Incidence of transient congenital hypothyroidism due to maternal thyrotropin receptor-blocking antibodies in over one million babies.

To determine the incidence of transient congenital hypothyroidism due to TSH receptor-blocking antibodies, we screened dried blood specimens obtained from 788 neonates identified as having possible congenital hypothyroidism (from a total population of 1,614,166 babies) and 121 controls. A RRA was used. The potency of blood spot TSH binding inhibitory activity was compared with the severity of congenital hypothyroidism to assess the possible etiological relationship. Maternal serum was studied to confirm the presence of blocking antibodies by both RRA and bioassay. Blood spots obtained from 9 infants contained potent TSH receptor-blocking activity. Samples from 2 additional babies, studied because of clinical suspicion of the disease, were also positive. Long term outcome was known in 8 of the 11 babies, and all had transient disease. Neonates with TSH receptor-blocking activity greater than 132 U/L had a significantly lower T4 level (P < 0.05) and higher TSH (P < 0.005) than those in whom TSH binding-inhibitory activity was less than 132 U/L. All 9 mothers had autoimmune thyroid disease, and 3 had more than 1 affected child. Potent blocking activity was present in 7 maternal serum samples as long as 7 yr after the births of their affected babies. We conclude that measurement of TSH binding-inhibitory activity in dried neonatal blood specimens is a simple and effective method to predict the occurrence of transient congenital hypothyroidism. The incidence of this disorder in North America is 1 in 180,000 normal infants, or approximately 2% of babies with congenital hypothyroidism.

Olfactory performance during childhood. II. Developing a discrimination task for children.

OBJECTIVES: (1) To create a match-to-sample odorant discrimination task (MODT) for children and adolescents; (2) to assess whether nonolfactory factors affect olfactory performance more on an identification task than on the MODT; (3) to evaluate subjects with olfactory dysfunction; and (4) to create age-appropriate sets of odorants for use in the MODT format to test children of different ages. STUDY DESIGN: We tested 75 normal children, aged 2 to 18 years, and 17 other subjects, aged 7 to 53 years, with known or suspected olfactory dysfunction, with the MODT. We compared the age trends in variability of scores on the MODT with those on an odorant identification task, using a weighted linear regression analysis. RESULTS: The MODT was useful in children aged 5 years and older, but not generally in the 2- to 4-year-old children. There was an appreciable age trend in the variability of the scores on the identification task but not on the MODT. Mean MODT scores for subjects with suspected or known olfactory dysfunction were far below average. Finally, we created four sets of odorants that will likely be sensitive to age-specific changes in olfactory performance. CONCLUSIONS: The MODT appears to be a suitable test instrument to assess olfaction in children aged 5 and older and is less likely to be influenced by nonolfactory factors than an identification task. According to our preliminary results, it is likely that the MODT will allow us to detect olfactory deficits in children of many ages.

Assessment of an abbreviated odorant identification task for children: a rapid screening device for schools and clinics.

To validate the level of olfactory performance of children, we tested 825 volunteers, aged 4-17 years, with an abbreviated form of our pediatric odorant identification task. The test consisted of sniffing and identifying five odorants (baby powder, bubble gum, candy cane, licorice and peach). Mean olfactory scores increased as a function of age, reaching a plateau of about 94-95% correct at 8 years of age. In general, girls out-performed boys. Physicians require a test instrument such as the one we have devised to allow them to diagnose olfactory dysfunction in children. The present task is particularly applicable in screening large numbers of children in clinics or schools because it can be administered easily and rapidly. Adult subjects with olfactory dysfunction also performed poorly on this odorant identification task designed for children. Therefore, we expect that our odorant identification task will also detect children with severe olfactory dysfunction.

Differential distribution of insulin-like growth factors and their binding proteins within bone: relationship to bone mineral density.

