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PubMed1997

[A study of cerebral maturity by means of quantitative analysis of the electroencephalogram].

INTRODUCTION AND OBJECTIVE: The objective of this study is to evaluate cerebral maturity by means of quantitative analysis techniques applied to the electroencephalogram (EEG). MATERIAL AND METHODS: A transversal study of cerebral maturity was carried out in 403 persons who had undergone an EEG. A previous pilot study had been carried out of 103 persons. A series of spectral parameters of the EEG were selected so that all those studied were in the most similar conditions possible. Different frequency bands were analyzed choosing the one with best discrimination of the maturity aspect. Classification of the different levels of cerebral maturity was done with the help of multivariant analysis. The value of the median of the frequencies and the spectrum of relative potencies at the moment when a frequency band is at a maximum are the parameters which evolve best with age and best discriminate maturity Spectral analysis allows selection of the frequency bands most suitable to the problem. Working with two frequency bands is sufficient to evaluate cerebral maturity. RESULTS: The variables obtained in the occipital channels were sufficient for evaluation of cerebral maturity. Those of the right hemisphere were more significant for diagnosis. The occipital channels are the most relevant in the study of cerebral maturity. CONCLUSIONS: The neuronal network is the most efficient classifier for classification of different groups of maturity The next most efficient method is by quadratic discriminant analysis. Consideration of the variables, taking into account the factors of stability and regularity of the EEG signals improves discrimination with respect to the average of those recorded during the entire procedure.

Adolescent↗
PubMed1999

Quantitative analysis of expression of mouse sialyltransferase genes by competitive PCR.

The present paper describes a rapid and systematic method for semi-quantitative analysis of the expression of sialyltransferase genes. So far, fifteen sialyltransferase cDNAs have been cloned from mice. Most of these genes are expressed in developmental stage-dependent and/or tissue-specific manners, and the expression levels of some of them are too low to detect on Northern blot analysis. To resolve how each sialyltransferase contribute to synthesize sialylglycoconjugates, it is necessary to establish the method for quantification of gene expression levels of these fifteen sialyltransferases. Therefore, we developed a competitive PCR-based method for analyzing the quantitative relationship of the gene expression of fifteen sialyltransferases. Using this method, we can investigate the levels of gene expression of sialyltransferases in various cell lines and various tissues of mice, and can accurately determine their expression levels.

Animals↗
PubMed1994

Three-dimensional molecular shape analysis-quantitative structure-activity relationship of a series of cholecystokinin-A receptor antagonists.

The three-dimensional molecular shape analysis-quantitative structure-activity relationship (3D-MSA-QSAR) technique has been applied to develop correlations between the calculated physicochemical properties and the in vitro activities of a series of 3-(acylamino)-5-phenyl-2H-1,4-benzodiazepine cholecystokinin-A (CCK-A) antagonists. 3D-MSA-QSARs were developed for varying subsets of 53 analogs (J. Med. Chem. 1988, 31, 2235-2246). An active conformation is hypothesized for these compounds using the loss in biological activity-loss in conformational stability principle. After placing all compounds in the active conformation and performing pairwise molecular shape analysis, it was determined that not any one analog serves as the best shape reference compound. Nonidentical volumes of allowed receptor space are mapped out by different antagonists. A shape reference compound that consists of selected overlapped structures expands the definition of the accessible receptor space. This type of mutant improves the predicted activity of analogs over the value predicted if only one compound is chosen as the reference. Molecular shape, as represented by common overlap steric volume and nonoverlap steric volume, is the major factor contributing to the affinity of this class of compounds. Intramolecular conformational stability, as measured by the difference in energy of the active conformation and the global minimum energy conformation, is also important. It is further concluded from the 3D-MSA-QSAR models that part of the binding pocket for the 3-amido substituent has a preference for lipophilicity. The method used in this study of fragmenting the antagonist into spheres of varying radii and measuring lipophilicity isolates the substructure with highest probability of interacting with the receptor. Two indicator variables marking the presence of an N-methyl group and an o-fluoro atom on the 5'-phenyl substituent of the benzodiazepine ring structure also contribute significantly to the 3D-MSA-QSAR models. The 3D-MSA-QSAR results have led to the proposal of a 3D pharmacophore model for the benzodiazepine CCK-A antagonists.

