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91.
Dallinga JW Moonen EJ Dumoulin JC Evers JL Geraedts JP Kleinjans JC 《Human reproduction (Oxford, England)》2002,17(8):1973-1979
BACKGROUND: Various studies have been performed in which potential effects of xenoestrogens on fertility or sperm parameters were investigated by comparing groups of subjects exposed to different levels of these chemicals. METHODS: In our study we used an alternative approach, as we selected one group of men with very poor semen quality and another group with normal semen quality and determined the blood organochlorine contents in order to determine whether a difference in these levels could be established. Organochlorine compounds, including polychlorinated biphenyls (PCB) and PCB metabolites, were detected using gas chromatography. The concentrations were compared between both groups, and related to semen parameters. RESULTS: A comparison of both groups did not reveal significant differences in organochlorine levels. Linear relationships were found when PCB and metabolite concentrations were related to the age of the volunteers. Focusing on the subgroup of men with normal semen quality showed that sperm count and sperm progressive motility were inversely related to the concentrations of PCB metabolites within this group. CONCLUSIONS: The finding of a significantly decreased sperm count in relation to an elevated PCB metabolite level within the subgroup of men with normal semen quality is important. This is the first time that a correlation between exposure to environmental pollutants with endocrine-disrupting capacity and human sperm quality has been observed. 相似文献
92.
Tumor-associated macrophages express lymphatic endothelial growth factors and are related to peritumoral lymphangiogenesis 总被引:53,自引:0,他引:53 下载免费PDF全文
Schoppmann SF Birner P Stöckl J Kalt R Ullrich R Caucig C Kriehuber E Nagy K Alitalo K Kerjaschki D 《The American journal of pathology》2002,161(3):947-956
Formation of lymphatic metastasis is the initial step of generalized spreading of tumor cells and predicts poor clinical prognosis. Lymphatic vessels generally arise within the peritumoral stroma, although the lymphangiopoietic vascular endothelial growth factors (VEGF)-C and -D are produced by tumor cells. In a carefully selected collection of human cervical cancers (stage pT1b1) we demonstrate by quantitative immunohistochemistry and in situ hybridization that density of lymphatic microvessels is significantly increased in peritumoral stroma, and that a subset of stromal cells express large amounts of VEGF-C and VEGF-D. The density of cells producing these vascular growth factors correlates with peritumoral inflammatory stroma reaction, lymphatic microvessel density, and indirectly with peritumoral carcinomatous lymphangiosis and frequency of lymph node metastasis. The VEGF-C- and VEGF-D-producing stroma cells were identified in situ as a subset of activated tumor-associated macrophages (TAMs) by expression of a panel of macrophage-specific markers, including CD68, CD23, and CD14. These TAMs also expressed the VEGF-C- and VEGF-D-specific tyrosine kinase receptor VEGFR-3. As TAMs are derived from monocytes in the circulation, a search in peripheral blood for candidate precursors of VEGFR-3-expressing TAMs revealed a subfraction of CD14-positive, VEGFR-3-expressing monocytes, that, however, failed to express VEGF-C and VEGF-D. Only after in vitro incubation with tumor necrosis factor-alpha, lipopolysaccharide, or VEGF-D did these monocytes start to synthesize VEGF-C de novo. In conclusion VEGF-C-expressing TAMs play a novel role in peritumoral lymphangiogenesis and subsequent dissemination in human cancer. 相似文献
93.
Johannes Hartmann Volker Maaßen Peter Rieber Harald Fricke 《European journal of immunology》1995,25(9):2626-2631
94.
95.
Christian Stock Birgit Gassner Christof R. Hauck Hannelore Arnold Sabine Mally Johannes A. Eble Peter Dieterich Albrecht Schwab 《The Journal of physiology》2005,567(1):225-238
Their glycolytic metabolism imposes an increased acid load upon tumour cells. The surplus protons are extruded by the Na+ /H+ exchanger (NHE) which causes an extracellular acidification. It is not yet known by what mechanism extracellular pH (pHe ) and NHE activity affect tumour cell migration and thus metastasis. We studied the impact of pHe and NHE activity on the motility of human melanoma (MV3) cells. Cells were seeded on/in collagen I matrices. Migration was monitored employing time lapse video microscopy and then quantified as the movement of the cell centre. Intracellular pH (pHi ) was measured fluorometrically. Cell–matrix interactions were tested in cell adhesion assays and by the displacement of microbeads inside a collagen matrix. Migration depended on the integrin α2β1. Cells reached their maximum motility at pHe ∼7.0. They hardly migrated at pHe 6.6 or 7.5, when NHE was inhibited, or when NHE activity was stimulated by loading cells with propionic acid. These procedures also caused characteristic changes in cell morphology and pHi . The changes in pHi , however, did not account for the changes in morphology and migratory behaviour. Migration and morphology more likely correlate with the strength of cell–matrix interactions. Adhesion was the strongest at pHe 6.6. It weakened at basic pHe , upon NHE inhibition, or upon blockage of the integrin α2β1. We propose that pHe and NHE activity affect migration of human melanoma cells by modulating cell–matrix interactions. Migration is hindered when the interaction is too strong (acidic pHe ) or too weak (alkaline pHe or NHE inhibition). 相似文献
96.
