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P Delmas

Publications and source records attributed to P Delmas.

At least 73 records · Page 4Linked to original sources
PubMed1996

Appearance of neurofilament subunit epitopes correlates with electrophysiological maturation in cortical embryonic neurons cocultured with mature astrocytes.

E14 rat cortical neurons which have almost no glial progenitors were cocultured with a homogeneous population of mature type 1 astrocytes at a 4/1 ratio in serum free medium. Maturation of neurons was evaluated using a set of well characterized antibodies and two new monoclonal antibodies (MN2E4 and MN3H6) raised against various neurofilament subunits and whole-cell patch clamp experiments. We observed that this coculture method leads to a well-timed and very homogeneous neuronal maturation and that sequential appearance of neurofilament subunits in developing neurons correlates with the electrophysiological maturation. This sequence, early expression of the 68 kDa neurofilament subunit and late appearance of the 200 kDa neurofilament subunit, occurs in normal brain development, which validates this culture model as a useful tool for studying neuronal maturation and differentiation. MN2E4 staining (non-phosphorylated 200 kDa cytoskeletal protein antibody) appeared just before the neurons became excitable. It could thus be used as a functional neuronal marker. MN3H6 staining (phosphorylated 160-200 kDa neurofilament subunit antibody) appeared just after the neurons made synaptic contacts and generated synaptically driven spike bursts. This finding indicated that some phosphorylated epitopes of 160-200 kDa neurofilament followed synaptogenesis. These processes may play a key role in stabilizing the synapses to achieve a functional neuronal network.

Animals↗
PubMed1996

Cloning and characterization of the eapB and eapC genes of Cryphonectria parasitica encoding two new acid proteinases, and disruption of eapC.

Two new proteinases secreted by Cryphonectria parasitica, namely EapB and EapC, have been purified. The corresponding structural genes were isolated by screening a cosmid library, and sequenced. Comparison of genomic and cDNA sequences revealed that the eapB and eapC genes contain three and two introns, respectively. The products of the eapB and eapC genes as deduced from the nucleotide sequences, are 268 and 269 residues long, respectively. N-terminal amino acid sequencing data indicates that EapC is synthesized as a zymogen, which yields a mature 206-amino acid enzyme after cleavage of the prepro sequence. Similarly, sequence alignment studies suggest that EapB is secreted as a 203-residue form which shares extensive similarities not only with EapC but also with two other acid fungal proteinases. However, they display distinct structural features; for example, no cysteine residue is found in EapC. The eapC gene was mutated using a two-step gene replacement strategy which allowed the specific introduction of several stop codons at the beginning of the eapC coding sequence in an endothiapepsin-deficient (EapA-) C. parasitica strain. Although the resulting strain did not secrete EapC, it still exhibited residual extracellular proteolytic activity, which could be due to EapB.

Amino Acid Sequence↗
PubMed1996

Osteoporosis prevention clinical study program.

