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PubMed2006

Electron-impact and glow-discharge ionization LC-MS analysis of green tea tincture.

A liquid chromatography-particle-beam mass spectrometer (LC-PB/MS) with interchangeable electron-impact (EI) and glow-discharge (GD) ion sources was evaluated for future application in analysis of botanical extracts. In this work a green tea tincture was characterized for a series of catechin components (catechin, epicatechin, epigallocatechin, and epigallocatechin gallate (EGCG)) and caffeine. Special emphasis was given to EGCG and caffeine, because they are important in determining the possible health effects of the green tea. The effects of instrument operating conditions were evaluated for the EI and GD ionization sources to determine their effect on analyte intensities and fragmentation patterns. These studies furnished information about the effects of these conditions in determining possible ionization pathways in the two ion sources. The mass spectra of these compounds obtained with the GD ion source are EI-like in appearance, with clearly identified molecular ions and fragmentation patterns that are easily rationalized. The absolute limits of detection for EGCG and caffeine were, respectively, 11 ng and 0.77 ng for the EI source and 3.2 ng and 0.61 ng for the GD source. The PB/EIMS and PB/GDMS combinations can be operated in a flow-injection mode, wherein the analyte is injected directly into the mobile phase, or coupled to high-performance liquid chromatography (HPLC), enabling LC-MS analysis of complex mixtures. A reversed-phase chromatographic separation of the green tea tincture was performed on a commercial C18 column using a gradient of water (containing 0.1% TFA) and ACN. Quantification of EGCG and caffeine was performed by the standard addition method. The amounts of EGCG and caffeine in the tested green tea tincture were each approximately 14 mg mL-1.

Caffeine↗

PubMed2004

Determination of the effect of calcineurin inhibitors on the rat's immune system after KLH immunisation.

The calcineurin inhibitors cyclosporin A (CsA), tacrolimus (FK506) and pimecrolimus (ASM981) are on the market for the oral treatment of psoriasis and atopic dermatitis and topical treatment of atopic dermatitis, respectively. The effect of these treatments on the immune response was investigated in this study after immunisation of rats with keyhole limpet hemocyanin (KLH). Male rats (10 per group) were orally administered pimecrolimus at 10 or 30 mg/kg/day), tacrolimus at 3 mg/kg/day or CsA at 20 mg/kg/day for 4 weeks. Control animals similarly received the vehicle only. The last five animals per group were immunised and challenged with KLH on days 16 and 24, respectively. Eight days after the last injection, the immune function was investigated by detecting KLH-specific antibodies in the serum and by examination of cell infiltration at the site of the KLH-challenge. In addition, a correlation between functional and structural changes was established by quantification of lymphocyte sub-populations in the blood or residing in lymphatic tissue. In KLH-immunised rats, CsA caused complete suppression of the KLH-specific IgM and IgG production, whereas only IgG production was affected by pimecrolimus at 30 mg/kg/day and more so by tacrolimus at 3 mg/kg/day. Immunophenotyping of lymphocyte sub-populations in spleen and lymph node indicated a decrease in T lymphocytes with pimecrolimus at 30 mg/kg/day, tacrolimus and CsA, whereas these changes were marginal for pimecrolimus at 10 mg/kg/day. Immunophenotyping of peripheral white blood cells (WBC) revealed a decrease in the absolute number of T lymphocytes with all three test items. In comparison with non-immunised animals, a slight increase in absolute numbers of T lymphocytes was observed in KLH-immunised animals treated with pimecrolimus at 10 or 30 mg/kg/day. In conclusion, the ability of the immune system to respond to KLH was not affected by pimecrolimus at 10 mg/kg/day whereas a decrease in immune function was noted in the other groups as follows: pimecrolimus (30 mg/kg/day) < tacrolimus (3 mg/kg/day) < CsA (20 mg/kg/day).

Adjuvants, Immunologic↗

PubMed1997

Quantification of X-ray opacity of the maxillary sinus in the Waters' view.

