Angiotensin Converting Enzyme in Alzheimer''s Disease: Increased Activity in Caudate Nucleus and Cortical Areas

The activity of the dipeptidyl carboxypeptidase, angiotensin converting enzyme, was assayed in several brain regions of patients dying with Alzheimer's disease and compared to that of appropriately age-matched controls. Enzyme activity was found to be elevated by 44% and 41% in the medial hippocampus and parahippocampal gyrus, respectively, and by 27% and 29% in the frontal cortex (area 10 of Brodman) and caudate nucleus, respectively, in Alzheimer's disease patients. Converting enzyme activity did not differ from controls in the nucleus accumbens, substantia nigra, temporal cortex, anterior or posterior hippocampus, amydgala, and septal nuclei.     

Tyrosine Hydroxylase Activity in Caudate Nucleus from Parkinson''s Disease: Effects of Iron and Phosphorylating Agents

Tyrosine hydroxylase (TH) activity of human postmortem brain tissues from controls and patients with Parkinson's disease (PD) was examined in the presence of Fe2+ and phosphorylation agents, such as cyclic AMP, exogenous protein kinase, calcium plus calmodulin (Ca2+-CaM), and ATP. TH activity from parkinsonian tissue was increased by 48% with statistical significance in the presence of exogenous protein kinase. Cyclic AMP alone had no effect, whereas Ca2+-CaM increased the activity by only 10%. The presence of acetylcholine resulted in a slight decrease in enzyme activity. Human TH was stimulated 13.17-fold in the presence of 1 mM Fe2+. For iron dependence, no significant differences could be shown for the Km values of TH in striata of PD, while the activity of TH was half of that of controls. Here stimulation with 1 mM Fe2+ raised the activity of TH 11-fold. Stimulation of rat, gerbil, pig, and human caudate nucleus TH with Fe2+ shows remarkable species differences. In particular, the sensitivity of human TH to stimulating processes is noteworthy. H2O2 decreases TH activity only at high concentrations. Species differences are noted for the combined incubation of Fe2+ and H2O2. In the gerbil caudate nucleus, H2O2 does not prevent the stimulating properties of Fe2+, while the pig shows a dose-dependent decline of TH activity. In conclusion, there are no significant changes in the stimulating properties of human caudate nucleus TH activity with Fe2+ in PD, while such differences are noted by using exogenous protein kinase. Furthermore, experimental evidence shows that TH activity declines at high concentrations of H2O2 only. Potentiation of this effect by Fe2+ seems to be species-dependent.     

Telomerase Activity Impacts on Epstein-Barr Virus Infection of AGS Cells

The Epstein-Barr virus (EBV) is transmitted from host-to-host via saliva and is associated with epithelial malignancies including nasopharyngeal carcinoma (NPC) and some forms of gastric carcinoma (GC). Nevertheless, EBV does not transform epithelial cells in vitro where it is rapidly lost from infected primary epithelial cells or epithelial tumor cells. Long-term infection by EBV, however, can be established in hTERT-immortalized nasopharyngeal epithelial cells. Here, we hypothesized that increased telomerase activity in epithelial cells enhances their susceptibility to infection by EBV. Using HONE-1, AGS and HEK293 cells we generated epithelial model cell lines with increased or suppressed telomerase activity by stable ectopic expression of hTERT or of a catalytically inactive, dominant negative hTERT mutant. Infection experiments with recombinant prototypic EBV (rB95.8), recombinant NPC EBV (rM81) with increased epithelial cell tropism compared to B95.8, or recombinant B95.8 EBV with BZLF1-knockout that is not able to undergo lytic replication, revealed that infection frequencies positively correlate with telomerase activity in AGS cells but also partly depend on the cellular background. AGS cells with increased telomerase activity showed increased expression mainly of latent EBV genes, suggesting that increased telomerase activity directly acts on the EBV infection of epithelial cells by facilitating latent EBV gene expression early upon virus inoculation. Thus, our results indicate that infection of epithelial cells by EBV is a very selective process involving, among others, telomerase activity and cellular background to allow for optimized host-to-host transmission via saliva.     

