Biomedical subjects
Publications and source records attributed to L David.
In children with pseudo or true hermaphroditisms genitography is easy to perform and reliable. This examination helps in determining the morphological sex and becomes necessary if surgery of the genital tract is considered.
Twenty-six cases of neonatal torsion of spermatic cord were studied and compared to 171 cases reported in the literature. In a few cases, the torsion was antenatal and this may explain some absent testes. Diagnosis is sometimes difficult to make; symptoms were comparable to those in other disorders: peritoneo-vaginal tunnel, testicular inflammation or testicular tumor. In these cases, surgery can make the exact diagnosis although it cannot save the testis even if it is performed early.
Immunoreactivities to endogenous calcitonin, endogenous parathyroid hormone, endogenous estradiol and estradiol receptors were studied in osteoblasts from the calvaria of neonatal mice by immunocytochemistry with the use of ultrathin sections obtained by cryo-ultramicrotomy. Tissues were fixed in glutaraldehyde, postfixed in osmium tetroxide and frozen in liquid nitrogen. Estradiol and estradiol receptors could not be detected in osteoblasts, whereas calcitonin- and parathyroid hormone-like immunoreactivities were observed in this cell type. Calcitonin and parathyroid hormone had similar subcellular localizations: immunoreactivities were observed at the plasma-membrane level, in the cytoplasmic matrix, and in the nucleus. These results provide immunocytological evidence for: 1) the internalization of calcitonin and parathyroid hormone in osteoblasts; 2) a direct participation of calcitonin and parathyroid hormone in the regulation of osteoblasts; 3) the absence of estradiol receptors and estradiol in osteoblasts.
The effect of two doses of Phosphorus (P) supplementation to pooled breast milk (BM): 0.48 and 0.800 mmol/kg/24 h given during the second month of life was evaluated in 22 very low birthweight infants. The concentration of calcium and phosphorus in serum and urine, the serum concentration of immunoreactive parathyroid hormone (iPTH) and the plasma 1,25-dihydroxy-vitamin D concentration (1,25-OH-D) were compared to the values in 19 control infants. The mean +/- SD concentrations in control infants and adults are 63 +/- 18 microliters Eq/ml for serum iPTH and 85 +/- pmol/l for plasma 1,25-OH-D. With 0.48 P supplementation, urinary Ca (UCa) excretion (median and range) 0.238 mmol/kg/24 h (0.105-0.520) was lower than in the control group 0.288 (0.205-0.679) (p less than 0.05); the reduction of UCa was larger with 0.8 P supplementation: 0.047 (0.023-0.163) (p less than 0.01). P supplementation induced no change in serum Ca concentration but a slight and significant increase in serum iPTH was observed only with the 0.8 P supplementation: 55 microliters Eq/ml (less than 25-80) (p less than 0.05). With 0.8 P supplementation there was no significant change of plasma 1,25-OH-D concentration: 173 pmol/l (106-271) vs. 255 (132-293) in the control group. These data show that with 0.8 P supplementation, the hypercalciuria in BM-fed infant disappears without secondary hyperparathyroidism, but without any change in plasma 1,25-OH-D concentration.
A new polyether antibiotic, abierixin, was found in the mycelium of a culture broth of nigericin-producing Streptomyces albus NRRL B-1865. Abierixin was extracted with organic solvents and purified by column chromatography and HPLC. The structure of abierixin was determined by FAB/MS/MS and CI/MS/MS and 1H and 13C NMR spectrometries. Abierixin exhibited weak antimicrobial and ionophorous activities, low toxicity but good anticoccidial activity. Nigericin biosynthesis from abierixin is discussed.
A case of pericarditis following meningococcal meningitis in a 19 month old boy is presented. First clinical signs were noted after 5 days of antibiotherapy (Cefotaxime); at that time the meningitis was cured and the bacteriologic studies yielded negative results. Complete clinical recovery was obtained within 24 hours of treatment with prednisone (2 mg/kg), antibiotherapy being stopped 4 days earlier. The pathogenesis of post meningococcal pericarditis is discussed based on the data from the literature. This observation adds support to an immuno-allergic origin of this pericarditis.
