Decreased mobility, lack of social support, haemosiderosis and use of antidepressant medications may predict recurrent venous leg ulcers within 12 months of healing: A prospective longitudinal study.

AIM: To identify clinical, medical and psychosocial predictors of venous leg ulcer recurrence within 12 months of healing. METHODS: A multi-site study was conducted in Australia in community and hospital outpatient settings. Adults with venous leg ulcers were recruited within 4 weeks of healing and data were collected on preventative treatments and health, medical, clinical and psychosocial factors. Follow-up data on recurrences were collected every 3 months until ulcer recurrence, or until 12 months after healing pending which occurred first. Factors associated with time to recurrence were analysed using a Cox proportional hazards regression model. DESIGN: Secondary data analysis of a multi-site, prospective longitudinal study to validate a risk assessment tool for recurrence. RESULTS: A sample of 143 participants was recruited (51% male, Mage = 73 years, SD 13.6). Almost half (49.6%) had an ulcer recurrence within 12 months, with a mean time to ulcer recurrence of 37 weeks (SE 1.63, 95% CI 33.7-40.1). Factors measured at the time of healing that were significant independent predictors of recurrence were: prescribed antidepressant medications (p = .035), presence of haemosiderosis (p = .006), decreased mobility (longer sitting times) (p = .007) and lower social support scale scores (p = .002). Participants who wore compression systems providing 20 mmHg or higher for at least 5 days/week were less likely to recur, although not reaching statistical significance (p = .06). CONCLUSION: Results provide evidence that antidepressant medications, haemosiderosis, decreased mobility and lack of social support are risk factors associated with ulcer recurrence; therefore, these variables are modifiable and could guide early intervention.

An exploration of knowledge of students and staff at residential aged care facilities and implications for nursing education.

BACKGROUND: Advances in healthcare have contributed to population longevity with many older adults living with complex comorbidities, including those in residential aged care facilities (RACFs). Nursing staff require knowledge of gerontology, normal ageing processes and expected physiological, psychosocial, function and cognitive changes in addition to health promotion in order to provide individualised care. The complexity inherent in the medical, palliative and basic care needs of the residents makes RACFs excellent places for learning for undergraduate student nurses who undertake clinical placement as part of a Bachelor of Nursing course. Previous research has identified that knowledge of care staff is relatively poor. OBJECTIVES: To explore the knowledge and misconceptions of ageing among first year undergraduate nursing students and aged care staff facilitating a placement during a clinical learning experience. DESIGN: Descriptive cross-sectional design. SETTING: Three clinical RACFs in Australia. PARTICIPANTS: First year nursing students and staff of three different RACFs. METHOD: Pre and post-test clinical placement surveys. Students and staff completed Palmore's Facts on Ageing Quiz, a 25-item tool to assess knowledge and attitudes of ageing, before commencing the clinical placement and on the last day of a two week placement. RESULTS: Physiological questions were answered correctly. A knowledge deficit was evident from a sociological perspective. Negative attitudes have been found to devalue care and can directly affect the quality of practice in an undesirable way, forming a barrier to effective and therapeutic relationships with older adults, potentially impacting on patient care. CONCLUSIONS: From an education provider perspective, the inclusion of activities to enrich the learning activities of nurses within RACF- inclusive of reflective activities and guidance from an expert clinical facilitator - may assist in dispelling negative attitudes and stereotypes of the older adult and increase recognition of the value of working with older adults.

Ulcer area reduction at 2 weeks predicts failure to heal by 24 weeks in the venous leg ulcers of patients living alone.

OBJECTIVE: Chronic wounds are costly and affect approximately 1-2% of the population. Venous disease is responsible for about 60% of all chronic leg ulcers and these ulcers can be debilitating, with evidence of a decreased quality of life. Unfortunately, up to 30% of venous leg ulcers (VLUs) fail to heal, despite best practice treatment. This study aimed to identify risk factors associated with delayed healing in participants with VLUs and in particular, whether psychosocial factors play a part in this process. METHOD: A secondary analysis was conducted of a large data set of clinical, wound healing, health, social, economic and psychological data collected in previous prospective studies of participants with VLUs. Generalised linear mixed modelling was used to identify independent predictors of failure to heal after 24 weeks. RESULTS: We recruited 247 participants with 318 VLUs from hospital and community settings. Findings revealed that four early predictors were independently significantly associated with failure to heal by 24 weeks. These were: participants who lived alone (OR 2.3, 95%CI [1.13-4.61], p=0.03); had less than 25% reduction in ulcer area within two weeks of treatment (OR 10.07, 95%CI [4.60-22.19], p<0.001); had higher ulcer severity scores (OR 5.1, 95%CI [2.33-11.88], p=0.001); and participants who were not treated with high level compression therapy (i.e.>30 mmHg) at the time of assessment (OR 4.18, 95% CI [1.95-8.97], p=0.002). CONCLUSION: Identified risk factors offer an opportunity for clinicians to determine realistic outcomes for their patients and to guide decisions on early referral and implementation of tailored adjunctive interventions. Additionally, findings from this study suggest health professionals need to assess and address not only clinical risk factors but also social risk factors, when planning interventions to promote healing.

