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PubMedDate not supplied

Getting back to the future: a grounded theory study of the patient perspective of total knee joint arthroplasty.

PURPOSE: The purpose of this study was to describe the experience of adults with osteoarthritis who had undergone a total knee joint arthroplasty. METHOD: Grounded theory qualitative methodology was applied. SAMPLE: Purposive and theoretical sample of nine participants. FINDINGS: In managing the experience of total knee joint arthroplasty, participants expressed the basic psychosocial process, "Getting back to the future." There were three main categories identified within this process, "enduring," "thinking twice," and "keeping faith." "Enduring" conceptualized the way the participants lived their daily lives. "Thinking twice" captured the participants' processes of adaptation and problem solving. "Keeping faith" was the combination of determination, trust, and optimism that sustained participants as they progressed through the total knee joint arthroplasty experience to rehabilitation. CONCLUSION: The study provides a grounded theory of the participants' perspectives of undergoing total knee joint arthroplasty, making the process more visible for those involved in their care. Prehabilitation, postoperative care, and discharge planning can facilitate the patients' optimism and motivation to self-help. Further research to explore the process from the perspective of patients with rheumatoid arthritis and patients who have complications is recommended.

Activities of Daily Living↗
PubMed2001

Modeling solute diffusion in the presence of pore-scale heterogeneity: method development and an application to the Culebra dolomite member of the Rustler Formation, New Mexico, USA.

Previous studies have revealed the presence of pore-scale variability in diffusivity in the Culebra (dolomite) member of the Rustler Formation, NM. In this study, eight laboratory-scale diffusion experiments on five Culebra samples were analyzed using a methodology for modeling solute diffusion through porous media in the presence of multiple matrix diffusivities, Dp. A lognormal distribution of Dp is assumed within each of the lab samples. The estimated standard deviation (sigma d) of ln(Dp) within each sample ranges from 0 to 1, with most values lying between 0.5 and 1. The variability over all samples leads to a combined sigma d in the range of 1.0-1.2, which is consistent with the distribution of independently determined formation factor measurements for similar Culebra samples. A comparison of our estimation results to other rock properties suggests that, at the lab-scale, the geometric mean of Dp increases with bulk porosity and the quantity of macroscopic features such as vugs and fractures. However, sigma d appears to be determined by variability within such macroscopic features and/or by micropore-scale heterogeneity. In addition, comparison of these experiments to those at larger spatial scales suggests that increasing sample volume results in an increase in sigma d.

Calcium Carbonate↗
PubMed1995

The Descriptor Differential Scale of Pain Intensity: an evaluation of item and scale properties.

Improved methods for pain measurement have both theoretical and clinical importance. This study evaluated the Descriptor Differential Scale (DDS) of Pain Intensity, a recent methodology designed for assessing pain reports in clinical samples. Experiment 1 evaluated the sensitivity of the measure to small changes in electrocutaneous stimulation relative to a traditional visual analogue scale (VAS) of pain intensity. Additionally, direct psychophysical scaling methods were employed to determine ratio-scale values for the DDS sensory items in relation to the electrocutaneous stimuli. This ratio scale was cross-validated by comparison with previously published ratio-scaled data from cross-modality matching pain intensity judgement studies. Experiment 2 evaluated the performance of the measure in both experimental and clinical pain samples, as well as the similarity of item-response patterns in each of these samples. Results indicate that the DDS of Pain Intensity is sensitive to small changes in electrocutaneous stimulation, has consistent ratio-scale properties across two different psychophysical methods, and demonstrates similar item-response patterns across divergent experimental and clinical samples. The results support the validity of the sensory DDS as a measure of pain intensity.

Adult↗
PubMed2003

Influence of extender, temperature, and addition of glycerol on post-thaw sperm parameters in ram semen.

