Search PubMed⌕ Search

Biomedical subjects

L Tétreault

Publications and source records attributed to L Tétreault.

At least 19 recordsLinked to original sources
PubMed1986

Oscillometry and direct blood pressure: a comparative clinical study during deliberate hypotension.

Oscillometry using an automatic monitor was compared with invasive blood pressure monitoring in 21 patients scheduled for surgery under general anaesthesia with deliberate hypotension. Six ranges of mean blood pressure measurements were studied, two of which were hypotensive. An excellent correlation was found between the two methods (systolic: r = 0.94; mean: r = 0.93; diastolic: r = 0.88) but there was a large variability among individual subjects. For systolic, diastolic and mean intra-arterial readings above an approximative value of 10.64 KPa (80 mmHg), the oscillometric monitor was found to underestimate blood pressure. Inversely, it was found to overestimate blood pressure for intra-arterial readings under the approximative value of 10.8 KPa (80 mmHg). We conclude that the non-invasive monitor represents a good trend estimation of the invasive radial blood pressure technique, but that wide inter-individual variability and the overestimation of blood pressure below an approximative value of 10.64 KPa (80 mmHg) precludes interchange of techniques when absolute values are considered, especially during controlled hypotension. However, oscillometry could represent a better estimate of central aortic pressure.

Adult↗
PubMed1985

Comparative esophageal and anorectal motility in scleroderma.

Esophageal and anorectal pressures were recorded in 26 patients (4 men and 22 women) with scleroderma. Eleven patients suffered from a localized form of the disease and 15 from progressive systemic sclerosis. The latter only had marked functional abnormalities in esophageal and anorectal motility. Mean resting pressure at the lower esophageal sphincter of patients with progressive system sclerosis and controls was, respectively, 6 +/- 2 and 25 +/- 1 mmHg (p less than 0.001); mean closing pressure was 5 +/- 5 and 48 +/- 3 mmHg (p less than 0.001); coordination of opening the lower esophageal sphincter with the oncoming contraction in the distal esophagus was 0% and 68% +/- 5% (p less than 0.001); and relaxation (fall of the lower esophageal sphincter pressure to resting levels in the stomach) was 18% +/- 12% and 98% +/- 1% (p less than 0.001). The rectoanal inhibitory reflex was of lesser amplitude than normal in 74% of patients with progressive system sclerosis and was absent in 13%. Quantitative analysis demonstrated a significant reduction in response to rectal distention with 20 or more ml of air (p less than 0.001). There was a correlation between the amplitude of the lower esophageal sphincter relaxation and the amplitude of the rectoanal inhibitory reflex in response to rectal distention with 30-50 ml of air (p less than 0.05 to p less than 0.025). Our data show that in systemic sclerosis, anorectal motility is as frequently abnormal as esophageal motility.

Adult↗
PubMed1984

Adjuvant arthritis: influence of the adjuvant volume and composition on the established arthritis.

Adjuvant arthritis remains an interesting model for the evaluation of therapeutic agents and for the study of inflammatory mechanisms. The severity and time course of the primary nonspecific inflammation and of the induced polyarthritis are influenced by the composition and volume of the injected adjuvant. The injection of complete adjuvant produces always an oedema which is much greater than the sum of the oedemas induced by mineral oil or mycobacteria alone. In Lewis rats, highly susceptible to adjuvant arthritis, the intensity of the induced lesions increases with the injected oil volume and for equal volumes is maximal with 500 micrograms of Mycobacterium butyricum. In the injected paw the specific immune character of the inflammation is more important when a small volume of adjuvant is used and is maximal for 500 micrograms of mycobacteria in 0.1 ml of mineral oil.

Animals↗
PubMed1983

Comparative study of gastrointestinal microbleeding caused by aspirin, fenbufen, and placebo.

Fifty volunteers, randomly divided into five groups, received placebo, fenbufen, or aspirin at dosages used in treating osteoarthritis and rheumatoid arthritis (fenbufen, 600 or 900 mg daily; aspirin, 3.6 g daily) for 28 days. Following radioactive chromium labeling of red cells in each subject, stool specimens were collected weekly for determination of blood loss by radioisotope procedure. Statistical analyses demonstrated no significant differences in gastrointestinal microbleeding between subjects who received fenbufen (600 or 900 mg daily) and those who received placebo. Conversely, there were significant (p less than 0.01) differences in microbleeding between subjects given aspirin and those given either dosage of fenbufen or placebo.

