Clinical experience with non-invasive prenatal screening for single-gene disorders

OBJECTIVE

To assess the performance of a non-invasive prenatal screening test (NIPT) for a panel of dominant single-gene disorders (SGD) with a combined population incidence of 1 in 600.

METHODS

Cell-free fetal DNA isolated from maternal plasma samples accessioned from 14 April 2017 to 27 November 2019 was analyzed by next-generation sequencing, targeting 30 genes, to look for pathogenic or likely pathogenic variants implicated in 25 dominant conditions. The conditions included Noonan spectrum disorders, skeletal disorders, craniosynostosis syndromes, Cornelia de Lange syndrome, Alagille syndrome, tuberous sclerosis, epileptic encephalopathy, SYNGAP1-related intellectual disability, CHARGE syndrome, Sotos syndrome and Rett syndrome. NIPT-SGD was made available as a clinical service to women with a singleton pregnancy at ≥ 9 weeks' gestation, with testing on maternal and paternal genomic DNA to assist in interpretation. A minimum of 4.5% fetal fraction was required for test interpretation. Variants identified in the mother were deemed inconclusive with respect to fetal carrier status. Confirmatory prenatal or postnatal diagnostic testing was recommended for all screen-positive patients and follow-up information was requested. The screen-positive rates with respect to the clinical indication for testing were evaluated.

RESULTS

A NIPT-SGD result was available for 2208 women, of which 125 (5.7%) were positive. Elevated test-positive rates were observed for referrals with a family history of a disorder on the panel (20/132 (15.2%)) or a primary indication of fetal long-bone abnormality (60/178 (33.7%)), fetal craniofacial abnormality (6/21 (28.6%)), fetal lymphatic abnormality (20/150 (13.3%)) or major fetal cardiac defect (4/31 (12.9%)). For paternal age ≥ 40 years as a sole risk factor, the test-positive rate was 2/912 (0.2%). Of the 125 positive cases, follow-up information was available for 67 (53.6%), with none classified as false-positive. No false-negative cases were identified.

CONCLUSIONS

NIPT can assist in the early detection of a set of SGD, particularly when either abnormal ultrasound findings or a family history is present. Additional clinical studies are needed to evaluate the optimal design of the gene panel, define target populations and assess patient acceptability. NIPT-SGD offers a safe and early prenatal screening option. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Impact of transesophageal electrophysiologic study to elucidate the mechanism of arrhythmia on children with supraventricular tachycardia and no preexcitation

An electrophysiologic study (EPS) of children and teenagers with paroxysmal supraventricular tachycardia (SVT) and normal electrocardiography (ECG) in sinus rhythm was evaluated. Generally, EPS is performed only before paroxysmal SVT ablation in these patients. In this study, 140 patients (mean age, 15 ± 3 years) with normal ECG in sinus rhythm were studied for SVT by a transesophageal route in baseline state and after isoproterenol. Idiopathic left or right ventricular tachycardia was diagnosed in four patients (3 %). Anterograde conduction over an atrioventricular (AV) left lateral (n = 10) or septal (n = 9) accessory pathway (AP) was noted in 19 patients (13.5 %) at atrial pacing. Orthodromic AV reentrant tachycardia (AVRT) was induced in these children. Five of the patients had a high rate conducted over AP (>240 bpm in baseline state or >290 bpm after isoproterenol). Two of the patients (a 10-year-old girl with well-tolerated SVT and a 17-year-old with syncope-related SVT) had the criteria for a malignant form with the induction of atrial fibrillation conducted over AP at a rate exceeding 290 bpm in baseline state. Of the 140 patients, 74 (53 %) had typical AV node reentrant tachycardia (AVNRT), nine had atypical AVNRT (6 %), 1 had atrial tachycardia (0.7 %), and 33 (23.5 %) had AVRT related to a concealed AP with only retrograde conduction. Electrophysiologic study is recommended for children with paroxysmal SVT and normal ECG in sinus rhythm. The data are helpful for guiding the treatment. Ventricular tachycardia or atrial tachycardia can be misdiagnosed. Masked preexcitation syndrome with anterograde conduction through AP was present in 13.5 % of the patients, and 1.4 % had a malignant preexcitation syndrome.

Photodissociation pathways and lifetimes of protonated peptides and their dimers

Photodissociation lifetimes and fragment channels of gas-phase, protonated YA(n) (n = 1,2) peptides and their dimers were measured with 266 nm photons. The protonated monomers were found to have a fast dissociation channel with an exponential lifetime of ~200 ns while the protonated dimers show an additional slow dissociation component with a lifetime of ~2 μs. Laser power dependence measurements enabled us to ascribe the fast channel in the monomer and the slow channel in the dimer to a one-photon process, whereas the fast dimer channel is from a two-photon process. The slow (1 photon) dissociation channel in the dimer was found to result in cleavage of the H-bonds after energy transfer through these H-bonds. In general, the dissociation of these protonated peptides is non-prompt and the decay time was found to increase with the size of the peptides. Quantum RRKM calculations of the microcanonical rate constants also confirmed a statistical nature of the photodissociation processes in the dipeptide monomers and dimers. The classical RRKM expression gives a rate constant as an analytical function of the number of active vibrational modes in the system, estimated separately on the basis of the equipartition theorem. It demonstrates encouraging results in predicting fragmentation lifetimes of protonated peptides. Finally, we present the first experimental evidence for a photo-induced conversion of tyrosine-containing peptides into monocyclic aromatic hydrocarbon along with a formamide molecule both found in space.

