Biomedical subjects

Michel Rossignol

Publications and source records attributed to Michel Rossignol.

At least 37 records · Page 2Linked to original sources

PubMed2005

Cell wall proteins in apoplastic fluids of Arabidopsis thaliana rosettes: identification by mass spectrometry and bioinformatics.

Weakly bound cell wall proteins of Arabidopsis thaliana were identified using a proteomic and bioinformatic approach. An efficient protocol of extraction based on vacuum-infiltration of the tissues was developed. Several salts and a chelating agent were compared for their ability to extract cell wall proteins without releasing cytoplasmic contaminants. Of the 93 proteins that were identified, a large proportion (60%) was released by calcium chloride. From bioinformatics analysis, it may be predicted that most of them (87 out of 93) had a signal peptide, whereas only six originated from the cytoplasm. Among the putative apoplastic proteins, a high proportion (67 out of 87) had a basic pI. Numerous glycoside hydrolases and proteins with interacting domains were identified, in agreement with the expected role of the extracellular matrix in polysaccharide metabolism and recognition phenomena. Ten proteinases were also found as well as six proteins with unknown functions. Comparison of the cell wall proteome of rosettes with the previously published cell wall proteome of cell suspension cultures showed a high level of cell specificity, especially for the different members of several large multigenic families.

Arabidopsis↗

PubMed2005

MS characterization of multiple forms of alpha-amylase in human saliva.

Alpha-amylase is a major and well-characterized component of human saliva. Recent proteomic studies suggested that this protein could be observed in more than twenty spots on 2-D gels of salivary proteins. The aim of this work was to investigate this unexpected redundancy. 2-D gel electrophoresis was combined with systematic MALDI-TOF MS analysis. More than 140 protein spots identifying the alpha-amylase were shown to constitute a stable but very complex pattern. Careful analysis of mass spectra and simultaneous hierarchical clustering of the observed peptides and of the electrophoretic features of spots allowed one to define three major groups. A main class grouping 90 spots was shown to correspond to full length alpha-amylases that can be assumed to include isoforms and post-translationally modified forms, a subset of this class being demonstrated to be N-glycosylated. A second group included short alpha-amylases that are differently truncated in a non-random manner, very likely in the oral cavity. The last class grouped alpha-amylase forms showing both the N- and C-terminal sequences of the enzyme but displaying a molecular weight that was up to 50% lower than that of the native protein. It is speculated that the last group of alpha-amylase spots could correspond to proteins submitted to internal deletions prior to the secretion.

Amino Acid Sequence↗

PubMed2005

Impact of osteoarthritis: results of a nationwide survey of 10,000 patients consulting for OA.

UNLABELLED: The clinical burden of osteoarthritis (OA) is difficult to assess because of the substantial variability between patients. OBJECTIVE: Evaluate the human consequences of OA in patients. METHODS: In 2000, a nationwide survey was conducted among a sample of more than 5000 physicians (90.3% general practitioners and 9.7% rheumatologists), representative of French physicians. Each recruited the first two patients consulting for hip, knee, or hand OA after the survey began. The functional limitation rates were compared with those for age- and sex-matched controls obtained from the 1999 population-based national survey on disability (HID survey). RESULTS: Clinical and demographic information was obtained for 10,412 OA patients (mean-age 66.2 years, sex ratio F:M 1.96). The OA diagnosis was based on both clinical and radiographic findings for 84.5%. More than 80% of all patients reported limitations in their activities of daily living, either for basic tasks, leisure activities, or work. OA patients were substantially more limited than controls: the standardised limitation rate ratios (SLRR) were 6.0 (95% confidence interval: 5.9:6.1) for mobility outside the home, 2.1 (2.0:2.1) for house cleaning, 1.6 (1.5:1.8) for dressing oneself, and 1.6 (1.5:1.8) for sports. Of the 17.6% of OA patients and 17.5% of the controls still working, 64.4% and 14.3%, respectively, were limited in their job duties, for a SLRR of 4.5 (4.3:4.7). CONCLUSION: This study shows that OA-related disability has a significant impact on the retired as well as on those still involved in the labour market.

