Home Use of an Artificial Beta Cell in Type 1 Diabetes

BACKGROUND

The feasibility, safety, and efficacy of prolonged use of an artificial beta cell (closed-loop insulin-delivery system) in the home setting have not been established.

METHODS

In two multicenter, crossover, randomized, controlled studies conducted under free-living home conditions, we compared closed-loop insulin delivery with sensor-augmented pump therapy in 58 patients with type 1 diabetes. The closed-loop system was used day and night by 33 adults and overnight by 25 children and adolescents. Participants used the closed-loop system for a 12-week period and sensor-augmented pump therapy (control) for a similar period. The primary end point was the proportion of time that the glucose level was between 70 mg and 180 mg per deciliter for adults and between 70 mg and 145 mg per deciliter for children and adolescents.

RESULTS

Among adults, the proportion of time that the glucose level was in the target range was 11.0 percentage points (95% confidence interval [CI], 8.1 to 13.8) greater with the use of the closed-loop system day and night than with control therapy (P<0.001). The mean glucose level was lower during the closed-loop phase than during the control phase (difference, -11 mg per deciliter; 95% CI, -17 to -6; P<0.001), as were the area under the curve for the period when the glucose level was less than 63 mg per deciliter (39% lower; 95% CI, 24 to 51; P<0.001) and the mean glycated hemoglobin level (difference, -0.3%; 95% CI, -0.5 to -0.1; P=0.002). Among children and adolescents, the proportion of time with the nighttime glucose level in the target range was higher during the closed-loop phase than during the control phase (by 24.7 percentage points; 95% CI, 20.6 to 28.7; P<0.001), and the mean nighttime glucose level was lower (difference, -29 mg per deciliter; 95% CI, -39 to -20; P<0.001). The area under the curve for the period in which the day-and-night glucose levels were less than 63 mg per deciliter was lower by 42% (95% CI, 4 to 65; P=0.03). Three severe hypoglycemic episodes occurred during the closed-loop phase when the closed-loop system was not in use.

CONCLUSIONS

Among patients with type 1 diabetes, 12-week use of a closed-loop system, as compared with sensor-augmented pump therapy, improved glucose control, reduced hypoglycemia, and, in adults, resulted in a lower glycated hemoglobin level. (Funded by the JDRF and others; AP@home04 and APCam08 ClinicalTrials.gov numbers, NCT01961622 and NCT01778348.).

Deprivation and ethnicity impact on diabetes control and use of treatment regimen

AIMS

Deprivation and/or ethnicity impact on care delivery. We have assessed how these factors influence diabetes care in a paediatric clinic.

METHODS

We related access to care [type of insulin treatment regimen-twice daily, multiple daily injections and insulin pump therapy (continuous subcutaneous insulin infusion)], measures of care process (HbA(1c)) and an approximate measure of satisfaction with the service (clinic attendance rate) in 325 (170 male) children and young people with Type 1 diabetes (mean age 10.6 years, mean duration of diabetes of 4.5 years), with indices of deprivation and ethnicity.

RESULTS

Of the 325 children and young people, 2.7% received twice-daily insulin, 48.4% multiple daily injections and 48.9% continuous subcutaneous insulin infusion. Median clinic HbA(1c) was 62 mmol/mol (7.8%) and those receiving the insulin pump therapy had the lowest HbA(1c). Four ethnic groups were represented; White British 81.6%, Asian non-Indian 6.5%, African 8.1% and Asian Indian 3.8%. Mean deprivation score was 21.06. White British and Asian Indian groups were more likely to receive insulin pump therapy (χ(2) = 50.3; P < 0.001). Attendance rates were 94.1% and did not differ across ethnic groups. Deprivation was related to ethnicity and HbA(1c) (R(2) = 0.02; P = 0.02). There was no relationship between clinic attendance and deprivation. Insulin regimen and ethnicity were associated with HbA(1c) (R(2) = 0.096; P < 0.001). Similar findings were obtained when analysis was confined to the White British population.

CONCLUSIONS

These data suggest that deprivation and ethnicity influence diabetes control and how intensive insulin therapy is utilized. A better consideration of the needs of different ethnic groups is required to ensure equitable care delivery in paediatric diabetes.

Use of intravenous etomidate to control acute psychosis induced by the hypercortisolaemia in severe paediatric Cushing's disease

BACKGROUND

Psychosis secondary to paediatric Cushing's disease (CD) is extremely rare and presents a significant management challenge.

METHOD

We report a 14.7-year-old CD patient with acute psychosis and self-inflicted injuries following failed transsphenoidal pituitary surgery. Her mental state rapidly deteriorated precluding medical therapy.

RESULTS

Emergency intravenous low-dose etomidate infusion (3-3.5 mg/h) with dose titration according to the serum cortisol combined with a hydrocortisone infusion, in an intensive care setting, was effective in controlling the hypercortisolaemia. Her mental state improved with normalisation of her cortisol levels enabling oral administration of ketoconazole and bilateral adrenalectomy to be performed.

CONCLUSION

This case illustrates the safe and effective use of a low-dose etomidate infusion in an unusual case of paediatric CD.

Do centimetres matter? Self-reported versus estimated height measurements in parents

AIM

An impressive discrepancy between reported and measured parental height is often observed. The aims of this study were: (a) to assess whether there is a significant difference between the reported and measured parental height; (b) to focus on the reported and, thereafter, measured height of the partner; (c) to analyse its impact on the calculated target height range.

METHODS/RESULTS

A total of 1542 individual parents were enrolled. The parents were subdivided into three groups: normal height (3-97th Centile), short (<3%) and tall (>97%) stature. Overall, compared with men, women were far better in estimating their own height (p < 0.001). Where both partners were of normal, short or tall stature, the estimated heights of their partner were quite accurate. Women of normal stature underestimated the short partner and overestimated the tall partner, whereas male partners of normal stature overestimated both their short as well as tall partners. Women of tall stature estimated the heights of their short partners correctly, whereas heights of normal statured men were underestimated. On the other hand, tall men overestimated the heights of their female partners who are of normal and short stature. Furthermore, women of short stature estimated the partners of normal stature adequately, and the heights of their tall partners were overestimated. Interestingly, the short men significantly underestimated the normal, but overestimated tall female partners.

CONCLUSION

Only measured heights should be used to perform accurate evaluations of height, particularly when diagnostic tests or treatment interventions are contemplated. For clinical trails, we suggest that only quality measured parental heights are acceptable, as the errors incurred in estimates may enhance/conceal true treatment effects.

Murphy's Law and the pregnant medical doctor: is pregnancy outcome worse?

The 'Murphy's Law' concept that doctors have a higher incidence of adverse pregnancy outcome is often quoted anecdotally but has never been scientifically tested. A group of medical doctors (n =52) were prospectively matched closely with a group of non-doctors (n =52) and pregnancy outcome was recorded. There were no differences noted in pregnancy outcome between the two groups. Whilst a much larger number of doctors is probably required to show a statistically significant difference, this first small study shows no clinically relevant difference between the two groups. The perception of Murphy's Law and the pregnant medical doctor would appear to be a myth.

Childhood body mass index (BMI), breastfeeding and risk of Type 1 diabetes: findings from a longitudinal national birth cohort

AIMS

To perform a longitudinal analysis of the association between childhood body mass index (BMI) and later risk of Type 1 diabetes, controlling for socio-economic status, birthweight, height in early and late childhood, breastfeeding history and pubertal status.

