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Biomedical subjects

M Bourque

Publications and source records attributed to M Bourque.

At least 19 recordsLinked to original sources
PubMed1997

Comparing SNOMED and ICPC retrieval accuracies using relational database models.

While SNOMED International has been generally accepted by the international community of pathologists, its use for primary and secondary care remains limited. This can probably be attributed to the coding complexity of clinical concepts into this multiaxial postcoordinated nomenclature. The SNOMED editors propose the use of multiple codes (aggregates) for any nuanced clinical concept, thus allowing alternative rigorous representations of the concept with SNOMED codes. Some classification critics argue whether such redundant coding precludes precise retrieval of data. This research was initiated to compare the retrieval accuracies of a relational database using a simplified model of SNOMED against a classification-based model. SNOMED-based queries showed improvement over ICPC-based queries, regardless of the use of SNOMED cross-references. The addition of the latter significantly improved the queries sensitivity and false negative rate. In conclusion, the authors recommend using aggregates of SNOMED codes in relational database designs over classification-based designs in order to improve retrieval accuracy.

Classification↗
PubMed1991

Insulin-like growth factor II/mannose-6-phosphate receptors are transiently increased in the rat distal intestinal epithelium after resection.

The levels of insulin-like growth factor II/mannose-6-phosphate (IGF-II/Man-6-P) receptor and the insulin-like growth factor I (IGF-I) receptor were measured in the intestinal epithelium after 50% resection of the small intestine. Controls were either pair-fed to match the reduced food intake of the resected group or fed ad libitum. [125I]IGF-II binding was transiently increased 2-fold in the distal segment of the small intestine 3 days after resection compared with the pair-fed control. Receptor levels increased from 2.60 nmol/mg protein (pair-fed) to 4.63 nmol/mg protein (resected; p less than 0.001) with no significant change in affinity of IGF-II binding (Kd = 11.2 vs. 9.8 nmol/l). The increase in IGF-II/Man-6-P receptors coincided with increased activity of thymidine kinase in the distal intestinal segment after the resection. [125I]IGF-I binding remained unchanged after the resection. However, the decreased food intake of the pair-fed and resected groups caused a 2-fold increase in the amount of IGF-I receptors (0.18 nmol/mg protein; p less than 0.001) compared with the control fed ad libitum (0.08 nmol/mg protein). IGF-II/Man-6-P receptors were only moderately increased during restricted food intake (2.60 vs. 1.78 nmol/mg protein; p less than 0.005). These results suggest that the IGF-II/Man-6-P receptor may play a role in the adaptive regenerative response of the intestinal epithelium.

Animals↗
PubMed1987

Plasma levels of retinol in cancer patients supplemented with retinol.

Previous studies have indicated that plasma levels of retinol are decreased in some cancer patients and that lower levels of retinol could be associated with a poor response to chemotherapy. This pilot study was conducted to determine whether it is possible to increase plasma levels of retinol in cancer patients by supplementation with retinol. Plasma levels of retinol were measured by high-performance liquid chromatography in 46 patients treated with chemotherapy for various malignancies and in 43 control individuals; cancer patients were supplemented orally either with 25,000 or 50,000 IU of retinol daily during up to 3 months. Initial levels of retinol were lower in cancer patients than in the control group; the decrease was significant in women with liver metastases but not in men. Women supplemented with 25,000 IU had a significant increase of their retinol levels after 1 month but this effect was not maintained during continued supplementation; in women receiving 50,000 IU daily, a sustained increase in retinol level was maintained during the 3 months of supplementation. In men, a similar trend was produced by the supplementation but the increases were not significant. Retinol levels decreased to initial levels within 1 month of discontinuation of supplementation, indicating the need for continuous supplementation.

Adult↗
PubMed1985

Orthostatic hypotension: a posture-induced hyperdopaminergic state.

To explore the role of dopaminergic mechanisms in orthostatic hypotension we compared the postural responses of 20 such patients to those of a control group by radioenzymatic determination of free and sulfated catecholamines and related indices. Patients with orthostatic hypotension, unlike control subjects, experienced an increase in total plasma dopamine (DA) (free + sulfate) in response to upright posture (p less than 0.01). Of the 20 patients with orthostatic hypotension, 16 were normo- or hyperadrenergic with normal basal and posture-responsive or hyperresponsive plasma free and total norepinephrine (NE). The other 4 were hypoadrenergic with low basal and posture-unresponsive NE. Hypoadrenergic patients had, in the upright position, no increase in pulse rate and more severe hypotension, less diuresis and natriuresis, lower urinary free and total DA, lower total NE excretion, and higher plasma and urinary total DA:total NE ratio than normo- or hyperadrenergic patients or control subjects. Normo- or hyperadrenergic patients had higher PRA and plasma aldosterone in the upright position than hypoadrenergic patients or control subjects (all p less than 0.05). We suggest that an excessive increase in free DA occurs in response to upright posture, perhaps representing a compensatory reaction of the remaining autonomic nervous system to an excessive fall in blood pressure. The free dopamine may be biologically active but it is so rapidly sulfoconjugated that it can be detected only as DA sulfate. These findings, combined with reports of orthostatic hypotension precipitated by administration of dopaminomimetic drugs and relieved by administration of dopaminergic antagonists, are consistent with the interpretation that excessive DA release may perpetuate, by its vasodilating and natriuretic action, the orthostatic hypotension.

Adult↗
PubMed1984

Serologic studies on brucellosis, leptospirosis and tularemia in moose (Alces alces) in Quebec.

