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J Masson

Publications and source records attributed to J Masson.

At least 19 recordsLinked to original sources
PubMed2003

A randomized trial comparing heater probe plus thrombin with heater probe plus placebo for bleeding peptic ulcer.

BACKGROUND & AIMS: This multicenter, double-blind, controlled trial compared the efficacy of combined endoscopic hemostatic treatment using the heater probe plus thrombin injection with that of the heater probe plus placebo injection as treatment for peptic ulcers with active bleeding or nonbleeding visible vessels. Efficacy was defined in terms of primary hemostasis, prevention of rebleeding, and need for urgent surgery. METHODS: Two hundred forty-seven patients presenting with major peptic ulcer bleeding were randomized to heater probe plus thrombin or to heater probe plus placebo. The groups were well matched for all risk categories including age, endoscopic stigmata, shock, and severity of comorbid diseases. Endoscopic therapy was applied using the heater probe followed by injection of thrombin or placebo. RESULTS: Successful primary hemostasis was achieved in 97% of patients. Rebleeding developed in 19 (15%) of thrombin plus heater probe patients and 17 (15%) of placebo plus heater probe patients. Emergency surgery was necessary in 16 and 13 patients, respectively. Eight patients in the thrombin group had adverse events compared with 4 in the placebo group. Eight (6%) of thrombin plus heater probe patients and 14 (12%) of placebo plus heater probe patients died (P = 0.21). CONCLUSIONS: The combination of thrombin and the heater probe does not confer an additional benefit over heater probe and placebo as endoscopic treatment for bleeding peptic ulcer. Our trial does not support the use of this combination of hemostatic therapy.

Adult↗
PubMed2000

Ontogeny of Rxt1, a vesicular "orphan" Na(+)/Cl(-)-dependent transporter, in the rat.

The developmental expression of the orphan Na(+)/Cl(-)-dependent transporter, Rxt1, was studied in the rat using a specific [(35)S]complementary RNA probe and affinity purified antibodies. Western blotting experiments allowed the detection of Rxt1 in brain as early as on embryonic day 16. After birth, the brain levels of Rxt1 increased dramatically up to a maximum around postnatal day 30 and then decreased slightly to the adult value. In situ hybridization experiments allowed the earliest detection of Rxt1 messenger RNA in the brain and spinal cord at embryonic day 14. In embryonic day 18 embryos, Rxt1 messenger RNA was present not only in the nervous system but also in the pituitary, the thymus and the heart. Immunoautoradiograms of whole embryo at embryonic days 16 and 18 showed high amounts of the Rxt1 protein in the spinal cord and brain. Moreover, at embryonic day 18, the orphan transporter was expressed in the thymus, heart and liver. At these ages, Rxt1 immunolabeling was localized in neurons of the subplate and in the ventricular zone of the brain. During early postnatal stages, Rxt1 messenger RNA expression demonstrated dynamic and complex changes until postnatal day 13. In particular, this transcript was relatively abundant in the striatum at postnatal days 3 and 5 and then decreased to very low levels after postnatal day 10. At the same period, Rxt1 immunostaining in the hippocampus and the cerebral cortex was observed all over the gray matter, in cell bodies as well as in the neuropil. Finally, the adult pattern was reached around postnatal day 13 for Rxt1 messenger RNA, but only at postnatal day 20 for the Rxt1 protein. The presence of Rxt1 messenger RNA and protein at embryonic stages and the high expression of the protein during synaptogenesis suggest that this vesicular "orphan" transporter is involved in the brain maturation process.

Aging↗
PubMed1999

Characterization and distribution of Hxt1, a Na(+)/Cl(-)-dependent orphan transporter, in the human brain.

Rxt1, a transporter-like protein structurally related to the large family of Na(+)/Cl(-)-dependent carriers, was isolated from the rat brain. In the present study, Hxt1, the homologue of Rxt1, was isolated from human cortex cDNA. Comparison of their respective nucleotidic sequences revealed a 96% conservation between Hxt1 and Rxt1. Genetic mapping with human genome radiation hybrids allowed the location of the gene coding for Hxt1 between 323ya5 and 084xb3 AFM markers, on a portion of chromosome 1p which spans over 7 cM or 118 cRay. Northern blot analyses demonstrated that Hxt1 mRNA ( approximately 7.5 Kb) is expressed in the human brain but not in peripheral tissues. The immunodistribution of Hxt1 was determined with antibodies raised against the C-terminus of Rxt1. Hxt1 is concentrated in the cerebral cortex, caudate-putamen, substantia nigra, hippocampus, and cerebellum, appearing as a diffuse or a punctate labeling at the light microscope level. This regional and cellular distribution suggests that Hxt1, as its rat homologue, could be present in axon terminals of glutamatergic neurons. The high pressure of selection exerted upon this protein, its strategic anatomical and subcellular distributions suggest that this orphan transporter could be involved in critical functions in the central nervous system.

