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Results for “quantitative analysis”

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PubMedDate not supplied

The quantitative analysis of inhalational anaesthetics in forensic samples by gas chromatography/mass spectrometry/selected ion monitoring.

The quantitative analysis of volatile anaesthetics for biomedical applications by means of gas chromatograph/mass spectrometry/selected ion monitoring (GC/MS/SIM) was studied. Xenon gas was selected as an internal standard for the assay by adding to a closed system, because of its stability and inactivity. In the assay of inhalational anaesthetics, isoflurane and nitrous oxide (laughing gas), in forensic samples (serum and cerebrospinal fluid), the calibration of the anaesthetic was linear from 0.12 to 12 nmol/mL in isoflurane and from 30 to 300 nmol/mL in nitrous oxide. Our results suggest that this new method is suitable for the quantitative analysis of inhalational anaesthetics in the biomedical field.

Anesthetics, Inhalation↗

PubMedDate not supplied

A quantitative analysis of the afferent innervation of the organ of corti in guinea pig.

A quantitative analysis of the afferent innervation of the organ of Corti was made on normal and vestibular nerve-sectioned guinea pigs. Section of the vestibular nerve at the internal auditory meatus provided an efficient means of eliminating the efferent innervation to the cochlea without significant loss of afferent fibres. Nerve counts on normal and de-efferented animals revealed that about 10-15 % of the cochlear afferent innervation supplies the outer hair cells. The remaining 85-90% of afferent fibres innervate the inner hair cells. As in cats, all tunnel spiral bundle fibres and upper tunnel crossing fibres were efferent to outer hair cells. Since unmyelinated fibres in the osseous spiral bundle were not counted, quantitative analysis of the efferent innervation to inner hair cells could not be made. However, a significant loss of myelinated fibres in the osseous spiral lamina after vestibular nerve section confirms that many myelinated efferent fibres are present in this region.

Animals↗

PubMed1983

[Qualitative and quantitative analysis of regional contraction disorders using levocardiograms].

In 74 patients with proven myocardial infarction (typical history and enzymes, diagnostic ECG, and stenosis of the vessel supplying the asynergic region of more than 75%) the results of qualitative analysis of left ventricular cineangiograms were compared to those of quantitative analysis using the radial axis method of Mathes. There was a significant difference in interpretation between the two methods if the physiological movements of the heart were not taken into account in the qualitative analysis. After correction for systolic anterior movement and downward movement of the aortic valve during systole, a mean accuracy of 92% resulted. The radial axis method discriminated well between normokinetic and asynergic wall segments. However, this method proved less useful for the detection of asynergies in the apical, anterobasal, and posterobasal regions. A radial axis angle of between 15 degrees and 20 degrees is considered to be optimal. The quantitative analysis seems to be particularly useful for the interpretation of borderline cases, and should be carried out routinely in addition to the qualitative analysis.

Adult↗

PubMed1994

Quantitative analysis of vibrational circular dichroism spectra of proteins. Problems and perspectives.

Experimental and computational aspects of the quantitative analysis of vibrational circular dichroism (VCD) of proteins are discussed. Experimentally, the effect of spectral resolution, sample concentration, cell selection and spectral normalization effects are considered. The influence of random intensity variations on the results of quantitative analysis of amide I' VCD are shown to be minor up to a 15% variation in spectral intensity. A computational algorithm, based on factor analysis of the spectra and multiple linear regression calculation of fractions of secondary structures (FC), was designed to analyse quantitatively the details of the VCD spectra-structure relationship. It also enabled the results of VCD measured independently for the amide I' and amide II regions to be combined. Our study is based primarily on the optimization of the calculation to predict FC values for proteins not included in the reference data set used for regression. The best prediction is obtained with the function using only part of the observable independent VCD spectral components. Inclusion of all components actually reduces the prediction accuracy of the analysis. Spectroscopic reasons for such behaviour and the consequences of the interdependence of the crystallographic FC values on the spectra-structure analysis are discussed. Finally, the possibility of utilizing VCD spectra to obtain quantitative structural information about the protein beyond the conventional secondary structure composition is explored. A matrix descriptor of super-secondary structure features for proteins is designed, and preliminary results for prediction of this descriptor from amide I' VCD spectra are presented. These latter calculations use a novel design of the back-propagation neural network.

