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Prostatic epithelial cells and most primary prostate tumors are dependent on androgen for growth, but how androgen regulates cellular proliferation remains unsolved. Using poorly understood mechanisms, recurrent tumor cells evade the androgen requirement. We utilized androgen-dependent prostatic tumor cells to demonstrate that androgen exerts its effect on the cell cycle by influencing specific aspects of G1-S progression. Androgen depletion of these cells results in early G1 arrest, characterized by reduced cyclin-dependent kinase activity, and underphosphorylated retinoblastoma tumor suppressor protein (RB). The reduction in kinase activity was partially attributed to reduction of specific G1 cyclins and alternate regulation of cyclin-dependent kinase inhibitors. Using this information, we developed a reliable assay to assess the ability of specific G1 regulatory proteins to circumvent these controls and promote androgen-independent growth. As expected, inactivation of RB was required for progression through the cell cycle. Surprisingly, overexpression of G1 cyclins, which drives RB phosphorylation, was insufficient to promote androgen-independent cell cycle progression. Introduction of viral oncoproteins did promote G1-S progression in the absence of androgen, dependent on their ability to sequester RB and related proteins. These results provide the first evidence that multiple elements governing the G1-S transition dictate androgen-dependent growth, and the formation of androgen-independent prostatic tumors may be because of misregulation of these processes. 相似文献
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OBJECTIVES: To demonstrate the efficacy of a simple preparation for prostate biopsy (PBX) and to determine its potential cost savings. METHODS: One hundred fifty consecutive PBXs were performed using a Fleet enema and a single oral dose (300 mg) of ofloxacin as the pre-PBX preparation. RESULTS: Of the 150 PBXs we performed, only 1 (0.67%) patient developed a urinary tract infection. CONCLUSIONS: A simple and inexpensive pre-PBX preparation proved to be successful in preventing infectious complications and is presented as a potential model for inclusion in clinical pathways for diagnosing adenocarcinoma of the prostate. 相似文献
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RN Younes KC Yin CJ Amino M Itinoshe M Rocha e Silva D Birolini 《Canadian Metallurgical Quarterly》1998,22(1):2-5
The weeping fig, Ficus benjamina (Fb), is a relatively common indoor allergen. Many cases of perennial allergic rhinoconjunctivitis and allergic asthma caused by Fb hypersensitivity are not detected. These patients typically have proven sensitization to housedust mites and do not improve after avoidance of exposure (encasing) and specific immunotherapy. The number of Fb sensitizations is increasing in Germany, which can partly be explained by the cross-reactivity between Hevea brasiliensis (Hb) latex and Fb and the rapidly increasing number of mostly occupational latex allergies. But Fb itself is a potential sensitizer which is widely spread as ornamental plant in homes and offices. As relevant indoor allergen Fb ranks third after housedust mites and pets but before molds among our allergy patients. For diagnosis, prick-tests with Fb-latex seem to be more sensitive than in vitro-methods (RAST, CAPRAST). Fb plants should not be kept in the homes of atopic individuals or persons with latex (Hb) allergy. 相似文献
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KC Holmes 《Canadian Metallurgical Quarterly》1998,5(11):940-942
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