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Biomedical subjects

M Chaussain

Publications and source records attributed to M Chaussain.

At least 37 records · Page 2Linked to original sources

[Use of a fermented powdered milk in malnourished or lactose intolerant children].

Lactase deficient subjects, who form the bulk of the world population, absorb yogurt lactose because the bacteria used for fermentation produce beta-galactosidase. From a milk fermented by these bacteria and dried by a temperature-controlled process a power could be obtained which possess residual lactase activity but, unlike yogurt, does not need storage at low temperature. The lactose of this fermented powdered milk is perfectly absorbed, as proved by hydrogen respiratory tests performed in 35 lactose intolerant African subjects living in isolated villages. In 25 malnourished children under 3 years of age, this milk allowed renutrition without inducing diarrhoea--a result which could not have been obtained with ordinary milk in two-thirds of the cases. This type of food is potentially valuable to feed the large population of the third world.

Adolescent↗

Feeding lactose-intolerant children with a powdered fermented milk.

Fresh yogurt has been proposed as a milk substitute for lactase-deficient patients. We investigated the possibility that a dried, low-fat milk fermented by yogurt microorganisms would be effective. Processing of a fermented milk by spray-drying led to a powder with persistence of lactase activity (11.7 units/g) without storage at 4 degrees C and stable at room temperature (20-23 degrees C). The tolerance and absorption of 10.5 g of lactose in a volume of 150 ml was studied in 25 Gabonese lactase-deficient children aged 5-14 years in the form of a standard humanized milk formula followed 1 week later by the powdered fermented milk formula. Results of the breath hydrogen test showed that in 24 of 25 cases, lactose absorption was normal with a maximal rise of hydrogen over baseline of under 13 ppm after ingestion of the powdered fermented milk. The rise was above 20 ppm in the 25 children with the same load of lactose in the form of the standard formula and one-third had symptoms of lactose intolerance. This powdered fermented milk preparation should be considered as a valid approach in programs of nutritional support targeted to countries with a high prevalence of lactase deficiency.

Adolescent↗

[Intestinal parasites and lactose malabsorption].

Breath-test was performed for diagnosis of lactose malabsorption in 50 Gabonese children of normal nutritional status, aged 5 to 15 years, with parasites in stools, but without diarrhoea or digestive symptoms. Control group was unparasitized and consisted of 17 children and 18 young adults living in the same area. Parasites discovered by stool examination were Ascaris lumbricoides in 76% of parasitized children, Trichuris trichiura in 58%, Giardia in 24%, Entamoeba histolytica in 20%, Schistosoma intercalatum in 16% and Necator Americanus in 14%. Children were given a 10 g lactose load and adults 20 g. Lactose malabsorption was discovered in 64% of parasitized patients and in 63% of unparasitized. Ten of 12 (83.3%) of Giardia infected children had a lactose malabsorption (no significant difference). These data show that decrease of lactase activity in African children is not related to the presence or to the importance of intestinal parasitism, except for Giardia infestation, if nutritional status is normal.

Adolescent↗

Serum thymic hormone thymulin activity is normal in children with asthma.

In asthma, it has been hypothesized that suppressor T-lymphocytes play a protective role and have been reported to be functionally abnormal. Thymic hormone thymulin plays a role in the differentiation of T-lymphocytes and plasmatic thymulin concentration and is related to the functional state of the thymus. To assess the participation of the thymus in the impairment of T-lymphocyte function, we measured plasma thymulin activity in children with allergic asthma (N = 40). The plasma thymulin activity was compared with plasma thymulin activity of children with nonallergic asthma (N = 6), children with atopic dermatitis (N = 9) or allergic rhinitis (N = 7), and in age-matched healthy control children (N = 18) (age range of children studied, 2 to 19 years). Thymulin activity was found within the normal range (1/16 to 1/64) in all control children and in all children with allergic asthma and allergic rhinitis, as well as in all children with intrinsic asthma and atopic dermatitis. Our findings are at variance with the low thymulin activity previously reported in allergic asthma, and we could not explain these discrepancies. (Both studies used the same bioassay, and the population studied did not appear to be different.) T-lymphocyte abnormalities in subjects with asthma must be assessed by other means than measurement of thymic function.

Adolescent↗

Milk lactose malabsorption in Gabon measured by the breath hydrogen test.

It is usual to consider that the greatest part of the black African population is lactose intolerant. Also, milk lactose malabsorption was studied by a breath hydrogen technique in 87 Gabonese children and 20 Gabonese adults (central Africa). The prevalence of malabsorption was 64.2% in rural schoolchildren, 65% in the urban hospitalized, and 60% in adults. Twelve children and six adults had clinical symptoms after a lactose load. All subjects were Bantus, with no tradition of consuming dairy products. These data must be considered in programs of nutritional support in Africa.

