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Biomedical subjects

D Aarskog

Publications and source records attributed to D Aarskog.

At least 73 records · Page 4Linked to original sources

Vitamin D metabolism in hypophosphatasia.

A 4-month-old boy with the infantile form of hypophosphatasia was followed for 9 months with measurements of serum calcium, phosphate, alkaline phosphatase and various vitamin D metabolites, together with urinary excretion of cyclic AMP. During the initial hypercalcemic stage the serum concentration of 25-hydroxyvitamin D was normal. Urinary cyclic AMP was low and the serum concentration of the dihydroxymetabolites of vitamin D were appropriate to the high serum calcium with low 1,25-(OH)2D and relatively high 24,25(OH)2D and 25,26(OH)2D levels. Due to restrictions of the vitamin D intake and lack of exposure to sun he developed vitamin D-deficiency rickets at 9 months of age with very low serum concentration of 25-hydroxyvitamin D and markedly increased urinary excretion of cyclic AMP. Following vitamin D treatment the serum level of 1,25(OH)2D showed a brisk rise to a considerably elevated value. Initially the serum concentration of alkaline phosphatase was well below the normal range, rose markedly during the stage of active rickets and returned to the characteristic low levels of hypophosphatasia with healing of the rickets.

Calcium↗

Plasma concentrations of vitamin D metabolites in puberty: effect of sexual maturation and implications for growth.

To relate the vitamin D metabolism in puberty to sex, sexual maturation, and, indirectly, to growth velocity and cessation of growth, the plasma level of 25-hydroxy vitamin D, 1,25-dihydroxyvitamin D [1,25-(OH)2D], 24,25-dihydroxyvitamin D [24,25-(OH)2D], and 25,26-(OH)2D were measured in 191 adolescents representing all stages of puberty. In girls, 1,25-(OH)2D3 increased from age 11 yr to a peak at 12 yr of age (P less than 0.0005) and then decreased. In boys, the increase occurred between 13--14 yr of age (P less than 0.005), with a subsequent decline. When the 1,25-(OH)2D concentrations were related to the stage of puberty, the girls showed a maximal increase between stages 1 and 2 (P less than 0.0005), with a peak at stage 3, whereas the boys had a significant increase from stage 2 to a peak at stage 3 (P less than 0.01). In both sexes, there were subsequent significantly decreasing values to stage 4 through stage 5. The ratio of 24,25-(OH)2D to 25-hydroxyvitamin D varied inversely with the 1,25-(OH)2D concentration, with the lowest value at age 12 yr in both sexes, followed by a gradual increase to a plateau at age 15 yr in girls and 17 yr in boys. It appears that the hormones of the vitamin D system add another dimension to the endocrinology of growth and puberty.

24,25-Dihydroxyvitamin D 3↗

Vitamin D metabolism in idiopathic infantile hypercalcemia.

A 9-month-old boy who had the mild form of idiopathic infantile hypercalcemia was observed for 18 months. During the initial hypercalcemic stage, the serum concentration of 25-hydroxyvitamin D was normal. Urinary levels of cyclic adenosine monophosphate (cAMP) were low, and the serum concentrations of the dihydroxyl metabolites of vitamin D were appropriate to the high serum calcium concentration, with low 1,25-dihydroxyvitamin D and relatively high 24,25- and 25,26-dihydroxyvitamin D levels. Throughout the study period, there was a close positive correlation between the magnitude of the urinary cAMP excretion and the serum level of 1,25-dihydroxyvitamin D. The results indicate that excessive vitamin D intake leading to high serum levels of 25-hydroxyvitamin D are not decisive factors in the pathogenesis of idiopathic infantile hypercalcemia.

24,25-Dihydroxyvitamin D 3↗

Effect of parathyroid hormone on vitamin D metabolism in osteopetrosis.

Indices of vitamin D metabolism were studied before and after infusion of bovine parathyroid hormone extract in three children with osteopetrosis. Basal serum concentrations of calcium, alkaline phosphatase, and 25-hydroxyvitamin D tended to be low. Serum immunoreactive parathyroid hormone levels were in the upper normal range in two patients. A marked increase in urinary cyclic adenosine 3':5'-monophosphate (cAMP) in all patients was solely due to an increase in the nephrogenous cAMP. The basal concentration of 1,25-dihydroxyvitamin D was clearly more than the upper limit of normal range in all three patients and increased after parathyroid extract infusion in one patient. The basal serum levels of 24,25-dihydroxyvitamin D were within normal limits and tended to decrease after parathyroid extract infusion in two of the patients. Parathyroid hormone and 1,25-dihydroxyvitamin D act in concert to increase calcium resorption from bone, and the increased serum levels of both these factors may reflect lack, or unresponsiveness, of target cells in bone.