Sub-microsecond photodissociation pathways of gas phase adenosine 5'-monophosphate nucleotide ions

The sub-microsecond dissociation pathways for the protonated and deprotonated forms of adenosine 5'-monophosphate were probed in the gas phase using a linear time of flight spectrometer. The studies show two dissociation pathways for the AMP ions indicating dominant ergodic pathways in the photodissociation of these species. The photofragmentation was determined to be a single photon process for the AMP ions. Photodetachment of the AMP anion excited at 266 nm was not observed, leaving dissociation as the prominent pathway for relaxation of the excess energy in the biomolecule. The photofragments were analysed at the electrostatic ion storage ring (ELISA) and found to be similar to collision induced fragments in the case of anions but different in the case of cations.

Ion trajectory simulations in a high-pressure cylindrical ion trap

We present the simulation of a cylindrical ion trap (CIT) at high pressure (5-25 Torr range). SIMION 7.0 software was used for the simulations. The effect of pressure, RF frequency and trap dimensions has been investigated. The shape of stability diagrams at non-zero pressure is drastically different from the one observed in vacuum. Preliminary experimental results are shown, using a r = z = 3 mm-long CIT at 12 Torr for trapping peptide and protein ions.

Development of isohomoeoallelic lines within the wheat cv. Courtot for high molecular weight glutenin subunits: transfer of the Glu-D1 locus to chromosome 1A

Wheat quality depends on protein composition and grain protein content. High molecular weight glutenin subunits (HMW-GS) play an important role in determining the viscoelastic properties of gluten. In an attempt to improve the bread-making quality of hexaploid wheat by elaborating novel HMW-GS combinations, a fragment of wheat chromosome 1D containing the Glu-D1 locus encoding the Dx2+Dy12 subunits was translocated to the long arm of chromosome 1A using the ph1b mutation. The partially isohomoeoallelic line selected was characterized using cytogenetical and molecular approaches to assess the amount of chromatin introgressed in the translocated 1A chromosome. Triple-target genomic in situ hybridization indicated that the translocated 1A chromosome had a terminal 1D segment representing 25% of the length of the recombinant long arm. The translocation was also identified on the long arm using molecular markers, and its length was estimated with a minimum of 91 cM. Proteome analysis was performed on total endosperm proteins. Out of the 152 major spots detected, 9 spots were up-regulated and 4 spots were down-regulated. Most of these proteins were identified as alpha-, beta-, gamma-gliadins assigned to the chromosomes of homoeologous groups 1 and 6. Quantitative variations in the HMW-GS were only observed in subunit Dy12 in response to duplication of the Glu-D1 locus.

Time division multiplexing based method for compressing ECG signals: application for normal and abnormal cases

The proposed ECG compression method combines three major approaches based on time division multiplexing (TDM) and multilevel wavelet decomposition followed by parametrical modelling. Before applying these techniques, a pre-processing step is required, which consists of detecting and aligning different beats. Even though this compression method is regarded as a lossy method, we will show how a high compression ratio (CR) can be achieved by preserving the major medical information within the ECG. Several normal and abnormal signals from various databases are used to evaluate the performance of the proposed technique.

[Quantification of right ventricular function by 2D speckle imaging and three dimensional echography. Comparison with MRI]

PURPOSE

The echocardiographic assessment of right ventricular (RV) function requires many different parameters. We studied and compared with magnetic resonance imaging (MRI) two markers of RV function derived from new imaging tools: 2D speckle imaging (2DSI) and three dimensional echography.

METHODS AND RESULTS

Thirty-two patients (19 with RV ejection fraction [RVEF]< or =45%) underwent both complete echocardiography--including standard parameters of RV function (fractional area change [FAC], Tei index, systolic velocity of tricuspid annulus by DTI), 3D full-volume acquisition on RV--and MRI for the evaluation of RV volumes and RVEF. 2DSI was applied to high frame rate cine loops centred on the RV free wall with measurement of peak systolic strain (%) in the basal, median and apical segments of this wall. Strain, especially in RV median and apical segments, is reduced in patients with RVEF less or equal to 45% (median strain: -16.39+/-5.27 vs. -24.74+/-8.00 [p=0.002]; apical strain -13.01+/-6.84 vs. 22.53+/-11.32 [p=0.03]) with a very good correlation with RVEF (r=-0.717, p=0.0001) but also with the usual echographic parameters of RV function, (FAC: r=0.019; Tei: r=0.01; peak systolic velocity: r=0.002). The 3D RVEF is also but poorly correlated with MRI RVEF, (r=0.447, p=0.017). Furthermore, 3D significantly underestimated RV volumes. By multivariate analysis, apical strain (p=0.004) and FAC (p=0.029) were predictive of a decreased RVEF.

CONCLUSION

Apical strain as measured from 2DSI seems a promising parameter in the estimation of RV function. 3D estimation of RVEF is more disappointing because of an important underestimation of RV volumes.