Adolescent↗
PubMed1983

Constipation with colonic inertia. A manifestation of systemic disease?

Transit of radiopaque markers was delayed in the ascending colon of 51 females and 3 males treated for severe idiopathic constipation. Onset of symptoms was between age 10 and 20 in more than half of the patients. Eighteen percent had previously undergone unnecessary laparotomy for large bowel pseudoobstruction. Stool frequency ranged from 1 stool every three days to 1 every 2 months. Twenty-six percent suffered from fecal incontinence. In addition, 30% had orthostatic hypotension and 15% galactorrhea of idiopathic origin. Patients had a higher than normal anal pressure (P less than 0.001). They all had a rectoanal inhibitory reflex, but it was abnormal in 76%. In the upper esophageal sphincter, resting pressure was higher (P less than 0.02), and coordination poorer (P less than 0.05) than in normal control subjects. Incidence of spontaneous tertiary contractions in the body of the esophagus was greater than normal (P less than 0.03). In the lower esophageal sphincter, resting pressure was lower (P = 0.001) and gastroesophageal gradient weaker (P = 0.05). Closing pressure of the sphincter was lower (P less than 0.001) and coordination less adequate (P less than 0.02). After subcutaneous injection of 0.035 mg/kg bethanechol, urinary bladder intraluminal pressure increased by over 15 cm H2O in 31% of patients but never did in controls, and average maximal pressure was greater (P less than 0.025). Time taken to reach peak pressure was shorter (P less than 0.01). This study provides evidence that patients who suffer from constipation with colonic inertia also have abnormal function in other hollow viscera.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Nuclear androgen receptors of human prostatic tissue--a quantitative histological study.

The objective of this study was to determine the nuclear dihydrotestosterone (DHT) nuclear receptors content in tissues of normal prostate, benign prostatic hypertrophy (BPH), and prostatic cancer. We also attempted to correlate this with the histological pattern of these tissues. Specimens were obtained from five normal subjects, 24 BPH, and 19 prostatic cancer patients. Nuclear receptors content was determined. All histological sections were reviewed by three independent pathologists. The criteria for the quantitative analysis were the degree of cellularity and the stromal content. The mean receptor content was not significantly different between neoplastic tissue (52.6 fmol/mg protein) and hyperplastic tissue (38.9 fmol/mg protein). The number of binding sites in normal prostatic tissue was 8.5 fmol/mg protein. The correlation between the degree of cellularity and DHT receptors showed no significant difference for both BPH, as well as prostatic cancer. Similar results were obtained when stromal content was compared.

Adenocarcinoma↗
PubMed1983

Phagocytosis of sodium urate and calcium pyrophosphate crystals by leukocytes of gouty, pseudogouty and health donors.

The initial rates of oxygen consumption and of glucose oxidation via the hexose monophosphate shunt were measured during the phagocytosis of sodium urate and calcium pyrophosphate microcrystals. By applying the kinetics of an enzyme-catalyzed reaction, the affinity of the polymorphonuclear leukocytes for crystals, Km, and the maximum rate, Vmax, were determined. When the comparisons are made between the two kinds of crystals, the differences in Vmax are always significant (p less than 0.02). The lesser phlogistic properties of pyrophosphate crystals stem probably in part from different crystal-protein interactions. The influence of the donor is less marked. Part of the weakly depressed phagocytic activity observed with pseudogouty PMN may be attributed to antiinflammatory drugs.

Adult↗
PubMed1983

Iatrogenic lesions of the upper airway in the newborn.

A retrospective study of 140 babies who survived the first week of life and who had endotracheal intubation showed that 65 of them had either or both of the following complications of endotracheal tube therapy: (a) Collapse of one or more lobes with the tube in place or within the first two days following extubation and lasting less than 24 hours. When collapse lasted more than 48 hours, it often required repeated intubation for tracheal cleansing. The right lung, especially its upper lobe, was predominantly affected. (b) Tracheal lesions and nasal necrosis. A statistical comparison with intubated babies of similar age without complications showed the following factors to predispose to lobar collapse: younger gestational age, maximal high oxygen concentration administered, and prolonged duration of intubation. The results of endotracheal tube cultures bore no relation to the complication rate.

Airway Obstruction↗
PubMed1982

Cimetidine and plasma levels of gonadotropins, prolactin and gonadal steroids in women.

