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Biomedical subjects

D Gagnon

Publications and source records attributed to D Gagnon.

At least 55 records · Page 3Linked to original sources
PubMed1992

Significant reduction of peritonitis rate by the use of Twin-bag system in a Canadian regional CAPD program.

In a regional CAPD program in Northern Alberta, Canada, the peritonitis rates among patients undergoing CAPD treatment were quite high: 1/8.3 and 1/7.4 per patient month from a population of 75 and 76 patients in 1989 and 1990 respectively. Our patient population is comprised of different ethnic groups, separated widely from the dialysis centre; over half of them are above the age of 60 years. As it is not possible to change the patient characteristics in our centre, we switched to the Twin-bag disconnect system in 83 out of a total of 103 patients in 1991. With this change our overall peritonitis rate has significantly improved to 1/14 per patient months and 1/17 per patient months in patients using the Twin-bag system. This improvement in the peritonitis rate has occurred without any change in our patient characteristics. We find the improvement in our peritonitis rate is due to the use of the new Twin-bag system, which provides total disconnection with no spikes and thereby reduces peritonitis due to touch contamination.

Humans↗
PubMed1991

Technetium-99m sestamibi tomography in patients with spontaneous chest pain: correlations with clinical, electrocardiographic and angiographic findings.

The sensitivity and specificity of technetium-99m hexakis-2-methoxy-2-isobutyl-isonitrile (sestamibi) single-photon emission computed tomographic (SPECT) imaging for the diagnosis of coronary artery disease were studied in 45 patients admitted to the hospital for clinical suspicion of unstable angina. Only patients without prior myocardial infarction were included and all patients had technetium-99m sestamibi injection and a 12-lead electrocardiogram (ECG) during and less than or equal to 4 h after an episode of chest pain. Coronary angiography performed in all patients during hospitalization showed significant coronary artery disease (greater than or equal to 50% luminal diameter reduction) in 26 of the 45 patients. The SPECT studies obtained after injection of technetium-99m sestamibi during an episode of spontaneous chest pain showed a sensitivity of 96% for the detection of coronary artery disease; the 12-lead ECG obtained at the time of the injection had a sensitivity of 35%. With the patient in the pain-free state, respective sensitivity values were 65% and 38%. Specificity for the radionuclide study was 79% during pain and 84% in the pain-free state; for the ECG, it was 74% both during and between episodes of pain. The site of the perfusion defect corresponded to the most severe coronary artery lesion in 88% of patients. The severity of the perfusion defect correlated with the extent of coronary artery disease: the defect score was 5.3 +/- 3.3 with one-vessel disease, 4.9 +/- 2.8 with two-vessel disease and 10.5 +/- 5.0 with three-vessel disease (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

High-normal blood pressure progression to hypertension in the Framingham Heart Study.

This study sought to determine if individuals with high-normal blood pressure (diastolic blood pressure of 85-89 mm Hg) progress to hypertension more frequently than those with normal blood pressure (diastolic blood pressure less than 85 mm Hg), thus advancing to a higher cardiovascular risk category. Individuals from the Framingham Heart Study were placed in normal and high-normal blood pressure categories and followed for 26 years for the development of hypertension. With hypertension defined as a diastolic blood pressure of 95 mm Hg or greater or the initiation of antihypertensive therapy, 23.6% of men and 36.2% of women with normal blood pressure developed hypertension compared with 54.2% of men and 60.6% of women with high-normal blood pressure. The relative risk for the development of hypertension associated with high-normal blood pressure was 2.25 for men (95% confidence interval [CI], 1.8-2.8; p less than 0.0001) and 1.89 for women (95% CI, 1.5-2.3; p less than 0.0001). The age-adjusted relative risks estimated by the proportional hazards model were 3.36 for men and 3.37 for women (p less than 0.001). Among those risk factors examined, baseline systolic and diastolic blood pressure, Metropolitan relative weight, and change in weight over time were significant predictors of future hypertension in men and women whose initial blood pressure was normal. For men with high-normal blood pressure, systolic blood pressure and change in weight were identified as risk factors for future hypertension. These results indicate that the probability of individuals with blood pressure in the high-normal range developing hypertension is twofold to threefold higher than in those with normal blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

EMG power spectrum as a measure of muscular fatigue at different levels of contraction.

