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PubMed2002

Solid-phase library synthesis, screening, and selection of tight-binding reduced peptide bond inhibitors of a recombinant Leishmania mexicana cysteine protease B.

A one-bead-two-compound inhibitor library was synthesized by the split-mix method for the identification of inhibitors of a recombinant cysteine protease from Leishmania mexicana, CPB2.8DeltaCTE. The inhibitor library was composed of octapeptides with a centrally located reduced bond introduced by reductive amination of the resin-bound amines with Fmoc amino aldehydes. The library was screened on solid phase, and less than 1% of the library contained active compounds. The inhibitors displayed great specificity in the subsites flanking the enzyme catalytic triad with Cha and Ile/Leu preferred in P(2), Phe in P(1), Cha and Ile/Leu in P(1)', and Ile/Leu in P(2)'. Some of the inhibitors were resynthesized, and the kinetics of inhibition were determined in solution-phase assays. Most of the inhibitors had micromolar K(i) values, and a few inhibited the enzyme at nanomolar concentrations. One inhibitor, DKHF(CH(2)NH)LLVK (K(i) = 1 microm), was tested for antiparasite efficacy and shown to affect parasite survival with an IC(50) of approximately 50 microm.

Amination↗

PubMed1989

Formulation of vaccine adjuvant muramyldipeptides. 3. Processing optimization, characterization, and bioactivity of an emulsion vehicle.

An efficacious vaccine adjuvant which elicits both cell-mediated immunity (CMI) and humoral immune response was developed using [thr1]-Muramyldipeptide (MDP) in an oil-in-water emulsion vehicle containing poloxamer 401, polysorbate 80, and squalane. Processing optimization was performed to increase the physical stability of this adjuvant emulsion which, when prepared by conventional mixing methods, demonstrated good bioactivity but poor physical stability. Various manufacturing methods were compared with a microfluidization process, which produced the most stable and elegant emulsion vehicle. The microfluidized emulsion also elicited equivalent biological response in the animal model tested.

Acetylmuramyl-Alanyl-Isoglutamine↗

PubMed2004

Quality of life in spinal cord injured individuals and their caregivers during the initial 6 months following rehabilitation.

Addressing quality of life (QOL) issues in the spinal cord injured (SCI) population is imperative as the majority survive their initial injury and longevity now approaches that of the general population. The purpose of this mixed method, descriptive, longitudinal feasibility study was to describe and compare QOL in 10 adult SCI individuals and their family caregivers (FCs) during the initial 6 months following rehabilitation. Instruments used were the SF-36 and two horizontal visual analog scales, one for pain and one for QOL. Participants completed the instruments and a face-to-face in-depth interview at 1-, 3-, and 6-months following inpatient rehabilitation. SCI individuals reported low physical function, role physical (RP), and role emotional (RE) scores on the SF-36, while reporting high general health (GH), mental health and social functioning on the SF-36. FCs reported lower RP, GH and vitality scores, while reporting higher physical functioning and RE scores. On the visual analog scales, persons with SCI reported lower QOL while FCs reported more pain at 3 and 6 months. This study suggests that more work is needed to identify interventions which could enhance QOL during the transition from rehabilitation to home for SCI individuals and their FCs.

Adult↗

PubMed1988

Font regularity constraints on the process of letter recognition.

Strings of four unrelated letters were presented for subjects to identify, followed by a patterned mask and then a forced choice test of each letter position. In Experiment 1, the type style in the regular conditions was consistent--all of the letters were of a single type font--whereas in the mixed condition, each string contained letters from two type fonts. Compared with the mixed condition, accuracy in the regular conditions was higher overall and increased at a faster rate as a function of processing time. This held across four sessions. In Experiment 2, the font in the mixed condition was varied either between or within letter strings; sizeable advantages for the regular conditions were found with both mix-methods. The results are consistent with the idea of a schemalike perceptual system that becomes tuned to the regularities of a particular font in order to process visual information efficiently.

Adult↗

PubMed2002

Exposure to human tragedy, empathy, and trauma in ambulance paramedics.