Amino Acid Sequence↗
PubMed1999

Involvement of Arabidopsis thaliana ribosomal protein S27 in mRNA degradation triggered by genotoxic stress.

A recessive Arabidopsis mutant with elevated sensitivity to DNA damaging treatments was identified in one out of 800 families generated by T-DNA insertion mutagenesis. The T-DNA generated a chromosomal deletion of 1287 bp in the promoter of one of three S27 ribosomal protein genes (ARS27A) preventing its expression. Seedlings of ars27A developed normally under standard growth conditions, suggesting wild-type proficiency of translation. However, growth was strongly inhibited in media supplemented with methyl methane sulfate (MMS) at a concentration not affecting the wild type. This inhibition was accompanied by the formation of tumor-like structures instead of auxiliary roots. Wild-type seedlings treated with increasing concentrations of MMS up to a lethal dose never displayed such a trait, neither was this phenotype observed in ars27A plants in the absence of MMS or under other stress conditions. Thus, the hypersensitivity and tumorous growth are mutant-specific responses to the genotoxic MMS treatment. Another important feature of the mutant is its inability to perform rapid degradation of transcripts after UV treatment, as seen in wild-type plants. Therefore, we propose that the ARS27A protein is dispensable for protein synthesis under standard conditions but is required for the elimination of possibly damaged mRNA after UV irradiation.

Amino Acid Sequence↗
PubMed1999

Immunocytochemical evidence of vesicular localization of the orphan transporter RXT1 in the rat spinal cord.

Rxt1, a member of the Na+/Cl- orphan transporter family, exhibits numerous features suggesting a role as plasma membrane transporter. Despite numerous attempts, its substrate has not yet been identified, although immunocytochemical studies have shown that Rxt1 distribution generally matches that of glutamate or GABA. In order to further characterize Rxt1, its detailed immunocytochemical distribution in the rat spinal cord and dorsal root ganglia was studied at both light microscope and ultrastructural levels. The widespread distribution of Rxt1 in spinal cord and ganglia cannot be correlated with any known classical or peptidergic transmitter. Rxt1 is expressed in a subpopulation of glutamatergic primary afferent fibers, in large and medium-sized ganglion cells, while small glutamate cells exhibit generally no Rxt1-like immunoreactivity. In the spinal cord, Rxt1-immunoreactive cell body distribution is quite ubiquitous since Rxt1 is expressed in all laminae in various neuronal types like interneurons, some projection neurons and motoneurons. Some of these neurons are cholinergic. At the electron microscope level, the peroxidase labeling was never localized to the plasma membrane, but rather associated with different organelles including the outer membrane of small synaptic vesicles and large granular vesicles. This localization resembles that of vesicular transporters detected with the same method and suggests that Rxt1, in contrast to other Na+/Cl- transporters, is expressed on vesicles. This was confirmed using a pre-embedding silver-intensified colloidal gold method. Indeed, most gold particles appeared to be localized into the axoplasm on synaptic vesicle accumulations; only few gold particles were observed close to the plasma membrane. These results suggest that Rxt1, despite its molecular characteristics predicting a plasma membrane localization, might be a vesicular transporter.

Animals↗
PubMed1999

Unexpected localization of the Na+/Cl--dependent-like orphan transporter, Rxt1, on synaptic vesicles in the rat central nervous system.

Numerous features of its primary structure demonstrate that the orphan transporter Rxt1 belongs to the Na+/Cl--dependent neurotransmitter plasma membrane transporter superfamily, which includes the dopamine, norepinephrine, serotonin and gamma-aminobutyric acid (GABA) transporters. Initial immunocytochemical investigations with affinity-purified antibodies have established that Rxt1 is localized, almost exclusively, in axon terminals of glutamatergic neurons and subsets of GABAergic neurons in the CNS. Further studies were carried out to determine its subcellular distribution. In a first series of experiments, PC-12 cells were transfected with plasmids encoding either the dopamine transporter or Rxt1. Immunofluorescence experiments showed that the dopamine transporter was expressed in these cells, and, as expected, addressed to their plasma membrane. Surprisingly, this was never the case with Rxt1, which was targeted to the same subcellular compartment as synaptophysin, a vesicular protein. In a second set of experiments, subcellular fractionation of rat striatum showed that Rxt1, but not the dopamine transporter, was relatively abundant in the purified synaptic vesicle fraction. Finally, electron microscopic immunocytochemistry with anti-Rxt1 antibodies showed peroxidase as well as pre- and post-embedding immunogold labelling confined to the intracellular compartment in various brain regions. Moreover, quantitative analysis of post-embedding experiments demonstrated that the immunogold particles corresponding to Rxt1 immunoreactivity were mostly localized to small synaptic vesicles. These data indicate that, in contrast with the other members of the Na+/Cl--dependent neurotransmitter transporter superfamily, which are targeted to the plasma membrane, Rxt1 is distributed as a vesicular protein in the CNS.

