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C Roux

Publications and source records attributed to C Roux.

At least 109 records · Page 6Linked to original sources
PubMed1998

Understanding coronary artery movement: a knowledge-based approach.

The aim of this paper is to describe a knowledge-based system that interprets three-dimensional (3D) coronary artery movement, using data from digital subtraction angiography image sequences. Dynamic information obtained from artery centerline 3D reconstruction and optical flow estimation, is classified according to experimental evidence indicating that artery displacements are quasi-homogeneous by a segment analysis. Characteristic motion features like displacement direction, perpendicular/radial components, rotation direction, curvature and torsion are qualitatively described from an image sequence using symbolic labels. These facts are then related and interpreted using anatomical-functional knowledge provided by a specialist, as well as spatial and temporal knowledge, applying spatio-temporal reasoning schemes. Facts, knowledge and reasoning rules are stated in a declarative form. Detailed examples of local and global interpretation results, using a real reconstructed angiographic biplane image sequence are presented in order to illustrate how our system suitably interprets coronary artery dynamic behavior.

Angiography, Digital Subtraction↗
PubMed1998

Identification of new early auxin markers in tobacco by mRNA differential display.

Differential display of mRNA has been improved by developing a two-step PCR amplification procedure. The modified differential display has been applied to identify early alterations of mRNA expression in response to auxin treatment of tobacco seedlings. This approach has led to the isolation of four fragments corresponding to auxin-up-regulated mRNAs. One, named GO15-13, shows significant homology with the 3' end of the coding region of the soybean SAUR X10A. The three other fragments present no homology with sequences available in the databases and constitute potential new early auxin markers.

Gene Expression Regulation, Plant↗
PubMed1998

Molecular cloning and expression of the early auxin-responsive Aux/IAA gene family in Nicotiana tabacum.

Early auxin-regulated tobacco cDNAs, belonging to the Aux/IAA gene family have been isolated by screening of a cDNA library prepared from auxin-treated suspension-grown etiolated seedlings of Nicotiana tabacum. The probes used were either RT-PCR fragments or an insert resulting from mRNA differential display selection. All of them possessed the structural features which characterize the Aux/IAA gene products. The auxin response of three distinct Nt-iaa subclasses has been characterized in terms of kinetics, dose-response and specificity as several plant hormones and chemicals have been tested for their ability to alter Nt-iaa mRNA accumulation. Differences of auxin responses have been observed between the Nt-iaa analysed, revealing significant differences of regulation. The effect of the protein synthesis inhibitor cycloheximide suggested that Nt-iaa2.3, Nt-iaa4.3 and strictly related genes can be classified as primary auxin-responsive genes and Nt-iaa28 as a late one. The steady-state mRNA level of these Nt-iaa has also been determined in organs of tobacco plants.

Amino Acid Sequence↗
PubMed1998

Clinical evaluation of spine morphometric X-ray absorptiometry.

A new method for vertebral height measurements, morphometric X-ray absorptiometry (MXA) based on dual-energy X-ray absorptiometry, has been proposed. This technique overcomes some limitations of morphometric radiography (MRX): the effective radiation dose is low, some sources of geometric distortion are eliminated, such as dependence on patient position, magnification gradient, and the effect of scoliosis is minimized. The purpose of this study was to compare morphometric parameters obtained by both methods (MXA and MRX), and to evaluate the agreement between morphometric evaluations and qualitative reading for vertebral fracture diagnosis. The evaluation was performed with an Hologic QDR 2000 device in 67 women without vertebral fractures and 31 women with vertebral fractures (according to a qualitative assessment). The reproducibility of the image analysis was <4% and comparable to MRX. The estimated bias between the two methods was on average 10 mm, and was a function of the vertebral height, according to the Bland and Altman method. The agreement between MXA and other methods for vertebral fracture diagnosis was poor for the thoracic level above T7, due to a lack of resolution and rib interposition. Agreement was also low for T10, due to the motion of the diaphragm muscle. MXA cannot currently be used for the diagnosis of thoracic vertebral fracture in clinical practice. Technological improvements are necessary to make this promising method useful as a screening tool to evaluate the presence of thoracic vertebral fractures.

Absorptiometry, Photon↗
PubMed1998

Treatment of skeletal involvement in neoplastic bone diseases.

