bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental allergic encephalomyelitis in non‐human primates: mri and mrs may predict the type of brain damage
Authors: Richards T. L. , Petersen K. , Heide A. C. , Cluff J. , Alvord E. C. , Rose L. M. , Peterson J. , Cosgrove S. , Petersen R.
Published: March 2007

Volume‐localized proton spectroscopy and T2‐weighted MRI were performed on 23 monkeys with experimental allergic encephalomyelitis (EAE). The purpose of this study was to determine the relationships between temporal changes in lesion activity (measured on T2‐weighted MRI), MRS [N‐acetyl aspartate (NAA), creatine (CR), choline (CHO)], and the histologic definition of disease determined post‐mortem. Animals were scanned in the same areas of the brain once a week before and after sensitization to myelin basic protein (BP). Histologic lesion types were predicted by a combination of preceding MRI and MRS measurements. Acutely fatal EAE lesions were large and monophasic as visualized by MRI, and increased CHO (p<0.02, n=16) and CHO/CR ratio (p<0.001, n = 16) were detected by MRS at disease onset. Chronic EAE lesions were preceded by multiple inflammatory attacks as visualized by MRI and consistently low levels of NAA (p<0.02, n = 13) and NAA/CR (p<0.01, n = 13) which occurred after the initial attack. MRI negative brain regions (from animals that were sensitized to BP) were associated with low CHO/CR (p<0.1, n = 5). The temporal correlation of MRI lesion activity and absolute MRS proton metabolites shows promise for predicting the subsequent duration and histologic type of lesions in EAE in non‐human primates.
31P nmr spectroscopy studies of phopholipid metabolism in human melanoma xenograft lines differing in rate of tumour cell proliferation
Authors: Lyng Heidi , Olsen Dag R. , Rofstad Einar K. , Petersen Steffen B.
Published: March 2007

The concentration of phospholipid metabolites in tumours has been hypothesized to be related to rate of cell membrane turnover and may reflect rate of cell proliferation. The purpose of the study reported here was to investigate whether 31P NMR resonance ratios involving the phosphomonoester (PME) or phosphodiester (PDE) resonance are correlated to fraction of cells in S‐phase or volume‐doubling time in experimental tumours. Four human melanoma xenograft lines (BEX‐t, HUX‐t, SAX‐t, WIX‐t) were included in the study. The tumours were grown subcutaneously in male BALB/c‐nu/nu mice. 31P NMR spectroscopy was performed at a magnetic field strength of 4.7 T. Fraction of cells in S‐phase was measured by flow cytometry. Tumour volume‐doubling time was determined by Gompertzian analysis of volumetric growth data. BEX‐t and SAX‐t tumours differed in fraction of cells in S‐phase and volume‐doubling time, but showed similar 31P NMR resonance ratios. BEX‐t and WIX‐t tumours showed significantly different 31P NMR resonance ratios but similar fractions of cells in S‐phase. The 31P NMR resonance ratios were significantly different for small and large HUX‐t tumours even though fraction of cells in S‐phase and volume‐doubling time did not differ with tumour volume. None of the 31P NMR resonance ratios showed significant increase with increasing fraction of cells in S‐phase or significant decrease with increasing tumour volume‐doubling time across the four xenograft lines. Consequently, the PME and PDE resonances of 31P NMR spectra recorded in vivo are probably of limited value in assessment of rate of cell proliferation in tumours and hence also in prediction of tumour treatment resistance caused by rapid cell proliferation.
Chemotherapy‐associated changes in 31P MRS spectra of sera from patients with multiple myeloma
Authors: Kuliszkiewicz‐Janus M. , Baczynski S.
Published: March 2007

31P NMR spectra were obtained from sera of 22 healthy volunteers and 20 patients with multiple myeloma at the time of diagnosis and repeated up to five times during therapy. All spectra consisted of a Pi peak (used as a reference peak) and two peaks from phospholipids (PL): one peak due to phosphatidylethanolamine and sphingomyelin (PE + SM) and a second peak due to phosphatidylcholine (PC). Prior to therapy, peak intensities of the phospholipids were low relative to Pi. During therapy leading to remission, the resonance from PL progressively increased to approximate the spectral pattern seen in normal sera. By contrast, in non‐responders an opposite trend was noted: the intensities of the phospholipid peaks became progressively reduced or remained unchanged. Long‐term follow‐up studies showed a good correlation between this 31P MRS evaluation of sera and the response of the disease to the therapy. In addition to the correlation with tumor response, our studies also show significant correlations between area, intensities of peaks of PE + SM, PC, and the concentrations of high‐density lipoprotein (HDL) (correlation coefficients 0.46, 0.43, 0.59, respectively; p<0.001). We found that the concentration of HDL in serum of patients with multiple myeloma was significantly reduced. In individuals responding to therapy HDL levels increased to the point where there were no statistically significant differences between them and healthy volunteers. In patients not responding to therapy, HDL concentration did not increase. In summary, analysis of plasma lipids by MRS offers a convenient method for establishing a blood lipid profile in patients with haematological malignant disease and offers yet another modality for assessing patient response to therapy in multiple myeloma.
In vivo quantitation of metabolite concentrations in the brain by means of proton MRS
Authors: Henriksen Ole
Published: March 2007

