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排序方式: 共有775条查询结果,搜索用时 46 毫秒
1.
Tetyana Denysenko Luisa Gennero Carola Juenemann Isabella Morra Paolo Masperi Vincenzo Ceroni Antonella Pragliola Antonio Ponzetto Antonio Melcarne 《Cell biochemistry and function》2014,32(2):164-176
Glioblastomas (GBMs) are the most lethal primary brain tumours. Increasing evidence shows that brain tumours contain the population of stem cells, so‐called cancer stem cells (CSCs). Stem cell marker CD133 was reported to identify CSC population in GBM. Further studies have indicated that CD133 negative cells exhibiting similar properties and are able to initiate the tumour, self‐renew and undergo multilineage differentiation. GBM is a highly heterogeneous tumour and may contain different stem cell populations with different functional properties. We characterized five GBM cell lines, established from surgical samples, according to the marker expression, proliferation and differentiation potential. CD133 positive cell lines showed increased proliferation rate in neurosphere condition and marked differentiation potential towards neuronal lineages. Whereas two cell lines low‐expressing CD133 marker showed mesenchymal properties in vitro, that is high proliferation rate in serum condition and differentiation in mesenchymal cell types. Further, we compared therapy resistance capacity of GBM cell lines treated with hydroxyurea. Our results suggest that CSC concept is more complex than it was believed before, and CD133 could not define entire stem cell population within GBM. At least two different subtypes of GBM CSCs exist, which may have different biological characteristics and imply different therapeutic strategies. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
2.
Dexamethasone regulates bile acid synthesis in monolayer cultures of rat hepatocytes by induction of cholesterol 7 alpha-hydroxylase. 总被引:2,自引:1,他引:1 下载免费PDF全文
To study the effect of steroid hormones on bile acid synthesis by cultured rat hepatocytes, cells were incubated with various amounts of these compounds during 72 h and conversion of [4-14C]cholesterol into bile acids was measured. Bile acid synthesis was stimulated in a dose-dependent way by glucocorticoids, but not by sex steroid hormones, pregnenolone or the mineralocorticoid aldosterone in concentrations up to 10 microM. Dexamethasone proved to be the most efficacious inducer, giving 3-fold and 7-fold increases in bile acid synthesis during the second and third 24 h incubation periods respectively, at a concentration of 50 nM. Mass production of bile acids as measured by g.l.c. during the second day of culture (28-52 h) was 2.2-fold enhanced by 1 microM-dexamethasone. No change in the ratio of bile acids produced was observed during this period in the presence of dexamethasone. Conversion of [4-14C]7 alpha-hydroxycholesterol, an intermediate of the bile acid pathway, to bile acids was not affected by dexamethasone. Measurement of cholesterol 7 alpha-hydroxylase activity in homogenates of hepatocytes, incubated with 1 microM-dexamethasone, showed 10-fold and 90-fold increases after 48 and 72 h respectively, as compared with control cells. As with bile acid synthesis from [14C]cholesterol, no change in enzyme activity was found in hepatocytes cultured in the presence of 10 microM steroid hormones other than glucocorticoids. Addition of inhibitors of protein and mRNA synthesis lowered bile acid production and cholesterol 7 alpha-hydroxylase activity and prevented the rise of both parameters with dexamethasone, suggesting regulation at the mRNA level. We conclude that glucocorticoids regulate bile acid synthesis in rat hepatocytes by induction of enzyme activity of cholesterol 7 alpha-hydroxylase. 相似文献
3.
Ilari Suominen Jarmo Käpylä Carola Tilgmann Virpi Glumoff Pekka Mäntsälä 《FEMS microbiology letters》1988,55(1):3-8
Abstract In a previous study, we have described unusual cross-reactions among monoclonal antibodies (Mabs) to bacteria and in particular to the Inaba and Ogawa serotypes of Vibrio cholerae . In this study, the extent to which the binding sites of both antibodies and antigens overlap has been investigated by competitive binding and idiotypic analysis. The competitive binding data indicate that the cross-reactive binding of the Inaba Mabs to the Ogawa vibrios can be abolished by incubation with higher affinity Ogawa Mabs. However, rabbit antiserum raised against the Inaba series does not react with the Ogawa series, indicating that anti-Inaba Mabs do not share idiotypic determinants with anti-Ogawa Mabs. The results therefore suggest that the two sets of antibodies recognise different determinants which are closely related in spatial terms, and which consequently do not permit simultaneous binding of the two types of monoclonal antibody. 相似文献
4.
5.
Karsten Pedersen Carola Holmström Anna-Kerstin Olsson Amelie Pedersen 《Archives of microbiology》1986,145(1):1-8
A budding coccoid bacterium, (CH1), a Vibrio sp. and a Pseudomonas sp. were investigated for factors governing their attachment to glass surfaces in static batch culture and laminar flow continuous culture systems. An analysis of variance showed that the three species exhibited very different responses. For CH1 attachment was dependent on cell density, incubation time and nutrient concentration. The Vibrio sp. was affected by nutrient concentration while the attachment of the Pseudomonas sp. was independent of cell density, incubation time and nutrient concentration. A comparison of attachment to hydrophilic and hydrophobic surfaces showed that attachment of the Vibrio sp. and CH1 to hydrophilic surfaces was 3 and 10 times greater respectively than to hydrophobic surfaces while Pseudomonas attached in equal numbers to both surfaces. The continuous culture system with defined flow hydrodynamics and growth conditions at steady state revealed a random sampling effect 3 times smaller than the batch culture system did. When the biofilm development of Pseudomonas sp. was followed during 46 h at different fluid shear under laminar and turbulent flow conditions, the former biofilm reached 3.3·108 cells·cm-2 and the latter 8.2·107 cells·cm-2.Non-common abbreviation NSS
Nine salt solution 相似文献
6.
