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Biomedical subjects

A Blanchard

Publications and source records attributed to A Blanchard.

At least 19 recordsLinked to original sources
PubMed2006

[Transition in health care from youth to adulthood for disabled people].

Most children born with a chronic health condition or disability are expected to live more than 20 years. Health care is provided for these children in paediatric units until they are 18 years old, and the transition to the adult health care system is difficult because of poor collaboration between specialists and families who sometimes wonder if the adult specialist will be competent, although young disabled people need specialised follow-up. This report discusses U.S. and English models in the transition in health care. Coordination between paediatricians and adult services is necessary. The neuromuscular disorders clinic is cited as an example.

Adolescent↗
PubMed2005

Small angle neutron scattering observation of chain retraction after a large step deformation.

The process of retraction in entangled linear chains after a fast nonlinear stretch was detected from time-resolved but quenched small angle neutron scattering (SANS) experiments on long, well-entangled polyisoprene chains. The statically obtained SANS data cover the relevant time regime for retraction, and they provide a direct, microscopic verification of this nonlinear process as predicted by the tube model. Clear, quantitative agreement is found with recent theories of contour length fluctuations and convective constraint release, using parameters obtained mainly from linear rheology. The theory captures the full range of scattering vectors once the crossover to fluctuations on length scales below the tube diameter is accounted for.

Journal Article↗
PubMed2005

[Leather corset for the treatment of camptocormia: 31 cases].

INTRODUCTION: Camptocormia is an acquired postural disease leading to wide-ranging emerging rachidian kyphosis. Kyphosis can be observed when the patient stands up, walks or sits. The functional impact can be significant. When the etiology is better known, personalized treatments are often deceitful. Physical therapy and orthesis may be proposed. Classical antikyphotic orthesis for the trunk are usually not well tolerated and are quickly abandoned. We proposed the use of traditional leather orthesis for such cases. MATERIALS AND METHOD: This retrospective study undertaken between April 2001 and April 2003 included 31 patients with camptocormia for whom orthesis was indicated. Eight patients benefited from use of a classical lumbar belt. All assessed the ortheses as not satisfactory. In 27 patients, leather orthesis was prescribed, and 20 used it, 19 of whom answered a questionnaire assessing functional benefits as follows: the patient is well or very well straightened, suffers less from trunk pain, suffers less or no longer when standing up without assistance during a long period, has less or no difficulty to walk, feels less or no longer tired because of the effort to stay straight without the orthesis, does not resent the alteration of social life because of the orthesis, and assesses active life as satisfactory. RESULTS: The average time to wear the othesis was 33 months. Sixty-eight percent of patients wore it at least 9 hours a day; 84% were able to put it on by themselves. The respiratory and cutaneous consequences were judged good and digestive and urinary tolerance adequate. With the orthesis, 74% of the patients responded positively to 5 of the 7 functional areas assessed. Why patients do not wear ortheses is often explained by the failure to obtain a satisfactory straight position and/or an ankle flexion, associated significant pathology, lack of motivation and difficulty in putting the orthesis on alone.

Aged↗
PubMed2004

Contagious bovine pleuropneumonia vaccines and control strategies: recent data.

Contagious bovine pleuropneumonia is one of the most threatening transboundary cattle disease in Africa. However, with the exception of Botswana, very few African countries were able to implement eradication strategies for this disease, after it had recently re-infected a number of countries. Previous experimental studies have shown that emergency vaccination campaigns, based on a single injection, were not inducing a sufficient protection level to prevent further spread of the disease. In addition, post-vaccinal reactions were sometimes reported in the field when using vaccine strain T1/44, leading cattle owners to refuse the vaccination. On the contrary, antibiotics are used quite often in the field but there are insufficient data to assess their efficacy properly. Therefore experimental studies were implemented: (i) to check if higher dosages of the vaccine would be able to induce higher protection rates and (ii) to elucidate the origin of the post-vaccinal reactions observed with T1/44 and (iii) to gain preliminary results on the efficacy of long-acting tetracycline. The first experiment included the use of three doses of vaccine strains T1/44 and T1sr: 10(7), 10(8) and 10(9) mycoplasmas per dose. T1/44 seemed to induce a higher protection (70%) than T1sr (60%). However, there was no observable dose effect for these vaccine strains. The second experiment was performed by injecting various MmmSC strains subcutaneously into susceptible cattle. One of these strains was an isolate obtained from a "Willems" reaction following a vaccination with T1/44. This isolate, called T1B, induced typical invading oedema at the injection site in a similar way to the pathogenic strain, whereas the original T1/44 vaccine strain did not. These findings indicate that the strain has reverted to virulence. Finally the antibiotic trials showed that long-acting tetracycline was able to reduce the losses due to the disease but could not prevent the persistence of viable MmmSC in treated animals. The consequences of these findings are discussed. They reinforce the need for additional research on new vaccines able to elicit longer lasting protection. However, once continuing additional field research is obtained, it should allow better defined strategies to be put in place. Meanwhile, immediate action should be taken to prevent the further spread of CBPP in the Southern part of Africa.

