The relation of oxidative stress and apoptosis to histopathologic alterations in the lungs as a result of global cerebral ischemia

ABSTRACT

Heart attack and oxygen deficiency may cause necrosis in the brain and other tissues. We investigated the histopathological effects of nitric oxide (NO) on ischemia/reperfusion in lung and hippocampus using a rat brain bilateral occlusion ischemia model. Male rats were assigned to sham (SH), ischemic preconditioning (PC), global ischemia (GI) and ischemic reperfusion (IR) groups. Before ischemia was induced, blood was drawn to induce hypovolemic hypotension and for blood gas testing. After sacrifice, samples of hippocampus were harvested. Sections were examined using hematoxylin and eosin (H & E) staining and immunostaining using primary antibodies for GFAP, S100β, iNOS, eNOS and the TUNEL method. Following ischemia, we found evidence of gliosis induced oxidative stress and apoptosis in the hippocampus. No significant differences were detected between the SH and PC groups. In the GI and IR groups, apoptosis and necrosis were observed in the hippocampus. Lung sections were stained with H & E and Masson’s trichrome (MT) and immunostained for iNOS and eNOS. The TUNEL method was used to detect apoptosis. Interstitial edema, vascular congestion, intra-alveolar hemorrhage, perivascular edema, neutrophil infiltration and disruption of alveoli were observed after global ischemia and ischemic reperfusion. Inflammatory cells were detected in the connective tissue. The IR and GI groups exhibited significantly more apoptotic cells than the SH or PC groups. Free radicals, such as nitric oxide (NO), that appear following ischemia and reperfusion in the brain may also injure the lungs. Increased NO in both lung and brain tissue suggests that apoptosis in these organs can be induced by reactive nitrogen species.     

In vitro induction of neoantigen-specific T cells in myelodysplastic syndrome,a disease with low mutational burden

Therapies that utilize immune checkpoint inhibition work by leveraging mutation-derived neoantigens and have shown greater clinical efficacy in tumors with higher mutational burden. Whether tumors with a low mutational burden are susceptible to neoantigen-targeted therapy has not been fully addressed. To examine the feasibility of neoantigen-specific adoptive T-cell therapy, the authors studied the T-cell response against somatic variants in five patients with myelodysplastic syndrome (MDS), a malignancy with a very low tumor mutational burden. DNA and RNA from tumor (CD34⁺) and normal (CD3⁺) cells isolated from the patients’ blood were sequenced to predict patient-specific MDS neopeptides. Neopeptides representing the somatic variants were used to induce and expand autologous T cells ex vivo, and these were systematically tested in killing assays to determine the proportion of neopeptides yielding neoantigen-specific T cells. The authors identified a total of 32 somatic variants (four to eight per patient) and found that 21 (66%) induced a peptide-specific T-cell response and 19 (59%) induced a T-cell response capable of killing autologous tumor cells. Of the 32 somatic variants, 11 (34%) induced a CD4⁺ response and 11 (34%) induced a CD8⁺ response that killed the tumor. These results indicate that in vitro induction of neoantigen-specific T cells is feasible for tumors with very low mutational burden and that this approach warrants investigation as a therapeutic option for such patients.     

Facile synthesis and characterization of novel pyrazole-sulfonamides and their inhibition effects on human carbonic anhydrase isoenzymes

In the current study, a series of pyrazole-sulfonamide derivatives (2–14) were synthesized, characterized, and the inhibition effects of the derivatives on human carbonic anhydrases (hCA I and hCA II) were investigated as in vitro. Structures of these sulfonamides were confirmed by FT-IR, ¹H NMR, ¹³C NMR and LC–MS analysis. ¹H NMR and ¹³C NMR revealed the tautomeric structures. hCA I and hCA II isozymes were purified from human erythrocytes and inhibitory effects of newly synthesized sulfonamides on esterase activities of these isoenzymes have been studied. The K_i values of compounds were 0.062–1.278 μM for hCA I and 0.012–0.379 μM for hCA II. The inhibition effects of 7 for hCA I and 4 for hCA II isozymes were almost in nanomolar concentration range.     

Effects of Thymus kotschyanus var. glabrescens Boiss. extract on mitomycin-C induced chromosomal aberrations and sister chromatid exchanges in human lymphocytes

In this investigation, clastogenic effects of Thymus kotschyanus var. glabrescens Boiss. extract (TE) and anticlastogenic effects of this extract against Mitomycin C (MMC) induced chromosome damage have been evaluated in human peripheral blood lymphocytes in vitro. Two series of experiments were conducted. In the first, only 10⁻⁵, 10⁻⁴, 10⁻³ and 10⁻² μl ml⁻¹ concentrations of TE were used for 48 h to detect potential clastogenicity. In the second, MMC (0.38 μg ml⁻¹) plus 10⁻⁵, 10⁻⁴, 10⁻³ and 10⁻² μl ml⁻¹ concentrations of TE were used for 48 h to determine anticlastogenic effects. TE did not increase sister chromatid exchanges (SCEs) (except 10⁻² μl ml concentration) and chromosome aberrations (CAs) significantly compared with negative and solvent controls. However, it decreased the frequency of MMC induced chromosome aberrations. Decreasing was significant at 10⁻⁴, 10⁻³ and 10⁻² μl ml⁻¹ concentrations. On the other hand, TE significantly increased MMC-induced SCEs for all treatment groups compared with positive control.     

