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Biomedical subjects

R E Johnsonbaugh

Publications and source records attributed to R E Johnsonbaugh.

17 recordsLinked to original sources
PubMed1979

The in vitro metabolism of progesterone, 4-androstene-3,17-dione, testosterone and 17 beta-hydroxy-5 alpha-androstan-3-one by fetal rhesus monkey testes.

Homogenates prepared from fetal rhesus monkey testes were incubated with progesterone, 4-androstene-3,17-dione, testosterone and 17 beta-hydroxy-5 alpha-androstan-3-one. The major progesterone metabolite was 17-hydroxy-4-pregnene-3,20-dione. Testosterone also accumulated in the progesterone incubations. 4-Androstene-3,17-dione was converted chiefly to testosterone. Testosterone was not actively metabolized by the fetal monkey testis. 17 beta-Hydroxy-5 alpha-androstan-3-one was actively converted primarily to 5 alpha-androstane-3 beta,17 beta-diol.

Androstenedione↗
PubMed1979

Dissociation of cortisol and adrenal androgen secretion in patients with secondary adrenal insufficiency.

Plasma cortisol, dehydroepiandrosterone (DHA), dehydroepiandrosterone sulfate (DHAS), and androstenedione (delta4-A) were measured by RIA during ACTH infusion in preadrenarchal children with constitutional short stature, normal adults, and patients with secondary adrenal insufficiency resulting from hypothalamic-pituitary disease or corticosteroid therapy. The plasma levels of all four steroids were decreased in patients with secondary adrenal insufficiency compared to normal adults, but the decrease in DHA and DHAS was considerably greater than that in cortisol and delta4-A, resulting in significant decreases in the plasma ratios of DHA to cortisol, DHAS to cortisol, DHA to delta4-A, and DHAS to delta4-A (P less than 0.00001). The decreased DHA and DHAS responses to ACTH persisted in one glucocorticoid-treated patient after glucocorticoid therapy was terminated and the cortisol response to ACTH had normalized. The data suggest that adrenal atrophy due to hypothalamic-pituitary disease or corticosteroid therapy is associated with a greater impairment in the secretion of the delta5 adrenal androgens DHA and DHAS than in the secretion of cortisol and delta4-A, and that the capacity to secrete cortisol and delta4-A recovers more rapidly than the capacity to secrete the delta5 adrenal androgens when corticosteroid therapy is withdrawn.

Adolescent↗
PubMed1979

Replacement oral ethinyloestradiol therapy for gonadal dysgenesis: growth and adrenal androgen studies.

We have studied growth and adrenal dehydroepiandrosterone (DHA) responses to iv synthetic adrenocorticotrophic hormone (ACTH, Cortrosyn) in 6 girls with gonadal dysgenesis before and during treatment with low-dose ethinyloestradiol (EOe2). In all patients there was a statisfactory induction of secondary sexual characteristics including increase in breasts and public hair and onset of withdrawal bleeding within 6 months of therapy. Height velocity increased from 2.8 +/- 0.9 cm/year pre-treatment to 5.3 +/- 1.5 cm/year (P less than 0.02) in the first year. There was deceleration to 1.9 +/- 1.1 cm/year in the second year. There was no disproportionate advancement in bone age and thus, presumably, no loss of ultimate height. We could demonstrate no change in basal or ACTH-stimulated levels of DHA, a specific adrenal androgen, to account for the increased public hair and growth in these patients.

Administration, Oral↗
PubMed1978

Exercise tolerance test. Single-sample screening technique to rule out growth-hormone deficiency.

Parent-directed vigorous exercise was evaluated as a screening test for adequacy of pituitary growth-hormone release in 57 short-statured children. This method obviated the need for pharmacologic provocative testing in all but the four children with growth-hormone deficiency. In 92% of the euendocrine children, the immediate postexercise venous sample demonstrated an adequate growth-hormone level. Vigorous physical exercise after an 8- to 12- hour fast with a single postexercise serum growth-hormone sample is a reliable, safe, and cost-effective screening test for growth-hormone deficiency.

Adolescent↗
PubMed1978

Premature craniosynostosis: A common complication of juvenile thyrotoxicosis.

Cranial vault suture opacification (apparent closure) and bone age were evaluated roentgenographically in ten children with thyrotoxicosis. The bone age was advanced greater than 2 SD in only one. In comparison to 96 control children of similar age, craniosynostosis was present in each of the patients with thyrotoxicosis. Children with advanced bone age, nine due to virilizing adrenal hyperplasia and three with precocious puberty, had normal radiographic patterns of cranial suture closure. Thyrotoxic premature craniosynostosis did not interfere with continued head circumference growth nor did it result in clinical or radiographic evidence of increased intracranial pressure. We conclude that premature craniosynostosis appears to be a common feature of juvenile thyrotoxicosis. Investigation of the possible long-term adverse effects of this entity on central nervous system function is advocated.

