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Biomedical subjects

J Caroff

Publications and source records attributed to J Caroff.

At least 19 recordsLinked to original sources
PubMed1992

Standardization in the determination of red blood cell polyamines by high-performance liquid chromatography.

The choice of the standardization method in the high-performance liquid chromatographic determination of dansyl polyamines (spermidine and spermine) in red blood cell extracts is discussed. 1,6-Hexanediamine, commonly used as an internal standard, is unsuitable for the quantification of spermidine and spermine in red blood cells because their percentage recoveries are significantly different (100% for 1,6-hexanediamine, and 70% for spermidine and spermine). The external standard method and the standard addition method are better suited. The procedure for the preparation of the standard mixture before dansylation has an influence on the values of red blood cell polyamines. Two procedures are compared and the corresponding percentages of variation were found to be high for spermidine and spermine. Thus the procedure in which the standard is treated in a strictly similar way as the red blood cells is certainly the most appropriate one for the quantification.

Chromatography, High Pressure Liquid↗
PubMed1992

[Neurotransmission and sudden infant death. Study of cerebrospinal fluid].

The study of 33 cerebrospinal fluids of infants victims of sudden death shows a very significant increase of the metabolites of dopamine and serotonin. These determinations, compared to a control group, indicate a failure, concerning these two neurotransmitters, which could induce a cardiorespiratory seizure. This failure has likely a multifactorial origin.

Heart Arrest↗
PubMed1990

Catecholamine release controlled by blood oxygen tension during deep hypoxia in trout: effect on red blood cell Na/H exchanger activity.

Changes in plasma catecholamine levels were measured in trout exposed to acute hypoxia, in order to correlate with acid-base disturbances due to activation of the cAMP-dependent Na+/H+ antiporters of red blood cells, as previously described (Fiévet B., Respir. Physiol. 74, 99-114, 1988). The extracellular acidosis corresponding with the stimulation of the exchangers, occurred when arterial oxygen partial pressure (PaO2) reached around 15 Torr (Thomas S., Respir. Physiol. 74, 77-90, 1988). This blood pH drop coincided with a marked increase in plasma catecholamine levels. The catecholamine secretion was transient and the hormones were cleared provided PaO2 remained above 10 Torr. On the other hand, when PaO2 remained below 10 Torr, there was a persistent secretion of catecholamines. This is in agreement with the fact that the exchangers are 'turned off' or sustained when PaO2 remains above or below 10 Torr respectively, as previously described. Following the transient hormone peak when PaO2 stabilized above 10 Torr, it was possible to trigger the second pattern of continuous catecholamine secretion by controlling water PO2 so that PaO2 declined below 10 Torr. We conclude that the blood oxygen level controls catecholamine secretion during deep hypoxia.

Acid-Base Imbalance↗
PubMed1990

Ammonia and monoamine concentrations in two brain areas in rats after one hyperoxic seizure.

Monoamines (catecholamines, serotonin, and metabolites) and ammonia were studied within two areas of the rat brain--the frontal cortex (FC) and the striatum (SA)--after exposure to hyperbaric oxygen (HBO) at 6 ATA up to the first seizure. An increase of norepinephrine (NE), dopamine (DA), and metabolites (HVA, DOPAC) measured by the HPLC/EC method were found in SA with a parallel increase of ammonia at variance with the FC where no monoamine changes, but a slight increase of ammonia, were found. Blood ammonia did not change with HBO. So, 20 min after one HBO seizure, there are regional differences in the brain, which are consistent with the previous findings of an SA start of electrocortical abnormalities at the onset of a seizure. Elevated DA, and possibly NE, levels may contribute to the accumulation of ammonia in the brain. During prolonged HBO exposure, this rise of ammonia could be one of the mechanisms involved in the relapse of seizures. It might also be implicated in initiation of the first seizure. By their situations and contents, SA glial cells could play an important role in brain HBO susceptibility.

Ammonia↗
PubMed1988

Effects of breathing an O2-H2 (20%-80%) mixture on the energy metabolism of the eel at 1 ATA.

The hypothesis of a specific effect of hydrogen on living organisms was investigated. Three tissues were studied: brain, muscle, and liver. Nucleotide concentrations (ATP, ADP, AMP, IMP, NAD) were determined using an HPLC method, and energy charge (EC) was calculated. These measurements were performed at atmospheric pressure for 50 or 132 h. Experiments were carried out using 15 control eels that breathed aerated water and 15 eels that breathed water saturated with oxygen (20%) and hydrogen (80%). No significant variation was found of the measured concentrations in muscle or liver, irrespective of the exposure duration to H2. In contrast, hydrogen induced in brain tissue a significant increase of AMP (p less than 0.005) and significant decreases of ATP (p less than 0.005) and EC (p less than 0.001). It should be noted that the EC decrease is already significant (p less than 0.05) after 50 h of exposure to H2. These modifications in energetic nucleotides were coupled with a small decrease of NAD (NS) in the three tissues explored. From the present results, obtained from eels at atmospheric pressure, it appeared that hydrogen could induce a perturbation of energy metabolism at the brain level. Its origin could be a partial saturation of respiratory chain carriers with exogen H2.

