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Biomedical subjects

M Boucher

Publications and source records attributed to M Boucher.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Bioinversion of ibuprofen enantiomers after administration in dogs: estimation of a novel index.

This study compares the pharmacokinetics and bioinversion of two chemical forms of ibuprofen administered intravenously or orally. Dogs were given the free acid form of the S(+) isomer p.o. or i.v., or the racemate, as the free acid or sodium salt, p.o., in a cross-over design. The main kinetic parameters were calculated and formation and bioinversion curves plotted. The values of Cmax, Tmax and AUC were higher for the S(+) isomer. The percentage bioinversion averaged between 35-70% according to the form. This study proposes a new index for the calculation of bioinversion, independently of any i.v. administration, and confirms its self-limiting nature.

Animals↗
PubMedDate not supplied

Comparison of the effects of pentobarbital and chloralose on the cardiac rhythms of the dog in chronic atrio-ventricular heart block.

In the dog in chronic atrio-ventricular dissociation, pentobarbital at a dose of 25 mg/kg causes atrial tachycardia, but does not change the ventricular frequency. The vagolytic effect of pentobarbital explains this phenomenon. The pronounced vagal tonus seen in the Keith-Flack node, is not seen in the ventricle. Chloralose at a dose of 80 mg/kg i.v. does not alter atrial frequency but depresses ventricular frequency, in a significant way, for 40 min.

Animals↗
PubMedDate not supplied

Predictive value of amniotic-membrane cultures for the development of postcesarean endometritis.

This study assesses (1) the relationship between the bacteriology of amniotic-membrane cultures (AMCs) obtained at the time of primary cesarean section and the subsequent postoperative course of afebrile, laboring patients whose membranes ruptured greater than or equal to 4 hr before delivery and (2) the impact of perioperative antibiotics on this relationship. Therapy with perioperative antibiotics was begun after the cord was clamped and the membrane specimen was obtained for culture. Specimens for AMC were obtained from 127 patients; 62 received placebo and 65 received perioperative antibiotics. In spite of the homogeneity of the patients' clinical risk factors, their AMCs demonstrated considerable variation in the degree of bacterial contamination present at the time of cesarean section. The presence of no growth or of low-virulence isolates only in the AMC usually was associated with a benign postoperative course, and therapy with perioperative antibiotics did not significantly decrease the incidence of endometritis associated with these AMC patterns. On the other hand, the presence of a mixture of high- and low-virulence organisms in the AMC or of high-virulence anaerobes only--more specifically, gram-negative anaerobes--was predictive of subsequent postcesarean endometritis only for patients who did not receive perioperative antibiotics, and therapy significantly decreased the incidence of endometritis associated with these AMC patterns. In conclusion, the correlation between specific bacteriologic patterns found in the AMC and the subsequent development of endometritis for patients who did not receive prophylactic antibiotics was better than the correlation based on clinical risk factors alone.

Adolescent↗
PubMedDate not supplied

Double loop receiver coil for MR imaging at 0.15 T.

A receiver coil of a cross-coupled, double loop geometry has been developed. This coil has a higher signal-to-noise (S/N) ratio and more homogeneous signal intensity at increasing depth than a conventional surface coil. Improvements in S/N of 51-256% compared with the commercial half-saddle body coil have been demonstrated in a 0.15 T resistive instrument. The new coil permits reduction in pixel volume using higher field gradients and thinner slices or time savings using fewer signal averages. The double loop coil provided higher S/N for lumbar spine imaging than an oval surface coil. Limitations of this type of coil design are increased sensitivity to respiratory motion artifacts and limitation of the size of the subject that may be imaged. Using the double loop coil, the capability of our instrument to image the heart, pelvis, hip, and shoulder has been substantially improved.

Equipment Design↗
PubMedDate not supplied

Comparison of prizidilol, a new antihypertensive drug with combined arteriolar vasodilator and beta-adrenoceptor blocking actions, with hydralazine and propranolol in conscious dogs with chronic atrioventricular block.

The effects of prizidilol, a novel antihypertensive agent with vasodilator and beta-adrenoceptor blocking actions, were compared with those of hydralazine and propranolol in conscious dogs with chronic atrioventricular block. Prizidilol significantly increased atrial rate, mainly through reflex reduction of atrial vagal tone in response to its hypotensive effect. Hydralazine also significantly raised atrial rate, while propranolol did not affect it. Prior administration of pindolol, which raised atrial rate to a degree comparable to that achieved with prizidilol and hydralazine, entirely suppressed the atrial tachycardiac effects of both drugs. Prizidilol did not affect ventricular rate on average, whereas hydralazine raised it and propranolol lowered it, both significantly. In some dogs, prizidilol raised ventricular rate like hydralazine; in others, it lowered it like propranolol. In both cases, variation was related to basal ventricular rate. The pattern of these effects was the same as that observed with pindolol. Prior treatment with pindolol almost suppressed the ventricular chronotropic effects of prizidilol, apparently through beta-adrenoceptor blockade.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Propafenone in the conscious dog with chronic atrioventricular block: mechanisms of chronotropic cardiac effects and plasma concentration-response relationships.

