Material dependence of 2

Calculations of the material dependence of 2H(d,p)3H cross section and neutron-to-proton branching ratio of d+d reactions have been performed including a concept of the 0+ threshold single particle resonance. The resonance has been assumed to explain the enhanced electron screening effect observed in the d+d reaction for different metallic targets. Here, we have included interference effects between the flat and resonance part of the cross section, which allowed us to enlighten observed suppression of the neutron channel in some metals such as Sr and Li. Since the position of the resonance depends on the screening energy that strongly depends on the local electron density. The resonance width, observed for the d+d reactions in the very hygroscopic metals (Sr and Li) and therefore probably contaminated by oxides, should be much larger than for other metals. Thus, the interference term of the cross section depending on the total resonance width provides the material dependences

Diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is the most common acute hyperglycaemic emergency in people with diabetes mellitus. A diagnosis of DKA is confirmed when all of the three criteria are present — ‘D’, either elevated blood glucose levels or a family history of diabetes mellitus; ‘K’, the presence of high urinary or blood ketoacids; and ‘A’, a high anion gap metabolic acidosis. Early diagnosis and management are paramount to improve patient outcomes. The mainstays of treatment include restoration of circulating volume, insulin therapy, electrolyte replacement and treatment of any underlying precipitating event. Without optimal treatment, DKA remains a condition with appreciable, although largely preventable, morbidity and mortality. In this Primer, we discuss the epidemiology, pathogenesis, risk factors and diagnosis of DKA and provide practical recommendations for the management of DKA in adults and children

Interaction of plasminogen-related protein B with endothelial and smooth muscle cells in vitro

Plasminogen-related protein B (PRP-B) closely resembles the N-terminal plasminogen activation peptide, which is released from plasminogen during conversion to plasmin. We have previously demonstrated that the steady-state level of mRNA encoding PRP-B is increased within tumor tissues, and that recombinant PRP-B antagonizes neoplastic growth when administered systemically to mice harboring tumors, but no insights into the cell targets of PRP-B have been presented. Employing serum-free medium optimized for culturing human endothelial or smooth muscle cells, we show that recombinant PRP-B inhibits basic fibroblast growth factor-dependent cell migration for both cell types, as well as tube formation of endothelial cells. Comparison with the angiogenesis inhibitors angiostatin and endostatin revealed similar results. Recombinant PRP-B is effective in promoting cell attachment of endothelial and smooth muscle cells, and antibody interference experiments reveal that the interaction of recombinant PRP-B with endothelial cells is mediated at least in part by α v-containing integrins. Inhibition of angiogenesis in vivo by PRP-B was demonstrated in the chicken chorioallantoic membrane assay. PRP-B and other antiangiogenic molecules may elicit metabolic perturbations in endothelial cells as well as perivascular mesenchymal cells such as smooth muscle cells and pericytes

Alendronate Inhibits Growth of High-grade Chondrosarcoma Cells

Background: Conventional chemotherapy is ineffective for high-grade chondrosarcomas, highlighting the need for improved chemotherapies. Various clinical trials have been initiated using antiapoptotic agents and perifosine, and are truly in the experimental phases. Chondrosarcoma is still therefore considered a surgical disease despite its aggressive features of recurring locally and spreading to the lungs. Bisphosphonates inhibit growth of various cell types, including cancer cells and perhaps chondrosarcoma. Materials and Methods: The effect of different concentrations of alendronate on cell proliferation, migration, apoptosis and cytoskeleton reorganization as well as on the regulation of intracellular protein expression were analyzed for the high-grade chondrosarcoma cell line CS-1. Mevalonate pathway intermediates were used in some experiments to assess mechanistic aspects. Results: Alendronate decreased cell viability of CS-1 by inhibiting cell proliferation and cell migration. Alendronate-induced loss of cell viability led to a sequence of events including apoptosis and cytoskeletal rearrangements. Moreover, changes in the expression levels of various proteins involved in cell proliferation, migration, cell cycle, apoptosis and cytoskeleton reorganization were demonstrated. Conclusion: Alendronate exerts antiproliferative effects by perturbing various signaling pathways in CS-1 cells. These findings may lead to new treatment options for high-grade chondrosarcoma

Antiangiogenesis treatment combined with chemotherapy produces chondrosarcoma necrosis

