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PubMed2004

Line profile study with tunable diode laser spectrometers.

In this paper, we present the different theoretical line profiles, which can be used to describe a shape of molecular transitions in dilute gases: the Voigt, Galatry, Rautian and speed dependence models. We discuss their limitations and their advantages, and present for illustration different comparisons of model results with experimental data obtained with several diode laser spectrometers suitable for precise line shape measurements.

Chemistry Techniques, Analytical↗
PubMed1990

Chemometric study and analytical enzymatic methods for diagnosis of cholesterol gallstones.

The lithogenic index (IL) provides an estimate of cholesterol saturation in gallbladder bile and is of possible value for prediction of gallstone formation. A package for pattern recognition of analytical chemical data, known as "Parvus", was used to study the different values of IL obtained experimentally using common enzymic methods for cholesterol and bile salts and other analytical techniques for phospholipids. Ten patients were investigated and some interesting conclusions were drawn, both on the equivalence of various analytical methods for the determination of phospholipids and on the contribution of pattern recognition analysis to the diagnosis of gallstones.

Bile↗
PubMedDate not supplied

Measurement of surface contamination by certain antineoplastic drugs using high-performance liquid chromatography: applications in occupational hygiene investigations in hospital environments.

Within the context of continuing interest in occupational hygiene of hospitals as workplaces, the authors report the results of a preliminary study on surface contamination by certain antineoplastic drugs (ANDs), recently performed in eight cancer departments of two large general hospitals in Milan, Italy. Since reliable quantitative information on the exposure levels to individual drugs is mandatory to establish a strong interpretative framework for correctly assessing the health risks associated with manipulation of ANDs and rationally advise intervention priorities for exposure abatement, two automated analytical methods were set up using reverse-phase high-performance liquid chromatography for the measurement of contamination by 1) methotrexate (MTX) and 2) the three most important nucleoside analogue antineoplastic drugs (5-fluorouracil 5FU, Cytarabin CYA, Gemcytabin GCA) on surfaces such as those of preparation hoods and work-benches in the pharmacies of cancer wards. The methods are characterized by short analysis time (7 min) under isocratic conditions, by the use of a mobile phase with a minimal content of organic solvent and by high sensitivity, adequate to detect surface contamination in the 5-10 micrograms/m2 range. To exemplify the performance of the analytical methods in the assessment of contamination levels from the target analyte ANDs, data are reported on the contamination levels measured on various surfaces (such as on handles, floor surfaces and window panes, even far from the preparation hood). Analyte concentrations corresponding to 0.8-1.5 micrograms of 5FU were measured on telephones, 0.85-28 micrograms/m2 of CYA were measured on tables, 1.2-1150 micrograms/m2 of GCA on furniture and floors. Spillage fractions between 1-5% of the used ANDs (daily use 5FU 7-13 g; CYA 0.1-7.1 g; GCA 0.2-5 g) were measured on the disposable polythene-backed paper cover sheet of the preparation hood.

Antimetabolites, Antineoplastic↗
PubMed1998

Considerations in the determination of boron at low concentrations.

Experimental evidence now supports the nutritional essentiality of boron (B) in some biological systems, and accordingly, the need for reliable analytical B data is increasing. However, the accurate determination of B in biological materials is a formidable challenge at low concentrations (<1 mg B/kg). Recent studies still show significant analytical discrepancies in the analysis of animal tissues and fluids, despite the development of instrumental techniques such as TIMS, ICP-MS, ICP-ES, ICAP, SIMS, NA-MS, PGAA, NRA, and so forth, which have demonstrated detection limits approaching or exceeding (microg B/kg concentrations. Since boric acid is both volatile and ubiquitous in nature, the chemical and physical pathways for B contamination and its loss are manifold, especially during sample preparation. An added obstacle is the inadequacy of biological reference materials certified for B below mg B/kg. With an emphasis toward sample preparation and ICP-MS analysis, examples are provided in this article to help the analyst avoid common problems associated with the analysis of B from biological sources. Topics that are discussed include contamination from Teflon vessels during microwave digestion, losses owing to freeze-drying, B isotopic variations, standards preparation, reagent backgrounds, and instrumental interferences.

Animals↗
PubMed2003

[Equality as Yusho diagnosis indices between blood PCB constitution data from using a conventional analytical method and a PCB isomer specific analytical method].