Adult↗

PubMed2005

A randomized, double-blind, placebo controlled triphosphate in study of oral adenosine subacute low back pain.

OBJECTIVE: To assess the efficacy and safety of oral adenosine triphosphate (ATP) in subacute low back pain. METHODS: This was a randomized, double-blind, parallel group, placebo controlled clinical trial. The patients were given either ATP 90 mg once daily (n=81) or placebo (n=80) for one month. The patients were assessed 3 times during the study period, at days 0, 7, and 30. The primary outcome measure was the Roland-Morris Disability Questionnaire (RDQ) at day 30. Secondary measures of efficacy included visual analog scale (VAS) pain, overall assessments of efficacy by both patient and investigator, and number of dextropropoxyphene and acetaminophen combination tablets used as rescue analgesic. RESULTS: Regarding the RDQ, the mean values dropped from 10.3 +/-2.8 at baseline to 7.5 +/-3.8 (day 7) and 5.2 +/-5.2 (day 30) in the ATP group, and from 11.0 +/- 3.5 to 9.1 +/- 4.2 (day 7) and 6.1 +/- 4.3 (day 30) in the placebo group. The difference between the 2 groups was statistically significant at day 7 (p= 0.02) but not at day 30 (p=0.2). In other words, the mean changes from baseline were 2.8 +/- 3.1 and 2.0 +/- 2.6 at day 7 (p=0.06), and 5.1 +/- 3.9 and 5.0 +/- 4.2 at day 30 (p=0.78) in the ATP group and the placebo group, respectively. There were no statistically significant differences in the VAS pain and overall assessments of efficacy between groups at any time point during the study. Conversely, there was a significant difference in the use of the rescue analgesic between groups, in favor of ATP (p=0.04). Oral ATP was well tolerated. CONCLUSION: Oral ATP might have an early acting effect in subacute low back pain.

Adenosine Triphosphate↗

PubMed2005

Comorbidity and age are both independent predictors of length of hospitalization in trauma patients.

BACKGROUND: Length of hospitalization is a good indicator of resource utilization. Older patients are increasingly suffering trauma, and comorbid medical conditions are also increasing. Our objective was to determine the separate and combined effect of these 2 factors on length of hospital stay for trauma patients in a tertiary trauma centre. METHODS: All 994 consecutive trauma patients surviving to hospital discharge between Apr. 1, 2000, and Mar. 31, 2001, were identified. Patient characteristics, injury severity and length of hospitalization were obtained from the hospital trauma registry. Each medical record was then reviewed for completeness of information and assessment of comorbid conditions. A multivariate linear regression model was developed to predict logarithmic length of stay from age and presence of a cormorbid condition while adjusting for the Injury Severity Score (ISS). RESULTS: The mean age of the patients was 49.7 (range from 14-100) years and median ISS was 9 (range from 1-50). At least 1 comorbid condition was present in 321 (32%) patients. Mean length of hospital stay was 15.3 days. The proportion of patients with a comorbid condition increased steadily with age, from 8.7% before the age of 55 years to 92% at 85 or more years of age (p < 0.001). According to the multivariate model, the presence of comorbidity, age and ISS were all independent predictors of hospital stay (p < 0.001). When applied to patients with the mean ISS value of 9, the model showed an increase in length of hospitalization for patients with a comorbid condition over those without; (3.6 v. 13.1 d for patients < 55 and > or = 85 yr respectively). Length of hospital stay increased particularly with neurologic and pulmonary problems. CONCLUSIONS: Comorbidity and age were both independently significant predictors of length of hospitalization over and beyond that which is expected based on the severity of the injuries. With an aging population, this phenomenon should severely affect resource utilization in trauma centres in the near future. Researchers should take account of both age and comorbidity in order to compare trauma populations.

Adolescent↗

PubMed2005

Physical therapists' use of interventions with high evidence of effectiveness in the management of a hypothetical typical patient with acute low back pain.