Child↗

Syndrome of hydrocephalus, costovertebral dysplasia and Sprengel anomaly with autosomal dominant inheritance.

A malformation syndrome affecting a mother and her three daughters is reported. The patients showed various combinations of the following malformations and anomalies: spontaneously arrested communicating hydrocephalus, costovertebral dysplasia, Sprengel anomaly (undescended scapula), hypertelorism, broad and low nasal bridge, anteverted nostrils, low-set ears, high-arched palate, prominent mandibula, enamel hypoplasia and increased interspace between the 1st and 2nd toes. The occurrence of similar abnormalities in the mother and her three daughters and the variable expression of the manifestations indicate that the syndrome was inherited as an autosomal dominant trait.

Abnormalities, Multiple↗

Vitamin D metabolites in serum from hypoparathyroid patients treated with vitamin D2 and 1 alpha-hydroxyvitamin D3.

Vitamin D and its metabolites 25-hydroxyvitamin D (25OHD), 24,25-dihydroxyvitamin D [24,25-(OH)2D], 25,26-(OH)2D, and 1,25-(OH)2D were measured after separation on high pressure liquid chromatography in sera from two hypoparathyroid patients treated with high doses of vitamin D2. Fractions with displacement activities in the competitive protein-binding assays were found which were not detectable in sera from controls not supplemented with vitamin D2. These fractions, presumably representing vitamin D2 metabolites, were quantitated separately from the vitamin D3 metabolites. After a change of treatment from milligram doses of vitamin D2 to microgram doses of 1 alpha OHD3, the serum metabolites of vitamin D2 and vitamin D3 were followed from 8-13 months. During the first 2-3 months, there was an initial relatively rapid fall in serum vitamin D2 levels and metabolites, followed by a slower decline. High levels of vitamin D2 metabolites were still present after 13 months. Taking into account the marked preponderance of 25OHD2 to 25OHD3, the relative concentration of (OH)2D3 metabolites were higher than expected, which might indicate a preferential 25OHD3 hydroxylation or alternatively, a more rapid degradation of vitamin D2 metabolites in these patients. The high and sustained release of vitamin D2, presumably from fat stores, more than a year after vitamin D2 ingestion was stopped has obvious clinical implications and should be considered in the long term follow-up of patients shifted from the traditional high doses of vitamin D to the newly synthesized 1 alpha OHD3 or 1,25(OH)2D3.

Adult↗

Effect of parathyroid hormone on 1,25-dihydroxyvitamin D formation in type I pseudohypoparathyroidism.

The role of parathyroid hormone (PTH) and cAMP in the hydroxylation of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D [1,25-(OH)2D] was explored in two young male volunteers and a patient with pseudohypoparathyroidism type I. Parathyroid extract infusion resulted in a prompt and distinct increase in the plasma levels of cAMP and the urinary excretion of the nucleotide in the normal controls, whereas there was only a negligible increase in the patient. In both the patient and the control subjects, the serum concentration of 1,25-(OH)2D showed a distinct increase after the parathyroid extract infusion. The responses were similar in magnitude and were apparent after 2 h, with a further rise 4 h in the patient and one of the controls, whereas the other control subject only responded after 4 h. The findings are consistent with the assumption that a normal renal cAMP response to PTH is not essential for the PTH stimulation of the renal 25-hydroxyvitamin D-1 alpha-hydroxylase. The two other dihydroxymetabolites of vitamin D, 24,25-(OH)2D and 25,26-(OH)2D, showed no consistent response to the PTH infusion in either the controls or the patient.

Adult↗

A familial syndrome of diaphyseal cortical thickening of the long bones, bowed legs, tendency to fracture and icthyosis.

The clinical and radiological features of a dominant bone disorder found in six members of the same family are described. The bone disorder was mainly characterized by endosteal cortical thickening of long tubular bones and bowing of the weight-bearing ones. The clinical symptoms were waddling gait, muscle weakness and leg pains, and there was a tendency to fractures. All affected individuals had icthyosis of slight or moderate degree.

Adult↗

Oral aspects of osteopetrosis.

