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Biomedical subjects

D Jacques

Publications and source records attributed to D Jacques.

At least 19 recordsLinked to original sources
PubMed2006

Respiratory variations in pulse oximeter waveform amplitude are influenced by venous return in mechanically ventilated patients under general anaesthesia.

BACKGROUND AND OBJECTIVES: Respiratory variations in pulse oximetry plethysmographic waveform amplitude (DeltaPOP) are related to respiratory variations in arterial pulse pressure (DeltaPP) in the critical care setting. The aims of this study were to test the hypothesis that in mechanically ventilated patients undergoing general anaesthesia, DeltaPOP calculation is feasible and can detect changes in preload. METHODS: Twenty-five mechanically ventilated patients were studied immediately after induction of general anaesthesia. Haemodynamic data (mean arterial pressure [MAP], central venous pressure [CVP], DeltaPP and DeltaPOP) were recorded at baseline, before and after tilting the patient from anti-Trendelenburg to Trendelenburg position in order to induce preload changes. RESULTS: Change from anti-Trendelenburg to Trendelenburg position induced changes in MAP (58 +/- 9 to 67 +/- 10 mmHg, P < 0.05), CVP (4 +/- 4 to 13 +/- 5 mmHg, P < 0.05), DeltaPP (14 +/- 8 to 7 +/- 5%, P < 0.05) and DeltaPOP (17 +/- 12 to 9 +/- 5%, P < 0.05). There was a significant relationship between DeltaPOP in anti-Trendelenburg position and percent change in MAP after volume expansion (r = 0.82; P < 0.05). CONCLUSIONS: DeltaPOP can be determined in the operating room and is influenced by changes in preload. This new index has potential clinical applications for the prediction of fluid responsiveness.

Adult↗
PubMed2006

Operator-splitting errors in coupled reactive transport codes for transient variably saturated flow and contaminant transport in layered soil profiles.

One possible way of integrating subsurface flow and transport processes with (bio)geochemical reactions is to couple by means of an operator-splitting approach two completely separate codes, one for variably-saturated flow and solute transport and one for equilibrium and kinetic biogeochemical reactions. This paper evaluates the accuracy of the operator-splitting approach for multicomponent systems for typical soil environmental problems involving transient atmospheric boundary conditions (precipitation, evapotranspiration) and layered soil profiles. The recently developed HP1 code was used to solve the coupled transport and chemical equations. For steady-state flow conditions, the accuracy was found to be mainly a function of the adopted spatial discretization and to a lesser extent of the temporal discretization. For transient flow situations, the accuracy depended in a complex manner on grid discretization, time stepping and the main flow conditions (infiltration versus evaporation). Whereas a finer grid size reduced the numerical errors during steady-state flow or the main infiltration periods, the errors sometimes slightly increased (generally less than 50%) when a finer grid size was used during periods with a high evapotranspiration demand (leading to high pressure head gradients near the soil surface). This indicates that operator-splitting errors are most significant during periods with high evaporative boundary conditions. The operator-splitting errors could be decreased by constraining the time step using the performance index (the product of the grid Peclet and Courant numbers) during infiltration, or the maximum time step during evapotranspiration. Several test problems were used to provide guidance for optimal spatial and temporal discretization.

Adsorption↗
PubMed2006

[Alcoholism treatments].

The problem of the alcoholic dependence entails often dramatic consequences: problems of health, acts of violence, traffic accidents, absenteeism at work and lost of social insertion. The alcohol has on the other hand a sociocultural registration in our way of life often associated with conviviality. The alcoholism is often defined by some as a disease, by the others as a social plague. It also differs according to the forms which it takes, its previous history and the functions which it performs. What definition can we accept? What are the therapeutic options to be implemented? Some answers will be considered through condiderations on the concept of motivation to change.

Alcohol Deterrents↗
PubMed2004

Sterilisation of intellectually disabled women.

