Biomedical subjects

D B Dunger

Publications and source records attributed to D B Dunger.

At least 163 records · Page 9Linked to original sources

PubMed1990

Insulin-like growth factor binding protein-1 levels in diabetic adolescents and their relationship to metabolic control.

Circulating levels of the low molecular weight insulin-like growth factor binding protein-1 (IGFBP-1) are insulin dependent and vary markedly throughout the day. IGFBP-1 levels are abnormally high in diabetes but the relationship between this and the metabolic status of the patient has not been defined. We have therefore measured fasting IGFBP-1 levels at 0800 h in 32 diabetic adolescents. IGFBP-1 was measured in 19 of these patients after a normal night and in 27 after a night of euglycaemia, maintained with a glucose clamp. In 13 patients both studies were performed and could be compared. Puberty-matched control data were obtained from 69 normal children. In normal prepubertal children IGFBP-1 levels were high; lower levels were found with advancing pubertal development. This fall in IGFBP-1 correlated with pubertal stage (r= 0.68, p less than 0.001) and with fasting insulin levels (r = 0.60, p less than 0.001) which rose with pubertal advancement. In the diabetic children IGFBP-1 levels also correlated inversely with the 0800 h free insulin level but there was no clear relationship with pubertal development. However, when measured after overnight euglycaemia IGFBP-1 levels correlated inversely with pubertal development (r = 0.67, p less than 0.001) as in the normal children. In the patients studied on two comparable occasions the IGFBP-1 level measured after a normal night relative to that measured under standardized euglycaemic conditions was found to correlate closely with the glycosylated haemoglobin level (r = 0.71, p less than 0.005).

Adolescent↗

PubMed1990

Growth hormone treatment in non-growth hormone-deficient children: effects of stopping treatment.

Overnight physiological growth hormone (GH) secretion was evaluated in 95 short, prepubertal children (73 boys, 22 girls). All the children were below the 3rd centile for height and achieved GH levels greater than 15 mU/l following pharmacological stimulation. The mean average GH level was 7.1 mU/l and the mean sum of pulse amplitudes 80.4 mU/l. No relationship was found between age, height or height velocity and any of the parameters of GH secretion. The group was randomized to receive placebo, GH or remain under observation for the first 6 months and then all patients received GH treatment for a further 6 months. Those treated with GH, 0.27 IU/kg (0.1 mg/kg) three times weekly, in the first phase, demonstrated a mean increase in height velocity SDS of 3.24. There was no difference in growth response between the placebo or observation groups. In the second 6-month period, all children received GH according to the same dose regimen; they were then observed for a further 6 months following its discontinuation. In the 6 months following withdrawal of GH, all groups showed a significant fall in height velocity SDS, which returned to pretreatment levels, without demonstrating 'catch-down' growth. Repeat sampling of overnight GH secretion within 3 days of discontinuing GH showed normal secretory patterns with a small reduction in mean peak amplitude. These results suggest that short children without classic GH insufficiency respond well to exogenous GH in the short term and return to pretreatment height velocities afterwards. Consequently, it may be possible to increase final adult height in such children by GH treatment.

Adolescent↗

PubMed1990

Human isophane or lente insulin? A double blind crossover trial in insulin dependent diabetes mellitus.

Fifty two children with insulin dependent diabetes mellitus were randomised to receive human isophane or lente insulin preparations in combination with soluble insulin in a double blind trial. Patients were seen every two months, and crossed over after four months of treatment. Control assessed by glycated haemoglobin was significantly lower in children on human isophane insulin, but fasting blood glucose and fructosamine concentrations and the number of episodes of hypoglycaemia were similar on both regimens. In five children on twice daily insulin regimens, insulin profiles throughout a 24 hour period demonstrated greater variability on lente compared with isophane insulin despite identically administered insulin doses. A questionnaire completed at the end of the study showed that two thirds of the children and/or their parents preferred the isophane insulin, and they gave perceived improvement of metabolic control as the major reason for their choice.

Adolescent↗

PubMed1990

Are measurements of height made by health visitors sufficiently accurate for routine screening of growth?