METHODS

Analysis of the 1970 British Birth Cohort, followed up at age 5, 10 and 30 years (n = 11,261). Data were available on birthweight, breastfeeding; height, weight, pubertal status, socio-economic status at age 10 years; self-report data on history of diabetes (type, age at onset) at age 30 years. Cox proportional hazards models were used to examine relations of childhood growth, socio-economic status and breastfeeding history to the incidence of Type 1 diabetes between 10 and 30 years of age.

RESULTS

Sixty-one subjects (0.5%) reported Type 1 diabetes at 30 years of age; 47 (77%) reported onset >or= age 10 years. Higher BMI z-score at 10 years predicted higher risk of subsequent Type 1 diabetes (hazard ratio 1.8, 95% confidence interval 1.2 to 2.8, P = 0.01) when adjusted for birthweight, pubertal status, breastfeeding history and socio-economic status. Repeating the model for childhood obesity, the hazard ratio was 3.1 (1.0, 9.3; P = 0.05). Birthweight, breastfeeding, height growth and pubertal timing were not associated with incidence of Type 1 diabetes.

CONCLUSIONS

Higher BMI in childhood independently increased the risk of later Type 1 diabetes, supporting suggestions that obesity may provide a link between Type 1 and Type 2 diabetes. This supports observations of a rise in Type 1 diabetes prevalence. Reduction in childhood obesity may reduce the incidence of Type 1 as well as Type 2 diabetes.

A randomised study of the effect of two doses of biosynthetic human growth hormone on final height of children with familial short stature

BACKGROUND/AIMS

The effects of biosynthetic human growth hormone (r-hGH) in children with familial short stature (FSS) are varied. We determined whether responsivity to r-hGH in FSS is dose-dependent.

METHOD

Randomised trial of two doses (20 or 40 IU/m(2) body surface area/week by daily subcutaneous injection) of r-hGH in 29 (24 male, 5 female) FSS children with assessment at adult height.

RESULTS

Age range at presentation was 5.1-10.5 years, height less than 1.5 standard deviation scores (SDS) below the mean, height velocity SDS greater than -1.5 and peak growth hormone response to provocative testing over 13.5 mU/l. Adult height data (SDS) at 16.5 +/- 2.1 years for the low-dose group and 16.1 +/- 1.1 years for the high-dose group (p = 0.62) were similar [low dose -1.06 (SD 0.75), high dose -1.02 (SD 0.83); p = 0.88]. The incremental effect of both doses on stature was minimal [low-dose difference in height actual-predicted 0.79 (SD 0.94), high dose 1.27 (SD 0.88); p = 0.12].

CONCLUSION

Using this r-hGH dosing schedule there were little short- or long-term effects on height in children with FSS.

Plasma aldosterone response to the low-dose adrenocorticotrophin (ACTH 1-24) stimulation test

BACKGROUND

Endocrine tests for adrenal insufficiency use pharmacological doses of stimulant such as ACTH. More physiological tests have often used high-dose protocols for sampling frequency.

AIMS

To evaluate the response of plasma aldosterone concentration to low doses (125, 250 and 500 ng/m(2) body surface area) of synthetic ACTH.

DESIGN

A randomised trial in six normal adult males aged 18-27 years.

MATERIALS AND METHODS

Aldosterone concentration was measured by radioimmunoassay in serum from blood samples taken at 10 min intervals for 90 min.

RESULTS

All three doses produced a significant rise in plasma aldosterone concentration (125 ng/m(2), P = 0.003; 250 ng/m(2), P < 0.001; 500 ng/m(2), P < 0.001) but there was no effect of dose on either the peak or incremental plasma aldosterone concentration. Mean time to peak was similar between the doses and the two higher doses were associated with a longer secretory profile (125 ng/m(2) 56 (26 SD) mins, 250 ng/m(2) 74 (19) mins, 500 ng/m(2) 77 (21) mins; F = 3.39; P = 0.04). Peaks of 100% were detected within 30 min of drug administration and peak response was associated with the prestimulation plasma aldosterone concentration (r = 0.45; P = 0.003). The between- and within-individual coefficients of variation for prestimulation concentrations were 37.0% and 32.8%, and for the peak response were 27.2% and 27.2%, respectively.

CONCLUSIONS

The response of plasma aldosterone concentrations to low-dose ACTH administration requires a blood sampling protocol of 0, 10, 20 and 30 min to capture concentrations near the peak response. The high-dose protocol would have missed the response. Over the dose range studied no dose-response was observed so the selection of dose should be based on the dose effective to release steroids in the glucocorticoid pathway if this study is to be used in conjunction with such evaluation.

Auxological and biochemical assessment of short stature

Measurements of height and calculation of height velocity are highly accurate and sensitive to changes in a child's health. Definition of normality must be based on height velocity, and it is not acceptable to label a child as short and normal purely on the basis of a biochemical test unless this is substantiated with the demonstration of a normal height velocity. Response to therapy is dependent on the child's pretreatment growth rate and also on the amount of GH administered and the frequency of administration.

Management of neonatal endocrinopathies--best practice guidelines

Neonatal emergencies are uncommon, but may lead to significant morbidity and mortality if not recognised and managed promptly. Disorders of sex development, hypoglycaemia, thyrotoxicosis and calcium balance are discussed, with emphasis on the clinical assessment, investigations and management of these disorders in the acute setting.

A method for assessing quality of control from glucose profiles

AIM

As the practice of multiple assessments of glucose concentration throughout the day increases for people with diabetes, there is a need for an assessment of glycaemic control weighted for the clinical risks of both hypoglycaemia and hyperglycaemia.

METHODS

We have developed a methodology to report the degree of risk which a glycaemic profile represents. Fifty diabetes professionals assigned risk values to a range of 40 blood glucose concentrations. Their responses were summarised and a generic function of glycaemic risk was derived. This function was applied to patient glucose profiles to generate an integrated risk score termed the Glycaemic Risk Assessment Diabetes Equation (GRADE). The GRADE score was then reported by use of the mean value and the relative percent contribution to the weighted risk score from the hypoglycaemic, euglycaemic, hyperglycaemic range, respectively, e.g. GRADE (hypoglycaemia%, euglycaemia%, hyperglycaemia%).

RESULTS

The GRADE scores of indicative glucose profiles were as follows: continuous glucose monitoring profile non-diabetic subjects GRADE = 1.1, Type 1 diabetes continuous glucose monitoring GRADE = 8.09 (20%, 8%, 72%), Type 2 diabetes home blood glucose monitoring GRADE = 9.97 (2%, 7%, 91%).

CONCLUSIONS

The GRADE score of a glucose profile summarises the degree of risk associated with a glucose profile. Values < 5 correspond to euglycaemia. The GRADE score is simple to generate from any blood glucose profile and can be used as an adjunct to HbA1c to report the degree of risk associated with glycaemic variability.

A method for assessing quality of control from glucose profiles

AIM

As the practice of multiple assessments of glucose concentration throughout the day increases for people with diabetes, there is a need for an assessment of glycaemic control weighted for the clinical risks of both hypoglycaemia and hyperglycaemia.

METHODS

We have developed a methodology to report the degree of risk which a glycaemic profile represents. Fifty diabetes professionals assigned risk values to a range of 40 blood glucose concentrations. Their responses were summarised and a generic function of glycaemic risk was derived. This function was applied to patient glucose profiles to generate an integrated risk score termed the Glycaemic Risk Assessment Diabetes Equation (GRADE). The GRADE score was then reported by use of the mean value and the relative percent contribution to the weighted risk score from the hypoglycaemic, euglycaemic, hyperglycaemic range, respectively, e.g. GRADE (hypoglycaemia%, euglycaemia%, hyperglycaemia%).

