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PubMed2006

Simultaneous quantitative analysis of metabolites using ion-pair liquid chromatography-electrospray ionization mass spectrometry.

We have developed an analytical method, consisting of ion-pair liquid chromatography coupled to electrospray ionization mass spectrometry (IP-LC-ESI-MS), for the simultaneous quantitative analysis of several key classes of polar metabolites, like nucleotides, coenzyme A esters, sugar nucleotides, and sugar bisphosphates. The use of the ion-pair agent hexylamine and optimization of the pH of the mobile phases were critical parameters in obtaining good retention and peak shapes of many of the above-mentioned polar and acidic metabolites that are impossible to analyze using standard reversed-phase LC/MS. Optimum conditions were found when using a gradient from 5 mM hexylamine in water (pH 6.3) to 90% methanol/10% 10 mM ammonium acetate (pH 8.5). The IP-LC-ESI-MS method was extensively validated by determining the linearity (R2 > 0.995), sensitivity (limit of detection 0.1-1 ng), repeatability, and reproducibility (relative standard deviation <10%). The IP-LC-ESI-MS method was shown to be a useful tool for microbial metabolomics, i.e., the comprehensive quantitative analysis of metabolites in extracts of microorganisms, and for the determination of the energy charge, i.e., the cellular energy status, as an overall quality measure for the sample workup and analytical protocols.

Amines↗
PubMed1987

A quantitative analysis of the metabolic pathways of hepatic glucose synthesis in vivo with 13C-labeled substrates.

A quantitative analysis of the major metabolic pathways of hepatic glucose synthesis in fasted rats was conducted. [2-13C]Acetate was administered intraintestinally into awake fasted rats. 13C NMR and GC-MS analysis were used to quantitate the isotopic enrichments of glutamate, glutamine, lactate, alanine and the newly synthesized liver glucose. By measuring the ratio of carbon atoms in glutamate molecules derived from acetyl-CoA to carbon atoms in the glucose molecule derived from oxaloacetate and gluconeogenic substrates, such as lactate and alanine, the relative activities of the Krebs cycle and gluconeogenesis were quantified. Our results indicate that the percentage of glucose carbons originating by 'metabolic exchange' with the oxaloacetate pool, via the Krebs cycle, is less than 7%.

Acetates↗
PubMed2003

Quantitative analysis of CMV DNA in children the first year after liver transplantation.

CMV infection is a major problem after solid organ transplantation especially in children where primary infection is more common than in adults. Early diagnosis is critical and might be facilitated by quantitative analysis of CMV DNA in blood. In this retrospective study of 18 children who had a liver transplantation 1995-2000, serum samples were analysed by Cobas Amplicor Monitor (Roche). Four patients developed symptomatic CMV infection at a mean time of 4 wk after transplantation. They showed maximum CMV DNA levels in serum of 26 400, 1900, 1300 and 970 copies/mL, respectively. In comparison, CA Monitor was positive, at a low level (415 copies/mL), in one of 11 patients with asymptomatic (4) or latent (7) infection. CMV IgM was detected at significant levels (> or =1/80) in all four patients with symptomatic, and in one with asymptomatic CMV infection. Eight patients were given one or several courses of ganciclovir. Five of these lacked symptoms of CMV disease, and had low (415 copies/mL) or undetectable CMV DNA in serum. The data suggest that quantitative analysis of CMV DNA may be of value in early identification of CMV disease and for avoiding unnecessary antiviral treatment.

Adolescent↗
PubMed2005

Quantitative analysis of activated microglia, ramified and damage of processes in the frontal and temporal lobes of chronic schizophrenics.

