ISSN:1065-6995    

DOI:10.1006/cbir.1995.1014

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe distribution of fibronectin in tissues of four human foetuses (7‐14 gestation weeks/GW) and twenty seven pig foetuses (25‐114 days of gestation) was investigated using immunofluorescence and avidin/biotin methods. Fibronectin was abundant in the circulatory and gastrointestinal system and its derivates, in reticular stroma of immune organs, and in connective tissues and chorionic villi at all developmental sta

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1015

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe aliphatic polyamines, putrescine, spermine and spermidine belong to a category of molecules implicated in DNA replication. Their synthesis is strongly activated during the G1period and they have been implicated in the regulation of cell proliferation and differentiation. Terminal transferase is a DNA polymerase present in pre‐T and pre‐B cells and its expression can be modulated by phorbol ester treatment. In this study we have monitored the relationship of intracellular polyamine levels with terminal deoxynucleotidyl transferase down‐regulation induced by 12‐0‐tetradecanoyl phorbol myristate 13‐acetate treatment in the human pre‐B KM‐3 cell line. Phorbol myristate acetate can cause an increase, at 4 and 8 hours of differentiation, of intracellular levels of putrescine as well as a decrease in terminal deoxynucleotidyl transferase synthesis showing the probable involvement that polyamines have in the differen

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1016

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractRestriction Endonucleases (REs) may recognize, cleave and remove DNA from fixed chromatin producing specific chromosome banding patterns. However, the modifications produced in the chromatin fibre are not easy to evaluate and compare. The aim of the present investigation was to visualize differences resulting in the texture of the chromatin fibre from metaphase chromosomes after each digestion using digital image analysis (DIA) facilities. To this purpose, metaphase chromosomes derived from a L‐929 mouse cell line were digested with different REs (AluI, HpaII and HaeIII).Since light microscopy does not permit the observation of the chromatin fibre, DIA was performed on digitalized images of metaphase chromosomes under electron microscopy. The application of a LUT (Look Up Table) within the DIA software assigns a colour to each grey level of a digital image. The results obtained using a particular LUT, which permits the discrimination of specific chromatin fibre phenotypes resulting from each digestion, are reported and compared with those obtained under the light microscop

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1017

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractMacrophages derived from rat bone marrow were treated with macrophage colony stimulating factor (M‐CSF) to obtain a sufficient number of cells for the tumor necrosis factor (TNF‐α) assay. The present study has been designed to investigate whether the production of TNF‐α, which induces multinucleated giant cell formation, is regulated by polyanions such as lignin derivatives. ELISA for TNF‐α showed that the polyanion induced TNF‐α production by macrophages. The secretion of TNF‐α from the cells reached a maximum at 3‐6 h, and then showed a slight decline. Northern blotting of TNF‐α mRNA showed that the amount of TNF‐α reached a maximum within 1 h of macrophage culture in the presence of a lignin derivative. On the other hand, TNF‐α mRNA was undetectable in the control cells. It was concluded that stimuli such as that provided by lignin derivatives increases the amount of TNF‐α mRNA, which is then fo

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1018

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThe effect on phenotypic expression of rabbit vascular smooth muscle cells (SMC) of the interstitial matrix proteins collagen I and fibronectin, the basal lamina proteins collagen IV and laminin, and the serum adhesion protein vitronectin was examined in culture. Experiments were performed in foetal calf serum stripped of fibronectin and vitronectin to eliminate their confounding effects. All the proteins promoted adhesion to the plastic culture dish (in a concentration dependent manner) of SMC freshly isolated from the artery wall. These cells had a high volume density of myofilaments (Vvmyo) in their cytoplasm. Laminin was best at maintaining SMC with a high Vvmyo (Vvmyo = 49.8%) followed by collagen IV (41.7%). Cells plated on vitronectin showed the lowest Vvmyo (31.3%). The results support the concept that the SMC basal lamina has a role in maintaining cells in the high Vvmyo phenotype.

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1019

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractIsolated fragments produced by bisection of Amoeba proteus differ by their position in the original cell and by the presence or absence of the cell nucleus. Immediately after the operation, both types of anterior fragments preserve the former motory polarity, and do not interrupt locomotion. In the same time, all posterior fragments stop, round up and fail to react stimuli. In the second phase of experiment, these anterior fragments, which had no nucleus ceased to move, whereas the nucleated posterior ones resumed locomotion.It was demonstrated, that the behaviour of a fragment is primarily determined by the peripheral F‐actin distribution, which is different depending on the origin of the fragment either from the anterior or from the posterior cell region. Later, the "inherited" F‐actin distribution may be stabilized or reorganized in the presence of the nucleus, or desorganized in its abse

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1020

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractIn culture, cytochrome P‐450 levels fall rapidly with the result that hepatocytes are either used quickly or maintained in modified systems which prejudice their subsequent behaviour. In this study the effect of hypothermic preservation of hepatocytes on gelatin gels on levels of cytochrome P‐450 was investigated. In marked contrast to conventional cultures, hypothermic preservation (10°) maintained, over a 6‐day period, cytochrome P‐450 at levels similar to those of the more stable cytochrome b5. Cell storage on gelatin at 25° was associated with a conversion of cytochrome P‐450 to cytochrome P‐420. The procedure at 10° provides a valuable tool for toxicity testing, hepatocyte conservation an

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1021

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractEvidence of new cell formation from nucleoli (subdivisional cell replication) was observed in vitro and in vivo. Mouse melanoma cells, human fibroblasts, and rat mast cells were observed in tissue culture with phase contrast time‐lapse cinematography. Evidence of subdivisional cell replication seen in tissue culture was supported by observations of mast cells, cervical epithelial cells, melanoma cells, keratinocytes, and fungal spores in vivo. Indirect evidence for subdivisional cell replication was the presence of differentiated form and function in nuclei and nucleoli. Synergism between subdivisional replication and mitotic replication (subdivisional expansion) is believed to be a key to morphogenesis, whereby cellular and subdivisional zones act as biologic "molds". It is believed that subdivisional cell replication has a key role in maintenance of differentiated form in multicellular organisms, as well as in morphogenesi

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1022

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

ISSN:1065-6995    

DOI:10.1006/cbir.1995.1023

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY