Modulation of biochemical activity of hepatocytes in culture by matrix substratum

If critical care nurses and advanced practice nurses could identify patients with an increased risk of an unsuccessful outcome from cardiac arrest resuscitation in the hospital, such patients could be monitored with a heightened vigilance. This is the first nursing study to examine pre-existing variables and outcome of cardiac arrest resuscitation in hospitalized patients. The investigators found that heart rate and respiratory rate increased significantly 8 hours before the cardiac arrest in patients with an unsuccessful outcome of resuscitation.     

Structural characteriztion of Nd-doped in silica host matrix prepared by net chemical process

Silica host matrix containing neodymium which is potentially important for the formation of nanocrystalline metal oxides was prepared by solgel method, using tetra-ethoxysilane and Nd(NO3)3 as precursor materials. The prepared samples were changed from amorphous to nanocrystallites phase at sintered temperature 550℃ (4 h), 750℃ (8 h) and 950 ℃ (12 h). The thermally treated sample microstructures were investigated using X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). While a further increase of the temperature at 750 ℃ and annealing time (8 h) resulted in the formation of cubic and hexagonal Nd2O3 nanocrystallites. At constant sintering temperature 950℃ for 12 h, the samples showed sharper and intense peaks. The sizes of Nd2O3 nanocrystallites were characterized by XRD with average size～46 nm.     

Failure to induce nitric oxide production by human monocyte-derived macrophages. Manipulation of biochemical pathways

Production of nitrix oxide (NO-) by human macrophages is controversial. In the present study, the ability of human monocyte-derived macrophages (M phi) to produce NO- in response to M phi modulators was tested. M phi cultured for up to nine days and stimulated for 48 with different concentrations of LPS and/or IFN-gamma failed to produce significant amounts of NO2- compared to unstimulated cultures. Inhibition of the cyclo-oxygenase pathway with indomethacin did not increase NO2- production by LPS stimulated M phi. Since human M phi lack biopterin, needed for NO- synthesis by murine M phi, human M phi stimulated with LPS plus IFN-gamma were additionally cultured in the presence of neopterin or biopterin. These treatments did not induce NO2- production. Furthermore, simultaneous treatment with indomethacin and neopterin or biopterin also failed to induce NO2- production. However, human M phi, stimulated with IFN-gamma and LPs, produced TNF-alpha suggesting that the lack of increment in NO2- production was not due to an absence of response of M phi to the stimuli used. As an indirect approach to explore the NO- production, human M phi were infected with virulent Mycobacterium tuberculosis H37Rv and simultaneously treated with the competitive inhibitor NGmonomethyl-L-arginine (NGMMA). Mycobacterial intracellular replication was measured by 3H-uracil incorporation. NGMMA did not have any effect on mycobacterial replication. These results further suggest that human M phi do not produce NO- at least by the inducible pathway.     

Determination of rate and equilibrium constants for some typical biochemical reactions

Three types of typical biological reactions are considered. Their kinetic curves plotted in the semilogarithmic scale are approximated well by two lines intercepting at different angles and may be described with the systems of differential equations. The latters are resolved as a complex system of transcendental irrational equations interconnecting the reagent concentrations, time and rate constants. A new method for numerical solution of such equations is suggested which permits determining the exact rate constants on the basis of either theoretical or experimental kinetic curves.     

Microcalorimetric and biochemical investigations of thermogenesis and metabolic pathways in human white adipocytes

OBJECTIVE: Validation of a novel culture technique for human white adipocytes, facilitating direct microcalorimetry and simultaneously performed biochemistry for 3 days. DESIGN: Subcutaneous adipocytes were cultured in a 3-dimensional matrix of agarose gel. Biochemical measures were obtained every 24 h, while thermogenesis was continuously monitored for 72 h. DNA content of the cultures served as reference. SUBJECTS: 73 men and women undergoing uncomplicated surgery. MEASUREMENTS: Cell viability (LDH release), total cellular thermogenesis, oxygen consumption, glycolysis, lipolysis (basal, catecholamin-stimulated) triglyceride/free fatty acid substrate cycle, adenine nucleotides, insulin-induced thermogenesis. RESULTS: LDH release was 0.4% of total LDH per hour. Cellular ATP, ADP and AMP (3.77, 0.39 and 0.06 nmol/microgramDNA, resp.) were constant. The rates of glucose consumption, lactate and pyruvate production and basal glycerol release (56.4, 43.1, 2.7 and 28.1 nmol/microgramDNA.h, resp.) were stable during 72 h. Isoprenaline (1 microM) enhanced lipolytic rate by the same extent at any time of the study (glycerol release 67.8 nmol/microgramDNA.h). FFA release (initially 26.0 nmol/ microgramDNA.h) declined during the experiment, due to an increase of reesterfication rate. Unstimulated heat production was 6.5 microW/microgramDNA, 68% of which were of oxidative origin. Insulin (0.1 microM) induced thermogenesis was 8.8 microW/ microgramDNA. CONCLUSION: The results were in accordance with data from human white adipocytes in suspensions. However, in contrast to fat cell suspensions, gel cultured adipocytes were viable for 3 days without metabolic alterations.     

