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Biomedical subjects

G Aubert

Publications and source records attributed to G Aubert.

At least 19 recordsLinked to original sources

The gene for Bazex-Dupré-Christol syndrome maps to chromosome Xq.

Bazex-Dupré-Christol syndrome is an inherited condition with skin cancer predisposition characterized by follicular atrophoderma, hypotrichosis, and early onset of multiple basal cell carcinomas. Previous reports suggested an X-linked mode of inheritance. We therefore performed linkage analysis with microsatellite markers of the X chromosome in three families. We obtained evidence for X-linkage and regional assignment to Xq24-q27 of this syndrome (maximal lod score = 5.26 with a recombination fraction of 0% at the DXS1192 locus). This represents a first step towards the identification of a gene involved in hair follicle development and skin tumor formation.

Basal Cell Carcinoma

Effects of nasal positive-pressure hyperventilation on the glottis in normal awake subjects.

We have recently observed obstructive apneas during nasal intermittent positive-pressure ventilation (nIPPV) and suggested that they were due to hypocapnia-induced glottic closure. To confirm this hypothesis, we studied seven healthy subjects and submitted them to nIPPV while their glottis was continuously monitored through a fiber-optic bronchoscope. During wakefulness, we measured breath by breath the widest inspiratory angle formed by the vocal cords at the anterior commissure along with several other indexes. Mechanical ventilation was progressively increased up to 30 l/min. In the absence of diaphragmatic activity, increases in delivered minute ventilation resulted in progressive narrowing of the vocal cords, with an increase in inspiratory resistance and a progressive reduction in the percentage of the delivered tidal volume effectively reaching the lungs. Adding CO2 to the inspired gas led to partial widening of the glottis in two of three subjects. Moreover, activation of the diaphragmatic muscle was always associated with a significant inspiratory abduction of the vocal cords. Sporadically, complete adduction of the vocal cords was directly responsible for obstructive laryngeal apneas and cyclic changes in the glottic aperture resulted in waxing and waning of tidal volume. We conclude that in awake humans passive ventilation with nIPPV results in vocal cord adduction that depends partly on hypocapnia, but our results suggest that other factors may also influence glottic width.

Adult

Effects of nasal positive-pressure hyperventilation on the glottis in normal sleeping subjects.

We have previously observed that, in normal awake subjects passively hyperventilated with intermittent positive-pressure ventilation delivered through nasal access (nIPPV), the glottis could interfere with the ventilation. We report on data obtained in the same subjects during stable sleep. In all cases, the glottis was continuously observed through a fiber-optic bronchoscope, and other indexes were also continuously recorded. Mechanical ventilation was progressively increased up to 30 l/min. We have observed during passive nIPPV in stable sleep that increases in delivered minute ventilation (VEd) resulted in progressive narrowing of the glottic aperture, with increases in inspiratory resistance and progressive reductions in the percentage of the delivered tidal volume effectively reaching the lungs. For a given level of VEd, comparisons showed that the glottis was significantly narrower during sleep than during wakefulness and that the glottis was significantly narrower during stage 2 than during stages 3/4 non-rapid-eye-movement sleep. Moreover, when CO2 is added to the inspired air, glottic aperture increased in five of nine trials without changes in sleep stage. We also observed a significant negative correlation between glottic width and the VED, independent of the CO2 level. We conclude that during nIPPV glottis narrowing results in a decrease in the proportion of the delivered tidal volume reaching the lungs.

Adult

Normal pregnancy in primary alveolar hypoventilation treated with nocturnal nasal intermittent positive pressure ventilation.

Nocturnal nasal intermittent positive pressure ventilation (NIPPV) is increasingly used to treat chronic respiratory failure in a wide variety of conditions (myopathies, Ondine's curse, kyphoscoliosis, etc.) and allows a normal everyday life. Some of these diseases affect women of childbearing age. We report on a young woman suffering from primary alveolar hypoventilation, who presented with limitation of daytime activities, severe oxygen desaturation during sleep, polycythaemia and pulmonary hypertension. These abnormalities completely reversed after a few months of NIPPV applied through a nasal mask. Whilst under ventilatory assistance during sleep, she had an uneventful pregnancy and delivery of a normal baby. We suggest that in selected patients requiring NIPPV, pregnancy can be contemplated with a reasonable level of safety both for the mother and the child, provided that adequate mechanical ventilatory assistance during sleep is maintained throughout pregnancy.

