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B Schweitzer

Publications and source records attributed to B Schweitzer.

At least 19 recordsLinked to original sources
PubMed2006

Relationships of physical activity with metabolic syndrome features and low-grade inflammation in adolescents.

AIMS/HYPOTHESIS: Physical activity has beneficial effects on symptoms of the metabolic syndrome and low-grade inflammation in adults. These associations have rarely been studied in adolescents. Moreover, it has not been established whether they depend on adiposity, fat localisation and adipokines. SUBJECTS, MATERIALS AND METHODS: We used cross-sectional data of 640 12-year-old adolescents participating in the Intervention Centred on Adolescents' Physical Activity and Sedentary Behaviour Study (ICAPS). Weight, height, body fat mass and WHR were measured. Metabolic syndrome components, two inflammatory markers (IL-6 and C-reactive protein), plasma leptin, adiponectin and soluble TNF-alpha receptor 1 (sTNF-alpha R1) were determined. Insulin resistance was estimated by homeostasis model assessment (HOMA) and energy expenditure due to organised leisure-time physical activity (PAE) assessed by questionnaire. RESULTS: The metabolic syndrome was present in 5.8% of the adolescents. After adjustment for sex, sexual maturity and socio-economic status, a beneficial relationship between PAE and all metabolic syndrome features was found, but only the associations with HOMA and IL-6 were independent of body fat mass and WHR. Adjusted means from the lowest to the highest tertile of PAE were 1.99, 1.80 and 1.78 for HOMA (p=0.04), and 0.88, 0.69 and 0.70 pg/ml for IL-6 (p=0.02). PAE was inversely associated with leptin, independently of body fat mass and WHR (p<10(-2)), but not with adiponectin or sTNF-alpha R1. Further adjustment for adipokines did not change the relationships of PAE with HOMA and IL-6. CONCLUSIONS/INTERPRETATION: In adolescents, physical activity is inversely related to HOMA and IL-6, independently of adiposity and fat localisation. These relationships are not accounted for by adipokines.

Adipocytes↗
PubMed2006

ICAPS: a multilevel program to improve physical activity in adolescents.

OBJECTIVES: ICAPS (Intervention Centred on Adolescents' Physical activity and Sedentary behaviour) is aimed at preventing excessive weight gain and cardiovascular risk in adolescents by promoting physical activity (PA) with an emphasis on recreational and daily-life PA, with a lifelong perspective. DESIGN: Randomized study designed to last for four years. Study cohort constituted of 954 first-level students (91% of eligible pupils), aged 11.7 +/- 0.6 y (mean +/- SD) from four pairs of schools randomly selected in eastern France, after sociogeographical stratification. In each pair, intervention status was randomised at school-level. The program, not limited to school settings, involves multiple partners with three objectives: 1) changing attitudes through debates and access to attractive activities during breaks and after-school hours, 2) encouraging social support, 3) providing environmental conditions that enable PA. Adapted times and places, open participation, emphasis on fun, meeting with others and absence of competitive aspects are used to reduce usual barriers to PA. Accessibility and safety are permanent concerns. RESULTS: Prevalence of overweight was 23.7%. High participation rates were attained (50% participated in at least one weekly activity). At six-month, the proportion of intervention adolescents not performing supervised PA out of academic PA was reduced by half (36% to 17% vs 42% to 42% in controls P < 10-4); the proportion of those spending > 3 h/day in sedentary occupations decreased (34% to 28% vs 27% to 36%; P < 10-4). CONCLUSION: These data demonstrate the feasibility of implementing a multilevel PA intervention program in adolescents. Six-month results document increased PA and decreased sedentary behaviour.

Adolescent↗
PubMed2004

[Relationship between asthma or asthma-related symptoms and school problems among French children attending kindergarden].

