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51.
The novel neurotransmitter/neuromodulator nitric oxide (NO), which is linked to the activation of the N-methyl-D-aspartate class of glutamate receptors, has been shown to modify transmitter release in brain tissue. Release of the inhibitory amino acid taurine is also markedly enhanced by N-methyl-D-aspartate and NO-producing agents under normal conditions in the mouse hippocampus. The release of preloaded [3H]taurine from hippocampal slices from adult (3-month-old) and developing (7-day-old) mice was characterized under ischemic conditions in the presence of different NO-generating compounds, hydroxylamine, sodium nitroprusside, and S-nitroso-N-acetylpenicillamine (SNAP), using a superfusion system. The ischemia-induced taurine release at both ages was markedly enhanced by 1.0 mM nitroprusside and 1.0 mM SNAP, whereas 5.0 mM hydroxylamine was effective only in adults. The nitroprusside- and SNAP-induced releases were reduced by the inhibitors of NO synthase (nitroarginine and 7-nitroindazole) and NO-sensitive soluble guanylyl cyclase [1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one], suggesting involvement of the NO/cGMP pathway. The release in ischemia in the absence of Na+ was modified by NO compounds only in adults; the 0.1 mM N-methyl-D-aspartate stimulated taurine release at both ages. The enhanced release of taurine associated with NO production could be beneficial to brain tissue under cell-damaging conditions and corroborates the neuroprotective role of this amino acid, particularly in the immature brain. 相似文献
52.
Kari Seppänen Reino Laatikainen Jukka T. Salonem Marjatta Kantola Simo Lötjönen Mikko Harri Llisa Nüurminen Jari Kaikkomem Kristiima Nyyssönen 《Biological trace element research》1998,65(3):197-210
The mercury-binding capacity of seleno-DL-methionine and selenium dioxide was assessed in male Wistar rats. Mercury was supplied
as fish loaves made of northern pike or rainbow trout. We used a selenium concentration of 3.4 mg/kg fish, about sixfold compared
to the equivalent quantity of mercury. Seleno-DL-methionine had a tendency to increase both methyl mercury and total mercury
in blood, although it also seemed to reduce the proportion of methyl mercury of total mercury. Selenium dioxide lowered mercury
levels by 24–29% both in the blood and in the liver of rats that were fed with northern pike. 相似文献
53.
Simo O Lee VP Davis AS Kreutz C Gross PH Jones PR Michael K 《Carbohydrate research》2005,340(4):557-566
The glycosylamines of O-acetyl-protected GlcNAc and chitobiose, as well as two partially unprotected 1-C-aminomethyl glucosides, were photochemically coupled with orthogonally protected N-aspartyl-5-bromo-7-nitroindoline derivatives. The reactions proceeded under neutral conditions by irradiation with near-UV light. The glycosyl asparagines with N- or C-glycosyl linkages were afforded in 60-85% yield on a 10-70 mg scale. Moreover, the ability of a highly photoreactive N-glutamyl-4-methoxy-7-nitroindoline derivative to acylate amino saccharides was tested. Upon irradiation in the presence of a dimeric 1-C-aminomethyl glycoside, or a glycosylamine, the corresponding glycosyl glutamines were obtained in 50% and 30% yield, respectively. Preparations of the photoreactive aspartates and the 1-C-aminomethyl glycosides are also described. 相似文献
54.
Eremin KO Kudrin VS Saransaari P Oja SS Grivennikov IA Myasoedov NF Rayevsky KS 《Neurochemical research》2005,30(12):1493-1500
Corticotrophin (ACTH) and its analogues, particularly Semax (Met-Glu-His-Phe-Pro-Gly-Pro), demonstrate nootropic activity.
Close functional and anatomical links have been established between melanocortinergic and monoaminergic brain systems. The
aim of present work was to investigate the effects of Semax on neurochemical parameters of dopaminergic- and serotonergic
systems in rodents. The tissue content of 5-hydroxyindoleacetic acid (5-HIAA) in the striatum was significantly increased
(+25%) 2 h after Semax administration. The extracellular striatal level of 5-HIAA gradually increased up to 180% within 1–4 h
after Semax (0.15 mg/kg, ip) administration. This peptide alone failed to alter the tissue and extracellular concentrations
of dopamine and its metabolites. Semax injected 20 min prior d-amphetamine dramatically enhanced the effects of the latter on the extracellular level of dopamine and on the locomotor activity
of animals. Our results reveal the positive modulatory effect of Semax on the striatal serotonergic system and the ability
of Semax to enhance both the striatal release of dopamine and locomotor behavior elicited by d-amphetamine.
Special issue dedicated to Dr. Simo S. Oja. 相似文献
55.
