Using cognitive pre-testing methods in the development of a new evidenced-based pressure ulcer risk assessment instrument.

BACKGROUND: Variation in development methods of Pressure Ulcer Risk Assessment Instruments has led to inconsistent inclusion of risk factors and concerns about content validity. A new evidenced-based Risk Assessment Instrument, the Pressure Ulcer Risk Primary Or Secondary Evaluation Tool - PURPOSE-T was developed as part of a National Institute for Health Research (NIHR) funded Pressure Ulcer Research Programme (PURPOSE: RP-PG-0407-10056). This paper reports the pre-test phase to assess and improve PURPOSE-T acceptability, usability and confirm content validity. METHODS: A descriptive study incorporating cognitive pre-testing methods and integration of service user views was undertaken over 3 cycles comprising PURPOSE-T training, a focus group and one-to-one think-aloud interviews. Clinical nurses from 2 acute and 2 community NHS Trusts, were grouped according to job role. Focus group participants used 3 vignettes to complete PURPOSE-T assessments and then participated in the focus group. Think-aloud participants were interviewed during their completion of PURPOSE-T. After each pre-test cycle analysis was undertaken and adjustment/improvements made to PURPOSE-T in an iterative process. This incorporated the use of descriptive statistics for data completeness and decision rule compliance and directed content analysis for interview and focus group data. Data were collected April 2012-June 2012. RESULTS: Thirty-four nurses participated in 3 pre-test cycles. Data from 3 focus groups, 12 think-aloud interviews incorporating 101 PURPOSE-T assessments led to changes to improve instrument content and design, flow and format, decision support and item-specific wording. Acceptability and usability were demonstrated by improved data completion and appropriate risk pathway allocation. The pre-test also confirmed content validity with clinical nurses. CONCLUSIONS: The pre-test was an important step in the development of the preliminary PURPOSE-T and the methods used may have wider instrument development application. PURPOSE-T proposes a new approach to pressure ulcer risk assessment, incorporating a screening stage, the inclusion of skin status to distinguish between those who require primary prevention and those who require secondary prevention/treatment and the use of colour to support pathway allocation and decision making. Further clinical evaluation is planned to assess the reliability and validity of PURPOSE-T and it's impact on care processes and patient outcomes.

Tagging cortical networks in emotion: a topographical analysis.

Viewing emotional pictures is associated with heightened perception and attention, indexed by a relative increase in visual cortical activity. Visual cortical modulation by emotion is hypothesized to reflect re-entrant connectivity originating in higher-order cortical and/or limbic structures. The present study used dense-array electroencephalography and individual brain anatomy to investigate functional coupling between the visual cortex and other cortical areas during affective picture viewing. Participants viewed pleasant, neutral, and unpleasant pictures that flickered at a rate of 10 Hz to evoke steady-state visual evoked potentials (ssVEPs) in the EEG. The spectral power of ssVEPs was quantified using Fourier transform, and cortical sources were estimated using beamformer spatial filters based on individual structural magnetic resonance images. In addition to lower-tier visual cortex, a network of occipito-temporal and parietal (bilateral precuneus, inferior parietal lobules) structures showed enhanced ssVEP power when participants viewed emotional (either pleasant or unpleasant), compared to neutral pictures. Functional coupling during emotional processing was enhanced between the bilateral occipital poles and a network of temporal (left middle/inferior temporal gyrus), parietal (bilateral parietal lobules), and frontal (left middle/inferior frontal gyrus) structures. These results converge with findings from hemodynamic analyses of emotional picture viewing and suggest that viewing emotionally engaging stimuli is associated with the formation of functional links between visual cortex and the cortical regions underlying attention modulation and preparation for action.

Patients with surgical wounds healing by secondary intention: A prospective, cohort study.

