Biomedical subjects

Y Rolland

Publications and source records attributed to Y Rolland.

At least 91 records · Page 5Linked to original sources

PubMed1996

[Multimodal approach to carotid bifurcation in atherosclerosis].

The cost of treatment of ischemic stroke (second cause of death for elderly patients) is increasing. carotid bifurcation surgery can change the prognosis (as proven by NASCET and ECST studies) for symptomatic patients with over 70% of carotid narrowing. Exploration of the carotid bifurcation is an important step in the diagnosis and must assess the degree of stenosis, the smoothness of the plaque and describe the collateral vessels. Duplex sonography is used to analyze the plaque and to measure the hemodynamic consequences beyond the stenosis. Transcranial Doppler is used to study the hemodynamic consequences at the circle of Willis. 3D TOF MR Angiography visualizes vessels using MIP but with a risk of overestimation of the degree of stenosis. A good morphological study of the circle of Willis can be achieved. With spiral CT, 3D data bases can be acquired with a single injection of contrast medium. Analysis is based on native, reformatted and MIP images. The image quality is generally good, but decreases in the case of huge calcifications. Brain examination can be performed in the same session, looking for rupture of the blood-brain barrier. Angiography remains the gold standard with a high complication rate. It allows excellent analysis from the aortic arch to distal cortical vessels. Isotope studies are only performed in difficult cases (vertebro-basilar lesions, differential diagnosis). Duplex ultrasound is performed first in all protocols. Until recently, angiography was performed before surgery, but the current tendency is to use a less invasive examination (MR angiography or CT angiography) and angiography is then only performed when necessary. A knowledge of the respective advantages of each technique is essential in order to adapt the protocols to each local team.

Angiography, Digital Subtraction↗

PubMed1995

Chlorpromazine inhibits nitric oxide-mediated increase in intracellular cGMP in a mouse teratocarcinoma cell line.

Chlorpromazine is a phenothiazine with a structure similar to that of methylene blue. Since methylene blue is a well known inhibitor of nitric oxide-induced cyclic GMP accumulation, we investigated whether chlorpromazine had the same effect. Cyclic GMP accumulation, induced in a mouse teratocarcinoma cell line (P19) by sodium nitroprusside (a nitric oxide releasing agent), was inhibited by both methylene blue (IC50 0.34 microM) and chlorpromazine (IC50 35 microM). Chlorpromazine's action was probably directed specifically at soluble guanylate cyclase, since the drug had no effect on ADP-ribosylation in rat hippocampus, another nitric oxide-affected, but cGMP-independent event.

Adenosine Diphosphate Ribose↗

PubMed1995

Synthesis and evaluation of 3',5'-di-tert-butyl-4'-hydroxyflavones as potential inhibitors of low density lipoprotein (LDL) oxidation.

The novel flavones 6-28, which display structural analogies with the two well-known lipid peroxidation inhibitors, probucol [1] and butylated hydroxytoluene [2], were synthesized and studied in vitro for their ability to inhibit the copper sulfate or endothelial cell-induced lipid peroxidation of human low-density lipoprotein (LDL). Most of the flavones were active in the range of 0.1-1 microM.

Antioxidants↗

PubMed1995

New phenotype of the cerebral autosomal dominant arteriopathy mapped to chromosome 19: migraine as the prominent clinical feature.

A survey was carried out on a large family presenting the symptoms of familial arteriopathy (CADASIL) recently mapped to chromosome 19. This is characterised clinically by recurrent subcortical infarcts developing into pseudobulbar palsy and subcortical dementia, and radiologically by early MRI abnormalities. To characterise this familial condition, 43 members older than 20 years and spreading over four generations were studied clinically (31 living, 12 deceased), genetically, and radiologically by MRI (n = 31). Twenty out of 43 were found to be clinically symptomatic and of these 13 out of 31 had MRI abnormalities. Genetic studies mapped this condition to the locus of CADASIL (lod score > 3). The natural history suggests a chronological clinicoradiological staging of this phenotype of CADASIL: stage I between 20 and 40 years with frequent migraine-like episodes and well delineated lesions of the white matter; stage II between 40 and 60 years with stroke-like episodes, bipolar or monopolar-like psychotic disorders, coalescent lesions of the white matter, and well delineated lesions of the basal ganglia; and stage III over 60 years with subcortical dementia, pseudobulbar palsy, diffuse leukoencephalopathy, and multiple well delineated lesions of the basal ganglia. This phenotype differs from the other two previously described by high frequency of migraine, frequency of psychotic disorders, and early neurological manifestations. The new acronym "cerebral autosomal dominant arteriopathy with subcortical infarcts, leukoencephalopathy, and migraine" (CADASILM) is proposed to better describe this particular subvariety of CADASIL.

