Tamoxifen attenuates glucocorticoid actions on bone formation in vitro

Tamoxifen is a synthetic estrogen analog which may regulate osteogenesis in vivo by virtue of its antiglucocorticoid properties. We have examined tamoxifen regulation of glucocorticoid-induced osteogenesis in two different in vitro bone systems: the chicken periosteal osteogenesis model (CPO) and rat bone marrow stromal cells (RBMC). Hormone uptake studies were conducted with the osteosarcoma cell line, ROS 17/2.8. In the CPO model, alkaline phosphatase (AP) activity and collagen synthesis were stimulated by the glucocorticoid dexamethasone (Dex; 0.1 microM). These Dex-mediated effects were inhibited by increasing concentrations of tamoxifen (10-100 microM). Similarly, in the RBMC model, Dex-dependent (0.01 microM Dex) mineralized tissue formation and AP activity were blocked by tamoxifen (0.1 microM). Although tamoxifen inhibited Dex-mediated increases of AP activity in ROS 17/2.8 cells, it did not inhibit uptake of 3H-Dex or of 3H-estrogen. Northern analyses showed that tamoxifen did not affect messenger RNAs (mRNAs) for AP. Tamoxifen did seem to reduce mRNA for collagen type I, but not bone sialoprotein, osteopontin, and osteocalcin. Dex-induced increases for all proteins mRNAs in the RBMC model were not reduced by tamoxifen. Similarly, tamoxifen had no effects on cellular proliferation. We conclude that tamoxifen has no direct effect on gene expression of bone-related proteins of osteoblastic cells. Further, in the ROS 17/2.8 cell line, the antiglucocorticoid properties of tamoxifen do not appear to be mediated through either Dex or estrogen receptors.     

Impact of differentially significant others on role involvement: An experiment with prison social types.

Examined whether prison social-type behavior is congruent with self or is a function of the significance of different audiences, and assessed the degree of involvement in different roles in the presence of different audiences. 40 adult male prisoners were assigned to 3 experimental and 1 audience group. Results show that (a) when fellow inmates served as audience, the typical prisoner "con" role was rated higher in involvement; (b) when social welfare students comprised the audience, the social worker's role was rated higher in involvement; and (c) involvement in the custodial officer role before a custodian audience was not rated higher. When Ss were classified according to social type, the rated involvement in prisoner roles was congruent with the expectations for each social type. Prison social-type behavior is interpreted as a situational response to specific primary deprivations influenced by the degree of significance of specific audiences. (51 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of suramin-related and other clinically therapeutic polyanions on protein kinase C activity

The mechanism of the antineoplastic effects of suramin may involve interference with signal transduction, but in general is not well understood. We examined several polyanions to determine their effects on the kinase activity of the protein kinase C (PKC) beta1 and other PKC isoforms. Similar to suramin, a phosphorothioate oligodeoxynucleotide 28-mer homopolymer of cytidine (SdC28) inhibited the phosphatidylserine and Ca2+-dependent phosphorylation of an epidermal growth factor receptor octapeptide substrate. The inhibition by suramin was mixed competitive/noncompetitive with respect to ATP, but uncompetitive with respect to substrate. In contrast, the inhibition by SdC28 was competitive with respect to substrate (Ki = 5.4 microM) and not competitive with respect to ATP. The PKC alpha and beta1 isoforms were inhibited to the same extent with SdC28, while PKC epsilon was not inhibited. SdC28, in the absence of lipid cofactor, stimulated substrate phosphorylation, and in the absence of substrate induced PKC beta1 autophosphorylation. Similar behavior was seen with another polyanion, the polysulfated carbohydrate pentosan polysulfate (polyxylyl hydrogen sulfate). H4, a bis-naphthalene disulfonate tetraanion structurally related to suramin, also inhibited kinase activity but was not competitive with respect to ATP. Dianions closely related to H4 failed to inhibit PKC beta1, suggesting that multiple (>2) negative charges are required. The interactions of polyanions with PKC are complex, and are dependent on the molecular structure of the polyanion, the presence of cofactors, and the PKC isoform.     

Young people considering nursing as a career: starters vs. non-starters

This study focused on applicants who were accepted to a nursing education program but did not begin their studies, thus wasting time, effort and money. Of 953 accepted applicants, 27% did not enter the program. Significant variables differentiating starters from non-starters were higher psychometric score, higher paternal education, lower priority for nursing studies, older age, non-Israeli country of birth and not completed army service. The study relating to starters vs. non-starters is one aspect of a large study (Ehrenfeld, Rotenberg, Sharon, & Bergman, 1995). In most nursing education programs the number of applicants exceed the faculty's capacity, and suitable candidates must be rejected. It is therefore both wasteful and disappointing when accepted applicants change their mind and do not actually begin in the program. In light of the costs and complexities involved in the student screening process and the continuous efforts extended today all over the world to raise the standards of nursing education and care, the factors differentiating starters from non-starters may have important implications. The aim of the present study was to evaluate the screening process at the Tel Aviv University baccalaureate nursing program and determine which variables were predictive of starters and non-starters among accepted applicants.     

Ferroelectric Ceramics in the PbMg1/3Nb2/3O3-PbCd1/3Nb2/3O3 System

Solid solutions (1-x)PbMg_1/3Nb_2/3O₃ + xPbCd_1/3Nb_2/3O₃ with x = 0-0.30 are investigated with purpose to work out a capacitor ceramics with good dielectric properties and low sintering temperature. It is found that the perovskite phase forms at sintering near to 980°C and begins to decompose at higher temperatures. When x grows from 0 to 0.30, the Curie temperature linearly grows from -10°C to +25°C, the dielectric permittivity ε_m in the Curie point T_C decreases from 18000 to 6800 and the phase transition becomes more diffused. The dielectric permittivity at room temperature is rather high and the temperature stability is improved. The system is of interest, because it can serve as a base for working out some ceramic materials for capacitors with low sintering temperature, which needs of no special atmosphere at burning.     

Commercial trials of an oscillation mechanism for continuous-caster molds with spring connectors

One of the main goals in the improvement of continuous casting technology is to improve the quality of the cast semifinished products. The most common surface defects on these products (folds, bleeders, coarse traces of mold oscillation, hanger tears) are related to the stability of operation of the mold oscillation mechanism and its drive and the accuracy with which the prescribed level of metal is maintained in the mold. Research done by the consortium MMZ-NKMZ-VNIIMETMASh on the development of a spring-based mold oscillation mechanism has made it possible to gain valuable experience in this area, design new components and oscillation mechanisms, and arrive at a better understanding of the technological aspects of their operation and the service requirements of such mechanisms on high-speed continuous casters. The Moldavian plant plans to continue its tests of an experimental oscillation mechanism with spring connectors in order to further improve the surface quality of continuous-cast semifinished products and stabilize the casting operation.     

Imaging of a case of wirsungorrhagia

We report a case of wirsungorrhagia related to rupture of a pseudoaneurysm into the duct of Wirsung in a patient with chronic pancreatitis. Upper gastrointestinal endoscopy showed blood coming from the papilla of Vater suggesting wirsungorrhagia. Non-contrast computed tomography showed a spontaneous hyperdensity and arteriography showed an extravasation of contrast within a very large duct of Wirsung confirming wirsungorrhagia. Arteriography and dynamic computed tomography revealed a pseudoaneurysm from the left gastric artery. The pseudoaneurysm was successfully embolized with four steel microcoils, after super-selective catheterization of small branch of the left gastric artery, keeping gastric and liver vascularization.