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Biomedical subjects

P Vert

Publications and source records attributed to P Vert.

At least 37 records · Page 2Linked to original sources
PubMed1995

[Handicaps and the perinatal period. II. Perinatal pathology and severe deficiencies].

BACKGROUND: In the last two decades, the infant mortality rate has dramatically declined. But improved management of newborns may induce an increased prevalence of neurodevelopmental handicaps. The aim of this paper is to estimate the rate of major disabilities and their relationships to perinatal events. POPULATION AND METHODS: Three hundred and sixteen children born in 1984 and registered by the "Commission Départementale de l'Education Spéciale" (CDES) were included in the study. Among these, 97 had either cerebral palsy, blindness, deafness, or mental retardation. These 97 children were compared to 602 school age controls using a multivariate analysis (logistic regression). RESULTS: The rate of major disabilities among the 6-year old children is 3.4/1000. It was 5/1000 in 1972 and 4.3/1000 in 1976. This frequency is higher in the children who were preterm (odds ratio--OR = 4.8), small for gestational age (OR = 3.3) or suffered from perinatal asphyxia (OR = 32.8). These three factors accounted for 37.4% of major disabilities. CONCLUSION: This study emphasizes the relationships between perinatal events and some major handicaps but also shows that antenatal factors may be involved in neurodevelopmental problems.

Asphyxia Neonatorum↗
PubMed1994

Neonatal necrotizing enterocolitis: a retrospective and multicentric review of 331 cases.

The authors retrospectively review 331 cases of necrotizing enterocolitis from 13 different departments of pediatric surgery; 184 cases were treated only medically at the acute stage (47 of whom developed intestinal stricture) and 147 cases were operated on at the acute stage. The different procedures of acute surgical intervention are reported and the results of two surgical procedures are compared. The first is a classical one comprising a laparotomy with exploration of the intestinal tract and resection of the necrotic segments followed by enterostomy above the resected area. The other procedure comprises a minimal laparotomy in the right lower quadrant with ileostomy above necrotic areas, without resection of necrotic segments associated with peritoneal drainage. The results are assessed using the postoperative mortality rate and the number of secondary intestinal strictures. Mortality during the first postoperative month occurred in 27.9% of cases, and intestinal strictures were noted in 31.3% of cases after acute surgical procedure.

Enterocolitis, Pseudomembranous↗
PubMed1994

Patent foramen ovale with left to right shunt in bronchopulmonary dysplasia: coincidental or associated complication?

Despite the use of exogenous surfactants, the incidence of bronchopulmonary dysplasia (BPD) has not decreased as much as expected. Of 208 newborns involved in trials with Exosurf at our center, 51 had BPD. Among these newborns, 8 were found retrospectively to have secondary worsening of respiratory distress syndrome after initial improvement with surfactant treatment. Oxygen requirements decreased from 89 +/- 15% to 58 +/- 16% (mean +/- SD), respectively, before and 48 h after surfactant, and then reached a plateau of 34 +/- 10% before dramatic deterioration at 22 +/- 9 days of life. The patients had signs of cardiac failure and increased oxygen requirements of up to 76 +/- 19% within 6 h. A patent foramen ovale (PFO) was demonstrated at echocardiography with a left to right shunt at Doppler. No other cause of worsening was found. Five infants had significant improvement when treated with digoxin and furosemide. This retrospective study raises questions about the relationship between PFO and BPD that should be explored in a prospective study.

Bronchopulmonary Dysplasia↗
PubMed1994

Effects of phenobarbital on cerebral blood flow during hypoxia.

