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991.
Nobre Mde O Antunes Tde A de Faria RO Cleff MB Fernandes CG Muschner AC Meireles MC Ferreiro L 《Mycopathologia》2005,160(1):43-49
Sporotrichosis is a chronic subcutaneous mycosis caused by Sporothrix schenckii. This work aimed to evaluate the virulence of two different isolates of S. schenckii from cutaneous (CUT) and systemic (SYS) forms of feline sporotrichosis. A standard inoculum with 2 × 103 yeast cells/ml was prepared from each of the isolates. The experimental infection was carried out with 0.1 ml of the inoculum from both isolates and then injected in the paw pads of Swiss albino mice of groups CUT and SYS. The clinical evolution of the disease and the diameter of the lesion at the inoculated sites were evaluated during nine weeks. Four necropsies were done to collect material from the lesions (p < 0.01). Group CUT demonstrated a more evident clinical evolution of the disease from week two to week five; large lesions in the paw pad on week four (p < 0.01); and a higher incidence of lesions in other parts of the body (p < 0.01) than group SYS (p < 0.01). S. schenckii was isolated from the inoculated site in groups SYS and CUT until days 30 and 45, respectively. Granulomas with yeast cells usually localized in the central area were observed in histopathology sections on days 15 and 30 post-inoculations. Those yeast cells decreased on day 45 being absent on day 62 when tissue repair initiated. The results showed that distinct clinical isolates of S. schenckii cause significant differences in the clinical evolution of sporotrichosis. 相似文献
992.
Colonization of rat thymic anlage by the first wave of hemopoietic precursor cells (HPc) was investigated by means of transmission
electron microscopy and immunocytochemistry. HPc began migration into the thymic anlage between 13 and 13.5 gestation days
(GD), terminated colonization at about GD 16, and migrated sequentially through the two compartments of the thymic anlage
under the control of typical populations of stromal cells. First, HPc migrated through the external compartment of the perithymic
mesenchyme, tightly interconnected with fibroblasts. The type of junctions between the cells indicated that the fibroblasts
played a role in the control of HPc trafficking and in their entrance to the epithelial compartment. The second stage of colonization
was initiated by the entrance of HPc to the epithelial compartment and their interaction with thymic epithelial cells (TECs).
Based on morphological criteria, two populations of HPc were distinguished that colonized the anlage at various stages of
its development. The predominant population with ultrastructural traits common to thymocytes “homed” into the epithelial type
primordium. A small number of HPc, identified by protein S-100 expression and by Birbeck’s granules as precursors of dendritic
cells, colonized lymphoepithelial anlage in which subsets of cortical and medullary TECs could be distinguished. Thymocyte
migration and their reciprocal interactions with cortical TECs differed from the trafficking of dendritic cells toward the
medulla. The results demonstrated the influence of maturing thymocytes on the development of cortical epithelial cells and
the dynamic organization of the medullary microenvironment with direct involvement of dendritic cells.
This study was supported by UMS grant 501-2-0003404. 相似文献
993.
Martins LC Corvelo TC Demachki S Araujo MT Assumpção MB Vilar SC Freitas FB Barbosa HP Fecury AA do Amaral RK Dos Santos SE 《Memórias do Instituto Oswaldo Cruz》2005,100(8):875-881
We have examined the prevalence of gene cagA and vacA alleles in 129 patients, 69 with gastritis and 60 with peptic ulcer diseases from North Brazil and their relation with histopathological data. vacA and cagA genotype were determined by polymerase chain reaction. Hematoxylin-eosin staining was used for histological diagnosis. 96.6% of the patients were colonized by Helicobacter pylori strains harboring single vacA genotype (nont-mixed infection). Among them, 11.8% had subtype s1a, 67.8% had subtype s1b, and 17% subtype s2. In regard to the middle region analysis, m1 alleles were found in 75.4% and m2 in 21.2% of patients. The cagA gene was detected in 78% patients infected with H. pylori and was associated with the s1-m1 vacA genotype. The H. pylori strains, vacA s1b m1/cagA-positive, were associated with increased risk of peptic ulcer disease and higher amounts of lymphocytic and neutrophilic infiltrates and the presence of intestinal metaplasia. These findings show that cagA and vacA genotyping may have clinical relevance in Brazil. 相似文献
994.
995.
Effects of sex, age, body mass, and capturing method on hematologic values of brown bears in Croatia
Kusak J Rafaj RB Zvorc Z Huber D Forsek J Bedrica L Mrljak V 《Journal of wildlife diseases》2005,41(4):843-847
Effects of various intrinsic and extrinsic factors on 17 hematologic values from 56 brown bears (Ursus arctos) sampled in Croatia from 1981 to 2005 were evaluated. Differences between female and male bears were detected for number of erythrocytes, sedimentation rate after 30 min, and number of leukocytes and segmented neutrophils. Significant differences between free-living vs. captive and snared vs. not snared bears were detected for the same three parameters: leukocytes, segmented neutrophils, and eosinophils. It was concluded that the physical exertion of bears snared by leg, rather than their free-living status, influenced differences of results among these groups. The obtained mean values are useful reference values for the species. 相似文献
996.
Using cointegrate formation, we constructed a basic replicon of the megaplasmid/mini-chromosome pTAV3 of Paracoccus versutus UW1. It is composed of two adjacent modules, responsible for plasmid replication (rep) and partitioning (par). Functional analysis of the par region identified a determinant of incompatibility (inc2), whose presence is crucial for proper partitioning (the partitioning site). Database searches revealed that the only known replicon with significant homology to that of pTAV3 is encoded by the chromosome cII of Rhodobacter sphaeroides 2.4.1. Incompatibility studies showed that closely related basic replicons are also encoded by megaplasmids (above 400 kb) harbored by four strains of P. pantotrophus. Basic replicons of the pTAV3-type are able to maintain large bacterial genomes, therefore they appear to be good candidates for the construction of vectors specific for Alphaproteobacteria. 相似文献
997.
