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Biomedical subjects

P Duchene

Publications and source records attributed to P Duchene.

16 recordsLinked to original sources
PubMed2003

Nitrification preservation in activated sludge during curative bulking chlorination.

The bulking that occurs in biological wastewater treatment plants using activated sludge is very often controlled by the injection of sodium hypochlorite into the return activated sludge (RAS) stream. In the present study undertaken at two pilot plants fed with synthetic wastewater, the impact of the pass frequency of the sludge at the chlorine dosing point on the nitrifying flora is analysed. The pass frequency is one for the pilot plant 1 and two for the pilot plant 2. A dose of chlorine of 4.85 +/- 0.05 g/kg/MLVSS per day was applied at both pilots. The preservative effect on nitrifying activity of the lowest concentration of chlorine at the dosing point and therefore of the highest pass frequency was evidenced. Among other tools, a simple method of measurement of the oxygen uptake rate enabled us to monitor the effect of chlorination on nitrification before recording an increase in the ammonia concentration in the bulking.

Bacteria↗
PubMed1998

Stability of cephalosporin prodrug esters in human intestinal juice: implications for oral bioavailability.

The levels of degradation of cefetamet pivoxil (CAT), cefuroxime axetil (CAE), and cefpodoxime proxetil (CPD) in 0.6 M phosphate buffer (pH 7.4) and human intestinal juice (pH 7.4) at 37 degreesC over 24 h were compared. Significant differences in the time courses of degradation and in the patterns of degradation products were observed. (i) The relative proportions of the Delta2- and Delta3-cephalosporins were roughly reversed in the two incubation media. In phosphate buffer, the major degradation product was the Delta2-cephalosporin (CAT = 61%; CAE = 74%; CPD = 85%), while in intestinal juice it was the Delta3-cephalosporin (CAT = 86%; CAE = 75%; CPD = 87%). (ii) Generally, the degradation of the prodrug esters progressed faster in intestinal juice than in phosphate buffer (e.g., for CAT the half-lives [t1/2s] were 0.78 and 4.3 h, respectively). (iii) The two diastereoisomers of CAE and CPD were degraded at different rates in intestinal juice (for the CAE diasteroisomers, t1/2s = 0.37 and 0.93 h; for the CPD diastereoisomers, t1/2s = 0.18 and 0.98 h) but were degraded at similar rates in phosphate buffer (for the CAE diastereoisomers, t1/2 = 1.6 h; for the CPD t1/2 diastereoisomers, = 2.2 h). It is concluded that (i) the Delta2 isomerization does not significantly affect the bioavailability of prodrug esters since enzymatic hydrolysis in the intestinal fluid proceeds mainly to the active Delta3-cephalosporin and (ii) the high degree of stereoselectivity of the enzymatic ester hydrolysis should make it possible to increase the bioavailabilities of certain prodrug esters (CAE, CPD) by using the more stable diasterioisomer.

Administration, Oral↗
PubMed1989

Effects of biofeedback on childbirth pain.

A study of the effects of biofeedback on the pain of childbirth was conducted. Forty primigravidae were randomly assigned to either an experimental group or a control group. The experimental group was given a series of training sessions in biofeedback and used biofeedback equipment during labor. All subjects were monitored during the labor and delivery period for their reports of pain using a visual analogue scale (VAS) and a verbal descriptor scale (VDS). Results showed that women using biofeedback during childbirth reported significantly lower pain: from admission to labor and delivery (p less than 0.05:VDS; p less than 0.01:VAS), at delivery (p less than 0.005:VDS), and 24-hr postpartum (p less than 0.01:VDS). Also, women in the biofeedback group labored an average of 2 hr less and used 30% fewer medications. The results of this study suggest that EMG biofeedback may be effective in reducing levels of acute pain experienced by childbearing women.

Adult↗
PubMed1988

Metabolism of 14C-thymoxamine in rat and man.

