Age-related differences in the temporal and spatial regulation of matrix metalloproteinases (MMPs) in normal skin and acute cutaneous wounds of healthy humans

Despite the association of increasing age with chronic wound-healing disorders and an impaired rate of healing of acute cutaneous wounds, the role of matrix metalloproteinases (MMPs) is unknown. To determine the spatial and temporal patterns and activities of MMP-1, -2, -3 and -9, 132 healthy humans aged between 19 and 96 years underwent 4-mm punch biopsies followed by wound excision between day 1 and day 180 post-wounding. Wounds showed an age-related increase in MMP-2 and MMP-9 immunostaining from day 3; this was associated with degradation of gelatin as shown by zymograms and with increased proteinase activity as shown by azocoll assays. Distinct spatial localisations for each MMP were observed: MMP-2 was found in epidermal structures; MMP-9 was observed in inflammatory cells up to day 21; MMP-1 was localised to keratinocytes at the wound margin. Normal old skin showed pro-MMP-2 bands on zymography and increased MMP-2 immunostaining. These results indicate that: (1) intrinsic ageing is associated with the up-regulation of MMPs previously associated with chronic wound healing; (2) wound-tissue proteinases are essentially active up to day 21 postwounding; and (3) intrinsic ageing may predispose to tissue breakdown disorders because of MMP-2 up-regulation in normal skin.     

Topoisomerase function during replication-independent chromatin assembly in yeast

DNA topoisomerases I and II are the two major nuclear enzymes capable of relieving torsional strain in DNA. Of these enzymes, topoisomerase I plays the dominant role in relieving torsional strain during chromatin assembly in cell extracts from oocytes, eggs, and early embryos. We tested if the topoisomerases are used differentially during chromatin assembly in Saccharomyces cerevisiae by a combined biochemical and pharmacological approach. As measured by plasmid supercoiling, nucleosome deposition is severely impaired in assembly extracts from a yeast mutant with no topoisomerase I and a temperature-sensitive form of topoisomerase II (strain top1-top2). Expression of wild-type topoisomerase II in strain top1-top2 fully restored assembly-driven supercoiling, and assembly was equally efficient in extracts from strains expressing either topoisomerase I or II alone. Supercoiling in top1-top2 extract was rescued by adding back either purified topoisomerase I or II. Using the topoisomerase II poison VP-16, we show that topoisomerase II activity during chromatin assembly is the same in the presence and absence of topoisomerase I. We conclude that both topoisomerases I and II can provide the DNA relaxation activity required for efficient chromatin assembly in mitotically cycling yeast cells.     

Effects of irrelevant stimulus orientation on visually guided grasping movements.

The present study investigated the effects of irrelevant stimulus orientation on visually guided grasping movements. Participants had to grasp a rectangular object at either the ends or the sides, depending on the color of a visual stimulus. In this task, correspondence between stimulus orientation and object orientation (stimulus-object congruency) and correspondence between stimulus orientation and hand orientation (stimulus-hand congruency) varied independently. Two experiments, with different sets of object orientations, revealed a consistent pattern of results. In particular, there were significant effects of stimulus-hand congruency, suggesting that perceiving an object activates congruently oriented hand movements. However, stimulus-object congruency had no effects, indicating that participants did not benefit from a preactivation of object orientation in the present task. The pattern of congruency effects implies that the cognitive representation, which is affected by irrelevant visual information, entails only those object or response features that are needed to select and control a response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of self-reported and observed job conditions on depression and anxiety symptoms: A comparison of theoretical models.

The demand/control/support and effort/reward imbalance models have relied on self-reported methods to describe how poor psychosocial working conditions lead to harmful health outcomes. The hindrance/utilization model uses an observational methodology to assess these relationships. Cross-sectional observational and self-reported data from 98 civil servants participating in the Whitehall II Study of British civil servants were used to test whether work conditions measured by each of the three theoretical models explained a significant amount of the variance in depression and anxiety symptoms. Observational measures were also used to assess potential common methods variance bias between the self-reported job conditions and the outcomes. Results showed that the demand/control/support model explained the most variance in depression and anxiety symptoms and the associations were not wholly due to common methods variance. Moreover, measures associated with job resources (e.g., skill discretion, social support and skill utilization) had a protective effect on depression and anxiety symptoms. Exertion-related conditions (e.g., demands, effort, over commitment) were not consistently associated with depression or anxiety symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ribonuclease A variants with potent cytotoxic activity