MRS offers unique possibilities for non‐invasive studies of biochemistry in the human brain in vivo. A growing body of evidence suggests that proton MRS may contribute to the clinical evaluation of a number of pathologies including ischaemia, tumours, epilepsy, metabolic and neuropaediatric disorders. In most cases results are expressed as ratios between metabolite signals obtained at certain experimental conditions. Presenting the results as metabolite signal ratios may lead to misinterpretation because such alterations can be due to changes in the content of either one of the metabolites or both, or may simply be due to changes in relaxation behaviour. Absolute quantitation of metabolite concentrations is therefore warranted. A number of studies using single volume proton MRS indicate that absolute quantitation of metabolite concentration is possible with respect to N‐acetyl aspartate (NAA), total creatine, choline containing compounds, (Cho) and inositols (Ins). Internal standards (unsaturated water signal) as well as external standards have been used for signal calibration. Quality control with respect to signal linearity with concentration or with size of selected volume, selection efficiency, outer volume depression and signal contamination is essential for validation of the measurements. Furthermore, corrections for the influence of relaxation behaviour are necessary. The results published so far indicate that the concentrations of NAA, total creatine, Cho and Ins in mmoles (kg wet weight)−1 range between 8.2 and 17.2, (mean 10.2), 5.9 and 11.6 (mean 7.2), 1.1 and 2.0 (mean 1.5) and 3.9 and 8.1 (mean 6.1), respectively. So far only a limited number of clinical studies has been published including studies of acute stroke, multiple sclerosis and Alzheimer's disease. The results are promising and encourage further exploitation of the utility of quantitative proton MRS in clinical practise.
The design of macrocyclic ligands for monitoring magnesium in tissue by 31P NMR
Authors: Haveren Jacco Van , Deleon Linda , Ramasamy Ravichandran , Westrenen Jeroen Van , Dean Sherry A.
Published: March 2007

A series of ligands based upon 1,4,7‐triazacyclononane, containing variable numbers of acetate vs methylene‐phosphonate ester or methylenephosphinate sidechains, has been synthesized and characterized as possible 31P NMR probes for monitoring [Mg2+ ]free. The diacetate monophosphinate and diacetate monophosphonate ester mixed ligands proved to have conditional (dissociation) constants at pH 7.4 in an appropriate range for measuring typical levels of intracellular [Mg2+ ]free and binding selectivities for Mg2+ over Ca2+ that ranged from 1.4 to 6.8. The 31P resonances of these ligands were well downfield of typical tissue phosphate metabolite resonances, and addition of Mg2+ to any one of these ligands resulted in well‐resolved resonances for HL and MgL (where L = ligand), in slow chemical exchange. The chemical shift differences between the HL and MgL species varied from 2.1 to 2.6 ppm for three different ligands. The conditional Mg2+‐L binding constants were sensitive to pH in the physiological range, due to protonation of a single macrocyclic nitrogen at high pH (log K1 values ranged from 10 to 12). However, given conditions that allow an independent assessment of pH (i.e., from the 31P chemical shift of Pi), we show that accurate KD values can be estimated from the known thermodynamic stability constants (KMgL) and ligand protonation constants (K1). This makes these ligands potentially useful for monitoring [Mg2+ ]free by 31P NMR over a variety of solution conditions, even during conditions when the pH may be changing.
A fast method for in vivo lactate imaging
Authors: Reese T. , Norris D. G. , Leibfritz D.
Published: March 2007

A robust method for fast lactate imaging is presented using a combination of a lactate editing sequence and a one‐shot imaging experiment. The lactate editing method is based on manipulation of the phase of the lactate CH3 signal via J‐modulation. This is applied as a preparation experiment to the U‐FLARE imaging sequence. Phantom experiments are presented in which the quality of water and lipid suppression is established. Edited lactate images with a spatial resolution of 3 m̈L and total measuring time of 15.8 min are shown. These were obtained from a hemispherical ischemia in the gerbil brain. The images are compared with diffusion‐weighted water images.
T1 and T2 relaxation times of the major 1H‐containing metabolites in rat brain after focal ischemia
Authors: Toorn Annette Van Der , Dijkhuizen Rick M. , Tulleken Cees A. F. , Nicolay Klaas
Published: March 2007

The relaxation properties of water and metabolites were measured in rat brain following the occlusion of the middle cerebral artery (MCA) with localized 1H MRS. The PRESS sequence was employed to select volumes of 39 m̈L in the ischemic and the contralateral hemisphere. T1 and T2 relaxation times and peak intensities of water, choline containing compounds (Cho), creatine and phosphocreatine (Cre) and N‐acetyl aspartate (NAA) in both hemispheres were determined at 3‐6 h, 1 day and 3 or 4 days after occlusion. Lactate in the ischemic hemisphere was also quantified. The relaxation properties and peak intensities of NAA, Cre and Cho remained unchanged in the ischemic volume during the first 3‐6 h of ischemia as compared to the contralateral volume. Water T1 was slightly increased in the ischemic volume. After 24 h the T1 and T2 of water and Cre and the T1 of Cho had increased significantly in the ischemic volume, while the peak intensities of Cho, Cre and NAA were reduced. It appears therefore that tissue changes which occur in the early phase of ischemia have no significant effects on the relaxation behaviour of the metabolites. However, ischemic brain damage affects the relaxation behaviour and concentration of the metabolites and water at later stages.
Characteristic metabolic profiles revealed by 1H NMR spectroscopy for three types of human brain and nervous system tumours
Authors: Florian Catarina L. , Preece Nicholas E. , Bhakoo Kishore K. , Williams Stephen R. , Noble Mark
Published: March 2007

