Growth hormone receptor deficiency in Ecuador: clinical and biochemical phenotype in two populations.

We have identified 56 patients with GH receptor deficiency (Laron syndrome) from two provinces in southern Ecuador, one group of 26 (Loja province) with a 4:1 female predominance and 30 patients from neighboring El Oro province with a normal sex ratio. There were no significant differences between the Loja and El Oro populations in stature (-5.3 to -11.5 standard deviation score), other auxologic measures, or in biochemical measures. GH binding protein, the circulating extracellular domain of the GH receptor, was measured by ligand immunofunction assay and found to be comparably low in children and adults. Levels of insulin-like growth factor (IGF)-I and -II and the GH-dependent IGF binding protein-3 (measured by RIA) were significantly greater, and GH and IGF binding protein-2 levels significantly lower in adults than children. Levels of IGF-I (adults) and IGF binding protein-3 (children and adults) correlated inversely with statural deviation from normal (P < 0.01). School performance was at an exceptionally high level, 41 out of 47 who had attended school being in the top 3 in classes of 15-50 persons.

Hormonal and metabolic effects and pharmacokinetics of recombinant insulin-like growth factor-I in growth hormone receptor deficiency/Laron syndrome.

Profound growth failure despite elevated GH levels in GH receptor deficiency (GHRD) results from reduced insulin-like growth factor-I (IGF-I) synthesis. Recent reports of improved growth velocity in children with GHRD during IGF-I therapy indicate growth-promoting potential in humans. We evaluated the pharmacokinetics and metabolic/hormonal effects of recombinant human IGF-I (40 micrograms/kg every 12 h) given sc for 7 days to six adults with GHRD. Hypoglycemia (< 2.5 mmol/L) did not occur, and mean 2 h postprandial insulin levels were reduced. Urinary calcium increased 2-fold (P < 0.01), and serum calcium was unchanged. The mean integrated 24-h GH level was suppressed (6.5 +/- 2.1 to 1 +/- 0.2 micrograms/L), as were the number of peaks, area under the curve, and clonidine-stimulated GH release (all P < 0.05). The mean pretreatment IGF-I level (36 +/- 2 micrograms/L) was 19% of the Ecuadorian control value (190 +/- 15 micrograms/L), it achieved a peak (253 +/- 11 micrograms/L) between 2-6 h after IGF-I injection, and at 12 h it was 137 +/- 8 micrograms/L. There were no significant changes in the half-life (8.2 +/- 1.5 to 9.7 +/- 1.9 h) or metabolic clearance (0.35 +/- 0.1 to 0.24 +/- 0.05 mL/kg.min) between days 1 and 7; however, distribution volume increased (183 +/- 10 to 266 +/- 36 mL/kg; P < 0.03). Baseline IGF-II levels were 47% of the control value and decreased during IGF-I therapy (273 +/- 10 to 178 +/- 9 micrograms/L; P < 0.01), correlating inversely with IGF-I levels (r = -0.3; P < 0.001). Although IGF-binding protein-3 (IGFBP-3) levels were not significantly influenced, baseline IGFBP-2 levels (153% of the control) increased 45% (P < 0.01). We conclude that IGF-I (40 micrograms/kg every 12 h) given sc to adults with GHRD is safe; achieves normal levels of IGF-I; reduces insulin, IGF-II, and GH levels; and increases IGFBP-2 concentrations and urinary excretion of calcium.

A randomized, double blind, placebo-controlled trial on safety and efficacy of recombinant human insulin-like growth factor-I in children with growth hormone receptor deficiency.

