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Biomedical subjects

L Paunier

Publications and source records attributed to L Paunier.

At least 19 recordsLinked to original sources
PubMed1992

Serum and intracellular magnesium during normal pregnancy and in patients with pre-eclampsia.

OBJECTIVE: To determine the serum and lymphocyte magnesium concentrations during normal pregnancy and to compare the magnesium status in the third trimester of pregnancy between women with normal pregnancy and those with gestational hypertension (GH) or pre-eclampsia (PE). DESIGN: A prospective cross-sectional study followed by a prospective comparative study. SETTING: Department of Obstetrics and Gynecology, Department of Pediatrics and Genetics, Hôpital Cantonal Universitaire Genève, Switzerland. SUBJECTS: Seventy-one healthy pregnant women, with normal pregnancies between 6 and 38 weeks gestation. The second part included 43 women in the third trimester of pregnancy, 11 had GH, 11 had PE and 21 formed the comparison group of healthy normotensive women. MAIN OUTCOME MEASURES: Total serum and intralymphocytic Mg concentrations and urinary Mg excretion. RESULTS: There was a progressive reduction in total serum magnesium concentrations during normal pregnancy, thought to be partly due to haemodilution, because the decline in concentration of serum proteins paralleled that of Mg (P less than 0.001). In the three groups studied in the third trimester the serum Mg concentration was very similar in the GH and the comparison groups, but it was significantly higher in the PE group (P less than 0.01). The intralymphocytic Mg concentrations and the urinary Mg excretion were similar in all three groups. In five patients treated with MgSO4 there was a large increase in the serum Mg concentration and in the urinary Mg excretion. The intralymphocytic Mg concentration remained remarkably stable. CONCLUSIONS: Our data does not support the conclusion that Mg deficiency is the primary cause of pre-eclampsia.

Cross-Sectional Studies↗
PubMed1992

Effect of magnesium on phosphorus and calcium metabolism.

Magnesium is an element that occurs ubiquitously in nature. Magnesium and calcium metabolism are closely related. The intestinal absorption and the renal excretion of the two ions are interdependent. The relationship between phosphorus and magnesium metabolism is more difficult to demonstrate. The most frequent causes of hypomagnesemia in children are reduced intake, impaired intestinal absorption, renal loss and genetic diseases. Hypomagnesemia is reflected clinically in the nervous system, and there are neurophysiological and metabolic changes. Severe hypomagnesemia induces secondary hypocalcemia in most experimental animals except rats. Furthermore, severe hypomagnesemia induces functional hypoparathyroidism. In vitro studies have demonstrated that magnesium can modulate parathyroid hormone (PTH) secretion in a similar way to calcium. An acute decrease in magnesium concentration stimulates PTH secretion, and an acute increase in concentration decreases secretion. Magnesium is likely to play an important role in vitamin D metabolism. Some patients with hypocalcemia and magnesium deficiency are resistant to pharmacological doses of vitamin D or may have a form of magnesium-dependent vitamin D-resistant rickets. Phosphate depletion has been observed to be accompanied by an increase in urinary magnesium and calcium. In pediatrics the syndrome of phosphate depletion is observed particularly often in premature babies, who often receive a low-P diet. Magnesium is involved in many of the biochemical reactions that take place in the cell, and particularly in processes involving the formation and utilization of ATP. Thus, at the cellular level, magnesium plays a key role in ionic transport processes.

Calcium↗
PubMed1991

Pyridoxine-dependent seizures, clinical and therapeutic aspects.

Pyridoxine-dependency is a rare autosomal recessive disorder causing a severe seizure disorder of prenatal or neonatal onset, psychomotor retardation and death in untreated patients. Treatment requires life-long supplementation with pyridoxine (vitamin B6). The underlying defect is unknown, and there is no biological marker for the disease. Clinical diagnosis is often delayed and severe neurological sequelae are common. This article summarizes both clinical and therapeutic aspects.

Female↗
PubMed1991

Anti-liver-kidney microsome antibody-positive autoimmune hepatitis associated with alopecia.

A 14-year-old girl presented with anti-liver-kidney microsome autoimmune hepatitis preceded by alopecia 3 years earlier. Both pathologies were greatly improved by immunosuppressive therapy. Alopecia is a newly reported extrahepatic manifestation of type 2 autoimmune hepatitis. Its appearance could alert the clinician to an increased risk of autoimmune hepatitis in children.

Adolescent↗
PubMed1991

Atrial natriuretic factor after heart operations in children. Relation to hemodynamic and renal parameters.

