Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Analytical Approach”

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

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

At least 451 records · Page 25Linked to original sources
PubMed2002

[The background of acid-base interactions in nonaqueous solvents--an analytical approach].

The acid-base determination of different substances by non-aqueous titrations is highly preferred in pharmaceutical analyses since the method is quantitative, exact and well reproducible. The modern interpretation of the reactions in nonaqueous solvents started in the past century, but several inconsistencies and unsolved problems can still be found in the literature. The acid-base theories of Brönsted-Lowry and Lewis as well as the so-called solvent theory are outlined first, then the promoting (and levelling) and the differentiating effects are discussed on the basis of the hydrogen bond concept.

Acid-Base Equilibrium↗
PubMed2005

Estimating the diagnostic accuracy of procalcitonin as a marker of the severity of acute pancreatitis: a meta-analytic approach.

CONTEXT: Approximately 15-20% of cases of acute pancreatitis are categorized as severe. There is a lack of accurate predictors of disease severity. Several studies have evaluated the usefulness of procalcitonin as a marker of severe disease. Reports regarding the diagnostic accuracy of procalcitonin are conflicting. OBJECTIVE: The present meta-analysis was carried out to evaluate the relevance of procalcitonin as a predictor of disease severity. METHODS: Two investigators working independently attempted to locate eligible studies by electronic and manual means. Studies in which at least one of the markers of disease severity was procalcitonin were included for analysis. For all the studies included, the following parameters were calculated: true positive, false negative, false positive and true negative. A summary receiver operating characteristic (SROC) curve was generated from these parameters. RESULTS: Four studies were finally included in the analysis. The unweighted regression line parameters b and i were 3.633 and 1.399, respectively. The values for b and i for weighted regression line were 3.637 and 1.428. The SROC curve generated demonstrated that procalcitonin is not a good predictor of the severity of acute pancreatitis. CONCLUSION: The available data indicates that procalcitonin cannot be considered a good marker for assessing the severity of pancreatitis.

Acute Disease↗
PubMed2005

Animal models and analytical approaches for understanding the relationships between wine and cancer.

We used two approaches for studying the relationships between wine consumption, wine composition and cancer In the first approach, a transgenic mouse model of human neurofibromatosis, combined with the use of well-defined, chemically purified diets, showed that red wine contains nonalcoholic components that can delay tumor onset. In additional studies, catechin, the main monomeric polyphenol of red wine, delayed tumor onset in this mouse model in a positive, linear relationship when incorporated into the diet at levels of 0.5-4 mmol/kg diet. In the second approach, low doses of the chemical carcinogen 2-amino-1-methyl-6-phenylimidazo(4, 5-b)pyridine (PhlP) were administered to rats, and formation of DNA adducts was evaluated by accelerator mass spectrometry. Consumption of red wine solids (the residue from red wine remaining after removal of alcohol and water) and the wine polyphenol quercetin did not influence PhlP-DNA adduct levels or induce liver enzymes (glutathione-S-transferase and quinone reductase). However, quercetin did alter distribution of PhlP in the rat tissues compared to control animals and animals fed other potential dietary chemopreventive agents, including phenylethyl isothiocyanate and sulforaphane. These studies demonstrate the feasibility of these approaches for studying the chemopreventive potential of dietary components at physiologic levels in

Animals↗
PubMed1991

Setting the optimal erythrocyte protoporphyrin screening decision threshold for lead poisoning: a decision analytic approach.

Erythrocyte protoporphyrin (EP) was introduced in the 1970s as an inexpensive screening test for lead poisoning. As greater knowledge of lead poisoning has accumulated, the recommended EP level at which further evaluation for lead poisoning should be initiated has been lowered from greater than or equal to 50 micrograms/dL to greater than or equal to 35 micrograms/dL. The purpose of this study was to evaluate the utility of this EP threshold. A receiver operator characteristic curve was constructed to assess the relationship between the true-positive rate and false-positive rate of EP at various decision thresholds. The receiver operator characteristic curve was constructed with data from the second National Health and Nutrition Examination Survey from 1976 to 1980, which included 2673 children 6 years of age or younger who had both blood lead and EP level determinations. Decision analysis was then used to determine the optimal EP decision threshold for detecting a blood lead level greater than or equal to 25 micrograms/dL. The receiver operator characteristic curve demonstrated that EP is a poor predictor of a blood lead level greater than or equal to 25 micrograms/dL. At the currently recommended EP decision threshold of 35 micrograms/dL, the true-positive rates and false-positive rates of EP are 0.23 and 0.04, respectively. As a result of the inadequate performance of EP screening for lead poisoning, when the prevalence of lead poisoning is greater than 8%, there is no EP decision threshold that optimizes the relationship between the cost of screening normal children and the benefit of detecting lead-poisoned children. Erythrocyte protoporphyrin measurement is not sufficiently sensitive to be recommended uniformly as a screening test for lead poisoning.

Child↗
PubMed1990

Analytical approaches to detection and characterization of disease-linked chromosome aberrations.

Flow karyotyping and FISH with chromosome specific or disease-locus-specific probes are powerful adjuncts to conventional cytogenetic analysis. Flow karyotyping is well suited to quantitative analysis of DNA content changes that occur during structural rearrangement. FISH with probes for repeated sequences allows ready detection of aneuploidy in interphase cells. FISH with whole chromosome composite probes to metaphase spreads facilitates detection of subtle structural changes and allows detection of structural aberrations that occur at frequencies as low as 10(-3). FISH with locus-specific probes facilitates diagnosis of specific genetic diseases, allows phenotype-genotype correlation on a cell-by-cell basis and may be developed into a sensitive method for detection of residual disease.

Chromosome Aberrations↗
PubMed1990

[Behavior analytic approaches of research in psychiatry].

Biologically oriented psychiatric research usually relies more on abstract nosological concepts than on purely descriptive psychopathological syndromes. However, biological validation of psychiatric diagnoses has not been possible so far. More recent findings emphasize the nosological unspecificity, but syndromal specificity of biological data. It seems promising therefore to differentiate psychopathological descriptions more clearly by using objective methods of behavioural assessment and analysis. Concept, methods and examples of this empirical approach will be outlined.

Humans↗
PubMed1988

Modulation of cell proliferation by protein proteinase inhibitors. A new analytical approach.

Human alpha 1-proteinase inhibitor (alpha 1-antitrypsin) and bovine pancreatic trypsin inhibitor both inhibit cell-surface proteolytic activity in human fibroblasts. At the inhibitory concentrations, these proteins also inhibit cellular proliferation, as assayed by a microassay based on spectrophotometry of fixed and stained cells. Despite testing a wide range of proteinase inhibitor concentrations, no evidence was found for mitogenic or growth-stimulatory activity. ovomucoid was inactive against cell-surface proteinase activity and did not inhibit cellular proliferation.

Cell Division↗