Biomedical subjects

R Duchesne

Publications and source records attributed to R Duchesne.

13 recordsLinked to original sources

PubMed2001

UT-A urea transporter protein in heart: increased abundance during uremia, hypertension, and heart failure.

Urea transporters have been cloned from kidney medulla (UT-A) and erythrocytes (UT-B). We determined whether UT-A proteins could be detected in heart and whether their abundance was altered by uremia or hypertension or in human heart failure. In normal rat heart, bands were detected at 56, 51, and 39 kDa. In uremic rats, the abundance of the 56-kDa protein increased 1.9-fold compared with pair-fed, sham-operated rats, whereas the 51- and 39-kDa proteins were unchanged. We also detected UT-A2 mRNA in hearts from control and uremic rats. Because uremia is accompanied by hypertension, the effects of hypertension per se were studied in uninephrectomized deoxycorticosterone acetate salt-treated rats, where the abundance of the 56-kDa protein increased 2-fold versus controls, and in angiotensin II-infused rats, where the abundance of the 56 kDa protein increased 1.8-fold versus controls. The 51- and 39-kDa proteins were unchanged in both hypertensive models. In human left ventricle myocardium, UT-A proteins were detected at 97, 56, and 51 kDa. In failing left ventricle (taken at transplant, New York Heart Association class IV), the abundance of the 56-kDa protein increased 1.4-fold, and the 51-kDa protein increased 4.3-fold versus nonfailing left ventricle (donor hearts). We conclude that (1) multiple UT-A proteins are detected in rat and human heart; (2) the 56-kDa protein is upregulated in rat heart in uremia or models of hypertension; and (3) the rat results can be extended to human heart, where 56- and 51-kDa proteins are increased during heart failure.

Adult↗

PubMed1998

Intraocular pressure change measured by Goldmann tonometry after laser in situ keratomileusis.

PURPOSE: To assess the accuracy of Goldmann tonometry after laser in situ keratomileusis (LASIK). SETTING: University-based refractive surgery group (Clinique du Laser Visuel). METHOD: The database of patients who had LASIK was retrospectively reviewed. Preoperative and postoperative intraocular pressure (IOP) was measured in 145 patients. The correlation between decrease in IOP and various preoperative and intraoperative parameters was evaluated by regression analysis. Only one eye in patients having bilateral surgery was used for statistical analysis. RESULTS: Laser in situ keratomileusis was associated with a mean decrease in IOP of 1.9 mm Hg +/- 2.9 (SD). There was no significant correlation between the decrease and any parameter evaluated. CONCLUSION: Intraocular pressure after LASIK decreased by a mean of 1.9 +/- 2.9 mm Hg. The cause of the decrease remains unknown.

Adult↗

PubMed1997

[Polyethylene wear of the Optifix cementless acetabular component after 5 years].

The aim of this study is to review our experience with the Optifix porous-coated cementless acetabular component at an average 5 year follow-up. In a retrospective clinical investigation, the amount and rate of linear wear of the polyethylene of 26 cementless Optifix acetabular components implanted during a primary Hybrid (Spectron femoral component) total hip replacement in 24 patients, were determined by a comparison of the thicknesses of the cup as measured on the initial and most recent follow-up radiographs. The measurements were corrected for magnification error by direct measurement of the diameter of the femoral head on each radiograph according to the technique of Livermore et al. The mean duration of follow-up was 60 months (range, 48 to 73 months). Linear wear averaged 0.53 +/- 0.12 mm (0 to 2.28 mm) overall, with a mean rate of 0.11 +/- 0.02 mm (range 0 to 0.46 mm) per year p < 0.005. No osteolysis of the acetabulum was seen. None of the acetabular components migrated. Osteolysis of the endosteum of the femur was found in six hips. None of the femoral components subsided. In conclusion, wear of the polyethylene in this cup has not been previously reported, and is consistent with results published with other types of acetabular components.

Aged↗

PubMed1993

[Non-cemented self-locking total arthroplasty of the hip. Clinical and radiological results after three years].

We reviewed 47 patients who had fifty-one (51) primary, cementless biofit total hip arthroplasties (THA) implanted at Maisonneuve-Rosemont Hospital between 1986 and 1990. An independent observer rated the patients on the Harris Hip Score (HHS) by questionnaire, physical examination and radiological assessment. The average follow-up was 40 months. Twenty-two percent (22%) of the femoral components had been revised because of incapacitating pain, limping or a HHS inferior to 60. A little more than 20% of the unrevised prostheses had a mediocre result (HHS inferior to 70). There was no correlation between results and radiological signs of instability. The femoral component of the hip arthroplasty has a poor clinical performance which compares unfavourably with cemented prostheses.

Female↗

PubMed1990

[Analysis of non-optimal behavior in a dichotomous choice situation].