Plain X-ray filming such as that in the Waters' view is a simple and inexpensive method used in daily practice to briefly evaluate the severity of inflammation of the paranasal sinuses. The maxillary sinus is the largest and simplest in shape among all sinuses and is usually clearly observed on a film in the Waters' view. We attempted to obtain a quantitative index of the X-ray opacity of the maxillary sinus using X-ray films in the Waters' view. A copper wedge was placed to the left side of the subject's face and was filmed simultaneously. The X-ray film was digitized with an image digitizer. The X-ray density of each pixel was then converted to an absolute value for the copper thickness with a medical image processor. The mean pixel value in the region of interest at the maxillary sinus (M(R)) and that at the ipsilateral orbit (O) were determined. The difference, M(R) - O, was found to have a significant correlation with the average visual grading of the severity of inflammation of the maxillary sinus by 10 otolaryngologists. Thus M(R) - O Can serve as an objective measure of the X-ray opacity of the maxillary sinus. The use of this index during the follow-up period is advisable, especially in children, because of greatly reduced amount of X-ray exposure compared with that in computed tomography.

Adult↗

PubMed1997

A tandem solid phase extraction, reversed-phase HPLC method for determining SDZ WAG 994 in dog, monkey and rat blood.

The development and validation of a sensitive and specific HPLC method for SDZ WAG 994 (I) in dog, monkey and rat blood is described. Sample preparation entailed double solid phase extraction (SPE) of I and the internal standard from 0.5 ml of animal blood using a phenyl and propyl sulfonic acid cation exchange column, sequentially. Chromatographic separation was achieved on a YMC Basic C-8 narrowbore HPLC column and the eluates were detected by UV absorption at 266 nm. The method has a linear response up to at least 1800 ng/ml with a limit of quantification of 1 ng/ml across all species. Analysis of 'blinded' quality control dog and monkey blood samples over 3 or 4 days produced median precisions of 2.89 and 4.77%, and median reproducibilities of 4.86 and 10.9%, respectively. Curve fitting of variability estimates indicated that concentration independent error contributed 3-9% of the total method error for the tandem SPE procedure. Extracted endogenous material from blood matrices, several potential metabolites and cyclohexyladenosine were well resolved from the peaks of interest. The stability of I in dog blood stored at -20 degrees C is at least 6 months. The overall absolute and relative recovery of I using the tandem SPE procedure was 85.5 +/- 5.1% and 96.5 +/- 5.0%, respectively. The ruggedness of the method has been demonstrated by multiple analyses, from several toxicokinetic studies, performed by different analysts using comparable instrumentation.

Adenosine↗

PubMed1997

Comparison of two assays for measuring LDL cholesterol.

The purpose of this study was to evaluate the LipiDirect assay (L-LDL) against the Direct LDL immunoseparation method (D-LDL) and beta quantification (BQ-LDL) for measurement of LDL cholesterol (LDL-C) in patients with normo- and hypertriglyceridemia. Samples from 156 patients [triglyceride (Tg) range 0.61-9.95 g/L] were assayed for LDL-C concentrations with the three methods. An additional seven patients with type III hyperlipidemia and 25 paired sera from fasting and nonfasting individuals also were analyzed by the three methods. Both assays displayed excellent precision. The mean LDL-C value from L-LDL was significantly higher than BQ-LDL and D-LDL in normo- and hypertriglyceridemic samples (P < 0.001). The mean absolute bias of L-LDL vs BQ-LDL was 12.7% for Tg < 4 g/L and 30.6% for Tg > or = 4 g/L, compared with 6.2% and 12.5%, respectively, for D-LDL. L-LDL correctly classified only 68% of patients with LDL-C < 1.30 g/L and 57% of patients with LDL-C between 1.30-1.59 g/L as compared with 98% and 93%, respectively, for D-LDL (P < 0.001). In patients with type III hyperlipidemia, L-LDL had a 130% positive bias with BQ-LDL as compared with a 14% negative bias for D-LDL. With all three methods there were no significant differences between samples from fasting and nonfasting individuals. On the basis of these findings, the D-LDL assay appears to be superior to the L-LDL assay.

Cholesterol, LDL↗

PubMed1980

Difficulties in the quantification of asialoglycoprotein receptors on the rat hepatocyte.

Rat hepatocytes were isolated by perfusion with a Ca2+ free solution, followed by a buffer containing Ca2+ and collagenase. They specifically and avidly bind 125I-asialo-orosomucoid. At 4 degrees C, cells in minimal essential medium, incubated in the presence of saturating concentrations of 125I-asialo-orosomucoid, bound 500,000 molecules/cell. Addition of 10% horse serum to the binding reaction reduced the number bound to 200,000. Prewashing of the cells in 1% bovine serum albumin reduced the number of bound molecules by 60%. In all cases, the Kd value was approximately 7 x 10(-9) M. At 37 degrees C, the rate of uptake of 125I-asialo-orosomucoid (approximately 0.1 pmol/min/10(6) cells) is proportionately reduced by the presence of serum or albumin preparatons. Thus, it appears that the absolute number of asialoglycoprotein receptors on the surface of rat hepatocytes is not readily determined in the presence of serum or albumin and is about 500,000/cell.