Activation of Yap-Directed Transcription by Knockdown of Conserved Cellular Functions.

The Yap-Hippo pathway has a significant role in regulating cell proliferation and growth, thus controlling organ size and regeneration. The Hippo pathway regulates two highly conserved, transcription coactivators, YAP and TAZ. The upstream regulators of the Yap-Hippo pathway have not been fully characterized. The aim of this study was to use a siRNA screen, in a liver biliary cell line, to identify regulators of the Yap-Hippo pathway that allow activation of the YAP transcription coactivator at high cell density. Activation of the YAP transcription coactivator was monitored using a high-content, image-based assay that measured the intracellular localization of native YAP protein. Active siRNAs were identified and further validated by quantification of CYR61 mRNA levels (a known YAP target gene). The effect of compounds targeting the putative gene targets identified as hits was also used for further validation. A number of validated hits reveal basic aspects of Yap-Hippo biology, such as components of the nuclear pore, by which YAP cytoplasmic-nuclear shuttling occurs, or how proteasomal degradation regulates intracellular YAP concentrations, which then alter YAP localization and transcription. Such results highlight how targeting conserved cellular functions can lead to validated activity in phenotypic assays.

Risk factors for delayed healing in venous leg ulcers: a review of the literature.

BACKGROUND: Chronic leg ulcers, remaining unhealed after 4-6 weeks, affect 1-3% of the population, with treatment costly and health service resource intensive. Venous disease contributes to approximately 70% of all chronic leg ulcers and these ulcers are often associated with pain, reduced mobility and a decreased quality of life. Despite evidence-based care, 30% of these ulcers are unlikely to heal within a 24-week period and therefore the recognition and identification of risk factors for delayed healing of venous leg ulcers would be beneficial. AIM: To review the available evidence on risk factors for delayed healing of venous leg ulcers. METHODS: A review of the literature in regard to risk factors for delayed healing in venous leg ulcers was conducted from January 2000 to December 2013. Evidence was sourced through searches of relevant databases and websites for resources addressing risk factors for delayed healing in venous leg ulcers specifically. RESULTS: Twenty-seven studies, of mostly low-level evidence (Level III and IV), identified risk factors associated with delayed healing. Risk factors that were consistently identified included: larger ulcer area, longer ulcer duration, a previous history of ulceration, venous abnormalities and lack of high compression. Additional potential predictors with inconsistent or varying evidence to support their influence on delayed healing of venous leg ulcers included: decreased mobility and/or ankle range of movement, poor nutrition and increased age. DISCUSSION: Findings from this review indicate that a number of physiological risk factors are associated with delayed healing in venous leg ulcers and that social and/or psychological risk factors should also be considered and examined further. CONCLUSION: The findings from this review can assist health professionals to identify prognostic indicators or risk factors significantly associated with delayed healing in venous leg ulcers. This will facilitate realistic outcome planning and inform implementation of appropriate early strategies to promote healing.

Inhibition of bacterial IF2 binding to fMet-tRNA((fMet)) by aminoglycosides.

Screening for inhibitors of bacterial protein synthesis Initiation Factor 2 (IF2) binding to N-formyl-Methionyl-transfer RNA (fMet-tRNA((fMet))) identified a series of aminoglycosides, that included amikacin and kanamycin A1, as inhibitors of this interaction. Subsequent testing revealed that aminoglycosides displayed a wide range of inhibitory activity. However, the failure of these compounds to completely inhibit binding of IF2 to fMet-tRNA((fMet)), the known ability of aminoglycosides to bind RNA, and the ability of the aminoglycosides to displace PicoGreen bound to fMet-tRNA((fMet)) suggest these compounds act by binding fMet-tRNA((fMet)). This hypothesis is further supported by isothermal denaturation experiments that failed to show any interaction between the IF2 protein and the aminoglycosides.

The identification and characterization of hydrazinyl urea-based antibacterial agents through combinatorial chemistry.

An effort to identify novel inhibitors of peptidoglycan synthesis with antibacterial activity resulted in the discovery of a series of biaryl urea-based antibacterial agents through isolation of a by-product from a mixture-based combinatorial library of semi-carbazones and subsequent parallel synthesis efforts. The compounds were shown to possess broad spectrum antibacterial activity against gram-positive drug resistant pathogens, and showed apparent specificity for disruption of the bacterial cell wall biosynthesis pathway.

Application of nearest-neighbor and cluster analyses in pharmaceutical lead discovery.

High throughput screening (HTS) programs based on diverse collections of compounds can rapidly identify leads for potential drug candidates. In cases where the compound collection is truly diverse, one may only identify a few compounds of interest. However, where a large number of hits are identified, it becomes necessary to examine the structures to determine the true number of compound classes involved so that follow-up studies may be conducted as efficiently as possible. In this case, cluster analysis is applied to determine the structural relationship among HTS hits. To efficiently expand around the region of the hit (or a class of hits) in chemical space, we have applied nearest neighbors analysis to select additional compounds from collections of a large number of commercial vendors, achieving an average hit rate in excess of 15%. Applying these techniques in a number of different cases, we obtained results that are useful for subsequent investigations of hits from HTS and other relevant molecular structures from the literature.

