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- Studies on the interaction of palmatine hydrochloride with bovine hemoglobin. [JOURNAL ARTICLE]
- Luminescence 2013 May 22.
The interaction between bovine hemoglobin (BHb) and palmatine hydrochloride (PMT) was investigated at different temperatures using multispectroscopy, as well as the effect of common metal ions (Ca(2+) , Mg(2+) , Zn(2+) , Cu(2+) , Fe(2+) , Fe(3+) , Co(2+) , Ni(2+) ) on the BHb-PMT system. Results showed that the quenching mechanism of PMT on BHb was a static process. The electrostatic force played an important role in the conjugation reaction between BHb and PMT. The order of magnitude of the binding constants (Ka ) was 10(4) , and the number of binding sites (n) in the binary system was ~ 1. The binding distance (r) was ~ 2.44 nm and the primary binding for PMT was located at β-37 tryptophan in the hydrophobic cavity of BHb. In addition, the Hill's coefficients were ~ 1. Synchronous and circular dichroism spectra revealed that the microenvironment and the conformation of BHb were changed during the binding reaction. Copyright © 2013 John Wiley & Sons, Ltd.
- Cryptochrome restores dampened circadian rhythms and promotes health span in aging Drosophila. [JOURNAL ARTICLE]
- Aging Cell 2013 May 20.
Circadian clocks generate daily rhythms in molecular, cellular, and physiological functions providing temporal dimension to organismal homeostasis. Recent evidence suggests two-way relationship between circadian clocks and aging. While disruption of the circadian clock leads to premature aging in animals, there is also age-related dampening of output rhythms such as sleep/wake cycles and hormonal fluctuations. Decay in the oscillations of several clock genes was recently reported in aged fruit flies, but mechanisms underlying these age-related changes are not understood. We report that the circadian light-sensitive protein CRYPTOCHROME (CRY), is significantly reduced at both mRNA and protein levels in heads of old Drosophila melanogaster. Restoration of CRY using the binary GAL4/UAS system in old flies significantly enhanced the mRNA oscillatory amplitude of several genes involved in the clock mechanism. Flies with CRY overexpressed in all clock cells maintained strong rest/activity rhythms in constant darkness late in life when rhythms were disrupted in most control flies. WE also observed a remarkable extension of health span in flies with elevated CRY. Conversely, CRY deficient mutants showed accelerated functional decline and accumulated greater oxidative damage. Interestingly, overexpression of CRY in central clock neurons alone was not sufficient to restore rest/activity rhythms or extend health span. Together, these data suggest novel anti-aging functions of CRY and indicate that peripheral clocks play an active role in delaying behavioral and physiological aging. This article is protected by copyright. All rights reserved.
- LabVIEW 2010 Computer Vision Platform Based Virtual Instrument and Its Application for Pitting Corrosion Study. [Journal Article]
- J Anal Methods Chem 2013.:193230.
A virtual instrumentation (VI) system called VI localized corrosion image analyzer (LCIA) based on LabVIEW 2010 was developed allowing rapid automatic and subjective error-free determination of the pits number on large sized corroded specimens. The VI LCIA controls synchronously the digital microscope image taking and its analysis, finally resulting in a map file containing the coordinates of the detected probable pits containing zones on the investigated specimen. The pits area, traverse length, and density are also determined by the VI using binary large objects (blobs) analysis. The resulting map file can be used further by a scanning vibrating electrode technique (SVET) system for rapid (one pass) "true/false" SVET check of the probable zones only passing through the pit's centers avoiding thus the entire specimen scan. A complete SVET scan over the already proved "true" zones could determine the corrosion rate in any of the zones.
- Investigating unmet health needs in primary health care services in a representative sample of the greek population. [Journal Article]
- Int J Environ Res Public Health 2013; 10(5):2017-27.
Unmet health care needs are determined as the difference between the services judged necessary and the services actually received, and stem from barriers related to accessibility, availability and acceptability. This study aims to examine the prevalence of unmet needs and to identify the socioeconomic and health status factors that are associated with unmet needs. A cross-sectional study was conducted in Greece in 2010 and involved data from 1,000 consenting subjects (>18 years old). Multiple binary logistic regression analysis was applied to investigate the predictors of unmet needs and to determine the relation between the socio-demographic characteristics and the accessibility, availability and acceptability barriers. Ninety nine participants (9.9%) reported unmet health needs during the 12 months prior to the research. The most frequently self-reported reasons were cost and lack of time. Youth, parenthood, physician consultations, and poor mental health increased the likelihood of unmet needs. Women were less likely to report accessibility and availability than acceptability barriers. Educational differences were evident and individuals with primary and secondary education were associated with significantly more accessibility and availability barriers compared with those with tertiary education. Unmet health needs pose a significant challenge to the health care system, especially given the difficult current financial situation in Greece. It is believed that unmet health needs will continue to increase, which will widen inequalities in health and health care access.