Animals↗

PubMed2003

Comparison of different kits in the detection of autoantibodies to cardiolipin and beta2glycoprotein 1.

OBJECTIVE: To estimate the performance characteristics of 10 commercial kits and one in-house kit for the detection and quantification of anticardiolipin (aCL) (six kits) and anti-beta2glycoprotein 1 (anti-beta2GP1) (five kits) antibodies, and to evaluate the degree of variability between these different kits. METHODS: We determined the presence of aCL and anti-beta2GP1 IgG and IgM antibodies in 67 sera from 62 patients and reviewed the data separately. Each serum sample was tested with six commercial aCL determination kits and with four commercial and one in-house anti-beta2GP1 determination kit. We then analysed the operating characteristics of each kit (sensitivity, specificity, positive and negative predictive values) and we analysed the absolute and 2 x 2 agreements. RESULTS: The 62 patients included had primary antiphospholipid syndrome (APS) in 10 cases, secondary APS for eight, systemic lupus (SLE) for 23 and other diagnoses for the remaining 21. Operating characteristics differed from one kit to another. Good agreement was found using sensitive aCL determination kit and specific anti-beta2GP1 determination kit. Agreement between kits was medium for IgG aCL. 2 x 2 concordance studies showed a group of three aCL kits which were quite homogenous and showed that all anti-beta2GP1 kits formed quite a homogenous group. CONCLUSION: A high degree of variability still persists for aCL antibody determination posing the question of the qualification of commercial or in-house kits and the question of standardization of results. A better concordance is found for high positive results. Good agreement exists for anti-beta2GP1 kits. aCL determination is still needed and should be complemented by anti-beta2GP1 determination.

Antiphospholipid Syndrome↗

PubMed1999

Quantification of blood--aqueous barrier breakdown after trabeculectomy: pseudoexfoliation versus primary open-angle glaucoma.

PURPOSE: Impairment of the blood-aqueous barrier in unoperated eyes with pseudoexfoliation syndrome has been demonstrated by fluorescein angiography, fluorophotometry, measurement of aqueous flare, and determination of aqueous protein. We performed noninvasive quantification of aqueous flare using the laser flare-cell meter to compare blood-aqueous barrier breakdown after trabeculectomy in eyes with primary open-angle glaucoma (POAG) and in eyes with pseudoexfoliative glaucoma (PEX). METHODS: Twenty eyes with PEX and 20 eyes with POAG were included in the study. Trabeculectomy was performed by two surgeons according to a standard trabeculectomy technique. Intra- and postoperative treatments were identical in both groups. Aqueous flare was quantitatively determined using the laser flare-cell meter FC-1000 (Kowa, Tokyo, Japan) before and 3, 5, 7, and 9 days after trabeculectomy. Absolute flare and difference between post- and preoperative flare values were statistically analyzed using the Mann-Whitney U-Test for independent samples. RESULTS: Before surgery, aqueous flare values were significantly higher in PEX than in POAG. On days 3, 5, 7 and 9 after surgery, flare values were significantly higher in eyes with PEX than in eyes with POAG. Absolute differences between post- and preoperative flare values also were significantly higher in eyes with PEX, but this was not true for percentage values. CONCLUSION: These results show that substantial blood-aqueous barrier breakdown occurs in eyes with PEX after trabeculectomy. These alterations may contribute to early or late complications of trabeculectomy and indicate the need for close postoperative follow-up evaluation in eyes with PEX.

Aged↗

PubMed1997

Mouse/human chimeric IgG1 and IgG4 antibodies directed to the house dust mite allergen Der p 2: use in quantification of allergen specific IgG.

BACKGROUND AND OBJECTIVE: Chimeric mouse/human monoclonal IgG1 and IgG4 antibodies were developed against the house dust mite allergen Der p 2. These chimeric IgG antibodies, hIgG1-Dp2 A and hIgG4-Dp2 A, have the same binding characteristics as the previously reported chimeric hIgE-Dp2 A and are composed of the heavy chain variable domains and light chains of the original murine monoclonal antibody 2B12, whereas the heavy chain constant domains have been replaced by the human IgG1 or IgG4 heavy chain. The expression level of hIgG1-Dp2 A and hIgG4-Dp2 A was 1 and 3.5 microg/mL, respectively. METHODS AND RESULTS: Since all IgG in these culture supernatants is allergen-specific, they are useful reference reagents and enable the calculation of the amount of allergen specific IgG1 and IgG4 antibodies in absolute IgG amounts. The results obtained with two panels of sera from patients in immunotherapeutic treatment were evaluated and compared in Der p 2 IgE, IgG1 and IgG4 RAST and with reversed IgG4 RAST using labelled purified Der p 2. Close agreement between the results for the two IgG4 assays was found. CONCLUSION: With these chimeric reference reagents the quantities of isotype specific antiallergen antibodies can be calculated and compared.

