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Biomedical subjects

C Charpentier

Publications and source records attributed to C Charpentier.

At least 19 recordsLinked to original sources
PubMed2006

[Cerebral microdialysis as a clinical tool].

Microdialysis is the only technique available for cerebral metabolic monitoring in the clinical setting. By the mean of a probe inserted in the brain, it provides an extracellular space sampling. Values of various substrates including cerebral glucose, lactate, pyruvate, glycerol or glutamate can be obtained at the bedside at intervals between minutes and hours. Values are critically dependent on the flow of the perfusion liquid and reflect a highly localized cerebral metabolism. Cerebral microdialysis improves our understanding of acute neurological events such as intracranial hypertension or decrease in brain tissue oxygen pressure. Cerebral microdialysis can be used for detection of ischaemia, especially after malignant stroke or vasospasm complicating subarachnoid haemorrhage. In these cases, it may influence the therapeutic management. Moreover, it permits the assessment of metabolic changes after therapeutic interventions. Finally, some markers (like lactate/pyruvate ratio) are related to outcome, especially after traumatic brain injury.

Animals↗
PubMed2005

Liposuction and extravasation injuries in ICU.

Liposuction is a minimally invasive surgical technique, occasionally used to minimize the risk of devastating soft tissue necrosis following extravasation of noxious substances. Anaesthetists and intensive care physicians frequently use agents that may cause serious tissue injury if extravasated. Therefore, knowledge on how to manage this complication is important. We present two cases of percutaneous extravasation of noxious agents in intensive care patients and discuss their subsequent management.

Adolescent↗
PubMed2005

[Anaesthetic management of the patient with acute intracranial hypertension].

Transcranial Doppler and, if possible, measurement of intracranial pressure (ICP) allow preoperative diagnosis of acute intracranial hypertension (ICH) after brain trauma. The main goal of the anaesthesiologist is to prevent the occurrence of secondary brain injuries and to avoid cerebral ischaemia. Treatment of high ICP is mainly achieved with osmotherapy. High-dose mannitol administration (1.4 to 2 g/kg given in bolus doses) may be considered a better option than conventional doses, especially before emergency evacuation of a cerebral mass lesion. Hypertonic saline seems as effective as mannitol without rebound effect and without diuresis increase. Haemostasis should be normalized before neurosurgery and invasive blood pressure monitoring is mandatory. For anaesthesia induction, thiopental or etomidate may be used. In case of ICH, halogenated and nitrous oxide should be avoided. Until the dura is open, mean arterial pressure should be maintained around 90 mmHg (or cerebral perfusion pressure around 70 mmHg). If a long-lasting (several hours) extracranial surgery is necessary, ICP should be monitored and treatment of ICH should have been instituted before.

Acute Disease↗
PubMed2004

Release of macromolecules by Saccharomyces cerevisiae during ageing of French flor sherry wine "Vin jaune".

The French flor sherry wine "Vin jaune" spends 6 years and 3 months in the same barrel under a yeast velum. Because of temperature variations in the cellars, this velum sinks partially into the wine and a deposit of dead yeasts cells accumulates in the bottom of the barrels, favouring the formation of new velum. Growth and autolysis occur simultaneously. This study investigated the evolution of macromolecules released by yeasts during the ageing of "Vin jaune" in a model system closely simulating winemaking. It was observed that the release of macromolecules during the formation of the velums by living yeasts was low but greatly increased when the velums fell and yeast viability decreased. The release of macromolecules was then due to the autolysis of dead cells. Analysis of macromolecules during ageing revealed that they contained 73.3-78.5% neutral sugars and 6-7% proteins according to the ageing stage. Their amino acid composition did not change during ageing. A high content of serine and threonine commonly involved in O-glycosidic linkages present in yeast mannoproteins was observed. Throughout ageing, the mannose and glucose contents of macromolecules increased but the ratio of polymeric mannose to glucose decreased. Size exclusion chromatography showed that mannoproteins released in wine were partially hydrolysed by yeast beta-1,3-glucanases freed in wine.

