Biomedical subjects

S Robineau

Publications and source records attributed to S Robineau.

35 records · Page 2Linked to original sources

PubMed1998

Treatment of detrusor sphincter dyssynergia by transperineal injection of botulinum toxin.

Detrusor-sphincter dyssynergia is an involuntary contraction of the external urethral sphincter during the detrusor contraction. It causes voiding dysfunction and can lead to urologic complications such as hydroureteronephrosis and renal failure. Patients with spinal cord injuries are particularly vulnerable. Botulinum toxin has been used via cystoscopy to decrease the activity of the external urethral sphincter. This report describes the treatment of 5 tetraplegic patients by single transperineal injections of botulinum toxin for detrusor-sphincter dyssynergia, proved by a urodynamic study with electromyography. A total of 15 injections was given, resulting in improved bladder function in all patients. Urodynamic assessment after treatment showed an increase of the functional detrusor capacity and a decrease of the maximal detrusor pressure during voiding. These results confirm the consideration of botulinum toxin as a treatment for detrusor sphincter dyssynergia. A single transperineal injection is a valuable, less invasive treatment using a cystoscopic technique.

Adult↗

PubMed1998

Influence of urinary management on urologic complications in a cohort of spinal cord injury patients.

OBJECTIVE: To study urologic complications in patients with spinal cord injury (SCI) in relation to their bladder management. DESIGN AND SETTING: A cohort study of patients with SCI in a rehabilitation center. PARTICIPANTS: One hundred eighty-two patients were studied; demographic data, disease characteristics, and urologic history were obtained for each. INTERVENTION: Patients responding to a questionnaire were given a clinical exam. Their medical records were reviewed, with particular attention given to the following urologic complications: lithiasis, urinary infections, orchiepididymitis, urethral trauma, vesicorenal reflux, and renal failure. RESULTS: Results are reported for 123 patients. Time since SCI was 8 years. Intermittent catheterization was the main method of bladder management. Only 32 patients had changed their method of vesical voiding. Urinary complications had developed in 75% of patients. The most common complication was urinary infection. Vesicoureteral reflux occurred in 26% of patients using percussion. Trauma related to catheterization was the main problem with intermittent catheterization, responsible for a high rate of orchiepididymitis. CONCLUSION: Intermittent catheterization is the most-used method of bladder management, but with a nonnegligible rate of urethral trauma in men. Percussion and Credé maneuver appear to be acceptable techniques of bladder management if the patient is closely monitored.

Adult↗

PubMed1998

Overexpression of the ARF1 exchange factor ARNO inhibits the early secretory pathway and causes the disassembly of the Golgi complex.

The small GTPase ARF1 is a key regulator of intracellular membrane traffic. In its active, GTP-bound form, ARF1 is associated with Golgi membranes and promotes the recruitment of the cytosolic coat protein complex, which will result in membrane budding and vesicle formation. ARNO (ARF nucleotide site opener) has been shown to act in vitro as a GTP exchange factor for ARF1. Here, we have investigated the function of ARNO in vivo. By immunofluorescence and cell fractionation, ARNO was found to be mostly cytosolic in HeLa cells. Its overexpression led to a strong inhibition of the secretion of SEAP (secreted form of alkaline phosphatase). Newly synthesized SEAP failed to acquire endoglycosidase H resistance, indicating a block in the early secretory pathway. This effect on secretion was accompanied by a disassembly of the Golgi complex and a redistribution of Golgi resident proteins into the endoplasmic reticulum (ER). On the other hand, ARNO overexpression did not affect the early endocytic pathway. These results show that ARNO functions in vivo in Golgi to ER transport. Its behavior is then consistent with ARNO being an exchange factor for ARF1.

ADP-Ribosylation Factor 1↗

PubMed1997

Role of protein-phospholipid interactions in the activation of ARF1 by the guanine nucleotide exchange factor Arno.