Under pathological conditions, microglial cells undergo activation, which is manifested by the expression of histocompatibility locus antigens class II (HLA II) on their surface as well as by proliferation and varied morphological forms. In schizophrenia, characterised by an essential role played by immunological mechanisms, quantitative analysis of activated microglia -- with well-developed ramification (RM), degenerative traits and damaged processes (from their shortening to their complete lack) (DM) -- may contribute to better understanding of schizophrenia etiopathogenesis. Quantitative analysis was performed on slices derived from the frontal and temporal lobes of 9 brains of schizophrenics and 6 control brains. The nonparametric Mann-Whitney U test was used to assess quantitative differences in the distribution of microglia in these regions of the brain. Statistical analyses were performed with STATISTICA 6.5 Programme. In both structures of the brain, the number of activated microglial cells was higher in schizophrenic brains than in control brains. Except for the first layer of the cerebral cortex with the same amounts of RM and DM, the number of DM cells in the remaining regions was several-fold higher than that of RM cells. It is most likely that disturbances in calcium metabolism and energetic balance as well as antibodies produced in the course of schizophrenia are the agents able to trigger a cascade transforming RM into DM. Quantitative differences in RM and DM, observed between the studied structures and cortical regions, could depend not only on functioning of inter-neuronal and inter-structural links. Our study suggests a pivotal role of microglial cells in repair processes and/or etiopathogenesis of schizophrenia and indicates that they undergo substantial damage in the course of chronic schizophrenia.

Adult↗
PubMed2004

[Quantitative analysis of active substances in St. John's wort (Hypericum perforatum L.) by the high performance liquid chromatography method].

The flavonoids (rutin, quercetin, and isoquercetin) and hypericin are the main active substances of St. John's wort (Hypericum perforatum). They support regeneration of human body cells, provide disinfection, and act as antidepressant, antiviral, and anti-inflammation tools. Such large spectrum of the applicable functions depends on the quantity of each substance. The objective of this paper is to determine the regularities of the quantitative variation of rutin, quercetin, isoquercetin and hypericin in flowers and leaves of St. John's wort in different habitats and different plant development phases. Plant material for the quantitative analysis was collected in 1998-1999. The high performance liquid chromatography (HPLC) was applied for the quantitative analysis of the active substances in St. John's wort. The flavonoids (rutin, quercetin, and isoquercetin) were identified under the UV waves of 254 nm, and hypericin - under the waves of 590 nm. Larger quantities of rutin were found in leaves, while those of quercetin, isoquercetin and hypericin - in flowers of St. John's wort. The highest accumulation of active substances was observed during the development of flowering buds and in flowering time. The quantitative variation of active substances in different habitats allows the selection of the best plant samples for their cultivation and conservation in field collections.

Anthracenes↗
PubMed1993

A quantitative analysis of the microglial cell reaction in central primary sensory projection territories following peripheral nerve injury in the adult rat.

The time course of the microglial cell reaction in central nervous system primary sensory projection territories has been examined following peripheral nerve injury in the adult rat using qualitative and quantitative analysis of immunoreactivity with the monoclonal antibody OX-42, which recognises the complement receptor CR3. The regions examined included the gracile nucleus, the column of Clarke and the spinal cord dorsal horn (superficial and deep laminae separately) after unilateral sciatic nerve transection, and the spinal trigeminal nucleus following unilateral infraorbital nerve transection. In all territories examined a qualitative increase in OX-42 immunoreactivity was observed 24 h postlesion. Further, quantitative analysis revealed an exponential development of the OX-42 immunoreactivity, with a peak at one week postlesion, thereafter showing a slow exponential decline. Our results show that the signal (or signals) that induces the microglial cell response in primary sensory projection territories is rapid in comparison to previously described central degenerative changes following peripheral nerve lesions (transganglionic degeneration). These findings are compatible with the hypothesis that activated microglia play a pathogenetic role in the development of transganglionic degeneration.

Afferent Pathways↗
PubMed2002

Quantitative analysis of undefined mixtures - "fishing net" algorithm.

An approach for quantitative analysis of mixtures with unknown individual responses of the components is discussed. Although it is based on a resolution of overlapping bands technique, the main emphasis is not given to the computational facets of curve fitting. A logical procedure is described, allowing estimation of the unknown concentrations in the mixture, and both the number of overlapping bands and their assignment to the components in the solution to be determined automatically. A general conclusion about the precision of the method cannot be defined, because it depends on the extent of overlapping of the individual spectra of the components and their complexity. Using this procedure a complicated three-component acid-base equilibrium of a halochromic dye in solution is studied.

Journal Article↗
PubMed1998

Quantitative analysis of gas losses and gains in the middle ear.

