Ras oncogene mediated induction of a 92 kDa metalloproteinase; strong correlation with the malignant phenotype

We have previously demonstrated that activated ras oncogenes can induce the metastatic phenotype and type IV collagenolytic activity in NIH/3T3 cells (Thorgeirsson et al. Mol. Cell. Biol. 5:259-262, 1985). The present study demonstrates ras-mediated induction of a 92 kDa metalloproteinase, which degrades gelatin and type IV collagen. Association of the 92 kDa proteinase expression with the malignant phenotype was also observed in human tumor cell lines. Our data indicate that the 92 kDa gelatin-collagen IV degrading metalloproteinase is an important participant in the proteolytic process involving tumor cell invasion and metastasis.     

Macromolecular syntheses and the course of cell cycle events in the chlorococcal algaScenedesmus quadricauda under nutrient starvation: Effect of nitrogen starvation

Daughter cells of the chlorococcal algaScenedesmus quadricauda incubated under photosynthesizing conditions in a nitrogen-free medium did not make any progress in the cell cycle. Photosynthetic starch formation continued for a period corresponding to a half of the cell cycle and then levelled off. Protein synthesis was very slow and it did not surpass double the initial amount. RNA content decayed from the start of treatment and approached about 2 pg/cell. When a synchronous population was deprived of nitrogen or of light in the middle of the cell cycle RNA synthesis stopped immediately or very soon afterwards and, in spite ofabundant intracellular nitrogen reserves, RNA content slowly declined. This degradation was much extensive in nitrogen starved cells where, eventually, the RNA content attained about half the starting value. In both experimental variants, DNA replications started at the same time as in control culture, but the final amount of DNA attained only half the control value. Protein synthesis stopped immediately in the dark. In the nitrogen-starved cells, it continued for several hours and protein content increased about 70 % of the amount present at the start of starvation. The number of daughter cells formed was proportional to the final protein content in the nitrogen-and light-deprived cells (corresponding division numbers were 6 and 4, respectively). Upon refeeding of daughter cells formed under nitrogen starvation, RNA synthesis started immediately, while protein synthesis displayed a lag of about 5 h. DNA replications were triggered at the time when the ratio of RNA to DNA content attained the same value as in the control culture.     

Development of cell surface saccharides on embryonic pancreatic cells

Using a battery of seven lectin-ferritin conjugates as probes for cell surface glycoconjugates, we have studied the pattern of plasmalemmal differentiation of cells in the embryonic rat pancreas from day 15 in utero to the early postpartum stage. Our results indicate that differentiation of plasmalemmal glycoconjugates on acinar, endocrine, and centroacinar cells is temporally correlated with development and is unique for each cell type, as indicated by lectin-ferritin binding. Specifically, (a) expression of adult cell surface saccharide phenotype can be detected on presumptive acinar cells as early as 15 d in utero, as indicated by soybean agglutinin binding, and precedes development of intracellular organelles characteristic of mature acinar cells; (b) maturation of the plasmalemma of acinar cells is reached after intracellular cytodifferentiation is completed, as indicated by appearance of Con A and fucoselectin binding sites only at day 19 of development; conversely, maturation of the endocrine cell plasmalemma is accompanied by "loss" (masking) of ricinus communis II agglutinin receptors; and (c) binding sites for fucose lectins and for soybean agglutinin are absent on endocrine and centroacinar cells at all stages examined. We conclude that acinar, centroacinar, and endocrine cells develop from a common progenitor cell(s) whose plasmalemmal carbohydrate composition resembles most closely that of the adult centroacinar cell. Finally, appearance of acinar lumina beginning at approximately 17 d in utero is accompanied by differenetiation of apical and basolateral plasmalemmal domains of epithelial cells, as indicated by enhanced binding of several lectin-ferritin conjugates to the apical plasmalemmal, a pattern that persists from this stage through adult life.     