Animals↗
PubMed1992

Significance and quantitative analysis of von Willebrand factor in human platelets.

The von Willebrand factor (vWF) is found in plasma and in platelets. The concentration and multimeric composition of the vWF in platelets of 160 patients with bleeding tendency were examined since very little is known about the platelet vWF. For quantitative analysis of the platelet vWF, a modified ELISA was established. A reference range from 70%-130% of platelet vWF concentration considered normal was established by examining 80 healthy blood donors. 16.9% of the 160 patients showed a decreased vWF concentration in platelets only, while all the other coagulation parameters were normal. 3 of our patients belong to the same family and suggesting an autosomal dominant genetic transmission for the von Willebrand disease type 1-3. The data also suggests, that a quantitative and qualitative analysis of the vWF in plasma and platelets is required for an exact diagnosis of the von Willebrand disease.

Blood Donors↗
PubMed2006

Quantitative analysis of paracetamol polymorphs in powder mixtures by FT-Raman spectroscopy and PLS regression.

A fast and simple method for the quantitative analysis of monoclinic (form I) and orthorhombic (form II) paracetamol was developed, based on FT-Raman spectroscopy and PLS regression. Three different preprocessing algorithms, namely orthogonal signal correction (OSC), standard normal variate transformation (SNV) and multiplicative scatter correction (MSC), were applied in order to eliminate effects caused by sample preparation and sample inhomogeneities. Subsequently, PLS regression models were fitted and their predictive performance was evaluated on the basis of the root mean squared error of cross-validation (RMSECV) over the complete data set. Furthermore, the data were split into two equal-sized training and test subsets by the Kennard-Stone design and the errors of calibration (RMSEC) and prediction (RMSEP) were calculated. It was found that the OSC preprocessing contributes to a significant increase in the predictive performance of the PLS regression model (RMSECV=0.500%, RMSEC=0.842% and RMSEP=0.538%) in the overall concentration range of form I, compared to the SNV (RMSECV=2.398%, RMSEC=0.911% and RMSEP=7.177%) and MSC (RMSECV=2.7648%, RMSEC=1.572% and RMSEP=4.838%). In addition, the model developed on OSC preprocessed data is more parsimonious, requiring a single latent variable, compared to three latent variables required by the models fitted to the SNV and MSC preprocessed data. The proposed multivariate calibration presents a significant improvement over existing methods for the quantitation of paracetamol polymorphs.

Acetaminophen↗
PubMed2004

Differentiation of thyroid nodules using Tl-201 scintigraphy quantitative analysis and fine-needle aspiration biopsy.

We studied the differentiation of thyroid nodules using fine-needle aspiration biopsy (FNA) and Tl-201 scintigraphy quantitative analysis. One-hundred and thirty-one thyroid nodules were examined: 83 follicular lesions (58 benign and 25 malignant lesions) and 48 non-follicular lesions (8 benign and 40 malignant lesions). During Tl-201 scintigraphy examinations, an early and a delayed image were acquired 10 and 120 min after an intravenous injection, respectively. The T/N ratio (counts of nodular lesion/counts of contralateral normal thyroid tissue) of each image was calculated quantitatively. We assessed the ability of the Tl-201 scintigraphy and of the FNA analysis to differentiate benign and malignant lesions and determined the cut-off levels for the assays. For the follicular lesions, the area under the ROC (Receiver Operating Characteristic) curve (Az) for the Tl-201 scintigraphy data was greater than that for the FNA data. For the non-follicular lesions, the Az for the FNA data was greater than that for the Tl-201 scintigraphy data. We set cut-off levels at 1.370 for follicular lesions, and 1.070 for non-follicular lesions. The sensitivity and specificity were 76% and 82.7% for follicular lesions, and 90% and 87.5% for non-follicular lesions, respectively. The overall accuracy of the analysis was 84.0%.

Adenoma↗
PubMed1996

Immunolocalization of cellular glutathione peroxidase in adult rat lungs and quantitative analysis after postembedding immunogold labeling.