Using a two-step extension methodology, two experiments were conducted using a split-sample design to compare the effect on post-thaw ram sperm parameters of a milk-based extender (Experiment 1) containing four different egg yolk concentrations (5% [M5], 10% [M10], 15% [M15], and 20% [M20]), and a commercially available extender (Bioexcell); IMV, L'Aigle, France) free from additives of animal origin, containing two different final glycerol concentrations (3.2% [B] and 6.4% [BB]) (Experiment 2). In both experiments, glycerol was added either at 5 degrees C or at 15 degrees C together with the second fraction of each extender. The sperm characteristics assessed were motility (measured subjectively [SM] and by means of cell motion analysis (CASA), membrane integrity (SYBR-14/PI), and capacitation status (chlortetracycline (CTC)/EthD-1). Results of Experiment 1 showed no significant positive effect of increasing the concentration of egg yolk above 10% on post-thaw motility, membrane integrity, or induction of sperm capacitation-like changes. In Experiment 2, Bioexcell (BB) yielded similar post-thaw results as did the milk extender (control). In both experiments, post-thaw sperm parameters were better preserved when glycerol was added at 5 degrees C, although the results were not always statistically significant for all variables studied. In conclusion, when using milk-based extenders for freezing ram semen, low (5-10%) concentrations of egg yolk and the addition of glycerol at 5 degrees C are recommended. Furthermore, the results indicate that when freezing ram semen, Bioexcell containing 6.4% glycerol may be used as an alternative extender to the conventional milk extender containing 5% egg yolk.

Acrosome Reaction↗
PubMed2004

Serotonergic platelet markers of suicidal behavior--do they really exist?

BACKGROUND: Abnormal changes in platelets used as peripheral markers of central serotonergic functions are said to be associated with suicidality and depression, but this association has not been supported by consistent findings. AIM: This review based on selected, often quoted publications in this area focuses firstly, on obviously contradictory findings and, secondly, on potential methodological flaws explaining these discrepancies. RESULTS: The platelet 5-HT transporter has been found to have an inconsistent association with suicidality; furthermore, the specificity of imipramine for the 5-HT transporter is most likely low, since the number of platelet impramine binding sites has not been reliably associated with platelet serotonin uptake (Vmax). Significant changes of platelet serotonin content in suicidal individuals, as described in various studies, are most likely due to washout periods that are too short to eliminate the effects of a previous drug intake, or, in violent suicide attempters, due to blood loss and dilution. Similar methodological shortcomings might account for an often-reported elevated number of platelet 5-HT(2) receptor binding sites in suicidal individuals. In many studies, the results have not been sufficiently controlled for drug effects on platelet 5-HT(2) receptors, and associations of platelet 5-HT(2) binding with selective classifications of suicidal behavior are often generalized as further evidence for an association of platelet 5-HT(2) receptors with 'suicidality'. Finally, changes in platelet MAO-B-activity in suicidal patients have not been reproducibly found, and the impact of smoking on MAO-B activity has not been controlled in any studies. CONCLUSIONS: Methodological flaws such as small sample sizes, insufficient matching criteria for controls, use of inadequate ligands in binding experiments, nonconsideration of comorbidity etc. and considerable methodological differences between studies limit their validity and comparability. It does not seem possible, at present, to integrate published findings and concepts into a plausible biological model of suicidality.

Biomarkers↗
PubMed1983

Physical chemistry of freeze-drying: measurement of sublimation rates for frozen aqueous solutions by a microbalance technique.

The sublimation rate of frozen solutions was studied as a function of freezing rate, thickness of dried product (l), temperature, residual air pressure, and solute concentration. Data are presented for pure water, aqueous potassium chloride, aqueous povidone, and aqueous dobutamine hydrochloride-mannitol (System I). The resistance of the dried product to water vapor flow (Rp) was evaluated from the sublimation rate and the sample temperature. The primary experimental technique was based on freeze-drying a cylindrical microsample isothermally, with the sample suspended from one arm of a vacuum microbalance. Methodology to evaluate resistance data from vial freeze-drying experiments is also described. In separate experiments, samples in the form of a thin (15-microns) film were visually observed through a microscope during freeze-drying. Freeze-drying of most samples appeared to occur by water vapor escaping through open channels created by prior sublimation of ice. Contrary to the usual theoretical model, Rp is neither independent of temperature nor directly proportional to l. Rather, Rp decreases with increasing temperature and the l dependence is normally of the form Rp = (A0 + A1l)/(1 + A2l), where Ai (i = 0, 1, 2) are constants. In several cases, Rp is very large near l = 0, decreases sharply at l congruent to 0.1 cm, and obeys the above equation where l greater than 0.2 cm, a result suggesting an amorphous surface skin which cracks on desorption of water. The temperature dependence of Rp suggests that, as the sample temperature approaches the eutectic (or collapse) temperature, hydrodynamic surface flow of adsorbed water is an important flow mechanism.