Adult↗

PubMed1995

Synthesis and antifungal activities of some new triazolylacetophenone derivatives.

In this study some alpha-(1,2,4-triazolyl)acetophenone derivatives were synthesized by the condensation of various triazole and alpha-bromoacetophenone rings. The structures of the compounds have been elucidated by UV, IR, 1H-NMR, mass spectra and elementary analysis. The in vitro antifungal activity of the compounds were investigated against some yeast-like fungi (Candida albicans, C. parapsilosis, C. stellatoidea and C. pseudotropicalis) and moulds such as Trichophyton rubrum and T. mentagrophytes by the tube dilution method and MIC (minimal inhibitory concentration), MFC (minimal fungicidal concentration) values were determined. Compound A16 was significantly more effective than the other compounds. The results obtained for antifungal activity against moulds were not significant.

Acetophenones↗

PubMed1995

Synthesis and inhibitory activities on platelet aggregation of some flavonoid analogues.

A series of 26 benzodioxan and benzodioxol derivatives of flavone have been prepared. The activity of the compounds on washed human platelet aggregation induced by adenosine diphosphate (ADP, 5 mumol/l), collagen (10 micrograms/ml) and calcimycin (20 mumol/l) was evaluated. The alkoxycarbonyl side chain derivatives inhibited all three types of aggregation inducers. Among the tested compounds Ia is the most potent inhibitor of collagen-induced aggregation but possesses a weak activity against the other two used inducers. The esters IIIb and in particular, IIIc are active against all the three used inducers. These results suggest that ethoxycarbonyl group is a potent substituent to provide the antiplatelet action in this series of flavonoids.

Flavonoids↗

PubMed1995

Opercular malformations: clinical and MRI features in 11 children.

Opercular malformations are rare and complex brain malformations for which only very fragmented neuropathological descriptions have been reported. They are related to an abnormal development of both sylvian fissure and frontoparietal operculum. We report a retrospective clinical and MRI study of 11 patients presenting with opercular malformations. A congenital pseudobulbar syndrome was observed in six cases, various motor disorders in seven cases, mental retardation in six cases and epilepsy in four cases. The purpose of this study is to evaluate the main features of opercular malformations in children and to try to characterise this entity on the basis of its clinical features and MRI pattern.

Cerebral Cortex↗

PubMed1995

[Analysis of texture in medical imaging. Review of the literature].

This paper presents a review of the applications of texture analysis in medical imaging. Many authors take a great interest in this topic (75 papers have been published since 1984) and try to elaborate automatic methods for tissue characterization. The results are not really convincing and applications are often reduced to feasibility studies. This failure is due to the empirical approach to the problem: the first studies were performed on ultrasound images, in which visual texture is very present, but no data standardization is available with this imaging modality. A more rational approach should provide better results. For each organ or tissue, it is necessary to find the appropriate source and texture analysis method. This difficult task requires reflection concerning the interactions between tissues and imaging sources, to define judicious structuring elements. These structuring elements should facilitate the choice of the best texture analysis method, for the particular application. Considerable methodological progress has yet to be made, after which texture analysis should be a useful and efficient tool for clinical use.

Humans↗

PubMed1995

[Glossary of terms used by radiologists in image processing].

We give the definition of 166 words used in image processing. Adaptivity, aliazing, analog-digital converter, analysis, approximation, arc, artifact, artificial intelligence, attribute, autocorrelation, bandwidth, boundary, brightness, calibration, class, classification, classify, centre, cluster, coding, color, compression, contrast, connectivity, convolution, correlation, data base, decision, decomposition, deconvolution, deduction, descriptor, detection, digitization, dilation, discontinuity, discretization, discrimination, disparity, display, distance, distorsion, distribution dynamic, edge, energy, enhancement, entropy, erosion, estimation, event, extrapolation, feature, file, filter, filter floaters, fitting, Fourier transform, frequency, fusion, fuzzy, Gaussian, gradient, graph, gray level, group, growing, histogram, Hough transform, Houndsfield, image, impulse response, inertia, intensity, interpolation, interpretation, invariance, isotropy, iterative, JPEG, knowledge base, label, laplacian, learning, least squares, likelihood, matching, Markov field, mask, matching, mathematical morphology, merge (to), MIP, median, minimization, model, moiré, moment, MPEG, neural network, neuron, node, noise, norm, normal, operator, optical system, optimization, orthogonal, parametric, pattern recognition, periodicity, photometry, pixel, polygon, polynomial, prediction, pulsation, pyramidal, quantization, raster, reconstruction, recursive, region, rendering, representation space, resolution, restoration, robustness, ROC, thinning, transform, sampling, saturation, scene analysis, segmentation, separable function, sequential, smoothing, spline, split (to), shape, threshold, tree, signal, speckle, spectrum, spline, stationarity, statistical, stochastic, structuring element, support, syntaxic, synthesis, texture, truncation, variance, vision, voxel, windowing.

