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D Reynaud

Publications and source records attributed to D Reynaud.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Endoscopic treatment of subcutaneous fat necrosis secondary to pancreatic-vascular fistula: apropos of a case].

PATIENT AND METHOD: We report the case of a 68-year-old man who presented a pancreatic tumor with a pancreato-vascular fistula and a Weber-Christian syndrome. Pancreatic enzymes levels at the admission were high: amylasemia 2,470 IU/L (N < 110) and lipasemia 11,700 IU/L (N < 220). The treatment consisted in total parenteral nutrition and somatostatin (100 micrograms x 3/day). Because we noted neither clinical nor biological improvement after 10 days of treatment, we performed an endoscopic retrograde pancreatography. During this examination, we put a 7 French diameter prosthesis through the Wirsung stenosis. RESULTS: No problem arose after endoscopy: since the day after the endoscopy, pancreatic enzymes decreased by half and become normal in 4 days; arthralgias and cutaneous injuries, both caused by cytosteatonecrosis, disappeared respectively in 5 and 10 days. There is no evidence of subsequent recurrence after 3 months of follow-up. CONCLUSION: Pancreatic endoscopic prosthesis can replace the surgical treatment of pancreato-vascular fistula with a good efficacy.

Aged↗
PubMed1998

[Infectious endocarditis on permanent endocavitary stimulation leads: apropos of 2 cases].

BACKGROUND: Permanent endocavitary pacemaker lead infectious endocarditis is rare. Two new cases are reported. CASE REPORTS: The first case appeared in a 63-year-old white woman with a permanent endocavitary pacemaker for 3 years. It was caused by Streptococcus bovis, unique to this pathology. The second case was caused by Streptococcus epidermidis in a diabetic 72-year-old woman. In these two cases, the clues to the diagnosis were hemocultures and transesophageal echocardiography. CONCLUSION: These two cases emphasize the importance of transesophageal echocardiography (TEE) for diagnosis and for driving treatment. Treatment is based on appropriate antibiotics and pacemaker removal. In the second, case, the material was surgically removed under cardiopulmonary bypass because of the size of the infection.

Aged↗
PubMed1997

Hepoxilin A3 is oxidized by human neutrophils into its omega-hydroxy metabolite by an activity independent of LTB4 omega-hydroxylase.

Hepoxilin A3-methyl ester is taken up by intact human neutrophils where it is first hydrolyzed into the free acid which is subsequently converted into a single major metabolite. The structure of this metabolite was determined through mass spectral analysis of several derivatives, and through identity with an authentic compound prepared by chemical synthesis. The metabolite was identified as omega-hydroxy-hepoxilin A3 showing that the epoxide functionality of the parent hepoxilin is not opened during incubation with human neutrophils. All attempts to investigate hepoxilin metabolism in broken cells, despite the presence of protease inhibitors (Aproteinin, PMSF, DFP) and supplementation with NADPH were unsuccessful. Metabolism of hepoxilin A3 required the intact cell, while parallel experiments with LTB4 as substrate demonstrated that this eicosanoid was metabolized into its omega-hydroxy metabolite regardless of whether intact or broken cell preparations were used provided that NADPH was present in the latter. Hepoxilin metabolism in intact cells was inhibited dose-dependently by CCCP (0.01-100 microM), a mitochondrial uncoupler, whereas LTB4 metabolism was unaffected by CCCP. This data suggests that metabolism of hepoxilin A3 occurs in intact human neutrophils through omega-oxidation, is likely located in the mitochondrial compartment of the cell (inhibition by CCCP) and is carried out by an activity that is independent of the well characterized, relatively stable microsomal LTB4 omega-hydroxylase.

8,11,14-Eicosatrienoic Acid↗
PubMed1997

Docosahexaenoic acid causes accumulation of free arachidonic acid in rat pineal gland and hippocampus to form hepoxilins from both substrates.

