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PubMed1993

Nationwide quality control trial on lymphocyte immunophenotyping and flow cytometer performance in Italy.

The Italian Society for Cytometry (Gruppo Italiano di Citometria, GIC) promoted this nationwide large-scale quality control trial on cellular immunophenotyping and flow cytometer performance in 1991. The aim of this independent study was to evaluate instrument performance with calibrated fluorescence microbeads (minimum threshold for FITC, linearity, coefficients of variation and resolution indexes for fluorescence), and to correlate it to the measurement of lyophilized lymphocyte surface immunofluorescence staining with a wide spectrum of antibodies (percentage of positive cells and fluorescence mean intensity). A single send-out was made to 306 laboratories with 350 instruments throughout Italy. Each kit included anonymous vials containing premixed calibrated microbeads, lyophilized human lymphocytes and small aliquots of conjugated monoclonal antibodies, for both single FITC and double FITC/PE staining. Participants were also asked to use their own anti-CD4 monoclonal. A valid answer was returned by 209 laboratories with 221 instruments. Gating was not an assay variable. The minimum sensitivity threshold for FITC ranged from 26.6 to 11,293 MESF, with marked instrument heterogeneity as far as the relationship between FITC threshold and coefficients of variation for fluorescence was concerned. A low FITC threshold also correlated with a good resolution index for low intensity stainings. No performance comparisons among instrument brands and models were made. The lyophilized lymphocyte analysis showed an overall frequency of outliers ranging from 3.2% to 19.7%, with a maximum for CD2 FITC (19.7%) and CD3 + HLA-DR + (12.1%). A strongly negative relationship was evident between the FITC threshold and the number of CD2+ cells, whereas the sensitivity threshold had virtually no effects on the measured level of higher antigen density markers like CD4 and many others. Absolute fluorescence intensity measurements of CD4+ and CD19+ were also made. This study design proved valid and suitable for a large-scale evaluation of both instrument performance and cytometer operators' skill. A number of practical problems were identified among participants, thus stressing the need for more effective educational programmes and technical guidelines.

Flow Cytometry↗
PubMed1995

Factors influencing safer sexual behaviors in heterosexual late adolescent and young adult collegiate males.

An exploratory study examined variables characterized as predisposing to the practice of safe sexual behaviors. A sample of 227 male subjects from a state-supported university in southeastern New England returned questionnaires anonymously that contained demographic questions and instruments to measure the study variables. After removing two variables for low internal consistency reliabilities, the remaining five were entered simultaneously into a multiple regression equation. The variables captured 21% of the variance. The direction and magnitude of the statistically significant standardized beta weights are as follows: attitude toward condoms, .41; internal health locus of control, .22; and self-esteem, -.16. These attitudes and characteristics can be incorporated into interventions to reduce sexual exposure to HIV.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Clinical trials in psychosocial medicine: methodologic and statistical considerations. Part I. Introduction.

Psychosocial oncology is defined as a newly developing field which requires its own methodology for measuring the importance of psychologic and social factors for cancer patients, their families, and involved health professionals. As with all new areas of research, there must be a systematic approach once clinical observations and initial hypotheses have been made. The science for such an approach has been slow to develop because of the complexities of finding and testing the appropriate instruments for identifying and quantifying variables before trying to improve the patient's adjustment. In order to facilitate this process, a five-center collaborative group has been formed. Among its first tasks are the selection and testing of screening instruments.

Clinical Trials as Topic↗
PubMed1990

[The effect of supportive nursing care on depression, mood and satisfaction in military patients with low back pain].