Adult

Nasal continuous positive airway pressure in the perioperative management of patients with obstructive sleep apnea submitted to surgery.

Anesthetic, sedative, and analgesic drugs have been shown in animals and humans to selectively impair upper airway muscle activity. In patients with an already compromised upper airway, these drugs may further jeopardize upper airway patency, especially during sleep. Thus, patients with obstructive sleep apnea syndrome (OSAS) are at high risk for surgery because of the use of the aforementioned drugs in the perioperative period. It has been recommended that such drugs should be avoided or used with extreme caution in patients with OSAS submitted to surgery. We report herein on 16 adult patients with documented OSAS undergoing various types of surgical procedures, including coronary artery bypass surgery. Anesthesia was carried on with the usual type of drugs for each type of surgery. Postoperative opioid analgesia and sedation were not restricted. The first patient, whose OSAS was diagnosed but not treated, died after various complications, including a respiratory arrest in the ward. The second patient experienced serious postoperative complications until a treatment for OSAS with nasal continuous positive airway pressure (N-CPAP) was instituted, and thereafter he made an uneventful recovery. The 14 following patients were started on N-CPAP before surgery, were put on N-CPAP as soon as extubated, on a near-continuous basis, for 24 to 48 h and thereafter for all sleep periods. None of them had major complications. The intensive care unit and hospital stays were the normal ones for each type of surgery in our institution. We conclude that N-CPAP started before surgery and resumed immediately after extubation allowed us to safely manage a variety of surgical procedures in patients with OSAS, and to freely use sedative, analgesic, and anesthetic drugs without major complications. Every effort should be made to identify patients with OSAS and institute N-CPAP therapy before surgery.

Adult

[Follicular atrophoderma, basal cell proliferation and hypotrichosis (Bazex-Dupré-Christol syndrome). A study in 2 families].

We describe a new case of Bazex, Dupré and Christol (BDC) syndrome in a family (family B...) where the disease affects four generations. Moreover, we report the clinical and genealogical evolution of the first family (family A...), described in 1966 by Bazex. A review of the literature has enabled us to collect the various symptoms of BDC syndrome, to discuss the relationship of this syndrome with basal cell naevomatosis and X-linked dominant chondrodysplasia punctata, and to discuss the kind of heredity. In family B..., two patients were examined. A one-month-old girl, with hypotrichosis and pseudo pili torti, and her 29-year-old father, with hypotrichosis and dorsal follicular atrophoderma of the hands. In this family, the paternal grand mother, one of her sisters, and the great grand father were also affected, but no basal cell carcinomas were found. In family A..., five patients were followed up. Four brothers, adult men aged 43 to 55 years initially presented only dorsal follicular atrophoderma the hands and face, hypotrichosis and numerous basal cell carcinomas of the face, especially in palpebral, temporal, nasal and forehead sites. Surgery was required and gave better results than radiotherapy, which left sites of sclerosis. Their mother was also affected and had been treated for numerous basal cell carcinomas of the face. The other members of the same generation (two women, two men) were unaffected. But the uncle and the grand father had the disease and at the last generation, a girl, child of one of the brothers affected, presented follicular atrophoderma and hypotrichosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

[The role of the bacteriological laboratory in the criteria for choosing and monitoring antibiotic treatment].

The constant development of clinical bacteriology and the consequence this has on the way an infected patient is approached and treated require that be examined a bacteriology laboratory's contribution in choosing and monitoring an antibiotic treatment. In the economic context of hospitals, one of the aims is to rationalize the prescription of biological investigations, as well as that of antibiotic treatments. The patient's history, his clinical state as well as the place where he has been admitted must be taken into account to establish, together with microbiologists, a hierarchy of the biological investigations required and to adapt the antibiotic treatment. In the laboratory, both the bacteriostatic and bactericidal sensitivity to antibiotics may be assessed in vitro. The best therapeutic antibiotic concentrations may be obtained by monitoring the pharmacokinetics of antibiotics.