This paper reports that we can replace a conventional PCB analytical method with an isomer specific analytical method in Yusho diagnosis. The authors analysed 109 blood samples from people who had the 2002 annual inspection for Kanemi rice oil poisoning using both methods. The data from these methods were compared and proved to be almost the same in the so-called "PCB pattern" which has been adopted as a Yusho diagnosis index since early 1970s.

Biomarkers↗
PubMedDate not supplied

[Effect of flying on the health status of pilots in the light of epidemiologic data].

This paper gives an analytical review of epidemiological data about the morbidity and mortality rate of the flying personnel. It shows that the flying personnel differs from the general population in their better health condition which manifests as lower morbidity and mortality rates in every large group of disease. This better health status of the flying personnel may be a result of their adequate selection. The selection makes it difficult to identify relationships between disease and flight effects. Information about these relationships is contradictory and/or insufficient. Proper assessment of flight effects on the health condition of the flying personnel needs further controlled epidemiological investigations.

Accidents, Occupational↗
PubMed1981

A mathematical model for the analysis of the turnover of protein mixtures. III. Practical problems in the investigation of heterogeneous protein pools.

In part 1 of this series [1] a model was presented fo the turnover of a protein pool consisting of proteins with different turnover constants which can be described mathematically by a set of integro-differential equations. As in the general case this system is not treatable analytically, a computer programme was developed to solve it numerically. The applicability of the programme and, more generally, of the model was tested using computer generated and real data. The analytical solutions of special cases (tracer elimination after pulse labeling and continuous labelling) which form modified power functions were given in part 2 [2]. on the basis of these functions problems of the design of experiments for a quantitative analysis of pool heterogeneities are discussed. In both cases a duration of the experiment of at least two or three times the reciprocal mean turnover constant turns out to be necessary; a combination of the two procedures is more appropriate. On the other hand, it is shown that after continuous labelling heterogeneity can largely be neglected. But with the experimental design f pulse labelling which is often used heterogeneity must always be taken into account even if it is not the direct object of the investigation since otherwise the calculated turnover constant is an error (too high by factor of about 2).

Computers↗
PubMed2004

Data quality affects meta-analytic conclusions: a response to Miner and Raju (2004) concerning entrepreneurial risk propensity.

J. B. Miner and N. S. Raju (2004) contended that there are additional studies that compare the risk propensity of entrepreneurs and managers, which, when added to the data from W. H. Stewart and P. L. Roth (2001) and meta-analyzed, produce relationships between risk propensity and entrepreneurial status that are substantially weaker than previously believed. This conclusion was evaluated by identifying and examining methodological problems associated with their inclusion of effect sizes (i.e., ds) from studies with variables not relevant to research questions, dependent samples, extraneous variance in outcome variables, and confusion of constructs. When these methodological issues were addressed, a new meta-analysis indicated an overall conclusion consistent with that of Stewart and Roth, but the results varied according to instrumentation, particularly objective instrumentation (observed d = 0.31) versus the Miner Sentence Completion Scale-Form T (observed d = -0.35).

Entrepreneurship↗
PubMed1980

Factor analytic study of the personality of female methadone outpatients.

Several researchers have examined the personality of chemical abusers by employing a multivariate clustering strategy. All of these studies focused on hospitalized inpatient addicts. Only one included females in the study. The purpose of this study is to examine the transposed data factor analytically derived profiles of female methadone maintained outpatients. All clients were given the Mini-Mult short form version of the Minnesota Multiphasic Personality Inventory. Seventy profiles were randomly selected from 130 female profiles. Program Factor of the Analyses of Behavioral Sciences Data program series was employed in statistically processing this data. Descriptions of the five factors are provided. Most of the profile types seem to fall into the normal or personality disordered categories. Forth-two percent of the profiles were normal, 24% were Personality Disorders, 6% were Neurotic, and 28% were unclassified using five factors.

Adult↗
PubMedDate not supplied

Ethyl carbamate: analytical methodology, occurrence, formation, biological activity and risk assessment.