GH insensitivity due to GH receptor deficiency is a rare autosomal recessive condition, characterized by deletions or mutations of the GH receptor gene. Patients are refractory to both endogenous and exogenous GH, resulting in severe growth retardation. Therapy with recombinant human insulin-like growth factor-I (rhIGF-I) can bypass the defect in the GH receptor and potentially stimulate growth. We previously identified a genetically homogeneous group of patients in southern Ecuador, thus providing a patient base for a controlled clinical trial of rhIGF-I therapy. Seventeen prepubertal patients were entered in a randomized, double blind, placebo-controlled trial. Subjects received either a 12-month course of rhIGF-I (120 micrograms/kg, sc, daily) or 6 months of placebo followed by 6 months of rhIGF-I. Subjects receiving rhIGF-I showed a significant increase in growth rate, which was sustained over the 1-yr course of therapy (from 2.9 +/- 0.6 to 8.6 +/- 0.4 cm/yr). Incidents of hypoglycemia were equal in frequency in the placebo and rhIGF-I groups. One recipient of rhIGF-I developed papilledema, which resolved spontaneously. rhIGF-I therapy did not alter serum IGF-binding protein-3 concentrations. rhIGF-I treatment is effective in stimulating skeletal growth in GH receptor deficiency. Although the therapy proved to be safe, the potent metabolic actions of rhIGF-I and the persistently low levels of serum IGF carrier protein necessitate continued careful observation for side-effects.

The composition and distribution of insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) in the serum of growth hormone receptor-deficient patients: effects of IGF-I therapy on IGFBP-3.

We have previously reported that adult GH receptor-deficient (GHRD) patients treated subcutaneously with recombinant human insulin-like growth factor (IGF)-I have increased serum IGF-I levels and decreased IGF-II levels, whereas IGF-binding protein-3 (IGFBP-3) levels were unchanged. To further investigate the effects of IGF-I administration upon the IGF-IGFBP axis in GHRD, we have examined: 1) the molecular distribution of IGF-I and IGF-II among the IGFBPs; 2) the composition and distribution of the IGFBPs, in particular IGFBP-3; and 3) the acid labile subunit (ALS). Serum samples from adult GHRD patients who were treated sc with recombinant human IGF-I (40 micrograms/kg, sc, twice a day) or from normal Ecuadorian adults were incubated with [125I]IGF-II and subjected to neutral size-exclusion chromatography. The fractions were then subjected to Western ligand blot, Western immunoblot, IGFBP-3 RIA, and IGF RIAs. Serum of healthy adults incorporated [125I]IGF-II into the 150- and 44-kilodalton (kDa) IGFBP region. The 150-kDa IGFBP region contained most of the circulating IGFBP-3, whereas the 44-kDa IGFBP region contained mainly IGFBP-1, 2, and 4. The 150-kDa region also contained a unique 28-kDa immunoreactive form of IGFBP-3, which was not detectable by Western ligand blot. Endogenous IGF-I and IGF-II were distributed equally in the 150- and 44-kDa IGFBP regions. Sera from GHRD patients mainly incorporated [125I]IGF-II into the 44-kDa IGFBP region. Similar to control sera, the 150-kDa IGFBP region contained IGFBP-3, albeit at lower concentrations. The 44-kDa IGFBP region contained all IGFBPs including 50% of the total immunoreactive IGFBP-3. The two immunoreactive forms of IGFBP 3 (40- to 45-kDa doublet and 28-kDa band) were present in both IGFBP regions. The IGF size-distribution study revealed that the 150-kDa IGFBP region carried half of the circulating endogenous IGF-I, but only 30% of the IGF-II. Concentrations of the ALS were consistently low. Administration of IGF-I to GHRD patients was unable to increase concentrations of the molecular forms of IGFBP-3, correct the aberrant distribution of IGFs among the IGFBPs, or increase serum concentrations of ALS. In conclusion, we have found two forms of IGFBP-3 associated with IGF and ALS, which are capable of forming the ternary 150-kDa complex in healthy adult serum. The ratio of these two forms of IGFBP-3 and their distribution in serum was different between GHRD and control patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Anticholinergic exacerbation of phenothiazine-induced extrapyramidal syndrome.

The authors used tremography to record the bilateral digital tremor of a patient showing extrapyramidal system effects in response to withdrawal from phenothiazines. They found that changes in the amplitude of tremor correlated with clinical ratings of extrapyramidal disturbance. Changes in the amplitude and in the spectrum of tremor were similar to the bipolar paradoxical changes seen during intoxication with an anticholinergic psychotogen.

Paradoxical reaction to L-dopa in schizophrenic patients.

