What is the real practice of exercise echocardiographic testing in asymptomatic patients with severe aortic stenosis?

Background: Although exercise testing has been suggested to help predict clinical outcome, limited data are available to guide how exercise Doppler echocardiography (ECG) can be used clinically in asymptomatic patients with aortic stenosis (AS). The aim of this study was to assess the clinical value of exercise echocardiographic testing in asymptomatic patients with severe AS.

Methods: Symptom-limited treadmill exercise testing using the modified Bruce protocol was performed in 31 asymptomatic patients (mean age (62 ± 11) years) with severe AS (aortic valve area <1 cm(2), peak aortic velocity (AV Vmax) >4 m/sec, or a mean transaortic pressure gradient (AV mean PG) >40 mmHg (1 mmHg = 0.

[Induction of cytochrome P 450 by phenobarbital in cats].

Phenobarbital administration to the Cat an animal hypersensitive to the actions of many toxic substances or to physiological compounds such as hormones, does not produce cytochrome P 450 induction. Consequently, hepatic storage of retinol remains unchanged. The specific and original characteristics of the Cat in this field are underlined by these results.

[Joint effects of dietary protein levels and vitamin A additions on the induction of cytochrome P450 by DDT in rats].

A 5 P. 100 level of protein from casein in a diet does not allow vitamin A to modify significantly induction of cytochrome P 450 on the Rat receiving or not receiving DDT. When the protein increases to a 15 p.

[Difference in the sensitivity of the hamster and the rat to the effects of long-term administration of ethylenethiourea].

Rats and hamsters were fed ETU at levels of 0, 5, 17, 60, 200 mg/kg in the diet. Body weights, food consumption, seric enzyme activities (GPT, alkaline phosphatase), hepatic enzyme activities (GPT, alkaline phosphatase G6PDH), cholesterolemia, thyroid weight and others organs, histology were the criteria studied. ETU was found causing hypercholesterolemia for the 2 species at 5 mg/kg dietary levels.

Use of the golden hamster in toxicology.

The choice of an appropriate species and strain of laboratory animal is one of the toxicologist's major concerns. The biochemical, anatomical, and other characteristics of the golden hamster which make it a valuable though limited tool in toxicologic research were reviewed. The effects of organochloride insecticides on rats, mice, and hamsters were compared.