Non-linear optimization of biochemical pathways: applications to metabolic engineering and parameter estimation

MOTIVATION: The simulation of biochemical kinetic systems is a powerful approach that can be used for: (i) checking the consistency of a postulated model with a set of experimental measurements, (ii) answering 'what if?' questions and (iii) exploring possible behaviours of a model. Here we describe a generic approach to combine numerical optimization methods with biochemical kinetic simulations, which is suitable for use in the rational design of improved metabolic pathways with industrial significance (metabolic engineering) and for solving the inverse problem of metabolic pathways, i.e. the estimation of parameters from measured variables. RESULTS: We discuss the suitability of various optimization methods, focusing especially on their ability or otherwise to find global optima. We recommend that a suite of diverse optimization methods should be available in simulation software as no single one performs best for all problems. We describe how we have implemented such a simulation-optimization strategy in the biochemical kinetics simulator Gepasi and present examples of its application. AVAILABILITY: The new version of Gepasi (3.20), incorporating the methodology described here, is available on the Internet at http://gepasi.dbs.aber.ac.uk/softw/Gepasi. html. CONTACT: prm@aber.ac.uk     

Prospective biochemical and scintigraphic evaluation of autografted normal parathyroid glands in patients undergoing thyroid operations

Recent reports suggest that oral choline supplement may alter the cerebral choline/creatine (Cho/Cr) ratio and might be used to treat neurodegenerative disorders of cholinergic transmission. Using both 1H and 31P MRS, we reexamined the Cho/Cr ratio and quantified cerebral choline and its major constituents: phosphoethanolamine (PE), phosphorylcholine (PC), glycerophosphorylethanolamine (GPE), and glycerophosphorylcholine (GPC). In the four brain locations examined, no significant increases in Cho/Cr, [Cho], or in its major constituents were found in response to an oral challenge of 50 mg/kg of choline bitartrate. Oral choline did not significantly affect human cerebral metabolism in the short term.     

Calculation of standard transformed Gibbs energies and standard transformed enthalpies of biochemical reactants

The standard Gibbs energies of formation and standard enthalpies of formation of species involved in biochemical reactions are used to calculate standard transformed Gibbs energies of formation and standard transformed enthalpies of formation of 53 reactants (sums of species) at 298.15 K, pH 7, and ionic strengths of 0, 0.1, and 0. 25 M. The standard transformed Gibbs energies of formation are used to calculate apparent equilibrium constants K' for 22 biochemical reactions for which apparent equilibrium constants have been determined close to these conditions. This comparison is generally satisfactory given the differences in experimental conditions. The transformed formation properties for the 53 reactants make it possible to calculate transformed formation properties for other reactants involved in biochemical reactions with some of these reactants. This is illustrated by calculating standard transformed Gibbs energies of formation for 11 more reactants without information on the standard Gibbs energies of formation of the species. The list of 64 reactants for which standard transformed Gibbs energies of formation are presented can be considerably extended. The use of tables of standard transformed Gibbs energies of formation to store information on apparent equilibrium constants is more efficient than simply storing apparent equilibrium constants because a reactant can be looked up in a table and may be involved in hundreds of reactions. The effects of magnesium ions on several reactions involving ATP are calculated. The advantages of using enzyme-catalyzed reactions for determining thermodynamic properties of complicated molecules in aqueous solution are discussed.     

Problems of seriation using a subject by item response matrix.

Aspects of the problem of sequencing Ss on the basis of point dichotomous items are reviewed, as are several extensions to more general items. A majority of the results that are presented have been developed by qualitatively oriented archaeologists who are faced with the task of sequencing artifacts along a time continuum; the difficulties encountered in these attempts turn out to be formally equivalent to some of the problems psychologists face in sequencing Ss on the basis of item responses. Comments are also included on the specialization to a more restrictive Guttman scale, and suggestions are given for reformulating some of the necessary terminology within a graph theory context. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Urinary pyrraline as a biochemical marker of non-oxidative Maillard reactions in vivo

The presence of pyrraline, a non-oxidative glucose-derived Maillard reaction product in plasma proteins has been established previously. In this study we have investigated the presence of pyrraline in human urine to determine whether pyrraline-containing proteins are metabolized or selectively retained. Pyrraline was detected by means of HPLC, and its presence was confirmed by UV and electrospray-mass spectrometry. The quantification of pyrraline in urine from healthy individuals showed 1.21 +/- 0.4 micrograms/mg creatinine. In urine from diabetic patients, pyrraline levels varied considerably, although the mean level was higher than in healthy subjects (1.37 +/- 0.6 micrograms/mg creatinine). These data further support the presence of a catabolic pathway for advanced non-oxidative Maillard reaction products in vivo and suggest their role in the pathogenesis of diabetes.     

