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Biomedical subjects

C Roux

Publications and source records attributed to C Roux.

At least 109 records · Page 6Linked to original sources
PubMed2000

Evaluation of 1,2-indanedione and 5,6-dimethoxy-1,2-indanedione for the detection of latent fingerprints on porous surfaces.

The ability of 1,2-indanedione and 5,6-dimethoxy-1,2-indanedione to detect latent prints on porous surfaces, as compared to DFO and ninhydrin, has been evaluated. Comparisons of prints developed under various conditions determined the optimum development conditions for the new reagents. The indanediones tested were found to have lower detection limits for glycine. The carrier solvent used was found to affect the quality of the prints developed. In Arklone, the new reagents developed prints that displayed superior luminescence to those developed with DFO. In HFE 7100, 1,2-indanedione and 5,6-dimethoxy-1,2-indanedione gave superior luminescence to DFO after zinc salt treatment and cooling with liquid nitrogen, both of which improve the luminescence of prints developed with 1,2-indanediones. 1,2-Indanediones could offer less expensive but effective alternatives to DFO. With further optimization, the new reagents may supersede DFO as the method of choice for the detection of latent fingerprints on porous surfaces.

Dermatoglyphics↗
PubMed2000

A pooled data analysis on the use of intermittent cyclical etidronate therapy for the prevention and treatment of corticosteroid induced bone loss.

OBJECTIVE: To conduct a pooled data analysis in a group of patients defined by sex, menopausal status, and underlying disease in order to examine the effect of intermittent cyclical etidronate in the prevention and treatment of corticosteroid induced osteoporosis. METHODS: We selected 5 randomized, placebo controlled studies that examined the efficacy of intermittent cyclical etidronate therapy in which the raw data were available for analysis. Three were prevention studies and 2 treatment studies. The primary outcome was the difference between treatment groups in the percentage change from baseline in lumbar spine bone density. Secondary outcomes included the difference between treatment groups in the percentage change from baseline in femoral neck and trochanter bone density, and vertebral fracture rates. RESULTS: Results are separately pooled for the prevention and treatment studies. The prevention studies had significant mean differences (95% CI) between groups in mean percentage change from baseline in lumbar spine, femoral neck, and trochanter bone density of 3.7 (2.6 to 4.7), 1.7 (0.4 to 2.9), and 2.8% (1.3 to 4.2) after one year of treatment, in favor of the etidronate group. The treatment studies displayed a mean difference between groups in mean percentage change from baseline in lumbar spine bone density of 4.8 (2.7 to 6.9) and 5.4% (2.5 to 8.4) after one and 2 years of therapy. In the prevention studies, a reduced fracture incidence was observed in the etidronate group compared with the placebo group (relative risk 0.50; CI 0.21 to 1.19). CONCLUSION: Etidronate therapy was effective in preventing bone loss in the prevention studies and in preventing or slightly increasing bone mass in the treatment studies. A fracture benefit was observed in postmenopausal women treated with etidronate in the prevention studies.

Adult↗
PubMed2000

[Essential parathyroid cysts: a misleading lesion].

Though a rare lesion, non-functioning parathyroid cyst is of clinical significance because it usually mimics a thyroid nodule. The cyst can be ectopic in location and therefore constitutes a differential diagnosis to a bronchial or thymic cyst. Two recent cases of non-functioning parathyroid assay are reported. Needle puncture with estimation of the level of parathyroid hormone in the aspirate allows the diagnosis to be made before surgery.

Adult↗
PubMed1999

Absence of ventral cell populations in the developing brain in a rat model of the Smith-Lemli-Opitz syndrome.

The Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive condition involving craniofacial and central nervous system malformations with occasional holoprosencephaly (HPE). It is caused by a defect in the 7-dehydrocholesterol (7-DHC) reductase, the enzyme catalyzing the last step of cholesterol biosynthesis. Treatment of pregnant rats with inhibitors of 7-DHC reductase, either AY9944 or BM15.766, has provided a valuable model to study the pathogenesis in SLOS. Recently, cholesterol has been shown to be involved in the post-translational activation of the signaling protein Sonic Hedgehog. To identify the early defects associated with HPE in a rat model of SLOS, and to compare the phenotype of the treated embryos with that of the Shh(-/-) mutants, we examined brain morphology and expression of three developmental genes (Shh, Otx2, and Pax6 ) in 23-somite stage embryos from AY9944-treated dams. We report clearly abnormal morphology of the developing brain, concerning primarily the ventral aspect of the neural tube. We observed a reduced or absent expression of Shh and Otx2 in their ventral domain associated with extended ventral expression of Pax6. The results suggest an absence of the midline ventral cell type at all levels of the cranial neural tube. They provide further evidence that cholesterol-deficiency-induced HPE originates from impaired Shh signaling activity in the ventral neural tube.

Animals↗
PubMed1999

Phylogenetic relationships between European and Chinese truffles based on parsimony and distance analysis of ITS sequences.

Phylogenetic relationships among truffle species from Europe and China were investigated through parsimony analysis of the ITS sequences. Three major clades were obtained among the species analysed. The so-called white truffles appeared polyphyletic since Tuber magnatum was grouped with brown truffles and not with the other white species (T. maculatum, T. borchii, T. dryophilum, T. puberulum). The black truffles investigated in this study, T. brumale, T. melanosporum, T. indicum and T. himalayense, were grouped in an independent clade. The Périgord black truffle T. melanosporum and the Chinese black truffles T. indicum and T. himalayense, were very closely related. The delimitation of these species was estimated by a distance analysis on several isolates collected from different geographic areas. In spite of intraspecific variations of the internal transcribed spacers (ITS) sequences, T. melanosporum and the Chinese black truffles can be unambiguously attributed to distinct taxa.

Ascomycota↗
PubMed1999

Determination of age at death: assessment of an algorithm of age prediction using numerical three-dimensional CT data from pubic bones.

The determination of age at death is an important part of physical and forensic anthropology. Because of resistance to decomposition and the simplicity/accuracy ratio, the direct observation of the os pubis by Suchey-Brooks phase analysis is the preferred reference system for determination of age at death. We propose an age-prediction system using a pubic symphysis numerical database obtained from CT x-ray through quantification of age-linked parameters. Our system increases the accuracy of age estimation and at the same time preserves the integrity of the archeological material.

Adult↗
PubMed1999

Ultrasound measurement on the calcaneus: influence of immersion time and rotation of the foot.

The aim of this study was to evaluate the influence of immersion time and rotation of the heel around the leg axis on the reproducibility of measurements using an ultrasound bone imaging scanner (UBIS) with a temperature-controlled water bath. Measurements were obtained in 10 men, 11 premenopausal women and 10 postmenopausal women. The right foot of all subjects was scanned 12 times with an interval of 3 min between each scan. The first 10 measurements, performed to study the effect of immersion time, were taken without intermediate repositioning. Measurements 11 and 12 were also taken without removing the foot, but the calcaneus position was varied by an angle of +/-2.5 degrees with respect to the reference position used during the first 10 measurements. Prolonged immersion of the heel led to a decrease in the variations of quantitative ultrasound (QUS) parameters between successive measurements. Following rapid variations with immersion time, the QUS parameters reached a plateau. The effect of immersion time on measurement error remained significant until the first two or three scans for broadband ultrasound attenuation (BUA) and until the sixth or seventh scans for speed of sound (SOS). The variation in BUA was more pronounced (p<0.05) for the group of postmenopausal women (20. 7% change in BUA between the first and tenth scans; p<0.005) than for the group of premenopausal women (6.8% change in BUA between the first and tenth scans; p<0.005). The variations in SOS were similar in the two groups (0.8% variation; p<0.005). The impact of immersion time was smaller for men than for women [2.5%, (p<0.01) and 0.4% (p<0.005) of the change between the first and tenth scans for BUA and SOS respectively]. On the whole, the measurement errors due to rotation of the heel were lower than those caused by immersion time. The variations were significant only in men and premenopausal women. Both immersion time and rotation of the heel may play a role in the precision of QUS and should be carefully standardized, particularly for longitudinal studies. In addition, following these results we have adopted a standardized protocol to derive the technique reproducibility in groups of premenopausal and postmenopausal women. The coefficients of variation were 1.1% for BUA and 0.1% for SOS in premenopausal women, and 1.4% for BUA and 0.13% for SOS in postmenopausal women.