Cell culture techniques, high‐resolution in vitro 1H NMR spectroscopy, and chromatographic analyses were used to compare the properties of three types of human brain and nervous system tumours. Cell lines were immunocytochemically characterized at all stages in culture with specific antibodies. Intracellular metabolites present in cell extracts were analysed by 1H NMR spectroscopy and by high performance liquid chromatography (HPLC). The spectra from meningiomas, neuroblastomas, and glioblastomas displayed, in addition to similarities — including the presence of signals from leucine, isoleucine, valine, threonine, lactate, acetate, glutamate, choline‐containing compounds and glycine — certain distinguishing metabolic features. Spectra from meningiomas featured relatively high signals from alanine. Intense signals from creatine were present in neuroblastoma spectra, while in spectra from glioblastoma they were not detectable. We found statistically significant differences by 1H NMR spectroscopy in the amounts of alanine, glutamate, creatine, phosphorylcholine and threonine among the types of tumours examined. HPLC determinations confirmed that there were also other metabolites specific to a type of tumour, such as taurine, γ‐aminobutyric acid, and serine. We suggest that these findings have potential relevance for the development of non‐invasive diagnosis of tumour lineage by 1H NMR spectroscopy in vivo.
Signal profile measurements for evaluation of the volume‐selection performance of ISIS
Authors: Ljungberg Maria , Starck Göran , Forssell‐Aronsson Eva , Alpsten Magne , Ekholm Sven
Published: March 2007

High‐resolution signal profiles obtained with a test phantom were used in this study to evaluate the volume‐selection performance of an implementation of ISIS (Image Selected In vivo Spectroscopy). The phantom simulated the brain with regard to volume and loading of coil. A remotely controlled, movable signal source inside the phantom was filled with orthophosphoric acid. Signal profiles of the volume of interest (VOI) were measured in three perpendicular directions. Special interest was focused on the transition zones, the position of the profiles, and the effects of off‐resonance and T1 smearing. The transition zones were on average 5.6 mm wide and the full width at half maximum (FWHM) was 35 mm for a VOI of 40 × 40 times; 40 mm3. The positions of the centre of the signal profiles were x = 3.2, y=‐0.7 and z=3.3mm off‐centre. The deviation of the volume position could be explained by off‐resonance effects during imaging and spectroscopy. These data illustrate the importance of detailed knowledge of the volume‐selection performance when attempting precision measurements using image‐guided in vivo MRS.
The application of porous‐media theory to the investigation of time‐dependent diffusion in in vivo systems
Authors: Helmer Karl G. , Dardzinski Bernard J. , Sotak Christopher H.
Published: March 2007

Recent developments in solid‐boundary porous‐media theory have shown that useful structural information can be extracted from the time‐dependent diffusion coefficient, D(t), of the fluid filling the interstitial space. This theoretical framework provides a basis from which to understand the results from diffusion experiments performed in other types of systems (e.g. biological). Structural information about porous media can be obtained from the short‐time behavior of D(t) in the form of the ratio of the surface area to pore volume, S/V. The long‐time behavior of D(t) in porous media provides an indirect measure of the macroscopic structure. In this case, the longtime diffusion coefficient, Deff, reflects the tortuosity, T, of the medium; a property of both the connectivity of the diffusion paths and the volume fraction of the sample. Measurements of D(t) were performed in RIF‐1 tumors, using both spectroscopy and imaging, and the data were used to calculate S/V and T. The results were compared with histological sections in order to correlate S/V and T with differences in tissue structure (i.e. necrotic vs non‐necrotic tumor tissue). Based on spectroscopic measurements, there is a trend towards decreasing S/V and T with increasing tumor volume, consistent with the interpretation that water in necrotic tissue is experiencing relatively fewer restricting barriers (as compared to non‐necrotic tumor tissue). Based on D(t) maps generated from RIF‐1 tumors, Deff, and hence T appears to be much more sensitive than S/V in differentiating between necrotic and non‐necrotic tissue. In addition to characterizing diseased tissue, S/V and particularly T appear to be sensitive to structural changes that would accompany tumor treatment and should therefore provide a useful tool for monitoring the progress of therapeutic interventions.
Molecular diffusion, tissue microdynamics and microstructure
Authors: Bihan Denis Le
Published: March 2007

Diffusion NMR is the only method available today that noninvasively provides information on molecular displacements over distances comparable to cell dimensions. This information can be used to infer tissue microstructure and microdynamics. However, data may be fairly difficult to interpret in biological tissues which differ markedly from the theoretical “infinite isotrope medium”, as many factors may affect the NMR signal. The object of this paper is to analyze the expected effects of temperature, restriction, hindrance, membrane permeability, anisotropy and tissue inhomogeneity on the diffusion measurements. Powerful methods, such as q‐space imaging, diffusion tensor imaging and diffusion spectroscopy of metabolites further enhance the specificity of the information obtained from diffusion NMR experiments.
Isolation and identification of the five major sesquiterpene hydrocarbons of ginger
Authors: Van Beek Teris A. , Lelyveld Gerrit P.
Published: March 2007

Forty‐eight different ginger oils from nine countries spanning four continents have been investigated by dual capillary gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). All oils were found to contain the same five major sesquiterpene hydrocarbons. Two of them were isolated in one step from an Indian oil by an efficient reversed phase high performance liquid chromatographic (RP‐HPLC) separation. The other three were isolated by a combination of RP‐HPLC and preparative capillary GC. They were identified by UV, MS, 1H NMR and 13C NMR as α‐zingiberene (1), β‐bisabolene (2), (E,E)‐α‐farnesene (3), β‐sesquiphellandrene (4) and ar‐curcumene (5). The reported absence of some of these compounds in earlier studies could in many cases be explained by unsatisfactory separations, misidentifications and confusion in the nomenclature.
A blind comparison of simple bench‐top bioassays and human tumour cell cytotoxicities as antitumor prescreens
Authors: Anderson J. E. , Goetz C. M. , McLaughlin J. L. , Suffness M.
Published: March 2007

