Multi-element speciation of metalloproteins in fish tissue using size-exclusion chromatography coupled "on-line" with ICP-isotope dilution-time-of-flight-mass spectrometry.

An on-line isotope dilution (ID) method in combination with the coupling of size-exclusion high-performance liquid chromatography (SE-HPLC) to an axial inductively coupled plasma time-of-flight mass spectrometer (ICP-TOFMS) was applied to the quantitative speciation of Cu, Zn and Cd in carp and eel cytosols. Quantitative information on the distribution of essential and toxic metals between the different molecular weight fractions in kidney cytosols of control and Cd exposed carp was obtained with species-unspecific spiking by post-column addition of the enriched isotopes 65Cu, 67Zn and 106Cd. The isotope ratios 63Cu/65Cu, 64Zn/67Zn and 114Cd/106Cd, were monitored by ICP-TOFMS in transient signal mode.

Do thickening properties of locust bean gum affect the amount of calcium, iron and zinc available for absorption from infant formula? In vitro studies.

Locust bean gum acts as a milk thickener in infant formula because of its high apparent viscosity. The effects of such thickening agents on metabolic and physiologic responses during infancy have not been clarified sufficiently. Due to the increased volume of the digest and the bulking and trapping effects, digestion and absorption of nutrients may be influenced in presence of locust bean gum.

Progressive external ophthalmoplegia characterized by multiple deletions of mitochondrial DNA: unraveling the pathogenesis of human mitochondrial DNA instability and the initiation of a genetic classification.

Over the last decade, many sporadic and familial cases have been reported with multiple deletions of mitochondrial DNA (mtDNA) in postmitotic tissues. Most patients suffer from progressive external ophthalmoplegia (PEO) and may have a nuclear gene defect that predisposes to the accumulation of mtDNA deletions. Recently, positional cloning has led to the discovery of mutations in four such nuclear genes.

Nitric oxide donor molsidomine favors features of atherosclerotic plaque stability during cholesterol lowering in rabbits.

Rupture-prone atherosclerotic plaques are characterized by a thin fibrous cap containing numerous macrophage-derived foam cells and few smooth muscle cells (SMC). Decreasing the ratio between macrophages and SMC might favor plaque stabilization. Macrophages expressing inducible nitric oxide (NO) synthase become hypersensitive to killing by exogenous NO donors.

Variation of heavy metals within and among feathers of birds of prey: effects of molt and external contamination.

In this study we examined the effect of external contamination on the heavy metal (Ag, Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) concentration in feathers. We compared the heavy metal content among the 10 primary wing feathers of sparrowhawks (Accipiter nisus), little owls (Athene nocta) and barn owls (Tyto alba) and the variation within the outermost tail feather of sparrowhawks and tawny owls (Strix aluco). The concentration of Hg was significantly higher in feathers molted first, suggesting that levels in feathers reflect levels in the blood during formation.

De novo SCN1A mutations are a major cause of severe myoclonic epilepsy of infancy.

Severe myoclonic epilepsy of infancy (SMEI or Dravet syndrome) is a rare disorder occurring in young children often without a family history of a similar disorder. The earliest disease manifestations are usually fever-associated seizures. Later in life, patients display different types of afebrile seizures including myoclonic seizures.

Alteration of the purinergic modulation of enteric neurotransmission in the mouse ileum during chronic intestinal inflammation.

1. The effect of chronic intestinal inflammation on the purinergic modulation of cholinergic neurotransmission was studied in the mouse ileum. Chronic intestinal inflammation was induced by infection of mice with the parasite Schistosoma mansoni during 16 weeks.

Extraction and quantitative analysis of 1-aminocyclopropane-1-carboxylic acid in plant tissue by gas chromatography coupled to mass spectrometry.

We developed a new method for the determination of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) using quantitative GC-negative chemical ionisation MS as a detection and quantification system, in combination with isotope dilution using [2H4]ACC and an off-line solid-phase extraction. By derivatisation with pentafluorobenzyl bromide, ACC could easily be detected with m/z 280 being the most abundant ion. Determination of this component resulted in a detection limit of 10 fmol and a linear fit in the 100 fmol-100 pmol range.

Improved detection of rhinoviruses by nucleic acid sequence-based amplification after nucleotide sequence determination of the 5' noncoding regions of additional rhinovirus strains.

The isothermal nucleic acid sequence-based amplification (NASBA) system was applied for the detection of rhinoviruses using primers targeted at the 5' noncoding region (5' NCR) of the viral genome. The nucleotide sequence of the 5' NCRs of 34 rhinovirus isolates was determined to map the most conserved regions and design more appropriate primers and probes. The assay amplified RNA extracted from 30 rhinovirus reference strains and 88 rhinovirus isolates, it did not amplify RNA from 49 enterovirus isolates and other respiratory viruses.