To find out whether measurements of height made by health visitors are sufficiently accurate for use in routine screening of children we carried out an interobserver and intraobserver reliability study. Height measurements were made on a group of 10 children aged 3 years old and 10 aged 4.5 years old by two sets of four health visitors. They used a Microtoise or wall chart and the measurements were compared with those made by a trained auxologist with a Harpenden stadiometer. For a single assessment of height both pieces of equipment gave reasonably accurate results. In a child aged 3 years, with height measured on the Microtoise as 100 cm, the true height could be expected--with 95% probability--to lie between 99.2 cm-101.8 cm. At the age of 4.5 years, if the measurement was 110 cm, the child's true height could be expected to lie between 108.9 cm and 111.9 cm. The narrowest confidence interval for the growth rate from 3 to 4.5 years was achieved with the Microtoise, taking the mean of three measurements. We conclude that measurements made by health visitors are sufficiently accurate for routine screening of height, and the use of such measurements for the calculation of height velocity could be improved by more structured training.

Anthropometry↗

PubMed1990

Increased overnight growth hormone concentrations in diabetic compared with normal adolescents.

To determine the extent to which spontaneous plasma GH concentrations are abnormal in adolescents with insulin-dependent diabetes mellitus we performed 12-h overnight plasma GH profiles in 21 diabetic adolescents (11 males and 10 females; aged 9.8-16.5 yr; median, 13.6 yr) and 34 healthy adolescent controls (17 males and 17 females; aged 9.1-20.9 yr; median, 13.1 yr). Data were analyzed using the pulse detection program Pulsar and time series analysis, and are presented with respect to age and puberty stage. Mean and maximum GH concentrations, sum of the peak amplitudes, and mean calculated baseline concentrations in the normal children were higher during puberty; highest levels were seen in girls at puberty stages 2-3, and in boys at stages 4-5. A similar pattern was observed in the diabetic adolescents, but all measures of pulse height and mean calculated baseline concentrations were significantly greater than those in the normal subjects (multivariate analysis, P less than 0.001). Pulse frequency did not change during puberty in the normal or diabetic subjects, and the dominant pulse periodicity in both groups was about 180 min. We conclude that the predominant change in GH release during puberty is in pulse amplitude, and that this is increased in diabetes, whereas pulse frequency remains constant in both normal and diabetic adolescents.

Adolescent↗

PubMed1990

A longitudinal study of total and free thyroid hormones and thyroxine binding globulin during normal puberty.

Thyroid hormones are essential for normal pubertal growth, yet the changes in total and, especially, free thyroid hormones and thyroxine-binding globulin during puberty have not been adequately defined. Serum from 39 normal children (20 girls, 19 boys) between the ages of 10 and 15 years were assayed for total T4, free T4, free T3 and thyroxine-binding globulin at 6-monthly intervals; the free hormone assays were valid, non-analogue methodologies. In the girls, free T4 levels fell from 15.7 +/- 0.6 pmol/l at 10 years to 13.0 +/- 0.6 (p less than 0.001) at 12.5 years before rising to 15.9 +/- 0.7 at 15 years; this nadir occurred at puberty stages 3-4. Changes in total T4 followed a similar pattern with a slight delay in the nadir (13 years, puberty stage 4). In the boys, free T4 fell from 16.3 +/- 0.6 pmol/l at 10 years to 14.3 +/- 0.3 at 13.5 years, then rising to 15.4 +/- 0.5 at 15 years; the nadir again occurred at puberty stages 3-4. The corresponding nadir in total T4 which occurred at puberty stages 4-5 was not apparent by age analysis. Thyroxine-binding globulin concentrations remained unchanged in the girls, but fell slightly in the boys during later puberty. Free T3 concentrations in the girls showed a progressive fall after 12.5 years which was significant by the age of 14 when most had been in puberty stage 5 for more than 1 year. The boys showed no change of free T3 concentration throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

Failure of current insulin regimes to meet the overnight requirements of adolescents with insulin-dependent diabetes.