Use of combinatorial library screening to identify inhibitors of a bacterial two-component signal transduction kinase.

Bacterial resistance to antibiotics is emerging as a major concern to the medical community. The appearance of several antibiotic-resistant strains, including multidrug-resistant Staphylococcus aureus, raises the prospect that infections by these bacteria could soon become untreatable with currently available antibiotics. In order to address this problem, increased emphasis is being placed on the discovery of novel classes of antibacterial agents that inhibit novel molecular targets using sources of compounds not yet exploited for antibiotic drug discovery. Novel classes of compounds can now be rapidly investigated using combinatorial chemistry approaches. This report describes the identification of novel antibacterial compounds from a combinatorial library of N-acetylated, C-amidated D-amino acid hexapeptides. This library of compounds was screened for inhibitors of CheA, a member of the bacterial two-component signal transduction kinase family. Several peptides with apparent IC50 values in the low micromolar range were identified. In addition to inhibiting CheA, these peptides inhibited mammalian protein kinase C (from rat brain) with comparable potency. Finally, these peptides were also found to have significant antibacterial properties, although the true mechanism by which they exhibited inhibition of bacterial growth remains uncertain.

Stereoselectivity of DNA catenane fusion by resolvase.

Communications between distant sites on DNA often depend on the way in which the sites are connected. For example, site-specific recombination catalysed by Tn3 resolvase is most efficient when the 114-base-pair res recombination sites are directly repeated in the same DNA molecule. In vitro a supercoiled plasmid substrate containing two directly repeated res sites gives a resolution product in which the two recombinant circles are topologically linked as a simple (two-noded) catenane (Fig. 1a). Resolvase is highly selective in forming this product rather than unlinked circles or more complex catenanes. It does not catalyse recombination between sites on separate supercoiled molecules, or between inverted sites in the same supercoiled molecule. Tn3 resolution removes four negative supercoils from the substrate, an energetically favourable change which may drive the reaction: in relaxed or nicked circular substrates, resolution is incomplete and slower. Resolvase can catalyse fusion of the circles of a nicked or relaxed catenane, giving a single unknotted circular product. The fusion is the precise topological reversal of resolution, introducing four negative supercoils into a relaxed catenane substrate, and should therefore not proceed if the catenane is already negatively supercoiled. Here we study recombination between res sites in non-supercoiled DNA circles linked into simple catenanes. We used (+2) and (-2) catenanes, which differ only in the direction in which one circle is threaded through the other (Fig. 2a). Although stereoselectivity is a feature of enzyme catalysis, it is not obvious how resolvase can distinguish between these subtly different catenane diastereomers. A model for the intertwining of the res site DNA in the catalytically active complex predicts that only the (-2) catenane will recombine, giving unknotted and 4-noded knot circular products. We have confirmed this prediction for the Tn3 and Tn21 resolvases.

Dynamics of long-range interactions on DNA: the speed of synapsis during site-specific recombination by resolvase.

A noninvasive method for monitoring communications on DNA was developed from the specificity of resolvase for the arrangement of its recombinational sites. Constraints in DNA structure, caused by interactions between distant sites, can be detected by resolvase as they arise. The method was used to follow the formation and decay of synaptic intermediates during site-specific recombination by resolvase. Synaptic complexes were formed very rapidly, at a rate limited by the initial association of the protein with DNA rather than the physical motion of DNA segments. The recombinational sites seem to encounter each other by an ordered motion, perhaps dictated by DNA supercoiling instead of random collisions, so that the first encounter produces the active complex.

Site-specific recombination by mutants of Tn21 resolvase with DNA recognition functions from Tn3 resolvase.

The resolvases from the transposons Tn3 and Tn21 are homologous proteins but they possess distinct specificities for the DNA sequence at their respective res sites. The DNA binding domain of resolvase contains an amino acid sequence that can be aligned with the helix-turn-helix motif of other DNA binding proteins. Mutations in the gene for Tn21 resolvase were made by replacing the section of DNA that codes for the helix-turn-helix with synthetic oligonucleotides. Each mutation substituted one amino acid in Tn21 resolvase with either the corresponding residue from Tn3 resolvase or a residue that lacks hydrogen bonding functions. The ability of these proteins to mediate recombination between res sites from either Tn21 or Tn3 was measured in vivo and in vitro. With one exception, where a glutamate residue had been replaced by leucine, the activity of these mutants was similar to that of wild-type Tn21 resolvase. A further mutation was made in which the complete recognition helix of Tn21 resolvase was replaced with that from Tn3 resolvase. This protein retained activity in recombining Tn21 res sites, though at a reduced level relative to wild-type; the reduction can be assigned entirely to weakened binding to this DNA. Neither this mutant nor any other derivative of Tn21 resolvase had any detectable activity for recombination between res sites from Tn3. The exchange of this section of amino acid sequence between the two resolvases is therefore insufficient to alter the DNA sequence specificity for recombination.