Phenobarbital (PB), at anticonvulsant dosages, has been used in an attempt to reduce hypoxic brain injury in asphyxiated newborn infants. The effects of PB pretreatment on the cerebral blood flow (CBF) response in hypoxia were studied in 15 curarized and mechanically ventilated piglets: 7 animals were pretreated with 20 mg/kg of PB (group 1) and 8 served as untreated controls (group 2). Successive aliquots (25 ml) of carbon monoxide were introduced into a closed ventilator circuit and CBF (measured with radiolabelled microspheres), arterial blood pressure, blood gases, arterial pH and PaO2 were subsequently determined at different levels of hypoxia. The amount of hemoglobin available for oxygen transport (i.e. total Hb-HbCO) was used to express hypoxic aggression and decreased from grade I (> 2 mmol/l) to grade II (1-2 mmol/l) to grade III (< 1 mmol/l). In the control group, CBF increased during grade-I hypoxia and continuously remained above baseline values during grade-II and grade-III hypoxia. In pretreated animals, however, only grade-II hypoxia was associated with a significant increase in CBF above baseline. In addition during grade-III hypoxia, CBF decreased to the prehypoxic values despite a fall in cerebral oxygen delivery and cardiac index. These data suggest that PB should be used with caution to prevent brain damage in the asphyxiated newborn infants.

Animals↗
PubMed1993

Effects of bilirubin infusion on local cerebral glucose utilization in the immature rat.

The clinical features of kernicterus have been extensively described. However, there are still no data available on a possible correlation between the areas which appear to preferentially accumulate bilirubin and regional changes in cerebral functional activity. Therefore, we applied the quantitative autoradiographic [14C]2-deoxyglucose method to the measurement of local cerebral metabolic rates for glucose (LCMRglc) in immature rats receiving a bilirubin infusion. A loading dose of 160 mg/kg bilirubin in a buffered serum albumin solution was first given to the rats over 15 min. Thereafter, bilirubin was infused at a reduced rate, 64 mg/kg/h. Bilirubin infusion lasted from 2 to 3 h according to the age of the animal, in order to obtain a plasma concentration of bilirubin ranging from 200 to 300 mumol/l over the experimental period. Bilirubin entered the brain without any sign of blood-brain barrier alteration. The [14C]2-deoxyglucose was injected to the animals 45 min before the end of bilirubin infusion. Rats were studied at 3 postnatal ages, 10 (P10), 14 (P14) and 21 days (P21). Hyperbilirubinemia induced widespread decreases in LCMRglc's in all brain areas and at all ages. These decreases were mostly prominent in sensory areas, auditory and visual, as well as in hypothalamic and thalamic regions. Especially at P10, the distribution of LCMRglc's was strikingly heterogeneous in both cerebral cortex and caudate nucleus, appearing as alternate dark and white columns or as alternate dark and light dots, respectively. The data of the present study are in agreement with clinical observations reporting that bilirubin mostly accumulates in the striatum and cranial nerves and that the neurological sequelae of kernicterus are very often hearing loss as well as motor problems.

Albumins↗
PubMed1993

Effects of doxapram on carotid chemoreceptor activity in newborn kittens.

Doxapram is a respiratory stimulant which acts on peripheral chemoreceptors and central respiratory neurons in a dose-dependent fashion in the adult cat. In the newborn, the mechanisms of action of doxapram are still unclear. To evaluate the effects of doxapram on the carotid chemosensory discharge and its relationship with dopaminergic mechanisms in the carotid body, two groups of kittens less than 13 days old, anesthetized, artificially ventilated and paralyzed, were prepared for the recording of a single or a few chemosensory afferents of the carotid sinus nerve. The chemosensory activity was recorded under five conditions of inspired gas mixtures (21 and 8% O2 in N2, 100% O2, 5 and 10% CO2 in O2). Group 1 (n = 9) received only doxapram and group 2 (n = 8) was pretreated with haloperidol (1 mg/kg), a dopamine D2-receptor blocker, before receiving doxapram. Doxapram significantly stimulated the discharge rate of the carotid chemoafferents under all conditions of inspired gas. The chemosensory discharge was increased by haloperidol, and was raised further after doxapram by an amount similar to group 1. For instance, in normoxia, the activity increased from 2.9 +/- 0.4 to 7.5 +/- 0.9 impulse/s (mean +/- SEM, p < 0.01) in group 1 and from 3.8 +/- 0.6 to 9.1 +/- 1.0 impulse/s (p < 0.01) in group 2. These results indicate that the mechanisms of response of carotid chemoreceptor to doxapram are developed in the newborn kitten and doxapram acts independent of the dopaminergic mechanisms in the carotid body.