OBJECTIVE: To point out the proportion of intellectually disabled women (IDW) who are sterilised, and the medical and social factors associated with an increased probability to be sterilised. STUDY DESIGN: A population-based study among 97% of IDW aged 18-46, attending government-accredited institutions in the region of Brussels-Capital and the province of Walloon Brabant (Belgium). RESULTS: Among the IDW included in this study, 22.2% are sterilised, which is superior to the 7% in the general Belgian population. Factors associated with an increased probability to be sterilised are: living in an institution, having a higher intellectual quotient (IQ), being enrolled in an institution where sexual intercourse is authorised and attending an institution where contraception is required. The last three factors are significant only among women living in institutions and the last two, only in women with severe disability. Among IDW using contraception, no factor was associated with a greater probability to be sterilised. CONCLUSION: The prevalence of sterilisation among IDW is three times higher than that in the Belgian population and it is mainly correlated with factors related to the institution where these women live, especially the severely disabled.

Adolescent↗
PubMed2003

Angiotensin II AT1 receptor internalization, translocation and de novo synthesis modulate cytosolic and nuclear calcium in human vascular smooth muscle cells.

The present study was designed to verify if human (h) Angiotensin II (Ang II) type-1 receptor (hAT1R) undergoes internalization, nuclear translocation, and de novo synthesis in primary culture of human aortic vascular smooth muscle cells (hVSMCs) and if overexpression of this receptor modulates sustained free cytosolic ([Ca]c) and nuclear ([Ca]n) calcium. 3-dimensional (3-D) confocal microscopy was used to monitor free intracellular Ca2+ and hAT1R-green fluorescence protein (GFP) fusion protein in cultured hVSMCs. Immunofluorescence studies showed the presence of hAT1R and the absence of hAT2R in normal hVSMCs. Using 3-D imaging technique, hAT1 receptors were localized at the sarcolemma and in the cytosolic and nuclear compartments. In native as well as in normal hAT1R or hAT1R-GFP overexpressing hVSMCs, Ang II (10(-9) and 10(-4) M) induced internalization and nuclear translocation of this type of receptor. The internalization of hAT1Rs is mediated via clathrin-coated pits and vesicles pathway. This phenomenon of trancellular trafficking of receptors was associated with an increase of hAT1R. The Ang II induced increase of hAT1R density was prevented by the protein synthesis inhibitor cycloheximide. Overexpression of hAT1R and hAT1R-GFP decreased both basal cytosolic and nuclear Ca2+. In normal hVSMCs and low hAT1R-GFP overexpressing hVSMCs, Ang II (10(-15) to 10(-4) M) induced a dose-dependent sustained increase of [Ca]c and [Ca]n with an EC50 near 5 x 10(-11) and 5 x 10(-9) M, respectively. Our results suggest that hAT1Rs are the predominant type of Ang II receptors in aortic hVSMCs and are present in the sarcolemma, the cytosolic and the nuclear compartments. Ang II rapidly induces hAT1R internalization, nuclear translocation, as well as nuclear de novo synthesis of this receptor. The hAT1R overexpression in hVSMCs modulates sustained [Ca]c and [Ca]n.

Aniline Compounds↗
PubMed2003

Enhanced mechanical properties of polyacrylonitrile/multiwall carbon nanotube composite fibers.

The use of multiwall carbon nanotubes (MWNTs) as a reinforcing phase in a polyacrylonitrile (PAN) fiber matrix was investigated with the goal of producing a PAN-derived carbon/MWNT composite fiber with enhanced physical properties. MWNTs were dispersed in a PAN/DMAc (dimethylacetamide) solution and spun into composite fibers containing up to 5 wt.% MWNTs, with the use of a lab-scale dry-jet wet spinline. The spinning process resulted in alignment of the MWNTs parallel with the fiber axis. Three types of chemical vapor deposition (CVD)-derived, high-purity MWNTs were used: as produced, graphitized (heat treated to 2800 degrees C), and NaCN-treated (chemically treated to attach CN groups to the nanotube surface). Tensile tests were performed to measure yield stress/strain, initial modulus, break stress/strain, and energy to yield and energy to break. Significant mechanical property increases were recorded for the composite fibers compared with the control samples with no MWNT reinforcement: break strength +31%, initial modulus +36%, yield strength +46%, energy to yield +80%, and energy to break +83%.

Acrylic Resins↗
PubMed2002

Contraception of women with intellectual disability: prevalence and determinants.

