Metal complexes of antiinflammatory drugs. Part VII: Salsalate complex of copper(II)

The preparation and properties of the Cu(II) complex Cu(SAS)2.H2O are reported for the antiinflammatory drug Salsalate (SAS). The diffuse reflectance spectra and magnetic moments are consistent with a dinuclear structure as found for [Cu(aspirinate)2(H2O)]2. The Cu(II) complex exhibits an increased superoxide dismutase activity compared with the parent drug molecule in the nitroblue tetrazolium assay.     

Acquisition of the heat-shock response and thermotolerance during early development of Xenopus laevis

The ability to synthesize a 68,000- to 70,000-Da protein (hsp) in heat-shocked early Xenopus laevis embryos is dependent on the stage of development. Whereas late blastula and later stage embryos synthesize hsp68-70 after heat shock, cleavage stages are incompetent with respect to hsp synthesis. In vitro translation experiments and RNA blot analyses demonstrate that enhanced synthesis of hsp68-70 is associated with an accumulation of hsp68-70 mRNA. Examination of the effect of heat shock on preexisting actin mRNA reveals that heat shock promotes a reduction in the levels of actin mRNA in cleavage embryos but has no discernible effect on actin mRNA levels in neurula embryos. Finally, the acquisition of the heat-shock response (i.e., synthesis of hsp68-70 and accumulation of hsp70 mRNA) during early Xenopus development is correlated with the acquisition of thermotolerance.     

Two classes of continuous cell lines established from Syrian hamster 9 day gestation embryos: Preneoplastic cells and progenitor cells

Summary Primary cultures of 9-d-gestation Syrian hamster embryo (E9) cells are distinct from primary cultures of later gestational age in terms of their growth and differentiation. First, primary E9 cell cultures express multiple mesenchymal differentiation lineages (e.g., adipocyte, myoblast) only rarely seen in cultures of 13-d-gestation fetal (F13) cells. Second, although most primary E9 cultures have a limited in vitro proliferative life span and exhibit cellular senescence similar to primary cultures of F13 cells, E9 cultures seem to have higher frequency of escape from senescence and conversion to continuous cell lines compared to F13 cells. Moreover, this frequency can be further increased 4- to 5-fold by continuous exposure of the E9 cells to tumor promoters or epidermal growth factor. Eleven continuous cell lines have been isolated from unreated, promoter-treated, or epidermal growth factor-treated primary E9 cultures. Seven of these are neoplastic or preneoplastic. However, the remaining four do not show any evidence of being in neoplastic progression and three of these continue to express the same differentiated phenotype observed in ther parental primary cell cultures. These studies were supported in part by grants from the National Institutes of Health (AG 01998), Bethesda, MD, and the U.S. Department of Energy (DE-A-C02-76-EVO-3280), Washington, DC.     

Ophiobolin A induces paraptosis-like cell death in human glioblastoma cells by decreasing BKCa channel activity

Glioblastoma multiforme (GBM) is the most lethal and common malignant human brain tumor. The intrinsic resistance of highly invasive GBM cells to radiation- and chemotherapy-induced apoptosis accounts for the generally dismal treatment outcomes. This study investigated ophiobolin A (OP-A), a fungal metabolite from Bipolaris species, for its promising anticancer activity against human GBM cells exhibiting varying degrees of resistance to proapoptotic stimuli. We found that OP-A induced marked changes in the dynamic organization of the F-actin cytoskeleton, and inhibited the proliferation and migration of GBM cells, likely by inhibiting big conductance Ca²⁺-activated K⁺ channel (BKCa) channel activity. Moreover, our results indicated that OP-A induced paraptosis-like cell death in GBM cells, which correlated with the vacuolization, possibly brought about by the swelling and fusion of mitochondria and/or the endoplasmic reticulum (ER). In addition, the OP-A-induced cell death did not involve the activation of caspases. We also showed that the expression of BKCa channels colocalized with these two organelles (mitochondria and ER) was affected in this programmed cell death pathway. Thus, this study reveals a novel mechanism of action associated with the anticancer effects of OP-A, which involves the induction of paraptosis through the disruption of internal potassium ion homeostasis. Our findings offer a promising therapeutic strategy to overcome the intrinsic resistance of GBM cells to proapoptotic stimuli.     

Photolithographic synthesis of high-density oligonucleotide probe arrays

High-density DNA probe arrays provide a massively parallel approach to nucleic acid sequence analysis that is transforming gene-based biomedical research and diagnostics. Light-directed combinatorial oligonucleotide synthesis has enabled the large-scale production of GeneChip probe arrays which contain several hundred of thousand oligonucleotide sequences on glass "chips" about one cm2 in size. Due to their very high information content, GeneChip probe arrays are finding widespread use in the hybridization-based detection and analysis of mutations and polymorphisms ("genotyping"), and in a wide range of gene expression studies. The manufacturing process integrates solid-phase photochemical oligonucleotide synthesis with lithographic techniques adapted from the microelectronics industry. The present-generation methodology employs MeNPOC photo-activatable nucleoside monomers with proximity photolithography, and is currently capable of printing individual 10 microns 2 probe features at a density of 10(6) probes/cm2.     

Functional constraints on nest characteristics of pebble mounds of breeding male hornyhead chub Nocomis biguttatus

Breeding male hornyhead chub Nocomis biguttatus constructed nests in areas with relatively high but less than maximum flow rate and greater than average water depth. Nests comprised c. 3000 pebbles for a total mass of 11 kg. Males selected pebbles of smaller diameter but higher density than pebbles in the immediate vicinity. Thus, nests balanced the risk of mound erosion and energetic cost of nest construction with the benefits of protection from egg predators and a stable internal flow rate for oxygenation. These data help establish environmental management goals for the conservation of N. biguttatus and the lotic ecosystems dependent upon them.     

The effects of pH and the iron redox state on iron uptake in the intestine of a marine teleost fish, gulf toadfish (Opsanus beta)

In the marine teleost intestine the secretion of bicarbonate increases pH of the lumen (pH 8.4 -9.0) and importantly reduces Ca2+ and Mg2+ concentrations by the formation of insoluble divalent ion carbonates. The alkaline intestinal environment could potentially also cause essential metal carbonate formation reducing bioavailability. Iron accumulation was assessed in the Gulf toadfish (Opsanus beta) gut by mounting intestine segments in modified Ussing chambers fitted to a pH-stat titration system. This system titrates to maintain lumen pH constant and in the process prevents bicarbonate accumulation. The luminal saline pH was clamped to pH 5.5 or 7.0 to investigate the effect of proton concentrations on iron uptake. In addition, redox state was altered (gassing with N2, addition of dithiothreitol (DTT) and ascorbate) to evaluate Fe3+ versus Fe2+ uptake, enabling us to compare a marine teleost intestine model for iron uptake to the mammalian system for non-haem bound iron uptake that occurs via a ferrous/proton (Fe2+/H+) symporter called Divalent Metal Transporter 1 (DMT1). None of the redox altering strategies affected iron (Fe3+ or Fe2+) binding to mucus, but the addition of ascorbate resulted in a 4.6-fold increase in epithelium iron accumulation. This indicates that mucus iron binding is irrespective of valency and suggests that ferrous iron is preferentially transported across the apical surface. Altering luminal saline pH from 7.0 to 5.5 did not affect ferric or ferrous iron uptake, suggesting that if iron is entering via DMT1 in marine fish intestine this transporter works efficiently under circumneutral conditions.