Air Pressure↗
PubMed2003

Extent of linkage disequilibrium in a Sardinian sub-isolate: sampling and methodological considerations.

The extent of linkage disequilibrium (LD) is an important factor when designing experiments for mapping disease or trait loci using LD mapping methods. It depends on the population history and hence is a characteristic of each population. Here, we have assessed the extent of LD in a sub-isolate of the general Sardinian population (775 members of one village) using 22 polymorphic markers on chromosome 19. We found high levels of disequilibrium that extended to 8 cM, when based on D', and 11 cM when based on the significance level of the allelic association. The fact that conclusions based on both methods are similar suggests that the estimates are quite robust. We have also shown, through a simple resampling technique, that small sample sizes can overestimate both the mean value of D' and its variance up to a factor of about 2 and 16, respectively, when the number of diplotypes (the pair of haplotypes that compose the genotype) decreased from 186 to 26. We evaluated the effect on D' of the depth of the pedigree available when using phased founders, and compared the estimates with those obtained when using unphased founders, and also the effect of grouping alleles on the value of D' and the significance level. Owing to the high sampling variance of LD, we recommend the use of at least 200 unrelated individuals when characterizing the extent of LD.

Alleles↗
PubMed1999

Group sequential procedures for repeated events data with frailty.

In this article we consider the design aspects of group sequential trials with recurrent study endpoints, where the subjects are from a heterogeneous population. The usual procedures of sequential analysis based on the "independent increments" property are no longer valid due to the heterogeneity of the study subjects, as pointed out by Cook and Lawless. We focus on the aspect of study planning and consider a special model (Poisson process with frailty) to investigate the effects of frailty (or subject heterogeneity). We prescribe the valid procedures and provide convenient tables for computing stopping boundaries and sample sizes. The methodology is illustrated through an example of an animal experiment with recurrent tumors, using procedures such as group sequential tests and repeated confidence intervals. Minimal cost analysis is considered for determining the optimal combination of study duration and sample size.

Animals↗
PubMed2000

Substance abuse and childhood maltreatment. Conceptualizing the recovery process.

Research exploring the dual, yet related, issues of adulthood substance abuse and childhood maltreatment remains limited to the effects of such experiences on the individual. To date, clinical literature has failed to explore the ways in which individuals, particularly women, cope with and recover from these experiences. The current study applied a qualitative methodology to a sample of six women. Respondents had completed a minimum of 3 years of chemical-free living and self-identified as survivors of prolonged childhood sexual abuse. Women participated in a semi-structured interview to detail their recovery process. Results show support for a multifactorial process of recovery; specifically, strategies aimed at affect regulation, development of a new self-concept, and the forging of more adaptive attachment styles. The implications of these results are discussed in the context of improving clinical intervention strategies and encouraging additional research endeavors to understand this complex process.

Adult↗
PubMed2004

The race gap in support group participation by breast cancer survivors: real or artifact?

Addressing methodological weaknesses of previous research, this study assesses whether African American women are, in fact, less likely to participate in breast cancer support groups than are White women. Of the breast cancer survivors, 958 (26% African Americans, 73% Caucasian) completed interviews concerning demographic characteristics, other support networks, effects of illness on home and spiritual life, and support group participation. Contrary to previous research, no race difference was found in support group participation. This research suggests more effort needs to be paid to sampling techniques and other methodological factors to adequately reflect the experiences and needs of breast cancer survivors, specifically African American women.

Black People↗
PubMed2004

Expression of serotonin receptor mRNAs in human ciliary body: a polymerase chain reaction study.