To evaluate the possibility that insulin-like growth factors (IGFs) and their binding proteins (BPs) in bone play a role in regulating cortical bone formation in growing animals, we compared changes in IGF and IGF BP levels with changes in bone mineral density (BMD) at three different regions (proximal, middle, and distal) along the rabbit femoral shaft. BMD measured by dual-energy x-ray absorptiometry decreased progressively from proximal to distal regions of the shaft, from 0.449 +/- 0.005 to 0.354 +/- 0.002 g/cm2 (mean +/- SEM; n = 9), respectively; total protein concentrations also decreased toward the distal region. We extracted the IGFs and their BPs from bone by demineralization in 10% EDTA and 4 M guanidine-HCl (pH 4.5). The IGFs were then separated from their BPs by size exclusion HPLC. The pH of the extraction buffer profoundly influenced the recoveries of the IGFs and, to a lesser extent, the total protein; at least 100% more IGFs were recovered at acid (4.5) pH than at neutral (7.5) or basic (10.5) pH. The levels of IGF-I decreased markedly from proximal to distal regions, from 273 +/- 27 to 100 +/- 38 ng human IGF-I equivalent/g bone (or 103 +/- 10 to 52 +/- 11 ng human IGF-I equivalent/mg protein), respectively. IGF-II was uniformly distributed (385 +/- 17 ng human IGF-II equivalent/g bone; mean of all three regions). Levels of the predominant 28-32 kD IGF BP doublet increased by about 100% from proximal to distal segments, regardless of whether the data were expressed per unit mass or protein.(ABSTRACT TRUNCATED AT 250 WORDS)

The differential regulation of insulin-like growth factor (IGF) binding proteins by IGF-I during the life span of the rat.

To evaluate the therapeutic potential of insulin-like growth factor-I (IGF-I) as an anabolic agent during aging, we determined its effects on IGF binding proteins (BPs) in male rats of 2, 8, 16, and 24 months of age. In control animals, a striking increase (143%) in the predominant 39-45 kDa serum IGFBP (BP-3), with little change in serum IGF-I, accompanied the marked deceleration of growth which occurred between 2 and 8 months; the levels of IGF-I and its BPs declined by 15% and 34%, respectively, later in life. Infusion of IGF-I (1.2 mg/kg/day) for 2 weeks produced progressively larger increases in circulating IGF-I with age, from 24% to 95% between 2 and 24 months, consistent with an age-related decrease in exogenous IGF-I clearance. We attributed these results to the large increase in IGFBPs that occurred with maturation, as well as an induction of IGFBP-3 (34-68%) and a larger increase in the 30-34 kDa IGFBP (BP-2; 136-235%) following IGF-I treatment in the older (16-24 months) animals. Anabolic actions of IGF-I, which were seen only in the older rats, included modes increases in weight velocity (5.2 +/- 1.2 g/week), serum phosphorous (20%), and alkaline phosphatase (26%) compared to age-matched controls. In conclusion, differential changes in the relative levels of the different IGFBPs with IGF-I treatment in older animals appeared to profoundly influence both the half-life and tissue accessibility of exogenous IGF-I, thus modulating the potential benefits of IGF-I as an anabolic agent during aging.

Dissociation of bone mineral density from age-related decreases in insulin-like growth factor-I and its binding proteins in the male rat.

We evaluated the possibility that age-related decreases in circulating and/or bone-associated insulin-like growth factor-I (IGF-I) and its binding proteins (BPs) were associated with the development of osteopenia in 8-, 16-, and 24-month-old specific pathogen-free Brown Norway/Fischer 344 male rats. We measured bone mineral densities (BMD) of femurs by dual-energy x-ray absorptiometry. IGFs and IGFBPs were extracted from bone and separated by molecular exclusion HPLC before quantitation by specific radioligand assays. BMD did not change significantly between 8 and 24 months of age. IGF-I levels decreased by about 30% between 8 and 24 months in both serum and bone. Similarly, both circulating and bone-derived IGFBPs also declined (30% and 60%, respectively) with age. Thus, maintenance of femoral BMD throughout most of the adult rat life span was dissociated from the age-related decline in circulating and bone-associated IGF-I and IGFBPs.

Subtle speech and motor deficits of children with congenital hypothyroid treated early.

