Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “instrumental variable”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMedDate not supplied

[Domestic violence as a factor associated to women's health problems].

OBJECTIVE: To study the impact of intimate partner violence (IPV) on women's physical and psychological health. DESIGN: Cross-sectional study. SETTING: Primary care centers in 3 Andalusian provinces. PATIENTS: A total of 425 women, aged 18 to 65 years, were recruited following the same randomisation process in 6 primary care centers. MEASUREMENTS: A self-administered structured questionnaire for this study was used to gather the information. As well as sociodemographic variables, the instrument included questions about IPV, physical health indicators (chronic disease and type, lifetime surgeries, days in bed), psychological health (psychological morbidity, use of tranquilizers, antidepressants, pain killers, alcohol and recreational drugs), self-perceived health and social support. RESULTS: Of 425 women, 31.5% ever experienced any type of partner violence. Women experiencing IPV were more likely to suffer a chronic disease. IPV was significantly associated with a number of adverse health outcomes, including spending more than 7 days in bed in the last three months (ORa=2.96; CI 95%, 1.00-8.76), psychological morbidity (ORa=2.68; CI 95%, 1.60-4.49) and worse self-perceived health (ORa=1.89; CI 95%, 1.04-3.43), after controlling for potential confounding variables. CONCLUSION: This study shows that ever experiencing IPV is associated with a worse psychological and self-perceived health. Physical injuries are not the only "evidence" of the presence of IPV. Primary health care professionals are in a privileged position to help women who are abused by their partners.

Adolescent↗
PubMed2004

Calibration and validation of confocal spectral imaging systems.

BACKGROUND: Confocal spectral imaging (CSI) microscopic systems currently on the market delineate multiple fluorescent proteins, labels, or dyes within biological specimens by performing spectral characterizations. However, some CSI systems have been found to present inconsistent spectral profiles of reference spectra within a particular system and between related and unrelated instruments. This variability confirms that there is a need for a standardized, objective calibration and validation protocol. METHODS: Our protocol uses an inexpensive multi-ion discharge lamp (MIDL) that contains Hg(+), Ar(+), and inorganic fluorophores that emit distinct, stable, spectral features in place of a sample. We derived reference spectra from the MIDL data to accurately predict the spectral resolution, ratio of wavelength to wavelength, contrast, and aliasing parameters of any CSI system. We were also able to predict and confirm the influence of pinhole diameter on spectral profiles. RESULTS: Using this simulation, we determined that there was good agreement between observed and theoretical expectations, thus enabling us to identify malfunctioning subsystems. We examined eight CSI systems and one nonconfocal spectral system, all of which displayed spectral inconsistencies. No instrument met its optimal performance expectations. In two systems, we established the need for factory realignment that had not been otherwise recognized. CONCLUSIONS: We found that using a primary light source that emits an absolute standard "reference spectrum" enabled us to diagnose instrumental errors and measure accuracy and reproducibility under normalized conditions. With this information, a CSI operator can determine whether a CSI system is working optimally and make objective comparisons with the performance of other CSI systems. We determined that, if CSI systems were standardized to produce the same spectral profile of a MIDL lamp, researchers could be confident that the same experimental findings would be obtained on any CSI system.

Animals↗
PubMed1993

Optimization of peroxide production by resident macrophages.

Previous reports indicated that resident macrophages produced low or nondetectable quantities of H2O2 (1-10 nmol H2O2/mg resident macrophage protein) when measured by the phenol red assay described by Pick and Mizel [5]. However, modifications of the assay that included addition of calcium to assay solutions, alterations in cell-harvesting methods, increasing the concentration of cells analyzed, incubating the cells in ambient air, and enhancing the interactions between macrophages and particulate stimulants by centrifugation resulted in increased production of peroxide. Each variable was instrumental in improving the assay conditions and the combination of changes dramatically increased the amount of peroxide (30-60 nmol H2O2/mg resident macrophage protein) obtained from murine resident macrophages, making it possible to better assess the role of these cells in microbicidal killing.

Animals↗
PubMed2006

Interactive technologies and videotapes for patient education in cancer care: systematic review and meta-analysis of randomised trials.