The contraception of women with intellectual disability (ID) is a major concern for caregivers. However, the prevalence of contraception and the frequency of use of different methods (e.g. sterilization) remain generally unknown. Moreover, indications specific to women with ID are controversial. The present authors conducted a population-based study among 97% of the women with ID aged between 18 and 46 years attending government-funded facilities in Brussels and the nearby province of Walloon Brabant in Belgium. Out of 397 subjects, 40.8% did not use any contraceptive method, 22.2% were sterilized, 18.4% used an oral contraceptive agent, 17.6% used depotmedroxyprogesterone acetate and 1% used an intrauterine device. These figures differ widely from those of the general Belgian population. Binary logistic regression for 'contraceptive utilization' showed the strong influence of institutional factors such as sleeping environment (i.e. institutional or parental), sexual relationship policy and contraception policy. Having or having had a boyfriend is also correlated with a stronger probability of contraceptive use. Other factors have a smaller influence (e.g. a milder level of ID). Very few factors, none of which are medical, are correlated with an increased use of a specific method. The present results are discussed in the light of the general medical application of contraception and the commonly assumed specific indications for women with ID.

Adult↗
PubMed2001

Cancer prone persons. A randomized screening trial based on colonoscopy: background, design and recruitment.

OBJECTIVE: Evidence-based counseling and prevention are not available so far for hereditary cancer prone persons, since we lack data based on clinical trials. There are very few high-risk persons in the population as a whole. Based on a familial history analysis, only 1.2% of all healthy volunteers attending screening centers reached the arbitrary high-risk level defined as a Relative Risk of more than 4. We describe a randomized trial based on colonoscopic screening for colorectal cancer on a sub-group of high-risk group persons. MATERIALS AND METHODS: Among the 77 members of the French Institutional Preventive Center Network, 37 took part in this protocol. During the first 3 years, 850,000 persons were interviewed at these 37 Health centers. The enrollment process was particularly time-consuming, since a large amount of information had to be delivered to the participants. RESULTS: The mean rate of recruitment of eligible candidates was far lower than predicted, averaging only 1.4 per 1,000 persons interviewed instead of the 9/1,000 expected. This mean figure was based, however, on inclusion rates ranging from 0.06/1,000 to 7/1,000 among the different centers. The low rates of recruitment were mainly due to the inter-center heterogeneity (differences in commitment and in the resources), and to the fact that the acceptability of undergoing a colonoscopy turned out to be lower than predicted. CONCLUSION: Population trials on cancer prone persons are feasible, but vast numbers have to be pre- screened to identify the few people with a high hereditary risk and willing to accept screening within a controlled trial.

Adolescent↗
PubMed2001

Telemedicine: cost-effective management of high-risk pregnancy.

PURPOSE: To evaluate the cost-effectiveness of telemedicine services in patients diagnosed with preterm labor (PTL). DESIGN: Women hospitalized with a diagnosis of PTL during a 3-year study period were identified within a health maintenance organization. INCLUSION CRITERIA: singleton gestation, stabilized after tocolysis and discharged from the hospital, and participation in the HMO's preterm-birth prevention program. After a PTL diagnosis, telemedicine services (home uterine activity monitoring with daily telephonic nursing contact) were authorized by the payer. The decision to prescribe telemedicine services was made by each patient's individual physician. Two groups of patients were identified: those who received telemedicine services (telemedicine group), and those who received standard care without the adjunctive outpatient service (control group). METHODS: Descriptive and statistical methods were used to compare maternal demographics, pregnancy outcome, antepartum hospitalization, delivery, nursery, and outpatient services. PRINCIPAL FINDINGS: One hundred women were identified: 60 in the telemedicine group and 40 in the control group. Gestational age at diagnosis of PTL was similar at 29.4 +/- 3.8 weeks, telemedicine group vs. 28.0 +/- 7.4 weeks, control group (P = 0.252). The telemedicine group had a significantly later mean gestational age at delivery (38.2 +/- 1.4 vs. 35.3 +/- 3.8), higher mean birth weight (3224 +/- 588 vs. 2554 +/- 911), fewer mean total nursery days (2.4 +/- 1.8 vs. 14.9 +/- 26.4), and less frequent admission to the neonatal intensive care unit (6.7 percent vs. 40 percent) than the control group (all P < 0.005). The total mean cost per pregnancy was $7,225 for the telemedicine group and $21,684 for the control group. This represented average savings of $14,459 per pregnancy using telemedicine services. CONCLUSION: Following an episode of PTL, use of telemedicine services can be a cost-effective tool to improve pregnancy outcome.

