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Biomedical subjects

M Rey

Publications and source records attributed to M Rey.

At least 37 records · Page 2Linked to original sources
PubMed2000

A Tensorial Formalism Adapted to the Rovibronic Couplings in the Colored Hexafluorides: Application to the nu(5)(F(2g)) and nu(3)(F(1u)) Modes.

A tensorial formalism adapted to the case of transition-metal hexafluorides in a degenerate electronic state has been developed on the basis of preceding works about spherical-top molecules in a nondegenerate electronic state. We have introduced electronic operators constructed using group theory features and some physical considerations. Vibronic couplings (Jahn-Teller effect, etc.) have been reviewed for the triply degenerate vibrational modes nu(5)(F(2g)) and nu(3)(F(1u)) leading to the identification of the main vibronic parameters. For the first time, an effective rovibronic Hamiltonian as well as the effective transition moment operators (dipole moment and polarizability) for rovibronic transitions have been studied qualitatively thanks to the tensorial algebra properties. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Aneurysm of the anterior leaflet of the mitral valve secondary to aortic valve endocarditis.

Aneurysm of the anterior mitral leaflet is a rare complication of infective aortic valve endocarditis, the natural evolution of which is generally its rupture, with subsequent acute and severe mitral regurgitation. Its presence cannot be recognized with transthoracic echocardiography and even in surgery. We describe a 78-year-old man with aortic valve endocarditis, in whom transesophageal echocardiography was essential for the diagnosis of this complication, its therapeutic management, and the postoperative follow-up after simple valve repair. In addition, the most appropriate surgical approach is discussed.

Aged↗
PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗
PubMed2000

[Improvement of Trichoderma strains for biocontrol].

The use of the fungal genus Trichoderma to control fungal plant diseases is a promising alternative to the use of chemical compounds. The aim of this work has been to obtain Trichoderma strains with improved capacity as biological control agents. To do so, the hydrolytic capacity on fungal cell walls of strains of the fungus Trichoderma harzianum has been increased. On one hand, transformation experiments with genes which coded for chitinases and glucanases have been carried out in T. harzianumstra ins. On the other hand, the medium composition has also been modified in order to eliminate proteolytic degradation of some of the overproduced enzymes. Finally, hybrid chitinolytic enzymes with substrate-binding domains have been produced as an alternative to obtain improved biocontrol strains. The transformant strains, when compared with the wild type, showed improved antifungal capacity against the phytopathogenic fungus Rhizoctonia solani, in in vitro experiments.

English Abstract↗
PubMed1999

Involvement of phosphatidylinositol 3-kinase in stromal cell-derived factor-1 alpha-induced lymphocyte polarization and chemotaxis.

The role of phosphatidylinositol 3-kinase (PI3-kinase), an important enzyme involved in signal transduction events, has been studied in the polarization and chemotaxis of lymphocytes induced by the chemokine stromal cell-derived factor-1 alpha (SDF-1 alpha). This chemokine was able to directly activate p85/p110 PI3-kinase in whole human PBL and to induce the association of PI3-kinase to the SDF-1 alpha receptor, CXCR4, in a pertussis toxin-sensitive manner. Two unrelated chemical inhibitors of PI3-kinase, wortmannin and Ly294002, prevented ICAM-3 and ERM protein moesin polarization as well as the chemotaxis of PBL in response to SDF-1 alpha. However, they did not interfere with the reorganization of either tubulin or the actin cytoskeleton. Moreover, the transient expression of a dominant negative form of the PI3-kinase 85-kDa regulatory subunit in the constitutively polarized Peer T cell line inhibited ICAM-3 polarization and markedly reduced SDF-1 alpha-induced chemotaxis. Conversely, overexpression of a constitutively activated mutant of the PI3-kinase 110-kDa catalytic subunit in the round-shaped PM-1 T cell line induced ICAM-3 polarization. These results underline the role of PI3-kinase in the regulation of lymphocyte polarization and motility and indicate that PI3-kinase plays a selective role in the regulation of adhesion and ERM proteins redistribution in the plasma membrane of lymphocytes.