Bacteriolysis↗
PubMed2003

[Analysis of the criteria that contribute to the decision to harvest the heart in brain-dead organ donors].

OBJECTIVES: The number of cardiac transplantation procedures does not increase because of the lack of donor hearts despite an increase in the number of brain-dead organ donors. The criteria used to select a donor heart are not formally standardized. The aim of the present study was to analyze the criteria that contribute to the selection of a donor heart. TYPE OF STUDY: Descriptive, retrospective study. PATIENTS AND METHOD: Clinical parameters, the initial causes that lead to brain death, maximum doses of catecholamines, several biochemical markers of myocardial ischaemia/necrosis as well as several echocardiography criteria were extracted from a prospectively collected database. Univariate and multivariate (logistic regression) analyses were performed with the "harvested heart" as dependent variable and the above-cited independent variables. RESULTS: One hundred and eighty consecutive brain-dead patients admitted from 1st October 1998 to 31st December 2000 out of which 112 gave at least one organ were analyzed. Among these 112 patients, 59 (39 males and 20 females) were pre-selected as potential heart donors. Only 44 hearts were harvested. Logistic regression analysis showed that harvesting of the heart was more probable if the donor were a male, had no left ventricle systolic wall motion abnormalities, had low doses of norepinephrine and low serum troponin Ic concentrations. CONCLUSION: After an initial phase of selection, the final decision to harvest a heart is based on several criteria. These results should be an incentive to conceive a score that could allow a more formal decision process for heart harvesting.

Adolescent↗
PubMed2002

Yeast adapted to wine: nitrogen compounds released during induced autolysis in a model wine.

As important as the blend of base wines before bottling, one of the most important steps in the champagne-making process is the long ageing on lees. Two yeast strains of Saccharomyces cerevisiae MC001 and MC002, used in champagne wine production, were allowed to autolyse. After 8 days of autolysis, active dry yeasts adapted to wine released 1.7- to 1.8-fold more nitrogen compounds than nonadapted active dry yeast. The nitrogen content (total, proteins, peptides and amino) present in autolysates was measured for yeasts adapted to wine. The composition of free amino acids and amino acids constituting peptides showed no difference between the two strains of yeast used. Studies of intracellular proteolytic activity and release of peptides showed no correlation between these two phenomena. These results indicate that yeasts adapted to wine give results similar to those that occur in wine during ageing.

Amino Acids↗
PubMed2001

Characterisation of the yeast Pichia membranifaciens and its possible use in the biological control of Botrytis cinerea, causing the grey mould disease of grapevine.

Pichia membranifaciens strain FY-101, isolated from grape skins, was found to be antagonistic to Botrytis cinerea, the causal organism of the grey mould disease of the grapevine. When grown together on solid as well as liquid media, the yeast brings about the inhibition of this parasitic fungus, coagulation and leakage of its cytoplasm, and suppression of its ability to produce the characteristic grey mould symptoms on the grapevine plantlets. In vitro experiments confirm that this yeast can be used as a biological control organism against B. cinerea. An account of the molecular characterisation of P. membranifaciens (complete sequence of the ITS region of its ribosomal DNA, GenBank accession No. AF 270935), as well as the interaction between B. cinerea and the yeast, are given here.

Antibiosis↗
PubMed2001

Purification method for the isolation of monophosphate nucleotides from Champagne wine and their identification by mass spectrometry.

Monophosphate nucleotides are difficult to identify in Champagne wine because they are present in small concentrations in a complex mixture. A method for the isolation, separation and identification of reference compounds, which achieved on average 79% recovery (except for cytidine derivatives), was developed and applied to wine. Some monophosphate nucleotides were then isolated from a Champagne wine aged on lees for 8 years, by ultrafiltration followed by a semi-preparative HPLC step using a strong anion-exchange column. The fraction obtained was subjected to HPLC in a reversed-phase column to remove the salt previously introduced, before identification of compounds by HPLC coupled to a mass spectrometer. For the first time in wine, 5'-IMP, 5'-AMP, 5'-CMP, 5'-GMP, 5'-UMP and the 3'- and/or 2'-isomers of the four latter compounds were identified by comparing their HPLC and electrospray ionization mass spectrometry data with those of reference nucleotides.

