Biomedical subjects
Publications and source records attributed to F Marchal.
The physiologic factors that predispose premature infants to apnea are reviewed in this article. Management and treatment of "idiopathic apnea" are discussed. "Symptomatic apnea" should be treated according to its primary cause.
Ventilatory and waking responses to laryngeal stimulation were studied in six chronically tracheostomized lambs breathing through an endotracheal tube. A balloon catheter inserted in the rostral tracheal segment allowed application of distilled water onto the larynx. Apnea, the main primary ventilatory response, was shorter in wakefulness (7.9 sec) than in quiet (10.7 sec) or active sleep (10.6 sec, residual variance = 3.29), where the response to laryngeal stimulation was poorly reproducible. Arousal delay measured from the neck muscle EMG was longer in active (21.1 sec) than in quiet sleep (5.4 sec, residual variance = 9.05). Arousal preceded apnea termination more often in quiet than in active sleep. When breathing resumed a sigh frequently occurred following prolonged apneas. We conclude that laryngeal stimulation elicits apnea in all states in mature lambs. The termination of apnea is related to waking up in quiet but not in active sleep, where arousal is depressed. A comparison of our results with data from preterm and adult mammals strongly suggests that the ventilatory response to laryngeal stimulation during active sleep is unaffected by maturation.
The authors report their experience in the treatment of advanced scirrhous carcinoma of the breast with estrogens only at the Curie Institute. Patients were elderly women in whom other forms of treatment were contraindicated because of local tumor extension or a poor general condition related to age. 32.5% of the patients responded favorably (out of a total of 40 patients). Mean duration of treatment was 21.5 months. Dosage varied according to efficacy and side-effects. Both dienestrol and diethylstilbestrol were used with no preference for one or the other. Serious side-effects were relatively infrequent and minor side-effects either resolved or improved significantly when dosage was reduced or treatment discontinued. Considering the present widespread use of antiestrogens and the systematic detection and dosage of intratumoral hormone receptors, the authors stress the advantages of this seemingly paradoxical effect of estrogens and underline the need for comparative studies.
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The laryngeal chemoreflex was studied during quiet and REM sleep and wakefulness in premature newborn lambs. The response to reflex stimulation with a 5 sec-water infusion was evaluated during 30 sec, as % change in ventilation, heart rate and blood pressure. Apnea, hypertension and bradycardia were more pronounced during sleep than during wakefulness, when arousal was not associated with the stimulation. The response was similar during quiet and REM sleep. Arousal, which occurred in 24 and 31% of the tests respectively, resulted in a response comparable to that seen during wakefulness. The respiratory drive was evaluated by measurement of the mean inspiratory flow and was found to be decreased during both sleep states when compared to wakefulness. We propose that during sleep in the newborn period there is a decreased ability to respond to asphyxia possibly due to a functional immaturity of the arterial chemoreceptors. This results in a low incidence of arousal and a delayed termination of the pronounced poststimulus apnea resulting from laryngeal chemoreflex stimulation.
The cardiovascular response to administration of water to the larynx was studied in unanesthetized newborn lambs. The cardiovascular components of this laryngeal reflex response consisted of a decrease in heart rate associated with a decrease in cardiac output, an increase in systemic and pulmonary vascular resistance associated with increased blood pressure and blood flow redistribution. Blood flow decreased in carcass, kidneys, intestines, liver and spleen and increased in head, brain and heart. The magnitude of the separate components of the cardiovascular response correlated significantly with each other and with the respiratory response. Alpha-adrenergic blockade eliminated the blood pressure and blood flow redistribution response. Atropine blocked the heart rate response. The reflex-elicited decrease in cardiac output and the increase in systemic vascular resistance were augmented by beta-adrenergic blockade. The cardiovascular responses were diminished, but not abolished, when oxygenation and rhythmic ventilation were artificially maintained during laryngeal water stimulation. These results indicate the possible interaction with the arterial chemoreceptors, stimulated by the concomitant 26 torr decrease in arterial oxygen tension, as well as with the cessation of the pulmonary inflation reflex associated with the apnoea.
In general, there is little agreement how digoxin should be used in newborn, and the results of studies in this field seem contradictory. This study attempts a quantitative assessment of the number and the sensitivity of cellular receptors for digoxin in the organism, by the in vitro measurement of erythrocyte 86Rubidium uptake in neonates compared with adults and old people. Red blood cells are first incubated with differing concentrations of digoxin, and then incubated with 86Rb. The initial level of 86Rb uptake (Rbi) is that observed in the absence of digoxin. The 50% index of captation (IC50) is the digoxin concentration in nanograms per ml at which 86Rb uptake is half Rbi. Three groups of patients were studied: Group I: 12 neonates, less than 5 days old; Group II: 11 adults (26 to 57 years old); Group III: 9 elderly people (71 to 82 years old). Rbi was significantly lower in neonates (Mean +/- SD: 25.8% +/- 3.5, P less than 0.001) and in the elderly (29.9% +/- 3.1) than in adults (36.8% +/- 4.6). IC50 was significantly lower in the elderly (12.1 ng/ml +/- 2.4) than in the adult patients (20.5 ng/ml +/- 5.5, P less than 0.001). In the newborns, values of IC50 were widely scattered (16.2 ng/ml +/- 7.2). The authors suggest that since Rbi reflects Na+, K+-ATPase activity, this activity is diminished in newborn and old people, and indicates that they have fewer cellular receptors for digoxin than adults. In the elderly, the low IC50 would imply increased sensitivity to digoxin. In neonates, the wide range of values for IC50 suggests considerable individual variation in sensitivity to digoxin. The results are consistent with the recently recommended lower dosages of digoxin in neonates.
