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Biomedical subjects

C Bardin

Publications and source records attributed to C Bardin.

32 records · Page 2Linked to original sources
PubMed1997

Attitudes toward obstetrics training. Residents surveyed at McGill University and University of Montreal.

OBJECTIVE: To determine family medicine residents' attitudes toward family practice training in obstetrics and neonatology before and after implementation of a modified obstetrics curriculum at McGill University (MG). DESIGN: Two-group pretest and posttest. Fifty-seven respondents, 31 at MG, 26 at University of Montreal (UM), were case matched as first-year and second-year residents. SETTING: Departments of Family Medicine at MG and UM. PARTICIPANTS: Family medicine residents at MG and UM. INTERVENTION: A modified obstetrics curriculum was introduced at MG (study group); no modifications were introduced at UM (control group). First- and second-year residents' attitudes toward the adequacy of training were assessed through responses to a questionnaire administered in July 1992 and July 1994. MAIN OUTCOME MEASURES: Changes in response scores before and after implementation of the modified curriculum. RESULTS: Repeated multivariate analysis of variance (MANOVA) showed respondents believed family practice obstetrics training was adequate in general, but that family practitioners were inadequately trained in emergency obstetric skills. Scores for items assessing neonatology skills increased significantly in the MG group after the intervention. CONCLUSIONS: Residents' overall confidence in their obstetrics training did not appear to improve, but this might be due to a time lag between curriculum modification and attitudinal change. McGill residents' confidence in neonatology skills improved significantly after curriculum modification.

Adult↗
PubMed1997

Extreme insulin resistance: clinical management by external subcutaneous insulin infusion.

Management of very high insulin requirements in rare extreme insulin resistance syndromes is difficult and poorly documented. We report a case of a type B insulin-resistant patient requiring approximately 10,000 units of insulin per day, i.e. beyond the possibilities of current insulin formulations and delivery devices. Only the Panomat C10 portable pump model (Disetronic) and U500 Humulin (Lilly) allowed the required rate of 400 units per hour to be attained only when the reservoir was changed twice daily and the site and catheter were changed once daily. Three months after discharge, the patient was in good general and local condition, but with only fair diabetes control (glycated haemoglobin 9.5%).

Adult↗
PubMed1996

Low plasma concentrations achieved with conventional schedules of administration of ganciclovir in patients with AIDS.

Plasma concentration of ganciclovir was studied prospectively in 15 AIDS patients treated for acute cytomegalovirus (CMV) retinitis. Ganciclovir was administered at a mean dose of 10.3 +/- 0.6 mg/kg/day. The mean trough plasma concentration was 0.6 +/- 0.3 mg/L (n = 24), and the mean peak concentration was 7.2 +/- 2.4 mg/L (n = 6). In 12 patients, trough concentrations were below the range that has been associated with effective treatment. Low trough concentrations were associated with treatment failure in 6 patients. Following an increase in the daily dose, improvement was observed in 4 of the 6 patients. These results suggest that low plasma ganciclovir levels are associated with the failure of therapy. Monitoring the plasma concentration of ganciclovir may thus be useful before considering the virus to be resistant to the drug or before switching from ganciclovir to foscarnet.

AIDS-Related Opportunistic Infections↗
PubMed1996

Calcium lactate interference in measuring creatinine in peritoneal dialysis fluids by the Jaffé kinetic method.

Creatinine measurements in peritoneal dialysis fluids using the Jaffé method have poor specificity due to interfering substances. We have checked to see if calcium lactate, in addition to glucose, interferes with the Jaffé kinetic measurement. Eight samples were prepared with increasing concentrations of glucose (960-3890 mg/dL) and eight were prepared with the same glucose content plus 7 mg/dL of calcium lactate, all without creatinine; in addition, 96 samples with increasing concentrations of glucose (1500-4000 mg/dL), calcium lactate (3-7.5 mg/dL), and creatinine (0.75-4.5 mg/dL) were prepared. There was a 0.31 +/- 0.13 mg/dL glucose interference on the Jaffé kinetic measurement in the first series, with an exponential trend. Interference was greater with calcium lactate and glucose: 0.50 +/- 0.16 mg/dL with the same trend. Data from the second series confirm the overestimation: 0.54 +/- 0.05 mg/dL (32.6%) with an exponential trend. The interference of glucose, creatinine, and calcium lactate on the Jaffé kinetic measurement was obtained by multi-variate regression. The single effects of glucose2 and glucose are predominant, but both creatinine and calcium lactate have a significant effect. Our study highlights the nonlinear glucose interference on creatinine measurement with the Jaffé kinetic method and the linear interference of both calcium lactate and creatinine.

