PubMed Health⌕ Search

Biomedical subjects

D Guez

Publications and source records attributed to D Guez.

84 records · Page 5Linked to original sources
PubMed1983

[Conduction disorders and aneurysms of the sinus of Valsalva].

A series of 15 sinus of Valsalva aneurysms (SVA) admitted between 1961 and 1981 was reviewed to analyse associated conduction defects. It comprised 11 men and 4 women; the mean age was 31 years (range 16 to 53). The diagnosis of SVA was made at the time of rupture (4 cases), during investigation of associated cardiac disease (8 cases), at surgery (1 case) and during advanced conduction disorders (2 cases). All patients underwent catheterisation and angiography. Endocavitary electrophysiological studies were performed in 3 patients. Eight out of 15 patients had conduction defects which comprised: incomplete right bundle branch block (2 cases), atrioventricular block (AVB) (6 cases). Endocavitary investigation of 3 of the 6 AVB showed conduction defects at several levels: sino atrial, suprahisien, intrahisian and infrahisian blocks (1 case); transient complete AVB with 1 degree and 2 degree intrahisian block (1 case); complete AVB, six years after correction of SVA, due to infrahisian block (1 case). Thirteen of the 15 patients underwent surgery; none of the 9 cases of SVA without conduction defects before surgery developed conduction defects. Four of the 6 cases of AVB required permanent pacing; there was 1 postoperative death. One patient was not operated. These conduction defects were caused by the close relationship of the SVA to the intracardiac conduction pathways. The right anterior was the most commonly affected sinus. The investigation of AV conduction should be systematic in cases of SVA, and, conversely, the finding of AVB in young patients should alert the physician to the possibility of a SVA.

Adolescent↗
PubMedDate not supplied

Further evidence for a dissociation between different forms of mnemonic expressions in a mouse model of age-related cognitive decline: effects of tacrine and S 17092, a novel prolyl endopeptidase inhibitor.

It has been demonstrated previously on the radial maze that the emergence of an age-related mnemonic impairment is critically dependent on the form which the discrimination problems took. Hence, when the arms were presented one by one (i.e., successive go-no-go discrimination), both adult and aged mice learned to distinguish between positive (baited) and negative (unbaited) arms readily, as evidenced by their increased readiness to enter positive relative to negative arms (i.e., by a differential in arm-entry latencies). A selective impairment in the aged mice was seen when these arms were presented subsequently as pairs, such that the mice were confronted with an explicit choice (i.e., simultaneous 2-choice discrimination). When discriminative performance was measured by the differential run speed between positive and negative arms, aged mice were also impaired. This was particularly pronounced in the 2-choice discrimination condition. We examined the effects of tacrine (3mg/kg, subcutaneously) or S 17092 (10mg/kg, orally) in aged mice on the three behavioral indices of this 2-stage spatial discrimination paradigm. The results indicated that: (1) Tacrine, but not S 17092, enhanced the acquisition of go-no-go discrimination as reflected in arm-entry latencies; (2) both drugs improved choice accuracy in simultaneous discrimination, although the effect of tacrine was less striking and, in particular, far from statistical significance in the very first 2-choice responses; and (3) neither drugs significantly affected run-speed performance. We conclude further that the specific patterns of drug effects on the three indices of discriminative performance might suggest that each index is associated with a distinct form of mnemonic expression relying on separate neural systems.

Aging↗
PubMedDate not supplied

Pharmacokinetics of sustained and immediate release formulations of indapamide after single and repeated oral administration in healthy volunteers.

The pharmacokinetics of a 2.5 mg immediate release (IR) formulation of indapamide was compared to a 1.5 mg sustained release (SR) formulation of indapamide after single and repeated oral administration dose using double blind randomised cross-over studies. In the first study, 12 subjects received a single dose of each treatment: IR fasted, SR fasted or with food. In the second study one tablet of either formulation was administered daily for one week at breakfast. In each study, blood samples were collected pre dose (Cmin) and up to 120 h after the last dose. Urine was collected over the dosing interval (24 h). Following a single oral administration the SR formulation had a lower dose-normalised Cmax compared to the IR formulation (17.6 +/- 6.3 vs. 39.3 +/- 11.0 ng x mL(-1), respectively), a much longer t(max) (12.3 +/- 0.4 vs. 0.8 +/- 0.3 h) and a greater t75 (15.3 +/- 6.1 vs. 1.8 +/- 1.4 h) but there were no differences in dose-normalised AUC (559 +/- 125 and 564 +/- 146 ng x h x mL(-1)) nor in t(1/2z) values (14.8 +/- 2.8 vs. 18.4 +/- 13.4 h). The SR formulation clearly demonstrated sustained release characteristics as compared to the IR formulation. Food co-administration had no effect on dose-normalised AUC for the SR formulation. After repeated administration, steady-state was achieved by day 5. The absorption rate of the SR formulation was lower and the 24 h peak-to-trough fluctuation was 4-fold lower compared to the IR formulation. After dose correction there wasno change in AUC, (726 +/- 207 and 690 +/- 183 ng x mL(-1) x h for SR and IR, respectively). The elimination parameters (t(1,2z), Ae(tau), and CLr) remained unchanged. The SR formulation showed sustained release of indapamide with a reduction in peak concentration, while steady-state level was not affected by formulations. The two formulations have the same bioavailability.

Administration, Oral↗