Decreased Serum Selenium Levels are Correlated with Diminished Coronary Flow Reserve Among Hemodialysis Patients

Cardiovascular diseases are the main reason of high mortality among hemodialysis patients. Decreased serum selenium levels may have a role in accelerated atherosclerosis in this patient group. The hypothesis of this study was to show a correlation between decreased serum selenium levels and coronary flow reserve as an indicator of endothelial dysfunction and atherosclerosis in HD patients. Seventy-one chronic hemodialysis patients and age 65 and sex-matched healthy controls were included in the study. Plasma selenium levels were measured by spectrophotometry, and coronary flow reserve was assessed by transthoracic Doppler echocardiography. Serum selenium levels (34.16?±?6.15 ng/ml vs. 52.4?±?5.51 ng/ml, P?<?0.001) and coronary flow reserve values (1.73?±?0.11 vs. 2.32?±?0.28, P?<?0.001) were significantly lower in hemodialysis patients compared with controls, respectively. There was a significant positive correlation between coronary flow reserve and serum levels of selenium (r?=?0.676, P?<?0.001). A linear regression analysis showed that serum levels of selenium were independently and positively correlated with coronary flow reserve (regression coefficient?=?0.650, P?<?0.05). This study was the first to show a positive and independent correlation between decreased selenium levels and diminished coronary flow reserve as an indicator of endothelial dysfunction and atherosclerosis in hemodialysis patients. Our data suggest that decreased serum selenium levels may facilitate the development of endothelial dysfunction and disruption of coronary flow reserve which occur before the development of overt atherosclerosis.     

Analysis of the sphingomyelin phosphodiesterase 1 gene (SMPD1) in Turkish Niemann–Pick disease patients: Mutation profile and description of a novel mutation

Niemann–Pick disease (NPD) is a lysosomal storage disorder that results from the deficiency of a lysosomal enzyme, acid sphingomyelinase. Niemann–Pick disease type A and B is caused by mutations in the sphingomyelin phosphodiesterase gene (SMPD1) coding for ASM. The aim of this study was to evaluate the spectrum of SMPD1 gene mutations in Turkish NPD patients and to study genotype–phenotype associations. We present a molecular analysis of 10 Turkish NPD type A/B patients. Four of the patients had type A and six had type B NPD. All mutant SMPD1 alleles were identified, including 5 different mutations, 1 of which was novel. These mutations included three missense mutations: c.409T>C (p.L137P), c.1262 A>G (p.H421R) and c.1552T>C (p.L549P), a common frameshift mutation in codon 189, identified in three patients, is caused by the deletion of the 567T, introducing a stop codon 65 amino acids downstream (p.P189fsX65), and a novel frameshift mutation c.1755delC (p.P585PfsX24) which was not reported previously.     

Anaerobic digestion of whole stillage from dry-grind corn ethanol plant under mesophilic and thermophilic conditions

Anaerobic digestion of whole stillage from a dry-grind corn-based ethanol plant was evaluated by batch and continuous-flow digesters under thermophilic and mesophilic conditions. At whole corn stillage concentrations of 6348 to 50,786 mg total chemical oxygen demand (TCOD)/L, at standard temperature (0 °C) and pressure (1 atm), preliminary biochemical methane potential assays produced 88 ± 8 L (49 ± 5 L CH₄) and 96 ± 19 L (65 ± 14 L CH₄) biogas per L stillage from mesophilic and thermophilic digesters, respectively. Continuous-flow studies for the full-strength stillage (TCOD = 254 g/L) at organic loadings of 4.25, 6.30 and 9.05 g TCOD/L days indicated unstable performance for the thermophilic digester. Among the sludge retention times (SRTs) of 60, 45 and 30 days tested, the mesophilic digestion was successful only at 60 days-SRT which does not represent a practical operation time for a large scale bioethanol plant. Future laboratory studies will focus on different reactor configurations to reduce the SRT needed in the digesters.     

Mathematical modeling of the malignancy of cancer using graph evolution

We report a novel computational method based on graph evolution process to model the malignancy of brain cancer called glioma. In this work, we analyze the phases that a graph passes through during its evolution and demonstrate strong relation between the malignancy of cancer and the phase of its graph. From the photomicrographs of tissues, which are diagnosed as normal, low-grade cancerous and high-grade cancerous, we construct cell-graphs based on the locations of cells; we probabilistically generate an edge between every pair of cells depending on the Euclidean distance between them. For a cell-graph, we extract connectivity information including the properties of its connected components in order to analyze the phase of the cell-graph. Working with brain tissue samples surgically removed from 12 patients, we demonstrate that cell-graphs generated for different tissue types evolve differently and that they exhibit different phase properties, which distinguish a tissue type from another.     