On the production,elemental composition (C,N, P) and distribution of photosynthetic organic matter in the Southern Black Sea

Chemical oceanographic understanding of the southernBlack Sea has been improved by recent measurements ofthe optical transparency, phytoplankton biomass (interms of chlorophyll-a and particulate organic matter)and primary productivity. During the spring-autmunperiod of 1995–1996, light generally penetrated onlyinto the upper 15–40 m, with an attenuation coefficientvarying between 0.125 and 0.350 m^2122;1. The averagechlorophyll-a (Chl-a) concentrations for the euphoticzone ranged from 0.1 to 1.5 μg l^2122;1. Coherentsub-surface Chl-a maxima were formed near the base ofthe euphotic zone only in summer. Production rate variedbetween 247 and 1925 in the spring and between 405 and687 mgC m^2122;2 d^2122;1 in the summer-autumn period.The average POM concentrations in the euphotic zonevaried regionally and seasonally between 3.8 and28.6 μm for POC, 0.5 and 3.1 μm for PON and0.02 and 0.1 μm for PP. Atomic ratios of C/N, C/Pand N/P, derived from the regressions of POM data,ranged between 7.5 and 9.6, 109 and 165, and 11.2 and16.6, respectively. In the suboxic/anoxic interface,the elemental ratios change substantially due to anaccumulation of PP cohering to Fe and Mn oxides. Thechemocline boundaries and the distinct chemicalfeatures of the oxic/anoxic transition layer (the so-called suboxic zone) are all located at specificdensity surfaces; however, they exhibit remarkablespatial and temporal variations both in their positionand in their magnitude, which permit the definition of long-term changes in the biochemical properties of theBlack Sea upper layer. This revised version was published online in July 2006 with corrections to the Cover Date.     

Free energy simulations of ligand binding to the aspartate transporter Glt(Ph)

Glutamate/Aspartate transporters cotransport three Na⁺ and one H⁺ ions with the substrate and countertransport one K⁺ ion. The binding sites for the substrate and two Na⁺ ions have been observed in the crystal structure of the archeal homolog Glt_Ph, while the binding site for the third Na⁺ ion has been proposed from computational studies and confirmed by experiments. Here we perform detailed free energy simulations of Glt_Ph, giving a comprehensive characterization of the substrate and ion binding sites, and calculating their binding free energies in various configurations. Our results show unequivocally that the substrate binds after the binding of two Na⁺ ions. They also shed light into Asp/Glu selectivity of Glt_Ph, which is not observed in eukaryotic glutamate transporters.     

TRPM2 Channel Membrane Currents in Primary Rat Megakaryocytes Were Activated by the Agonist ADP-Ribose but Not Oxidative Stress

Melastatin-like transient receptor potential 2 (TRPM2) channel activation/inhibition mechanisms in response to ADP-ribose (ADPR), oxidative stress, flufenamic acid (FFA) and 2-aminoethoxydiphenyl borate (2-APB) are not clear. We tested the effects of FFA and 2-APB on ADPR-induced TRPM2 cation channel currents in rat native bone marrow megakaryocytes. Megakaryocyte cells were freshly isolated from rat bone marrow and studied with the conventional whole-cell patch-clamp technique. Extracellular H₂O₂, FFA and 2-APB were added through the patch chamber, while intracellular ADPR was applied through the pipette. Nonselective cation currents were consistently induced by ADPR but not H₂O₂. Current density of ADPR in the cells was significantly (P < 0.001) higher than in control. The time courses of ADPR effects in the megakaryocytes were characterized by a delay of 2.24 ± 0.73. The ADPR-induced Ca²⁺ gate was not blocked by either the IP₃ receptor inhibitor 2-APB or the PLC inhibitor FFA. In conclusion, TRPM2 channels were constitutively activated by intracellular ADPR, although the channel currents in rat native megakaryocytes were not affected by extracellular H₂O₂, 2-APB or FFA. Activation of TRPM2 channels in megakaryocytes seems to be intracellular and ADPR-dependent.     

Effects of Nutrient Level on Maternal Choice and Siring Success in <Emphasis Type="Italic">Cucumis sativus</Emphasis> (Cucurbitaceae)

Plants have evolved many mechanisms to increase the chance of gene dispersal mainly through pollen and environmental factors play an important role. Understanding the mechanism behind gene dispersal is therefore crucial in the correct evaluation of the use of genetically modified crops for cultivation. In this paper we address the question of weather nutrient availability for the female affects the outcome of pollen competition between two pollen donor cultivars of Cucumis sativus. We do this by carrying out controlled crosses of female plants grown at three different nutrient levels. We separated the effect of a specific donor from the effect of pollen tube growth rate by using reversed crosses of fast and slow pollen. Our results show that female effects on siring ability vary with nutrient level. Pollen with a high pollen tube growth rate was more successful when nutrient availability for the female was high. This could be the result of selection on the female to adjust preference according to environmental circumstances. Pollen tube growth rate was measured under nutrient rich circumstances, thus high performers possessed traits adapted to a nutrient rich situation. Due to trade-off effects, these traits might not be advantageous in poor environments. Instead, individuals adapted to low nutrient circumstances will have a higher pollen tube growth rate. If siring ability varies with the environment of the recipient plant, this means that assessments of gene flow must account for this variation and include both pollen donors and recipient plants subjected to a range of environmental circumstances. In risk assessments of transgenic plants, plants are often kept under experimental, homogenous conditions. If our results also apply to other species, estimates of gene flow under constant conditions may be misleading. Selection on siring ability and female preference have fundamental effects on gene flow and need to be considered in risk assessments of transgenic plants.Co-ordinating editor: I. Olivieri