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Biomedical subjects

M Andre

Publications and source records attributed to M Andre.

At least 19 recordsLinked to original sources
PubMed2005

Drift-kinetic Alfvén waves observed near a reconnection X line in the earth's magnetopause.

We identify drift-kinetic Alfvén waves in the vicinity of a reconnection X line on the Earth's magnetopause. The dispersive properties of these waves have been determined using wavelet interferometric techniques applied to multipoint observations from the Cluster spacecraft. Comparison of the observed wave dispersion with that expected for drift-kinetic Alfvén waves shows close agreement. The waves propagate outwards from the X line suggesting that reconnection is a kinetic Alfvén wave source. Energetic O+ ions observed in these waves indicate that reconnection is a driver of auroral ion outflow.

Journal Article↗
PubMed2005

Ionic liquids as advantageous solvents for headspace gas chromatography of compounds with low vapor pressure.

The potential of ionic liquids as solvents for headspace gas chromatography was investigated. Three compounds with boiling points above 200 degrees C were selected to demonstrate the feasibility of the concept described. 2-Ethylhexanoic acid, formamide, and tri-n-butylamine as examples of acidic, neutral, and basic analytes were dissolved in acidic 1-n-butyl-3-methylimidazolium hydrogen sulfate (1), neutral 1-n-butyl-2,3-dimethylimidazolium dicyanamide (2), and 2 containing 1,8-diazabicyclo[5.4.0]undec-7-ene to adjust basic conditions. All analytes could be determined with limits of detection and limits of quantification in the low-ppm concentration range.

Ampicillin↗
PubMed2005

[Delayed and fortuitous diagnosis of right diaphragmatic rupture during preoperative evaluation].

Although diaphragmatic rupture occurs after violent blunt trauma, its diagnosis is often delayed. The intra-thoracic displacement of abdominal organs through diaphragmatic rupture may lead to early or delayed complications because of compression of heart and lungs or strangulation of the abdominal viscera. A 49-year-old woman was scheduled to undergo elective lumbar disc surgery in prone position. The preoperative chest radiograph revealed an abnormally elevated right hemi diaphragm with loops of colon filling the right costophrenic angle. The CT-scan confirmed right chronic diaphragmatic rupture with colon and liver herniations. Fifteen months previously, this woman had been involved in a traffic accident, with blunt right trauma resulting in right pelvic fractures. Perianaesthetic course increase the pre-existing mechanical risk of complications of chronic diaphragmatic rupture. Primary repair of right chronic diaphragmatic rupture through thoracotomy must be recommended. When another surgery must be done in emergency, the feasibility of regional anaesthesia should be considered.

Accidents, Traffic↗
PubMed2001

Cytogenetic responses in high-risk myelodysplastic syndrome following low-dose treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine.

Decitabine (5-aza-2'-deoxycytidine) acts as a powerful demethylating agent in vitro. Clinically, low-dose decitabine ameliorates cytopenias including induction of trilineage responses in approximately 50% of patients with high-risk myelodysplastic syndrome (MDS). We examined the incidence and kinetics of cytogenetic responses to decitabine in these patients. Of 115 successfully karyotyped patients, 61 (53%) had clonal chromosomal abnormalities prior to treatment. Major cytogenetic responses were observed in 19 patients (31% of those with abnormal cytogenetics, 17% of all patients by intention-to-treat) after a median of three courses (range, 2-6) until best cytogenetic response. Progressive decrease of the abnormal clone over time was also determined using fluorescence in situ hybridization (FISH) analysis in two patients. Median duration of cytogenetic responses was 7.5 months (range, 3-15). Analysis of response by the International Prognostic Scoring System (IPSS) cytogenetic risk groups revealed three out of five cytogenetic responses (60%) in the IPSS 'low-risk' group, 6 out of 30 with 'intermediate risk' (20%) and 10 out of 26 in the 'high-risk' group (38%). Median survival in these cytogenetic subgroups was 30, 8 and 13 months respectively. The relative risk of death in patients achieving a major cytogenetic response was 0.38 (95% confidence interval 0.17-0.88) compared with patients in whom the cytogenetically abnormal clone persisted (P = 0.0213). In conclusion, repeated courses of low-dose decitabine induce cytogenetic remissions in a substantial number of elderly MDS patients with pre-existing chromosomal abnormalties; these are associated with improved survival compared with patients in whom the cytogenetically abnormal clone persists. Patients with 'high-risk' chromosomal abnormalities may particularly benefit from this treatment.

Adult↗
PubMed2001

Processing of vitamin A and E in the human gastrointestinal tract.

