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21.
BACKGROUND: Prostate cancer is the second leading cause of male death in the United States. The incidence increases most rapidly with age, and multiple genetic and epigenetic factors have been implicated in the initiation, progression, and metastasis of the cancer. Nevertheless, scientific knowledge of the molecular mechanisms underlying the disease is still limited; and hence treatment has only been partially successful. The objective of the current studies was to examine the role of caspase 3 (CPP32) and NAD(P)H:quinone oxidoreductase (NQO1) in the signaling of genistein-and beta-lapachone (bLap)-induced apoptosis in human prostate carcinoma cells PC3. RESULTS: Both genistein and bLap produced dose-dependent growth inhibition and treatment-induced apoptosis in PC3. Treatment with caspase 3 inhibitor, DEVD-fmk before exposure to genistein, significantly inhibited caspase 3 expression and treatment-induced apoptosis; implicating CPP32 as the main target in genistein-induced apoptosis in PC3. Contrary to this observation, inhibition of CPP32 did not significantly influence bLap-induced apoptosis; implying that the major target of bLap-induced apoptosis may not be the caspase. Treatment with NQO1 inhibitor, dicoumarol (50 microM), prior to exposure of PC3 to bLap led to significant decrease in bLap toxicity concurrent with significant decrease in treatment-induced apoptosis; thus implicating NQO1 as the major target in beta-lapachone-induced apoptosis in PC3. In addition, the data demonstrated that NQO1 is the major target in bLap-genistein (combination)-induced apoptosis. On the contrary, blocking NQO1 activity did not significantly affect genistein-induced apoptosis; implying that NQO1 pathway may not be the main target for genistein-induced apoptosis in PC3 cells. Furthermore, blocking NQO1 and CPP32 did not confer 100% protection against genistein-induced or bLap-induced apoptosis. CONCLUSION: The data thus demonstrate that both genistein-and bLap-induced apoptosis are mostly but not completely dependent on CPP32 and NQO1 respectively. Other minor alternate death pathways may be involved. This suggests that some death receptor signals do not utilize the caspase CPP32 and/or the NQO1 death pathways in PC3. The demonstrated synergism between genistein and bLap justifies consideration of these phytochemicals in chemotherapeutic strategic planning.  相似文献   
22.
Exposure of cultured preimplantation embryos to temperatures similar to those experienced by heat-stressed cows inhibits subsequent development. In this study, the effects of heat shock on the ultrastructure of two-cell bovine embryos were examined to determine mechanisms for inhibition of development. Two-cell embryos produced in vitro were harvested at approximately 28 h postinsemination and cultured for 6 h at one of three temperatures: 38.5 degrees C (cow body temperature), 41.0 degrees C (characteristic temperature for heat-stressed cows), or 43.0 degrees C (severe heat shock). Ultrastructural examinations revealed that both heat shocks resulted in the movement of organelles towards the center of the blastomere. In addition, heat shock increased the percentage of mitochondria exhibiting a swollen morphology. Distance between the membranes comprising the nuclear envelope was increased but only when embryos were treated at 43.0 degrees C. To determine whether ultrastructural responses to heat shock in culture were similar for embryos produced in vitro and in vivo, two-cell embryos were collected from superovulated Angus cows 48 h postinsemination and treated ex vivo for 6 h at 38.5 degrees C or 41.0 degrees C. Again, heat shock caused an increase in number of swollen mitochondria and movement of organelles away from the periphery of the blastomere. Exposure of two-cell bovine embryos to physiologically relevant elevated temperatures causes disruption in ultrastructural morphology that is inimical to development. The observation that overall morphology and response to heat was similar for embryos produced in vitro and in vivo implies that the former can be a good model for understanding embryonic responses to heat shock.  相似文献   
23.
The morbidity and mortality of infectious diseases are significantly increased in aged humans. Hence, vaccination has been suggested as a means to reduce or prevent the impact of infections on old individuals. However, it has remained unresolved whether or not standard vaccine adjuvants such as aluminum hydroxide (Alum) are similarly efficacious in old individuals, as compared to young adults. Here, we have investigated the effects of prototypic immunological adjuvants, complete Freund's adjuvant (CFA), incomplete Freund's adjuvant (IFA), or Alum on HEL-specific T cell responses in young adult and old mice. We report that independent of the adjuvant used, the induced T cell responses to the prototypic protein antigen hen eggwhite lysozyme (HEL) were similar in young adult and old mice in terms of cytokine production, T cell frequencies, determinant specificity, and T cell repertoire. The results suggest that vaccine adjuvants developed in young adults should be equally effective in inducing T cell immunity in old individuals.  相似文献   
24.
The electrophoretic pattern of serum proteins has been studied in short-term prehepatic portal hypertensive rats since atrophy is produced in the liver, which is the main origin of most of these proteins, during this postoperative period. After 28 days of evolution, rats (n = 9) with triple stenosing ligated portal vein showed hypoalbuminemia, hypo-alpha-globulinemia, hyper-alpha2-globulinemia and hyper-gamma-globulinemia, the albumin/globulin ratio decreased with respect to the control animals (n = 8). These alterations are associated with hepatic atrophy, portosystemic and portohepatic (44.4%) collateral circulation. The proteinogram alterations found in rats with short-term prehepatic portal hypertension suggest that hepatic failure exists in spite of potential portohepatic revascularization which is frequently originated by the development of portohepatic collateral circulation.  相似文献   
25.
26.