State of the art in the functioning of shallow Mediterranean lakes: workshop conclusions

Studies on shallow lakes from the north temperate zone show that they alternate between clear and turbid water states in response to control factors. However, the ecology of semi-arid to arid shallow Mediterranean lakes is less explored. Hydrological effects (e.g. water level fluctuations, water residence time) on major ions and nutrient dynamics and processes, and ecology of submerged macrophytes appear to have a crucial role for food webs in shallow Mediterranean lakes. Nutrient control may be of greater priority in eutrophicated warm shallow lakes than in similar lakes at higher latitudes. This will be relevant for the implementation of the European Water Framework Directive, and conservation and management of these ecosystems. Strong trophic cascading effects of fish resulting from dominance of omnivorous and benthivorous fish species, whose diversity is usually high, together with frequent spawning and absence of efficient piscivores, seem to be the reason for the lack of large-bodied grazers that could control phytoplankton. However, such effects may vary within the region depending on fish distribution and community. These factors need elaboration in order to allow shallow lake ecologists and managers to develop better restoration strategies for eutrophicated shallow Mediterranean lakes. Consequently, modifications for the implementation of the European Water Framework Directive for determining ecological status in shallow Mediterranean lakes appear to be necessary. Furthermore, the implications of climate warming may be even more challenging than in high latitude lakes since shallow lakes in the Mediterranean region are among the most sensitive to extreme climate changes. There is an urgent need for data on the ecology of shallow lakes in the region. An appeal is made for international cooperation, development of large-scale research and information exchange to facilitate this and a web-based discussion list has been implemented.     

Photophysical and photodynamic properties of Pyronin Y in micellar media at different temperatures

In this study, photophysics and photodynamical properties of Pyronin Y (PyY) in different liquid media were investigated. Interactions of PyY, which is a positively charged pigment compound pertaining to the xanthene derivatives with surfactants possessing distinct charges, were determined by using the molecular absorption and fluorescence spectroscopy techniques. It was observed that band intensities of absorption and fluorescence spectra belonging to PyY increase in proportion to the water when compared to three micelle systems, cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and Triton X‐100 (TX‐100). This suggests that interactions in micelle systems are different from those in deionized water, and solvation and surface interactions modify. It is determined that the strongest interaction occurs between PyY dye and SDS, anionic surfactant, and this interaction arises from the electrostatic forces. Calculated photophysical parameters indicated that the microenvironment of PyY in SDS micelle is different to that of other systems. In temperature studies, it was reported that increasing the temperature of the samples increased non‐radiative transitions. Steady‐state fluorescence anisotropy values were calculated by using fluorescence intensities of PyY compound in pre‐micellar, micellar and post‐micellar systems. Once the PyY fluorescence probe is added to the surfactant containing solutions below the critical micelle concentrations, the measured anisotropy values were found to be low because the probe remains in the deionized water phase. When the surfactant concentration of the medium becomes closer to the critical micelle concentrations, the steady‐state anisotropy value prominently increases. This is because of the restrictions on the rotational diffusion of the probe in micellar solution. It is observed that positively charged PyY shows a higher affinity to the negatively charged SDS compared with the positively charged CTAB and neutral TX‐100 surfactants. This can be explained by Coulombic interactions.     

The missing “link”: an autosomal recessive short stature syndrome caused by a hypofunctional XYLT1 mutation

Proteoglycan (PG) synthesis begins with the sequential addition of a “linker chain”, made up of four sugar residues, to a specific region of a core protein. Defects in the enzymes catalyzing steps two to four of the linker chain synthesis have been shown to cause autosomal recessive human phenotypes while no mutation has yet been reported in humans for the xylosyltransferases 1 and 2 (XT1 and XT2), the initiating enzymes in the linker chain formation. Here, we present a consanguineous Turkish family with two affected individuals presenting with short stature, distinct facial features, alterations of fat distribution, and moderate intellectual disability. X-rays showed only mild skeletal changes in the form of a short femoral neck, stocky and plump long bones and thickened ribs. Using a combination of whole-exome sequencing (WES), determination of homozygous stretches by WES variants, and classical linkage analysis, we identified the homozygous missense mutation c.C1441T in XYLT1, encoding XT1, within a large homozygous stretch on chromosome 16p13.12-p12.1. The mutation co-segregated with the phenotype in the family, is not found in over 13,000 alleles in the exome variant server and is predicted to change a highly conserved arginine at position 481 (p.R481W) located in the putative catalytical domain. Immunostaining of primary patient fibroblasts showed a loss of predominance of Golgi localization in mutant cells. Moreover, western blot analysis of decorin in cell culture supernatant demonstrated glycosylation differences between patient and control cells. Our data provide evidence that functional alterations of XT1 cause an autosomal recessive short stature syndrome associated with intellectual disability.     

The genes encoding cAMP-dependent protein kinase catalytic subunit homologues of the microsporidia Encephalitozoon intestinalis and E. cuniculi: molecular characterisation and phylogenetic analysis

A gene encoding a protein kinase was identified by homology-based PCR amplification in Encephalitozoon intestinalis, a microsporidian parasite pathogenic to humans, and its orthologue has been identified by database mining in the genome of the related species E. cuniculi, whose sequence has been recently published. Phylogenetic analysis revealed that the proteins encoded by these genes are homologues of the cAMP-dependent protein kinase catalytic subunits (PKAc). Southern blot analysis indicated that the EiPKAc gene is present in two copies in the E. intestinalis genome, whereas the E. cuniculi orthologue (EcPKAc) is a single copy gene. RT-PCR data showed that the EiPKAc gene is expressed in at least one of the intracellular stages during infection of the mammalian host cell by E. intestinalis.