To determine the distribution of cellular glutathione peroxidase in rat lungs, the tissues were stained immunohistochemically. Quantitative analysis was performed in certain cell types of alveolar linings, after the ultrathin sections were stained by a postembedding immunogold technique. Immunoblot analysis revealed that homogenates of rat liver, heart, and lungs all gave a single band. Under the light microscope, the following tissues were stained intensely: epithelial cells, smooth muscle cells and glands of bronchi and bronchioles, type II alveolar cells, and alveolar macrophages. Under immunoelectron microscopy, type II alveolar cells and macrophages were abundant in mitochondria. The mitochondria, nucleus, and cytoplasm of macrophages were labeled almost twice as densely as the respective compartments of type II alveolar cells. Within cell types, the mitochondria were labeled twice as densely as the nuclei. The other particles were less than half as densely labeled as the nuclei. The labeling was slightly less dense in the cytoplasm than in the nucleus. The present study revealed that glutathione peroxidase occurred predominantly in the epithelial linings and metabolically active sites in rat lungs. The tissues that were previously found to be rich in superoxide dismutases were also rich in glutathione peroxidase.

Animals↗
PubMed1996

Quantitative analysis of changes in cell proliferation and apoptosis during preneoplastic and neoplastic stages of hepatocarcinogenesis in rat.

In situ markers for quantitative analysis of cell proliferation and apoptotic cell death have been used to evaluate both the proliferation level and net growth potential of preneoplastic nodules and malignant tumor tissues from rats experimentally induced for hepatocarcinogenesis by the dietary administration of 2-acetylaminofluorene. The findings show that although tumors have a much higher level of cell proliferation than preneoplastic liver nodules, the nodules have a higher potential for net growth when apoptosis is taken into account. These results support a role for a decrease in apoptosis during the promotion stage of carcinogenesis.

2-Acetylaminofluorene↗
PubMed1995

Quantitative analysis of fosinopril sodium by capillary zone electrophoresis and liquid chromatography.

A capillary zone electrophoresis (CZE) method was developed for the quantitative analysis of fosinopril sodium. Validation parameters of the CZE method were evaluated and compared to an existing LC method. In terms of precision and sensitivity. LC performance was superior to that of the CZE method for this application. The CZE method achieved better selectivity for several degradants of interest within a much shorter analysis time than did the LC method. Effects of detection wavelength, applied voltage and buffer concentration on optimization of the CZE method are presented. Effects of diluent composition on capillary loading and peak behaviour are also discussed.

Buffers↗
PubMed1996

Assessment of the progression of emphysema by quantitative analysis of spirometrically gated computed tomography images.

RATIONALE AND OBJECTIVES: The authors assessed the progression of pulmonary emphysema by means of quantitative analysis of computed tomography images. METHODS: Twenty-three patients suffering from emphysema due to an alpha 1-antitrypsin deficiency, aged 45 +/- 7 years and exsmokers, were scanned twice with a 1-year time interval. At 90% of the vital lung capacity, slices with a thickness of 1.5 mm were acquired at the level of the carina and 5 cm above the carina; slices with a thickness of 1 cm were acquired 5 cm below the carina. The entire lung was scanned spirally at a respiratory status, corresponding with 75% of the total lung capacity at baseline. The mean lung densities (MLD) were calculated in an objective manner with new analytic software featuring automated detection of the lung contours. RESULTS: Mean lung densities decreased by 14.2 +/- 12.0 Hounsfield units (HU; P < 0.001) above the carina, by 18.1 +/- 14.4 HU (P < 0.001) at the carina level, by 23.6 +/- 15.0 HU (P < 0.001) below the carina, and by 12.8 +/- 22.2 HU (P < 0.01) for the entire lung. The decrease in MLD was most obvious in the lower lung lobes. For the same patient group, the annual decrease in the forced expiratory volume (FEV1) and the carbon monoxide-diffusion were 120 +/- 190 mL (P < 0.01) and 10 +/- 70 mmol/kg/minute ( P < 0.2), respectively. No significant correlation was found between the decrease in MLD and the decrease in FEV1. CONCLUSIONS: Progression of emphysema can be assessed in an objective manner based on the mean lung density (MLD), measured from computed tomography volume scans as well as from single-slice scans. Mean lung density has proved to be more sensitive than FEV1 and carbon monoxide-diffusion.

Adult↗
PubMed2001

Quantitative analysis of the frequency spectrum of the radiation emitted by cytochrome oxidase enzymes.

