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21.
Cucinotta V Giuffrida A La Mendola D Maccarrone G Puglisi A Rizzarelli E Vecchio G 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,800(1-2):127-133
The systems that the 3-amino derivative of beta-cyclodextrin (CD3NH2) forms with the proton, the copper(II) ion and each of the enantiomers of certain amino acids (alanine, phenylalanine, tyrosine and tryptophan) were investigated. The enantioselectivity shown by the potentiometric measurements carried out on the phenylalanine ternary systems was exploited in capillary electrophoresis by ligand exchange capillary electrophoresis (LECE) to obtain the separation of phenylalanine racemate. The tyrosine racemate was also separated by LECE. The comparison between thermodynamic and capillary electrophoresis (CE) results is discussed, in order to get a better insight into the separation mechanism. 相似文献
22.
The Cyanidiales is a group of asexual, unicellular red algae, which thrive in acidic and high temperature conditions around hot springs. These unicellular taxa have a relatively simple morphology and are currently classified into three genera, Cyanidium, Cyanidioschyzon and Galdieria. Little is known, however, about the biodiversity of Cyanidiales, their population structure and their phylogenetic relationships. Here we used a taxonomically broadly sampled three-gene data set of plastid sequences to infer a robust phylogenetic framework for the Cyanidiales. The phylogenetic analyses support the existence of at least four distinct Cyanidiales lineages: the Galdieria spp. lineage (excluding Galdieria maxima), the Cyanidium caldarium lineage, a novel monophyletic lineage of mesophilic Cyanidium spp. and the Cyanidioschyzon merolae plus Galdieria maxima lineage. Our analyses do not support the notion of a mesophilic ancestry of the Cyanidiales and suggest that these algae were ancestrally thermo-acidotolerant. We also used environmental polymerase chain reaction (PCR) for the rbcL gene to sample Cyanidiales biodiversity at five ecologically distinct sites at Pisciarelli in the Phlegrean Fields in Italy. This analysis showed a high level of sequence divergence among Cyanidiales species and the partitioning of taxa based on environmental conditions. Our research revealed an unexpected level of genetic diversity among Cyanidiales that revises current thinking about the phylogeny and biodiversity of this group. We predict that future environmental PCR studies will significantly augment known biodiversity that we have discovered and demonstrate the Cyanidiales to be a species-rich branch of red algal evolution. 相似文献
23.
The use of nuclear and mitochondrial single nucleotide polymorphisms to identify cryptic species 总被引:3,自引:0,他引:3
There is growing interest in the use of single nucleotide polymorphisms for evolutionary and population genetics. We tested the efficacy of one of the available single nucleotide polymorphism techniques, single-base extension, in distinguishing four cryptic species of Microtus. Sequence data were available for these species at nuclear and mitochondrial loci and their identity could be independently confirmed using karyotypes. We found that the development and optimization of single nucleotide polymorphisms required extensive effort, and that the method accurately identified the correct nucleotide at single nucleotide polymorphism sites approximately 90% of the time at the conserved nuclear locus. Correct identification rates were much lower at the highly variable mitochondrial locus. 相似文献
24.
Catelani G Corsaro A D'Andrea F Mariani M Pistarà V Vittorino E 《Carbohydrate research》2003,338(22):2349-2358
2,6-di-O-benzyl- (9), 2-O-benzyl-3,4-O-isopropylidene- (19), and 2-O-benzyl-6-O-m-chlorobenzoyl-L-arabino-hexos-5-ulose (20) have been prepared using 4'-deoxy-4'-eno- and 6'-deoxy-5'-eno lactose dimethyl acetal derivatives 7 and 14 as key intermediates. The synthesis of enol ethers 7 and 14 has been performed with good yields by base-promoted elimination of acetone or p-toluenesulfonic acid from 2',6'-di-O-benzyl-, and 6'-O-p-toluenesulfonyl-2,3:5,6:3',4'-tri-O-isopropylidenelactose dimethyl acetal, respectively. The epoxidation with MCPBA of 7 and 14 in methanol or dichloromethane furnishes C-5'-methoxy and C-5'-m-chlorobenzoyloxy derivatives, easily transformed with good yields into L-arabino 5-ketoaldohexoses 9, 19 and 20. 相似文献
25.
