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Biomedical subjects

P Hubert

Publications and source records attributed to P Hubert.

At least 19 recordsLinked to original sources
PubMed2006

[Premedication before tracheal intubation in French neonatal intensive care units and delivery rooms].

UNLABELLED: Tracheal intubation is a painful procedure commonly used in the neonatal intensive care units and in the delivery rooms. It can be complicated by changes in vital signs. OBJECTIVE: To ascertain the use of sedatives and/or analgesics before tracheal intubation in French neonatal intensive care units and delivery rooms. METHODS: A survey by questionnaire sent to 58 neonatal intensive care units and 58 maternities. RESULTS: We obtained 46 responses (79,3%) from the neonatal intensive care units and 38 (65,5%) from the delivery rooms. In neonatal intensive care units, 74% of the newborns received a sedative and/or an analgesic before being intubated, and 60% of the units had specific written guidelines. Opioïds and benzodiazepines were the main drugs used. In the delivery rooms, sedatives or analgesics were only used in 21% of the centres. CONCLUSION: The use of sedation-analgesia seems to improve in neonatology but is still insufficient in the delivery rooms. The development of specific guidelines and a best learning about the different drugs are necessary.

Analgesics↗
PubMed2006

Risk analysis of leukaemia incidence among people living along the Techa River: a nested case-control study.

Large quantities of radioactive materials released over time from the Mayak nuclear weapons facility caused significant internal and external exposure for people living along the banks of the Techa River (Southern Urals, Russia). We conducted a nested case-control study in the Extended Techa River Cohort to determine whether the risk of leukaemia incidence increased with protracted exposure to ionising radiation or with other non-radiation risk factors. The study included 83 cases identified over 47 years of follow-up and 415 controls matched for sex, age at diagnosis, age (within a 5 year age group), and date of initial residence in the riverside area. External and internal doses have been calculated using the Techa River Dosimetry System 1996 (TRDS96). Conditional logistic regression was used to calculate odds ratios per Gray (OR/Gy) and 95% confidence intervals (95% CI). After excluding cases of chronic lymphoid leukaemia, the OR/Gy of total, external, and internal doses were 4.6 (95% CI: 1.7-12.3), 7.2 (95%CI: 1.7-30.0) and 5.4 (95%CI: 1.1-27.2), respectively. A history of solid tumour, either malignant or benign, before the leukaemia diagnosis was associated with a 2.5-fold increase in the leukaemia risk (95% CI: 1.1-5.9). Even though the analysis of confounders was less useful than expected because of missing data, multivariate analyses that took the exposure dose into account confirmed the association between leukaemia incidence and tumour history.

Case-Control Studies↗
PubMed2006

[Harmonisation of validation strategies and estimation of the associated uncertainty in the framework of assay laboratoires accreditation].

In order to achieve the harmonization of validation strategies, the interpretation of several validation criteria is proposed. Furthermore, a simple and visual decision tool to assess the validity of an analytical procedure is described: the accuracy profile based on the estimation of the total error of the measurements. This profile build with beta-expectation tolerance intervals can also compute with efficiency the uncertainty related to the results of a laboratory, which is an essential parameter for the accreditation of laboratories under ISO 17025.

Accreditation↗
PubMed2006

[The transfer of an automated method for the determination of noradrenaline in human urine: using total error as decision criterion].

Two new statistical approaches based on the total error of measurements were applied to the transfer of an automated method for the determination of noradrenalin in human urine by LC-ECD coupled on-line to SPE. They showed that the receiving laboratory was mastering the analytical procedure allowing it to use the method in routine. Furthermore the risk based approach gave guarantee that the risk to have future measurements out of specification in the receiving laboratory was smaller than 5%, therefore being a risk management tool.

Humans↗
PubMed2006

[Comparison of three approaches for uncertainty estimation].

Three different approaches for the estimation of uncertainty measurements using the same analytical method were compared, namely validation, robustness and inter-laboratory studies. The uncertainty obtained with the robustness study! predicted well the uncertainty of the inter-laboratory study. On the other hand, the uncertainty estimation obtained with the validation study is lower than those obtained with the two other approaches but is still acceptable as long as the analytical method will be used in a single laboratory.

Chromatography, Liquid↗
PubMed2005

[Withholding or withdrawing life saving treatment in pediatric intensive care unit: GFRUP guidelines].

Several recent French studies have revealed that 40% of death in pediatric intensive care units are associated with withdrawal or limitation of life saving treatments. Because such decisions are common, the Groupe francophone de réanimation et urgences pédiatriques (GFRUP) has decided to publish recommendations in order to help paediatricians dealing with those difficult issues and to improve their decisions. In a first part of the document the ethical principles that imply those guidelines are recalled, followed by definitions of the terms currently employed. The second part contains guidelines regarding decision making process, the way it is applied and organisation of relatives as well as paramedical and medical staff support when the death of a child occurs.