OBJECTIVES: Oestrogens are widely believed to be effective against postmenopausal osteoporosis. However there are some outstanding questions which still need an answer. For example, the minimal effective dose regimen of oestradiol needs to be established and the relationship between oestradiol levels and efficacy on bone turnover and bone mass needs to be further clarified. METHODS: Menorest is being tested in the prevention of postmenopausal bone loss. A phase II/III clinical program, that includes two double blind, dose-ranging, placebo-controlled, parallel group, 2-year studies, has started in 58 centers in Europe and South Africa. Four-hundred eighty women will be enrolled in the two studies (201 and 305). The objective of the studies is to evaluate the efficacy of Menorest at different doses and regimens, in the prevention of bone loss in early postmenopausal women. In study 201, the treatment regimen is 'cyclic sequential' (24 days of transdermal oestradiol during a 28-day cycle with progestin taken during the last 14 days of oestrogen administration). In study 305 the treatment regimen is "continuous sequential' (28 days of transdermal oestradiol during, a 28-day cycle with progestin taken during the last 14 days of oestrogen administration). The doses studied are 50, 75, 100 micrograms/day in study 201, and 25, 50, 75 micrograms/day in study 305, (the two studies are otherwise identical). All 'active-dose' treated groups receive dydrogesterone 20 mg/day during the last 14 days of Menorest administration and placebo tablets are given to the placebo patch group. The main entry criteria are natural or surgical menopause, (with hormonal confirmation) from 1 to 6 years, with no contra-indication to HRT and with a bone mineral density (BMD) at the lumbar spine with a T-score between 0 and -3. Women with severe vasomotor symptoms are excluded from the studies. The primary efficacy variable is the mean change from baseline, measured with dual energy X-ray absorptiometry (DXA) at 2 years, in the lumbar spine BMD (L1-L4). Whole body and hip BMD are also evaluated. Markers of bone turnover (bone-specific alkaline phosphatase, osteocalcin and CrossLaps) are monitored throughout the study. Blood samples are drawn on the third day of patch application at certain visits in order to monitor oestradiol levels and establish any potential correlation with activity on bone (BMD, bone markers). Besides routine safety analysis, lipid profile and coagulation factors are also monitored. Special attention is drawn to endometrial safety with endometrial aspiration or trans vaginal sonography (TVS) performed before study start, after 1 year and at 2 years of treatment. RESULTS: Data presented here refer to 146 patients for whom demographics and clinical data are already available, and to 370 patients for whom baseline DXA data have already been validated. The mean (+/-S.D.) age of the women included in the two studies is 53.4 (+/-3.2) with a menopausal age of 38.3 (+/-19.6) months. None of the women who entered the study had severe postmenopausal symptoms as shown by a mean number of hot flushes of 2.2 (+/-2.6) per day, during the last 14 days before inclusion. The mean (+/-S.D.) lumbar spine (L1-L4) BMD is 0.914 (+/-0.122) g/cm2 which corresponds to a Z-score of -0.26 and a T-score of -1.17. Femoral neck, trochanter and Wards triangle have a BMD which is below the mean of age-matched controls but still within the normal range (Z-scores between 0 and -1). Only the whole body BMD is over the mean of age-matched controls, with a Z-score of 0.32. The in-vivo precision mean (+/-S.D.), was calculated and showed a value of 0.868 (+/-0.872), which can be considered a good performance. CONCLUSIONS: In summary, the use of one of the most recent techniques to assess the bone mineral content/density together with an accurate quality control program on all the densitometers used in the studies will help to improve the in-vivo BMD precision and therefore mak

Administration, Cutaneous↗
PubMed1996

Volvulus of the sigmoid colon as a complication of segmental dilatation of the colon. Report of 2 cases.

Sigmoid volvulus is an unusual cause of intestinal obstruction in children. We report two cases of sigmoid volvulus as a complication of segmental dilatation of the colon occurring in two girls (5 years old and 9 years old) previously treated for chronic constipation. In both cases the constipation had been recognised since the neonatal period mimicking a Hirschsprung's disease, a diagnosis which has been excluded after rectal biopsy. The delayed diagnosis of segmental dilatation of the sigmoid colon followed the volvulus. Segmental colonic resection resulted in both cases in the cure of the constipation.

Child↗
PubMed1996

Muscarinic activation of a novel voltage-sensitive inward current in rabbit prevertebral sympathetic neurons.

The muscarinic activation of rabbit prevertebral sympathetic neurons was studied in non-dissociated coeliac and superior mesenteric ganglia using whole-cell patch-clamp techniques. In the presence of nicotinic blockers, carbachol, muscarine and oxotremorine-M (1-50 microM) induced tonic firing by activating a persistent inward current. These effects were abolished by atropine. They persisted when the M-current was blocked with Ba2+ (1 mM) and intracellular Cs+. The muscarinic inward current was found to be time- and voltage-dependent. It peaked at -60 mV, decreased at large hyperpolarizations and was tonically activated between -110 and -20 mV, which gave steady-state I-V curves an N-shape between -96 and -54 mV. The negative slope accounted for the large hyperpolarizing responses generated by current pulses in carbachol-treated cells. The muscarinic current was abolished when Na+ was replaced by choline, Tris+, sucrose, N-methyl-D-glucamine and Cs+ but not Li+. It was resistant to tetrodotoxin (3 microM), amiloride (3 microM), benzamil (10 microM) and tetraethylammonium (5-20 mM). No involvement of K+ and Cl- could be detected. We therefore styled it INa,M, in reference to its ionic selectivity and its coupling to muscarinic receptors. Low Ca(2+)-Mg2+ salines enhanced the Na,M-current. The current was blocked by Cd2+, Co2+, La3+ (1 mM) and Ba2+ (5 mM) but insensitive to methoxyverapamil hydrochloride, nicardipine, nifedipine and omega-conotoxin MVII A (2-20 microM). These effects were ascribed to the binding of di- and trivalent ions to the Na,M-channels. Spike bursts transiently blocked INa,M. With high intracellular ethylene glycol bis(b-aminoethyl ether)-N,N'-tetraacetic acid or 1,2-bis (2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (20-50 mM), this effect was reduced, whereas INa,M persisted in long-term recordings and its amplitude increased twofold, indicating that intracellular calcium negatively regulated the Na,M-channels. We conclude that we have described a novel muscarinic receptor-coupled channel which appears to play a major part in regulating the firing behaviour of sympathetic neurons.

