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91.
92.
Schleiermacher G Raynal V Janoueix-Lerosey I Combaret V Aurias A Delattre O 《Genes, chromosomes & cancer》2004,39(2):143-150
In neuroblastoma, the most frequent genetic alteration is gain of chromosome arm 17q, which arises from unbalanced translocations. To document these genetic events more precisely, we performed an extensive study of chromosome 17 breakpoints in 27 neuroblastoma cell lines by using a combination of fluorescence in situ hybridization mapping with BAC/PAC clones and allele analysis with polymorphic markers. All cases exhibited one or more unbalanced chromosome 17 translocations, and 15 distinct breakpoint regions could be mapped. This high variability indicates that gene fusion or disruption events are extremely unlikely to account for the underlying oncogenic role of these translocations. However, breakpoints were not randomly distributed, most of them mapping to the proximal part of 17q. As a result of translocations, all cell lines but one exhibited gain of the 53.5 Mb-->qter fragment, bordered proximally by the clone CTC-462L7. The most telomeric breakpoint, flanked by the clone RP11-443M10, defined the 70.9 Mb-->qter fragment as a region of additional gain. In addition to chromosome gains, loss of heterozygosity for the short arm of chromosome 17 was observed in close to half the cases. It was either related to a chromosome 17 monosomy or to a uniparental isodisomy. Finally, in cases with a single normal chromosome 17, we show that the parental origin of the translocated chromosome 17 can be either distinct or identical to that of the normal chromosome. Similarly, multiple translocations within the same cell line can either involve the same or different chromosome 17 homologues, indicating the likely absence of parental origin bias in the generation of these alterations. 相似文献
93.
Langerhans dendritic cells are antigen presenting cells (APC) that reside within the epidermis and are capable of stimulating naive T cells. Reciprocally, lymphocytes may play a role in Langerhans cells (LC) differentiation. Our results show that the differentiation of skin LC is unaffected in the absence of lymphocytes and/or signaling through the common cytokine receptor gamma chain (gammac) required for IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21 signaling. Migration of LC and other dendritic cells (DC) from the skin to the draining lymph nodes (LNs) after FITC skin sensitization, is unaffected in the absence of lymphocytes or CD40. FITC+ LC/DC sorted from the LNs of lymphoid deficient or control mice stimulated naive T cells with similar efficiency. However, while the absence of lymphocytes did not appear to affect the phenotype or number of emigrating LN DC/LC, their persistence in the LN appears to depend on alphabeta T cells. Thus, DC are strikingly reduced in numbers in the peripheral LNs of T-cell deficient mice. Finally, CD8alpha expression on skin emigrants was low and dependent on the presence of CD8+ lymphocytes, while spleen CD8+ DC were present in the absence of lymphocytes. We conclude that the presence of T cells is not required for the differentiation and migration of resident skin DC but is critical for the maintenance of DC and LC migrating into the LNs. 相似文献
94.
Presentation of antigen to suppressor cells by a dimethylbenz (a) anthracene-resistant, Ia-positive, Thy-1-negative, I-J-restricted epidermal cell 总被引:1,自引:0,他引:1
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The epidermal layer of the skin contains class II major histocompatibility (MHC)-positive antigen-presenting cells (APC), the most well characterized population being Langerhans' cells (LC). The chemical carcinogen 7,12 dimethylbenz (a) anthracene (DMBA) depletes about two-thirds of these cells from murine epidermis, and contact sensitizers applied to DMBA-treated skin induce specific immunological tolerance. This tolerance results from epidermal cells migrating to local lymph nodes within 3-6 hr after contact with antigen where they present the antigen to suppressor cells. Here we demonstrate that this epidermal cell which activates suppressor cells is a class II MHC-positive. Thy-1-negative, I-J-restricted APC. Hence at least two types of class II MHC-positive epidermal cells migrate to local lymph nodes and present antigen to lymphocytes; LC, which are sensitive to the effects of DMBA and activate helper lymphocytes, and another, which is resistant to DMBA and activates suppressor cells in an I-J-restricted manner. During the early stages of carcinogenesis any antigen present in the epidermis would be presented only by the cells which activate suppressor lymphocytes, resulting in tolerance induction. This may enable neoplastic cells to avoid the initiation of anti-tumour immunity. 相似文献
95.
