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R Lanes

Publications and source records attributed to R Lanes.

At least 37 records · Page 2Linked to original sources
PubMed1996

Once daily subcutaneous growth hormone-releasing hormone therapy accelerates growth in growth hormone-deficient children during the first year of therapy. Geref International Study Group.

The efficacy and safety of 1 yr of GH-releasing hormone [GHRH-(1-29)] therapy in GH-deficient children were determined. One hundred and ten previously untreated prepubertal GH-deficient children were treated for up to 1 yr in a multicenter, open label study with 30 micrograms/kg GHRH-(1-29)/day, sc, given at bedtime. Eighty-six of the 110 patients were eligible for efficacy analysis. The main outcome measures, monitored every 3-6 months, were linear growth enhancement (height velocity), bone age progression, and safety measures including clinical chemistry. The mean height velocity for the group increased from 4.1 +/- 0.9 cm/yr at baseline to 8.0 +/- 1.5 and 7.2 +/- 1.3 cm/yr after 6 and 12 months of therapy, respectively. At 6 months, 74% of the children were considered to have a good response to GHRH. The ratio of the change in bone age to height age was not significantly different from unity at 12 months (1.04 +/- 0.58; P = 0.63). No adverse changes in general biochemical or hormonal analyses were noted. No change in fasting glucose concentration or excessive generation of insulin-like growth factor I occurred, and overall GHRH was well tolerated. We conclude that GHRH administered as a once daily dose of 30 micrograms/kg GHRH.(1-29), s.c., was effective in increasing height velocity in GH-deficient children.

Adolescent↗
PubMed1995

Short- and long-term effect of oral salbutamol on growth hormone secretion in prepubertal asthmatic children.

Salbutamol, a beta 2-adrenergic agonist, is being extensively used in Venezuela as a brochodilator in the treatment of asthma in children. Previous reports have shown oral salbutamol either to inhibit or not to affect growth hormone (GH) secretion. We evaluated the effect of oral salbutamol (0.1 mg/kg every 6 hours for 3 months) on GH secretion in eight prepubertal short children with mild asthma. Levels of GH during sleep (samples taken every 30 minutes from 9 PM to 6 AM) and after GH-releasing hormone ([GHRH] 1 microgram/kg intravenously [IV]) were measured before, at 24 hours, and at 3 months of salbutamol treatment. Overnight integrated concentrations of GH and peak GH levels following GHRH diminished significantly after 24 hours of salbutamol therapy (from 4.5 +/- 1.3 to 3.4 +/- 0.8 micrograms/L and from 46.6 +/- 47.3 to 16.2 +/- 7.9 micrograms/L, respectively, P < .05). However, GH levels after 3 months of salbutamol were not different from basal levels (4.5 +/- 1.3 v 5.1 +/- 5.1 +/- 2.9 micrograms/L during the overnight studies and 46.6 +/- 47.3 v 37.8 +/- 30.4 micrograms/L after GHRH). Our data suggest an inhibition of both spontaneous and stimulated GH secretion following short-term oral salbutamol ingestion, but this suppressive effect is not maintained with its long-term use.

Administration, Oral↗
PubMed1995

Bone mineral density of prepubertal age girls with Turner's syndrome while on growth hormone therapy.

Bone mineral densities and growth velocities of young girls with Turner's syndrome treated with recombinant human growth hormone at an age before the decreased levels of estrogens secondary to their ovarian failure could contribute to osteopenia were studied. Twelve patients with a mean chronological age of 8.9 +/- 0.9 years and a mean bone age of 6.9 +/- 0.8 years received growth hormone therapy for over 2 years (0.5 IU/kg/week s.c.) Mean growth velocities increased significantly from a baseline level of 3.5 +/- 0.4 cm/year to 6.4 +/- 0.3 and 5.7 +/- 0.4 cm/year at 12 and 24 months of therapy, while height SDS improved from -3.1 +/- 0.4 at baseline to -2.7 +/- 0.3 and -2.4 +/- 0.3 at 12 and 24 months, respectively. Total bone calcium as well as cortical bone mineral density of our density of our patients while on recombinant human growth hormone were similar to that of a control group of prepubertal healthy growth children paired for bone age and height; bone density of trabecular bone was however increased in our patients when compared to healthy controls (0.791 +/- 0.04 vs. 0.669 +/- 0.02 g/cm2; p < 0.025). We conclude from our study that the bone mineral status of young girls with Turner's syndrome on growth hormone therapy seems to be normal.

