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PubMed1991

Chiral drugs: an industrial analytical perspective.

In the pharmaceutical industry, chiral drug candidates introduce a unique set of challenges to all disciplines involved in the drug development process. For the analytical chemist in particular, the generation of relevant information about a variety of stereoisomeric issues is necessary. Chiral drug candidates, whether a single isomer or a mixture of isomers, require more analytical information than achiral drug candidates. This information can be derived from enantioselective spectroscopic and chromatographic techniques. Chiral analytical methods require proper development and validation to ensure accurate results. Issues related to method development and validation for complete stereochemical characterization are discussed, with primary emphasis on the generation of analytical data required for the registration of a chiral drug candidate. The presentation of pertinent analytical data depends on an awareness of the problems encountered during the development process and the appropriate use of methodology for the determination of stereoisomeric purity.

Animals↗
PubMed1998

Quality assurance in veterinary diagnostic laboratories.

The authors discuss the responsibility of veterinary diagnostic laboratories as suppliers of analytical data for tests on animals and animal products. The guarantee of the quality of analytical data is a basic quality requirement for veterinary certification. It is therefore important for the laboratory to adopt operational quality assurance standards which are recognised internationally. The management and quality assurance criteria contained in the International Standardisation Organisation/International Electrotechnical Commission Guide 25, or in directives or guidelines established by international organisations such as the Office International des Epizooties and the Codex Alimentarius of the Food and Agriculture Organisation, are reviewed. These documents provide procedures for adopting the principles of quality assurance in order to acquire the recognition of competence to execute the laboratory tests required for national and international veterinary certification.

Animals↗
PubMed1985

Toxicity modeling and prediction with pattern recognition.

Empirical models can be constructed relating the change in toxicity to the change in chemical structure for series of similar compounds or mixtures. The first step is to translate the variation in structure to quantitative numbers. This gives a data table, a data matrix denoted by X, which then is analyzed. The same type of the models can be used to relate the variation of in vivo data to the variation of a battery of in vitro tests. A single data analytical model cannot be applied to a set of compounds of diverse chemical structure. For such data sets, separate models must be developed for each subgroup of compounds. The data analytical problem then partly is one of classification, pattern recognition (PARC). The assumption of structural and biological similarity within each subset of modeled compounds is then essential for empirical models to apply. PARC is often used to classify compounds as active (toxic) or inactive. The data structure is then often asymmetric which puts special demands on the data analysis, making the traditional PARC methods inapplicable. Depending on the desired information from the data analysis and on the type of available data, four levels of PARC can be distinguished: (I) the data X are used to develop rules for classifying future compounds into one of the classes represented in X; (II) same as I, but the possibility of future compounds belonging to "unknown" classes not represented in X is taken into account; (III) same as II, plus the quantitative prediction of one activity variable (here toxicity) in some classes; (IV) same as III, but several quantitative activity (toxicity) variables are predicted.

Mathematics↗
PubMed1991

Integrated approach for designing medical decision support systems with knowledge extracted from clinical databases by statistical methods.

In clinical research data is often studied by a particular method without previous analysis of quality or semantic contents which could link clinical database and data analytical (e.g. statistical) procedures. In order to avoid bias caused by this situation, we propose that the analysis of medical data should be divided into two main steps. In the first one we concentrate on conducting the quality, semantic and structure analyses. In the second step our aim is to build an appropriate dictionary of data analysis methods for further knowledge extraction. Methods like robust statistical techniques, procedures for mixed continuous and discrete data, fuzzy linguistic approach, machine learning and neural networks can be included. The results may be evaluated both using test samples and applying other relevant data-analytical techniques to the particular problem under the study.

Artificial Intelligence↗
PubMed1990

Psychotherapy process research: progress, dilemmas, and future directions.

The first several decades of psychotherapy process research have produced advances in measure development and substantive findings of process-outcome relations. A recent paradigm shift toward sequentially patterned, significant change episodes is described, emphasizing segmentation of process by meaningful patterns wherever they occur. Theoretical, psychometric, and data analytic dilemma are reviewed. Strategies are offered that may enhance future research efforts. These include greater attention to construct validity of measures, the relation of process to phase-specific outcome criteria, and the continuing development of multivariate data analytic strategies that take into account Patient X Treatment interactions as well as the sequential dependency of process data. The development of a national archive of significant change events is recommended to advance modeling of the change process, segmentation, construct validation of measures, integration of qualitative and quantitative approaches, and development of a cross-theoretical language for therapy process.

Follow-Up Studies↗
PubMed1993

Analytical and biological data of banked samples--a requirement to interpret accumulation and leaching of pollutants in biological specimens.