Paramedics are exposed to events involving human pain and suffering on a daily basis, many of which are the result of violence perpetrated by 1 individual on another. For the most part, these emergency workers have learned to deal with such events and take them in stride. At times, however, certain circumstances lead workers to develop an emotional connection with the victim or his or her family. When this occurs, paramedics report increased symptoms of traumatic stress. Aspects that can trigger this connection include the victim's alienation from others, profound loss, or the abuse of an innocent child. One of the coping strategies described in these circumstances is to manage the events on a cognitive and technical level while maintaining an emotional distance. Although such a strategy may be protective, it may also have long-term negative effects in terms of interpersonal relationships. This mixed-methods study attempts to better understand factors that lead to higher levels of distress among paramedics within the theoretical framework of emotional and cognitive empathy.

Adaptation, Psychological↗

PubMed2006

The Afghan symptom checklist: a culturally grounded approach to mental health assessment in a conflict zone.

This article describes a methodology for developing culturally grounded assessment measures in conflict and postconflict situations. A mixed-method design was used in Kabul, Afghanistan, to identify local indicators of distress and develop the 22-item Afghan Symptom Checklist (ASCL). The ASCL contains several indigenous items and items familiar to Western mental health professionals. The ASCL was pilot tested and subsequently administered to 324 adults in 8 districts of Kabul. It demonstrated excellent reliability (alpha=.93) and good construct validity, correlating strongly with a measure of exposure to war-related violence and loss (r=.70). Results of the survey indicate moderate levels of distress among Afghan men and markedly higher levels of distress and impaired functioning among women (and widows in particular).

Adult↗

PubMed1999

Folding dynamics of the B1 domain of protein G explored by ultrarapid mixing.

For many proteins, compact conformations are known to accumulate in advance of the rate-limiting step in folding. To understand the nature and significance of these early conformational events, we employed ultrarapid mixing methods to fully characterize the kinetics of folding of the 57-residue B1 domain of protein G. Continuous-flow fluorescence measurements exhibit a major exponential phase on the submillisecond time scale (600-700 micros), which is followed by a slower phase with a denaturant-dependent time constant (2-30 ms) observable by conventional stopped-flow measurements. The combined kinetic traces quantitatively account for the total change in Trp 43 fluorescence upon folding, including the previously unresolved 'burst phase' signal. The denaturant dependence of the two rate constants and their relative amplitudes are fully consistent with a three-state mechanism, U right harpoon over left harpoon I right harpoon over left harpoon N, where I is a productive intermediate with native-like fluorescence properties. The relatively slow rate and exponential time course of the initial folding phase indicates that a substantial free energy barrier is encountered during chain condensation, resulting in a partially organized ensemble of states distinct from the initial unfolded conformations.

Fluorescence↗

PubMed2002

Ultra rapid prototyping of microfluidic systems using liquid phase photopolymerization.

We present a method for the ultra rapid prototyping of microfluidic systems using liquid phase photopolymerization, requiring less than 5 min from design to prototype. Microfluidic device fabrication is demonstrated in a universal plastic or glass cartridge. The method consists of the following steps: introduction of liquid prepolymer into the cartridge, UV exposure through a mask to define the channel geometry, removal of unpolymerized prepolymer, and a final rinse. Rapidly fabricated masters for polydimethylsiloxane micromolding are also demonstrated. The master making process is compared to SU-8 50 photoresist processes. Press-on connectors are developed and demonstrated. All materials used are commercially available and low cost. An extension of these methods (mix and match) is presented that allows for maximal design flexibility and integration with a variety of existing fluidic geometries, components, and processes.

Journal Article↗

PubMed2003

Design of passive mixers utilizing microfluidic self-circulation in the mixing chamber.

This paper proposes the design of a passive micromixer that utilizes the self-circulation of the fluid in the mixing chamber for applications in the Micro Total Analysis Systems (microTAS). The micromixer with a total volume of about 20 microL and consisting of an inlet port, a circular mixing chamber and an outlet port was designed. The device was actuated by a pneumatic pump to induce self-circulation of the fluid. The self-circulation phenomenon in the micromixer was predicted by the computational simulation of the microfluidic dynamics. Flow visualization with fluorescence tracer was used to verify the numerical simulations and indicated that the simulated and the experimental results were in good agreement. Besides, an index for quantifying the mixing performance was employed to compare different situations and to demonstrate the advantages of the self-circulation mixer. The mixing efficiencies in the mixer under different Reynolds numbers (Re) were evaluated numerically. The numerical results revealed that the mixing efficiency of the mixer with self-circulation was 1.7 to 2 times higher than that of the straight channel without a mixing chamber at Re= 150. When Re was as low as 50, the mixing efficiency of the mixer with self-circulation in the mixing chamber was improved approximately 30% higher than that in the straight channel. The results indicated that the self-circulation in the mixer could enhance the mixing even at low Re. The features of simple mixing method and fabrication process make this micromixer ideally suitable for microTAS applications.