Blood samples were obtained from 208 moose in La Vérendrye and Matane Reserves and in Laurentides Park, Quebec, Canada. Sera were tested for antibodies to Brucella abortus, Leptospira interrogans serovar ballum, canicola, grippotyphosa, hardjo, icterohaemorrhagiae and pomona, and Francisella tularensis. Fifteen sera contained evidence of prior exposure to F. tularensis. Only one animal was a seroreactor to L. interrogans serovar grippotyphosa and none of them had antibodies to B. abortus.

Animals↗
PubMed1984

Catecholamine sulfates and platelet phenolsulfotransferase activity in essential hypertension.

Because of high plasma concentrations of conjugated catecholamines and their unknown relationship to hypertension, we determined those conjugates more specifically as catecholamine sulfates together with the sulfoconjugating enzyme-phenolsulfotransferase activity in platelets of 62 patients with essential hypertension and 32 normal controls. Our results indicated: (1) that the pool of total (free and sulfated) catecholamines (dopamine, norepinephrine, and epinephrine) is higher (because of an increase in dopamine sulfate levels) but the degree of epinephrine conjugation is lower in patients with essential hypertension compared with controls; (2) that norepinephrine sulfate levels rise with age in both groups, but the increase in free norepinephrine with age observed in controls was not observed in patients with essential hypertension; and (3) that catecholamine conjugates were found to be exclusively sulfates and platelet phenolsulfotransferase activity was not different in both groups. Platelet phenolsulfotransferase activity was, however, positively correlated with plasma norepinephrine sulfate levels, and the degree of sulfoconjugation of norepinephrine was positively correlated with that of dopamine in controls but not in patients with essential hypertension. These abnormalities occurring in essential hypertension in the absence of intergroup differences in platelet phenolsulfotransferase activity suggest that the enzyme is either not a good marker of the overall activity or that other factors account for the observed differences. Thus, additional determinants of the process of generation and degradation of sulfoconjugated catecholamines, some of which may be more stable markers of sympathetic activity than free catecholamines, need to be explored.

Adult↗
PubMed1983

[Peripheral vascular effects of metoprolol, pindolol and propranolol in hypertensive patients].

Hemodynamic parameters, after administration of three different beta-blockers, were measured in fifteen hypertensive, and five normotensive, subjects. The non-invasive hemodynamic measurements were made prior to drug administration, after the first dose, and after prolonged treatment with either: metoprolol (M) 100 mg b.i.d., propranolol (Pr) 80 mg b.i.d., or pindolol (P) 10 mg b.i.d. With the parameters of blood pressure (B.P.), pulse rate (H.R.), blood flow in the leg at rest were determined with the plethysmographic impedance technique; venous compliance (V.C.), and flow in the leg after reactional hyperemia (F.R.H.) were evaluated by the mercury gauge technique. The pneumoplethysmographic technique was used to measure digital flow (D.F.). During administration of metoprolol, the B.P. and H.R. decreased significantly in the first few hours, and remained so during the prolonged treatment period of 4 weeks; the other parameters did not change significantly. Propranolol, after short-term treatment, decreased H.R. and blood flow in the leg at rest. Also, modifications in the venous compliance occurred but are difficult to interpret. After administration of pindolol, except for a decrease in H.R. and reactional hyperemia that occurred during the 2nd hour, no significant changes occurred in the other parameters. The digital flow showed non-significant variations. These preliminary results demonstrate that the changes registered through non-invasive techniques, although very small, affect pindolol less than metoprolol or propranolol.

Adrenergic beta-Antagonists↗
PubMed1982

The hemodynamic relevance of free and conjugated dopamine in pheochromocytoma.

Two patients with adrenomedullary hypersecretion (confirmed pheochromocytoma and adrenomedullary hyperplasia) presented 15 spontaneous crises associated with hypertension or hypotension with or without tachycardia. Correlation coefficients calculated between extreme values of pulse rates and of systolic and diastolic blood pressures on the one hand and plasma free and conjugated norepinephrine, epinephrine, and dopamine (DA) sampled at the height of the crises on the other, showed no relationships between free or conjugated norepinephrine or epinephrine and blood pressure or pulse rate. However, plasma conjugated DA was negatively correlated with systolic blood pressures (P less than 0.02) and diastolic blood pressures (P less than 0.03) and free plasma DA was negatively correlated with pulse rates (P less than 0.001). These data suggest that the extremely high circulating level of conjugated DA in pheochromocytoma may, in the presence of high circulating conjugated norepinephrine and possibly high alpha-adrenergic receptor occupancy, decrease blood pressure by its predominant action on dopaminergic receptors while elevated free DA may decrease the tendency to tachycardia, possibly by lowering the venous return.

Adrenal Gland Neoplasms↗
PubMed1976

Synergism of cefazolin-gentamicin against enterococci.

A miniaturized technique for detecting antibiotic synergy by using microliter volumes was perfected. With this microtiter serial dilution method, the effect of the previously untried combination of cefazolin and gentamicin on 10 strains of enterococci was evaluated. At clinically achievable concentrations, the combination of cefazolin and gentamicin was found to be synergistic against all 10 strains when the data were plotted in the form of an isobologram. These results were compared with the conventional method of detecting synergy in vitro, namely, the determination of the rate of killing of the microorganisms with the antibiotics, singly and in combination. Similar results were also observed. These findings indicate that the microtiter serial dilution technique is a useful method for the routine determination of drug synergy. Moreover, in a patient with penicillin hypersensitivity and enterococcal infection, the combination of cefazolin and gentamicin should be considered for possible therapy.

Cefazolin↗