Asymmetric addition of dimethylzinc to alkylidenmalonates mediated by phosphorous ligands: a new synthetic route to floral fragrances

Six new phosphite ligands were prepared and their efficiency as chiral ligands was investigated in the copper-catalyzed asymmetric conjugate addition of dimethylzinc to diethyl 3-phenylpropylidenmalonate (5), affording the addition product with ees up to 74%. Moreover, a simple and straightforward route to floral fragrances Phenoxanol, Citralis, and Nitrile Citralis in optically active form through the above cited reaction was proposed.     

Medium pH and nitrate concentration effects on accumulation of triacylglycerol in two members of the chlorophyta

Algal-derived biodiesel is of particular interest because of several factors including: the potential for a near-carbon-neutral life cycle, the prospective ability for algae to capture carbon dioxide generated from coal, and algae’s high per acre yield potential. Our group and others have shown that in nitrogen limitation, and for a single species of Chlorella, a rise in culture medium pH yields triacylglycerol (TAG) accumulation. To solidify and expand on these triggers, the influence and interaction of pH and nitrogen concentration on lipid production was further investigated on Chlorophyceae Scenedesmus sp. and Coelastrella sp. Growth was monitored optically and TAG accumulation was monitored by Nile red fluorescence and confirmed by gas chromatography. Both organisms grew in all treatments and TAG accumulation was observed by two distinct conditions: high pH and nitrogen limitation. The Scenedesmus sp. was shown to grow and produce lipids to a larger degree in alkaliphilic conditions (pH >9) and was used to further investigate the interplay between TAG accumulation from high pH and/or nitrate depletion. Results given here indicate that TAG accumulation per cell, monitored by Nile red fluorescence, correlates with pH at the time of nitrate depletion.     

Cytogenetic stability of chicken T-cell line transformed with Marek's disease virus: atomic force microscope, a new tool for investigation

The Marek's disease virus (MDV) integration may induce a novel organization of chromatin architecture with a modified genetic expression. In our opinion it is worthwhile trying to relate cytogenetic stability to functional modifications. Recently, atomic force microscopy technique was applied to study the structure of chromosomes at a nanoscale level. This high resolution allows to investigate the different structure of chromatin in order to study cytogenetic stability and chromosome aberrations due to MDV insertion. In this paper data are presented indicating a duplication [78,WZ,dup(1p)(p22-p23)] and a deletion [78,WZ cht del(3)(q2.10)] of Chromosomes 1 and 3 relatively. Relationships between GTG (G-bands by Trypsin using Giemsa) bands and the topography of chromosomes are also discussed, naming them Topographic Banding. The architecture of chromosomes observed by AFM can be related to the data obtained with classic banding techniques thus overcoming the optical resolution limits. The presence of chromatin bridges between sister chromatids at most of the heterochromatic regions is also evidenced. Besides, we present different studies of the longitudinal and transversal symmetry of the hetero and euchromatic regions to clearly demonstrate a different underlying architecture of these regions. It is indeed evident that the heterochromatic bands are more symmetrical than euchromatic bands.     

Distribution of CD4pos -, CD8pos – and Regulatory T Cells in the Upper and Lower Gastrointestinal Tract in Healthy Young Subjects