Journal Article↗

PubMed1990

Kinetics of ligand binding to haemoproteins.

A mass of experimental data has been accumulated in the 65 years since Hartridge and Roughton made the first measurement of the rapid reaction of haemoglobin with O2 in solution on a millisecond time scale, at first by flow-mixing methods, and, for 30 years or so, by flash photolysis. Technical advances, particularly in lasers, have allowed increasingly rapid reactions to be followed and the fastest reactions now observed have half-times conveniently measured in pico-seconds. The measurements were used at first to discuss the physiology of gas transport and to describe co-operativity in haemoglobin. More recently, the process of ligand binding has been dissected into intramolecular and intermolecular components. Relating the various rates to the abundance of structural information on crystals is so difficult that the work has barely begun, but the combination of kinetic measurements with genetic engineering and crystallography has promise, as well as problems, for the future.

Animals↗

PubMed2001

Collaboration and partnerships: developing the evidence base.

Despite the growing literature that collaboration is a 'good' thing, there are calls emphasising the need for evidence of its effectiveness. However, the nature of the evidence to assess effectiveness is less clear. This paper examines the components that contribute to the challenges that confront evidence on collaboration. It considers the differing interpretations that have been placed on evaluation and explores how ways of determining the outcomes of collaboration and the levels of outcome measurement to assess collaborative effectiveness are influenced by the multifactorial nature of the concept. Evidence on the impact of collaboration is influenced by the diversity of perspectives and conceptual facets, and difficulty in measurement of the notions involved. Other factors discussed are the choice of macro or micro evaluation, of proximal or distal indicators, of short and long-term effects, or of individual-level or collective community-level outcomes. The suitability of randomised controlled trials for the measurement of collaborative outcomes as well as the requirement of mixed methods evaluations are highlighted. An evaluation of five community partnerships in South Africa is employed as an example to link the evaluation concepts that are discussed to a real enquiry. If collaboration is to be successful in making a difference in the lives of people, then increasing the precision and context of appraising its effectiveness will reduce the nature of inconclusive evidence and is likely to improve the practice of partnerships, coalitions and joint working in health and social care.

Community Health Services↗

PubMed2003

Different meanings of quality of life: a comparison between what elderly persons and geriatric staff believe is of importance.

The principle aim of this study was to obtain a more complete understanding of quality of life (QoL) through exploring different factors affecting that concept among elderly persons and staff members, combining mixed methods for validation of QoL categories and themes, and enlightening the meanings through some quotes. Elderly persons (n = 207) as well as members of geriatric staff (n = 48) answered the open-ended question 'what does quality of life mean to you?'. The elderly persons also answered questions on health, loneliness and social contacts. Descriptive statistics, Spearman rank correlation coefficient, content analysis and triangulation were used to evaluate the data. The findings revealed differences in the answers regarding what was considered most important for QoL. Staff members overestimated two of the categories, namely health and social network, while the elderly persons themselves emphasised being appreciated and living a good life. Staff members believed that elderly persons want to be seen, listened to and feel useful. The only category where staff members and elderly persons differed was 'how to be treated', where the elderly group did not find it as important as the staff members. Furthermore, elderly persons did not wish to be a burden to their family or society. In conclusion, elderly persons's own viewpoint is highly significant in care planning.

Adult↗

PubMed1997

Undergraduate nursing students' perceptions of their clinical learning environment.