The accumulation of organic and inorganic pollutants in biological specimens depends, in many cases, not only on the atmospheric deposition or immission and contamination of the biotop, but also on the dynamic properties of the indicator. Thus the analytical data assume properties of process variables. In order to compare them in relation to space and time, it is often practical to refer them to defined conditions of the indicator (stationary phases, time cycles of low dynamics). If the accumulation varies consistently under identical conditions of contamination and if clear functional relations exist to the features of the indicator, for instance age, weight or ecological processes, it is necessary to normalize the analytical data, i.e. to refer them to a condition of the indicator which is defined meaningfully with regard to the ecology. Interactions with other inputs of substances may result in a differentiation of accumulation and leaching processes which is more or less specific for each element. Such knowledge is important for specifying the standard operation procedures and the evaluation as well as interpretation of analytic data, in particular, in the clarification of the ecotoxicological relations between the pollutant accumulation and the reaction of populations and ecosystems.

Animals↗
PubMed2002

Recent developments in food characterization and adulteration detection: technique-oriented perspectives.

This review covers mainly publications that appeared in Analytical Abstracts (Royal Society of Chemistry) from January 1990 to February 2001. The number of publications on this topic continues to grow, and during the past three years (1998-2000) about 150 reviews and/or overviews have been published in the area of food. Numerous techniques and food matrices or chemical components are presented and discussed in these reviews. The present review is intentionally limited to eight techniques or classes of techniques and intends to be a "technique by technique" presentation of "what was used" or "what is used" to characterize food products and to detect their possible adulteration. The present review focuses on the following techniques: microscopic analysis; HPLC; GC, GC-(MS, FTIR); UV-visible spectrophotometry; AAS/AES, ICP-(AES, MS); IRMS, GC-IRMS, GC-C-IRMS; DSC; IR, mid-IR, and NMR (202 references). Emphasis is placed as much as possible on chemometrical treatment of analytical data, which are commonly used to achieve the final objective, either food characterization or adulteration detection. Finally, a brief description is given of the new generation of analytical systems that combine powerful analytical techniques and powerful computer software for a best extraction of the information from analytical data.

Calorimetry, Differential Scanning↗
PubMed2000

Estimation of structural wave numbers from spatially sparse response measurements.

A method is presented for estimating the complex wave numbers and amplitudes of waves that propagate in damped structures, such as beams, plates, and shells. The analytical basis of the method is a wave field that approximates response measurements in an aperture where no excitations are applied. At each frequency, the method iteratively adjusts wave numbers to best approximate response measurements, using wave numbers at neighboring frequencies as initial estimates in the search. In comparison to existing methods, the method generally requires far fewer measurement locations and does not require evenly spaced locations. The number of locations required by the method scales with the number of waves that propagate in the structure, whereas the number of locations required by existing methods scales with the minimum wavelength. In addition, the method allows convenient inclusion of the analytic relationships between wave numbers that exist for flexural vibrations of beams and plates. Advantages of the method are illustrated by an example in which a beam is excited by a transverse force at one end. Using analytic data and experimental measurements, the method produces a wave field that matches response measurements to within 1 percent. One interesting feature of the new method is that, when applied to analytic data, it supplies more robust wave number estimates using responses at unevenly spaced locations.

Acoustics↗
PubMed2001

Measurement of near zero concentration: recording and reporting results that fall close to or below the detection limit.

Issues relating to the recording and reporting of analytical data obtained where the concentration of analyte is around or below the detection limit are discussed. The following recommendations are proposed. Analytical results should be recorded by the analyst exactly as they occur, including any negative results, and such records retained for an appropriate length of time. For the purposes of quality assurance in the laboratory (including method validation, internal quality control, and proficiency testing), negative results should be used as they stand. Analytical results reported to a customer should be accompanied by a statement of uncertainty including, in the present context, uncertainty at low concentrations of analyte. The method of editing of reported results must be a contractual matter between the analyst and the customer, but a statement of the procedure used should accompany the results and should be explicit. Normally such editing should be restricted to setting negative results to zero. The customer should be encouraged to pass on the statement to all end users. Data intended for the public domain should be accompanied by a statement detailing the uncertainty, the method of editing, and the location of the unedited data. Most types of statistical processing of datasets containing low concentrations of analyte should be undertaken on the unedited data.

Journal Article↗
PubMed2002

Nonparametric discriminant analysis of phytoplankton species using data from analytical flow cytometry.