Adolescent↗
PubMed1977

Pseudogoiter.

Explore the source record for details and available documents.

Child, Preschool↗
PubMed1977

Somatomedin and growth hormone in the newborn.

Somatomedin (SM) levels were measured by porcine cartilage bioassay, and growth hormone (GH) levels by radioimmunoassay in 52 full-term umbilical cord plasma samples and 28 maternal plasma samples. The SM levels in cord plasmas was 0.50 +/- 0.19 units/ml (mean +/- SD) compared to an adult standard plasma pool of 1.0 units/ml. The cord GH levels were 41.7 +/- 36 mmicrogram/ml. The low relative value of SM in the cord plasma is consistent with that found during early childhood, and may reflect a lower level of requirement. The high neonatal GH levels are hypothesized to be a compensatory increase to overcome factors suppressing SM production in fetal life.

Adolescent↗
PubMed1977

Estrogen derivatives for the external localization of estrogen-dependent malignancy.

Four radioiodinated estrogen derivatives were studied to determine their affinity for the estrogen-binding protein found in the cytosol of rabbit and rat uteri. In vitro determination of the binding properties by competitive-binding experiments and by sucrose-gradient centrifugation indicates that one of the derivatives, iodohexestrol, binds to the cytosol estrogen-binding protein. This in vitro behavior was related to in vivo distribution. Studies in immature female rats showed high uterine uptake of iodohexestrol at 2 hr (1.69% dose/gm). Iodohexestrol also has a high nonspecific binding in both the blood and the uterine cytosol. Thyroxine can diminish the nonspecific binding in vitro; in vivo the prior injection of thyroxine increased the 2-hr uterus-to-blood ratio from 1.9 to 10.4 The in vitro receptor-assay system was helpful in predicting in vivo distribution.

Animals↗
PubMed1976

Physiological responses of men working in 25.5 degrees C water, breathing air or helium tri-mix.

Fourteen scuba divers in swim trunks did ergometer work while breathing air at 3 m in 25.5 degrees C water. They were stressed by work and cold. Exercise produced increases in heart rate, minute ventilation (VE), oxygen consumption (VO2), and catecholamine excretion. Cold lowered rectal temperature (Tre) despite exercise, and contributed to the increase in VO2 and catecholamine excretion. Immersion, cutaneous vasoconstriction, work, and scuba breathing contributed to a brisk diuresis, probably by centralizing blood volume and thus stimulating central vascular volume receptors. Similar exercise in 25.5 degrees C water, breathing helium tri-mix (gas density less than air), produced higher VE but lower VO2 when compared to air breathing. Tri-mix scuba breathing resulted in a smaller diuresis, perhaps because its lower density leads to lesser atrial distension during work. The fall in Tre during work in 25.5 degrees C water was identical whether air or helium tri-mix was respired, since helium does not accentuate respiratory convective heat transfer.

Adult↗
PubMed1975

Screening procedures for neuroblastoma: false-negative results.

Since elevation of 3-methoxy-4-hydroxymandelic acid (VMA) excretion frequently occurs in patients with neuroblastoma, simpler methods have been developed to differentiate between high and low levels of VMA in the urine, namely the LaBrosse spot test and VMA test strips. Sensitivity of these two procedures depends upon the concentration of VMA in the urine rather than total amount of VMA excreted. VMA excretion data from patients with neuroblastoma show that even though the total amount of VMA excreted in a 24-hour period may definitely be elevated, the concentration of VMA in the 24-hour urine samples may vary greatly from one day to the next and from one patient to another. Therefore, these rapid screening methods for urinary VMA would appear to be too insensitive to use as the sole means of detection or follow-up of patients with neuroblastoma since these techniques require a high concentration of VMA.

Child↗
PubMedDate not supplied

Plasma testosterone, luteinizing hormone and follicle-stimulating hormone one day after vasectomy.

Plasma testosterone, LH and FSH were measured in 20 healthy subjects prior to and one day after bilateral vasectomy. No significant change in these hormones was noted after surgery. These data suggest that the decrease in free testosterone index and FSH reported by others at one week post-vasectomy is probably not related to the effects of psychological stress, local anesthesia or surgical stress, either singularly or in concert. Further studies are indicated to evaluate the transient hormonal changes reported within the first few weeks following vasectomy.

Adult↗