This study surveyed the development and functioning of a group of 16 children with congenital hypothyroidism who had been followed closely since treatment was instituted at an average age of 15.6 days. This group of early-treated young children had no deficits in cognitive or adaptive functioning. Some isolated motor deficits were found, although results of the Finger-tapping and Marching subtests of the Reitan-Indiana battery did not replicate the New England Congenital Hypothyroid Collaborative (1985) finding of impaired performance. Speech deficits were documented in some. Congenitally hypothyroid children with delayed neonatal bone-age performed more poorly on most measures than those whose bone-age had been normal at birth.

Adrenal steroidogenesis in very low birth weight preterm infants.

Adrenal steroidogenesis was evaluated in 25 sick premature infants with a gestational age of less than 30 weeks. ACTH stimulation tests were performed on the fourth day of life using synthetic ACTH (36 micrograms/kg). Considering the stress and degree of illness, preterm newborns had low basal cortisol levels (mean +/- SEM, 207.4 +/- 23.5 nmol/L), and their levels were similar to basal levels reported for healthy full-term newborns (170.7 +/- 26.8 nmol/L; P = 0.31; reference data from Endocrine Sciences, Inc., Calabasas Hills, CA). However, compared to term neonates, preterm infants had markedly elevated basal levels of 17-hydroxypregnenolone (54.3 +/- 11.2 nmol/L), 17-hydroxyprogesterone (19.7 +/- 4.0 nmol/L), and 11-deoxycortisol (19.1 +/- 3.3 nmol/L), which were 7-, 18-, and 8-fold higher, respectively, than values for term infants. The activity of 3 beta-hydroxysteroid dehydrogenase was not significantly reduced in extremely premature neonates (mean basal ratio of 17-hydroxypregnenolone/17-hydroxyprogesterone, 2.9 +/- 0.2; ACTH-stimulated ratio, 6.5 +/- 0.4). In contrast, the mean basal substrate/product ratio of 11-deoxycortisol was markedly elevated in the preterm infants (11.9 +/- 2.2, ratio x 10(-2) compared to that in the full-term infants (2.1 +/- 0.4, ratio x 10(-2); P < 0.001). These findings are consistent with decreased activity of 11 beta-hydroxylase (11 beta OH) in preterm infants born at less than 30 weeks gestation. Decreased 11 beta OH activity appears to be more prominent than the deficiency of 3 beta-hydroxysteroid dehydrogenase that has been found in infants with lesser degrees of prematurity, suggesting that 11 beta OH activity may be regulated during fetal development to increase during the latter part of gestation.

Olfactory performance during childhood. I. Development of an odorant identification test for children.

Because there has been no suitable diagnostic instrument for evaluation of olfaction in children, we designed an odorant identification test for that purpose. We screened 40 microencapsulated odorants ("scratch 'n' sniff" cards) by randomly grouping them into 40 overlapping sets of five odorants each. Forty-one children, 4 and 5 years of age, tried to identify each test odorant, selecting their responses from among five photographs depicting the substances in the set of odorants. We used the results to select a subset of five odorants (baby powder, bubble gum, candy cane, fish, and orange). To determine how well these odorants could be identified by normal children, we tested another 134 subjects, 3 1/2 to 13 years of age. For children 3 1/2 years to 5 years 4 months of age, the mean (+/- SEM) percentage of correct responses increased from 66% +/- 8% to 92% +/- 2%. Thereafter the mean percentage of correct responses remained at a plateau of about 90%. The 10th percentile for the percentage of correct responses tended to be higher for girls than for boys throughout childhood. We concluded that this set of five odorants can be correctly identified by most normal children 5 years of age or older. The performances of three older subjects with Kallmann syndrome were all subnormal, but the overall efficacy of the test for evaluating children with olfactory deficits needs to be determined.

Ontogenesis of insulin processing in fetal rat hepatocytes.