Simple bench‐top bioassays involving brine shrimp lethality, Lemna frond proliferation, and the inhibition of crown gall tumours on potato discs, as well as the human tumour cell lines A‐549 lung carcinoma, MCF‐7 breast carcinoma and HT‐29 colon adenocarcinoma, were compared for their accuracy to detect known in vivo (P‐388) active antitumour agents supplied by the National Cancer Institute. The potato disc assay was the best and showed excellent correlation to in vivo activity (p=0.008). The brine shrimp assay (p = 0.033) proved to be superior or equally as accurate as the in vitro human solid tumour cell lines (p = 0.033‐0.334). The Lemna assay (p = 0.708) showed the poorest correlation. The brine shrimp and potato disc assays are suggested as convenient in‐house prescreens to existing cytotoxicity or antitumour assays.
Analysis and distribution of swainsonine and related polyhydroxyindolizidine alkaloids by thin layer chromatography
Authors: Molyneux Russell J. , James Lynn F. , Panter Kip E. , Ralphs Michael H.
Published: March 2007

A spray reagent which is sensitive and specific for polyhydroxyindolizidine glycosidase inhibitors such as swainsonine and castanospermine has been developed for their visualization on thin layer chromatographic plates. The method involves treatment of the plates with a sequential system consisting of 10% acetic anhydride in benzene, followed by Ehrlich's reagent. This technique has been used to follow the isolation and purification of minor alkaloidal constituents from Astragalus lentiginosus and Castanospermum australe. The occurrence of swainsonine and its N‐oxide in a number of Astragalus and Oxytropis species has been investigated. Species previously incriminated as locoweeds on the basis of field observations were all shown to contain the alkaloid and it was also found to occur in additional species. The highest levels of swainsonine were found in the seeds and pods, with lesser amounts in the leaves and stems, and none detectable in the roots.
Strategy for the isolation and identification of coumarins with calcium antagonistic properties from the roots of Angelica archangelica
Authors: Härmälä P. , Vuorela H. , Hiltunen R. , Nyiredy Sz. , Sticher O. , Törnquist K. , Kaltia S.
Published: March 2007

Fifteen coumarins, 2′‐angeloyl‐3′‐isovaleryl vaginate (4), archangelicin (3), oxypeucedanin hydrate (8), bergapten (5), byakangelicin angelate (15), imperatorin (11), isoimperatorin (6), isopimpinellin (13), 8‐[2‐(3‐methylbutroxy)‐3‐hydroxy‐3‐methylbutoxy]psoralen (12), osthol (1), ostruthol (9), oxypeucedanin (7), phellopterin (14), psoralen (2) and xanthotoxin (10), have been isolated from a chloroform extract of the roots of Angelica archangelica L. subsp. archangelica (Apiaceae). 2, 4, 12, and 15 are reported for the first time from A. archangelica L. The isolation was carried out using medium pressure liquid chromatography (MPLC) using the normal phase mode and then subsequently using a combination of the reversed and normal phase techniques. The eluents were optimized by thin layer chromatography and high performance liquid chromatography preassays according to the “PRISMA” system, and then transferred without modification of the solvent selectivity to preparative MPLC separations. The structures of the compounds were elucidated by a combination of spectroscopic methods. The isolation was carried out from a chloroform extract which in earlier tests had exhibited calcium blocking activity on the uptake of 45Ca2+ in clonal rat pituitary GH4C1 cells. The calcium antagonistic activity of the isolated compounds was then tested using the same method as for the extracts. All the coumarins tested exhibited calcium antagonistic activity. Archangelicin showed activity significantly higher than that of verapamil in this test system.
The quantitative analysis of seed proteins from peas using high performance liquid chromatography
Authors: Chambers Stephen J. , Bacon James R. , Lambert Nigel
Published: March 2007

Hydroxyapatite chromatography is frequently employed in the purification of pea seed proteins. By scaling down the procedure and interfacing it to a high performance liquid chromatographic (HPLC) system a method has been developed for the quantitative analysis of seed proteins not only from pea but potentially many other seeds. Under appropriate conditions three peaks were eluted from the column after first washing with a saline buffer. The peaks were shown by SDS‐polyacryamide gel electrophoresis to correspond to albumin, legumin and vicilin respectively. The technique provides results of a high degree of accuracy. Protein compositions were determined for six commercial pea varieties, with each analysis taking one hour and requiring less than one milligram of protein extract. Multiple loadings of the same sample indicated a very high level of reproducibility. The HPLC method revealed significantly higher levels of albumin compared with published values, and demonstrated the unreliability of fractionating globulins and albumins on the basis of solubility. The merits of this technique relative to alternative methods are discussed.
A kinetic method for assay of plant peroxidase and catalase activities by chemiluminescence
Authors: Frébort Ivo , Haviger Antonín , Jílek Milan
Published: March 2007

A chemiluminescent method for the simultaneous assay of peroxidase and catalase activities and chemical traps and quenchers of free radicals in natural samples, based on the additions of peroxidase standards, is presented. The method was standardized with horseradish peroxidase and beef liver catalase. The theoretical basis, mathematical treatment and computer processing of the method are described. The technique was used to analyse 25 samples of various common fruits and vegetables. The levels of peroxidase activity thus determined were compared with those obtained using the guaiacol method and were found to be in good agreement. The relationship between the shape of the chemiluminescent curves and the proportions of peroxidase and catalase activities and traps and quenchers are discussed.
Separation and identification of flavone, flavonol, isoflavone and flavanone aglycones by capillary column gas chromatography
Authors: Koupai‐Abyazani Mohammed R. , Creaser Colin S. , Stephenson G. Richard
Published: March 2007