Africa↗
PubMed2002

Identification of the origin of replication of the Mycoplasma pulmonis chromosome and its use in oriC replicative plasmids.

Mycoplasma pulmonis is a natural rodent pathogen, considered a privileged model for studying respiratory mycoplasmosis. The complete genome of this bacterium, which belongs to the class Mollicutes, has recently been sequenced, but studying the role of specific genes requires improved genetic tools. In silico comparative analysis of sequenced mollicute genomes indicated the lack of conservation of gene order in the region containing the predicted origin of replication (oriC) and the existence, in most of the mollicute genomes examined, of putative DnaA boxes lying upstream and downstream from the dnaA gene. The predicted M. pulmonis oriC region was shown to be functional after cloning it into an artificial plasmid and after transformation of the mycoplasma, which was obtained with a frequency of 3 x 10(-6) transformants/CFU/ micro g of plasmid DNA. However, after a few in vitro passages, this plasmid integrated into the chromosomal oriC region. Reduction of this oriC region by subcloning experiments to the region either upstream or downstream from dnaA resulted in plasmids that failed to replicate in M. pulmonis, except when these two intergenic regions were cloned with the tetM determinant as a spacer in between them. An internal fragment of the M. pulmonis hemolysin A gene (hlyA) was cloned into this oriC plasmid, and the resulting construct was used to transform M. pulmonis. Targeted integration of this genetic element into the chromosomal hlyA by a single crossing over, which results in the disruption of the gene, could be documented. These mycoplasmal oriC plasmids may therefore become valuable tools for investigating the roles of specific genes, including those potentially implicated in pathogenesis.

Bacterial Proteins↗
PubMed2001

The complete genome sequence of the murine respiratory pathogen Mycoplasma pulmonis.

Mycoplasma pulmonis is a wall-less eubacterium belonging to the Mollicutes (trivial name, mycoplasmas) and responsible for murine respiratory diseases. The genome of strain UAB CTIP is composed of a single circular 963 879 bp chromosome with a G + C content of 26.6 mol%, i.e. the lowest reported among bacteria, Ureaplasma urealyticum apart. This genome contains 782 putative coding sequences (CDSs) covering 91.4% of its length and a function could be assigned to 486 CDSs whilst 92 matched the gene sequences of hypothetical proteins, leaving 204 CDSs without significant database match. The genome contains a single set of rRNA genes and only 29 tRNAs genes. The replication origin oriC was localized by sequence analysis and by using the G + C skew method. Sequence polymorphisms within stretches of repeated nucleotides generate phase-variable protein antigens whilst a recombinase gene is likely to catalyse the site-specific DNA inversions in major M.pulmonis surface antigens. Furthermore, a hemolysin, secreted nucleases and a glyco-protease are predicted virulence factors. Surprisingly, several of the genes previously reported to be essential for a self-replicating minimal cell are missing in the M.pulmonis genome although this one is larger than the other mycoplasma genomes fully sequenced until now.

Animals↗
PubMed2001

Paracellin-1 is critical for magnesium and calcium reabsorption in the human thick ascending limb of Henle.

BACKGROUND: A new protein, named paracellin 1 (PCLN-1), expressed in human thick ascending limb (TAL) tight junctions, possibly plays a critical role in the control of magnesium and calcium reabsorption, since mutations of PCLN-1 are present in the hypomagnesemia hypercalciuria syndrome (HHS). However, no functional experiments have demonstrated that TAL magnesium and calcium reabsorption were actually impaired in patients with HHS. METHODS: Genetic studies were performed in the kindred of two unrelated patients with HHS. Renal magnesium and calcium reabsorption in TAL were analyzed in one homozygous affected patient of each family, one patient with extrarenal hypomagnesemia (ERH), and two control subjects (CSs). RESULTS: We found two yet undescribed mutations of PCLN-1 (Gly 162 Val, Ala 139 Val). In patients with HHS, renal magnesium and calcium reabsorptions were impaired as expected; NaCl renal conservation during NaCl deprivation and NaCl tubular reabsorption in diluting segment were intact. Furosemide infusion in CS markedly increased NaCl, Mg, and Ca urinary excretion rates. In HHS patients, furosemide similarly increased NaCl excretion, but failed to increase Mg and Ca excretion. Acute MgCl(2) infusion in CS and ERH patient provoked a dramatic increase in urinary calcium excretion without change in NaCl excretion. When combined with MgCl(2) infusion, furosemide infusion remained able to induce normal natriuretic response, but was unable to increase urinary magnesium and calcium excretion further. In HHS patients, calciuric response to MgCl(2) infusion was blunted. CONCLUSION: This study is the first to our knowledge to demonstrate that homozygous mutations of PCLN-1 result in a selective defect in paracellular Mg and Ca reabsorption in the TAL, with intact NaCl reabsorption ability at this site. In addition, the study supports a selective physiological effect of basolateral Mg(2+) and Ca(2+) concentration on TAL divalent cation paracellular permeability, that is, PCLN-1 activity.