BACKGROUND: The impact of chronic respiratory symptoms on school performance has been studied less than its impact on children's health. Our survey explored the relationship between chronic respiratory symptoms and school problems among children attending kindergarten. It assessed the impact of school absenteeism, sport practise in a club and health care access for school problems among pupils with chronic respiratory symptoms. METHODS: A population-based study was carried out by school physicians on a representative sample of pupils attending third-year kindergarten, in Alsace - France. Assessments included school problems, sociodemographic and health care access characteristics. Health conditions, notably chronic respiratory symptoms, were asked to include the pupils in one of the three study groups: physician-diagnosed asthma, asthma-related symptoms not associated with diagnosed asthma, and without current health problems (controls). Logistic regression was used to compare the odds ratio of school problems for the three study groups, overall and stratified by income. RESULTS: The 2,632 included pupils aged 5 to 6 Years, were assigned to the three groups according to their respiratory status: 179 with diagnosed asthma, 176 with asthma related symptoms and 2,277 healthy pupils. Diagnosed asthma was not linked with school problems. The overall association between asthma related symptoms and school problems was significant (OR=1.5, 95% CI: 1.0-2.2). After adjustment, this association persisted among pupils whose mother's education level was intermediary (technical or vocational diploma) (OR=2.3, 95% CI: 1.2-4.6). Among the diagnosed asthma group, pupils practising a sport in a club had less school problems than those not taking part in sports (ORadjusted=0.2, 95% CI: 0.03-0.8). CONCLUSION: In our study, asthmatic children were not at higher risk of school problems. So developing programs preventing school problems which focus on asthmatic children is not needed. Among the pupils having a mother with an intermediary education level, asthma-related symptoms were associated with school problems. It is important to identify unknown asthmatics to institute to treatment for their respiratory symptoms in order to prevent the consequences of the functional impact of asthma on their scholarship.

Absenteeism↗
PubMed2004

Intervention centred on adolescents' physical activity and sedentary behaviour (ICAPS): concept and 6-month results.

OBJECTIVE: To evaluate the 6-month impact of a physical activity (PA) multilevel intervention on activity patterns and psychological predictors of PA among adolescents. The intervention was directed at changing knowledge and attitudes and at providing social support and environmental conditions that encourage PA of adolescents inside and outside school. SUBJECTS AND DESIGN: Randomised, controlled ongoing field trial (ICAPS) in middle-school's first-level adolescents from eight schools selected in the department of the Bas-Rhin (Eastern France) with a cohort of 954 adolescents (92% of the eligible students) initially aged 11.7+/-0.6 y. The 6-month changes in participation in leisure organised PA (LOPA), high sedentary (SED) behaviour (>3 h/day), self-efficacy (SELF) and intention (INTENT) towards PA were analysed after controlling for baseline measures and different covariables (age, overweight, socioprofessional occupation), taking into account the cluster randomisation design. RESULTS: The proportion of intervention adolescents not engaged in organised PA was reduced by 50% whereas it was unchanged among control students. After adjustment for baseline covariables, LOPA participation significantly increased among the intervention adolescents (odds ratio (95% confidence interval) (OR)=3.38 (1.42-8.05) in girls; 1.73 (1.12-2.66) in boys), while high SED was reduced (OR=0.54 (0.38-0.77) in girls; 0.52 (0.35-0.76) in boys). The intervention improved SELF in girls, whatever their baseline LOPA (P<10(-4)) and INTENT in girls with no baseline LOPA (P=0.04). SELF tended to improve in boys with no baseline LOPA, without reaching statistical significance. When included in the regression, follow-up LOPA was associated with improvement of SELF in girls (P=0.02) and of INTENT in girls with no baseline PA (P<0.02). The intervention effect was then attenuated. CONCLUSION: After 6 months of intervention, ICAPS was associated with a significant improvement of activity patterns and psychological predictors, indicating a promising approach for modifying the long-term PA level of adolescents.

Adolescent↗
PubMed2001

Signal amplification by rolling circle amplification on DNA microarrays.

While microarrays hold considerable promise in large-scale biology on account of their massively parallel analytical nature, there is a need for compatible signal amplification procedures to increase sensitivity without loss of multiplexing. Rolling circle amplification (RCA) is a molecular amplification method with the unique property of product localization. This report describes the application of RCA signal amplification for multiplexed, direct detection and quantitation of nucleic acid targets on planar glass and gel-coated microarrays. As few as 150 molecules bound to the surface of microarrays can be detected using RCA. Because of the linear kinetics of RCA, nucleic acid target molecules may be measured with a dynamic range of four orders of magnitude. Consequently, RCA is a promising technology for the direct measurement of nucleic acids on microarrays without the need for a potentially biasing preamplification step.