A rapid and sensitive capillary column gas chromatographic method for the separation and identification of trimethylsilyl derivatives of flavonoid aglycones is reported. Well‐resolved, sharp and symmetrical peaks were obtained for a wide range of flavone, flavonol, isoflavone and flavanone aglycones with a variety of substitution patterns. Chromatographic behaviour and the effects of the number, position and type of the substituents on the retention times of these compounds have been defined.
Mass spectrometry of underivatized naturally occurring glycosides
Authors: Wolfender Jean‐Luc , Maillard Marc , Marston Andrew , Hostettmann Kurt
Published: March 2007

Mass spectrometry is essential for the structure determination of naturally occurring glycosides. Molecular weight and sugar sequence information can be obtained. Development of “soft” ionization techniques has allowed a direct mass spectrometric investigation of underivatized glycosides. Numerous different and complementary methods of ionization have been used for their study. For a given compound, the choice of a particular technique is crucial in order to obtain the structural information needed. A brief survey of these ionization techniques is given, together with examples of their use in major classes of plant glycosides.
Reversed phase thin layer chromatographic methods for separation of cytokinins
Authors: Letham D. S. , Singh S. , Willcocks D. A.
Published: March 2007

Silica gel layers were impregnated with a range of hydrophobic products. Only two such materials, liquid paraffin and the silicone fluid dimethylpolysiloxane, yielded thin layers which separated cytokinins effectively by reversed phase chromatography. The chromatographic behaviour of numerous cytokinins on these layers using a number of solvents is reported. The use of the layers and of integrated normal phase‐reversed phase thin layer chromatographic systems to separate cytokinins in crude extracts is discussed.
Macrocyclic trichothecenes from brazilian Baccharis species: From microanalysis to large‐scale isolation
Authors: Jarvis Bruce B.
Published: March 2007

Two Brazilian species of Baccharis, B. megapotamica and B. coridifolia, have been shown to contain a number of macrocyclic trichothecene antibiotics, some of which are identical to those produced by the common soil fungi Myrothecium. A number of different materials and methods have been used in a large‐scale (1800 kg) isolation procedure and in the chemical analysis of plant material, inter alia ferric gel precipitation, fractionation using polyethyleneimine impregnated silica gel and countercurrent chromatography.
The determination of the petroselinic acid content of coriander (Coriandrum sativum) oil by capillary gas chromatography
Authors: Griffiths D. Wynne , Robertson Graeme W. , Millam Stephen , Holmes Amanda C.
Published: March 2007

A rapid capillary gas chromatographic method has been developed for screening coriander fruits for petroselinic acid content. The method also permits determination of the concentrations of the other major long‐chain fatty acids present in coriander oil and allows an estimate of the total oil content of the sample to be determined. The method is applicable at the single fruit level and the results of analysing the constituent husk and embryo fractions have shown significant differences between their fatty acid compositions.
Enantiodifferentiation of isomeric vitispiranes
Authors: Herion P. , Full G. , Winterhalter P. , Schreier P. , Bicchi C.
Published: March 2007

Two optically enriched theaspirone isomers, i.e. (2S,5S)‐( − )‐theaspirone 2b and (2S,5R)‐( + )‐theaspirone 2c (ee‐values: 86% and 88% respectively), were obtained from quince juice by solvent extraction, flash chromatography and subsequent preparative high performance liquid chromatography (HPLC). Their absolute stereochemistry was assigned by circular dichroism spectroscopy. LiAlH4 reduction of 2b and 2c yielded 8‐hydroxytheaspirane isomers 3b and 3c which were subjected to thermal treatment at pH 3 leading to vitispirane isomers 1b and 1c. In the same manner, vitispirane racemates 1a/1b and 1c/1d were obtained from the synthetic theaspirones 2a/2b and 2c/2d which had been separated by multi‐layer coil countercurrent chromatography/HPLC. The optically enriched reference compounds were used to determine the order of elution in the course of enantio‐separation of 1a‐1d which was achieved by multidimensional gas chromatography (MDGC) using DB‐Wax and 2,6‐dimethyl‐3‐pentyl‐β‐cyclodextrin capillary columns. Using on‐line coupled MDGC‐mass spectrometry in the single ion monitoring mode, enantiodifferentiation of 1a‐1d as well as 2a‐2d from a number of natural sources was performed.
Screening of seed lipids for γ‐linolenic acid: Capillary gas‐liquid chromatographic separation of 18:3 fatty acids with Δ5 and Δ6 double bonds
Authors: Aitzetmüller K. , Werner Gisela , Tsevegsüren Nansadyn
Published: March 2007

γ‐Linolenic acid (6c,9c,12c‐18:3) has recently become important for dietary and pharmaceutical applications. The reported occurrence of γ‐linolenic acid in seed oils from plant families known to produce fatty acids, including 18:3 acids, with Δ5‐cis and Δ5‐trans double bonds makes it necessary to distinguish between 5c,9c,12c‐, 5t,9c,12c‐ and 6c,9c,12c‐octadecatrienoic acids by gas chromatography (GC) alone in routine screening operations. The separation of these acids using two different capillary GC systems has been investigated. The successful separation of octadecatrienoic acids with 5c, 5t and 6c double bonds is shown by way of gas chromatograms of the fatty acid methyl esters obtained from the seed oils of four different species of the family Ranunculaceae and of Xeranthemum and Pinus.
Analysis of secondary metabolites from Lichen by high performance liquid chromatography with a photodiode array detector
Authors: Yoshimura Isao , Kinoshita Yasuhiro , Yamamoto Yoshikazu , Huneck Siegfried , Yamada Yasuyuki
Published: March 2007