[Long-term clinical benefits of using active stents in diabetic patients: two year follow-up of a consecutive series of 122 patients]

The objective of our study is to evaluate the long-term results of coronary angioplasty using active stents in a population of diabetic patients. This is a single-centre study on a consecutive series of 122 diabetic patients (40% of them insulin dependent) who between January 2003 and June 2004 underwent angioplasty with implantation of an active stent (sirolimus Cypher(R) or paclitaxel Taxus(R)) for one or more de novo coronary lesions. The mean age was 66 +/- 10 years and a total of 171 coronary segments were treated. The lesions treated were complex (type B2 + C) in 69% of the cases, with a mean stent length of 21 +/- 15 mm and a mean stent diameter of 2.7 +/- 0.3 mm. Follow-up at two years for 119 patients (3 lost to follow-up) revealed a mortality rate of 4.2%, and a myocardial infarction rate of 7.5%. The rates for revascularisation of the target lesion and the target vessel were 11.4% and 17.8% respectively, with a rate of major cardiac events of 22.5%. During this period, 25.2% of the patients underwent revascularisation of at least one vessel. This study confirms the benefits of using active stents for revascularisation of the target lesion in diabetic patients. However, it serves as a reminder that the progression of coronary atheroma is global, and that the prognosis for these patients depends essentially upon managing risk factors, and particularly on controlling their diabetes.

[Mycotic coronary aneurysm with Escherichia coli sepsis: a case report]

We report the case of a patient who was admitted for acute coronary syndrom associated with fever originating from urinary tract. Coronary arteriography revealed a huge coronary aneurysm which ruptured a short time after diagnosis. After surgery, it was proven to be mycotic aneurysm related to Escherichia Coli sepsis.

Drop foot after high tibial osteotomy: a prospective study of aetiological factors

Drop foot is not uncommon after high tibial osteotomy for genu varum. The authors report their results of a prospective study of 16 patients operated on between May 1990 and May 1991. All patients had medial femoro-tibial osteoarthritis with a constitutional genu varum. They all had a subtraction valgus high tibial osteotomy fixed by a blade plate. The experimental protocol included clinical review, antero-lateral compartment pressure measurements, intra- and post-operative electromyography, assessment of the post-operative drainage, serum estimation of muscle enzymes and post-operative arteriography. From their own results and a literature review, the authors consider successively the different aetiological factors for post-operative drop foot. Certain deficits occur due to direct trauma on the nerve during high osteotomy of the fibula, by local high pressure due to poor haemostasis or ineffective drainage. In addition, there are several related phenomena. The pneumatic tourniquet sensitises the nerve to trauma, and stretching of the nerve during correction of the deformation depends on the local anatomical factors and their marked variation. In order to diminish the frequency of these post-operative complications, the authors suggest limiting the surgical approach, and limiting as far as possible the traumatic manoeuvres on the nerve by using a tibial resection jig, which allows correction without forced manoeuvres. Finally, the authors discuss the benefits of using a pneumatic tourniquet.

[Paroxysmal atrioventricular block due to anticholinesterase therapy]

The authors report a case of paroxysmal syncopal complete atrioventricular block due to anticholinesterase therapy occurring after the first administration. The block was reversible. It is therefore important to exclude this cause of atrioventricular block in the elderly in view of the increasing indications of this therapy.

Association of ATP synthase alpha-chain with neurofibrillary degeneration in Alzheimer's disease

Amyloid deposits and neurofibrillary tangles (NFT) are the two hallmarks that characterize Alzheimer's disease (AD). In order to find the molecular partners of these degenerating processes, we have developed antibodies against insoluble AD brain lesions. One clone, named AD46, detects only NFT. Biochemical and histochemistry analyses demonstrate that the labeled protein accumulating in the cytosol of Alzheimer degenerating neurons is the alpha-chain of the ATP synthase. The cytosolic accumulation of the alpha-chain of ATP synthase is observed even at early stages of neurofibrillary degenerating process. It is specifically observed in degenerating neurons, either alone or tightly associated with aggregates of tau proteins, suggesting that it is a new molecular event related to neurodegeneration. Overall, our results strongly suggest the implication of the alpha-chain of ATP synthase in neurofibrillary degeneration of AD that is illustrated by the cytosolic accumulation of this mitochondrial protein, which belongs to the mitochondrial respiratory system. This regulatory subunit of the respiratory complex V of mitochondria is thus a potential target for therapeutic and diagnostic strategies.

Proteomics of breast cancer for marker discovery and signal pathway profiling

Breast cancer is the most common form of cancer among women and the identification of markers to discriminate tumorigenic from normal cells, as well as the different stages of this pathology, is of critical importance. Two-dimensional electrophoresis has been used before for studying breast cancer, but the progressive completion of human genomic sequencing and the introduction of mass spectrometry, combined with advanced bioinformatics for protein identification, have considerably increased the possibilities for characterizing new markers and therapeutic targets. Breast cancer proteomics has already identified markers of potential clinical interest (such as the molecular chaperone 14-3-3 sigma) and technological innovations such as large scale and high throughput analysis are now driving the field. Methods in functional proteomics have also been developed to study the intracellular signaling pathways that underlie the development of breast cancer. As illustrated with fibroblast growth factor-2, a mitogen and motogen factor for breast cancer cells, proteomics is a powerful approach to identify signaling proteins and to decipher the complex signaling circuitry involved in tumor growth. Together with genomics, proteomics is well on the way to molecularly characterizing the different types of breast tumor, and thus defining new therapeutic targets for future treatment.