Select members of the bovine pancreatic ribonuclease A (RNase A) superfamily are potent cytotoxins. These cytotoxic ribonucleases enter the cytosol, where they degrade cellular RNA and cause cell death. Ribonuclease inhibitor (RI), a cytosolic protein, binds to members of the RNase A superfamily with inhibition constants that span 10 orders of magnitude. Here, we show that the affinity of a ribonuclease for RI plays an integral role in defining the potency of a cytotoxic ribonuclease. RNase A is not cytotoxic and binds RI with high affinity. Onconase, a cytotoxic RNase A homolog, binds RI with low affinity. To disrupt the RI-RNase A interaction, three RNase A residues (Asp-38, Gly-88, and Ala-109) that form multiple contacts with RI were replaced with arginine. Replacing Asp-38 and Ala-109 with an arginine residue has no effect on the RI-RNase interaction. In addition, these variants are not cytotoxic. In contrast, replacing Gly-88 with an arginine residue yields a ribonuclease (G88R RNase A) that retains catalytic activity in the presence of RI and is cytotoxic to a transformed cell line. Replacing Gly-88 with aspartate also yields a ribonuclease (G88D RNase A) with a decreased affinity for RI and cytotoxic activity. The cytotoxic potency of onconase, G88R RNase A, and G88D RNase A correlate with RI evasion. We conclude that ribonucleases that retain catalytic activity in the presence of RI are cytotoxins. This finding portends the development of a class of chemotherapeutic agents based on pancreatic ribonucleases.     

3D Micro-PIXE at atmospheric pressure: A new tool for the investigation of art and archaeological objects

The paper describes a novel experiment characterized by the development of a confocal geometry in an external Micro-PIXE set-up. The position of X-ray optics in front of the X-ray detector and its proper alignment with respect to the proton micro-beam focus provided the possibility of carrying out 3D Micro-PIXE analysis. As a first application, depth intensity profiles of the major elements that compose the patina layer of a quaternary bronze alloy were measured. A simulation approach of the 3D Micro-PIXE data deduced elemental concentration profiles in rather good agreement with corresponding results obtained by electron probe micro-analysis from a cross-sectioned patina sample. With its non-destructive and depth-resolving properties, as well as its feasibility in atmospheric pressure, 3D Micro-PIXE seems especially suited for investigations in the field of cultural heritage.     

CVT-313, a specific and potent inhibitor of CDK2 that prevents neointimal proliferation

The activity of cyclin-dependent kinase 2 (CDK2) is essential for progression of cells from G1 to the S phase of the mammalian cell cycle. CVT-313 is a potent CDK2 inhibitor, which was identified from a purine analog library with an IC50 of 0.5 microM in vitro. Inhibition was competitive with respect to ATP (Ki = 95 nM), and selective CVT-313 had no effect on other, nonrelated ATP-dependent serine/threonine kinases. When added to CDK1 or CDK4, a 8.5- and 430-fold higher concentration of CVT-313 was required for half-maximal inhibition of the enzyme activity. In cells exposed to CVT-313, hyperphosphorylation of the retinoblastoma gene product was inhibited, and progression through the cell cycle was arrested at the G1/S boundary. The growth of mouse, rat, and human cells in culture was also inhibited by CVT-313 with the IC50 for growth arrest ranging from 1.25 to 20 microM. To evaluate the effects of CVT-313 in vivo, we tested this agent in a rat carotid artery model of restenosis. A brief intraluminal exposure of CVT-313 to a denuded rat carotid artery resulted in more than 80% inhibition of neointima formation. These observations suggest that CVT-313 is a promising candidate for evaluation in other disease models related to aberrant cell proliferation.     

Psychometric properties of the Questionnaire on Stress in patients with Diabetes—Revised (QSD-R).

This study reports the psychometric properties of a 45-item diabetes-specific questionnaire, the Questionnaire on Stress in Patients with Diabetes—Revised (QSD-R), a modified and shortened version of the QSD (G. Duran et al; see record 1996-18805-001). The QSD-R was filled out by 1,930 individuals with insulin-dependent diabetes mellitus and noninsulin-dependent diabetes mellitus. Eight consistent scales were identified (values of Cronbach's α: .69–.81). The test-retest reliability for the total score after a 5-week interval was rtt?=?.63. The results provide evidence for the reliability and validity of this instrument. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social skills training for withdrawn unpopular children with physical disabilities: A preliminary evaluation.

Examined changes in self-concept, perceptions of support from close friends and classmates, and loneliness in 11 8.6–14.6 yr old withdrawn unpopular children with cerebral palsy or spina bifida who had been involved in a social skills training program. The program targeted 5 basic skills: interpersonal problem solving, verbal and nonverbal communication, initiating interactions with peers, conversational skills, and coping with difficult others. To assess the impact of the program, Ss were evaluated before the intervention, after the 10-wk intervention, and at a 6-mo follow-up. Findings indicate that group social skills training may be effective in decreasing feelings of loneliness and increasing perceptions of social acceptance in children who are withdrawn and unpopular at school. Ss' feelings of loneliness were associated with lower ratings of social acceptance and lower ratings of classmate support. (PsycINFO Database Record (c) 2010 APA, all rights reserved)