The endocrine effects of cimetidine (Tagamet) during the menstrual cycle were investigated in seven healthy female volunteers. The subjects were studied for six menstrual cycles divided into the pretreatment phase, a phase of therapy with 1.2 g of orally administered cimetidine daily for two cycles, and a post-treatment phase. Cimetidine therapy induced a significant increase in the mean plasma level of follicle-stimulating hormone during the periovulatory period, followed by modest but sustained hyperprolactinemia throughout the luteal phase of each cycle. No significant changes were found in the mean plasma levels of luteinizing hormone and progesterone, and the mean plasma estradiol level was significantly decreased only in the midproliferative phase of each cycle. The mean plasma prolactin levels after a bolus injection of thyrotropin-releasing hormone in the midluteal phase during cimetidine administration did not differ from the mean control levels, which indicates that cimetidine modulates the release of prolactin at the suprapituitary locus. However, the significance of the endocrine changes remains to be established.

Administration, Oral↗
PubMed1982

Gastrointestinal blood loss of oxaprozin and aspirin with placebo control.

The objective of this study was to compare the effects of oxaprozin (4,5-diphenyl-2-oxazolepropionic acid), a nonsteroidal, antiinflammatory compound, and aspirin in a double-blind, placebo-controlled study to estimate gastrointestinal bleeding. The determination of fecal blood loss was made quantitatively by the use of the radioactive (51Cr) technique. During the first week, subjects were controlled with and without placebo. At the end of the second week, the subjects were divided and randomly assigned to one of three groups; 10 received 1200 mg oxaprozin (600 mg twice daily), 11 received 3900 mg aspirin (975 mg four times a day), and the remaining 8 subjects received placebo for two weeks. During the last two weeks, all received placebo again. A statistical analysis of variance showed that there were no statistical differences between the groups during the first and last two weeks of placebo therapy. During the active treatment period, weeks 3 and 4, there were statistically significant differences among the three groups. The mean blood loss during week 3 was significantly greater for the aspirin group, 8.8 ml/day, than the oxaprozin group, 3.3 ml/day (P less than 0.05), and the placebo group, 1.4 ml/day (P less than 0.001). The smaller difference between oxaprozin and placebo was also significant (P less than 0.05). During the fourth week, the mean daily blood loss among oxaprozin patients had decreased to 2.3 ml/day, and no statistically significant difference from placebo (1.1 ml/day) was found.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1982

Epidural morphine for postoperative pain relief: a dose-response curve.

Different doses of epidural morphine were studied in order to determine their effectiveness in providing postoperative pain relief after surgery of the lower extremities and their relationship to the incidence of untoward reactions. The study was carried out in a double-blind fashion using five dosages of epidural morphine (0.5, 1.0, 2.0, 4.0, and 8.0 mg) and included 60 patients. The higher doses of morphine (2.0, 4.0, and 8.0 mg) were equally effective and more effective than the lower doses (0.5 and 1.0 mg) in providing postoperative analgesia. Nausea and vomiting were encountered more frequently with the highest dose (8.0 mg) and this finding was statistically significant (P less than 0.03). No statistically significant difference was found between the doses studied with regard to itching, urinary retention, and respiratory depression; the latter was evaluated in a subgroup of 20 patients. These data suggest that effective postoperative pain relief after surgery of the lower extremities can be achieved with relatively low doses of morphine sulfate and with minimal side effects. For the type of surgery studied, 2 mg morphine sulfate appeared to be the optimum dose.

Carbon Dioxide↗
PubMed1982

The gastric antisecretory effects of clofibrate in the rat.

The object of this study was to explore the effect of clofibrate on gastric secretion. The volume and the total acid output of Shay-treated rats (pyloric ligation) was studied after intragastric, intraduodenal, intramuscular and intraperitoneal administration of clofibrate. The experimental model was a factorial (3 X 4) random block design. The treatment factor had 3 levels: water, oil and clofibrate. The route of administration factor had 4 levels: intragastric, intraduodenal, intraperitoneal and intramuscular. The data were analyzed by analysis of variance. Compared to the control group (water and oil) the intraduodenally and intraperitoneally administered clofibrate produced a statistically significant (p less than 0.001) reduction in the volume and total acid output. The intragastric and intramuscular groups did not show a statistically significant reduction on the gastric secretion. It is concluded that clofibrate acts systemically rather than locally to reduce gastric secretion.