RESULTS

The GRADE scores of indicative glucose profiles were as follows: continuous glucose monitoring profile non-diabetic subjects GRADE = 1.1, Type 1 diabetes continuous glucose monitoring GRADE = 8.09 (20%, 8%, 72%), Type 2 diabetes home blood glucose monitoring GRADE = 9.97 (2%, 7%, 91%).

CONCLUSIONS

The GRADE score of a glucose profile summarises the degree of risk associated with a glucose profile. Values < 5 correspond to euglycaemia. The GRADE score is simple to generate from any blood glucose profile and can be used as an adjunct to HbA1c to report the degree of risk associated with glycaemic variability.

Polymorphisms in the Angiotensin Converting Enzyme Gene and Growth in the First Year of Life

Abnormal patterns of fetal and infant growth have been associated with an increased risk of cardiovascular disease in adulthood. Catch-up growth during the first year of life has been associated with a higher prevalence of type 2 diabetes mellitus, whereas a lack of catch-up growth tracks with a risk of hypertension. The role of genetic factors influencing both growth and blood pressure have not been explored. We genotyped cord blood samples from 530 singleton, Caucasian, uncomplicated pregnancies, drawn from a larger cohort of 1650 pregnancies, and related polymorphism in the angiotensin converting enzyme (ACE) gene (alleles insertion (I) or deletion (D)) with measures of size at birth and at age of 1 year. ACE genotype did not significantly influence size at birth, although there was a greater proportion of individuals with the D/D genotype born with a birth weight less than the 10th centile (P=0.004). The ACE I/I genotype was significantly associated with higher weight (p=0.001), body mass index (p=0.001) and mid arm circumference (p=0.001) at 1 year of age compared to the ACE D/D and I/D genotypes. Individuals with the I/I genotype displayed catch-up (gain from birth size of >or=0.6 Standard Deviation Score) in weight (p=0.04), body mass index (p=0.03) and mid arm circumference (p=0.03) compared to the D/D group, the majority of which showed no change or catch-down. The I/D genotype was distributed equally across the catch up/catch down/no change categories. The effect was more marked in males, but ACE genotype and sex of the infant contributed independently to mid arm circumference measurements and there was no interaction between the two. There was no effect of maternal or paternal ACE genotype on birth size. In a multiple linear regression model ACE genotype, socioeconomic status and sex of the infant explained 10.9% of the variance in body mass index SDS at 1 year of age. We conclude that the ACE I/I genotype is associated with a higher weight and body mass index SDS at 1 year of age, along with catch-up in terms of these measures from birth to 1 year. The D/D genotype is associated with a greater proportion of babies, born at term, that at small for gestational age. These results suggest that due consideration should be given to the underlying genotype of an individual when evaluating the association of early human growth with the development of risk factors for cardiovascular disease. The observation of independent effects of genotype, sex of the individual and socioeconomic status on postnatal growth suggests the need to develop methodologies for the integration of genetic and environmental factors in causality modelling.

Normal and abnormal fetal growth

The fetal origins of adult disease hypothesis suggests that poor intrauterine growth is associated with an increased risk of cardiovascular disease. The hypothesis goes on to implicate different growth 'phenotypes', particularly disproportionate growth, in the determination of the type of cardiovascular disease that develops. Analysis of the antenatal growth of a low-risk pregnancy population does not identify such growth phenotypes within the general population. Rather, intrauterine growth is characterized by poor predictability of subsequent size, suggesting that centile crossing is a common feature of intrauterine growth. Furthermore, there is a sexually dimorphic pattern to this growth that needs to be considered in further work to test the fetal origins hypothesis.

The impact of hormone physiology on clinical practice with reference to two papers spanning 40 years of endocrinology

Following the pioneering work of Roger Ekins in describing the methodology for radioimmunoassay of hormone concentrations in plasma a series of publications followed describing variation in plasma hormone concentrations in a number of diseases. Though fluctuations in hormonal concentrations had been suspected, it was not until Hunter and Rigal documented these for the GH axis that it became apparent that the preferred mode of signalling for many hormone systems and in particular the anterior-pituitary hormones was of a pulsatile nature.

Disturbed adrenal function in adolescents with chronic fatigue syndrome

OBJECTIVE

To investigate adrenal function in children and adolescents with chronic fatigue syndrome (CFS) compared with age-matched controls.

METHODS

Case-control study of low dose (500 ng/m2) synacthen tests (LDST) in 23 adolescents with CFS and 17 age-matched controls. Serum cortisol concentrations were measured at 5-min intervals from 10 to 45 minutes. Peak serum cortisol concentration, time to peak, rise in cortisol and area under the curve (AUC) were derived.

RESULTS

Patients with CFS had significantly lower mean cortisol levels during the LDST (p <0.001), lower peak cortisol (p <0.025), reduced cortisol AUC (p <0.005) and longer time to peak cortisol (p <0.05). Abnormalities were seen in both sexes but were more pronounced in females. Unstimulated adrenal androgen and 17-hydroxyprogesterone concentrations were normal.

CONCLUSIONS

Adolescents with CFS have subtle alterations in adrenal function suggesting a reduction in central stimulation of the adrenal glands. The more pronounced effects in females may reflect differential central effects of stress on hypothalamic-pituitary-adrenal axis regulation between the sexes.

Growth hormone (GH) provocation tests and the response to GH treatment in GH deficiency

OBJECTIVE

To identify factors, particularly the growth hormone (GH) provocation test result, affecting growth response to GH treatment in children with GH deficiency (GHD).

SUBJECTS

A total of 337 prepubertal GHD patients aged <10 years from the UK Pharmacia KIGS database (GH response to provocation test <20 mU/l).

OUTCOME MEASURE

Annual change in height standard deviation score (SDS) (revised UK reference) in the first and second years of treatment.

RESULTS

Height increased by 0.74 SDS units (SD 0.39) in the first year of treatment and 0.37 units (SD 0.27) in the second. Adjusting for age, height, weight, midparent height, and injection frequency, the strongest predictor of first year growth response was the GH provocation test result; halving the result predicted an extra height increment of 0.09 units (p<0.0001). It predicted the second year response less well (p<0.0002) and after adjusting for the first year response was not predictive at all.

CONCLUSIONS

Among patients referred for possible GHD, the GH provocation test, though not a gold standard for diagnosis, is a valuable predictor of growth response in the first year of treatment. A year's treatment is recommended for cases with a marginal provocation test result, with the option to continue treatment if the response is adequate. The value of unified protocols for single or repeated provocation tests needs to be assessed.

Clinical features, diagnosis, treatment and molecular studies in paediatric Cushing's syndrome due to primary nodular adrenocortical hyperplasia

BACKGROUND

Primary nodular adrenocortical hyperplasia (PNAH) is a well recognized, but infrequently studied cause of paediatric Cushing's syndrome (CS).

OBJECTIVE

To assess presentation, diagnosis, radiological imaging, treatment and molecular analysis of patients with childhood-onset CS due to PNAH.

PATIENTS

Four males and two females (median age 12.9 years, range 10.9-16.9 years) were studied.