Animals↗
PubMed1993

Neonatal intensive care and birth weight-specific perinatal mortality in Michigan and Lorraine.

This study investigated the factors influencing use of neonatal intensive care and perinatal mortality in regions of the United States and France, two countries with similar health care systems but different approaches to health financing. The study employed birth certificates from Michigan and a birth registry from Lorraine in 1984. The study showed that geographic access and socioeconomic status were important in determining use of neonatal intensive care in both regions. Socioeconomic factors in perinatal mortality were also shown for both regions, after controlling for gestational age, birth weight, and neonatal intensive care use. In Michigan, infants of mothers with low education had higher mortality rates and in Lorraine residents of low income areas had higher mortality rates. A higher proportion of Michigan women delivered in hospitals with neonatal intensive care than in Lorraine, in all weight/gestation categories. Perinatal mortality rates were also lower in Michigan than in Lorraine, overall and within birth weight categories.

Birth Certificates↗
PubMed1992

An experimental model of generalized seizures for the measurement of local cerebral glucose utilization in the immature rat. I. Behavioral characterization and determination of lumped constant.

An experimental model of status epilepticus has been developed in the immature rat by administration of pentylenetetrazol (PTZ) using repetitive, timed intraperitoneal injections of subconvulsive doses. The pattern of behavioral signs has been well characterized in each age group, i.e. 10 (P10), 14 (P14), 17 (P17) and 21 postnatal days (P21). In this model, the dose of convulsant could be adjusted as a function of interindividual sensitivity and status epilepticus lated for quite a long duration to allow the measurement of local cerebral metabolic rates for glucose (LCMRglc) by means of the [14C]2-deoxyglucose method [J. Neurochem., 28 (1977) 897-916]. To estimate LCMRglc during status epilepticus, the lumped constant (LC) was re-calculated in controls and PTZ-treated rats. The control LC was 0.54 at P10 and 0.50-0.51 at the three older ages studied (P14, P17 and P21). During status epilepticus, it increased to 0.64 in P10 rats and decreased to 0.42 and 0.40, respectively, in P17 and P21 animals. At P14, LC was not affected by seizures. The measurements of brain lactate levels showed a large 4.5-10-fold increase in PTZ-treated rats as compared to controls at all ages. The results of the present study show that the immature brain responds to sustained seizure activity in a specific way according to its postnatal age. Moreover, our results underscore the necessity of re-calculation of LC to the quantification of LCMRglc in such pathological states, particularly in immature animals.

Aging↗
PubMed1992

An experimental model of generalized seizures for the measurement of local cerebral glucose utilization in the immature rat. II. Mapping of brain metabolism using the quantitative [14C]2-deoxyglucose technique.

The quantitative autoradiographic [14C]2-deoxyglucose technique (2DG) was applied to measure the effects of pentylenetetrazol (PTZ)-induced status epilepticus (SE) on local cerebral metabolic rates for glucose (LCMRglc) in 10 (P10)-, 14 (P14)-, 17 (P17)- and 21 (P21)-day-old rats. To produce long-lasting SE (55 min), the animals received repetitive, timed intraperitoneal injections of subconvulsive doses of PTZ until SE was reached. At P10 and P14, SE induced a marked increase in LCMRglc which affected 66 of the 76 structures studied. Increases were especially high (200-400%) in limbic and motor cortices at P10 and in some brainstem areas at these 2 ages. At P17 and P21, average brain glucose utilization was similar in seizing and control rats, but in PTZ-treated rats reflected a redistribution in local metabolic rates with increases in brainstem, midbrain, hypothalamus and septum, decreases in cortex, hippocampus, some sensory areas and white matter and no change in many motor and limbic structures. In a few cerebral regions, such as hippocampus, dentate gyrus and mammillary body, LCMRglc did not increase at P10 and P14 and decreased at P17 and P21 in PTZ- vs. saline-treated rats. The results of the present study show that the immature brain responds to sustained seizure activity in a specific way according to its maturational state. Moreover, these data allow the mapping of the vulnerability of cerebral structures to seizures, according to their metabolic response to convulsions.