Adult↗
PubMed1999

Accuracy and precision of 62 bone densitometers using a European Spine Phantom.

Dual-energy absorptiometry (DXA) is widely used for bone mineral density measurements. Different types of devices are available. Differences between devices from either the same manufacturer or different manufacturers can lead to difficulties in clinical practice when patients are followed on different machines. We calculated the accuracy and precision of 62 DXA devices from two manufacturers (51 Hologic, 11 Lunar) using a European Spine Phantom (ESP, semi-anthropomorphic). The ESP was measured 5 times on each device without repositioning. Accuracy was assessed by comparing bone mineral density (BMD, g/cm(2)) values measured on each device with the actual value of the phantom. Precision was assessed by the coefficient of variation (CVsd), using the root mean square average. The limits of agreement were estimated from the differences between each replicate measurement of BMD and the estimated true value for a particular manufacturer, according to Bland and Altman. The results confirm the difference between devices from different manufacturers (18.5%). Mean CVsd values were 0.57% and 0.64% for Hologic and Lunar respectively. The limits of agreement among devices from the same manufacturer were 0.026 g/cm(2) and 0.025 g/cm(2) for Hologic and Lunar respectively. Differences in extreme results between devices from the same manufacturer were on average 5.4% and 3.6% for Hologic and Lunar respectively. Results of different devices from the same manufacturer are highly comparable, although unpredictable differences exist that may be clinically relevant.

Absorptiometry, Photon↗
PubMed1999

Influence of age and sex on vertebral shape indices assessed by radiographic morphometry.

Vertebral shape indices (VSI) assessed by radiographic morphometry are currently used to define vertebral fractures in clinical trials and epidemiologic studies on osteoporosis. However, there is little information concerning the influence of sex or age on VSI. Furthermore, previous reports on the variation of VSI with age showed conflicting results. The aim of this study was to assess the influence of sex and age on VSI in order to better define reference values for the clinical and epidemiologic evaluation of vertebral osteoporotic fractures. Measurements were performed on thoracic and lumbar spine radiographs from 50 men and 50 women (age range 25-75 years) without evidence of osteoporotic, degenerative or other disease-related vertebral deformity. The anterior (AH), middle (MH) and posterior (PH) heights of each vertebral body from T4 to L5 were measured and VSI were calculated as follows: wedging = (AH minus PH) divided by PH; concavity = (MH minus PH) divided by PH. Wedging and concavity, especially at the mid and lower thoracic spine, increased significantly with age in both sexes. We also demonstrated that VSI at the lumbar spine were significantly dependent on gender, with greater values of wedging and concavity in men than in women. Consequently, reference values used for the definition of vertebral osteoporotic fractures assessed by radiographic morphometry should take into account both sex and age effects.

Adult↗
PubMed1999

Cross-sectional study of weight-bearing activity on proximal femur bone mineral density.