Arno is a 47-kDa human protein recently identified as a guanine nucleotide exchange factor for ADP ribosylation factor 1 (ARF1) with a central Sec7 domain responsible for the exchange activity and a carboxyl-terminal pleckstrin homology (PH) domain (Chardin, P., Paris, S., Antonny, B., Robineau, S., Béraud-Dufour, S., Jackson, C. L., and Chabre, M. (1996) Nature 384, 481-484). Binding of the PH domain to phosphatidylinositol 4,5-bisphosphate (PIP2) greatly enhances Arno-mediated activation of myristoylated ARF1. We show here that in the absence of phospholipids, Arno promotes nucleotide exchange on [Delta17]ARF1, a soluble mutant of ARF1 lacking the first 17 amino acids. This reaction is unaffected by PIP2, which suggests that the PIP2-PH domain interaction does not directly regulate the catalytic activity of Arno but rather serves to recruit Arno to membranes. Arno catalyzes the release of GDP more efficiently than that of GTP from [Delta17]ARF1, and a stable complex between Arno Sec7 domain and nucleotide-free [Delta17]ARF1 can be isolated. In contrast to [Delta17]ARF1, full-length unmyristoylated ARF1 is not readily activated by Arno in solution. Its activation requires the presence of phospholipids and a reduction of ionic strength and Mg2+ concentration. PIP2 is strongly stimulatory, indicating that binding of Arno to phospholipids is involved, but in addition, electrostatic interactions between phospholipids and the amino-terminal portion of unmyristoylated ARF1GDP seem to be important. We conclude that efficient activation of full-length ARF1 by Arno requires a membrane surface and two distinct protein-phospholipid interactions: one between the PH domain of Arno and PIP2, and the other between amino-terminal cationic residues of ARF1 and anionic phospholipids. The latter interaction is normally induced by insertion of the amino-terminal myristate into the bilayer but can also be artificially facilitated by decreasing Mg2+ and salt concentrations.

ADP-Ribosylation Factor 1↗

PubMed1997

Suppressors of cis-acting splicing-deficient mutations that affect the ribozyme core of a group II intron.

Many of the cis-dominant mutations that lead to respiratory deficiency by preventing maturation of specific yeast mitochondrial transcripts are found to affect the ribozyme core of group I and group II introns. We have searched for suppressors of mutations in the ribozyme-encoding sections of a group II intron, the first intron in the COX1 gene of Saccharomyces cerevisiae, which was independently subjected to in vitro site-directed mutagenesis. Three of the original mutants bore multiple mutations, which act synergistically, since for most individual mutations, suppressors could be obtained that ensured at least partial recovery of respiratory competence and splicing. Out of a total of ten suppressor mutations that were identified, three were second-site substitutions that restored postulated base-pairings in the ribozyme core. Remarkably, and as is observed for group I introns, at least half of the cis-dominant mutations in the first two group II introns of the COX1 gene affect sites that have been shown to participate in RNA tertiary interactions. We propose that this bias reflects cooperativity in the formation of ribozyme tertiary but not secondary structure, on the one hand, and the need for synergistic effects in order to generate a respiratory-deficient phenotype in the laboratory on the other. Finally, a novel in vivo splicing product of mutant cells is attributed to bimolecular splicing at high concentrations of defective transcripts.

Base Sequence↗

PubMed1996

A human exchange factor for ARF contains Sec7- and pleckstrin-homology domains.

The small G protein ARF1 is involved in the coating of vesicles that bud from the Golgi compartments. Its activation is controlled by as-yet unidentified guanine-nucleotide exchange factors. Gea1, the first ARF exchange factor to be discovered in yeast, is a large protein containing a domain of homology with Sec7, another yeast protein that is also involved in secretion. Here we characterized a smaller human protein (relative molecular mass 47K) named ARNO, which contains a central Sec7 domain that promotes guanine-nucleotide exchange on ARF1. ARNO also contains an amino-terminal coiled-coil motif and a carboxy-terminal pleckstrin-homology (PH) domain. The PH domain mediates an enhancement of ARNO exchange activity by negatively charged phospholipid vesicles supplemented with phosphatidylinositol bisphosphate. The exchange activity of ARNO is not inhibited by brefeldin A, an agent known to block vesicular transport and inhibit the exchange activity on ARF1 in cell extracts. This suggests that a regulatory component which is sensitive to brefeldin A associates with ARNO in vivo, possibly through the amino-terminal coiled-coil. We propose that other proteins with a Sec7 domain regulate different members of the ARF family.

