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Biomedical subjects

S Pelletier

Publications and source records attributed to S Pelletier.

At least 37 records · Page 2Linked to original sources
PubMed1994

Antiphospholipid syndrome as the second cause of non-tumorous Budd-Chiari syndrome.

In a prospective study of 22 patients with non-tumorous Budd-Chiari syndrome, four were found to have the antiphospholipid syndrome with no other cause of hepatic vein thrombosis. All four patients were young women. The antiphospholipid syndrome was secondary to systemic lupus in one case, to a "lupus-like disease" in another, and apparently primary in the remaining two cases. Two patients died. The other two are in good health on chronic oral anticoagulation. In our experience, the antiphospholipid syndrome is a frequent cause, after myeloproliferative disorders, of non-tumorous Budd-Chiari syndrome. In such patients, long-term anticoagulation may prevent recurrence or extension of thrombosis.

Adolescent↗
PubMed1992

[Pancreatic endocrine tumor with metastases and increase of alpha-fetoprotein. A case report].

The authors report the case of a 48 years old man presenting a pancreatic islet cell carcinoma (gastrinoma) with liver, nodes and peritoneal metastases, associated with an elevated alpha-fetoprotein (AFP) concentration. Incomplete remission was first obtained with a chemotherapy using Streptozotocin combined with 5-Fluorouracil, in association with a Somatostatin analogue (SMS 201-995). But when relapses occur, another chemotherapy was not so effective. Serum gastrin and AFP levels had the same evolution and appear to have the same interest to follow the course of the disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

[Temporal arteritis in young subjects. A trial of nosological classification apropos of 6 cases].

Six young-adult patients (19- to 32-years-old) are described: 3 men with temporally localized systemic vasculitis (thromboangiitis obliterans 2, Churg-Strauss angiitis 1) and 3 patients (2 men, 1 woman) with isolated temporal arteritis. Temporal arteritis in subjects under 40 years of age consists of either a temporal localization of systemic vasculitis (thromboangiitis obliterans or Buerger's disease, Churg-Strauss angiitis or polyarteritis nodosa) or a distinct entity of which only 12 biopsy-proven cases have been reported to date. The latter is differentiated from temporal (giant cell) arteritis of the older patient by a higher incidence in men, and the absence or rarity of general symptoms, ocular complications and an accelerated erythrocyte sedimentation rate. Two types of temporal arteritides in young adults seem to be distinguishable: an asymptomatic form with an isolated temporal nodule and a more symptomatic one. In some cases, temporal arteritis in young adults corresponds to a unique entity "juvenile temporal arteritis", which seems to be different from Takayasu's arteritis, localized forms of polyarteritis nodosa and Kimura's disease. Although its treatment remains difficult to define, therapy of the symptomatic form could include steroids, whereas the asymptomatic one seems to require only simple monitoring.

Adult↗
PubMed1991

Mechanism of proton pumping in bacteriorhodopsin by solid-state NMR: the protonation state of tyrosine in the light-adapted and M states.

Solid-state 13C NMR spectra were employed to characterize the protonation state of tyrosine in the light-adapted (bR568) and M states of bacteriorhodopsin (bR). Difference spectra (isotopically labeled bR minus natural-abundance bR) were obtained for [4'-13C]Tyr-labeled bR, regenerated with [14-13C]retinal as an internal marker to identify the photocycle states. The [14-13C]retinal has distinct chemical shifts for bR555, for bR568, and for the M intermediate generated and thermally trapped at pH 10 in the presence of 0.3 M KCl or 0.5 M guanidine. Previous work has demonstrated that tyrosine and tyrosinate are easily distinguished on the basis of the chemical shift of the 4'-13C label and that both NMR signals are detectable in dark-adapted bR, although the tyrosinate signal is only present at pH values greater than 12. In the present work, we show that neither the light-adapted form of bR prepared at pH 7 or 10 nor the M state thermally trapped at -80 degrees C in 0.3 M KCl pH 10, or in 0.5 M guanidine pH 10, shows any detectable tyrosinate. In addition, after the M samples were briefly warmed (approximately 30 s), no tyrosinate was observed. However, small (1-2 ppm) changes in the structure or dispersion in the Tyr peak were observed in the M state phototrapped by either method. These changes were reversible when the sample was warmed, although on a time scale slower than the relaxation of the retinal back to the bR568 conformer.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteriorhodopsins↗
PubMed1991

Phase II trial of copper zinc superoxide dismutase (CuZn SOD) in the treatment of Crohn's disease.

Bovine Cu Zn SOD was used during an 8 year period as an antiinflammatory drug in 26 patients with severe Crohn's disease (CDAI 300) usually after failure of corticotherapy or when this drug was discontinued because of side effects or infection. This was a phase II trial during which doses routes of administration and concomitant therapies were progressively modified. We obtained 73% good short term responses (judged upon CDAI and anatomic healing) and 82% positive results on long term evolution (the criteria were: i CDAI lower than 100 in between relapses, ii complete healing or notable improvement of lesions, iii no surgery needed, iv return to work. The acceptability was excellent with the free enzyme. Since the above described experience, published in Free Radical Biology and Medicine (1989, 7: 145-151), we used always the same treatment schedule (SOD 8 mg/day associated with Desferroxamine--500 mg subcutaneous every 2 days). The follow-up during the 87-89 period showed that 12 are in good health without any relapse, 9 experienced one or more relapses, and showed good responses upon resumption of treatment, 5 failed to respond to treatment, all part of the initial group on which SOD treatment had already failed, and among whom 3 were lost for follow-up before 1987, and two others took up another SOD treatment which also failed. 3 new patients (2 females, 1 male) were treated since then, and all 3 had positive results (one with disappearance of ileocoecal mass). The efficacy of SOD as an antiinflammatory drug in Crohn's disease needs to be confirmed by controlled trials.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1990

Brain natriuretic peptide binding sites in rats: in vitro autoradiographic study.