Antigens, CD↗
PubMed1999

Determination of sodium and ammonium ions in disproportionate concentration ratios by ion chromatography.

In ion chromatography, samples of very different ammonium-to-sodium concentration ratios are difficult to quantify since these two cations have similar selectivities for stationary phases containing commonly used sulfonate or carboxylate cation-exchange functional groups. The IonPac CS15 cation-exchange column, with carboxylate and phosphonate functional groups as well as a crown ether group, was developed to address this limitation. Selectivity for the common inorganic cations on this column is different from that of conventional cation-exchange columns in that the separation between sodium and ammonium ions has been greatly increased, allowing for determinations of low levels of one in the presence of high levels of the other with an isocratic eluent. For larger than 4000:1 sodium-to-ammonium concentration ratios, an eluent step change or gradient elution is needed. For moderate ratios, combinations of this column with a carboxylate column, containing no crown ether group, can be used at room temperature with an isocratic eluent containing no organic solvent.

Amines↗
PubMed1999

Sufentanil, fentanyl, and alfentanil in head trauma patients: a study on cerebral hemodynamics.

OBJECTIVES: To determine the effects of bolus injection and infusion of sufentanil, alfentanil, and fentanyl on cerebral hemodynamics and electroencephalogram activity in patients with increased intracranial pressure (ICP) after severe head trauma. DESIGN: Randomized, unblended, crossover study. SETTING: Intensive care unit and trauma center in a university hospital. PATIENTS: Six patients with head trauma and ICP monitoring, sedated at the time of the study with propofol infusion and full neuromuscular blockade. INTERVENTIONS: Following a randomized order, in an unblended and crossover fashion, the level of sedation was deepened with a 6-min injection of either sufentanil (1 microg/kg), alfentanil (100 microg/kg), or fentanyl (10 microg/kg) followed by an infusion of 0.005, 0.7, and 0.075 microg/kg/min, respectively, for 1 hr. The three opioids were given to each patient at 24-hr intervals. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure (MAP), ICP, cerebral perfusion pressure (CPP), and jugular vein bulb oxygen saturation (Svjo2) were continuously measured and recorded at 1-min intervals throughout the 60-min study period. Sufentanil, fentanyl, and alfentanil infusions were associated with a significant but transient increase in ICP (9+/-2 mm Hg [SD], 8+/-2 mm Hg, and 5.5+/-1 mm Hg, respectively; p<.05). The increase in ICP peaked at 5, 6, and 3 mins, respectively, then gradually decreased and returned to baseline values after 15 mins. This result was accompanied by a significant decrease in MAP (21+/-2 mm Hg, 24+/-2 mm Hg, and 26+/-2 mm Hg, respectively; p<.05) and, thus, in CPP (30+/-3 mm Hg, 31+/-3 mm Hg, and 34+/-3 mm Hg, respectively; p<.05). After 5 mins, MAP and CPP gradually increased, although they remained significantly decreased throughout the study period. No changes in lactate-oxygen index, used as an ischemia index, were observed. Changes in electroencephalogram tracings were characterized by a switch from a fast to a decreased activity, together with an improvement in the background activity. CONCLUSION: The results of the present study show that alfentanil, sufentanil, and fentanyl produce similar transient increases in ICP when administered by bolus injection in patients with increased ICP. No evidence of cerebral ischemia was observed in the study patients.

Adult↗
PubMed1999

Gamma knife surgery for mesial temporal lobe epilepsy.