Relationship between Oscillatory Neuronal Activity during Reward Processing and Trait Impulsivity and Sensation Seeking

Background

The processing of reward and punishment stimuli in humans appears to involve brain oscillatory activity of several frequencies, probably each with a distinct function. The exact nature of associations of these electrophysiological measures with impulsive or risk-seeking personality traits is not completely clear. Thus, the aim of the present study was to investigate event-related oscillatory activity during reward processing across a wide spectrum of frequencies, and its associations with impulsivity and sensation seeking in healthy subjects.

Methods

During recording of a 32-channel EEG 22 healthy volunteers were characterized with the Barratt Impulsiveness and the Sensation Seeking Scale and performed a computerized two-choice gambling task comprising different feedback options with positive vs. negative valence (gain or loss) and high or low magnitude (5 vs. 25 points).

Results

We observed greater increases of amplitudes of the feedback-related negativity and of activity in the theta, alpha and low-beta frequency range following loss feedback and, in contrast, greater increase of activity in the high-beta frequency range following gain feedback. Significant magnitude effects were observed for theta and delta oscillations, indicating greater amplitudes upon feedback concerning large stakes. The theta amplitude changes during loss were negatively correlated with motor impulsivity scores, whereas alpha and low-beta increase upon loss and high-beta increase upon gain were positively correlated with various dimensions of sensation seeking.

Conclusions

The findings suggest that the processing of feedback information involves several distinct processes, which are subserved by oscillations of different frequencies and are associated with different personality traits.     

Structure Activity Relationship of Dendrimer Microbicides with Dual Action Antiviral Activity

Background

Topical microbicides, used by women to prevent the transmission of HIV and other sexually transmitted infections are urgently required. Dendrimers are highly branched nanoparticles being developed as microbicides. However, the anti-HIV and HSV structure-activity relationship of dendrimers comprising benzyhydryl amide cores and lysine branches, and a comprehensive analysis of their broad-spectrum anti-HIV activity and mechanism of action have not been published.

Methods and Findings

Dendrimers with optimized activity against HIV-1 and HSV-2 were identified with respect to the number of lysine branches (generations) and surface groups. Antiviral activity was determined in cell culture assays. Time-of-addition assays were performed to determine dendrimer mechanism of action. In vivo toxicity and HSV-2 inhibitory activity were evaluated in the mouse HSV-2 susceptibility model. Surface groups imparting the most potent inhibitory activity against HIV-1 and HSV-2 were naphthalene disulfonic acid (DNAA) and 3,5-disulfobenzoic acid exhibiting the greatest anionic charge and hydrophobicity of the seven surface groups tested. Their anti-HIV-1 activity did not appreciably increase beyond a second-generation dendrimer while dendrimers larger than two generations were required for potent anti-HSV-2 activity. Second (SPL7115) and fourth generation (SPL7013) DNAA dendrimers demonstrated broad-spectrum anti-HIV activity. However, SPL7013 was more active against HSV and blocking HIV-1 envelope mediated cell-to-cell fusion. SPL7013 and SPL7115 inhibited viral entry with similar potency against CXCR4-(X4) and CCR5-using (R5) HIV-1 strains. SPL7013 was not toxic and provided at least 12 h protection against HSV-2 in the mouse vagina.

Conclusions

Dendrimers can be engineered with optimized potency against HIV and HSV representing a unique platform for the controlled synthesis of chemically defined multivalent agents as viral entry inhibitors. SPL7013 is formulated as VivaGel® and is currently in clinical development to provide protection against HIV and HSV. SPL7013 could also be combined with other microbicides.     

Action Research as a Professional Development Activity

Reflective teachers are always searching for ways to improve their teaching. When this reflection becomes intentional and systematic, they are engaging in teacher research. This type of research, sometimes called action research, can help bridge the gap between theory and practice by addressing topics that are relevant to practicing teachers. This article synthesizes literature within music education and general education to address (a) the conceptual underpinnings of action research, (b) characteristics of action research and teacher research, (c) action research critiques, and (d) implications for teacher research as a form of professional development.     

