Biomedical subjects

S Moreau

Publications and source records attributed to S Moreau.

At least 19 recordsLinked to original sources

PubMed2003

[Otogenic cavernous sinus thrombophlebitis. A case report].

OBJECTIVES: Acquire knowledge concerning the diagnosis and treatment of otogenic cavernous sinus thrombophlebitis. PATIENT AND METHODS: We report a case of otogenic cavernous sinus thrombophlebitis (CST) in a 6-year-old boy. RESULTS: CST diagnosis was based on clinical signs (septic illness, ocular nerve palsy and chemosis), and neuro-imaging confirmed the diagnosis. Contrast-enhanced CT scan demonstrates different signs: (i) filling defect or heterogeneous enhancement of cavernous sinus, (ii) cavernous sinus enlargement with bulging of the lateral wall, (iii) intensive enhancement of lateral wall corresponding to enhancement of a collateral network replacing the thrombosed cavernous veins, (iiii) and sometimes indirect orbital signs (exophthalmus, densification of the retro-orbital fat, superior ophthalmic dilatation with partial or no enhancement in case of thrombosis extension). The bacteria most frequently found are Streptococci, Streptococcus pneumoniae, Staphylococcus aureus, Gram-negative rods and anaerobes combined. The therapeutic management of CST consists of intravenous administration of appropriate antibiotics combined radical mastoidectomy if medical therapy has failed. Anticoagulant therapy is controversial. CONCLUSION: Knowledge of early diagnosis of otogenic cavernous sinus is important because prior to the antibiotic era, CST was almost always fatal. Currently, therapeutic outcome is not always favorable due to high morbidity after aggressive treatment.

Cavernous Sinus Thrombosis↗

PubMed2002

[Bronchial foreign bodies in children].

BACKGROUND: Tracheobronchial aspiration of foreign bodies in children is a rare event that can be serious. We report a 10-year retrospective study of tracheobronchial foreign body aspiration in children. METHOD: This retrospective analysis involved 87 patients who underwent endoscopy at the ENT unit of the Caen University Hospital. RESULTS: Foreign bodies were found in 34 of the 87 patients. Average age was 3 years, with a male predominance. Peanuts were the most common foreign bodies observed (16/34). Most of the foreign bodies were removed via the right main bronchus (17/34). Clinical and radiological signs depended on delay to admission and were found to be normal in 15% and 37.5% of the cases respectively. Twenty-four children out of 34 had a positive history of foreign body inhalation. All foreign bodies were removed during the endoscopy procedure. CONCLUSION: This work underlines the much-debated function of chest x-ray, the need for a rigorous technically correct endoscopy procedure and the importance of close cooperation between the anesthesiologist and the endoscopist.

Bronchi↗

PubMed2002

[Chondromas and low-grade chondrosarcomas of the larynx: a case report].

OBJECTIVE: We report a case of cricoid chondroma, underlining the difficulty in establishing a precise differential diagnosis between chondroma and low-grade chondrosarcoma of the larynx. MATERIAL AND METHODS: A 48-year-old woman developed inspiratory dyspnea. The final diagnosis was cricoid chondroma. We reviewed our case and data in the literature on these cartilaginous tumors. RESULTS: The patient was treated with conservative surgery. At 18 months follow-up, no recurrence has been detected. DISCUSSION: These tumors are rarely found in an ENT location and have similar histological features. According to many authors, the clinical course alone enables a distinction between chondroma and low-grade chondrosarcoma. Surgical treatment is indicated and provides good phonatory function in the vast majority of the cases.

Chondroma↗

PubMed2002

[Utility and limitations of speech audiometry testing in the detection of occupational noise-induced hearing loss: a comparative study in two groups in the hospital setting].