Age Determination by Skeleton↗
PubMed1994

HLA-DQA1 and DQB1 allele and genotype contribution to IDDM susceptibility in an ethnically mixed population.

HLA-DRB1, DQA1 and DQB1 alleles have been determined in 42 families with one IDDM proband and 64 healthy controls, by oligotyping (PCR-SSO) using primers and probes from the XI International Histocompatibility Workshop. A positive DRB1*03 and DRB1*04 association with the disease was observed, whereas DRB1*11 and DRB1*07 showed negative association but 19% of patients carried DRB1 alleles different to DRB1*03 or *04. When single alleles were considered, DQA1*03 showed the strongest association with susceptibility to the disease (RR = 8.2, Pc = 0.00001) but this association was outgrown by 2 and 3 allele combinations, with genotype DRB1*04-DQA1*03-DQB1*0302/DRB1*03- DQA1*0501- DQB1*0201 showing the strongest association (RR = 28, Pc = 0.002). Application of the relative predispositional effect (RPE) method to our data, revealed a further susceptibility risk provided by the DRB1*13-DQA1*0102-DQB1*0604 haplotype once DR3 and DR4 haplotypes were removed. When DQA1-DQB1 genotypes were analysed for presence of Arg 52 (DQ alpha) and absence of Asp 57 (DQ beta), genotypes SS/SS were found significantly increased in diabetics. Interestingly, one of the strongest associations with the disease was observed with the DQA1*03-DQB1*0201 combination encoded mainly by genes in trans (RR = 11.7 Pc = 0.00004). These observations and their comparison with DR-DQ haplotypes in more homogeneous ethnic groups support the stronger influence of the DQ molecule rather than the individual DR or DQ alleles in the susceptibility to IDDM. They also emphasize the need for detailed HLA haplotype studies in non-Caucasian and ethnically mixed populations to gain further insight into the nature of genetic and environmental factors contribution to autoimmunity.

Alleles↗
PubMed1992

Sustained improvement in growth velocity and recovery from suboptimal growth hormone (GH) secretion after treatment with human pituitary GH-releasing hormone-(1-44)-NH2.

The sustained effect of human pancreatic GH-releasing hormone [hpGHRH-(1-44)-NH2] on growth rate and GH secretory patterns was studied in 14 patients (10 males and 4 females; aged 10-16 yr; all Tanner stage I or II). Nine children had inadequate spontaneous GH secretion (ISGHS), while 5 had classic GH deficiency. Seven of 9 patients with ISGHS and 1 of 5 patients with GH deficiency were given 2 sc injections/day of 5 micrograms/kg GHRH for 2-3 months; the others received 5 pulses of GHRH (5 micrograms/kg BW.pulse) for 6 nights a week for 2-13 months, given every 3 h. Six of the nine ISGHS patients increased their growth velocity in response to GHRH therapy. These same six patients maintained an increased growth velocity for up to 24 months after GHRH was discontinued. The remaining three ISGHS patients did not show a significant growth response to GHRH administration. Neither a temporary nor a sustained growth response was correlated with spontaneous overnight GH secretion in these patients. In contrast, three of five classical GH deficiency patients exhibited increased growth velocity while undergoing GHRH therapy, but growth returned to preintervention rates upon discontinuation of treatment. The other two of the five classic GH deficiency patients failed to demonstrate any growth response to GHRH treatment. The increased growth velocity that was sustained for long intervals even after discontinuation of GHRH in ISGHS patients may indicate restoration of normal regulation of the hypothalamic-pituitary GH secretion axis.

Child↗
PubMed1990

ACTH stimulation tests and plasma dehydroepiandrosterone sulfate levels in women with hirsutism.