Animals↗
PubMed1999

The "orphan" Na+/Cl(-)-dependent transporter, Rxt1, is primarily localized within nerve endings of cortical origin in the rat striatum.

Previous studies have shown that the striatum expresses very low levels of Na+/Cl(-)-dependent "orphan" transporter Rxt1 transcripts but contains high levels of protein. This study investigated the origin of Rxt1 expression in rat striatum. Striatal Rxt1 contents assessed by immunocytochemistry or western blotting were found to be significantly reduced after corticostriatal denervation but not after striatal or thalamic lesion with kainic acid or selective 6-hydroxydopamine-induced nigrostriatal deafferentation. Corticostriatal neurons retrogradely labeled by intrastriatal fluorogold injections were shown to express Rxt1 mRNA. Combination of anterograde biotin-dextran amine labeling of the corticostriatal pathway with Rxt1 immunogold detection at the ultrastructural level demonstrated the presence of Rxt1 in about one-third of the corticostriatal synaptic terminals and in numerous unidentified synaptic terminals. All the Rxt1-positive terminals formed asymmetrical contacts on spines. These data provide evidence that striatal Rxt1 immunoreactivity is mainly of extrinsic origin and more specifically associated with the corticostriatal pathway. Rxt1 appears as a selective presynaptic marker of synapses formed by presumably excitatory amino acid afferents, but it segregates a subclass of these synapses, thereby revealing a functional heterogeneity among excitatory amino acid systems.

Afferent Pathways↗
PubMed1999

[Breast reconstruction by inflatable anatomical implant. Retrospective study of 65 cases].

This study reports the first mammary reconstruction series with anatomic saline implants after mastectomy for breast cancer. 65 patients were reviewed with a 10-month follow-up. The authors used Mac Gahn anatomic saline implant style 468 or 363. The contralateral breast mammaplasty for symmetrisation was performed in 53 patients, usually during implantation of the implant. The nipple areola reconstruction was usually performed with full thickness' skin graft and Little's flap. The implants, (average volume of 275 ml before changing), were changed for 17 patients, because of insufficient reconstruction or an excessively high mammary fold. The most frequent complication was pain, despite morphine protocols (19 patients). These were a cases of 9 rippling; but only a small percentage of internal dimple (4 patients). Patient and surgeon satisfaction was rated (1-20) and classified into three levels. In conclusion, the advantages of anatomic saline implants are: to avoid some symmetrisations, reconstruction of a stable breast, to avoid internal dimple. The disadvantages are: persistent rippling, specific learning for their implantation and difficulty of the choice of size.

Adult↗
PubMed1998

[Spheno-mandibular ankylosis. A case].

A rare case of spheno-mandibular ankylosis is reported in a 12 year-old child. The patient only complained of a restricted mouth opening; no particular etiologic factors were found to explain what was perhaps a myositis ossificans of the pterygoid muscles. However, neither the anatomic presentation at surgery, nor the histologic findings could confirm this diagnosis. An intra-oral route was chosen for the ankylosis resection, and the reconstruction of the resected upper part of the ramus was performed by a costo-chondral graft. The patient was free of recurrence 3 years after follow up.

Ankylosis↗
PubMed1997

Distribution pattern and ultrastructural localization of Rxt1, an orphan Na+/Cl(-)-dependent transporter, in the central nervous system of rats and mice.