Support has always been considered an important nursing concept. However, there is no agreement among nurse researchers as to a conceptual definition of supportive nursing or meaningful supportive behaviors. Clarification of the concept, support in nursing, is necessary to promote communication among nurses on nursing behaviors that are effective in providing support and on understanding the relevant properties and characteristics of the concept, supportive nursing care. The objectives of the study were: 1. to analyze the concept, support in nursing, in order to provide a definition of supportive nursing care, and 2. to operationalize the definition of supportive nursing care and use it as an experimental nursing intervention for patients with low back pain. The first part of the study used the concept analysis approach developed by Walker and Avant (1983) to define the concept of supportive nursing care. The properties of supportive nursing care, defined by this analysis, included perception of supportive need, reciprocal interaction (Transaction), listening, providing empathy and information related to health, and confirmation of the patient's verbal and non-verbal response. The second part, the experimental part of the study, was done using King's(1970) Interpersonal Theory for Nursing. The concept, supportive nursing care, as defined in the concept analysis was operationalized and used as the experimental intervention. The experiment tested the effectiveness of the independent variable, supportive nursing care on the dependent variables, depression, mood and patient satisfaction, in the patients with low back pain in army hospitals. The instruments used to measure the dependent variables were Zung's(1965) Self-Rating Depression Scale, Ryman and Colleagues' (1974) Mood Questionnaire and LaMonica and Colleagues' (1986) Patient Satisfaction Scale. The experimental design used for this study was a Solomon 4 group experimental design. This design has the strength of allowing for observation of the main effects of supportive nursing care and pretesting, and for observation of the interaction effects of pretesting and supportive nursing care. The design includes one experimental group and three control groups. The Subjects of this study were 150 young male patients with low back pain on Neuro-Surgical Wards in three general army hospitals. There were 35 in the experimental group, 39 in the pre-posttest control group, 36 in the treatment-posttest control group and 40 in the posttest only control group. Supportive nursing care, as operationalized by the researcher according to the concept analysis, was given to the patients in the experimental group and the treatment-posttest control group, individually for 30 minute sessions, every other day for 5 days.(ABSTRACT TRUNCATED AT 400 WORDS)

Affect↗
PubMed2004

Comparative analytical costs of central laboratory glucose and bedside glucose testing: a College of American Pathologists Q-Probes study.

CONTEXT: One of the major attributes of laboratory testing is cost. Although fully automated central laboratory glucose testing and semiautomated bedside glucose testing (BGT) are performed at most institutions, rigorous determinations of interinstitutional comparative costs have not been performed. OBJECTIVES: To compare interinstitutional analytical costs of central laboratory glucose testing and BGT and to provide suggestions for improvement. DESIGN: Participants completed a demographic form about their institutional glucose monitoring practices. They also collected information about the costs of central laboratory glucose testing, BGT at a high-volume testing site, and BGT at a low-volume testing site, including specified cost variables for labor, reagents, and instruments. PARTICIPANTS: A total of 445 institutions enrolled in the College of American Pathologists Q-Probes program. MAIN OUTCOME MEASURE: Median cost per glucose test at 3 testing sites. RESULTS: The median (10th-90th percentile range) costs per glucose test were 1.18 dollars (5.59 dollars-0.36 dollars), 1.96 dollars (9.51 dollars-0.77 dollars), and 4.66 dollars (27.54 dollars-1.02 dollars) for central laboratory, high-volume BGT sites, and low-volume BGT sites, respectively. The largest percentages of the cost per test were for labor (59.3%, 72.7%, and 85.8%), followed by supplies (27.2%, 27.3%, and 13.4%) and equipment (2.1%, 0.0%, and 0.0%) for the 3 sites, respectively. The median number of patient specimens per month at the high-volume BGT sites was 625 compared to 30 at the low-volume BGT sites. Most participants did not include labor, instrument maintenance, competency assessment, or oversight in their BGT estimated costs until required to do so for the study. CONCLUSIONS: Analytical costs per glucose test were lower for central laboratory glucose testing than for BGT, which, in turn, was highly variable and dependent on volume. Data that would be used for financial justification for BGT were widely aberrant and in need of improvement.

Blood Glucose↗
PubMed1998

Validation of a handheld automated keratometer in adults.