The authors administered 6 g of L-dopa to 8 schizophrenic patients and 750 mg of chlorpromazine to 7 schizophrenic patients. Chlorpromazine showed only a modest advantage over L-dopa and only on some Brief Psychiatric Rating Scale factor scores, and at maximum dosage the thought disturbance factor score in the L-dopa-treated group was not worse than at baseline. The results suggest that L-dopa is associated more with toxic than with schizophreniform symptoms and that there is adaptation to its effects. The authors discuss implications of these findings for the dopamine hypothesis of schizophrenia.

Disorders of calcium and phosphorus metabolism in adolescents.

During adolescence, there are marked changes in the metabolism of calcium and phosphorus and a dramatic increase in the rate of bone mineralization under the influence of the sex hormones, growth hormone, and insulin-like growth factor-1. More than 50% of adult bone mass is accumulated during puberty; failure to achieve maximum bone mineralization at this time may lead to osteopenia and its complications in later adulthood. This article discusses the causes, evaluation, and management of adolescents with hypocalcemia, hypercalcemia, and disorders of bone mineralization.

The role of serial sampling in the diagnosis of growth hormone deficiency.

We analyzed 12-hour serial sampling of growth hormone (GH) levels in two cohorts of short children: 96 children referred to a university endocrine clinic or studied on a research protocol and 825 children in the National Cooperative Growth Study of children treated with exogenous GH. The mean 12-hour GH levels correlated with growth velocity in 60 children with normal height and growth velocity in the university study, and this correlation was stronger in the boys. The testosterone levels also correlated with growth velocity and mean 12-hour GH levels in the boys. The mean 12-hour GH levels were lower in a group of 36 children with idiopathic short stature than in the control subjects, as were the peak GH levels within 1 hour after the onset of sleep and the insulin-like growth factor I levels. In the National Cooperative Growth Study cohort, pooled 12-hour GH levels were lower in the group with idiopathic GH deficiency (n = 300) than in the group with idiopathic short stature (n = 525), but the difference was not significant. The duration of GH treatment was the most significant predictor of change in the height SD score in both groups. Indices of spontaneous secretion of GH were not predictive of the response to GH treatment, nor were the results of provocative GH testing, the responses to GH treatment being similar in both groups over time. We conclude that the results of GH testing must be interpreted for each patient and that several testing modalities may be helpful in finding GH insufficiency that originates at various levels of the somatotropic axis.

Simultaneous analysis of 14 non-steroidal anti-inflammatory drugs in human serum by electrospray ionization-tandem mass spectrometry without chromatography.

A method is described for the simultaneous analysis of 14 non-steroidal anti-inflammatory drugs (NSAIDS) in human serum using negative electrospray ionization-tandem mass spectrometry (ESI-MS/MS). After addition of internal standard and protein precipitation using acetonitrile, samples were transferred to autosampler vials for direct analysis without chromatography. Injection of an air bubble with the sample and a multiple reaction monitoring (MRM) method using argon collision-induced dissociation (CID) of analyte (M-H)- ions permitted integration of the product ion peak areas to produce reproducible quantitative data over the range of concentrations expected in serum during routine use of these drugs. The method permitted the analysis of 30 samples per hour. Two hundred fifty consecutive analyses did not adversely affect instrument sensitivity.

Stillbirth after nonstress testing.

The authors' experience with stillbirth within one week of a reactive nonstress test was reviewed to determine the reliability of this test in postdates patients and general high-risk patients. The corrected stillbirth rates were the same in both groups. Thirty-three percent of stillbirths in postdates patients occurred as early as 41.5 weeks' gestation. The cause of stillbirth in postdates patients was not clear even after careful autopsy. In the general high-risk group, 60% of stillbirths were due to an acute event with the remainder due to chronic fetal compromise that was not predicted by the nonstress test. Induction at 41.5 weeks' gestation or more comprehensive fetal surveillance than weekly nonstress testing are possible approaches to the management of postdates pregnancy, which need to be further studied.

Long-term effects of minoxidil in the treatment of malignant hypertension in chronic renal failure.