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Indomethacin (I) pharmacokinetics was evaluated in 6 premature infants who received the drug for treatment of patent ductus arteriosus. Administered by oral or rectal route, I (0.2 mg/kg/24 h X 3) was promptly absorbed with peak plasma concentrations attained within 1 and 3 h. The elimination of I appeared to follow two compartment open model kinetics, with terminal plasma half-lives ranging from 30 to 90 h. Apparent plasma clearance values were between 0.076 and 0.335 ml/min/kg. Ductal closure was observed in 4 of the 6 infants. Data point to a possible relationship between therapeutic effects and I plasma concentrations.
The neonatal pulmonary hypertension occuring with fetal distress can be evaluated by the echographic study of the sigmoide pulmonary valves. This non-invasive method can appreciate the severity of the hemodynamics disturbances and their evolution. In this preliminary study the authors report their experience through 14 cases.
A 42-year-old woman, who had been taking oral contraceptives for 10 years, developed a primary carcinoma of the liver. The diagnosis was made by biopsy under laparoscopic control. Twenty one cases have already been reported in the literature. The aetiological role of contraceptives in the development of generally benign (approximately 200 published cases) and sometime malignant hepatic lesions, has not been definitely proven. The regression of certain benign tumours when contraceptives are stopped is the essential argument. In some patients, the association of benign lesions and of hepatic carcinoma suggests a single pathogenesis. The early recognition of such lesions justifies their being sought routinely in patients taking oral contraceptives (palpation of the liver, questioning concerning pain in the hepatic region). A national register will be required in order to determine their exact prevalence.
A new case report of primary malignant hepatic tumor during a long term oral contraception is presented. A direct role of contraceptives drugs cannot be claimed because of little cases reported. Nevertheless, appearance of carcinogenic compounds in predisposed women may be evoked.
The objective of this study was to evaluate the consequences of facioscapulohumeral muscular dystrophy (FSH MD) using two different but complementary procedures: an analysis based on the three different dimensions of disablement developed by the WHO--impairment, disability, and handicap--and a study of the psychological repercussions on social identity. Sixty-eight individuals with FSH MD, with 68 members of a control group, responded to a battery of psychosocial questions. Individuals with muscular dystrophy were also studied with reference to the dimensions of impairment, disability and handicap. The results showed that there are close correlations among measures of the three dimensions of disablement. Evaluations made by people with muscular dystrophy of the seriousness of their own disablement are strongly linked to objective measures of impairment. Furthermore, we found that having muscular dystrophy does have certain consequences for an individual's self-identity, although the degree to which one's self-image is validated is to some extent independent of the seriousness of the illness.
The lack of interest about oculorespiratory reflex (ORR) in surgery and experimental studies is obvious. However the authors insist on the importance of its clinical traduction. The purpose of this study is to determinate an experimental model with titration of stimulus (pressure or traction) and therapeutic test. Our first Results prove the clinic entity of O.R.R. In first conclusion, we can insist on the importance of ventilatory assistance during squint surgery and on the monitoring of PE CO2 and Sa O2.
Sudden infant death syndrome (SIDS) claims one in five hundred babies between 1 and 12 months of life. Since no cause of death is found at autopsy, SIDS has been and often remains a complete enigma for pediatricians, physiologists and forensic pathologists. However, there is growing evidence from careful epidemiologic, pathologic and physiologic studies that subtle changes occur in those babies for a variable period of time before death. Some of these data are reviewed and interpreted in the light of the sleep apnea-hypoventilation inducing chronic hypoxemia hypothesis. It appears that no single factor is characteristic of, or responsible for, SIDS; rather, a combination of different adverse circumstances occurring during a period of increased vulnerability may cause the fatal outcome in some infants. Some preventive aspects of SIDS in low birth weight babies, siblings of SIDS victims and near-miss SIDS are discussed.
The pharmacokinetic and pharmacodynamic effects of indomethacin were studied in 18 prematures with patent ductus arteriosus, treated either enterally (group I, n = 7), or intravenously (group II, n = 11). A definitive closure assessed by echocardiography was observed in 13 cases (72%), and it was only transient in 4 cases (21%). Assisted ventilation was discontinued between 1 and 6 days following therapy in 14 cases. In most cases, indomethacin induced a significant reduction of diuresis but the plasma creatinine level increased above 15 mg/l in 3 cases only. The elimination half life of indomethacin (t 1/2 beta), of 40.3 +/- 12.2 hours in group I and 33.9 +/- 11.7 hours in group II, is increased as compared with adults. The difference of the surface under the curve (AUC O leads to 24 h, ng.ml-1.h-1) between the infants who presented complete or transient closure, suggests a relationship between the biodisponibility of the drug and the effect on patent ductus arteriosus. Treatment with indomethacin is an interesting alternative to surgical ligation in prematures with patent ductus arteriosus. Because of its side effects, especially on the kidneys, it is recommended to use this treatment only in intensive care units. The intravenous route seems to be better than the enteral route.