Secondary metabolites from Lichen, mainly phenolic compounds, have been analysed and identified using high performance liquid chromatography with a photodiode array detector. Components of lichen thalli were detected by characteristic ultraviolet spectra and relative retention times. Some new minor components have been found in several lichens.
A simple spectrophotometric assay for plant 5′‐deoxy‐5′‐methylthioadenosine nucleosidase using xanthine oxidase as a coupling enzyme
Authors: Dunn Steven M. , Bryant John A. , Kerr Michael W.
Published: March 2007

The first step in the metabolic salvage of methionine from 5′‐deoxy‐5′‐methylthioadenosine, generated as a by‐product of polyamine and ethylene biosynthesis, is the hydrolytic cleavage of the adenine base from the pentose sugar by a specific nucleosidase. A continuous coupled assay procedure for this enzyme has been developed which exploits the ability of xanthine oxidase to utilise free adenine as a substrate and represents a convenient alternative to pre‐existing radioisotopic methods. Two variations of the basic technique are described and their suitability both for routine chromatographic monitoring and for more stringent kinetic analyses is discussed. Kinetic data obtained via this procedure for the methylthioadenosine nucleosidase enzyme from Pisum sativum was shown to be consistent with previously published data.
Factors involved in the high pressure liquid chromatographic separation of alkenes by means of argentation chromatography on ion exchangers: Overview of theory and new practical developments
Authors: van Beek Teris A. , Subrtova Dana
Published: March 2007

The literature on the use and theory of silver(I) complexation (argentation) chromatography is reviewed. Apolar isomeric alkenes, for example numerous terpenes and fatty acids, can be well resolved by means of high pressure liquid chromatography on cation exchange materials coated with silver(I) ions, but unfortunately the mechanism on which these separations are based is not fully understood. As part of an attempt to provide a predictive model for the separation of volatile alkenes, the retention of more than 40 C2‐C10 olefins besides a number of C14‐pheromones and volatile terpenes is given and the results discussed. The separation is mainly governed by the type and number of double bonds (isolated, conjugated or aromatic), their steric accessibility (number and size of substituents) for complexation with silver(I) ions, the relief of inherent strain upon complexation and electron donating or withdrawing groups, or polar groups close to the double bond. Polar groups such as hydroxyls also complex weakly with silver. Other functional groups, including carbonyls, and the overall polarity of the solute play only a minor role. Similarly most solvents have only a limited influence on the selectivity and speed of separation, and function more as a transportation medium as in gas chromatography. A comparative model which gives semi‐quantitative estimations of the retention time of most volatile olefins in methanol is presented. Substituent parameters (Ags) which quantitatively forecast the influence of different alkyl side chains are part of this model.
Prenatal diagnosis of thalassemia major by fetal blood analysis: Experience with 1000 cases
Authors: Cao Antonio , Falchi Angela M. , Tuveri Teresa , Scalas Maria T. , Monni Giovanni , Rosatelli Cristina
Published: March 2007

In this report we have summarized our experience with the prenatal diagnosis of β‐thalassemia in 1000 pregnancies followed at least until 12 months after birth. In the majority of these cases, the thalassemia lesion was the nonsense mutation at the codon corresponding to amino acid 39, which produces the hematological phenotype of β‐thalassemia. Fetal blood sampling was carried out by placental aspiration, by which a sufficient amount of fetal blood for analysis was obtained in the majority of cases (99 per cent). The fetal mortality associated with fetal blood sampling was 6·3 per cent. Those placental samples contaminated by maternal cells were successfully purified by Ørskov lysis. Fetal blood was analysed by globin chain synthesis on CM–52 columns, which gave reliable results. Two misdiagnoses (0·2 per cent) have been made of which one was due to a non‐globin protein co‐migrating with the β‐chains while the other resulted from a misclassification of the type of thalassemia segregating in the family.
Adult‐onset GM2 gangliosidosis diagnosed in a fetus
Authors: Navon R. , Sandbank U. , Frisch A. , Baram D. , Adam A.
Published: March 2007

Amniocentesis and subsequent tests are reported on a fetus conceived of a rare mating type: its mother has an intermediate level of β hexosaminidase A (HEX A), characteristic of carriers of Tay‐Sachs disease (TSD), while the father suffers from an adult‐onset GM2 ganglio‐sidosis (AOG) with severe HEX A deficiency. Activity of HEX A in the cultured fetal cells was very low when measured by the heat‐inactivation method, thus showing the typical biochemical phenotype of TSD fetuses. However, upon separation of HEX isozymes by ion exchange chromatography, residual HEX A (17 per cent of total HEX) was demonstrated. Also in contrast to TSD fetuses, this fetus' fibroblasts were able to synthesize the precursor of a chains of HEX, and ultrastructural examination of its brain revealed few atypical lamellar bodies, unlike those found in TSD fetuses of the same gestational age. It is therefore concluded that the fetus was not affected with TSD, but rather with AOG.
Activity of biotin‐dependent and gaba metabolizing enzymes in chorionic villus samples: Potential for 1st trimester prenatal diagnosis
Authors: Sweetman Frances R. , Gibson Kenneth M. , Sweetman Lawrence , Nyhan William L. , Chin Homer , Swartz William , Jones Oliver W.
Published: March 2007