RESULTS

All had growth failure (mean height SDS -1.2; range -2.5-0.0), weight gain [mean body mass index (BMI) SDS 3.5; range 2.5-4.6] and clinical virilization, while five had hypertension [mean systolic blood pressure (SBP) 130 mmHg, diastolic blood pressure (DBP) 83 mmHg]. One patient had generalized lentigines, one had a tibial chondromyxomatous cyst and two had facial freckling. One patient had a family history of primary nodular adrenocortical disease. The diagnosis of CS was based on elevation of sleeping midnight serum cortisol and urinary free cortisol excretion, and impaired suppression of cortisol on both low- and high-dose dexamethasone suppression tests (DST). All patients had undetectable plasma ACTH with absent responses of both plasma ACTH and serum cortisol to an intravenous (i.v.) corticotrophin-releasing hormone (CRH) test. Computed tomography or magnetic resonance imaging showed normal or small adrenals, with nodules in two patients. All patients underwent bilateral adrenalectomy, performed by open (n = 2) or laparoscopic surgery (n = 4) at a mean of 0.4 years (range 0.2-0.8 years) from diagnosis. Hypercortisolaemia was treated preoperatively by metyrapone alone 0.50-0.75 g/day (n = 4), metyrapone 0.75-1.50 g/day + o'p'DDD/mitotane 1-2 g/day (n = 1), or ketoconazole (n = 1). Adrenal histology showed nodular cortical hyperplasia with shrinkage of intervening cortical tissue and pigmentation, present in four patients. Molecular analysis of the type 1-alpha regulatory subunit of protein kinase A (PRKAR1A) gene revealed a novel germline mutation in one patient. Postadrenalectomy, three patients, had catch-up growth with height velocities increasing from 3.0, 3.9 and 2.5-8.9, 8.3 and 9.0 cm/years, respectively. All six are well at a follow-up (mean 4.0 years; range 0.5-10.8 years).

CONCLUSIONS

PNAH was associated with cushingoid features, virilization and hypertension with a lack of cortisol suppression on high DST, undetectable plasma ACTH and absent cortisol and ACTH responses to CRH. Adrenals were normal or small on imaging. PRKAR1A gene analysis may be helpful in the assessment of these patients.

Sexual dimorphism in the synchrony of joint growth hormone and cortisol dynamics in children with classic 21-hydroxylase deficiency

In humans, growth hormone (GH) and cortisol are secreted in a pulsatile fashion and a mutual bidirectional interaction between the GH/insulin-like growth factor (IGF)-I axis and hypothalamic-pituitary-adrenal (HPA) axis has been established. Classic congenital adrenal hyperplasia (CAH) is characterized by a defect in the synthesis of glucocorticoids and often mineralocorticoids, and adrenal hyperandrogenism. In view of the sexually dimorphic pattern in GH secretion, we investigated the GH-cortisol bihormonal secretory dynamics in male and female children with classic CAH. Thirty-eight children with classic 21-hydroxylase deficiency (M: 13, F: 25; age range: 6.1-18.8 yr) were studied prospectively. Serum GH and cortisol concentrations were determined at 20 min intervals for 24 hours. The irregularity of GH and cortisol pattern was assessed using approximate entropy (ApEn), a scale- and model-independent statistic. The synchrony of joint GH-cortisol dynamics was quantified using the cross-ApEn statistic. Cross-correlation analysis of GH and cortisol concentrations was computed at various time lags covering the 24-h period. There was no gender difference in mean 24-hour serum GH (males vs females: 5.25 +/- 4.72 vs 4.44 +/- 2.64 mIU/l) or cortisol (156.2 +/- 44.6 vs 172.0 +/- 58.5 nmol/l) concentrations. For GH, ApEn values were significantly higher in females (0.66 +/- 0.14) than in males (0.53 +/- 0.16) (p = 0.009). No difference in cortisol ApEn values was noted between sexes (0.53 +/- 0.21 vs 0.54 +/- 0.12). Cross-ApEn values of paired GH-cortisol, with cortisol leading GH, were significantly higher in females (0.94 +/- 0.14) than in males (0.83 +/- 0.20) (p = 0.03). These findings suggest that females with classic 21-hydroxylase deficiency have a more irregular pattern of GH secretion and a more asynchronous joint GH and cortisol dynamics than their male counterparts.

Growth hormone predicts bone density in elderly women

Evidence is accumulating that the risk of osteoporosis may be influenced by environmental factors during intrauterine and early postnatal life; such programming might be mediated through modification of the GH/IGF-1 axis during critical periods in its development. To address this issue, we explored the relationships among birth weight, circulating GH profile, bone density, and bone loss rate in a group of British women. The study population consisted of 38 women 60-75 years old resident in Hertfordshire for whom detailed birth records were available. Twenty-four-hour circulating GH profiles were obtained during an inpatient stay on a metabolic ward, after an overnight rest. The circulating profile of GH was characterised by estimating the peak, median, trough, and total concentrations from 72 samples measured sequentially over 24 h in each subject. Bone mineral density was assessed at the lumbar spine and femoral neck at baseline and at follow-up 4 years later. Lumbar spine bone mineral content (BMC) and density (BMD) were positively associated with all measures of GH concentration, although relationships were strongest for BMC with trough GH (r = 0.47, P < 0.01). Associations persisted after adjustment for age, body mass index, smoking, alcohol consumption, physical activity, and osteoarthritis score in multiple regression models. However, associations of GH concentration with femoral neck BMC were weak, and there was no association between any measure of GH concentration and bone loss at either site. Total (integrated) daily GH concentration tended to increase (P = 0.08) with rising birth weight, while IGF-1 concentration fell (P = 0.05) with rising birth weight, suggesting a role for the GH/IGF-1 axis in the programming of adult bone mass among women.

17-Hydroxylase/17,20 lyase deficiency diagnosed during childhood

We present a case of familial 17alpha-hydroxylase/17,20 lyase (CYP17) deficiency in which the index case, a 14-year-old XX girl, led to the diagnosis of the condition in a 9-year-old XY sister. No mutations in the CYP 17 gene were found in any of the girls.

Kinetics and effect of percutaneous administration of dihydrotestosterone in children

BACKGROUND

Percutaneous administration of dihydrotestosterone (DHT) has been successful in promoting phallic growth in infants and children with 5 alpha-reductase deficiency raised as males. We investigated whether percutaneous administration of DHT is similarly effective in patients with micropenis due to alternative diagnoses.

METHODS

Six patients (age range 1.9-8.3 years) with micropenis of variable etiology were studied prospectively. 2.5% DHT gel was applied to the phallus once daily at a dose of 0.15-0.33 mg/kg body weight. Serum DHT concentrations were measured at 0, 2, 4, 8, 12 and 24 h following application of DHT gel.

RESULTS

Peak DHT concentrations were attained within 2-8 h after application of the gel and subsequently remained within the normal adult range in all but 1 patient, who had received the lowest dose of 0.15 mg/kg. An increase in phallic growth, ranging from 0.5-2.0 cm, was achieved after 3-4 months of treatment in all patients whose DHT concentrations were maintained within adult range.

CONCLUSION

Percutaneous administration of DHT in a dose of 0.2-0.3 mg/kg once daily for a period of 3-4 months may be useful in the management of patients with testosterone biosynthetic defects, who have sufficient masculinization to warrant male sex assignment, or in patients with micropenis prior to reconstructive surgery.

Why is management of patients with classical congenital adrenal hyperplasia more difficult at puberty?

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is an autosomal recessive condition in which deletions or mutations of the cytochrome P450 21-hydroxylase gene cause glucocorticoid and often mineralocorticoid deficiency. Despite optimal substitution therapy, control of classical CAH is often inadequate at puberty, and the problems encountered relate to hypocortisolism and/or hyperandrogenism. A number of physiological alterations in the endocrine milieu at puberty, which include alterations in the growth hormone/insulin-like growth factor axis, insulin sensitivity, as well as the activity of enzymes participating in cortisol metabolism and adrenal steroidogenesis, may account for the documented hypocortisolism and elevated androgen production, and may explain the difficulty in maintaining adequate adrenocortical suppression in pubertal patients with classical 21-hydroxylase deficiency.