- Effect of proteins with different isoelectric point on the gene transfection efficiency mediated by stearic acid grafted chitosan oligosaccharide micelles. [JOURNAL ARTICLE]
- Mol Pharm 2013 May 16.
Stearic acid-grafted chitosan oligosaccharide (CS-SA) micelle has been demonstrated as an effective gene carrier in vitro and in vivo. Although being advantageous for DNA package, protection and excellent cellular internalization, CS-SA based delivery system may lead to difficulties in the dissociation of polymer/DNA complexes in intracells. In this research, bovine serum albumin (BSA) with different isoelectric point value (4.7, 6.0 and 9.3) was synthesized and incorporated into CS-SA based gene delivery system. CS-SA/DNA binary complexes and CS-SA/BSA/DNA ternary complexes were then prepared and characterized. The binding ability of the CS-SA vector with DNA was not affected by the incorporation of BSA. However referring to the transfection activity, BSA of different isoelectric point value (pI) had distinct influence on the CS-SA/BSA/DNA complexes. CS-SA/BSA (4.7)/DNA and CS-SA/BSA (6.0)/DNA complexes had better transfection efficiency than binary complexes, especially CS-SA/BSA (4.7)/DNA complexes showed the highest transfection efficiency. On the contrary, CS-SA/BSA (9.3)/DNA complexes had undesirable performances. Interestingly, the incorporation of BSA (4.7) in CS-SA/DNA complexes significantly enhanced the dissociation of polymer/DNA complexes and improved the release of DNA intracellular without influencing their cellular uptake. The aforementioned results indicated that the acid group in protein played an important role in enhancing the transfection efficiency of CS/BSA/DNA complexes and the study provided the guideline in design of an efficient vector for DNA transfection.
- Real-time monitoring of relative Peptide-protein interaction strengths in the yeast two-hybrid system. [Journal Article]
- Assay Drug Dev Technol 2013 May; 11(4):269-75.
Abstract The yeast two-hybrid (Y2H) system is one of the most technically straightforward, effective, and widely used tools for the discovery of the binary peptide or protein interactions. However, its exceptional detection sensitivity poses a serious challenge for affinity ranking and hence prioritizing the resultant large number of putative interactors for follow-up analyses. To overcome this apparent bottleneck, we describe here a novel yeast growth curve-based interaction-monitoring approach that permits semiautomatic quantification, comparison, and statistically ascertained scoring of a large collection of Y2H interactions under real-time conditions. Initially, we conducted a proof-of-concept test of five literature-validated peptide-protein interactions with known affinities in the low μM range, and subsequently used the method to classify 88 novel vitamin D receptor-binding peptides derived from high-throughput screening of a highly diverse artificial peptide aptamer library. Based on our in-depth data evaluation, we conclude that real-time monitoring of clone growth as a measure of relative binding strength offers a facile, cost-effective, accurate, reproducible, and further adaptable complement to standard Y2H-derived clone management.
- Chaos pass filter: Linear response of synchronized chaotic systems. [JOURNAL ARTICLE]
- Phys Rev E Stat Nonlin Soft Matter Phys 2013 Apr; 87(4-1):042923.
The linear response of synchronized time-delayed chaotic systems to small external perturbations, i.e., the phenomenon of chaos pass filter, is investigated for iterated maps. The distribution of distances, i.e., the deviations between two synchronized chaotic units due to external perturbations on the transferred signal, is used as a measure of the linear response. It is calculated numerically and, for some special cases, analytically. Depending on the model parameters this distribution has power law tails in the region of synchronization leading to diverging moments of distances. This is a consequence of multiplicative and additive noise in the corresponding linear equations due to chaos and external perturbations. The linear response can also be quantified by the bit error rate of a transmitted binary message which perturbs the synchronized system. The bit error rate is given by an integral over the distribution of distances and is calculated analytically and numerically. It displays a complex nonmonotonic behavior in the region of synchronization. For special cases the distribution of distances has a fractal structure leading to a devil's staircase for the bit error rate as a function of coupling strength. The response to small harmonic perturbations shows resonances related to coupling and feedback delay times. A bidirectionally coupled chain of three units can completely filter out the perturbation. Thus the second moment and the bit error rate become zero.