Alleles↗
PubMed2001

SpL201: a conditionally immortalized Schwann cell precursor line that generates myelin.

Dramatic progress has been made over recent years toward the elucidation of the mechanisms regulating lineage determination and cell survival in the developing peripheral nervous system. However, our understanding of Schwann cell development is limited. This is partly due to the difficulties in culturing primary Schwann cell precursor cells, the earliest developmental stage of the Schwann cell lineage defined to date. Both the inability to maintain cultured Schwann cell precursor cells in an undifferentiated state and the technical difficulties involved in their isolation have hampered progress. We have conditionally immortalized rat Schwann cell precursor cells using a retrovirally encoded EGFR/neu fusion protein to circumvent these problems and to generate a source of homogeneous cells. The resulting SpL201 cell line expresses p75 and nestin, two proteins expressed by neural crest-derived cells, as well as peripheral myelin protein 22, protein zero, and Oct-6 as markers of the Schwann cell lineage. When cultured in EGF-containing medium, the SpL201 cells proliferate and maintain an undifferentiated, Schwann cell precursor cell-like state. The cell line is dependent on EGF for survival but can differentiate into early Schwann cell-like cells in response to exogenous factors. Like primary rat Schwann cells, SpL201 cells upregulate Oct-6 and myelin gene expression in response to forskolin treatment. Furthermore, the SpL201 cell line can form myelin in the presence of axons in vitro and is capable of extensively remyelinating a CNS white matter lesion in vivo. Thus, this cell line provides a valuable and unique tool to study the Schwann cell lineage, including differentiation from the Schwann cell precursor cell stage through to myelination.

Animals↗
PubMed2001

Rolling circle amplification: a new approach to increase sensitivity for immunohistochemistry and flow cytometry.

Immunohistochemistry is a method that can provide complementary diagnostic and prognostic information to morphological observations and soluble assays. Sensitivity, specificity, or requirements for arduous sample preparation or signal amplification procedures often limit the application of this approach to routine clinical specimens. Rolling circle amplification (RCA) generates a localized signal via an isothermal amplification of an oligonucleotide circle. The application of this approach to immunohistochemistry could extend the utility of these methods to include a more complete set of immunological and molecular probes. RCA-mediated signal amplification was successfully applied to the sensitive and specific detection of a variety of cell surface antigens (CD3, CD20, and epithelial membrane antigen) and intracellular molecules (vimentin and prostate-specific antigen) within a variety of routinely fixed specimens, as well as samples prepared for flow cytometry. RCA technology, which has an intrinsically wide dynamic range, is a robust and simple procedure that can provide a universal platform for the localization of a wide variety of molecules as a function of either antigenicity or nucleic acid sequence. The use of RCA in this way could enhance the use of markers of current interest as well as permit the integration of emerging information from genomics and proteomics into cell- and tissue-based analyses.

Antibodies, Monoclonal↗
PubMed2001

Combining nucleic acid amplification and detection.

Major recent advances in molecular amplification in the past year were initial validation of two new amplification technologies (rolling circle amplification and Invader), a significant increase in the number of molecular diagnostic assays, achievement of amplification directly on microarrays (by strand displacement amplification and rolling circle amplification), and description of two new read-out probes (Scorpions and nanoparticles).

DNA, Circular↗
PubMed2001

Alpha- and beta-Proteobacteria control the consumption and release of amino acids on lake snow aggregates.