BACKGROUND: Hirsutism in women is a clinical manifestation of excessive production of androgens. The source of the excess androgen may be either the ovaries or the adrenal glands, and distinguishing between these sources may be difficult. METHODS: To determine whether measurements of plasma dehydroepiandrosterone (DHEA) sulfate and ACTH stimulation tests, both widely used in the evaluation of hirsutism in women, provide useful information, we performed both tests in 22 normal women and 31 female patients with hirsutism. The hormones measured in plasma during the ACTH stimulation tests were progesterone, 17-hydroxypregnenolone, 17-hydroxyprogesterone, DHEA, androstenedione, 11-deoxycortisol, and cortisol. RESULTS: The women with hirsutism were divided into four groups based on their individual responses to ACTH stimulation: patients with a possible 3 beta-hydroxy-delta 5-steroid dehydrogenase deficiency, those with a possible 21-hydroxylase deficiency, those with a possible 11 beta-hydroxylase deficiency, and those with no apparent defect in steroidogenesis. The results in 19 patients (61 percent) suggested subtle defects in adrenal steroidogenesis. There was no significant correlation between the basal plasma DHEA sulfate levels and the hormonal response to ACTH, nor were the basal levels of hormones predictive of the levels after ACTH stimulation. Eleven patients had significantly elevated basal levels of plasma DHEA sulfate; only 5 of these 11 had responses to ACTH suggestive of compromised steroidogenesis. Thirteen patients who had responses suggestive of defective steroidogenesis had DHEA sulfate levels within the normal range. CONCLUSIONS: A substantial proportion of women with hirsutism have mild defects in adrenal steroidogenesis, revealed by an ACTH stimulation test, that are indicative of late-onset (nonclassic) congenital adrenal hyperplasia. Measurements of basal steroid levels are not helpful in differentiating among the causes of increased androgen production in such patients and may be misleading.

17-alpha-Hydroxypregnenolone↗
PubMed1990

Growth hormone therapy in a poorly growing child with hypophosphatemic rickets.

We treated a 10 6/12 year old prepubertal male with hypophosphatemic rickets, who was growing poorly despite appropriate treatment with calcitriol and phosphate, with exogenous growth hormone (for an initial trial period of 4 months, followed by 14 months of continuous treatment at a dose of 4 IU three times weekly) even though his growth hormone testing proved to be normal. His growth rate increased significantly during treatment with synthetic growth hormone (from a basal rate of 3.9 cm/yr to 9 cm/yr during the first 4 months of therapy and from 2.7 cm/yr to 6.0 cm/yr during next 14 months of treatment) and his predicted adult height increased as well. Slight metabolic changes were detected in this patient during treatment, with an increase in serum phosphorus and a decrease in twenty-four hour urine calcium concentrations. It would seem reasonable to evaluate the growth hormone status of children with hypophosphatemic rickets who are growing poorly despite appropriate therapy with calcitriol and phosphate and to consider a trial period of therapy with growth hormone in some of them.

Body Height↗
PubMed1990

Growth hormone secretion in pubertal age patients with Turner's syndrome.

GH levels were measured every 30 min during sleep over 9 h in 10 patients with Turner's syndrome ranging in age from 10.6-18.9 yr (mean, 15.0 +/- 2.7 yr) and in 12 controls matched for bone age, all of whom had normal GH responses to an orally administered dose of clonidine. We found no significant difference in the mean 9-h overnight GH concentration between groups. The overnight GH concentration was 3.8 +/- 2.2 micrograms/L (mean +/- SD) in Turner's syndrome patients and 4.5 +/- 2.4 micrograms/L in the control group. Total GH output (205.4 +/- 118.7 vs. 251.4 +/- 122.0 U), total number of nocturnal GH pulses (2.4 +/- 0.8 vs. 2.9 +/- 0.7), and mean peak GH response during nocturnal sampling (13.0 +/- 7.4 vs. 13.2 +/- 3.3 micrograms/L) were not different in the children with Turner's syndrome and the controls. We conclude that pubertal age patients with Turner's syndrome secrete GH normally and do not have any abnormality in GH regulation.

Adolescent↗
PubMed1989

Diagnostic limitations of spontaneous growth hormone measurements in normally growing prepubertal children.

To evaluate whether the measurement of the spontaneous overnight growth hormone secretion in prepubertal children clearly separated normal children from subjects with growth hormone deficiency, we studied 45 prepubertal normally growing children (10 with normal height and 35 with constitutional growth delay) and compared their overnight growth hormone secretion with that of a group of subjects with either isolated growth hormone deficiency or neurosecretory dysfunction. Peak growth hormone levels (greater than or equal to 10 ng/mL) following oral clonidine administration were normal in individuals with normal height, constitutional growth delay, and neurosecretory dysfunction, as was the basal somatomedin C concentration; subjects with growth hormone deficiency had low peak growth hormone levels (less than 10 ng/mL) following oral clonidine administration as well as low basal somatomedin C values. The mean 9-hour overnight growth hormone concentration, total growth hormone output, total number of nocturnal pulses, and the mean peak growth hormone response during nocturnal sampling were similar in the normal height and constitutional growth delay groups and significantly greater than those seen in subjects with either growth hormone deficiency or neurosecretory dysfunction. Twelve (26.6%) of 45 normally growing children (4 to 10 normal height and 8 of 35 constitutional growth delay), however, had low overnight growth hormone levels (less than 3 ng/mL), which overlapped results obtained in the growth hormone-deficient or neurosecretory dysfunction groups. Frequent overnight growth hormone (GH) sampling does not always separate normal-growing children from those with partial or complete GH deficiency. In our this study over one quarter of the normally growing children had overnight GH levels in the range of children with either GH deficiency or neurosecretory dysfunction. These findings, in addition to the cost and difficulty in performing this test, do not support the measurement of spontaneous GH as a routine test in short but normally growing prepubertal children.