Treatment with flutamide decreases cortisol clearance: implications for therapy in congenital adrenal hyperplasia

BACKGROUND

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is characterized by a defect in cortisol and often aldosterone secretion, and adrenal hyperandrogenism. Current treatment is to provide adequate glucocorticoid and mineralocorticoid substitution to prevent adrenal crises and to suppress excess adrenocortical androgen secretion. Anti-androgen therapy with flutamide is an option that allows control of hyperandrogenism without recourse to supraphysiological doses of glucocorticoid.

METHODS

We examined the pharmacokinetic parameters of hydrocortisone administered i.v. as a bolus at a dose of 15 mg/m2 in a 17.3 year-old female patient with classic CAH before and four weeks after institution of flutamide treatment by determining serum cortisol concentrations at 10 min intervals for 6 h following the i.v. bolus of hydrocortisone.

RESULTS

Treatment with flutamide resulted in a decrease in cortisol clearance from 420 ml/l to 305 ml/l (27% reduction), and a decrease in volume of distribution from 51.61 to 451 (12.9% reduction). The half-life of cortisol increased from 85.3 min to 102.1 min.

CONCLUSIONS

Flutamide treatment decreases cortisol clearance, thereby prolonging its half-life. These findings indicate that a reduction in the daily dose of glucocorticoid replacement may need to be considered when flutamide is added to the treatment regimen of patients receiving hydrocortisone.

Serum cortisol and 17-hydroxyprogesterone interrelation in classic 21-hydroxylase deficiency: is current replacement therapy satisfactory?

One of the main aims in the management of patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency is to achieve adequate suppression of the adrenal cortex with the smallest possible dose of glucocorticoid substitution. To evaluate the administration schedule of current replacement therapy regimens, we investigated the cortisol-17-hydroxyprogesterone interrelation in 36 patients (13 males and 23 females; median age, 12.3 yr; range, 6.1-18.8 yr) with salt-wasting congenital adrenal hyperplasia. As sufficient variation in 17-hydroxyprogesterone concentrations was required to allow analysis of the cortisol-17-hydroxyprogesterone interrelation, patients were divided into 2 groups depending on the adequacy of hypothalamic-pituitary-adrenal axis suppression. The first group consisted of 17 patients with suppressed 17-hydroxyprogesterone concentrations (group 1), and the second group consisted of 19 patients with nonsuppressed 17-hydroxyprogesterone concentrations (group 2). We determined serum cortisol and 17-hydroxyprogesterone concentrations at 20-min intervals for a total of 24 h while patients were receiving their usual replacement treatment with hydrocortisone and 9alpha-fludrocortisone. We also determined the lowest dose of dexamethasone required to suppress the 0800 h serum ACTH concentrations when administered as a single dose (0.3 or 0.5 mg/m(2)) the night before. Mean 24-h cortisol and 17-hydroxyprogesterone concentrations were 3.9 microg/dl (SD = 2.1) and 66.2 ng/dl (SD = 92.7), respectively, in group 1 and 4.1 microg/dl (SD = 2.5) and 4865.7 ng/dl (SD = 6951) in group 2. The 24-h 17-hydroxyprogesterone concentrations demonstrated circadian variation, with peak values observed between 0400-0900 h. In group 2, 17-hydroxyprogesterone concentrations decreased gradually in response to the rise in cortisol concentrations during the day, but remained low during the night despite the almost undetectable cortisol concentrations between 1600-2000 h. Mean 0800 h androstenedione concentrations correlated strongly with integrated 17-hydroxyprogesterone concentrations (r = 0.81; P < 0.0001), but not with integrated cortisol concentrations. There was a significant negative correlation between cortisol and 17-hydroxyprogesterone at lag time 0 min (r = -0.187; P < 0.0001), peaking at lag time 60 min (r = -0.302; P < 0.0001), with cortisol leading 17-hydroxyprogesterone by these time intervals. Finally, 0800 h serum ACTH concentrations were sufficiently suppressed after a dexamethasone dose of 0.3 mg/m(2) in all but three patients. These findings indicate that in classic 21-hydroxylase deficiency, hydrocortisone should be administered during the period of increased hypothalamic-pituitary-adrenal axis activity, between 0400-1600 h, with the biggest dose given in the morning. Blood investigations performed as part of monitoring of congenital adrenal hyperplasia patients should include androstenedione and 17-hydroxyprogesterone concentrations determined in the morning before the administration of hydrocortisone. It should also be emphasized that blood investigations are only complementary to the overall assessment of these patients, which is primarily based on the evaluation of growth and pubertal progress.

Congenital adrenal hyperplasia: management during critical illness

BACKGROUND

Little is known of the optimal dose and administration schedule of hydrocortisone in critically ill patients with congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency.

AIM

To determine plasma cortisol concentrations after intravenous administration of hydrocortisone in children with CAH and to relate these to plasma cortisol concentrations achieved by endogenous secretion in the stress of critical illness in previously healthy children.

METHODS

Plasma cortisol concentrations were measured in 20 patients with classical CAH (median age 11.2 years, range 6.1-16.4) following intravenous administration of hydrocortisone 15 mg/m(2); and in 60 critically ill mechanically ventilated children (median age 2.5 years, range 0.25-16.3) on admission to the paediatric intensive care unit and for 24 hours thereafter.

RESULTS

In the CAH patients, plasma cortisol reached a mean peak of 1648.3 nmol/l (SD 511.9) within 10 minutes of the intravenous bolus, and fell rapidly thereafter; levels remained greater than 450 nmol/l for 2.5 hours only. In critically ill children, mean plasma cortisol on admission to the intensive care unit was 727 nmol/l (SD 426.1). Cortisol concentrations remained raised during the first 24 hours.

CONCLUSIONS

Critically ill patients with classical CAH may be best managed with a single intravenous hydrocortisone bolus followed by a constant rate infusion of hydrocortisone.

Joint growth hormone and cortisol spontaneous secretion is more asynchronous in older females than in their male counterparts

In humans, cortisol and GH are secreted in a pulsatile manner, and an interaction between GH and the hypothalamic-pituitary-adrenal axis has been established. In view of the sexually dimorphic pattern in GH secretion, we investigated the GH-cortisol bihormonal secretory dynamics in male and female healthy older individuals. We studied the GH and cortisol secretory patterns in 83 healthy subjects (45 men and 38 women; age range, 59.4-73.0 yr) by determining serum GH and cortisol concentrations at 20-min intervals for 24 h. The irregularity of GH and cortisol secretion was assessed using approximate entropy (ApEn), a scale- and model-independent statistic. The synchrony of joint GH-cortisol spontaneous secretion was quantified using the cross-ApEn statistic. Cross-correlation analysis of GH and cortisol patterns was computed at various time lags covering the 24-h period. Mean 24-h serum GH concentrations were significantly higher in females (mean, 1.31 mU/L; SD, 0.87) than in males (mean, 0.88 mU/L; SD, 0.42; P = 0.009), whereas mean 24-h serum total cortisol concentrations were higher in males (mean, 9.0 microg/dL; SD, 1.4) than in females (mean, 7.3 microg/dL; SD, 1.4; P = 0.0001). GH secretion was more irregular in females (mean ApEn, 0.81; SD, 0.23) than in males (mean ApEn, 0.60; SD, 0.20; P < 0.001). No significant difference in the regularity of cortisol secretion was noted between sexes. Cross-ApEn values of paired GH-cortisol were higher in females (mean, 1.15; SD, 0.18) than in males (mean, 1.01; SD, 0.16; P = 0.0003). Stepwise multiple linear regression analysis indicated that estradiol and insulin-like growth factor-binding protein-3 concentrations were independently related to GH ApEn values (r(2) = 0.14; P = 0.01), whereas cross-ApEn values of paired GH-cortisol were best predicted by FSH concentrations (r(2) = 0.37; P = 0.003). Cross-correlation analysis revealed a significant positive correlation between GH and cortisol, peaking at lag time of 4.7 h in males (r = 0.30; P < 0.0001) and 4.3 h in females (r = 0.14; P < 0.0001), with GH leading cortisol by these time intervals. In addition, a significant negative correlation between the two hormones was noted over time, peaking at 4.7 h in males (r = -0.21; P < 0.0001) and 6.3 h in females (r = -0.25; P < 0.0001), with cortisol leading GH by these time intervals. The above results indicate that in the elderly, females have a more disordered GH secretory pattern and a more asynchronous joint GH-cortisol secretion than their male counterparts. These observations most likely reflect bidirectional interactions between the GH and hypothalamic-pituitary-adrenal axis in humans as well as diminution of subsystem integrity and synchronous control of interconnected hormonal systems with advancing age.