The clinical learning environment (CLE) is an interactive network of forces influencing student learning outcomes in the clinical setting. This study used mixed methods to identify factors characterizing students' perceptions of the CLE. The sample consisted of 229 undergraduate students in the second or third year of their biophysical nursing strand. The five subscales of the Clinical Learning Environment Scale, 'staff-student relationships', 'nurse manager commitment', 'patient relationships', 'student satisfaction' and 'hierarchy and ritual', were supported by qualitative data obtained from student interviews. Interpersonal relationships between the participants in the CLE were crucial to the development of a positive learning environment. Student satisfaction with the CLE was both a result of, and influential in creating, a positive learning environment. Nurse educators, clinical venues, and all others participating in the undergraduate nursing students' clinical education, must collaborate in order to create a CLE which promotes the development of well-educated registered nurses capable of providing safe, cost-effective patient care.

Adult↗

PubMed1999

Burnout and AIDS care-related factors in HIV community clinical nurse specialists in the North of England.

Burnout in Acquired Immune Deficiency Syndrome (AIDS) care nursing is well described in the literature from a hospital based perspective. No studies into the effects of AIDS care and burnout have been carried out within the community setting. A two-stage, mixed method study was carried out. In Stage one 30 Clinical Nurse Specialists in human immunodeficiency virus (HIV)/AIDS from the North of England completed the Maslach Burnout Inventory (MBI) and the AIDS Impact Scale. For Stage two five practitioners were selected randomly for semi-structured interview. Burnout morbidity was significant. Sixty-six per cent of informants scored as moderate or high burnout cases on the emotional Exhaustion and Personal Accomplishment subscales of the MBI. Only three per cent scored as cases on the depersonalization subscale. Links between the close involvement of practitioners with clients, death of clients, isolation, stigma and discrimination and the availability of support and supervision were identified as significant factors in AIDS care within this population that contributed to stress and burnout. Paradoxically, informants found the close relationships with clients, the autonomy of isolation and the exclusive nature of AIDS care positive aspects of their practice. The role of support and supervision in facilitating the continuance of a close empathic and therapeutic relationship and the prevention of an over-involved, isolated and stressful relationship is proposed as a way forward.

Acquired Immunodeficiency Syndrome↗

PubMed2001

The accessibility of research-based knowledge for nurses in United Kingdom acute care settings.

BACKGROUND: The successful dissemination of the results of the National Health Service (NHS) research and development strategy and the development of evidence based approaches to health care rely on clinicians having access to the best available evidence; evidence fit for the purpose of reducing the uncertainties associated with clinical decisions. AIM: To reveal the accessibility of those sources of information actually used by nurses, as well as those which they say they use. DESIGN: Mixed method case site, using interview, observational, Q sort and documentary audit data in medical, surgical and coronary care units (CCUs) in three acute hospitals. RESULTS: Three perspectives on accessibility were identified: (a) the humanist--in which human sources of information were the most accessible; (b) local information for local needs--in which locally produced resources were seen as the most accessible and (c) moving towards technology--in which information technology begins to be seen as accessible. Nurses' experience in a clinical specialty is positively associated with a perception that human sources such as clinical nurse specialists, link nurses, doctors and experienced clinical colleagues are more accessible than text based sources. Clinical specialization is associated with different approaches to accessing research knowledge. Coronary care unit nurses were more likely to perceive local guidelines, protocols and on-line databases as more accessible than their counterparts in general medical and surgical wards. Only a third of text-based resources available to nurses on the wards had any explicit research base. These, and the remainder were out of date (mean age of textbooks 11 years), and authorship hard to ascertain. CONCLUSION: A strategy to increase the use of research evidence by nurses should harness the influence of clinical nurse specialists, link nurses and those engaged in practice development. These roles could act as 'conduits' through which research-based messages for practice, and information for clinical decision making, could flow. This role should be explored and enhanced.

Acute Disease↗

PubMed2002

An evaluation of the role of the Clinical Placement Coordinator in student nurse support in the clinical area.