97.
C4a anaphylatoxin levels as an indicator of disease activity in systemic lupus erythematosus 总被引:1,自引:1,他引:1 下载免费PDF全文
G Wild J Watkins A M Ward P Hughes A Hume N R Rowell 《Clinical and experimental immunology》1990,80(2):167-170
The use of a synthetic protease inhibitor, nafamstat mesilate, has enabled reliable estimations of in vivo complement activation to be made in systemic lupus erythematosus (SLE). Elevation of C3a anaphylatoxins was found in two out of 24 patients and elevation of C4a anaphylatoxins was found in 20 out of 24 patients, confirming that complement activation, predominantly by the classical pathway, is a common occurrence in the disease. Significantly higher levels of C4a anaphylatoxin were found in 16 patients, with more aggressive disease requiring supplementary treatment with azathioprine, while the remaining eight patients, with less severe disease, required purely steroid therapy. Very strong associations between elevated C4a anaphylatoxins and raised DNA antibody titres, C1q binding activity and low complement C4 levels were also observed, suggesting that anaphylatoxin measurement may be a sensitive additional method for monitoring disease activity in SLE. 相似文献
98.
Taams LS Vukmanovic-Stejic M Smith J Dunne PJ Fletcher JM Plunkett FJ Ebeling SB Lombardi G Rustin MH Bijlsma JW Lafeber FP Salmon M Akbar AN 《European journal of immunology》2002,32(6):1621-1630
Anergic/suppressive CD4+CD25+ T cells have been proposed to play an important role in the maintenance of peripheral tolerance. Here we demonstrate that in humans these cells suppress proliferation to self antigens, but also to dietary and foreign antigens. The suppressive CD4+CD25+ T cells display a broad usage of the T cell receptor Vbeta repertoire,suggesting that they recognize a wide variety of antigens. They reside in the primed/memory CD4+CD45RO+CD45RB(low) subset and have short telomeres, indicating that these cells have the phenotype of highly differentiated CD4+ T cells that have experienced repeated episodes of antigen-specific stimulation in vivo. This suggests that anergic/suppressive CD4+CD25+ T cells may be generated in the periphery as a consequence of repeated antigenic encounter. This is supported by the observation that highly differentiated CD4+T cells can be induced to become anergic/suppressive when stimulated by antigen presented by non-professional antigen-presenting cells. We suggest that besides being generated in the thymus, CD4+CD25+ regulatory T cells may also be generated in the periphery. This would provide a mechanism for the generation of regulatory cells that induce tolerance to a wide array of antigens that may not be encountered in the thymus. 相似文献
99.
Marla Gearing Johannes Tigges Hiroshi Mori Suzanne S. Mirra 《Neurobiology of aging》1996,17(6):54-908
Because aged nonhuman primates show β-amyloid (Aβ) deposition in senile plaques and blood vessels similar to that seen in human aging and AD, we used C-terminal specific antibodies to Aβ40 and Aβ42 to investigate Aβ peptide length in the brains of 11 aged rhesus monkeys and a 59-year-old chimpanzee. In contrast to AD, where the earliest and most prominent form of Aβ in senile plaques is Aβ42, in the monkey, Aβ40-positive plaques predominated. The ratio of Aβ4): Aβ42-positive plaques averaged 2.08 in the monkey, as compared to a mean ratio of 0.37 in 68 human AD subjects (p < 0.001). Aβ40 was also more prominent in the chimpanzee than in humans. Possible explanations for these findings include species differences in the cleavage of Aβ from the amyloid precursor protein or in the activity of a putative carboxy peptidase forming Aβ40 from Aβ42 in situ. 相似文献
100.
Embryonic fibroblasts of BALB/Mo mice carrying the endogenous genome of Moloney murine leukemia virus (M-MuLV) in addition to murine type C viruses were fused with Swiss mouse thymocytes, B lymphocytes, macrophages, or embryonic fibroblasts. We wanted to determine whether these cells contained physiological factors involved in induction of the integrated viral genome(s). Fusion with thymocytes and, to a lesser extent, fusion with B lymphocytes induced viral genome expression as demonstrated by the appearance of viral structural protein p30 detected by immunofluorescence. Maximal expression of p30 was observed about 36 hr after the fusion event, using thymocytes from 1- to 2-week-old Swiss mice. This temporary expression of p30 was not accompanied by release of infectious virus. Fusion of BALB/Mo fibroblasts with Swiss mouse macrophages or embryonic fibroblasts led to neither the production of p30 nor the release of detectable infectious virus. These results suggest the existence of thymocyte-specific and possibly B lymphocyte-specific factor(s) involved in the control of expression of integrated viral genome(s). 相似文献