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Biomedical subjects

G Faure

Publications and source records attributed to G Faure.

At least 55 records · Page 3Linked to original sources
PubMed1994

The origin of the diversity of crotoxin isoforms in the venom of Crotalus durissus terrificus.

Crotoxin, the main toxin from the venom of the South American rattlesnake Crotalus durissus terrificus, is a beta-neurotoxin which consists of the non-covalent association of two subunits: a phospholipase A2 subunit B (CB), and a non-enzymic subunit A (CA). We have previously purified and characterized several isoforms of each subunit of crotoxin in the venom collected from numerous snakes. Furthermore, three cDNAs encoding two CB isoforms and the precursor, pro-CA, of subunit A have been isolated from a cDNA library prepared from a single venom gland of Crotalus durissus terrificus. The aim of this study is to analyse an individual snake venom from an animal that has been used to construct a cDNA library. Several isoforms of subunit A and two isoforms of subunit B were isolated and compared to purified and characterized subunit isoforms from pooled venom. The result of this study showed that the multiplicity and the diversity of crotoxin isoforms result from post-translational modifications occurring on a precursor and from the expression of different messenger RNAs present in an individual snake. It allowed for the identification of the two CB isoforms encoding cDNAs expressed in the individual venom with two isoforms from pooled venom, CBc and probably CBa2, that belong to two classes of crotoxin complexes which can be distinguished biochemically and pharmacologically.

Amino Acid Sequence↗
PubMed1994

Antipeptide antibodies directed to the C-terminal part of ammodytoxin A react with the PLA2 subunit of crotoxin and neutralize its pharmacological activity.

Crotoxin and ammodytoxin A are snake venom neurotoxic phospholipases A2. Polyclonal antibodies against three synthetic peptides selected from the C-terminal part of the primary structure of ammodytoxin A were tested by ELISA for their interaction with crotoxin and its subunits, CA and CB. All three antipeptide antibodies reacted specifically with corresponding parts of ammodytoxin A and CB, either native or reduced. Conversely, polyclonal antibodies produced against ammodytoxin A and CB reacted strongly with all three peptides, suggesting that they constitute at least a part of natural epitopes in both proteins. All antipeptide antibodies reacted also with the corresponding peptides derived from CB by cyanogen bromide cleavage. The biological activity of the immune complexes was tested. No significant change in the enzymatic activity of CB, ammodytoxin A or crotoxin was observed with any of the three antipeptide antibodies. These antibodies were, however, able to protect mice against the lethal potency of CB and to prolong survival time of mice injected with crotoxin. These antipeptide antibodies were assayed in vitro for their protective effect against the action of CB or crotoxin on synaptosomes from Torpedo marmorata electric organ. They partly inhibited the acetylcholine release induced by both proteins. These results indicate that the C-terminal part of CB is likely to be involved in the pharmacological action of crotoxin.

Amino Acid Sequence↗
PubMed1994

Microparticle-enhanced nephelometric immunoassay of anti-thyroid peroxidase autoantibodies in thyroid disorders.

Crude thyroid peroxidase extracted from human thyroid microsomes was covalently bound onto polyacrylic and polyfunctional copolymerized microparticles. We observed agglutination of the thyroid peroxidase-microparticle conjugate with 13 monoclonal antibodies (mAbs) specific for epitopes on four different antigenic domains of human thyroid peroxidase (TPO; EC 1.11.1.7), after addition of anti-mouse immunoglobulins. We quantified agglutination by measuring with a specially designed nephelometer the light scattered by the conjugates. This allowed us to develop a microparticle-enhanced nephelometric immunoassay for human anti-TPO autoantibodies (aAbs) with defined epitopic specificity, based on the ability of aAbs to inhibit mAb-induced agglutination. Applied to patients with autoimmune thyroid diseases, this assay confirmed the polyclonality of anti-TPO aAbs and their preferential reactivity toward epitopes located on the A and B antigenic domains of the TPO molecule. The same specificities seem to be present in patients with Hashimoto thyroiditis or Graves disease.