A combination therapy protocol using a marine chemotherapeutic and an antiangiogenic molecule was tested in a mouse tumor xenograft model for the ability to curtail the growth of a human chondrosarcoma (CHSA). Ecteinascidin-743 (ET-743), a marine-derived chemotherapeutic, was effective at slowing the growth of a primary CHSA. Plasminogen-related protein B, which antagonizes various endothelial cell activities, also elicited a significant inhibition of neoplastic growth, albeit with reduced effectiveness. The combination of the two agents resulted in only a modest further repression of tumor growth over that associated with ET-743 treatment alone, as measured by tumor volume (82% versus 76% inhibition, respectively). However, analysis of the extent of tumor necrosis and vascularization of the tumor revealed that the coadministration of the two compounds was clearly more effective, eliciting a 2.5-fold increase in tumor necrosis relative to single-agent treatment. The combination therapy also was most effective at antagonizing tumor-associated microvessel formation, as assessed by CD31 immunostaining, suggesting that combination therapy may hold promise for treating CHSA. Tumor necrosis produced by combination therapy of ET-743 and recombinant plasminogen-related protein B was also significantly greater than that produced by conventional doxorubicin treatment, further corroborating the efficacy of combination therapy

Homologous plasminogen N-terminal and plasminogen-related gene A and B peptides - Characterization of cDNAs and recombinant fusion proteins

The cDNA corresponding to exons 2-4 of the processed human plasminogen (Pgn) gene, encoding the N-terminal peptide domain (NTP), has been cloned, expressed in Escherichia coli as a recombinant protein (r-NTP) containing a hexahistidine tag, and refolded to the native structure that contains two internal cystine bridges. RNA expression of the two Pgn-related genes, PRG A and PRG B, that potentially encode 9-kDa polypeptides having extensive similarity to the NTP has been investigated. Using RNA-based PCR with liver RNA as template,we demonstrate that PRG A encodes a detectable mRNA species. PRG A and PRG B have been found to be transcribed in the liver and yield virtually identical mRNAs. Neither of the PRGs are expressed in a variety of other normal tissues, as determined by Northern blot analysis. Factor-Xa digestion of the tagged r-NTP yields cleavage products which indicates that the expressed r-NTP domain of Pgn is endowed with a flexible conformation. Recombinant PRG B protein (r-PRG B) fused to a hexahistidine tag was purified and analyzed for structural integrity. Preliminary H-1-NMR spectroscopic data for r-NTP and r-PRG B indicate relatively fast amide H-1-H-2 exchange in (H2O)-H-2 and close conformational characteristics for the two homologous polypeptides. Far ultraviolet-CD spectra for r-NTP and r-PRG B at pH 7.0 indicate similar defined secondary structure content for both domains, with 13-17% alpha-helix and 24-27% antiparallel beta-sheet. The fact that two transcriptionally active genes encode almost identical polypeptides supports the hypothesis that the Pgn NTP, together with the putative polypeptides encoded by the PRGs, may serve an important function, such as controlling the conformation of Pgn and thus its susceptibility to tissue activators

Nuclear Magnetic Resonance Spectral Assignments of α‑1,4-Galactosyltransferase LgtC from <i>Neisseria meningitidis</i>: Substrate Binding and Multiple Conformational States

Lipopolysaccharide α-1,4-galactosyltransferase C (LgtC) from <i>Neisseria meningitidis</i> is responsible for a key step in lipooligosaccharide biosynthesis involving the transfer of α-galactose from the sugar donor UDP-galactose to a terminal acceptor lactose. Crystal structures of the complexes of LgtC with Mn²⁺ and the sugar donor analogue UDP-2-deoxy-2-fluorogalactose in the absence and presence of the sugar acceptor analogue 4′-deoxylactose provided key insights into the galactosyl-transfer mechanism. Combined with kinetic analyses, the enzymatic mechanism of LgtC appears to involve a “front-side attack” S_N<i>i</i>-like mechanism with a short-lived oxocarbenium–phosphate ion pair intermediate. As a prerequisite for investigating the required roles of structural dynamics in this catalytic mechanism by nuclear magnetic resonance techniques, the transverse relaxation-optimized amide ¹⁵N heteronuclear single-quantum correlation and methyl ¹³C heteronuclear multiple-quantum correlation spectra of LgtC in its apo, substrate analogue, and product complexes were partially assigned. This was accomplished using a suite of complementary spectroscopic approaches, combined with selective isotopic labeling and mutagenesis of all the isoleucine residues in the protein. Only ∼70% of the amide signals could be detected, whereas more than the expected number of methyl signals were observed, indicating that LgtC adopts multiple interconverting conformational states. Chemical shift perturbation mapping provided insights into substrate and product binding, including the demonstration that the sugar donor analogue (UDP-2FGal) associates with LgtC only in the presence of a metal ion (Mg²⁺). These spectral assignments provide the foundation for detailed studies of the conformational dynamics of LgtC