Animals↗
PubMed1996

Synaptically activated low-threshold muscarinic inward current sustains tonic firing in rabbit prevertebral sympathetic neurons.

Whole-cell patch-clamp experiments were performed on non-dissociated rabbit coeliac sympathetic neurons in the presence of nicotinic blockers. Coeliac neurons were classified as either silent or spontaneously active (pacemaker) cells. Under voltage-clamp conditions, pacemaker cells exhibited a steady-state N-shaped current-voltage relationship due to the presence of a persistent voltage-dependent inward current in the potential range of -100 to approximately -20 mV. This inward current sustained the regular firing activity of pacemaker cells and was absent from quiescent neurons. It disappeared in the presence of tetrodotoxin and in low Ca(2+)-high Mg2+ external solutions and was enhanced by eserine. Splanchnic nerve stimulation induced slow regenerative depolarizations and firing discharges in silent neurons by activating a low-threshold voltage-sensitive inward current. The synaptic current had a U-shaped voltage-dependence from -96 to approximately -20 mV and exhibited the dynamic properties of the muscarinic voltage-dependent inward current INa,M. It gave the current-voltage relationship an N shape similar to that observed in spontaneously active cells. The muscarinic antagonists atropine and pirenzepine abolished the inward current present in pacemaker cells and that induced by nerve stimulation in silent neurons. These data provide evidence that both spontaneous firing activity and nerve-evoked depolarizing responses in coeliac neurons are sustained by the activation of the muscarinic Na,M current. The tonic activation of INa,M in spontaneously firing cells results from a sustained Ca(2+)-dependent tetrodotoxin-sensitive release of acetylcholine. This study provides evidence that the role of the muscarinic receptors is not purely a neuromodulatory one, but that these receptors are directly involved in ganglionic neurotransmission.

Animals↗
PubMed1996

[Value of endoscopic incisions in the treatment of ureteroceles in children].

Endoscopic incision is a simple method to provide decompression of the urinary tract above ureteroceles. This technique has been used in most cases of ureterocele seen since 1987. In 6 cases of ureterocele in a single system good results were achieved in all cases. In 13 cases of ureterocele in a duplex system, incision was the only procedure in 5 patients. Seven patients required further surgery : upper pole partial nephrectomy when dilatation persisted, ureteral reimplantation and ureterocele excision in cases of upper pole reflux, secondary to the endoscopic incision, or in cases of persistent reflux in the lower pole ureter. Endoscopic incision is a safe treatment in cases of intravesical ureterocele (single system or duplex system) but in the cases of ectopic ureteroceles, it generally provides only temporary benefit. In these cases, it facilitates delayed lower urinary tract surgery.

Age Factors↗
PubMed1995

Secretion and maturation study of endothiapepsin in Saccharomyces cerevisiae. A first step toward improving its substrate specificity.

The gene encoding endothiapepsin (EAP), an extracellular aspartic proteinase from the filamentous ascomycete Cryphonectria parasitica, was expressed into Saccharomyces cerevisiae. Efficient secretion of an active and correctly processed enzyme was achieved when expressing the entire cDNA encoding prepro-EAP under the control of the galactose-inducible GRAP1 yeast promoter. Since three independent, site-directed mutations of EAP, including the substitution of an aspartyl catalytic residue, resulted in the intracellular accumulation of zymogen forms, we assumed that the EAP propeptide was autocatalytically processed. As a prerequisite to further improve the specificity of EAP, we therefore attempted to bypass this self-processing step in three different ways: 1) introduction of a Kex2-like recognition site between the pro and the mature part, 2) deletion of the prosequence (pre-EAP), and 3) co-expression in trans of the pre-EAP with its preprosequence. No improvement in the secretion of mutant enzymes was obtained in any of these experiments. As an alternative, we finally replaced the EAP processing site by the chymosin cleavage sequence of kappa-casein. Such a modification remained efficient in directing the secretion of active EAP only when a putative alpha-helix structural motif was conserved at the C terminus of the pro region.

Amino Acid Sequence↗
PubMed1995

Self-cloning in filamentous fungi: application to the construction of endothiapepsin overproducers in Cryphonectria parasitica.