We aimed to provide basic data on the processing of vitamin A and E in the human gastrointestinal tract and to assess whether the size of emulsion fat globules affects the bioavailability of these vitamins. Eight healthy men received intragastrically two lipid formulas differing in their fat-globule median diameter (0.7 vs. 10. 1 microm. Formulas provided 28 mg vitamin A as retinyl palmitate and 440 mg vitamin E as all-rac alpha-tocopherol. Vitamins were measured in gastric and duodenal aspirates, as well as in chylomicrons, during the postprandial period. The gastric emptying rate of lipids and vitamin A and E was similar. The free retinol/total vitamin A ratio was not significantly modified in the stomach, whereas it was dramatically increased in the duodenum. The proportion of ingested lipid and vitamins was very similar in the duodenal content. The chylomicron response of lipids and vitamins was not significantly different between the two emulsions. Our main conclusions are as follows: 1) there is no significant metabolism of vitamin A and E in the human stomach, 2) the enzyme(s) present in the duodenal lumen is significantly involved in the hydrolysis of retinyl esters, and 3) the size of emulsion fat globules has no major effect on the overall absorption of vitamin A and E.

Adult↗
PubMed2000

Adjunctive salvage therapy with inhaled aminoglycosides for patients with persistent smear-positive pulmonary tuberculosis.

A proportion of patients with drug-resistant and drug-susceptible tuberculosis (TB) have sputum that is smear and culture positive for Mycobacterium tuberculosis for a prolonged period of time, despite conventional therapy. Among such patients with refractory TB, an unblinded, observational study was undertaken that used conventional TB therapy and adjunctive aerosol aminoglycosides. Patients with persistent smear- and culture-positive sputum for M. tuberculosis (despite > or =2 months of optimal systemic therapy) were selected for adjunctive treatment via inhalation with aminoglycosides, and microbiological responses were monitored. Thirteen of 19 patients converted to smear negativity during the study: 6 of 7 with drug-susceptible TB and 7 of 12 with drug-resistant TB. Among patients with drug-susceptible TB, the median time to sputum conversion was 23 days, a shorter time than for a population of historical control patients. Recurrent infection was not observed. Adjunctive aerosol aminoglycosides may expedite sterilization of sputum among certain patients with refractory TB and diminish the risk of transmission.

Administration, Inhalation↗
PubMed2000

Normal EEG in very premature infants: reference criteria.

OBJECTIVES: Objectives were to precise EEG criteria of normality in very premature infants. METHODS: The neonatal electroencephalograms (EEGs) of 17 neurologically normal very premature infants recorded at a conceptional age (CA) of 26-28 weeks have been analyzed. The normality of the infants was defined as normal neonatal cranial ultrasound scans and normal neurological outcome at a minimum postnatal age of 2 years. RESULTS: All tracings were discontinuous. The bursts (amplitude >/=30 microV) were interhemispherically synchronous and lasted up to 3 min. The interburst intervals lasted up to 46 s. EEG patterns consisted mainly of slow waves (</=3 Hz), with high amplitude (up to 300 microV), occipital predominance and superimposed alpha, beta and theta rhythms. High amplitude theta rhythms predominated on temporal areas, beta rhythms were mainly central, whereas alpha rhythms were central and occipital. Sleep state differentiation began as early as 26 weeks CA. On a given trace, the existence of more mature graphoelements than expected for the CA reflected a normal increasing maturation. CONCLUSIONS: EEG has constant and reproductible patterns in normal very premature infants. This can constitute a basis for the determination of EEG criteria for neurological prognosis in infants of 26-28 weeks CA.

Brain↗
PubMed2000

Low-dose 5-aza-2'-deoxycytidine, a DNA hypomethylating agent, for the treatment of high-risk myelodysplastic syndrome: a multicenter phase II study in elderly patients.