The shift in the power spectrum resulting from a 5-7 min fatigue-inducing effort followed by a 1-2 min recovery period of two elbow flexors, the biceps brachii (BB) and the brachio-radialis (BR), was assessed using two variables, the mean frequency Fm and the median or central frequency Fmd. These two variables were calculated in pre- and post-fatigue conditions and following a brief recovery, at four levels, namely 20, 40, 60 and 80 per cent of maximum voluntary contraction (MVC). These were taken from a ramped isometric effort that is from 0 to 100 per cent MVC. The EMG activity of the two flexors was recorded with bipolar surface electrodes from a group of ten volunteers. Following muscle fatigue, induced with a maintained 60 per cent MVC isometric contraction, a statistically significant (p less than 0.05) shift towards the lower frequencies was observed for both Fm and Fmd for both muscles. Following a brief recovery, a shift towards the pre-fatigue higher frequencies was statistically significant (p less than 0.05). These two synergists responded to muscle fatigue and recovery similarly, as they both demonstrated parallel shifts in power spectrum. The power spectrum is consequently a reliable measure of muscular fatigue. It is also complementary to the net articular moment results.

Adult↗
PubMed1989

Long-term tocolysis with intravenous magnesium sulfate.

Although the tocolytic effect of magnesium sulfate is well known, it has generally been used for this purpose for only brief periods. In this study, we administered intravenous magnesium sulfate tocolysis, either alone or in combination with other tocolytics, to 111 women as follows: 1) 60 (54%) received the drug for 3 or fewer days (short-term group); 2) 29 (26%) received the drug for 3-10 days (intermediate group); and 3) 22 (20%) received the drug for 10 days or longer (long-term group). Side effects (ileus and/or constipation, visual blurring, headache) were more common in the intermediate and long-term groups, but no life-threatening complications were seen. The drug was discontinued because of side effects in 7% of the patients in each group. We believe our data indicate that there need be no time limit and that magnesium sulfate tocolysis may be continued as clinically indicated.

Delivery, Obstetric↗
PubMed1989

Carcinoma of the lung. Evaluation of satellite nodules as a factor influencing prognosis after resection.

Satellite nodules are considered to be predictive of poor prognosis in breast cancer and in melanoma. In lung cancer, there is no information as to their definition, prevalence, or implication as a prognosis factor of survival after resection. Over the past 18 years (1969 to 1987), 84 patients underwent pulmonary resection for primary lung cancer accompanied by satellite nodules. These nodules were defined as well-circumscribed accessory carcinoma foci clearly separated from the main tumor but with identical histologic characteristics. All were smaller than the primary carcinoma and most were located within the same lobe. Survival rates of patients with satellite nodules were compared to those of 1021 patients without satellite nodules who underwent resection during the same time interval. The 1-, 3-, and 5-year survival rates for all patients classified as having no satellite nodules were 78%, 54%, and 44%, respectively, and the median survival for the entire group was 30 months. In patients with satellite nodules, these survival rates were 60.9%, 32.7%, and 21.6%, respectively, with a median survival of 15 months. The deleterious effect of satellite nodules was more significant in patients with stage I disease (p = 0.0008) than in patients with stage II (p = 0.0354) or stage III (p = 0.0145) disease. Survival data obtained by comparison of satellite nodule status and histologic characteristics shows that 5-year survival figures are better for patients with no satellite nodules in both the squamous and the nonsquamous groups. This study demonstrates that satellite nodules associated with lung cancer are indicative of locally advanced and/or premetastatic disease. These patients should be included in the stage group IIIa of the TNM stage grouping classification.

Adult↗
PubMed1985

[Physical characteristics of stripping veins preserved at 4 degrees C and usable as artery substitutes].

The mechanical behavior of varicosis veins harvested during stripping and preserved at 4 degrees C has been investigated by measuring the compliance, the yield strain, the yield stress and the longitudinal Young's modulus. No relationship has been demonstrated between those parameters and external factors such as age, sex, storage duration and bacteremic contamination. The mechanical behavior of such veins is unpredictable. Therefore, it is mandatory to proceed through individual and non-destructive quality control tests to obtain a selection of grafts suitable for implantation. Moreover, implantation should be oriented towards patients who are able to visit the hospital frequently since the healing capacity of the venous homograft is unpredictable.