Autoantibodies↗
PubMed1994

Migraine treatment by oral magnesium intake and correction of the irritation of buccofacial and cervical muscles as a side effect of mandibular imbalance.

A previous paper showed a significant decrease in average erythrocyte magnesium level in 79 migraine patients as compared to 55 controls. This paper completes the results of the initial evaluation, with 152 migraine cases and 85 controls. Serum and erythrocyte magnesium determinations show the following results. Mean serum magnesium was 0.82 mmol/litre in migraine patients and 0.85 mmol/litre in controls, P < 0.005. Mean erythrocyte magnesium was 2.04 mmol/litre in migraine patients and 2.32 mmol/litre in controls, P < 0.0005. These results confirm those of the first paper, but show a more significant difference between the means of the two groups for serum magnesium, which was not significant for the lower number of people involved in the previous study. In all migraine cases without exception clinical evaluation showed an abnormal sensitivity of the buccofacial and cervical muscles which was unilateral and homolateral when migraine was unilateral; it was bilateral when migraine was bilateral. The muscles which were the most sensitive to palpation were the sternocleidomastoid, external pterygoid and scalene. These findings show that migraine patients have a magnesium deficit, which, while not constant, is a frequent occurrence. This raises the problem of the relationship between migraine and other disorders characterized by magnesium deficit, such as latent tetany, mitral valve prolapse, and certain allergies. This magnesium deficit probably promotes muscle irritability, especially when a local imbalance factor results in a permanent pathological stimulation. In addition to irritation and hypersensitivity, migraine attacks occur, particularly after stress, digestive, endocrine and neurological problems.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1993

Comparison of crotoxin isoforms reveals that stability of the complex plays a major role in its pharmacological action.

Crotoxin from the venom of the South American rattlesnake Crotalus durissus terrificus is a potent neurotoxin consisting of a weakly toxic phospholipase-A2 subunit (CB) and a non-enzymic, non-toxic subunit (CA). Crotoxin complex (CACB) dissociates upon interaction with membranes: CB binds while CA does not. Moreover, CA enhances the toxicity of CB by preventing its non-specific adsorption. Several crotoxin isoforms have been identified. Multiple variants of each subunit give different crotoxin complexes that can be subdivided into two classes: those of high toxicity and low enzymic activity and those of moderate toxicity and a high phospholipase-A2 activity. In this study, we demonstrate that the more-toxic isoforms block neuromuscular transmission of chick biventer cervicis preparations more efficiently than weakly toxic isoforms. The less-toxic crotoxin complexes have the same Km and Vmax as CB alone. In contrast, the more-toxic isoforms are enzymically less active than CB. These differences correlate with the stability of the complexes: less-toxic isoforms are less stable (Kd = 25 nM) and dissociate rapidly (half-life about 1 min), whereas the more-toxic isoforms are more stable (Kd = 4.5 nM) and dissociate more slowly (half-life 10-20 min). The rate of interaction of crotoxin complexes with vesicles of negatively charged phospholipids paralleled the rate of dissociation of the complexes in the absence of vesicles. The differences of pharmacological and biochemical properties of crotoxin isoforms indicate that the stability of crotoxin complexes plays a major role in the synergistic action of crotoxin subunits: a stronger association between the two crotoxin subunits would account for their slower dissociation rate, a weaker enzymic activity, a slower interaction with phosphatidylglycerol vesicles, a faster blockade of neuromuscular transmission and a higher lethal potency.

Animals↗
PubMed1993

Flow and image cytometry for DNA analysis in bladder washings: improved concordance by using internal reference for flow.