Administration, Oral↗
PubMed1981

Comparison of the clinical effectiveness of lidocaine hydrocarbonate and lidocaine hydrochloride with and without epinephrine in epidural anaesthesia.

Epidural analgesia was administered to one hundred patients undergoing various types of surgical procedures. They were divided at random into four equal groups who received lidocaine hydrocarbonate or lidocaine hydrochloride, both with or without epinephrine. A double blind method was used. The study was designed first to test the validity of claims that lidocaine hydrocarbonate produces a shorter period of onset for effective analgesia, a more profound sensory and motor block, and a higher spread of analgesia than the hydrochloride salt and secondly, to identify the respective roles of carbon dioxide and epinephrine in obtaining this alleged superior effectiveness. The results of the study showed that carbon dioxide improved the quality of sensory block, but we could not find any significant difference between lidocaine hydrocarbonate and lidocaine hydrochloride salt, with and without epinephrine, with regard to rapidity of onset, upward spread of analgesia and quality of motor block. As was already known, duration of analgesia was prolonged by the addition of epinephrine but not by the addition of carbon dioxide. They study also showed that the compliance of the epidural space was decreased in the lidocaine hydrocarbonate groups compared to those with lidocaine hydrochloride. There is a positive correlation between the duration of sensory block or the upper level of analgesia and compliance in the hundred patients studied. It is concluded that the hydrocarbonate base, because of its more profound sensory block in the L5-S1 segment, can be useful for operations on the lower extremities, especially in the L5-S1 segmental distribution. However, knowing that the hydrocarbonate base is more expensive, one must use his own judgment in appraising the cost-benefit of its use.

Adult↗
PubMed1981

Effects of carbon dioxide and epinephrine on serum levels of lidocaine after epidural anaesthesia.

Carbonated lidocaine is believed to penetrate membranes more rapidly than its hydrochloride salt and could possibly cause higher serum levels. To compare serum levels, arterial blood samples drawn at intervals were analyzed in a group of 18 patients under epidural anaesthesia with equivalent doses of lidocaine hydrochloride and lidocaine hydrocarbonate, with and without epinephrine. Results show that serum levels were significantly higher when lidocaine hydrocarbonate was used for epidural analgesia.

Anesthesia, Epidural↗
PubMed1981

Urorectodynamics in patients with colonic inertia.

Sixteen female patients with colonic inertia and 12 control women underwent manometric evaluation of their bladder and rectal cavities. After subcutaneous injection of 0.035 mg./Kg. bethanechol, bladder intraluminal pressure increased by over 15 cm. water in 5 patients (31 per cent) and in none of the control group; maximal pressure after injection was 11.5 +/- 1.6 cm. H2O (mean +/- SE) in patients and 8.5 +/- 1 in controls (p less than 0.025). The intraluminal rectal pressure reached 23 +/- 4 cm. H2O in patients and only 11.9 +/- 1.4 in controls (p less than 0.0025). Time taken to reach a peak pressure was faster in patients both in bladder (17.4 +/- 0.7 vs. 19.8 +/- 1.2 minutes; p less than 0.01) and in the rectum 914.6 +/- 0.8 vs. 16.3 +/- 1.2; p less than 0.025). These findings and the clinical presentation suggest an autonomic neuropathic lesion in this group of patients.

Adult↗
PubMed1981

Adjuvant arthritis: influence of the adjuvant volume and composition on the non-specific inflammation.

Adjuvant-induced arthritis is an animal model of chronic inflammatory disease widely used in anti-inflammatory and immunosuppressive drugs testing. When the development and the inhibition of the induced arthritis are measured by the injected paw oedema, it is difficult to delineate the immunological contribution from the persistent non-specific primary section. To study the influence of volume and composition of the injected adjuvant upon the primary non-specific inflammation, we devised a 3X4 factorial experiment on a strain of inbred rats with a low susceptibility to adjuvant-induced arthritis. The injection of mineral oil alone produces a persistent oedema. The injection of mycobacteriae in suspension in saline induces a rapid inflammatory response followed by a fast decrease of the oedema. When complete adjuvant is used, there is always a very strong interaction between the effects of the two components of the adjuvant, i.e. the measured oedemas are much greater than the calculated values, For a given injected volume, the inflammation is maximum when the concentration of mycobacteriae is 2.5 mg/ml. All the rats injected with complete adjuvant present a transient oedema of the non-injected hind paw. This oedema is very small and proportional to the amount of mycobacteria injected.

Adjuvants, Immunologic↗