The study was undertaken to determine whether overnight insulin requirements were being met during conventional insulin therapy in adolescents with IDDM. Overnight glucose and insulin profiles were compared when the subjects were on their usual insulin regime (baseline) and when the blood glucose was clamped using a variable rate insulin infusion (clamp). Thirteen adolescents (5 boys and 8 girls, median age 12.2 yr; range 10.5-15.4 yr; Median HBA1 11.4%; range 8.4-15.6) took part in the study. Three were on twice daily, two on multiple injection therapy and two on once daily insulin therapy. During the baseline studies, blood glucose concentrations fell to a nadir at 0200-0400 hr and then rose during the early hours of the morning. The clamp studies confirmed that the insulin requirement for euglycaemia was higher between 0500 and 0800 hr (15.4 +/- 0.9 mU/kg/hr) than between 0100 and 0400 (12.1 +/- 1.1 mU/kg/hr; p = 0.002). Comparison of the free insulin concentrations between the baseline and clamp nights, indicated that during the baseline study subjects were relatively over-insulinized during the early part of the night and under-insulinized during the latter part of the night irrespective of what insulin regime they were receiving. We conclude that current insulin regimes do not provide appropriate insulin delivery for the control of blood glucose during puberty.

Adolescent↗

PubMed1989

The frequency and natural history of diabetes insipidus in children with Langerhans-cell histiocytosis.

Diabetes insipidus is a well-recognized complication of Langerhans-cell histiocytosis (histiocytosis X), but its frequency and natural history are not well defined. Of 52 children with histiocytosis whom we studied, 12 (23 percent) had diabetes insipidus. Only two children had diabetes insipidus at presentation with histiocytosis, but the cumulative risk that it would develop during the first four years after the presentation and diagnosis of histiocytosis was found to be 42 percent. Diabetes insipidus occurred most often among children with multisystem disease and those with proptosis. To determine the natural history of diabetes insipidus in children with histiocytosis, we measured the response of urinary arginine vasopressin to water deprivation every six months in 21 children who did not have diabetes insipidus and who had had histiocytosis for less than four years. Five of the 21 children (24 percent) had subnormal responses during the initial test. One subsequently had spontaneous improvement in the functioning of the posterior pituitary, and diabetes insipidus subsequently developed in two, as it did in one of the children who initially had normal function of the posterior pituitary. Two of the children received irradiation to the pituitary within two to four weeks after diabetes insipidus developed, but they had no improvement in pituitary function. However, diabetes insipidus improved transiently during prednisolone therapy in one of these children and improved permanently after etoposide therapy in another child. We conclude that prospective study with the use of a simple water-deprivation test will allow partial defects of posterior-pituitary function to be detected in patients with histiocytosis and will permit a more appropriate evaluation of the effects of therapeutic intervention.

Adolescent↗

PubMed1989

Spontaneous growth hormone (GH) pulsatility is the major determinant of GH release after thyrotrophin-releasing hormone in adolescent diabetics.

GH release is abnormally regulated in insulin-dependent diabetes (IDDM), and paradoxical stimulation of GH release after TRH has been reported. However, overnight GH pulsatility is increased in IDDM, and it may be difficult to distinguish TRH-stimulated release from spontaneous secretory episodes. To resolve this question, we carried out two overnight GH profiles followed by either TRH or saline control tests in six adolescents with IDDM; ages 11.4-14.7 years, duration IDDM 2.4-6.7 years. A rise in GH was seen in four of six following TRH, but with no consistent pattern. A rise was also seen in four of six following saline. Peak GH levels were similar after TRH and saline (19.3 +/- 4.4 vs 25.8 +/- 5.5 mU/l; mean +/- SEM). Mean blood glucose was no different during TRH and saline tests (9.5 +/- 1.6 vs 7.5 +/- 0.6 mmol/l). The two subjects who had an early GH peak after TRH were those in whom GH levels had already begun to rise, suggesting the coincident occurrence of a spontaneous GH pulse. The timing of the next GH pulse could be predicted equally well after TRH and saline from the overnight secretory profile using autocorrelation. Paradoxical GH stimulation after TRH is not seen in adolescents with IDDM, but apparent responses may be due to timing coincident with the increased spontaneous pulsatility.