The cellular and subcellular localization of Rxt1 protein, an orphan Na+/Cl(-)-dependent transporter, was investigated in the central nervous system of rats and mice, with rabbit polyclonal antibodies specifically directed against its C-terminal region. At the light microscope level, the distribution of Rxt1, visualized by the immunoperoxidase method, was found to be similar in rats and mice. Labelled elements were present in numerous gray matter regions of the central nervous system, from the olfactory bulb to the spinal cord. In all labelled regions, immunoreactivity was confined to the neuropil where both a diffuse labelling of low intensity and an intense punctate staining were noted. To further identify the nature of the cellular elements bearing the punctate staining, possible changes in this labelling pattern were investigated: (i) in deep cerebellar nuclei and lateral vestibular nucleus of the Lurcher mutant mouse, in which all cerebellar Purkinje cells are missing and (ii) in the rat cervical spinal cord, 10 days after multiple resections of dorsal roots. The vast majority of the punctate structures, delineating the neuronal perikaryal and stem dendritic contours, had disappeared in the mutant mouse, providing evidence that they belong to Purkinje cell axon terminals. In rhizotomized rats, the intense labelling in laminae I and III had disappeared, demonstrating that it occurred in subclasses of axonal projections of primary afferent fibres. These results strongly suggest that Rxt1 is present in presynaptic axon terminals. The electron microscopic study was carried out in the hippocampus, cerebellum and lateral vestibular nucleus of control mice, where Rxt1-labelled punctate structures were found to be abundant. Immunostaining was confined to axon terminals, particularly in hippocampal and cerebellar mossy fibres and in Purkinje cell axonal terminations of the cerebellar deep nuclei and lateral vestibular nucleus. In the cerebellar cortex, axon terminals belonging to inhibitory local circuit neurons (basket and Golgi cells), were free of labelling. The observations reported in this study have shown that: (1) The Rxt1 transporter is neuron-specific, and is expressed by only some classes or even subclasses of neuronal systems. (2) This transporter can be encountered in excitatory axons using glutamate as neurotransmitter (hippocampal and cerebellar mossy fibres: primary afferent fibres), as well as in inhibitory axons known by their GABAergic nature (Purkinje cell axon terminals) where it might be involved in the re-uptake process of one or several molecules released from corresponding terminals.

Animals↗
PubMed1997

[Rectus abdominis free flap breast reconstruction. A series of 23 cases].

Free TRAM flap breast reconstruction was performed in 23 patients from july 1993 through november 1995 at the Saint-Louis Hospital in Paris. The surgical team was composed of eight different surgeons. In all cases a delayed breast reconstruction procedure was performed. All patients in this series had previously received radiation therapy and 82.6% patients presented with excess body weight. Decision to perform a free flap procedure was confirmed peroperatively under two conditions. Adequate caliber of the donor and recipient vessels was required, allowing the anastomoses to be performed without magnification in most cases. Preservation of the thoraco-dorsal vessels was the rule so as to allow later use of a latissimus dorsi flap if necessary. Thus in 8 of the 31 cases in which a free flap was initially indicated a pedicled flap was actually performed so as to satisfy the above conditions. All procedures were performed by two surgical teams working simultaneously. Flap harvest met local tissue requirements in all cases. A lateral strip of rectus abdominis muscle and fascia was preserved when this appeared feasible. The abdominal wall was reinforced by prosthetic means in 82.6% of cases. The average operative time was 9 hours. Results were considered satisfactory or very satisfactory in most cases. The complication rate was 39.1%. Among the complications noted were 1 case of partial flap necrosis, 1 case of fat necrosis, 1 abdominal hernia, 1 abdominal bulge (both abdominal complications occurred in patients in whom no prosthetic material was used for abdominal repair). This complication rate also includes revision of the microsurgical anastomoses in 2 cases; in both cases the flap survived completely. This study tends to suggest that the free TRAM flap for breast reconstruction is a reliable technique. It is the authors' belief that it should replace the bipedicled TRAM flap since it combines ample flap vascularization with minimal rectus harvest.

Adult↗
PubMed1996

Plasma nitrate concentration in infective gastroenteritis and inflammatory bowel disease.

BACKGROUND: In subjects on a low nitrate diet, plasma nitrate concentration and urinary nitrate excretion are thought to reflect endogenous nitric oxide (NO) production, and have been reported to increase during infective and inflammatory bowel disease. AIMS: To compare the extent of NO production in patients with infective versus non-infective forms of bowel dysfunction. SUBJECTS: Four groups: 20 healthy, volunteer clerical and laboratory staff, 12 patients with irritable bowel syndrome, 19 patients with inflammatory bowel disease, and 20 patients with infective gastroenteritis. METHODS: The plasma nitrate concentration was determined with a copper coated cadmium column and spectrophotometry. Mean and median plasma nitrate concentrations were calculated and compared within the four groups. Mann-Whitney distribution free rank testing was used to compare the median values. RESULTS: Median plasma nitrate concentrations in the four groups were: controls 32.7 mumol/l; irritable bowel syndrome 35.5 mumol/l; inflammatory bowel disease 35.1 mumol/l; and gastroenteritis 117.9 mumol/l (p < 0.001 gastroenteritis v all other groups). CONCLUSIONS: Plasma nitrate concentration could serve as a discriminant between infective and inflammatory or functional bowel disease in patients presenting with diarrhoea. It is not clear why there is considerable difference in endogenous nitrate synthesis in these two conditions, which are both characterised by severe gut inflammation.

Adolescent↗