BACKGROUND: Analytical flow cytometry (AFC) provides rapid and accurate measurement of particles from heterogeneous populations. AFC has been used to classify and identify phytoplankton species, but most methods of discriminant analysis of resulting data have depended on normality assumptions and outcomes have been disappointing. METHODS AND RESULTS: In this study, we consider nonparametric methods based on density estimation. In addition to the familiar kernel method, methods based on wavelets are also implemented. Full five-dimensional wavelet estimation proves to be computationally prohibitive with current workstation power, so we employ projection pursuit for reduction of dimensionality. AFC typically produces very large samples, so we also investigate data simplification through binning. Further modifications to the discrimination strategy are suggested by specific features of phytoplankton data, namely, a hierarchical group structure, the possible presence of many groups, and the likelihood of encountering an aberrant group in a test sample. CONCLUSIONS: We apply all the resultant procedures to appropriate subsets of a very large data set, demonstrate their efficacy, and compare their error rates with those of more conventional methods. We further show that incorporation of the specific features of phytoplankton data into the analysis leads to improved results and provides a general framework for analysis of such data.

Animals↗
PubMedDate not supplied

[Complementary artificial nutrition in kidney failure].

Denutrition of the uremic patient is a substantial contributing factor to the high rate of morbimortality. At the present time there are no resources which slow the catabolic situation conditioned by humoral or hormonal factors, but resources are available which act on the nutritional factors. The aim of this paper is to study the effect of additional administration of a complete enteral diet, but high in calories and in proteins, on the nutrition of dialysis patients. Six patients undergoing periodic hemodialysis and without metabolic illness were selected: 236 ml of the solution was administered orally on a daily basis for two months. They were studied statistically using the SIGMA Program, with application of the comparison of paired averages, the variations of anthropometric and analytical data and urea kinetics. The results revealed a significant body weight increase, from 58 to 60 kg, and of the tricipital fold from 10 to 12 cm: both variations were statistically significant (p < 0.01). There were no variations in the analytical data, or in the urea kinetics (the PCR was 0.8 g/kg/day and the Kt/V was 0.8). It is concluded that it significantly improves the nutritional state, there are no side effects and it does not detract from the efficacy of the dialysis. Therefore, and although the indication for which it was designed was for predialysis patients, we think that those under periodic hemodialysis--and, form the same reasons, acute kidney failure patients--might be areas for the use of this product.

Adult↗
PubMedDate not supplied

[Shwachman's syndrome].

BACKGROUND: Shwachman syndrome has been recognized as the second most frequent cause of pancreatic insufficiency in children and its is related to hematological and bony abnormalities. AIMS: To know the main clinical symptoms, analytical data, radiological and sonographic findings in the Shwachman syndrome. MATERIALS AND METHODS: We present a 1 year 4 months old girl with Shwachman syndrome. We reviewed the clinical history taking into consideration height/weight relationship according to percentiles and physical examination. Analytical data: blood counts, fetal hemoglobin, vitamin B12 and folate levels, bone marrow examination, stool cultures and examination for ova and parasites, transaminase levels, sweat electrolytes, serologic tests for viral hepatitis. Radiological studies: bone series and bone age, abdominal sonography and computed tomography. Liver and intestinal biopsies. RESULTS: In this patient we confirmed the presence of exocrine pancreatic insufficiency, dysfunction of the bone marrow and bony abnormalities typical in Shwachman syndrome.

Bone and Bones↗
PubMed1982

Twin transference as a compromise formation.

This paper explores the meanings and functions of a transference paradigm of a fantasied twin relationship with the analyst. Twin transference in the analysis of nontwins has been reported infrequently in the psychoanalytic literature, except recently by Kohut and his co-workers, who refer to twinship transference as a variant of narcissistic mirror transference. We suggest that such narrow definition tends to reduce the complexity of the wish for a twinlike relationship with the analyst. Analytic data are used to show the advantages of examining twin transference within structural theory, in terms of the multiple functions served by this rather primitive transference paradigm, rather than reducing it only to one variant of the need for certain mirroring functions. We suggest that twin transference, together with all twin fantasies, subserves multiple functions, of which we highlight gratification and defense against the dangers of intense object need. In this formulation, the twinlike representation of the object provides the illusion of influence or control over the object by the pretense of being able to impersonate or transform oneself into the object and the object into the self. Intense object need persists together with a partial narcissistic defense against full acknowledgment of the object by representing the sought-after object as combining aspects of self and other. Further analytic attention needs to be directed to the specific representation of the needed object in certain primitive transference paradigms instead of exclusive emphasis on the functions required of the object. Our analytic data are used to argue that intense early needs of an object are best understood analytically within a conflict model in which they are modified by multiple wishes, drives, fears, dangers, and needs for defense.

Dreams↗
PubMed1998

Relation between diffuse axonal injury and internal head structures on blunt impact.