PURPOSE: Gamma knife radiosurgery (GK) allows precise and complete destruction of chosen target structures containing healthy and/or pathologic cells, without significant concomitant or late radiation damage to adjacent tissues. All the well-documented radiosurgery of epilepsy cases are epilepsies associated with tumors or arteriovenous malformations (AVMs). Results prompted the idea to test radiosurgery as a new way of treating epilepsy without space-occupying lesions. METHODS: To evaluate this new method, we selected seven patients with drug-resistant "mesial temporal lobe epilepsy" (MTLE). The preoperative evaluation program was the one we usually perform for patients selected for microsurgery of TLE [video-EEG analysis of seizures, foramen ovale electrode recording, magnetic resonance imaging (MRI) positron emission tomography (PET) scan, neuropsychological testing]. In lieu of microsurgery, the amygdalohippocampectomy was performed by using GK radiosurgery. RESULTS: Morphologic (MRI) signs of destruction of the target took place at 9 months after GK surgery. Since the treatment day, the first patient has been seizure free. Seizure improvement came more gradually for the following patients, and complete cessation of seizures occurred around the tenth month (range, 8-15 months). MRI shows that the amygdaloentorhinohippocampal target was selectively injured. No significant side effect (except one case of homologous quadrantanopia) or morbidity and no mortality was observed. The current follow-up is 24-61 months, and all (but one) patients are seizure free. CONCLUSIONS: This initial experience proves clearly the short-to middle-term efficiency and safety of GK for MTLE surgery. These results need further confirmation of long-term efficiency, but the introduction of GK surgery into epilepsy surgery can reduce dramatically its invasiveness and morbidity.

Adult↗
PubMed1999

Early and delayed MR and PET changes after selective temporomesial radiosurgery in mesial temporal lobe epilepsy.

We report a patient with medically refractory mesial temporal lobe epilepsy treated by gamma knife radiosurgery. In lieu of a microsurgical procedure, an entorhinoamygdalohippocampectomy was performed with a gamma knife and low marginal doses (25 Gy). The clinical and imaging studies, including CT, MR imaging, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and long-term follow-up MR examinations, are reported. The patient has been seizure-free since the day of treatment, with no clinical complications. MR studies accurately depicted the effect on the target structures and the transient secondary changes around them. FDG-PET scans showed decreased metabolism after gamma knife surgery throughout the anteromesial part of the epileptogenic temporal lobe. This metabolic decrease was reversible in the lateral temporal cortex. Our case suggests that gamma knife surgery is a promising tool for use as a minimally invasive approach to the treatment of epilepsy.

Adult↗
PubMed1999

Radiosurgery for trigeminal neuralgia and epilepsy.

The role of Gamma Knife surgery in the field of functional surgery recently has evolved dramatically. For treatment of trigeminal neuralgia, Gamma Knife surgery is the least invasive procedure, with a low rate of hypesthesia. If a rate of complete relief similar to that of other surgical techniques could be achieved, this approach will become one of the main techniques used to treat the disease initially. The authors present their experience with a group of 16 patients with mesial temporal lobe epilepsy who have been treated successfully (15 completely seizure-free and 1 with rare, nondisabling seizures) without significant complication. After additional follow-up to demonstrate the absence of long-term consequences, this fascinating new approach could change epilepsy surgery practice dramatically.

Adult↗
PubMed1998

Unexpected homology between inducible cell wall protein QID74 of filamentous fungi and BR3 salivary protein of the insect Chironomus.

A gene, qid74, of mycoparasitic filamentous fungus Trichoderma harzianum and its allies encodes a cell wall protein that is induced by replacing glucose in the culture medium with chitin (simulated mycoparasitism conditions). Because no trace of this gene can be detected in related species such as Gibberella fujikuroi and Saccharomyces cerevisiae, the qid74 gene appears to have arisen de novo within the genus Trichoderma. Qid74 protein, 687 residues long, is now seen as highly conserved tandem repeats of the 59-residue-long unit. This unit itself, however, may have arisen as tandem repeats of the shorter 13-residue-long basic unit. Within the genus Trichoderma, the amino acid sequence of Qid74 proteins has been conserved in toto. The most striking is the fact that Qid74 shares 25.3% sequence identity with the carboxyl-terminal half of the 1,572-residue-long BR3 protein of the dipteran insect Chironomus tentans. BR3 protein is secreted by the salivary gland of each aquatic larva of Chironomus to form a tube to house itself. Furthermore, the consensus sequence derived from these 59-residue-long repeating units resembles those of epidermal growth factor-like domains found in divergent invertebrate and vertebrate proteins as to the positions of critical cysteine residues and homology of residues surrounding these cysteines.

