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Biomedical subjects

M Leroy

Publications and source records attributed to M Leroy.

At least 19 recordsLinked to original sources
PubMed2005

Expression of the interferon-alpha/beta-inducible bovine Mx1 dynamin interferes with replication of rabies virus.

Rabies is a fatal anthropozoonotic viral infection of the central nervous system that remains a serious public health problem in many countries. As several animal cases of spontaneous survival to infection were reported and because type 1 interferons were shown to protect against the virus, it was suggested that innate resistance mechanisms exist. Among the antiviral proteins that are synthesized in response to interferon-alpha/beta stimulation, Mx proteins from several species are long known to block the replication of vesicular stomatitis virus (VSV). As both VSV and rabies virus belongs to the Rhabdoviridae family, this study was started with the aim to establish whether the anti-VSV activity of a mammalian Mx protein could be extended to rabies virus. This question was addressed by inoculating the virus onto a bovine Mx1 or human MxA-expressing Vero cell clone. Plaque formation was unambiguously blocked, and viral yields were reduced 100- to 1000-fold by bovine Mx1 expression for both SAG2 and SADB19 viral strains. In opposition, only SAG2 strain could be inhibited by the expression of human MxA protein. The effect of both proteins expression was then evaluated at the viral protein expression level. Again, boMx1 was able to repress protein expression in both strain, whereas only SAG2 proteins were inhibited in human MxA-expressing cells. These results suggest that protection conferred by interferon-alpha/beta against rabies could be, at least partially, attributable to the Mx pathway. Alternatively, bovine Mx1 could be unique in its ability to repress rabies virus which, if confirmed in vivo, would open an avenue for the development of new antirabies therapeutic strategies.

Animals↗
PubMed2005

[Compliance with and acceptability of a new electronic peak flow meter, the PiKo-1].

BACKGROUND: Monitoring airflow obstruction is an essential component of asthma management. We examined home recording of PEFR using a new electronic peak flow meter in terms of compliance and acceptability in a group of children with asthma. METHODS: Twenty three children (3 with intermittent asthma and 20 with persistent asthma) (average age 10.9 +/- 3.8 [5-18] yrs) were asked to assess their PEFR every day during a period of 5.8 +/- 1.2 [4-8] weeks and record it in a diary card. Patients were not aware that their data was also being stored on the PiKo-1. At the end of the study, the written data were compared to the stored data. A multiple choice questionnaire was given to each subjectto check the acceptability of the PiKo-1. RESULTS: 2 patients were lost to follow up. The compliance (expressed as a percent of the number of recordings that should have been made) was more that 80% for 14/21(67%) patients and less than 45% for 3/21 (14%). Compliance decreased during the study (96% in the first week, 68% during the fifth). 12% of the values were falsified. The PiKo-1 was considered to be small, attractive and useful. Some children found the mouthpiece too small. CONCLUSION: The good results for compliance that we observed might have been due to the short duration of the study. PiKo-1 was well accepted by the subjects. It will be possible to monitor PEFR and forced expiratory volume in the first second of expiration at home using this new device.

Adolescent↗
PubMed2003

Degradation of organolead species in aqueous solutions by electron beam irradiation.

Electron beam irradiation of aqueous solutions containing different lead compounds (Pb(2+), (CH(3))(3)Pb(+), (C(2)H(5))(3)Pb(+)) was carried out. Formate and hydrogen peroxide were used as radical scavengers to elucidate the influence of the different species generated by water radiolysis. The precipitation of Pb(2+), only observed in the presence of formate, was attributed to COO(*-) but the nature of the precipitate is still unclear. Organolead compounds were shown to be efficiently degraded, probably converted into Pb(2+), using doses around 4 kGy. In the absence of scavengers, the degradation occurred according to the alkyl group stability. Both trialkyllead compounds were shown to be degraded by HO(*). On the contrary, the contribution of hydrogen atoms (H(*)) was shown to be highly dependent on the nature of the alkyl group, i.e. negligible for (C(2)H(5))(3)Pb(+) and more important for (CH(3))(3)Pb(+).

