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At least 19 recordsLinked to original sources
PubMed1989

Assessment of the scatter fraction evaluation methodology using Monte Carlo simulation techniques.

To evaluate scatter fraction and scatter pair spatial distribution, experimental methods are generally used. These methods make use of a line source, placed along the FOV axis, inserted in a cylindrical phantom filled with air or water. The accuracy of these experimental methodologies can be tested by the use of a Monte Carlo method. In fact, the simulation allows the shape of the scatter event projection and the scatter fraction to be defined. An example of this application is the simulation package PETSI (PET SImulation). In this paper the comparison between the predicted scatter fraction and the experimentally evaluated one, obtained using an ECAT III PT 911/02 double ring whole body scanner are presented. PETSI permits additional data to be obtained: a) the true and scatter component of the energy spectrum; b) the spatial distribution, in the FOV plane, of the detected scatter events at different energy thresholds; c) the scatter to total detected events ratio; d) the predicted scatter fraction at both energy thresholds and FOV diameters. This information is very useful for optimizing both energy threshold and FOV size and to improve the accuracy of the currently used methods for the scatter fraction evaluation. Preliminary results of the predicted scatter fraction in a uniform phantom are presented.

Models, Structural↗
PubMed1991

Drug abuse prevention evaluation methodology: a bright future.

Drug abuse prevention research findings have been inconsistent. These inconsistencies can be related to several issues including study design and methodology. This article presents consensus recommendations developed to enhance drug abuse prevention evaluation research by a group of prevention researchers and practitioners who met at the National Institute on Drug Abuse in Rockville, Maryland during May 1989. As noted by the number of consensus statements, there was a high level of agreement. After exploring various aspects of evaluating prevention interventions, that agreement was reflected in specific recommendations which are directed to modifying prevention approaches; integrating epidemiologic, etiologic and intervention research methods; and expanding prevention research utilization.

Humans↗
PubMed1975

Task analysis in National Health Service Corps field stations: a methodological evaluation.

An occupational survey using a task inventory as survey instrument was conducted at four National Health Service Corps clinics providing primary ambulatory care. The prime objective of the study was to determine whether the methodology of task analysis could validly be applied to obtain data of potential value in improving personnel management in clinics. It is concluded that the taskinventory could generate such data. A first level analysis provides some interpretations of task interrelationships and role definition among clinic staff. In the clinics studied, no staff member's role was sufficiently well defined for efficient utilization of his capabilities. In particular, many tasks performed by the physicians and nurses could also be performed by less well-trained personnel. A number of steps are suggested for examining the task profiles of clinic staff and identifying areas of potential task redistribution. Also discussed are ways of improving the presentation of data obtained through task analysis to enhance the data's usefulness to local clinic management.

Community Health Services↗
PubMed1977

Evaluation methodology.

The results of several large methadone maintenance programs are reviewed and the outcome measures used are analyzed. Criteria measures were often vague and sometimes not defined. Many studies base their findings on unverified patient self-reports because costs for more reliable and systematic data collection are prohibitive. Available data does not allow for resolution of the pro- or antimethadone maintenance views for treatment of heroin addiction.

Behavior↗
PubMed1979

Adenylate cyclase cytochemistry: a methodological evaluation.

A cytochemical method for the demonstration of adenylate cyclase activity has been evaluated. Enzyme activity in the epithelium of the Müllerian part of the vaginal anlage in neonatal, oestradiol-treated mice has been studied under different experimental conditions. The effects of fixation, incubation conditions and post-fixation have been studied. Variations in the amount of impurities and acid content of the glutaraldehyde do not seem to influence the enzyme activity. High Pb2+ ion concentration seems to promote unspecific staining. Under standard conditions [2 mM Pb (NO3)2' pH 7.2, and incubation temperature 30 degrees C], neither non-enzymatic nor nonsubstrate-dependent lead trapping in the tissue could be observed. The possible contribution of other enzymes utilizing ATP and AMP-P(NH)P as the formation precipitate, has been evaluated. Both ATP and AMP-P(NH)P have been used as substrates in this study. Provided the appropriate control experiments are performed, this cytochemical method is reliable for demonstration of adenylate cyclase activity.