Staphostatins are the endogenous, highly specific inhibitors of staphopains, the major secreted cysteine proteases from Staphylococcus aureus. We have previously shown that staphostatins A and B are competitive, active site-directed inhibitors that span the active site clefts of their target proteases in the same orientation as substrates. We now report the crystal structure of staphostatin B in complex with wild-type staphopain B at 1.9 A resolution. In the complex structure, the catalytic residues are found in exactly the positions that would be expected for uncomplexed papain-type proteases. There is robust, continuous density for the staphostatin B binding loop and no indication for cleavage of the peptide bond that comes closest to the active site cysteine of staphopain B. The carbonyl carbon atom C of this peptide bond is 4.1 A away from the active site cysteine sulfur Sgamma atom. The carbonyl oxygen atom O of this peptide bond points away from the putative oxyanion hole and lies almost on a line from the Sgamma atom to the C atom. The arrangement is strikingly similar to the "ionmolecule" arrangement for the complex of papain-type enzymes with their substrates but differs significantly from the arrangement conventionally assumed for the Michaelis complex of papain-type enzymes with their substrates and also from the arrangement that is crystallographically observed for complexes of standard mechanism inhibitors and their target serine proteases. 相似文献
998.
Gajecka M Rydzanicz M Jaskula-Sztul R Kujawski M Szyfter W Szyfter K 《Mutation research》2005,574(1-2):112-123
Polymorphisms in the selected genes controlling carcinogen metabolism (CYP1A1, CYP2D6, CYP2E1, NAT2, GSTM1, GSTT1) considered separately or in different combinations, were investigated for an association with tobacco smoke-associated squamous cell carcinoma (SCC) of the larynx. The case-control study was performed in 289 patients with laryngeal SCC and in 316 cancer-free controls; all were Caucasian males from the same region of Poland and current tobacco smokers. The DNA samples were genotyped using PCR-RFLP and multiplex PCR. The variants' frequencies in both groups were compared; odds ratios and their 95% confidence intervals were calculated by logistic regression analyses. The CYP1A1*1/*4, CYP2D6*4/*4, NAT2*4/*6A genotypes, as well as the CYP1A1*4, CYP2D6*4 and NAT2*4 alleles, were found at significantly higher frequencies in cases than in controls indicating their role as "risk-elevating" factors in laryngeal SCC. Combined genotypes, characterized by the presence of the "risk-elevating" variants at more than one locus, often occurred together with the null variant of the GSTM1 gene and homozygous XPD A/A (Lys751Gln, A35931C) genotype. Furthermore, we identified some "protective" variants, found more frequently in controls than in cases, i.e. the NAT2*6A/*6A and NAT2*5B/*6A genotypes. A distribution of "risk" or "protection" genotypes/alleles seems to be connected with age as an occurrence or risk genes was more frequent in the group of "young" cases (< or = 49 years). Accumulation of certain alleles or genotypes of the CYP1A1, NAT2, GSTM1 and XPD seems to be associated with either increased or decreased risk to develop laryngeal SCC. Therefore, polymorphisms in these genes may play a role in the laryngeal cancer etiology. 相似文献
999.
Leite AC Vieira RF de M Moreira DR Brondani DJ Srivastava RM da Silva VF de Morais Júnior MA 《Mutation research》2005,588(2):166-171
Compounds derived from 1,2,4-oxadiazole have being reported for their anti-inflammatory activity. However, those compounds should be devoid of any genotoxic side effect. In this work, the genotoxic activity of peptidomimetic moiety-containing 1,2,4-oxadiazoles derivatives was tested based on the Ames and SOS Chromotest. The results showed no mutagenic activity on the Ames test for 3-[3-phenyl-1,2,4-oxadiazol-5-yl] propionic acid (POPA) parental drug, but a weak SOS response induction on Chromotest. The chemical modifications reduced that response to a non-significative level, with l-phenylalanine peptidomimetic derivative being showing the lowest induction response. The results pointed out for the effectiveness of promoting chemical modifications of biological active compounds to increase its mode of action, showed in previous work, without increasing and even decreasing its DNA damage effect. 相似文献
1000.
Yeast as a biosensor for antioxidants: simple growth tests employing a Saccharomyces cerevisiae mutant defective in superoxide dismutase 总被引:1,自引:0,他引:1
Zyracka E Zadrag R Kozioł S Krzepiłko A Bartosz G Biliński T 《Acta biochimica Polonica》2005,52(3):679-684
Mutants of Saccharomyces cerevisiae devoid of Cu,Zn-superoxide dismutase are hypersensitive to a range of oxidants, hyperbaric oxygen and hyperosmotic media, show lysine and methionine auxotrophy when grown under the atmosphere of air and have a shortened replicative life span when compared to the wild-type strain. Ascorbate and other antioxidants can ameliorate these defects, which may be a basis of simple tests sensing the presence of antioxidants. In particular, tests of growth on solid medium (colony formation) in the absence of methionine and/or lysine, or in the presence of 0.8 M NaCl can be useful for detection and semiquantitative estimation of compounds of antioxidant properties. Hypoxic atmosphere was found to increase the sensitivity of detection of antioxidants. The test of abolishment of lysine auxotrophy showed a concentration dependence of the antioxidant effects of cysteine and N-acetylcysteine which, however, lost their protective action at high concentration, in contrast to glutathione which was effective also at higher concentrations. 相似文献