Biomedical subjects

J Caillé

Publications and source records attributed to J Caillé.

13 recordsLinked to original sources

PubMed2002

[13C]aminopyrine and [13C]caffeine breath test: influence of gender, cigarette smoking and oral contraceptives intake.

The [13C]aminopyrine breath test ([13C]ABT) measures the global activity of cytochrome P450 in vivo and is a sensitive indicator of liver metabolic dysfunction. The present study aims to determine whether gender and cigarette smoking influence the results of [13C]ABT as well as to confirm the effect of oral contraceptive steroids (OCS) intake on this metabolic test. Hundred and ten healthy subjects, including men and women, smoker and non-smoker, women taking OCS or not, were phenotyped for CYP1A2 using the [13C]caffeine breath test and underwent a [13C]ABT. Both tests showed large inter-individual variations in accordance with that of CYP450 liver content. [13C]ABT was sensitive enough to point out a significant induction or inhibition related to cigarette smoking habits or OCS. The combined effect of smoking and OCS resulted in an overall unchanged metabolic activity. Consequently, the impact of the studied conditions on the [13C]ABT parameters must be considered by clinicians or clinical investigators.

Aminopyrine↗

PubMed2000

Influence of cognitive strategies on the pattern of cortical activation during mental subtraction. A functional imaging study in human subjects.

Functional magnetic resonance imaging (fMRI) at 1.5 T was used to investigate the influence of cognitive strategies on cortical activation during mental calculation. Twenty-nine right-handed subjects performed a serial subtraction of prime numbers. Even though a common corpus of brain areas was activated during this mental calculation, differences appeared between subjects in function of their spontaneous cognitive strategy. In subjects using a so called verbal strategy (n=15), the main activation was located in the whole left dorsolateral frontal cortex with a little activation of the inferior parietal cortex. In subjects using a so called visual strategy (n=14), a bilateral activation in the prefrontal cortex and a high activation in the left inferior parietal cortex were observed. These results demonstrate that numbers are processed through a distributed network of cortical areas, the lateralization of which is clearly influenced by subject strategy.

Adult↗

PubMed1998

Effect of oral ondansetron on total cholecystokinin plasma levels following CCK-4 panic challenge procedure in healthy men.

OBJECTIVE: To gain insight into whether ondansetron treatment induces changes in total cholecystokinin (CCKT) plasma levels before and after administration of the cholecystokinin tetrapeptide (CCK-4) panic challenge procedure in healthy men. METHODS: Thirty-eight volunteers received a 50-microgram bolus of CCK-4 60 minutes after a single oral dose (acute treatment) and multiple oral doses (chronic treatment) of ondansetron or placebo. RESULTS: Results showed no difference in CCKT plasma levels of CCKT elimination rate constant between the ondansetron and the placebo groups after either acute or chronic treatment. CONCLUSION: Results from this study suggest that total CCK plasma levels are not influenced by either acute or chronic treatment with ondansetron. However, the effect of ondansetron on the different CCK component fractions still needs exploration.

Administration, Oral↗

PubMed1985

Excitation-contraction coupling in skeletal muscle.

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Action Potentials↗

PubMed1979

Evidence for an action of sodium ions in the activation of contraction of twitch muscle fibre.

Simultaneous records in current clamp conditions of potential and of contraction of frog skeletal twitch muscle fibre have shown that a part of the contraction directly depends on the intervention of sodium ions (increase in presence of veratrine, decrease in lithium Ringer). The results confirm previous voltage clamp data and suggest a mechanism of sodium induced calcium release.

Action Potentials↗

PubMed1978

Existence of a sodium current in the tubular membrane of frog twitch muscle fibre; its possible role in the activation of contraction.

1. The membrane current of frog twitch muscle fibre has been recorded together with contraction in the test gap of a double sucrose gap apparatus. 2. In Ringer, the inward current sometimes shows 2 phases with the same threshold and the same reversal potential: a rapid one (early inward current) and a slower one (late inward current). The mechanical threshold is near the inward current threshold. The amplitude of the contraction increases progressively with depolarizations, without modification of its time to peak. Experiments with variation of the pulse duration and with conditioning depolarization show that a part of the contraction seems to be correlated with the late inward current. 3. Experiments in a sodium free solution, with low TTX concentration, and on glycerol treated fibres show that the late inward current corresponds to a tubular sodium current. 4. A method is described to separate the two phases of inward current. The smooth development of the current-voltage relation of the late inward current, its diminution without modification in time to peak under the action of TTX, and the exponential decay of its tail current all suggest that the tubular membrane potential is sufficiently well controlled. 5. In the experiments where the tubular membrane potential seems to be controlled, a part of the contraction depends on the tubular sodium current, perhaps involving a mechanism of sodium induced calcium release.

Animals↗

PubMed1975