Chromatography, High Pressure Liquid↗
PubMed2001

Aroma compound sorption by oak wood in a model wine.

Oak wood used for wine barrels was immersed into a model wine containing eight aroma compounds (e.g., aromatic and terpene alcohols, ethyl esters, and aldehyde), for which activity coefficients in water and model wine were determined using the mutual solubility measurement. A mass balance of these volatiles considering their reactivity in model wine was established. For most of the studied aroma compounds, and mainly for linalool and ethyl octanoate, a sorption behavior into wood was reported for the first time. This phenomenon was selective and could not be related to the solubilities in model wine and hydrophobicities of the studied aroma compounds, suggesting that acid-base and polar characteristics of wood were more involved in this sorption mechanism. This study has also shown that the level of sorption is a function of the ratio of wood surface area/solution volume.

Food Handling↗
PubMed2001

Protease A activity and nitrogen fractions released during alcoholic fermentation and autolysis in enological conditions.

Determination of protease A activity during alcoholic fermentation of a synthetic must (pH 3.5 at 25 degrees C) and during autolysis showed that a sixfold induction of protease A activity occurred after sugar exhaustion, well before 100% cell death occurred. A decrease in protease A activity was observed when yeast cell autolysis started. Extracellular protease A activity was detected late in the autolysis process, which suggests that protease A is not easily released. Evolution of amino acids and peptides was determined during alcoholic fermentation and during autolysis. Amino acids were released in early stationary phase. These amino acids were subsequently assimilated during the fermentation. The same pattern was observed for peptides; this has never been reported previously. During autolysis, the concentration of amino acids and peptides increased to reach a maximum of 20 and 40 mg N l(-1), respectively. This study supports the idea that although protease A activity seemed to be responsible for peptides release, there is no clear correlation among protease A activity, cell death, and autolysis. The amino acid composition of the peptides showed some variations between peptides released during alcoholic fermentation and during autolysis. Depending on aging time on yeast lees, the nature of the peptides present in the medium changed, which could lead to different organoleptic properties.

Alcohols↗
PubMed2001

Outcome of COPD patients with mild daytime hypoxaemia with or without sleep-related oxygen desaturation.

The aim of the present study was to compare the evolution of pulmonary haemodynamics and of arterial blood gases in chronic obstructive pulmonary disease (COPD) patients with mild-to-moderate hypoxaemia, with or without sleep-related oxygen desaturation. COPD patients with daytime arterial oxygen partial pressure in the range 56-69 mmHg were included prospectively. Sleep-related oxygen desaturation was defined as spending > or = 30% of the nocturnal recording time with arterial oxygen saturation <90%. From the 64 patients included, 35 were desaturators (group 1) and 29 were nondesaturators (group 2). At baseline (t0), patients with sleep-related desaturation had a significantly higher daytime (mean +/- SD) arterial carbon dioxide partial pressure (Pa,CO2) (44.9 +/- 4.9 mmHg versus 41.0 +/- 4.1 mmHg, p=0.001) whereas mean pulmonary artery pressure (mPAP) was similar in the two groups. After 2 yrs (t2) of follow-up, 22 desaturators and 14 nondesaturators could be re-evaluated, including pulmonary haemodynamic measurements. None of the nondesaturator patients became desaturators at t2. The difference between the two groups in terms of daytime Pa,CO2 was still present at t2. The mean changes in mPAP from t0 to t2 were similar between the two groups, as were the rates of death or requirement for long-term oxygen therapy (American Thoracic Society criteria) during follow-up of up to 6 yrs. The presence of sleep-related oxygen desaturation is not a transitional state before the worsening of daytime arterial blood gases, but is a characteristic of some chronic obstructive pulmonary disease patients who have a higher daytime arterial carbon dioxide partial pressure. Such isolated nocturnal hypoxaemia or sleep-related worsening of moderate daytime hypoxaemia does not appear to favour the development of pulmonary hypertension, nor to lead to worsening of daytime blood gases.