Ethyl carbamate (EC) is a genotoxic compound in vitro and in vivo, it binds covalently to DNA and is an animal carcinogen. Today, EC is mainly found as a natural trace constituent in different alcoholic beverages and in fermented food items. Data on analytical methodology and the levels of EC in different food items are summarized and the daily burden of humans is estimated. Under normal dietary habits excluding alcoholic beverages, the unavoidable daily intake is 10-20 ng/kg b.w. On the basis of the evaluation of all toxicity data and its mode of action a conventional risk assessment of EC indicates that this level represents a negligible lifetime cancer risk (less than 0.0001%). Individual habits may greatly enhance the risk. Regular drinking of table wine (500 ml/day) would increase the risk up to 5 times, regular drinking of stone-fruit distillates (20-40 ml/day) would raise the calculated hypothetical tumor risk to near 0.01%. Human exposure to carcinogenic compounds should be as low as reasonably achievable. In order to take reliable measures to reduce EC levels in beverages and foods, it is crucial to know the mode of its formation. For its natural formation the presence of ethanol is absolutely required. In stone-fruit distillates hydrogen cyanide together with photochemically active substances are crucial to form EC. The main part of EC is formed after the distillation involving photochemical reactions. In wine (and probably bread) significant EC formation seems to depend on heat treatment. While in distillates hydrogen cyanide is the most important single precursor, in wine different carbamyl compounds, mainly urea, seem to be involved in EC formation. Despite this apparent difference a common EC formation pathway is discussed for all alcoholic beverages by assuming cyanic-/isocyanic acid as an important ultimate reactant with ethanol. Some ideas are presented as to the possible course of future work.

Carcinogens↗
PubMed2005

The bottom-up solution to the triacylglycerol lipidome using atmospheric pressure chemical ionization mass spectrometry.

Presented here is an approach to representing the data from atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) of triacylglycerols (TAG) using a set of one, two, or three Critical Ratios. These Critical Ratios may be used directly to provide structural information concerning the regioisomeric composition of the triacylglycerols (TAG), and about the degree of unsaturation in the TAG. An AAA-type, or Type I, TAG has only one Critical Ratio, the ratio of the protonated molecule, [M + H]+, to the DAG fragment ion, [AA]+. The Critical Ratio for a Type I TAG is [MH]+/Z[DAG]+, and the mass spectrum of a Type I TAG can be reproduced from only this one ratio. An ABA/AAB/BAA, or Type II, TAG has two Critical Ratios, the [MH]+/sigma[DAG]+ ratio and the [AA]+/[AB]+ ratio. The [AA]+/[AB]+ ratio for a single TAG or TAG mixture can be compared with the [AA]+/[AB]+ ratios of pure regioisomeric standards, and the percentage of each regioisomer can be estimated. The abundance of the protonated molecule and the abundances of the two [DAG]+ fragment ions can be calculated from the two Critical Ratios for a Type II TAG. To calculate the abundances, the Critical Ratios are processed through the Bottom-Up Solution to the TAG lipidome. First, Critical Limits are calculated from the Critical Ratios, and then the Critical Ratios are classified into Cases by comparison with the Critical Limits. Once the Case classification is known, the equation for the abundance of each ion in the mass spectrum is given by the Bottom-Up Solution. A Type III TAG has three different FA and three Critical Ratios. The [MH]+/Z[DAG]+ ratio is the first Critical Ratio, the [AC]+/([AB]+ + [BC]+) ratio is the second Critical Ratio, and the [BC]+/[AB]+ ratio is the third Critical Ratio. The second critical ratio for a Type III TAG can be compared with regioisomeric standards to provide an estimate of the percentage composition of the regioisomers. The three Critical Ratios for a Type III TAG can be processed through the Bottom-Up Solution to calculate the four ion abundances that make up the APCI-MS mass spectrum. The Critical Ratios constitute a reduced data set that provides more information in fewer values than the raw abundances.

Atmospheric Pressure↗
PubMed2003

A demonstration of interval-censored survival analysis.

