[The problems of the child with food allergies. Health promotion activities].
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Adolescent↗
Biomedical subjects
L Barthélémy
Publications and source records attributed to L Barthélémy.
Pulmonary function in men after repeated sessions of oxygen breathing at 0.25 MPa for 90 min.
HYPOTHESIS: We wanted to evaluate the pulmonary effects of discontinuous oxygen breathing (15 min O2, 2 min air breaks, 15:2), at 0.25 MPa once a day for 90 min O2 (6 sequences) over 10 d. This sequence, which has never been evaluated, is currently used in our hyperbaric therapy center. METHODS: Clinical and functional pulmonary status (questionnaire, spirometry, flow/volume loop, pulmonary diffusing capacity for carbon monoxide) was assessed in 10 non-smoking healthy volunteers after one exposure at 0.25 MPa consisting of 90 min of discontinuous oxygen breathing (15:2) and in 10 non-smoking patients who received a hyperbaric treatment consisting of 90 min of the same discontinuous O2 breathing (15:2) once a day over 10 d. The patients received daily intravenous methylprednisolone (1 mg x kg(-1)) and nicergoline (60 mg). RESULTS: There were no respiratory symptoms in either group. As expected, for a single exposure of that duration, lung function did not change in volunteers; however, a significant decrease in maximal expiratory flows (MEF) at 50 (-15%) and 25% (-33%) of forced vital capacity (p < 0.05) without change in forced vital capacity (FVC) appeared in patients treated over 10 d. CONCLUSION: Repetition of the 15:2 oxygen breathing sequence for 90 min once a day over 10 d led to greater flow limitation in peripheral airways than reported after continuous oxygen breathing of 210 min at 0.3 MPa which showed a 7% decrement in MEF50 and a 12% decrement in MEF25. No studies reporting these indexes were found in the 0.2-0.25 MPa range. Similar decrements in MEF50 and MEF25 with steady FVC have been reported after 14 d of daily hyperbaric therapy (0.24 MPa) with 30:5 sequence (-9% and -13%, respectively), 80% of the patients were symptom free. Similarily, our patients were all symptom free and remained so 1 yr after the study, hence, this toxicity is of weak clinical significance in subjects free of inflammatory lung diseases. HBO therapy, though safe, is not totally without effect on the lung.
Adult↗
gamma-Aminobutyric acid concentrations in the cerebrospinal fluid of newborn infants determined by high performance liquid chromatography.
gamma-Aminobutyric acid (GABA), a major inhibitory amino acid, has a central role in cardiorespiratory regulation. Its measurement in the cerebrospinal fluid (CSF) complements the study of neurotransmission systems. Forty-one children were studied (postnatal age < 1 year). For each child, date of birth, date of sampling and current treatments were collated and their postnatal (days) and postconception (weeks) ages were calculated. CSF samples were studied using reverse phase high performance liquid chromatography (HPLC) with o-phthaldialdehyde derivation and spectro-fluorimetric measurement. A clear increase in levels of GABA was observed around 41 weeks postconception, followed by a progressive decrease, with levels stabilizing after 57 weeks postconception. GABA-regulated neuromodulation therefore appears to be mature at 41 weeks postconception and not at birth. The data could be used in further studies investigating amino acid metabolism in relation to brain function in various neurological disorders.
Age Factors↗
Amino acids and ammonia in the cerebral cortex, the corpus striatum and the brain stem of the mouse prior to the onset and after a seizure induced by hyperbaric oxygen.