The characteristic feature of osteopetrosis is a lack of osteoclastic activity, leading to a series of somatic problems for afflicted persons. The life span of osteopetrotic patients has increased in recent years, thereby making oral aspects of the disease more evident. Four children with malignant osteopetrosis, born between 1967 and 1975, were examined. In all patients the anterior teeth were of normal shape, and erupted on schedule. Primary molars and all permanent teeth were greatly distorted, and remained totally or partly embedded in basal bone. Vertical growth of alveolar ridge was very limited. Where a fenestration of overlaying mucosa had occurred, a localized progressive osteitis developed, leading to soft tissue inflammation and, in two cases, extraoral mandibular fistulas. Peridontal attachment was very poor, spontaneous exfoliation had occurred in all patients. In two children tooth germs and necrotic bone were surgically removed. No beneficial effect of the treatment was observed. Large doses of antibiotics were needed to control recurring infections. No means of curing progressive osseous destruction of mandibular bone has been found. The general prognosis is poor.

Child↗

Dental findings in patients with Aarskog syndrome.

Dental manifestations of the Aarskog syndrome were studied in 10 individuals. There was retarded development and eruption of the permanent teeth in six boys. Dental age was less retarded than height age and bone age. The prevalence of hypodontia and the prevalence and degree of orthodontic anomalies were higher than in the general population. Caries prevalence was high.

Abnormalities, Multiple↗

Acute response of parathyroid hormone in congenital osteopetrosis.

Indices of calcium and phosphorus metabolism were studied in 3 children with osteopetrosis before and after infusion of bovine parathyroid hormone extract. Basal plasma concentrations of calcium, alkaline phosphatase and 25-hydroxy vitamin D tended to be low. Plasma immunoreactive PTH levels were at the upper normal range in two patients. A marked increase in urinary cyclic AMP in all patients was solely due to an increase in the nephrogenous cAMP. After vitamin D treatment urinary cAMP was essentially unchanged with the same preponderance of nephrogenous cAMP. Following PTH infusion plasma cAMP showed a brisk rise. There was also a prompt rise in urinary cAMP and a distinct decrease in the calcium to sodium clearance ratio indicating increased calcium reabsorption. Phosphaturic effect was only observed when PTH was given in the highest dose level. The findings are consistent with a state of low grade hyperparathyroidism which could not be related to the plasma levels of 25-hydroxy vitamin D or calcium.

Child↗

Natural and immune antibodies to rabbit erythrocyte antigens.

Natural agglutinins to rabbit erythrocytes were found in all human sera studied. In the newborn, the antibodies were of IgG class; in the 6-month-old infants they were mainly of IgM class. Older children and adults had both IgG and IgM antibodies. Agglutinins to rabbit erythrocytes were also found in serum from fourteen of fifteen other species studied. The trichloroacetic acid extract from rabbit erythrocyte stromata (TCA-preparation) contains at least three different antigenic determinants: one which we hitherto to have found only on rabbit erythrocytes, one which is closely related to human blood group B antigen, and one which is closely related to the I antigen. The TCA-preparation did not elicit delayed hypersensitivity skin reactions in humans in spite of high titred agglutinins in serum, but did so in immunized guinea-pigs.

Adolescent↗

Lymphocyte multiplication in vitro induced by mitogens and antigens.

A simple technique requiring only 0.2 ml whole blood for measuring the response of lymphocytes in cultures to each of various mitogens and antigens has been elaborated. The response is quantified by comparing the number of lymphocytes with and without a stimulating agent. The increment of cell numbers is given by a cell multiplication index. In healthy subjects PHA induced almost a doubling of the cell numbers in 3 days, i.e. an index of 1.90 +/- 0.38. After 7 days the indexes for PHA, PWM and Con A were 7.25 +/- 4.12, 2.72 +/- 0.65 and 1.81 +/- 0.31, respectively. PPD and Candida-extract induced cell multiplication in skin positive individuals, with indexes ranging from 1.12 to 3.05. In contrast, patients with various severe immune deficiencies showed decreased responses to at least one mitogen, depending on the type of the deficiency. Likewise, skin test negative individuals had no or faint in vitro response to the antigens. The method, which correlated well with the response by a conventional method for incorporation of tritiated thymidine, has a high degree of precision and sensitivity, and should be applicable for routine use.

Adult↗

Alpha-1-antitrypsin (Pi)-types in recurrent miscarriages.

Chromosome analysis was carried out in a consecutive series of 57 couples with a history of recurrent miscarriage. All 114 subjects from these couples had normal karyotypes by conventional analysis. Pi typing was performed in 30 couples. The constellation of Pi heterozygosity in both partners occurred in two of the couples. The expected frequencies of the observed MS-MS and MS-MZ constellations occurring by chance would be 2.1 per 1,000 and 2.2 per 1,000 couples, respectively.

Abortion, Spontaneous↗