Adult↗
PubMed2000

BIIE0246, a potent and highly selective non-peptide neuropeptide Y Y(2) receptor antagonist.

1. BIIE0246, a newly synthesized non-peptide neuropeptide Y (NPY) Y(2) receptor antagonist, was able to compete with high affinity (8 to 15 nM) for specific [(125)I]PYY(3 - 36) binding sites in HEK293 cells transfected with the rat Y(2) receptor cDNA, and in rat brain and human frontal cortex membrane homogenates. 2. Interestingly, in rat brain homogenates while NPY, C2-NPY and PYY(3 - 36) inhibited all specific [(125)I]PYY(3 - 36) labelling, BIIE0246 failed to compete for all specific binding suggesting that [(125)I]PYY(3 - 36) recognized, in addition to the Y(2) subtype, another population of specific NPY binding sites, most likely the Y(5) receptor. 3. Quantitative receptor autoradiographic data confirmed the presence of [(125)I]PYY(3 - 36)/BIIE0246-sensitive (Y(2)) and-insensitive (Y(5)) binding sites in the rat brain as well as in the marmoset monkey and human hippocampal formation. 4. In the rat vas deferens and dog saphenous vein (two prototypical Y(2) bioassays), BIIE0246 induced parallel shifts to the right of NPY concentration-response curves with pA(2) values of 8.1 and 8.6, respectively. In the rat colon (a Y(2)/Y(4) bioassay), BIIE0246 (1 microM) completely blocked the contraction induced by PYY(3 - 36), but not that of [Leu(31), Pro(34)]NPY (a Y(1), Y(4) and Y(5) agonist) and hPP (a Y(4) and Y(5) agonist). Additionally, BIIE0246 failed to alter the contractile effects of NPY in prototypical Y(1) in vitro bioassays. 5. Taken together, these results demonstrate that BIIE0246 is a highly potent, high affinity antagonist selective for the Y(2) receptor subtype. It should prove most useful to establish further the functional role of the Y(2) receptor in the organism.

Animals↗
PubMed2000

Weekly dosing of fluoxetine for the continuation phase of treatment of major depression: results of a placebo-controlled, randomized clinical trial.

Fluoxetine (FLX) has a unique pharmacokinetic profile. Its major metabolite, norfluoxetine (NFLX), possesses FLX's antidepressant efficacy and a half-life of 7 to 15 days, suggesting the possibility of nonstandard dosing strategies. This study examined the tolerability of a weekly dose and its equivalence to daily dosing of FLX for the continuation phase of treatment for major depressive disorder (MDD). One hundred fourteen subjects initially received open-label treatment with 20 mg of FLX daily for 7 weeks. Subsequently, 70 subjects with a score on the Hamilton Rating Scale for Depression (HAM-D) of 12 or less were randomly assigned in a double-blind design to one of three treatment groups: 20 mg FLX daily (N = 21), 60 mg FLX weekly (N = 28), or placebo (N = 21) and were followed for 7 weeks. HAM-D scores and blood levels of FLX and NFLX were analyzed using a repeated-measures analysis of variance. During the double-blind phase, blood levels for both FLX and NFLX differed across the treatment groups, yet no statistically significant difference in HAM-D scores was observed. There was no difference in the dropout rate across the groups. Subjects could not correctly identify the treatment group into which they were assigned. Weekly dosing of FLX seems to be well tolerated and possibly as effective as daily dosing in maintaining the therapeutic response in subjects with MDD.

Adult↗
PubMed2000

Nitric oxide relaxes the vascular smooth muscle independently of endothelin-1- and U46619-induced intracellular increase of calcium.