Adolescent↗

PubMed1989

Urinary growth hormone during puberty in normal and diabetic children.

The measurement of GH in urine may have many clinical applications, particularly in childhood. We have used a highly sensitive direct immunoradiometric assay to examine urinary GH excretion in children during puberty. Fifty-five healthy schoolchildren collected timed overnight urine samples. A further 36 children (15 normal, six of short stature and 15 diabetic) collected urine samples during a total of 50 overnight plasma GH secretory profiles (15-min sampling). Overnight urinary GH excretion increased during puberty, with a peak at breast stage 2 in girls, and genital stage 4 in boys, before declining at stage 5. There was a positive correlation (r = 0.57, p = 0.003) with height velocity in girls, but not in boys. At each puberty stage except 2, the diabetics excreted more urinary GH than the normal children. There was a highly significant correlation (r = 0.79, p less than 0.001) between mean overnight plasma GH concentrations and urinary GH excretion, suggesting that the latter accurately reflects physiological GH secretion.

Adolescent↗

PubMed1989

Relationship between the pubertal fall in sex hormone binding globulin and insulin-like growth factor binding protein-I. A synchronized approach to pubertal development?

In a cross-sectional study of 69 normal adolescents we have found sex hormone-binding globulin (SHBG) levels to fall in both males and females throughout the pubertal period. Multiple regression analysis revealed a close negative correlation with insulin in both sexes. Weaker correlations were also found between SHBG and circulating androgen concentrations, in both males and females. Similar results were also obtained for a second circulating binding protein of primarily hepatic origin. This low molecular weight insulin-like growth factor (IGF) binding protein I (IBP-I) is one of two distinct classes of IGF binding proteins which bind IGF-I and IGF-II. IGF-I in turn mediates, at least in part, the actions of growth hormone. IBP-I also fell throughout puberty, correlating with the increasing insulin levels. In addition IBP-I correlated with androgen levels in both sexes. These similarities between SHBG and IBP-I, together with a strong correlation across puberty between the levels of the two binding proteins themselves (r = 0.737, P less than 0.001), suggest common mechanisms of control over the circulating levels of these two binding proteins. The association with insulin raises the possibility of a synchronized modulation of the actions of sex steroids and IGFs by nutritional intake. Thus pubertal growth and sexual development may occur over the same time with both modulated according to nutritional intake, linked through pancreatic insulin release, to hepatic production of SHBG and IBP-I.

Adolescent↗

PubMed1989

Relationship between insulin, insulin-like growth factor I, and dehydroepiandrosterone sulfate concentrations during childhood, puberty, and adult life.

The relationships between plasma insulin, insulin-like growth factor I (IGF-I) and dehydroepiandrosterone sulfate (DHEAS) concentrations in normal subjects have not been defined. We performed iv glucose tolerance tests on 102 normal subjects, aged 5-20 yr. The subjects were divided into 4 groups according to pubertal stage (Tanner): A, stage 1 (n = 22); B, stages 2 and 3 (n = 17); C, stages 4 and 5 (n = 20); and D, adult, greater than 17 yr (n = 43). The basal plasma IGF-I and insulin concentrations and incremental 0-60 min insulin areas in response to glucose rose significantly throughout puberty (P less than 0.001 for all parameters) and declined to prepubertal levels by the third decade of life. There was a strong positive correlation between log fasting plasma insulin vs. log plasma IGF-I (r = 0.625; P less than 0.001) and log incremental 0-60 min insulin areas vs. log plasma IGF-I (r = 0.572; P less than 0.001). Plasma DHEAS concentrations were measured in groups A-C (n = 59); these also rose throughout puberty. There was strong correlations between log plasma DHEAS and log basal or stimulated (incremental 0-60 min areas) insulin responses (P less than 0.001). To assess the relationship between plasma DHEAS and insulin before puberty, we analyzed the data from group A separately. Plasma DHEAS concentrations tended to be higher in children 9 yr of age or older than in those less than 9 yr old, whereas basal and stimulated plasma insulin levels were similar. We found no correlation between log plasma insulin (fasting or stimulated responses) and log plasma DHEAS concentrations in group A (P greater than 0.05). In conclusion, we found a strong relationship between plasma insulin and IGF-I throughout childhood and puberty and during adult life. This finding suggests that insulin may be important for normal growth during childhood. There was no correlation between plasma insulin and DHEAS concentrations in prepubertal children, which suggests that adrenarche does not influence insulin levels.