Quantitative analysis of the amount of gas entering and leaving the middle ear (ME) was performed in patients with central perforation or with ventilating tubes. Patients were divided into a 'balanced pressure group' (BP) where pressure remained close to atmospheric throughout the measuring period and an 'unbalanced pressure group' (UBP) where pressure decreased continuously throughout measurements. The rate of gas gain was 41.0 +/- 19.9 microl/h (mean +/- SD, n = 17) in the BP group, significantly higher than in the UBP group (21.4 +/- 9.6 microl/h, n = 8). The rate of gas loss was 34.8 +/- 17.7 and 36.1 +/- 15.9 microl/h in the BP and UBP groups, respectively. Deglutition frequency was 27 +/- 13.4 deglutition/h in the BP group, significantly higher than the deglutition frequency of the UBP group (16 +/- 8.9 deglutition/h). It seems that the amount of gas entering the ME per deglutition is rather stable and does not change significantly with ME pressure level. Negative ME pressure may result from decreased gas gain rate due to increased intervals between deglutitions and loss of interdependence between the rate of gas entering and leaving the ME.

Adolescent↗
PubMed1989

Quantitative analysis of anabolics on thin-layer chromatographic plates using image analysis techniques.

A new detection system is introduced for the quantitative analysis of thin-layer chromatographic plates, which is based on a relatively simple, cheap but advanced image analysis system. Both one- and two-dimensional plates can be analysed. Recording and analysis can also be performed from photographs or even slides. Applications are shown for a number of samples containing anabolic compounds.

Anabolic Agents↗
PubMed2005

Quantitative analysis in nanoliter wells by prefilling of wells using electrospray deposition followed by sample introduction with a coverslip method.

In contrast to performing assays on a substrate using immobilization techniques, wet analysis in nanoliter-sized wells allows quantitative monitoring of enzyme-based reactions by measuring luminescence with time. However, a suitable dispensing method is required to accurately deposit stabilized enzyme solutions into nanoliter wells in such a manner that the enzyme activities are preserved prior to and during measurements. Furthermore, an efficient method is required to add sample liquid to these wells in such a manner that evaporation of assay liquid is completely prevented during sample introduction and monitoring. A powerful methodology is presented in this paper allowing quantitative analysis of enzyme-based reactions in identical nanoliter volumes on-chip. In a first step, picoliter amounts of protein solutions are deposited as uniform dry dots into wells using our reported electrospraying technique (Moerman, R.; Frank, J.; Marijnissen, J. C. M.; Schalkhammer, T. G. M.; van Dedem, G. W. K. Anal. Chem. 2001, 73, 2183-2189.). The silicon chips are then stored at temperatures as low as -80 degrees C. At the time of analysis, a sample solution is slid into the wells using a coverslip. With the edge of the coverslip, sample solution is pushed across the wells at a speed of 1.5-2.5 cm/s to prevent carryover of reagents to neighboring wells. Evaporation of assay liquid from the wells is prevented because the coverslip seals the wells and "bonds" to the chip by adhesion forces. Electrospraying appears to be an excellent method to deposit enzyme solutions containing up to 20% (w/v) of trehalose without being hampered by clogging of the capillary or splashing of droplets. After being sprayed on-chip (silicon nitride), the enzymes pyruvate kinase and lactate dehydrogenase remained stable for a period of 1.5-2 months at a storage temperature of -20 degrees C. The coverslip method completely prevented evaporation for minutes up to hours allowing monitoring of enzyme-based reactions in arrays of nanoliter wells.

Enzyme Stability↗
PubMed2003

Quantitative analysis of polyethylene blends by Fourier transform infrared spectroscopy.

The quantitative analysis of binary polyethylene (PE) blends by Fourier transform infrared (FT-IR) spectroscopy has been achieved based on the ratio of two absorbance peaks in an FT-IR spectrum. The frequencies for the absorbance ratio are selected based on structural entities of the PE components in the blend. A linear relationship between the absorbance ratio and the blend composition was found to exist if one of the absorbance peaks is distinct to one of the components and the other peak is common to both components. It was also found that any peak resulting from short-chain branching in copolymers (such as linear low-density polyethylene (LLDPE) or metallocene-catalyzed LLDPE (mLLDPE)), is suitable for use as the peak that is designated as being distinct to that component. In order to optimize the linearity of the equation, however, the selection of the second common peak is the most important and depends on the blend system studied. Indeed, under certain circumstances peaks that are not spectrally distinct can be used successfully to apply the method. The method exhibits potential for the routine analysis of PE blends that have been calibrated prior to its application.