The filamentous ascomycete fungus Cryphonectria parasitica naturally secretes endothiapepsin, an aspartic proteinase. It is cultured on a commercial scale as a source of the milk-clotting enzyme for cheese making. Our objective was to increase enzyme production of an industrial C. parasitica strain by a new technique of self-cloning; it consisted in the screening for transformants producing higher levels of endothiapepsin and having integrated only the DNA fragment of interest. Such genetically improved strains that are devoid of any foreign genes should be more readily acceptable for the production of food-grade enzymes.

Acetates↗
PubMed1995

[Clinical usefulness of biochemical markers of bone remodeling in osteoporosis].

Osteoporosis with its various clinical expressions is characterized by abnormalities of bone remodeling that can be assessed by biochemical markers of formation and resorption. Measurements of the serum concentration of osteocalcin and bone alkaline phosphatase (formation) and of the urinary excretion of pyridinoline and its peptides (resorption) are the most efficient markers in the investigation of osteoporosis. Recent studies, some of them still in progress, allow to define the clinical use of these markers: firstly to improve the evaluation of the fracture risk, and secondly to monitor the efficacy of antiresorptive drugs.

Biomarkers↗
PubMed1995

Choline blocks large conductance KCa channels in mammalian sympathetic neurones.

Using the outside-out configuration of the patch clamp technique, we examined the effects of externally applied choline chloride (ChCl) on the large-conductance calcium-dependent K+ (KCa) channel in sympathetic neurones of the rabbit coeliac ganglion. Isotonically replacing the bath sodium chloride by ChCl significantly decreased the unitary current amplitude of the KCa channels but did not affect their gating properties. The blocking effect was dose-dependent and required 24 mM ChCl to reach half-reduction of the KCa channel conductance (from 134 to 64 pS). In whole-cell voltage-clamped neurones, ChCl activated both nicotinic and muscarinic receptors, which induced various membrane current changes including Ca2+ current decrease. We therefore tested the effects of the cholinergic agonists acetylcholine and carbachol on excised KCa channels. Both agents failed to mimic the blocking effects of ChCl. We therefore conclude that KCa channels in sympathetic neurones are occluded by external choline chloride.

Animals↗
PubMed1994

Interleukin-4 inhibits bone resorption through an effect on osteoclasts and proinflammatory cytokines in an ex vivo model of bone resorption in rheumatoid arthritis.

OBJECTIVE: To assess local bone resorption in the context of rheumatoid synovitis and its modulation by interleukin-4 (IL-4). METHODS: We developed an ex vivo model of bone resorption using juxtaarticular samples of bone obtained during joint surgery. We studied the histomorphometric parameters of bone resorption and the regulation of the production of IL-6, leukemia inhibitory factor (LIF), and the collagen cross-link pyridinoline, which is released during bone resorption in vivo. RESULTS: This was a sensitive and dynamic model of bone resorption. The bone samples produced high levels of pyridinoline and as much cytokine as synovium pieces obtained from the same joint. IL-4 induced a 70% reduction of IL-6 and LIF production by bone pieces and reduced pyridinoline levels. Histomorphometric studies performed on bone samples indicated a 35% increase in the mean total bone area after 7 days of treatment with IL-4. More importantly, with IL-4, osteoclasts were not detectable in the bone sections. CONCLUSION: The inhibitory effect of IL-4 on bone resorption extends our knowledge of its antiinflammatory properties and suggests that the inflammatory cytokine imbalance in rheumatoid synovium also contributes to defects in bone resorption in RA.

Adult↗
PubMed1994

[Laparoschisis: a familial form].

BACKGROUND--Familial cases of gastroschisis are exceptional. CASE REPORT NO. 1--A boy was admitted at birth suffering from gastroschisis. Surgical repair was done but the patient died on day 24 with septicemia. CASE REPORT NO 2--Fifteen years later, gastroschisis was discovered by ultrasonography in a male fetus (GA = 26 weeks). Successful surgical repair was done just after the birth at a normal term. Mothers of both cases were sisters. CONCLUSIONS--The rare familial cases of gastroschisis have been seen in sibships. This is the first familial case seen in first cousins.

Abdominal Muscles↗
PubMed1993

Satellite glial cells in situ within mammalian prevertebral ganglia express K+ channels active at rest potential.