The gastrointestinal immune system is involved in the development of several autoimmune-mediated diseases, including inflammatory bowel disease, multiple sclerosis, and type 1 diabetes mellitus. Alterations in T-cell populations, especially regulatory T cells (Tregs), are often evident in patients suffering from these diseases. To be able to detect changes in T-cell populations in diseased tissue, it is crucial to investigate T-cell populations in healthy individuals, and to characterize their variation among different regions of the gastrointestinal (GI) tract. While limited data exist, quantitative data on biopsies systematically drawn from various regions of the GI tract are lacking, particularly in healthy young humans. In this report, we present the first systematic assessment of how T cells—including Tregs—are distributed in the gastrointestinal mucosa throughout the GI tract of healthy young humans by means of multi-parameter FACS analysis. Gastroduodenoscopy and colonoscopy were performed on 16 healthy volunteers aged between 18 and 32. Biopsies were drawn from seven GI regions, and were used to determine the frequencies of CD8⁺-, CD4⁺- and Tregs in the gastrointestinal mucosa by means of multi-parameter FACS analysis. Our data show that there is significant variation in the baseline T-cell landscape along the healthy human gastrointestinal tract, and that mucosal T-cell analyses from a single region should not be taken as representative of the entire gastrointestinal tract. We show that certain T-cell subsets in the gastrointestinal mucosa vary significantly among regions; most notably, that Tregs are enriched in the appendiceal orifice region and the ascending colon, and that CD8^pos T cells are enriched in the gastric mucosa.     

Liver Glycerol Permeability and Aquaporin-9 Are Dysregulated in a Murine Model of Non-Alcoholic Fatty Liver Disease

One form of liver steatosis, namely Non-Alcoholic Fatty Liver Disease (NAFLD), is a worrisome health problem worldwide characterized by intrahepatic triacylglycerol (TG) overaccumulation. NAFLD is a common feature of metabolic syndrome being often associated with obesity, dyslipidemia and diabetes and mostly closely linked to insulin resistance. The mechanism of NAFLD pathogenesis is object of intense investigation especially regarding complex systems ultimately resulting in excessive TG deposition in hepatocytes. However, scarce is the attention about the relevance of hepatic import of glycerol, the other primary source (as glycerol-3-phosphate) of increased TG in hepatocytes. Obese leptin-deficient (ob/ob) mice, an animal model of NAFLD, were used to evaluate the functional involvement of Aquaporin-9 (AQP9), the major pathway of liver glycerol entry, in hepatosteatosis. By RT-PCR and qPCR, the level of Aqp9 mRNA in the liver of starved obese mice was comparable with the corresponding control lean littermates. By immunoblotting, the AQP9 protein at the hepatocyte sinusoidal plasma membrane of obese mice was markedly lower (33%) than lean mice, a finding fully confirmed by immunohistochemistry. By stopped-flow light scattering, the liver glycerol permeability of ob/ob mice was significantly lower (53%) than lean mice, a finding consistent with both the observed down-regulation of AQP9 protein and increased level of plasma glycerol characterizing obese mice. In summary, our results suggest implication of AQP9 in liver steatosis. The reduction of hepatocyte AQP9 and, consequently, glycerol permeability might be a defensive mechanism to counteract further fat infiltration in liver parenchyma.     

ROS Production and NF-κB Activation Triggered by RAC1 Facilitate WNT-Driven Intestinal Stem Cell Proliferation and Colorectal Cancer Initiation

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Human Sarcoma Growth Is Sensitive to Small-Molecule Mediated AXIN Stabilization

Sarcomas are mesenchymal tumors showing high molecular heterogeneity, reflected at the histological level by the existence of more than fifty different subtypes. Genetic and epigenetic evidences link aberrant activation of the Wnt signaling to growth and progression of human sarcomas. This phenomenon, mainly accomplished by autocrine loop activity, is sustained by gene amplification, over-expression of Wnt ligands and co-receptors or epigenetic silencing of endogenous Wnt antagonists. We previously showed that pharmacological inhibition of Wnt signaling mediated by Axin stabilization produced in vitro and in vivo antitumor activity in glioblastoma tumors. Here, we report that targeting different sarcoma cell lines with the Wnt inhibitor/Axin stabilizer SEN461 produces a less transformed phenotype, as supported by modulation of anchorage-independent growth in vitro. At the molecular level, SEN461 treatment enhanced the stability of the scaffold protein Axin1, a key negative regulator of the Wnt signaling with tumor suppressor function, resulting in downstream effects coherent with inhibition of canonical Wnt signaling. Genetic phenocopy of small molecule Axin stabilization, through Axin1 over-expression, coherently resulted in strong impairment of soft-agar growth. Importantly, sarcoma growth inhibition through pharmacological Axin stabilization was also observed in a xenograft model in vivo in female CD-1 nude mice. Our findings suggest the usefulness of Wnt inhibitors with Axin stabilization activity as a potentialyl clinical relevant strategy for certain types of sarcomas.     