Circular Dichroism↗

PubMed1990

[Quantitative analysis of background activity using ambulatory EEG monitoring system].

We studied a possibility of the quantitative analysis of background activities using ambulatory EEG monitoring system (AEEG). (1) This recorder system had a stable frequency characteristics from 1.0 Hz to 20 Hz, in which range the background activities on EEG were organized, and also had a good lineality of amplitude until 150 microV. Therefore, this system had no hindrance in quantitative analysis of EEG background activities. (2) We selected the method of continuous spectrum array (CSA) to analyse the records using AEEG. The CSAs at awakening, light sleep and deep sleep respectively revealed the characteristic patterns of spectrum. And, in the long-term examination of CSA during sleep, the dynamic alternation of spectrum was well recognized depending on the change of sleep stages. This method was useful to the evaluation of sleep cycle as well as the judgement of consciousness level. The AGGE has many advantages compared with the other long-term EEG systems. Major advantages are as follows: 1) The patient can move freely with this equipment. 2) A whole day's record can be stored on a cassette. 3) The operative technique is easy. The clinical and research application of AEEG may be more expanded to combine with the various computer analysing methods.

Electrocardiography, Ambulatory↗

PubMed1994

Multicenter trial validation for quantitative analysis of same-day rest-stress technetium-99m-sestamibi myocardial tomograms.

UNLABELLED: The accuracy of an automated quantitative analysis of same-day rest/stress 99mTc sestamibi SPECT images for detection and localization of coronary artery disease (CAD) was assessed in a multicenter trial consisting of 161 patients from 7 different clinical sites utilizing various camera computer systems. METHODS: Of the 161 patients, 102 had angiographically documented coronary artery disease, 22 had normal coronary arteriograms, and 37 had a low (< 5%) likelihood of coronary artery disease based on their age, sex, symptoms and the results of their exercise electrocardiograms. The patients were studied using previously optimized image acquisition and processing protocols. An additional population consisting of 45 patients with single-vessel disease were evaluated to determine the optimal criteria for detection of CAD. RESULTS: The quantitative analysis method was associated with an overall sensitivity of 87%, specificity of 36%, and normalcy rate (true negative rate in the low likelihood patients) of 81%. Sensitivity for overall detection of disease was similar (90%) in patients with and without myocardial infarction (90% versus 89%). The sensitivities and specificities for identification of disease in individual coronary arteries were, respectively, 69% and 76% for LAD, 70% and 80% for LCX, and 77% and 85% for RCA. CONCLUSION: The results of this study demonstrate that the new objective quantitative method for analysis of same-day rest/stress 99mTc sestamibi SPECT images is accurate for detection and localization of CAD and correlates highly with expert visual interpretation.

Adolescent↗

PubMed1985

Improved reproducibility and quantitative analysis of phospholipids by flame ionization detection.

Quantitative analysis of phospholipids by flame ionization was improved by careful application of samples with a Hamilton syringe and use of a sealed dual tank system. Chromarods developed more consistently with reproducible scanning times or RF values (coefficient of variation of 1%) and with sharper peaks if development was carried out in a sealed dual tank system. The Chromarods were placed in the inner tank, which was the standard ground glass topped tank furnished with the Iatroscan TH-10 system. This inner tank was placed inside a larger thin-layer chromatography tank which was sealed with silicone grease and the lid held in place with a lead brick. Both tanks were lined with absorbent paper and contained the same solvent system. Biological samples quantified with these procedures and measured in amounts between 1 and 30 micrograms had coefficients of variation between 0.2 and 6%. An efficient method of completely separating neutral lipids from phospholipids and allowing quantitative determination of cholesterol is described. Scanning times and RF values of various phospholipids are compared to determine the best separation of the major phospholipids found in 3T3-L1 and leukocyte membranes.

Cell Membrane↗

PubMed1996

Quantitative analysis of mixtures of metal-carbonyl complexes by Fourier-transform infrared spectroscopy: application to the simultaneous double immunoassay of antiepileptic drugs by the nonisotopic carbonyl metalloimmunoassay method.