A balance between circulating and locally released vasoconstrictors, such as endothelin-1 (ET-1), and vasodilators, such as nitric oxide, controls vascular smooth muscle tone. In the study reported here, using the technique of simultaneous measurements of intracellular free calcium ([Ca2+]i) and tension, we investigated the effects of a nitric oxide donor, sodium nitroprusside (NaNP) on endothelin-1- and U46619- [a thromboxane angiotensin-II (TXA-II) mimetic] induced sustained increases in tension and [Ca2+]i in intact and endothelium-denuded rabbit thoracic aortas. Our results showed that, in both intact and endothelium-denuded preparations, the nitric oxide donor NaNP (10(-6) M) reverses the ET-1- (10(-7) M) and U46619- (10(-7) M) induced sustained increase in tension but not in [Ca2+]i. However, it did not reduce the ET-1- and U46619-induced responses. Our data suggest that nitric oxide production modulates vascular smooth muscle tension via a mechanism that is independent of that generated by vasoconstrictors such as ET-1 and TXA-II.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed2000

Endothelin-1 regulates cytosolic and nuclear Ca2+ in human endocardial endothelium.

Endocardial endothelium is far less studied than its systemic and pulmonary counterparts and its role in cardiac function is not well known. In the study reported here, we succeeded in isolating and culturing endocardial endothelial cells (EECs) from 21-week-old human fetal heart and verified whether endothelin-1 (ET-1) receptors are present on these cells and whether their activation regulates cytosolic ([Ca]c) and nuclear calcium ([Ca]n). Using fluo-3 Ca2+ measurement and three-dimension confocal microscopy techniques, superfusion of fetal human EECs from right and left ventricles with increasing concentrations of ET-1 induced a dose-dependent sustained increase of free cytosolic and nuclear Ca2+ levels with an EC50 near 10(-10) M and 10(-11) M, respectively. The sustained increase of cytosolic and nuclear Ca2+ by ET-1 in both EEC preparations was completely blocked by the calcium chelator ethylene glycol-bis (beta-aminoethylether)-N,N,N',N'-tetra-acetic acid (EGTA) but was insensitive to the L-type Ca2+ channel blocker, nifedipine. The effect of ET-1 was prevented by the ET(A)-receptor antagonist BQ 123. However the ET(B)-receptor antagonist BQ 788 had no effect. Our results suggest that ET-1 receptors are present in human EECs and that their stimulation induces sustained Ca2+ influx through ET(A)-receptor stimulation of a nifedipine-insensitive Ca2+ channel, probably the R-type Ca2+ channel. The presence of Ca2+-dependent responses to ET-1 supports a possible modulatory role of the endocardial endothelium in myocardial functions.

Calcium↗
PubMed2000

Presence of functional endothelin-1 receptors in nuclear membranes of human aortic vascular smooth muscle cells.

Our previous work showed that the nucleus plays a role in excitation-contraction coupling and that the channels and receptors could be present at the nuclear membrane. In the study reported here, the objective was to test the hypothesis that endothelin-1 (ET-1) receptors are functional at the level of the nuclear membranes and that their stimulation importantly regulates free nucleoplasmic Ca2+ level. Using a Fluo-3 Ca2+ measurement technique in human vascular smooth muscle cells (HVSMC), superfusion with increasing concentrations of extracellular ET-1 induced a dose-dependent sustained increase of free cytosolic ([Ca]c), nuclear ([Ca]n) Ca2+ and contraction with an EC50 near 3 x 10(-10) M. Like the extracellular ET-1, the cytosolic application of ET-1 using the perforated sarcolemma membrane technique, induced a dose-dependent increase of nuclear free calcium of HVSMC with an EC50 of 2 x 10(-11) M. These results strongly suggest that ET-1 receptors are functional at the level of the nuclear membranes. Furthermore, the sensitivity of ET-1 receptors at the nuclear membrane level seems to be higher than that of the receptors at the sarcolemma membrane. Finally, our results suggest that cytosolic ET-1 may play a role in preventing HVSMC nuclear calcium overload, thus protecting the cells from apoptosis.

Adult↗
PubMed2000

Neuropeptide Y induced increase of cytosolic and nuclear Ca2+ in heart and vascular smooth muscle cells.