Aging↗
PubMed1992

Acute hypoxia induces specific changes in local cerebral glucose utilization at different postnatal ages in the rat.

The quantitative autoradiographic 2-[14C]-deoxyglucose technique (2-DG) was applied to measure the effects of an acute hypoxic exposure on local cerebral metabolic rates for glucose (LCMRglcs) in the 10 (P10)-, 14 (P14)-, and 21 (P21)-day-old rat. The animals were exposed to hypoxic (7% O2/93% N2) or control gas mixture (21% O2/79% N2) for 20 min before the initiation and for the duration of the 2-DG procedure. Lumped constants were not affected by hypoxia at any age. At P10, the exposure to the hypoxic gas mixture induced a generalized increase in LCMRglc which affected 41 structures of the 45 studied. At P14, average cerebral glucose utilization was similar in hypoxic and control rats. LCMRglc increased in 5 areas and decreased in 11 regions, mainly brainstem and respiratory areas in hypoxic rats. Finally, at P21, LCMRglc decreased in 11 structures of hypoxic rats. The increase in LCMRglc in the hypoxic 10-day-old rat likely reflects stimulation of anaerobic glycolysis. Conversely, at P14 and P21, when the brain has become more dependent upon oxygen supply for its energy metabolism, levels of LCMRglc are similar in both groups of animals or decreased in a few structures of hypoxic compared to normoxic rats. The results of the present study show that the immature brain responds to an acute hypoxic insult in a specific way according to its maturational state. They are also in good accordance with the higher resistance of the immature animal to oxygen deprivation.

Acute Disease↗
PubMed1992

Carotid chemoreceptor response to natural stimuli in the newborn kitten.

The activities of carotid chemoreceptors at three levels of inspired PO2 (55, 145 and 690 Torr) and at two levels of inspired PCO2 (35 and 70 Torr in O2) were studied in 28 anesthetized, mechanically ventilated kittens aged 0-17 days. A biphasic response to hypoxia was found in 46% of them: the chemosensory activity increased to a peak within 30 sec after the initial response to hypoxia and thereafter declined slowly to a stable value. The steady-state single-fiber chemosensory activity at an inspired PO2 of 55 Torr was significantly lower in kittens less than 10 days old (mean +/- SE: 5.8 +/- 0.6 impulses.sec-1) than in the older ones (8.8 +/- 1.3 impulses.sec-1, P less than 0.03). The response curves to arterial PO2 were hyperbolic in both groups but the curve for the younger kittens was displaced to the left of the curve for the older ones. The response to hypercapnia was a progressive increase in chemosensory activity with little evidence of rapid or slow adaptation. The response to hypercapnia was significantly stronger in the older kittens than in the young ones. It is concluded that, in the kitten, the carotid chemoreceptor response to hypoxia may be biphasic. The responses to hypoxia and hypercapnia are already developed but are weak at birth and continue to develop further during the first weeks of postnatal life.

Animals↗
PubMed1992

Dual responses of carotid chemosensory afferents to dopamine in the newborn kitten.