Interval-censoring occurs in survival analysis when the time until an event of interest is not known precisely (and instead, only is known to fall into a particular interval). Such censoring commonly is produced when periodic assessments (usually clinical or laboratory examinations) are used to assess if the event has occurred. My objectives were to raise awareness about interval-censoring including its existence, the potential ramifications of ignoring its existence, the different types of interval-censored data, and the analytical methods to analyze such data (including availability in standard statistical software). Asynchronous interval-censored survival analysis was demonstrated by parametric evaluation of risk factors for the time to first detected shedding of Salmonella muenster (identified by repeated periodic fecal cultures) for a herd of dairy cows. These results were compared with those from survival analyses which ignored or approximated the interval-censoring. Ignoring or approximating the asynchronous interval-censoring in the survival analysis generally resulted in the risk factors' regression coefficients having the same signs and a decrease (often >50%) in their absolute size. All the standard errors from the three methods of approximating the interval-censoring were <40% of their interval-censored counterparts. The conclusions drawn from the asynchronous interval-censored analysis versus those from the approximations varied dramatically. (The general conclusion from the approximations was that none of the risk factors for this example warranted further consideration.) That ignoring or approximating the left- and interval-censored nature of the dependent variable resulted in biased results was consistent with the literature. In the currently available asynchronous interval-censored models, the inclusion of time-dependent covariates that vary continuously is awkward. Statistical models for the semi-parametric estimation of asynchronous interval-censored survival analysis are not generally available in standard statistical software.

Animals↗
PubMed2003

Developing evidence-based clinical indicators: a state of the art methods primer.

OBJECTIVE: To describe steps in developing and testing clinical indicators based on state of the art methods in previous literature and experience in the Danish National Indicator Project. ANALYSIS: The development process includes a planning phase, where the clinical area to be evaluated is chosen and the measurement team selected and organized. The planning phase is followed by a development phase where clinical indicators are prioritized and selected by the measurement team on the basis of documentation and knowledge from the scientific literature. When clinical indicators have been selected, specific measure specifications should be designed, including inclusion and exclusion criteria for the target population, description of a risk adjustment strategy, identification of data sources, description of data collection procedures, and an analytical plan for data analyses. Before clinical indicators are implemented they should be tested for reliability and validity. Preliminary tests may identify areas requiring further modifications and specifications of the indicators. CONCLUSION: Using clinical indicators for quality assessment represents an important approach to documenting the quality of care. Consumers of indicator information (clinicians, administrators, purchasers, regulators, and patients) need reliable and valid information for benchmarking, making judgments, and determining priorities, accountability and quality improvement. This underlines the fact that clinical indicators must be developed and tested with scientific rigor in a transparent process.

Benchmarking↗
PubMed1984

[The lung in peritonitis. Contribution of data processing to the evaluation of pulmonary risk: practical conclusions].

A retrospective study of 99 case-reports of patients with generalized peritonitis, including 38 postoperative cases involving peritoneum and lungs, was conducted with the aid of two files based on documented data containing 168 and 204 analytical criteria respectively. Data processing and statistical analysis alone were capable of establishing possible relationships between isolated or associated peritoneal factors and respiratory manifestations. Out of the vast quantity of data obtained by using this new approach, only factors significantly affecting pulmonary complications were retained: some relations could not be established because of the small number of patients studied. Respiratory complications were frequent (60%) and severe (58% mortality). They occurred in 96% of postoperative peritonitis cases, with 77% of deaths, and in 44% of primary peritonitis cases, with 36% of deaths. In contrast, when absent the mortality is reduced to 4%. Frequency distribution of clinical signs, pulmonary radiological images and the effects of gasometry are analyzed. Obstruction is a frequent and early symptom. The presence of bilateral diffuse lung shadows and their shunt effect are narrowly correlated with the presence of postoperative peritonitis. Respiratory complications were correlated with peritonitis criteria, particularly with age, the sub-mesocolon origin of the peritonitis, the rapidity of operative intervention, and surgical excision rather than shunt formation or suturing, and to the development of criteria of repeat abdominal or extra-abdominal surgery. Initial antibiotherapy and digestive suction have, on the contrary, no effect. Many other criteria were studied. A "profit" of patients liable to develop these complication is described, the mechanisms outlined, and the means of prevention and of rapid detection discussed, particularly the important role played by early gasometry.

Bacterial Infections↗
PubMed2004

Interpersonal problems and outcome in outpatient psychotherapy: findings from a long-term longitudinal study in Germany.