BACKGROUND AND PURPOSE: Evidence-based practice aims to improve patient care and service delivery, particularly in the management of individuals with low back pain (LBP), the largest client group seen by outpatient physical therapists. The purpose of this study was to determine the prevalence of use of interventions with evidence of effectiveness in the management of acute nonspecific LBP by physical therapists. SUBJECTS: A multicenter cross-sectional study was conducted on 100 physical therapists working with patients with LBP. METHODS: Using a telephone-administered interview, therapists described their current and desired treatment practices for a typical case of LBP. Each intervention reported was coded according to its evidence of effectiveness (strong, moderate, limited, or none). Information on clinician, workplace, and client characteristics also was obtained. RESULTS: The prevalence of use of interventions with strong or moderate evidence of effectiveness was 68%. However, 90% to 96% of therapists also used interventions for which research evidence was limited or absent. Users of interventions with high evidence of effectiveness, as compared with nonusers, had graduated more recently and had taken a higher number of postgraduate clinical courses. DISCUSSION AND CONCLUSION: Although most therapists use interventions with high evidence of effectiveness, much of their patient time is spent on interventions that are not well reported in the literature. The results indicate the need for improvement in the quality of clinical research as well as its dissemination and implementation in a way that is appealing to therapists, such as through practice-related courses.

Acute Disease↗

PubMed2005

Management of work-related low back pain: a population-based survey of physical therapists.

BACKGROUND AND PURPOSE: Physical therapy often is used in the management of work-related low back pain (LBP). Little information, however, is known about the types of interventions used by physical therapists in the management of this condition. The objective of this study was to describe the interventions used by physical therapists in the treatment of workers with acute or subacute LBP, with or without radiating pain below the knee. SUBJECTS: Clinical management questionnaires for workers without and with radiating pain were returned by 190 and 139 physical therapists, respectively. METHODS: For each treatment session, therapists recorded treatment objectives, interventions, and education provided to 2 workers with LBP, 1 with radiating pain and 1 without radiating pain. RESULTS: The majority of physical therapists used stretching and strengthening exercises, spinal mobilization, soft tissue mobilization and massage, manual traction, posture correction, interferential current, ultrasound, heat, and functional activities education. With radiating pain, the majority of the therapists also used cold and the McKenzie approach. Treatment objectives pursued by the majority of the therapists were decrease of pain, increase of range of motion, increase of muscle strength (force-generating capacity of muscle), decrease of muscle tension, and worker education. DISCUSSION AND CONCLUSION: Physical therapists use an array of interventions with workers with LBP. The effectiveness of most interventions reported has not been well studied.

Absenteeism↗

PubMed2004

Deciphering the plant phosphoproteome: tools and strategies for a challenging task.

Protein phosphorylation constitutes a major type of post-translational modification that mobilizes a high number of genes, especially in plants, is involved in many crucial cell functions and largely participates to the complexity of the proteomes. For several biological and technical reasons, the characterization of phosphorylation sites requires complex procedures. In this review, the different approaches presently available to select phosphoproteins and phosphopeptides are described. A special emphasis is then given to the numerous strategies that have emerged for the analysis of phosphorylation sites by various techniques of mass spectrometry. Finally, the few attempts proposed for the quantification of phosphorylation events are presented. In another part, the results of the efforts made in the plant area to analyze the phosphoproteome are compared to those in other biological systems. These overviews are put together to delineate, according to the objectives pursued, the different strategies possible and the corresponding challenges.

Phosphoproteins↗

PubMed2004

Grape berry biochemistry revisited upon proteomic analysis of the mesocarp.

