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1.
Dietary polyamines promote the growth of azoxymethane-induced aberrant crypt foci in rat colon 总被引:1,自引:1,他引:1
We have examined whether dietary polyamines influence the formation and
initial growth of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in
rat colon. Effects of a combination of dietary polyamines at three dose
levels (putrescine: 50, 280, 740 nmol/g; spermidine: 10, 261, 763 nmol/g;
spermine: 1, 31, 91 nmol/g) in the polyamine-poor AIN-76A diet were studied
in animals in two different experimental situations: animals treated with
AOM alone and animals treated with AOM + difluoromethylornithine (DFMO), a
specific inhibitor of endogenous polyamine synthesis. In both experimental
situations, dietary polyamines enhanced the growth of ACF, expressed as the
number of large ACF (foci with three or more aberrant crypts, ACF > or =
3), whereas the formation of ACF, expressed as the number of ACF, was
apparently not altered. In animals treated with AOM alone, maximal growth
enhancing effect on ACF was nearly obtained with the median level of
dietary polyamine. In rats fed a low polyamine diet, basic AIN-76A, DFMO
reduced the growth of AOM-induced ACF by 83%. This inhibitory effect of
DFMO was counteracted by dietary polyamines in a dose- dependent manner,
and it was abolished at the highest level of polyamines. In conclusion, it
was demonstrated that dietary polyamines are able to enhance the growth of
AOM-induced ACF. Further, dietary polyamines reversed the DFMO-caused
inhibition of ACF growth, probably by compensating for the DFMO-reduced
endogenous polyamine synthesis.
相似文献
2.
Cotsiki M Lock RL Cheng Y Williams GL Zhao J Perera D Freire R Entwistle A Golemis EA Roberts TM Jat PS Gjoerup OV 《Proceedings of the National Academy of Sciences of the United States of America》2004,101(4):947-952
The mitotic spindle checkpoint protein Bub1 has been found to be mutated at low frequency in certain human cancers characterized by aneuploidy. Simian virus 40 large T antigen efficiently immortalizes rodent cells and occasionally transforms them to tumorigenicity. T antigen can also cause genomic instability, inducing chromosomal aberrations and aneuploidy. Here, we report an interaction between Bub1 and T antigen. T antigen coimmunoprecipitates with endogenous Bub1 and Bub3, another component of the spindle checkpoint complex. Genetic analysis demonstrates that the interaction of T antigen with Bub1 is not required for immortalization but is closely correlated with transformation. T antigen induces an override of the spindle checkpoint dependent on Bub1 binding. This interaction with proteins of the spindle checkpoint machinery suggests another role for T antigen and provides insight into its ability to cause chromosomal aberrations, aneuploidy, and transformation. 相似文献
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The EFIM Working Group on Political Issues in Internal Medicine in Europe Bauer W Schumm-Draeger PM Koebberling J Gjoerup T Garcia Alegria JJ Ferreira F Higgens C Kramer M Licata G Mittelman M O'hare J Unal S 《European Journal of Internal Medicine》2005,16(3):214-217
What will be the future of internal medicine in Europe? Because of rapidly growing concerns regarding the position of internal medicine in many European countries, the European Federation of Internal Medicine (EFIM) has established a working group to analyze the situation. Being well aware of the variation in working practices in the different countries, the members of the group used an “all-European” approach to answer the following questions:
- •Are there problems for internal medicine? If so, what are these problems and why?
- •Why do the health care systems in the European countries need internal medicine?
- •Why do patients need internal medicine?
- •What needs to be done?
5.
I. VANČOVÁ V. HAJNICKÁ M. SLOVÁK P. KOCÁKOVÁ G. C. PAESEN P. A. NUTTALL 《Parasite immunology》2010,32(6):460-463
Ticks exploit many evasion mechanisms to circumvent the immune control of their hosts including subversion of the communication language between cells of the immune system provided by chemokines and other cytokines. One subversive molecule secreted in the saliva of Rhipicephalus sanguineus is Evasin‐3, a structurally unique 7 kDa protein that selectively binds the neutrophil chemoattractants, CXCL8 and (with lower affinity) CXCL1. We compared anti‐human CXCL8 and anti‐mouse CXCL1/KC activities in salivary gland extracts prepared from adult Amblyomma variegatum, Rhipicephalus appendiculatus and Dermacentor reticulatus ticks during blood‐feeding. Both anti‐CXCL8 activity and anti‐CXCL1 activity were detected in all species and in both adult females and males, with consistently higher activity levels against CXCL8. These results suggest that Evasin‐3‐like activity is common amongst metastriate ixodid tick species, and provide further evidence of the importance to ticks in controlling neutrophils during blood‐feeding. As such, Evasin‐3 offers a new target for anti‐tick vaccine development. 相似文献
6.
Human mammary epithelial cell transformation through the activation of phosphatidylinositol 3-kinase 总被引:7,自引:0,他引:7
Recent studies have demonstrated that introduction of hTERT in combination with SV40 large T antigen (LT), small t antigen (st), and H-rasV12 suffices to transform many primary human cells. In human mammary epithelial cells (HMECs) expressing elevated c-Myc, activated H-Ras is dispensable for anchorage-independent growth. Using this system, we show that st activates the PI3K pathway and that constitutive PI3K signaling substitutes for st in transformation. Moreover, using constitutively active versions of Akt1 and Rac1, we show that these downstream pathways of PI3K synergize to achieve anchorage-independent growth. At lower levels of c-myc expression, activated PI3K also replaces st to complement H-rasV12 and LT and confers both soft agar growth and tumorigenicity. However, elevated c-myc expression cannot replace H-rasV12 for tumorigenesis. These observations begin to define the pathways perturbed during the transformation of HMECs. 相似文献
7.
Bauer W Schumm-Draeger PM Koebberling J Gjoerup T Garcia Alegria JJ Ferreira F Higgens C Kramer M Licata G Mittelman M O'Hare J Unal S;EFIM Working Group on Political Issues in Internal Medicine in Europe 《Acta clinica Belgica》2005,60(3):157-160
What will be the future of Internal Medicine in Europe? Because of rapidly growing concerns regarding the position of Internal Medicine in many European countries, the European Federation of Internal Medicine has established a working group to analyze the situation. Being well aware of the variation of working practices in the different countries, the members of the group used an "all-European" approach to answer the following questions: Are there problems for Internal Medicine, what problems and why? Why do the health care systems of the European countries need Internal Medicine? Why do the patients need Internal Medicine? What needs to be done? Internal Medicine is the modern, clinical and scientific medical discipline taking care of adult patients with one or more complex, acute or chronic illnesses. Internal Medicine is the cornerstone of integrated health care delivery service that is needed today. Decision-makers in politics and hospitals, insurers, journalists and the general public need a better understanding of what Internal Medicine can offer to the health care system and to the individual patient. 相似文献
8.
Andrea Necchi MD Vito Cucchiara MD Petros Grivas MD PhD Gennady Bratslavsky MD Joseph Jacob MD Philippe E. Spiess MD MS Ethan S. Sokol PhD Jonathan Keith Killian MD PhD Douglas Lin MD PhD Shakti Ramkissoon MD PhD Richard S. P. Huang MD Russell W. Madison PhD Jeffrey M. Venstrom MD Alexa B. Schrock PhD Natalie Danziger BS Brennan Decker MD PhD Ole Gjoerup PhD Ryon P. Graf PhD Geoffrey R. Oxnard MD Hanna Tukachinsky PhD Jeffrey S. Ross MD 《Cancer》2021,127(24):4557-4564
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