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Biomedical subjects

L Paunier

Publications and source records attributed to L Paunier.

At least 55 records · Page 3Linked to original sources

[Phosphorus-calcium metabolism and plasma 25-hydroxycholecalciferol in intestinal malabsorption].

One hundred and four children aged 0-15 years, with suspicion of malabsorption were studied. They had a proximal jejunal biopsy and, at the same time, the following measurements: 25-hydroxycholecalciferol (25-OH-CC), calcium, phosphorus and serum alkaline phosphatase, bone age on X-ray of the left hand and wrist, cortical thickness of the 2nd, 3rd, 4th metacarpal bones. For the analysis of the results, the patients were divided into two groups according to the season (winter vs. summer). None of the patients in either group had clinical or radiological signs of rickets. The following results were obtained: 1. The 25-OH-CC serum levels were significantly lower during the winter than during the summer months. This was observed more frequently in the cases with atrophy of the jejunal mucosa. 2. During the summer, the 25-OH-CC serum levels were not different in the cases with normal or pathological mucosa. This demonstrates the importance of the skin synthesis of vitamin D during the summer months. 3. The mean of the serum calcium levels was significantly lower in the group of children with atrophy of the jejunal mucosa than in children with normal intestinal biopsy. The serum calcium levels were not correlated with the serum 25-OH-CC levels. 4. The serum phosphorus levels were significantly lowered during the winter months in the children aged 0-3 years with pathological jejunal biopsy. 5. The serum alkaline phosphatase levels were lowered in cases of total atrophy of the jejunal epithelium cells. 6. Cortical thickness of the metacarpal bones becomes thinner with the progression of the alteration of the jejunal epithelium cells, independently of season or age. However, only the group of children aged 0-3 years studied during the winter months and with total atrophy of the jejunal mucosa have a significantly diminished cortical thickness of the metacarpal bones. The lowering of the calcium levels and the decrease of the cortical thickness are probably secondary to an impaired intestinal absorption of calcium. In the syndrome of malabsorption, the integrity of the jejunal epithelial cells seems to play a more important role than a vitamin D deficiency in the genesis of this calcium malabsorption.

Adolescent↗

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↗

[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↗

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↗

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↗

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↗

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↗

Radioimmunoassay of melatonin: human serum and cerebrospinal fluid.

Using a newly characterized anti-melatonin serum it has been possible to establish human serum melatonin concentrations at short time intervals during 24h. A clear circadian rhythm with peak values during the dark phase was demonstrated in both men and women. Values (pg/ml;mean +/- SE) were as follows: females 02.00h: 130 +/- 7, 18.00h: 45 +/- 5 males 02.00h: 140 +/- 11, 18,00H: 70 +/- 5. The estimation (pg/ml; mean +/- SE) of melatonin in human serum (males: 63 +/- 22 and females: 100 +/- 45) and cerebrospinal fluid simultaneously taken has shown that melatonin is lower in cerebrospinal fluid (males: 59 +/- 33 and females: 57 +/- 28). Blanks are not subtracted.

Adult↗

[Changes in serum and urinary magnesium during and after extracorporeal circulation in cardiac surgery in children].

Magnesium plays an essential role in the processes of myocardial contraction and conduction. In cardiovascular surgery, extracorporeal circulation (ECC) in haemodilution results in various electrolyte distrubances, with invariably hypomagnesaemia. A group of 13 children undergoing open heart surgery was compared with a group of 17 children operated upon under the same conditions but with the addition of magnesium to the filling solution for the extracorporeal circulation. Changes in blood and urinary electrolytes during and after ECC were studied. Hypomagnesaemia was seen in both groups after surgery but the provision of magnesium supplements shortened the duration. In addition, blood phosphate levels remained significantly higher in the group receiving magnesium. The significance of these various findings is discussed and a technique for the provision of magnesium supplements is proposed.

Adolescent↗

Asymptomatic chronic hypomagnesemia and hypokalemia in a child: Cell membrane disease.

An 8-year-old boy was followed for four years because of chronic hypomagnesemia and hypokalemia. THe clinical manifestations were episodic and characterized by spontaneous carpopedal spasm. There were no other signs of magnesium or potassium deficiency. Metabolic studies revealed that the urinary exceretion of magnesium and potassium was elevated in relation to the serum level, but appropriate for a normal boy of that age. No abnormality was detected in the renin-angiotensin-aldosterone system, and the renal functions were normal. Various therapeutic attempts (oral magnesium and/or potassium supplements, spironolactone) failed to correct the abnormal serum concentrations of magnesium and potassium. This disease may represent a defect in the maintenance of a normal gradient between intra-and extracellular magnesium and potassium.

Aldosterone↗

Hormonal changes during puberty. IV. Longitudinal study of acrenal androgen secretions.

Longitudinal studies of plasma dehydroepiandrosterone sulfate (DHEA-S) and dehydroepiandrosterone (DHEA) were made in 13 girls aged 7 years and 14 aged 10 years, during 3 years, at 6-month intervals. Similarly, two groups of 12 boys aged 8 years and 11 years were followed. In addition, 3 girls with premature adrenarche and 4 male patients with Addison's disease were studied. In the normal girls a significant rise of plasma DHEA-S and DHEA occurred from 6 years of bone age (51.4 +/- 9.0 ng/ml and 50.5 +/-9.2 ng/100 ml, respectively) to 8 years (119. 7 +/- 19.1 ng/ml and 94.5 +/- 16.5 ng/100 ml). A further significant rise was apparent at 11 years (385.8 +/-60.9 ng/ml) and 329.0 +/- 78.4 ng/100 ml). In boys, a similar rise of DHEA-S and DHEA was observed between 6 years of bone age (75.8 %/- 12 ng/ml and 44.3 +/- 7.6 ng/100 ml) and 8 years (157.4 +/- 28.9 ng/ml and 76.1 +/- 8.9 ng/100 ml). Furhter significant rise of DHEA-S and DHEA were seen at 13 years of bone age (563.7 +/- 123.7 ng/ml and 267.9 +/- 50.0 ng/100 ml, respectively). Testosterone in both sexes rose 2-3 years later than DHEA-S and DHEA. In female patients with premature adrenarche, higher plasma levels of DHEA-S and DHEA were found when compared to normal levels at similar chronological and bone ages. Very low plasma concentrations of DHEA-S and DHEA were obsrved in the patients with Addison's disease.

Addison Disease↗

Human serum melatonin changes during the menstrual cycle.

Serum melatonin concentration in early morning during the menstrual cycle, studied in five healthy women, showed that melatonin was elevated at the time of menstrual bleeding and had its nadir at the time of the menstrual cycling in humans.

Adult↗