Amino Acid Sequence↗
PubMed1998

The impact of stereotactic large-core needle biopsy in the treatment of patients with nonpalpable breast lesions: a study of diagnostic accuracy in 510 consecutive cases.

The objective of this study was to assess the usefulness of stereotactic large-core needle biopsy (LCNB) in the management of nonpalpable breast lesions (NBL) and compare it with stereotactic fine-needle aspiration biopsy (SFNA) performed simultaneously in a significant number of cases. From November 1993 through June 1997, 510 consecutive patients with NBL underwent 14-gauge LCNB with 354 women undergoing simultaneous 21-gauge SFNA in the same lesson. Mammographic findings lesion size, number of core biopsy specimens, complications and diagnoses of both techniques were analysed. Surgical biopsy, tumorectomy or mastectomy was indicated for malignancy or poor correlation between SFNA or LCNB results and clinical or radiological findings. Values of diagnostic accuracy of both LCNB and SFNA were determined. The ratio benign surgical biopsies/malignant surgical biopsies (BB/CB) of the series was calculated. A total of 171 patients underwent surgical treatment: in 31 (18.1%) a benign process or atypical ductal hyperplasia was the final diagnosis. The ratio BB/CB was 0.22. Sensitivity and specificity were 93.2 and 100%, respectively, for LCNB, and 77.2 and 92.3%, respectively, for SFNA with cytological analysis. Large-core needle biopsy provides more accurate diagnosis than SFNA in the management of nonpalpable breast lesions and obviates a surgical diagnostic procedure in a significant number of cases.

Aged↗
PubMed1998

[Waiting for the end of poliomyelitis. Setting of the last phase of the eradication program. National Commission for the Certification of the Eradication of Poliomyelitis].

The worldwide eradication of poliomyelitis is expected within a few years. A reinforcement of epidemiological, clinical and viral supervision is necessary. Besides a sustained immunization effort, particular attention is required from all clinicians concerning the cases of non-traumatic acute flacid palsy that they may observe. In these cases it is asked to clinicians to perform a search for enterovirus in stool and spinal fluid, and a poliomyelitis serology.

Cerebrospinal Fluid↗
PubMed1998

A multicentre serosurvey on diphtheria immunity in a French population of 1004 subjects.

Diphtheria immunity was determined in serum specimens obtained in 1994 from 1004 subjects seen in emergency departments of three distant French cities. An enzyme immunoassay was used to measure serum diphtheria antitoxin concentrations according to the following criteria: (a) antitoxin < 0.01 IU/ml: susceptibility, (b) 0.01-0.09 IU/ml: basic protection, (c) > or = 0.10 IU/ml: full protection. Among these patients, 20.3% were fully susceptible to diphtheria, 30.3% had basic but doubtful protection and only 49.4% were fully protected. Protection was different by age-groups: 73.5% of the subjects under 40 years of age, 46% between 40 and 65 and 33% over 65 were fully protected. Protection decreased with increasing age (p < 0.001)and was greater for men than women after 40 years of age (p < 0.001). The results of this exploratory study indicate that the enhancement of diphtheria immunity by boosters in adult population should be reconsidered in France as well as in many industrialized countries.

Adolescent↗
PubMed1998

Pigmented squamous cell carcinoma of the skin: report of two cases and review of the literature.