Age-Specific Mortality During the 1918 Influenza Pandemic: Unravelling the Mystery of High Young Adult Mortality

The worldwide spread of a novel influenza A (H1N1) virus in 2009 showed that influenza remains a significant health threat, even for individuals in the prime of life. This paper focuses on the unusually high young adult mortality observed during the Spanish flu pandemic of 1918. Using historical records from Canada and the U.S., we report a peak of mortality at the exact age of 28 during the pandemic and argue that this increased mortality resulted from an early life exposure to influenza during the previous Russian flu pandemic of 1889–90. We posit that in specific instances, development of immunological memory to an influenza virus strain in early life may lead to a dysregulated immune response to antigenically novel strains encountered in later life, thereby increasing the risk of death. Exposure during critical periods of development could also create holes in the T cell repertoire and impair fetal maturation in general, thereby increasing mortality from infectious diseases later in life. Knowledge of the age-pattern of susceptibility to mortality from influenza could improve crisis management during future influenza pandemics.

“The war is over – and I must go” Egon Schiele, 1890–1918.

     

The cover of living and dead corals from airborne remote sensing

Trends in coral cover are widely used to indicate the health of coral reefs but are costly to obtain from field survey over large areas. In situ studies of reflected spectra at the coral surface show that living and recently dead colonies can be distinguished. Here, we investigate whether such spectral differences can be detected using an airborne remote sensing instrument. The Compact Airborne Spectrographic Imager (Itres Research Ltd, Canada) was flown in two configurations: 10 spectral bands with 1-m² pixels and 6 spectral bands with 0.25-m² pixels. First, we show that an instrument with 10 spectral bands possesses adequate spectral resolution to distinguish living Porites, living Pocillopora spp., partially dead Porites, recently dead Porites (total colony mortality within 6 months), old dead (>6 months) Porites, Halimeda spp., and coralline red algae when there is no water column to confuse spectra. All substrata were distinguished using fourth-order spectral derivatives around 538 nm and 562 nm. Then, at a shallow site (Tivaru) at Rangiroa Atoll, Tuamotu Archipelago (French Polynesia), we show that live and dead coral can be distinguished from the air to a depth of at least 4 m using first- and fourth-order spectral derivatives between 562–580 nm. However, partially dead and recently dead Porites colonies could not be distinguished from an airborne platform. Spectral differences among substrata are then exploited to predict the cover of reef substrata in ten 25-m² plots at nearby Motu Nuhi (max depth 8 m). The actual cover in these plots was determined in situ using quadrats with a 0.01-m² grid. Considerable disparity occurred between field and image-based measures of substrate cover within individual 25-m² quadrats. At this small scale, disparity, measured as the absolute difference in cover between field and remote-sensing methods, reached 25% in some substrata but was always less than 10% for living coral (99% of which consisted of Porites spp.). At the scale of the reef (all ten 25-m² quadrats), however, disparities in percent cover between imagery and field data were less than 10% for all substrata and extremely low for some classes (e.g. <3% for living Porites, recently dead Porites and Halimeda). The least accurately estimated substrata were sand and coralline red algae, which were overestimated by absolute values 7.9% and 6.6%, respectively. The precision of sampling was similar for field and remote-sensing methods: field methods required 19 plots to detect a 10% difference in coral cover among three reefs with a statistical power of 95%. Remote-sensing methods required 21 plots. However, it took 1 h to acquire imagery over 92,500 m² of reef, which represents 3,700 plots of 25 m² each, compared with 3 days to survey 10 such plots underwater. There were no significant differences in accuracy between 1-m² and 0.25-m² image resolutions, suggesting that the advantage of using smaller pixels is offset by reduced spectral information and an increase in noise (noise was observed to be 1.6–1.8 times greater in 0.25-m² pixels). We show that airborne remote sensing can be used to monitor coral and algal cover over large areas, providing that water is shallow and clear, and that brown fleshy macroalgae are scarce, that depth is known independently (e.g. from sonar survey).     