Thirteen acutely symptomatic malignant hypertensive patients were treated with minoxidil in combination with a beta-adrenergic blocking agent and diuretics or dialysis. The degree of endorgan involvement varied, with the kidney being the most compromised in 11 of 13 patients. In 12 of 13 patients, MABP (mean arterial blood pressure) fell significantly within 72 hours, P less than 0.005. After 20 months of therapy, all have now had a favorable response, with a mean reduction in MABP of 48 mm Hg, and with no adverse cardiac disturbances. In addition, the patients with mild azotemia had an improvement in renal function as determined by a reduction in serum creatinine. PRA (peripheral renin activity) rose with the addition of minoxidil despite therapeutic concentration of serum propranolol and a reduction in MABP and heart rate. It was also noted that those patients who had been on guanethidine prior to minoxidil had a more pronounced lowering of MABP within 72 hours of minoxidil therapy. It is concluded that minoxidil is a safe, fast, and effective agent to achieve rapid and sustained control of MABP in malignant hypertensive states associated with chronic renal insufficiency.

Spectrum of serum thyroglobulin elevation in congenital thyroid disorders.

Serum thyroglobulin (Tg) data are presented for 47 infants with congenital thyroid disorders. Abnormal elevation of serum Tg (> 250 micrograms/L) occurred in 17% of the population studied, whereas values in excess of 1,000 micrograms/L were demonstrated in 11% of infants. The latter group includes the first report of supraphysiologic Tg elevation in an infant with thyroid gland ectopia, and the highest reported thyroglobulin level in the syndrome of generalized thyroid hormone resistance in an infant homozygous for a novel deletion in the c-erbA beta receptor. Mechanisms involved in the pathogenesis of Tg elevation are discussed. We conclude that Tg elevation in congenital thyroid disorders is more common than previously recognized, and values > 1,000 micrograms/L identify infants with a spectrum of anatomic and biochemical abnormalities.

Autoimmune hyperthyroidism in prepubertal children and adolescents: comparison of clinical and biochemical features at diagnosis and responses to medical therapy.

We explored our clinical impression that young children with autoimmune hyperthyroidism are more thyrotoxic at presentation and require a longer course of medical therapy than do adolescents to achieve remission. A retrospective chart review of clinical and biochemical data at presentation and response to therapy in 32 prepubertal (PREPUB) and 68 pubertal (PUB) children and adolescents with autoimmune hyperthyroidism was undertaken. Initial therapy included prophylthiouracil or methimazole in all but 11 patients who chose radioactive iodine (131I); 30 additional patients ultimately chose 131I or surgery after an initial period of medical therapy. In PREPUB children there were significantly longer duration of symptoms (7.8+/-7.7 months) and higher serum concentrations of triiodothyronine (T3) 708+/-330 ng/dL) at presentation than in the PUB group (4.7+/-3.4 months; p < .05) (537+/-197 ng/dL; p < .01). Duration of symptoms correlated negatively with chronologic age (r = -0.24; p < .02) but not with T3 or thyroxine (T4) levels (p = .1). PUB children had significantly higher titers of thyroid microsomal antibodies (positive dilution factor 1:6022+/-14572) than did PREPUB children (1:592+/-1226; p < .05). There was a higher familial incidence of thyroid disease in boys (80%) than in girls (64%) (p < .02). The duration of medical therapy was significantly longer (3.5+/-2.9 years) in PREPUB children compared to the PUB group (2.2+/-1.8 years) (p < .05). Only 17% of PREPUB treated 5.9+/-2.8 years compared with 30% of PUB treated 2.8+/-1.1 years achieved a 1-year remission after stopping antithyroid medication (percentage between groups, p < .01; years of treatment, p < .05). The median time to remission after medical therapy was 8 years in PREPUB and 4 years in PUB (p < .02). PREPUB children continued to remit after prolonged medical therapy (>6 years) whereas PUB patients did not. Total treatment length correlated negatively with chronological age (r = -0.26; p < .05) and positively with T4 and T3 concentrations at diagnosis (r = 0.31; p < .01). The diagnosis of hyperthyroidism is delayed in prepubertal children compared to adolescents. This delay may contribute to the higher T3 levels observed in this group at presentation. Prepubertal children also appear to require longer medical therapy to achieve a lower rate of remission, but do continue to remit after prolonged treatment. These differences in response to therapy should be considered when discussing therapeutic options with the family.