The chronotropic effects of propafenone were studied in the conscious dog with chronic atrioventricular block. Propafenone at 0.5-4 mg/kg, i.e., at plasma levels within the assumed therapeutic range, dose relatedly raises atrial rate. This effect falls off and bradycardia is even observed at 0.5 and 1 mg/kg once plasma levels have dropped below 330 +/- 31 ng/ml. After atropine, propafenone (2 mg/kg) lowers atrial rate, after propranolol it raises it, and after pindolol it does not modify it. Propafenone dose relatedly raises ventricular rate, although again this effect subsequently reverses at 4 mg/kg. After atropine, propranolol, and pindolol, propafenone (2 mg/kg) instead of initially raising ventricular rate lowers it lastingly. It initially lowers mean blood pressure according to dose. At 2 mg/kg neither this effect nor the plasma levels are modified by the antagonists. The beta-blocking potency is 1/40th that of propranolol as determined against isoproterenol-induced cardioacceleration. These results show that the atrial cardioacceleration due to propafenone results from direct and reflex vagolytic action and that the bradycardia at low plasma levels (buffered by the vagolytic effect at high levels) seems due to its membrane-stabilizing action. They also show that the initial ventricular cardioacceleration is a reflex response to its hypotensive effect, whereas the ventricular bradycardia at high doses is attributable to its membrane-stabilizing action and its albeit weak beta-blocking action.

Animals↗
PubMedDate not supplied

Comparative effects of disopyramide and its mono-N-dealkylated metabolite in conscious dogs with chronic atrioventricular block: plasma concentration-response relationships.

In animals and humans, the antiarrhythmic agent disopyramide is primarily metabolized by mono-N-dealkylation. The effects of disopyramide and its N-dealkylated metabolite (MND) were investigated in 13 conscious dogs with chronic atrioventricular (A-V) block and implanted atrial pacing electrodes. Our data clearly show that both compounds used within the therapeutic plasma level range induced lengthening of the atrial effective refractory period (AERP) as reflected by the diminution of the maximal atrial frequency determined by pacing. However, at equivalent drug plasma concentrations, disopyramide induced a more marked decrease (1.2-1.7 times) in the maximal atrial frequency than did its metabolite. Both compounds increased mean arterial pressure (MAP) and atrial rate and decreased ventricular rate, but the effects on MAP and atrial rate were more marked with disopyramide than with MND. Thus, with regard to these cardiovascular parameters, the parent drug and MND possess distinct pharmacodynamic profiles, which may in part be related to their respective vagolytic power.

Animals↗
PubMedDate not supplied

Polytetrafluoroethylene gas intoxication in broiler chickens.

A poultry research facility that housed 2400 Peterson x Hubbard cross broilers (48 pens of 50 chicks each) experienced 4% mortality within 24 hr of chick placement. Mortality started within 4 hr of placement, and within 72 hr, cumulative mortality had reached 52%. Mild dyspnea was the only clinical sign noted in some chicks prior to death. The primary gross lesion noted in the chicks submitted was moderate to severe pulmonary congestion. The lungs of four of these chicks sank in formalin, and blood-tinged fluid was noted in the mouth and nares of two chicks. The microscopic lesions noted in the affected chicks were moderate to severe pulmonary edema and congestion. The diagnosis indicated to the submitter was that pulmonary edema caused by exposure to an unidentified noxious gas caused the death of the chicks. The poultry house environment was tested for sulfur dioxide, oxides of nitrogen, carbon monoxide, carbon dioxide, and volatile organic compounds (as produced by combustion engines); all tests were negative for significant levels of these compounds. A second broiler flock was placed in the same facility and the mortality at 6 wk was 11%, which was greater than the 2.5%-4.7% mortality seen in the previous four flocks on the farm. Further investigation revealed that the only change in management practice in this facility prior to the onset of the severe mortality problem was the replacement of 48 heat lamp bulbs (one for each pen). The new heat lamp bulbs were polytetrafluoroethylene (PTFE) coated. PTFE gas intoxication has been reported in several exotic avian species, but this intoxication has not been previously reported in a poultry flock.

Animals↗
PubMedDate not supplied

[The pertinence of microscopic analysis of the urine as a diagnostic test for asymptomatic bacteriuria in pregnancy].

The genito-urinary tract is the most frequent site of infection during pregnancy. Asymptomatic bacteriuria is found in 2 to 12% of the obstetrical population. The importance of its detection is underlined by the fact that 20 to 40% of untreated cases will present acute pyelonephritis. Our study's first aim was determining the incidence of asymptomatic bacteriuria in our population. Our results show an incidence of 3.9%. Second, routine mandatory prenatal laboratory examinations include urinalysis and urine culture. Considering the fact that we already do a routine culture, we questioned the pertinence of the microscopic part of urinalysis for screening asymptomatic bacteriuria. Our study has shown that no amount of erythrocytes, leucocytes, bacteria, pus or combination thereof has sufficient sensitivity and/or specificity to be used for screening. We thus conclude that in our context of budget restrictions, the microscopic analysis of urine should be abandoned as a routine test. The biochemical part of urinalysis could be done easily with dipsticks at a lower cost. Urine culture remains the gold standard for detection of asymptomatic bacteriuria.

Adult↗
PubMedDate not supplied

[Use of local cobalt therapy in peripheral neuropathies associated with chronic lymphopathies (lymphoses). 2 cases with histo-immunologic and ultrastructural records].

In two cases of peripheral neuropathy, associated with a chronic lymphopathy, cobalt therapy to the lower limbs provided considerable relief of pain, with partial motor recovery. The disappearance after cobalt therapy of the lymphoid infiltrate of the peripheral nerve leads to discussion of the pathogeni role of this infiltrate. Immunofluorescent and electron microscopic studies form the basis of a discussion of the mechanism of involvement of the peripheral nerve non-secreting lymphopathies (chronic lymphoid leukaemia) and in secreting lymphopathies (Waldenström's disease).

Aged↗