PURPOSE: To evaluate the Nidek handheld automated keratometer and compare it with the manual Zeiss keratometer. SETTING: St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom. METHODS: Forty-five normal adult volunteers were included in the study. Three sets of randomized keratometry measurements were taken from both eyes of each adult, with both instruments by two independent observers. Readings included powers of the steep and flat meridians and axis of the flat meridian. The mean difference between the two instruments was calculated. The variance of each instrument was calculated for the axis, the steep and flat meridians, and the mean of the two meridians. RESULTS: There was no significant difference between the mean Nidek and Zeiss keratometry readings for the steep (0.015 mm; P = .167) or flat (0.054 mm; P = .069) meridian or axis measurements (P = .172). On repeated measurements, the within-subject and within-group variabilities, calculated separately for each instrument, were significantly less for the Nidek automated keratometer than the Zeiss keratometer (P < .01) when measuring the steep and flat meridians. There was however, a significant increase in axis variability using the Nidek keratometer (range 20 degrees; P < .01). CONCLUSION: The Nidek automated keratometer was accurate, reliable, and easy to use and compared favorably with the manual Zeiss keratometer when measuring corneal curvature. In the handheld mode, the Nidek is not suitable for axis measurements. It has the additional advantage of portability.

Adult↗
PubMed1997

Variability of DNA analysis by image cytometry. Bladder Tumor Marker Network.

Two laboratories equipped with CAS 200 (Becton Dickinson Image Cytometry Systems, San Jose, CA) instruments participated in this study of variability of DNA analysis of bladder tumor specimens. Formalin fixed paraffin embedded specimens were disaggregated and centrifuged onto microscope slides from ten bladder tumor specimens and two specimens of normal urothelium. Sources of variability considered were Specimen, Slide, Run, Laboratory, and Error. Slides were systematically scanned and 200 cells measured followed by the operator selecting 100 nuclei with abnormal morphology. DNA index (DI) and hyperdiploid fraction (HDF) were calculated from the DNA frequency distributions. For systematic sampling, 92% of the variability was due to Specimen indicating that differences in HDF values between specimens reflect biological differences. With selective sampling, only 67% of the variability in HDF is due to Specimen differences. Other factors, Laboratory, Error, and Laboratory x Specimen interaction each accounted for approximately 10% of the variability. Similarly variability of DI with selective sampling was also higher, and less specimen dependent than systematic sampling. It is important that sampling schemes and selection criteria be carefully documented in order to control variability. Enriched (or selective) sampling for abnormal cells has the potential to increase sensitivity but specimen classification based on these measurements must depend on determination of the frequency of such cells in the total population.

Analysis of Variance↗
PubMed1987

Tendon reflex variability and method of stimulation.

Human tendon reflexes show large fluctuations, even when accurate mechanical instruments are used for stimulation. To examine the contribution of stimulus factors to reflex variability two methods of stimulation were compared in healthy subjects. One method consisted of a normal hand-held reflex hammer, with a transducer to measure stimulus intensity. The results with this hammer, both after maximal stimuli and after stimuli over a wide range of intensities, showed a similar variability of reflexes as with a more accurate instrumental stimulator. In previous studies in human subjects an equal or larger variability of reflexes was found. It is concluded that for many applications a simple hand-held reflex hammer gives equally reliable results as more complicated instrumental stimulators.

Adult↗
PubMed1997

Precision and discriminatory ability of calcaneal bone assessment technologies.

To determine if measuring skeletal status at the calcaneus is a potentially valuable technique for diagnosing osteoporosis, we examined five calcaneal assessment techniques in 53 young normal women and 108 postmenopausal women with osteoporosis and compared these measurements to dual-energy X-ray absorptiometry (DEXA) at the calcaneus, hip, and spine. The five instruments, including single-energy X-ray absorptiometry (SEXA) and four quantitative ultrasound (QUS) instruments, were evaluated for precision, ability to discriminate osteoporotic from young normal subjects, and correlation to the other instruments. The coefficient of variation (%CV) for instrument, positioning, interobserver, and short-term precision of the five calcaneal instruments ranged from 1.34-7.76%, 1.63-7.00%, 1.84-9.44%, and 1.99-7.04%, respectively. The %CVs for positioning, interobserver, and short-term precision were similar for calcaneal DEXA, calcaneal SEXA, and stiffness (as measured by Achilles). The %CVs for instruments precision were similar between calcaneal DEXA and SEXA. The ability of the five calcaneal instruments to discriminate osteoporotic from young normal subjects was similar based on the analysis of area under the receiver operating characteristic curves (range 0.88-0.93) and equivalent to DEXA of the calcaneus and hip (0.88-0.93). The correlations between the measurements of five calcaneal instruments were strong (0.80 < or = r < or = 0.91, p < 0.001). These data suggest that although the precision is variable, the calcaneal QUS and SEXA instruments can discriminate between osteoporotic patients and young normal controls and appear to be a useful technique for assessment of osteoporosis.