Hetero- and isosexual pseudoprecocity associated with testicular sex-cord tumors in an 8 year-old male.

Enlargement of the right breast, axillary hair, and acceleration of linear growth rate were first noted at 8 years of age in an otherwise healthy male with no known exposure to exogenous hormones. At 9.5 years of age the right subareolar mass was excised; histologic examination revealed fibrous breast tissue. Subsequently pubic hair appeared. At 10.7 years of age, the patient complained of right inguinal pain after a minor injury. Examination revealed a tall (height age 12.7 years), mature, muscular boy with enlarged (R: 5 x 3 x 2 cm; L: 3 x 2 x 3 cm) firm, irregular testes, Tanner stage II pubic hair, and modest axillary hair. No perioral pigmentation was present. Testicular ultrasonography revealed multilobular echogenic foci with calcifications. Bone age was 13 years, the LH and FSH secretory responses to GnRH were minimal (LH: < 0.038-->0.28 mIU/ml; FSH: < 0.063-->0.11 mIU/ml), and basal serum testosterone (< 10 ng/dl) and estradiol (< 10 pg/ml) values were undetectable. Following administration of human chorionic gonadotropin (hCG), the serum testosterone concentration increased to 275 ng/dl, while estradiol remained unmeasurable. Spermatic vein concentrations of testosterone were undetectable in the basal state and increased after hCG administration. After bilateral orchiectomy, pathologic examination revealed multifocal tumors composed of brightly eosinophilic, large polygonal cells arranged in nests, cords, and clusters within dense connective tissue or mucinous stroma with lamellar calcifications of varying sizes. These pathologic findings were compatible with a large cell calcifying Sertoli cell (sex-cord)tumor of the testes. Testosterone, estradiol, immunoreactive and bioactive aromatase activity were not detectable in the tumor. Thus, both heterosexual (gynecomastia) and isosexual (increased musculature, pubic and axillary hair) precocious puberty may occur in boys with testicular sex-cord tumors.

Leptin binding activity (LBA) in plasma of nondiabetic and diabetic adolescents and obese children: relation to auxologic and hormonal data.

Leptin circulates in serum bound to high molecular weight proteins. Hypothesizing that leptin binding proteins may regulate the functional efficiency of leptin, we characterized auxologic and hormonal factors that influence leptin binding in three disparate groups: normal adolescents, obese children, and teenagers with type I diabetes mellitus (IDDM). Specific leptin binding activity (sLBA) was assessed by column chromatography after incubation of serum with 125I-leptin in the presence and absence of excess unlabeled leptin. Mean sLBA was 17.0 +/- 7% (SD) in the healthy adolescents (n=41), 6.6 +/-4.3% in the obese children (n=26), and 14.9 +/-7.3% in the diabetic teenagers (n=17). At any value of sLBA, obese children had higher serum leptin levels than non-obese adolescents or diabetic teenagers, consistent with "leptin resistance" in the obese group. sLBA was higher in males than in females only in those with diabetes (18.6 +/- 7.3 vs 10.9 +/- 5.1%, p<0.05). sLBA correlated inversely with serum insulin-like growth factor-I values in the normal group (r= -0.45, p<0.01) and with insulin in the obese children (r= -0.53, p<0.01). There was no correlation between sLBA or serum leptin values and HbA1c, in the diabetic group. The serum leptin concentration was the principal determinant explaining the total variability of sLBA in all three cohorts. However, body mass index (BMI = weight/ height2) accounted for more of the total variability of percent specific binding in the healthy adolescents than in the other groups. We conclude that sLBA reflects circulating leptin levels, body composition, and hormonal milieu. Thus, in addition to leptin, qualitative and quantitative characteristics of leptin binding may play a physiological role in the regulation of appetite and in the "leptin resistance" of obesity.

Extraction of benzoylecgonine (cocaine metabolite) and opiates (codeine and morphine) from urine samples using the Zymark RapidTrace.