BACKGROUND: Macrofollicular encapsulated papillary carcinoma (MEPC) is a variant of papillary carcinoma with a favorable clinical course. Its characteristic histologic pattern could be mistaken for that of an adenoma or hyperplastic nodule. Fine needle aspiration of this neoplasm may not show the particular nuclear features of papillary carcinoma, so the cytologic diagnosis may be benign. CASE REPORTS: Three paradigmatic cases of MEPC with different histologic patterns, diagnosed as a follicular neoplasm using fine needle aspiration biopsy (FNAB) are described. Preoperative cytology showed scattered clusters of thyrocytes with prominent nuclear pleomorphism and irregularities and focal oxyphilic changes mixed with colloid and aggregates of typical thyrocytes. The histologic picture exhibits small, neoplastic foci showing a microfollicular structure within an encapsulated neoplasm with a macrofollicular pattern. In microfollicular areas obvious nuclear pseudoinclusions were seldom observed. CONCLUSION: MEPC represents a challenging tumor subtype that infrequently shows the pathognomonic cytologic characteristics of papillary carcinoma, and therefore it is much more difficult to diagnose with a FNAB. Nuclear pleomorphism and irregularity of the nuclear membrane of thyrocytes are clues to this variant, although in some cases a clear-cut preoperative diagnosis cannot be made. 相似文献
26.
Lucarelli M Borrelli V Fiori A Cucina A Granata F Potenza RL Scarpa S Cavallaro A Strom R 《FEBS letters》2002,517(1-3):19-23
Based on the functional characterization of sucrose biosynthesis related protiens[SBP: sucrose-phosphate synthase (SPS), sucrose-phosphate phosphatase (SPP), and sucrose synthase (SuS)] in Anabaena sp. PCC7120 and sequence analysis, we have shown that SBP are restricted to cyanobacterium species and plants, and that they are multidomain proteins with modular architecture. Anabaena SPS, a minimal catalytic SPS unit, defines a glucosyltransferase domain present in all SPSs and SuSs. Similarly, Anabaena SPP defines a phosphohydrolase domain characteristic of all SPPs and some SPSs. Phylogenetic analysis points towards the evolution of modern cyanobacterial and plant SBP from a bidomainal common ancestral SPS-like gene. 相似文献
27.
In the immunocompetent host, Mycobacterium avium is responsible for chronic localized pulmonary disease, which is characterized by the presence of increased numbers of activated T cells and macrophages in the lungs. M. avium organisms as well as sonic extracts of M. avium were found to act as chemoattractants for THP-1 cells as well as monocytes, monocyte-derived macrophages and alveolar macrophages obtained from normal human donors in an in vitro chemotaxis assay, where a significantly higher number of cells were found in wells containing M. avium compared to control wells. Proteolytic treatment of M. avium sonicate resulted in significant loss (50%) of chemotactic activity. Monoclonal antibodies against recombinant human monocyte chemoattractant protein-1 (MCP-1) were found to cross-react with a 34-kDa protein of M. avium sonicate on Western blot and inhibit M. avium sonicate-mediated chemotaxis of THP-1 cells (47%). These data suggest the presence of an 'MCP-1 like' molecule on M. avium. Recruitment of host immune regulatory cells to the site of infection by pathogens may be involved in generating a local immune response or may be a bacterial strategy for survival within the host by recruiting the cells that they infect, i.e. macrophages. 相似文献
28.
The well-known Fisher type selection-mutation model is studied from the point of view of mathematical systems theory. Mutation rates are considered as control functions. Based on a general sufficient condition for local controllability of non-linear systems with invariant manifold, a method is proposed to guarantee the controllability of the considered population into a polymorphic equilibrium. 相似文献
29.
