Search results for "specificity"
showing 10 items of 2234 documents
Inter-laboratory validation of procedures for measuring 8-oxo-7,8-dihydroguanine/8-oxo-7,8-dihydro-2’-deoxyguanosine in DNA.
2002
The aim of ESCODD, a European Commission funded Concerted Action, is to improve the precision and accuracy of methods for measuring 8-oxo-7,8-dihydroguanine (8-oxoGua) or the nucleoside (8-oxodG). On two occasions, participating laboratories received samples of different concentrations of 8-oxodG for analysis. About half the results returned (for 8-oxodG) were within 20% of the median values. Coefficients of variation (for three identical samples) were commonly around 10%. A sample of calf thymus DNA was sent, dry, to all laboratories. Analysis of 8-oxoGua/8-oxodG in this sample was a test of hydrolysis methods. Almost half the reported results were within 20% of the median value, and half …
Oxidative DNA base damage induced by singlet oxygen and photosensitization: recognition by repair endonucleases and mutagenicity.
2000
We have analyzed the recognition by various repair endonucleases of DNA base modifications induced by three oxidants, viz. [4-(tert-butyldioxycarbonyl)benzyl]triethylammonium chloride (BCBT), a photochemical source of tert-butoxyl radicals, disodium salt of 1,4-etheno-2,3-benzodioxin-1,4-dipropanoic acid (NDPO(2)), a chemical source of singlet oxygen, and riboflavin, a type-I photosensitizer. The base modifications induced by BCBT, which were previously shown to be mostly 7,8-dihydro-8-oxoguanine (8-oxoGua) residues, were recognized by Fpg and Ogg1 proteins, but not by endonuclease IIII, Ntg1 and Ntg2 proteins. In the case of singlet oxygen induced damage, 8-oxoGua accounted for only 35% of…
Evolution of gynoecium morphology in Old World Papaveroideae: a combined phylogenetic/ontogenetic approach.
2011
PREMISE OF THE STUDY: The correct assessment of homology is an important prerequisite for reconstructing phylogenetic relationships and character evolution. Old World Papaveroideae (Papaver, Meconopsis, Roemeria, Stylomecon) show substantial diversity in gynoecium and capsule morphology. In particular, capsules can have distinct styles (Meconopsis p.p., Stylomecon) or a sessile stigmatic disc (Papaver). Molecular phylogenetic analyses of Old World Papaveroideae had shown that neither taxa with styles nor those with stigmatic discs represent monophyletic lineages. We here investigate whether either styles or stigmatic discs have arisen repeatedly during the diversification of Old World Papav…
Triterpenoid saponins from the roots of two Gypsophila species.
2013
Two triterpenoid saponins with two known ones have been isolated from the roots of Gypsophila arrostii var. nebulosa, and two new ones from the roots of Gypsophila bicolor. Their structures were established by extensive NMR and mass spectroscopic techniques as 3-O-β-d-galactopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→3)]-β-d-glucuronopyranosylquillaic acid 28-O-β-d-xylopyranosyl-(1→4)-[β-d-glucopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-[β-d-glucopyranosyl-(1→4)]-β-d-fucopyranosyl ester (1), 3-O-β-d-galactopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→3)]-β-d-glucuronopyranosylgypsogenin 28-O-β-d-xylopyranosyl-(1→4)-[β-d-glucopyranosyl-(1→3)]-α-l-rhamnopyranosyl-(1→2)-[β-d-glucopyranosyl-(1→4)]-β-d-fuco…
Organ-specificity and diagnostic value of cell-mediated immunity against a liver-specific membrane protein: Studies in hepatic and non-hepatic diseas…
1975
In chronic active hepatitis (CAH, n=58) 70% of the HBsAg negative and 48% of the HBsAg positive cases showed a CMI against human liver specific proteins (HLPI). Using HBsAg as antigen only 12% of the HBsAg negative and 24% of the HBsAg positive cases gave a CMI response. On the basis of HBsAg and autoantibodies in the serum CAH patients could be divided into 4 subgroups. A close correlation between CMI against HLPI, sex, ANA and HL-A-8 could be detected. In a follow-up study of patients with acute virus B hepatitis (n=62) CMI against HBsAg was detected in 60% of the cases in the acute phase of the disease but in 15% only 3-6 months after the onset of the illness (n=40). In patients who deve…
Dosimetric perturbations of a lead shield for surface and interstitial high-dose-rate brachytherapy.
2014
In surface and interstitial high-dose-rate brachytherapy with either (60)Co, (192)Ir, or (169)Yb sources, some radiosensitive organs near the surface may be exposed to high absorbed doses. This may be reduced by covering the implants with a lead shield on the body surface, which results in dosimetric perturbations. Monte Carlo simulations in Geant4 were performed for the three radionuclides placed at a single dwell position. Four different shield thicknesses (0, 3, 6, and 10 mm) and three different source depths (0, 5, and 10 mm) in water were considered, with the lead shield placed at the phantom surface. Backscatter dose enhancement and transmission data were obtained for the lead shields…
Mannitol in Amanita muscaria – An osmotic blood–brain barrier disruptor enhancing its hallucinogenic action?
2013
Hypothesis have been made that relatively high level of mannitol present in the tissues of fly agaric (Amanita muscaria) enables more efficient transportation of these active substances into the brain and thus enhance their total activity. It may have been supported by the fact that hallucinogenic effect after A. muscaria consumption is greater than after ingestion of an active substance quantity which the eaten fungi dose contain.
Emended descriptions of genera of the family Halobacteriaceae.
2009
The family Halobacteriaceae currently contains 96 species whose names have been validly published, classified in 27 genera (as of September 2008). In recent years, many novel species have been added to the established genera but, in many cases, one or more properties of the novel species do not agree with the published descriptions of the genera. Authors have often failed to provide emended genus descriptions when necessary. Following discussions of the International Committee on Systematics of Prokaryotes Subcommittee on the Taxonomy of Halobacteriaceae, we here propose emended descriptions of the genera Halobacterium, Haloarcula, Halococcus, Haloferax, Halorubrum, Haloterrigena, Natrialba…
Rat and human liver cytosolic epoxide hydrolases: evidence for multiple forms at level of protein and mRNA.
1990
Two forms of human liver cytosolic epoxide hydrolase (cEH) with diagnostic substrate specificity for trans-stilbene oxide (cEHTSO) and cis-stilbene oxide (cEHCSO) have been identified, and cEHCSO was purified to apparent homogeneity. The enzyme had a monomer molecular weight of 49 kDa and an isoelectric point of 9.2. Pure cEHCSO hydrolyzed CSO at a rate of 145 nmole/min/mg. TSO was not metabolized at a detectable level, and like cEHTSO, the enzyme was about three times more active at pH 7.4 than at pH 9.0. Unlike cEHTSO, cEHCSO was efficiently inhibited by 1 mM 1-trichloropropene oxide (90.5%) and 1 mM STO (92%). Similarly, liver cEH purified 541-fold from fenofibrate induced Fischer 344 ra…
Acute lethal toxicity of some pesticides toBrachionus calyciflorus andBrachionus plicatilis
1991
Due to their widespread distribution and toxic nattwe pesticides may have a serious impact on the aquatic environment and exert adverse effects on the associated organisms. Acute bioassay tests have been used to determine the actual impact of various pesticides on aquatic life. Static acute toxicity tests provide rapid and reproductible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a data base for determining relative toxicity to a variety of species.