We studied insulin processing and hepatic glycogenesis in cultured hepatocytes isolated from rat fetuses of 17, 19, and 21 days of gestation. Steady-state insulin binding increased by 250% between days 17 and 19, from 145 +/- 8 to 361 +/- 52 fmol/mg protein, and by an additional 40% (405 +/- 69 fmol/mg protein) by 21 days of gestation. At 37 degrees C, 125I-insulin was rapidly (t 1/2 less than 5 min) internalized by hepatocytes at all three ages, reaching maximal levels (63-76% of the total cell-associated radioactivity) by 15 min. 125I-labelled degradation products appeared rapidly (t 1/2 less than 15 min) within the cells. Yet, the majority (68-77%) of the intracellular radioactivity consisted of intact 125I-insulin, even after 4 h at 37 degrees C. Hepatocytes pre-loaded with 125I-insulin and then acid-stripped of surface-bound radioactivity, rapidly released both intact 125I-insulin (retroendocytosis) and its radiolabelled degradation products. While intact insulin was initially released more rapidly (t 1/2 less than 6 min), and reached a plateau after 15-30 min, the degradation products continued to accumulate in the medium for at least 4 h. Methylamine inhibited intracellular 125I-insulin degradation at all three gestational ages and also blocked insulin-stimulated glycogenesis in 19- and 21-day hepatocytes, without altering basal glycogen synthesis. Insulin-stimulated glycogenesis was not induced in 17-day fetal rat hepatocytes in control or methylamine-treated cultures. We conclude that both degradative and retroendocytotic pathways for processing insulin are present in fetal rat hepatocytes by 17 days of gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of age and IGF-I administration on elastin gene expression in rat aorta.

An age-related decrease in elasticity of arteries has been found in clinical and experimental studies done during the past two decades. We have investigated molecular and endocrine aspects of that decrease by examining the effects of age and insulin-like growth factor-I (IGF-I) on rat aorta elastogenesis. For comparison, pulmonary elastogenesis was examined in the same experimental animals. Different aged groups of male Fischer 344 rats (barrier protected) were implanted with minipumps for a two-week infusion of either 0.1 N acetic acid (vehicle solution) or IGF-I (1.2 mg/kg/day). The DNA content (micrograms DNA/g tissue) decreased with age in aorta but remained fairly constant in lung. Administration of IGF-I increased the aortic DNA content in all but the oldest rats. Conversely, the DNA content of pulmonary tissue was significantly increased in only the youngest animals. The steady-state levels of tropoelastin mRNA decreased dramatically in both aorta and lung with increased age. The decrease was greater in lung than aorta. Administration of IGF-I elevated aortic tropoelastin mRNA steady-state levels, whereas lung tropoelastin mRNA levels were unaffected by IGF-I administration. Aortic tissue synthesized decreased amounts of insoluble elastin with increased age. These results establish a direct relationship between aortic tropoelastin mRNA levels and the synthesis of insoluble elastin in aging. Administration of IGF-I increased aortic elastin synthesis throughout the life span of the rat, although the proportionate increase diminished with age.

Testosterone treatment in adolescent boys with constitutional delay in growth and development.

The administration of androgens to adolescent boys with constitutional delay in growth has been highly controversial because of the possibility of premature epiphyseal closure and reduced final height. We have treated 15 such boys with a mean (+/- SD) age of 14.1 +/- 1.0 years and a mean initial height of 142.2 +/- 8.6 cm (range, 127.1 to 156.2). The boys received monthly intramuscular injections of testosterone enanthate (50 mg) for 1.2 +/- 0.3 years. The mean height velocity rose from the 3rd percentile for mean skeletal age to above the 90th percentile, where it remained throughout treatment. Although skeletal maturation accelerated initially in the seven boys with a skeletal age under the pretreatment group mean of 11.3 years, it advanced normally in the others. The concomitant increase in stature was sufficient to offset the advancement in skeletal age in most boys, so that the mean predicted adult height was essentially unaffected. Sexual maturation also progressed; testicular volume increased from 5.9 +/- 2.7 to 11.3 +/- 2.7 ml. After treatment, the skeletal age advanced normally and sexual development continued. Eight of the boys are now 18.1 +/- 0.5 years of age and have stopped growing; their present mean height (167.6 +/- 4.7 cm) is very close to their pretreatment predicted height of 168.0 +/- 5.6 cm. We conclude that low-dose testosterone treatment is effective in adolescent boys with delayed growth and development and that it does not appear to compromise final adult height.