OBJECTIVE: The objective of this study is the evaluation of the calculation of 100% intelligibility threshold and noise resistance index as a monitoring test in populations exposed to noise in their work environment. METHOD: This is a retrospective exposed-unexposed study as the exposure to the risk factors took place before the survey. The exposed subjects were chosen in principle on sonometric criteria and the unexposed subjects among employees whom we believe were not exposed. The exploration method included history taking, clinical examination, free field audiometry and speech audiometry with background noise. RESULTS: The exposed population has a 100% intelligibility threshold on average equal to 29.69 dB, significantly higher than in the unexposed population where it is calculated at 25.30 dB (p = 0.07). The noise resistance index varies with age (p = 0.04). CONCLUSION: Our study shows the existence of a significant hearing difference between two populations with different noise exposure. It demonstrates a relationship between a hearing loss risk factor such as noise and the occurrence of the "professional hearing loss" disorder. The calculation of the 100% intelligibility index and the noise resistance index advantageously complements tonal audiometry. These procedures provide a better approach to the social impact of hearing loss but were not useful in the detection of hearing loss.

Adult↗

PubMed2001

Low-temperature sterilization using gas plasmas: a review of the experiments and an analysis of the inactivation mechanisms.

Utilizing an ionized gas (plasma) to achieve sterilization is an alternative to conventional sterilization means as far as sterilization of heat-sensitive materials and innocuity of sterilizing agents are concerned. The literature on plasma sterilization is reviewed. A major issue of plasma sterilization is the respective roles of UV photons and reactive species such as atomic and radicals. Insight into this matter is obtained by analyzing the survival curves of microorganisms. In contrast to classical sterilization where such plots show a unique straight line, plasma sterilization yields survival diagrams with two or three different linear segments. Three basic mechanisms are involved in the plasma inactivation of microorganisms: (A) direct destruction by UV irradiation of the genetic material of microorganisms; (B) erosion of the microorganisms atom by atom, through intrinsic photodesorption by UV irradiation to form volatile compounds combining atoms intrinsic to the microorganisms; (C) erosion of the microorganisms, atom by atom, through etching to form volatile compounds as a result of slow combustion using oxygen atoms or radicals emanating from the plasma. In some cases, etching is further activated by UV photons, increasing the elimination rate of microorganisms. These mechanisms make plasma sterilization totally different from classical sterilization techniques and suggest its use to inactivate nonconventional infectious agents such as the abnormal prions.

Bacillus subtilis↗

PubMed2001

Modulation of RNA function by oligonucleotides recognizing RNA structure.

Numerous RNA structures are responsible for regulatory processes either because they constitute a signal, like the hairpins or pseudoknots involved in ribosomal frameshifting, or because they are binding sites for proteins such as the trans-activating responsive RNA element of the human immunodeficiency virus whose binding to the viral protein Tat and cellular proteins allows full-length transcription of the retroviral genome. Selective ligands able to bind with high affinity to such RNA motifs may serve as tools for dissecting the molecular mechanisms in which they are involved. Such ligands might also constitute prototypes of therapeutic agents when RNA structures play a role in the expression of dysfunctional genes or in the multiplication of pathogens. Different classes of ligands (aminoglycosides, interacalating agents, peptides) are of interest to this aim. However, oligonucleotides deserve particular consideration. They have been extensively used in the frame of the antisense strategy. The apparent simplicity of this rational approach is, at first sight, very attractive. Indeed, numerous successful studies have been published describing the efficient inhibition of translation, splicing, or reverse transcription in cell-free systems, in cultured cells, or in vivo by oligomers complementary to an RNA region. However, RNA structures restrict the access of the target site to the antisense sequence: The competition between the intramolecular association of RNA regions weakens or even abolishes the antisense effect. Various possibilities have been developed to circumvent this limitation. This includes both rational and combinatorial strategies. High-affinity oligomers were designed to invade the RNA structure. Alternatively, triplex-forming oligonucleotides (TFO) and aptamers may recognize the folded RNA motif. Whereas the use of TFOs is rather limited owing to the strong sequence constraints for triple-helix formation, in vitro selection offers a way to explore vast oligoribo or oligodeoxyribo libraries to identify strong, selective oligonucleotide binders. The candidates (aptamers) selected against the TAR RNA element of HIV-1, which form stable loop-loop (kissing) complexes with the target, provide interesting examples of oligonucleotides recognizing a functional RNA structure through an important contribution of tertiary interactions.