Chemical Precipitation↗
PubMed2002

Hypercapnia during transperitoneal and retroperitoneal endoscopic spinal surgery: a prospective study.

STUDY OBJECTIVE: To evaluate the effect of carbon dioxide (CO(2)) pneumoperitoneum and retropneumoperitoneum insufflation on CO(2) excretion. DESIGN: Prospective study. SETTING: Operating room and recovery room in a teaching hospital. PATIENTS: 29 patients scheduled for orthopedic spine fusion surgery. INTERVENTIONS: Patients received either transperitoneal insufflation (n = 12) or retroperitoneal insufflation (n = 17). MEASUREMENTS AND MAIN RESULTS: Increases in the partial pressure of end-tidal CO(2) (PetCO(2)) and arterial CO(2) tension (PaCO(2)) during retropneumoperitoneum exceeded those obtained during pneumoperitoneum. Furthermore, PetCO(2) increased faster during retroperitoneum and did not reach a plateau. Finally, 76% of the patients in this group required ventilatory adjustment due to high PetCO(2) levels. CONCLUSIONS: This study may focus attention on the need for continuous ventilatory adjustments during transperitoneal endoscopic surgery.

Acidosis, Respiratory↗
PubMed2002

[Contribution of ovarian and uterine color Doppler in medically assisted reproduction techniques (ART)].

Along the menstrual cycle and during pregnancy, small blood vessels proliferate within the uterus and the ovulating ovary. Angiogenic factors such as VEGF are involved in this phenomenon. In the ovulating ovary, neo-angiogenesis spreads progressively inside the dominant follicle wall and plays a role in the maintenance of the corpus luteum, under the influence of LH (or HCG during pregnancy). In ART, the measure of the blood flow is interesting since it correlates to the number and quality of harvested oocytes. Follicle hypoxia may impair chromosomal organization and separation within the oocyte. This neo-angiogenesis is also important in endometrium, in particular for embryo implantation. Ultrasounds with Doppler allow to estimate the endometrial receptivity, especially in IVF cycles. It is assumed that chance for ongoing pregnancy is almost zero if: endometrial thickness is < 8 mm; uterine pulsatility index (PI) is > 3. Doppler ultrasounds are a useful and even mandatory complement to standard vaginal ultrasonoghraphy in ART. It can be viewed as an indicator of the endometrial and follicular "well-being".

Endometrium↗
PubMed2002

Exacerbation of sleep-apnoea related nocturnal blood-pressure fluctuations in hypertensive subjects.

Obstructive sleep apnoea syndrome (OSAS) induces marked haemodynamic fluctuations during sleep that might be deleterious to the cardiovascular system. The influence of daytime blood pressure (BP) levels and aging on short-term BP variability during sleep in OSAS patients was investigated. Twenty-nine subjects with newly-diagnosed untreated OSAS were categorised into three groups: normotensive subjects aged <50 yrs (n=10); subjects aged <50 yrs with untreated hypertension (n=8); and normotensive subjects aged >50 yrs (n=11). Beat-by-beat BP was recorded with a Finapres device during polysomnography. The average values+/-SD of apnoea-related BP elevations and the values of the frequency distribution of all BP variations during sleep were assessed to estimate short-term BP variability. Apnoea-related systolic (or diastolic) BP elevations were significantly greater in hypertensives than in normotensives aged <50 yrs (50.3+/-4.88 versus 30.7+/-2.14 mmHg, p<0.001), as was the SD of systolic (or diastolic) BP variations during sleep (19.6+/-2.22 versus 11.1+/-0.73, p<0.001). Short-term BP variability was not significantly increased in normotensive elderly patients. To conclude, the results suggested that systemic hypertension is associated with a greater exacerbation of short-term variability during sleep in obstructive sleep apnoea syndrome patients.

Adult↗
PubMed2001

Arterial blood gases during exercise: validity of transcutaneous measurements.