Structure of four amplified DNA novel joints 总被引:8,自引:0,他引:8
Edith Legouy Nicole Fossar Guy Lhomond Olivier Brison 《Somatic Cell and Molecular Genetics》1989,15(4):309-320
The structures of four novel joints present in the amplified DNA of a Syrian hamster cell line highly resistant to N-(phosphonacetyl)-l-aspartate were analyzed. Novel joints J1, J2, and J4 were formed by recombination between two regions of wild-type DNA, whereas joint J3 is the end point of an inverted duplication. A fraction of the J3 copies displays a cruciform structure in the purified genomic DNA. The formation of J1 and J2 apparently involved a simple breakage and joining of the two wild-type sequences, whereas extra nucleotides are present at the junction point of J3 and J4. The two regions of the wild-type DNA which have recombined to form J1, J2, and J4 show few sequence similarities, indicating that these joints probably resulted from nonhomologous recombination. AT-rich regions are present in the vicinity of the breakpoint for the four joints and eight of 10 crossover points could be associated with putative topoisomerase I cleavage sites. Our results indicate that different types of novel joints are present in the amplified DNA of this cell line, which was isolated after several steps of selection. 相似文献
96.
Fawzia Zeraria Olivier Dry Jacqueline Fischer Yveline Frobert Jean-Yves Couraud Marie Conrath 《Journal of chemical neuroanatomy》1995,9(1):65-77
A monoclonal antibody directed against a peptide (PS5) specified by RNA complementary to the mRNA coding for substance P (SP), was used to label SP receptors in the rat spinal cord as demonstrated by light and electron microscopy. An immunocytochemical method (avidin-biotin-peroxidase) was used on vibratome sections from rats perfused with paraformaldehyde. Immunoreactivity was observed principally in the two superficial layers of the dorsal horn, in lamina X and the region of motoneurons. The labeling was absent when the antibody was preincubated with the complementary peptide (PS5) used as immunogen. Competition between the anti-complementary peptide antibody and different ligands was tested by preincubation of tissue sections with the ligand in the presence of peptidase inhibitors before addition of the antibody. A specific agonist (SP) or antagonist (spantide, RP 67580) at 10−6M led to total absence of labeling. These results indicate that under our experimental conditions, the anti-complementary peptide antibody recognizes a SP binding site in the rat spinal cord. Electron microscopic study of the two superficial laminae of the dorsal horn showed that immunolabeling was mainly localized extracellularly at apposing neuronal plasma membranes. It was mostly associated with axodendritic or axosomatic appositions. Occasionally labeling was observed between two axon terminals. In all cases, these appositions were non junctional. Generally, neuronal processes involved in these appositions did not contain large granular vesicles. These observations suggest that SP may act in a diffuse, nonsynaptic manner probably on targets distant from SP release sites. 相似文献
97.
Seventeen mycotoxins [aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG2),G2 (AFG2), aflatoxicol, sterigmatocystin, patulin, citrinin,penicillic acid, T-2 toxin, diacetoxyscirpenol, zeara-lenone,zearalenol ( and ß isomers 1:1), ochratoxin A, norso-lorinicacid, averufin, versicolorin A] were tested using the SOS Chromotest(PQ37 and PQ35). Six of the mycotoxins (AFB1, AFG1, AFB2, aflatoxicol,sterigmatocystin and versicolorin A) were genotoxic on PQ37strain with and without metabolic activation. The results obtainedwith metabolic activation are in agreement with positive resultsobtained in other tests of genotoxicity. Except for AFB2, thepresence of a double bond C8C9 in the dihydrobenzofurane(DHBF) ring explained the activity due to the formation of anepoxide, but the coumarin cyclopentenone ring also plays a rolein the qualitative differences of genotoxic activity. The wild-typeuvrB gene in PQ35 decreases the genotoxic response with andwithout metabolic activation. Without metabolic activation,only mycotoxins possessing the DHBF ring group and double linkageC8C9 exhibit a genotoxic effect.
3To whom correspondence should be addressed 相似文献
98.
99.
Louis Journeau Marc-Antoine Pistorius Ulrique Michon-Pasturel Marc Lambert Francois-Xavier Lapébie Alessandra Bura-Riviere Philippe de Faucal Patrick Jego Quentin Didier Cécile Durant Geoffrey Urbanski Baptiste Hervier Claire Toquet Christian Agard Olivier Espitia 《Autoimmunity reviews》2019,18(5):476-483
100.
Ernst K R?dland Morten Mattingsdal Ole K Olstad Reidun Ovsteb? Peter Kierulf Fredrik Muller Stig S Fr?land 《Medical mycology》2008,46(4):327-336
The objective of these studies was to investigate genes of importance in the pathogenesis of Aspergillus infections. To do so, we employed microarray methodology to explore gene expression in human monocytes infected with Aspergillus conidia as compared with unstimulated monocytes and those stimulated with lipopolysaccharide (LPS) signaling through TOLL-like receptor 4 (TLR4). We found 997 (P相似文献