Animals↗

PubMed2004

A novel assay for the quantification of invasion from raft cultures of lung carcinomas.

Assays that conveniently quantify invasion of carcinoma cells in vitro have generally measured the passage of dissociated cells into a matrix. Although these assays have been helpful in identifying relative differences between different carcinoma cell lines or types, the requirement for dissociation overlooks the possible modulation of invasion by cell-cell interactions among carcinoma cells. Described here is a novel assay that quantifies invasion of a matrix placed above intact, multilayered raft cultures of lung carcinoma cell lines A549 and H520. The assay was performed by placing a porous membrane coated with matrix at the air interface of the raft cultures for varying lengths of time, after which the cells invading the matrix were enumerated. The numbers of cells invading increased in a relatively linear fashion from 24 to 72 h, and the absolute numbers within each cell line were reproducible with multiple sets of raft cultures prepared at different times. It was also found that this assay could quantify differences in invasion caused by changes in matrix composition. It is concluded that this assay can reproducibly quantify carcinoma cell invasion from three dimensional raft cultures.

Carcinoma, Non-Small-Cell Lung↗

PubMed2006

Conformational analysis of r207910, a new drug candidate for the treatment of tuberculosis, by a combined NMR and molecular modeling approach.

R207910 is an enantiomeric compound from a new class of antimycobacterial agents, the diarylquinolines [Science; 307:223 (2005)]. As enantiospecific interaction is required for biologic activity, we have undertaken a combined nuclear magnetic resonance and molecular modeling study to gain new insights into its conformation in solution and its absolute configuration. A conformational analysis using a Monte-Carlo method has been performed on each of the four possible stereomers of this compound leading to the identification of their most stable conformation. Additional ab initio calculation was performed with emphasis on the strength of the observed intramolecular hydrogen bond. Simultaneously, a complete structural identification has been carried out by a set of monodimensional and bidimensional (1)H-(13)C-NMR experiments. Determination of inter-proton distances has been achieved by a series of (1)H-(1)H ROESY NMR experiments with different mixing times followed by a volume quantification of the correlations peaks. These experimental data were compared with the theoretical distances obtained from the conformational analysis. The remarkable match shows that R207910 adopts one of the low-energy conformations predicted by molecular modeling and belongs to the (RS, SR) couple of diastereoisomers. A posteriori validation of our approach has been performed by X-ray structure determination that concluded for the RS configuration.

Antitubercular Agents↗

PubMed1990

Analyses of flushing response to alcohol and drinking behavior among shipyard workers and their family members in Hiroshima Prefecture, Japan.

This paper reports on the prevalence of flushing as a subjective symptom, amount of absolute alcohol required to evoke flushing (flushing dose), and relationships among those and drinking frequency or alcohol consumption in Japanese with age of 20 years and above. The percentage of flushers was 68.6% of males and 41.9% of females, non-flushers 18.3%, 11.2%, and unknowns 13.1%, 46.9%, respectively. The percentage of flushers decreased as drinking frequency increased. Flushers drank less than non-flushers among male drinkers, but such a difference in amount of intake between flushers and non-flushers was not found among female drinkers. Drinkers showed a statistically larger flushing dose than non-drinkers. Results of quantification analysis showed correlations between decreasing flushing dose and (a) "less than once a week" drinkers among males and "less than five times per year" drinkers among females, and (b) the initiation of flushing "less than 10 minutes" after ingestion and "upper half of the body" or "whole body" flushing among both males and females.

Adult↗

PubMed2002

Towards a global historical emission inventory for selected PCB congeners--a mass balance approach. 2. Emissions.