Anti-Bacterial Agents

Emergence of quinolone-imipenem cross-resistance in Pseudomonas aeruginosa after fluoroquinolone therapy.

Emergence of resistance to fluoroquinolones was observed in two clinical isolates of Pseudomonas aeruginosa after ciprofloxacin or norfloxacin monotherapy. In the first case, the resistant variants exhibited quinolone-imipenem cross-resistance (MIC of norfloxacin and ciprofloxacin: 16 mg/L; MIC of imipenem: 8 mg/L), although the patient had never received imipenem treatment, while the strain from the second case remained imipenem-susceptible (MIC of norfloxacin or ciprofloxacin: 8 mg/L; MIC of imipenem: 2 mg/I). The frequency of in-vitro emergence of variants resistant to imipenem and fluoroquinolones was studied for the two strains, with imipenem or fluoroquinolones as selecting agents. Ciprofloxacin and three other quinolones (norfloxacin, temafloxacin and tosufloxacin) selected imipenem-resistant variants in a similar way to imipenem for the first strain, but not for the other. In contrast, imipenem did not select quinolone-resistant variants from either strain. For both strains, killing curves demonstrated that a bactericidal effect could be obtained with a drug combination (2 x MIC of ciprofloxacin and 2 x MIC of imipenem) without any selection of resistant mutants after 24 h, thereby suggesting the possible use of this combined regimen for treating severe P. aeruginosa infection.

Anti-Infective Agents

Alternative therapeutic approaches in sleep apnea syndrome.

A number of therapeutic alternatives to continuous positive airway pressure (CPAP) and surgery have been proposed to treat sleep apnea syndrome. Nasopharyngeal intubation may provide an immediate, simple and cost-effective means of bypassing upper airway obstruction during sleep. Tolerance is good in small children but is lower, between 30 and 40%, in adults. Clinical improvement is reported by more than half of the patients treated with this device and is confirmed by polysomnography. However, in most of these subjects, breathing during sleep is only partially corrected and sleep remains fragmented. Nasopharyngeal intubation should be proposed in infants, in patients who do not tolerate CPAP or as a therapeutic substitute for CPAP during holidays or traveling. The tongue retaining device and variants of orthodontic appliances have been proposed in order to increase upper airway patency. Tolerance is low, efficacy is usually incomplete and limited to patients with moderate forms of SAS, and long-term follow-ups are scarce. Sleep position training has been advocated as a means of reducing time spent in the supine position. Long-term efficacy has not been proven. Weight loss by caloric restriction or surgical procedures produces a variable improvement of sleep architecture and breathing during sleep. It should be proposed to all patients with SAS, as cure has been achieved in a few patients with the adjunction of weight loss and another treatment modality.

Adult

Immunoblotting patterns with Mycoplasma pneumoniae of serum specimens from infected and non-infected subjects.

Two hundred and ninety-four serum specimens from 248 subjects, whose complement fixation (CF) titres to Mycoplasma pneumoniae were known, were further investigated by IgG immunoblotting. After analysis of M. pneumoniae proteins by SDS-PAGE, nine polypeptides (p) with mol. wts of 180-43 Kda were selected for immunoblotting studies. Antibodies to M. pneumoniae measured by immunoblotting appeared progressively with age; most subjects more than 19 years old gave positive results. For most of the polypeptides, there was an increase in the frequency of band detection when the CF titres were higher. Furthermore, paired serum specimens from 10 patients with M. pneumoniae infection, as demonstrated by a rise in CF antibody titre, were tested for IgG blotting patterns. Generally, p180 (the P1 adhesin of M. pneumoniae), p172 and p84 were shown to be the dominant targets of the immune response to this organism and may have diagnostic value.

Adolescent

Evaluation of five commercial tests: complement fixation, microparticle agglutination, indirect immunofluorescence, enzyme-linked immunosorbent assay and latex agglutination, in comparison to immunoblotting for Mycoplasma pneumoniae serology.