Complex Mixtures↗
PubMedDate not supplied

Evaluation of laryngeal muscle function by quantitative analysis of the EMG interference pattern.

A computerized method for quantitative analysis of the EMG interference pattern was tested in the cricothyroid and thyroarytenoid muscles with the purpose of evaluating its usefulness for clinical purposes. In a normal male subject the mean amplitude and the number of turns/s were extracted from the EMG signal of sustained chest register phonations, with systematic variation of vocal pitch and intensity. In the cricothyroid, as well as the thyroarytenoid muscle, there was a considerable increase in mean amplitude and turns/s with both increased pitch and increased intensity. Pitch variation was the most effective way to induce changes in turns and amplitude levels in both muscles. In contrast to results from studies of larger muscles, the increase in both amplitude and turns was proportional to muscle force also at the highest loads.

Electromyography↗
PubMed1991

Quantitative analysis of laryngeal EMG in normal subjects.

A method for quantitative analysis of the electromyographic interference pattern called "turns/amplitude analysis" was carried out with recordings from the cricothyroid and thyroarytenoid muscles of 12 normal subjects, 6 males and 6 females. The purpose was to investigate how the two muscles vary contraction force in relation to variations in pitch and voice intensity. Sustained phonations with systematic variation of pitch and intensity were analysed. The contraction force, in terms of turns and amplitude, increased with increasing pitch in both the cricothyroid and thyroarytenoid. More variability in contraction activity as a function of intensity was noted in the cricothyroid than in the thyroarytenoid. The increase in turns and amplitude in the thyroarytenoid with increasing pitch was highly significant, while little effect was seen of intensity variation. No great differences between males and females were noted.

Adult↗
PubMed1999

[Quantitative analysis of butachlor, oxadiazon and simetryn by gas chromatography].

The quantitative analysis of the ingredients in 26% B-O-S (butachlor, oxadiazon and simetryn) emulsion by gas chromatographic method was carried out with a 5% SE-30 on Chromosorb AW DMCS, 2 m x 3 mm i.d., glass column at column temperature of 210 degrees C and detector temperature of 230 degrees C. The internal standard is di-n-butyl sebacate. The retentions of simetryn, internal standard, butachlor and oxadiazon were 6.5, 8.3, 9.9 and 11.9 min respectively. This method has a recovery of 98.62%-100.77% and the coefficients of variation of this analysis of butachlor, oxadiazon and simetryn were 0.46%, 0.32% and 0.57% respectively. All coefficients of linear correlation were higher than 0.999.

English Abstract↗
PubMedDate not supplied

[A quantitative analysis of nucleolar organizer regions (NORs) in renal adenocarcinoma].

A quantitative analysis of nucleolar organizer regions (NORs) in renal adenocarcinoma is proposed. The NORs have been evaluated on paraffin sections by a silver staining methods. A series of 19 renal adenocarcinoma is tested. A significant statistical difference (P less than 0.001) is found between normal and neoplastic tubules and between different stages of neoplasia. The authors suggest that this method if supported by authors date, may be a new prognostic index.

Adult↗
PubMed1987

[Automatic quantitative analysis of myocardial tomography thallium-201 scintigraphy].