Melanoma is the most common malignant tumor in which melanin synthesis occurs, although other nonmelanocytic tumors synthesize melanin or contain nonneoplastic melanocytes. We present two cases of infiltrating pigmented squamous cell carcinoma of the skin and review the clinical, morphologic, and ultrastructural features. Melanin was found in epithelial tumor cells as well as in macrophages and dendritic melanocytes. Interestingly, one of the neoplasms was associated with an adjacent melanocytic nevus and pigmented solar keratosis. Immunohistochemical analysis showed that neoplastic cells stained for keratin and melanin-filled dendritic cells were found to be S-100 protein and HMB45 positive. A careless examination of the immunohistochemical stains for S-100 protein and HMB45 could cause the misdiagnosis of melanoma, a neoplasm that has a more ominous outlook.

Aged↗
PubMed1998

Effect of gamma knife radiosurgery on rat brain sodium channel subunit mRNA expression.

Several lines of evidence underscore a possible and delayed antiepileptic effect of Gamma Knife irradiation. This effect could be related to structural and molecular changes. Since voltage-gated Na+ channels (NaChs) play a crucial role in neuron excitability, we studied the effect of Gamma Knife (GK) irradiation on the distribution of Na+ channel (NaCh) subunit mRNAs in rat brains. A left side irradiation was performed in rats using a stereotactic device adapted for GK radiosurgery. A dose of 100 Gy was administered with the 4 mm collimator. The left dentate gyrus and thalamus coordinates were based on De Groot's rat stereotactic atlas. The isodose curve distribution was calculated with the dose planning software used in Gamma Knife and superimposed on the target. Na+ channels alpha unit and mRNAs (subtype II and subtype III) expression was studied 1 hour, 30 days and 60 days later. We used non-radioactive in situ hybridization with subtype-specific digoxigenin-labeled cRNA probes. Labeling intensity was evaluated with a densitometric analysis of digitized images from the control side (right) and lesioned side (left) in each rat. No morphological changes were observed one hour after GK irradiation. 30 days later, the upper thalamic nuclei exhibited a few necrotic regions associated with gliosis. In contrast, no lesions were observed in the hippocampus. 60 days later, the necrotic region involving thalamic nuclei was enlarged. NaCh II and III mRNAs expression did not appear to be modified after GK at the three times studied here. In particular, neurons surrounding the GK necrosis continued to express high levels of NaCh mRNAs. Thus, regulation of NaCh II and III subtypes do not appear to explain the functional antiepileptic effect of GK.

Animals↗
PubMed1998

Empirical therapy for nonhospitalized patients with community-acquired pneumonia. Study Group of General Practitioners.

A prospective survey involving a group of 95 general practitioners (GPs) in France was conducted to describe antibiotic therapy prescribed for out-patients with community-acquired pneumonia (CAP). A total of 173 cases of CAP, defined by the association of fever and pulmonary focal crackles and/or radiological changes consistent with a pulmonary infection, were reported between February 1993 and March 1994: 84 males and 89 females (mean age: 48 yrs) of whom 45% had no underlying disease. Nineteen (11%) were immediately hospitalized and the remaining 154 out-patients were treated without microbiological investigation. First-line antibiotic therapy was amoxicillin or amoxicillin-clavulanic acid combination (57%), a first or second generation cephalosporin (12%), ceftriaxone (8%), oral broad-spectrum cephalosporin (3%), a macrolide (16%), a tetracycline (1%) and a fluoroquinolone (2%). A total of 120 (78%) patients recovered with no change in treatment and 34 (22%) patients failed to improve: 18 were hospitalized and 16 had a second-line therapy, mainly a macrolide or a quinolone. Five patients died at hospital. The overall mortality was 3%, and 14% in hospitalized patients. Empirical therapy using a betalactam to target a presumed pneumococcal infection, in agreement with European guidelines, is appropriate for out-patients with mild lobar community-acquired pneumonia.

Adolescent↗