Adolescent↗

PubMed1989

Levels of the small insulin-like growth factor-binding protein are strongly related to those of insulin in prepubertal and pubertal children but only weakly so after puberty.

We have looked at the relationship between fasting levels of insulin and a small insulin-like growth factor (IGF)-binding protein (IBP-1) in a cross-sectional study of 116 normal subjects aged 5-48 years. The relationship between IBP-1 and insulin was also examined within individual normal children in overnight profiles of IBP-1 and insulin obtained from two children at each stage of puberty (Tanner stages 1-5). In the cross-sectional study high levels of IBP-1 were found in early childhood and these fell throughout puberty as fasting levels of insulin rose. Multiple regression analysis revealed that both these changes were predominantly due to pubertal development rather than to age. After the age of 16 IBP-1 levels remained low despite fasting insulin levels returning to prepubertal levels. A strong negative correlation was obtained between IBP-1 and insulin in children of 5-16 years (r = -0.63; n = 60; P less than 0.001), no such relationship being found after the age of 16. In the second study, IBP-1 underwent a marked circadian variation in all cases and an inverse correlation with insulin, measured at the same time, was obtained at pubertal stages 1 to 4, but not at stage 5 (pooled data stages 1-4, r = -0.69; n = 53; P less than 0.001). We have demonstrated that a potential inhibitor of IGF-activity is inversely related to insulin throughout the period of active GH-related growth and that this relationship weakens after puberty.

Adolescent↗

PubMed1989

Comparison of insulin autoantibodies in diabetes-related and healthy populations by precise displacement ELISA.

The second international workshop on insulin autoantibodies (IAAs) demonstrated improved concordance among laboratories with both radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) when measurements were based on signals displaceable by preincubation with excess insulin. This feature has been incorporated into our original ELISA for IAAs, and the assay was used to compare IAAs in diabetes-related and healthy populations. The serum from a healthy islet cell antibody (ICA)+ and IAA+ subject was used to construct standard curves with and without preincubation with 1 U/ml human insulin. Reporting results in arbitrary displacement (delta +/- IAA) units derived from the standard curve improved precision and increased the specificity of the assay. Frequency analysis of the results from 200 control adults did not show a normal distribution, and cumulative frequency analysis demonstrated two populations: 10 of 200 (5%) control adults, 8 of 241 (3.3%) healthy schoolchildren, and 18 of 229 (7.9%) non-insulin-dependent diabetes mellitus (NIDDM) patients had IAAs greater than 12 delta +/- IAA units. On the same basis, we tested samples from 89 individuals in the prospective Bart's Windsor Family Study for insulin-dependent diabetes mellitus (IDDM), 31 of whom had ICAs greater than 5 Juvenile Diabetes Foundation (JDF) units. Of those with ICAs greater than 5 JDF units, 12 developed IDDM and 1 developed NIDDM in 10 yr of study. IAAs greater than 12 delta +/- IAA units were found in 6 of 12 (50%) who became diabetic and in 4 of 18 (22%) who remain healthy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Pancreatic exocrine and endocrine function after subtotal pancreatectomy for nesidioblastosis.

