associated with the peripheral RBC count, parasite load or immune response. To this end, BALB/c mice were infected with P. yoelii 17XL and nRBC apoptosis, number of peripheral RBCs, parasitaemia and plasmatic levels of cytokines, nitric oxide and anti-RBC antibodies were evaluated at the early and late stages of anaemia. The apoptosis of nRBCs increased at the late stage and was associated with parasitaemia, but not with the intensity of the immune response. The increased percentage of nRBC apoptosis that was observed when anaemia was accentuated was not related to a reduction in peripheral RBCs. We conclude that nRBC apoptosis in P. yoelii malaria appears to be induced in response to a high parasite load. Further studies on malaria models in which acute anaemia develops during low parasitaemia are needed to identify the potential pathogenic role of nRBC apoptosis.     

Association of the 163A/G and 1181G/C osteoprotegerin polymorphism with bone mineral density.

The aim of the study was to investigate the distribution of 163 A/G osteoprotegerin gene promoter and 1181 G/C osteoprotegerin exon 1 polymorphisms in a group of women with different hormonal status and to analyze their relationship with BMD. Osteoprotegerin polymorphisms and BMD were analyzed in 332 women (69 premenopausal and 263 postmenopausal). BMD was quantified at the lumbar spine (L 2-4), femoral neck, and total hip. Genotyping for the presence of different polymorphisms was performed using the Custom Taqman ((R)) SNP Genotyping assays. There were not significant differences in BMD according to 163 A/G genotype. However, significant differences in lumbar spine BMD were found according to 1181 G/C alleles. Thus, women with CC genotype had significant higher BMD at the lumbar spine than those with GC or GG genotype. No differences were found in femoral neck and total hip BMD. In age-adjusted models, the 1181 G/C OPG polymorphism explained 2.2% of BMD variance at the spine, 0.3% at the femoral neck, and 0.9% at the total hip in the whole group. In the subgroup of premenopausal women, the polymorphism was strongly related to spine BMD, and explained 11.5% of the variance, whereas body weight explained 7.9%. The 1181 G/C polymorphism was associated with lumbar spine BMD in Spanish women. Premenopausal women with the CC genotype had a higher BMD.     

Biomineralization of calcium carbonate in the cell wall of Lithothamnion crispatum (Hapalidiales,Rhodophyta): correlation between the organic matrix and the mineral phase

Over the past few decades, progress has been made toward understanding the mechanisms of coralline algae mineralization. However, the relationship between the mineral phase and the organic matrix in coralline algae has not yet been thoroughly examined. The aim of this study was to describe the cell wall ultrastructure of Lithothamnion crispatum, a cosmopolitan rhodolith‐forming coralline algal species collected near Salvador (Brazil), and examine the relationship between the organic matrix and the nucleation and growth/shape modulation of calcium carbonate crystals. A nanostructured pattern was observed in L. crispatum along the cell walls. At the nanoscale, the crystals from L. crispatum consisted of several single crystallites assembled and associated with organic material. The crystallites in the bulk of the cell wall had a high level of spatial organization. However, the crystals displayed cleavages in the (104) faces after ultrathin sectioning with a microtome. This organism is an important model for biomineralization studies as the crystallographic data do not fit in any of the general biomineralization processes described for other organisms. Biomineralization in L. crispatum is dependent on both the soluble and the insoluble organic matrix, which are involved in the control of mineral formation and organizational patterns through an organic matrix‐mediated process. This knowledge concerning the mineral composition and organizational patterns of crystals within the cell walls should be taken into account in future studies of changing ocean conditions as they represent important factors influencing the physico‐chemical interactions between rhodoliths and the environment in coralline reefs.