Summary By means of SDS-polyacrylamide-gel electrophoresis, molecular weights of 15000, 28000, 59000, 116000 and 220000 were determined for the main sieve tube proteins from Cucurbita maxima. 相似文献
7.
Abstract The gonochoristic syllid Petitia amphophthalma is one of the truly interstitial polychaetes. P. amphophthalma does not show any epitokous modifications at maturity such as those that usually occur in syllids. The reproductive structures are unique: the male genital organs consist of a seminal vesicle in chaetigers 6–10, subdivided into a dorsal part tightly filled with spermatozoa and a ventral part with contents in different stages of spermatogenesis, one pair of sperm ducts and conspicuous gland cells situated in chaetigers 10 and 11. Their glandular secretions are discharged into the sperm duct together with those of other types of gland cells that form the duct. The oocytes develop freely within the body cavity of the females. Each of the fertile segments possesses a paired oviduct ending in a large ciliated funnel. Sperm ducts and oviducts are probably modifications of excretory organs; nephridia are absent in segments where gonoducts occur. A direct sperm transfer by lytic opening of the integument of the female and internal fertilization are inferred. Copyright © 1996 Published by Elsevier Science Ltd on behalf of the Royal Swedish Academy of Sciences 相似文献
8.
Carola Borries Volker Sommer Arun Srivastava 《International journal of primatology》1994,15(3):421-443
We studied grooming among adults of a one-male multifemale troop of free-ranging Hanuman langurs (Presbytis entellus)living near Jodhpur, India, for 9 years. The 11–13 females devoted about 6% of their day to allogrooming. Adult males, whose
tenures averaged 2.2 years, were transient figures in the troop's history, as reflected by their rather peripheral role in
the grooming network. Females groomed males 4–40 times more frequently (1006 episodes) than vice versa- (176 episodes). Adult
females received 97% of all grooming from other adult females (6655 episodes). Although females exhibited an age- inversed
dominance hierarchy, they did not compete for grooming access to particular troop mates. Dyads of all possible rank differences
occurred as frequently as expected: 51% of grooming was directed up the hierarchy and 49% down it. Young, high- ranking individuals
gave and received significantly more grooming than the oldest, low- ranking females did. The pattern seemed to be influenced
by kin selection because of the presumably high degree of female relatedness. They invested most in troopmates with the highest
reproductive value, i.e., the youngest individuals. This trend was coupled with a preference of closest kin (mothers and daughters).
Reciprocity was the outstanding feature since all adult females groomed and were groomed by all others. Such a tight social
net might establish the necessary cohesion during frequent territorial disputes with neighboring troops. 相似文献
9.
Per Mrin Roland Rosmond Bengt-ke Bengtsson Carola Gustafsson Gran Holm Per Bjmtorp 《Obesity (Silver Spring, Md.)》1994,2(3):263-270
Visceral obese men were characterized by a decreased total GH secretion and diminished peak amplitude, size, and number. T-substitution was followed by elevation of IGF-I levels. The IGF-I increase correlated with the elevation of T-concentration, and was most pronounced in men with the lowest concentrations of free T from the outset. There were no detectable changes in total quantity, amplitude, size or number of peaks of GH secretion. Glucose, cholesterol and triglycerides as well as diastolic blood pressure decreased. There were no changes in thyroid or hematology variables. Visceral obesity in men has been reported to be characterized by low testosterone (T) and insulin-like growth factor I (IGF-I) concentrations, the latter suggesting a relative growth hormone (GH) deficiency. Since T and GH-secretions are interrelated, men with visceral obesity were substituted with T for 14 days, and diurnal secretion pattern of GH as well as IGF-I concentrations, and metabolic variables were followed. T-substitution of visceral obese men is followed by an elevation of IGF-I concentrations. It is suggested that this might be due either to minor, non-detectable increases in GH secretion, or to direct effects of T on IGF-I concentrations. The regulatory mechanisms by which T-administration are leading to metabolic and anthropometric improvements, might be direct effects of T, with or without mediation via GH secretion. 相似文献
10.
Margot Schulz T. Klockenbring Carola Hunte Heide Schnabl 《Plant biology (Stuttgart, Germany)》1993,106(2):143-145
Western immunoblot analysis of protein extracts prepared from epidermal peels, whole leaves, and mesophyll protoplasts with ubiquitin and PEPCase antibodies indicated ubiquitinated PEPCase bands and degradation products only in crude extracts which have been obtained in the presence of the proteolysis inhibitors leupeptin and hemin. After ammonium sulfate precipitation and further purification, PEPCase forms were stable and not ubiquitinated. It is assumed, that only a certain part of PEPCase is degraded via the ubiquitin-dependent proteolysis. 相似文献