Accurate and complete data on the global atmospheric releases (emissions) of individual PCB congeners are essential to study source-receptor relationships and contamination patterns in remote areas, such as the Arctic. Information on the anthropogenic emissions may also be useful for the interpretation of measured levels and patterns of atmospheric PCBs. This study builds upon an accompanying paper, presenting an estimate of the global historical production and consumption of 22 PCB congeners (Breivik K, Sweetman A, Pacyna JM, Jones KC. Towards a global historical emission inventory for selected PCB congeners--a mass balance approach. 1. Global production and consumption. Sci Total Environ, submitted). Here, a dynamic mass balance model is elaborated, parameterised and applied in an attempt to estimate the historical anthropogenic emissions as a direct result of the widespread usage of PCBs for a period of 70 years. This paper presents details of the mass balance approach, along with a discussion of the major uncertainties. It is shown that the diversity of historical usage, disposal and accidental release pathways makes it an extremely difficult task to bridge the gap between consumption and emissions, resulting in an equally complex and diverse true emission pattern. These results may therefore at best represent order-of-magnitude estimates only and the results in absolute terms should be treated with great caution. In spite of these uncertainties, useful information can still be gained. The results suggest that temperature is an extremely important factor controlling both emission amount as well as the emission pattern of PCBs. In particular, the emissions of the more chlorinated (and persistent) PCB congeners appear to be significantly influenced by (uncontrolled) high-temperature sources. As a consequence, it may prove warranted to undertake further measures to avoid that contaminated materials are subject to elevated temperatures and uncontrolled burning. It is furthermore suggested that efforts should be directed towards a better characterisation and quantification of these potentially important release pathways. In addition, alternative approaches to bridge the gap between consumption and emissions in quantitative terms should be considered in order to improve these estimates.

Arctic Regions↗

PubMed2002

An evaluation of a four-channel multiplexed electrospray tandem mass spectrometry for higher throughput quantitative analysis.

A four-channel multiplexed electrospray inlet system (MUX) coupled to a triple quadrupole mass spectrometer was investigated as a higher throughput approach to quantitative analysis. Four discrete samples may be simultaneously analyzed by virtue of a rotating sampler with a concomitant 4-fold increase in analytical throughput. Although absolute sensitivity was reduced using the MUX interface compared with analysis using traditional single electrospray interface, reproducibility of response was shown to be comparable. Source robustness was established for the analysis of both aqueous drug standards and drugs in biological media, and linearity of response for a test compound, diazepam, was demonstrated over 2 orders of magnitude. Analyte-dependent response differences were exhibited between the four channels of the interface, and this led to the overall conclusion that samples to be compared quantitatively must be analyzed through the same sprayer. In addition, each channel must be independently calibrated to afford true quantification. Should a deuterated internal standard be employed, however, quantitative comparisons can be made across channels. An HPLC pumping system providing individual back-pressure regulation to each channel was shown to provide adequate chromatography even in the event of a channel blockage. Furthermore, following multiple injections of biological samples onto the MUX interface, an eluent flow diversion was integrated into the first part of each analytical run. This served to prevent source fouling, and thus, no detrimental effects to response reproducibility or sensitivity were observed.

Clozapine↗

PubMed2003

Quantification of coronary artery calcium with multi-detector row CT: assessing interscan variability with different tube currents pilot study.

PURPOSE: To assess the interscan variability of coronary artery calcium as measured with different tube currents and quantification methods in prospective electrocardiography (ECG)-gated multi-detector row CT. MATERIALS AND METHODS: Thirty-three subjects who were asymptomatic for coronary heart disease underwent prospective ECG-gated, subsecond multi-detector row CT of the heart. Each subject underwent two consecutive CT examinations, the first with a dose of either 40 mAs (n = 18) or 80 mAs (n = 15) and the second with a dose of 150 mAs. Calcium volume and calcium score were calculated. Pearson correlation coefficient was computed between the calcium scores of high- and low-dose examinations. Interscan variability in these measurements (ie, the absolute percentage difference) was compared between the examinations with 40-150 mAs and those with 80-150 mAs by using an independent sample t test. In addition, the interscan variabilities of calcium scores between vessels were evaluated with repeated measures of analysis of variance. The interscan variabilities between calcium score and volume measurement were also compared with paired t tests. RESULTS: Twenty-seven of 33 subjects had coronary artery calcium deposits on both CT scans. Five subjects had no calcium deposit on either scan. One subject had calcium deposits on only one scan. The total calcium score between the high- and low-dose scans was highly correlated (r = 0.98) and was not significantly different (P =.58). The interscan variability of calcium score showed no significant difference with respect to subject (P =.25) or vessel (P =.84). The interscan variability of the calcium volume measurement was significantly lower than that of the calcium score with respect to both the subject (P <.01) and the vessel (P <.01). CONCLUSION: A dose of 40 mAs appears adequate for quantifying coronary artery calcium at multi-detector row CT. Interscan variability of multi-detector row CT is substantially reduced by using the calcium volume method.