ADP-Ribosylation Factor 1↗

PubMed1996

Sequence of a 39,411 bp DNA fragment covering the left end of chromosome VII of Saccharomyces cerevisiae.

We have sequenced a DNA fragment of 39,411 bp which includes part of the left telomere of chromosome VII of Saccharomyces cerevisiae. We have identified 19 open reading frames (ORFs); six correspond to known yeast genes (ADH4, FZF1, HKB, RTG2, HFM1 and PDE1), nine have similarity with other genes and four exhibit no significant similarity with any known gene. The average size of these ORFs seems to be related to their location, the eight ORF's nearest the telomere being shorter than the 11 others. These two groups of genes are separated by a region of 4.5 kb devoid of significant ORFs. One ORF, NRF120, is a new member of the seripauperine family, represented once in all sequenced yeast chromosomes, in a subtelomeric location.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1995

Mutations in the mitochondrial split gene COXI are preferentially located in exons: a mapping study of 170 mutants.

We have analysed the precise location of a large number (170) of mutations affecting the structural gene for subunit I of the cytochrome c oxidase complex. This gene, COXI, is 12.9 kb long and the major part of the sequence (i.e. 11.3 kb) is composed of introns. Several conclusions can be drawn from this study: (1) A significant proportion (84/170) of the mutations cannot be assigned to a single position within the gene by deletion mapping, in spite of clearly being located in it. These mutations are probably large deletions or multiple mutations. (2) Four mutants carry distant double mutations, which have been individually localized. (3) Eighty-two mutants have lesions that are restricted to very short regions of the gene and we therefore conclude that they are most probably due to single hits; amongst these single mutations, 41 are unambiguously located in exons and 28 in introns. This result implies that, at least in this particular split gene, the probability of selection of a mutant phenotype in an exon is, on the average, 13.3 times greater than in an intron, in spite of the existence, within most of these introns, of open reading frames specifying intronic proteins. The evolutionary significance and biological implications of these results are discussed.

Base Sequence↗

PubMed1995

The reflex sympathetic dystrophy syndrome in patients who have had a spinal cord injury.

Patients suffering from a spinal cord injury often present with a pain syndrome. Although the reflex sympathetic syndrome is a common diagnosis in some forms of neurological disease such as patients with a stroke, it is less frequent in those with a spinal lesion. The authors report eight patients with reflex sympathetic dystrophy who had a spinal cord injury. The diagnosis and treatment are discussed along with a review of literature.

Adult↗

PubMed1994

[Urination disorders in multiple sclerosis: value of urodynamic assessment].

Urinary troubles are common in patients with multiple sclerosis. The management of these troubles requires an accurate analysis. Urodynamic assessment was preformed in 117 patients with urinary symptoms positively diagnosed as suffering from multiple sclerosis. Urinary symptoms are not always correlated to urodynamic patterns. We have studied the correlation between urinary symptoms and urodynamic findings. Urodynamic results are similar to most of previous series: detrusor hyperreflexia is the most frequent abnormality, detrusor sphincter dyssynergia is diagnosed in 50% of the patients. There is some correlations with symptoms, but there are insufficient for an accurate diagnosis. Postvoid residue for urinary tracts infectious diseases, and sphincter incompetence for urinary incontinence are the main risk factors.

Adult↗

PubMed1994

[Heterotopic ossification and vascular compression].

Heterotopic ossification is common in patients with spinal cord or brain injury. Whereas the articular complications of heterotopic ossification have been well documented, the vascular complications are less well known. We report three cases with vascular compression and discuss the diagnosis and treatment in the light of a review of the literature.

Adult↗

PubMed1992

The unusual reversion properties of a mitochondrial mutation in the structural gene of subunit I of cytochrome oxidase of Saccharomyces cerevisiae reveal a probable histidine ligand of the redox center.