Oxidative damage of the gastric mucosa in Helicobacter pylori positive chronic atrophic and nonatrophic gastritis, before and after eradication 总被引:3,自引:0,他引:3
Iacopini F Consolazio A Bosco D Marcheggiano A Bella A Pica R Paoluzi OA Crispino P Rivera M Mottolese M Nardi F Paoluzi P 《Helicobacter》2003,8(5):503-512
Background. Helicobacter pylori is the main cause of gastritis and a primary carcinogen. The aim of this study was to assess oxidative damage in mucosal compartments of gastric mucosa in H. pylori positive and negative atrophic and nonatrophic gastritis. Materials and methods. Five groups of 10 patients each were identified according to H. pylori positive or negative chronic atrophic (Hp‐CAG and CAG, respectively) and nonatrophic gastritis (Hp‐CG and CG, respectively), and H. pylori negative normal mucosa (controls). Oxidative damage was evaluated by nitrotyrosine immunohistochemistry in the whole mucosa and in each compartment at baseline and at 2 and 12 months after eradication. Types of intestinal metaplasia were classified by histochemistry. Results. Total nitrotyrosine levels appeared significantly higher in H. pylori positive than in negative patients, and in Hp‐CAG than in Hp‐CG (p < .001); no differences were found between H. pylori negative gastritis and normal mucosa. Nitrotyrosine were found in foveolae and intestinal metaplasia only in Hp‐CAG. At 12 months after H. pylori eradication, total nitrotyrosine levels showed a trend toward a decrease in Hp‐CG and decreased significantly in Hp‐CAG (p = .002), disappearing from the foveolae (p = .002), but remaining unchanged in intestinal metaplasia. Type I and II of intestinal metaplasia were present with the same prevalence in Hp‐CAG and CAG, and did not change after H. pylori eradication. Conclusions. Oxidative damage of the gastric mucosa increases from Hp‐CG to Hp‐CAG, involving the foveolae and intestinal metaplasia. H. pylori eradication induces a complete healing of foveolae but not of intestinal metaplasia, reducing the overall oxidative damage in the mucosa. 相似文献
30.
Iannello S Cavaleri A Milazzo P Cantarella S Belfiore F 《MedGenMed : Medscape general medicine》2003,5(3):20
The authors recently reported the occurrence of low fasting serum triglyceride (TG) and high free fatty acid (FFA) levels in idiopathic pulmonary fibrosis. TG estimation in diverse groups of patients with autoimmune disease or hyperactive immune response confirmed the occurrence of a similar decrease of TG. In some patients, serum FFA level was also evaluated. TG value in lean and obese patients was compared with that in lean (n = 108) and obese (n = 208) control subjects without autoimmune disease. In patients affected by autoimmune chronic thyroiditis with enhanced concentration of antithyroglobulin antibodies and without thyroidal failure (n = 24), lean and obese patients had reduced TG (-69/%, P < .01 and -52%, P < .0001, respectively). Both lean and obese patients affected by chronic active B or C hepatitis (n = 26), with autoantibodies and without signs of hepatic insufficiency or cirrhosis, presented reduced TG (-57%, P < .01 and -61%, P < .001, respectively). A marked TG decrease (-73%, P < .001) was observed in the lean patients affected by lupus-like syndrome (n = 7). The lean and obese patients with systemic lupus erythematosus or rheumatoid arthritis (n = 11) showed TG decrease (-66%, P < .01 and -55%, P < .05, respectively). In patients affected by anamnestic allergy or atopic dermatitis/asthma (n = 66), both lean and obese, TGs were reduced (-67%, P < .0001 and -62%, P < .001, respectively). In isolated cases of diverse autoimmune diseases (scleroderma, APECED [autoimmune polyendocrinopathy, candidiasis, and ectodermal dystrophy], urticaria or urticarial vasculitis, Reiter or Sjogren syndromes, ulcerative colitis or Crohn's disease, multiple sclerosis or Guillain-Barré syndrome) (n = 14), decreased TG was also observed both in the lean and obese subjects (-59%, P < .01 and -57%, P < .01, respectively). Concerning FFA (n = 69), value in lean patients (n = 22) vs that in lean controls (n = 18) was increased (520 +/- 31 vs 299 +/- 30 mcEq/L, +74%, P < .001), whereas value in obese patients (n = 18) vs that in obese control subjects (n = 11) was decreased (542 +/- 34 vs 774 +/- 62, -30%, P < .01). This opposite behavior of FFA in lean and obese patients needs to be confirmed. Data in this study seem to indicate that low TG value may be a precocious marker of autoimmunity or immune system hyperreactivity. 相似文献