PURPOSE: 5-Aza-2'-deoxycytidine (decitabine; DAC) is a DNA hypomethylating agent that has shown a 50% response rate in a small phase II study in elderly patients with high-risk myelodysplastic syndrome. We performed a second, multicenter phase II study in a larger group of patients to confirm our findings and to study the toxicity of DAC. PATIENTS AND METHODS: Between June 1996 and September 1997, 66 patients (median age, 68 years) from seven centers received DAC 45 mg/m(2)/d for 3 days every 6 weeks. For patients in whom a complete response (CR) was reached after two courses, two further cycles were administered as consolidation therapy. In case of a stable disease situation, improvement, or a partial response (PR), a maximum of six cycles was administered. The primary end points were response rate and toxicity. The secondary end points were response duration, survival from the start of therapy, and overall survival. RESULTS: The observed overall response rate was 49%, with a 64% response rate in the patients with an International Prognostic Scoring System (IPSS) high-risk score. The actuarial median response duration was 31 weeks, with a response duration of 39 weeks and 36 weeks for patients who reached a PR or CR, respectively. The actuarial median survival time from the time of diagnosis was 22 months and from the start of therapy was 15 months. For the IPSS high-risk group, the median survival time was 14 months. The median progression-free survival time was 25 weeks. Myelosuppression was rather common, and the treatment-related mortality rate was 7% and was primarily associated with pancytopenia and infection. Significant responses were observed with regard to megakaryopoiesis, with increases in platelet counts having already occurred after one cycle of DAC therapy in the majority of the responding patients. CONCLUSION: We were able to confirm our previous observation that DAC therapy was effective in half of the studied patients with high-risk myelodysplastic syndrome and is especially active in the patients with the worst prognoses. Myelosuppression was the only major adverse effect observed.

Adult↗
PubMed2000

Assessment of ophthalmology residents' contact lens training.

PURPOSE: To characterize the nature and duration of contact lens training in ophthalmology residency training programs and to ascertain the comfort level of residents in fitting various types of contact lenses and in dealing with common contact lens-related complications. METHODS: Surveys were mailed to 126 ophthalmology residency program directors/coordinators and requested to be distributed to 1,381 ophthalmology residents. The questionnaire addressed issues related to contact lens training, hours of clinical and didactic training, comfort with fitting a variety of different types of contact lenses and dealing with common contact lens-related complications, and plans for incorporation of contact lens dispensing into future practice. RESULTS: Two hundred and forty-nine residents (18%) responded from 84 programs (67%). Most programs (87%) have some form of supervised contact lens training, frequently conducted by an optometrist (61% of programs), that consists of 20 hours or less of clinical experience and 20 hours or less of didactic training. A majority of the responding graduating residents (66%) feel comfortable fitting spherical soft contact lenses, while less than half of all residents feel comfortable fitting any other type of contact lens. In addition, most residents (65%) feel comfortable diagnosing and treating common contact lens-related complications. CONCLUSIONS: Most ophthalmology residency programs offer some form of supervised contact lens training which allows a majority of residents to feel comfortable fitting only spherical soft contact lenses, while also dealing comfortably with most contact lens-related problems. A comparison with previous data suggests increasing comfort with fitting most types of contact lenses over the last decade.

Contact Lenses↗
PubMed1999

Epidermal expression of apolipoprotein E gene during fin and scale development and fin regeneration in zebrafish.

Apolipoprotein E (apoE) plays an important role in systemic and local lipid homeostasis. We have examined the expression of apoE during morphogenesis and regeneration of paired and unpaired fins and during scale development in zebrafish (Danio rerio). In situ hybridization analysis revealed that, during embryogenesis, apoE is expressed in the epithelial cells of the median fin fold and of the pectoral fin buds. ApoE remains expressed in the elongating fin folds throughout development of the fins. During the larval to juvenile transition, apoE transcripts were present in the distal, interray and lateral epidermis of developing fins. Furthermore, as scale buds started to form, apoE was expressed in large scale domains which later, became restricted to the external posterior epidermal part of scales. A low level of transcripts could be observed at later developmental stages at these locations probably because fins and scales continue to grow throughout the animal's life. During regeneration of both pectoral and caudal fins, a marked increase in apoE expression is observed as early as 12 hours after amputation in the wound epidermis. High levels of apoE transcripts are then localized primarily in the basal cell layer of the apical epidermis. The levels of apoE expression were maximum between the second to fourth days and then progressively declined to basal level by day 14. ApoE transcripts were also observed in putative macrophages infiltrated in the mesenchymal compartment of regenerating fins a few hours after amputation. In conclusion, apoE is highly expressed in the epidermis of developing fins and scales and during fin regeneration while no expression can be detected in the skin of the trunk. ApoE may play a specific role in fin and scale differentiation at sites where important epidermo-dermal interactions occur for the elaboration of the dermal skeleton and/or for lipid uptake and redistribution within these rapidly growing structures.

Animals↗
PubMed1999

Synergies between plant research conducted for terrestrial and for space purposes.