BACKGROUND: Surgical wounds healing by secondary intention can be difficult and costly to manage and are profoundly under researched. This prospective inception, cohort study aimed to derive a better understanding of surgical wounds healing by secondary intention and to facilitate the design of future research investigating effective treatments. OBJECTIVES: To investigate the clinical characteristics of patients with surgical wounds healing by secondary intention and the surgeries that preceded their wounds; to clearly delineate the clinical outcomes of these patients, specifically focusing on time to wound healing and its determinants; to explore the types of treatments for surgical wounds healing by secondary intention; and to assess the impact surgical wounds healing by secondary intention have on patients' quality of life. DESIGN: Prospective, inception cohort study. SETTING: Acute and community settings in eight sites across two large centres in the United Kingdom (Hull and Leeds, UK). METHODS: Patients with a surgical wounds healing by secondary intention (an open wound, <3 weeks' duration, resulting from surgery), were recruited and followed up for at least 12 months. Key outcome events included: time to healing; treatment type; infection; hospital re-admission and further procedures; health-related quality of life and pain. RESULTS: In total, 393 patients were recruited. Common co-morbidities were cardiovascular disease (38%), diabetes (26%) and peripheral vascular disease (14.5%). Baseline median SWHSI area was 6 cm2 (range 0.01-1200). Abdominal (n = 132), foot (n = 59), leg (n = 58) and peri-anal (n = 34) wounds were common. The majority of wounds (236, 60.1%) were intentionally left open following surgery; the remainder were mostly dehisced wounds. Healing was observed in 320 (81.4%) wounds with a median time to healing of 86 days (95% CI: 75-130). Factors associated with delayed healing included wound infection at any point and baseline wound area above the median. Health-related quality of life scores were low at baseline but improved with time and healing. CONCLUSIONS: This is the first inception cohort study in patients with surgical wounds healing by secondary intention. Patient characteristics have been clearly defined, with prolonged healing times and adverse events being common impacting on patient's health-related quality of life. Areas for, and factors crucial to the design of, future research have been identified.

Pilot feasibility randomized clinical trial of negative-pressure wound therapy versus usual care in patients with surgical wounds healing by secondary intention.

BACKGROUND: Surgical wounds healing by secondary intention (SWHSI) are increasingly being treated with negative-pressure wound therapy (NPWT) despite a lack of high-quality research evidence regarding its clinical and cost-effectiveness. This pilot feasibility RCT aimed to assess the methods for and feasibility of conducting a future definitive RCT of NPWT for the treatment of SWHSI. METHODS: Eligible consenting adult patients receiving care at the study sites (2 acute and 1 community) and with a SWHSI appropriate for NPWT or wound dressing treatment were randomized 1 : 1 centrally to receive NPWT or usual care (no NPWT). Participants were followed up every 1-2 weeks for 3 months. Feasibility (recruitment rate, time to intervention delivery) and clinical (time to wound healing) outcomes were assessed. RESULTS: A total of 248 participants were screened for eligibility; 40 (16·1 per cent) were randomized, 19 to NPWT and 21 to usual care. Twenty-four of the 40 wounds were located on the foot. Participants received NPWT for a median of 18 (range 0-72) days. Two participants in the NPWT group never received the intervention and 14 received NPWT within 48 h of randomization. Five participants in the usual care group received NPWT during the study. Ten of the 40 wounds were deemed to have healed during the study. CONCLUSION: A full-scale RCT to investigate the clinical and cost-effectiveness of NPWT for SWHSI is feasible. This study identified crucial information on recruitment rates and data collection methods to consider during the design of a definitive RCT. Registration number: ISRCTN12761776 (http://www.iscrtn.com).

Involvement of deoxyribonuclease activity in the differential sedimentation rates of nucleoids from non-transformed and transformed mouse embryo fibroblasts.

Lysis of non-transformed confluent C3H10T1/2C18 mouse embryo fibroblasts in the presence of detergents, high concentrations of salt and EDTA on top of neutral sucrose gradients revealed a reduced sedimentation rate of the resulting nucleoids from these cells compared to those from exponentially growing non-transformed cells or from transformed cells. Exposure of confluent cells to 1000 rads of X-ray had no effect on this rate of nucleoid sedimentation; and ethidium bromide titration and alkaline sucrose analysis suggested the presence of discontinuities in the DNA. An endonucleolytic activity could be extracted from nuclei of these cells with 0.5 M NaCl, indicating a very tight association with the chromatin. Such an enzyme in non-transformed confluent cells may account for the differences in nucleoid structure and may be related to changes in cell function with normal arrest of cell growth. There was no growth-phase effect on the properties of nucleoids from transformed cells.