We analyzed the composition of aggregate (lake snow)-associated bacterial communities in Lake Constance from 1994 until 1996 between a depth of 25 m and the sediment surface at 110 m by fluorescent in situ hybridization with rRNA-targeted oligonucleotide probes of various specificity. In addition, we experimentally examined the turnover of dissolved amino acids and carbohydrates together with the microbial colonization of aggregates formed in rolling tanks in the lab. Generally, between 40 and more than 80% of the microbes enumerated by DAPI staining (4',6'-diamidino-2-phenylindole) were detected as Bacteria by the probe EUB338. At a depth of 25 m, 10.5% +/- 7.9% and 14.2% +/- 10.2% of the DAPI cell counts were detected by probes specific for alpha- and beta-Proteobacteria. These proportions increased to 12.0% +/- 3.3% and 54.0% +/- 5.9% at a depth of 50 m but decreased again at the sediment surface at 110 m to 2.7% +/- 1.4% and 41.1% +/- 8.4%, indicating a clear dominance of beta-Proteobacteria at depths of 50 and 110 m, where aggregates have an age of 3 to 5 and 8 to 11 days, respectively. From 50 m to the sediment surface, cells detected by a Cytophaga/Flavobacteria-specific probe (CF319a) comprised increasing proportions up to 18% of the DAPI cell counts. gamma-Proteobacteria always comprised minor proportions of the aggregate-associated bacterial community. Using only two probes highly specific for clusters of bacteria closely related to Sphingomonas species and Brevundimonas diminuta, we identified between 16 and 60% of the alpha-Proteobacteria. In addition, with three probes highly specific for close relatives of the beta-Proteobacteria Duganella zoogloeoides (formerly Zoogloea ramigera), Acidovorax facilis, and Hydrogenophaga palleroni, bacteria common in activated sludge, 42 to 70% of the beta-Proteobacteria were identified. In the early phase (<20 h) of 11 of the 15 experimental incubations of aggregates, dissolved amino acids were consumed by the aggregate-associated bacteria from the surrounding water. This stage was followed by a period of 1 to 3 days during which dissolved amino acids were released into the surrounding water, paralleled by an increasing dominance of beta-Proteobacteria. Hence, our results show that lake snow aggregates are inhabited by a community dominated by a limited number of alpha- and beta-Proteobacteria, which undergo a distinct succession. They successively decompose the amino acids bound in the aggregates and release substantial amounts into the surrounding water during aging and sinking.

Alphaproteobacteria↗
PubMed2000

Immunoassays with rolling circle DNA amplification: a versatile platform for ultrasensitive antigen detection.

We describe an adaptation of the rolling circle amplification (RCA) reporter system for the detection of protein Ags, termed "immunoRCA. " In immunoRCA, an oligonucleotide primer is covalently attached to an Ab; thus, in the presence of circular DNA, DNA polymerase, and nucleotides, amplification results in a long DNA molecule containing hundreds of copies of the circular DNA sequence that remain attached to the Ab and that can be detected in a variety of ways. Using immunoRCA, analytes were detected at sensitivities exceeding those of conventional enzyme immunoassays in ELISA and microparticle formats. The signal amplification afforded by immunoRCA also enabled immunoassays to be carried out in microspot and microarray formats with exquisite sensitivity. When Ags are present at concentrations down to fM levels, specifically bound Abs can be scored by counting discrete fluorescent signals arising from individual Ag-Ab complexes. Multiplex immunoRCA also was demonstrated by accurately quantifying Ags mixed in different ratios in a two-color, single-molecule-counting assay on a glass slide. ImmunoRCA thus combines high sensitivity and a very wide dynamic range with an unprecedented capability for single molecule detection. This Ag-detection method is of general applicability and is extendable to multiplexed immunoassays that employ a battery of different Abs, each labeled with a unique oligonucleotide primer, that can be discriminated by a color-coded visualization system. ImmunoRCA-profiling based on the simultaneous quantitation of multiple Ags should expand the power of immunoassays by exploiting the increased information content of ratio-based expression analysis.

Animals↗
PubMed2000

Phosphorescence of pi-conjugated oligomers and polymers.

We observed phosphorescence from a ladder-type poly-(para-phenylene) and an analogous oligomer containing five phenylene rings. The spectra are similar to the intrinsic fluorescence spectra and bear out a singlet-triplet splitting of 5000 cm(-1) (polymer) and 6800 cm(-1) (oligomer). Phosphorescence decay of the polymer occurs on a 10-100-micros scale obeying a power law and suggestive of nonradiative quenching, while that of the oligomer is asymptotically exponential with an intrinsic decay time of approximately 250 ms. The polymer also exhibits delayed fluorescence. It originates from delayed recombination of geminate electron-hole pairs rather than from triplet-triplet annihilation.

Journal Article↗
PubMed2000

Platelet-derived growth factor-BB supports the survival of cultured rat Schwann cell precursors in synergy with neurotrophin-3.

