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Biomedical subjects

F Aubry

Publications and source records attributed to F Aubry.

At least 19 recordsLinked to original sources

Expression and regulation of the CC-chemokine monocyte chemoattractant protein-1 in rat testicular cells in primary culture.

Testicular inflammation is classically observed in pathogenesis caused by infectious agents, environmental toxins, trauma, or autoimmune reactions and can lead to transitory or even permanent sterility. In these situations, a leukocyte infiltration is generally encountered. Macrophage inflammatory proteins (MIP)-1alpha and -1beta and monocyte chemoattractant protein-1 (MCP-1) are CC-chemokines involved in macrophage and lymphocyte chemoattraction. In the present study, using reverse transcription-polymerase chain reaction, Northern blot, and a specific ELISA, we investigated whether or not these chemokines are present within the testis and whether they are induced by a number of proinflammatory cytokines and lipopolysaccharides (LPS). MIP-1alpha and MIP-1beta were not detected in Sertoli cells, germ cells, peritubular cells, or Leydig cells. In contrast, MCP-1 mRNA and protein were found to be expressed by control isolated peritubular cells, and expression was markedly stimulated by interleukin-1alpha and-1beta (IL-1alpha and IL-1beta), tumor necrosis factor alpha (TNF-alpha), interferon gamma, and LPS. Leydig cells expressed MCP-1 when stimulated by IL-1beta. In contrast, MCP-1 was not found to be produced by Sertoli cells or germ cells as established by Northern blot and ELISA techniques. The kinetics of MCP-1 production by peritubular cells, as demonstrated by expression as early as 8 h poststimulation, are compatible with there being a rapid mobilization of these cells and this chemokine in an inflammatory process. Moreover, MCP-1 production by peritubular cells after half-maximal stimulation by LPS, TNF-alpha, and IL-1beta (2 pg/ml-0.9 ng/ml) is also compatible with the physiologic concentrations of the proinflammatory cytokines generally found in an inflammatory site. It is concluded that MCP-1 is produced by Leydig cells and peritubular cells and that it could be involved in the mobilization and migration of leukocytes observed during testicular inflammation.

Animals↗

[Towards the integration of the digital medical image folder within the computerized patient folder: PACS and image networks].

Medical Images are components of the so-called "Medical Imaging Folder". This folder is a subset of the so-called "Medical Folder", part of the "Patient Folder. The G8 promotes the concept of a "Global Information Society for Health. Within this society, the Patient Folder is seen either from a healthcare organization, from a country or from an international point of view. The Global Patient Folder (Healthcare Folder) is composed of the different Patient Folder instances. Presently, Pacs and Telemedicine are no longer concerned only by storage and transmission issues. The medical images have only meaning associated with their context, the patient healthcare status. This context is rich in information provided by various information systems or healthcare professionals. The different data are linked and time dependant. Therefore, the expert community in the field of patient records argues that the approach must be the integration of Medical Images within the patient folder. It appears clearly that the complete deployment of such an "International Healthcare Folder" needs time and will proceed in several steps. Due to the increase of the people's mobility this deployment is inescapable. Infrastructure must be sized up taking into account the Digital Medical Image spreading and its large data volume which necessitates a large bandwith. In this paper, we detail the Medical Image Folder concept and its position within the Patient Folder and the Healthcare Folder. Then we present PACS, networking and Telemedicine concepts as well as the needs in standards.

Humans↗

Mi-2 complex couples DNA methylation to chromatin remodelling and histone deacetylation.