Creatinine↗
PubMed1995

Correction of glucose concentration interference on Jaffé kinetic creatinine assay in peritoneal dialysis.

Overestimation of creatinine measurement using the Jaffé kinetic method in peritoneal dialysis solutions, due to glucose interference, has been quantified and corrected through the elaboration of linear formulas obtained from 110 recovery and 301 biological tests. The added pure powdered creatinine and enzymatic method were considered as references after proven accuracy. Considering creatinine as well as glucose concentration interference, we obtained correction formulas from multiple regression application. All the computed formulas gave satisfactory corrections but different accuracy levels. The best model in biological samples was: Corrected CR = K1JafféCr + K2Glucose (all values in mg/dl) where K1 = 0.973 and K2 = -0.00035 (Rsq = 0.987, F ratio = 10,945, p = 0.00001). Applying formulas to biological samples there was a drop in accuracy, possibly explained by the presence of numerous unidentified substances in peritoneal dialysis biological samples that can amplify scatter. Every laboratory can reduce the error of the Jaffé kinetic assay by calculating their own correction formula in relation to the method and instrument used, because Jaffé kinetic assay gives different results with different kinetic windows. So, especially when applied to peritoneal dialysis fluid measurements, if a creatinine assay reference method is not available, the correction formula can be applied directly as given. Otherwise the method we have described can be followed with a well-structured creatinine recovery fest to identify and quantify assay interferences.

Analysis of Variance↗
PubMed1992

Bioavailability of fluoride in postmenopausal women: comparative study between sodium fluoride and disodium monofluorophosphate-calcium carbonate.

Fluoride (F) increases trabecular bone mass and can be used in the treatment of osteoporosis with crush fractures. As the bioavailability of sodium fluoride (NaF) can be impaired by concomitant absorption of calcium, both drugs have to be ingested separately. However, disodium monofluorophosphate-calcium carbonate (MFP-Ca), another F compound, allows a single administration. In a cross-over randomized study, we compared the bioavailability of both drugs under regular conditions of prescription. Ten postmenopausal women (aged 48-77 years) with glomerular filtration rate (GFR) greater than 70 ml/minute and without bone disease entered the study. Each received 25 mg of NaF [i.e., 11.3 mg F ion (F-)] fasting and 100 mg of Na2FPO3-1250 mg CaCO3 (i.e., 13.2 mg F-) with breakfast in a single dose separated by an 8-day washout. After dosing, plasma F levels and fractionated and total urinary F collection were determined during a 24-hour period using a specific electrode. Results show a significant shorter lag time absorption (Tmax = 1.4 +/- 0.2 hour) and a higher maximal concentration (Cmax = 260 +/- 60 ng/ml) for MFP-Ca than for NaF (Tmax = 2.5 +/- 0.4 hour; Cmax = 200 +/- 85 ng/ml). However, areas under curve (AUC) for MFP-Ca (1711 +/- 195 micrograms/liter/hour) and for NaF (1202 +/- 147 micrograms/liter/hour) were not significantly different. The relative bioavailability of both F compounds related to their fluoride content (i.e., 1.22 for AUC ratio) was equivalent, according to the Westlake method. These data provide the first evidence of comparable bioavailability of two F compounds in a population of postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Systemic morphine pharmacokinetics after ocular administration.

Pharmacokinetics of a single dose of morphine ocularly applied is reported in rabbits before and after lacrimal canaliculi ligature. Our investigations are based on a sensitive reversed-phase ion-pair chromatographic determination of morphine. This study describes the various resorption sites of morphine when administered through the conjunctiva. After ocular administration, morphine rapidly reaches high blood levels compatible with pharmacological activity. Ocular bioavailability of morphine is higher than after non-parenteral routes. Canaliculi ligature modifies the morphine pharmacokinetic profile without significant modification of drug bioavailability. Our results suggest a great capacity of drug resorption for the conjunctiva, and indicate the major role of nasal mucosa in physiological conditions.