Identification of substituted sites on MUC5AC mucin motif peptides after enzymatic O-glycosylation combining beta-elimination and fixed-charge derivatization

A strategy for determination of O-glycosylation site(s) in glycopeptides has been developed using model compounds obtained by enzymatic glycosylation (by human GaNTase-T2 isoform) on peptides derived from the human MUC5AC mucin tandem repeat motif. The beta-elimination-addition reaction (using dimethylamine and concomitantly ethanethiol) on the formerly glycosylated sites through a Michael-type condensation produced efficient deglycosylation with appropriate chemical modification. After N-terminal derivatization by a phosphonium group, peptide sequencing was then carried out by nanospray tandem mass spectrometry experiments. The highly predictable fragmentation pathways of these fixed-charge phosphonium derivatives enable straightforward recognition of glycosylation site(s) based on the mass increment of +44 Da for originally glycosylated threonine compared to the mass of fragments containing nonglycosylated residues.

Identification of N-acetyl-d-glucosamine-specific lectins from rat liver cytosolic and nuclear compartments as heat-shock proteins

Cytosolic and nuclear O-linked N-acetylglucosaminylation has been proposed to be involved in the nuclear transport of cytosolic proteins. We have isolated nuclear and cytosolic N-acetyl-d-glucosamine (GlcNAc)-specific lectins from adult rat liver by affinity chromatography on immobilized GlcNAc and identified these lectins, by a proteomic approach, as belonging to the heat-shock protein (HSP)-70 family (one of them being heat-shock cognate 70 stress protein). Two-dimensional electrophoresis indicated that the HSP-70 fraction contained three equally abundant proteins with molecular masses of 70, 65 and 55 kDa. The p70 and p65 proteins are phosphorylated and are themselves O-linked GlcNAc (O-GlcNAc)-modified. The HSP-70 associated into high molecular mass complexes that dissociated in the presence of reductive and chaotropic agents. The lectin(s) present in this complex was (were) able to recognize cytosolic and nuclear ligands, which have been isolated using wheat germ agglutinin affinity chromatography. These ligands are O-GlcNAc glycosylated as demonstrated by [(3)H]galactose incorporation and analysis of the products released by reductive beta-elimination. The isolated lectins specifically recognized ligands present in both the cytosol and the nucleus of human resting lymphocytes. These results demonstrated the existence of endogenous GlcNAc-specific lectins, identified as HSP-70 proteins, which could act as a shuttle for the nucleo-cytoplasmic transport of O-GlcNAc glycoproteins between the cytosol and the nucleus.

Proteomics of breast cancer for marker discovery and signal pathway profiling

Breast cancer is the most common form of cancer among women and the identification of markers to discriminate tumorigenic from normal cells, as well as the different stages of this pathology, is of critical importance. Two-dimensional electrophoresis has been used before for studying breast cancer, but the progressive completion of human genomic sequencing and the introduction of mass spectrometry, combined with advanced bioinformatics for protein identification, have considerably increased the possibilities for characterizing new markers and therapeutic targets. Breast cancer proteomics has already identified markers of potential clinical interest (such as the molecular chaperone 14-3-3 sigma) and technological innovations such as large scale and high throughput analysis are now driving the field. Methods in functional proteomics have also been developed to study the intracellular signaling pathways that underlie the development of breast cancer. As illustrated with fibroblast growth factor-2, a mitogen and motogen factor for breast cancer cells, proteomics is a powerful approach to identify signaling proteins and to decipher the complex signaling circuitry involved in tumor growth. Together with genomics, proteomics is well on the way to molecularly characterizing the different types of breast tumor, and thus defining new therapeutic targets for future treatment.

Osmoregulated periplasmic glucans of Erwinia chrysanthemi

We report the initial characterization of the osmoregulated periplasmic glucans (OPGs) of Erwinia chrysanthemi. OPGs are intrinsic components of the bacterial envelope necessary to the pathogenicity of this phytopathogenic enterobacterium (F. Page, S. Altabe, N. Hugouvieux-Cotte-Pattat, J.-M. Lacroix, J. Robert-Baudouy and J.-P. Bohin, J. Bacteriol. 183:0000-0000, 2001 [companion in this issue]). OPGs were isolated by trichloracetic acid treatment and gel permeation chromatography. The synthesis of these compounds appeared to be osmoregulated, since lower amounts of OPGs were produced when bacteria were grown in media of higher osmolarities. However, a large fraction of these OPGs were recovered in the culture medium. Then, these compounds were characterized by compositional analysis, high-performance anion-exchange chromatography, matrix-assisted laser desorption mass spectrometry, and (1)H and (13)C nuclear magnetic resonance analyses. OPGs produced by E. chrysanthemi are very heterogeneous at the level of both backbone structure and substitution of these structures. The degree of polymerization of the glucose units ranges from 5 to 12. The structures are branched, with a linear backbone consisting of beta-1,2-linked glucose units to which a variable number of branches, composed of one glucose residue, are attached by beta-1,6 linkages in a random way. This glucan backbone may be substituted by O-acetyl and O-succinyl ester-linked residues.