Olfactory deficits in boys with cleft palate.

An odor identification task was used to determine whether individuals with cleft palate (with or without cleft lip) also have an increased prevalence of olfactory deficits. Olfactory responses of 35 affected subjects (7 to 22 years of age) were compared with those of 68 subjects of comparable age without cleft palates. Subjects were requested to identify the smell of ten common household odors. They selected their responses from an alphabetized list of the test odorants. After a practice trial, the set of odorants was presented five times in randomized sequences. The percentage of correct responses increased with age for prepubertal and pubertal subjects without cleft palates. Although the olfactory scores of girls without cleft palates continued to increase after puberty, this trend was absent in boys. On the average, the girls with cleft palates, compared with only three of 34 boys without cleft palates, had olfactory scores less than 60% correct. There was no evidence of heterogeneity in the magnitude or direction of the relationship between any of the subtypes of cleft palate and olfactory dysfunction. In this study, cleft palate is more strongly associated with olfactory deficits in boys than in girls, suggesting the possibility that the deficit may be a sex-influenced trait.

Effect of growth hormone on growth and glucose tolerance of normal rats.

To determine the effect of growth hormone (GH) administration on growth rate, ultimate size, and glucose tolerance of intact rats, we administered ovine GH to male Sprague-Dawley weanling rats for six weeks. Growth hormone, in a dose sufficient to double the growth rate and increase sixfold the somatomedin C (SM-C) levels of hypophysectomized rats, failed to increase the rate of growth or size of visceral organs of intact rats. Their SM-C levels increased only 10%. Following glucose administration, the mean blood glucose levels were higher at every time point measured in those treated with GH compared with the intact control animals. We conclude that, although there was no difference in somatic or visceral growth, the dose of exogenous GH administered increased SM-C levels and decreased glucose tolerance in the intact rats. While a larger GH dose might increase the final body size of non-GH-deficient animals, impaired glucose tolerance could be a significant side effect.

Hormonal regulation of somatomedin secretion by fetal rat hepatocytes in primary culture.

To determine which hormones might regulate somatomedin secretion in the fetus, we measured somatomedin levels in conditioned medium from primary cultures of fetal rat hepatocytes. We employed a bioassay [( 3H]thymidine incorporation into DNA of chick embryo fibroblasts), a displacement assay [competition for binding of radiolabeled multiplication-stimulating activity (rat insulin-like growth factor II) to the somatomedin-binding protein] for total somatomedin, and the RIA for somatomedin-C. Epidermal growth factor and dexamethasone were the most active hormones tested; total somatomedin levels were 2-3 times above control levels. Rat GH was much less stimulatory. Human placental lactogen, glucagon, and insulin had little or no effect. Stimulation of somatomedin secretion by both epidermal growth factor and dexamethasone was time and dose dependent. The maximal response occurred at 48 h at a concentration of about 1 X 10(-7) M of either hormone. In the bioassay, stimulation by epidermal growth factor, but not dexamethasone, was detected. The steroid enhanced the secretion of an inhibitor that completely masked the mitogenic activity of the increased somatomedin levels. The somatomedin secreted by fetal hepatocytes exhibited immunological cross-reactivity with human somatomedin-C, but the levels were 500-fold less than those measured by our displacement assay. This suggests that the predominant fetal rat somatomedin is not somatomedin-C. We conclude that epidermal growth factor and dexamethasone, but not GH or placental lactogen, stimulated the secretion by fetal hepatocytes of a somatomedin which resembled multiplication-stimulating activity.

The influence of epidermal growth factor on surface morphology of fetal rat hepatocytes in primary culture.