Methylation of DNA at the dinucleotide CpG is essential for mammalian development and is correlated with stable transcriptional silencing. This transcriptional silencing has recently been linked at a molecular level to histone deacetylation through the demonstration of a physical association between histone deacetylases and the methyl CpG-binding protein MeCP2 (refs 4,5). We previously purified a histone deacetylase complex from Xenopus laevis egg extracts that consists of six subunits, including an Rpd3-like deacetylase, the RbA p48/p46 histone-binding protein and the nucleosome-stimulated ATPase Mi-2 (ref. 6). Similar species were subsequently isolated from human cell lines, implying functional conservation across evolution. This complex represents the most abundant form of deacetylase in amphibian eggs and cultured mammalian cells. Here we identify the remaining three subunits of this enzyme complex. One of them binds specifically to methylated DNA in vitro and molecular cloning reveals a similarity to a known methyl CpG-binding protein. Our data substantiate the mechanistic link between DNA methylation, histone deacetylation and transcriptional silencing.

Adenosine Triphosphatases↗

Identification of a human 17p-located cDNA encoding a protein of the Snf2-like helicase family.

Following immunoscreening, we have cloned and sequenced a human cDNA encoding a novel member of the expanding helicase family. The deduced protein, designated hZFH (human zinc-finger helicase), contains the seven domains conserved among the helicase superfamily II and four potential zinc-fingers motifs. In particular, hZFH shows significant similarity to some proteins of the Snf2-like family, known to act as transcriptional regulators for multiples genes. Furthermore, hZFH has 68.5% identity to a human Mi-2 autoantigen to which autoantibodies are produced by a subgroup of patients affected by dermatomyositis. Northern-blot analyses have revealed several hZFH mRNAs with quantitative differences in various human tissues. One alternative splice site of hZFH mRNA was demonstrated and others were predicted. We also report the chromosomal localization of gene hZFH to locus 17p13-17p12 by in situ hybridization. Thus, this novel gene appears as a candidate for several malignant and genetic diseases associated with this region of the genome. The combination of these features suggests that hZFH plays an important role in gene regulation.

Adenosine Triphosphatases↗

Standardization in the field of medical image management: the contribution of the MIMOSA model.

This paper deals with the development of standards in the field of medical imaging and picture archiving and communication systems (PACS's), and notably concerning the interworking between PACS's and hospital information systems (HIS). It explains, in detail, how a conceptual model of the management of medical images, such as the medical image management in an open system architecture (MIMOSA) model, can contribute to the development of standards for medical image management and PACS's. This contribution is twofold: 1) Since the model lists and structures the concepts and resources involved to make the images available to the users when and where they are required, and describes the interactions between PACS components and HIS, the MIMOSA work helps by defining a reference architecture which includes an external description of the various components of a PACS, and a logical structure for assembling them. 2) The model and the implementation of a demonstrator based on this model allow the relevance of the Digital Imaging and Communications in Medicine (DICOM) standard with respect to image management issues to be assessed, highlighting some current limitations of this standard and proposing extensions. Such a twofold action is necessary in order both to bring solutions, even partial, in the short term, and to allow for the convergence, in the long term, of the standards developed by independent standardization groups in medical informatics (e.g., those within Technical Committee 251 of CEN: Comité Européen de Normalisation).

Diagnostic Imaging↗

Chromosomal localization and expression pattern of the RNase L inhibitor gene.

2-5A-Dependent RNase (RNase L), an important component of the 2-5A pathway, is directly implicated in the molecular mechanism of interferon action. We have cloned and sequenced following immunoscreening, a full-length cDNA that encodes the RNase L inhibitor (RLI). Northern blot analysis from a variety of human tissues revealed that two transcript forms (3.8 kb and 2.4 kb) are ubiquitously expressed but differences in levels of expression suggest a tissue-specific regulation. The RLI gene was localized to locus 4q31 by in situ hybridization indicating that this gene and other enzymes of the 2-5A pathway are not organized in cluster in the human genome.

ATP-Binding Cassette Transporters↗

[Management and transmission of medical images. Main standards and norms].