The contents of amino acids (AA) and ammonia (NH3) were measured in corpus striatum, brain stem and cerebral cortex of two strains of mice exposed to hyperbaric oxygen (HBO). Mice of the HBO-sensitive strain (CD1) were exposed to 600 kPa O2 for 24 min versus 90 min for mice of the normal C57 strain, so that 50% of the mice in both strains developed a generalized convulsion. In the cortex of exposed but unconvulsed (EXUN) C57 mice, the contents of taurine, glutamine and NH3 increased while that of GABA decreased when compared to control mice. In the CD1 mice, NH3 content was increased while that of Asp decreased. After a convulsion, NH3 was increased in both strains, the AA contents returned to normal in C57 but Asp remained low in CD1 mice. Somewhat similar changes occurred in the striatum except that NH3 levels were less affected while GABA ones were significantly decreased in the CD1 mice exposed to HBO, whether convulsed or not. In the EXUN brain stem, Asp and Glu contents decreased. These decreases were greater in C57 on a percentage basis than in CD1 mice. GABA content was decreased in the C57 strain. After a convulsion, Asp and Glu levels remained low and NH3 accumulated in CD1 whereas in C57 only the Glu level was decreased. The cortical and striatal changes may indicate a lesser GABA supply in C57 strain and some Asp release in CD1 strain. In the brain stem of both strains, Asp and Glu release is possible in addition to GABA in C57 strain.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acids↗
Effects of a temperature increase on oxygen consumption of yellow freshwater eels exposed to high hydrostatic pressure.
Oxygen consumption was measured in yellow freshwater eels, Anguilla anguilla, during exposure to a hydrostatic pressure (HP) of 101 atmosphere absolute (ATA) for 3 h, either with or without a 5 degrees C increase in water temperature. It was found that concomitant increases in temperature and pressure resulted in an increase in oxygen consumption that was lower than when pressure alone was increased. When eels were acclimated to HP for 21 days and then submitted to a temperature increase of 5 degrees C, this induced a significant increase in oxygen consumption but only during the first hour. It is therefore concluded that raising the water temperature during the first hours under pressure could counterbalance the pressure effects on membrane fluidity in a thermodynamic manner and thus help shallow-water fish acclimate to high pressure. In contrast, when acclimation processes are ended, the temperature effect disappears within 1 h.
Acclimatization↗
[Normal values of respiratory function tests. Safety of normalized regression equations].
A frequent question in lung function testing is the extent of the margin of error in the measurements. Is the confidence interval (CI) of the usual summary equations for reference values larger than the sum of every possible error including interindividual variations and measurement errors which come from the apparatus, the technician and the patient? The analysis of the data of several authors including our data (lung function laboratory of Brest University hospital) leads to the conclusion that the summary equations of Quanjer et al. (1993) may be used safety as the CI is larger than the sum of all errors. However, this is only true if lung function testing is performed in optimal conditions, i.e. with frequently checked and carefully calibrated apparatus used by professional technicians in cooperating patients.
Adult↗
Effect of one hyperbaric oxygen-induced convulsion on cortical polyamine content in two strains of mice.
In rat striatum, after one hyperbaric oxygen (HBO)-induced convulsion, polyamine changes are found that could promote N-methyl-D-aspartate (NMDA) activation. In the HBO-sensitive CD1 mouse, unlike in the common C57 strain, there is some support for NMDA activation after the HBO seizure. We measured PA cortical content before and after the first HBO-induced convulsion (about 608 kPa O2) in CD1 and C57 strains. Putrescine, spermidine and spermine were dansyl derived and analysed by HPLC. Exposure to HBO significantly increased putrescine content only in CD1 though a similar trend was observed in C57. No further increase was observed after convulsion whatever the strain. There were no significant changes in spermidine or spermine to support NMDA activation. Therefore, putrescine increase in CD1 cortex could reflect the free radical formation that is known to be greater in CD1 than in C57 mouse. Attempts to increase putrescine levels before HBO exposure hastened HBO-induced convulsion, less than spermidine or spermine. Because of physiological polyamine interconversion, additional experiments with indirect manipulation of putrescine levels and study of their time-course would precise these preliminary reports on putrescine and HBO.
Animals↗
Effect of hyperbaric oxygen on prostaglandin and thromboxane synthesis in the cortex and the striatum of rat brain.