Hypercalcemia (serum Ca greater than or equal to 2.83 mmol/l) was detected in 10 premature infants (gestational age: 31-37 weeks and birthweight: 1100-1950 g). All were fed with pooled human breast milk. Urinary Ca excretion was high (greater than 0.200 mmol/kg/24 h) in all but one infant while serum phosphorus (P) concentration and urinary P excretion were low. Serum immunoreactive parathyroid hormone and plasma 25-hydroxyvitamin-D concentrations were normal. A significant positive correlation was found between serum Ca concentration and urinary Ca excretion, and a negative correlation between serum Ca concentration and serum P concentration or urinary P excretion. Hypercalcemia disappeared spontaneously in two patients, was corrected by a humanized milk in three patients and by P supplementation in five patients. These data suggest that neonatal hypercalcemia is related to P depletion induced by human breast milk in premature infants.
A 7 years old girl with Rothmund-Thomson syndrome is described. A detailed study of the dermatologic lesions has been performed. The parent's girl are first cousins and one of her brothers, also having the Rothmund-Thomson syndrome, died from an osteosarcoma of the tibia at the age of 11. This familial observation gives support to the uniqueness of the Rothmund-Thomson syndrome with autosomal recessive inheritance.
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Vaginal bleeding in young girls without other signs of precocious sexual development is rare. We report a series of 33 cases observed during a 21 year period in the departments of pediatrics of the University of Lyon. Among the various etiologies, vaginal foreign bodies (10 cases, 30%) and vaginitis (10 cases, 30%) were the most frequent. There were 3 cases of benign vulvar tumors (9%) and 3 cases of malignant vaginal tumors (9%). In 3 cases the vaginal bleeding remained apparently idiopathic leading to the diagnosis of premature menarche. A retrospective evaluation of each case showed that history, physical examination and colposcopy would have rapidly established the correct diagnosis in 80 to 85% of cases; it is therefore concluded that laboratory and complex gynecologic investigations should be considered only after negative findings from these simple clinical tools in the evaluation of vaginal bleeding in prepubertal girls.
In order to investigate the mechanism whereby oral propranolol administration reduces the increased rate of urinary hydroxyproline excretion (UHxE) of patients with hyperthyroidism, a comparison was made of the effects of the oral administration of propranolol-timolol, propylthiouracil (PTU), and a placebo to patients with hyperthyroidism and to normal controls. Propranolol decreased the pulse rate (P less than 0.01), serum triiodothyronine (T3) level (P less than 0.05), and UHxE (P less than 0.01) without modifying the serum free thyroxine index (FT4I) or parathormone (PTH) level. Timolol decreased the pulse rate (P less than 0.01) to the same extent as propranolol, had no effect on T3, FT4I, or PTH, and failed to decrease UHxE. Administration of PTU decreased the T3 level (P less than 0.05) to a similar extent as propranolol without modifying the FT4I or PTH level and had no effect on UHxE. Placebo administration had no effect. These results suggest that the reduction of UHxE by propranolol is not due to the beta-receptor-blocking properties of propranolol nor mediated by the propranolol-induced decrease in the level of T3 but is probably due to the membrane-stabilizing properties of propranolol.
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The mineral metabolism in the fetus and pregnant woman is described with reference to data from the medical literature and personal studies. As soon as the twenty-eighth week of gestation, a concentration gradient is established between mother and fetus for calcium, phosphorus and magnesium, with higher levels in the fetus. The vitamin D content of the fetus is dependent on that of the mother; in France, where food is not supplemented, vitamin D deficiency is common in mothers and neonates, especially during the winter and spring and in areas where sunlight is scarce. Vitamin D supplementation is therefore required during the last trimester of gestation.
A young man with hypogonadotropic hypogonadism treated with hCG had resistance to this therapy and was found to have antibodies to hCG. We subsequently sought, using a sensitive radioimmunological method, anti-hCG antibodies in plasma from eight other hCG-treated children shown to have isolated hypogonadotropic hypogonadism. Antibodies to hCG were found in four of the nine. These antibodies were associated with the immunoglobulin fraction of plasma. In one patient antibodies were detected for 5 yr after therapy was discontinued. The titer and affinity constants of these antibodies were notably influenced by the therapeutic regimen used: the titer was significantly decreased and the affinity constant was lowered after reinstitution of therapy with larger hCG doses. In one patient the presence of anti-hCG antibody was associated with the failure to respond to hCG therapy.