We used a comprehensive longitudinal data set from Germany to examine trajectories of symptom distress depending on interpersonal problems at study intake measured via the Inventory of Interpersonal Problems-64 (IIP-64; Horowitz, Strau, & Kordy, 1994). Participants (N=622) underwent mid- or long-term outpatient psychotherapy (either psychodynamically oriented psychotherapy, cognitive behavioral therapy, or analytic psychotherapy). Data comprises up to 5 assessments during a 2-year period and was analyzed via hierarchical linear modeling. In the analytic psychotherapy subgroup, initial symptom level was higher in submissive patients. Initial interpersonal problems were not predictive of the rate of symptom change during therapy. Only in psychodynamic treatments, low affiliation positively affected treatment outcome. Interpersonal problems at intake were not related to the number of utilized sessions and utilization rate across treatment subgroups. We discuss the findings and outline future research topics.

Adult↗
PubMedDate not supplied

[General criteria for the development and use of data tables and systems on food composition].

The growing interest in the field of community nutrition and nutritional quality has originated a major demand on food composition information. This has made an increase in the number of food composition tables as well as in its applications. However, often the appropriate interpretation of the information obtained is misused. Food composition tables need to be considered as data systems, not only restricted to the tabulated information, that try to compile composition of most important representative food in the region. Difficulties arising from this method at different levels (sampling, analytical procedures, data presentation, etc.) make to the researcher the need to consider several risks. On the other hand, the application of food composition tables is subjected to many sources of variability. The present work tries to make clear the main considerations in using food composition tables appropriately, as well as in managing software and interpreting results from food consumption studies.

Computer Systems↗
PubMed1993

The detection of problem analytes in a single proficiency test challenge in the absence of the Health Care Financing Administration rule violations.

The Clinical Laboratory Improvement Act of 1988 (CLIA 88) has dramatically changed proficiency testing (PT) practices having mandated (1) satisfactory PT for certain analytes as a condition of laboratory operation, (2) fixed PT limits for many of these "regulated" analytes, and (3) an increased number of PT specimens (n = 5) for each testing cycle. For many of these analytes, the fixed limits are much broader than the previously employed Standard Deviation Index (SDI) criteria. Paradoxically, there may be less incentive to identify and evaluate analytically significant outliers to improve the analytical process. Previously described "control rules" to evaluate these PT results are unworkable as they consider only two or three results. We used Monte Carlo simulations of Kodak Ektachem analyzers participating in PT to determine optimal control rules for the identification of PT results that are inconsistent with those from other laboratories using the same methods. The analysis of three representative analytes, potassium, creatine kinase, and iron was simulated with varying intrainstrument and interinstrument standard deviations (si and sg, respectively) obtained from the College of American Pathologists (Northfield, Ill) Quality Assurance Services data and Proficiency Test data, respectively. Analytical errors were simulated in each of the analytes and evaluated in terms of multiples of the interlaboratory SDI. Simple control rules for detecting systematic and random error were evaluated with power function graphs, graphs of probability of error detected vs magnitude of error. Based on the simulation results, we recommend screening all analytes for the occurrence of two or more observations exceeding the same +/- 1 SDI limit. For any analyte satisfying this condition, the mean of the observations should be calculated. For analytes with sg/si ratios between 1.0 and 1.5, a significant systematic error is signaled by the mean exceeding 1.0 SDI. Significant random error is signaled by one observation exceeding the +/- 3-SDI limit or the range of the observations exceeding 4 SDIs. For analytes with higher sg/si, significant systematic or random error is signaled by violation of the screening rule (having at least two observations exceeding the same +/- 1 SDI limit). Random error can also be signaled by one observation exceeding the +/- 1.5-SDI limit or the range of the observations exceeding 3 SDIs. We present a practical approach to the workup of apparent PT errors.

Bias↗
PubMed1993

Pre-analytical, analytical and biological sources of variation of lipoprotein(a).

The pre-analytical, analytical and biological sources of variation were estimated for serum lipoprotein(a) concentrations, as measured with a new commercially available procedure. There were no significant differences between the concentrations of lipoprotein(a) measured in EDTA plasma and serum. The analyte is stable in specimens stored for up to two weeks in the refrigerator, or up to three months at-20 degrees C. Fasting is not essential before the lipoprotein(a) determination. Data on analytical (between-run coefficient of variation < 15.7%), within-subject (8.6%) and between-subject variation (85.8%) were used to calculate the analytical goal for imprecision (< 4.3%), the critical difference between serial values from an individual that represents a significant change (36.3%), the number of specimens which should be collected to estimate the homeostatic value for an individual to within +/- 5% (26), and to establish the marked individuality of lipoprotein(a) (index of individuality, 0.1).

Adult↗