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PubMedDate not supplied

[Identification of the actual experiencing of pain. Methodological basis for an evaluation].

FUNDAMENTALS: The doctors don't have reliable instruments in order to detect the painful experience in a patient with intention of deceiving. The objective of this investigation is the development of an instrument that helps the doctors on that task. METHOD: The investigation is based on that the pain is not possible to evoke. A patient that doesn't feel pain, really, will introduce the modifications characteristic of all memory when requests you that he/she describe the pain that says feel. The will of deceit will also distort their description. A discriminant analysis will detect the difference between the description of a pain that is not present and another that yes it are, and between the sincere descriptions of the deceiving one. RESULTS: The descriptions of the pain carried out by two different samples of nursing students have been studied with a list of pair of antonym adjectives (Osgood's semantic differential). A subgroup of the first sample described a pain that they suffered in the same moment of description, and the other subgroup described a suffering pain some days before. In the other sample, a subgroup made a sincere description of their pain and other subgroup described the pain with will of deceiving the interviewer. The investigation has provided two discriminant models. A discriminant model differentiates between a present and another remembered pain (sensibility: 0.75; specificity: 0.85; kappa reliability: 0.60; p < 0.000000001; probability of success p: 89%). The other discriminant model differentiates between a description of a pain with will of deceiving and another pain described sincerely (sensibility: 0.94; specificity: 0.95; kappa reliability: 0.89; p < 0.000000001; probability of success p: 97%). CONCLUSIONS: The results of this investigation seem to demonstrate that it is possible to discriminate between the descriptions of real pains and the suspicious pains of not being real, and that also one is able to discriminate between pains described with will of deceit and pains described sincerely. These discriminant models allows to classify the description of the subjects in four groups: "liars", "sincere", "magnifiers", and "psychogenic". However, it is necessary still carry out more effort of investigation so that these results could be replied in patients that suffer pain.

Adult↗

PubMed1991

Selenium bioavailability as selenite (74Se) and as a selenium drug (76Se) by stable isotope methodology.

Many forms of selenium supplement are commercialized. The purpose of this work was to study the bioavailability of one selenium drug, "Granions de Sélénium", as compared with sodium selenite. Each product was labelled with enriched stable isotopes, and by means of gas chromatography/mass spectrometry (GC/MS), the metabolism of the two forms was followed simultaneously. In a first study, the absorption of a single dose of 480 micrograms Se (Na-Selenite) containing 100 micrograms of 74Se was compared with that of 480 micrograms Se (Granions) containing 100 micrograms of 76Se. Measurement precision was mediocre and only apparent absorption, urinary excretion and body retention could be measured. In a second experiment, kinetic studies were performed after a single oral dose of 100 micrograms of 74Se (Na-selenite) and 100 micrograms of 76Se (Granions). Blood, urine and feces samples were collected for a week to determine the true absorption, plasma half-life, and turnover of these two compounds. No significant difference in the metabolism of selenium was observed between "Granions de Sélénium" and selenite. Both present two maximal absorption peaks at 6 h and 12 h and a bioavailability of 76%.

Adult↗

PubMed2004

A method for measuring the size distribution of latex particles by scanning force microscopy.

A methodology has been developed to accurately determine the size distribution of latex particles using the scanning force microscope (SFM). Unlike other workers, who have generally measured the lateral dimensions of monolayers of latex particles using a global quantification method, we have measured the heights of individual latex particles located at the edges of latex monolayers that were immobilised onto mica substrates. In agreement with other work, we noted that the edges of monolayers of latex particles provided stable and reproducible scanning force imaging. Whilst SFM imaging noise, image processing artifacts, tip/sample forces and variations in the mica substrate are sources of measurement error that should not be overlooked, our experience has been that the variation over time of the sensitivity of the Z actuator is the greatest potential uncertainty in determining the heights of latex particles. The methodology that we used requires frequent calibration of the Z actuator of the SFM, typically before and after two or three images, in order to ensure that the uncertainties in the Z sensitivity are known and minimised. This methodology was developed for an SFM instrument that was equipped with open loop piezoelectric actuators following a careful study of the behaviour of those actuators. Using this methodology, we have measured the size distributions of populations of 300-400 latex particles from each of several different latex samples, with the maximum variation in the Z-actuator calibration experienced during the measurement of a sample being less than 2%, often about 1% and occasionally better still. In so doing, we have demonstrated that SFMs equipped with open loop actuators can be used for high confidence quantitative measurements of step heights.

