Activation of glucose transport during simulated ischemia in H9c2 cardiac myoblasts is mediated by protein kinase C isoforms

Glucose transport into cells may be regulated by a variety of conditions, including ischemia. We investigated whether some enzymes frequently involved in the metabolic adaptation to ischemia are also required for glucose transport activation. Ischemia was simulated by incubating during 3 h H9c2 cardiomyoblasts in a serum- and glucose-free medium in hypoxia. Under these conditions 2-deoxy-d-[2,6-³H]-glucose uptake was increased (57% above control levels, p < 0.0001) consistently with GLUT1 and GLUT4 translocation to sarcolemma. Tyrosine kinases inhibition via tyrphostin had no effect on glucose transport up-regulation induced by simulated ischemia. On the other hand, chelerythrine, a broad range inhibitor of protein kinase C isoforms, and rottlerin, an inhibitor of protein kinase C delta, completely prevented the stimulation of the transport rate. A lower activation of hexose uptake (19%, p < 0.001) followed also treatment with Gö6976, an inhibitor of conventional protein kinases C. Finally, PD98059-mediated inhibition of the phosphorylation of ERK 1/2, a downstream mitogen-activated protein kinase (MAPK), only partially reduced the activation of glucose transport induced by simulated ischemia (31%, p < 0.01), while SB203580, an inhibitor of p38 MAPK, did not exert any effect. These results indicate that stimulation of protein kinase C delta is strongly related to the up-regulation of glucose transport induced by simulated ischemia in cultured cardiomyoblasts and that conventional protein kinases C and ERK 1/2 are partially involved in the signalling pathways mediating this process.     

Lymphocyte DNA damage in patients with acute coronary syndrome and its relationship with severity of acute coronary syndrome

OBJECTIVE: The aim of this study was to investigate the association between lymphocyte DNA damage and acute coronary syndromes (ACS). METHODS: The study population contained 53 patients with ACS, 48 patients with stable angina and 35 voluntary healty subjects. DNA damage was assessed by alkaline comed assay in peripheral lymphocyte and plasma levels of total antioxidant capacity (TAC) were determined using a novel automated measurement method. RESULTS: In ACS patients, DNA damage was significantly higher than in patients with stable angina and control subjects (144+/-52 AU, 116+/-37, 68+/-34 AU; for three p<0.001, respectively). The TAC levels in patients with ACS were lower than the other groups (1.24+/-0.31 mmol Trolox equiv./l, 1.46+/-0.29 mmol Trolox equiv./l, p<0.05, respectively). DNA damage values in patients with acute miyocardial infarction were significantly higher than in patients with unstable angina (159.8+/-53.0 AU versus 131.8+/-48.4 AU; p<0.05, respectively). Lymphocyte DNA damage values in patients with ACS showed positive correlation with d-dimer (r=0.880, p<0.001) troponin I (r=538, p<0.001) and C-reactive protein (r=0.544, p<0.001) and negative correlation with TAC (r=-0.346, p=0.011). In multiple linear regression analysis, TAC (beta=-0.213, p=0.001) and d-dimer (beta=0.697, p<0.001) were independent predictors of DNA damage in patients with ACS. CONCLUSIONS:These findings indicate that lymphocyte DNA damage level increases in patients with ACS. Elevated DNA damage may be related with plaque instability and be useful for the identification of patients with acute coronary syndromes.     

Vaccine-induced tumor-specific immunity despite severe B-cell depletion in mantle cell lymphoma

The role of B cells in T-cell priming is unclear, and the effects of B-cell depletion on immune responses to cancer vaccines are unknown. Although results from some mouse models suggest that B cells may inhibit induction of T cell-dependent immunity by competing with antigen-presenting cells for antigens, skewing T helper response toward a T helper 2 profile and/or inducing T-cell tolerance, results from others suggest that B cells are necessary for priming as well as generation of T-cell memory. We assessed immune responses to a well-characterized idiotype vaccine in individuals with severe B-cell depletion but normal T cells after CD20-specific antibody-based chemotherapy of mantle cell lymphoma in first remission. Humoral antigen- and tumor-specific responses were detectable but delayed, and they correlated with peripheral blood B-cell recovery. In contrast, vigorous CD4(+) and CD8(+) antitumor type I T-cell cytokine responses were induced in most individuals in the absence of circulating B cells. Analysis of relapsing tumors showed no mutations or change in expression of target antigen to explain escape from therapy. These results show that severe B-cell depletion does not impair T-cell priming in humans. Based on these results, it is justifiable to administer vaccines in the setting of B-cell depletion; however, vaccine boosts after B-cell recovery may be necessary for optimal humoral responses.     

Cortical spreading depression modifies components of the inflammatory cascade

As more information becomes available regarding the role of inflammation following stroke, it is apparent that some inflammatory mediators are detrimental and others are beneficial to the progression of ischemic injury. Cortical spreading depression (CSD) is known to impart some degree of ischemic tolerance to the brain and to influence the expression of many genes. Many of the genes whose expression is altered by CSD are associated with inflammation, and it appears likely that modulation of the inflammatory response to ischemia by CSD contributes to ischemic tolerance. Understanding which inflammatory processes are influenced by CSD may lead to the identification of novel targets in the effort to develop an acute treatment for stroke.     