GOALS OF WORK: Patients diagnosed with cancer need education as they face complex decisions. There is limited evidence about the impact of new educational technologies for cancer patients. This paper investigates whether interactive technologies and videotapes for patient education in cancer care improve knowledge, satisfaction or other outcomes. METHODS: Literature search of five computerised databases (Medical Literature Analysis and Retrieval System, Excerpta Medica Database, Cumulative Index to Nursing and Allied Health Literature, Cochrane Controlled Trials Register and Cochrane Database of Systematic Reviews) and bibliography searches identified relevant randomized controlled trials. Two reviewers independently assessed trial quality. Summary effects for knowledge and satisfaction were calculated using random-effects models (RevMan 4.2 software). Continuous data were summarised as weighted mean differences and dichotomous data as odds ratios, each with their respective 95% confidence interval. Standardised effect sizes for these outcomes were calculated and contrasted. RESULTS: Nine randomised control trials with 1,678 patients were identified. Three evaluated the use of videotapes, and six evaluated computer technologies. Studies were of good-quality design but were variable in instruments, content, populations, outcomes and results. Educational technologies showed improved patient knowledge (effect sizes ranging from 0.12 to 1.03). Satisfaction was improved in some studies, but the overall effect was more equivocal--effect sizes ranged (0.05 to 0.40) of benefit for knowledge and from 0 to 0.40 for satisfaction. CONCLUSIONS: The trials present preliminary evaluations of the technology in North America, the UK and Australia. There is a trend to improved knowledge and satisfaction. The ways in which the interventions are delivered and the extent of communication with a health professional affect patient responses.

Computer-Assisted Instruction↗
PubMed1992

Self-reported anger in black high school adolescents.

The purpose of this study was to explore the recognition and expression of anger in black high school adolescents. A total of 56 teens, aged 14-19 years, responded to questions about their recognition of anger, how and to whom they express anger, and to whom they refrain from expressing anger. They also stated their opinions about acceptable and unacceptable expressions of anger and its relationship to depression or suicide. Data were analyzed using frequency tabulations for all questions on the survey instrument. Specific variables of age, grade in school, gender, and family composition were analyzed by one-sample chi 2 tests (alpha set at 0.05). The study demonstrated 1) all the teens surveyed could recognize when they were angry; 2) most teens expressed anger to their friends, to their siblings, and to their mothers; 3) younger teens (ages 14-15 years) when compared to older teens (ages 18-19 years), identified mother as the one who made them angry; 4) females were more likely to feel like crying when angry; 5) females were more likely to feel like being silent when angry; 6) students from one- and two-parent homes did not differ in their expression of anger. Implications of this study include the recognition that anger is a natural, human emotion. Adolescents need to observe adults who can effectively manage behavior associated with anger. Problem solving skills, stress management techniques, and role play situations can be utilized as effective tools in the recognition and expression of anger in acceptable ways and in attempts at the prevention of dysfunctional anger.

Adolescent↗
PubMed2005

In-line radiofrequency ablation to minimize blood loss in hepatic parenchymal transection.

BACKGROUND: Intraoperative blood loss has been shown to be an important factor correlating with morbidity and mortality in liver surgery. A 5-cm long instrument with variably deployable metal electrodes using in-line radiofrequency ablation (ILRFA) energy was used for hepatic transection in an attempt to reduce bleeding. METHODS: Eight patients underwent liver resection. At each resection, half the resection was performed with ILRFA and the other half was performed with an ultrasonic aspirator alone. Blood loss was measured for each mode of resection. RESULTS: The mean blood loss using ILRFA was 6.5 (+/-3.7) mL/cm(2) compared with 20.4 (+/-8.7) mL/cm(2) by using the ultrasonic aspirator (P = .004). CONCLUSIONS: In-line radiofrequency ablation reduced bleeding during hepatic parenchymal transection when compared with the ultrasonic aspirator.

Aged↗
PubMed2006

Influence of nutrition attitudes and motivators for eating on postpartum weight status in low-income new mothers.