1. After oral administration of 14C-thymoxamine to rat and man the total 14C excreted in urine and faeces was determined. 2. Six metabolites were isolated from the excret of man and rat by chemical extraction and identified by g.l.c.-mass spectral analyses. 3. Two other metabolites, highly polar and resistant to enzymic hydrolysis, were isolated by extraction on XAD2 resin and h.p.l.c. analysis. These two metabolites were identified by n.m.r. and by mass spectrometry in the fast atomic bombardment mode. 4. These two major metabolites of thymoxamine in man and rat have been identified and characterized as the sulphate conjugates of desacetyl-thymoxamine and N-monodesmethyl-desacetyl-thymoxamine.

Adult↗
PubMed1987

[pH and the bacteriology of gastroplasties after esogastric resection].

A study of pH of digestive fluid in 24 patients six days after esophagogastric resection (EGR) showed conservation of acidity (pH: 3 or less) in one-thirds of cases. Immediate postoperative course was invariable with respect to incidence of pneumopathy and fistulae. Fungal infection is almost a constant finding in digestive grafts together with microbial pullulation, with a linear relation to pH. Ecology of germs was that of digestive flora of patients with obstruction, selected by the antibiotic cover administered. Group D streptococci and Gram negative bacilli were usually resistant to cephalosporins. Regurgitation pneumopathy therefore requires modification of antibiotic therapy and possible antifungal treatment. When functional disturbance is provoked by EGR, as for example a reflux syndrome; only those patients (1/3) with a pH of 3 or less can obtain relief from treatment with antacids.

Adult↗
PubMed1985

Computerization of patient acuity and nursing care planning. New approach to improved patient care and cost-effective staffing.

Patient classification systems are essential for nurse administrators to justify nursing staff and to project budget. To answer these needs effectively, a computerized patient classification system must be customized to existing physical and human resources within each health care facility. Nursing administrators at Riverside Medical Center met this need by developing a computerized patient classification system that integrates patient acuity with patient care plans and nursing diagnoses. Direct cost accounting of nursing care according to patient needs and outcomes can be justified by correlating this management and practice data.

Computers↗
PubMedDate not supplied

Comparative bioavailability study of codeine and ibuprofen after administration of the two products alone or in association to 24 healthy volunteers.

The study objective was to compare the bioavailability of codeine and ibuprofen after oral administration of the two drugs alone or in association. The study was performed in three different periods, each separated by a wash-out of 6 days. Plasma concentrations were measured in 24 healthy volunteers after administration of a single oral dose of codeine phosphate (25 mg) and/or ibuprofen (200 mg). Codeine and ibuprofen assays were performed using two different HPLC methods. The relative bioavailabilities of codeine and ibuprofen (alone or in association) were 106 +/- 24% (mean +/- sd) and 101 +/- 19%, respectively. The results obtained demonstrated that bioavailabilities of codeine and ibuprofen were not modified when the two drugs were administrated alone or in association.

Adult↗
PubMedDate not supplied

Pharmacokinetics of reboxetine in healthy, elderly volunteers.

The pharmacokinetic characteristics of reboxetine, a unique selective noradrenaline reuptake inhibitor (selective NRI) for the treatment of depression, were studied in 12 healthy, elderly volunteers (mean age 81 years +/- 9 years). All subjects received a single 4-mg dose of reboxetine, and plasma reboxetine concentrations were measured by HPLC. Reboxetine was well tolerated by all subjects. Exposure to reboxetine was higher in this group of very elderly subjects, compared with data obtained in a similar study of young, healthy volunteers. Cmax in the elderly was 271 +/- 86 ng/ml, compared with 111 +/- 28 ng/ml in the young subjects after a single 4-mg dose, although in both groups Cmax was observed after 2 h. The AUC infinity was nearly four times that in the younger subjects (8345 +/- 3107 ng.h/ml vs. 2106 +/- 881 ng.h/ml) and the t1/2 was twice as long (24 +/- 6 h vs. 12 +/- 3 h). Renal clearance was also reduced. Reboxetine 8-10 mg/day has been effective and well tolerated in clinical trials in non-elderly depressed patients. The increased exposure to reboxetine observed in our very elderly subjects supports a reduction of the starting dose to 4 mg/day (in two divided doses) in the elderly.

Adrenergic Uptake Inhibitors↗