It was reported that neuropeptide Y (NPY) affects cardiac and vascular smooth muscle (VSM) function probably by increasing intracellular Ca2+. In this study, using fura-2 microfluorometry and fluo-3 confocal microscopy techniques for intracellular Ca2+ measurement, we attempted to verify whether the action of NPY receptor's stimulation in heart and VSM cells modulates intracellular Ca2+ and whether this effect is mediated via the Y1 receptor type. Using spontaneously contracting single ventricular heart cells of 10-day-old embryonic chicks and the fluo-3 confocal microscopy Ca2+ measurement technique to localize cytosolic ([Ca]c) and nuclear ([Ca]n) free Ca2+ level and distribution, 10-10 M of human (h) NPY significantly (P < 0.05) increased the frequency of cytosolic and nuclear Ca2+ transients during spontaneous contraction. Increasing the concentration of hNPY (10(-9) M) did not further increase the frequency of Ca2+ transients. The L-type Ca2+ channel blocker, nifedipine (10(-5) M), significantly (P < 0.001) blocked the spontaneous rise of intracellular Ca2+ in the absence and presence of hNPY (10(-10) and 10(-9) M). However, the selective Y1 receptor antagonist, BIBP3226 (10(-6) M), significantly decreased the hNPY-induced (10(-10) and 10(-9) M) increase in the frequency of Ca2+ transients back to near the control level (P < 0.05). In resting nonworking heart and human aortic VSM cells, hNPY induced a dose-dependent sustained increase of basal resting intracellular Ca2+ with an EC50 near 10(-9) M. This sustained increase was cytosolic and nuclear and was completely blocked by the Ca2+ chelator EGTA, and was significantly decreased by the Y1 receptor antagonist BIBP3226 in both heart (P < 0.05) and VSM (P < 0.01) cells. These results strongly suggest that NPY stimulates the resting basal steady-state Ca2+ influx through the sarcolemma and induces sustained increases of cytosolic and nuclear calcium, in good part, via the activation of the sarcolemma membrane Y1 receptor type in both resting heart and VSM cells. In addition, NPY also increased the frequency of Ca2+ transients during spontaneous contraction of heart cells mainly via the activation of the Y1 receptor type, which may explain in part the active cardiovascular action of this peptide.

Animals↗
PubMed1999

Impact of the fetal fibronectin assay on admissions for preterm labor.

OBJECTIVE: The aim of the study was to determine whether use of the fetal fibronectin assay would decrease the number of admissions to labor and delivery for diagnosis and treatment of preterm labor. STUDY DESIGN: A prospective cohort design was used to compare preterm labor admissions during a 12-month period of fetal fibronectin assay use (study) against a baseline period before fetal fibronectin assay was implemented as standard protocol. Patients coming to the physician's office or hospital with signs and symptoms of preterm labor had a sample obtained for fetal fibronectin assay per labeling criteria. Comparisons were made with the Mann-Whitney U test, independent Student t test, chi2 test, and Fisher exact test. P <.05 was considered significant. RESULTS: There was no difference noted in the number of deliveries between the baseline and study years. During the study year 251 of 330 patients evaluated for preterm labor met study criteria and had the fetal fibronectin assay completed. Eight patients did not have fetal fibronectin assay results available because of specimen handling errors, leaving 243 subjects available for study. Compared with the baseline year, the study year had significantly fewer admissions for preterm labor, preterm labor admissions per patient, and prescriptions written for tocolytic agents. In addition, the length of stay per admitted patient was significantly reduced. The study population had no differences in neonatal outcomes from the baseline population in terms of deliveries at <35.0 weeks' gestation, number of admissions to the neonatal intensive care unit, neonatal intensive care unit length of stay, or days of ventilatory support per patient admitted to the neonatal intensive care unit. CONCLUSIONS: Use of the fetal fibronectin assay resulted in significantly reduced preterm labor admissions, length of stay, and prescriptions for tocolytic agents. No negative impact on neonatal outcomes was observed. Reductions in admissions for preterm labor and in charges per admission resulted in approximately $486,000 saved during the study period. A trend toward increased corticosteroid administration (for neonates ultimately admitted to the neonatal intensive care unit) was noted.

Adolescent↗