Skeletal complications are frequent and increase morbidity dramatically in patients with malignancies. The role of bone resorption has been stressed leading to a key role for osteoclasts in the bone lesions. Specific and sensitive markers of bone resorption are now available. Bisphosphonates, powerful inhibitors of osteoclasts, can benefit patients with neoplastic bone diseases.

Bone Density↗
PubMed1998

Dynamic feature extraction of coronary artery motion using DSA image sequences.

This paper aims to define and describe features of the motion of coronary arteries in two and three dimensions, presented as geometrical parameters that identify motion patterns. The main left coronary artery centerlines, obtained from digital subtraction angiography (DSA) image sequences, are first reconstructed. Thereafter, global and local motion features are evaluated along the sequence. The global attributes are centerline and point trajectory lengths, displacement amplitude, and virtual reference point, while local attributes are displacement direction, perpendicular/radial components, rotation direction, and curvature and torsion. These kinetic features allow us to obtain a detailed quantitative description of the displacements of arteries' centerlines, as well as associated epicardium deformations. Our modeling of local attributes as quasi-homogeneous on a segment analysis, enables us to propose a novel numeric to symbolic image transformation, which provides the required facts for knowledge-based motion interpretation. Experimental results using real data are consistent with cardiac dynamic behavior.

Algorithms↗
PubMed1998

Randomized trial of effect of cyclical etidronate in the prevention of corticosteroid-induced bone loss. Ciblos Study Group.

Osteoporosis is a well-recognized adverse effect of corticosteroid therapy. This study aimed to investigate the effect of etidronate, intermittent cyclical therapy, in the prevention of corticosteroid-induced bone loss. Patients with various medical conditions starting high-dose corticosteroid therapy were enrolled in the study. The treatment had to be expected to continue for at least 12 months with the initial 90 days at a mean daily dose of at least 7.5 mg of prednisone, with subsequent treatment of at least 2.5 mg/day. One hundred seventeen patients were randomly assigned oral etidronate 400 mg/day, or placebo, for 14 days, followed by 76 days of oral calcium carbonate (500 mg elemental calcium), cycled over 12 months. The primary outcome measure was the difference in percent change from baseline in bone mineral density of the lumbar spine between the groups at the end of year 1. Secondary measures included changes in femur bone density and in biochemical markers of bone remodeling. The mean (+/- SEM) lumbar spine bone density changed 0.30 +/- 0.61% and -2.79 +/- 0.63% in the etidronate and placebo groups, respectively. The mean difference between groups after 1 yr was 3.0 +/- 0.84% (P = 0.004). The changes in the femoral neck and great trochanter were not different between the groups. There was a decrease in pyridinium crosslinks, significant from baseline at both 6 and 12 months, in the etidronate group. Osteocalcin increased in the placebo group, and difference between groups was -25.07 +/- 14.89% (P = 0.032) and -34.68 +/- 19.77% (P = 0.051), at 6 and 12 months respectively. There was no significant difference between the groups in number of adverse experiences, including gastrointestinal disorders. Etidronate intermittent cyclical therapy prevents lumbar vertebral bone loss in patients starting high-dose corticosteroid therapy.

Adrenal Cortex Hormones↗
PubMed1998

The diuretic indapamide increases bone mass and decreases bone resorption in spontaneously hypertensive rats supplemented with sodium.

Clinical and epidemiological studies suggest that thiazide diuretics can prevent bone loss and decrease the incidence of hip fractures. However, the mechanism of the effect of diuretics on bone is not clearly established. Indapamide (IDP), a sulfonamide diuretic related to thiazides, is used to treat hypertension. Sixty spontaneously hypertensive rats (SHRs) were divided into four groups and treated with or without IDP (1.5 mg/kg/day) during 8 weeks in the presence or absence of a high sodium load (8% NaCl supplementation in the diet). Sodium and calcium excretions were increased in the rats receiving the high sodium load (SHR + 8% NaCl) comparatively with control rats (SHR). IDP decreased and increased, respectively, calcium and sodium excretions. Serum parathyroid hormone (PTH) was unchanged in any group. Bone density was measured at the femur, tibia, and vertebrae, and bone morphometry was performed at the metaphysis of the femur to evaluate bone architecture. Rats fed a high sodium diet had an average 5.5% decreased bone density at every site except the femoral diaphysis. The trabecular bone volume was also decreased (SHR + 8% NaCl vs. SHR, 11.99+/-0.78 vs. 17.51+/-1.5%, p < 0.05). An increase in trabecular separation suggested that these changes were due to increased bone resorption. In the SHR + 8% NaCl + IDP group, IDP increased bone density and trabecular bone volume (SHR + 8% NaCl + IDP vs. SHR + 8% NaCl, 16.52+/-1.04 vs. 11.99+/-0.78%, p < 0.05). Trabecular separation and pyridinoline/creatinine excretion (SHR + 8% NaCl + IDP vs. SHR + 8% NaCl, 136.39+/-9.62 vs. 195.18+/-22.34 nmol/mmol, p < 0.05) were also decreased by IDP. These results show that in rats receiving a high sodium diet, IDP can reverse sodium-induced bone loss and increased bone resorption independently of changes in serum PTH.

