Vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) is an endothelial cell-specific mitogen that is structurally related to platelet-derived growth factor (PDGF). Vascular endothelial growth factor/vascular permeability factor induces angiogenesis in vivo and may play a critical role in tumor angiogenesis. Using immunohistochemical analysis, the authors demonstrated the presence of VEGF/VPF protein in surgical specimens of glioblastoma multiforme and cultured glioma cells. By means of an enzyme-linked immunosorbent assay (ELISA) of cell supernatants, the authors showed that VEGF/VPF is variably secreted by all nine cultured human malignant glioma cell lines (CH-235MG, D-37MG, D-54MG, D-65MG, U-87MG, U-105MG, U-138MG, U-251MG, U-373MG) and by a single meningioma cell line (CH-157MN). An immunocytochemical survey of these cell lines revealed a cytoplasmic and cell-surface distribution of VEGF/VPF. In the U-105MG glioma cell line, VEGF/VPF secretion was induced with physiological concentrations of epidermal growth factor, PDGF-BB, or basic fibroblast growth factor, but not with PDGF-AA. Moreover, it was observed that activation of convergent growth factor signaling pathways led to increased glioma VEGF secretion. Similar results were obtained using these growth factor combinations in the D-54MG glioma cell line. The data obtained suggest a potential role for VEGF/VPF in tumor hypervascularity and peritumoral edema. These observations may lead to development of new therapeutic strategies.
These data suggest that meningioma-associated edema may be a result of the capacity of meningioma cells to produce VPF/VEGF locally, leading to increased tumor neovascularization and enhanced vascular permeability.
A total of 71 fusidic acid-resistant Staphylococcus aureus (45 methicillin-resistant and 26 methicillin-susceptible) isolates were examined for the presence of resistance determinants. Among 45 fusidic acid-resistant methicillin-resistant S. aureus (MRSA), isolates, 38 (84%) had fusA mutations conferring high-level resistance to fusidic acid (the MIC was >128 g/ml for 22/38), none had fusB, and 7 (16%) had fusC. For 26 fusidic acid-resistant methicillin-susceptible S. aureus (MSSA), only 3 possessed fusA mutations, but 15 (58%) had fusB and 8 (31%) had fusC. Low-level resistance to fusidic acid (MICs < 32 g/ml) was found in most fusB-or fusC-positive isolates. For 41 isolates (38 MRSA and 3 MSSA), with fusA mutations, a total of 21 amino acid substitutions in EF-G (fusA gene) were detected, of which R76C, E444K, E444V, C473S, P478S, and M651I were identified for the first time. The nucleotide sequencing of fusB and flanking regions in an MSSA isolate revealed the structure of partial IS257-aj1-LP-fusB-aj2-aj3-IS257-partial blaZ, which is identical to the corresponding region in pUB101, and the rest of fusB-carrying MSSA isolates also show similar structures. On the basis of spa and staphylococcal cassette chromosome mec element (SCCmec) typing, two major genotypes, spa type t037-SCCmec type III (t037-III; 28/45; 62%) and t002-II (13/45; 29%), were predominant among 45 MRSA isolates. By pulsed-field gel electrophoresis analysis, 45 MRSA isolates were divided into 12 clusters, while 26 MSSA isolates were divided into 15 clusters. Taken together, the distribution of fusidic acid resistance determinants (fusA mutations, fusB, and fusC) was quite different between MRSA and MSSA groups.
The full-length sequences of the groESL genes (also known as cpn10/60) of Streptococcus anginosus, Streptococcus constellatus, Streptococcus gordonii, and Streptococcus sanguis and the near full-length sequence of the groESL genes of Streptococcus intermedius, Streptococcus bovis, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, and Streptococcus salivarius were determined. The lengths of the groES genes from the 10 species listed above ranged from 282 to 288 bp, and the full-length sequences of groEL determined for 4 species (S. anginosus, S. constellatus, S. gordonii, and S. sanguis) revealed that each was 1,623 bp. The intergenic region (spacer) between the groES and groEL genes varies in size (15 to 111 bp) and sequence between species. The variation of the groES sequences among the species tested was greater (62.1 to 95.1% nucleotide sequence identities) than that of the groEL sequences (77.2 to 95.2% nucleotide sequence identities). Phylogenetic analysis of the groES and groEL genes yielded evolutionary trees similar to the tree constructed by use of the 16S rRNA gene. The intraspecies variation of the spacer was minimal for clinical isolates of some species. The groESL sequence data provide an additional parameter for identification of viridans group streptococcal species.Viridans group streptococci (VGS) are the most common etiologic agents in subacute infective endocarditis and are known to be capable of causing many serious pyogenic infections (1,4,14). Since the clinical significance of VGS may differ between species, it is important to identify the individual species associated with diseases and to recognize their pathogenic traits (14). Moreover, increases in rates of antimicrobial resistance have been noted among VGS (25). The difference in susceptibilities between species of VGS indicates the importance of accurate identification. At present, the species of VGS can be divided into five major groups according to their 16S rRNA sequences (15). These are (i) the anginosus group (also called the milleri group), which includes At present, species identification of VGS is based on physiological and biochemical characteristics determined by conventional methods, which are time-consuming (6). Many clinical laboratories rely on manual or automated phenotypic test systems. However, there have been variations among physiological reactions within the same species, and misidentification has occurred, particularly for some species. S. mutans strains and strains of the anginosus and mitis groups are the most problematic (12, 29). Differentiation of species within the same group is often difficult (6, 27). Another approach to species identification may be the use of molecular methods. Several DNA-based techniques have been developed for the identification of VGS to the species level (3,7,8,13,16,21,23,24,28). The target genes have included 16S rRNA genes, the tRNA gene intergenic spacer, 16S-23S rRNA spacers, the gene for D-alanine-D-alanine ligase, and the gene for manganese-dependent superoxide ...
The staphylococcal chromosome cassette (SCC)mec types of 382 hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) isolates in Taiwan were analysed over a 7-year period (1999-2005). There was an abrupt increase in SCCmec type IV in HA-MRSA during 2005. The molecular epidemiology of a subset (n = 69) of HA-MRSA isolates with SCCmec types III, IV or V was characterised and compared with that of community-acquired MRSA (CA-MRSA) (n = 26, collected during 2005). Pulsed-field gel electrophoresis revealed three major pulsotypes (A, B and C) and 15 minor clones. Pulsotypes B and C, which contained isolates carrying SCCmec types IV and V, respectively, included both CA-MRSA and HA-MRSA isolates. Among 24 toxin genes analysed, five genes had significant differential distribution between CA-MRSA and SCCmec type III HA-MRSA. Furthermore, among SCCmec type IV isolates, the seb gene was detected more commonly in HA-MRSA. Analysis of representative members of the three major pulsotypes by multilocus sequence typing revealed two sequence types (STs), namely ST239 (SCCmecIII) and ST59 (SCCmecIV or SCCmecV). This suggests that ST59:SCCmecIV, which is usually community-acquired, has become an important nosocomial pathogen in the hospital studied.
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