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S Robert

Publications and source records attributed to S Robert.

68 records · Page 4Linked to original sources
PubMed1991

Monitoring serum digoxin concentrations during digoxin immune Fab therapy.

Measurement of serum digoxin concentrations (SDCs) is used routinely in the diagnosis of digoxin toxicity. Following administration of the antidote, digoxin immune antigen binding fragments (Fab), SDC monitoring is hampered by assay-related problems because of the presence of Fab in the serum. Recent evidence has suggested several available methods to monitor free SDC during Fab therapy. This report describes the utility of monitoring free SDC following Fab administration. Free SDCs were obtained using an ultrafiltration and fluorescence polarization immunoassay system in three patients over periods of up to 204 hours after Fab administration. In each case, the decline in free SDC was temporally related to the resolution of digoxin toxicity; in one case, digoxin intoxication recurred and was associated with a rebound increase in free SDC. In addition to the therapeutic benefits, prospective monitoring of free SDC in two of the patients also may have resulted in cost savings secondary to reduced hospital stay or less use of Fab.

Adult↗
PubMed1991

Effect of feeding regimen on behavior of growing-finishing pigs supplemented or not supplemented with folic acid.

The effect of restricted feeding on the frequency of abnormal behaviors and gastric ulcers was investigated in 72 market pigs. Half of the pigs were fed restricted (R) amounts of feed twice a day (0800 and 1600) and received 90 to 95% of the intake recorded for the other half, which were allowed ad libitum (A) access to feed with addition of feed once a day at 0800. In each feeding group, 24 pigs were supplemented with folic acid. The animals were housed in pairs and the behavior of each animal was recorded during 24 h at 18 and 20 wk of age. The results showed that the A group ate more frequently during light hours than the R group at 18 wk, but not at 20 wk. However, the frequency of eating behavior was higher in the R group than in the A group at 20 wk during the 2 h after feed distribution. Feeding regimen had an effect on the frequency of redirected behaviors during the 2 h preceding feed distribution. The percentage of time spent nibbling on the penmate was higher in R than in A pigs at 18 wk, whereas that of rooting on the penmate was higher at 20 wk. Moreover, the proportion of pigs performing redirected behaviors was higher in the R than in the A group at both ages. The overall frequency of gastric ulcers was similar in pigs given the two feeding treatments, but severe ulcers were more frequent in the R than in the A group. Some interactions were also found between feeding regimen and folic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1991

Effects of continuous stray voltage on health, growth and welfare of fattening pigs.

The effects of continuous stray voltage were evaluated on growing-finishing pigs between the ages of 8 and 21 weeks. Seventy-two pigs were assigned to six blocks of 12 animals each. The following treatments were randomly distributed in each block according to a 2 x 3 factorial design: feeding level (restricted or ad libitum) and voltage level (0, 2 or 5 volts (V) as a difference of potential between feeder or drinker and the metallic floor). During daytime, stray voltage at 5 V decreased (p less than 0.05) the eating frequency in both feeding groups and the drinking frequency in restricted-fed pigs. The mean duration of drinking bouts and the total time spent at the drinker were also lower (p less than 0.05) in this last group during the hour following meal distribution. Daily feed intake and average daily gain were lower (p less than 0.05 and less than or equal to 0.08, respectively) in the 5 V group than in the 2 V and the control groups from 17 to 21 weeks of age. Finally, gastric lesions, hematological and biochemical variables were not affected (p greater than 0.05) by stray voltage.

Animals↗
PubMed1991

Ticlopidine: a new antiplatelet agent for cerebrovascular disease.