Animals↗
PubMed1987

Reduced expression of multiple forms of the alpha subunit of the stimulatory GTP-binding protein in pseudohypoparathyroidism type Ia.

We examined the expression of the alpha subunit of the stimulatory GTP-binding protein (Gs) in fibroblasts of subjects with pseudohypoparathyroidism (PHP) type Ia by transfer blot hybridization and S1 nuclease analyses. Six subjects with PHP type Ia showed decreased steady-state content of Gs alpha mRNA. S1 nuclease analysis indicates that both long and short forms of Gs alpha mRNA are decreased, with no apparent change in the ratio of long to short forms in PHP compared with normal individuals. It appears likely that in some cases of PHP type Ia the genetic lesion affects the maintenance of mRNA levels for all forms of the Gs alpha subunit.

DNA↗
PubMed1984

Biosynthesis of peptidoglycan in Gaffkya homari: processing of nascent glycan by reactivated membranes.

Membranes from Gaffkya homari reactivated by freezing and thawing were used to study the processing events involved in the assembly of both sodium dodecyl sulfate (SDS)-insoluble peptidoglycan (PG) and SDS-soluble PG. The ability to reactivate membranes for the synthesis of these polymers provided an opportunity to monitor those events that are not influenced by wall-linked PG. In G. homari, processing for the formation of cross-links requires the selective actions of DD-carboxypeptidase, LD-carboxypeptidase, and NE-(DAla)-Lys transpeptidase. Time courses of cross-link formation, as measured by the amounts of amidated bisdisaccharide peptide dimer and nonamidated bisdisaccharide peptide dimer, showed a lack of correlation with those for the synthesis of SDS-insoluble PG. SDS-soluble PG, which is significantly cross-linked when synthesized in the absence of penicillin G, was a precursor of the SDS-insoluble PG. In the presence of penicillin G, un-cross-linked SDS-soluble PG was synthesized. This PG was also utilized and processed for the synthesis of cross-linked SDS-insoluble PG after removal of the beta-lactam. This protocol provided a method for separating stages in the synthesis and elongation of PG from those involved in processing. Cross-linkage in the various PG fractions ranged from 0 to 19% in SDS-soluble PG and from 2 to 24% in SDS-insoluble PG. Thus, the results indicated that there is no direct correlation between SDS insolubility and the degree of cross-linkage. Instead, they suggested that additional features may contribute to the insolubility of PG in SDS.

Acetylglucosamine↗
PubMed1982

Biosynthesis of peptidoglycan in Gaffkya homari: reactivation of membranes by freeze-thawing in the presence and absence of walls.

The reactivation of membranes from Gaffkya homari for the synthesis of sodium dodecyl sulfate-insoluble peptidoglycan (SDS-insoluble PG) was achieved by successive cycles of freeze-thawing (- 196 versus 25 degrees C). The presence of G. homari walls during this process affected the synthesis of both SDS-soluble (nascent) and SDS-insoluble PG. At two cycles the synthesis of SDS-soluble PG decreased by 70%, whereas that of SDS-insoluble PG increased sevenfold when compared with membranes reactivated in the absence of walls but assayed in the presence of walls. Moreover, at six cycles the lag time for the synthesis of SDS-insoluble PG decreased from 15 min to 5 to 7 min. Walls from G. homari could not be replaced with walls from Bacillus megaterium or cellulose. In addition to these effects, the presence of walls from G. homari or B. megaterium or of cellulose during the incubation of membranes freeze-thawed in the absence of walls increased twofold the amount of SDS-insoluble PG. Reactivated membranes showed greater sensitivities to penicillin (an inhibitor of dd-carboxypeptidase) and d-methionine (an inhibitor of ld-carboxypeptidase) than did isolated membrane-walls. The percentage of cross-linking of the SDS-insoluble PG synthesized by the reactivated system was 34%, a value similar to that observed for the polymer synthesized by isolated membrane-walls. Freeze-thawing membranes and walls together gave a complex with a density different from that of either membranes or walls. Thus, the assembly system for the synthesis and processing of PG was reconstituted in a complex of membranes and walls prepared from the isolated components. Whether this complex has the exact interrelationship between membrane and wall found in the organism has not been established.