We have documented the presence of five mitochondrial enzymes in samples of chorionic villus tissue and measured the levels of activity. Three of the enzymes catalyse biotindependent reactions. These are propionyl‐CoA carboxylase, 3‐methylcrotonyl‐CoA carboxylase and pyruvate carboxylase. the other enzymes. 4‐aminobutyric acid aminotransferase and succinic semialdehyde dehydrogenase, are involved inthe degradation of the central inhibitory neurotransmitter GABA. Distinct diseases in whichthere is deficiency of each of these enzymes have been documented in man. Significant levels of activity were observed for all five enzymes in chorionic villus tissue. This methodology should permit early prenatal diagnosis of deficiencies of these enzymes by chorionic villus biopsy in the first trimester.
Amniotic fluid macrophages from normal and malformed fetuses
Authors: Medina‐Gomez P. , McBride W. H.
Published: March 2007

Amniotic fluid cells from normal and abnormal fetuses (neural tube defects and abdominal wall lesions) were examined uncultured and after short‐term culture for macrophages. Morphology, adherence, phagocytosis, presence of Fc receptors and non‐specific esterase were studied. The existence of macrophages in normal and abnormal fluids was confirmed, although the percentage and the absolute numbers varied greatly from specimen to specimen. The most marked increases in total macrophages were in cases of anencephaly. The significance of these macrophages and their value in prenatal diagnosis are discussed.
Possibility of prenatal diagnosis of hereditary triose phosphate isomerase deficiency
Authors: Rosa R. , Prehu M. O. , Calvin M. C. , Daffos F. , Forestier F.
Published: March 2007

Prenatal diagnosis has been performed on umbilical cord blood of an 18 weeks fetus of heterozygous triosephosphate isomerase (TPI) deficient parents. After excluding maternal blood contamination, TPI activity was measured and found to be 60 per cent of the normal mean whereas the value of glucose‐6‐phosphate dehydrogenase activity was in the normal range of fetal blood. In addition, the analysis of the characteristics of fetal TPI, i.e. Km measurements for glyceraldehyde‐3‐phosphate, heat stability tests and electrophoretic studies, did not show any evidence of a special form of TPI in fetal blood. These results were consistent with the heterozygous state and were confirmed at birth.
Implications of 'low maternal serum alpha‐fetoprotein levels: Are maternal age risk criteria obsolete?
Authors: Martin Alice O. , Llu Kiang
Published: March 2007

An association has been reported between “low” maternal serum alpha‐fetoprotein (MSAFP) and fetal chromosome abnormalities, notably Down syndrome. We suggest the predictive value be used for genetic counselling when a “low” MSAFP is found, and present an illustrative risk table. It can also be seen that normal MSAFP in a woman may lower her age‐related risks below that previously defined as “high risk”. However, until good estimates of sensitivity and specificity are available from prospective, population based studies, patients should be told that any risk estimates are rough approximations. When good estimates are available, use of age risks alone may become obsolete.
Prenatal ultrasonic diagnosis of familial asymmetric septal hypertrophy
Authors: Stewart Patricia A. , Buis‐Liem Tjik , Verwey Robert A. , Wladimiroff Juriy W.
Published: March 2007

Hypertrophic cardiomyopathy usually manifests clinically in the second or third decade of life. Two dimensional echocardiography is a reliable indicator of the presence of the disease. This technique is of use in the screening of fetuses at risk for familial cardiomyopathy. This report describes the prenatal echocardiographic detection of hypertrophic cardiomyopathy in the fetus of a mother with hypertrophic cardiomyopathy localized to the apical region of the left ventricle.
Prenatal diagnosis of non‐ketotic hyperglycinemia
Authors: Applegarth D. A. , Levy H. L. , Shih V. E. , McGillivray B. , Wong J. T. , Toone J. R. , Kirby L. T.
Published: March 2007

We describe successful prenatal diagnosis in four pregnancies at risk for non‐ketotic hyperglycinemia, two affected and two unaffected, using the glycine level and the glycine/ serine ratio in amniotic fluid obtained at 16 weeks gestational age. Although this method of prenatal diagnosis for non‐ketotic hyperglycinemia has been effective in our hands the narrow differences between affected and unaffected pregnancies indicate the need for caution concerning its reliability.
Estimation of the weight of chorionic villus samples obtained from first trimester pregnancies by transcervical aspiration
Authors: Newport Melanie , Coleman Dulcie V. , McPherson Klim
Published: March 2007

Eight obstetricians experienced in chorionic villus sampling were asked to estimate the weight of samples of villi with and without a reference photograph. Referral to the photograph significantly improved the accuracy of their estimations.
Prenatal diagnosis of familial tuberous sclerosis following detection of cardiac rhabdomyoma by ultrasound
Authors: Journel H. , Roussey M. , Plais M. H. , Milon J. , Almange C. , Le Marec B.
Published: March 2007

The authors report a case of tuberous sclerosis (TS), diagnosed by prenatal ultrasound, which was suspected by the detection of intracardiac tumours and confirmed by the family investigation. Cardiac rhabdomyomata can be visualized early on echography and must suggest this diagnosis. The place of genetic counselling and prenatal diagnosis in TS is examined.
Biochemical analysis of meconium in fetuses presumed to have cystic fibrosis
Authors: Brock David J. H. , Barron Lilias
Published: March 2007

A series of proteins (albumin, transferrin, a1‐ antitrypsin, alpha‐fetoprotein and pancreatic oncofetal antigen) and enzymes (γ‐glutamyltranspeptidase, aminopeptidase M, alkaline phosphatase, a‐glucosidase and protease) was measured in fetal meconium extracts. There were 19 fetuses thought to have cystic fibrosis (CF), 13 with neural tube defects, three with chromosome abnormalities and 19 normal controls, all with gestational ages between 18 and 21 weeks.

