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Starfish oocytes, eggs, and embryos are popular models for studying meiotic maturation, fertilization, and embryonic development. Their large (170- to 200-microm) oocytes are obtainable in copious amounts and are amenable to manipulations that mammalian oocytes are not. The most formidable obstacle to working with marine oocytes is their seasonal availability, yet a successful means of preserving them for use during the nonreproductive season has not been reported. The aim of this study was to investigate the response of starfish oocytes to freezing with rapid and slow cooling rates under a variety of conditions to develop a cryopreservation protocol for these cells. Cryomicroscopic observation revealed that starfish oocytes in isotonic medium undergo intracellular ice formation (IIF) at very high subzero temperatures, such that the mean difference between the temperature of extracellular ice formation (T(EIF)) and IIF (TI(IF)) was less than 3 degrees C and the average T(IIF) was approximately between -4 and -6 degrees C. Neither partial cellular dehydration nor addition of the cryopreservative dimethyl sulfoxide significantly depressed the T(IIF). Under some conditions, we observed ice nucleation at multiple locations within the cytoplasm, suggesting that several factors contribute to the unusually high T(IIF) during controlled-rate freezing and thus vitrification may be a more suitable method for cryopreserving these cells. 相似文献
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Akdemir ZS Tatli II Saracoğlu I Ismailoğlu UB Sahin-Erdemli I Caliş I 《Phytochemistry》2001,56(2):189-193
Two new polyphenolic compounds, myricetin 3-O-(2"-O-galloyl)-beta-D-glucopyranoside and (-)-6-chloroepicatechin, were isolated from the aerial parts of Geranium pratense subsp. finitimum (Woronow) Knuth, along with three known polyphenolic compounds [quercetin 3-O-(2"-O-galloyl)-beta-D-glucopyranoside, quercetin 3-O-(2"-O-galloyl)-beta-D-galactopyranoside, methyl gallate] and tryptophan. Quercetin 3-O-beta-D-glucopyranoside, quercetin 3-O-beta-D-galactopyranoside, quercetin 3-O-(2"-O-galloyl)-beta-D-glucopyranoside and quercetin 3-O-(2"-O-galloyl)-beta-D-galactopyranoside were found to be effective against free radical induced impairment of endothelium-dependent relaxation in isolated rat aorta. 相似文献
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Palanduz S Sever MS Oztürk S Taşçioğlu C Karan MA Sönmez G Cefle K Güler K 《Cell biology and toxicology》1999,15(1):13-17
We analyzed the induction of sister chromatid exchange (SCE) by cyclosporin A (CsA) as a marker of genotoxic potential. In 30 patients undergoing renal transplantation, SCE induction was tested before the introduction of CsA and 3 months later. We found that SCE frequency increased significantly at the end of 3 months. To our knowledge, this is the first study demonstrating in vivo induction of SCE by CsA in humans. We conclude that CsA has a genotoxic potential on human lymphocytes. 相似文献
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Ozer E Sağol O Kuyucuoğlu F 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1999,21(1):42-46
OBJECTIVE: To investigate the proliferative activity and mean nuclear volume (MNV) of melanocytic skin tumors. STUDY DESIGN: Proliferative activity, assessed by immunostaining for the Ki-67 monoclonal antibody (reactive with all actively cycling cells), and MNV, estimated by means of a stereologic method, were determined in 60 cutaneous melanocytic tumors, including 28 primary malignant melanomas (PMM), 13 compound nevi (CN), 11 dysplastic nevi and 8 metastatic malignant melanomas. RESULTS: Both MNV and Ki-67 expression differed significantly between CN and other melanocytic tumors and showed a good correlation with Clark's level (a well-established prognostic parameter in PMM). CONCLUSION: The association of proliferative activity and quantitative nuclear features may be helpful in the interpretation of the degree of malignancy in melanocytic skin tumors. 相似文献
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Gürünlüoğlu R Bayramiçli M Doğan T Numanoğlu A 《Plastic and reconstructive surgery》1999,103(5):1539-1540
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