Cytotoxic properties of oligostilbenoids from the tree barks of Hopea dryobalanoides

A new modified stilbene dimer, diptoindonesin D (1), was isolated from the acetone extract of the tree bark of Hopea dryobalanoides, together with seven known compounds, parviflorol (2), (-)-balanocarpol (3), heimiol A (4), hopeafuran (5), (+)-alpha-viniferin (6), vaticanol B (7) and (-)-hopeaphenol (8). Cytotoxic properties of compounds 1-8 were evaluated against murine leukemia P-388 cells. Compound 8 was found to be the most active with IC50 of 5.7 microM.     

Genomic and morphological evidence converge to resolve the enigma of Strepsiptera

The phylogeny of insects, one of the most spectacular radiations of life on earth, has received considerable attention. However, the evolutionary roots of one intriguing group of insects, the twisted-wing parasites (Strepsiptera), remain unclear despite centuries of study and debate. Strepsiptera exhibit exceptional larval developmental features, consistent with a predicted step from direct (hemimetabolous) larval development to complete metamorphosis that could have set the stage for the spectacular radiation of metamorphic (holometabolous) insects. Here we report the sequencing of a Strepsiptera genome and show that the analysis of sequence-based genomic data (comprising more than 18 million nucleotides from nearly 4,500 genes obtained from a total of 13 insect genomes), along with genomic metacharacters, clarifies the phylogenetic origin of Strepsiptera and sheds light on the evolution of holometabolous insect development. Our results provide overwhelming support for Strepsiptera as the closest living relatives of beetles (Coleoptera). They demonstrate that the larval developmental features of Strepsiptera, reminiscent of those of hemimetabolous insects, are the result of convergence. Our analyses solve the long-standing enigma of the evolutionary roots of Strepsiptera and reveal that the holometabolous mode of insect development is more malleable than previously thought.     

Pregnancy and Infant Outcomes among HIV-Infected Women Taking Long-Term ART with and without Tenofovir in the DART Trial

Background

Few data have described long-term outcomes for infants born to HIV-infected African women taking antiretroviral therapy (ART) in pregnancy. This is particularly true for World Health Organization (WHO)–recommended tenofovir-containing first-line regimens, which are increasingly used and known to cause renal and bone toxicities; concerns have been raised about potential toxicity in babies due to in utero tenofovir exposure.

Methods and Findings

Pregnancy outcome and maternal/infant ART were collected in Ugandan/Zimbabwean HIV-infected women initiating ART during The Development of AntiRetroviral Therapy in Africa (DART) trial, which compared routine laboratory monitoring (CD4; toxicity) versus clinically driven monitoring. Women were followed 15 January 2003 to 28 September 2009. Infant feeding, clinical status, and biochemistry/haematology results were collected in a separate infant study. Effect of in utero ART exposure on infant growth was analysed using random effects models.382 pregnancies occurred in 302/1,867 (16%) women (4.4/100 woman-years [95% CI 4.0–4.9]). 226/390 (58%) outcomes were live-births, 27 (7%) stillbirths (≥22 wk), and 137 (35%) terminations/miscarriages (<22 wk). Of 226 live-births, seven (3%) infants died <2 wk from perinatal causes and there were seven (3%) congenital abnormalities, with no effect of in utero tenofovir exposure (p>0.4). Of 219 surviving infants, 182 (83%) enrolled in the follow-up study; median (interquartile range [IQR]) age at last visit was 25 (12–38) months. From mothers'' ART, 62/9/111 infants had no/20%–89%/≥90% in utero tenofovir exposure; most were also zidovudine/lamivudine exposed. All 172 infants tested were HIV-negative (ten untested). Only 73/182(40%) infants were breast-fed for median 94 (IQR 75–212) days. Overall, 14 infants died at median (IQR) age 9 (3–23) months, giving 5% 12-month mortality; six of 14 were HIV-uninfected; eight untested infants died of respiratory infection (three), sepsis (two), burns (one), measles (one), unknown (one). During follow-up, no bone fractures were reported to have occurred; 12/368 creatinines and seven out of 305 phosphates were grade one (16) or two (three) in 14 children with no effect of in utero tenofovir (p>0.1). There was no evidence that in utero tenofovir affected growth after 2 years (p = 0.38). Attained height- and weight for age were similar to general (HIV-uninfected) Ugandan populations. Study limitations included relatively small size and lack of randomisation to maternal ART regimens.

Conclusions

Overall 1-year 5% infant mortality was similar to the 2%–4% post-neonatal mortality observed in this region. No increase in congenital, renal, or growth abnormalities was observed with in utero tenofovir exposure. Although some infants died untested, absence of recorded HIV infection with combination ART in pregnancy is encouraging. Detailed safety of tenofovir for pre-exposure prophylaxis will need confirmation from longer term follow-up of larger numbers of exposed children.

Trial registration

www.controlled-trials.com ISRCTN13968779 Please see later in the article for the Editors'' Summary     

Latitude dependent arrhythmicity in the circadian oviposition rhythm of Drosophila ananassae

Latitude dependent arrhythmicity in the circadian rhythm of oviposition of Drosophila ananassae strains originating from 8.1°N to 32.7°N was studied by inbreeding them in cycles of 12 h of light at 20 lux and 12 h of darkness. The number of inbreeding generations required to initiate arrhythmicity in oviposition rhythm was dependent on the origin of latitude of the strain. The strains from the lower latitudes became arrhythmic after notably more numbers of generations than those from the higher latitudes. This might be attributed to the higher inherent degree of oviposition rhythmicity in the F₁ generation, and enhanced photic sensitivity of the circadian pacemaker mediating entrainment of oviposition rhythm of the strains from lower latitudes as compared to those from the higher latitudes.