The feasibility of a double immunoassay of haptens by the nonisotopic carbonyl metalloimmunoassay (CMIA) method is demonstrated. Three different pairings of antiepileptic medications from the groups carbamazepine, diphenylhydantoin, and phenobarbital (for each of which a mono-CMIA is already available) were assayed by double CMIA. The assay method employs as tracers metal-carbonyl complexes that give very strong signals in the range of 1850-2200 cm-1 in the infrared spectrum, permitting quantitative analysis by Fourier-transform infrared spectroscopy. The fact that the signals are individually assignable and of comparable intensity permits quantitative analysis of mixtures of two tracers. The analysis may proceed in one of two ways: in the simpler case, there is no peak overlap with the two tracers and the quantitative analysis can be performed by simply measuring the absorbance of characteristic peaks of the two tracers. In the second case, in which there is partial or total overlap of peaks, a stepwise calculation provides rapid quantification of the two tracers. These findings allowed us to perform the double CMIA of two antiepileptics in which experimental conditions and time of analysis were strictly identical to those for mono-CMIA. We show here that there is a very good correlation between the results obtained in mono- and double-immunoassay by the CMIA method (correlation coefficient > 0.990).

Animals↗

PubMed1992

Quantitative analysis in single photon emission tomography (SPET).

Quantitative analysis can improve the sensitivity and specificity of single photon emission tomography (SPET) procedures, as well as reduce inter- and intraobserver variabilities. Quantification of the radioactivity distribution is the ultimate goal of SPET. In this review we consider the basic requirements for an optimum three-dimensional reconstruction of the radionuclide distribution to enable quantification. Attenuation and scatter correction as well as varying resolution are the major problems. In the older SPET systems quantification was hampered by the lack of system sensitivity and sufficient computer power. Therefore, the imaging system was often assumed to be shift invariant and linear and the attenuation throughout the object uniform. More sophisticated solutions have been proposed and with more or less success implemented, but not for application in daily practice. Knowledge (measurement) of the attenuation is often required. New generation SPET systems employing multi-detectors and super minicomputers will ease the implementation of these solutions.

Humans↗

PubMed1977

The early phase of insulin release in man--a new method for quantitative analysis.

A method is presented for the quantitative analysis of early insulin release in man. There were measured arterial insulin levels after glibornuride administered intravenously. The mathematical procedure has been modified: Modification I is based on the assumption that early insulin release represents a wave like insulin delivery, modification II is based on the assumption that this insulin bolus is immediately followed by a slower insulin release which must be distinguished from the second phase of insulin release. For the calculations there was used a "primary insulin space" derived from experiments with exogenous insulin. The results of calculations were varying up to 1.5 units of early insulin release in healthy volunteers receiving glibornuride with dosages varying up to 50 mg. The value of the presented method for examinations of insulin release for theoretical and clinical purposes is discussed.

Adult↗

PubMed1977

Quantitative analysis in the oxytocin challenge test.

A quantitative analysis of the oxytocin challenge test (OCT) was carried out in 305 women to evaluate: (1) the intrauterine pressures evoked during the oxytocin infusion, (2) when fetal heart rate (FHR) decelerations are likely to occur, (3) the type and amount of decelerations which are significant, and (4) what clinical events and laboratory parameters correlate with the OCT. If contractions are evoked at a rate of three per 10 minutes, the pressure profile mimics normal labor. The first FHR deceleration is likely to occur between the second and third effective contraction. A deceleration/contraction ratio greater than or equal to 10% significantly forecasts an abnormal FHR during parturition and an increased chance of a cesarean section.

Adult↗

PubMed1997

Long-lasting abnormalities in cardiac sympathetic nervous system in patients with coronary spastic angina: quantitative analysis with iodine 123 metaiodobenzylguanidine myocardial scintigraphy.