Absorptiometry, Photon↗
PubMed1996

Comparison of acoustic immittance measures obtained with different commercial instruments.

Three acoustic admittance measurements (tympanometric peak pressure, peak compensated static acoustic admittance, and tympanometric width) were compared across seven commercially available acoustic immittance systems. Forty-nine adult subjects (45 females and 4 males), 16 to 50 years of age (mean = 27.7 years), with normal middle ear function participated in this investigation. Small but statistically significant differences were observed for each of the tympanometric variables for several of the instruments evaluated. In most instances, the differences were small enough that the same normative data could be applied across the instrumentation employed in this study; however, there were two measurement conditions, peak compensated static acoustic admittance and tympanometric width, where, for selected instruments, the range in values differed by an amount great enough to warrant consideration in clinical decision making.

Acoustic Impedance Tests↗
PubMed1992

Stability over time of character assessment using a psychodynamic instrument and personality inventories.

In a group of patients with a preoperative diagnosis of ulcerative colitis, the stability of character traits and modes of mental functioning were studied after a major life event, major abdominal surgery, using the Karolinska Psychodynamic Profile (KAPP), an interview-based assessment instrument founded upon psychoanalytic theory. In addition, different personality and temperamental variables were assessed with 2 self-report instruments. The patients were assessed before surgery, and follow-up was made at least 1 year after their final scheduled surgery. Although the patients had undergone major abdominal surgery and convalescence between the assessments, the correlations between the scores before and after surgery were very high, and the levels of the scores were very similar. This was true for all the instruments, indicating that they assessed stable characteristics in the patients. The changes that did occur were mainly in the predicted direction. The results of this study suggest that the KAPP can assess modes of mental functioning and character traits that are relatively stable and only slowly variable.

Adaptation, Psychological↗
PubMed2004

The relationship between hand size and difficulty using surgical instruments: a survey of 726 laparoscopic surgeons.

BACKGROUND: Hand size is an important variable to consider when designing hand tools. Laparoscopic surgical instruments have been reported to cause hand and upper extremity discomfort. This study investigates the correlation between surgical glove size, preexisting musculoskeletal problems, and difficulty using laparoscopic instruments. METHODS: Approximately 11,000 questionnaires were sent to SAGES, AAGL, and AWS members. Questions included basic demographic and practice data, surgical glove size, the presence of musculoskeletal problems, and the perceived difficulty using several types laparoscopic instruments. There were 726 responses (from 159 women and 567 men). Subjects were grouped by hand size (Small < or =6.5, Medium 7.0-7.5, Large >7.5; female group only: Small < or =6.0, Medium 6.5, Large >6.5). ANOVA was used to test for differences between groups. RESULTS: The percentage of time subjects reported having difficulty using all laparoscopic instruments was greater for the Small glove size group compared to both the Medium and Large groups ( p < 0.001). In females, the scissors and staplers were more difficult to use for the Small and Medium glove size group compared to the Large group ( p < 0.001). Subjects who reported musculoskeletal problems ( n = 145) performed a significantly greater percent of laparoscopic cases and found the stapler and graspers difficult to use for a greater percentage of time than those not reporting problems ( n = 559). CONCLUSION: Hand size is a significant determinant of difficulty using laparoscopic surgical instruments. Individuals using glove sizes 6.5 or smaller experience significantly more difficulty using common laparoscopic instruments, and in particular laparoscopic staplers. Manufacturers of surgical hand tools should consider hand size when designing future surgical instruments.