Age-related hearing impairment (ARHI): environmental risk factors and genetic prospects.

This paper reviews what is known about the environmental risk factors and medical conditions that contribute to age-related hearing impairment (ARHI), and evaluates which analyses could be performed to identify genetic factors that are involved. Although hearing acuity declines with aging in everybody, the variation in hearing thresholds is large. Part of this variation can be explained by medical conditions, and by a different exposure to environmental factors.

Comparison of the sulforhodamine B assay and the clonogenic assay for in vitro chemoradiation studies.

Purpose: Since there is a growing interest in preclinical research on interactions between radiation and cytotoxic agents, this study focused on the development of an alternative to the very laborious clonogenic assay (CA).

Methods: The colorimetric sulforhodamine B (SRB) assay was compared to the clonogenic assay for radiosensitivity testing in two lung cancer cell lines (A549, H292), one colon cancer cell line (HT-29) and one breast cancer cell line (MCF-7). In addition, the combination of the radiosensitizing agent gemcitabine and radiation was investigated with both assays.

The radiosensitising effect of gemcitabine and the influence of the rescue agent amifostine in vitro.

In this study, the radiosensitising effect of different concentrations of gemcitabine and the combination of gemcitabine/radiotherapy with the rescue agent amifostine was investigated in different human tumour cell lines. The cells were treated with gemcitabine (0-8 nM) for 24 h prior to radiation (0-8 Gy). Amifostine (ami) and alkaline phosphatase (AP) were added 30 min before radiation.

A novel CpG-associated brain-expressed candidate gene for chromosome 18q-linked bipolar disorder.

We previously identified 18q21-q22 as a candidate region for bipolar (BP) disorder and constructed a yeast artificial chromosome (YAC) contig map. Here we identified three potential CpG islands using CCG/CGG YAC fragmentation. Analysis of available genomic sequences using bioinformatic tools identified an exon of 3639 bp downstream of a CpG island of 1.

Cytokinin affinity purification and identification of a tobacco BY-2 adenosine kinase.

Adenosine kinase is one of the enzymes potentially responsible for the formation of cytokinin nucleotides in plants. Using a zeatin affinity column a 40 kDa protein was isolated from tobacco Bright Yellow 2 (TBY-2) and identified by mass spectrometry as adenosine kinase. The ligand interaction reported here can be disrupted by several other adenine- but not guanine-based purine derivatives.

Xyloglucan endotransglucosylase action is high in the root elongation zone and in the trichoblasts of all vascular plants from Selaginella to Zea mays.

The endotransglucosylase action of the enzyme xyloglucan endotransglucosylase/hydrolase (XTH) was localized in the roots of diverse vascular plants: club-mosses (lycopodiophytes), ferns, gymnosperms, monocots, and dicots. High action was always found in the epidermis cell wall of the elongation zone and in trichoblasts in the differentiation zone. Clearly XTH and its action in root development evolved before the evolutionary divergence of ferns and seed plants and also of the lycopodiophytes and euphyllophytes.

Direct stereochemical assignment of hexose and pentose residues in flavonoid O-glycosides by fast atom bombardment and electrospray ionization mass spectrometry.

Mass spectrometric methods have been developed which allow the direct stereochemical assignment of terminal monosaccharide residues in flavonoid O-glycosides without the need for chemical hydrolysis. Standards containing a glucose, galactose, mannose, xylose, arabinose or apiose residue were examined because these monosaccharides are by far the most commonly encountered in flavonoid glycosides. Following acetylation, the major peracetylated sugar related fragments, generated by fast atom bombardment (FAB) or electrospray ionization (ESI), were selected for collisional activation employing a broad range of collision energies.

Development of a gas chromatographic/ion trap mass spectrometric method for the determination of levoglucosan and saccharidic compounds in atmospheric aerosols. Application to urban aerosols.

We developed and validated a gas chromatographic/ion trap mass spectrometric method for the determination of levoglucosan and the related monosaccharide anhydrides, mannosan, galactosan and 1,6-anhydro-beta-D-glucofuranose in urban atmospheric aerosols collected on quartz fiber filters. The method is based on extraction with dichloromethane-methanol (80 : 20, v/v), trimethylsilylation, multiple reaction monitoring in the tandem mass spectrometric mode using the ion at m/z 217, and the use of an internal standard calibration procedure with the structurally related compound methyl beta-L-arabinopyranoside. In addition, the method allows the quantification of other saccharidic compounds, arabitol, mannitol, glucose, fructose, inositol and sucrose, which were found to be important in summer aerosols.

