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Biomedical subjects

R Lacroix

Publications and source records attributed to R Lacroix.

At least 19 recordsLinked to original sources
PubMed2001

A case-acquisition and decision-support system for the analysis of group-average lactation curves.

A case-acquisition and decision-support system was developed to support the analysis of group-average lactation curves and to acquire example cases from domain specialists. This software was developed through several iterations of a three-step approach involving 1) problem analysis and formulation in consultation with two dairy nutrition specialists; 2) development of a case-acquisition and decision-support prototype by the system developer; and 3) use of the prototype by the domain specialists to analyze and classify milk-recording data from example herds. The overall problem was decomposed into three subproblems: removal of outlier tests and lactation curves of individual cows; interpretation of group-average lactation curves; and diagnosis of detected abnormalities at the herd level through the identification of potential management deficiencies. For each subproblem, a software module was developed allowing the user to analyze both graphical and numerical performance representations and classify these representations using predefined linguistic descriptors. The example-based method for the development of the program proved to be very useful, facilitating the communication between system developer and domain specialists, and allowing the specialists to explore the appropriateness of the various prototypes developed. The resulting software represents a formalization of the approach to group-average lactation curve analysis, elicited from the two domain specialists. In future research, the case-acquisition and decision-support system will be complemented with knowledge to automate identified classification tasks, which will be captured through the application of machine-learning techniques to example cases, acquired from domain specialists using the software.

Animals↗
PubMed2000

Nausea and vomiting during pregnancy: A prospective study of its frequency, intensity, and patterns of change.

OBJECTIVE: Our purpose was to provide a detailed description of patterns of nausea and vomiting of pregnancy. STUDY DESIGN: A prospective study was performed with 160 women who provided daily recordings of frequency, duration, and severity of nausea and vomiting. RESULTS: Seventy-four percent of women reported nausea lasting a mean of 34.6 days. "Morning sickness" occurred in only 1.8% of women, whereas 80% reported nausea lasting all day. Only 50% of women were relieved by 14 weeks' gestation; 90% had relief by week 22. Data based on the McGill Nausea Questionnaire indicate that the nausea experienced by pregnant women is similar in character and intensity to the nausea experienced by patients undergoing cancer chemotherapy. CONCLUSIONS: Traditional teachings about nausea and vomiting of pregnancy are contradicted by our findings. Standardized tools for measuring the distribution, duration, and intensity of nausea are applicable to the study of nausea and vomiting of pregnancy and could be used in clinical trials to assess palliative measures.

Adult↗
PubMed1998

Nonlinear neural mapping analysis of the adverse effects of drugs.

Numerous drugs have been identified as presenting adverse effects towards the driving of vehicles. A large set of these drugs was compiled and classified into ten categories. Nonlinear neural mapping (N2M) was used to derive a typology of these molecules and also to link their adverse effects to therapeutic categories and structural information.

Automobile Driving↗
PubMed1997

Phantom limbs in people with congenital limb deficiency or amputation in early childhood.

It is widely believed that people who are congenitally limb-deficient or suffer a limb amputation at an early age do not experience phantom limbs. The present study reports on a sample of 125 people with missing limbs and documents phantom experiences in 41 individuals who were either born limb-deficient (n = 15) or underwent amputation before the age of 6 years (n = 26). These cases provide evidence that phantom limbs are experienced by at least 20% of congenitally limb-deficient subjects and by 50% of subjects who underwent amputations before the age of 6 years. The phantoms are detailed and can be described in terms of size, shape, position, movement and temporal properties. The perceptual qualities of the phantoms can also be described by sensory descriptors and are reported as painful by 20% of subjects with phantoms in the congenital limb deficient group and 42% of young amputees. It is argued that these phantom experiences provide evidence of a distributed neural representation of the body that is in part genetically determined.

Adolescent↗
PubMed1996

[Cockett syndrome. Initial results with percutaneous treatment in 6 patients].

