Greater behavioral effects of stress in immature as compared to mature male mice

The effect of sexual maturity on behavioral effects of stress was examined in male mice. Immature (4-week-old) or mature (8-week-old) animals were subjected to either social stress (exposure to an isolated adult male) or restraint stress for 5 days and examined for body weight, food intake, or plus-maze behavior. Social stress reduced food intake, body weight, and open-arm entries in 4-week-old but not 8-week-old mice. Restraint reduced body weight in 4-week-old but not 8-week-old mice. It is concluded that immature male mice show greater behavioral disturbances after stress than their mature counterparts. The findings are in agreement with much anecdotal evidence that children are more vulnerable to stress than adults.     

CBF beta-SMMHC, expressed in M4Eo AML, reduced CBF DNA-binding and inhibited the G1 to S cell cycle transition at the restriction point in myeloid and lymphoid cells

CBF beta-SMMHC is expressed from the inv(16) chromosome in M4Eo AML. Mice lacking CBF subunits or expressing the CBF beta-SMMHC or AML1-ETO oncoproteins failed to develop definitive hematopoiesis. To investigate these effects on hematopoiesis, we expressed CBF beta-SMMHC from the metallothionein promoter, in both 32D cl3 myeloid cells and Ba/F3 B-lymphoid cells. Addition of zinc increased CBF beta-SMMHC levels more than tenfold, with higher levels evident in Ba/F3 lines. Levels obtained in 32D cl3 cells were similar to those of endogenous CBF beta. Indirect immunofluorescence revealed zinc-inducible speckled, nuclear staining in Ba/F3 cells and diffuse nuclear staining in 32D cl3 cells. CBF beta-SMMHC reduced endogenous CBF DNA-binding fivefold in both cell types, increased cell generation time 1.9-fold, on average, in 32D cl3 cells and 1.5-fold in Ba/ F3 cells and decreased tritiated thymidine incorporation into DNA correspondingly. CBF beta-SMMHC increased the proportion of cells in G1 1.7-fold, on average, in 32D cl3 and Ba/F3 cells, and decreased the proportion of cells in S phase by a similar degree. CBF beta-SMMHC induced a marked increase in hypophosphorylated Rb, but did not alter IL-3 Receptor alpha or beta subunit levels. Neither apoptosis nor 32D differentiation was induced by zinc in IL-3 in these lines. Induction of CBF beta-SMMHC in 32D cl3 cells did not inhibit their differentiation to neutrophils or their expression of myeloperoxidase mRNA in G-CSF, and did not produce an eosinophilic phenotype. Additional, proliferative genetic changes in M4eo AMLs might potentiate inhibition of differentiation by CBF beta-SMMHC by allowing its increased expression.     

Playing with pets and longevity among older people.

Models of the relations between contact with pets and better health are examined in an archival prospective study using data derived from the longitudinal study initiated by Terman in 1921 (current N?=?343 men, 300 women) . In survival analyses of documented longevity, playing with pets in 1977 (M age?=?67 years) was not associated with mortality risk through 1991 for the total sample nor for those who were unmarried or those who were less satisfied with their human relationships. Playing with pets was not associated with health-prone attributes or healthy behaviors such as personality, social ties, education, and smoking. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The COMMIT dental model: tobacco control practices and attitudes

The National Cancer Institute's program to help dentists reduce tobacco use among their patients is part of the Community Intervention Trial for Smoking Cessation, a 22-community, randomly controlled trial of an intervention program for smoking cessation. Results of COMMIT baseline surveys of dentists in the 11 intervention communities are presented.     

Failure of Al-Mg-Si alloys in bending

The bendability of two Al-Mg-Si heat-treatable alloys was studied and compared with the performance of a non-heat-treatable Al-Mg alloy. A semi-guided wrap-bend tester consistent with ASTM E290 was used to obtain minimum bend radii and produce consistent bend radii for analysis of fracture mechanisms. Bending failure in these alloys was based on a surface roughening, or orange peel, process where the outer surface grains separated and produced depressions on the surface of the material. These depressions acted as notches that increased local stresses and eventually caused failure. The fracture was intergranular in nature, with a jagged crack progressing through the thickness of the material. Several factors that affect the bendability of AA6xxx alloys are quantified in this study. Critical elements regarding natural aging, artificial aging, deformation, and composition are discussed. A parameter of specific interest is the inclusion of copper in these alloys. Copper was added in an effort to increase the artificial aging response of selected alloys. This is of particular importance in the automotive industry because artificial aging occurs during the painting process, but adequate time and temperature is not provided to fully strengthen the alloys. It is believed by some automotive manufacturers that the inclusion of copper can have a negative effect on formability and bendability.