- Interactions of Alkylphosphocholines with Model Membranes-The Langmuir Monolayer Study. [JOURNAL ARTICLE]
- J Membr Biol 2013 May 15.
Alkylphosphocholines (APCs) belong to a class of synthetic antitumor lipids, which are new-generation anticancer agents. In contrast to traditional antitumor drugs, they do not attack the cell nucleus but, rather, the cellular membrane; however, their mechanism of action is not fully understood. This work compared the interactions of selected APCs [namely, hexadecylphosphocholine (miltefosine), octadecylphosphocholine and erucylphosphocholine] with the most important membrane lipids [cholesterol, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)] and examined their influence on a model membrane of tumor and normal cells. As a simple model of membranes, Langmuir monolayers prepared by mixing cholesterol either with a saturated phosphatidylcholine (DPPC), for a normal cell membrane, or with an unsaturated one (POPC), for a tumor cell membrane, have been applied. The APC-lipid interactions, based on experimental surface pressure (π) versus mean molecular area (A) isotherms, were analyzed qualitatively (with mean molecular area values) as well as quantitatively (with the ΔG (exc) function). Strong attractive interactions were observed for mixtures of APCs with cholesterol, contrary to the investigated phosphatidylcholines, for which the interactions were found to be weak with a tendency to separation of film components. In ternary monolayers it has been found that the investigated model systems (cholesterol/DPPC/APC vs cholesterol/POPC/APC) differ significantly as regards the interactions between film-forming molecules. The results demonstrate stronger interactions between the components of cholesterol/POPC/APC monolayers compared to cholesterol/POPC film, mimicking tumor cell membranes. In contrast, the interactions in cholesterol/DPPC/APC films were found to be weaker than those in the cholesterol/DPPC system, serving as a model of healthy cell membranes, thus proving that the incorporation of APCs is, from a thermodynamic point of view, unfavorable for binary cholesterol/DPPC monolayers. It can be concluded that the composition of healthy cell membranes is a natural barrier preventing the incorporation of APCs into normal cells.
- [Metabolism study of asperosaponin VI by using zebrafish]. [English Abstract, Journal Article]
- Yao Xue Xue Bao 2013 Feb; 48(2):281-5.
Model organism zebrafish was used to study metabolism of asperosaponin VI from Dipsacus asper Wall. ex Henry for the first time. Metabolic components of asperosaponin VI after exposing to zebrafish for 24 h were identified by high performance liquid chromatography--electrospray mass spectrometry (HPLC-ESI-MS), the separation was performed with a Zorbax C18 column using a binary gradient elution of 0.05% formic acetonitrile--0.05% formic acid water. The quasi-molecular ions of compounds in both negative and positive mode were observed for molecule mass information, and the potential structures were identified by attentive study on the deglycosylation metabolites and one hydroxylation metabolite of asperosaponin VI. The results were highly in consistent with metabolism of asperosaponin VI in rat. It can be concluded that zebrafish model can wonderfully imitate current metabolic model with advantages of small amount of lower cost, far less amount compound, higher efficiency and more simple, and can reflect integrated metabolism results of in vivo method. Zebrafish metabolic model may become a novel organism model for quick predication on metabolism of even mircoamount compound, which can enrich the available models greatly.
- Clinical use of crizotinib for the treatment of non-small cell lung cancer. [Journal Article]
- Biologics 2013.:91-101.
Discoveries over the last decade have fundamentally transformed the way we define lung cancer. Gone are the days of the simple binary classification system of non-small cell lung cancer (NSCLC) and small cell lung cancer. Today, accurate identification of the histological and molecular subtype of NSCLC is required for selecting standard cytotoxic chemotherapy and targeted therapies. The identification of anaplastic lymphoma kinase (ALK) rearrangements in 5-7% of NSCLC patients and the rapid clinical development of crizotinib for these patients is the most recent clinical example necessitating the proper identification of the molecular characteristics of NSCLC for treatment decisions. The discovery of ALK rearrangements in NSCLC serendipitously coincided with the development of crizotinib for other ALK or MET driven malignancies. The clinical development of crizotinib for ALK-positive NSCLC patients has been an amazing success story of translational medicine that relied on the prior clinical experience of other targeted predecessors (i.e. erlotinib in EGFR mutant NSCLC) and a compound ready for clinical development to gain expedited FDA approval. This review discusses the clinical development and use of crizotinib in NSCLC.