Major soluble proteins of grapevine ripe berries were extracted from six different cultivars including non vinifera, with trichloroacetic acid acetone and resolved in two-dimensional electrophoresis (2-DE) gels. About three hundred spots were detected on the 2-DE map after colloidal blue staining. From 2-DE map of cv. Gamay mesocarp, 67 proteins were identified (p > 0.95) using matrix-assisted laser desorption/ionization-mass spectrometry analysis. About 34%, 19%, and 13% of identified proteins play, respectively, a role in energy metabolism, defense, and stress response and primary metabolism. 2-DE analysis revealed considerable accumulation of dehydrin, invertase, and a putative transcription factor in the ripe fruit, in addition to pathogenesis-related proteins such as chitinase and thaumatin-like proteins previously documented as prevalent proteins in ripe berries. Actual translation of redundant transcripts of unclear function such as Grip31, Grip32, and Grip61 recently cloned in ripe grape berries was confirmed. The relative abundance of UDP-glucose pyrophosphorylase and vacuolar invertase strongly supported a key role of the apoplastic pathway of sugar loading during ripening. Comparative analysis shows that differences between cultivars were low, but different isoforms of alcohol dehydrogenase and of a transcription factor of hexose transporter were obvious in the six cultivars. Peptide mass fingerprinting suggests that the Adh isoforms would be Adh2/Adh6 or Adh2/Adh7 dimers and unambiguously shows that considerable deletion/insertion inside Adh7 are not cloning artifacts.

Electrophoresis, Gel, Two-Dimensional↗

PubMed2004

Plant proteome analysis.

Proteome analysis is becoming a powerful tool in the functional characterization of plants. Due to the availability of vast nucleotide sequence information and based on the progress achieved in sensitive and rapid protein identification by mass spectrometry, proteome approaches open up new perspectives to analyze the complex functions of model plants and crop species at different levels. In this review, an overview is given on proteome studies performed to analyze whole plants or specific tissues with particular emphasis on important physiological processes such as germination. The chapter on subcellular proteome analysis of plants focuses on the progress achieved for plastids and mitochondria but also mentions the difficulties associated with membrane-bound proteins of these organelles. Separate chapters are dedicated to the challenging analysis of woody plants and to the use of proteome approaches to investigate the interaction of plants with pathogens or with symbiotic organisms. Limitations of current techniques and recent conceptual and technological perspectives for plant proteomics are briefly discussed in the final chapter.

Electrophoresis, Gel, Two-Dimensional↗

PubMed2004

Large-scale characterization of integral proteins from Arabidopsis vacuolar membrane by two-dimensional liquid chromatography.

We developed a method to characterize different classes of membrane proteins within a single experiment and using simple matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) analysis. After membrane solubilization with the nondenaturing detergent n-dodecyl-beta-D-maltoside, proteins were separated successively by gel filtration and ion-exchange chromatography and finally by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This procedure allowed to characterize 70 proteins from a membrane fraction enriched in plant vacuolar membrane (Arabidopsis), including integral proteins like the V0 complex of the H(+)-ATPase, the H(+)-pyrophosphatase or the glutathione S-conjugate ATPase AtMRP1, and peripheral proteins like the subunits of the catalytic V1 complex of the H(+)-ATPase. Approximately 60% of identified proteins were predicted to possess at least two trans-membrane domains. Furthermore, proteins, with molecular masses ranging between 20 and 200 kDa were distributed into two populations with maximum frequencies at pI 5.3 and 8.9. Finally, this procedure appeared to allow the identification of proteins known to be minor in whole-cell extracts like signaling or vesicular trafficking proteins. Almost 50% of the proteins identified were functionally unknown whereas the others confirmed that the plant vacuole is a multipurpose compartment.

Arabidopsis↗

PubMed2004

Comparison of the proteome of Methylobacterium extorquens AM1 grown under methylotrophic and nonmethylotrophic conditions.

Methylobacterium extorquens AM1 is a facultative methylotrophic bacterium that is capable of growing in the presence of methanol as the sole carbon and energy source, but is also able to grow on a limited number of C(2), C(3), and C(4) compounds, for example succinate. This study provides a proteomic view of the cellular adaptation of M. extorquens AM1 to growth on methanol and succinate, respectively. Cytosolic proteins were separated by two-dimensional gel electrophoresis employing overlapping pH ranges and visualized by silver nitrate or fluorescence staining. A proteomic reference map containing 229 different proteins identified by peptide mass fingerprinting of tryptic fragments was established. Comparative proteome profiling of methanol- and succinate-grown cells led to the identification of 68 proteins that are induced under methylotrophic growth conditions in comparison to growth on succinate. This group includes most proteins known to be directly involved in methanol oxidation to CO(2) and in assimilation of one carbon units by the serine cycle as well as 18 proteins without any assigned function and two proteins with a predicted regulatory function. Furthermore, the proteome analysis revealed putative isoenzymes for formaldehyde-activating enzyme Fae, malyl-CoA lyase, malate-dehydrogenase, and fumarase, that need to be characterized functionally in future studies.