Animals↗

PubMed2001

The use of pigs as an animal model to evaluate the efficacy, potency and specificity of two growth hormone releasing factor analogues.

In 1982, Guillemin et al reported the isolation of the human (h) growth hormone (GH) releasing factor (GRF) from a pancreatic tumour in an acromegalic patient. Since then, work to develop potent GRF analogues has been widespread and the rat has been the main animal model used. The aim of the present study was to compare the efficacy, potency and specificity of two GRF analogues with those of the native GRF(1-29)NH(2)using pig (p) as the animal model. Two analogues, Al ([His(1), D-Ala(2), Ala(8,9,15,17), D-Arg(29)] hGRF(1-29)NH(2)) and A2 ([D-Ala(2), Ala(8,9,15,17), D-Arg(29)] hGRF(1-29)NH(2)) were compared with the h or pGRF(1-29)NH(2). Five studies were designed using 28-48 kg BW growing barrows. Results showed that the two GRF analogues were more potent than the native GRF molecule, were highly specific, were active for long periods of time and were able to induce changes in body composition similar to those reported with GH or other GRF analogues. Because of the similarity between swine and human species with respect to the amino acid sequence of GRF and to the physiology, secretion and effects of GH, it can be proposed that the pig could be used as a pre-clinical animal model to study and test new GRF molecules over short and long periods of time.

Animals↗

PubMed2001

Inhibition of HIV-1 replication in vitro and in human infected cells by modified antisense oligonucleotides targeting the tRNALys3/RNA initiation complex.

The untranslated 5' leader region of the human immunodeficiency virus type 1 (HIV-1) RNA plays an essential role in retroviral replication. It is the first retrotranscribed RNA region, primed from a cellular tRNALys3 partially annealed to the HIV-1 primer binding site (PBS). The structural and functional features of the HIV-1 reverse transcription initiation complex have been thoroughly studied. In this work, we used chemically modified antisense oligonucleotides (AS-ODN) as competitors of the natural tRNALys3 primer for the PBS region. Modified 2'-O-methyl AS-ODN were able to inhibit in vitro HIV-1 reverse transcription and displace the tRNALys3 previously annealed to the PBS. The destabilization of the initiation complex by 2'-O-methyl ODN was a sequence-specific process. We further demonstrated the importance of an anchor region contiguous to the PBS in the annealing of the antisense molecule, allowing the displacement of tRNALys3. The 20-mer 2'-O-methyl molecules were also able to inhibit viral replication in HIV-1-human infected cells, either by blocking cDNA synthesis during the early phase or by interfering with the annealing of the tRNALys3 primer to the PBS during the late phase of the viral cycle. Thus, the highly conserved retroviral initiation complex was shown to be a promising target when using the antisense strategy.

Base Sequence↗

PubMed2001

Overlapping functions of the Saccharomyces cerevisiae Mre11, Exo1 and Rad27 nucleases in DNA metabolism.

MRE11 functions in several aspects of DNA metabolism, including meiotic recombination, double-strand break repair, and telomere maintenance. Although the purified protein exhibits 3' to 5' exonuclease and endonuclease activities in vitro, Mre11 is implicated in the 5' to 3' resection of duplex ends in vivo. The mre11-H125N mutation, which eliminates the nuclease activities of Mre11, causes an accumulation of unprocessed double-strand breaks (DSBs) in meiosis, but no defect in processing HO-induced DSBs in mitotic cells, suggesting the existence of redundant activities. Mutation of EXO1, which encodes a 5' to 3' exonuclease, was found to increase the ionizing radiation sensitivity of both mre11Delta and mre11-H125N strains, but the exo1 mre11-H125N strain showed normal kinetics of mating-type switching and was more radiation resistant than the mre11Delta strain. This suggests that other nucleases can compensate for loss of the Exo1 and Mre11 nucleases, but not of the Mre11-Rad50-Xrs2 complex. Deletion of RAD27, which encodes a flap endonuclease, causes inviability in mre11 strains. When mre11-H125N was combined with the leaky rad27-6, the double mutants were viable and no more gamma-ray sensitive than the mre11-H125N strain. This suggests that the double mutant defect is unlikely to be due to defective DSB processing.