Displacement reactions between Cr and MoO2 in a Ni-base alloy matrix

Displacement reactions at 1150 °C between Cr and MoO₂2 in a Ni-rich alloy matrix were studied. Depending on the Cr and Mo contents, three morphologies of the Cr₂O₃ product phase were observed: internal oxides, continuous scale, and aggregate product layer. Kinetic expressions were derived and fitted to the layer growth data. The reactions were found to be diffusion controlled and described well by quasi-steady-state fluxes. The selection by the system of the dominant product morphology was decided by the relative fluxes of chromium and oxygen solutes to the initial interface early in the reaction. Formerly Graduate Student, The Ohio State University.     

Enhancement of fibroblast collagenase (matrix metalloproteinase-1) gene expression by ceramide is mediated by extracellular signal-regulated and stress-activated protein kinase pathways

Inflammatory cytokines tumor necrosis factor-alpha and interleukin-1 trigger the ceramide signaling pathway, initiated by neutral sphingomyelinase-elicited hydrolysis of cell membrane phospholipid sphingomyelin to ceramide, a new lipid second messenger. Here, we show that triggering the ceramide pathway by sphingomyelinase or C2- and C6-ceramide enhances collagenase-1 (matrix metalloproteinase-1; MMP-1) gene expression by fibroblasts. C2-ceramide activates three distinct mitogen-activated protein kinases (MAPKs) in dermal fibroblasts, i.e. extracellular signal-regulated kinase 1/2 (ERK1/2), stress-activated protein kinase/Jun N-terminal-kinase (SAPK/JNK), and p38. Stimulation of MMP-1 promoter activity by C2-ceramide is dependent on the presence of a functional AP-1 cis-element and is entirely inhibited by overexpression of MAPK inhibitor, dual specificity phosphatase CL100 (MAPK phosphatase-1). Activation of MMP-1 promoter by C2-ceramide is also effectively inhibited by kinase-deficient forms of ERK1/2 kinase (MEK1/2) activator Raf-1, ERK1 and ERK2, SAPK/JNK activator SEK1, or SAPKbeta. In addition, ceramide-dependent induction of MMP-1 expression is potently prevented by PD 98059, a selective inhibitor of MEK1 activation, and by specific p38 inhibitor SB 203580. These results show that triggering the ceramide signaling pathway activates MMP-1 gene expression via three distinct MAPK pathways, i.e. ERK1/2, SAPK/JNK, and p38, and suggest that targeted modulation of the ceramide signaling pathway may offer a novel therapeutic approach for inhibiting collagenolytic activity, e.g. in inflammatory disorders.     

CPN攻击建模及警报相关性算法设计

为提高当前入侵检测系统的预警质量和分析预测能力,用染色Petri网(colored petrinet,CPN)构造了攻击模型,系统性地设计了警报信息相关性分析算法.通过把"警报"和"攻击"作为2个不同实体参与模型运算,将目前主要采用的过滤观察信息为基础的关联方法提升为信息推理的演算方法.应用CPN模型转换、极小覆盖集命题等方法,对本领域中的难点问题即复合攻击、合作攻击进行了理论分析和算法设计.在此基础上开发了警报信息相关性分析(alerts correlationanalvsis system,ACAS)实验系统,实验结果表明算法系统对于提高入侵检测系统的警报质量和分析预测能力是可行、有效的.     

Modification of the effects of microwave irradiation on biochemical processes by using foreign protein

The biochemical data on the influence of electromagnetic fields in microwave range on the hormonal-mediator regulation systems are presented. The possibility of biological effects modification under combined action of microwave radiation and foreign protein is discussed.     

Calculation of diffusion-limited kinetics for the reactions in collision coupling and receptor cross-linking

Both enzyme (e.g., G-protein) activation via a collision coupling model and the formation of cross-linked receptors by a multivalent ligand involve reactions between two molecules diffusing in the plasma membrane. The diffusion of these molecules is thought to play a critical role in these two early signal transduction events. In reduced dimensions, however, diffusion is not an effective mixing mechanism; consequently, zones in which the concentration of particular molecules (e.g., enzymes, receptors) becomes depleted or enriched may form. To examine the formation of these depletion/ accumulation zones and their effect on reaction rates and ultimately the cellular response, Monte Carlo techniques are used to simulate the reaction and diffusion of molecules in the plasma membrane. The effective reaction rate at steady state is determined in terms of the physical properties of the tissue and ligand for both enzyme activation via collision coupling and the generation of cross-linked receptors. The diffusion-limited reaction rate constant is shown to scale with the mean square displacement of a receptor-ligand complex. The rate constants determined in the simulation are compared with other theoretical predictions as well as experimental data.     

Reconstructive operations on the head and neck using a microsurgical technic

Eighty-one patients with defects and deformations of the head and neck of various origin were examined and treated. Microsurgical autotransplantation of vascularized tissue complexes was carried out in all the cases. Profound preliminary examinations of patients helped objectively define the indications for the use of this method. Special attention was paid to the choice of donor zone. Due to correct selection of a complex graft, good functional and cosmetic results were attained. Despite repeated corrective operations in 16 patients, virtually complete social and communal rehabilitation was attained in 74 (91.4%) patients by using a limited number of donor areas. The authors persuasively demonstrate the advantages of microsurgery in repair of complex and extensive defects on the head and neck.