In this cross-sectional study we investigated the effect of compressive and tensile forces applied on the proximal femur during weight-bearing activities. Ninety-seven men (29.9 +/- 1.7 years) were divided into two groups: 69 exercisers who had practiced regular high-impact weight-bearing activities for at least 5 years and 28 controls who had been sedentary for at least 5 years. The maximum isometric hip abduction strength was measured. The bone mineral density (BMD) of the femoral neck and the greater trochanter was assessed using dual-energy X-ray absorptiometry (DXA). Controls were considered as the reference population to calculate the Z score. Mean BMD values of the femoral neck were 0.97 g/cm2 on both sides in the exercisers and 0.83 g/cm2 on the right side and 0.84 g/cm2 on the left side in the controls. Mean BMD values of the greater trochanter were 0.86 g/cm2 on the right side and 0.87 g/cm2 on the left side in the exercisers, 0.73 g/cm2 on the right side and 0.72 g/cm2 on the left side in the controls. The BMD was significantly higher in exercisers at both trochanteric and cervical sites (P = 0. 0001). Both left and right hip abduction strength was significantly greater in the exercisers than in the controls (P < 0.05) and was positively correlated to cervical and trochanteric BMD (P < 0.01). In the exerciser group, the trochanteric Z score was higher than the cervical Z score at both right (P = 0.06) and left (P = 0.002) sides. Therefore, the proximal femoral BMD was significantly greater in exercised subjects as compared with sedentary controls. The difference was observed at the level of both the femoral neck (where it is known anatomically that only compressive gravitational forces are exerted) and the greater trochanter (where it is known that tensile forces are exerted). This result suggests the participation of both compressive and tensile forces in the mechanisms by which exercise influences bone trophicity.

Adult↗
PubMed1999

An isolation procedure for arachidonic acid producing Mortierella species.

Malt extract agar and an incubation temperature of 5 degrees C were used to selectively isolate representatives of the genus Mortierella from soil. Fungi in a soil sample from mountain grassland able to grow under these conditions, amounted to a total of 2640 colony forming units per gram soil. Circa 94% of the total fungal isolates represented Mortierella subgenus Mortierella. The rest of the colony-forming units consisted of Mucor isolates (6.0%) and higher fungi (1.5%). All the Mortierella isolates produced arachidonic acid.

Arachidonic Acid↗
PubMed1999

Information fusion: application to data and model fusion for ultrasound image segmentation.

Nowadays, information fusion constitutes a challenging research topic. Our study proposes to achieve the fusion of several knowledge sources. This, in order to detect the esophagus inner wall from ultrasound medical images. After a brief description of information fusion concepts, we propose a system architecture including both model and data fusion. The data fusion is accomplished using fuzzy modeling, which can be seen as a monosensor/multiple sources data fusion system. The model fusion is performed using a full-adapted snake theory, which projects the fuzzy decision into the binary decision space.

Computer Simulation↗
PubMed1999

Individual smallest detectable difference in bone mineral density measurements.

Bone mineral density (BMD) measurement is a major outcome measure in osteoporosis. The BMD changes observed must exceed the variability inherent in the measurement process to be considered related to disease progression. The objective of the study was to estimate short-term variability of BMD measurement and to propose a cut-off value for the smallest detectable BMD changes for an individual. To estimate the short-term variability, 70 healthy postmenopausal women aged 53 +/- 4 years (group 1) and 57 elderly osteoporotic postmenopausal women aged 80 +/- 6 years (group 2) had two repeated BMD measurements of the lumbar spine (L2-L4) and the proximal femur with dual-energy X-ray absorptiometry, with complete repositioning within 1 h. Cut-offs derived from short-term variability were either estimated from the coefficient of variation (CV) (which is a function of the measured value) or from the standard deviation (SD), and applied to 330 postmenopausal women (group 3) who had BMD measurements at baseline and 2 years later. The short-term intrasubject variability was greater at the lumbar spine in group 2 versus group 1 (0.0123 vs. 0.0059 g/cm2, p < 10-4), whereas it was not at the femoral neck (0.0098 vs. 0.0076 g/cm2, p = 0.28). There was no statistically significant correlation between short-term intrasubject variability (SD) and BMD as demonstrated with an analysis of covariance (p values ranging from 0.17 to 0.90). Cut-offs estimated with SD and CV were individually applied to group 3 patients. Using these two cut-offs, discrepancies in assessment of progression were observed in 1.7-8.6% of cases. Short-term BMD variability is constant in a wide range of BMD values. Consequently, to determine cut-off values for the smallest detectable differences in BMD at the individual level, precision errors should be based on SD (expressed in absolute units) rather than on CV (expressed in percentage).