Specific protein domains mediate cooperative assembly of HuR oligomers on AU-rich mRNA-destabilizing sequences

The RNA-binding factor HuR is a ubiquitously expressed member of the Hu protein family that binds and stabilizes mRNAs containing AU-rich elements (AREs). Hu proteins share a common domain organization of two tandemly arrayed RNA recognition motifs (RRMs) near the N terminus, followed by a basic hinge domain and a third RRM near the C terminus. In this study, we engineered recombinant wild-type and mutant HuR proteins lacking affinity tags to characterize their ARE-binding properties. Using combinations of electrophoretic mobility shift and fluorescence anisotropy-based binding assays, we show that HuR can bind ARE substrates as small as 13 nucleotides with low nanomolar affinity, but forms cooperative oligomeric protein complexes on ARE substrates of at least 18 nucleotides in length. Analyses of deletion mutant proteins indicated that RRM3 does not contribute to high affinity recognition of ARE substrates, but is required for cooperative assembly of HuR oligomers on RNA. Finally, the hinge domain between RRM2 and RRM3 contributes significant binding energy to HuR.ARE complex formation in an ARE length-dependent manner. The hinge does not enhance RNA-binding activity by increased ion pair formation despite extensive positive charge within this region, and it does not thermodynamically stabilize protein folding. Together, the results define distinct roles for the HuR hinge and RRM3 domains in formation of cooperative HuR.ARE complexes in solution.     

Gene transfer to pre-hematopoietic and committed hematopoietic precursors in the early mouse Yolk Sac: a comparative study between <Emphasis Type="Italic">in situ</Emphasis> electroporation and retroviral transduction

Background  

Hematopoietic development in vertebrate embryos results from the sequential contribution of two pools of precursors independently generated. While intra-embryonic precursors harbour the features of hematopoietic stem cells (HSC), precursors formed earlier in the yolk sac (YS) display limited differentiation and self-renewal potentials. The mechanisms leading to the generation of the precursors in both sites are still largely unknown, as are the molecular basis underlying their different potential. A possible approach to assess the role of candidate genes is to transfer or modulate their expression/activity in both sites. We thus designed and compared transduction protocols to target either native extra-embryonic precursors, or hematopoietic precursors.     

European society of intensive care medicine study of therapeutic hypothermia (32-35°C) for intracranial pressure reduction after traumatic brain injury (the Eurotherm3235Trial)

Background

Severe malaria remains a major cause of global morbidity and mortality. Despite the use of potent anti-parasitic agents, the mortality rate in severe malaria remains high. Adjunctive therapies that target the underlying pathophysiology of severe malaria may further reduce morbidity and mortality. Endothelial activation plays a central role in the pathogenesis of severe malaria, of which angiopoietin-2 (Ang-2) has recently been shown to function as a key regulator. Nitric oxide (NO) is a major inhibitor of Ang-2 release from endothelium and has been shown to decrease endothelial inflammation and reduce the adhesion of parasitized erythrocytes. Low-flow inhaled nitric oxide (iNO) gas is a US FDA-approved treatment for hypoxic respiratory failure in neonates.

Methods/Design

This prospective, parallel arm, randomized, placebo-controlled, blinded clinical trial compares adjunctive continuous inhaled nitric oxide at 80 ppm to placebo (both arms receiving standard anti-malarial therapy), among Ugandan children aged 1-10 years of age with severe malaria. The primary endpoint is the longitudinal change in Ang-2, an objective and quantitative biomarker of malaria severity, which will be analysed using a mixed-effects linear model. Secondary endpoints include mortality, recovery time, parasite clearance and neurocognitive sequelae.

Discussion

Noteworthy aspects of this trial design include its efficient sample size supported by a computer simulation study to evaluate statistical power, meticulous attention to complex ethical issues in a cross-cultural setting, and innovative strategies for safety monitoring and blinding to treatment allocation in a resource-constrained setting in sub-Saharan Africa.

Trial Registration

ClinicalTrials.gov Identifier: NCT01255215