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51.
The photosensitizing properties of p-nitroacetophenone (PNAP), a well-known radiosensitizer, have been studied in near UV region. The mechanism of PNAP photosensitization has been investigated by testing the efficiency of singlet oxygen production using photooxidation of 2,2,6,6-tetramethylpiperidine (TEMP) and photodegradation of guanosine. In both the cases, the enhancement effect of deuterated solvents has been observed. Results of these experiments suggest the significant role of type II mechanisms in PNAP photosensitization. 相似文献
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One hundred and ninety-five teeth in 35 patients with periodontitis who had received both endodontic and periodontal treatment were evaluated 9 years after endodontic treatment and 8 years after periodontal treatment. Some 91.4% of cases were well maintained and 8.6% showed a deterioration in their periodontal condition. Twelve of the 195 teeth with endodontic treatment were lost, eight for periodontal reasons, three as a result of fracture and one because of caries, and the periodontal condition of 10 teeth had worsened. An apical lesion formed on one tooth. The results indicate that the risk of endodontic failure in this group of 195 teeth is very low, and that there is little risk of tooth loss for periodontal reasons, provided that the patients receive supportive periodontal treatment. 相似文献
54.
Perturbation of adhesion mediated by cadherins was achieved by over-expressing truncated forms of E- and EP-cadherins (in which the extracellular domain was deleted) in different blastomeres of stage 6 Xenopus laevis embryos. Injections of mRNA encoding truncated E- and EP-cadherins into A1A2 blastomeres resulted in inhibition of cell adhesion and, at later stages, in morphogenetic defects in the anterior neural tissues to which they mainly contribute. In addition, truncated EP-cadherin mRNA produced a duplication of the dorso-posterior axis in a significant number of cases. The expression of truncated E- and EP-cadherins in blastomeres involved in gastrulation and neural induction (B1B2 and C1), led to the duplication of the dorso-posterior axis as well as to defects in anterior structures. Morphogenetic defects obtained with truncated EP-cadherin were more severe than those induced with truncated E-cadherin. Cells derived from blastomeres injected with truncated EP-cadherin mRNA, dispersed more readily at the blastula and gastrula stages than the cells derived from the blastomeres expressing truncated E-cadherin. Presumptive mesodermal cells expressing truncated cadherins did not engage in coherent directional migration. The alteration of cadherin-mediated cell adhesion led directly to the perturbation of the convergent-extension movements during gastrulation as shown in the animal cap assays and indirectly to perturbation of neural induction. Although the cytoplasmic domains of type I cadherins share a high degree of sequence identity, the over-expression of their cytoplasmic domains induces a distinct pattern of perturbations, strongly suggesting that in vivo, each cadherin may transduce a specific adhesive signal. These graded perturbations may in part result from the relative ability of each cadherin cytoplasmic domain to titer the beta-catenin. 相似文献
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K Jaton-Ogay S Paris M Huerre M Quadroni R Falchetto G Togni JP Latgé M Monod 《Canadian Metallurgical Quarterly》1994,14(5):917-928
Aspergillus fumigatus secretes a serine alkaline protease (ALP) and a metalloprotease (MEP) when the fungus is cultivated in the presence of collagen as sole nitrogen and carbon source. The gene encoding ALP was isolated and characterized previously. We report here the cloning and the sequencing of the gene encoding MEP. Genomic and cDNA clones were isolated from A. fumigatus libraries using synthetic oligonucleotides as probes. Stretches of the deduced amino acid sequence were found to be in agreement with the N-terminal amino acid sequence of MEP and with internal peptide sequences. The amino acid sequence of the enzyme contains a putative active-site sequence HEYTH homologous to the active site of other bacterial and eukaryotic zinc metalloproteases. Sequence analysis reveals that MEP has a pre-proregion consisting of 245 amino acid residues preceding the 388 amino acid residues of the mature region (molecular mass of 42 kDa). An alp mep mutant, deficient in proteolytic activity at neutral pH in vitro, was constructed and tested for pathogenicity in a murine model. No difference in pathogenicity was observed between the wild-type strain and the alp mep double mutant, suggesting that ALP and MEP are not essential for the invasion of the lung tissues by A. fumigatus. 相似文献
56.
The author describes a patient who has a successful coronary artery bypass. Six weeks later, after a physical examination of the chest, she had unbearable sharp, stabbing pain around the incision which was not responding to nerve blocks, analgesics, nonsteroidal anti inflammatory agents, and epidural blocks. The pain was responsive to mexilitine and disappeared after three weeks of treatment. 相似文献
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