Absorptiometry, Photon↗
PubMed1999

Treatment of patients with Paget's disease of bone.

Paget's disease is a progressive bone disease, monostotic or polyostotic, characterised by hypertrophy of affected bones and accelerated disorganised bone remodelling. It results in bone deformities and pain, with a risk for articular and neurological complications, and fractures. The risk of complications, and thus the therapeutic decision, is a function of the age of the patient, and the severity and the activity of the disease. Bisphosphonates are first-line therapy for Paget's disease, and the advent of the new bisphosphonates permits a dramatic improvement in treatment. The optimal treatment regimen should obtain normalisation or quasi-normalisation of markers of bone remodelling. This result has the potential for a long-term control of the disease.

Biomarkers↗
PubMed1999

Oxidized derivatives of 7-dehydrocholesterol induce growth retardation in cultured rat embryos: a model for antenatal growth retardation in the Smith-Lemli-Opitz syndrome.

7-Dehydrocholesterol accumulates in fetuses affected by the Smith-Lemli-Opitz syndrome as a result of a deficit in the ultimate step of cholesterol synthesis catalyzed by Delta7 reductase. Rat embryos explanted at gestation day 10 and cultured for 48 h in the presence of the Delta7 reductase inhibitor AY 9944 were used as a model to discriminate between the beneficial effect of supplementation with cholesterol and the deleterious effect of supplementation with 7-dehydrocholesterol. Cholesterol supplementation in the form of mixed cholesterol/lecithin liposomes added to serum serving as the culture medium restores the growth of embryos which is markedly decreased in the presence of the inhibitor. 7-Dehydrocholesterol under identical conditions does not restore growth and impairs the beneficial effect of cholesterol added simultaneously. UV-photooxidation of 7-dehydrocholesterol-supplemented culture medium enhances its embryotoxicity, which suggests uptake by the embryo of toxic by-products formed from 7-dehydrocholesterol. By contrast photooxidation of cholesterol-supplemented culture medium does not induce embryotoxicity. alpha-Tocopherol reduces the toxicity of photooxidized 7-dehydrocholesterol supplementing the culture medium. We conclude that 7-dehydrocholesterol does not fulfill the cholesterol requirement of the developing embryos and exerts an additional embryotoxic effect probably via oxidized by-products. This could explain the antenatal growth retardation of SLOS by a blockage of the maternal compensatory cholesterol influx.

Animals↗
PubMed1999

[Quality control in bone densitometry].

Bone densitometry is a biological measurement which must comply to the usual rules of quality control. Calibration phantoms are available and must be regularly measured. Results may be interpreted by visual inspection or by estimating drift percentage. Different calculation methods have been proposed. A rigorous procedure is required when replacing densitometry devices. Simple and regular controls can assure the reliability of the technique.

Absorptiometry, Photon↗
PubMed1999

[Evaluation of post-menopausal osteoporosis using ultrasound].

Quantitative ultrasound (QUS) has recently been proposed for evaluating bone mineral density. Several QUS units are now commercially available. They measure both the attenuation and velocity of the US beam, in a transmission mode, mainly at the calcaneum and phalanges. These parameters are mainly related to bone density, but may also, in theory, be affected by non-quantitative properties of bone such as elasticity and anisotropy. Values measured at QUS are lowered in osteoporotic patients compared to normal control subjects. The predictive value for hip fracture in an elderly population is similar for QUS measurements and conventional techniques of bone mineral density measurements. The reproducibility of measurements with QUS is good, but the variation to be measured is only minimal. Thus, QUS cannot yet be recommended for follow up of patients or evaluation of response to treatment. Technical advances are to be expected. Because this technique is non-invasive and simple, it represents a promising tool for the screening of patients at risk for osteoporosis.

Aged↗