To understand the intimate axon-Schwann cell relationship required for the accurate development and regeneration of the peripheral nervous system (PNS), it is important to elucidate the repertoire of growth factors involved in this tightly regulated bi-directional dialogue. We focused on the identification and functional characterization of receptor tyrosine kinases (RTKs) in Schwann cells to gain insights into the corresponding growth factor ligands, which may be regulating the highly controlled differentiation of the Schwann cell lineage. Using an RT-PCR based differential display approach, we have identified 17 tyrosine kinases in embryonic rat sciatic nerves during the crucial transition from Schwann cell precursors to early Schwann cells. In this study, we have examined the expression and function of TrkC and the platelet-derived growth factor (PDGF) receptors alpha and beta on Schwann cell precursor cells. These receptors are expressed on freshly isolated Schwann cell precursors, and we show that PDGF-BB is able to rescue a subpopulation of these cells from apoptotic cell death in vitro. Furthermore, the TrkC-ligand neurotrophin-3 (NT-3) can act synergistically to potentiate this effect. However, PDGF-BB and NT-3 do not induce Schwann cell precursor proliferation or differentiation. Our data are consistent with a model suggesting that a combination of growth factors that include PDGF-BB and NT-3 are acting in concert and in synergy to regulate early Schwann cell development.

Animals↗
PubMed1999

Effective gene transfer of lacZ and P0 into Schwann cells of P0-deficient mice.

Mutations in the gene encoding for the myelinating Schwann cell protein P0 have been linked to inherited peripheral neuropathies, including the Charcot-Marie-Tooth type 1B disease (CMT1B) and Dejerine-Sottas syndrome (DSS). Recently generated mice deficient in the P0 gene (P0-/- mice) resemble cases of CMT1B and DSS with impaired myelin dosage (Martini et al., 1995a). Potential approaches to treat such diseases include the introduction of the normal gene in the nerves of strongly affected patients. In the present study we used P0-/- mice to evaluate the efficiency of a replication-defective, E1-deleted adenovirus vector carrying the lacZ (Ad-RSV-lacZ) or P0 (Ad-RSV-P0) gene to infect abnormally myelinating Schwann cells. The Ad-RSV-lacZ vector suspension was injected into the left sciatic nerve ofPO-/- mice and the nerves examined for beta-galactosidase activity by X-gal histochemistry. Contralateral nerves injected with vehicle solution or non-injected served as controls. Beta-galactosidase activity was detected in nerves injected with the Ad-RSV-lacZ vector up to 2 weeks post-injection. Immunosuppressing the mice with FK506 to decrease the infiltration of activated T-cells in infected nerves lengthened beta-galactosidase activity to 8 weeks, the longest time point examined. Ultrastructural analysis indicated that X-gal crystals were present mostly in abnormally myelinating Schwann cells. These findings demonstrate that an adenovirus vector can successfully infect Schwann cells in P0-/- mice and expression can be maintained for several weeks. The Ad-RSV-P0 suspension was then injected in the sciatic nerve of immunosuppressed P0-/- mice. Two and four weeks post-injection both P0 mRNA and protein could be detected by in situ hybridization and Western blotting in some of the nerves. Furthermore, P0 protein expression was observed in myelin-like structures and onion bulb-like cells by immunohistochemistry. These results indicate that Schwann cells in P0-/- mice can be induced to produce P0 protein after gene transfer. Genetic repair of abnormal Schwann cells by using adenovirus vectors might be a possible technique to treat animal models of inherited peripheral neuropathies.

Adenoviridae↗
PubMed1998

Neural membrane protein 35 (NMP35): a novel member of a gene family which is highly expressed in the adult nervous system.

We have identified and isolated a cDNA that codes for the novel protein NMP35 (neural membrane protein 35) using RNA arbitrarily primed PCR (RAP-PCR) for differential display in the developing rat sciatic nerve. NMP35 is predominantly found in the adult nervous system where both transcripts and protein are strongly upregulated during postnatal development. In situ hybridization studies show that NMP35 mRNA is widely distributed in the brain and spinal cord with a neuronal expression pattern. Database comparisons reveal that NMP35 shares significant homologies with the rat glutamate-binding protein (GBP), the Drosophila NMDARA1, and two orphan C. elegans genes. Comparative analysis of NMP35 and GBP expression indicates that they are similarly regulated during development and display regionally overlapping cellular patterns. We conclude that NMP35 and GBP are members of a gene family which is likely to play a role in the development and the maintenance of the nervous system.

