Biomedical subjects

J Frutoso

Publications and source records attributed to J Frutoso.

22 records · Page 2Linked to original sources

PubMedDate not supplied

Soleus muscle alterations in spontaneously hypertensive rats are not dependent on activation of beta 2-adrenergic receptors.

The effects of selective beta 2-adrenergic blockade with ICI 118,551 on the histochemical, biochemical, and contractile properties of slow-twitch soleus muscle from spontaneously hypertensive (SHR) and normotensive (WKY) rats were examined from birth to 8-10 weeks of age. Chronic treatment of normotensive rats with ICI 118,551 caused an impairment in the differentiation of slow type fibers during development but failed to alter the fiber type distribution of hypertensive rats. beta 2-Adrenoreceptor blockade was ineffective in reducing the enhanced glycolytic and oxidative capacities of soleus in hypertensive rats. The suggestion can be made that beta 2-adrenoreceptor activation is not responsible, at least directly, for the histochemical and biochemical alterations of slow muscle from hypertensive rats.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

Effect of acute atenolol on short-term blood pressure variability and baroreflex sensitivity in rats.

Beta-blocker therapy for hypertension or coronary artery disease is common, but there are a lot of controversies about its effects on short-term blood pressure variability and arterial baroreceptor reflexes. The aim of this study was to evaluate the effects of acute atenolol on baroreflex sensitivity (BRS) and on the spontaneous variability of systolic blood pressure (SBP) and RR intervals in conscious rats. Ten Wistar rats equipped with telemetry system were evaluated: 1) under control conditions; 2) after injection of saline; and 3) during beta1-adrenergic blockade by atenolol. Fast Fourier transform analysis was applied to RR intervals and SBP. Atenolol increased RR intervals significantly by 14% and the variation coefficient of the RR intervals by 31%. SBP was reduced significantly by 9%. In frequency domain, beta1-blockade in RR intervals increased very low frequency by 33% and the total power by 22% and decreased low frequency by 25%. The ratio of low to high frequency power decreased by 60%. Frequency domain variables in SBP were not significantly changed after beta1-adrenergic receptor blockade. BRS (gain alpha) was not significantly altered by beta-blockers. Acute atenolol decreased SBP and increased RR intervals with no change in BRS, indicating 'resetting' of baroreflex function.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

[The determination of the intensity of premolar and molar maximal forces during the isometric contraction of the masticatory muscles due to forced mandibular closure].

The purpose of this study to quantify the activity of the masticatory muscles. For this we recorded the maximum bite force of opposing teeth during voluntary clenching. The study was carried out on 31 students aged 21 to 28 with a satisfactory dental arch. The measurements were obtained on one side only. Nine thickness of the traducers were used for the premolar zone and two for the molar zone. We determined an optimal thickness enabling the highest measurement: 6.5 mm for the premolars and 5.2 for the molars. The highest measurements were averaged and the following results were obtained: premolars-35 kgf for females and 50 kgf for males; molars 100 kgf for females and 130 kgf for males.

Adult↗

PubMedDate not supplied

[The demonstration of a relation between premolar force and molar force within the limits of a simplified approach to masticatory system functioning].

The purpose of this study is to show the existence of a correlation between the premolar and molar clenching forces obtained during a voluntary clenching exercise. The study concerned 32 volunteers aged 21 to 28 with no manducatory problems. The forces were obtained using a device with four Kiowa traducers arranged in a complete Wheatstone bridge. The analysis of the results obtained showed that there was a positive correlation between maximum molar and premolar. The analysis also shows that three results are a direct application of the theory of momentum. This enables us to propose a simple biophysical model to explain the functioning of the masticatory system.

Adult↗