Congenital adrenal hyperplasia due to 21-hydroxylase deficiency: alterations in cortisol pharmacokinetics at puberty

In congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, treatment with glucocorticoid and mineralocorticoid substitution is not always satisfactory. Suboptimal control is often observed in pubertal patients, despite adequate replacement doses and adherence to treatment. We investigated whether the pubertal process is associated with alterations in cortisol pharmacokinetics resulting in a loss of control of the hypothalamic-pituitary-adrenal axis. We determined the pharmacokinetics of hydrocortisone administered iv as a bolus. A dose of 15 mg/m(2) body surface area was given to 14 prepubertal (median age, 9.4 yr; range, 6.1--10.8 yr), 20 pubertal (median, 13.5 yr; range, 10.6--16.8 yr), and 6 postpubertal (median, 18.2 yr; range, 17.2--20.3 yr) patients with salt-wasting CAH. All patients were on standard replacement therapy with hydrocortisone and 9 alpha-fludrocortisone. Serum total cortisol concentrations were measured at 10-min intervals for 6 h following iv hydrocortisone bolus and analyzed using a solid-phase RIA. The serum total cortisol clearance curve was monoexponential. Mean clearance was significantly higher in the pubertal group (mean, 427.0 mL/min; SD, 133.4) compared with the prepubertal (mean, 248.7 mL/min; SD, 100.6) and postpubertal (mean, 292.4 mL/min; SD, 106.3) (one-way ANOVA, F = 9.8, P < 0.001) groups. This effect persisted after adjustment for body mass index. The mean volume of distribution was also significantly higher in the pubertal (mean, 49.5 L; SD, 12.2) than the prepubertal (mean, 27.1 L; SD, 8.4) patients but not in the postpubertal (mean, 40.8 L; SD, 16) (ANOVA, F = 15.2, P < 0.001) patients. The significance remained after correction for body mass index. There was no significant difference in mean half-life of total cortisol in prepubertal (mean, 80.2 min; SD, 19.4), pubertal (mean, 84.4 min; SD, 24.9), and postpubertal (mean, 96.7 min; SD, 9.9) patients. Similar differences between groups were observed when the pharmacokinetic parameters of free cortisol were examined. In addition, the half-life of free cortisol was significantly shorter in females compared with males (P = 0.04). These data suggest that puberty is associated with alterations in cortisol pharmacokinetics resulting in increased clearance and volume of distribution with no change in half-life. These alterations probably reflect changes in the endocrine milieu at puberty and may have implications for therapy of CAH and other conditions requiring cortisol substitution in the adolescent years.

Bioavailability of oral hydrocortisone in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

The management of congenital adrenal hyperplasia due to 21-hydroxylase (CYP21) deficiency requires glucocorticoid substitution with oral hydrocortisone given twice or thrice daily. In paediatric practice little is known of the bioavailability of oral hydrocortisone tablets used in these patients. The aim of this study was to assess the bioavailability of oral hydrocortisone and to evaluate current replacement therapy in the light of cortisol pharmacokinetic properties. We determined the bioavailability of hydrocortisone following oral and intravenous administration in sixteen (median age: 10.9 years, range: 6.0-18.4 years) adequately controlled CYP21 deficient patients. Serum total cortisol concentrations were measured at 20-min intervals for 24 h while patients were on oral substitution therapy, and at 10-min intervals for 6 h following an intravenous bolus of hydrocortisone in a dose of 15 mg/m(2) body surface area. The area under the serum total cortisol concentration versus time curve (AUC) following oral and intravenous administration of hydrocortisone was calculated using the trapezoid method. The bioavailability was estimated by dividing the corrected for dose AUC after oral hydrocortisone administration by the corrected for dose AUC after the intravenous hydrocortisone administration and was exemplified as a percentage. After oral administration of hydrocortisone in the morning, median serum total cortisol concentrations reached a peak of 729.5 nmol/l (range: 492-2520 nmol/l) at 1.2 h (range: 0.3-3.3 h) and declined monoexponentially thereafter to reach undetectable concentrations 7 h (range: 5-12 h) after administration. Following administration of the evening hydrocortisone dose, median peak cortisol concentration of 499 nmol/l (range: 333-736 nmol/l) was attained also at 1.2 h (range: 0.3-3.0 h) and subsequently declined gradually, reaching undetectable concentrations at 9 h (5-12 h) after administration of the oral dose. After the intravenous hydrocortisone bolus a median peak serum total cortisol concentration of 1930 nmol/l (range: 1124-2700 nmol/l) was observed at 10 min (range: 10-20 min). Serum cortisol concentrations fell rapidly and reached undetectable levels 6 h after the hydrocortisone bolus. The absolute bioavailability of oral hydrocortisone in the morning was 94.2% (90% confidence interval (CI): 82.8-105.5%) whereas the apparent bioavailability in the evening was estimated to be 128.0% (90% CI: 119.0-138.0%). We conclude that the bioavailability of oral hydrocortisone is high and may result in supraphysiological cortisol concentrations within 1-2 h after administration of high doses. The even higher bioavailability in the evening, estimated using as reference the data derived from the intravenous administration of hydrocortisone bolus in the morning, is likely to reflect a decrease in the hydrocortisone clearance in the evening. Decisions on the schedule and frequency of administration in patients with congenital adrenal hyperplasia should be based on the knowledge of the bioavailability and other pharmacokinetic parameters of the hydrocortisone formulations currently available.

Molecular genetics of septo-optic dysplasia

Septo-optic dysplasia (SOD) is a highly variable condition characterized by midline neurological abnormalities associated with pituitary hypoplasia and optic nerve hypoplasia. The aetiology is unknown. Mutant mice, in which a novel homeobox gene, Hesx1, has been disrupted, exhibit a phenotype that resembles the phenotype of SOD. We therefore wished to explore the possibility that this gene is implicated in SOD. We cloned and sequenced the human homologue HESX1 and screened for mutations in affected individuals using single-stranded conformational polymorphism analysis, followed by cloning and sequencing of any exons which showed a band shift. Two siblings with SOD were homozygous for an Arg53Cys missense mutation within the HESX1 homeodomain, leading to a loss of in vitro DNA binding. Subsequently, we have identified heterozygous mutations in HESX1 that are associated with milder pituitary phenotypes. Our studies indicate a vital role for Hesx1/HESX1 in forebrain and pituitary development in mouse and man, and hence in some cases of SOD.

