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Biomedical subjects

D Gagnon

Publications and source records attributed to D Gagnon.

At least 19 recordsLinked to original sources
PubMed1995

Protective effect of fruits and vegetables on development of stroke in men.

OBJECTIVE: To examine the effect of fruit and vegetable intake on risk of stroke among middle-aged men over 20 years of follow-up. DESIGN: Cohort. SETTING: The Framingham Study, a population-based longitudinal study. PARTICIPANTS: All 832 men, aged 45 through 65 years, who were free of cardiovascular disease at baseline (1966 through 1969). MEASUREMENTS AND DATA ANALYSIS: The diet of each subject was assessed at baseline by a single 24-hour recall. The estimated total number of servings per day of fruits and vegetables was the exposure variable for this analysis. Using Kaplan-Meier survival analysis, we examined age-adjusted cumulative incidence of stroke by quintile of servings per day. To adjust for multiple covariates, we used proportional hazards regression to calculate the relative risk (RR) of stroke for each increment of three servings per day. MAIN OUTCOME MEASURE: Incidence of completed strokes and transient ischemic attacks. RESULTS: At baseline, the mean (+/- SD) number of fruit and vegetable servings per day was 5.1 (+/- 2.8). During follow-up there were 97 incident strokes, including 73 completed strokes and 24 transient ischemic attacks. Age-adjusted risk of stroke decreased across increasing quintile of servings per day (log rank P for trend, .01). Age-adjusted RR for all stroke, including transient ischemic attack, was 0.78 (95% confidence interval [Cl], 0.62 to 0.98) for each increase of three servings per day. For completed stroke the RR was 0.74 (95% Cl, 0.57 to 0.96); for completed stroke of ischemic origin the RR was 0.76 (95% Cl, 0.57 to 1.02); and for completed stroke of hemorrhagic origin, 0.49 (95% Cl, 0.25 to 0.95). Adjustment for body mass index, cigarette smoking, glucose intolerance, physical activity, blood pressure, serum cholesterol, and intake of energy, ethanol, and fat did not materially change the results. CONCLUSION: Intake of fruits and vegetables may protect against development of stroke in men.

Cerebrovascular Disorders↗
PubMed1995

Structure-function studies of motilin analogues.

Over 100 motilin fragments and analogues, including monosubstituted C-terminal-deleted analogues, conformationally restricted analogues, analogues with peptide bond isoteres (CH2-NH), and N-terminal fragments adjunct to an amphiphilic helix, were synthesized by solid-phase methodology, purified by reverse-phase HPLC, and assayed in vitro in a muscle strip bioassay (rabbit duodenum) and in a radioligand binding assay on crude membrane extracts from smooth muscle (rabbit antrum). The data suggest the existence of three distinct regions involved in the interaction of motilin with its receptor: the N-terminal region (amino acids 1-7) constitutes the minimal basic unit of binding and activity; the transition region (amino acidsa 8-9) links the N-terminal and C-terminal regions; and the C-terminal region (amino acids 10-22) forms an alpha-helix that stabilizes the interaction of the N-terminal residues at the active site.

Amino Acid Sequence↗
PubMed1994

Motilin synthetic analogues and motilin receptor antagonists.

While studying the structure-activity characteristics of motilin with motilin synthetic analogues, two compounds, motilin 1-12 [CH2 NH]3-4 and motilin 1-12 [CH2 NH]10-11, showed high affinity for the motilin receptor combined to a weak contractile activity. The following data suggest that motilin 1-12 [CH2 NH]10-11 is a potent motilin receptor antagonist. It showed a high affinity for the motilin receptor present on membranes of rabbit antrum (pIC50: 8.24 +/- 0.08 for the analogue vs 8.96 +/- 0.02 for the native peptide). When tested in vitro on strips of rabbit duodenum, the dose-response curve to motilin 1-22 was displaced to the right with motilin 1-12 [CH2 NH]10-11 (pIC50: 8.91 +/- 0.06 in presence of saline versus 7.19 +/- 0.40 with the analogue). However, when injected i.v. in dogs, motilin 1-12 [CH2 NH]10-11 was undetectable in the peripheral blood, suggesting enzymatic degradation precluding its use in vivo.