Hepoxilins (Hx) are biologically active metabolites of arachidonic acid (AA) formed regioselectively from 12(S)-HPETE by 'hepoxilin synthase'. Hx modulate synaptic neurotransmission in hippocampal CA1 neurons, and inhibit norepinephrine release in hippocampal slices. During the course of our studies we investigated whether docosahexaenoic acid (DHA) was a substrate for hepoxilin formation. We used two tissues, the pineal gland and hippocampal slices. Tissues were incubated alone or with AA (20 microg/ml) or DHA (20 microg/ml). After 60 min at 37 degrees C, samples were acid-extracted to convert Hx into their stable trioxilin (TrX) form and analyzed as the Me-TMSi derivatives by EI-GC/MS to determine the structures of the DHA metabolites, and as PFB-TMSi derivatives by GC/MS in the NICI mode using SIM to simultaneously quantify TrX products of the 3-series (derived from AA) monitored at m/z 569, while those of the 5-series (derived from DHA) were monitored at m/z 593. Results show good conversion of both substrate fatty acids by the rat pineal gland and hippocampal slices, into the 3-series (21.3 +/- 5.8 and 12.5 +/- 2.2 ng/microg protein, respectively) and 5-series TrX (12.3 +/- 2.7 and 2.9 +/- 0.4 ng/microg protein, respectively). Surprisingly though, experiments with DHA, in both tissues, also showed formation of TrX derived from endogenous AA (3-series) (10.4 +/- 8.3 and 3.1 +/- 2.1 ng/microg protein, respectively). These experiments demonstrate previously unreported actions of DHA causing the accumulation of AA, which is converted into hepoxilins. In order to prove that AA is accumulated during DHA stimulation of the tissue, we carried out separate experiments with hippocampal slices in which the neutral lipids and phospholipids were labeled with [14C]AA. DHA caused a time-dependent appearance of free [14C]AA which was released mostly from the TG pool. Measurement of the AA/DHA ratio in the TG pool by GC/MS further indicated that DHA is incorporated into the TG at the expense of AA. These results demonstrate that DHA competes with AA for acylation into the metabolically active TG fraction, and both fatty acids are converted into hepoxilins of the corresponding series.

8,11,14-Eicosatrienoic Acid↗
PubMed1997

Hepoxilin-evoked intracellular reorganization of calcium in human neutrophils: a confocal microscopy study.

Hepoxilin A3 has previously been shown to cause a rapid dose-dependent rise in intracellular calcium in intact human neutrophils in suspension. Two components have been observed, an initial rapid phase of intracellular calcium rise, followed by a slow decline to plateau levels that remain above the original baseline calcium levels. These changes have been suggested to involve the release of calcium from intracellular stores in the ER (initial rapid phase), while the slower rate of decline (plateau phase) was presumed to be due to calcium influx as it was abolished in zero calcium extracellular medium. The present study used confocal microscopy to examine the response to hepoxilin A3 at the subcellular level. Our results show that calcium dynamics in response to hepoxilin A3 varies in different subcellular compartments within the cell and that hepoxilin A3 evoked a persistent accumulation of calcium in organelles. The hepoxilin-evoked calcium sequestration was eliminated by prior exposure to CCCP, a mitochondrial uncoupler. CCCP also eliminated the plateau phase of the calcium response in cell suspension, suggesting that this phase was due to mitochondrial accumulation of calcium rather than calcium influx. Experiments with DiI-loaded cells, a membrane marker, showed that the nuclear calcium was not elevated by hepoxilin addition to the cells. These results demonstrate that hepoxilins evoke the release of calcium from the ER which is taken up by the mitochondria where it is tightly sequestered. These results offer an explanation of observations previously made with cell suspensions in which hepoxilin A3 was shown to inhibit the calcium mobilizing effects of chemotactic agents.

8,11,14-Eicosatrienoic Acid↗
PubMed1997

12-HETE and 12-HPETE potently stimulate intracellular release of calcium in intact human neutrophils.