Ticlopidine is a new prototype antiplatelet drug chemically unrelated to currently available agents. It causes an alteration in platelet membrane reactivity to a variety of aggregating stimuli and a marked prolongation of bleeding time, the mechanism of which remains unclear. Two major phase III multicenter trials, the ticlopidine-aspirin stroke study (TASS) and the Canadian-American ticlopidine study (CATS) reported that the agent may reduce the occurrence of stroke, myocardial infarction, or vascular death in patients of both sexes who have had recent cerebral ischemia. Ticlopidine has been well tolerated in preliminary studies, with the most commonly described adverse effects being rash and gastrointestinal complaints. The most important adverse effect is neutropenia, which was reported in both TASS and CATS, approximating a frequency of 0.9% and 0.8%, respectively. Ticlopidine holds considerable promise as adjunctive therapy in selected patients.

Cerebrovascular Disorders↗
PubMed1991

Body composition analysis by bioelectrical impedance: the effects of time of day and body side on estimated gentamicin pharmacokinetics.

To assess if repetitive measures are useful in a clinical setting, the effects of time of day and body side on bioelectrical impedance (BI) measurements were evaluated. Fifteen healthy, male volunteers underwent serial BI measurements at 0, 3, 6, 9, 24, and 48 hours on both sides of the body using a four-electrode plethysmograph. Analysis of variance for repeated measures indicated that the mean resistance (R) value of the right side was statistically lower from that of the left side (447 +/- 27.9 vs 457 +/- 29.1 ohms; p = 0.006). Both R and reactance (Xc) varied significantly over time. For R, the mean response at 0, 6, 9, and 48 hours was different from the overall mean of the remaining time points (p less than 0.007). Only times 6 and 24 hours were significantly different for Xc (p less than 0.006). No relevant time and side effects were noted in calculated gentamicin pharmacokinetic parameters on incorporation of BI measurements into impedance-derived predictive equations for clearance, volume of distribution, and elimination constant. Correlation coefficients of reliability were high within 1 day and across days (R greater than or equal to 0.8407). These data suggest that under normal conditions, BI analysis provides reliable results, and that time and side standardizations in its measurements are not necessary.

Adult↗
PubMed1990

Effects of intramuscular injections of folic acid on serum folates, haematological status and growth performance of growing-finishing pigs.

In a first trial, 48 piglets aged 5 weeks, grouped into 6 blocks of 8 pigs each, were used to determine the effect of intramuscular injections of folic acid on serum folates, haematological status, growth performance and carcass characteristics. Each block consisted of 2 pens of 4 pigs; in one pen, pigs received, by weekly intramuscular injections, an increasing volume of a solution containing 5 mg/ml folic acid, while in the other the animals were non-injected controls. The concentration of serum folates in treated pigs was 19% higher (P = 0.005) than in controls. There was no effect of treatment (P greater than or equal to 0.29) on haemoglobin and haematocrit. During the starting period, (5-11 weeks) average daily gain was not influenced by folic acid injections but feed intake and feed conversion were decreased (P = 0.07 and P = 0.05 respectively). No effect of folic acid (P greater than or equal to 0.23) was noted from 11-23 weeks of age, suggesting that the supplement was suboptimal during the growing-finishing period. In a second trial, 72 piglets aged 9 weeks were assigned to 6 blocks of 12 animals each. The following treatments were randomly distributed in each block according to a 2 x 3 factorial design: level of feeding (restricted vs ad libitum) and weekly intramuscular injections of increasing volume of solutions containing either 0, 15 or 30 mg/ml of folic acid. The variables studied were the same as in Trial 1. Concentrations of serum folates varied quadratically (P = 0.0001) with the dose injected, a plateau being attained with injections of 15 mg/ml. There was no effect of treatment (P = 0.043) on haemoglobin and haematocrit. During the growing period (9-15 weeks), no effect (P greater than or equal to 0.72) of folic acid was noted on growth performance. However, during the finishing period (15-21 weeks), folic acid given at a dose of 30 mg/ml decreased (P = 0.006) feed intake while no effect (P greater than or equal to 0.13) of the vitamin supplementation was noted on average daily gain and feed conversion. In both trials, there was no effect (P greater than or equal to 0.21) of any treatments on carcass characteristics. These results indicate that a supplement of folic acid administered by intramuscular injections was effective in increasing concentration of serum folates of starting or growing-finishing pigs. This supplement may be associated with a decrease in feed intake.