Absorptiometry, Photon↗
PubMed1998

Broadband ultrasound attenuation at the calcaneus measured using a new contact ultrasound unit.

We evaluated a new contact ultrasound device, developed and manufactured in France, for measuring broadband ultrasound attenuation at the calcaneus. We first studied the influence on measurement results of a number of parameters including the nature of the coupling agent, heel position, transducer temperature, and foot vasodilation. We then determined the reproducibility of the measurements (2.14 +/- 1.07% in the medium-term) and established reference values in women (n = 612) and men (n = 106). Broadband ultrasound attenuation decreased between 25 and 85 years of age by 34% in women and 17% in men. Sensitivity and specificity for detection of decreased bone mass at the calcaneus were 85.5% and 81.5%, respectively. Sensitivity and specificity of the measurement at the calcaneus as compared to the lumbar spine were 90.7% and 89.1%, respectively. This unit intended for screening purposes is very easy to use, and the measurements it provides are immediately available. It can be expected to help determine the optimal strategy for use of ultrasound in the management of osteoporosis.

Adult↗
PubMed1998

[Inverted Y partial ureteral duplication. Apropos of an unusual case].

Inverted Y partial ureteric duplication corresponds to the presence of a variable length of duplicated ureter before entering the bladder in an orthotopic or ectopic position. A case od inverted Y partial ureteric duplication with ureteric confluence in the hilum of the kidney associated with anastomosis of an ectopic ureter in the epididymis is reported. The description of this original case is compared with the data of the literature.

Adult↗
PubMed1998

[Primitive psoas abscess in children; diagnostic difficulties and non surgical treatment: apropos of 2 cases].

From an analysis of two files of children carriers of primitive psoas abscess, the authors report the difficulties of diagnosis due to the rarity of this affection and the similarities of its symptomatology with ostearthritis of the hip which is a common pathology at the pediatric surgery unit of C.H.U. Yopougon (Republic of Côte d'Ivoire). A non surgical treatment made of antibiotherapy and traction fixed in the axis of the limb is proposed, since it helped the two patients who had presented an echographical stage II of psoas abcess to recover without after-effects.

Anti-Bacterial Agents↗
PubMed1997

Isolation by differential display and characterization of a tobacco auxin-responsive cDNA Nt-gh3, related to GH3.

By use of differential display, we have isolated a new early auxin-responsive cDNA in Nicotiana tabacum. Nt-gh3 had 70% identity with the unique GH3 sequence isolated in soybean by Hagen et al. [Planta 162 (1984) 147-153] and is thus the first reported cDNA related to this gene until now. Nt-gh3 mRNA accumulates within a short time after auxin treatment, responds to very low concentrations of NAA (as little as 10[-9] M) and specifically to active auxins. Nt-gh3 mRNA is demonstrated to be one of the most relevant early molecular markers of primary auxin response.

Amino Acid Sequence↗
PubMed1997

Cholesterol biosynthesis inhibited by BM15.766 induces holoprosencephaly in the rat.