An automatic and quantitative analysis method for tomographic scintigraphy was applied to 104 patients with myocardial infarction (anterior 37, inferior 67, lateral 20, involving 2 territories in some cases). All patients underwent exercise and redistribution scintigraphy and coronary arteriography which served as reference. Two types of tomographic sections were used: 2 short axis sections exploring the left ventricle at different levels, and 1 apical section at a right angle with the first ones. A circumferential analysis program studied the isotopic activity of each section and drew an activity profile curve which was compared with those obtained in normal subjects. Exercise curves proved superior to redistribution and wash-out curves and were therefore used exclusively. Two sectoring methods for territories with infarcts were defined: conventional sectoring, which gives a 90 degrees angle to the anterior region and a 180 degrees angle to the inferior lateral region, and real sectoring established from the scintigraphic abnormalities observed in patients whose infarction was not accompanied by significant lesions in other territories. Real sectoring divides the territory into two regions (anterior and infero-lateral) and determines the extension territory and the territories specific to each necrotic region. The sensitivity and specificity of these two methods for the diagnosis of necrosis and the detection of a significant abnormality (greater than 70% stenosis, or necrosis) in a territory other than the one with infarct were compared. In the diagnosis of infarction: conventional sectoring sensitivity 92%, specificity 46% for anterior infarcts, 94% and 25% for inferior and lateral infarcts; real sectoring 94% and 63% respectively for anterior infarcts, 92% and 68% for inferior infarcts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Quantitative analysis of technetium 99m 2-methoxyisobutyl isonitrile single-photon emission computed tomography and isosorbide dinitrate infusion in assessment of myocardial viability before and after revascularization.

BACKGROUND: Assessment of viable myocardium in territories of hypoperfused myocardium is important for predicting functional recovery after revascularization. This study was designed to evaluate quantitative analysis of 99mTc-labeled 2-methoxyisobutyl isonitrile (MIBI) myocardial perfusion imaging combined with isosorbide dinitrate (ISDN) infusion to detect myocardial viability in patients with chronic coronary artery disease before and after revascularization. METHODS AND RESULTS: Twenty-seven consecutive patients with previous myocardial infarction and left ventricular dysfunction (left ventricular ejection fraction 35.2% +/- 13.5%) referred for coronary artery bypass (CABG) were studied with 99mTc-labeled MIBI single-photon emission computed tomography at rest and during ISDN infusion before CABG followed by resting imaging after CABG. Quantitative analysis was performed with circumferential profiles. Left ventricular function (global and regional) was assessed by radionuclide ventriculography before and after CABG. Out of 212 abnormal perfusion segments with resting 99mTc-labeled MIBI SPECT, 99 segments (47%) showed improved uptake of 99mTc-labeled MIBI during ISDN infusion. The mean ratio of myocardial uptake was 0.58 +/- 0.25 (resting 0.53 +/- 0.23; p < 0.05). After CABG, of 212 segments with hypoperfusion, 108 segments (51%; p > 0.05 vs ISDN) showed improved uptake of 99mTc-labeled MIBI. The mean ratio of myocardial uptake was 0.60 +/- 0.26 (resting 0.53 +/- 0.23; p < 0.05). The concordance between the improvement of post-CABG wall motion and that of pre-CABG ISDN perfusion imaging was 83%, between the improvement of wall motion and perfusion imaging after CABG 94%, and between the improvement of pre-CABG ISDN and post-CABG perfusion imaging 83%, respectively. CONCLUSION: ISDN infusion can improve the uptake of 99mTc-labeled MIBI in hypoperfused myocardium and increase the efficiency of 99mTc-labeled MIBI in the detection of viable myocardium in patients with previous myocardial infarction and left ventricular dysfunction.

Coronary Artery Bypass↗
PubMed1989

A comparison between visual and quantitative analysis in a prospective evaluation of labelled 111In leucocyte imaging in vascular infection.

In a continuing evaluation of 111In-oxine labelled leucocyte imaging in vascular surgery, we have studied 16 patients with a clinical diagnosis of possible vascular graft infection. We have evaluated both visual and semi-quantitative analysis of the images obtained and have interpreted these in the light of the subsequent clinical outcome. Full length or multifocal uptake was seen in six patients, all of whom eventually required graft excision with two limbs surviving, and one death. These patients had a significantly higher uptake ratio (median = 3.26) than those with either localized (median = 1.12; p = 0.0027) or negative images (median = 0.72; p = 0.0003). Of four patients showing localized uptake only, one required amputation for continuing sepsis. Six patients had negative images, and had normal DSA and CT scans. Uptake ratios could not distinguish between those with localized images and those with negative images. Computer generated vertical profiles aided separation of patients with presumed localized and negative images. Semi-quantitative analysis has proved to be a reliable method which should allow a more direct comparison of the efficacy of various investigative techniques and of the results of therapy, independent of intra-observer subjective bias.

Aged↗