Adult↗
PubMed2000

Identification of a 49-kDa hydrophobic cell wall mannoprotein present in velum yeast which may be implicated in velum formation.

Analysis of velum-forming yeast cell wall components released by beta-1,3-glucanase treatment were compared with those of a non velum-forming yeast. SDS-PAGE electrophoresis and Western blotting with ConA-peroxidase staining of mannoproteins allowed us to identify a 49-kDa mannoprotein present in the cell wall of the velum-forming yeast and hardly visible in the control. The cell wall nature of this protein was confirmed by labelling with the non-permeable sulfosuccinimydiyl-6-(biotinamido)hexanoate reagent. A partial purification of this mannoprotein by anion exchange HPLC followed by surface hydrophobicity determination revealed that the fraction containing the 49-kDa mannoprotein was the most hydrophobic. Since cell surface hydrophobicity plays an important role in aggregate formation, it is likely that this mannoprotein is involved in velum formation.

Biotinylation↗
PubMed2000

Parenteral with enteral nutrition in the critically ill.

OBJECTIVE: To determine whether nutrient intake by early enteral nutrition with parenteral nutrition improves levels of retinol-binding protein and prealbumin (primary endpoint) and reduce morbidity and mortality (secondary endpoint) in ICU patients. DESIGN: Prospective, double-blind, and randomized, placebo-controlled study. SETTING: Two intensive care units in a tertiary institution. PATIENTS AND PARTICIPANTS: 120 patients in two groups of 60. INTERVENTIONS: Patients received either enteral plus parenteral nutrition (treatment group) or enteral nutrition plus placebo (placebo group) for 4-7 days after initiation of nutritional support. MEASUREMENTS AND RESULTS: Retinol-binding protein (P = 0.0496) and prealbumin (P = 0.0369) increased significantly in the treatment group from day 0 to day 7. There was no reduction in morbidity in ICU. There was no difference in OMEGA score (263 vs. 244) and length of stay in the ICU (16.9 vs. 17.3), but a reduction in length of stay at hospital (31.2+/-18.5 vs. 33.7+/-27.7, P = 0.0022). Mortality on day 90 (17 vs. 18) and after 2 years (24 vs. 24) was identical. CONCLUSIONS: Although it enhances nutrient intake and corrects nutritional parameters such as RBP and prealbumin more rapidly, within 1 week, supplemental parenteral nutrition has no clinically relevant effect on outcome in ICU patients at the early phase of nutritional support.

Analysis of Variance↗
PubMed1999

Occurrence of resveratrol and pterostilbene in age-old darakchasava, an ayurvedic medicine from India.

'Darakchasava' is a well known Indian herbal preparation of which the main ingredient is Vitis vinifera L. This 'ayurvedic' medicine is prescribed as a cardiotonic and also given for other disorders. HPLC analysis of this age old formulation revealed the presence of polyphenols like resveratrol and pterostilbene. These phenolic compounds are now known as antioxidants, cancer chemopreventive agents, and also known to reduce mortality from coronary heart disease by increasing high density lipoproteins like cholesterol and inhibiting platelet aggregation (Soleas, J.S., Diamandis, E.P., Goldberg, D.M., 1997. Resveratrol: a molecule whose time has come? and gone? Clin. Biochem. 30 (2), 91-113). The study of darakchasava becomes interesting in the light of these findings. A brief introduction of this medicinal preparation, its formulation, its analysis by HPLC, and some of its properties are discussed in this article.

