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Biomedical subjects

F Aubry

Publications and source records attributed to F Aubry.

At least 37 records · Page 2Linked to original sources
PubMed1985

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↗
PubMed1985

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↗
PubMed1983

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↗
PubMed1983

[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↗
PubMed1982

Tomoscintigraphy for detecting gastrointestinal and medullary thyroid cancers: first clinical results using radiolabelled monoclonal antibodies against carcinoembryonic antigen.

Transaxial tomoscintigraphy (or single-photon emission computerised tomography) was used to detect secondary deposits of carcinoma in 17 patients who had been injected with iodine-131-labelled monoclonal antibodies against carcinoembryonic antigen. Of 17 tumor sites studied by tomoscintigraphy 16 were detected (sensitivity 94%); five sites had a volume smaller than 10 cm3. Tomoscintigraphy also detected three unknown tumour deposits later confirmed by surgery or radiology. In contrast, when 21 tumour sites in the same patients were studied by rectilinear scintigraphy, only nine tumour sites were detected (sensitivity 43%), of which eight had a volume larger than 50 cm3.

Antibodies, Monoclonal↗
PubMedDate not supplied

A medical image object-oriented database with image processing and automatic reorganization capabilities.

The paper presents the medical image database developed for use in the methodological research environment and in the laboratory clinical environment, designed to be capable of being interfaced to an image processing system. This database is intended to solve the numerous problems due to the complexity-multidimensionality and multimodality-of medical images. These problems are posed in terms of management, archiving, structuring and accessing of this archive, and specification of the interfaces with users and with image processing system Solving these problems involves making a formal description of the image and the data associated with the image, while taking into account the specifics of medical imaging. The kernel which contains this description allows the physical architecture of the management and archiving system to be decoupled from its logical architecture. This decoupling is essential in order to automate the recording of new data, the automatic reorganization of the system scheme in the event of change in the system environment, and to help in consulting the database.

Algorithms↗
PubMedDate not supplied

Air pollution and health in three urban communities.

A health study was conducted in three communities in the greater Montreal region; the first two were characterized by relatively high particulate and sulfur dioxide levels, respectively, and a third community without major industrial pollution. In each community, 300 men and women 45 to 64 yr of age were studied. Residents of the two more polluted communities exhibited a higher prevalence of respiratory symptoms and mean lung function evaluated by various tests was lower than in residents of the less polluted community. When intercity differences in age and smoking were accounted for, no statistically significant intercity differences in health status could be shown. Given the limitations of this study, the results provide no evidence to suggest that current Canadian standards for sulfur dioxide adequately protect human health as measured by the indices used in the study, for adults in the age range of 45 to 64 yr.

Air Pollutants↗
PubMedDate not supplied

Design and implementation of a biomedical image database (BDIM).

We developed a biomedical image database (BDIM) which proposes a standardized representation of value arrays such as images and curves, and of their associated parameters, independently of their acquisition mode to make their transmission and processing easier. It includes three kinds of interactions, oriented to the users. The network concept was kept as a constraint to incorporate the BDIM in a distributed structure and we maintained compatibility with the ACR/NEMA communication protocol. The management of arrays and their associated parameters includes two distinct bases of objects, linked together via a gateway. The first one manages arrays according to their storage mode: long term storage on optionally on-line mass storage devices, and, for consultations, partial copies of long term stored arrays on hard disk. The second one manages the associated parameters and the gateway by means of the relational DBMS ORACLE. Parameters are grouped into relations. Some of them are in agreement with groups defined by the ACR/NEMA. The other relations describe objects resulting from processed initial objects. These new objects are not described by the ACR/NEMA but they can be inserted as shadow groups of ACR/NEMA description. The relations describing the storage and their pathname constitute the gateway. ORACLE distributed tools and the two-level storage technique will allow the integration of the BDIM into a distributed structure, Queries and array (alone or in sequences) retrieval module has access to the relations via a level in which a dictionary managed by ORACLE is included. This dictionary translates ACR/NEMA objects into objects that can be handled by the DBMS.(ABSTRACT TRUNCATED AT 250 WORDS)

Database Management Systems↗
PubMedDate not supplied

A database manager of biomedical images.

In order to allow an efficient archiving and retrieval of biomedical images, PACS would include an image DBMS. As biomedical images have complex structures we developed a specific DBMS over a relational one. The medical image database manager ensures a data description that takes into account data semantics so that consistency or existential constraints may be verified. It provides a unique language to retrieve images no matter what their storage format. It encompasses the queries of the user which constitute a filter over associated data. The manager can handle changes in the environment of the image. We implemented a manager prototype to show the validity of logical access possibilities. The user need no longer know the structure of the image database to access data. The logical access allows retrieval of images, whatever the architecture of the base. An automatic query construction consists of three functional levels including the interfaces towards the external environment which ensure a logical independence from the database, a query generator which creates the correspondence between the user's query and physical access queries, a dictionary which contains the structure of the image data and consistency constraints.

Computer Systems↗
PubMedDate not supplied

MIMOSA: a functional model of the management of medical images.

The concept of picture archiving and communication system (PACS) appeared in 1982. Twelve years later most PACS prototypes still do not satisfy the medical community requirements: too much emphasis has been put on technical solutions and little effort devoted to the management of images itself. A common approach to this problem is needed more than ever to allow cost-effective systems to be developed. Modelling is a way to reach this objective, and the MIMOSA topic within the AIM/EurlPACS project aims at defining such a model of medical image management. This paper presents the MIMOSA approach with the three underlying constraints, i.e. genericity, implementation independence and performance. The MIMOSA group is building three interrelated models: a data model, a functional model and a dynamic model. However, in this report we focus only on the functional model, and explain how it was abstracted from various clinical scenarios in the first phase of the project. The availability level concept is introduced as a customizable and implementation independent solution to the problem of managing the delay of access to the information. The so-called contextual diagram and the acquisition of a new examination which are two representative parts of the model are detailed. The validation aspects and the relationships to projects working on the management of patient records are addressed as a conclusion.

Computer Systems↗