[Research strategies in the evaluation of depressive states]. / Stratégies de recherche dans l'évaluation des états dépressifs.

The present paper discusses the respective benefits of a latent trait model and of factorial correspondence analysis in the research strategies of depression inventory construction. Results on the processing of the same list of depressive symptoms by both analyses are presented. The fact that, in questionnaires based on latent models, each answer brings an information closely dependent on its place in the hierarchical order is underlined. The latent trait strategy construction offers an accurate way to assess how patients recover from depression.

Measuring the severity of depression through a self-report inventory. A comparison of logistic, factorial and implicit models.

The present study investigates the psychometric adequacy of a self-report inventory of depression (the QD2) with respect to the severity of depressive symptoms, within the framework of a unidimensional model of depressive states. Responses to the 52 QD2 items, by 481 subjects divided into four groups (depressed, psychiatric, somatic and control), were subjected to a Rasch analysis. Results show that 15 items (QSD(R1] display a satisfactory goodness of fit for both items and persons, as defined by the Rasch model. This set of items, solely related to 'pure' depression, gives a measure of the severity of depression, free from anxiety symptoms. The discussion focuses upon the advantages of the Rasch model as compared to traditional tests. The Rasch 15-item solution should provide a parsimonious tool for future studies on the classification of depressive disorders.

Sheep: a model for testing spinal and epidural anesthetic agents.

The sheep was utilized as a model to study local anesthetic agents used for subarachnoid and epidural anesthesia in human beings. Employing injection and evaluation technics similar to those used in human anesthesiology, the onset of anesthesia, development of maximum sensory anesthesia, regression of sensory anesthesia, and complete return of sensation and motor function were measured. Subarachnoid injection with 0.25% tetracaine and epidural injection with 0.25% bupivacaine produced regional anesthesia similar to that observed in humans.

Effects of topical and general anesthetic agents on tracheal mucous velocity of sheep.

Tracheal mucous velocity was estimated in eleven sheep by means of cine-bronchofiberscopic technique in which Teflon discs placed on the tracheal mucosa were filmed as markers. The procedure was done using a transnasal approach in conscious nonanesthetized sheep, and in the same sheep using topical and/or general anesthetic agents. The average mucous velocity in conscious sheep was 17.3 plus or minus 6.2 (SD) mm/min; in sheep anesthetized with intravenous pentobarbital or thioamylal, the average velocity was significantly depressed to 11.1 plus or minus 3.6 mm/min. No Significant differences in tracheal mucous velocity were found when 10 ml of 2 percent lidocaine was instilled into the tracheas of either conscious sheep or sheep under general anesthesia. Sheep as an animal model appear to be ideal in the study of the responses of tracheal mucous velocity to physical and chemical agents since they tolerate bronchofiberscopy quite well without the use of topical or general anesthetic agents. The basis for the depression of tracheal mucous velocity by barbiturates cannot be ascertained from the present study but the model should be useful for comparing different types of anesthetic agents.