Alleles↗

PubMed2001

Trauma and extended separation from family among Latin American and African refugees in Montreal.

Although the vast majority of refugees have suffered trauma and extended separation from their families in exile, little is known about the interactions between these two types of experience. The qualitative and quantitative analyses of data gathered from 113 refugees from Latin America and Africa suggest that the joint occurrence of trauma and separation has a significant impact on emotional distress and confirm that the family plays a key role as an anchor of emotion and identity.

Adult↗

PubMed2001

[Arterial anatomy of the facial nerve at the stylo-mastoid foramen].

OBJECTIVE: To provide specific informations about the arterial related anatomy of the trunk of the facial nerve from the stylomastoid foramen to its bifurcation. METHODS: Dissection of 30 facial nerves in fresh cadavers after arterial casting with red-colored latex. RESULTS: A great anatomic variability does exist. The facial nerve is most often in relation to the stylomastoid artery which arises from the posterior auricular artery. The stylomastoid artery originates sometimes from the occipital artery or from the external carotid artery. In 19 cases of 30 the stylomastoid artery passes medially to the nerve, and 11 cases laterally. CONCLUSION: During parotid surgery, the main trunk of the facial nerve may be difficult to identify because of a large-caliber stylomastoid artery which can mask it. Therefore it is preferable to dissect this artery with caution, remaining at distance from the dangerous.

Arteries↗

PubMed2001

[Intracranial complications of acute mastoiditis].

We report a case of extradural abscess after acute mastoiditis in an 8-years-old boy. The clinic diagnostic of an intracranial complication is difficult. The most common present symptoms are fever, otalgia and otorrhea but are not specific. Neurologic symptoms are suggestive signs of an intracranial complication. We believe that, in acute mastoiditis performance of a CT scan of the brain and temporal bones with intravenous contrast, contribues to the diagnostic of intracranial complication. The diagnostic of thrombosis sinus sigmoid is evoked with slight contrast enhanced sinus sigmoid and failure to opacify. The characterisation of an epidural empyema is a hypodense epidural collection in a contrast-enhanced CT scan. The most common isolated organism are Streptococcus Pneumoniae, Staphylococcus aureus and Pseudomonas aeuginosa. The therapeutic management includes combination of intraveinous antibiotics, mastoidectomy and surgery of the intracranial complication.

Acute Disease↗

PubMed2001

[Parathyroid cysts].

Two cases of parathyroid cysts are described. One cyst was symptomatic, the other was discovered while performing thyroidectomy. In both cases, the cysts were non-functional. There have been reports of functional cysts occurring in a lesser proportion and causing primary hyperthyroidism. These benign cysts are rare (300 cases reported in the literature). Surgery is the treatment of choice in most cases.

Adult↗

PubMed2000

Alteration of gene conversion tract length and associated crossing over during plasmid gap repair in nuclease-deficient strains of Saccharomyces cerevisiae.

A plasmid gap repair assay was used to assess the role of three known nucleases, Exo1, Mre11 and Rad1, in the processing of DNA ends and resolution of recombination intermediates during double-strand gap repair. In this assay, alterations in end processing or branch migration are reflected by the frequency of co-conversion of a chromosomal marker 200 bp from the gap. Gap repair associated with crossing over results in integration at the homologous chromosomal locus, whereas the plasmid remains episomal for non-crossover repair events. In mre11 strains, the frequency of gap repair was reduced 3- to 10-fold and conversion tracts were shorter than in the wild-type strain, consistent with a role for this nuclease in processing double-strand breaks. However, conversion tracts were longer in a strain containing the nuclease deficient allele, mre11-H125N, suggesting increased end processing by redundant nucleases. The frequency of gap repair was reduced 2-fold in rad1 mutants and crossing over was reduced, consistent with a role for Rad1 in cleaving recombination intermediates. The frequency of gap repair was increased in exo1 mutants with a significant increase in crossing over. In exo1 mre11 double mutants gap repair was reduced to below the mre11 single mutant level.

Crossing Over, Genetic↗

PubMed2000

4-amino-1H-benzo[g]quinazoline-2-one: a fluorescent analog of cytosine to probe protonation sites in triplex forming oligonucleotides.