Using flow or image cytometry, we compared the DNA distribution of cells from bladder washings from 52 patients with bladder cancer. For image cytometry, urothelial nuclei (recognized visually) were analyzed for DNA content using polymorphonuclear nuclei as internal diploid reference. For flow cytometry, two methods can be used: either all cells can be analyzed, as commonly performed, or urothelial cells can be analyzed alone, after specific detection. In this flow cytometry study, cells were doubly stained for panurothelial antigens T16 and for DNA. All the cells were first analyzed using peripheral lymphocytes as an external reference; 79% of the results were similar with results obtained from image analysis. For discordant results, flow-cytometric data were reprocessed to identify immunologically stained urothelial cells; one additional case became concordant with image cytometry when only urothelial cells were analyzed, with lymphocytes as diploid reference; a better concordance (94%) was found when the nonurothelial cells of the samples served as a diploid reference instead of peripheral lymphocytes. This suggests that we achieved an improvement of the flow-cytometric evaluations for ploidy assessment, and we conclude that, on these conditions, flow or image analysis can be considered as equivalent methods for DNA content studies of tumors.

Adult↗
PubMed1993

Early effects of short-time cigarette smoking on the human lung: a study of bronchoalveolar lavage fluids.

We investigated the early effects of cigarette smoking in healthy subjects by means of lung lavage, looking at markers of alveolar permeability, the alveolar cell profile, the immunophenotyping of macrophages and lymphocytes, and the level and profile of surfactant phospholipids. Bronchoalveolar lavages (BAL) were performed in 33 healthy subjects [20 nonsmokers (nS), 13 moderate and short-time smokers (S)]. In the acellular supernatants we measured the markers of alveolar permeability (i.e., total proteins, albumin, albumin/urea), the alveolar epithelial lining fluid (AELF), the surfactant amounts and profile, and explored the blood lymphocytes by in vitro exposure. The cell pellet established the alveolar formula and a membrane mapping of macrophages (LFA-1 and HLA-DRII expression) and lymphocytes (CD4, CD8, LFA-1, HLA-DRII expression). We found no significant increase of alveolar permeability in our smokers, but an increased alveolar cellularity (more than 3-fold vs nS, P < 0.05) evenly distributed between sub-populations except for an enhanced number of eosinophils in smokers (P < 0.05 vs nS). Smokers' alveolar macrophages had an overloaded cytoplasm, a decreased percentage of antigen-handling cell expression (HLA DRII: P < 0.05 vs nS) and a low percentage of cell to cell adhesion molecule expression (LFA-1: P < 0.05 vs nS). Smoking history and LFA-1 expression on alveolar macrophages were interrelated. Smokers' alveolar lymphocyte subsets were more often T suppressor cells (CD8+) and had an increased percentage of antigen-presenting cell expression (HLA DRII: P < 0.05 vs nS). Smokers' BAL fluid did not show the inhibitory control of phytohemagglutinin-induced lymphocyte proliferation present in nonsmokers' fluids. Surfactant phospholipid amounts were similar, but phosphatidylethanolamine was raised and the ratio of phosphatidylcholine to sphingomyelin decreased in smokers (P < 0.05 vs nS). We observed specific cellular and biochemical alterations in the lung lavage of short-time smokers. Alveolar macrophage and lymphocyte expression of LFA-1 and HLA-DR II molecules was altered. Smokers' alveolar fluids lost the physiologic regulatory control of T mitogen-induced lymphocyte proliferation. Membrane phospholipids released by cellular damage increased early in tobacco-exposed lung fluids. This profile of alterations may be an early and sensitive marker of smoking-induced lung damage.

Adult↗
PubMed1992

[Reconstruction of the penile skin in Fourier's gangrene: the use of a helical skin graft].

The emergency treatment of Fournier's and perineal gangrene is now well defined and is based on excision of the necrotic tissues and broad spectrum antibiotics combined with hyperbarid oxygen therapy and symptomatic resuscitation measures. However, several procedures have been described for the reconstruction of the excised zones. In the light of one case of Fournier's gangrene, the authors evaluate reconstruction of the penile skin by means of a helical split-skin graft. With a follow-up of one year, the morphological and functional result was excellent. The patient has normal erection and the suture line does not contain any retractile adhesions. The authors therefore consider that this simple, but little known procedure should be part of the urologist's therapeutic arsenal for reconstruction of the penile skin.