BACKGROUND: Previous research has indicated a role for serotonin (5-HT) in the anterior uvea of the eye. The purpose of this study was to examine whether mRNAs encoding particular 5-HT receptors are expressed in the ciliary body and iris of a number of human subjects. METHODS: The presence of mRNA encoding 5-HT receptors in four human ciliary body samples was determined by reverse transcription-polymerase chain reaction experiments using a standard methodology. RESULTS: Positive signals for 5-HT(1A), 5-HT(2A), 5-HT(2B), 5-HT(2C) and 5-HT(7) receptor mRNAs were detected in the samples prepared from various human ciliary body samples. CONCLUSION: The detection of certain 5-HT receptor mRNAs in the human ciliary body supports the hypothesis that serotonin is involved in the control of aqueous dynamics and indicates that ligands acting on these 5-HT receptors may have potential use as intraocular pressure-lowering agents.

Ciliary Body↗
PubMed1998

Simultaneous Determination of Two-Phase Relative Permeability and Capillary Pressure of Porous Rocks from Steady-State Flow Experiments: Accounting for Gravitational Forces and Fluid Compressibility.

A methodology for simultaneously measuring two-phase relative permeability and capillary pressure of porous rock samples from steady-state flow experiments, reported by Virnovsky et al. in 1995, is considered. The method requires measuring pressure drops in individual fluid phases across a rock sample. This paper studies the role of gravitational forces, neglected in the original derivation of the method. Direct numerical simulations of steady-state vertical flow experiments, performed over a typical range of rocks and flow parameters, show that the error caused by neglecting gravitational forces in the original method, is acceptable even for extremely high ( approximately 10(-10) m2) permeability samples. Thus, if multiphase flow measurements are performed on vertical samples, the gravitational force can be neglected for estimating relative permeability and capillary pressure. An extension of this method to the case of compressible fluids is presented. Copyright 1998 Academic Press.

Journal Article↗
PubMed1997

High-fidelity PCR amplification of infectious copies of the complete simian virus 40 genome from plasmids and virus-infected cell lysates.

We describe here a long-polymerase chain reaction (PCR) method that can be used to amplify complete simian virus 40 (SV40) DNA with high fidelity, and we show that authentic, viable virus can be produced from molecular clones of the PCR-amplified viral DNAs. A commercial long-PCR kit that employed a combination of Taq and GB-D polymerases was used, together with a pair of overlapping primers that recognized a unique EcoRI site in the SV40 genome. Efficient amplification required linearization of the circular SV40 genomic DNAs with EcoRI. Entire SV40 genomes were successfully PCR-amplified from an SV40 plasmid and from two different SV40-infected cell lysates and were cloned into pUC-19. Three separate segments of the cloned viral genomes were DNA sequenced, and no nucleotide changes relative to the parental virus were detected, suggesting that the viral DNAs had been amplified with high fidelity. Each PCR clone was infectious, and no differences were detected in the growth characteristics of viruses derived from these clones as compared to the original viral strain. The procedure we utilized shortens and simplifies the molecular cloning of small double-stranded DNA viruses and will be useful for viral diagnostic tests and for recovery of virus from clinical samples. The results of these experiments have broad implications, as the methodology is applicable to many systems.

Base Sequence↗
PubMed1998

Childhood maltreatment and the risk of substance problems in later life.

This paper examines the risk of developing problems in adolescence and adulthood, particularly those associated with substance use, as a consequence of experiencing physical or sexual abuse during childhood. We review both retrospective and prospective research, conducted with both adolescent and adult respondents. Although there are some marked discrepancies in the findings from retrospective and prospective studies, these are probably due to differences in methodology, particularly between using official records and self-report to identify cases of abuse. Despite the wide range of methodologies and samples used in these studies, most indicate that the experience of childhood abuse is a risk factor for a number of common mental disorders in adolescence and adulthood, including alcohol and drug-related problems. In many cases, the experience of abuse appears to lead in later life to increased feelings of depression and anxiety which, while not sufficient to result in the diagnosis of a mental health disorder, place the victims at greater risk of developing substance problems. Multivariate studies indicate that this positive association remains even when controlling for important variables such as the presence of parental alcohol problems. The paper concludes with a number of recommendations for future research, so that it can be established whether the risk arises specifically from child abuse or neglect, or from the more general impact on child development of adverse family relationships.