Twenty-two infants of diabetic mothers (IDM) were studied and were divided into two groups: a first group of 14 IDM did not receive vitamin D3 and was studied at birth and at 2, 24, 48 and 120 hours; a second group was given daily dosage of 60 microgram of vitamin D3 from 3 hours to 120 hours and was studied at 2 hours and 120 hours. In the first group, serum calcium levels decreased markedly during the first 24 hours of life (mean +/- SD: 1.77 +/- 0.3 mmol/l, p less than 0.01) and remained low at 5 days. Serum phosphorus levels remained normal but serum magnesium levels decreased significantly at 24 hours (mean +/- SD: 0.64 +/- 0.108 mmol/l, p less than 0.01) and returned to normal at 5 days. Serum immunoreactive parathormone levels increased consistently to high levels at 24 hours and remained elevated at 120 hours (p less than 0.001). Serum immunoreactive calcitonin levels increased at 24 hours (p less than 0.001) and decreased at 120 hours to low or undetectable values in all infants. In group II, serum 25O-HD levels and 1.25 OH2 D levels increased significantly (p less than 0.001) respectively to 27.2 +/- 2.7 ng/ml and 114 +/- 20 pg/ml at 5 days. The results of this study show hypocalcemia to be a common event in IDM during the first days of life and furthermore hypophosphatemia, hypoparathyroidism, hypomagnesemia or defect of vitamin D metabolism would not seem to be the main etiological factors.
To assess the relationship between maternal and fetal mineral homeostasis, serum calcium, magnesium, inorganic phosphate, parathyroid hormone, and vitamin D metabolite concentrations in venous cord sera from 15 preterm singletons and 3 twin pairs were compared with the levels found in maternal sera. Cord calcium, magnesium, and phosphorus levels were significantly higher than the respective levels in maternal samples. There was a significant relationship between the two compartments for all three analyses. Cord serum 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D levels were significantly lower than those observed for the mothers. Association of the cord concentration with that of the mothers was observed only for the first two metabolites. There was no relationship between the maternal 1,25-dihydroxyvitamin D levels and gestational age, calcium, magnesium, inorganic phosphate, or 25-hydroxyvitamin D. Cord 1,25-dihydroxyvitamin D correlated significantly only with cord calcium levels. Immunoreactive parathyroid hormone levels were within normal limits both in cord and maternal samples. Our data suggest that after 31 weeks of gestation: (1) calcium, magnesium, and inorganic phosphate cross the placental barrier against a concentration gradient; (2) the fetus depends on the maternal supply for 25-hydroxyvitamin D and 24,25 dihydroxyvitamin D; (3) the feto-placental unit synthesizes 1,25-dihydroxyvitamin D according to fetal needs.
For five days, three groups of six premature infants each were fed human milk and given a daily dosage of one of the following: vitamin D3 (30 micrograms), 25-OH D3 (10 micrograms) and 1,25-OH D3 (0.5 micrograms). The infants in the groups were matched for gestational age and birthweight. Administration of 25-OH De or 1,25-(OH)2 D3 did not significantly modify the course of early neonatal hypocalcemia as compared with infants receiving vitamin C3. Mean plasma Ca +/- S. D. (mg/100 ml) decreased to nadir values at 48 hr (D3: 5.7 +/-1.2; 25 OH D3: 6.8 +/- 0.9; 1.25-(OH)2 D3: 6.7 +/-1.1). A progressive increase toward normal values was seen at 120 and 168 hr in the three groups. Mean plasma immunoreactive parathyroid hormone +/- S.D. (microliters Eq/ml) followed an opposite pattern with peak values at 48 hr (D3: 231 +/- 137; 25-OH D3: 281 +/- 138; 1,25-(OH)2 D3:211 +/- 149). Mean plasma +/- S.D. 25-OH values (ng/ml) were low at 1.2 hr (8.7 +/- 4.8) n: 16) and increased significantly after 7 days of D3 (18.2 +/- 4.2 P less than 0.001) and 25-OH D3 administration (46 +/- 10.3 P less than 0.001)/Mean plasma iCT +/- S.D. (pg/ml) reached peak values at 24 hr (D3: 457 +/- 186; 25-OH D3: 415 +/- 121; 1.25-(OH)2 D3: 443 +/- 183). These data suggest that the various forms of vitamin D are well absorbed in preterm infants and that administration of vitamin D metabolites during the first days of life is not warranted for they prophylaxis of early neonatal hypocalcemia.