Aged↗

PubMed1999

Use of magnetic resonance imaging for in vivo measurements of water content in human brain: method and normal values.

OBJECT: The authors present a quantitative in vivo magnetic resonance (MR) imaging method and propose its use for the accurate assessment of brain water in humans. METHODS: With this technique, a pure T1-weighted image of a selected brain slice in a patient is generated, and the image is subsequently converted to a pure water image by means of an equation derived from a tissue relaxation model. The image intensity in the resulting water map directly yields absolute measures of water expressed in grams of water per gram of tissue at a given anatomical location. The method has been validated previously in a series of phantom experiments and in an infusion model of brain edema in cats. In this report, the authors evaluate the method by using samples of tissue harvested from patients who underwent surgery for brain tumor removal and apply the technique to a series of normal volunteers, providing average regional brain water content (f(w)) values for a range of tissues. Application of the method in pathological conditions such as head trauma, tumor, and hydrocephalus allows quantification of regional or global increases in f(w) that result from edema. CONCLUSIONS: It is now possible to obtain accurate brain water measurements with the anatomical resolution of MR imaging. This permits monitoring of the development and resolution of edema in a variety of clinical circumstances, thus enhancing understanding of the underlying pathophysiological processes.

Adult↗

PubMed2002

The precedence effect for lateralization for the mild sensory neural hearing impaired.

Using dichotic signals presented by headphone, stimulus onset dominance (the precedence effect for lateralization) was investigated for six sensorineural hearing-impaired subjects. Stimuli were based on 2400-Hz lowpass-filtered 5-ms noise bursts. We used the paradigm, as described by Goverts et al. (2000, Hear. Res. 148, 88-94), in which a single noise burst is divided into leading and lagging parts, with opposite lateralization cues (viz. an interaural time delay of 0.2 ms). The occurrence of onset dominance was investigated by measuring the lateral perception of the stimulus ('left' or 'right') with fixed, equal durations of leading and lagging parts, while decreasing the absolute signal level or adding a filtered white noise. The dominance of the leading part was quantified by measuring the lateral perception of the stimulus as a function of the relative duration of the leading (and thus the lagging) part. This was done at about 40 dB sensation level (SL) in quiet and in filtered white noise, at a signal-to-noise ratio resulting in a SL of about 6 dB. Results are compared to normal hearing reference data at various SLs. Hearing-impaired data show a large variance and overall a decreased precedence effect in terms of both occurrence and quantification, which cannot be explained on basis of reduced audibility. Mean performance of the hearing-impaired subjects at 40 dB in quiet was similar to normal hearing performance in masking noise at a signal-to-noise ratio of 0 dB.

Acoustic Stimulation↗

PubMed1994

Choline-containing compounds in human astrocytomas studied by 1H NMR spectroscopy in vivo and in vitro.

We have studied 14 patients with different grades of astrocytomas using 1H NMR spectroscopy in vivo. Typically, astrocytomas exhibited a low N-acetylaspartate peak, a prominent signal from choline group-containing compounds, and lactate in the 1H NMR spectra in vivo. The uncorrected choline/creatine + phosphocreatine peak area ratios were higher in tumors than in normal brain tissue. Absolute concentration of choline-containing compounds (1.74 +/- 0.09 mmol/L) in the normal brain tissue was not different in any grade of astrocytoma, but total creatine concentration in healthy brain (7.49 +/- 0.30 mmol/L) was higher than that in grade IV astrocytomas (4.84 +/- 0.89 mmol/L). Relaxation constants of choline-containing compounds did not differ in tumors from those determined in normal brain. Perchloric acid extracts of biopsy samples from 35 astrocytomas and 13 samples of normal temporal white matter were analyzed with 1H NMR. Total concentration of choline-containing compounds did not differ between controls and any grade of astrocytoma when the quantification was done in vitro. It is interesting that phosphorylcholine concentration was about twofold greater in grade IV astrocytomas than in controls or other grades of astrocytomas. We conclude that high phosphorylcholine in grade IV astrocytomas may be an indicator of degree of malignancy. The proportional changes within the group of choline-containing compounds observed in vitro were not reflected in the NMR properties of choline signal in vivo.

Astrocytoma↗