Pancreatic exocrine and endocrine function was assessed in seven patients 1 to 2 years after 95% pancreatectomy (group A) and three patients 9 to 11 years after 75% pancreatectomy (group B). In all cases surgery was undertaken for the treatment of hyperinsulinism and the histologic diagnosis was nesidioblastosis. The activities of pancreatic enzymes and bicarbonate concentrations were generally normal in group B, but were reduced in approximately half the children in group A. One child in group A had significant exocrine failure and poor weight gain. Blood glucose levels and fasting insulin levels were normal during a standard glucose tolerance test in all of the group B patients. One had a low fasting blood glucose level. In the group A patients three had low fasting glucose levels and one a frankly diabetic glucose tolerance test. C peptide and insulin levels were comparable but inappropriate insulin levels were noted in one patient, suggesting that the control of glucose-stimulated insulin release may remain abnormal. The results suggest that pancreatic function is not seriously impaired in the majority of patients 1 to 2 years after 95% pancreatectomy and that it is comparable to that noted in 75% pancreatectomy patients followed over a longer period of time.

Amylases↗

PubMed1988

Circadian variation of GH-independent IGF-binding protein in diabetes mellitus and its relationship to insulin. A new role for insulin?

Evidence is accumulating that a non-GH dependent insulin-like growth factor-binding protein (IGF-BP) is not only a carrier protein but also has an active role in the growth process. We have measured levels of this IGF-BP, using a specific RIA, over 12 or 24-h periods in 11 adolescents with diabetes mellitus and five normal adults. In each of the normal the IGF-BP was undetectable for most of the day but with a broad nocturnal peak observed, with levels up to 50 micrograms/l. The levels of IGF-BP were unrelated to the secretory pattern for GH but correlated inversely with the concentration of circulating insulin. In the diabetics a very similar pattern was observed, but with detectable levels throughout the day and much higher peak levels seen at night. Peak levels were up to 120 micrograms/l if a long-acting insulin preparation was administered in the evening but were 400-500 micrograms/l if the long-acting preparation was administered in the morning. The IGF-BP was strongly correlated with plasma glucose in this latter group. In a further group of diabetics overnight profiles were obtained on two separate nights, a normal night and a night with euglycaemia maintained with a glucose clamp technique. Euglycaemia failed to affect peak levels of the binding protein, although the shape of the nocturnal peak was altered consistent with the altered pattern of circulating free insulin. In this group a strong inverse correlation was obtained between the IGF-BP and free insulin levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1988

Familial olivopontocerebellar atrophy with neonatal onset: a recessively inherited syndrome with systemic and biochemical abnormalities.

Clinical and pathological findings are reported in two siblings who presented in the neonatal period with failure to thrive, hypotonia, pericardial effusions, limitation of joint movement, retinal dystrophy and loss of visual function. Additional features were biochemical evidence of purine overproduction and liver dysfunction. Post mortem, the neuropathological findings in both children were typical of olivopontocerebellar atrophy. It is suggested that the cases represent a recessively inherited inborn error of metabolism.

Brain↗

PubMed1988

A short water deprivation test incorporating urinary arginine vasopressin estimations for the investigation of posterior pituitary function in children.

The value of a 7-h water deprivation test incorporating urinary osmolality and urinary arginine vasopressin (AVP) measurements was investigated in 20 children with suspected anterior or posterior pituitary dysfunction (group A) and 11 presenting with polyuria and polydipsia (group B). A control group of 16 healthy children was also studied. Urinary osmolalities in the control subjects after 7 h of water deprivation were 827-1136 mosmol/kg and urinary AVP 114-320 pmol/l. Of the group A patients, 5 had symptomatic diabetes insipidus with urinary osmolalities less than 300 mosmol/kg, and urinary AVP concentrations of less than 10 pmol/l, and 5 had normal urinary concentrating ability. The other 10 patients had varying degrees of partial diabetes insipidus (urinary AVP 6-53 pmol/l) although in 3 urinary concentrating ability was well maintained (osmolality 650-747 mosmol/kg). In group B, a diagnosis of compulsive water drinking was made in 9 patients, 1 had nephrogenic diabetes insipidus (urinary osmolality 68 mosmol/kg, AVP 782 pmol/l), and the final patient had transient diabetes insipidus. The test described was easy to perform and well tolerated even in young children. Using this test alone, it was possible to identify patients with partial defects of posterior pituitary function even when urinary concentrating ability was maintained, as well as those with complete cranial diabetes insipidus, nephrogenic diabetes insipidus, and compulsive water drinking.

Adolescent↗