Metabolites from an Antarctic sponge-associated bacterium, Pseudomonas aeruginosa

In an ongoing survey of the bioactive potential of microorganisms associated with marine invertebrates, the culture media of a sponge-associated bacterial strain of Pseudomonas aeruginosa was found to contain metabolites which inhibit the growth of several Gram-positive microorganisms. A series of diketopiperazines (1-6) including a new natural product (6) and two known phenazine alkaloid antibiotics (7 and 8) were isolated from the culture broth of this bacterium.     

Central venous line sepsis in the intensive care unit. A study comparing antibiotic coated catheters with plain catheters

A randomized controlled clinical trial was undertaken to evaluate the efficacy of antibiotic bonded lines in the reduction of central venous catheter infection. One hundred and seventy-six plain and bonded catheters were inserted into one hundred and ten patients in an intensive care unit, many of whom were admitted with evidence of sepsis. The catheters used in the study group, which had been pre-treated by the manufacturers with the cationic surfactant tridodecylmethylammonium chloride, were bonded with vancomycin 1 g made up in 10 ml of water immediately prior to insertion. The catheters used in the control group were neither pre-treated nor bonded with vancomycin. Eighty percent of control group catheters were infected compared with 62% of study catheters (p = 0.01). The most common organism isolated was coagulase negative staphylococcus. We conclude that antibiotic bonding can reduce central venous catheter infection even in a patient population with a high incidence of sepsis.     

Multiple solution conformations of the integrin-binding cyclic pentapeptide cyclo(-Ser-D-Leu-Asp-Val-Pro-). Analysis of the (phi, psi) space available to cyclic pentapeptides

The aqueous solution structure of the cyclic pentapeptide cyclo(-Ser-D-Leu-Asp-Val-Pro-) has been determined by two-dimensional 1H-NMR spectroscopy, combined with a conformational search and distance-geometry calculations. As many as five conformers in slow exchange were observed, and the rate of interconversion between components was measured from the build-up rates of exchange peaks. NMR data allowed the structures of the two predominant conformers to be determined. The major component (66%) contained a cis-proline as part of a type-VIa2 beta-turn encompassing residues Asp-Val-cis-Pro-Ser. The second component (16%) contained only trans-amide bonds, and a type-VIII beta-turn formed by residues Val-Pro-Ser-D-Leu. These structures are discussed in relation to the (phi, psi), space available to the cyclic pentapeptide, determined by a conformational search, and in relation to previously published cyclic-pentapeptide structures. The molecule exhibits activity in a scintillation-proximity assay for the inhibition of the interaction between the integrin very-late antigen-4 (VLA-4; alpha 4 beta 1) and vascular-cell-adhesion molecule-1 (VCAM-1). The structure/activity relationship of the LDV sequence is discussed and related to the recently published X-ray structure of VCAM-1. The relevance of the work to the design of anti-inflammatory drugs is discussed.     

Sustained attention after severe closed head injury.

Sustained attention was assessed in 20 patients with severe closed head injury (CHI) and 20 normal matched controls. Participants were presented with a visual continuous performance task (CPT) with 3 levels of complexity. Performance was assessed by examining response latencies and error rates. Across all levels of complexity, the CHI patients demonstrated a vigilance decrement, whereas the performance of the matched controls was stable across time. The vigilance decrement was not differentially affected by the manipulation of task complexity in the CHI patients. However, findings suggest that the overall vigilance performance of CHI patients was differentially affected by increasing the complexity of the task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Meta-analysis of assessment center validity.

Meta-analysis (Hunter, Schmidt, & Jackson, 1982) of 50 assessment center studies containing 107 validity coefficients revealed a corrected mean and variance of .37 and .017, respectively. Validities were sorted into five categories of criteria and four categories of assessment purpose. Higher validities were found in studies in which potential ratings were the criterion, and lower validities were found in promotion studies. Sufficient variance remained after correcting for artifacts to justify searching for moderators. Validities were higher when the percentage of female assessees was high, when several evaluation devices were used, when assessors were psychologists rather than managers, when peer evaluation was used, and when the study was methodologically sound. Age of assessees, whether feedback was given, days of assessor training, days of observation, percentages of minority assessees, and criterion contamination did not moderate assessment center validities. The findings suggest that assessment centers show both validity generalization and situational specificity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A test of subliminal symbiotic activation as a means of alleviating depression.

Thirty-six depressive subjects were randomly assigned to one of three treatment groups. Group 1 subjects received 60 subliminal presentations of a slide of two figures and the words MOMMY AND I ARE ONE for male subjects and DADDY AND I ARE ONE for female subjects. Group 2 subjects received 60 subliminal slide presentations of a single figure with the words PEOPLE ARE WALKING. Group 3 subjects did not receive a slide. A pretest and posttest Beck Depression Inventory was administered to assess depression increase or decrease. The "subliminal" therapy was carried out over four different sessions. The data show that Group 1 subjects significantly reduced depression scores from pretest to posttest, whereas the subjects in Groups 2 and 3 did not reduce depression scores. Discussion is centered on comparisons of the data with past findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vacancy mediated substitutional diffusion in binary crystalline solids

We describe a formalism to predict diffusion coefficients of substitutional alloys from first principles. The focus is restricted to vacancy mediated diffusion in binary substitutional alloys. The approach relies on the evaluation of Kubo-Green expressions of kinetic-transport coefficients and fluctuation expressions of thermodynamic factors for a perfect crystal using Monte Carlo simulations applied to a cluster expansion of the configurational energy. We make a clear distinction between diffusion in a perfect crystal (i.e. no climbing dislocations and grain boundaries that can act as vacancy sources) and diffusion in a solid containing a continuous distribution of vacancy sources that regulate an equilibrium vacancy concentration throughout. A variety of useful metrics to characterize intermixing processes and net vacancy fluxes that can result in the Kirkendall effect are described and are analyzed in the context of thermodynamically ideal but kinetically non-ideal model alloys as well as a realistic thermodynamically non-ideal alloy. Based on continuum simulations of diffusion couples using self-consistent perfect-crystal diffusion coefficients, we show that the rate and mechanism of intermixing in kinetically non-ideal alloys is very sensitive to the density of discrete vacancy sources.