We describe here the effects of two 12-lipoxygenase products, 12-HETE (12-hydroxyeicosa (5Z,8Z,10E,14Z) tetraenoic acid) and 12-HPETE (12-hydroperoxyeicosa (5Z,8Z,10E,14Z) tetraenoic acid), on the release of intracellular calcium in intact human neutrophils using the INDO-1 AM fluorescent dye technique. Both products dose dependently stimulate intracellular release, with 12-HETE being more powerful than 12-HPETE. The threshold concentration for 12-HETE was 5 ng/ml (1.5 x 10-8 M), while that for 12-HPETE was 10 ng/ml. The (12S) regioisomer was slightly more active than the (12R) isomer. The laser potency of 12-HPETE may be due to its conversion into the less active hepoxilins as incubation of neutrophils with (12S/R)-HPETE in a nonradioactive assay, using fluorescent ADAM esters of the products, generated mostly hepoxilin A3 (8-hydroxy-(11S,12S) epoxyeicosa (5Z,9E,14Z)trienoic acid), indicative of an enzymatic process. In contrast, boiled neutrophil preparations converted 12-HPETE primarily into hepoxilin B3 which previously showed to be derived nonenzymatically. This data demonstrates that 12-HETE, known to be generated in significant amounts by platelets, can act transcellularly to modify intracellular concentrations of calcium in neutrophils. This may in turn affect the responsiveness of these cells to other chemotactic factors.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1996

Hepoxilin A3-specific binding in human neutrophils.

Hepoxilins have been shown to release calcium from intracellular stores in human neutrophils [Dho, Grinstein, Corey, Su and Pace-Asciak (1990) Biochem. J. 266, 63-68; Laneuville, Reynaud, Grinstein, Nigam and Pace-Asciak (1993) Biochem. J. 295, 393-397]. In this paper we report that tritium-labelled hepoxilin A3 (8S) binds to broken neutrophil membranes in a time-, substrate- and temperature-dependent fashion. Specific binding was displaced with unlabelled hepoxilin A3. Specific binding was greatest at 37 degrees C. Competitive binding was best observed with unlabelled hepoxilin A3 (8S); the glutathione conjugate, HxA3-C (8S or 8R), or 12(S)-hydroxyeicosatetraenoic acid was less active. Similarly inactive in displacing the bound radiolabelled hepoxilin A3 was leukotriene B4 as well as a variety of prostaglandins and thromboxane B2. Formylmethionyl-leucylphenylalanine was similarly inactive in competing for the hepoxilin binding sites. Specific binding was inhibited by pretreatment of the broken membranes during 30 min at 37 degrees C with proteinase K, while specific binding of the intact cells was unaffected. Scatchard analysis of binding data revealed a single population of binding sites with apparent KD and Bmax. of 79.3 +/- 9.1 nM and 8.86 +/- 1.4 pmol/ml per 2 x 10(6) cells (+/- S.E.M.) respectively reflecting approx. 2.67 x 10(6) sites/cell. These results demonstrate for the first time that neutrophils contain specific binding sites to hepoxilin A3.

8,11,14-Eicosatrienoic Acid↗
PubMed1996

Chemical synthesis and actions of 11,12-thiirano-hepoxilin A3.

A novel analog of hepoxilin A3 has been chemically synthesized in which the 11,12-epoxide group has been altered to a thiirano group. This has been accomplished through allylic rearrangement of unnatural (11 R, 12 R)-hepoxilin B3 under Mitsunobu conditions, first into unnatural (11 R, 12 R)-hepoxilin A3, followed by conversion of this compound with inversion of the epoxide centers into the thiirano-hepoxilin A3 having the natural 11 S, 12 S configuration. We also report herein evidence showing that thiirano-hepoxilin A3 raises intracellular calcium concentrations in intact human neutrophils.

8,11,14-Eicosatrienoic Acid↗
PubMed1995

High-performance liquid chromatographic separation of fluorescent esters of hepoxilin enantiomers on a chiral stationary phase.

Fluorescent anthryl (ADAM) derivatives of hepoxilins have been shown to possess good chromatographic properties affording good sensitivity for the high-performance liquid chromatographic analysis and detection of these compounds and related eicosanoids (12-hydroxyeicosatetraenoic acid) in biological samples. We report herein the separation of all possible stereoisomers of hepoxilins A3 and B3 as their methyl esters as well as their ADAM ester and acetate derivatives on a cellulose trisdimethyphenylcarbamate chiral stationary phase (Chiracel OD) in the normal-phase mode. This methodology is important to address the mechanistic route of biosynthesis of these products.

8,11,14-Eicosatrienoic Acid↗