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S Leroy

Publications and source records attributed to S Leroy.

46 records · Page 3Linked to original sources
PubMed1994

Boc-Cys(Npys)-OH (BCNP): an appropriate reagent for the identification of T cell epitopes in cystine and/or cysteine-containing proteins.

Some T cell epitopes become inactive when their thiols are blocked with various irreversible reagents (Régnier-Vigouroux, 1988; Maillère, 1992; Maillère et al., 1993). Blocking protein and peptide thiols with BCNP (Boc-Cys(Npys)-OH) constitutes a most appropriate strategy when searching for thiol-containing T cell epitopes. Free cysteines can thus be readily transformed into disulphide-like moieties which not only resist undesirable oxidative reactions but which also remain susceptible to reduction by antigen presenting cells, a prerequisite for the activity of thiol-dependent T cell epitopes. We describe the use of this reagent in a study of the intact disulphide-rich protein, toxin alpha from Naja nigricollis, and also two disulphide-containing toxin fragments.

Amino Acid Sequence↗
PubMed1993

Role of thiols in the presentation of a snake toxin to murine T cells.

We isolated and characterized two T hybridomas specific for a highly stable snake toxic protein. One hybridoma, called T1C9, is I-E(d)-restricted and stimulated by both the native and reduced and carboxymethylated (RCM) toxins and by synthetic fragments containing the region 24-36. The other hybridoma, called T1B2, is I-A(d)-restricted and stimulated by the native toxin, only. Neither the RCM toxin nor any of the initial synthetic peptides used in our study could stimulate it. We show that this lack of effect is associated with the presence, in the epitope-containing fragment, of irreversible blocking groups on cysteine residues. Indeed, when the fragment 32-49 has its cysteines involved in either intra-(32-49SS) or mixed disulfides, a stimulation of T1B2 was observed. Fixed APC do not present native toxin to either hybridomas but present RCM toxin to T1C9. Strikingly, fixed APC present the peptide 32-49SS to T1B2; however, we show that this is possible only because the peptide disulfide is reduced. The thiol dependence of this epitope suggests that the native toxin can stimulate T1B2 only after disulfide reduction. This reaction may constitute a major step during the processing of the toxin and more generally of any disulfide-containing Ag.

Amino Acid Sequence↗
PubMed1993

Delayed response to radiofrequency ablation of accessory connections.

This article summarizes delayed interruption in anomalous conduction through accessory connections following radiofrequency ablation attempts in three patients. The time course of the delayed interruption in accessory connection conduction suggests that such an effect is unlikely to occur after the first week following unsuccessful radiofrequency ablation.

Adolescent↗
PubMed1989

[Resection and reconstruction of the carina with separate two-lung high-frequency jet ventilation].

Carinal resection and reconstruction via a right transpleural approach in an hypoxemic patient provides difficult maintenance of satisfactory gas exchange when one lung ventilation is inadequate. The present case report concerns a 62-year-old patient with chronic obstructive airways disease and a carinal squamous cell carcinoma. He underwent tracheobronchial reconstruction surgery by Barclay's procedure through a right postero-lateral thoracotomy. During resection and reconstruction phases, the gas exchange was maintained by a new technic: high-frequency-jet-ventilation (HFJV) with two small-bore catheters through the endotracheal tube and JVHF ventilators adjusted to the compliance of each lung (high for the right lung, low for the left one). No circulatory changes were observed during the sutures lines phase (90'). The oximeter and the arterial blood gas values show an adequate procedure. The immediate post operative period was unremarkable and uncomplicated. The histological diagnosis was squamous cell carcinoma involving the carina with one metastatic pretracheal lymph node and microscopic infiltration of the left main bronchus resection margin. Sixteen grays postoperative radiotherapy was required. Ten months after the patient is alive, without tumor recurrence. HFJV greatly facilitates surgery by avoiding endobronchial intubation with large cuffed tubes into the surgical field. In patients with low pulmonary reserve, bilateral lung HFJV is required: two JVHF ventilators with different ranges delivering separate ventilation to the right and left lungs avoid left hypoventilation and right surgical emphysema and insure good surgical conditions.

Anastomosis, Surgical↗
PubMed1988

[The child with deficient hearing. Medical, educational and sociological aspects].

The child's deafness is better known and better attended nowadays by different medical and chirurgical therapeutics, but also by the patient education of the teachers and parents who devoted themselves and devoted their lives towards the child,--shipwrecked in our world--whom although rescued manifests its own will to overcome the handicap and show itself as an entire human being. The parents' world of deaf children gathered into group with the aim of mutual assistance is scarcely known, even unknown to us. When you enter into it, you are taken by the devotion the assistance, the work, you take notice of the disarray, the sorrow and renew the hope and happiness. Yes, the happiness after a hard-earned victory.

Child↗
PubMedDate not supplied

(AAT)n repeat in the cannabinoid receptor gene (CNR1): association with cocaine addiction in an African-Caribbean population.

Owing to their agonist action on dopaminergic systems, cannabinoids may play a major role in substance dependency and schizophrenia. We examined the (AAT)n triplet repeat polymorphism nearby the CNR1 gene, which encodes human cannabinoid (CB1) receptor, in a male Afro-Caribbean population. The allelic and genotypic distributions were significantly different in non-schizophrenic cocaine dependents (n = 97), schizophrenic cocaine dependents (n = 45) and matched controls (n = 88) (P < 10(-4)). The frequency of the (AAT)12 repeat allele was increased in non-schizophrenic cocaine dependents and schizophrenic cocaine dependents vs controls (25.3 and 26.7 vs 5.7%) (P < 10(-4)). Our results support that the (AAT)n polymorphism nearby the CNR1 gene could be associated with predisposition to cocaine dependency.

Adult↗