Patch-clamp experiments were performed on satellite glial cells wrapped around sympathetic neurons in the rabbit coeliac ganglion. With the cleaning method used, the glial cells could be kept in place and were directly accessible to the patch-clamp pipettes. Whole-cell recordings showed that glial cells had almost ohmic properties. Their resting potential (-79.1 +/- 1.2 mV) was found to be very nearly the same as the K+ reversal potential and approximately 20 mV more negative than that of the neurons they encapsulated. Unitary currents from ionic channels present in the glial membrane were recorded in the cell-attached configuration with pipettes filled with various amounts of K+, Na+ and gluconate. Only K(+)-selective channels with slight inwardly rectifying properties (in the presence of 150 mM [K+]o) were detected. These channels were active (Po = 0.7-0.8) at the cell resting potential. The channel conductance, but not its opening probability, was dependent on the [K+] in the pipette. Cl(-)-selective channels (outwardly rectifying and large conductance channels) were detected in excised patches. The properties of the K+ channels (increased inward current with [K+] and detectable outward current at low [K+]) are well suited for siphoning the K+ released by active neurons.

Animals↗
PubMed1993

[Antibiotic therapy of perforated appendicitis in children: comparison between the amoxicillin-clavulanic acid and the benzylpenicillin-netilmicin-metronidazole combinations].

In a multicentre trial we compared the clinical efficacy of amoxicillin/clavulanate used as a single-agent therapy with that of the three-agent combination usually prescribed in the post-operative period for appendicular peritonitis in children. Only bacteriologically documented peritoneal infections were included. Sixty-four patients were randomly distributed between two groups: Group A (29 cases) treated with amoxicillin/clavulanate, first administered iv (100 mg/kg/d), followed by conversion to the oral route (50 mg/kg/d) once the patient had been afebrile for 48 hours; Group B (35 cases) first treated by the iv route with benzylpenicillin (100,000 IU/kg/d) plus netilmicin (5 mg/kg/d) plus metronidazole (30 mg/kg/d), followed by conversion to the oral route for metronidazole (30 mg/kg/d). In both groups, the total duration of parenteral and oral treatment was not less than 5 days. One hundred and seventy nine bacterial strains were recovered from peritoneal fluid samples obtained during surgery; 86% of these were sensitive to amoxicillin/clavulanate. Clinical efficacy, assessed on the basis of time until return to normal temperature and gut transit and duration of hospitalization, was identical in both groups, with follow-up monitoring on day 30 showing recovery in all cases. Cure was obtained without any problems of infection in 25/29 patients in group A and in 34/35 patients in group B (non significant difference). Tolerance was excellent and identical in the two groups with the exception of three cases of thrombophlebitis which occurred in group B. The results of this study suggest that amoxicillin/clavulanate may be useful as single-agent therapy as a first-line curative treatment for appendicular peritonitis in children.

Adolescent↗
PubMed1992

Cloning and mutation of the gene encoding endothiapepsin from Cryphonectria parasitica.

Endothiapepsin is an aspartic protease secreted by Cryphonectria parasitica. It has a milk-clotting activity and is used in the cheese industry. The eapA gene encoding endothiapepsin has been cloned and sequenced. An open reading frame of 419 codons, which encodes a precursor differing from mature endothiapepsin by the presence of an 89 aa residue prepro-sequence, was found. The eapA gene is interrupted by three introns. C. parasitica mutant strains deficient in the production of endothiapepsin (eapA-) were constructed using a gene-replacement strategy. Two nonsense mutations were introduced at the beginning of the coding sequence by PCR-induced mutagenesis. The mutated DNA fragment was introduced in C. parasitica by co-transformation with a benomyl-resistant (benR) selection plasmid. Transformants which have the eapA- phenotype were obtained. Protein analysis confirmed that they secreted no detectable amount of endothiapepsin. No ectopic integration of the mutated eapA gene occurred in the eapA- transformants. Moreover, after one conidiation step, eapA- transformants yielded benomyl-sensitive (benS) segregants which were analyzed by Southern blotting experiments. The results revealed no difference with the wild-type strain, suggesting that the eapA-, benS segregants differed from the non-transformed strain only by the presence of the two nonsense mutations in the eapA locus.

Amino Acid Sequence↗
PubMed1992

Streptococcal toxic shock syndrome in children.

Two children with toxic shock-like syndrome due to streptococcal infection are reported. In both cases (one fatal) the site of infection was in the soft tissues. Both strains of group A hemolytic streptococci isolated from blood culture produced large amounts of erythrogenic toxin B (ET B) small amounts of ET C but no ET A. This report confirms the implication of Streptococcus pyogenes in toxic shock like syndromes. When ET A seems to be responsible for most cases observed in the USA, our cases and others observed in Europe could be related to strains producing large amounts of ET B.

Child↗