Adult↗
PubMed1989

Statistical evaluation of agreement between two methods for measuring a quantitative variable.

Methodologic research is often concerned with determining whether two methods (procedures, laboratory instruments) can be used interchangeably for measuring some quantitative variable of interest. Logically, one method can be used as a surrogate of another provided the methods show high agreement on the measured results. Although the product-moment correlation (r) is often used as an indicator of agreement, this index is in fact inappropriate for this purpose. The intraclass correlation (r1) is the correct statistic for assessing agreement or consistency between two methods. Another criterion sometimes used for supporting interchangeability is the similarity of the mean measured results obtained by the two methods. However, similarity of means (aggregate agreement) does not necessarily indicate individual-subject agreement, and it is the latter that is the pre-requisite for interchangeability. On the other hand, a marked difference between two means (lack of aggregate agreement) does necessarily indicate lack of individual-subject agreement and therefore non-interchangeability. Herein we suggest that two methods for measuring a quantitative variable can be judged interchangeable provided all of the following conditions are met: first the methods must not exhibit marked additive or nonadditive systematic bias; second the difference between the two mean readings is not "statistically significant"; third, the lower limit of the 95% confidence interval of the intraclass correlation is at least 0.75. Statistical procedures to evaluate these conditions of interchangeability are described in detail. A computer program coded in SAS to carry out the procedures is listed in the Appendix. A similar program coded in DBASE III PLUS for the microcomputer is available upon request.

Analysis of Variance↗
PubMed2000

A comparison of two nickel-titanium instrumentation techniques in teeth using microcomputed tomography.

AIM: The aim of the study was to compare the shaping of root canals by two nickel-titanium instrumentation techniques using microcomputed tomography (MCT). METHODOLOGY: Ten mandibular first molar teeth (30 canals) that had intact crowns and fully formed roots were scanned using MCT. Fifteen canals were instrumented using NiTiFlex hand files (Maillefer) using balanced force. The remainder were instrumented using prototype ProFile 0.04 Taper instruments (Dentsply) in a crown-down manner to an apical size ISO 25. The teeth were scanned again following instrumentation. The two instrumentation techniques were compared in a total of 27 canals. The area of dentine removed at predetermined levels (2.0, 3.0, 4.5, 6.0, 7.5 mm) from the apex was measured. Transportation and centring were recorded. Images constructed at these levels were compared with video images of equivalent physical sections created after the second scan. The volume of dentine removed in the apical 7.5 mm of the root canals of each tooth was calculated and the different techniques compared. Rendered three-dimensional images were used to assess the preparations qualitatively. The time taken for preparation was recorded. RESULTS: There was no significant difference between hand instrumentation with NitiFlex files and machine instrumentation with prototype ProFile 0.04 Taper instruments for any of the variables tested. CONCLUSIONS: Both techniques produced well centred and tapered preparations.

Dental High-Speed Technique↗
PubMedDate not supplied

Predicting follow-up functional outcomes in outpatient rehabilitation.

Functional outcomes at an average of six months after outpatient rehabilitation were investigated in a pilot study with a sample of 42 patients receiving physical therapy for low back, neck, and other musculoskeletal problems. Logistic regression analyses were used to study variables related to the achievement of a predetermined level of physical functioning or to whether improvement occurred from initial to follow-up assessment. Scales used in the analyses were obtained from two measures of functioning, the Medical Outcomes Trust Short Form 36 (SF-36) and the Medical Rehabilitation Follow Along (MRFA instrument). Demographic and program characteristic variables obtained from clinic records were also included in the analyses. The independent variables entered into two groups of regression equations included age, gender, presenting problem, workers' compensation coverage, functioning at initial assessment, number of visits, length of program, and intensity of program. For the SF-36, the General Health scale and presenting problem predicted above or below a level greater than one standard deviation less than the mean on the Physical Functioning scale at follow-up. The combination of the Role Physical and Role Emotional scales predicted follow-up level on the Physical Component Summary (PCS) scale. The interaction of age and intensity of treatment was predictive for both the Physical Functioning and PCS scales. For predicting improvement or no improvement using the SF-36 scales, General Health and the interaction between age and intensity were predictive of change on the Physical Functioning scale, whereas age and the interaction between age and number of visits were predictive of change on the PCS scale. For the MRFA instrument, the interaction between age and the intensity of treatment was predictive for both a predetermined level of physical functioning and amount of improvement in physical functioning at follow-up. An intensity rating of pain and a measure of affective distress at initial assessment both improved the identification of patients at risk for not reaching a given level of functioning, whereas treatment intensity improved the identification of those patients at risk for not showing improvement at follow-up. Length of time between the end of outpatient therapy and follow-up assessment was generally not related to follow-up physical functioning. Interpretation and implications of these findings, as well as applications of this analytic approach to outcomes assessment, are discussed.