牛乳铁蛋白素抗菌活性及抗菌活性位点

牛乳铁蛋白素(Bovine Lactoferrcin, LfcinB)是乳铁蛋白在酸性环境下经胃蛋白酶作用N端释放的一段多肽, 它具有多种生物学功能。研究LfcinB广谱抗菌性及改变LfcinB氨基酸序列对其抗菌能力的影响, 寻找LfcinB抗菌作用的结构位点。人工合成LfcinB, 采用琼脂扩散法测定LfcinB抗菌图谱。人工合成丙氨酸取代3位半胱氨酸的LfcinB、丙氨酸取代8位色氨酸的LfcinB和去掉2个半胱氨酸的LfcinB样品, 测定最小抑菌浓度, 确定LfcinB抗菌活性位点。研究结果表明:     

Action of β-N-Oxalylamino-l-Alanine on Mouse Brain NADH-Dehydrogenase Activity

Abstract: β- N -Oxalylamino- l -alanine ( l -BOAA), a non-protein neuroexcitatory amino acid present in the seeds of Lathyrus sativus (chickling or grass pea), is known to produce its neurotoxic effects by overstimulation of non- N -methyl- d -aspartate receptors, especially α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors, at micromolar concentrations. It has recently been reported that l -BOAA selectively inhibits mitochondrial enzyme NADH-dehydrogenase (NADH-DH) in brain slices at subpicomolar concentrations. The present study finds that up to 4 m M concentrations of pure l -BOAA fail to inhibit NADH-DH activity in mouse brain homogenate and isolated brain mitochondria. Two known inhibitors (rotenone and 1-methyl-4-phenylpyridinium ion, MPP⁺) of this mitochondrial enzyme produced significant inhibition under identical conditions. NADH-DH inhibition was also not observed in the homogenate or mitochondria from the brains of animals systemically treated with convulsive doses of l -BOAA. Some inhibition (20–37%) of NADH-DH activity was observed in mouse brain slices incubated with 100–1,000 µ M concentrations of l -BOAA for 1 h at 37°C in an atmosphere of 95% O₂ and 5% CO₂, but the inhibition was nonselective, because the activity of another mitochondrial enzyme, succinic dehydrogenase, was similarly inhibited by l -BOAA. These results are in contrast with the report that l -BOAA inhibits mitochondrial NADH-DH selectively at subpicomolar concentrations. We suggest the observed nonselective NADH-DH inhibition in mouse brain slices treated with l -BOAA is caused by neuronal damage through an excitotoxic mechanism.     

Hypolipidemic Activity and Mechanism of Action of Sargassum fusiforme Polysaccharides

Sargassum fusiforme polysaccharide (SFP) is a kind of biologically active macromolecule with biological functions. In this study, oxidative stress and high-fat HepG2 cell models were established to investigate its lipid-lowering activity and mechanism of action. It was found that SFP and its two isolated fractions had antioxidant effects on the cells. It was also found the polysaccharides decreased the content of total cholesterol and total triglyceride in the high-fat cells. RT-qPCR assays revealed that the three polysaccharides down-regulated the mRNA expression level of ACC, PPARγ, and SREBP-2. It could be concluded that the hypolipidemic effect of SFPs is achieved via multiple pathways, including the regulation on the expression level of lipid metabolism-related key enzymes and factors, and binding with bile acids. The hypolipidemic effect of SFPs could be partially due to their antioxidant activity. SFPs developed in the present work have potential as ingredients of functional foods with hypolipidemic effect.     

Phenome-Wide Association Studies on a Quantitative Trait: Application to TPMT Enzyme Activity and Thiopurine Therapy in Pharmacogenomics

Phenome-Wide Association Studies (PheWAS) investigate whether genetic polymorphisms associated with a phenotype are also associated with other diagnoses. In this study, we have developed new methods to perform a PheWAS based on ICD-10 codes and biological test results, and to use a quantitative trait as the selection criterion. We tested our approach on thiopurine S-methyltransferase (TPMT) activity in patients treated by thiopurine drugs. We developed 2 aggregation methods for the ICD-10 codes: an ICD-10 hierarchy and a mapping to existing ICD-9-CM based PheWAS codes. Eleven biological test results were also analyzed using discretization algorithms. We applied these methods in patients having a TPMT activity assessment from the clinical data warehouse of a French academic hospital between January 2000 and July 2013. Data after initiation of thiopurine treatment were analyzed and patient groups were compared according to their TPMT activity level. A total of 442 patient records were analyzed representing 10,252 ICD-10 codes and 72,711 biological test results. The results from the ICD-9-CM based PheWAS codes and ICD-10 hierarchy codes were concordant. Cross-validation with the biological test results allowed us to validate the ICD phenotypes. Iron-deficiency anemia and diabetes mellitus were associated with a very high TPMT activity (p = 0.0004 and p = 0.0015, respectively). We describe here an original method to perform PheWAS on a quantitative trait using both ICD-10 diagnosis codes and biological test results to identify associated phenotypes. In the field of pharmacogenomics, PheWAS allow for the identification of new subgroups of patients who require personalized clinical and therapeutic management.     