Age Factors↗
PubMed1996

Antisense globin RNA in mouse erythroid tissues: structure, origin, and possible function.

The aim of the experiments described in this paper was to test for the presence of antisense globin RNA in mouse erythroid tissues and, if found, to characterize these molecules. The present study made use of a multistep procedure in which a molecular tag is attached to cellular RNA by ligation with a defined ribooligonucleotide. The act of ligation preserves the termini of RNA molecules, which become the junctions between cellular RNAs and the ligated ribooligonucleotide. It also unambiguously preserves the identity of cellular RNA as a sense or antisense molecule through all subsequent manipulations. Using this approach, we identified and characterized antisense beta-globin RNA in erythroid spleen cells and reticulocytes from anemic mice. We show in this paper that the antisense globin RNA is fully complementary to spliced globin mRNA, indicative of the template/transcript relationship. It terminates at the 5' end with a uridylate stretch, reflecting the presence of poly(A) at the 3' end of the sense globin mRNA. With respect to the structure of their 3' termini, antisense globin RNA can be divided into three categories: full-size molecules corresponding precisely to globin mRNA, truncated molecules lacking predominantly 14 3'-terminal nucleotides, and extended antisense RNA containing 17 additional 3'-terminal nucleotides. The full-size antisense globin RNA contains two 14-nt-long complementary sequences within its 3'-terminal segment corresponding to the 5'-untranslated region of globin mRNA. This, together with the nature of the predominant truncation, suggests a mechanism by which antisense RNA might give rise to new sense-strand globin mRNA.

Anemia↗
PubMed1996

[Immuno-hemolytic transfusion reactions. III. Report of 61 cases].

Blood transfusion is mainly bound to immunological and infectious risks. The immunological risk originates from an incompatibility between the blood of the donor and that of the recipient; this risk remains insufficiently assessed. A multicentre study has been carried out by the French Blood Transfusion Society and the National Institute for Blood Transfusion. Sixty-one accidents due to an erythrocyte incompatibility were found: 26 cases with ABO incompatibility, and 35 cases with alloantibodies of other blood group systems. For the former category of accidents, the most frequent cause was due to a failure in the realization of the bedside ABO check. For the latter, the main problem was the achievement and the interpretation of antibody screening. The long term follow-up shows no chronic after-effects of immunological accidents. For each accident, errors have been identified and analysed. It was proven that they all originate from health care establishments.

ABO Blood-Group System↗
PubMed1996

Identification in situ and dynamics of bacteria on limnetic organic aggregates (lake snow).

Microbial assemblages on large organic aggregates (lake snow) of Lake Constance, Germany, were analyzed with rRNA-directed fluorescent oligonucleotide probes specific for the domain Bacteria and the alpha-, beta-, and gamma-subclasses of the class Proteobacteria. Lake snow aggregates were either collected in situ by SCUBA diving or in a sediment trap at 50 m or formed of natural lake water incubated in rolling cylinders under simulated in situ conditions. For the latter aggregates, the time course of the microbial colonization was also examined. The natural aggregates and those made in rolling cylinders were composed of the particulate organic material present in the lake and thus reflected the composition of the ambient plankton community. All types of lake snow aggregates examined were heavily colonized by microbial cells and harbored between 0.5 x 10(6) and > 2 x 10(6) cells aggregate -1. Between 55 and 100% of the microbial cells stained with 4', 6-diamidino-2-phenylindole (DAPI) could be visualized with the domain Bacteria-specific probe. In most samples, beta-subclass proteobacteria dominated the microbial community, constituting 27 to 42% of total cells as counted by DAPI staining, irrespective of the composition of the aggregates. During the time course experiments with the laboratory-made aggregates, the fraction of beta-subclass proteobacteria usually increased over time. Except for a few samples, alpha- and gamma-subclass proteobacteria were far less abundant than beta-subclass proteobacteria, constituting 11 to 25 and 9 to 33% of total cells, respectively. Therefore, we assume that a specific aggregate-adapted microbial community was established on the aggregates. Because the compositions of the microbial assemblages on natural and laboratory-made aggregates were similar, we conclude that aggregates made in rolling cylinders are good model system with which to examine the formation and microbial colonization of macroscopic organic aggregates.

Bacteria↗