Bacterial Proteins↗

PubMed2004

Proteomic investigation of natural variation between Arabidopsis ecotypes.

Two-dimensional (2-D) gel electrophoresis and peptide mass fingerprinting were used to investigate the natural variation in the proteome among 8 Arabidopsis thaliana ecotypes, of which 3 were previously shown to display atypical responses to environmental stress. Comparison of 2-D maps demonstrated that only one-quarter of spots was shared by all accessions. On the other hand, only 15% of the 25 majors spots accounting for half the total protein amount could be classified as major spots in all ecotypes. Identification of these major spots demonstrated large differences between the major functions detected. Accordingly, the proteomes appeared to reveal important variations in terms of function between ecotypes. Hierarchical clustering of proteomes according to either the amount of all anonymous spots, that of the 25 major spots or the functions of these major spots identified the same classes of ecotypes, and grouped the three atypical ecotypes. It is proposed that proteome comparison has the capacity to evidence differences in the physiological status of ecotypes. Results are discussed with respect to the possibility to infer such differences from limited comparisons of major proteins. It is concluded that classical proteomics could constitute a powerful tool to mine the biodiversity between ecotypes of a single plant species.

Arabidopsis↗

PubMed2004

Proteomic capacity of recent fluorescent dyes for protein staining.

Staining of two-dimensional gel constitutes a crucial step in comparative proteome analysis with respect to both the number of proteins analysed, the accuracy of spot quantification and reproducibility. In this work, we compared the efficiency of recent fluorophores to stain Arabidopsis total protein extract: Sypro Ruby (SR), Deep Purple (DP) and 5-hexadecanoylamino-fluorescein (C16-F). In addition, classical visible dyes, colloidal Coomassie blue (CCB) and silver nitrate (SN), were also included. High quality images were obtained for the three fluorescent dyes, DP giving the cleaner background, whereas spikes were observed with SR and a rough background with C16-F. On the other hand, saturation occurred for abundant spots with SR and DP. For a same protein load the number of detected spots ranged between 250 for CCB and 800 for SR in the sequence SR > DP approximately SN > C16-F > CCB. These differences were shown to rely mainly on the sensitivity between dyes leading to the detection of additional spots belonging to classes of lower abundance. Analysis of the distribution of variation coefficients for spots from replicates showed differences in the staining reproducibility between dyes that ranged in the order SR > C16-F > DP > SN > CCB. The implications of these results for the selection of a convenient stain are discussed according to specific objectives as well as practical aspects.

Arabidopsis↗

PubMed2004

Characterization of proteins secreted during maize microspore culture: arabinogalactan proteins (AGPs) stimulate embryo development.

To study molecules secreted from cultured plant cells that promote development, maize microspores were transferred into culture and the conditioned media were collected over time and analysed. Electrophoresis indicated that both non-glycosylated and glycosylated proteins including arabinogalactan proteins (AGPs) appeared in the medium and their concentration increased during the time of culture. The development of embryos was correlated with the presence of specific extracellular proteins, using an experimental system based on a tunicamycin inhibition test. In addition, a precise protein analysis was conducted using MALDI-TOF and ESI-MS-MS techniques. These approaches have allowed the identification of 5 other types of proteins: a cell wall invertase, two thaumatin isoforms, one 1-3 beta-glucanase and two chitinase isoforms. Altogether these experiments and results open ways for research aimed at understanding which molecules stimulate embryo formation. Moreover, AGPs may be used to stimulate the development of microspores (pollen embryogenesis) prepared from non-responsive genotypes.

Culture Media, Conditioned↗

PubMed2004

Improving the TRISS methodology by restructuring age categories and adding comorbidities.