Performance of a new pubertal self-assessment questionnaire: a preliminary study

We describe the performance of a new, self-assessment questionnaire that aims to measure pubertal status by using gender-specific line drawings of the Tanner puberty stages. The study was carried out on 103 children aged 12-16 years attending a paediatric endocrinology outpatient clinic and used physical examination by clinic doctors as the 'gold standard'. Of 133 consecutive, eligible children, 108 (81%) agreed to participate in the study. Data were collected from 62 (60%) males and 41 (40%) females. Mean age was 14.78 years (SD = 1.26 years, range 12.08-16.98 years). For the pubic hair distribution Tanner stage, there was agreement to within one Tanner stage for 90 children (88%), weighted kappa statistic for inter-rater agreement = 0.68 [95% CI 0.49,0.87]. For the female breast/male genitalia Tanner stage, there was agreement to within one Tanner stage for 75 children (76%), kappa = 0.48 [95% CI 0.31,0.64]. The children tended to underestimate their stage of pubertal development. Overall, the kappa statistics implied good agreement for the pubic hair question and moderate agreement for the breast/genitalia stage question in both girls and boys. The questionnaire may prove useful in situations such as large-scale epidemiological studies, in which direct examination of children to determine pubertal status is not possible, and further validation in normal adolescents is warranted.

Growth hormone treatment of children with brain tumors and risk of tumor recurrence

GH is increasingly used for treatment of children and adults. It is mitogenic, however, and there is therefore concern about its safety, especially when used to treat cancer patients who have become GH deficient after cranial radiotherapy. We followed 180 children with brain tumors attending three large hospitals in the United Kingdom and treated with GH during 1965-1996, and 891 children with brain tumors at these hospitals who received radiotherapy but not GH. Thirty-five first recurrences occurred in the GH-treated children and 434 in the untreated children. The relative risk of first recurrence in GH-treated compared with untreated patients, adjusted for potentially confounding prognostic variables, was decreased (0. 6; 95% confidence interval, 0.4-0.9) as was the relative risk of mortality (0.5; 95% confidence interval, 0.3-0.8). There was no significant trend in relative risk of recurrence with cumulative time for which GH treatment had been given or with time elapsed since this treatment started. The relative risk of mortality increased significantly with time since first GH treatment. The results, based on much larger numbers than previous studies, suggest that GH does not increase the risk of recurrence of childhood brain tumors, although the rising trend in mortality relative risks with longer follow-up indicates the need for continued surveillance.

Effect of early maternal iron stores on placental weight and structure

BACKGROUND

Large placental size and low birthweight have been implicated as factors predicting high blood pressure in adulthood. Maternal anaemia has been suggested as a link. We investigated the interaction between maternal iron status and other factors known to influence birthweight and placental size.

METHODS

In a prospective study of 1650 low-risk, singleton, caucasian pregnancies, we related placental size and birthweight to maternal iron status, socioeconomic status, and parity. Placental morphology was assessed in 17 randomly chosen primigravid pregnancies.

FINDINGS

Parity was an important determinant of birthweight (mean standard deviation score -0.13 [SD 0.90] para 0; -0.24 [0.90] para 1; 0.32 [1.1] para 2; 0.21 [1.1] para > or = 3; p<0.0001) and placental weight (mean 655 g [SD 130]; 679 g [122]; 675 g [139]; 694 g [157], respectively; p=0.01). Cigarette smoking influenced birthweight only. Socioeconomic status had little effect after correction for parity. In addition to parity, the factors influencing placental weight were maternal height, weight, and serum ferritin concentration at booking, but not haemoglobin concentration. Serum ferritin concentrations were associated with folate intake and parity. In the placental morphology subset, serum ferritin concentration was inversely related to overall measures of peripheral villous capillarization. Haemoglobin concentration showed no such association.

INTERPRETATION

These findings show a relation between maternal anaemia and placental size and birthweight across the normal range for these measures. Low ferritin concentrations in early pregnancy were associated with increased placental vascularisation at term. The association between ferritin concentration and folate supplementation emphasises the importance of preconceptional health, particularly in women at high risk of iron deficiency.

Urinary GH and IGF-I excretion in nine year-old children: relation to sex, current size and size at birth

OBJECTIVES

To study the relationship of 24-hour urinary growth hormone (GH) and IGF-I excretion in childhood to sex and body size. To test the hypothesis that small size at birth followed by postnatal catch-up growth is associated with elevated IGF-I production.

DESIGN AND SUBJECTS

Follow-up study of a cohort of 183 healthy children born in Salisbury, UK.

MEASUREMENTS

Weight and height, 24-h urinary growth hormone (uGH) and IGF-I (uIGF-I) excretion, and systolic and diastolic blood pressures.

RESULTS

At 9 years of age, 24-h uIGF-I excretion, but not uGH excretion, was strongly related to current weight (P < 0.001) and height (P < 0. 001). Urinary GH and IGF-I excretion were positively correlated (r = 0.15, P = 0.05). Boys excreted more uIGF-I per unit uGH than girls (uIGF-I/uGH molar ratio 32.1 compared to 21.0; P for difference = 0. 002). There were no significant relationships of uGH, uIGF-I or uIGF-I/uGH molar ratio with birthweight, birthlength or head circumference at birth, nor with blood pressure at 9 years. 'Catch-up' growth, indicated by an increase in height SD scores between birth and 9 years, was associated with higher IGF-I excretion (P = 0.01) and occurred in children with taller parents (P < 0.001).

CONCLUSIONS

Boys appear to be more sensitive to GH than girls, generating more uIGF-I in relation to uGH. Urinary IGF-I excretion at 9 years is related to both absolute height and to the degree of catch-up in height from birth. Our results suggest that IGF-I production is strongly influenced by genetic factors, but also by either the degree to which intrauterine growth falls short of genetic growth potential, or the process of postnatal catch-up growth that follows.

Compliance with growth hormone treatment - is it a problem?

Treatments fail for a number of reasons. These include the failure of medicines at a molecular level, failure to achieve the correct diagnosis and therefore use of the correct medication, problems surrounding the doctor-patient relationship, and failure of the service to meet patients' expectations. Compliance is characteristically viewed as the major cause of treatment failures but implicit in the use of the term compliance is the reliance on an imbalance of power where the patient follows what is ordered. Such an approach is likely to lead to failure. A better model is concerned with promoting the full participation of the patient to generate a therapeutic alliance. Despite the need for parental administration and a daily therapeutic regimen there appears to be little evidence to suggest that concordance is a major problem in growth hormone therapy. This is probably because treatment administration relies on the presence of a carer and there are tangible effects. However, concordance is likely to be an issue where there is mismatch between the patient's expectations and those of the doctor. Such a situation may arise when the therapeutic margin is narrow or the therapeutic effect minimal. To resolve this situation, adequate pre-intervention discussion is essential, which should include a clear statement of short- and long-term treatment targets and the likelihood of these being achieved or not. Carefully constructed health care plans are the key and should include educational programmes, home support and regular reinforcement. When concordance problems are suspected, careful consideration needs to be given as to whether the diagnosis is correct, is the treatment really effective and appropriate and does the patient really want the treatment.

Frasier syndrome, part of the Denys Drash continuum or simply a WT1 gene associated disorder of intersex and nephropathy?