Activities of Daily Living↗
PubMed2000

Evaluating nursing administration instruments.

OBJECTIVE: To identify and evaluate available measures that can be used to examine the effects of management innovations in five important areas: autonomy, conflict, job satisfaction, leadership, and organizational climate. BACKGROUND: Management interventions target the context in which care is delivered and through which evidence for practice diffuses. These innovations need to be evaluated for their effects on desired outcomes. However, busy nurses may not have the time to locate, evaluate, and select instruments to measure expected nursing administration outcomes without research-based guidance. Multiple and complex important contextual variables need psychometrically sound and easy-to-use measurement instruments identified for use in both practice and research. METHOD: An expert focus group consensus methodology was used in this evaluation research to review available instruments in the five areas and evaluate which of these instruments are psychometrically sound and easy to use in the practice setting. RESULTS: The result is a portfolio of measures, clustered by concept and displayed on a spreadsheet. Retrieval information is provided. The portfolio includes the expert consensus judgment as well as useful descriptive information. CONCLUSIONS: The research reported here identifies psychometrically sound and easy-to-use instruments for measuring five key variables to be included in a portfolio. The results of this study can be used as a beginning for saving time in instrument selection and as an aid for determining the best instrument for measuring outcomes from a clinical or management intervention.

Conflict, Psychological↗
PubMed1997

Assessing normal embryogenesis in Caenorhabditis elegans using a 4D microscope: variability of development and regional specification.

Caenorhabditis elegans is renowned for its invariant embryogenesis. This pattern of development is in apparent contrast to other organisms from Drosophila to higher vertebrates. With the aid of a 4D microscope system (multifocal, time-lapse video recording system) which permits the extensive documentation and analysis of cell divisions, cell positions, and migrations in single embryos we have analyzed normal embryogenesis of C. elegans. The instrumentation reveals a naturally occurring variability in cell division timing, cell positioning, and cell-cell contacts which could not have been detected by the direct observation used earlier (Sulston et al., 1983, Dev. Biol. 100, 64-119). Embryos are very flexible and produce an essentially invariant premorphogenetic stage from variable earlier stages. An analysis of the distribution of the descendants of the early founder blastomeres at the premorphogenetic stage shows that these establish discrete regions in the embryo, a process involving a considerable amount of cell movement, which again varies in different embryos. Only cell fate assignment remains invariant. However, as shown earlier, this is not due to an autonomous invariant specification of cell fates but due to the fact that cell-cell interactions occur very early when the topology of blastomeres in the embryo is still sufficiently precise to ensure reproducible patterns of inductions. A new concept that founder blastomeres produce embryonic regions in the embryo can explain the striking complexity of the lineage per se and also the complicated asymmetric lineage patterns by which the bilateral symmetry of the embryo is established. Many cells, including bilateral homologs, were apparently chosen for a specific fate solely by their position in the embryo, irrespectively of the lineage descent by which the cells are created. We postulate that the production of regions by cell-cell interactions is the pivotal principle guiding the embryogenesis of C. elegans and that the embryogenesis of the worm follows the same basic principles as embryogenesis in other organisms.

Animals↗