With the exception of alpha‐fetoprotein, all the proteins and enzymes were significantly elevated in the CF meconium extracts. The most definitive indicator of a CF fetus was the albumin concentration, where the mean level was five times that found in the control groups. However, five of 19 fetuses assumed to have CF had albumin in the normal range. In these cases the meconium protease levels were grossly elevated. Furthermore, in the same five fetuses meconium concentration of pancreatic oncofetal antigen, a protein synthesized in the fetal pancreas, was also greatly raised.

We suggest that post‐mortem examination of a fetus thought to have CF should include measurement of meconium albumin, protease and pancreatic oncofetal antigen.
Prenatal identification of a Y‐chromosome deletion by Y‐specific single copy DNA probes
Authors: Gilgenkrantz S. , Droulle P. , Seboun E. , Casanova M. , Schweitzer M. , Goosens M. , Fellous M.
Published: March 2007

A sex chromosome deletion was identified in the course of prenatal diagnosis for maternal age. Ultrasound pictures revealed male fetal sex and a comparison with the father's Y chromosome suggested that the altered chromosome might be a de novo deletion of the Y chromosome. DNA hybridization with five human Y‐specific probes shows that, among the Y‐specific sequences recognized by the probes, only two of them are absent. The normal infant, at birth, was mosaic 46, XYq‐ /46,XY.
Prenatal diagnosis of cystinosis utilizing chorionic villus sampling
Authors: Smith M. L. , Pellett O. L. , Cass M. M. J. , Kennaway N. G. , Buist N. R. M. , Buckmaster J. , Golbus M. , Spear G. S. , Schneider J. A.
Published: March 2007

The prenatal diagnosis of cystinosis is currently based on the increased amount of free‐cystine present in amniotic fluid cells. Amniocyte cultures must be grown for at least 2 weeks to obtain sufficient cells for such measurements. Thus, the diagnosis cannot be made until close to 20 weeks gestational age by this method. We report a case in which chorionic villi were used for direct cystine measurement resulting in the in utero diagnosis of cystinosis at 9 weeks gestational age. The diagnosis was confirmed by the study of cultured chorionic villus cells, and of the 10‐week abortus.
Expression of transcobalamin II by amniocytes
Authors: Rosenblatt David S. , Hosack Angela , Matiaszuk Nora
Published: March 2007

Children with a genetic absence of transcobalarnin 2 (TC2) are clinically asymptomatic at birth but develop severe megaloblastic anemia early in life. We have examined the incorporation of [57Co]‐CN‐B12 in the absence of any exogenous source of TC2 in control amniotic fluid derived cells and cultured diploid fibroblasts, and in fibroblasts from a patient with TC2 deficiency. Both control fibroblasts and arnniocytes incorporated labelled B12, into TC2‐B12, and the proportion of labelled TC2‐B12 could be increased by growing cells in the presence of chloroquine which prevents intralysosomal hydrolysis of the TC2‐B12 complex. In contrast, fibroblasts from the patient with TC2 deficiency incorporated almost no label as TC2‐B12. These studies suggest that TC2 deficiency either due to aberrant production of TC2 or because of the production of an abnormal TC2 which does not bind B12 can be diagnosed before birth.
Continuous subcutaneous insulin infusion (CSII) in pregnant diabetic patients
Authors: Caruso A. , Lanzone A. , Bianchi V. , Massidda M. , Castelli M. P. , Fulghesu A. M. , Mancuso S.
Published: March 2007

The efficacy of the insulin infusion pump (CSII) in pregnancy was examined in 12 diabetic patients and compared with intermittent insulin therapy (IIT). In patients poorly controlled on IIT constant and rapid equilibrium was achieved with CSII (mean of glucose levels: CSII versus IIT=84 versus 137 mg/dl; S.D. = 36 versus 63 mg/dl; mean amplitude of glycemic excursion (MAGE)=65 versus 112 mg/dl. In patients well controlled on IIT, CSII led to a reduction in the variation of glucose excursions (S.D.= 29 versus 36 mg/dl; MAGE=48 versus 76 mg/dl). CSII generally produced a reduction of 20–37 per cent of daily insulin dose (in three cases there was an increase of dose with the achievement of glycemic control). Furthermore in CSII treated‐patients amniotic glucose, insulin and C‐peptide concentrations werefound tobeinthenormalrange(22.1±10.1 mg/dl; 5.2±2.7μ/ml; 1.25±0.71 ng/ml, respectively). All infants were horn at or near‐term, had no macrosomia or neonatal problems. It is concluded that CSII is a highly efficient way to achieve normal glucose levels in pregnancy, not only in type I, hut also in type II or gestational diabetes.
First trimester diagnosis of cystinosis using intact chorionic villi
Authors: Patrick A. D. , Young E. P. , Mossman J. , Warren R. , Kearney L. , Rodeck C. H.
Published: March 2007

Cystinosis was diagnosed in the first trimester of pregnancy by studies of uptake and retention of [35S]‐cystine by intact biopsy samples of chorionic villi. The diagnosis was confirmed by similar studies on cell cultures of villi and fetal skin fibroblasts.