[Can bite force be predicted from the shape of the face?]. / La force d'occlusion peut-elle prédire la forme de la face?

The relationships between maximum bite force (MBF) and facial architecture have been tested in a sample of 118 dental students. The strongest correlations were seen with the variables representative of posterior face height and facial divergence. No correlation could be seen between MBF and incisor's position. MBF allowed only partial discrimination of the individuals in different subgroups constituted by cluster analysis. MBF is to consider as a representation of the individual aptitude to develop more or less powerful forces. It summarises only part of the functional information influencing facial form.

Protective effect of nedocromil sodium on the dual asthmatic response to bronchial antigen challenge.

The effects of nedocromil sodium and placebo on the asthmatic response to antigen bronchial provocation were studied in a double-blind, randomized, crossover trial. Twelve subjects sensitized to Dermatophagoides pteronyssinus were challenged with successive doubling doses of this allergen (1.25-80 x 10(-3) mg) on two separate occasions, at least 15 days apart. A single dose of either nedocromil sodium 4 mg, or, a matching placebo was given 30 min before challenge. Forced expiratory volume in 1 s (FEV1) was measured 5, 10 and 15 min after challenge. Early asthmatic response was analyzed using three indices: dose producing a 20% decrease in FEV1 (PD20), the slope of and area under the dose-response curve. Nedocromil sodium was significantly superior to placebo with respect to all three indices, providing significant inhibition of the early asthmatic responses. Seven of the 12 patients showed a late asthmatic response. There was no significant difference between the effects of nedocromil sodium and placebo treatments on the decline in peak expiratory flow rate (PEFR) during the late asthmatic response but it should be noted that when patients had been treated with nedocromil sodium they were receiving two to eight times the dose of allergen given after placebo treatment.

Prolonged submaximal exercise and L-carnitine in humans.

Changes in the main physiological parameters and circulating indicators of carbohydrate, protein, lipid (and ketone body) metabolism were measured in ten exercising subjects before L-carnitine (L-carn) loading, after 4 weeks of daily loading with 2 g L-carn, and 6-8 weeks after terminating L-carn administration. Measurements were made on venous blood samples collected during each experiment at fixed time intervals over an initial rest of 45 min, 60 min bicycle exercise performed near 50% VO2max and 120 min recovery. Free and total plasma carnitine levels reached a plateau corresponding to an average rise of 25% for both fractions, 9-10 days after the beginning of the L-carn diet. These levels returned to their initial values 6-8 weeks after cessation of the supply. Generally L-carn supplementation did not significantly modify the physiological parameters and circulating metabolites. No distinct increase of the relative participation of endogenous lipids in the fuel supply of prolonged submaximal exercise was observed. In normal human subjects the increased demand for fatty acid oxidation resulting from exercise seems to be adequately supported by endogenous levels of carnitine.

Allergen bronchial challenge tests: variability and reproducibility of the early response.

We evaluated allergen bronchial challenge tests (ABCTs) variability and reproducibility during 2-week intervals, respectively, in 28 and 14 Dermatophagoides pteronyssinus-sensitized patients. Increasing doses of Dpt (1.25 to 160 X 10(-3) mg) of lyophilized Dpt extract were administered at 20-minute intervals by doubling the previous dose. Dose-response curves (D-RC) were constructed for each test with the logarithm (base 2) of the allergen dose and the FEV1 in milliliters as ordinate. We analyzed different indices: the allergen doses causing a 15% decrease in FEV1 (PD15) and a 20% decrease in FEV1 (PD20), the slope of the curve beyond PD15, the overall slope, and the area under the parabolic curve. We found considerable intersubject variability in early asthmatic responses to Dpt ABCTs. Bronchoconstriction induced by allergen produced a specific D-RC for each individual. PD20 was significantly correlated with all the indices representing the whole D-RC (i.e., overall slope and area); moreover, PD20 was found on the steepest portion of the curve in 24 of 28 D-RCs. With the methodology used, we obtained a satisfactory reproducibility in a 2-week interval: the linear slope obtained by log base 2 transformation of doses was highly reproducible (p less than 0.001), as was area p under the parabolic curve. PD20 is significantly reproducible in a range of one doubling dose (twofold variation). The reproducibility of ABCTs over a short period permits solid arguments for their use in the evaluation of prophylactic treatment and in clinical research.

A study of the criteria used for clinical evaluation of prophylactic treatment in bronchial asthma.

In an attempt to find better criteria for the evaluation of prophylactic treatment of asthma, we have studied the significance and the correlations of the 3 parameters usually measured: symptoms, bronchodilator requirements, changes in Peak Expiratory Flow (PEF). We have collected these data daily over a 16 week period in 13 adult asthmatics allergic to Dermatophagoides pteronyssinus. For each patient, the 3 scores were compared graphically. Linear regression was used to analyze the individual relationship between 2 daily scores. Incomplete cards mostly revealed unexpected behaviour (e.g. normal lung function but many symptoms recorded) and cannot of course be taken into account in a trial protocol. We found a good correlation between PEF and symptom scores in 10 out of 13 patients and we could point out the poor correlation between medication score and the other scores. To our knowledge, it is the first time such an objective result has been shown in asthmatic adults. Our analysis provides data which should improve the studies of prophylactic treatment efficacy in asthma.

Clinical and immunologic evaluation of tyrosine-adsorbed Dermatophagoides pteronyssinus extract: a double-blind placebo-controlled trial.

We evaluated the clinical efficacy and immunologic changes associated with the administration of tyrosine-adsorbed Dermatophagoides pteronyssinus (Dpt) extract. The study was carried out in a double-blind, placebo-controlled fashion in 18 patients with Dpt-induced asthma during a trial period of at least 12 mo. Patients initially received six increasing doses once a week; the top dose of 400 Noon units was repeated at monthly intervals. Clinical response was on the basis of diary cards on which symptoms and medication scores were recorded; daily lung function measurements were made by use of a mini Wright's peak flow meter. The entire spectrum of physiologic measurements, medications, and symptoms were taken into account by computing daily scores over a 2-week period. Total IgE, Dpt-specific IgE antibodies, and leukocyte histamine release were measured before treatment and during hyposensitization. Changes in Dpt-specific IgG were evaluated with a double antibody antigen-binding assay by use of the purified fraction of mite extract F4P1. All patients had measurable levels of IgG antibodies to F4P1 before treatment. Treatment with tyrosine-adsorbed Dpt extract resulted in a significant increase of specific-IgG antibodies in the treated group at 2 and 6 mo only (nonparametric rank sum test). Variations relative to the pretreatment values of total and specific IgE were not significantly different in the treated and in the control patients after 2.6 and 12 mo. No significant decrease in leukocyte sensitivity was observed after treatment. It was only possible to demonstrate a significant diminution in the mean medication score (nonparametric sign test) in the first 6 mo for the treated group; independently of the beginning of the treatment, the treated group demonstrated a reduction of the mean medication score and an improvement in peak expiratory flow rate lung function before the midsummer months when seasonal increase in mite density can occur. Particular attention was paid to the methodological problems raised during this study and inherent in a trial in house dust-mite asthma.