The Zymark RapidTrace automated solid-phase extraction system has been evaluated for use in the urine drug-testing laboratory. Methods for cocaine metabolite (benzoylecgonine) and opiates (codeine and morphine) are described and evaluated. The linearity, precision, accuracy, recovery, and carryover statistics of these analytical protocols are presented. The advantages of extraction using the RapidTrace instead of solid-phase extraction with the manual vacuum manifold or liquid-liquid extraction methods are described.

Patients' prenatal medical record précis.

A prenatal assessment form for ambulatory prenatal patients was designed to provide information required for effective patient care during unscheduled visits or for visits with health-care providers unfamiliar with a patient's history. The abbreviated record enables health-care providers to manage problems before obtaining complete medical records from centralized sources. In two years of use, these abbreviated records have improved both the efficiency and quality of care for unscheduled and scheduled visits.

Height screening in the community. The commercialization of growth. The role of the pediatrician.

The availability of unlimited but costly supplies of biosynthetic growth hormone has led to pressure for pharmacologic use (as opposed to replacement therapy in proven deficiency states). Commercial and altruistic motives have converged to promote community height screening among individuals who have been perceived by themselves or parents as short. This does not meet accepted criteria for health screening. Height screening of large populations of children yields few unrecognized medical conditions. If the goal of community screening is to identify abnormally short individuals (less than 3%) who might benefit from growth hormone treatment and if the unproven assumption is correct that stature correlates with success and happiness, then those less likely to appear for screening need to be recruited to avoid elitist domination. The annual cost of such growth promotion would be greater than $10 billion, with no evidence for substantial health benefits. Growth monitoring of all children through improved height measurement in schools and in physicians offices, as part of health supervision, is a more sound community approach than height screening.

Automated extraction of lysergic acid diethylamide (LSD) and N-demethyl-LSD from blood, serum, plasma, and urine samples using the Zymark RapidTrace with LC/MS/MS confirmation.

A forensic procedure for the quantitative confirmation of lysergic acid diethylamide (LSD) and the qualitative confirmation of its metabolite, N-demethyl-LSD, in blood, serum, plasma, and urine samples is presented. The Zymark RapidTrace was used to perform fully automated solid-phase extractions of all specimen types. After extract evaporation, confirmations were performed using liquid chromatography (LC) followed by positive electrospray ionization (ESI+) mass spectrometry/mass spectrometry (MS/MS) without derivatization. Quantitation of LSD was accomplished using LSD-d3 as an internal standard. The limit of quantitation (LOQ) for LSD was 0.05 ng/mL. The limit of detection (LOD) for both LSD and N-demethyl-LSD was 0.025 ng/mL. The recovery of LSD was greater than 95% at levels of 0.1 ng/mL and 2.0 ng/mL. For LSD at 1.0 ng/mL, the within-run and between-run (different day) relative standard deviation (RSD) was 2.2% and 4.4%, respectively.

Serum profiles of insulin-like growth factors and their binding proteins in adults with growth hormone receptor deficiency treated with insulin-like growth factor I.

Six adult patients with growth hormone receptor deficiency (GHRD) (2 men, 4 women) with an identical defect in the growth hormone receptor (GHR) gene, were treated with recombinant human insulin-like growth factor I (IGF-I), 40 micrograms/kg s.c. twice daily, for 7 days. Serum concentrations of IGF peptide and IGF binding protein-3 (IGFBP-3) were measured by specific radioimmunoassays; serum IGFBPs were also measured by Western ligand blotting. The size distribution of both IGF-I and IGF-II was measured in serum following size-exclusion fast-performance liquid chromatography. IGF-I treatment resulted in a normalization of serum IGF-I levels on days 1-7 of treatment and a decrease in serum IGF-II levels. The fall in IGF-II levels and the simultaneous rise in IGF-I levels, however, resulted in an unchanged total serum IGF level. The low IGFBP-3 values did not significantly change during treatment, whereas there was a slight increase in IGFBP-2 levels. Preliminary analysis of size-fractionated sera suggested an increase in IGF-I levels in the 40 and 150 kDa regions at the expense of IGF-II levels. The results suggest that despite the failure of IGF-I treatment to increase IGFBPs significantly, serum IGFBP concentrations were sufficient to maintain normal levels of IGF-I.