Predicting Progression of Alzheimer’s Disease Using Ordinal Regression

We propose a novel approach to predicting disease progression in Alzheimer’s disease (AD) – multivariate ordinal regression – which inherently models the ordered nature of brain atrophy spanning normal aging (CTL) to mild cognitive impairment (MCI) to AD. Ordinal regression provides probabilistic class predictions as well as a continuous index of disease progression – the ORCHID (Ordinal Regression Characteristic Index of Dementia) score. We applied ordinal regression to 1023 baseline structural MRI scans from two studies: the US-based Alzheimer’s Disease Neuroimaging Initiative (ADNI) and the European based AddNeuroMed program. Here, the acquired AddNeuroMed dataset was used as a completely independent test set for the ordinal regression model trained on the ADNI cohort providing an optimal assessment of model generalizability. Distinguishing CTL-like (CTL and stable MCI) from AD-like (MCI converters and AD) resulted in balanced accuracies of 82% (cross-validation) for ADNI and 79% (independent test set) for AddNeuroMed. For prediction of conversion from MCI to AD, balanced accuracies of 70% (AUC of 0.75) and 75% (AUC of 0.81) were achieved. The ORCHID score was computed for all subjects. We showed that this measure significantly correlated with MMSE at 12 months (ρ = –0.64, ADNI and ρ = –0.59, AddNeuroMed). Additionally, the ORCHID score can help fractionate subjects with unstable diagnoses (e.g. reverters and healthy controls who later progressed to MCI), moderately late converters (12–24 months) and late converters (24–36 months). A comparison with results in the literature and direct comparison with a binary classifier suggests that the performance of this framework is highly competitive.     

Postnatal Hyperoxia Exposure Differentially Affects Hepatocytes and Liver Haemopoietic Cells in Newborn Rats

Premature newborns are frequently exposed to hyperoxic conditions and experimental data indicate modulation of liver metabolism by hyperoxia in the first postnatal period. Conversely, nothing is known about possible modulation of growth factors and signaling molecules involved in other hyperoxic responses and no data are available about the effects of hyperoxia in postnatal liver haematopoiesis. The aim of the study was to analyse the effects of hyperoxia in the liver tissue (hepatocytes and haemopoietic cells) and to investigate possible changes in the expression of Vascular Endothelial Growth Factor (VEGF), Matrix Metalloproteinase 9 (MMP-9), Hypoxia-Inducible Factor-1α (HIF-1α), endothelial Nitric Oxide Synthase (eNOS), and Nuclear Factor-kB (NF-kB). Experimental design of the study involved exposure of newborn rats to room air (controls), 60% O₂ (moderate hyperoxia), or 95% O₂ (severe hyperoxia) for the first two postnatal weeks. Immunohistochemical and Western blot analyses were performed. Severe hyperoxia increased hepatocyte apoptosis and MMP-9 expression and decreased VEGF expression. Reduced content in reticular fibers was found in moderate and severe hyperoxia. Some other changes were specifically produced in hepatocytes by moderate hyperoxia, i.e., upregulation of HIF-1α and downregulation of eNOS and NF-kB. Postnatal severe hyperoxia exposure increased liver haemopoiesis and upregulated the expression of VEGF (both moderate and severe hyperoxia) and eNOS (severe hyperoxia) in haemopoietic cells. In conclusion, our study showed different effects of hyperoxia on hepatocytes and haemopoietic cells and differential involvement of the above factors. The involvement of VEGF and eNOS in the liver haemopoietic response to hyperoxia may be hypothesized.