Journal Article↗

PubMed2001

Inverse 18O labeling mass spectrometry for the rapid identification of marker/target proteins.

Systematic analysis of proteins is essential in understanding human diseases and their clinical treatments. To achieve the rapid and unambiguous identification of marker or target proteins, a new procedure termed "inverse labeling" is proposed. With this procedure, to evaluate protein expression of a diseased or a drug-treated sample in comparison with a control sample, two converse labeling experiments are performed in parallel. The perturbed sample (by disease or by drug treatment) is labeled in one experiment, whereas the control is labeled in the second experiment. When mixed and analyzed with its unlabeled counterpart for differential comparison using mass spectrometry, a characteristic inverse labeling pattern of mass shift will be observed between the two parallel analyses for proteins that are differentially expressed. In this study, protein labeling is achieved through 18O incorporation into peptides by proteolysis performed in [18O]water. Once the peptides are identified with the characteristic inverse labeling pattern of 18O/16O ion intensity shift, MS data of peptide fingerprints or peptide sequence information can be used to search a protein database for protein identification. The methodology has been applied successfully to two model systems in this study. It permits quick focus on the signals of differentially expressed proteins. It eliminates the detection ambiguities caused by the dynamic range of detection on proteins of extreme changes in expression. It enables the detection of protein modifications responding to perturbation. This strategy can also be extended to other protein-labeling methods, such as chemical or metabolic labeling, to realize the same benefits.

Biomarkers↗

PubMed2001

Role of nonesterified fatty acids in necrotizing pancreatitis: an in vivo experimental study in rats.

INTRODUCTION: In acute pancreatitis, nonesterified fatty acids (NEFA) might be released by lipase and cause tissue necrosis by their detergent properties, but this has not been established in vivo. AIMS: To measure the release of NEFA in the blood stream, pancreatic tissue, and peritoneal cavity during taurocholate-induced acute necrotizing pancreatitis in rats. METHODOLOGY: Ascites and blood were repeatedly sampled; after 24 hours, pancreatic lesions were scored, and NEFA were measured in the pancreas. The effects of a specific lipase inhibitor (Tetrahydrolipstatin [THL]) were also studied. RESULTS: A slight transient increase (22%) of NEFA concentration was observed in systemic circulation but did not parallel the time course of lipase activity, arguing against an intravascular production of NEFA by circulating lipase. Pancreatic NEFA did not differ between rats with pancreatitis and control rats. NEFA in ascites increased to threefold the basal value immediately after taurocholate and decreased rapidly thereafter, whereas lipase increased later in ascites and remained elevated during the 24-hour duration of the experiment. Lipase inhibition by THL neither modified the early increase of NEFA in ascites, nor altered the macroscopic, enzymatic, and histologic evolution of pancreatitis. CONCLUSION: This in vivo study does not confirm the hypothetical role of NEFA produced by pancreatic lipase in the necrotic process and its systemic complications, up to now mainly suggested on the basis of ex vivo experiments.

Animals↗

PubMed1995

User satisfaction with in-patient mental health services.

Although a wealth of literature regarding lay evaluation or satisfaction with health services exists, a paucity of literature is available about satisfaction with mental health services. Much of this literature is fraught with methodological problems. The study described, using both quantitative and qualitative methodology, investigated how users of in-patient mental health services evaluated these services with particular reference to the areas of the admission process, treatment, ward environment and safety. The findings confirmed the broad outcomes reported in the literature, in that they demonstrated the mismatch between quantitative and qualitative data. Global satisfaction ratings were generally positive; however, more specific questions yielded less positive outcomes. Semi-structured interviews reported some important areas of dissatisfaction, including a lack of information regarding treatment and services. Fears relating to safety were expressed equally by male and female users. Further work in this area is required with larger samples, and with specific reference to the experience of ethnic minorities and those detained under the Mental Health Act.