Adenosine Monophosphate↗
PubMed1988

Effects of hydrostatic pressure (HP = 101 ATA) on nucleotides and pyridine dinucleotides tissue contents in trout.

Tissue concentrations of energetic nucleotides and coenzymes, and oxygen consumption (MO2), have been measured in trout, exposed for 30 min in normoxic conditions (PwO2 congruent to 150 Torr), to 101 ATA (Atmosphere Absolute) of hydrostatic pressure (HP) and compared with results obtained at atmospheric pressure (1 ATA). The results show that in trout exposed to HP, there is an increase in MO2 accompanied by a decrease in ATP and energy charge (EC) in the three tissues explored (brain, liver, and muscle). Moreover, the fall of EC in muscle is accompanied by an increase in inosine 5' monophosphate (IMP). These results are in agreement with the hypothesis of an histotoxic hypoxia induced by HP, which can act at the Krebs cycle level and/or at the respiratory chain level, possibly by uncoupling the respiratory chain from oxidative phosphorylation processes.

Adenine Nucleotides↗
PubMed1987

Effects of hydrostatic pressure per se (101 ATA) on energetic processes in fish.

Nucleotides concentrations (ATP, ADP, AMP) have been measured in brain and muscle of eels exposed to 101 ATA of hydrostatic pressure (HP) for 3 hr. Survival times (ST) and oxygen arterial content (CaO2) have been measured in trouts exposed to HP = 101 ATA. The results show that at HP = 101 ATA, AMP increases (P less than 0.05) and ATP decreases (-12%; NS) in muscle but are not modified in brain; ST values are similar in normoxic and hyperoxic conditions, and CaO2 are similar at 1 ATA and 101 ATA of HP. It is concluded that HP tends to decrease aerobic production of energy. This phenomenon is not due to a failure in O2 transport from ambient medium to the cell but to a possible perturbation of the aerobic cellular processes leading to energy production (Krebs cycle and/or respiratory chain coupled to oxidative phosphorylation.

Adenine Nucleotides↗
PubMed1986

Brain and plasma biogenic amines analysis by the EC-HPLC technique: application to fish.

A HPLC technique has been developed for the analysis of biogenic amines (noradrenaline, NA; dopamine, DA; adrenaline, A; serotonin, 5-HT) in tissues and blood and then applied to fish. It appears that when compared to classical methods, HPLC is more rapid and reliable with a lower variation in the results. This technique showed that in eel blood, 5-HT and DA (and their metabolites) are missing or at least are present at very low concentrations.

Anguilla↗
PubMed1986

Catecholamine content (as measured by the HPLC method) in brain and blood plasma of the eel: effects of 101 ATA hydrostatic pressure.

The catecholamine content (noradrenaline, NA; adrenaline, A; dopamine, DA, and its metabolite, DOPAC) was measured, by the HPLC method, in brain and blood plasma of eels studied at atmospheric pressure (1 ATA) or at 101 ATA of hydrostatic pressure (HP). In the brain, HP induces a slight but significant increase (P less than 0.05) in A and DA contents but NA and DOPAC levels are not modified at 101 ATA when compared to 1 ATA. In the plasma, only A and NA are detected, adrenaline being the predominant amine. In eels exposed to 101 ATA HP, A and NA are strongly increased (+100%; P less than 0.01). The significance of the catecholamine increase in brain and plasma of the eels under HP is discussed.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

[Female hyperprolactinaemia. 19 cases (author's transl)].

The authors were able to confirm the ineffectiveness of vitamin B6. The correction of hyperprolactinaemia by bromocriptine restored ovarian function immediately, or after the failure of surgical treatment. It would still be premature to determine the exact place of surgery in this type of pathology.

Adolescent↗
PubMed1978

[Hypogonadotrophic hypogonadism. Pituitary and testicular reactivity--receptivity to androgens (author's transl)].

Six subjects aged between 19 and 29 years were studied. Gonadotrophins, follicular stimulating hormone or FSH and luteotrophic hormone or LH, were low in all cases. Under the influence of a single dose of 150 microgram of hypothalamic gonadotrophin liberation factor (LHRH), there was a preferential increase in FSH whilst levels of LH were little influenced. The continuous infusion of LHRH was associated with the same phenomenon. Only prolonged administration (for approximately 12 months) of chorionic gonadotrophins, resultes in a significant rise in plasma testosterone levels (low in all cases in the absence of stimulation). The level of urinary 3alpha-androstanediol represents a good parameter of androgenicity. Urinary 3beta-androstanediol is a metabolite of androgens formed in the liver. In hypogonadotrophic hypogonadism, and in particular in de Morsier's syndrome, the essential element would seem to be the absence of solicitation of the pituitary gonadotrophic cells by virtue of inadequate secretion of LHRH. The results of stimulation with chorionic gonadotrophins reflects the existence of inadequate maturation of testicular receptors to these hormones.

Follicle Stimulating Hormone↗