OBJECTIVE: To investigate the validity of transcutaneous measurements of blood gas tensions for the assessment of partial arterial pressure of oxygen (PaO(2)) and carbon dioxide (PaCO(2)) during treadmill exercise. DESIGN: Experimental, self-controlled against a reference standard. SETTING: Lung function laboratory. PATIENTS: Eighty-one patients with various lung diseases. INTERVENTIONS: At rest and at symptom-limited peak exercise, puncture of the radial artery with concurrent transcutaneous measures of blood gases. MAIN OUTCOME MEASURES: Arterial blood samples were analyzed with a radiometer to measure PaO(2) and PaCO(2). A microgas apparatus was used to measure gas tensions transcutaneously. Values obtained transcutaneously (TcPO(2), TcPCO(2)) were compared with those obtained by blood sample. TcPO(2) was adjusted as close as possible to the PaO(2) obtained in the same conditions, with the correction factor of the apparatus. Values obtained transcutaneously were compared with those obtained by blood sample to establish the sensitivity and specificity of the noninvasive method. RESULTS: Mean differences +/- standard deviation between transcutaneous and arterial tension at peak exercise were 0.4 +/- 7.0mmHg and 2.1 +/- 3.3mmHg for PaO(2) and PaCO(2), respectively. The transcutaneous device enabled us to predict a decrease in PaO(2) (>or=2mmHg) from rest to exercise with a sensitivity of 92.1% and a specificity of 90% and an increase in PaCO(2) with a sensitivity of 88% and a specificity of 58.9%. CONCLUSIONS: Although transcutaneous measurement are sufficiently sensitive and specific to detect patients whose PaO(2) decreases during exercise, its precision is not sufficient for gas exchange calculations.

Adolescent↗
PubMed2001

Determination of tumor markers in serum. Pitfalls and good practice.

The determination of tumor markers may have consequences for the patients' treatment, which requires special attention to the analysis and to the expression of the results. In addition to the factors usually dealt with in the pre-analytical phase (identification, quality and storage of the sample) and in the analytical phase (interference, endogenous antibodies, hook effect), we must consider factors such as normal values (which depend heavily on the used techniques), threshold values defining other characteristics (sensitivity, specificity, positive and negative predictive value) and kinetics. Knowledge of the limitations of the tumor marker analysis, in particular tumor markers for non-cancerous diseases leading to possible increases (false positives), is also indispensable. All of this led to the definition of guidelines for good practice, including the design of quality control, rules for requesting, validation and interpretation of results, and the setting up of a serum library.

Antibodies↗
PubMed2000

Increased hyaluronan and hyaluronidase production and hyaluronan degradation in injured aorta of insulin-resistant rats.

Diabetic patients have a greater incidence of restenosis, which has been shown to be related to exaggerated intimal hyperplasia. Hyaluronan (HA) has been shown to be closely involved in arterial smooth muscle cell proliferation and migration, which provoke intimal hyperplasia after balloon catheter injury. Our aim was to determine the effect of fructose feeding, which produces certain characteristics of non-insulin-dependent diabetes (ie, insulin resistance, hyperinsulinemia, and hypertriglyceridemia), on production of HA and hyaluronidase and degradation of HA in rat aorta. Treated rats received fructose (25% in tap water) 12 weeks before balloon catheter injury and 14 days afterward. Fructose-fed rats had hyperinsulinemia and hypertriglyceridemia. Injury increased intima-media wet weight (7.5%) and DNA content (20%) in control rats. This increase was significantly greater in fructose-fed rats (22% for wet weight and 34% for DNA content) and was associated with greater HA and hyaluronidase production (123% and 41%, respectively) than in control rats (49% and 7%, respectively). Determination of HA molecular mass showed that balloon catheter injury increased the number of HA fragments in the aorta of control rats. Normal aorta of fructose-fed rats contained more HA fragments than that of control rats. Injury to the aorta of fructose-fed rats increased HA fragments and induced the appearance of a very-high-molecular-mass (>2000 kDa) HA. In conclusion, fructose treatment, which induced hyperinsulinemia and hypertriglyceridemia, increased HA and hyaluronidase production and HA degradation in injured aorta. This finding suggests that HA, which has been shown to play a crucial role in proliferation and migration of arterial smooth muscle cells, may be involved in the promotional effect of long-term fructose feeding on arterial wall reaction to injury.