Use of digital images is growing in medical imaging. To be efficient, up-to-date concepts such as distributed informatics and client/server architecture must be used. Interoperability and networks adapted to the data involved in medical imaging are prerequisites to the implementation of such concepts. This necessitates official and de facto standards. Users of medical imaging should be aware of these standards and insist on the implementation of such standards on imaging equipment. This paper presents a survey of the main standards suitable for medical image management and transmission. Particular attention is focused on DICOM which is becoming the worldwide recognized standard in the field of medical imaging.

Diagnostic Imaging↗

[White fingers].

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Fingers↗

[A diabetic foot].

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Diabetic Foot↗

[Anti-beta 2 glycoprotein 1 antibodies in idiopathic livedo reticularis].

INTRODUCTION: Idiopathic livedo reticularis can be a sign of systemic disease since certain complications are frequently associated: cerebral thrombotic events in Sneddon's syndrome, necrotic ulcerations of the lower limbs. Antiphospholipid antibodies have been found in 0 to 85 p. 100 of patients with Sneddon's syndrome and anti-beta 2-glycoprotein 1 antibodies in 65 p. 100 of a series of 20 cases with Sneddon's syndrome. The aim of our study was to determine the prevalence of anti-beta 2-glycoprotein 1 antibodies in idiopathic livedo reticularis. PATIENTS AND METHODS: Twelve patients in a series of 17 with idiopathic livedo reticularis seen between 1981 and 1992 were studied progressively. All underwent a clinical examination and simple laboratory tests with search for anticardiolipin antibodies, lupus type circulating anticoagulant and anti-beta 2-glycoprotein 1 antibodies. RESULTS: Eight of our 12 patients (60 p. 100) were positive for anti-beta 2-glycoprotein 1 antibodies, 3 of whom also had episodes of thrombosis similar to those described in antiphospholipid syndrome. Only one of the 8 patients also had anticardiolipin antibodies and no chronic manifestation of thrombosis. DISCUSSION: beta 2-glycoprotein 1 is a cofactor which increases anticardiolipin antibody adhesion to cardiolipin in ELISA. Anti-beta 2-glycoprotein 1 antibodies are associated with thrombosis and antiphospholipid antibodies with lupus. Our results would suggest that the prevalence of anti-beta 2-glycoprotein 1 antibodies is high in idiopathic livedo, but, due to the small number of patients, do not allow confirmation that anti-beta 2-glycoprotein 1 antibodies are associated with thrombosis. Anti-beta 2-glycoprotein 1 antibody assay would be justified in routine evaluation of patients with livedo and at follow-up examinations.

Adult↗

Redistribution of nuclear antigens linked to cell proliferation and RNA processing in mouse oocytes and early embryos.

We have systematically analyzed by indirect immunofluorescence the subcellular distribution of nuclear antigens in relation to developmental stages of maturing mouse oocytes and developing embryos. Antigens were of two types: (1) a protein whose nuclear localization in interphase somatic cells depends on their proliferative state protein recognized by a monoclonal antibody 43B1N, and (2) snRNP polypeptides recognized by autoimmune sera of anti-Sm and anti-RNP type. The protein recognized by 43B1N was present in the germinal vesicle of oocytes from antral follicles, but absent from the nuclei during the first hours of embryonic life up to the middle to late 2-cell stage. Starting from this stage, it was always found in nuclei of interphase blastomeres, where its "speckles" co-localized with the speckles containing high concentrations of snRNP polypeptides. SnRNP polypeptides recognized by anti-Sm and anti-RNP sera were in turn found in nuclei of all developmental stages. When embryos were treated with aphidicolin or cytochalasin D to arrest cell division, the 43B1N reacting protein was again localized in the pronuclei at 42 hr post-hCG, i.e., slightly later than the onset of transcriptional activity. These results suggest a progressive building up of nuclei during embryonic development, which could influence gene expression.

Animals↗

Risk factors of squamous cell carcinoma of the skin. A case-control study in the Montreal region.