The effect of a previous exposure to hyperbaric oxygen (HBO) on the synthesis capacity of prostaglandin (PG) and thromboxane (TX) was investigated in the brain of male rats. Three groups of rats were used: 1. Neurotoxic HBO (n = 11): The rats were exposed to sixfold the atmospheric pressure (101.3 kPa), i.e., 6 absolute atmospheres (ATA), of pure O2 up to the first convulsion (6 ATA O2); 2. Mild hyperoxia (n = 10): The rats were exposed to compressed air at the same absolute pressure and for a similar time than that of the neurotoxic HBO group (here PO2 is 1.26 ATA); 3. Normoxia at atmospheric pressure (PO2 is 0.21 ATA) for control. There was no convulsion in groups 2 and 3. Decompression of the high pressure groups lasted 15 min. After decapitation, samples of the frontal cortex and the striatum were taken, weighed, washed, and then incubated in Krebs-Ringer bicarbonate for 1 h. The release of eicosanoids in the medium was determined by enzyme immunoassay. Mild hyperoxia only significantly reduced in the striatum the release of 6-keto-PGF1 alpha (1.3 +/- 2.4 vs 10.9 +/- 6.6 pg/mg wet tissue, p < 0.001; mean +/- SD) and PGE2 (3.2 +/- 2.7 vs 7.8 +/- 6.5 pg/mg wet tissue, p < 0.05), whereas TXB2 did not change.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Medical value of a respiratory mixture of oxygen and helium (Heliox)].
Lighter and more viscous than air, the oxygen-helium mixtures (heliox), well known to respiration physiologists, are used for functional exploration in the diagnosis of airways obstructions; they are also administered to deep-sea divers. However, it is usually little known that heliox can be used as therapeutic agent in the treatment of acute respiratory distress or severe disorders of ventilation caused by obstruction (e.g. inflammation). Heliox reduces the ventilatory work and increases alveolar ventilation, thereby improving haematosis and carbon dioxide elimination. The English-speaking authors, in particular, have a large experience of oxygen-helium mixtures in the treatment of such pathologies as severe asthma, small airways obstruction, cystic fibrosis, bronchoalveolitis, post-extubation pathologies, pharyngo-laryngeal oedema and drowning. The oxygen-helium mixture, therefore, participates efficiently, simply and inaggressively in the treatment of airway obstruction and acute respiratory distress.
Adult↗
[External resistances and dyspnea. Value of the study of flow-volume loops].
Breathlessness induced by external resistances (diaphragms with orifice size of 20, 15, 10, 7.5 and 5 mm) introduced in the ventilatory circuit of a spirometer and the corresponding parameters of a maximal flow-volume loop have been studied. 10 healthy subjects (5 men, 5 women), free from any acute or chronic cardiorespiratory disease, volunteered for this study. The results showed that the breathlessness (severe or moderate) was especially correlated with the decrease in peak flows, peak inspiratory flow (PIF) more than peak expiratory flow (PEF): when breathlessness was moderate, PIF was more decreased than PEF, -35% and -28% respectively; when breathlessness became severe, PIF also decreased more than PEF, -60% and -50% respectively; forced vital capacity (FVC) never changed and maximal expiratory flows at 50% and 25% of FVC were only slightly modified despite obvious breathlessness. The increase in diaphragmatic activity seemed more implicated than the activation of expiratory muscles in the genesis of breathlessness. PIF more than the commoner PEF could be a useful marker of the breathlessness perceived by the patient during acute bronchial obstruction (asthma).
Adult↗
A simple device for measuring a vertical jump: description and results.
A simple and cheap device has been designed which makes it possible to quantify a vertical jump. The parameters which can be measured or calculated with this device include: height of the jump, duration of thrust, maximal velocity and thus the corresponding maximal power output. The device was tested on 22 young soccer players for whom the height of the jump (0.47 m, SEM 0.015) and maximal power output (34.9 W. kg-1, SEM 1.04) were considered. The device is proposed for assessing training methods and sports aptitude.
Adolescent↗
Ventilatory responses to hypoxia in healthy subjects: a comparison between young children and adults.
