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C Lapierre

Publications and source records attributed to C Lapierre.

26 records · Page 2Linked to original sources
PubMed1993

Characterization of histogranin receptors in human peripheral blood lymphocytes.

Histogranin (HN), a peptide recently isolated from bovine adrenal medulla, is also present in the spleen. In present studies, specific high affinity binding sites for HN were characterized on membrane preparations of human lymphocytes by radioligand binding. [125I]-[Ser1]HN binding was found to be dependent on time and protein concentration and to be sensitive to trypsin treatment. The binding displayed high affinity (Kd = 1.1 +/- 0.3 nM) and saturability (Bmax = 40.2 +/- 5.0 fmol/mg protein), and it was reversed upon addition of unlabelled [Ser1]HN and closely related peptides. The relative potency of various fragments in displacing [125I][Ser1]HN binding indicated that the active core of the molecule resides inside the C-terminal fragment, HN-(6-15). Interestingly, depressed patients displayed a marked decrease in the binding activity (from 15.4 to 8.55 fmol/mg protein at 0.5 nM of [125I][Ser1]HN). The presence of high affinity HN binding sites on lymphocytes provides evidence for a modulatory role for HN in the regulation of lymphocyte functions.

Adult↗
PubMed1993

Isolation and characterization of histogranin, a natural peptide with NMDA receptor antagonist activity.

Histogranin, was co-purified with bombesin-like immunoreactive peptides from bovine adrenal medulla. Its structure, H-Met-Asn-Tyr-Ala-Leu-Lys-Gly-Gln-Gly-Arg-Thr-Leu-Tyr-Gly-Phe-COOH, was determined by gas-phase Edman degradation. It was in accordance with its amino acid composition and corresponded to a 15 amino acid fragment (fragment 86-100) of histone H4 with substitutions in positions 1 (Val), 2 (Val) and 7 (Arg). The peptide was synthesized by the solid-phase procedure and the synthetic product was identical to the natural peptide as determined by its retention time on three analytical high-performance liquid chromatography systems. An antibody was raised against synthetic [Ser1]histogranin and used to monitor the presence of histogranin in various rat tissues and subcellular fractions of bovine adrenal medulla. In rats, immunoreactive histogranin was mainly concentrated in the pituitary (5065 pmol/g) and the adrenal glands (268 pmol/g), but it was also present in other tissues including the brain (1.6 pmol/g) and blood plasma (24 fmol/ml). A neuropeptide function for the adrenal peptide was suggested by its relative high concentration in chromaffin granules (42 fmol/mg protein as compared with 1 fmol/mg protein in cytosol) and its release from perfused bovine adrenal glands. In rat brain membrane preparations, synthetic histogranin displaced the binding of [3H]CGP 39653, a specific ligand of N-methyl-D-aspartate (NMDA) receptor. The displacement curve was biphasic with IC50 of 0.6 and 3955 nM, representing 33% and 67% of the binding sites, respectively. Intracerebroventricular (i.c.v.) injection of the peptide (5-100 nmol) in mice produced a dose-dependent protection against NMDA (0.5-1.0 nmol) -induced convulsions but not against (R,S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA, 0.25-2.0 nmol), kainate (0.25-0.75 nmol) and bicuculline (1-10 nmol)-induced convulsions. These results suggest that histogranin may be an endogenous modulator of NMDA receptor functions.

2-Amino-5-phosphonovalerate↗
PubMed1991

Dynorphin A-(1-13)-Tyr14-Leu15-Phe16-Asn17-Gly18-Pro19 : a potent and selective kappa opioid peptide.

Dynorphin A-(1-13)-Tyr14-Leu15-Phe16-Asn17-Gly18-Pro19+ ++ (dynorphin Ia: a peptide derived from the structure of adrenal dynorphin I) was synthesized by the solid-phase procedure. The product was purified and compared with dynorphin A-(1-13) and [D-Pro10]dynorphin A-(1-11) for its ability to inhibit the electrically evoked contractions of the guinea pig ileum (GPI) and mouse vas deferens (MVD) and to compete with the binding of [3H]ethylketocyclazocine (kappa ligand), [3H][D-Ala2,MePhe4,Glyol5]enkephalin (mu ligand) and [3H][D-Ser2,Thr6]Leu-enkephalin (delta ligand) to membrane preparations of the guinea pig cerebellum or rat brain. Additionally, the antinociceptive effects of the synthetic peptide were assessed in rat paw-pressure and tail-flick tests. In the GPI, dynorphin Ia possessed a relative potency (IC50 0.5 nM) that was comparable to that of [D-Pro10]dynorphin A-(1-11) (IC50 0.5 nM) or dynorphin A-(1-13) (IC50 0.7 nM). In the delta specific MVD assay, dynorphin Ia displayed a reduced potency (IC50 235 nM) as compared with that of dynorphin A-(1-13) (IC50 20 nM) or [D-Pro10]dynorphin A-(1-11) (IC50 46 nM). The affinity of dynorphin Ia for the kappa site in the guinea pig cerebellum (Ki 0.25 nM) was comparable to those of dynorphin A-(1-13) (Ki 0.11 nM) and [D-Pro10]dynorphin A-(1-11) (Ki 0.10 nM). However, the peptide possessed reduced affinities for the mu (Ki 6.7 nM) and delta (Ki 71 nM) opioid receptors as compared with [D-Pro10]dynorphin A-(1-11) (Ki 1.7 and 1.5 nM) an dynorphin A-(1-13) (Ki 0.5 and 4.4 nM, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMedDate not supplied

Soft-tissue venous malformations in adult patients: imaging and therapeutic issues.

Venous malformations are the most common vascular malformations. However, confusion with respect to terminology and imaging guidelines continues to result in improper diagnosis and treatment. An appropriate classification scheme for vascular anomalies is important to avoid the use of false generic terms. Adequate imaging in association with clinical findings is crucial to establishing the correct diagnosis. Doppler ultrasonography should be the initial imaging modality and demonstrates absence of flow or low-velocity venous flow. Computed tomography and magnetic resonance (MR) imaging are used primarily for pretreatment evaluation of lesion extension. These lesions are usually hypointense on T1-weighted MR images and markedly hyperintense on T2-weighted images with variable gadolinium enhancement. Direct phlebography helps confirm the diagnosis and exclude other soft-tissue tumors. Three distinct phlebographic patterns (cavitary, spongy, dysmorphic) have been identified. In most cases, conservative treatment is recommended. Sclerotherapy with or without surgery is useful in cases of functional impairment or significant aesthetic prejudice, even if recurrences are frequent. Direct phlebography is performed when a more detailed assessment of the vascular pattern is needed or as part of sclerotherapy. Use of the appropriate imaging technique is critical in establishing the diagnosis, evaluating extension, and planning appropriate treatment.

Arteriovenous Malformations↗