We have analyzed a mutation in the mitochondrial gene oxi3 coding for subunit I of cytochrome-oxidase in the yeast Saccharomyces cerevisiae. This mutation replaces one of the seven invariant histidines of the polypeptide (position 378) by a tyrosine, and leads to a respiratory deficient phenotype. A total of 157 revertants, which have recovered the ability to grow on a respiratory substrate, have been selected from this mutant (tyrosine 378). The nature of the reversion has been analysed by a rapid screening procedure and 32 of the revertants have been sequenced. They are all true back-mutations reintroducing the histidine in position 378. This very exceptional situation suggests that this histidine is a ligand of the redox center of cytochrome oxidase.

Amino Acid Sequence↗

PubMed1989

The differential overamplification of short sequences in the mitochondrial DNA of rho- petites in Saccharomyces cerevisiae stimulates recombination.

It is well known that the yeast Saccharomyces cerevisiae can be affected by mutations, called 'petite colonie', which correspond to the loss of the major part of the mitochondrial DNA and the concomitant amplification of the remaining sequence, the basic repeat unit (BRU). We describe here a new phenomenon, the internal overamplification (IOA), due to the differential amplification (up to 20-fold) of short sequences within the BRU. These IOAs are very stable and stimulate the recombination. We discuss here the possible mechanisms giving rise to the appearance and maintenance of the IOAs within the BRU and their effect on the recombination process.

Base Sequence↗

PubMed1986

Expression of the mitochondrial split gene coding for cytochrome oxidase subunit I in S. cerevisiae: RNA splicing pathway.

We have studied the splicing pathway leading to the synthesis of cytochrome oxidase subunit I (COX I) mRNA, by analysing the transcription pattern of several oxi3- splicing deficient mutants located in the first four introns of the gene. The four introns contain long open reading frames (ORFs) in phase with the upstream exons. All the mutations block the excision of the mutated intervening sequence (IVS) from the pre-mRNA, and accumulate characteristic novel polypeptides of sizes which could correspond to the translation products of the intron's ORF. Most of the mutations do not affect the splicing of the following intervening sequences; only in the case of mutations in the aI1 intron is a polar effect observed on the splicing of the second intron, aI2. Our results indicate that the splicing of these two intervening sequences which both belong to the class II of introns described by Michel et al. (1982), is controlled by the activity of the maturases encoded by their respective ORFs and that the translation of the aI2 maturase depends on the previous excision of aI1 IVS. (Moreover, the aI1 maturase, which accumulates in some mutants, can efficiently splice aI2 IVS when the translation of the latter's proper maturase cannot occur).

Electron Transport Complex IV↗

PubMedDate not supplied

Sequence analysis of three deficient mutants of cytochrome oxidase subunit I of Saccharomyces cerevisiae and their revertants.

Three respiratory-deficient mutants of cytochrome oxidase subunit I in the yeast mitochondrion have been sequenced. They are located in, or near, transmembrane segment VI, the catalytic core of the enzyme. Respiratory-competent revertants have been selected and studied. The mutant V244M was found to revert at the same site in valine (wild-type), isoleucine or threonine. The revertants of the mutant G251R were of three types: glycine (wild-type), serine and threonine at position 251. A search for second-site mutations was carried out but none were found. Among 60 revertants tested, the mutant K265M was found to revert only to the wild-type allele.

Amino Acid Sequence↗

PubMedDate not supplied

[Presentation for the use of a clinical laboratories of standards of metrology (Document A)].

Clinical laboratories shall have a perfect control of "in vitro diagnostic medical devices" to ensure the quality of their analytical results. This introductory presentation to a serie of documents of recommendations tackles the different standards of metrology concerning the requirements to reference materials, metrological traceability, metrological confirmation, management of measurement as well as uncertainty of measurement. The standards concerning clinical laboratories are then succinctly described.

Clinical Laboratory Techniques↗

PubMedDate not supplied

[Recommendations for the installation in the laboratory of metrological functions and corresponding documentation (Document B)].

In order to ensure the quality of analytical results, clinical laboratories shall have a perfect control of process and equipments of measurement. Therefore is recommended individualisation of metrological function, generally entrusted the quality manager. This quality manager will draw up a metrological traceability, verifications and confirmations, control of non conformities, follow-up and evaluation of metrological function.

Clinical Chemistry Tests↗