Pathophysiology of calcium metabolism in children with vitamin D-deficiency rickets.

Objective: To improve understanding of the biochemical events in vitamin D-deficiency rickets (VDR).

Methods: We investigated 51 untreated patients, 2 to 36 months of age, during three stages of VDR. Nineteen of these patients were also studied during therapy with 5000 to 10,000 U vitamin D3 (cholecalciferol) and 0.

Pseudohypoparathyroidism type Ib is not caused by mutations in the coding exons of the human parathyroid hormone (PTH)/PTH-related peptide receptor gene.

Pseudohypoparathyroidism type Ib (PHP-Ib) is thought to be caused by a PTH/PTH-related peptide (PTHrP) receptor defect. To search for receptor mutations in genomic DNA from 17 PHP-Ib patients, three recently isolated human genomic DNA clones were further characterized by restriction enzyme mapping and nucleotide sequencing across intron/exon borders. Regions including all 14 coding exons and their splice junctions were amplified by polymerase chain reaction, and the products were analyzed by either temperature gradient gel electrophoresis or direct nucleotide sequencing.

A constitutively active mutant PTH-PTHrP receptor in Jansen-type metaphyseal chondrodysplasia.

A single heterozygous nucleotide exchange in exon M2 of the gene encoding the parathyroid hormone-parathyroid hormone-related peptide (PTH-PTHrP) receptor was identified in a patient with Jansen-type metaphyseal chondrodysplasia, which changes a strictly conserved histidine residue at position 223 in the receptor's first intracellular loop to arginine. Constitutive, ligand-independent adenosine 3',5'-monophosphate accumulation was observed in COS-7 cells expressing the mutant PTH-PTHrP receptor but not in cells expressing the wild-type receptor. This finding explains the severe ligand-independent hypercalcemia and hypophosphatemia, and most likely the abnormal formation of endochondral bone, in this rare form of short-limbed dwarfism.

Healing of rickets during vitamin D therapy despite defective vitamin D receptors in two siblings with vitamin D-dependent rickets type II.

We report the healing of severe rickets despite hypocalcemia in two siblings with absent vitamin D receptors; long periods of treatment with excessive doses of vitamin D led to relative hypoparathyroidism and a return to normal of calcium metabolism during calcitriol treatment. This finding suggests that some other regulating factor may substitute for the defective vitamin D receptor.

Increased urinary excretion of collagen crosslinks in girls with Ullrich-Turner syndrome.

Skeletal abnormalities and "osteoporosis" are frequent features of Ullrich-Turner syndrome (UTS), but their cause remains largely unknown. In this study, we compared the urinary excretion of hydroxyproline (OHP), pyridinoline (PYD) and deoxypyridinoline (DPD) in 28 girls (bone age 3.5-11.

Dose-dependent responses in insulin-like growth factors, insulin-like growth factor-binding protein-3 and parameters of bone metabolism to growth hormone therapy in young adults with growth hormone deficiency.

There is increasing awareness that growth hormone (GH) replacement therapy is also essential in adult patients with growth hormone deficiency (GHD). There are little data available on the dose requirements for replacement therapy in this age group. In childhood, the growth response to GH therapy can serve as an indicator for correct replacement dose.

[Calcitriol administration during pregnancy in a partial DiGeorge anomaly].

A 23-year-old pregnant woman was known since birth to have partial DiGeorge syndrome with idiopathic hypoparathyroidism and clinically suspected thymus hypoplasia. The hypocalcaemia had until recently been treated with 1000 IU vitamin D3 daily. During the 9th week of pregnancy the serum calcium level was 1.

[Minor head injuries. Prognostic factors in the evaluation of patients].

In order to identify signs to be used in the decision whether or not to admit patients after minor head injuries (MHI), the records of 713 females and 1163 males were reviewed. Skull X-ray was not obtained routinely, all patients were able to talk and walk when they reached medical contact. Nine patients developed an intracranial complication, three had an operation and one died.

Teratogenic effects in a case of maternal treatment for acute myelocytic leukaemia--neonatal and infantile course.

Experience with the use of cytotoxic drugs in the first trimester of pregnancy is limited. We report on the clinical phenotype and infantile development of a girl born to a 36-year-old mother. Before recognition of pregnancy, the latter had been treated for acute myelocytic leukaemia receiving cytarabine, daunorubicin and doxorubicin at conception and cytarabine and thioguanine at about 35-37 days post conception.

Diabetes-related end-stage renal disease in Missouri: trends and variations by age and race.

Diabetes-related end-stage renal disease (ESRD-DM) is a major source of morbidity and medical costs. The authors studied patterns of ESRD-DM in Missouri during the period 1985-1992. The incidence of ESRD-DM increased during this period, with the largest increase in older age groups.