Female↗

PubMed1999

Defining the eligible, accessible population for a phenomenological study.

When a rare target population is the focus of a proposed descriptive, phenomenological study, it is important to project the size of the population that is both eligible to participate and accessible to the investigator. This estimate of the eligible, accessible population is one basis for judging the feasibility of a proposed phenomenological study, and it serves to establish a demographic framework for the analysis. While preparing a grant proposal for a phenomenological study of older widows' experience of home care, the author developed a method of estimating the eligible, accessible population. The philosophical rationale for the method is explained, and its procedures are detailed. Suggestions are given for adapting the method in keeping with the aims of a particular phenomenological study.

Aged↗

PubMed2005

Strategies in assessing post operative pain--a South African study.

The purpose of this validation study was to describe strategies used in postoperative pain assessment among a group of nurses in South Africa. A mixed qualitative and quantitative study was conducted in a 950-bed academic hospital complex. Surgical nurses (n = 12) carried out pain assessments of postoperative patients (n = 36) in pain. Data were collected using detailed interviews and pain intensity was estimated on a visual analogue scale (VAS, 0-10 cm). Nurses used four categories of criteria (a) how the patient looks, (b) what the patient says, (c) the patient's way of talking, and (d) experience of similar circumstances and drew on their past experiences in five different ways: (a) some patients report lower pain intensity than expected, (b) a typology of patients, (c) a focus on listening to patients, (d) what to look for, and (e) what to do for patients were identified. The system of categories described by Sjöström [Sjöström B. Assessing acute postoperative pain. Assessment strategies and quality of clinical experience and professional role. Göteborg: Acta Universitatis Gothoburgensis; 1995] was valid for this sample with an additional category. The different categories seem to be complementary and necessary for assessing pain in others. The findings have implications for professionals who provide care for patients in pain.

Adult↗

PubMed1975

[Effects of ethinyl estradiol compared with norethisterone (pure or contaminated) on vaginal keratinization of castrated rats].

Norethisterone samples are often contaminated by estrogen traces which can be measured by mass spectrometry and which invest the progestative with estrogenic properties in the Allen and Doisy test. Therefore, one had better, in pharmacodynamic experimenting, use samples that have been purified by chromatography or that are pure out of synthesis. However, one will not forget these are not without some estrogenicity, a fact which seems linked to the very nature of the norethisterone molecule.

Animals↗

PubMed1996

Biological monitoring of butadiene exposure by measurement of haemoglobin adducts.

The measurement of haemoglobin (Hb) adducts is an important tool for monitoring exposures to industrial chemicals such as ethylene, ethylene oxide and propylene oxide. The aim of the present study was to use this method to monitor occupational exposure to butadiene. The methodology was evaluated with Hb samples obtained by reacting butadiene monoepoxide (BMO), the primary reactive metabolite of 1,3-butadiene, with blood and by dosing BMO to rats and mice. The Hb adducts: N-(2-hydroxy-3-buten-1-yl)valine and N-(1-hydroxy-3-buten-2-yl)valine were determined as the pentaflurophenylthiohydantoin derivatives using the modified Edman degradation procedure and gas chromatography with negative ion chemical ionisation mass spectrometry. The adducts were quantified using d4-N-(2-hydroxyethyl)valine as an internal reference chemical. Relatively high background signals were observed which made accurate quantitation difficult. The lower limit of detection was estimated as 10-20 pmol/g globin. The experiments have demonstrated that appropriate reference samples are required for accurate quantitation and the method requires further refinement to improve the sensitivity of the analysis.

Animals↗

PubMed2006

A general numerical analysis of time-domain NQR experiments.

We introduce a general numerical approach for solving the Liouville equation of an isolated quadrupolar nuclide that can be used to analyze the unitary dynamics of time-domain NQR experiments. A numerical treatment is necessitated by the dimensionality of the Liouville space, which precludes analytical, closed form solutions for I > 3/2. Accurate simulations of experimental nutation curves, forbidden transition intensities, powder and single crystal spectra, and off-resonance irradiation dynamics can be computed with this method. We also examine the validity of perturbative approximations where the signal intensity of a transition is proportional to the transition moment between the eigenstates of the system, thus providing a simple basis for determining selection rules. Our method allows us to calculate spectra for all values of the asymmetry parameter, eta, and sample orientations relative to the coil axis. We conclude by demonstrating the methodology for calculating the response of the quadrupole system to amplitude- and frequency-modulated pulses.