Cell Fractionation↗
PubMed1978

Sodium-dependent amino acid transport in reconstituted membrane vesicles from Ehrlich ascites cell plasma membranes.

Plasma membranes, isolated from Ehrlich ascites tumor cells, were dissolved in 2% cholate, 4 M urea and then reformed into liposomes upon dialysis at 4 degrees with exogenous phospholipids. Reconstituted vesicles regain the ability to transport amino acids. Na+ was shown to accelerate the uptake of alpha-aminoisobutyrate, phenylalanine, and methionine, but not leucine or epsilon-aminohexanoic acid. With the reconstituted vesicles, methionine, but not leucine, inhibited the uptake of alpha-aminoisobutyrate. An apparent Km value for alpha-aminoisobutyrate uptake of 3.0 mM was obtained. This value is close to that observed with the intact cells and the native membrane vesicles. A Na+ gradient (high Na+ outside) increased alpha-aminoisobutyrate uptake, whereas a reversed gradient (high Na+ inside) increased alpha-aminoisobutyrate efflux. The latter flux was increased by valinomycin, suggesting electrogenic transport. A modest extent of coupling between a Na+ gradient and uphill flow of alpha-aminoisobutyrate was observed.

Amino Acids↗
PubMed1976

Uptake of amino acids in reconstituted vesicles derived from plasma membranes of Ehrlich ascites cells.

To obtain a clearer concept of the mechanism of organic solute transport in mammalian cells, we have attempted to reconstitute a functional transport system for amino acids from plasma membranes of Ehrlich ascites cells. Purified plasma membranes were dissolved in 2% Na cholate--4 M urea, a mixture which brought over 85% of the membrane proteins into solution. After centrifugation of the solubilized material for 2 hrs at 100,000 x g, the supernatant was dialyzed in the cold for 20 hrs with additional lipid. The reformed vesicles were tested for the ability to transport amino acids. The preliminary results obtained show that the uptake of alpha-aminoisobutyric acid can be inhibited by L-methionine and much less by L-leucine as would be predicted from the known properties of alpha-aminoisobutyric transport in the intact cells. In addition, it has been possible to show accelerated efflux of intravesicular phenylalanine when phenylalanine is added to the trans side (medium side). The data are consistent with the conclusion that there is carrier mediated transport in the reconstituted vesicles.

Amino Acids↗
PubMedDate not supplied

[Pharmacokinetics of ofloxacin administered orally in elderly subjects with bronchial or urinary tract infections].

The pharmacokinetics of ofloxacin orally administered were investigated at the steady-state in sixteen elderly patients older than 65 years. Patients with either urinary tract of respiratory tract mild infectious were divided into two age-dependent groups A and B. Group A: eight patients (65-80 years) received 200 mg of ofloxacin by the oral route every 12 hours and group B: eight patients older than 80 years, received 200 mg of ofloxacin by the oral route every 24 hours. The pharmacokinetic study was performed on treatment day 5. Plasmatic levels and urinary excretion of ofloxacin during 12 or 24 hours were assayed by means of high pressure liquid chromatography. Wide variations in plasma ofloxacin concentrations were observed within each group (Cmax range, group A: 1.9-9.2 mg/l, group B: 1.6-10.0 mg/l). Similar variability was observed for ofloxacin elimination parameters (CI/F, renal CI(R)/F) and half-life. In contrast, within-group and between-group differences in the volume of distribution adjusted for weight were not significant (group A: 1.22 +/- 0.44 l.kg; group B: 1.49 +/- 0.53 l.kg), but these values were approximately half those observed in the young adult. Plasmatic [CI/F] and renal clearance [CI(R)/F] of ofloxacin were correlated with creatinine clearance in both groups and in the overall population studied. Then the overall population was classified in terms of creatinine clearance [group 1: greater than 50 ml/min; group 2: less than or equal to 50 (minimum 20) ml/min]. The pharmacokinetics of ofloxacin in the elderly are characterized by a decrease in the volume of distribution and in plasmatic and renal clearances.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