Simo G Herder S Njiokou F Asonganyi T Tilley A Cuny G 《Experimental parasitology》2005,110(4):353-362
To better understand the epidemiology of sleeping sickness in the Central African sub-region, notably the heterogeneity of Human African Trypanosomiasis (HAT) foci, the mobile genetic element PCR (MGE-PCR) technique was used to genotype Trypanosoma brucei s.l. (T. brucei s.l.) isolates from this sub-region. Using a single primer REV B, which detects positional variation of the mobile genetic element RIME, via amplification of flanking regions, MGE-PCR revealed a micro genetic variability between Trypanosoma brucei gambiense (T. b. gambiense) isolates from Central Africa. The technique also revealed the presence of several T. b. gambiense genotypes and allowed the identification of minor and major ubiquitous genotypes in HAT foci. The presence of several T. b. gambiense genotypes in HAT foci may explain the persistence and the resurgence phenomena of the disease and also the epidemic and the endemic status of some Central African sleeping sickness foci. The MGE-PCR technique represents a simple, rapid, and specific method to differentiate Central African T. brucei s.l. isolates. 相似文献
56.
Ugutz Unzueta Felicitas Vázquez Giulia Accardi Rosa Mendoza Verónica Toledo-Rubio Maria Giuliani Filomena Sannino Ermenegilda Parrilli Ibane Abasolo Simo Schwartz Jr. Maria L. Tutino Antonio Villaverde José L. Corchero Neus Ferrer-Miralles 《Applied microbiology and biotechnology》2015,99(14):5863-5874
57.
Rinez Thapa Subhasish Mondal Joakim Riikonen Jimi Rantanen Simo Nkki Tuomo Nissinen Ale Nrvnen Vesa-Pekka Lehto 《PLoS neglected tropical diseases》2021,15(6)
Visceral leishmaniasis is a vector-borne protozoan infection that is fatal if untreated. There is no vaccination against the disease, and the current chemotherapeutic agents are ineffective due to increased resistance and severe side effects. Buparvaquone is a potential drug against the leishmaniases, but it is highly hydrophobic resulting in poor bioavailability and low therapeutic efficacy. Herein, we loaded the drug into silicon nanoparticles produced from barley husk, which is an agricultural residue and widely available. The buparvaquone-loaded nanoparticles were several times more selective to kill the intracellular parasites being non-toxic to macrophages compared to the pure buparvaquone and other conventionally used anti-leishmanial agents. Furthermore, the in vivo results revealed that the intraperitoneally injected buparvaquone-loaded nanoparticles suppressed the parasite burden close to 100%. By contrast, pure buparvaquone suppressed the burden only by 50% with corresponding doses. As the conclusion, the biogenic silicon nanoparticles are promising carriers to significantly improve the therapeutic efficacy and selectivity of buparvaquone against resistant visceral leishmaniasis opening a new avenue for low-cost treatment against this neglected tropical disease threatening especially the poor people in developing nations. 相似文献
58.
Gupta RD Goldsmith M Ashani Y Simo Y Mullokandov G Bar H Ben-David M Leader H Margalit R Silman I Sussman JL Tawfik DS 《Nature chemical biology》2011,7(2):120-125
Organophosphate nerve agents are extremely lethal compounds. Rapid in vivo organophosphate clearance requires bioscavenging enzymes with catalytic efficiencies of >10(7) (M(-1) min(-1)). Although serum paraoxonase (PON1) is a leading candidate for such a treatment, it hydrolyzes the toxic S(p) isomers of G-agents with very slow rates. We improved PON1's catalytic efficiency by combining random and targeted mutagenesis with high-throughput screening using fluorogenic analogs in emulsion compartments. We thereby enhanced PON1's activity toward the coumarin analog of S(p)-cyclosarin by ~10(5)-fold. We also developed a direct screen for protection of acetylcholinesterase from inactivation by nerve agents and used it to isolate variants that degrade the toxic isomer of the coumarin analog and cyclosarin itself with k(cat)/K(M) ~ 10(7) M(-1) min(-1). We then demonstrated the in vivo prophylactic activity of an evolved variant. These evolved variants and the newly developed screens provide the basis for engineering PON1 for prophylaxis against other G-type agents. 相似文献
59.
60.
Sinem DEMRBA-SARIKAYA Hatice AKIR Devrim G
ZÜAIK Yunus AKKO 《Turkish Journal of Biology》2021,45(3):235
Autophagy and DNA repair are two essential biological mechanisms that maintain cellular homeostasis. Impairment of these mechanisms was associated with several pathologies such as premature aging, neurodegenerative diseases, and cancer. Intrinsic or extrinsic stress stimuli (e.g., reactive oxygen species or ionizing radiation) cause DNA damage. As a biological stress response, autophagy is activated following insults that threaten DNA integrity. Hence, in collaboration with DNA damage repair and response mechanisms, autophagy contributes to the maintenance of genomic stability and integrity. Yet, connections and interactions between these two systems are not fully understood. In this review article, current status of the associations and crosstalk between autophagy and DNA repair systems is documented and discussed. 相似文献