High-molecular-mass or macromolecular alkaline phosphatase in sera of children with solid tumors.

High-molecular-mass alkaline phosphatase (H-Mr AP) was detected in sera from children with solid tumors without liver metastases. H-Mr AP activities were determined by a liquid chromatographic and an electrophoretic method. In 5 out of 10 cases with solid tumors--Ewing sarcoma (n = 2), neuroblastoma (n = 2), and rhabdoid tumor (n = 1)--H-Mr AP activities ranged from 3.

Calcium metabolism in the Jansen type of metaphyseal dysplasia.

The Jansen type of metaphyseal dysplasia (JMD) is a rare disorder characterized by growth disturbance and progressive metaphyseal changes initially reminiscent of rickets or primary hyperparathyroidism. Seven of the 16 patients described until now presented with hypercalcaemia of unknown origin. We report studies of calcium metabolism in a hypercalcaemic girl with JMD during the first 3 years of life.

Prognostic signs in the evaluation of patients with minor head injury.

To assess signs that might be used in the decision whether or not to admit a patient with minor head injury, the records of 713 female and 1163 male patients were reviewed. Skull radiographs were not obtained routinely; all patients were able to walk and talk when they reached medical contact. Nine patients developed an intracranial complication.

Selective protein degradation in the yeast exocytic pathway.

Protein degradation in the exocytic pathway was studied in Saccharomyces cerevisiae using human alpha-1-protease inhibitor (A1Pi) as a reporter molecule. Yeast cells transformed with A1Pi cDNA genes synthesized A1Pi that entered the secretion pathway and accumulated in the endoplasmic reticulum (ER). Cells expressing A1PiM (wild-type) accumulated about 10-fold more A1Pi than cells expressing A1PiZ (secretion defective variant).

Single strand conformation polymorphism analysis of androgen receptor gene mutations in patients with androgen insensitivity syndromes: application for diagnosis, genetic counseling, and therapy.

Recent studies indicate that mutations in the androgen receptor gene are associated with androgen insensitivity syndromes, a heterogeneous group of related disorders involving defective sexual differentiation in karyotypic males. In this report, we address the possibility of rapid mutational analysis of the androgen receptor gene for initial diagnosis, genetic counseling, and molecular subclassification of affected patients and their families. DNA from peripheral blood leukocytes of six patients from five families with various degrees of androgen insensitivity was studied.

Endocrine and molecular biological studies in a German family with Albright hereditary osteodystrophy.

We examined a German family with five members affected by Albright hereditary osteodystrophy (AHO). The only patient with pseudohypoparathyroidism type Ia (PHP-Ia) presented clinically with latent tetany, mental retardation, round face, short stature, brachymetacarpia and calcifications of subcutaneous tissue, heart and brain, whereas all other four members with pseudopseudohypoparathyroidism (pseudo-PHP) showed only subcutaneous calcifications and brachymetaphalangia. The PHP-Ia patient exhibited hypocalcaemia, hyperphosphataemia, elevated immunoreactive parathyroid hormone (PTH), and a blunted response of cyclic adenosine monophosphate (cAMP) in plasma and urine to synthetic 1-38 hPTH.

Elevated 1,25-dihydroxyvitamin D serum concentrations in infants with subcutaneous fat necrosis.

Two infants with subcutaneous fat necrosis had hypercalcemia that normalized during glucocorticoid treatment. The combination of hypercalcemia, normal concentration of 25-hydroxyvitamin D, an elevated concentration of 1,25-dihydroxyvitamin D, a suppressed parathyroid hormone level, and low-normal bone turnover indicated abnormal 1,25-dihydroxyvitamin D production with increased intestinal absorption of calcium. Unregulated production of 1,25-dihydroxyvitamin D by the granulomatous cells of fat necrosis may cause hypercalcemia.

Calcium metabolism in Williams-Beuren syndrome.

Increased 1,25-dihydroxyvitamin D levels and decreased basal and calcium-stimulated calcitonin serum levels have been found in children with Williams-Beuren syndrome (WBS). To determine whether isolated or combined disturbances of secretion or action of the calcium-regulating hormones may cause the tendency to hypercalcemia in WBS, we investigated several aspects of calcium metabolism in 27 normocalcemic children and adults, aged 2 to 47 years, with WBS. With the exception of slightly decreased 25-hydroxyvitamin D and slightly increased calcitonin in serum, all measured basal indexes of calcium and bone metabolism, including the serum levels of intact parathyroid hormone and 1,25-dihydroxyvitamin D, were comparable to control values.