Adolescent↗
PubMed2001

Phase variation among major surface antigens of Mycoplasma penetrans.

The pathogenicity and prevalence of Mycoplasma penetrans, a Mycoplasma species recently isolated from humans, are still debated. A major P35 antigen, which is used as target epitope in serological assays, was shown to be a phase-variable lipid-associated membrane protein (LAMP). In this study, we performed a comparative analysis of the LAMP patterns from five M. penetrans clinical isolates and from the type strain. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles and immunoblots with sera serially collected from an M. penetrans-infected patient indicated that these strains expressed different LAMP repertoires. Furthermore, the intraclonal variation in the expression of LAMPs (P34A, P34B, P35, and P38) was monitored by immunoblot analysis with three specific monoclonal antibodies (MAbs) developed in this study and MAb 7 to P35. The phase variation of these LAMPs occurs in an independent manner, with frequencies of variation ranging from 10(-2) to 10(-4) per cell per generation. Consistent with their amphipathic nature, the P34B and P38 antigens were found exposed at the cell surface. The DNA sequence encoding the P38 antigen was defined and found to be related to those of the P35 gene and other putative LAMP-encoding genes, suggesting that these variable antigens are encoded by a family of related genes. Finally, the serum samples from an M. penetrans-infected patient contained antibodies that reacted with a P36 antigen expressed in different M. penetrans strains but not in the isolate recovered from this patient. This result suggested that in vivo phase variation of P36 occurred, which would support a role for these LAMP variations in avoiding the host's immune vigilance.

Amino Acid Sequence↗
PubMed2000

Detection of Ureaplasma diversum in cattle using a newly developed PCR-based detection assay.

Ureaplasma diversum has been associated with different clinical manifestations including bovine vulvitis, endometritis, salpingitis, spontaneous abortion and infertility. Because the isolation of this ureaplasma from clinical samples is difficult, there is a need for improved detection methods. We developed a PCR assay based on amplification of a region of the gene encoding 16S rRNA. The specificity of the amplification was verified by sequence analysis. Female bovine vaginal swabs (n=168) were collected and the presence of U. diversum evaluated by both culture methods and by the PCR assay. Culture was positive for 60 samples (35.7%), and PCR-specific amplification was obtained for 89 samples (52.9%). These results indicated a high prevalence of U. diversum in the selected animals and the higher sensitivity of this PCR assay as compared to culture.

Animals↗
PubMed2000

The effect of drought stress on inbreeding depression in four populations of the Mediterranean outcrossing plant Crepis sancta (Asteraceae).

The effect of physiological stress on the magnitude of inbreeding depression in plants has been the subject of few studies and is currently controversial because of contradictory results. We measured the inbreeding depression at three drought stress levels, precisely defined by a preliminary physiological experiment. We also tested the hypothesis that more highly self-compatible populations exhibit reduced inbreeding depression due to purging of deleterious mutations. The study was conducted on two populations of the annual and allogamous plant Crepis sancta collected from the French Mediterranean region and two other populations from marginal areas with various self-incompatibility levels. Drought stress did not increase inbreeding depression in terms of plant mortality but significantly increased the inbreeding depression for the date of first flowering, number of heads per plant and relative growth rate. The most self-fertile marginal population showed an absence of inbreeding depression in most of the measured traits indicating that purging could have taken place in this population. The three others populations showed relatively low and similar estimates of inbreeding depression (delta approximately 0.35). The relatively low values obtained compared to the results found in allogamous plants suggests that the absence of competition for C. sancta in our experiment probably underestimated the effects of inbreeding in natural populations where competition occurs.

Analysis of Variance↗
PubMed2000

Prognostic value of postoperative carcinoembryonic antigen concentration and extent of invasion of resection margins after hepatic resection for colorectal metastases.