Animal Feed↗
PubMed1989

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Commitment of Persons with Psychiatric Disorders↗
PubMed1989

[Anesthesia for extracorporeal lithotripsy in the treatment of renal lithiasis].

Extracorporeal shock wave lithotripsy has become the main technique for treating renal lithiasis. It has many repercussions on anaesthesia. The fundamental technical concepts of lithotriptors are reviewed. The problems due to the different systems (electrohydraulic or piezoelectric--the most widespread in France) are discussed. Electrohydraulic systems, which are more adapted to the treatment of large stones (diameter greater than 2 cm), require the immersion of the patient. As a result, there are analgesic, cardiovascular, respiratory and temperature repercussions on the anaesthetic management of these patients. General anaesthesia is generally more appropriate for this technique. On the other hand, piezoelectric systems are more adapted to the treatment of medium-sized or small calculi (diameter less than 2 cm), and do not require immersion. Anaesthesia is often not required for the use of this technique, but, if necessary, local, regional or general anaesthesia may be used. For either technique, the anaesthetic protocol must be adapted to the patient's and the surgical indications.

Anesthesia↗
PubMed1986

Polygraphic analysis of the sleep-wake states and the REM sleep periodicity in domesticated pigs (Sus scrofa).

Electrocorticography and concurrent electromyography were used during a total of nineteen 24 hr periods in three juvenile pigs in order to establish the quantitative duration of the sleep-wake states and the REM sleep cycles. Wakefulness (W), drowsiness (DR), slow-wave sleep (SWS) and paradoxical sleep (REM) occupied respectively 46.5%, 15.9%, 26.7% and 10.9% of the 24 hr period. Mean duration of episodes was 4.1 min for DR, 6.2 min for SWS and 3.3 min for REM. Sleep cycles (SC) duration was 13.1 min. Near 80% of the SC were nocturnal. Analysis of variance showed a significant difference between diurnal and nocturnal duration of SC (day less than night), as well as between day-time and night-time duration of DR (day greater than night), SWS (day less than night) and REM (day less than night). A strong negative correlation was also found between the mean duration of SC and the number of SC per day.

Animals↗
PubMed1983

Interactions in mixed monolayers between distearoyl-L-phosphatidylethanolamine, rod outer segment phosphatidylethanolamine and all-trans retinal. Effect of pH.

The interactions in mixed monolayers between distearoyl-L-phosphatidylethanolamine, natural phosphatidylethanolamine purified from bovine rod outer segments and all-trans retinal have been studied at the nitrogen/water interface at 21.0 +/- 0.5 degrees C. Seven mixtures of each phospholipid with all-trans retinal, covering the whole range of molar fractions, were studied. The monolayers were spread on a 1 X 10(-3) M phosphate buffer subphase at three different pH values, 5.5, 7.1 and 8.2. The results for the two series of mixtures are strikingly different. The surface phase rule shows that all-trans retinal is miscible with the natural phospholipid at the interface. Small, negative deviations with respect to the additivity rule are observed in this case. The excess free energies of mixing were also calculated as a function of concentration for this system at four different surface pressures, 5, 7, 10 and 13 mN X m-1. They are negative for the four surface pressures considered and symmetrical with respect to the mole fraction. On the other hand, when distearoyl-L-phosphatidylethanolamine is mixed with all-trans retinal, the components are no longer miscible at the interface. This marked difference in behaviour between the two lipids reflects the importance of hydrophobic interactions in the mixed monolayers of phospholipids with retinals. Furthermore, for the two series of mixtures, the surface pressure isotherms do not show any significant shift when the subphase pH is changed from 5.5 to 8.2. This behaviour raises questions about the formation of a Schiff base between phosphatidylethanolamine and retinal at the interface. It is suggested that, owing to the nature of the disk membranes, such an effect would also be observed in vivo. The possible implications of this are discussed, particularly with respect to questions pertaining to the stability of the retinal chromophore.