Adolescent↗
PubMed1989

The metoclopramide test: a useful tool with the luteinizing hormone-releasing hormone test in distinguishing between constitutional delay of puberty and hypogonadotropic hypogonadism.

To evaluate the effectiveness of intravenous metoclopramide, alone or in combination with luteinizing hormone-releasing hormone (LH-RH), in distinguishing between constitutional delay of puberty and hypogonadotropic hypogonadism, 12 patients with constitutional delay of puberty and 10 patients with hypogonadotropic hypogonadism were studied. All patients received 10 mg/m2 of intravenous metoclopramide and 100 micrograms of intravenous LH-RH on separate days. The mean prolactin (PRL) response following metoclopramide was significantly higher in the constitutional delay of puberty group when compared with the hypogonadotropic hypogonadism patients (P less than 0.01 at 15, 30, 45, and 60 minutes); all patients with constitutional delay of puberty increased their PRL level to greater than or equal to 60 ng/ml, except one who had a peak PRL level of 38 ng/ml. While only 2 of the hypogonadotropic hypogonadism subjects reached a peak PRL concentration of greater than or equal to 60 ng/ml, 4 had peak PRL levels greater than 38 ng/ml. The mean LH and follicle-stimulating hormone (FSH) responses after LH-RH were significantly higher in the constitutional delay of puberty group (P less than 0.01 at 30, 45, and 60 minutes for LH and P less than 0.01 at 45 and 60 minutes for FSH). All constitutional delay of puberty subjects responded to both the metoclopramide and LH-RH tests, while patients with hypogonadotropic hypogonadism responded only to one or to neither of these tests. Therefore, while metoclopramide alone did not allow us to clearly distinguish constitutional delay of puberty from hypogonadotropic hypogonadism, the combined use of both of these stimuli permitted us to detect all subjects with constitutional delay of puberty.

Adolescent↗
PubMed1989

Growth hormone release in response to growth hormone-releasing hormone in term and preterm neonates.

The growth hormone response to a single intravenous dose of human growth hormone-releasing hormone (GHRH) was examined in 23 healthy neonates (12 term and 11 preterm) aged 2-4 days. There were no significant increases in growth hormone concentrations at any point in time studied following GHRH administration in either group of newborns. The mean basal growth hormone levels of term neonates were significantly higher than those of the premature newborns (39.6 +/- 5.3 vs. 23.2 +/- 3.3 ng/ml; p less than 0.01) and this difference in growth hormone remained significant 15 and 30 min after GHRH injection. Gestational age correlated positively with both basal and peak growth hormone concentrations in our patients. In conclusion, first, neonates studied in their first days of life have high basal levels of growth hormone and fail to further secrete any significant amount of growth hormone following a single dose of GHRH, and, second, premature newborns secrete significantly less growth hormone than do term neonates.

Dose-Response Relationship, Drug↗
PubMed1987

Glycemic response in children with insulin-dependent diabetes mellitus after high- or low-glycemic-index breakfast.

To examine the effects of various carbohydrate foods on postprandial glycemia in diabetic children, we fed a mixed, isocaloric diet containing either high- or low-glycemic-index (GI) breakfast foods to 22 children with poorly controlled insulin-dependent diabetes mellitus (IDDM) and measured blood sugar response with and without adjustment of insulin doses. We found that IDDM children fed a high-GI meal showed a significantly higher serum glucose level than those fed a low-GI meal. However, such differences were not seen when the preprandial dose of regular insulin was adjusted to the amount of carbohydrate in feedings. Thus, as long as proper adjustment of insulin is made, the type of carbohydrate in a single mixed meal does not appear to have a significant effect on the postprandial glycemic response in children with long-standing poorly controlled IDDM.