Journal Article↗
PubMedDate not supplied

Estimation of porous media flow functions using NMR imaging data.

Nuclear magnetic resonance (NMR) imaging data measured during two-phase displacement experiments on porous rock core samples are used in an inverse problem methodology to estimate the two-phase flow functions relative permeability and capillary pressure. Nuclear magnetic resonance imaging data contain valuable information about variation of fluid states within the core sample and are therefore important for accurate estimation of these properties. A precise agreement between measured data, which also includes pressure drop across the core samples, and the data simulated by using the estimated flow functions is found, indicating accurate flow function estimates.

Alkanes↗
PubMed2001

Reflection as a transforming process: student advanced nurse practitioners' experiences of developing reflective skills as part of an MSc programme.

AIM OF THE STUDY: The aim of this study was to explore student advanced nurse practitioners' (ANPs) experiences of reflection. BACKGROUND: The implementation of a National Health Service (NHS) Executive initiative to develop a Master's Course in advanced nursing practice at Wolverhampton University provided the background to the study. The course was designed to enable experienced nurses to take on activities previously considered the province of physicians. The aim was to extend practice within a holistic nursing framework. Reflection was perceived as central to this process. A pre-entry degree level reflective practice module and a reflective component for the level 4 (Master's level) Practice Module were devised to enhance practitioners' reflective skills. RATIONALE: The rationale for the study was that it should explore student ANPs' perceptions of reflection following completion of these modules, to evaluate their experiences and inform curriculum development. DESIGN/METHODS: A qualitative methodology was used. The sample comprised 14 ANP students. Interviews and reflective learning contracts were used to collect the data. Colaizzi's (1978) seven-stage model guided data analysis. FINDINGS: The findings indicated that all but one of the students described the development of their reflective skills positively. Changes are described in students' thinking and behaviour. CONCLUSIONS: The conclusions have implications for ANPs, for patient care, and for others seeking to develop the ANP role.

Attitude of Health Personnel↗
PubMedDate not supplied

The peritoneal dialysis experience: insights from long-term patients.

This exploratory-descriptive study identifies dimensions of self-management demonstrated by patients with end stage renal disease (ESRD) who have been successfully treated with peritoneal dialysis (PD) for more than 4 years (range = 4.1 to 13.1 years, mean = 7.5 years). After IRB review, semi-structured interviews were conducted with 18 individuals, 10 male and 8 female; 11 Caucasian, 6 African-American, and 1 Hispanic. Respondents ranged in age from 33 to 86 years (mean = 54.4 years). Interviews were audio-recorded and verbatim transcriptions were analyzed according to a content analytic procedure, with movement from specific to general. Two broad domains of self-management were identified: autonomy/control in health care and normality in everyday life. Autonomy/control was comprised of three specific dimensions: partnership in care, self-care, and self-care self-efficacy. Normality in everyday life included the dimensions of flexibility/freedom, interpretation of illness severity, and perception of body image. Although the small sample size and methodology limit generalizability, insights into the lived self-management experience on PD were identified. Such insights lay the groundwork for development of interventions to facilitate informed decision-making regarding dialysis modality, to teach tactics for effective self-management on PD, and to help health care professionals to support the self-management efforts of patients on PD.

Adaptation, Psychological↗
PubMed1998

Sun protection behaviours and the predictors of sunburn in young children.

OBJECTIVE: To explore the use of sun protection behaviours and the experience of sunburn in a sample of parents and their children in New Zealand. METHODOLOGY: Information was collected from 887 parents using postal questionnaires at the beginning of and during the summer. RESULTS: Thirty per cent of the parents believed their child looked healthier with a suntan, and 40% intended to let their child get a suntan during the summer. Predictors of intention to tan included level of parental education, the child's age, the child's sensitivity to burning and experience of sunburn in the parent. At the end of the summer period, 29% of the children were reported as being sunburned. Predictors of sunburn in the child were the age of the child, experience of sunburn in the parent and use of sunscreen SPF15+ by the parent. CONCLUSION: Despite intense media coverage of the dangers of overexposure to the sun, it is clear that a significant proportion of children are still getting sunburned.

Adult↗