The purpose of this study was to measure changes in serum atrial natriuretic factor concentrations immediately after heart operations in children under baseline conditions and in response to continuous infusion of dopamine (2.5 and 5.0 micrograms/kg/min). During control periods, levels of atrial natriuretic factor were elevated at 190 +/- 24 and 199 +/- 36 pg/ml. The cardiac index was 2.6 L/min/m2 and the renal plasma flow was decreased to 269 +/- 41 ml/min/1.73 m2, indicating a state of renal vasoconstriction (mean renal fraction of cardiac index of 10.0% +/- 1.0%). The mean sodium fractional reabsorption was 99.0% +/- 0.2%. During dopamine infusion, atrial natriuretic factor concentrations increased to 259 +/- 57 pg/ml and to 280 +/- 56 pg/ml, with dopamine 2.5 and 5.0 micrograms/kg/min, respectively (p = not significant), whereas left atrial pressure decreased from 11.7 +/- 0.9 mm Hg during the control period to 10.1 +/- 0.9 and to 9.9 +/- 1.0 mm Hg (p less than 0.05). No correlation was found between changes in left atrial pressure and atrial natriuretic factor levels. Dopamine at 5 micrograms/kg/min increased the cardiac index to 3.0 +/- 0.2 L/min/m2 (p less than 0.001) and the renal plasma flow to 406 +/- 61 ml/min 1.73 m2 (p less than 0.001), alleviating the renal vasoconstriction. The mean urinary sodium excretion increased to 0.33 +/- 0.08 mmol/kg/hr (p less than 0.01). The atrial natriuretic factor plasma concentrations were not related to the urinary sodium excretion, renal plasma flow, or glomerular filtration rate during the control period or during dopamine treatment. These data indicate that after heart operations in children, low urinary sodium excretion occurs despite high circulating atrial natriuretic factor levels. Atrial natriuretic factor concentrations were related neither to left atrial pressures nor to the renal changes induced by dopamine.

Adolescent↗
PubMed1990

Atrial natriuretic factor in patients with congenital heart disease: correlation with hemodynamic variables.

To investigate the alpha-atrial natriuretic factor in congenital cardiac malformations, three groups of children, aged 7 months to 16 years, with different hemodynamic situations were studied during routine cardiac catheterization. Twenty-one (group I) had tetralogy of Fallot, 24 (group II) had a left to right shunt with pulmonary hypertension and 12 (control group) had a minor cardiac lesion. Alpha-atrial natriuretic factor levels were determined by a radioimmunoassay on blood samples from the inferior vena cava, right atrium, pulmonary artery, left atrium and aorta. To evaluate the effect of an acute volume load, measurements of hormone and pressures were repeated after right ventriculography. Alpha-atrial natriuretic factor levels varied over a wide range in all groups and in all chambers investigated. Nevertheless, children with pulmonary hypertension had significantly higher levels of the hormone (p less than 0.01) and were well separated from the control group, but less well from those with tetralogy of Fallot. A 50% increase of alpha-atrial natriuretic factor from the inferior vena cava to the right atrium occurred in patients with shunt lesions with pulmonary hypertension and in patients with tetralogy of Fallot (p less than 0.001) and a further 30% increase from the right atrium to the pulmonary artery (p less than 0.05). After right ventriculography, a 100% to 200% increase of alpha-atrial natriuretic factor was observed in the total sample (p less than 0.001). A positive correlation was observed between right atrial mean pressure and right atrial alpha-atrial natriuretic factor (r = 0.63) and between pulmonary artery mean pressure and pulmonary artery alpha-atrial natriuretic factor (r = 0.61).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1979

Effects of cardiac surgery on renal function in children.

In order to determine whether cardiac surgery with cardiopulmonary bypass (CPB) affects renal function in children, glomerular filtration rate (GFR and renal plasma flow (RPF) were determined preoperatively and on the second postoperative day by a single-injection, urineless technique in a randomly selected group of 10 children. The GFR was 126.7 +/- 6.8 ml. per minute per 1.73 sq. M. (mean +/- S.E.M.) before the operation and 127.4 +/- 16.2 on the second postoperative day (p = 0.95). The RPF was 541.7 +/- 80.6 ml. per minute per 1.73 sq. M. preoperatively and 536.0 +/- 82.1 on the second postoperative day (p = 0.8 to 0.9). The results in this group of 10 children indicate that renal function is not markedly altered 2 days after cardiac surgery with CPB and deep hypothermia with circulatory arrest. The study also revealed a falsely decreased creatinine clearance. This was due to an increase in postoperative plasma creatinine values, probably related to an increase in plasma noncreatinine chromogens.

Acute Kidney Injury↗
PubMed1978

[Urinary LHRH: radioimmunological assay and physiological significance].

A LHRH-like substance is detectable in the urine. It is extractable by glass powder, which suggests that it is a peptide, and it can be concentrated by anti-LHRH affinity chromatography, strongly suggesting that it is not a contaminant in the RIA. It is composed of very little intact LHRH, and the great majority appears as multiple smaller fractions, although the possibility of "urinary LHRH" being a slightly larger peptide containing a sequence similar or identical to that of LHRH has not been entirely eliminated. Urinary measurements show no correlation with the clinical state, and the widely differing values obtained using different antisera in the present study emphasize the need for in-depth antiserum binding studies prior to clinical use in the LHRH radioimmunoassay.