Ventilatory responses and breathing patterns during acute hypoxia have been studied at sea level in healthy subjects (8 children, 8 adults). While breathing ambient air it appears that, compared to adults, children hyperventilate when ventilation is standardized to body mass unit. During hypoxia, ventilatory strategy differs with age: when adults essentially increase tidal volume (VT), children increase VT and ventilatory frequency (fr). The ventilatory steady-state response to hypoxia is lesser in children than in adults, that is to say, children have a lower O2 ventilatory sensitivity. These results, which show that adults and children have qualitatively and quantitatively different ventilatory responses to hypoxia, are interpreted in terms of the ability to displace gaseous volumes.
Adult↗
Effects of maximal breath holding on maximal expiratory flows.
Effects of breath holdings (BH) on bronchomotor tone, maintained until their breaking points, have been studied using maximal expiratory flow volume curves (MEFVC). BHs have been performed either at high lung volume (total lung capacity, EIBH) or at low lung volume (residual volume +250 ml, EEBH), an inspiratory manoeuvre immediately preceding the MEFVC. The results show that: (1) EIBH induces a significant increase of expiratory flow at 25% of FVC; (2) EEBH induces a significant and constant decrease of expiratory flows at 50% and 25% of FVC. The same modifications were recorded after inhalation of 400 micrograms of Fenoterol or 80 micrograms of Ipratropium bromide. The observed results are suggestive of mechanical effects of BH on expiratory flows. After EIBH airway hysteresis dominates over lung hysteresis, with opposite effects after EEBH.
Administration, Inhalation↗
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↗
[Changes in the respiratory function in Gougerot-Sjögren syndrome].
Tests for lung function assessment were performed in 36 subjects (34 women, 2 men; mean age 56 +/- 2.2 years) presenting with Sjögren's syndrome of 8.4 +/- 1.0 years duration. The tests used in the study were: spirography with measurement of residual volume, flow volume curve, total dynamic resistances, diffusing capacity of the lung (steady state and breath hold methods), estimation of alveolar ventilation and, in some subjects, dynamic lung compliance. Sjögren's syndrome was assessed by anatomo pathological methods and divided into primary (n = 9) and secondary (n = 27). Secondary Sjögren's syndrome (SGS II) was associated mainly with a connective tissue disease (rheumatoid arthritis in 23 cases). The results of lung function tests showed distal airway obstruction associated with a decrease in lung diffusing capacity due to functional disturbance of the alveolar capillary membrane. Moreover, the greater alteration of lung function observed in SGS II could be explained by: a direct correlation between duration of SGS and alteration of lung function, and an alteration of the parietal ventilatory mechanics, at least in subjects with rheumatoid arthritis.
Arthritis, Rheumatoid↗
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↗
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↗
Study on mammal (rat) of the neuro-muscular synapse function under hyperbaric conditions (11 ata): effects of the curarization.
Under hyperbaric conditions (11 ata) obtained with normoxic O2-N2 mixtures spontaneous EMG activity disappears, as do reactions to noise, but this phenomenon is reversible after the substitution of Helium for Nitrogen in the mixture. Analysis of EMG responses to sciatic nerve excitation has revealed no difference between the EMG tracings recorded under normobaric pressure and those obtained under hyperbaric conditions (O2-N2 or O2-He, 11 ata), and hyperbaric conditions do not seem to interfere with neuro-muscular synaptic transmission. Furthermore, the effect of Pavulon (an antidepolarising, acetyl-cholino-competitive curare-mimetic drug) is similar under normal and hyperbaric conditions: hyperbaria change neither the onset of neuro-muscular blockage nor its intensity or duration. The absence of a specific effect on synapse function of a change in the diluting gas from nitrogen to helium suggests that there was no change in post-synaptic receptor function. This result is not in accordance with the hypothesis that inert gas pressures of less than 10 ata modify molecular structures particularly at the neuro-muscular synapse level.
Animals↗