Algorithms↗

PubMed1999

'Finding a good thing': the use of quantitative and qualitative methods to evaluate an exercise class and promote exercise for adults with mobility impairments.

PURPOSE: Physical inactivity in people with severe disabilities is common and has severe consequences. Conditioning classes are one way to increase activity and promote its health related outcomes. This paper reports the results of an evaluation of a community based conditioning class for adults with mobility impairments. METHOD: The study uses two methods with two samples: a quantitative self-report methodology and a quantitative interview. RESULTS: The quantitative evaluation found no significant increases in standard self-report measures of physical activity, functional status, quality of life, depression, or exercise self-efficacy. The lack of significant quantitative results may be due to limits in study design. The open-ended qualitative interviews with 16 class participants show important physical, social and psychological improvements. The juxtaposition of these two perspectives allows researchers to recognize the limitations in their choice of methods and the challenges faced by researchers evaluating small community based programmes for this limited population. CONCLUSION: In this case, the qualitative evaluation captured the positive experiences of the exercise class participants.

Adult↗

PubMed1989

Stable factors in chronic pain.

In an effort to identify components of the chronic pain experience, a sample of 444 chronic pain patients who had completed a battery of self-report measures was divided into two groups. The data from each group were analyzed using principal components analysis. Four factors emerged for one group of patients, which accounted for 57.6% of the variance and represented the dimensions of psychological distress, pain-related disability, pain description, and pain history. In the other group, five factors emerged that accounted for 64.2% of the variance. These factors represented psychological distress, disability, pain intensity, pain sensation, and pain history. The similarity of these factors across groups suggests that they represent stable dimensions of the patient's pain experience. Research implications and methodological considerations are discussed.

Adult↗

PubMed2006

A statistical methodology for analyzing co-occurrence data from a large sample.

Determining important associations among items in a large database is challenging due to multiple simultaneous hypotheses and the ability to select weak associations that are statistically but not clinically significant. The simple application of the chi2 test among all possible pairs of items results in mostly inappropriate associations surpassing the traditional (alpha=.05, chi2=3.94) threshold. One can choose a stricter threshold to find stronger associations, but the choice may be arbitrary. We combined the volume test of Diaconis and Efron with a p-value plot to select a more rigorous and less arbitrary threshold. The volume test adjusts the p-value of the chi2-statistic. A plot of adjusted p-values (1 - p versus N(p)), where N(p) is the number of test statistics with a p-value greater than p, should be linear if there are no true associations. The point where the plot deviates from a line can be used as a threshold. We used linear regression to select the threshold in a reproducible fashion. In one experiment, we found that the method selected a threshold similar to that previously obtained by manually reviewing associations.

Calibration↗

PubMed1993

Urothelial permeability of the isolated whole bladder.

The urothelium of the bladder presents an effective barrier to the penetration of solutes from the urine into the bladder wall. Previously, we have demonstrated that the dye indigocarmine can be utilized intravesically to study urothelial permeability. In general, intravesical indigocarmine (administered in vivo) will not penetrate the bladder wall unless the urothelium is damaged by overdistension, acetone administration, or mechanical damage. Unfortunately, using in vivo methodologies, one is limited in the study of the effect of specific conditions and permeations on bladder permeability. In the current study an isolated in vitro whole bladder model was developed to quantitatively study the permeability of the bladder urothelium. In these studies, the penetration of indigocarmine into and through the bladder wall was quantitated under various conditions. The in vitro bladder was filled by infusing 1% indigocarmine in saline in a step-wise manner at the rate of 10 ml in 10 minutes followed by a stabilization period of 10 minutes. Samples were taken from the bath at 20 minutes intervals for spectrophotometrical analysis of the dye. At the end of experiment the bladder was washed in saline for 10 minutes, and stored and extracted in formalin. In general, no indigocarmine penetrated the urothelium until the in vitro capacity was reached and exceeded. At intravesical volumes greater than capacity, the dye concentration in the bath increased very rapidly, even though the integrity of the bladder wall remained intact. In bladders treated with a gentle 50% acetone wash for 1 minute the dye started to penetrate into the bath at intravesical volumes of 25% of capacity and increased rapidly thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetone↗

PubMed2006

Influence of soil aging on sorption and bioavailability of simazine.