Diagnostic Imaging↗

PubMed1994

Synthesis and evaluation of 9-hydroxy-5-methyl-(and 5,6-dimethyl)-6H-pyrido[4,3-b]carbazole-1-N- [(dialkylamino)alkyl]carboxamides, a new promising series of antitumor olivacine derivatives.

Starting from 2-(2-aminoethyl)-6-methoxy-1-methylcarbazole, ethyl 9-methoxy-5-methyl-6H-pyrido[4,3-b]carbazole-1-carboxylate was obtained through a three-step sequence. This compound and its 6-methyl derivative react with (dialkylamino)alkylamines to provide various 9-methoxy-5-methyl-6H-pyrido[4,3-b]carbazole-1-(N-substituted carboxamides) whose boron tribromide demethylation afforded corresponding 9-hydroxy-1-(N-substituted carbamoyl)-olivacines. The same pathway but starting from 2-(2-aminoethyl)-6-methoxy-1,4-dimethylcarbazole led to ethyl 9-methoxy-5,11-dimethyl-6H-pyrido[4,3-b]carbazole-1-carboxylate which did not normally react with amines. It provided either the recovered starting material at 120 degrees C or 9-methoxyellipticine resulting from an unexpected decarboethylation in a steel vessel at 180 degrees C. Biological testing of the newly obtained 1-carbamoylolivacine derivatives showed that 9-hydroxylated compounds displayed high cytotoxicity for cultured L1210 and colon 38 cells (IC50 range 5-10 nM) and good antitumor activity in vivo in the P388 leukemia and colon 38 models when administered by the iv route. The most active compound in these series is 9-hydroxy-5,6-dimethyl-1-[N-[2-(dimethylamino)ethyl]carbamoyl]-6H- pyrido[4,3-b]carbazole which was selected for further evaluation on murine solid tumors and for toxicological studies.

Adenocarcinoma↗

PubMed1994

[Aspects and value of MRI in the diagnosis and follow-up of common microbes infectious spondylodiscitis. Apropos of 25 clinically and biologically suspected patients].

This work is about 25 patients clinically and biologically suspected of spondylodiscitis (27 levels). All of them had a MRI exam before disco-vertebral needle biopsy and treatment. The results are compared to those of literature. Each infectious spondylitis case (19 cases) had a new MRI exam each three months. This study conclude to the great sensibility of MRI (89%) in the diagnosis of infectious spondylitis and to the limited interest of it in the follow-up of spondylodiscitis.

Adolescent↗

PubMed1994

[Evaluation of the scanner and radiography in rheumatic pelvispondylitis].

We studied 20 normal subjects and 20 suffering from sacro-iliitis. The performance of the two techniques were compared in studying reports ROC curve from several readers. We assessed the performance of each technique and each sign: CT scan appears as a better technique than plain films. Some signs present a poor interest: osteophytes seen on CT or plain films, subchondral cysts seen on CT. In other respects, articular cartilage erosions, subchondral sclerosis are main signs as much on CT as on plain films. In conclusion, CT scan allowed an accurate analysis of sacro-iliitis. It has a better diagnostic value than plain films and, in case of doubt, should be performed to increase diagnosis sensibility and specificity.

Adult↗

PubMed1993

Effect of activation of the serotoninergic system during prolonged starvation on subsequent caloric intake and macronutrient selection in the Zucker rat.

