pH titration of native and unfolded beta-trypsin: evaluation of the delta delta G0 titration and the carboxyl pK values

The stabilizing free energy of beta-trypsin was determined by hydrogen ion titration. In the pH range from 3.0 to 7.0, the change in free energy difference for the stabilization of the native protein relative to the unfolded one (delta delta G0 titration) was 9.51 +/- 0.06 kcal/mol. An isoelectric point of 10.0 was determined, allowing us to calculate the Tanford and Kirkwood electrostatic factor w. This factor presented a nonlinear behavior and indicated more than one type of titratable carboxyl groups in beta-trypsin. In fact, one class of carboxyl group with a pK = 3.91 +/- 0.01 and another one with a pK = 4.63 +/- 0.03 were also found by hydrogen ion titration of the protein in the folded state.     

Monocyte diapedesis through an in vitro vessel wall construct: inhibition with monoclonal antibodies to thrombospondin

Human peripheral blood monocytes were examined for migration across an endothelial cell monolayer in an in vitro vessel wall construct. Few monocytes invaded in the absence of a chemotactic gradient, despite significant adhesion to the endothelial monolayer. However, the addition of zymosan-activated human plasma to the lower compartment, to create a chemotactic gradient across the vessel wall, resulted in significantly enhanced monocyte migration. Pretreatment of the monocytes with monoclonal antibodies to thrombospondin (TSP) dramatically inhibited monocyte diapedesis into the vessel wall. The same treatment inhibited monocyte adhesion to endothelial cells in two-dimensional monolayer cultures as well as in vessel wall constructs (no chemotactic gradient). Of interest, however, the monoclonal antibodies had no inhibitory effect on monocyte migration into collagen gels devoid of endothelial cells in response to the same chemotactic gradient, suggesting the importance of TSP in monocyte-endothelial cell interactions. Monoclonal antibodies to fibronectin and normal mouse immunoglobulin G did not inhibit migration in this model of a vessel wall. Furthermore, monoclonal antibodies to TSP showed no inhibition of human peripheral blood neutrophil migration. Previous studies have shown that monocytes synthesize TSP and express this moiety on their surface. The present data suggest that monocytes may utilize TSP to interact with endothelial cells lining the vessel wall during diapedesis.     

Software tools for micro-analysis of programs

The paper proposes and describes several tools enabling their user to estimate the efficiency of Pascal or C-like programs. The approach consists of generating symbolic formulas expressing the efficiency of the programs being analyzed. The formulas are applicable to a variety of compiler-machine configurations. The actual numeric values of the variables in the symbolic formula are determined using linear programming techniques. The proposed approach reduces considerably the amount of benchmarking needed to analyze programs. Several examples are presented showing the applicability of the tools. The effort necessary to implement them is considerably reduced by the combined usage of Prolog and a symbolic formula manipulation package (Maple).     

Bimanual interference associated with the selection of target locations.

Four experiments were conducted to identify the locus of interference observed during the preparation of bimanual reaching movements. Target locations were specified by color, and the right-hand and left-hand targets could be either the same or a different color. Movements of different amplitudes (Experiment 1) or different directions (Experiment 2) to targets of the same color were initiated more quickly than symmetric movements to targets of different colors. These results indicate that costs observed during bimanual movements arise during target selection rather than during motor programming. Experiments 3 and 4 further examined the interference associated with target selection. Reaction time costs were found with unimanual movements when the target was presented among distractors associated with responses for the other hand. Interference observed during bimanual reaching appears to reflect difficulty in segregating the response rules assigned to each hand. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychosocial characteristics of adolescents who refuse cancer treatment.

Examined psychosocial variables by comparing 10 13–17 yr old adolescents (and their mothers) who had refused cancer treatment with a group of 10 consenting adolescents who were matched on age and demographic and illness variables. Adolescents completed the State-Trait Anxiety Inventory for Children and measures of family characteristics, locus of control, religion, hopelessness, impact of event, and satisfaction with physician. Mothers completed the State-Trait Anxiety Inventory and measures of coping and religion. Adolescent refusers scored lower on state anxiety and subjective distress but scored higher on trait anxiety, religiosity, and external locus of control. Their mothers also scored higher than did the consenting-group mothers on religiosity and trait anxiety. It is suggested that refusers are prone to anxiety and cope with their present distress by maintaining the belief that their lives are determined by fate or religious convictions. An intervention approach that fosters mastery over the cancer experience is advocated. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)