PURPOSE OF THE STUDY: The purpose of this study was to evaluate the role of the Clinical Placement Coordinator (CPC) and the continued development of the role in the context of the provision of student support in the clinical area. BACKGROUND: Following the introduction of the Registration/Diploma in Nursing Studies programme in the Republic of Ireland in 1994 the post of CPC was created to support student nurses in the clinical area. The CPC is an experienced nurse who provides dedicated support to student nurses in a variety of clinical settings however, unlike the role of mentor/preceptor they do not have a client/patient caseload. To date no major evaluation of the post has taken place. Therefore the Department of Health and Children commissioned a national evaluation of the post of which part of the findings are reported in this paper. METHODOLOGY: A two-stage study is described utilizing a mixed-methods approach. Data collection included individual and focus group interviews and questionnaires. Interviews were analysed using thematic content analysis and data collected from questionnaires were analysed utilizing descriptive and inferential statistics. FINDINGS: An analysis of the data identified the responsibilities and functions of CPC were multivariate, however, core elements of the role were evident. The core elements were identified as student support and practice development. The central and most frequent finding from the data collected was the individual support students received from CPCs throughout their clinical placement. CONCLUSION: The role of CPC was evaluated as a positive addition to the realm of student support and the clinical team. The positioning of the post in the clinical area also adds the dimension of a CPC being a link between student nurses and the various groups that provide student support, this is essential in light of the changing role of the nurse tutor following the full integration of preregistration nurse education into the third-level sector and the development of a formal preceptorship role for clinical nurses in the Republic of Ireland.

Attitude of Health Personnel↗

PubMed2002

Power and control: forensic community mental health nurses' perceptions of team-working, legal sanction and compliance.

This is the second of two papers reporting on a descriptive mixed methods study of community forensic mental health nurses' experiences of restriction orders and supervised discharge mechanisms. Forensic community mental health nurses (FCMHNs) have a body of experience of working with mentally disordered offenders in the community. A number of these patients will be subject to conditions on discharge. This in effect acts as compulsory community treatment with the sanction of recall to hospital. This paper examines nurses' perceptions of team-working, legal powers and their effects upon compliance. Findings include that FCMHNs express general satisfaction with their input to decision-making but some concerns were raised that challenge the ethic of team-working. Respondents were broadly in favour of increased professional responsibility, although this may be related to a quest for status. A pragmatic if equivocal support for the use of compulsion in community mental healthcare was also expressed.

Anecdotes as Topic↗

PubMed1998

Kinetics and specificity of reductive acylation of wild-type and mutated lipoyl domains of 2-oxo-acid dehydrogenase complexes from Azotobacter vinelandii.

The kinetics and specificity of reductive acylation of lipoyl domains derived from Azotobacter vinelandii 2-oxo-acid dehydrogenase complexes, catalysed by A. vinelandii and Escherichia coli complexes, have been investigated. With the wild-type pyruvate dehydrogenase complex from A. vinelandii the rate of reductive acetylation and deacetylation was studied by rapid mixing methods. The rate of reductive acetylation, 126 s(-1), corresponds well with the turnover rate derived from steady-state measurements. Deacetylation was rapid and specific for coenzyme A. No deacetylation was observed with reduced or oxidised lipoamide or with dithiothreitol. The rate of reductive acetylation of complex-bound lipoyl domains by pyruvate dehydrogenase (E1p) is at least 60 times higher than of free lipoyl domains under comparable conditions. This gain in catalytic rate indicates a large diffusion limitation of lipoyl domains when attached via the flexible linker segments to the complex, and illustrates the efficiency of substrate channeling in the multienzyme complex. The 2-oxo-acid dehydrogenases exhibit specificity for lipoyl domains in the reductive acylation reaction. The A. vinelandii lipoyl domain derived from the pyruvate dehydrogenase complex is a good substrate for A. vinelandii E1p, but not for A. vinelandii 2-oxoglutarate dehydrogenase (E1o), and vice versa. The A. vinelandii lipoyl domain of the pyruvate dehydrogenase complex is also, although at a lower rate, reductively acetylated by E. coli E1p and reductively succinylated by E. coli E1o. Likewise, the A. vinelandii lipoyl domain derived from the 2-oxoglutarate dehydrogenase complex is recognised by E. coli E1o, but not by E. coli E1p. This suggests that common determinants of the lipoyl domains exist that are responsible for recognition by the E1 components. On the basis of the observed specificity and lipoyl domain sequences and structures, an exposed loop of the A. vinelandii 2-oxoglutarate dehydrogenase complex lipoyl domain was subjected to mutagenesis. Although the reductive acylation experiments of mutants of the lipoyl domain indicate the importance of this loop for recognition, it is probably not the single determinant for specificity.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