We developed a new fluorescent analog of cytosine, the 4-amino-1H-benzo[g]quinazoline-2-one, which constitute a probe sensitive to pH. The 2'-O-Me ribonucleoside derivative of this heterocycle was synthesized and exhibited a fluorescence emission centered at 456 nm, characterized by four major excitation maxima (250, 300, 320 and 370 nm) and a fluorescence quantum yield of Phi = 0.62 at pH 7.1. The fluorescence emission maximum shifted from 456 to 492 nm when pH was decreased from 7.1 to 2.1. The pK(a) (4) was close to that of cytosine (4.17). When introduced in triplex forming oligonucleotides this new nucleoside can be used to reveal the protonation state of triplets in triple-stranded structures. Complex formation was detected by a significant quenching of fluorescence emission (approximately 88%) and the N-3 protonation of the quinazoline ring by a shift of the emission maximum from 485 to 465 nm. Using this probe we unambiguously showed that triplex formation of the pyrimidine motif does not require the protonation of all 4-amino-2-one pyrimidine rings.

Base Sequence↗

PubMed2000

DNA triplex stabilization property of natural anthocyanins.

The DNA triplex stabilization property of seven natural anthocyanins (five monoglucosides and two diglucosides) has been measured by the mean of triplex thermal denaturation experiments. We have noticed a difference between the diglucosides that do not modify this melting temperature and the monoglucosides (namely 3-O-beta-D-glucopyranoside of malvidin, peonidin, delphinidin, petunidin and cyanidin) which present a weak but significant stabilizing effect. It appears clearly that the difference between the two series could be due to the supplementary sugar moiety at the 5 position for the diglucosylated compounds, that would make them too crowded to allow interaction with the triplex. Among the monoglucoside series, the most active compounds are the only ones to embody a catechol B-ring in their structure that could be important for such an interaction. The need to have pure and fully characterized compounds to run these measurements, made it possible for us to unambiguously assign the 1H and 13C NMR spectra with the help of 2D NMR experiments. Thus, missing data of compounds not totally described earlier, are provided herein.

Anthocyanins↗

PubMed2000

[Obstructive sleep apnea syndrome and hypertrophic tonsils in infants].

BACKGROUND: Even if failure to thrive in infants suffering from obstructive sleep apnea syndrome (OSAS) due to hypertrophic tonsils is well documented in the literature, the surgical act is often delayed due to the lack of diagnostic evidence. CASE REPORTS: We report three cases which share the common characteristic of age of onset, tonsillar hypertrophy, growth retardation and growth catch-up after tonsillectomy. Authors emphasize the importance of clinical diagnosis as a sufficient tool in making the decision of surgery, thus avoiding unnecessary and expensive investigations. CONCLUSION: The diagnosis of OSAS in infants and children is essentially clinical, depending mainly on a history provided by the parents, laying stress on nocturnal symptoms and clinical examination. Growth retardation is frequent in this syndrome and should be systematically sought. Tonsillectomy, which is effective in relieving respiratory manifestations, also allows growth recovery.

Age of Onset↗

PubMed2000

Facial nerve: vascular-related anatomy at the stylomastoid foramen.

We dissected 30 facial nerves in fresh cadavers after arterial casting with red latex to provide specific information about the arterial-related anatomy of the trunk of the facial nerve from the stylomastoid foramen to its bifurcation. We found that a wide anatomic variability does exist. The trunk of the facial nerve was in proximity to the stylomastoid artery, which originated from the posterior auricular artery in 70% of the specimens (21/30), from the occipital artery in 20% (6/30), and directly from the external carotid artery in 10% (3/30). The stylomastoid artery passed medially to the trunk of the facial nerve in 63 of the specimens (19/30) and laterally in 37% (11/30). Among these 11 specimens, 8 were large-caliber stylomastoid arteries. During parotid surgery, the main trunk of the facial nerve may be difficult to identify, because a large-caliber stylomastoid artery can mask it. Therefore, it is important to dissect this artery with caution.

Facial Nerve↗