OBJECTIVE: To evaluate the prognostic value of postoperative concentration of carcinoembryonic antigen (CEA) and extent of surgical margins after resection of liver metastases from colorectal cancer. DESIGN: Retrospective study. SETTING: Teaching hospital, Switzerland. SUBJECTS: 49 patients with hepatic metastases after primary colorectal cancer. INTERVENTIONS: Resection of hepatic metastases MAIN OUTCOME MEASURES: Assessment of prognostic value of variables by univariate and multivariate analysis. RESULTS: Median survival was 24 months (range 5-86 months). Resection margins were clear (> 1-cm) in 10, close (< 1-cm) in 25 and invaded in 9 patients. On univariate analysis, a postoperative concentration of CEA of <4ng/ml was correlated with prolonged survival (p < 0.001), but the width of the resection margin was not of prognostic importance. There was no correlation between width of resection margins and postoperative concentration of CEA (p = 0.5). On multivariate analysis, postoperative concentrations of CEA of 4 ng/ml or more were associated with increased risk of death (relative risk 7.3; 95% confidence interval (CI) 2.8-18.7, p < 0.001). CONCLUSION: Postoperative CEA offers better prognostic discrimination than the width of resection margins after resection of liver metastases from colorectal tumours. Some patients with invaded resection margins did survive for 3 years, but no patient did whose CEA concentration was 4 ng/ml or more. The definition of a potentially curative hepatic resection should include a postoperative CEA concentration of <4 ng/ml (within the reference range).

Carcinoembryonic Antigen↗
PubMed2000

Higher prevalence of urogenital mycoplasmas in human immunodeficiency virus-positive patients as compared to patients with other sexually transmitted diseases.

We determined the prevalence of three emergent urogenital mycoplasma species (M. fermentans, M. penetrans, and M. genitalium) in comparison to the most common species (M. hominis and U. urealyticum). M. genitalium is probably the third most frequent agent of nongonococcal urethritis (NGU) in men. It has been suggested that M. fermentans and M. penetrans play a role in the development of AIDS. We analysed the urine and the urethral swab samples from 106 HIV-1 infected individuals (HIV group) and 110 HIV-negative patients with NGU (STD group) by using PCR and culture methods. M. genitalium was detected in 0.9% of the urine and in 1.9% of the urethral samples from the HIV group, compared to 9.1% found only in urethral swab samples from the STD group. M. fermentans was detected in 5.7% urethral swabs from the HIV group and in 0.9% from the STD group. M. penetrans was detected in 6.6% urine samples from the HIV group. M. hominis and U. urealyticum showed infection rates of 7.5 and 18.9% in the HIV group, and 0.9 and 13.6% in the STD group. Overall there was a higher prevalence of mycoplasmas in the HIV group than in the STD group, but the significance of these results remains unclear.

Adult↗
PubMed1999

Interactions between mycoplasma lipoproteins and the host immune system.

Mycoplasmas typically have a number of distinct lipoproteins anchored on the outer face of the plasma membrane. These surface antigens have a potent modulin activity and are preferential targets of the host immune response. However, the variation of some of these lipoproteins provides mycoplasmas with an effective means of evading the host immune defence system.

Humans↗
PubMed1999

Phase variations of the Mycoplasma penetrans main surface lipoprotein increase antigenic diversity.

Mycoplasma penetrans is a recently identified mycoplasma, isolated from urine samples collected from human immunodeficiency virus (HIV)-infected patients. Its presence is significantly associated with HIV infection. The major antigen recognized during natural and experimental infections is an abundant P35 lipoprotein which, upon extraction, segregates in the Triton X-114 detergent phase and is the basis of M. penetrans-specific serological assays. We report here that the P35 antigen undergoes spontaneous and reversible phase variation at high frequency, leading to heterogeneous populations of mycoplasmas, even when derived from a clonal lineage. This variation was found to be determined at the transcription level, and although this property is not unique among the members of the class Mollicutes, the mechanism by which it occurs in M. penetrans differs from those previously described for other Mycoplasma species. Indeed, the P35 phase variation was due neither to a p35 gene rearrangement nor to point mutations within the gene itself or its promoter. The P35 phase variation in the different variants obtained was concomitant with modifications in the pattern of other expressed lipoproteins, probably due to regulated expression of selected members of a gene family which was found to potentially encode similar lipoproteins. M. penetrans variants could be selected on the basis of their lack of colony immunoreactivity with a polyclonal antiserum against a Triton X-114 extract, strongly suggesting that the mechanisms involved in altering surface antigen expression might allow evasion of the humoral immune response of the infected host.

Amino Acid Sequence↗