Animals↗
PubMed1999

Effect of celiprolol treatment in hypertensive patients with sleep apnea.

The effects of a beta-blocker, celiprolol, on sleep and arterial blood pressure (BP) were evaluated during a single-blind study in seven hypertensive patients with sleep apnea. Diurnal ambulatory BP measurements with an automatic cuff-inflation device and polysomnography with simultaneous Finapres BP recording were performed separately on consecutive days at the end of two 21-day treatment periods involving placebo followed by celiprolol (200 mg/day). Age was 59 +/- 2.5 yr (m +/- sem) and body mass index 33.2 +/- 2.3 kg. m-2. Diurnal ambulatory BP was significantly lower with celiprolol than with placebo (systolic 139 +/- 4 vs 152 +/- 5 mmHg, diastolic 86 +/- 2 vs 96 +/- 2 mmHg). The apnea-hypopnea index was similar under celiprolol and placebo (48 +/- 7.4 vs 53 +/- 7.8, respectively), as were the total sleep time and percent of duration of the different sleep stages. Individual average BP values were significantly lower during REM sleep under celiprolol but remained similar under celiprolol and placebo in the other sleep stages. Variability of nocturnal BP (assessed by the SD of distribution of BP variations) was not affected by celiprolol. In conclusion, celiprolol which decreased daytime BP, did not affect sleep pattern or respiratory disturbances, or nocturnal BP variability related to apnea.

Aged↗
PubMed1999

Oxidation of arsenite to arsenate by a bacterium isolated from an aquatic environment.

Arsenic is ubiquitous in the biosphere and frequently reported to be an environmental pollutant. Global cycling of arsenic is affected by microorganisms. This paper describes a new bacterial strain which is able to efficiently oxidize arsenite (As[III]) into arsenate (As[V]) in liquid medium. The rate of the transformation depends on the cell density. Arsenic species were separated by high performance liquid chromatography (HPLC) and quantified by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The strain also exhibits high minimum inhibitory concentrations (MICs) for As[III] (6.65 mM (500 mg L-1)) and other heavy metals, such as cadmium (1.42 mM (160 mg L-1)) or lead (1.20 mM (250 mg L-1)). Partial identification of the strain revealed a chemoorganotrophic, Gram-negative and motile rod. The results presented here demonstrate that this strain could represent a good candidate for arsenic remediation in heavily polluted sites.

Arsenates↗
PubMed1999

[Importance of the chemical composition and chromatographic resins since the scaling up of a procedure for the purification of proteins].

Despite having the same ionic character, ion exchangers for protein separation are not identical to each other hence differences in results are generally anticipated when scaling up operations from laboratory to production. This is illustrated by comparative studies presented in this article which shows the separation of an IgG-rich fraction from sweet whey using Q-resins. One resin, available in three different particle sizes for scale changes to avoid high back pressure when increasing the size of the column, was compared with a resin that does not have the corresponding larger size particles so that scale changes have to be performed using another chemically different sorbent. Investigation of dynamic binding capacity, resolution versus loading and scale changes, demonstrated the importance of maintaining consistency in the chemical composition for an ion exchanger to eliminate differences in separation properties and therefore reduce the process development time required for specific optimization of separation conditions and maximizing productivity.

Chromatography, Ion Exchange↗
PubMed1998

Effect of aging on neointima formation and hyaluronan, hyaluronidase and hyaluronectin production in injured rat aorta.