Quantitative analysis of iodine 123 metaiodobenzylguanidine (MIBG) myocardial tomographic imaging showed that the regional uptake reduction and abnormally high washout of MIBG in the myocardial territories of the coronary artery with spasm were observed in 33 (75%) and in 30 (68%) of 44 patients with coronary spastic angina, whereas it was observed in two (7%) and in four (15%) of 27 control subjects, respectively. The patients with higher disease activity of the anginal attack and those with life-threatening ventricular arrhythmias were frequently associated with either the uptake reduction or the abnormally high washout of MIBG (91% in patients with high disease activity, 100% in patients with ventricular arrhythmias). The repeated studies of MIBG myocardial tomographic imaging at 2 and 6 months after suppression of anginal attacks by medical treatments showed that the scintigraphic abnormalities still remained in 85% of the patients at 2 months and 32% at 6 months. Thus the abnormalities in sympathetic nervous system assessed with MIBG scintigraphy has been shown to be highly associated with patients with coronary arteries with spasm, particularly high-risk patients, and lasted for several months despite suppression of anginal attack.

3-Iodobenzylguanidine↗

PubMedDate not supplied

Computer assisted mapping in quantitative analysis of cerebral positron emission tomograms.

For quantitative analysis of CT of the brain, an interactive FORTRAN program was developed to provide a time saving mapping procedure with high, largely user-independent reproducibility and flexible adaptation to individual anatomical variations. Program scope and functions are demonstrated, and results obtained in a group of seven normal volunteers are presented for positron emission tomography using the [18F]-2-fluoro-2-deoxy-D-glucose (FDG) method. Basically, the procedure is designed as a two step process: first, a region raw contour is defined geometrically on the basis of local Cartesian or polar coordinates relative to the whole brain contour; second, the final region is delimited within the raw region, in the FDG images according to relative local tissue activity. Although all parameters for mapping a brain slice are stored in a standard parameter file ensuring reproducibility and comparability, interactive control of all steps permits user-guided corrections whenever necessary. Numerical results closely correspond to the data obtained in a previous study of normal subjects with individual manual mapping; discrimination between gray and white matter is in good agreement with theoretical predictions. The program can be easily adapted to other CT techniques.

Brain↗

PubMed1993

[Quantitative analysis for mast cells in obstructive sialadenitis].

Quantitative analysis for mast cells in 27 cases of obstructive sialadenitis, 12 cases of approximate normal salivary gland tissues and 5 cases of lymphoepithelial lesion of salivary glands shows that the number of mast cells is slightly increased with the increase of gravity-grade of obstructive sialadenitis and this is closely related to fibrosis of salivary glands and infiltration grade of inflammation cells (dominated by lymphocyte cells), whereas not closely relating to the age change of patients. For the cases of benign lymphoepithelial lesion of salivary glands with malignant changes despite of malignant lymphoma or squamous cell carcinoma the numbers of mast cells are obviously decreased.

Adult↗

PubMed1996

Quantitative analysis of In-111 satumomab pendetide immunoscintigraphy. An aid to visual interpretation of images in patients with suspected carcinomatosis.

The diagnosis of the diffuse intrapertioneal spread of ovarian or colorectal carcinoma (carcinomatosis) can be difficult when based on visual interpretation of immunoscintigraphic images alone. Twenty-nine patients with either colorectal or ovarian cancer were retrospectively evaluated by three technologists for carcinomatosis employing a quantitative analysis technique that compares uptake of In-111 satumomab pendetide (Oncoscint CR/ OV, Cytogen Corp., Princeton, NJ) in a region of interest in the femoral vascular bundle to the uptake in two regions of interest in the lower abdomen, resulting in an uptake ratio (UR). All 29 patients underwent laparotomy after immunoscintigraphy. Of the 29 patients evaluated, 7 had histologically proven carcinomatosis obtained from the laparotomy. Using quantitative analysis, patients who did not have carcinomatosis had a mean uptake ratio of 1.12, and patients with carcinomatosis had a mean uptake ratio of 2.12. The differences between the means of these two groups of patients was statistically significant for all three technologists (P < .05). The results of this study indicate that there is a significant difference in uptake ratios between patients with carcinomatosis and those without it, and that quantitative analysis can be a useful adjunct to visual interpretation.