Proteomic detection of changes in protein synthesis induced by fibroblast growth factor-2 in MCF-7 human breast cancer cells

Fibroblast growth factor-2 (FGF-2) is a potent regulator of breast cancer cell growth through stimulation of tyrosine kinase receptors and activation of the mitogen-activated protein kinase cascade. In the present study, we have investigated changes in protein synthesis induced by FGF-2 stimulation of the prototypic human breast cancer cell line MCF-7. Using high-resolution two-dimensional electrophoresis of (35)S amino acid metabolically labeled proteins and computerized analysis of 2D autoradiograms, we found that four proteins were up-regulated within the first 12 h of FGF-2 stimulation. Mass spectrometry analysis (MALDI-TOF and MS-MS) of tryptic fragments and database searches allowed the identification of these FGF-2-regulated proteins as the heat shock proteins HSP90 and HSP70, the proliferating cell nuclear antigen (PCNA), and the transcriptionaly controlled tumor protein (TCTP). We then analyzed the distribution of these proteins in various cancerous and normal breast epithelial cells. Interestingly, the four FGF-2-regulated proteins were found to be constitutively up-regulated in ras-transfected MCF-7 cells, indicating their relevance to the up-regulation of cellular proliferation. Moreover, HSP90 and PCNA were found at higher levels in cancerous cells than in normal cells. The role of HSP90 was further investigated using the specific inhibitor geldanamycin. We showed that the functionality of HSP90 is strictly required in order to obtain FGF-2 mitogenic stimulation in MCF-7 cells, indicating the crucial role played by this molecular chaperone in the control of breast cancer cell growth. Finally, these results show that proteomic analysis is a valuable method for identifying potential markers or therapeutic targets related to cancer growth.

Proteomic analysis reveals that 14-3-3sigma is down-regulated in human breast cancer cells

The class of molecular chaperones known as 14-3-3 is involved in the control of cellular growth by virtue of its apparent regulation of various signaling pathways, including the Raf/mitogen-activated protein kinase pathway. In breast cancer cells, the sigma form of 14-3-3 has been shown to interact with cyclin-dependent kinases and to control the rate of entry into mitosis. To test for a direct role for 14-3-3 in breast epithelial cell neoplasia, we have quantitated 14-3-3 protein levels using a proteomic approach based on two-dimensional electrophoresis and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF). We show here that 14-3-3sigma protein is strongly down-regulated in the prototypic breast cancer cell lines MCF-7 and MDA-MB-231 and in primary breast carcinomas as compared with normal breast epithelial cells. In contrast, levels of the alpha, beta, delta, or zeta isoforms of 14-3-3 were the same in both normal and transformed cells. The data support the idea that 14-3-3sigma is involved in the neoplastic transition of breast epithelial cells by virtue of its role as a tumor suppressor; as such, it may constitute a robust marker with clinical efficacy for this pathology.

Molecular organization of the alkali-insoluble fraction of Aspergillus fumigatus cell wall

Physical and biological properties of the fungal cell wall are determined by the composition and arrangement of the structural polysaccharides. Cell wall polymers of fungi are classically divided into two groups depending on their solubility in hot alkali. We have analyzed the alkali-insoluble fraction of the Aspergillus fumigatus cell wall, which is the fraction believed to be responsible for fungal cell wall rigidity. Using enzymatic digestions with recombinant endo-beta-1,3-glucanase and chitinase, fractionation by gel filtration, affinity chromatography with immobilized lectins, and high performance liquid chromatography, several fractions that contained specific interpolysaccharide covalent linkages were isolated. Unique features of the A. fumigatus cell wall are (i) the absence of beta-1,6-glucan and (ii) the presence of a linear beta-1, 3/1,4-glucan, never previously described in fungi. Galactomannan, chitin, and beta-1,3-glucan were also found in the alkali-insoluble fraction. The beta-1,3-glucan is a branched polymer with 4% of beta-1,6 branch points. Chitin, galactomannan, and the linear beta-1, 3/1,4-glucan were covalently linked to the nonreducing end of beta-1, 3-glucan side chains. As in Saccharomyces cerevisiae, chitin was linked via a beta-1,4 linkage to beta-1,3-glucan. The data obtained suggested that the branching of beta-1,3-glucan is an early event in the construction of the cell wall, resulting in an increase of potential acceptor sites for chitin, galactomannan, and the linear beta-1,3/1,4-glucan.

The mitogenic signaling pathway for fibroblast growth factor-2 involves the tyrosine phosphorylation of cyclin D2 in MCF-7 human breast cancer cells

Fibroblast growth factor-2 (FGF-2) is mitogenic for the human breast cancer cell line MCF-7; here we investigate some of the signaling pathways subserving this activity. FGF-2 stimulation of MCF-7 cells resulted in a global increase of intracellular tyrosine phosphorylation of proteins, particularly FGF receptor substrate-2, the protooncogene product Src and the mitogen-activated protein kinase (MAP kinase) cascade. A major increase in the tyrosine phosphorylation of a 30-kDa protein species was also found. This protein was identified as cyclin D2 by mass spectrometry after trypsin digestion. Immunoprecipitation of cyclin D2 and immunoblotting with anti-phosphotyrosine antibodies confirmed that the tyrosine phosphorylation of cyclin D2 was indeed induced by FGF-2 stimulation. In addition, pharmacological inhibition of Src (with herbimycin A and PP2), and of the MAP kinase cascade (with PD98059), confirmed that Src activity is required for the FGF-2-induced phosphorylation of cyclin D2 whereas MAP kinase activity is not. Thus, tyrosine phosphorylation of cyclin D2 may be a key regulatory target for FGF-2 signaling.