OBJECTIVE: The purpose of this study was to identify attitudes about nutrition and their influence on weight status in low-income mothers in the first year postpartum. DESIGN: Nutrition attitudes were assessed at 1.5, 6, and 12 months postpartum. Body weight was measured at each time point and height at 1.5 months to calculate body mass index. Nutrition attitudes at each time were compared with demographic variables and weight status. SUBJECTS: Subjects were 340 non-Hispanic white (31.3%), non-Hispanic black (25.1%), and Hispanic (43.7%) new mothers (mean age=22.4 years) located in central Texas. Criteria for participation included good health at delivery and low income (</=185% federal poverty guideline). STATISTICAL ANALYSES: chi(2) tests were used to compare demographic groups to categorical variables. Multivariate analysis of variance was done to investigate the effect of demographic variables on instrument subscale scores. A repeated-measures analysis of variance was used to identify significant changes over time. RESULTS: Obese women had higher barriers to healthful eating subscale means at 1 year compared with normal and overweight subjects at 1.5 and 6 months, and had more barriers than overweight participants at 12 months. Obese individuals also had higher emotional eating subscale scores than did overweight women at 1.5 months and both normal and overweight subjects at 12 months. CONCLUSIONS: Women who were obese at 1 year postpartum were more likely to perceive more barriers to healthful eating and respond more to emotional cues to eat. Health professionals could emphasize potential changes and difficulties often faced in postpartum and identify techniques to overcome these obstacles to healthful eating.

Adult↗
PubMed2003

Satisfaction with medical rehabilitation in patients with orthopedic impairment.

OBJECTIVE: To examine patient satisfaction after orthopedic impairment at 80 to 180 days after inpatient rehabilitation. DESIGN: Retrospective design examining records from facilities subscribing to the Uniform Data System for Medical Rehabilitation (UDSmr). SETTING: Information submitted to UDSmr from 1997 to 1998 by 177 hospital and rehabilitation facilities from 40 states. PARTICIPANTS: The sample (N=7781) was 72.63% female and 88.60% non-Hispanic white, with a mean age +/- standard deviation of 73.07+/-11.81 years, and average length of stay (LOS) of 13.84+/-10.48 days. INTERVENTION: Usual rehabilitation care. Main outcome measures Level of satisfaction 80 to 180 days after discharge as well as motor, cognitive, and subscale ratings for the FIM trade mark instrument. Predictor variables included gender, age, English language, marital status, discharge setting, LOS, rehospitalization, FIM gain, and primary payer. RESULTS: A logistic regression model was used to predict patient satisfaction at follow-up. Five statistically significant (P<.05) variables were found and correctly classified 94.9% of the patients. Discharge motor FIM rating, rehospitalization, age, patient's primary language, and discharge setting were associated with increased satisfaction. Discharge motor FIM ratings were significantly associated with increased satisfaction in patients with joint replacements and lower-extremity fractures. CONCLUSION: unctional and demographic variables were identified as predictors of satisfaction in patients with orthopedic impairments.

Aged↗
PubMed1990

Factors influencing the performance of peptide mapping by reversed-phase high-performance liquid chromatography.

Factors controlling the performance of peptide mapping on reversed-phase columns were systematically evaluated. Performance criteria included resolution (peak capacity and selectivity), system reproducibility, sensitivity and analysis speed. Column configuration, characteristics of packing materials, mobile phase composition, operating variables and instrumental designs were found to influence the performance of peptide mapping. Considerations for peptide identification techniques are discussed.

Chromatography, High Pressure Liquid↗
PubMed2002

Patient-related barriers to fatigue communication: initial validation of the fatigue management barriers questionnaire.