Abdomen↗

PubMed1997

Application of automatic boundary detection for computerized quantitative analysis of left ventricular regional wall motion by two-dimensional echocardiography.

This study was designed to set up a computer-aided image processing algorithm for boundary detection from two-dimensional echocardiography and to establish a computerized model for quantitative analysis of left ventricular wall motion with the application of automatic boundary detection. The four-chamber view echocardiographic images of seven normal subjects and five patients with acute myocardial infarction were investigated. The main steps of image processing in this algorithm included automatic threshold estimation, contrast stretching, radial search of endocardial boundary, and smoothing of the boundary. The displacements of the left ventricular endocardial contour from end-diastolic to end-systolic frame were measured using a sample point connection model. For analysis of the regional contraction, the left ventricular endocardial contour was divided equally into six segments. The wall motion curves in patients were compared with the normal wall motion pattern established from the normal subjects to identify the segments with normal or abnormal wall motion. The results of this quantitative method were compared with those of qualitative analysis. In the 30 segments of the five patients, quantitative analysis correctly identified nine of the 11 segments with abnormal wall motion diagnosed by qualitative analysis (sensitivity, 82%) and identified 17 of the 19 segments with normal wall motion (specificity, 89%). The positive and negative predictive values of quantitative analysis were 82% (9 of 11) and 89% (17 of 19), respectively, and the diagnostic accuracy was 87% (26 of 30). Our preliminary results suggest that computer-aided boundary detection can be applied to establish an objective and useful model for quantitative analysis of left ventricular regional wall motion.

Adult↗

PubMed1986

Quantitative analysis of thallium-201 uptake and washout before and after transluminal coronary angioplasty.

Transluminal coronary angioplasty has become an important therapeutic modality in the treatment of coronary artery disease. The effects of coronary angioplasty on regional myocardial perfusion have been reported in only a small series of patients, employing subjective analysis of thallium-201 perfusion scintigrams. Thus, we studied 61 patients with quantitative analysis of thallium-201 uptake and washout before and after undergoing angioplasty. Prior to angioplasty, there were 105 areas in 47 patients with abnormal thallium-201 uptake during exercise, with a mean uptake of 49 +/- 1.3%. The uptake of thallium-201 in these same areas increased to 71.3 +/- 1.9% post angioplasty (P less than 0.0001), and 68 (65%) of the areas showing abnormal uptake returned to normal. Abnormalities in washout of thallium-201 before angioplasty were seen more frequently than in uptake (150 vs 105 areas, P less than 0.05), with 8 patients having abnormal washout in the presence of totally normal uptake. Thallium-201 washout in the abnormal areas improved from 16 +/- 2.8 pre angioplasty to -23 +/- 1.8% post angioplasty (P less than 0.001). Normalization resulted in 6 of the 8 patients with exclusively washout abnormality. Residual abnormalities in uptake and/or washout were seen in 53% of the patients, usually in areas with prior myocardial infarction or supplied by a vessel with significant stenosis which did not undergo angioplasty. Improved thallium-201 uptake and washout corresponded to reductions in percent coronary area stenosis (89 +/- 1.0 to 36 +/- 2.0%, P less than 0.001) and transstenotic pressure gradient (42 +/- 3.0 to 9.0 +/- 2.0 mm Hg, P less than 0.001). Thus, quantitative analysis of thallium-201 uptake and washout provided objective evidence for improved myocardial perfusion after coronary angioplasty. Due to a fairly high prevalence of residual perfusion abnormalities after this procedure, optimal assessment of benefits requires quantitative comparison of thallium uptake and washout before and after coronary angioplasty.

Adult↗

PubMed1988

Bone trabecular pattern analysis in Down's syndrome with the use of computed panoramic tomography with a laser scan system. Quantitative analysis with the power spectrum method.

A quantitative analysis of the mandibular bone trabeculae of 44 patients with Down's syndrome and 68 normal persons by means of panoramic tomography was performed with a laser scan system. The results showed that the normal persons exhibited a correlation between the trabecular pattern and aging, whereas the patients with Down's syndrome showed no such correlation. These findings were consistent with geromorphism, which is one of the systemic features of Down's syndrome.

Adult↗