Adult↗
PubMed1978

25-hydroxyvitamin D and calcium levels in maternal, cord and infant serum in relation to maternal vitamin D intake.

The plasma levels of 25-hydroxyvitamin D (25-OHD), total calcium, phosphorus and proteins were measured in 40 healthy mothers and their infants at the time of delivery during the months of December and January. Calcium, phosphorus and proteins were again measured in the plasma of the infants on the fourth day of life. Vitamin D intake of the mothers during their last 3 months of pregnancy were estimated by interviews. The mean (+/-SE) plasma levels of 25-OHD was 9.0 +/- 0.9 ng/ml in the mothers and 5.05 +/- 0.4 ng/ml in cords. There was a significant correlation between mother and cord plasma levels (r = 0.75, p less than or equal to 0.001). The concentration gradient of 25-OHD plasma levels between mother and cord is higher at high 25-OHD maternal concentrations. This suggests that the placenta plays a regulating role in the 25-OHD transfer between mother and foetus. The 4-day-old infants from mothers having a suboptimal vitamin D intake (less than 150 IU/day) have a lower mean serum plasma level than infants born from mothers with a vitamin D intake of more than 500 IU/day.

Calcium↗
PubMed1978

Value of serum thyroxine measurements for the management of congenital hypothyroidism in children.

Fourteen cases of primary congenital hypothyroidism were studied and separated for the analysis purpose into two groups. Group A consisted of 7 children whose hypothyroidism was diagnosed after 1971 and the therapy by thyroid gland extracts evaluated by regular serum thyroid hormone determinations. Group B was made of 7 children whose disease was diagnosed and treated before 1971. Two periods were therefore studied in group B: first period, before any hormonal determinations (as a growth control period for group A), and second period, during which hormonal determinations were made and taken into consideration for the dosage. Although growth patterns were similar in both groups, mean thyroid extracts dose was 63 +/- 25 mg/m2/day (mean +/- SD) during follow-up with hormonal determinations, while it was markedly higher during the first period of group B (125 +/- 76, range 46.1 to 219.9 mg/m2/day). The mean dose of 63 +/- 25 mg/m2 induces a mean level of plasma thyroxine of 82 +/- 32 microgram/1 (mean +/- 1SD), a normal growth (with catch-up growth in the patients who had a retarded growth), and a good psychomotor development. Regular measurements of serum thyroxine during therapy seems to be a valid parameter for determining the dose of thyroid gland extracts necessary for adequate substitution. Serum=1-triiodo-thyronine levels have more fluctuations than thyroxine. Serum TSH mainly prevents the underdose of patients but cannot help in case of overdose. The suggested dose for treatment of such patients is 88 mg/m2/day (= 63 + 1SD).

Body Weight↗
PubMed1977

The secretion of adrenal androgens and growth patterns of patients with hypogonadotropic hypogonadism and isiopathic delayed puberty.

Plasma concentrations of adrenal androgens (DHEA and DHEA-S) and the growth patterns of four male patients with hypogonadotropic hypogonadism have been compared and contrasted with those of eight male patients wit idiopathic delayed puberty. As a group the patients with HH presented at an older age with delayed puberty and normal heights; the growth rate and pattern have been normal except for an absence of the pubertal growth spurt. Adrenal androgens were usually normal for chronologic age and high for bone age. The patients with IDP presented at a younger age, usually with short stature, low adrenal androgens relative to the chronologic age, but normal relative to the bone age. Patients with IDP appear to exhibit a delay in maturation of both the adrenal cortex and the hypothalamo-pituitary gonadal axis usually with short stature and retardation of the bone age. The importance in measurements of adrenal androgens in the diagnosis of HH and of IDP is emphasized.

Adolescent↗
PubMed1977

Effects of parathyroid hormone on total protein, calcium magnesium, phosphorus, sodium and potassium concentrations of normal human parotid saliva.

The effects of parathyroid hormone (PTH) administered to six young normal adult subjects on protein, calcium, magnesium, phosphorus, sodium and potassium concentrations in parotid saliva have been studied in relation to the salivary flow rate. Stensen's duct was cannulated and excretion patterns of the constituents determined before and after stimulation of saliva production by lemon juice. After a control period (period 1), 50 U of PTH were given i.v. followed by an infusion of 2 U/min for 60-90 min (period 2). In the absence of any detectable changes in plasma, PTH induced a significant rise of salivary protein, calcium, and phosphorus concentrations at rest and following lemon juice stimulation, and of sodium concentration, but only at high flow rates for the latter. PTH did not change magnesium and potassium excretions significantly. Control experiments without PTH were performed on five other subjects. Protein, phosphorus and potassium concentrations did not change significantly between period 1 and period 2. Calcium and sodium excretions were reduced and magnesium excretion increased during period 2. These results provide evidence that PTH acts on the parotid gland by affecting protein secretion and electrolyte transport. Possible mechanisms of these changes are discussed.

Adult↗