Intimal hypertrophy with venous spur formation caused by compression of the left common iliac vein by the right common iliac artery is advanced as the etiology of the higher incidence of deep venous thrombosis involving the left leg. In most cases of left iliofemoral thrombosis no underlying compression syndrome is detected or treated because the left common iliac vein has to be cleared from thrombi before compression can be identified. A series of 6 consecutive retrospectively analyzed patients with acute left iliofemoral thrombosis is presented. In these patients a left iliac vein compression syndrome was detected after percutaneous intraluminal thrombolysis with Actilyse (rt-PA). This compression was successfully relieved by insertion of a wall stent. Percutaneous treatment of Cockett's syndrome seems an attractive alternative for conservative and/or surgical management.

Adult↗
PubMed1996

[Proposition of chemical topology of principal antiviral molecules by a multiparameter mathematic model: the minimal length graph].

The developed formula of some 200 antiviral molecules were treated by molecular connectivity matrix method. This technic allows the search and the automatically count of structural binary fragments of these molecules. It has been possible to establish a spanning tree (Prim's arborescent squeleton) which gathers the different molecules and permits to put a priori some new structures.

Antiviral Agents↗
PubMed1995

A phylogenetic analysis of monocotyledons based on the chloroplast gene rps4, using parsimony and a new numerical phenetics method.

We have sequenced the chloroplast gene rps4 of 72 species; the sequence of 6 more species was found in the databanks. The 78 species were chosen so as to be representative of two taxonomic levels: the family, with 39 Poaceae, and the class, with 28 additional monocot species. Eleven dicots and other land plants were used as outgroups to the monocots. The 78 sequences were aligned by eye. Phylogenetic reconstruction was performed using the Wagner parsimony method: our first results were in contradiction with classical systematics, due to a local minimum. We then used the results obtained with the new distance method Anataxis to redraw a new tree and carry on further the parsimony calculations starting from this Anataxis tree. Up to 20,000 most parsimonious trees were thus obtained. The robustness of our results was checked by the bootstrap test and decay analyses. The Anataxis and the strict consensus tree fitted the general features of land plant evolution. Some of our results concerning relationships within the monocots corroborated those obtained with the chloroplast gene rbcL. Both genes raise questions concerning the monocot superorders as defined in a previous classification. This study proves the rps4 gene to be a useful phylogenetic tool within the Poaceae family and the Monocotyledonae order.

Base Sequence↗
PubMed1993

[Multiparameter approach to undesirable effects of drugs that may represent risk for the automobile driving].

Drugs part in traffic accidents is not well known. We attempted to specify it taking out of pawn the adverse effects which could be liable: drowsiness; consciousness lose; dizziness; eye-sight troubles; hallucinations, hearing troubles; drunken feelings, behaviour modification; propensy to suicide, interference with alcohol. Drugs involving such effects were indexed; their therapeutic indications and their chemical structure were taking into account. Statistical classical count allowed us to quantify relative importance of this ten adverse effects category. Multivariate analysis worked out structuration this undesirable effects into 97 different profiles by the mean of the Minimum Spanning Tree method and established proximity links between the 409 active principles recorded. This results are reported here.

Automobile Driving↗
PubMed1992

Pain-elicited responses and their role in predicting future pain duration and severity.

The first objective of this study was to carry out a prospective investigation of the behavioral and affective responses to headache pain over a 72 hr period. A sample of 74 headache sufferers provided self-reported ratings of affective and behavioral responses as measured by a composite of standardized questionnaires. Highly significant and clinically meaningful levels of both types of responses were found on the headache day. Interestingly, significant levels of behavioral and affective disturbances were also reported 24 hr after pain termination, indicating that responses to pain actually outlasted pain perception by at least 1 day. The second goal of this study was to investigate whether affective or behavioral responses were predictors of future pain intensity, duration or severity. A smaller sample of 25 subjects provided ratings on two sequential headaches. A series of time-lag analyses indicated that, unlike behavioral responses, strong affective responses during a given episode were associated with subsequently longer and more severe headaches. These results suggest that affective pain-elicited responses may be a risk factor for suffering a worse headache during the episode that follows.

Adaptation, Psychological↗
PubMed1992

Multiple phantom limbs in a child.