KRAS Dimerization Impacts MEK Inhibitor Sensitivity and Oncogenic Activity of Mutant KRAS

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Direct Action of Insulin on Plasma Membrane ATPase Activity in Human Lymphocytes

LITTLE is known about the effects of insulin on lymphocytes. Helmreich and Eisen¹ concluded that it has insignificant effects, but others^2–5 have made a case for a role in inflammatory and immunological responses. We^6,7 have demonstrated that noradrenaline enhances the uptake of both glucose and potassium by lymphocytes, as does insulin in several tissues. We have associated this action of noradrenaline with a direct effect on membrane adenosine triphosphatase (ATPase) activity⁷. The observation⁸ that insulin bound to ‘Sepharose’ polymers enhances glucose transport while in contact only with the plasma membrane indicated that insulin might have a direct action similar to that of noradrenaline on membrane ATPase. The observations reported here show that insulin stimulates ATPase activity and glucose uptake in the lymphocyte and suggest a relationship between membrane ATPase activity and glucose transport.     

Anticonvulsant and Antioxidant Effects of Cyano-carvone and Its Action on Acetylcholinesterase Activity in Mice Hippocampus

The anticonvulsant effect of cyano-carvone, a monoterpene monocyclic, was investigated in epilepsy model induced by pilocarpine. Cyano-carvone at doses of 25, 50 or 75 mg/kg promoted a reduction of 16.7, 33 and 66.7%, respectively, against pilocarpine-induced seizures, and it was efficacious in increasing both the latency to first seizures and the survival percentage, resulting in 33.3, 67 and 91.7% of protection against death induced by seizures, respectively (P < 0.05). The reference drug atropine (25 mg/kg) also produced a significant protection (100%). Its monoterpene, at 25, 50 and 75 mg/kg, was also capable to increase the latency for installation of status epilepticus induced by pilocarpine, and presented a significant protection against lipid peroxidation and nitrite formation in mice hippocampus (P < 0.05). In addition, it was observed that the cyano-carvone pretreatment increased the acetylcholinesterase activity in mice hippocampus after pilocarpine-induced seizures. The present results clearly indicate the anticonvulsant ability of cyano-carvone, which can be, at least in part, explained by the increased activity of the acetylcholinesterase enzyme. Our data suggest that the action mechanism can also be due to a direct activation of the antioxidant enzymes that could be associated with a reduction observed in oxidative stress in mice hippocampus, probably involving an inhibition of free radical production.     

Effects of Genetic and Environmental Factors on Trait Network Predictions From Quantitative Trait Locus Data

The use of high-throughput genomic techniques to map gene expression quantitative trait loci has spurred the development of path analysis approaches for predicting functional networks linking genes and natural trait variation. The goal of this study was to test whether potentially confounding factors, including effects of common environment and genes not included in path models, affect predictions of cause–effect relationships among traits generated by QTL path analyses. Structural equation modeling (SEM) was used to test simple QTL-trait networks under different regulatory scenarios involving direct and indirect effects. SEM identified the correct models under simple scenarios, but when common-environment effects were simulated in conjunction with direct QTL effects on traits, they were poorly distinguished from indirect effects, leading to false support for indirect models. Application of SEM to loblolly pine QTL data provided support for biologically plausible a priori hypotheses of QTL mechanisms affecting height and diameter growth. However, some biologically implausible models were also well supported. The results emphasize the need to include any available functional information, including predictions for genetic and environmental correlations, to develop plausible models if biologically useful trait network predictions are to be made.     

超声波对猪胰脂肪酶催化活性影响的机理研究

猪胰脂肪酶(porcine pancreas Lipase,PPL)反应系统经适宜参数的超声波处理,催化活性提高了11.22%～24.42%。PPL经超声波处理后,其动力学参数Km和Vmax都变小,酶分子的紫外吸收光谱不变,荧光发射光谱不变。而酶分子经超声波处理后,其紫外差示光谱出现了明显的正峰或负峰。探讨了超声波影响PPL活性的作用机理。