BACKGROUND: The Trauma and Injury Severity Score (TRISS) methodology was developed to predict the probability of survival after trauma. Despite many criticisms, this methodology remains in common use. The purpose of this study was to show that improving the stratification for age and adding an adjustment for comorbidity significantly increases the predictive accuracy of the TRISS model. METHODS: The trauma registry and the hospital administrative database of a regional trauma center were used to identify all blunt trauma patients older than 14 years of age admitted with International Classification of Diseases, Ninth Revision codes 800 to 959 from April 1993 to March 2001. Each individual medical record was then reviewed to ascertain the Revised Trauma Score, the Injury Severity Score, the age of the patients, and the presence of eight comorbidities. The outcome variable was the status at discharge: alive or dead. The study population was divided into two subsamples of equal size using a random sampling method. Logistic regression was used to develop models on the first subsample; a second subsample was used for cross-validation of the models. The original TRISS and three TRISS-derived models were created using different categorizations of Revised Trauma Score, Injury Severity Score, and age. A new model labeled TRISSCOM was created that included an additional term for the presence of comorbidity. RESULTS: There were 5,672 blunt trauma patients, 2,836 in each group. For original TRISS, the Hosmer-Lemeshow statistic (HL) was 179.1 and the area under the receiver operating characteristic (AUROC) curve was 0.873. Sensitivity and specificity were 99.0% and 27.8%, respectively. For the best modified TRISS model, the HL statistic was 20.35, the AUROC curve was 0.902, the sensitivity was 99.0%, and the specificity was 27.8%. For TRISSCOM, the HL statistic was 14.95 and the AUROC curve was 0.918. Sensitivity and specificity were 99.0% and 29.7%, respectively. The difference between the two models almost reached statistical significance (p = 0.086). When TRISSCOM was applied to the cross-validation group, the HL statistic was 10.48 and the AUROC curve was 0.914. The sensitivity was 98.6% and the specificity was 34.9%. CONCLUSION: TRISSCOM can predict survival more accurately than models that do not include comorbidity. A better categorization of age and the inclusion of comorbid conditions in the logistic model significantly improves the predictive performance of TRISS.

Adolescent↗

PubMed2003

Application of molecular beam deflection time-of-flight mass spectrometry to peptide analysis.

The application of molecular beam deflection time-of-flight mass spectrometry (MBD-TOFMS) to peptide identification is described. The technique permits a simultaneous measurement of molecular mass and electric dipole susceptibility. The mass and susceptibility are not strongly correlated, and the results can be presented as a two-dimensional map. The susceptibility provides a useful way to disperse isobaric and isomeric peptides, and at least for small peptides, the susceptibility is significantly different for different amino acid sequences. Results for peptides in the mass range 1000-2300 Da show that the mass and susceptibility lead to a higher identification score than mass spectra alone.

Algorithms↗

PubMed2003

Comparison between tests of fatigue and force for trunk flexion.

STUDY DESIGN: A quasi-experimental study was conducted. OBJECTIVE: To compare intraindividual differences between trunk flexion isometric force, fatigue during isometric contraction (isometric fatigue), and fatigue during sit-ups (dynamic fatigue). SUMMARY OF BACKGROUND DATA: Trunk flexion force and trunk flexion fatigue commonly are used to assess trunk flexion fitness. The use of one test is appropriate only if the tests are highly correlated. METHODS: This study measured force and either isometric fatigue (time to task failure, n = 79) or dynamic fatigue (number of sit-ups in 2 minutes, n = 73) in self-selected, healthy secondary school (I-III) subjects. In 15 subjects, both isometric and dynamic fatigue were measured. RESULTS: After control was used for upper body mass, the R2(adj) was 0.34 between isometric force and isometric fatigue, 0.31 between isometric force and dynamic fatigue was, and 0.27 between dynamic fatigue and isometric fatigue. Including gender in the model did not affect the results. CONCLUSIONS: The lack of a high correlation between trunk flexion isometric fatigue, dynamic fatigue, and isometric force suggests that health care professionals should be careful to select the test that answers their particular needs or question.

Abdomen↗