Animals↗
PubMed1983

Beyond decentralization: the evolution of population distribution in England and Wales, 1961-1981.

"Using preliminary figures from the 1981 Census, this paper details recent population shifts at a variety of areal scales in England and Wales. It compares trends in the 1971-1981 period with those in the previous decade and assesses the relative contributions of net migration and natural change. Within its broad descriptive objectives, the paper considers whether England and Wales has kept abreast of patterns of counter-urbanization that have been claimed for other industrialized nations." The authors propose some definitions for various terms, including decentralization, deconcentration, and counter-urbanization. "The conclusion is drawn that even if the postulated international continuum of changes ranging from urbanization through to counter-urbanization is valid, the limited geographical size of England and Wales will preclude this country from reaching the final stages of such a model. Finally, some policy implications which stem from the recent population redistributions are introduced and some themes for future research are considered."

Demography↗
PubMedDate not supplied

The electrical and spectroscopic properties of planar asymmetrical membranes incorporating chlorophyll a and plastoquinone-9. Influence of surface charges on electron transfer.

We studied the influence of surface charges on the efficiencies of electron transfer between a donor molecule, chlorophyll a (Chla), and an acceptor molecule, plastoquinone-9 (PQ-9), asymmetrically incorporated into a phospholipid matrix built from phosphatidylethanolamine, phosphatidylserine, and dimethyldistearylammonium bromide. Membrane conductance and capacitance measurements, as well as fluorescence emission experiments, were performed on bilayers containing positive or negative surface charges. The conductance of the bilayers showed important increases upon illumination of the Chla, this effect being observed only when both the donor and the acceptor molecules were present within the bilayer. This suggested that an electron transfer between Chla and PQ-9 occurred. The same kind of behaviour was observed with the membrane capacitance, but the amplitude of the effect was smaller. The results showed that an electric field gradient favorably oriented to promote electron transfer from Chla to PQ-9 maximized the electron transfer between these two molecules. However, both the membrane resistance and capacitance were permanently modified when illumination was stopped. On the other hand, the fluorescence results showed that for the range of surface charges covered, the position of the maximum of absorption was found unchanged around 675 nm and the intensity of fluorescence was almost constant, of the order of 7 x 10(6)-8 x 10(6) photons.s-1. This suggested that Chla was embedded as microdomains within the bilayer. The results presented here were also compared with what is known on the organization of the donor and acceptor molecules within the reaction centres of photosynthetic bacteria.

Chlorophyll↗
PubMedDate not supplied

Characterization of drug disposition and dosing using bioelectrical impedance.

Bioelectrical impedance analysis (BIA) yields accurate, safe and non-invasive estimates of body composition in humans. Pharmacokinetic characterization of drugs represents the body as a series of non-physiologic compartments. We evaluated the utility of BIA in the pharmacokinetic characterization and dosing of water soluble drugs. Serial serum concentrations of gentamicin (G) in 30 hospitalized adults, and theophylline (T), in 15 normal adult males were obtained over a dosing interval after an 8h fast, and analyzed in duplicate by enzyme-mediated immunoassay technique. BIA was performed serially in duplicate during the same time period using a fixed frequency (50kHz, 800 microA) current-injection 4-electrode plethysmograph. Multiple regression techniques were used to develop descriptive models of pharmacokinetic parameters which yielded equations with p-values < 0.03 and coefficients of variation < 20% accounting for > 85% of the pharmacokinetic variability. The G models were then tested in 20 critically ill adults at steady state by serum concentration measurement (criterion standard) and BIA. BIA predictive equations yielded pharmacokinetic parameters not different (by paired t-tests) than those derived by serum concentration measurement. While BIA is an innovative approach to the non-invasive characterization water soluble drugs, further testing with variable frequency BIA under perturbed conditions is warranted.

Adult↗