Child↗
PubMed2005

Inhibition by transmembrane peptides of chimeric insulin receptors.

Receptor tyrosine kinases play essential roles in cell proliferation and differentiation. We have recently shown that peptides corresponding to the transmembrane domains of the epidermal growth factor (EGF) and ErbB2 receptors inhibit their corresponding receptor activation in cancer cell lines. We extend this observation to cells transfected with chimeric insulin receptors where the transmembrane domain has been replaced by that of the EGF receptor or a mutated Erb2 domain. Peptides corresponding to the transmembrane domains of the EGF receptor and ErbB2 are able to inhibit specifically the autophosphorylation of insulin receptors with the corresponding domain. This inhibitory effect is correlated with the propensity of the different transmembrane domains to self-associate in a genetic reporter assay. Thus, our data strengthen the notion that transmembrane domains are involved in erbB receptor activation, and that these receptors can be modulated by inhibiting protein-protein interactions within the membrane.

Amino Acid Sequence↗
PubMed2005

The effect of alginate, hyaluronate and hyaluronate derivatives biomaterials on synthesis of non-articular chondrocyte extracellular matrix.

Cartilage engineering consists of re-constructing functional cartilage by seeding chondrocytes in suitable biomaterials in vitro. The characteristics of neocartilage differ upon the type of biomaterial chosen. This study aims at determining the appropriate scaffold material for articular cartilage reconstruction using non articular chondrocytes harvested from rat sternum. For this purpose, the use of polysaccharide hydrogels such as alginate (AA) and hyaluronic acid (HA) was investigated. Several ratios of AA/HA were used as well as three derivatives obtained by chemical modification of HA (HA-C18, HA-C12(2.3), HA-C12(2.5)-TEG0.5). Sternal chondrocytes were successfully cultured in 3D alginate and alginate/HA scaffolds. HA retention in alginate beads was found to be higher in beads seeded with cells than in beads without cells. HA-C18 improved HA retention in beads but inhibited the chondrocyte synthesis process. Cell proliferation and metabolism were enhanced in all biomaterials when beads were mechanically agitated. Preliminary results have shown that the chondrocyte neo-synthesised matrix had acquired articular characteristics after 21 days culture.

Alginates↗
PubMed2005

Delayed surgery in pericardial teratoma with neonatal hydrops.

Timing of neonatal surgery in cases of pericardial teratoma with hydrops is not standardised. We report two cases of hydropic premature newborns with pericardial teratoma in which surgery was delayed until respiratory and haemodynamic stabilisation. Mature teratoma was removed on day 3. The newborns were weaned from the ventilator on postoperative day 5 and 10, respectively. Both infants were doing well at 18 months, suggesting delayed surgery may be feasible and effective.

Adult↗
PubMed2005

Minimum effective dose of midazolam for sedation of mechanically ventilated neonates.

OBJECTIVE: To determine the minimal effective dose (MED) of intravenous midazolam, required for appropriate sedation in 95% of patients, 1 h after drug administration. METHODS: A double-blind dose-finding study using the continual reassessment method, a Bayesian sequential design. Twenty-three newborn infants hospitalized in intensive care unit participated. Inclusion criteria were: (i) post-natal age <28 days, (ii) gestational age >33 weeks, (iii) intubation and ventilatory support required for respiratory distress syndrome, (iv) need for sedation (i.e. one of the six following criteria: agitation or grimacing or crying facial expression before tracheal suctioning, agitation or grimacing or crying facial expression during tracheal suctioning). Each neonate was allocated to a loading dose, ranging from 75 to 200 microg/kg, and a maintenance dose ranging from 37.5 to 100 microg/kg/h. RESULTS: The primary endpoint was the level of sedation 1 h after the onset of infusion. The sedation procedure was classified as a success if all the following clinical criteria were met: no agitation, no grimacing and no crying facial expression before as well as during tracheal suctioning. Based on the 23 patients, the final estimated probability of success was 76.9% (95% credibility interval: 56.6-91.4%) for the 200 microg/kg loading dose. no significant adverse effect was observed. CONCLUSIONS: Continual reassessment is a new approach, suitable for dose-finding study in neonates. this method overcomes some of the ethical, statistical and practical problems associated with this population. Using this method, the MED was estimated to be the 200 mug/kg loading dose of midazolam.

Dose-Response Relationship, Drug↗
PubMed2004

Hydrophobically modified alginate hydrogels as protein carriers with specific controlled release properties.