Characterization of pesticide bioavailability, particularly in aged soils, is of continued interest because this information is necessary for environmental risk assessment. However, pesticide bioavailability in aged soils has been characterized by a variety of methods with limited success, due in part to methodological limitations. The objective of this study was to use solvent extraction methods to correlate simazine residue bioavailability in aged soils to simazine mineralization using a simazine-mineralizing bacterium. Soils from Brazil, Hawaii, and the midwestern United States were treated with UL-ring-labeled [14C]simazine and incubated for up to 8 weeks. At the end of each incubation period, soils were either incubated further, extracted with 0.01 M CaCl2, or extracted with aqueous methanol (80:20 v/v methanol/water). In a parallel experiment, after each incubation period, soils were inoculated with the bacterium Pseudomonas sp. strain ADP, which is capable of rapidly mineralizing simazine, and 14CO2 was determined. The inoculated soil samples were then extracted with 0.01 N CaCl2 and with aqueous methanol. This allowed for the evaluation of the bioavailability of aged simazine residues, without the contribution of simazine desorption from soil. Results of these studies indicated that simazine sorption to soil increased with aging and that amounts of simazine in aged soils extracted by 0.01 M CaCl2 and aqueous methanol were highly correlated to amounts of simazine mineralized by Pseudomonas sp. strain ADP. Consequently, 0.01 M CaCl2/methanol-extractable simazine in aged soils can be used to estimate bioavailable residues. This technique may be useful in determining the bioavailability of other s-triazine compounds in soils.

Adsorption↗

PubMedDate not supplied

A simple index for representing the discrepancy between simulations of physiological pharmacokinetic models and experimental data.

The objective of this study was to develop an index that would provide a quantitative measure of the degree of discrepancy between simulations of physiologically based pharmacokinetic (PBPK) models and experimental data. The approach we developed involves the calculation of the root mean square of the error (representing the difference between the individual simulated and experimental values for each sampling point in a time course curve), and dividing it by the root mean square of the experimental values. The resulting numerical values of discrepancy measures for several data sets (each corresponding to an end point) obtained in a single experimental study are then combined on the basis of a weighting proportional to the number of data points contained in each data set. Such consolidated discrepancy indices obtained from several experiments (e.g., exposure scenarios, doses, routes, species) are averaged to get an overall discrepancy index, referred to as the PBPK index. This empirical index reflects the overall, weighted average percent difference between the a priori PBPK model simulations and experimental data. The proposed methodology is illustrated using previously published experimental and simulated data on dichloromethane pharmacokinetics in humans. The application of this kind of a "quantitative" method should help remove the ambiguity in communicating the degree of concordance or discrepancy between PBPK model simulations and experimental data.

Animals↗

PubMed1999

Shift work and sleep disorder among textile mill workers in Bahir Dar, northwest Ethiopia.

OBJECTIVE: To assess the length and quality of sleep among shift workers at Bahir Dar textile mill. DESIGN: A cross sectional study using structured questionnaire that contained sociodemographic variables, duration of work, work schedule, number of sleeping hours, sleep disorders, and associated reasons for such disorders. SETTING: A textile mill in Bahir Dar, northwest Ethiopia. SUBJECTS: Three-hundred ninety four random sample of production workers of the mill. OUTCOME MEASURES: Sleep disorders, and the impact of external and home environment on sleep. RESULTS: The mean duration of work in the factory was 25.4 +/- 7.1 years. Ninety-seven per cent of the study population work in a rotating eight hourly shift system. The mean number of hours a worker sleeps after a worked shift was 5.1 +/- 2.3. Two hundred thirty (58.4%) claimed to experience a sleep disorder. Sleep disturbance was significantly associated with rotating shift work, external environmental noise, and working in the spinning department. CONCLUSION: The majority of the workers in Bahir Dar textile mill experienced sleep disturbances as detailed in the study methodology.

Adult↗