Selective processing of multiple features in the human brain: effects of feature type and salience.

Identifying targets in a stream of items at a given constant spatial location relies on selection of aspects such as color, shape, or texture. Such attended (target) features of a stimulus elicit a negative-going event-related brain potential (ERP), termed Selection Negativity (SN), which has been used as an index of selective feature processing. In two experiments, participants viewed a series of Gabor patches in which targets were defined as a specific combination of color, orientation, and shape. Distracters were composed of different combinations of color, orientation, and shape of the target stimulus. This design allows comparisons of items with and without specific target features. Consistent with previous ERP research, SN deflections extended between 160-300 ms. Data from the subsequent P3 component (300-450 ms post-stimulus) were also examined, and were regarded as an index of target processing. In Experiment A, predominant effects of target color on SN and P3 amplitudes were found, along with smaller ERP differences in response to variations of orientation and shape. Manipulating color to be less salient while enhancing the saliency of the orientation of the Gabor patch (Experiment B) led to delayed color selection and enhanced orientation selection. Topographical analyses suggested that the location of SN on the scalp reliably varies with the nature of the to-be-attended feature. No interference of non-target features on the SN was observed. These results suggest that target feature selection operates by means of electrocortical facilitation of feature-specific sensory processes, and that selective electrocortical facilitation is more effective when stimulus saliency is heightened.

Differential effects of DNA gyrase inhibitors on the genetic transformation of Neisseria gonorrhoeae.

Inhibitors of DNA gyrase in Escherichia coli exerted differential effects on the genetic transformation of Neisseria gonorrhoeae. When competent cells of the gonococcus were exposed to novobiocin before the uptake of transforming antibiotic resistance DNA, there was a 50 to 60% reduction in the number of transformants compared with the number of control untreated cells. Norfloxacin, a more potent inhibitor of DNA gyrase and an analog of nalidixic acid, nearly abolished the production of transformants by recipient cells. On the contrary, exposure of competent cells to nalidixic acid had no effect on transformant yield. The target of these inhibitors appears to be at the level of recombination. Possible mechanisms are discussed.

Regulation of synthesis of the aminoacyl-transfer ribonucleic acid synthetases for the branched-chain amino acids of Escherichia coli.

The regulation of synthesis of valyl-, leucyl-, and isoleucyl-transfer ribonucleic acid (tRNA) synthetases was examined in strains of Escherichia coli and Salmonella typhimurium. When valine and isoleucine were limiting growth, the rate of formation of valyl-tRNA synthetase was derepressed about sixfold; addition of these amino acids caused repression of synthesis of this enzyme. The rate of synthesis of the isoleucyl- and leucyl-tRNA synthetases was derepressed only during growth restriction by the cognate amino acid. Restoration of the respective amino acid to these derepressed cultures caused repression of synthesis of the aminoacyl-tRNA synthetase, despite the resumption of the wild-type growth rate.

Role of histidine transfer ribonucleic acid in regulation of synthesis of histidyl-transfer ribonucleic acid synthetase of Salmonella typhimurium.

The role of histidine transfer ribonucleic acid (tRNA) in repression of synthesis of histidyl-tRNA synthetase was examined in two strains of Salmonella typhimurium, one of which was a histidine tRNA (hisR) mutant possessing 52% of the wild-type (hisR(+)) histidine tRNA and a derepressed level of the histidine biosynthetic enzymes during histidine-unrestricted growth. Histidine-restricted growth caused a derepression of the rate of formation of histidyl-tRNA synthetase in both strains. In the case of the wild-type strain, addition of histidine to the derepressed culture caused a repression of synthesis of histidyl-tRNA synthetase for at least one generation of growth. In contrast, when histidine was restored to the derepressed hisR mutant culture, synthesis of histidyl-tRNA synthetase was continued at the initial derepressed rate. These results suggest that histidine must be attached to histidine tRNA for repression of synthesis of histidyl-tRNA synthetase.

Regulation of histidyl-transfer ribonucleic acid synthetase formation in a histidyl-transfer ribonucleic acid synthetase mutant of Salmonella typhimurium.

