Diabetic endothelial dysfunction: the role of poly(ADP-ribose) polymerase activation

Diabetic patients frequently suffer from retinopathy, nephropathy, neuropathy and accelerated atherosclerosis. The loss of endothelial function precedes these vascular alterations. Here we report that activation of poly(ADP-ribose) polymerase (PARP) is an important factor in the pathogenesis of endothelial dysfunction in diabetes. Destruction of islet cells with streptozotocin in mice induced hyperglycemia, intravascular oxidant production, DNA strand breakage, PARP activation and a selective loss of endothelium-dependent vasodilation. Treatment with a novel potent PARP inhibitor, starting after the time of islet destruction, maintained normal vascular responsiveness, despite the persistence of severe hyperglycemia. Endothelial cells incubated in high glucose exhibited production of reactive nitrogen and oxygen species, consequent single-strand DNA breakage, PARP activation and associated metabolic and functional impairment. Basal and high-glucose-induced nuclear factor-kappaB activation were suppressed in the PARP-deficient cells. Our results indicate that PARP may be a novel drug target for the therapy of diabetic endothelial dysfunction.     

Characterization of rhodamine conjugated Agiotensin II peptide: synthesis,analysis and receptor binding and internalization

The results in this study show that the rhodamine fluorophore can be specifically conjugated to Angiotensin II at Lys3 residue (substituted for a Val) without altering the biological activity of the parent compound. The conjugated peptide was characterized using HPLC, mass spectrometry, and N-terminal sequencing. The rhodamine-Angiotensin II binds effectively to AT1 receptor and gets internalized in clathrin coated vesicles by endocytosis. These results clearly suggest the usefulness of fluorophore-conjugated peptides in studies such as, ligand-receptor binding, and ligand-receptor complex internalization, for drug delivery using cell receptors and as an alternative to peptide hormone radioimmunoassays.     

Optical quantitative pathology of cervical intraepithelial neoplasia in human tissues using spatial frequency analysis

An optical quantitative histological method in human tissues using spatial frequencies is demonstrated. Optical spatial frequency spectra from different stages of human Cervical Intraepithelial Neoplasia (CIN) tissue are evaluated as a potential quantitative pathological tool. The degree of randomness of tissue structures from normal to different stages of CIN tissue can be recognized by spatial frequency analysis. The standard deviation, σ of human normal and CIN tissue, is obtained by assuming the spatial frequency spectra as a Gaussian distribution. A support vector machine classifier (SVM) is trained in the subspace of σ. Twenty‐eight normal and CIN samples of varying grades are examined and compared with current diagnostic outcomes. Our results suggest that an excellent accuracy for diagnostic purposes can be achieved. This approach offers a simple, efficient and objective way to supplement histopathology in recognizing alterations from normal to different stages of cervical pre‐cancer, which are reflected by spatial information contained within the aperiodic and random structures of the different types of tissue. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Measurement and comparison of head scatter factor for 7 MV unflattened (FFF) and 6 MV flattened photon beam using indigenously designed columnar mini phantom

Aim

To measure and compare the head scatter factor for 7 MV unflattened and 6 MV flattened photon beam using a home-made designed mini phantom.

Background

The head scatter factor (Sc) is one of the important parameters for MU calculation. There are multiple factors that influence the Sc values, like accelerator head, flattening filter, primary and secondary collimators.

Materials and methods

A columnar mini phantom was designed as recommended by AAPM Task Group 74 with high and low atomic number material for measurement of head scatter factors at 10 cm and d_max dose water equivalent thickness.

Results

The Sc values measured with high-Z are higher than the low-Z mini phantoms observed for both 6MV-FB and 7MV-UFB photon energies. Sc values of 7MV-UFB photon beams were smaller than those of the 6MV-FB photon beams (0.6–2.2% (Primus), 0.2–1.4% (Artiste) and 0.6–3.7% (Clinac iX (2300CD))) for field sizes ranging from 10 cm × 10 cm to 40 cm × 40 cm. The SSD had no influence on head scatter for both flattened and unflattened beams. The presence of wedge filters influences the Sc values. The collimator exchange effects showed that the opening of the upper jaw increases Sc irrespective of FF and FFF.

Conclusions

There were significant differences in Sc values measured for 6MV-FB and unflattened 7MV-UFB photon beams over the range of field sizes from 10 cm × 10 cm to 40 cm × 04 cm. Different results were obtained for measurements performed with low-Z and high-Z mini phantoms.     

Activation of RAW 264.7 cells by Astraeus hygrometricus-derived heteroglucan through MAP kinase pathway

Mushroom-derived polysaccharides like β-glucan are being investigated for therapeutic properties for a long time, but their mode of action of immunomodulatory properties is not well established. In the present study, a heteroglucan from Astraeus hygrometricus designated as AE2 is investigated for its macrophage stimulatory properties using RAW 264.7 cell line. An augmentation of nitric oxide production is observed in the presence of AE2 in a dose-dependent manner due to up-regulation of iNOS (inducible NO synthase) expression; hence NF κB (nuclear factor κB) pathway is investigated. RAW 264.7 cells endured phosphorylation of Ikk (IκB kinase) and subsequently NF κB is translocated to the nucleus. Further, the PKC (protein kinase C) level of the cells enhanced significantly. We also found that AE2 could induce the phosphorylation of p38 MAPK (mitogen-activated protein kinase), ERK1/2 (extracellular-signal-regulated kinase 1/2), MEK (MAPK/ERK kinase) and JNK (c-Jun N-terminal kinase), whereas it failed to induce phosphorylation of JAK2 (Janus kinase 2) and STAT1. These results indicated that the macrophage activation by AE2 might be exerted, at least in part, via MAPKs (mitogen-activated protein kinases) pathway of signal transduction.     

Ontogenetic de novo copy number variations (CNVs) as a source of genetic individuality: studies on two families with MZD twins for schizophrenia

Genetic individuality is the foundation of personalized medicine, yet its determinants are currently poorly understood. One issue is the difference between monozygotic twins that are assumed identical and have been extensively used in genetic studies for decades. Here, we report genome-wide alterations in two nuclear families each with a pair of monozygotic twins discordant for schizophrenia evaluated by the Affymetrix 6.0 human SNP array. The data analysis includes characterization of copy number variations (CNVs) and single nucleotide polymorphism (SNPs). The results have identified genomic differences between twin pairs and a set of new provisional schizophrenia genes. Samples were found to have between 35 and 65 CNVs per individual. The majority of CNVs (~80%) represented gains. In addition, ~10% of the CNVs were de novo (not present in parents), of these, 30% arose during parental meiosis and 70% arose during developmental mitosis. We also observed SNPs in the twins that were absent from both parents. These constituted 0.12% of all SNPs seen in the twins. In 65% of cases these SNPs arose during meiosis compared to 35% during mitosis. The developmental mitotic origin of most CNVs that may lead to MZ twin discordance may also cause tissue differences within individuals during a single pregnancy and generate a high frequency of mosaics in the population. The results argue for enduring genome-wide changes during cellular transmission, often ignored in most genetic analyses.