Adenosine Triphosphate↗
PubMed1991

Impression technique for the assessment of oedema. Technical improvement and methodological evaluation of a new technique.

A new instrument for the assessment of oedema based on the impression method is described. The measurement parameters are defined and the errors corresponding to the electrical and mechanical stability of the instrument are measured. The overall accuracy is calculated theoretically for the translocated volume. The accuracy and reproducibility are evaluated on plastic foam. The clinical procedure to measure oedema with this instrument is described. We show that the accuracy of the translocated volume parameter is very dependent on the overall stability of the instrument and that this instrument has an overall relative error of less than 7.3 per cent for a representative measurement. Experimental measurements on plastic foam show that the measurement parameters could be reproduced with standard deviations of less than 6 per cent and that the standard deviations for translocated volume are within the calculated overall relative error. Measurements on four patients with chronic oedema in an extremity show significantly different results on locations where pitting could be recognised compared to the contralateral nonoedematous extremity.

Aged↗
PubMed1986

Cerebral responses evoked by stimulation of vesico-urethral junction in man: methodological evaluation of monopolar stimulation.

Cerebral responses after bipolar stimulation (BpS) and monopolar stimulation (MpS) of the vesico-urethral junction (VUJ), as well as skin surface stimulation of various hip and pelvic structures, were recorded in 13 normal control subjects. BpS of VUJ produced cerebral evoked potentials (CEPs) with a negative peak (mean latency 88.69 +/- 13.73 msec) following a smaller positive deflection, while MpS of the same sites with indifferent electrodes placed on various pelvic or hip structures resulted in different response latencies that were all significantly shorter than those of BpS. Shape and latency of responses after MpS of VUJ were similar to those elicited by skin surface stimulation of the abdominal wall and the iliac crest; those elicited by pudendal nerve stimulation at the glans were also similar in shape but significantly greater in latency. Results strongly indicate that during MpS of VUJ the somatic or muscle afferents located in the hip and pelvic region are stimulated; consequently, BpS technique should be considered the preferred technique for investigating the physiological condition of visceral afferents arising from VUJ.

Adult↗
PubMed1976

Antibacterial susceptibility testing by the dip-slide technique: a methodological evaluation.

Antibacterial susceptibility testing of urine specimens by the dip-slide method was compared to the standardized disc diffusion method. A boarder line of 12 mm inhibition zone on the slide could be used to select strains resistant to sulphisadimidine, ampicillin, nitrofurantoin or nalidixic acid. In the case of the sulphonamide, the results were grewtly influenced by composition of the medium. Susceptibility testing with the dip-slide method seems to be a useful test to differentiate strains likely to respond to therapy from resistant strains.

Ampicillin↗
PubMed1989

[Methodologic evaluation of the relation of blood pressure and skinfold thickness: an epidemiologic approach].

The empirical evidence concerning the relationship between blood pressure and anthropometric characteristics (triceps skinfold, adiposity, and arm circumference) was assessed by means of meta-analysis. Different studies were evaluated critically for strength of design, methods and associations. It was found that the association between blood pressure and triceps skinfold holds for three different demographic categories. The question as to the independence of these associations remained unsolved. The effect of arm adiposity on the measurement of blood pressure was also discussed. Recommendations are give in order to standardize blood pressure measurements in clinical and research settings.

Adolescent↗
PubMed1992

Immunoassay of CEA, CA 19-9, CA 125, and CA 15-3 on the automated systems ES 300 and ES 600: methodological evaluation from a multicentre collaborative study.