Antineoplastic Agents, Phytogenic↗
PubMed1999

Multivariate analysis of predictors of cerebral vasospasm occurrence after aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: The role of type of treatment on cerebral vasospasm occurrence after aneurysmal subarachnoid hemorrhage (SAH) has not been studied. Through multivariate analysis we determined the independent prognostic factors of the occurrence of symptomatic vasospasm following aneurysmal SAH in a study cohort of 244 patients undergoing either surgical or endovascular treatment. The prognostic factors of sequelae after aneurysmal SAH were studied as well. METHODS: Symptomatic vasospasm was defined as the association of deterioration in a patient's neurological condition between 3 and 14 days after SAH with no other explanation and an increase in mean transcranial Doppler velocities of >120 cm/s. The prognostic factors were registered on admission and during the intensive care stay. RESULTS: Symptomatic vasospasm occurred in 22.2% surgical patients compared with 17.2% endovascular treatment patients (P=0.37). Multivariate analysis revealed that the probability of occurrence of symptomatic vasospasm decreased with age >50 years (relative risk [RR], 0.47 [0.25 to 0.88]) and severe World Federation of Neurological Surgeons (WFNS) grade measured on admission (RR, 0.43 [0.20 to 0.90]) and increased with hyperglycemia occurring during the intensive care stay (RR, 1.94 [1.04 to 3.63]). No difference in risk of symptomatic vasospasm could be identified between surgical and endovascular treatment. Symptomatic vasospasm (OR, 4.73 [CI, 1. 77 to 12.6]) as well as WFNS grade of >2 (OR, 8.95 [3.46 to 23.2]), treatment complications (OR, 8.39 [3.16 to 22.3]), and secondary brain insults were associated with an increased risk of 6-month sequelae. CONCLUSIONS: Age <50 years, good neurological grade, and hyperglycemia were all associated with an increased risk of cerebral vasospasm whereas treatment was not. This provides a basis for future clinical prospective randomized trials comparing both treatments.

Adult↗
PubMed1999

A randomized trial of nocturnal oxygen therapy in chronic obstructive pulmonary disease patients.

The beneficial effects of nocturnal oxygen therapy (NOT) in chronic obstructive pulmonary disease (COPD) patients with mild-to-moderate daytime hypoxaemia (arterial oxygen tension (Pa,O2) in the range 7.4-9.2 kPa (56-69 mmHg)) and exhibiting sleep-related oxygen desaturation remains controversial. The effectiveness of NOT in that category of COPD patients was studied. The end points included pulmonary haemodynamic effects after 2 yrs of follow-up, survival and requirement for long-term oxygen therapy (LTOT). Seventy-six patients could be randomized, 41 were allocated to NOT and 35 to no NOT (control). The goal of NOT was to achieve an arterial oxygen saturation of >90% throughout the night. All these patients underwent polysomnography to exclude an associated obstructive sleep apnoea syndrome. The two groups exhibited an identical meansD daytime Pa,O2 of 8.4+/-0.4 kPa (63+/-3 mmHg) at baseline. Twenty-two patients (12 in the NOT group and 10 in the control group, p=0.98) required LTOT during the whole follow-up (35+/-14 months). Sixteen patients died, nine in the NOT group and seven in the control group (p=0.84). Forty-six patients were able to undergo pulmonary haemodynamic re-evaluation after 2 yrs, 24 in the NOT and 22 in the control group. In the control group, mean resting pulmonary artery pressure increased from 19.8+/-5.6 to 20.5+6.5 mmHg, which was not different from the change in mean pulmonary artery pressure in the NOT group, from 18.3+/-4.7 to 19.5+/-5.3 mmHg (p= 0.79). Nocturnal oxygen therapy did not modify the evolution of pulmonary haemodynamics and did not allow delay in the prescription of long-term oxygen therapy. No effect of NOT on survival was observed, but the small number of deaths precluded any firm conclusion. These results suggest that the prescription of nocturnal oxygen therapy in isolation is probably not justified in chronic obstructive pulmonary disease patients.

Follow-Up Studies↗