Gangrene↗
PubMed1992

Surface markers in adult acute myeloblastic leukemia: correlation of CD19+, CD34+ and CD14+/DR--phenotypes with shorter survival. Groupe d'Etude Immunologique des Leucémies (GEIL).

The immunophenotype of blast cells was investigated in a multicentric study of 154 adult acute myeloblastic leukemias (AMLs). A panel of 27 monoclonal antibodies (MoAbs) was tested in indirect immunofluorescence. Expression of CD14 (UCHM1), CD19 (SB4), CD36 (OKM5), and HLA-DR were associated with higher mean leucocyte counts. CD14 expression correlated with low hemoglobin level and the absence of CD33 (MY9) with low platelet counts. Extramedullary disease was associated with CD16 (Leu11b) and HLA-DR antigen positivity. The study of relationships between surface markers and FAB criteria confirmed the predominant expression of CD14 in the M5 sub-group (p less than 0.000001) and the association of CD19 and CD36 with monocytic M4/M5 subgroups (respectively p less than 0.00002 and p less than 0.000001). All patients received an induction therapy including an anthracycline and cytarabine. The median follow-up was 13 months. The achievement of complete remission (CR) was inversely correlated with CD34 (B13C5) and CD19 expression: CR was obtained in 31 of 59 (53%) CD34-positive AML versus 64 of 75 (85%) CD34-negative cases (p less than 0.0001) and 11 of 24 (46%) CD19-positive versus 95 of 122 (78%) CD19-negative cases (p less than 0.01). In univariate analysis, a longer survival was associated with CD33 expression and the combined phenotypes CD36+/CD19- and CD16+/CD14-. Conversely, the CD18(IOT18)+/CDw65(VIM2)- phenotype was related to shorter survival. The expression of CD19, of CD34, and of the combined phenotype CD14+/DR--correlated with shorter survival as demonstrated both in univariate and multivariate analysis (p less than 0.03 in each case in multivariate analysis).

Antigens, CD↗
PubMed1992

NARES: a model of inflammation caused by activated eosinophils?

Twenty patients were selected on the basis of perennial rhinitis, the absence of allergy and with an eosinophil count higher than 20% of total leucocytes in nasal secretions (NARES). Nasal endoscopy with biopsies from the middle turbinate and sinus CT were performed. Biopsies were processed for histological examination and for immunofluorescence. The clinical progress during treatment was scrutinized. An acute congestive aspect of the nasal mucosa was noted in 4 cases, and micropolyposis in 9 cases. Sinus CT showed opacity of the ethmoidal cells in 87% of cases (maxillary sinuses: 75%; frontal sinus: 46%; sphenoidal sinus: 31%). An eosinophilic infiltrate of the nasal mucosa was constituted in 9 cases: In 6 cases, the cells expressed the Fc epsilon RII receptor, recognized by the monoclonal antibody Bb10. Anti-H1 drugs usually failed to result in a clinical improvement and local eosinophilia was not changed. Local corticoids were more effective but not sufficient in some cases, so that oral corticotherapy was needed. Ethmoidectomy was performed in three cases. NARES seems to evolve in three stages: (1) migration of eosinophils from the vessels to the secretions; (2) retention of eosinophils in the mucosa which might be linked to activation of unknown origin; (3) nasal polyposis. Numerous interactions between irritation of the epithelium, release of substance P, and eosinophils, lead to the hypothesis of a neurogenic origin of NARES.

Adult↗
PubMed1991

Multiplicity of acidic subunit isoforms of crotoxin, the phospholipase A2 neurotoxin from Crotalus durissus terrificus venom, results from posttranslational modifications.