Evaluation of biohazards in dehydrated biofilms on foodstuff packaging

Plastic materials used for food packaging are clean but not sterile when the food is just packaged. Accidental wet contamination may occur at every moment between packaging and opening by the consumer: on polyethylene (PET), bacteria may adhere strongly and constitute a biofilm in less than 24 h. By rolling on themselves, PET sheets may contaminate food. We tried to show that contact with salted foodstuffs favoured microbial recovery. Four strains were chosen to perform biofilms on PET: Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli. Biofilms were dried up 24 h. Biofilm bacteria were stressed by adhesion, by starvation and by dehydration. However, they were capable of recovery in salted solutions or media, probably because one (or more) stress protected them against another stress. Stress was demonstrated by stress protein production, by mean of electrophoresis, and membrane lesions by mean of flow cytometry. Stress recovery was performed in aqueous salted solutions or salted brain-heart infusion with NaCl 9, 15, 20 and 30 g/l. Staphylococci were more sensitive to these stresses and recovery was a function of salt concentration. Gram-negative bacteria were little affected by stresses; salt effects were less important. If all these biofilms were capable of recovery from stresses in salted media, flexible PET could possibly lead to a health hazard when it is used for wet salt meats, e.g.

Analysis of 8-aminonaphthalene-1,3,6-trisulfonic acid labelled N-glycans by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry

Fluorophore-assisted carbohydrate electrophoresis (FACE) is a fast and efficient analytical method which is now widely used in glycobiology for the separation and quantification of free or glycoprotein-released oligosaccharides. However, since identification by FACE of N-glycan structures is only based on their electrophoretic mobility after labelling with 8-aminonaphthalene-1,3, 6-trisulfonic acid (ANTS), co-migration of derived glycans on gel could occur which may result in erroneous structural assignments. As a consequence, a protocol was developed for the fast and efficient matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometric analysis of ANTS-labelled N-glycans. N-Glycans were isolated from plant and mammalian glycoproteins, reductively aminated with the charged fluorophore 8-aminonaphthalene-1, 3, 6-trisulfonic acid (ANTS) and separated using high resolution polyacrylamide gel electrophoresis. The ANTS-labelled glycans were eluted from FACE gel slices and then analysed by MALDI-TOF mass spectrometry in negative ion mode. Using 3-aminoquinoline containing 2.5 mM citrate NH(4)(+) as matrix, neutral N-linked N-glycans, as well as labelled sialylated oligosaccharides, were found to be easily detected in the 2-10 picomole range giving rise to ¿M - H(-) ions.

Structural analysis of three sulfated oligosaccharides isolated from human milk

The structures of two sulfated octasaccharides and one sulfated nonasaccharide isolated from human milk have been investigated. Using 13C and 1H NMR spectroscopy and ESMS, the following structures 1-3 were established: [formula: see text].

Characterization of N-glycans from Arabidopsis. Application to a fucose-deficient mutant

The structures of glycans N-linked to Arabidopsis proteins have been fully identified. From immuno- and affinodetections on blots, chromatography, nuclear magnetic resonance, and glycosidase sequencing data, we show that Arabidopsis proteins are N-glycosylated by high-mannose-type N-glycans from Man5GlcNAc2 to Man9GlcNAc2, and by xylose- and fucose (Fuc)-containing oligosaccharides. However, complex biantenary structures containing the terminal Lewis a epitope recently reported in the literature (A. -C. Fitchette-Lainé, V. Gomord, M. Cabanes, J.-C. Michalski, M. Saint Macary, B. Foucher, B. Cavalier, C. Hawes, P. Lerouge, and L. Faye [1997] Plant J 12: 1411-1417) were not detected. A similar study was done on the Arabidopsis mur1 mutant, which is affected in the biosynthesis of L-Fuc. In this mutant, one-third of the Fuc residues of the xyloglucan has been reported to be replaced by L-galactose (Gal) (E. Zablackis, W.S. York, M. Pauly, S. Hantus, W.D. Reiter, C.C.S. Chapple, P. Albersheim, and A. Darvill [1996] Science 272: 1808-1810). N-linked glycans from the mutant were identified and their structures were compared with those isolated from the wild-type plants. In about 95% of all N-linked glycans from the mur1 plant, L-Fuc residues were absent and were not replaced by another monosaccharide. However, in the remaining 5%, L-Fuc was found to be replaced by a hexose residue. From nuclear magnetic resonance and mass spectrometry data of the mur1 N-glycans, and by analogy with data reported on mur1 xyloglucan, this subpopulation of N-linked glycans was proposed to be L-Gal-containing N-glycans resulting from the replacement of L-Fuc by L-Gal.

Identification of urinary oligosaccharides by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

A new method of urinary oligosaccharides identification by matrix-assisted laser desorption time-of-flight mass spectrometry is presented. The method involves three steps: coupling of the urinary oligosaccharides with 8-aminonaphthalene-1,3,6-trisulfonic acid; fast purification over a porous graphite carbon extraction column; and mass spectrometric analysis. Identification of urinary oligosaccharides is based on the patterns and values of the pseudomolecular ions observed. We report here the patterns in urines from patients with Pompe disease, alpha and beta mannosidoses, galacto-sialidosis, and GM1 gangliosidosis. The protocols described here allowed facile and sensitive identification of the pathognomonic oligosacchariduria present in lysosomal diseases and can be extended to any pathological oligosacchariduria.