Arteries↗
PubMed1984

[Prostaglandins and thromboxanes].

Prostaglandins and thromboxanes are 20-carbon-atom-chain fatty acids which contain a cyclopentane or oxane nucleus respectively. They belong to a family of icosanoids whose main intracellular precursor is arachidonic acid. These icosanoids are synthetized in all tissues (except red cells). Enzymatic hydrolysis of the arachidonic acid of lipids is the first step of their biosynthesis. This step, which is limitative, is usually catalyzed by phospholipase A2 and may be indirectly inhibited by glucocorticoids. Once released, arachidonic acid is promptly transformed into an endoperoxide intermediary through the action of an enzymatic complex called "cyclooxygenase". This intermediary is the precursor of both prostaglandins and thromboxane. Non-steroidal antiinflammatory agents such as acetylsalicylic acid and indomethacin have an inhibitory action on cyclooxygenase. The mechanisms of action of prostaglandins and thromboxane are still poorly understood. In certain tissues (platelets, adipose cells) their effect seems to involve stimulation of adenyl-cyclase and/or guanyl-cyclase. In other tissues (smooth muscle) their biological action is associated with changes in transcellular flows of calcium. Prostaglandins and thromboxane have many biological properties. Their effects are local, as they are produced in small quantities and promptly metabolized. They act more often as cell function modulators than as essential mediators. The often conflicting biological actions of these icosanoids involve: a) smooth muscles (stimulation or relaxation of blood vessel, respiratory tract, digestive tract and genitourinary tract musculatures); b) platelets (induction or inhibition of aggregation); c) the inflammatory reaction; d) the cellular fluid and electrolyte transports; e) and certain metabolic functions (lipolysis, insulin release, renin release, mobilization of bone calcium...). The advances achieved over the last decade now provide some insight into the significance of the physiologic role of icosanoids. Several prostaglandins, as well as some of their analogues, are already being used as therapeutic agents. In the future, rational manipulation of dietary fatty acids and development of selective inhibitors can be expected to provide the necessary tools for better controlling the icosanoid system in medicine.

Animals↗
PubMed1984

Overworked and underpaid: on the nature of gender differences in personal entitlement.

This research investigated gender differences in feelings of personal entitlement with respect to monetary payment for work performed. Two experiments were conducted to test the hypothesis that women's internal standards of fair pay for their work are lower than men's and to examine possible causes of this difference. In Experiment 1, men and women were asked to pay themselves in a private situation what they thought was fair pay for a fixed amount of work. Social comparison information was varied. As predicted, women paid themselves less money than men in the absence, but not the presence, of social comparison information. In Experiment 2, men and women were asked to do as much work as they thought was fair for a fixed, prepaid, amount of money. Subjects believed that their work was either monitored or unmonitored. Women worked significantly longer, did more work, and did more correct work than men in both public and private work settings. Furthermore, women, but not men, worked longer when they believed their work was monitored than when they believed it was unmonitored. Possible explanations for these gender differences are discussed.

Employment↗
PubMed1980

Defibrinogenation as an alternative to heparinization in prolonged extracorporeal circulation.

Complications arising from difficulty controlled bleeding and thrombus formation during procedures which require extracorporeal circulation with heparin as anticoagulant motivate the search for better hemostasis and anticoagulant technology. An enzyme (Defibrase), having a specific interaction with fibrinopeptide A such as to cause fibrin depletion in a soluble form, has been proposed as an alternative to heparin. Defibrase, in contrast to heparin, does not affect blood platelet function. Heparin and Defibrase as anticoagulants were compared in 8 h perfusion studies using arterio-venous extracorporeal blood circuits in dogs; the circuitry included pumps, membrane oxygenators and filters serially. Thrombus formation, in the filters and the oxygenators as well as pathology of the perfused animal were investigated. The results suggest that defibrase-like enzymes have potential for enhanced control of hemorrhagic and thrombotic phenomena. Although impeded by a latency of several hours before the full anticoagulant properties are developed in vivo, it appears that enzymatically mediated defibrinogenation of blood may be a valuable alternative to heparinization in extracorporeal circulation procedures.

Animals↗