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Biomedical subjects

H J Dean

Publications and source records attributed to H J Dean.

41 records · Page 3Linked to original sources

Comparative study of serum human growth hormone measurement with NB2 lymphoma cell bioassay, IM-9 receptor modulation assay, and radioimmunoassay in children with disorders of growth.

The biological activity of GH in serum from 10 adult volunteers, 6 children with normal stature, and 26 children with growth retardation was assessed using the Nb2 rat lymphoma cell bioassay and the IM-9 human lymphocyte receptor modulation assay. The bioassay/RIA ratios for both bioassays varied widely but the range of ratios found in the normal stature adults and children was not different than that found in the group of children with growth retardation, which included 4 children with a presumptive diagnosis of bioinactive GH. We conclude that the use of these two bioassays is a valid approach to the assessment of the bioactivity of the circulating molecular forms of GH and that a large number of children with disorders of growth can be screened to identify patients with bioinactive GH.

Adolescent↗

Diagnosis and natural history of 17-hydroxylase deficiency in a newborn male.

We documented 17-hydroxylase deficiency in a newborn male infant with micropenis, perineoscrotal hypospadias, and a bifid scrotum containing two histologically normal testes. Mild hypertension developed at 20 months of age. The diagnosis was made on the basis of elevated serum levels of progesterone (180-475 ng/dl), corticosterone (1.8-20.2 micrograms/dl), and desoxycorticosterone (56-330 ng/dl). There was an exaggerated response of these steroids to ACTH-(1-24) and suppression by dexamethasone. Mass spectrometric analysis of urinary steroids showed an abnormally high ratio of C21 to C19 3 beta-hydroxy-5-ene steroids due to reduced C19 steroid formation. We suggest that this infant has a form of 17-hydroxylase deficiency which is less severe than previously reported cases in view of his partial prenatal virilization, the minimal testosterone response to CG the absence of hypokalemia, and the presence of normal cortisol levels after prolonged ACTH stimulation. Family studies suggest reduced 17-hydroxylase activity in the father. A surprising coincident finding of no apparent clinical significance was in vitro evidence of 5 alpha-reductase deficiency in genital skin fibroblasts.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

The effect of growth hormone treatment on somatomedin levels in growth hormone-deficient children.

Serum levels of immunoreactive somatomedin (IRSM) and insulin-like activity (ILAs) by receptor assay have been measured in 177 GH-deficient (GHD) children treated with 2 U GH three times weekly for 6-10 months. The overall mean (+/- SD) pretreatment IRSM and ILAs levels were 0.21 +/- 0.30 and 0.39 +/- 0.25 U/ml, respectively. Pretreatment IRSM and ILAs levels were in the normal range for chronological age and sex in 15.8% and 33% of these GHD children. Mean IRSM and ILAs levels increased after 1 month of therapy to 0.36 +/- 0.51 and 0.62 +/- 0.33 U/ml, respectively (P less than .0001). The increase in serum IRSM levels (from 0.2 to 2.0 U/ml) that normally occurs from 1-16 yr of age is also evident in untreated GHD children, albeit to a lesser extent. In addition, the mean increase in IRSM after GH was greater in older patients. However, individual responses varied greatly. An increase in IRSM or ILAs with an increase in height velocity (HV) was observed in the majority of children, but all other combinations occurred, including increased SM with decreased HV, decreased SM with increased HV, and decreased SM with decreased HV. In summary 1) age-dependent factors in GHD children importantly influence basal and treatment SM leels; 2) a basal SM level is not a very sensitive diagnostic test, since a significant proportion of GHD children have SM levels in the normal range; and, 3) SM levels in individual patients may not increase with GH therapy and, thus, cannot be used to predict a clinical response to GH therapy.

Adolescent↗