The analytical performance of the automated Enzymun Test System ES 300 and ES 600 (developed by Boehringer Mannheim) for the assay of the tumour markers CEA, CA 19-9, CA 125, and CA 15-3, was assessed from data collected in a multicentre collaborative study in which eleven laboratories were involved. Results of the 1990 cycle of the external quality assessment (EQA) scheme for tumour markers, supported by the Italian National Research Council (CNR), were also used in this evaluation. The within-assay and between-assay precision was found to be 2.0 and 4.3 CV% for CEA, 2.9 and 6.8 CV% for CA 19-9, 3.6 and 9.4 CV% for CA 125, 2.9 and 6.0 CV% for CA 15-3. The between-lab variability of the four tumour markers on ES 300 and ES 600 systems was 9.4, 10.6, 11.9, 9.2 CV% for CEA, CA 19-9, CA 125 and CA 15-3 respectively. These values were comparable to or better than those obtained with the most precise manual kits used by laboratories participating in the 1990 EQA cycle. The agreement between the results from the Enzymun Test and those obtained using other method/kits was evaluated by assaying control samples previously circulated either in the CNR EQA or in the German EQA. The regression analysis indicates that for CEA, CA 125 and CA 15-3 assays the results produced by ES 300 and ES 600 are in good agreement with the consensus means of the EQAs; CA 19-9 results exhibit a worse correlation and are generally lower than the consensus mean. The linearity of the assays for the four tumour markers was checked by dilution tests performed by participants in the collaborative study; in all cases the dilution of the sample did not affect the values obtained.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1992

Structure-activity study and design of multidrug-resistant reversal compounds by a computer automated structure evaluation methodology.

We have studied the relation between the structure and the multidrug resistance-reversal activity of a set of diverse chemicals with the MULTICASE structure-activity program. A number of key structural features were identified as being related to multidrug resistance reversal activity. Using these key features, we identified seven new compounds predicted to have substantial activity. These were obtained and tested experimentally on a CHO/CHRC5 cell line derived from the AB1 Chinese hamster ovary line in the presence of vincristine and vinblastine. Of the seven compounds tested so far, four showed substantial reversal activity, the most potent of them exhibiting activity at par with verapamil.

Animals↗
PubMed1979

Bronchial carcinoma. IV. A methodological evaluation of the vitagram index for measurement of quality of survival.

The validity of the Carlens Vitagram Index was tested by using the result of therapy in 48 patients with bronchial carcinoma in advanced disease, 54 patients with localized disease and 34 deceased treated surgically. The Carlens Vitagram Index, which is additional and composed of six items, was correlated to a set of additive indexes including the same items but other item weights, which were chosen with non-controversial pre-specified restrictions. The lowest correlation achieved was an indicator of the lowest degree of consistency that could be attributed to the Carlens Index given. The definition of the index was operationalized so far that each item in the set of six items included in the index was regarded as valid, and it was also considered reasonable that only these six items should be included; that each item had a weight; that the index was obtained as a product (weight x item value) sum and that the pre-specified conditions were accepted. By using restrictive conditions the lowest correlation between the index giving the lowest correlation and the Carlens Index for the 48 patients with localized disease was 0.98, for the 54 patients with localized disease 0.91 and for the surgically treated ones 0.83. In addition to the total index, the average index per month was also studied and the corresponding correlations were 0.96, 0.86 and 0.81 respectively. The Carlens Index and its application per month was found to have good validity for inoperable patients and acceptable validity for surgically treated patients. The Carlens Index was shown to be robust and there is reason to believe that it lies close to the optimal index.

Adult↗
PubMed1979

Bronchial carcinoma. V. A methodological evaluation of the vitagram index for measurements of quality of survival by means of the "MaxMin" correlation method.

The validity of the Carlens Vitagram Index for measuring the quality of survival in bronchial carcinoma was further tested on the basis of the result of therapy in 48 patients with advanced disease, 54 patients with localized disease and 34 deceased patients surgically. Different approaches for index construction are discussed and the "MaxMin" correlation method, in which the highest of the lowest correlations is sought, is presented. The principal algorithms of the method are given, and the mathematical proof and the procedures are described and exemplified. By finding the "MaxMin" correlation a new index was constructed with weights of 20, 12.36, 12.36, 8.18, -6.15 and 0 points. The corresponding weights of the Carlens index are 20, 16, 12, 8, -4 and -2 points. Thus the Carlens index lies very close to the optimal index found with the "MaxMin" method. This result gives further proof that the Carlens index is valid for use in the types of bronchial carcinoma described above.

Adult↗