Brain natriuretic peptide (BNP) is a recently discovered family of natriuretic peptides highly homologous to atrial natriuretic factor (ANF). Quantitative in vitro autoradiography with a computerized microdensitometer demonstrated that the distribution of BNP binding sites is similar to the known distribution pattern of ANF binding sites in rat tissues. Analysis of saturation and competition curves disclosed that the maximal binding capacity for BNP-(Asp-81--Tyr-106) and ANF-(Ser-99--Tyr-126) is similar within the plexiform layer of the olfactory bulb, the choroid plexus, and the adrenal zona glomerulosa. Examination of the competition curves of BNP-(Asp-81--Tyr-106), ANF-(Ser-99--Tyr-126), and des-(Gln-116--Gly-120)ANF-(Asp-102--Cys-121)NH2 (C-ANF, a ligand highly specific for ANF-R2 receptors) for 125I-labeled BNP-(Asp-81--Tyr-106) and 125I-labeled ANF-(Ser-99--Tyr-126) binding revealed that ANF fully displaced 125I-BNP binding and, conversely, BNP completely displaced 125I-ANF binding in these tissues, whereas C-ANF partially displaced 125-BNP and 125-ANF binding. Angiotensin II, insulin, glucagon, and substance P had no influence on 125I-BNP binding in the above tissues. These results support the view that BNP and ANF share the same binding sites in rats.

Animals↗
PubMed1990

Localization and characterization of binding sites for circulating and cerebroventricular atrial natriuretic factor in rat choroid plexus.

In vitro autoradiographic studies showed that high-affinity atrial natriuretic factor (ANF) binding sites are present on rat choroid plexus (Kd = 83.8 pM, Bmax = 22.9 fmol/mg protein). Guanylate cyclase-coupled receptors (ANF-R1) represent 30% and non-guanylate cyclase-coupled ANF receptors (ANF-R2) represent 70% of the total ANF receptors present in this tissue. To provide detailed cellular localization of the binding sites, the technique of electron-microscopic autoradiography was applied using 125I-ANF (Ser 99-Tyr 126) as an in vivo ligand. In order to identify possible binding sites at the basolateral and the apical aspects of the choroid plexus, the ligand was injected into the carotid artery or into the lateral cerebral ventricles, respectively. Light-microscopic autoradiography demonstrated that ANF binds specifically to choroid plexus regardless of its route of administration. Electron-microscopic autoradiography showed that silver grains were localized primarily on epithelial cells of the choroid plexus (96-99%) and marginally on endothelial and pial cells. In choroidal epithelial cells, ultrastructural analysis of silver grain distribution revealed that, at 2 min after intracarotid or intracerebroventricular 125I-ANF injection, lysosomes were the most distinctly labeled organelle (highest relative specific radioactivity). HPLC Chromatographic analysis disclosed that 96-99% of choroid plexus-bound ANF was already degraded 2 min after injection and that at least 63-66% of the degradation took place at the plasma membrane. These results indicate that ANF binding sites are present on both aspects of choroidal epithelium, and suggest that ANF is very quickly degraded in choroid plexus by membrane-associated as well as lysosome-associated processes.

Animals↗
PubMed1989

Phase II trial of copper zinc superoxide dismutase (CuZnSOD) in treatment of Crohn's disease.

Bovine CuZnSOD was used during an 8-year period as an anti-inflammatory drug in 26 patients with severe Crohn's disease, usually after failure of corticotherapy, or when this drug was avoided because of side-effects or abscesses. This was a Phase II trial during which doses, routes of administration and concomitant therapies were progressively modified. The acceptability was excellent with the free enzyme. We obtained 19/26 very good short term responses, and 82% good results on long term evolution. The efficacy of SOD as an anti-inflammatory drug in Crohn's disease needs to be confirmed by controlled trials.

Adolescent↗
PubMed1988

[Prolonged delta antigen in the blood without occurrence of anti-delta antibodies in 2 immunosuppressed patients].

Delta coinfection or superinfection in a patient with chronic hepatitis B is characterized by a very transient delta antigenemia and an early seroconversion of IgM to IgG anti-delta. The persistent expression of delta antigen in the liver can be associated with acute, severe, or chronic hepatitis. In our two patients, delta antigenemia persisted respectively 10 weeks and 14 months with aggravation of liver histopathologic lesions without seroconversion. Such a serologic profile during delta infection does not seem to have been reported previously. These two cases concerned two patients with an important immunosuppression, one by a major immunosuppressive therapy and HIV superinfection, the other by an acquired immunodeficiency syndrome. The cytotoxic effect of delta virus in such circumstances is discussed.

Acquired Immunodeficiency Syndrome↗