Adolescent↗
PubMed1987

HCG stimulation in children with cryptorchidism.

Fifty-eight children with cryptorchidism have been given hCG stimulation testing, 31 with bilateral cryptorchidism, 22 with unilateral, and 5 with prior unsuccessful orchiopexy. Hormonal studies were carried out prior to and following stimulation. In bilateral cryptorchidism, bilateral descent was observed in 32 percent of cases and in unilateral, the success rate was 55 percent. From their data, the authors concluded that hCG is not indicated if patients present elevated LH and FSH levels or if the basal T levels are in the pubertal range. In the other subjects, the hCG test will permit the determination of the presence or absence of testosterone production and in some cases it results in testicular descent. Finally, in cases of failure that require surgery, the hCG will stimulate tissue growth enhancing the success of orchiopexy.

Adolescent↗
PubMed1987

Constitutional delay of growth and pubertal development: growth hormone secretory pattern and possible therapy.

Constitutional delay of growth and pubertal development is a frequent cause of short stature. These children have a significant retardation of skeletal age and delayed sexual development. They generally maintain a normal growth curve and tend to attain normal adult height. Although children with constitutional delay of growth are believed to have no medical or endocrine abnormality to explain their short stature, some controversy regarding their growth hormone secretory status has recently surfaced; some authors have reported low growth hormone levels to provocative stimuli and decreased growth hormone secretion during sleep, as well as low somatomedin C values in some children with constitutional delay of growth. Others, however, have found the growth hormone secretory status to be normal and similar to that of a control population. The implications of these findings, particularly in regard to possible forms of therapy, are discussed in some detail.

Adolescent↗
PubMed1986

Evaluation of the pituitary-thyroidal axis in newborns undergoing exchange transfusion.

To evaluate whether the hypothyroxinaemia, previously noted in hyperbilirubinaemic newborns immediately after exchange transfusion for Rh or AB0 incompatibility, was due to impairment in the secretion of thyroid stimulating hormone (TSH) by the pituitary, we studied the thyroid hormone response to thyrotropin releasing hormone (TRH) and compared this response to that seen in a control population of healthy neonates. All infants studied responded with a brisk TSH increase; 30 min after TRH injection the mean TSH concentration of the hyperbilirubinaemic patients was 37 microU/ml, ten times their basal level, which was not different from the value noted in the control population. No significant change in total thyroxine (T4), 3,5,3' triiodothyronine (T3), free thyroxine (FT4) or 3,3',5' triiodothyronine (rT3), (FT4) or (rT3) was noted after TRH administration in either group of neonates. In addition the effect of exchange transfusion on the thyroid axis of hyperbilirubinaemic newborns was evaluated. Before the exchange transfusion TSH, T4, rT3, T3 and FT4 levels were higher in the hyperbilirubinaemic newborns than in donor blood; immediately post-exchange transfusion TSH and T4 concentrations of the hyperbilirubinaemic neonates decreased significantly and remained significantly below pre-exchange values 30 h later. Newborns undergoing an exchange transfusion respond appropriately to TRH stimulation and seem to have an intact pituitary-thyroidal axis.

Exchange Transfusion, Whole Blood↗
PubMed1986

Premarin priming does not alter growth hormone release following exercise.

We evaluated the usefulness of premarin priming on exercise induced growth hormone release and the value of combining several growth hormone screening agents in a large population of prepubertal children. Two hundred five short healthy prepubertal children growing below the 5th percentile in height were studied. One hundred forty-four were screened with exercise following glucose ingestion, while 61 were primed with estrogen prior to glucose and exercise testing. Premarin priming did not significantly increase the number of our patients who responded to exercise nor to glucose; 86% and 88.5% of non-primed and primed patients, respectively, responded with a growth hormone increase greater than or equal to 8 ng/ml following exercise and glucose. Glucose loading alone was not associated with a high enough growth hormone rise to rule out growth hormone deficiency in most of our children. Age (less than or equal to 5 yr) was associated with lower post-exercise growth hormone levels and a higher failure rate to testing in both primed and non primed children. Premarin priming does not seem to alter the growth hormone releasing capacity to exercise of prepubertal children. The combined use of exercise, glucose loading and premarin priming in a single screening test does not improve on the results obtained by growth hormone exercise screening alone.

Adolescent↗