Animals↗
PubMed1994

Occupational allergy after exposure to caddis flies at a hydroelectric power plant.

A cross sectional survey was conducted in a hydroelectric power plant in which the workforce was exposed to large numbers of caddis flies. 28 of 57 employees participated. About 50% of the participants reported work related eye, nose, and sinus symptoms and wheezing. Working in locations with greater exposure to caddis flies was significantly associated with work related symptoms. 17 workers (61%) were skin prick positive to a laboratory prepared caddis fly antigen (LCFA) made from the remains of caddis flies present in the plant and 11 (39%) had positive reactions to a commercial caddis fly antigen (CCFA). Workers stationed in heavily exposed areas were 3.7 times as likely to have a positive response to the LCFA (p = 0.009) and 5.3 times as likely to have a positive response to the CCFA (p = 0.036). 13 (46%) of survey respondents reported three or more work related symptoms. 10 (91%) CCFA positive workers reported three or more work related symptoms. Pulmonary function studies revealed slight, but not significantly decreased forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and FEV1/FVC ratios in workers who were skin test positive to either caddis fly preparation when compared with those who were negative. One worker who was skin test positive to both antigens had a cross shift fall in FEV1 of 20% predicted. Occupational allergy to caddis flies proved to be a significant health problem at this work site.

Adult↗
PubMed1992

N-terminal portion of motilin determines its biological activity.

This study aimed to identify the portion of the 22 amino acid sequence of motilin responsible for the biological activity of the peptide. The contraction of rabbit duodenal muscle in vitro was measured when exposed to synthetic fragments of motilin corresponding to various sequences of the C- or N-terminal portions of the molecule. Fragments 2-22 or 3-22 (where the initial amino acids of the N-terminal ending were removed) were more than 1000 times less potent than the native molecule 1-22. Fragment 1-9 (where the last 13 amino acids located at the C-terminal side of motilin were removed) was devoid of any contractile capacity, while synthetic fragments whose C-terminal structure extended beyond the 1-9 motilin sequence maintained almost complete biological activity. N-terminal amino acid sequence 1-9 is therefore an essential determinant of the contractile activity of motilin.

Animals↗
PubMed1992

The influence of dynamic factors on triaxial net muscular moments at the L5/S1 joint during asymmetrical lifting and lowering.

Asymmetrical lifting and lowering are predominant activities in the workplace. Mechanical causes are suggested for many back injuries and the dynamic conditions within which spine loading occurs are related to spine loading increase. More data on tridimensional biomechanical lumbar spine loading during asymmetrical lifting and lowering are needed. A tridimensional dynamic multisegment model was developed to compute spinal loading for asymmetrical box-handling situations. The tridimensional positions of the anatomical markers were generated by a direct linear transformation algorithm adapted for the processing of data from two real and two virtual views (mirrors). Two force platforms measured the external forces. Five male subjects performed three variations (slow, fast and accelerated) of asymmetric lifting and two variations (slow and fast) of asymmetric lowering. The torsional, extension/flexion and lateral bending net muscular moments at the L5/S1 joint were computed and peak values selected for statistical analysis. For the lifting task, the fast and accelerated conditions showed significant increases over the slow condition for torsion, extension/flexion and lateral-bending moments. The accelerated condition also showed significant increases over the fast condition for extension. A comparison between lifting and lowering tasks showed equivalent loadings for torsion and extension. The moments were compared to average maximal values measured on equivalent male subject populations by isokinetic dynamometry. This showed torsional and extension values of 30 and 83% of the maximal possible subject capacity, respectively. These results demonstrated that dynamic factors do influence the load on the spine and highlighted the influence of both lifting and lowering on the loading of the spine. This suggested that for a more complete analysis of asymmetrical handling, the maximal velocity and acceleration produced during lifting should be included.

Adult↗
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↗