Two novel isoneolacto-undecaglycosylceramides carrying Galalpha1-->3Lewis(x) on the 6-linked antenna and N-acetylneuraminic acidalpha2-->3 or Galactose alpha1-->3 on the 3-linked antenna, expressed in porcine kidney

Three sialosylated and three neutral glycosphingolipids sharing a common iso-neolacto core were isolated from porcine kidney cortex. They were purified by preparative HPTLC, and were characterized by partial exoglycosidase hydrolysis followed by thin layer chromatography and immunostaining with anti-Galalpha1-->3Gal, anti-type 2 lactosamine and anti-Lewis(x) antibodies, methylation analysis, MALDI-TOF mass spectrometry and 1H-NMR spectroscopy. Among neutral glycolipids, one was a known structure, VI3VI'3(alphaGal)2-iso-nLc8Cer, and two were novel structures differing by the number of Galalpha3Lewis(x) determinants: VI3VI'3(alphaGal)2V'3alphaFuc-iso-nLc8, and VI3VI'3(alphaGal)2 V3V'3(alphaFuc)2-iso-nLc8. The single Galalpha3Lewis(x) determinant was found on the 6-linked antenna. Among sialosylated glycolipids, two had been previously found in other species and tissues, VI3VI'3(NeuAc)2-iso-nLc8, and VI3NeuAcVI'3alphaGal-iso-nLc8. A novel structure was discovered presenting a Galalpha3Lewis(x) determinant on the 6-linked antenna and a N-acetylneuraminic acid on the 3-linked antenna, VI3NeuAcVI'3alphaGalV'3alphaFuc-iso-nLc8. These results indicate that, in vivo, the porcine kidney alpha3fucosyltransferase synthesizes the Gala3Lewis(x) determinant, acting on the 6-linked before the 3-linked Galalpha3neolactosamine, and appears unable to synthesize the sialosylated Lewis(x) determinant on neolactoseries glycolipids.

Structural analysis of O-linked oligosaccharide-alditols by electrospray-tandem mass spectrometry after mild periodate oxidation and derivatization with 2-aminopyridine

O-linked oligosaccharide-alditols were analyzed by a combination of high-performance liquid chromatography (HPLC) and electrospray-tandem mass spectrometry (ESI-MS/MS). First, oligosaccharide-alditols were treated with sodium meta-periodate under conditions where core N-acetylgalactosaminitol is specifically degraded. The resulting fragments were labeled with 2-aminopyridine and purified on a reversed-phase column. Pyridylamino oligosaccharides yielded protonated molecular ions in positive-ion ES-MS and gave Y-series sequence ions, arising from glycosidic cleavages, by ESI-tandem mass spectrometry. Information on sugar sequence and branching of oligosaccharides linked at C6 and C3 to the N-acetylgalactosaminitol can be obtained. A systematic study of various oligosaccharide-alditols demonstrated that this approach constitutes a powerful tool for the structural characterization of O-glycans available only in limited quantities.

[Orthopedic treatment of fractures of the lower extremity of the radius by the Judet technique. Anatomic results in function of the type of lesion: apropos of 280 cases]

PURPOSE OF THE STUDY

The authors evaluated the anatomical results and limits of the conservative treatment for displaced Colle's fracture.

MATERIAL AND METHODS

The anatomical results of 280 consecutive fractures were retrospectively analysed. Conservative treatment was performed according to Judet. Stability of the reduction was assessed for grade 0, 1, 2 of Kapandji's classification. Radiographical mean follow-up for all patient was three months (2 months to 8 years).

RESULTS

In 122 cases (64 per cent) mal-union was observed. Mal-union was due in 93.5 per cent of cases (114) to secondary displacement of the distal fragment and in 6.5 per cent (8 cases) to poor reduction. Secondary displacement was essentially posterior in the sagittal plane. The principal factors of instability were radial shortening superior to 3 mm (p = 0.005), patient age of 55 years of more (p = 0.004), metaphyseal comminution (p = 0.004) and degree of primary displacement in the frontal plane (p = 0.01). Stability after reduction was determined by crossing the distal fragment in relation to the anterior cortex of the proximal fragment. There were 10.5 per cent algodystrophies and 9 per cent median nerve paresthesiae which were avoided by 45 degrees of wrist flexion.

DISCUSSION

Judet's conservative treatment is indicated in extra-articular Colle's fractures (grade 0, 1, 2 of Kapandji's classification), after evaluation of factors of instability, secondary displacement and mal-union. Minor mal-unions may be well tolerated, and do not seem to affect wrist function with 3 mm of radial shortening and 10 degrees of radial glenoid posterior angulation on the sagittal plane.

Purification and characterization of the MUC1 mucin-type glycoprotein, epitectin, from human urine: structures of the major oligosaccharide alditols

The MUC1 glycoprotein, epitectin, a component of the human bladder epithelium, was purified from human urine. Sedimentation equilibrium analysis and gel filtration using polysaccharide or protein standards revealed a polydisperse preparation with molecular weights ranging from about 0.9 to 1.3 x 10(6). This suggests that in the native state epitectin exists as aggregates of three or four monomer units of 350-400 kDa. Epitectin was found to have significant affinity to hexyl-, octyl- or phenyl agarose indicating that hydrophobic interactions and possibly carbohydrate-carbohydrate interactions may be responsible for the self-association. Chemical and enzymic deglycosylation of [125I]-labeled urine epitectin and metabolically labeled H.Ep.2 epitectin resulted in extremely polydisperse products. The buoyant densities of epitectin purified from urine and H.Ep.2 cells were found to be 1.39-1.40 g ml(-1), suggesting that the total carbohydrate content of these preparations is not significantly different. The O-linked saccharides of epitectin were fractionated by HPLC and analyzed by permethylation and FAB-MS. The neutral saccharides from both sources contain three common structures, namely Gal1 --> 3GalNAc, GlcNAc1 --> 6 (Gal1 --> 3) GalNAc and Gal1 --> 4GlcNAc --> 6 (Gal1 --> 3)GalNAc. The sialic acid of urine epitectin consisted entirely of N-acetylneuraminic acid. The two sources of epitectin, in vitro labeled on sialic acid, were found to have the same sialyl oligosaccharides but in different proportions. Metabolic labeling and N-glycanase susceptibility experiments firmly established the presence of N-linked saccharides in epitectin as minor components. The remarkable similarities in the total carbohydrate content, the carbohydrate composition and structures of saccharides between epitectin from urine, a non-malignant source, and H.Ep.2 cells is surprising in view of the prevailing view that MUC1 glycoproteins of cancer cells are underglycosylated compared to those produced by non-malignant cells.