Control of formation of the histidyl-transfer ribonucleic acid (tRNA) synthetase with an increased K(m) for histidine was studied in a hisS mutant of Salmonella typhimurium. Histidine restriction of both the hisS and hisS(+) strains resulted in a derepression of synthesis of histidyl-tRNA synthetase. When grown in a concentration less than the K(m) (100 mug/ml) of l-histidine, the hisS mutant maintained a higher level of histidyl-tRNA synthetase than the hisS(+) strain. Addition of excess amounts of l-histidine to the growth medium of the hisS mutant culture grown with 100 mug of l-histidine per ml resulted in a repression of histidyl-tRNA synthetase formation to equal that of the hisS(+) strain grown in 100 mug of l-histidine per ml. These data confirm previous findings that histidine tRNA is involved in the repression of synthesis of histidyl-tRNA synthetase.

Derepression of synthesis of the aminoacyl-transfer ribonucleic acid synthetases for the branched-chain amino acids of Escherichia coli.

The kinetics of derepression of valyl-, isoleucyl-, and leucyl-transfer ribonucleic acid (tRNA) synthetase formation was examined during valine-, isoleucine-, and leucine-limited growth. When valine was limiting growth, valyl-tRNA synthetase formation was maximally derepressed within 5 min, whereas the rates of synthesis of isoleucyl-, and leucyl-tRNA synthetases were unchanged. Isoleucine-restricted growth caused a maximal derepression of isoleucyl-tRNA synthetase formation in 5 min and derepression of valyl-tRNA synthetase formation in 15 min with no effect on leucyl-tRNA synthetase formation. When leucine was limiting growth, leucyl-tRNA synthetase formation was immediately derepressed, whereas valyl- and isoleucyl-tRNA synthetase formation was unaffected by manipulation of the leucine supply to the cells. These results support our previous findings that valyl-tRNA synthetase formation is subject to multivalent repression control by both isoleucine and valine. In contrast, repression control of iso-leucyl- and leucyl-tRNA synthetase formation is specifically mediated by the supply of the cognate amino acid.

Control of arginine biosynthesis in Escherichia coli: inhibition of arginyl-transfer ribonucleic acid synthetase activity.

In this study, we have extended our earlier observations indicating in vitro inhibition of arginyl-transfer ribonucleic acid synthetase (EC 6.1.13, arginine: soluble ribonucleic acid ligase, adenosine monophosphate) activity by the arginine biosynthetic precursors ornithine, citrulline, and argininosuccinate. Furthermore, we report evidence which suggest that this enzyme activity is inhibited by these arginine precursors in vivo and that this inhibition of activity results in a derepression of arginine biosynthesis.

Evaluation of the relationship between PAH content and mutagenic activity of fumes from roofing and paving asphalts and coal tar pitch.

Fume condensates from asphalt and coal tar pitch were evaluated to determine if polycyclic aromatic hydrocarbon (PAH) composition, crude oil source, or temperature at which the fume was generated correlated with mutagenic activity. The fume condensates were tested for mutagenic activity using a modified Ames Test. Benzo[a]pyrene (BP) and other PAHs were detected in all samples. The concentration of BP in coal tar pitch was 18,100 ppm while the concentration in asphalt was less than 6 ppm. Coal tar fumes contained between two and three orders of magnitude more BP, as well as other PAH species, than asphalt fumes. Coal tar fume condensates were also approximately 100 times more mutagenic than those of asphalt. Generation temperature, crude oil source, and/or process conditions affected the PAH concentrations but not the mutagenicity in roofing asphalt fume condensates. With paving asphalt fumes, PAH content and mutagenicity varied with crude oil source but not with processing conditions; due to limited data, it was not possible to determine the effect of generation temperature. Coal tar pitch fumes generated at 316 degrees C contained significantly higher concentrations of PAHs than those generated at 232 degrees C and the mutagenic activity generally paralleled the PAH content. A subset of the paving asphalts demonstrated good correlation between mutagenicity and three- to seven-ring PAH content. These results indicate that asphalt fumes are far less mutagenic than coal tar fumes. Asphalt fumes differ in their ability to induce mutagenic activity, and, most likely, in their potential carcinogenicity.