To confirm that blocking 7-dehydrocholesterol delta 7 reductase (7DHC reductase), as observed in Smith-Lemli-Opitz syndrome (SLOS), induces craniofacial defects, we tested BM15.766, which blocks 7DHC reductase but is chemically unrelated to the holoprosencephaly-inducing teratogen AY9944. Rats were given BM15.766 either in methylcellulose from days (D) 1 through D11 (3 treated groups: protocol A) or in olive oil from D4 through D7 (300 mg/kg/d: protocol B). The sera were sampled on D0, D3, and D5 or D6, D10, D14, and D21 to measure cholesterol and dehydrocholesterols in all groups and steroid hormones in protocol B. D21 fetuses showed the holoprosencephaly spectrum of malformations and the treated dams low cholesterol and accumulation of 7DHC, 8DHC, and trienols, as in SLOS-affected children. In the 3 dosage groups the malformations were dose-related and enzymatic cholesterol decreased to a plateau. The DHC reached 25-44% of the total sterols in the dams. In protocol B, one-third of the BM15.766-treated fetuses presented facial malformations and almost two-thirds pituitary agenesis. On D10, cholesterol reached a minimum and the DHC a maximum while estradiol 17 beta and progesterone were lowered, the latter decreasing in correlation with cholesterolemia. A sterol profile similar to that previously observed after AY9944 associated with a similarly high incidence of pituitary agenesis confirmed that time-limited inhibition of 7DHC reductase induces holoprosencephaly and that pituitary agenesis is the minor form of holoprosencephaly.

Animals↗
PubMed1997

Effects of cyclical etidronate therapy on bone loss in early postmenopausal women who are not undergoing hormonal replacement therapy.

This study was carried out to investigate the effectiveness and tolerability of cyclical etidronate therapy in the prevention of bone loss occurring in early postmenopausal women who are not undergoing hormone replacement therapy (HRT). A total of 109 Caucasian women aged 45-60 years were treated with etidronate 400 mg/day or placebo for 14 days followed by calcium supplementation 500 mg/day for 77 days. Ninety-one women completed the 2 years of the study. After 2 years, the estimated difference between the two groups as regards lumbar spine bone mineral density (BMD) was 2.53% (SEM 1.07%; p = 0.01); BMD of the hip and wrist were not significantly different between treatment groups. A clear reduction in bone turnover was obtained as evidenced by a significant decrease in serum alkaline phosphatase level and in urinary N-telopeptide/ creatinine ratio in the etidronate group; the difference between the two groups was -12% +/- 3.2% for serum alkaline phosphatase level (p = 0.019) and -22.9% +/- 13.7% for the urinary N-telopeptide/creatinine ratio (p = 0.047). There was no statistically significant difference between the two groups in terms of the serum osteocalcin levels and urinary hydroxyproline/ creatinine and calcium/creatinine ratios. Etidronate was generally well tolerated and its adverse event profile was similar to that of placebo. The results of this study indicate that cyclic etidronate therapy can prevent trabecular bone loss, with no deleterious effect on cortical bone, in the first 5 years of menopause and that it has a very high safety margin.

Alkaline Phosphatase↗
PubMed1997

Assessment of the relationship between broadband ultrasound attenuation and bone mineral density at the calcaneus using BUA imaging and DXA.

The purposes of this study was to determine the relationship between broadband ultrasound attenuation (BUA) and bone mineral density (BMD) measured at different regions of the calcaneus with identical site-matched regions of interest (ROIs). Dual-energy X-ray absorptiometry (DXA) measurements of the calcaneus and BUA imaging were performed in 30 women (15 premenopausal and 15 postmenopausal). Four square ROIs were located in the great tuberosity and one square ROI in the foramen calcaneus. A ROI adapted to the shape and size of the whole calcaneus was also considered. All ROIs were analyzed three times with both techniques to minimize intra-observer variability. The correlation coefficient between attenuation and frequency was used as an index of BUA measurement error. Before accepting a measurement of BUA in inhomogeneous material, it could be useful to map the spatial variations of the measurement error. In all ROIs we found the BUA and BMD were strongly related (r = 0.78-0.91, p < 0.001). The correlation between BUA and BMD was slightly higher in the inferior part of the posterior tuberosity than in the superior part and in the foramen calcaneus. The very high correlation between attenuation and frequency found in all ROIs (r = 0.99) suggests that measurement errors of propagation were probably not significant. Ultrasound imaging yields the opportunity for studying the spatial acoustic properties in the calcaneus and their relation to bone mass or structural parameters provided by independent imaging techniques. BUA measured with current transmission techniques reflects mainly bone mass, and microarchitecture to a smaller extent.

Absorptiometry, Photon↗