Sulfated lewis X determinants as a major structural motif in glycans from LS174T-HM7 human colon carcinoma mucin

This article describes oligosaccharide structures of mucin isolated from nude mouse xenograft tumors produced by LS174T-HM7 cells, a subline of the human colon carcinoma LS174T with higher metastatic tendency and higher mucin production. A striking feature of the oligosaccharides of the LS174T-HM7 xenograft tumor mucin was a predominance of sulfated Lewis X determinants: HSO3-Galbeta1-4(Fucalpha1-3)GlcNAc. In addition to one previously known saccharide with one sulfated Lewis X determinant, the HM7 xenograft tumor mucin contained multiple novel structures containing one, two, or three sulfated Lewis X determinants. This determinant, known to act as a selectin ligand, has been found previously in minor saccharide components of human milk as well as mucins, but never before as a predominant structure in one mucin source.

Structural characterization of the exocellular polysaccharides produced by Streptococcus thermophilus SFi39 and SFi12

We investigated the structures of the exopolysaccharides (EPSs) produced by Streptococcus thermophilus SFi39 and SFi12. Both polymers were found to have molecular masses of greater than 2 x 10(6) Da. The SFi39 EPS consisted of D-glucose and D-galactose in a molar ratio of 1:1, whereas the SFi12 EPS was composed of D-galactose, L-rhamnose, and D-glucose in a molar ratio of 3:2:1. Methylation analysis of and nuclear magnetic resonance spectra recorded from the native polysaccharide, as well as oligosaccharides released by partial acid hydrolysis, allowed the complete structural determination of the SFi39 EPS, which consists of the following tetrasaccharide repeating unit: [formula: see text] Similar spectra recorded only from the native polysaccharide were sufficient to allow the structural determination of the SFi12 EPS, which consists of the following hexasaccharide repeating unit: [formula: see text] This study shows that the texturizing properties of different S. thermophilus ropy strains are based on the production of EPSs exhibiting chemical similarities but structural differences.

Lactobacillus helveticus Lh59 secretes an exopolysaccharide that is identical to the one produced by Lactobacillus helveticus TN-4, a presumed spontaneous mutant of Lactobacillus helveticus TY1--2

Lactobacillus helveticus Lh59 produces a high-molecular-mass exopolysaccharide (> or = 2 x 10(6) Da) when cultured in skimmed milk. Compositional analysis, methylation analysis and NMR experiments (1H and 13C) recorded from the native polysaccharide as well as from oligosaccharides released by partial acid hydrolysis, allowed the complete structural determination of this polysaccharide, which consists of the following hexasaccharide repeating unit: [symbol: see text] This structure is identical to the one of an EPS produced by L. helveticus TN-4, which was claimed to be a spontaneous mutant of strain TY1-2.

Structural analysis of the oligosaccharide-alditols released by reductive beta-elimination from oviducal mucins of Rana temporaria

The carbohydrate chains of the mucins which constitute the jelly coat surrounding the eggs of Rana temporaria were released by alkaline borohydride treatment. Neutral and acidic oligosaccharide-alditols were purified by ion-exchange chromatography and HPLC. From the structural analysis, based upon 1H and 13C-NMR spectroscopy in combination with MALDI-TOF, the following glycan units are proposed.

Structural analysis of derivatized oligosaccharides using post-source decay matrix-assisted laser desorption/ionization mass spectrometry

Structural information on oligosaccharides was obtained by post-source decay matrix-assisted laser desorption/ionization mass spectrometry. A systematic study of derivatized oligosaccharides showed that products relatively aminated with benzylamine allow the formation of [M+H]+ molecular species. Metastable protonated species decompose in the field-free region (post-source decay) to yield predictable and reproducible fragmentation patterns. Information on sugar sequence and branching can be derived from such mass spectra.

Sialylation and sulfation of the carbohydrate chains in respiratory mucins from a patient with cystic fibrosis

Mucin glycopeptides were prepared from the sputum of a patient suffering from cystic fibrosis. The carbohydrate chains were released by alkaline borohydride treatment. Sialylated and sulfated oligosaccharide-alditols were purified by ion-exchange chromatography, gel filtration, and high performance anion-exchange chromatography. The structures of the oligosaccharide-alditols were determined by high resolution 1H NMR spectroscopy in combination with fast atom bombardment-mass spectrometry. Twenty-four oligosaccharides were characterized and illustrate the diversity of the carbohydrate chains of cystic fibrosis respiratory mucins. Among these 24 oligosaccharide-alditols, 15 are novel structures. Sialylation may occur on the C-6 of the N-acetylgalactosamine involved in the carbohydrate-peptide linkage or on a terminal galactose residue, either on C-3 or on C-6. Sulfation may occur either on the C-3 of a terminal galactose residue or on the C-6 of a N-acetylglucosamine residue. The most complex structures contain sulfated derivatives of the H,X, or Y determinants or a sialylated and sulfated derivative of the X determinant (Structure A).