A physical model is proposed that provides a quantitative analysis of the energy emitted by proton flows through mitochondrial walls. The model developed is based on biochemical and biophysical properties of the enzyme cytochrome oxidase and in particular the embedded heme groups that are involved in the electron ferrying mechanism. The estimates of the energies at approximately 1.1 eV and corresponding wavelengths of the near infrared radiation generated, with a peak close to 900 nm, agree extremely well with experimental values. The basic idea in the mechanism proposed is that the passage of a proton through the mitochondrial wall's gate is linked with the creation of a virtual proton-electron pair in an excited state of a hydrogen atom. The electron is temporarily removed from the enzyme when the proton arrives at the gate and is subsequently deposited back at the enzyme's acceptor site when the proton leaves the gate.

Biophysical Phenomena↗
PubMed2002

Quantitative analysis of dental porcelain surfaces following different treatments: correlation between parameters obtained by a surface profiling instrument.

This investigation compared, by quantitative analysis, the surface roughness of dental porcelain submitted to three different treatments (glaze, trimming and polishing), utilizing a surface profiling instrument. The parameters Ra (median roughness), Rz (median of the maximum profile heights of five sample lengths), Rpm (median of the maximum profile heights related to the median line of five sample lengths), Pc (peak count per centimeter) and Rpm/Rz (proportional parameter) were evaluated. In addition, the correlation between Ra and the other parameters was analyzed. Based on the results obtained, it was seen that the Ra parameter did not present any correlation with the other parameters in some of the situations evaluated. This demonstrates that complementation of the measurement with other parameters is always necessary, providing a better evaluation of the functional properties of a surface.

Analysis of Variance↗
PubMed1999

Quantitative analysis of cell-free Epstein-Barr virus DNA in plasma of patients with nasopharyngeal carcinoma.

Using real-time quantitative PCR, cell-free EBV DNA was detectable in the plasma of 96% (55 of 57) of nasopharyngeal carcinoma (NPC) patients (median concentration, 21058 copies/ml) and 7% (3 of 43) of controls (median concentration, 0 copies/ml). Advanced-stage NPC patients had higher plasma EBV DNA levels than those with early-stage disease. At 1 month after completion of radiotherapy, plasma EBV DNA was undetectable in 7 of 15 subjects (47%) but remained high in the remaining 8 subjects (53%). Clinical examination revealed that all of the former seven subjects had complete tumor regression, whereas six of the eight latter subjects exhibited evidence of disease persistence or had developed distant metastases. These results suggest that quantitative analysis of plasma EBV DNA may be a useful clinical and research tool in the screening and monitoring of NPC patients.

DNA, Viral↗
PubMed1990

[Quantitative analysis of collagen fiber in keratoconus].

In order to identify the direct pathogenic factors involved in the stromal thinning of keratoconus, quantitative analysis of keratocytes, collagen fibers and collagen lamellae in keratoconus cornea was performed histologically by light and electron microscopy. Both normal and keratoconus corneas showed a similar cell density of keratocytes in the central stroma, therefore the total number of keratocytes in keratoconus cornea might be smaller than that of controls, because of the thinning of stroma in the keratoconus. The collagen lamellae in keratoconus corneas showed a significant decrease in number compared with controls. There was a direct relationship between the stromal thickness and number of collagen lamellae. On the other hand, there was no statistical significance between normal and keratoconus corneas in terms of the thickness of collagen lamellae. These results suggest that the thinning of the cornea in keratoconus might occur as the result of a defect of some collagen lamellae due to a disorganization during the process of collagen lamellae formation.

Adolescent↗
PubMed1996

Quantitative analysis of triglycerides using atmospheric pressure chemical ionization-mass spectrometry.

Atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) was used for quantitative analysis of triglycerides (TG) separated by reverse-phase high-performance liquid chromatography. APCI-MS was used for analysis of mono-acid TG standards containing deuterated internal standard, of a synthetic mixture of heterogeneous TG, of randomized and normal soybean oils and of randomized and normal lard samples. Quantitation of the TG by four approaches based on APCI-MS were compared, and these were compared to quantitation obtained using liquid chromatography (LC) with flame-ionization detection (FID). The APCI-MS methods were based on (i) calibration curves from data for mono-acid TG standards, (ii) response factors obtained from a synthetic mixture of TG, (iii) response factors calculated from comparison of randomized samples to their statistically expected compositions, and (iv) response factors calculated from comparison of fatty acid (FA) compositions calculated from TG compositions to FA compositions obtained by calibrated gas chromatography (GC) with FID. Response factors derived from a synthetic mixture were not widely applicable to samples of disparate composition. The TG compositions obtained using APCI-MS data without application of response factors had average relative errors very similar to those obtained using LC-FID. Numerous TG species were identified using LC/APCI-MS which were undetected using LC-FID. Two quantitation methods, based on response factors calculated from randomized samples or on response factors calculated from FA compositions, both gave similar results for all samples. The TG compositions obtained using response factors calculated from FA compositions showed less average relative error than was obtained from LC-FID data, and were in good agreement with predicted compositions for the synthetic mixture and for randomized soybean oil and lard samples.

Chromatography, High Pressure Liquid↗
PubMed2003

Quantitative analysis of colorectal tissue microarrays by immunofluorescence and in situ hybridization.

The accuracy and reliability of in situ studies may be compromised by qualitative interpretations. Quantitation imposes a greater degree of objectivity, is more reproducible, and facilitates the clarity of definitions. The aim of this study was to validate the utility of laser imaging systems for the in situ quantitative analysis of gene expression in tissue microarrays. Immunofluorescence was employed to quantify the expression of the tumour suppressor p53, a marker of proliferation (Ki67), an endothelial cell marker (CD31), and the mismatch repair proteins human Mut L homologue 1 and human Mut S homologue 2 in an arrayed series of colorectal tissues (n = 110). Quantitative data on this panel of antigens were compared objectively with qualitative scoring of immunohistochemical chromogen deposition. In addition, the expression of vascular endothelial growth factor (VEGF)-A, placental growth factor, hepatocyte growth factor, and c-Met mRNA was quantified by phosphor image analysis of in situ hybridization reactions. The quantified data on p53, Ki67, and CD31 expression were significantly associated with the pathologist's score (p < or = 0.001). While hepatocyte growth factor and placental growth factor were not up-regulated, c-Met expression was increased up to 2.5-fold and the median VEGF-A expression was elevated 4-fold (p = 0.003) in this series of colorectal tumours. Laser imaging systems are therefore feasible for high-throughput, quantitative profiling of tissue microarrays.

Biomarkers, Tumor↗
PubMed1984

Quantitative analysis of prostanoids in biological fluids by combined capillary column gas chromatography negative ion chemical ionization mass spectrometry.

An assay for the quantitative analysis of six biologically important prostanoids based on combined gas chromatography negative ion chemical ionization mass spectrometry has been developed. Prostanoids were extracted from biological fluids by liquid chromatography on Sep-Pak cartridges and converted to pentafluorobenzyl ester derivatives. Samples were injected on capillary column by the splitless technique and injections were made in a high boiling hydrocarbon solvent (n-dodecane) in order to minimize chromatographic run times. Quantification was carried out using selected ion monitoring of the appropriate [M-pentafluorobenzyl]- anion. The assay has been used for profiling cyclooxygenase metabolites of arachidonic acid in guinea pig lung perfusate after induction of anaphylaxis and platelet rich plasma after collagen-stimulated aggregation.

Animals↗
PubMed1982

Optical diffraction as a tool for semiautomatic, quantitative analysis of tissue specimens.

Optical diffraction was tested on electron micrographs of normal and malformed myelin sheaths as a method for semiautomatic quantitative analysis of tissue specimens. Both normal and malformed myelin sheaths were chosen for the analysis because of their characteristic internal structure and its alteration as a result of malformation. Optical diffraction patterns were obtained by means of an optical diffractometer coupled with a digital detector. The spacing and arrangement of the components of various types of myelin sheath were automatically calculated and determined and the results were verified with discriminant analysis. Out of 27 parameters of the radial and out of 25 parameters of the angular distributions of diffracted light intensity, 6 and 11, respectively, were found to have good discriminative power and were used for classification of myelin sheaths. The accuracy of automatic classification was tested by comparison with myelin sheath types of known origin. The samples visually similar by their appearance, e.g. control and regenerating myelin sheaths, were automatically classified with accuracy of 69%, whereas others were classified appropriately with 88-100% accuracy. It is believed that this kind of analysis may successfully be applied for specimens of other tissues and/or organs.

Animals↗