During the past 10 years, the main part of CELSS studies has concerned the exploration of limits of plant productivity. Very high yields were obtained in continuous and high lighting, without reaching any limit. Concepts of mineral nutrition were renewed. CELSS activities now induce a development in the techniques of image processing applied to plants in order to follow the growth, to detect stresses or diseases or to pilot harvesting robots. Notable efforts concern the development of sensors, the study of trace contaminants and the micro-organisms monitoring. In parallel, several instruments for plant culture in closed Systems were developed. The advantages of closure are emphasised in comparison with open flow systems. The concept of Artificial Ecosystems developed for space research is more and more taken into account by the scientific community. It is considered as a new tool to study basic and applied problems related to ecology and not especially concerned with space research.

Ecological Systems, Closed↗
PubMed1999

Growth of wheat under one tenth of the atmospheric pressure.

Wheat plants were grown in twin closed growth chambers under normal and reduced atmospheric pressures. For the first 22 days from sowing, the reduced pressure was maintained at 200 hPa, and at 100 hPa for the remaining 27 days until harvest. These pressures were obtained by evacuation of the chamber and adding oxygen (170 and 79 hPa respectively) and carbon dioxide (0.65 and 1.0 hPa respectively; about 2 and 3 times above the control). Eighty-seven per cent of the final dry mass was produce under 100 hPa treatment. Growth and development of wheat are not negatively affected by low pressure treatment. Compared to the control, final dry mass increased by 76%, leaf number by 133%, and ear number by 35%, probably due to elevation of CO2. Shortening of shoot parts and increases in chlorophyll and proteins content are not in accordance with a predicted CO2 effect and could be attributed to the N2 removal and the subsequent alteration in gas diffusion rate.

Atmospheric Pressure↗
PubMed1999

A simplified closed artificial ecosystem--recycling of organic matter into wheat plants.

A simplified closed system consisting of a plant growth chamber coupled to a decomposition chamber was used to study carbon exchange dynamics. The CO2 produced via the decomposition of wheat straw was used for photosynthetic carbon uptake by wheat plants. The atmosphere of the two chambers was connected through a circuit of known flow rate. Thus, monitoring the CO2 concentrations in both compartments allowed measurement of the carbon exchange between the chambers, and estimation of the rate of respiration processes in the decomposition chamber and photosynthetic rate in the producer chamber. The objective for CELSS research was to simulate a system where a compartment producing food via photosynthesis, would be supplied by CO2 produced from respiration processes. The decomposition of biomass by the decomposer simulated both the metabolism of a crew and the result of a recycling system for inedible biomass. Concerning terrestrial ecosystems, the objective was to study organic matter decomposition in soil and other processes related to permanent grasslands.

Biodegradation, Environmental↗
PubMed1999

A role for preadipocytes as macrophage-like cells.

Several lines of evidence have supported a link betweeen adipose tissue and immunocompetent cells. This link is illustrated in obesity, where excess adiposity and impaired immune function have been described in both humans and genetically obese rodents. In addition, numerous factors involved in inflammatory response are secreted by both preadipocytes and macrophages. Here we show that proliferating preadipocytes in cell lines and primary cultures, develop phagocytic activity toward microorganisms. This is demonstrated by phagocytosis assays and confocal microscopy. This function disappears when preadipocytes stop proliferating and differentiate into adipocytes. After phagocytosis, preadipocytes show microbicide activity via an oxygen-dependent mechanism. In addition, preadipocytes as well as adipocytes are stained with MOMA-2, a marker of monocyte-macrophage lineage, but are negative for specific mature macrophage markers (F4/80 and Mac-1). These results suggest that preadipocytes could function as macrophage-like cells and raise the possibility of a potential direct involvement of adipose tissue in inflammatory processes.

Adipocytes↗
PubMed1999

[Prostatic ultrasonography in routine radiological practice: a survey of 122 radiologists].

OBJECTIVE: To evaluate the indications and practical modalities of prostatic ultrasonography in routine radiological practice. METHODS: An anonymous questionnaire composed of 18 multiple choice questions was sent to 122 radiologists. RESULTS: Among the 76 responses, 90% were men, 90% were in private practice and 94% regularly performed prostatic ultrasonography without clinical information (81%). The prostatic examination was performed by transrectal ultrasonography (60%) combined with vesical and renal ultrasonography. The indications were: urinary functional disorders (56%) and abnormal PSA (40%). Prostatic ultrasonography was considered to be useful to calculate prostatic volumes by 59% of radiologists and in the staging of prostatic cancer (81%). 80% of radiologists did not start by performing digital rectal examination. 59% of patients were informed. CONCLUSION: The observed indications did not correspond to urological consensus recommendations, but ultrasonography was performed according to classical recommendations. This study could justify a more precise definition of the role of ultrasonography in prostatic disease.

Adult↗