Diffuse axonal injury (DAI) is a severe head injury, which exhibits symptoms of consciousness disturbance and is thought to occur through rotational angular acceleration. This paper analyzes the occurrence of DAI when direct impacts with translational accelerations are applied to two-dimensional head models. We constructed a human model reproducing the human head structure, as well as modified human models with some internal head structures removed. Blunt direct impacts were applied from a lateral direction to the bottom of the third ventricle, considered to be the center of impact, using an impactor. The analysis was done by comparing the macroscopic manifestation of DAI with the shear stress as the engineering index. In the analytical data obtained from the human model, shear stresses were concentrated on the corpus callosum and the brain stem, in the deep area. This agrees with regions of the DAI indicated by small hemorrhages in the corpus callosum and the brain stem. The analytical data obtained by the modified human models show that the high shear stress on the corpus callosum is influenced by the falx cerebri, while the high shear stress on the brain stem is influenced by the tentorium cerebelli and the shape of the brain. These results indicate that DAI, generally considered to be influenced by angular acceleration, may also occur through direct impact with translational acceleration. We deduced that the injury mechanism of DAI is related to the concentration of shear stress on the core of the brain, since the internal head structures influence the impact stress concentration.

Acceleration↗
PubMedDate not supplied

The stone decay of monuments in relation to atmospheric environment.

In order to explain why different forms of decay are present on a building facade some samples were taken from different areas of many monuments. Macroscopic observations of the forms of decay were correlated with quantitative analytical data in order to build up a simple model which was able to explain in a general way the decay phenomena. This simplified model was tested on several Venetian monuments and the features visible on stone surfaces correspond to different degree of deterioration. The quantitative analytical data were associated with the different forms of decay, which were defined as white washing, dirt accumulation and dirt washing. The results obtained showed that the features visible on stone surfaces corresponded to different degree of deterioration and the sulphate formation is greatest in the black dendrite-shaped crusts which are generally formed at the interface between the white washing areas and the sheltered ones, which were defined as dirt washing area.

Air Pollutants↗
PubMed1982

Hair analyses: worthless for vitamins, limited for minerals.

Despite many major and minor problems with interpretation of analytical data, chemical analyses of human hair have some potential value. Extensive research will be necessary to define this value, including correlation of hair concentrations of specific elements with those in other tissues and metabolic pools and definition of normal physiological concentration ranges. Many factors that may compromise the correct interpretation of analytical data require detailed evaluation for each specific element. Meanwhile, hair analyses are of some value in the comparison of different populations and, for example, in public health community surveys of environmental exposure to heavy metals. On an individual basis, their established usefulness is much more restricted and the limitations are especially notable for evaluation of mineral nutritional status. There is a wide gulf between the limited and mainly tentative scientific justification for their use on an individual basis and the current exploitation of multielement chemical analyses of human hair.

Adult↗
PubMed1976

Doping control in Japan. An automated extraction procedure for the doping test.

Horse racing in Japan consists of two systems, the National (10 racecourses) and the Regional public racing (32 racecourses) having about 2,500 racing meetings in total per year. Urine or saliva samples for dope testing are collected by the officials from thw winner, second and third, and transported to the laboratory in a frozen state. In 1975, 76, 117 samples were analyzed by this laboratory. The laboratory provides the following four methods of analysis, which are variously combined by request. (1) Method for detection of drugs extracted by chloroform from alkalinized sample. (2) Methods for detection of camphor and its derivatives. (3) Method for detection of barbiturates. (4) Method for detection of ethanol. These methods consist of screening, mainly by thin layer chromatography and confirmatory tests using ultra violet spectrophotometry, gas chromatography and mass spectrometry combined with gas chromatography. In the screening test of doping drugs, alkalinized samples are extracted with chloroform. In order to automate the extraction procedure, the authors contrived a new automatic extractor. They also devised a means of pH adjustment of horse urine by using buffer solution and an efficient mechanism of evaporation of organic solvent. Analytical data obtained by the automatic extractor are presented in this paper. In 1972, we started research work to automate the extraction procedure in method (1) above, and the Automatic Extractor has been in use in routine work since last July. One hundred and twnety samples per hour are extracted automatically by three automatic extractors. The analytical data using this apparatus is presented below.

Animals↗
PubMed1997

Factors that influence effect size in 15O PET studies: a meta-analytic review.

The PET literature is growing exponentially, creating a need and an opportunity to perform a meta-analytic review consolidating the published information. This study describes the use of effect size as an index in PET studies and discusses how this measure can be used for comparing findings across studies, laboratories, and paradigms. In comparing studies across laboratories it is essential to know how the methods employed affect the results and conclusions drawn. This study also compared effect size for two different methods of tracer delivery in 15O PET studies ([15O]H2O bolus injection versus inhalation of [15O]CO2), whether averaged versus single-scan conditions were used, and the data analytic strategy employed. The effect sizes observed across studies were consistently large with a median effect size of 8.55, indicating that the phenomena investigated in 15O PET studies are strong. The largest peak activation reported in a study was found to be affected by variability in sample size, data analytic strategy, and repeat versus single-scan conditions. However, the impact of these factors was not examined on smaller or less intense peaks. Minimal standards for reporting statistical results are discussed.

Data Interpretation, Statistical↗