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Biomedical subjects

R Steendijk

Publications and source records attributed to R Steendijk.

At least 37 records · Page 2Linked to original sources
PubMed1981

[Congenital functional disorders of the hypothalamus caused by a development disorder of the prosencephalon].

The case histories of three boys with a micropenis, abnormal facial features and congenital hypopituitarism are described. Two of the boys in addition had congenital deformities of the feet. A prolonged neonatal jaundice or a neonatal hepatitis, and an abnormal mental development was also found. This complicated syndrome is caused by impaired development of the prosencephalon. The ensuing anatomical changes have been called holoprosencephaly. Early recognition of this syndrome rests on the micropenis and the abnormal facial features.

Abnormalities, Multiple↗
PubMed1980

Hypophosphatemic vitamin D resistant rickets (phosphate diabetes): bone mineral problems studied by 125I-computed tomography and microradiography.

125I-computed tomography (CT) for the bone mineral analysis of the radius was performed on 9 children with vitamin D resistant hypophosphatemic rickets (VDRR) treated with vitamin D in pharmacological doses. Trabecular bone density was increased in 1 patient and normal in all others. The cortical width of the diaphysis of the radius was decreased, and the cross sectional area of the bone increased, but the total amount of compat bone mineral in the cross section was normal. Measurements of the second metacarpal bone on X-rays of the hand revealed similar findings. Microradiographic and histological examinations of the fibula on 9 different patients also treated with vitamin D showed grossly abnormal mineralization of bone tissue with a perilacunar mineral deficit. It is concluded, that the amount of compact bone and trabecular bone is not decreased in children with VDRR. The normal mineral content determined by CT and the impaired mineralization of the bone material examined by microradiography indicate an over-abundance of incompletely mineralized bone.

Adolescent↗
PubMed1980

Diagnostic and aetiologic features of idiopathic and symptomatic growth hormone deficiency in the Netherlands. A survey of 176 children.

In a survey of 176 children with hypopituitary growth failure symptomatic growth hormone deficiency (organic disease) was found in 25, whereas 151 children had idiopathic growth hormone deficiency. An isolated deficiency of growth hormone (IGHD) was found in 69 children of the latter group, 82 children had multiple pituitary hormone deficiency (MPHD). The sex ratio (boys/girls) in all idiopathic cases was 2.4. Familial occurrence was encountered in four families. This disorder did not occur more often in firstborn than in later-born children. Breech delivery was found in 37.1% of all idiopathic cases; it occurred more frequently in MPHD than in IGHD and in boys than in girls. 14% of 143 children with idiopathic growth hormone deficiency had a birthweight of 2500 g or less, which is more than the incidence in the country. The mean birthweight of children born at a gestational age of 38 weeks or more was normal. In view of the high incidence of breech delivery (presumably with associated birth injury) and the high familial occurrence, the aetiology in the majority of cases would be adequately described by a multifactioral mode of inheritance.

Adolescent↗
PubMed1979

Distribution of the perilacunar hypomineralized areas in cortical bone from patients with familial hypophosphatemic (vitamin D-resistant) rickets.

The perilacunar areas of low mineral density in microradiographs from cortical bone of patients with hypophosphatemic (vitamin D-resistant) rickets are not evenly distributed throughout the bone tissue. Their frequency and distribution were determined in bone from 9 patients with this disease. It was found that the lesion was more frequent in haversian bone than in interstitial bone, and along the inner circumference of growing haversian systems as compared with outer circumference. These findings indicate that the lesion is the result of retarded mineralization, and that mineralization slowly proceeds in these areas as the bone becomes older. A relatively high frequency of the lesion was also found in osteons with an elliptical cross section along the long axis of the ellipse. The cause of the abundance of the lesion at these sites is not clear, but it is possible to explain the uneven distribution in elliptical osteons by assuming an unequal rate of bone formation in these structures.

Adult↗
PubMed1975

The effect of a low-calcium diet in lactating rats; observations on the rapid development and repair of osteoporosis.

Female rats were given a low-calcium diet (0.05%) during the last three weeks of the lactating period, followed by a normal diet (1.03% calcium) during the first three weeks after lactation. The resulting bone loss and its recovery were studied by means of microradiography, tetracycline-uptake, quantitative estimation of the cortical area of cross-sections from the femoral midshaft, and estimation of total body calcium. The cortical area in the femoral midshaft fell to 46% of its original value during depletion, and then rose to 78% during the first three weeks after weaning. Total body calcium fell from 1.12% to 0.60% of body weight and then increased to 0.89%. Removal of bone occurred mainly in the spongiosa and on the endosteal side of the cortex. Subsequently, new bone was laid down on the endosteal side, but also to some extent on the periosteal side of the cortex. The mineral density of this new bone was low. During the recovery phase resorption cavities within the cortex were filled in a concentric manner as in Haversian remodeling. Neither this feature nor the low mineral density of bone are normally present in the rat.

Animals↗