Fatigue is a highly prevalent and distressing symptom of cancer and its treatment. However, cancer patients often fail to communicate with their oncologists about fatigue. In this study, we attempted to identify the patient-related barriers to communication about fatigue, as cited by patients. Two hundred patients were sampled across the Community Cancer Care, Inc. (CCC) network of Indiana using the Cancer Behavior Inventory-Brief scale (CBI-B), the Zung Self-Rating Depression Scale (ZSDS), the Functional Assessment of Cancer Inventory-Fatigue scale (FACT-F), and the Fatigue Management Barriers Questionnaire (FMBQ), a questionnaire devised by experts in the field of cancer-related fatigue. There were no significant correlations between the instrument scores and demographic variables. Scores on the instruments did not differ significantly based on whether the patient was from a rural or urban site. One hundred thirty-two patients (66%) reported that they had never spoken to their doctor about fatigue. The most frequently reported reasons for this lack of patient communication about fatigue included the doctor's failure to offer interventions (47%), patients' lack of awareness of effective treatments for fatigue (43%), a desire on the patient's part to treat fatigue without medications (40%), and not wanting to complain to the doctor (28%). Patients reported that medical staff offered a mean of 11.63 recommendations for dealing with fatigue. The FMBQ was found to correlate significantly with self-efficacy (CBI-B, r = -0.20, P < 0.01) and correlate weakly with the number of recommendations made (r = -0.15, P < 0.05). The FMBQ was noted to have acceptable internal consistency (alpha = 0.88) and validity and may prove to be a useful instrument for understanding why patients do not communicate about fatigue. Multiple barriers contribute to why cancer patients do not comment about fatigue but may be overcome if physicians screen and assess for this symptom.

Aged↗
PubMed2002

Research designs for advanced practice nursing outcomes research.

Since 1992 there has been a growing demand for health care providers to justify their interventions and for health care systems to evaluate "quality" of care in terms of improving patients' lives and the cost of care provided. It often seems overwhelming when one looks at the wide range or variables and instruments that have been used in the name of outcomes research. This article describes various aspects of the research design for advanced practice nursing research. Explored are the topics of identifying researchable problems, developing research questions, selecting research designs, measuring concepts of interest, analyzing results, and designs for future outcomes research.

Humans↗
PubMed1997

Cathodic stripping voltammetric determination of doxazosin in urine and pharmaceutical tablets using carbon paste electrodes.

Several voltammetric techniques were used to explore the reductive behaviour of the antihypertensive agent doxazosin on a bare carbon paste (CPE) and a Tenax-modified carbon paste electrode (TMCPE). The results indicate that the process is irreversible and fundamentally controlled by adsorption, which allows doxazosin to be accumulated at the electrode surface. The cathodic adsorptive stripping (AdS) response was evaluated with respect to pH, accumulation variables and instrumental parameters, using differential-pulse (DPV) and square-wave voltammetry (SWV) as redissolution techniques. In both cases, a voltammetric peak close to 0 V in Britton-Robinson buffer (pH 6.6) was obtained after a preconcentration step at 0.55 V for 3 min (2000 rpm) and a subsequent cathodic scan. When the TMCPE was used, the limits of detection were 4.35 x 10(-11) and 5.18 x 10(-11) M for AdS-DPV and AdS-SWV, respectively. The deposition time (3 min) was improved relative to that obtained by means of CPE (6 min). Under the optimum operational conditions, the doxazosin reduction peak showed a linear response in the range from 6 x 10(-11) to 1 x 10(-9) M by using AdS-DPV, with an RSD of 3.39% for 3 x 10(-8) M doxazosin solution (n = 10). A method was developed for the determination of doxazosin in human urine and formulations.

Adsorption↗
PubMed2000

Adsorptive stripping voltammetric determination of ketoconazole in pharmaceutical preparations and urine using carbon paste electrodes.

The oxidation of ketoconazole on a bare carbon paste electrode was studied voltammetrically. The results indicated that the process is irreversible and controlled by an adsorption-extraction process which allows the accumulation of the drug at the electrode surface. After the optimization of solution pH, accumulation variables and instrumental parameters, sensitive differential pulse and linear sweep voltammetric peaks were obtained whose peak currents were linearly proportional to the ketoconazole concentration over the ranges 2.4 x 10(-8)-4.8 x 10(-7) and 9.1 x 10(-7)-1.0 x 10(-5) M, respectively. Based on these findings, a simple procedure was developed for the determination of ketoconazole in human urine and formulations.

Antifungal Agents↗
PubMed2001

Factors influencing the antibiotic-prescribing decisions of nurse practitioners.

Decision-making about treatment options is a complex process that is influenced by many variables. An instrument for studying this decision-making process and the factors influencing it was designed. A survey of the antibiotic-prescribing practices of nurse practitioners (NPs) was then conducted via mail and the World Wide Web. NPs who treat adult patients were presented with scenarios in which antibiotic prescription would be an appropriate choice. Participants were asked to evaluate the clinical scenarios and describe their decision-making about treatment and the rationale for treatment. Responses were analyzed to determine the factors that played a role in antibiotic decision-making and their relative importance in that process. The ranks of categories of factors by the respondents were similar across the 4 scenarios. Antibiotic-prescribing patterns and the rationale of the antibiotic-prescribing decision of the respondents for the presented scenarios are also described.