Adolescent↗

Pretreatment with an inhaled alpha 1-adrenergic agonist, methoxamine, reduces exercise-induced asthma.

In order to assess the role of the bronchial circulation in the pathogenesis of exercise-induced asthma (EIA), we conducted a double-blind, randomized study of the effects of pretreatment with an inhaled alpha 1-adrenergic agonist, methoxamine (Mx), in nine asthmatic teenagers with known EIA. Exercise consisted of 5 min cycle ergometry at a submaximal, constant work-load, while the subjects breathed dry air at ambient temperature. Forced expiratory volume in one second (FEV1) was measured at baseline, 15 min after pretreatment of either Mx or saline, and serially after exercise. Mx significantly reduced the exercise-induced fall of FEV1 without modifying baseline FEV1 in five of the eight subjects, had little or no effect in three and caused an acute asthmatic attack in the remaining subject. Mx has potent constrictor effects on both bronchial and vascular smooth muscles through stimulation of postjunctional alpha 1-adrenoceptors. Therefore, the protective effect of Mx on EIA may be attributed to vasoconstriction of tracheobronchial vessels opposing the hyperaemia and mucosal airway oedema that may cause, at least in part, the exercise-induced acute bronchial obstruction in EIA. Alternatively, Mx stimulates mucus, water and electrolyte secretion by airway epithelium and may, therefore, oppose the dehydration of airway surface that could be a causative factor of EIA.

Administration, Inhalation↗

Respiratory effects of nitrous oxide during halothane or enflurane anaesthesia in children.

The respiratory effects of nitrous oxide (N2O) were studied during halothane and enflurane anaesthesia in 12 children (mean age 46.4 +/- 29.3 months, mean weight 15.3 +/- 4.2 kg) during surgery under continuous extradural anaesthesia. Four equipotent anaesthetic states were studied in random order: 1) halothane 1 MAC in oxygen, 2) halothane 0.5 MAC + 50% N2O, 3) enflurane 1 MAC in oxygen, 4) enflurane 0.5 MAC +50% N2O. End-tidal fractions of CO2 (PetCO2) and halothane and enflurane were measured using infrared analysers. The respiratory variables (tidal volume VT, minute ventilation VE, respiratory frequency F, inspiratory time Ti, mean inspiratory flow VI, effective inspiratory time Ti/Ttot) were measured using a pneumotachograph. Significant changes were observed between the four states for VE, VI, F and PetCO2, whereas the values of VT, Ti and Ti/Tot did not differ significantly. The respiratory depressant effect of 1 MAC of either halothane alone or of the mixture of halothane and N2O was very similar. During enflurane anaesthesia, PetCO2 was less increased when N2O was substituted for enflurane, owing to a significant increase in respiratory frequency. A marked decrease in VE together with an increase in PetCO2 was observed during enflurane anaesthesia (states 3 and 4) when compared to the corresponding states during halothane anaesthesia (states 1 and 2). The respiratory depressant effect of enflurane is greater than that of halothane in unpremedicated children, even when substituting N2O for an equal MAC fraction of enflurane.2+ The effect of N2O on respiratory patterns seems to depend on the inhalational agent used and/or on the vesting respiratory frequency.

Anesthesia, Inhalation↗

The respiratory effects of isoflurane, enflurane and halothane in spontaneously breathing children.

The respiratory effects of halothane, isoflurane and enflurane were assessed during nitrous oxide anaesthesia (N2O 50%) in three groups of unstimulated, spontaneously breathing children who weighed 10-20 kg and were aged 1-6 years. Respiratory variables were measured or calculated from capnographic and pneumotachographic recordings at three multiples of minimal alveolar concentration (MAC). The slope of the carbon dioxide response was measured. Similar increases in end tidal carbon dioxide were found for the three agents at each MAC multiple, and similar decreases in tidal volume and in the slope of the ventilatory response to carbon dioxide. A dose-related tachypnoea occurred with halothane and a significant decrease in the duration of inspiration and the duration of each breath at the deepest level of anaesthesia. A significant increase in both these times occurred with enflurane, and a decrease in respiratory rate. No change in respiratory rate occurred with isoflurane at increasing alveolar concentrations whereas at each level of anaesthesia inspiratory time was significantly reduced.

Anesthesia, Inhalation↗

Ventilatory changes during nitrous oxide isoflurane anaesthesia in children.