In an attempt to understand the hormonal regulation of somatomedin secretion in the fetus, we have confirmed that epidermal growth factor (EGF) stimulates fetal rat hepatocytes in primary culture to secrete somatomedin in a time and a dose-dependent fashion. Transmission electron microscopy (TEM) revealed that the cultured cells had ultrastructural features consistent with those of fetal hepatocytes. Scanning electron microscopy (SEM) showed that cells grown in either Medium 199 or EGF supplemented Medium 199 formed cellular aggregates within 6 h. The surface features of cells in control and experimental cultures were indistinguishable up until 24 h after exposure to EGF. At this point in time, morphological differences between treatment groups were first apparent with SEM. In the presence of EGF, cellular aggregates were thicker, cells were more rounded in contour, and the number of microvilli and cytoplasmic excrescences (blebs) was greater than in control cultures. These differences were further accentuated at 48 h after exposure to the growth factor. Since the appearance of microvilli and blebs coincides with increasing production of somatomedin, they may represent morphological evidence of secretory activity.

Parathyroid hormone infusion test in children and adolescents.

10 children with short stature were infused with parathyroid hormone (PTH). The results were compared to those obtained from a study of 28 normal adult volunteers. As expected, the children had higher basal serum phosphorus levels than the adults. PTH administration increased urinary excretion of cyclic AMP, sodium, potassium, bicarbonate, phosphate clearance, and reabsorption of calcium. The responses of the children were indistinguishable from those of the adults. Infusion of PTH to 3 children with hypoparathyroidism produced exaggerated cyclic AMP, phosphate, calcium, potassium, and bicarbonate responses. When given to a patient with pseudohypoparathyroidism, it did not increase urinary excretion of cyclic AMP and potassium or phosphate clearance, but did induce normal sodium and bicarbonate excretion. We conclude that the values obtained from normal adults are applicable to children and are useful in the evaluation of hypocalcemia in childhood.

Desmopressin response of enuretic children. Effects of age and frequency of enuresis.

To characterize the children with enuresis likely to respond to desmopressin acetate, we performed a double-blind crossover study that included the use of a placebo. During the two weeks of desmopressin administration, six children (12%) had 13 or 14 dry nights, and 15 children (29%) had eight to 12 dry nights. Among the 17 children aged 9 years or older, with four to seven dry nights during the two-week baseline period, 12 children (71%) responded to desmopressin (eight to 14 dry nights). In contrast, none of the 15 children younger than 9 years of age with fewer than three dry nights before therapy responded. During the posttreatment period, only four of the 21 drug responders reported a persistent effect. Desmopressin may be effective in reducing the frequency of enuresis, especially in children older than 9 years of age without nightly enuresis.

Altered osmotic threshold for vasopressin release and impaired thirst sensation: additional abnormalities in Kallmann's syndrome.

Seven subjects with Kallmann's syndrome were studied to determine whether they had disturbances of fluid homeostasis. Simultaneous measurements of urine and plasma osmolality (Uosm and Posm, respectively) were made during free access to fluids. The Uosm-Posm relationship was abnormal in five patients on at least one occasion. Patient 2 was frequently overhydrated (Posm less than or equal to 280 mosmol/kg) and patient 5 excreted a dilute urine when his Posm was 290 mosmol/kg. The three subjects (1, 5, and 7) tending to have an increased Psom (greater than or equal to 300 mosmol/kg) were able to concentrate their urine (Uosm greater than 800 mosmol/kg) and denied polyuria and polydipsia. Their elevated Posms could be explained by impairment of thirst, rather than increased excretion of water, because the patients concentrated their urines at normal Posms during fluid deprivation. The osmotic threshold for vasopressin release was decreased (Posm = 270.6 mosmol/kg) in one patient and increased (Posm greater than or equal to 295 mosmol/kg) in two others of the seven patients. The elevated osmotic threshold was not due to chronic hyperosmolality or a generalized defect in vasopressin secretion. In the patient with the highest osmotic threshold (Posm = 296 mosmol/kg) and Posms between 289--301 mosmol/kg during free access to fluid, the osmotic threshold decreased to only 293 mosmol/kg after 6 weeks of adequate hydration and desmopressin acetate. However, in response to hypotension induced by trimethaphan, he increased his plasma vasopressin from 1--26 microU/ml. In conclusion, some patients with Kallmann's syndrome may have osmoreceptor dysfunction and abnormal thirst regulation, indicating more extensive hypothalamic involvement than previously appreciated.