Adult↗
PubMed1994

Sleep patterns are disturbed in cats infected with feline immunodeficiency virus.

Human immunodeficiency virus (HIV)-related sleep disturbances have been reported early in AIDS. Likewise, the feline immunodeficiency virus (FIV), a natural lentivirus pathogen of cats, produces a similar immunodeficiency syndrome with neurological sequelae. To identify the neurophysiological substrate of FIV infection in brain, pathogen-free cats were infected with the Maryland strain of FIV. Eight weeks after inoculation, all FIV-infected cats seroconverted and virus was detected in the cerebrospinal fluid and in the mononuclear cells of peripheral blood. Ten to 12 months after the FIV inoculation, inoculated and control cats were surgically implanted with electrodes to record the sleep/wake cycle. These sleep recordings were obtained under conditions controlling for environmental variables and instrumental adaptation. FIV-infected cats spent 50% more time awake than the sham-inoculated controls and exhibited many more sleep/waking stage shifts--i.e., 40% more than controls. In addition, FIV-infected cats showed approximately 30% of rapid eye movement (REM) sleep reduction compared to controls. The latency to sleep and REM sleep onset was also significantly delayed in FIV-infected cats. In addition, a remarkable increase in cortically recorded spindle activity (8-13 Hz) was observed during slow-wave sleep in some infected subjects, similar to changes described in HIV-infected humans. Moreover, infected cats exhibited no overt signs of systemic morbidity, such as hyperpyrexia or body weight loss. These results indicate that FIV-infected cats exhibit sleep abnormalities similar to the sleep disturbances previously described in AIDS patients and further support the feline preparation as a valuable animal model of HIV infection of the central nervous system.

Animals↗
PubMed2000

Outcome measures for complex regional pain syndrome type I: an overview in the context of the international classification of impairments, disabilities and handicaps.

PURPOSE: To determine the availability of relevant and objective outcome measures concerning complex regional pain syndrome type I (CRPS I) for rehabilitation medicine. METHOD: Outcome measures were classified according to the International Classification of Impairments, Disabilities and Handicaps. For each outcome measure a description of concept, operationalization into variables and instrument was given. We performed a PUBMED MEDLINE search (1980-1998) using the following keywords: complex regional pain syndrome, reflex sympathetic dystrophy, impairment, disability, handicap, (long-term) outcome and effect/efficacy. RESULTS: Most outcome measures were concentrated on impairments, whereas measures at the level of disabilities and handicaps, the most relevant levels for rehabilitation medicine, were mentioned in very few studies. Objective outcome measures were merely found at the level of impairment. CONCLUSION: The results indicate a need for the development of relevant outcome measures at the level of disabilities and handicaps that can objectively measure treatment efficacy for CRPS I.

Activities of Daily Living↗
PubMed2005

Psychometric and administrative properties of measures used in assistive technology device outcomes research.

Although there have been numerous calls for increasing the quantity and quality of assistive technology outcomes research, no one has analyzed the nature of data that the field has been accumulating. This article summarizes our evaluation of 82 outcome studies, published between 1980 and 2001, addressing assistive technology devices (ATDs). Our data indicate that the "typical" ATD outcomes study published in the past 20 years is one that (a) used a sample population that was diverse in terms of age, disability population, and type of ATD being used; (b) measured user-reported dependent variables with instruments designed specifically for the study; (c) did not report adequate information on the reliability and validity for the measurement instruments that were used; (d) did not discuss the staff workload associated with learning, administering, and scoring its data collection tools; and (e) did not differentiate its findings in terms of distinguishable participant subgroups. Several suggestions are provided to guide future development of assistive technology outcome measures in the domains of usability, quality of life, and social role performance. In addition, seven recommendations are offered to outcomes researchers, policy makers, journal editors, and reviewers in order to improve the reporting of assistive technology outcomes research.

Adolescent↗