Amphiphilic derivatives of sodium alginate, prepared by chemical covalent binding of long alkyl chains onto the polysaccharide backbone via ester functions, form strong hydrogels in aqueous solutions. The shear-thinning and thixotropic behaviors of these hydrogels have been exploited to prepare particles (millimetric beads or microparticles) by dispersion in sodium chloride solutions. This all-aqueous procedure was used for the encapsulation of model proteins, such as bovine serum albumin (BSA) and human hemoglobin (Hb), or of a vaccine protein (Helicobacter pylori (H. pylori) urease). In all cases, the encapsulation yields were very high (70-100%). No release of model proteins was observed in water within several days, in contrast with protein-loaded calcium alginate particles, which exhibit an important release within only a few hours. The controlled release of proteins can, however, be achieved by inducing the dissociation of the physical hydrophobic network. This dissociation has been obtained either by addition of surfactants, acting as disrupting agents of intermolecular hydrophobic junctions, or of esterases such as lipases, which hydrolyze the ester bond between alkyl chains and the polysaccharide backbone. The level of immunization against H. pylori infection in mice, induced by encapsulated urease administrated by either systemic or mucosal routes, was also assessed.

Alginates↗
PubMed2004

Physical alginate hydrogels based on hydrophobic or dual hydrophobic/ionic interactions: bead formation, structure, and stability.

Hydrophobically associating alginate (AA) derivatives were prepared by covalent fixation of dodecyl or octadecyl chains onto the polysaccharide backbone (AA-C12/AA-C18). In semidilute solution, intermolecular hydrophobic interactions result in the formation of physical hydrogels, the physicochemical properties of which can be controlled through polymer concentration, hydrophobic chain content, and nonchaotropic salts such as sodium chloride. The mechanical properties of these hydrogels can then be reinforced by the addition of calcium chloride. The combination of both calcium bridges and intermolecular hydrophobic interactions leads to a decrease in the swelling ratio accompanied by an increase of elastic and viscous moduli. Beads made of hydrophobically modified alginate were obtained by dropping an aqueous solution of alginate derivative into a NaCl/CaCl2 solution. As compared to unmodified alginate beads, modified alginate particles proved to be stable in the presence of nongelling cations or calcium-sequestering agents. However, evidence is presented for a more heterogeneous structure than that of plain calcium alginate hydrogels with, in particular, an increase in the effective gel mesh size, as determined by partition and diffusion coefficient measurements.

Journal Article↗
PubMed2004

Production of microspheres based on hydrophobically associating alginate derivatives by dispersion/gelation in aqueous sodium chloride solutions.

A new "all aqueous" procedure for the preparation of stable polysaccharide microparticles was developed. The method consists of dispersing a water solution of an amphiphilic alginate derivative (in the current work, alginate substituted with low amounts of dodecyl chains) first fluidified under mechanical stress, into an NaCl solution. The procedure exploits the ability of amphiphilic associative derivatives to form strong hydrogels in the presence of nonchaotropic salts and their shear-thinning/thixotropic properties. Depending on the experimental conditions, the size of the microparticles can be varied from 10 microm to several hundred micrometers. Their mechanical properties can eventually be reinforced by addition of low concentrations of calcium chloride. The resulting microparticles exhibit a better stability than that of plain Ca(2+)-alginate particles, as they are not disrupted when nongelling cations or calcium-sequestering agents are added to the solution. In addition, the particles can be easily redispersed after being centrifuged or freeze-dried.

Alginates↗
PubMed2004

Cancer mortality among French Atomic Energy Commission workers.

BACKGROUND: All causes and cancer mortality of 58,320 workers employed at the Commissariat à l'Energie Atomique (CEA) between 1946 and 1994 were compared with that of the general population in a retrospective cohort study. METHODS: Standardized Mortality Ratios (SMR) were computed with reference to the French national population. RESULTS: Between 1968 and 1994, 4,809 deaths occurred. A healthy worker effect is observed for men (SMR = 0.57, CI(90%) = [0.56;0.59]) and for women (SMR = 0.72, CI(90%) = [0.67;0.77]). Nine sites of cancer death were found to be in statistically significant deficit among men, none among women. An excess of pleural cancers is observed among men (SMR = 1.79, CI(90%) = [1.27;2.45]) and of malignant melanoma (SMR = 1.50, CI(90%) = [1.04;2.11]). An excess of breast cancer is observed among women on the borderline of significance (SMR = 1.14, CI(90%) = [0.94;1.37]). CONCLUSIONS: Excesses observed will have to be related to occupational exposures in the on-going cohort study on French nuclear workers which includes a retrospective exposures assessment.

Adult↗