Proteau and Girouard (1987) have recently proposed a model to explain the decisional process that takes place in a two-choice reaction time situation. Although the model was well supported by the experimental data reported by these authors, a few unexplained results were observed and hypotheses were suggested to account for them. The goal of the present experiment was, first, to replicate the results presented by Proteau and Girouard (1987) to support their model. Our second goal was to determine if the unexpected results reported by these authors can be linked to some particular conditions occurring in the normal course of an experiment. The results obtained in the present experiment totally supported the proposed model. Furthermore, a detailed analysis of the circumstances under which unexpected results occurred did not permit the identification of any particular conditions favoring their occurrence. In conclusion, the proposed model, although reliable for about 95% of the trials, is still imperfect.

Choice Behavior↗

PubMed1990

Hip fractures and Parkinson's disease. A clinical review of 94 fractures treated surgically.

A series of 87 parkinsonian patients with 94 hip fractures were reviewed to reexamine the evidence for internal fixation versus hemiarthroplasty. Forty-seven subcapital Garden Type I and Type II fractures and transcervical fractures were treated by nailing, and 47 Garden Type III and Type IV fractures were treated by hemiarthroplasty. There were twice as many complications in the hemiarthroplasty group as in patients treated by nailing, including four wound infections and five dislocations, all with uniformly bad results. Patients treated by nailing regained greater ambulatory independence than those with a hemiarthroplasty. The parkinsonian patients with hip fractures treated by internal fixation had better results than those treated by hemiarthroplasty; hemiarthroplasty may be even contraindicated.

Aged↗

PubMed1989

Bone imaging after cementless press fit total hip arthroplasty.

In view of the high rate of loosening of conventional cemented hip prostheses, cementless implants are gaining popularity in Europe and North America. Smooth-surfaced "press fit" prostheses are designed for autolocking in the femoral canal at the time of installation. Fifteen patients were prospectively followed by bone imaging with Tc-99m MDP at three-month intervals after cementless "press fit" hip arthroplasty to define the "normal" distribution of mechanical stress to the surrounding bone, as well as the incorporation of bone allografts used for reconstruction of resorption sites in cases of revision surgery.

Adult↗

PubMed1988

Full oestrogenic activity of C19-delta 5 adrenal steroids in rat pituitary lactotrophs and somatotrophs.

Oestrogens are known to exert specific stimulatory effects on basal and dopamine (DA)-inhibited prolactin (PRL) release as well as on PRL cell content in rat adenohypophysial cells in primary culture. Recently, we have demonstrated that classical oestrogens increase growth hormone (GH) release and cellular GH content in rat pituitary somatotrophs. Since there is evidence that 5-androstene-3 beta, 17 beta-diol (delta 5-diol), a metabolite of dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEA-S) can induce typical oestrogenic responses in target tissues, we have investigated the effect of C19 adrenal steroids and compared them to that of 17 beta-oestradiol (E2) on the above-indicated parameters. Following a 72-h incubation, maximal concentrations of E2, delta 5-diol and DHEA caused a similar increase in PRL cell content at respective EC50 values of 0.020, 14 and 115 nM. The sensitivity of lactotrophs to DA action was decreased by approximately 4-fold after a 48-h exposure to maximal concentrations of delta 5-diol or DHEA. The time course of the antidopaminergic effect of delta 5-diol and DHEA was almost superimposable to that of E2. A 72-h incubation with 5 microM DHEA-S, a concentration within the range of blood levels found in women, doubled (P less than or equal to 0.001) cellular PRL accumulation. On the other hand, androstenedione (delta 4-dione) was without effect on any of the parameters measured. All stimulatory effects induced by maximal effective concentrations of delta 5-diol, DHEA or DHEA-S were competitively inhibited by simultaneous incubation with the antioestrogen LY156758. The amplitude of the stimulatory effects of delta 5-diol and DHEA on GH cell content as well as on spontaneous GH-releasing factor (GRF)-induced GH release was superimposable to that observed with E2. The effect of the steroids on GH cell content was exerted at 0.016 nM (E2), 12 nM (delta 5-diol) and 250 nM (DHEA). Simultaneous incubation with LY156758 completely blocked the effect of maximally effective concentrations of E2, delta 5-diol and DHEA in somatotrophs. Furthermore, a physiological concentration of DHEA-S (5 microM) enhanced spontaneous as well as GRF-induced GH release. On the other hand, delta 4-dione as well as testosterone and dihydrotestosterone did not alter GH release. The present data demonstrate that delta 5-diol, DHEA and DHEA-S can exert full oestrogenic effects in lactotrophs and somatotrophs, thus supporting their potential oestrogenic role under both physiological and pathological conditions.

Androgens↗

PubMed1985