A matched case-control study was undertaken to assess the relative risk associated with known and suspected risk factors of squamous cell carcinoma of the skin among patients in the Montreal region. Three hundred eleven cases histologically diagnosed in 1977 and 1978 in 12 hospitals and meeting strict definition criteria were identified. With the exception of six cases, two controls were matched to each case for sex, age, and hospital of diagnosis. A logistic regression analysis was done. The known host risk factors (eye and hair color, complexion, descent) and nonoccupational sunlight exposure were found to be operative in the Montreal region. After adjusting for these factors, occupational sunlight exposure appeared to be a risk factor. An association was then observed between the risk of squamous cell carcinoma of the skin and tobacco smoking and the use of a sunlamp. Relative risks associated with the above-mentioned factors were estimated.

Age Factors↗

Factor analysis of 81mKr lung ventilation studies.

Factor analysis of dynamic structures (FADS) summarizes data depending on time and space in a few elementary components. Each of them associates a time-activity curve (factor) and the spatial distribution of the corresponding events. The aim was to evaluate the patterns, the number of components, and their possible link to physiology when FADS was applied to scintigraphic images representing a composite of a 81mKr ventilation cycle. In a study of 26 patients (10 normal, 16 pathologic), components were found that represent: (1) a rapid and steeply changing ventilation factor, corresponding mainly to bases in normal subjects and whole lung fields in patients, (2) a slower expiration and shorter inspiration ventilation factor distributed throughout both lung fields in all patients, (3) a constant activity curve, with an inspiratory activity peak distributed over both lung fields and the large airways, and (4) a factor including a phase shift with respect to the first; this was found significantly more often in patients with pathology.

Factor Analysis, Statistical↗

Sister chromatid exchanges in Chinese hamster V79 cells treated with the trivalent chromium compounds chromic chloride and chromic oxide.

The induction of sister chromatid exchanges (SCEs) in Chinese hamster V79 cells exposed to soluble CrCl3 and insoluble Cr2O3, compounds of trivalent chromium (Cr3+), was determined. Their ability to induce SCEs was compared with those of three hexavalent chromium (Cr6+) compounds: K2CrO4, Na2CrO4 and Na2Cr2O7. Both the delay in progression through the cell cycle induced by Cr3+ compounds and the SCE frequencies in the delayed cells were also evaluated. The exposure for 28 h to CrCl3 and Cr2O3 at concentrations of 9.7-39 micrograms and of 34-136 micrograms of Cr3+ per ml, respectively, induced a statistically significant (p less than 0.001) dose-dependent increase in SCEs up to 1.9-fold (CrCl3) and 4-fold (Cr2O3) over control levels. Compared with the effective concentrations of Cr6+ compounds, which produced up to 4-fold increase of SCEs, inducing concentrations of CrCl3 and Cr2O3 were 300- and 1000-fold higher in terms of chromium. By prolongation of treatment time up to 48 h, a progressive dose- and time-related enhancement in SCE frequencies induced by Cr3+ compounds in delayed cells was observed. Lower concentrations of Cr2O3, without effect after 28 h of treatment, induced an increase of SCEs by prolongation of exposure time.

Animals↗

[Use of tomographic scintigraphy with radio-labelled monoclonal antibodies for detecting human digestive cancers and medullary cancers of the thyroid].

Two 131-Iodine radiolabelled monoclonal antibodies were used to perform tomoscintigraphy in 42 patients: 11 patients bearing medullary thyroid cancers and 19 patients bearing gastrointestinal cancers received an antibody directed against carcino-embryonic antigen; 12 patients bearing gastro-intestinal cancers received an antibody directed against a non circulating antigen expressed by human colorectal cancers cell lines. Tomoscintigraphy is particularly useful for analysing the complex biodistribution of radiolabelled antibodies and the low contrast images encountered in immunoscintigraphy; the problems related to the true positive rate and to the clinical specificity of the method are discussed.

Antibodies, Monoclonal↗