The effects of dopamine and of dopamine D2 receptor blocker haloperidol on the activity of carotid chemoreceptors were studied in 24 anesthetized, paralyzed and artificially ventilated newborn kittens aged 0-17 days. Single or few fiber preparations of chemoreceptors were made from one carotid sinus nerve. The responses of the chemosensory afferents to intravenous injections of dopamine (5-50 micrograms.kg-1) were studied in kittens breathing air and 8% O2 in N2. The effects of haloperidol on the chemosensory activity in air or 100% O2 and on the chemosensory response to hypoxia were studied. Dopamine inhibited the chemosensory discharge in 25/44 studies in normoxia. Of the 9 studies performed in hypoxia, dopamine was excitatory in 5 or had no effect in 4 (P < 0.05 vs normoxia). Inhibition of the chemosensory discharge was observed in 24/37 studies performed in kittens aged more than 3 days and was predominantly excitatory in 6/7 studies in kittens aged 0-3 days (P < 0.01). One minute after haloperidol, the chemosensory discharge had increased significantly in all experiments. The biphasic pattern of chemosensory response to hypoxia (Marchal et al., Respir. Physiol. 87: 183-193, 1992) was not changed by haloperidol. The steady-state chemosensory activity was significantly increased after haloperidol, respectively from 3.9 +/- 0.7 impulses.sec-1 to 9.8 +/- 1.2 impulses.sec-1 in air, and from 13.1 +/- 1.4 impulses.sec-1 to 17.8 +/- 2.4 impulses.sec-1 in hypoxia (mean +/- SEM, P < 0.03). It is concluded that the dopaminergic mechanisms are active in the carotid body of the kitten, and the observed responses to dopamine and haloperidol are qualitatively similar to those reported in the adult cat.

Action Potentials↗
PubMed1992

Doxapram for the initial treatment of idiopathic apnea of prematurity.

The ventilatory effects of doxapram in the initial pharmacotherapy for apnea in the newborn were evaluated in 8 premature infants with idiopathic apnea. All received doxapram for 48 h at 0.25 mg/kg/h on the first day and 1 mg/kg/h on the second day. The ventilatory effects and the airway occlusion pressure (p0.1) were measured by means of a face mask, and a pneumotachograph. Compared to the pretreatment period, the mean of the frequency of central apnea greater than or equal to 15 s decreased significantly (p less than 0.01) by 48 and 75% during the first and second day, respectively. Both doses significantly increased inspiratory drive measured by airway occlusion pressure by 20% (p less than 0.05) and 32% (p less than 0.01) on the first and second day of drug treatment, respectively. Minute ventilation, tidal volume and mean respiratory flow significantly increased only with 1 mg/kg/h of doxapram, accompanied by a significant decrease in transcutaneous PCO2. No side effects were noted. Data suggested that doxapram alone at a dose of 1 mg/kg/h is effective for the treatment of neonatal apnea.

Apnea↗
PubMed1992

[Hemodynamic and renal adaptation of newborn infants of hypertensive mothers treated with acebutolol].

A prospective study of the hemodynamic and renal changes was undertaken in 11 neonates whose mothers were treated with acebutolol for hypertension during pregnancy, compared with a control group of 11 infants born to normotensive mothers. Monitoring of the cardio-respiratory system was performed for a period of 4 days. Renal function was studied during 2 periods (12-36, 60-84 hours of life). Hemodynamic failure was observed in 5 of 11 children from treated mothers. The data concerning the renal function of treated group showed: 1) a diuresis significantly lower during the first period (p less than 0.05); 2) the absence of significant rise in the glomerular filtration rates during the second period; 3) a lower sodium balance during the 1st and 2nd periods (p less than 0.02 and p less than 0.05), a lower calcium balance during the 1st period (p less than 0.01). No relationship was found between the renal changes and the hemodynamic disturbances. The direct effect of the drug on the glomerular and tubular functions and/or the renal arteriolar vasomotricity could explain these changes in the renal function in the newborns prenatally exposed to acebutolol.

Acebutolol↗
PubMed1991

Clonazepam in neonatal seizures: dose regimens and therapeutic efficacy.

The attempt has been made to define the optimal dose regimen of clonazepam in newborns suffering from neonatal convulsions. Results obtained from 22 patients (GA 28-41 weeks; PNA 4 h to 23 days) indicated that a dose of 0.1 mg/kg every 24 h was satisfactory in the majority of the patients. It is recommended as a starting regimen.

Asphyxia Neonatorum↗