Few studies have examined the effect of aging on arterial wall response to injury, and the results are discordant. Moreover, the effect of aging on hyaluronan synthesis in injured vessels is unknown. The aim of this present study was to determine the effect of aging on neointima formation and hyaluronan (HA), hyaluronidase and hyaluronectin production in injured rat aorta. Aorta was analysed in sham-operated rats (group D0) and 14 (D14) and 28 (D28) days after injury using biochemical and immunohistochemical techniques. Uninjured aorta of old rats was more thickened than that of young rats; it showed a decreased number of arterial smooth muscle cells (ASMC) and was characterized by HA accumulation in the intima and increased hyaluronidase activity. Intima-media wet weight was significantly increased in young rats at D14 and D28 but remained unchanged in old rats. DNA content was significantly enhanced at D14 in both young and old rats. DNA decreased slightly in young rats at D28 but significantly in old rats to return to control level. HA content and hyaluronidase activity in the intima-media were markedly increased in young rats at D14 (+148% and +116% respectively) but slightly in old rats (+23% and +15% respectively). Both HA and hyaluronidase activity continued to increase at D28, but remained more produced in young rats. The immunohistochemical analysis showed the formation of a thickened neointima in young rats, which was associated with strong expression of HA and HN. Neointima of old rats was reduced; it also showed strong expression of HA and HN but their distributions were different from those observed in neointima of young rats. In conclusion, aorta of old rats showed an increased amount of HA in the intima and elevated activity of hyaluronidase. Injury induced formation of a significant neointima in young rats but not in old rats. This was correlated with more HA and hyaluronidase production in injured aorta of young rats. As HA is considered to increase extracellular matrix space and to promote ASMC proliferation and migration, our findings suggest that HA may be implicated in intima thickening with age and after injury.

Aging↗
PubMed1998

[Tracheal resection-anastomosis for iatrogenic stenosis. Experience in 340 cases].

Since 1975, 340 patients were treated by tracheal sleeve resection for tracheal or subglottic laryngeal iatrogenic stenoses in our unit. Preoperative iterative Nd YAG laser sessions have usually been performed, without success. The length of the sleeve specimen was an average of 3 1/4 cm. Twelve patients died on the post operative course (3.5%), 3 more patients died later after failure of the procedure (0.9%) and nineteen had recurrent stenoses treated with use of a tracheostomy tube, a permanent Montgomery tube, or an endotracheal stent (5.6%). Three hundred and six patients are definitely cured (90%), at the first attempt for 265 patients, after a laser session for granulomas for 20 patients, after a second tracheal resection for 6 patients and after a temporary Montgomery tube for 15 patients. Providing there is a good selection of the patients, tracheal sleeve resection is the best treatment for iatrogenic stenosis.

Adolescent↗
PubMed1998

[Reduction of native lung volume after single-lung transplantation for emphysema].

We report three cases of volume reduction surgery in three single lung transplant recipients with emphysema. Each patient had a late decline in lung function with hyper-inflation of the native lung. Lung function was improved post-operatively for two patients. The relief of thoracic overdistension may be considered in single lung transplant recipients who exhibit clinical significant functional deterioration.

Adult↗
PubMed1997

Dynamic compaction: a new process to compact therapeutic agent-loaded calcium phosphates.

The sintering stage in the classical process of preparing bone substitution materials prevents therapeutic agents from being loaded into calcium phosphate powder. However, dynamic compaction, a new process, requires no external heat, allowing the therapeutic agent to be incorporated into ceramics. This report presents the results of an in vitro study of therapeutic agents associated with calcium phosphate powder and involving this new process. A mixture of vancomycin lyophilized powder (0.15 g) and biphasic calcium phosphate (BCP) powder (1.85 g) was compacted. In addition, 2 ml of human growth hormone (1 mg ml-1) were associated with BCP powder by physical adsorption on bead surfaces before compaction. Detection by monoclonal antibodies and sodium dodecyl sulphate polyacrylamide gel electrophoresis demonstrated the structural integrity of the two therapeutic agents after consolidation. This new compaction process should be useful in developing ceramics that contain a therapeutic agent.

Adsorption↗