Crotoxin, the major toxin of the venom of the South American rattlesnake, Crotalus durissus terrificus, is made of two subunits: component B, a basic and weakly toxic phospholipase A2, and component A, an acidic and nontoxic protein that enhances the lethal potency of component B. Crotoxin is a mixture of isoforms that results from the association of several isoforms of its two subunits. In the present investigation, we have purified four component A isoforms that, when associated with the same purified component B isoform, produced different crotoxin isoforms, all having the same specific enzymatic activity and the same lethal potency. We further determined by Edman degradation the polypeptide sequences of these four component A isoforms. They are made of three disulfide-linked polypeptide chains (alpha, beta, and gamma) that correspond to three different regions of a phospholipase A2 precursor. We observed that the polypeptide sequences of the various component A isoforms all agree with the sequence of an unique precursor. The differences between the isoforms result first by differences in the length of the various chains alpha and beta, indicating that component A isoforms are generated from the proteolytic cleavage of the component A precursor at very close sites, possibly by the combined actions of endopeptidases and exopeptidases, and second by the possible cyclization of the alpha-NH2 of the N-terminal glutamine residue of chains beta and gamma. These observations indicate that the component A isoforms are the consequence of different posttranslational events occurring on an unique precursor, rather than the expression of different genes.

Amino Acid Sequence↗
PubMed1991

Antiovary antibodies, repeated attempts, and outcome of in vitro fertilization.

OBJECTIVE: To determine whether the microtrauma induced by repeated puncture of ovarian follicles could result in the production of autoantibodies in women submitted to in vitro fertilization (IVF). DESIGN: Antiovarian antibodies were assayed in serum samples obtained from women engaged in IVF and in serum samples from healthy controls. SETTING: Blood samples were obtained after oocyte collection in the local hospital's IVF unit. PATIENTS: One hundred ten women undergoing IVF entered the study. Oocyte division, numbers of embryos, and pregnancy were recorded for each woman. Control samples were from 40 individuals with no sign of autoimmune disorder. INTERVENTIONS: Antiovarian antibodies were assayed in indirect immunofluorescence and enzyme-linked immunosorbent assay (ELISA) using human ovary as antigen. Specific immunoglobulin (Ig)G, IgA, and IgM were tested separately in an ELISA. MAIN OUTCOME MEASURE: Antiovarian antibody levels were compared between patients and controls and correlated with the subsequent results of IVF. RESULTS: Significantly higher levels of IgG, IgA, and IgM antiovarian antibodies were observed in the group of IVF women (P less than 0.001). IgM antiovarian antibodies correlated with a lower number of embryos (P less than 0.001) and IVF failure (P less than 0.05). CONCLUSIONS: These data suggest that ovarian trauma may lead to the production of autoantibodies.

Adult↗
PubMed1991

Dynamic changes in soluble interleukin-2 receptor levels during treatment of Graves' disease. Correlation with disease activity.

The activation of T lymphocyte is accompanied by the release of soluble interleukin-2 receptors (sIL-2R) which can be assessed in biological fluids. A prospective study of the dynamic changes in sIL-2R levels was performed in the serum of 10 patients undergoing a medical treatment for Graves' disease. All patients received carbimazole during the study and, when necessary, L-thyroxine to compensate hypothyroidism. sIL-2R levels were measured before (M0) and after the 1st (M1), 3rd (M3) and 6th month (M6) of treatment. The levels of sIL-2R were high at M0 and M1, and decreased significantly between M1 and M3 (p = 0.03). At M0, the levels of sIL-2R were highly correlated with triiodothyronine (T3) levels (p = 0.0003), early [131I] uptake (p = 0.007) and, to a lesser degree, with anti-thyrotropin receptor antibody levels (p = 0.02). At M6, no correlation was found anymore. We conclude that sIL-2R levels are increased in patients with untreated Graves' disease. They are highly correlated with the markers of Graves' disease activity and decrease during medical treatment.

Adult↗