Search results for "muscles"
showing 10 items of 616 documents
Pentachlorophenol accumulation in the freshwater mussels Anodonta anatina and Pseudanodonta complanata, and some physiological consequences of labora…
1995
Freshwater mussels Anodanta anatina and Pseudanodonta complanata were exposed to (14C)-pentachlorophenol. The wet weight based bioconcentration factor (BCF = activity in animal per activity in water) at steady state varied from 80 to 120 for A. anatina and from 61 to 85 for P. complanata. The species did not differ significantly in their wet weight or lipid based BCFs but dry weight based values were significantly higher (40-50%) for A. anatina. The soft tissue dry weight and dry weight based condition index of A. anatina (Cl4 = soft tissue dry weight per shell length) differed significantly between natural mussel populations. In animals kept from 4 to 8 months in laboratory conditions, the…
Kinetics of in vivo inhibition of tissue cathepsin d by pepstatin A
1988
1. 1. We have investigated the kinetics of inhibition of cathepsin D in heart, liver and skeletal muscle of CD-1 mice following administration of 25, 50, 100 and 200 mg/kg i.p. of pepstatin A, a specific inhibitor of this protease. 2. 2. In the liver, a significant inhibition of cathepsin D occurred up to at least 15 days, whereas, in heart and skeletal muscle, this inhibition lasted for a much shorter period of time. 3. 3. These results show that the recovery of enzyme activity to normal values is dose-dependent and that, at the same dose level, marked differences occur in the recovery of enzyme activity in these organ tissues, the liver being the most sensitive one. © 1988.
Evolution of the complex permittivity of biological tissue at microwaves ranges: Correlation study with burn depth
2014
The evolution of the muscle tissue's complex permittivity represents a growing interest in terms of characterization in medicine and biology. The influence of a burned part on the permittivity is not very developed. In this work, an estimation of the complex permittivity of biological tissues is performed as a function of the depth of burn tissues. The sensor, an open-ended coaxial probe, is placed directly against each sample. The evolution of the complex permittivity is studied for two measurements conditions (in the air and in a physiological solution). A correlation study is attempted with the depth of burn tissue.
Kinetische Analyse der Calcium-Kompartimente im Meerschweinchenherzen unter Kontrollbedingungen und Strophanthineinwirkung
1974
A quantitative analysis of myocardial Ca-metabolism was carried out on isolated, isovolumetric (10 ml/min) perfused guinea pig hearts by combined determinations of the total Ca-content and kinetics of 45Ca-efflux (collecting period 60 min) (Fig. 1). The kinetics of 45Ca-uptake was estimated by extrapolating 45Ca-efflux curves of heart muscles isotopically loaded for different times (2, 5, 10, 30 60 min) to the end of the loading-period (Fig. 2).
Temperature dependence of the toxic effects of phenytoin on peripheral neuromuscular function of the rat tail.
1990
We studied the acute effects of a single dose of phenytoin (250 mg/kg) on peripheral neuromuscular function. The evoked muscle action potentials of the dorsal segmental muscles in the rat tail, and the conduction velocity of the dorsal nerve trunk which innervates them, were measured before and after the intraperitoneal injection of phenytoin. The experiments were performed at different temperatures, 27 (physiological tail temperature), 36 and 37 degrees C (physiological central temperature) in different groups of animals. The amplitudes of the evoked muscle action potentials in the treated groups showed no significant modifications at 27 degrees C, at 36 degrees C a small nonsignificant de…
Effets de la pratique de l'escalade sur la contractilité musculaire
1992
Resume Les caracteristiques biomecaniques des flechisseurs du coude et du poignet de sujets grimpeurs sont comparees a celles de sujets non pratiquants. Les mesures sont realisees a l'aide d'un ergometre isocinetique sur une plage de vitesses angulaires s'etalant de 120°·s −1 en excentrique a 360°·s −1 en concentrique. Les relations couple maximum/vitesse angulaire montrent que les sujets grimpeurs developpent un couple maximum plus eleve que les sujets temoins sur une plage de vitesse angulaire allant de 60°·s −1 en excentrique a 120°·s −1 en concentrique. Les differences entre les valeurs de couple maximum excentrique et concentrique sont identiques pour les deux groupes de sujets. Lors d…
In vivo investigations on microcirculatory disturbances induced by crenated erythrocytes following norepinephrine application
1974
Using a special apparatus for high resolution cinephotomicrography, which allows simultaneous observation and recording of microcirculatory changes, alterations in blood flow patterns and in red cell shape during norepinephrine acting have been studied. Under physiological conditions, and during slowing of capillary blood flow due to gradual removing of 20–25% of the circulating blood volume, the normal red cells are extremely deformable while passing through mesenteric capillaries. After application of norepinephrine a general arteriolar constrictive response in the bowel wall occurs, causing a further slowing of the capillary blood flow in the mesentery. Under these circumstances the eryt…
Force-, power-, and elasticity-velocity relationships in walking, running, and jumping
1980
Ground reaction forces and mechanical power were investigated when the subjects walked normally, while they were racing or running at four speeds, and when they performed the running long jump take-off. In addition, the apparent spring constants of the support leg in eccentric and concentric phases were investigated at the four running speeds, during the running long jump take-off, and in the triple jump. Six club level track and field athletes, four national level long jumpers, and six national level triple jumpers took part in the study. Cinematographic technique and a mathematical model of hopping (Alexander and Vernon 1975) were employed in the analysis. Force and power values were foun…
MICROWAVE EFFECTS ON ACETYLCHOLINE-INDUCED CHANNELS IN CULTURED CHICK MYOTUBES
1988
The behavior of cultured myotubes from chick embryos exposed to microwaves has been experimentally analyzed. Recordings of acetylcholine-induced currents have been obtained via patch-clamp techniques using both cell-attached (single-channel current recording) and whole-cell (total current recording) configurations. During the exposure to low-power microwaves the frequency of the ACh-activated single channel openings decreased, while the ACh-induced total current showed a faster falling phase. Channel open time and conductance were not affected by microwave irradiation. It is concluded that the exposure to microwaves increases the rate of desensitization and decreases the channel opening pro…
6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase from frog skeletal muscle: purification, kinetics and immunological properties.
1993
Fructose 2,6-bisphosphate is the most potent activator of 6-phosphofructo-1-kinase, a key regulatory enzyme of glycolysis in animal tissues. This study was prompted by the finding that the content of fructose 2,6-bisphosphate in frog skeletal muscle was dramatically increased at the initiation of exercise and was closely correlated with the glycolytic flux during exercise. 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase, the enzyme system catalyzing the synthesis and degradation of fructose 2,6-bisphosphate, was purified from frog (Rana esculenta) skeletal muscle and its properties were compared with those of the rat muscle type enzyme expressed in Escherichia coli using recombinant DN…