The changes in ventilatory variables under nitrous oxide isoflurane anaesthesia were studied in 10 children (mean age 46 +/- 13.4 months, mean weight 16.2 +/- 2.1 kg). Measurements of flow and volume were performed by pneumotachography. PE'CO2 was measured by capnography. The following variables (VE, VT, TI/TTOT, VI, PE'CO2) were measured or calculated under three increasing inspired isoflurane concentrations (0.75%, 1.5%, 2.25%). At each level of anaesthesia, ventilatory changes during exposure to an inspired CO2 fraction of 2% were studied. The increase in the inspired concentration of isoflurane was associated with a decrease in alveolar ventilation. PE'CO2 increased significantly with increasing depth of anaesthesia. The respiratory rate was slightly increased under light nitrous oxide isoflurane anaesthesia, but no further changes were observed with increasing depth of anaesthesia, although the children were breathing a mixture of nitrous oxide and oxygen. The ventilatory response to a raised inspired CO2 is markedly decreased under light nitrous oxide isoflurane anaesthesia, and decreases significantly with increasing depth of anaesthesia. In response to a raised CO2, VE, VT and VI increase, but respiratory rate decreases or remains constant and TI/TTOT is unchanged.

Anesthesia↗

Influence of breathing pattern on functional residual capacity in sleeping newborn infants.

The present study was designed to assess the influence of breathing pattern on the variations of functional residual capacity during sleep in newborn infants. Functional residual capacity was measured by the He-dilution method. Neurophysiologic criteria were used to identify sleep states. Movements of chest and abdomen were monitored. Twenty-six healthy newborn infants were studied. Sixteen were premature and 10 were at term. Functional residual capacity did not change in relation to changes in sleep states. In active sleep it was 1.48 +/- 0.07 ml/cm compared with 1.50 +/- 0.06 ml/cm in quiet sleep. Functional residual capacity decreased when rib cage and abdomen moved out-of-phase with a value of 1.38 +/- 0.09 ml/cm as compared to 1.56 +/- 0.09 ml/cm when in phase (P less than 0.01), in the 7 infants who displayed these two opposite patterns.

Functional Residual Capacity↗

Ventilatory responses to carbon dioxide in children during nitrous oxide-halothane anaesthesia.

The ventilatory response to carbon dioxide was studied in 12 unpremedicated children, aged 20-68 months, weighing between 10 and 20 kg, under nitrous oxide-halothane anaesthesia. Tidal volume (VT) and end-tidal carbon dioxide tension (PE'CO2) were continuously measured by pneumotachograph and capnograph. Minute ventilation (VE), respiratory rate (f), mean inspiratory flow (Vl) and effective inspiratory cycle (Tl/Ttot) were calculated during anaesthesia at three different inspired halothane concentrations (0.5, 1 and 1.5%). The ventilatory response to carbon dioxide was determined by relating the increase in ventilation during exposure to 2% carbon dioxide to the change in end-tidal carbon dioxide concentration. When the inspired concentration of halothane increased, there were significant decreases in VE, VT, Vl, and a significant increase in PE' CO2. The slope of the carbon dioxide response under light nitrous oxide-halothane anaesthesia (0.5% halothane) was relatively flat (18.64 ml min-1 kg-1 mm Hg-1) when compared with the mean values published for anaesthetized adults, children or neonates. When the inspired concentration of halothane was increased, the slope decreased significantly (39% of initial value at 1% inspired halothane, 26% at 1.5%). The addition of carbon dioxide produced significant increases in VE, VT and Vl but no change in respiratory rate. No statistical difference was observed in the slope of carbon dioxide response between the initial and "control" periods which were measured at the same inspired halothane concentration (0.5%).

Anesthesia, Inhalation↗

Paradox of REM sleep.

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Functional Residual Capacity↗

Functional residual capacity and sleep states in the premature newborn.

Functional residual capacity (FRC) variations in relation to sleep state changes were studied in 11 premature infants with birth weights of 1.68 +/- 0.48 kg and gestational ages of 32.7 +/- 2.2 weeks (mean +/- SD). Helium dilution was used to measure FRC, and sleep states were identified using neurophysiologic criteria. No significant difference in FRC could be demonstrated between data collected during active sleep (AS) and quiet sleep. However a relationship was shown between AS and paradoxical breathing (p less than 0.02) and between AS and irregular breathing (p less than 0.05). Several factors are discussed which might explain the discrepancy between the present data in premature infants and the previously published data in term infants. (1) Neurophysiologic identification of sleep states does not include breathing pattern whereas behavioral identification does. It is therefore possible that lung volume changes are related to breathing pattern changes and not to sleep state changes per se. (2) Maturational changes may occur among the mechanisms which control FRC, leading to a progressive stabilisation of FRC, the variation of which could become related to sleep state changes.

Functional Residual Capacity↗

[Mass spectrum analysis of expired and alveolar gas during separate bronchospirometry].

It is possible to measure with a mass spectrometer the oxygen and carbon dioxide pressure in expired gas and alveolar gas in each lungs during a separate bronchospirometry. In 15 cases out of 26 (of which 21 had broncho-pulmonary cancers) it was possible to trace serious disorders of the alveolar-capillary exchanges in the diseased lung, probably related to an altered ventilation-perfusion relationship. This technique brings more data to the physio-pathologist than the plain measurement of the oxygen consumption of the diseased lung.

Bronchial Neoplasms↗