A panel of 68 serum specimens from 41 subjects exhibiting various immunological patterns to Mycoplasma pneumoniae as determined by detection of a 180 kDa protein in immunoblotting was used to compare five commercially available tests based on different methods: complement fixation test (CFT), microparticle agglutination (MAG), indirect immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (Elisa), and latex agglutination (LA). The tests were performed according to the manufacturers' instructions. For the determination of immunity to M pneumoniae, the five tests were in good accordance with immunoblotting: sensitivity was 100% for all the five assays, specificity ranged from 95.6% (MAG) to 82.6% (Elisa) and overall agreement ranged from 98.2% (MAG) to 92.8% (Elisa). The comparisons of antibody rates obtained by the four quantitative tests (CFT, MAG, IFA, Elisa) showed correlation coefficients ranging from 0.87 (CFT-IFA) to 0.67 (CFT-Elisa). Six significant antibody rises demonstrated by immunoblotting patterns were detected by all the tests but Elisa in one case. As a whole, the commercial assays gave satisfactory results for routine determination of immune status to M pneumoniae: CFT was the cheapest test and MAG and LA were the easiest to perform.

Adolescent

[Study of serum kinetics of vancomycin during the "antibiotic-lock" technique].

The serum kinetics of vancomycin was studied in two patients aged 3 and 15 years during antibiotic therapy for catheter related sepsis associated with Staphylococcus epidermidis. Vancomycin was administered, simultaneously, by parenteral conventional doses (30 mg/kg/day div q 8 h) and using the antibiotic-lock technique in the infected catheter at a high concentration (150 mg/ml) during one hour, 3 hours after each infusion. Pharmacokinetics data did not show any significant change in the serum kinetics of the antibiotic. The results suggest that delivering a high concentration of vancomycin in the infected catheter using the lock technique may be useful to sterilize infected catheter without toxic effect.

Adolescent

[In vitro bactericidal effect of temafloxacin and tosufloxacin against streptococci].

Tosufloxacin tosylate (TOSU) and temafloxacin hydrochloride (TEMA) were tested in vitro against 248 clinical isolates of various species of streptococci recovered in a hospital microbiology laboratory (Bellevue Regional Teaching Hospital). Species included S. pneumoniae (n = 20), group A streptococci (n = 22), group B streptococci (n = 30), group G streptococci (n = 17), group D S. bovis (n = 19), Enterococcus faecium (n = 45), Enterococcus faecalis (n = 28), S. sanguis (n = 21), S. milleri (n = 29) and S. mitis (n = 17). Activities of each of the two study drugs were evaluated comparatively with two other fluoroquinolones, i.e., ciprofloxacin (CIP) and pefloxacin (PEF). Activities of each of these four antibiotics, expressed as the MIC 90%, varied as follows according to the species of streptococci: TOSU, 0.25 to 1 mg/l, TEMA 0.5 to 2 mg/l, CIP, 1 to 4 mg/l and PEF 8 to 32 mgl. Overall, TOSU and TEMA exhibited the greatest activity of the various species. The size of the inoculum had no significant effect on MIC values.

Anti-Infective Agents

[In vitro effect of new fluoroquinolones and betalactamines combinations against enterococci].

Combinations of one of the new fluoroquinolones (ciprofloxacin, temafloxacin or tosufloxacin) with a betalactam (amoxicillin, piperacillin, or imipenem) were tested in vitro using the checkboard method against 28 strains of Streptococcus faecalis recovered in 1990 from a variety of specimens. No instance of antagonism (FIC greater than 2) was recorded. Effects of the two agents were usually additive (0.5 less than FIC less than or equal to 1). An indifferent effect (1 less than FIC less than or equal to 2) was seen in 32.1% of cases (9 strains) with the amoxicillin-tosufloxacin combination. Synergy (FIC less than or equal to 0.5) was uncommon with combinations including imipenem: effects were synergistic for only three strains with imipenem and either ciprofloxacin or tosufloxacin and for six strains with the imipenem-temafloxacin combination. Synergy was more common with combinations including ciprofloxacin and either piperacillin (10 strains, 35.7%) or amoxicillin (13 strains, 46.4%).

Amoxicillin