Optimization of a liquid chromatography method based on simultaneous electrospray ionization mass spectrometric and ultraviolet photodiode array detection for analysis of flavonoid glycosides.

Different reversed-phase liquid chromatography (LC) columns of conventional dimensions were coupled to an ultraviolet photodiode array detector (UV-DAD) and a magnetic sector-type spectrometer, equipped with an electrospray ionization (ESI) source, by a laboratory-made flow splitter. A mixture of three flavonoid-O-glycosides was employed to examine the effects of the solvent composition, the flow rate, the stationary phase, the pH and the organic acid added, on the chromatographic separation, the UV-DAD detection, the ESI process and the entire LC system with ESI-MS and UV-DAD detection. In the positive ion mode, methanol containing 1% acetic acid was by far the most sensitive in ESI-MS analysis, whereas an acetonitrile/water mobile phase containing 0.

Tau negative frontal lobe dementia at 17q21: significant finemapping of the candidate region to a 4.8 cM interval.

We report the results of a genome-wide search in a four-generation pedigree with autosomal dominant early-onset dementia (mean onset age: 64.9 years, range 53-79 years). In this family we previously excluded the known Alzheimer's disease genes based on linkage analysis and mutation screening of the amyloid precursor protein gene (exons 16 and 17) and the presenilin 1 and 2 genes.

Cellulose orientation in the outer epidermal wall of angiosperm roots: implications for biosystematics.

The net orientation of cellulose fibrils in the outer epidermal wall of the root elongation zone of 57 angiosperm species belonging to 29 families was determined by means of Congo Red fluorescence and polarization confocal microscopy. The angiosperms can be divided in three groups. In all but four plant families, the net orientation of the cellulose fibrils is transverse to the root axis.

A novel homozygous missense mutation in the myotubularin-related protein 2 gene associated with recessive Charcot-Marie-Tooth disease with irregularly folded myelin sheaths.

Mutations in the myotubularin-related protein 2 gene on chromosome 11q22 are known to cause autosomal recessive Charcot-Marie-Tooth disease with irregularly folded myelin sheaths. We screened the coding region of the myotubularin-related protein 2 gene in a Turkish consanguineous Charcot-Marie-Tooth disease family compatible with linkage to chromosome 11q22. A homozygous cytosine to thymine missense mutation at nucleotide position 847, resulting in an amino acid substitution of arginine to tryptophan at codon 283, was detected in exon 9 of the MTMR2 gene.

A three-dimensional quantitative analysis of restenosis parameters after balloon angioplasty: comparison between semi-automatic computer-assisted planimetry and stereology.

Semi-automatic computer-assisted planimetry is often used for the quantification of restenosis parameters after balloon angioplasty although it is a time-consuming method. Moreover, slicing the artery to enable analysis of two-dimensional (2-D) images leads to a loss of information since the vessel structure is three-dimensional (3-D). Cavalieri's principle uses systematic random sampling allowing 3-D quantification.

Development of potent and selective dipeptidyl peptidase II inhibitors.

Structure-activity investigations of product-like dipeptide analogues lacking the C-terminal carbonyl function resulted in potent and selective dipeptidyl peptidase II (DPP II) inhibitors. Dab-Pip has an IC(50)=0.13 microM for DPP II and a 7600-fold selectivity with respect to DPP IV.

Genetic diversity and condition factor: a significant relationship in Flemish but not in German populations of the European bullhead (Cottus gobio L.).

Although evidence of associations between genetic diversity and fitness in wild species has been published, the lack of a comprehensive review across species and the existence of contradictory results have led to scepticism remaining about its existence and importance in natural populations. In this study, the relationship between genetic diversity at six microsatellite loci and condition factor (a fitness related trait) was investigated at the population level in both Flemish and German populations of the European bullhead (Cottus gobio). A significant positive correlation was observed between genetic variability and the condition factor in Flemish but not in German bullhead populations.

Glutathione-like tripeptides as inhibitors of glutathionylspermidine synthetase. Part 2: substitution of the glycine part.

Glutathionylspermidine synthetase (GspS) is an essential enzyme in the biosynthesis of trypanothione and is an attractive target for the design of selective anti-parasitic drugs. We synthesised a series of analogues of glutathione (L-gamma-Glu-L-Leu-X) where the glycine moiety has been substituted for other amino acids. These peptides were evaluated as substrates and inhibitors of GspS.