Starvation or dietary restriction are known to modify post-fasting dietary self-selection. We have examined the effects of activation of the serotoninergic system and food deprivation on macronutrient self-selection following a period of starvation. Rats were starved for 4 days and either treated or not with dl-fenfluramine or fluoxetine. Starved untreated animals showed a post-fasting anorexia and an increased preference for carbohydrate intake, even though lipids remained the preferred source of calories. Treatment with fenfluramine or fluoxetine increased post-fasting anorexia, abolished the preference for carbohydrates and decreased lipid intake. Fluoxetine, but not fenfluramine, resulted in decreased protein intake as well. Following a 2-day refeeding period ad libitum, during which the animals were not treated with drugs, the anorectic effect of fenfluramine disappeared but that of fluoxetine remained unchanged. In addition, we noted that at an equimolar dose to dl-fenfluramine (100 mumol/kg/day) fluoxetine treatment resulted in the death of all the animals in the group by the second day of refeeding; no deaths were observed in any of the other groups. In conclusion, we confirm a post-starvation anorexia and increased carbohydrate intake following long-term fasting. In addition we show that activation of the serotoninergic system abolishes the increase in carbohydrate intake and potentiates post-starving anorexia.

Animals↗

PubMed1993

Radiological findings in three cases of persistent müllerian duct syndrome.

We report three cases of persistent Müllerian duct syndrome, which is a rare form of inherited male pseudohermaphroditism characterized by the presence of a uterus and tubes in otherwise normally virilized 46,XY males. We emphasize the usefulness of ultrasonographic study of the pelvis and inguinal areas in the preoperative diagnosis, which is difficult. We recommend that ultrasound be performed routinely in bilaterally cryptorchid patients.

Adolescent↗

PubMed1993

[Fusion of data. Multimodality in neurological imaging].

The development of tomographic imaging methods, which provide anatomical and functional information in a digital form, has transformed the approach to the central nervous system. Patient management is now frequently based on fusion of data from the same or different modalities, which potentiates the performance of each technique. These fusions were initially performed manually on film supports, but are now increasingly performed by consultation stations which process digital data bases. In view of the increasing demands for data fusion, it has become necessary to develop, in parallel with these new techniques, image transmission networks and visualisation stations on which reconstructions and fusions are performed. Improvements in software should facilitate acquisition techniques which should increasingly resemble standard techniques. The logistic applied must also be as simple as possible in order to be widely implanted and easy to use.

Central Nervous System Diseases↗

PubMed1992

Akuammine and dihydroakuammine, two indolomonoterpene alkaloids displaying affinity for opioid receptors.

Akuammine [1], an indolomonoterpene alkaloid, which is the major component of the seeds of Picralima nitida, was reduced to dihydroakuammine [4]. This compound has structural analogy with eseroline [7], for which affinity for opiate receptors was reported. The present investigation showed that 1 and 4 also bind (with lower affinity however) to mu and kappa opiate receptors. 1H- and 13C-nmr spectra of 1 and 4 have been fully assigned by 2D nmr experiments.

Alkaloids↗

PubMed1992

US-guided percutaneous liver biopsy with plugging of the needle track: a prospective study in 72 high-risk patients.

The efficiency, accuracy, and safety of ultrasound-guided liver biopsy with plugging of the needle track were prospectively assessed in 72 patients at high risk for hemorrhage. Seventy-eight biopsy procedures were performed in 72 consecutive patients prospectively classified into four different groups on the basis of coagulation parameters. Sixty-two patients (86%) had severe or moderately severe coagulation disorders. Fifty-four biopsy procedures were performed in 50 patients with diffuse liver disease, and 24 were performed in 24 patients with focal liver lesions. The biopsy track was embolized with gelatin particles and thrombin. Biopsy specimens adequate for histologic diagnosis were obtained in 69 of the 72 patients (96%). In focal lesions, accuracy and sensitivity in the diagnosis of malignancy were 75% and 89%, respectively. Two serious bleeding complications (2.8%) were encountered in two of the patients with major coagulation disorders. Liver biopsy with plugging of the needle track is a practical technique and is a feasible alternative to the transjugular approach. Respective indications for both methods depend on the severity of coagulation disorders and the presence of focal lesions.

Adult↗

PubMed1990

Contribution of MRI to the diagnosis of ACTH-secreting pituitary adenomas. Exploration of 9 patients with Cushing's disease.

Between June 1987 and October 1989, nine patients with suspected Cushing's disease were explored by magnetic resonance imaging (MRI), using an 0.35 or 0.5 Tesla magnet. All these patients underwent transsphenoidal surgery and radio-surgical correlations could be established. MRI showed a lesion in 5 cases; it was negative in 2 cases and doubtful in 2 cases. Surgery was positive for pituitary adenoma in 7 cases and negative in 2 cases (including 1 patient with subsequently discovered paraneoplastic syndrome). Using sagittal and coronal planes and combined with gadolinium enhancement, MRI proved to be the most sensitive and specific of all exploratory methods for the diagnosis of ACTH-secreting pituitary adenomas.

Adenoma↗