This case report describes multiple phantom feet in a child after amputation of a leg. The subject is a 16-year-old girl who was born with a right leg 10 cm shorter than the left and who at the age of 6 was amputated below the right knee so that she could wear a prosthesis that would give her normal mobility. The girl reports that she subsequently experienced 2 phantom feet and 3 sets of phantom toes which have persisted to the present time. Each phantom has a distinct size, length and position in relation to the others and each is also the site of vivid sensations such as heat, tickle, and fatigue as well as voluntary and involuntary movement. She also describes sensations that resemble sensations experienced before the amputation: one of her phantom feet feels flat and locked into a forward position which corresponds with the actual shape and position of her congenitally deformed amputated foot. The implications of multiple phantoms are discussed with reference to recent concepts of phantom limbs.

Adolescent↗
PubMed1992

[Structural typology assay of principal anticancer agents on the basis of molecular fragmentation].

The developed formula of 58 anticancer agents used in therapeutic or still in clinical essays were treated by molecular connectivity matrix method. This technic allows the search and the automatically count of structural fragments of the different studied molecules. Then it has been possible to build a spanning tree (Prim's arborescent skeleton) which gathers the different molecules and permits to put a priori new structures.

Antineoplastic Agents↗
PubMed1992

[Overall analysis of structural factors responsible for the activity and toxicity of antiparasitic agents used in therapy].

A mini-data bank was constituted from the 73 french antiparasitic patent medicines and was implanted in microcomputer. A maximum of chemical, pharmaceutical, therapeutical and toxicological data were collected and treated by multivariate analysis. Exploitation of these informations processing allows to take out correlations between chemical structure toxicity, and specificity.

Anthelmintics↗
PubMed1991

Labor pain: effect of maternal position on front and back pain.

The purpose of this study was to determine whether women in labor report less pain when they are in a vertical (sitting or standing) position than in a horizontal (side-lying or supine) position. Pain scores were obtained from 60 women in early labor (dilation 2-5 cm) who alternated between the two positions. The results show that about 35% of women feel less front pain and 50% feel less back pain when they are in a vertical position than in a horizontal position. The decrease in continuous back pain (83%) was particularly impressive, but the front and back pains associated with contractions were significantly diminished as well. These results, taken together with those of earlier studies, indicate that many women in early labor have less pain and are generally more comfortable in a vertical than in a horizontal position. Since early labor comprises a substantial proportion of the entire process of labor and delivery, any simple procedure which alleviates pain without danger to mother or child, such as shifting from a horizontal to a vertical position, should be promoted and employed.

Adolescent↗
PubMed1990

The impact of recurrent headaches on behavior lifestyle and health.

The goal of this study was to examine whether behavioral avoidance was pervasive in a sample of headache sufferers as has been suggested by Philips (Behavior Research and Therapy, 25, 273-279, 1987). One hundred and fifty participants provided retrospective evaluations of behavior changes perceived to have resulted from repeated exposure to headache pain. The outcome of these self-assessments underscored marked changes in several domains of behavior and overall lifestyle. This evidence therefore provided support for Philips' position since the changes appeared persistent, even during pain-free states.

Adaptation, Psychological↗
PubMed1989

[Multiparameter analysis approach of antiparasitic structure-activity relationships in function of the parasite taxonomy].

In this paper the authors have studied the structure-parasitic activity relationships through the Chemical Abstracts data base which groups together the works published in this field for the last twenty years. With mathematical methods of multidimensional data reduction using a computer it has been possible to validate the classification of human parasites on the base of their sensitivity to chemical families. The specificity of the pharmacochemical relationships was described through two factorial maps. This work shows that it is possible to find new chemical series with potential parasitic activity.

Animals↗
PubMed1986

[Role of psychotic factors in asthma].

The specific psychological field of patients suffering from asthmatic disease or from allergic disease has been very often observed. This research based on the study of 29 patients the psychological profile of whom had been first assessed and for which the psychological factor seemed to be determining in the setting off the manifestations of hypersensitivity allows us to draw our attention to the notion of a common metabolic cause. The systematic study of the metabolism of the tryptophan seems to confirm a deviation of the latter to the production of a some mediator favourable to the apparition or the revelation of the classical triad: - asthma, allergy, psychotic state.

Adult↗