The cerebellum maintains balance and orientation, refines motor action, stores motor memories, and contributes to the timing aspects of cognition. We generated two mouse lines for making Cre recombinase-mediated gene disruptions largely confined to adult cerebellar granule cells. For this purpose we chose the GABA(A) receptor alpha6 subunit gene, whose expression marks this cell type. Here we describe mouse lines expressing Cre recombinase generated by 1) Cre knocked into the native alpha6 subunit gene by homologous recombination in embryonic stem cells; and 2) Cre recombined into an alpha6 subunit gene carried on a bacterial artificial chromosome (BAC) genomic clone. The fidelity of Cre expression was tested by crossing the mouse lines with the ROSA26 reporter mice. The particular alpha6BAC clone we identified will be valuable for delivering other gene products to cerebellar granule cells.  相似文献   
27.
Column biodesulphurization of coal is at the experimental stage and is influenced by many variables including temperature, pH, particle size, concentration of iron in solution, among others. Idle time in the washing process and the concentration of dissolved iron in the purged leachate are two variables with a definite effect on the yield of the desulphurization system. In the laboratory, several trials were run with columns packed with coal for different idle times: 1, 2, 3, 5, 6 and 7 days, and for different concentrations of iron in the purged leachate: 500 to 4,000 mg/l. The optimal values for the two variables; that is, those allowing for the highest desulphurization yields, were idle times of 3 and 5 days, which give an elimination of 56% and 49% of pyritic sulphur, respectively, and 3,000 mg/l of iron concentration in the purged leachate, giving a decrease in pyritic sulphur in coal of 57%.  相似文献   
28.
Earlier studies have indicated that Jun/AP-1 activity is associated with, and probably required for apoptosis induction by DNA-damaging and stress-inducing agents in human myeloid cells. To investigate this possibility, we examined the capacity of continuous treatments with etoposide (10 microM) and camptothecin (0.4 microM), and pulse treatments with X-rays (20 Gy), heat (2 h at 42.5 C) and cadmium chloride (2 h at 200 microM) followed by recovery, to provoke apoptosis and to simulate c-jun and c-fos expression and AP-1 binding in U-937 human promonocytic cells. All these treatments generated apoptosis with similar efficacy (50-60% apoptotic cells at 6 h of treatment or recovery). However, the capacity to increase c-jun and c-fos mRNA levels and to stimulate AP-1 binding was very different, ranging from more than a twelve-fold increase in the case of cadmium, to almost no increase in the case of heat-shock and etoposide. When the cells were pre-conditioned with a soft heat shock (1 h at 42 degrees C) the cadmium-provoked apoptosis was greatly inhibited, but the stimulation of AP-1 binding was not affected. The administration of cAMP-increasing agents also reduced the etoposide- and cadmium-provoked apoptosis. However, cAMP greatly stimulated c-jun and c-fos expression and AP-1 binding when applied together with etoposide (which itself was ineffective), and potentiated the cadmium-induced AP-1 binding. Conversely, retinoic acid abrogated the cadmium-provoked stimulation of AP-1 binding and transactivation capacity, and greatly inhibited the stimulation of binding caused by camptothecin and X-rays. However, retinoic acid did not inhibit the induction of apoptosis by these agents. These results indicate that Jun/AP-1 activity is not necessarily coupled with apoptosis, nor required for apoptosis induction by DNA-damaging and stress-inducing agents in human promonocytic cells.  相似文献   
29.
Bacterial beta-ketoacyl-acyl carrier protein (ACP) synthase III (KAS III, also called FabH) catalyzes the condensation and transacylation of acetyl-CoA with malonyl-ACP. In order to understand the mode of enzyme/substrate interaction and design small molecule inhibitors, we have expressed, purified, and crystallized a selenomethionyl-derivative of E. coli KAS III. Several lines of evidence confirmed that purified selenomethionyl KAS III was homogenous, stably folded, and enzymatically active. Dynamic light scattering, size exclusion chromatography, and mass spectrometry results indicated that selenomethionyl KAS III is a noncovalent homodimer. Diffraction quality crystals of selenomethionyl KAS III/acetyl-CoA complex, which grew overnight to a size of 0.2 mm(3), belonged to the tetragonal space group P4(1)2(1)2.  相似文献   
30.
Background: Colonization of the gastric mucosa by Helicobacter pylori is one of the most important causes of acute and chronic gastric pathologies in humans. Achieving the growth of H. pylori in liquid media is of great importance in the development of clinical studies. In this study, we developed a sequential optimization strategy based on statistical models to improve the conditions of liquid culture of H. pylori. Materials and Methods: Four statistical models were sequentially used. First, a Box‐Behnken design was used to select the best process conditions (shaking speed, inoculum concentration, and final volume of culture). Secondly, a general factorial design was used to evaluate the influence of adding gel blocks or gel beads (shape and composition). Then a D‐optimal reduce design was carried out to allow the selection of the most influential factors in increasing the cell concentration (culture media components). Finally, another Box‐Behnken design was used to optimize the concentration of the culture media components previously selected. Results: After 12 hours of liquid culture a concentration of 25 × 108 cells per mL (9.4 log10 cells per mL) of H. pylori was obtained, compared with a predicted 32 × 108 (9.5 log10 cells per mL), which means between 1 and 5 log10 units higher than some previous reports. Conclusions: The sequential statistical approach increased the planktonic H. pylori cell culture. The final culture media and conditions were: Brain Heart Infusion, blood agarose (1.5% w/v), lamb’s blood (3.18% v/v), DENT (0.11% v/v), and Vitox (0.52% v/v) at 60 rpm and 37 °C with filtered CO2 (5% v/v) bubbled directly into the culture media in a final volume of 76.22 mL.  相似文献   
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