Dysfunction of the Wilms' Tumour gene (WT1), a transcription factor critical for normal development and function of the urogenital tract, can result in both tumourigenesis [corrected] and urogenital abnormalities. The association of WT1 gene mutations with most cases of Denys-Drash syndrome is well described. More recently WT1 mutations have also been described in a related condition, Frasier syndrome. We report a case where genetic analysis showed a WT1 mutation typically associated with Frasier syndrome: a 1228 + 5 guanine to adenine substitution at the 3' alternative splice donor site in intron 9. The case provides a focus for the discussion of recent evidence that Denys Drash and Frasier syndrome form two ends of a spectrum of disorders. In addition, it illustrates the increasing significance of genetic investigation within clinical practice for diagnostic, prognostic and therapeutic purposes and the importance of karyotype analysis in phenotypically normal girls with renal disease.

The GH response to low-dose bolus growth hormone-releasing hormone (GHRH(1-29)NH2) is attenuated in patients with longstanding post-irradiation GH insufficiency

OBJECTIVE

Previous studies have suggested that post-irradiation GH insufficiency results from a loss of GHRH secretion, since many patients were able to release GH following exogenous GHRH stimulation. However, supramaximal doses of GHRH were used and the response may decline with time after radiotherapy. We re-evaluated the GHRH dose-response curve in patients post cranial irradiation and in controls.

DESIGN

Randomized controlled study.

METHODS

Five adult male long-term survivors of childhood brain tumours (median age 21.8 years (18.4-26.7); 13.7 years (11.4-15.7) post-radiotherapy, >30Gy) and five matched controls were studied. An intravenous bolus of GHRH(1-29)NH(2) was administered in doses at the lower (0.05 microg/kg) and upper (0.15 microg/kg) range of the dose-response curves for young males, as well as the standard supramaximal dose (1. 0 microg/kg). GH was measured before stimulation, every 2min for the first hour and every 5min for the second hour. All studies were conducted in a random fashion.

RESULTS

Significantly lower peak and area under the curve (AUC) GH concentrations occurred in the irradiated group using 0.15 microg/kg (median peak Irradiated, 4. 5mU/l vs median Controls, 37.4mU/l; P<0.01) and 1.0 microg/kg (median peak Irradiated, 4.8mU/l vs median Controls, 15.2mU/l; P<0. 05) GHRH(1-29)NH(2). In irradiated subjects there was an incremental rise in GH output with increasing doses of GHRH(1-29)NH(2 )(median AUC: 122mU/l.min vs 179mU/l.min vs 268mU/l.min; P=0.007) reflecting altered pituitary sensitivity and reduced responsiveness.

CONCLUSION

The GH response to bolus GHRH(1-29)NH(2) is attenuated in adult long-term survivors of childhood brain tumours. This may reflect direct pituitary damage and/or the loss of the tropic effects of chronic GHRH deficiency.

Blood pressure and Turner syndrome

INTRODUCTION

Elevated blood pressure (BP) is an important predictor of morbidity and mortality from cardiovascular disease. Patients with Turner syndrome (TS) have a higher morbidity and mortality in middle age than the normal population. As BP in childhood or early adulthood is predictive of BP later in adult life, we assessed manual and 24 h ambulatory BP in patients with TS to determine whether the BP pattern is altered at an early stage in these patients who are known to be at risk of cardiovascular disease.

PATIENTS AND METHODS

We studied manual and 24 h ambulatory BP profiles in 75 girls with Turner syndrome, age range 5.4-22.4 years. A monitor with an oscillometric device (SpaceLabs model 90207) and an appropriate sized cuff was used. BP was measured during the day-time (0800-2000 h) and the night-time periods (2200-0800 h). The BP measured were compared with population standards. The effect of different growth promoting agents on BP was also evaluated.

RESULTS

Mean manual and 24 h ambulatory BP measurements were 118/77 mmHg (range 95/60-140/102) and 115/70 mmHg (range 93/57-154/99), respectively. There was minimal difference between the two methods with a positive bias of 2.4 mmHg for diastolic BP and a negative bias of 2.1 mmHg for systolic BP. The mean standard deviation scores (SDS) corresponding to the mean BP recordings were 24 h systolic + 0. 81 (range - 1.26 to + 4.45), 24 h diastolic + 0.43 (range - 0.85 to + 3.42), day-time systolic + 1.08 (range - 0.95 to + 4.72), day-time diastolic + 0.70 (range - 0.94 to + 3.71), night-time systolic + 0. 22 (range -2.2 to + 3.64) and night-time diastolic - 0.18 (range -2. 0 to + 2.43). The SDS for both the mean 24 h and day-time systolic and diastolic BP were shifted to the right of the normal distribution. 57% of the girls had less than the normal 10% reduction in nocturnal systolic blood pressure. 17% had diastolic and 21% had systolic blood pressure above the 95th percentile for age and sex. There was no significant difference in the BP SDS between girls on no treatment and those receiving treatment.

CONCLUSION

Over 50% of girls with Turner syndrome have an abnormal BP circadian rhythm, which is similar to adult patients with secondary hypertension. Patients with Turner syndrome have higher blood pressure measurements compared to published population standards, as evidenced by the shift to the right of both the systolic and diastolic BP SDS. These findings suggest that girls with Turner syndrome should be carefully monitored in childhood and adulthood for blood pressure and other cardiovascular risk factors.

The influence of renal and cardiovascular abnormalities on blood pressure in Turner syndrome

INTRODUCTION

Patients with Turner syndrome (TS) are at an increased risk of morbidity and mortality from cardiovascular disease. This study was undertaken to establish the prevalence of hypertension in patients with TS and to establish to what extent cardiovascular or renal abnormalities contribute to the measured blood pressure.

PATIENTS AND METHODS

62 patients with TS, age 5.4-22.4 years, had 24 h-ABPM (ambulatory blood pressure monitoring), echocardiography, renal imaging and measurement of recumbent plasma renin activity (PRA). Blood pressure was compared with population standards.

RESULTS

21% of the TS study population had mean systolic and 17% mean diastolic 24 h-ABPM measurements above the 95th percentile for age and sex (i.e. mild hypertension). Borderline blood pressure (i.e. 90th to 95th percentile) was found in another 17% of the patients. 57% of the patients had a blunted (i.e. less than 10%) fall in the night-time blood pressure. 24% of the patients had a detectable cardiac abnormality, 42% a detectable renal abnormality and 52% were found to have raised plasma renin activity. The presence of a cardiac or renal abnormality had no significant effect on blood pressure. Blood pressure of patients on growth and/or pubertal therapy was not different from those patients on no such treatment.

CONCLUSION

Over 30% of patients with Turner syndrome were found to be mildly hypertensive and over 50% had an abnormal diurnal blood pressure profile. In this study we were unable to demonstrate that the presence of renal or cardiac abnormalities had an effect on recorded blood pressure. The use of growth hormone and oestrogen to manage growth failure and pubertal delay did not seem to affect blood pressure. This study suggests that there is a high prevalence of raised blood pressure in Turner syndrome patients. The 24 h-ambulatory blood pressure monitoring profile suggests that this may be secondary in origin, but we were unable to demonstrate an underlying mechanism with the renal and cardiac investigations performed.

Evidence-based growth hormone therapy prediction models

Prediction models describing the response of various pathophysiological states to intervention can be of value in confirming a diagnosis, determining the prognosis and promoting compliance with treatment. The rigorous evaluation process of evidence-based medicine, used to assess any diagnostic test or therapeutic intervention, should be applied to studies reporting the development, validation and application of these prediction models. The models can provide only an estimate of the average effect to be expected, so the failure of an individual to exhibit an 'average' response does not necessarily imply a problem with that patient. Further development of the models is required to overcome inherent statistical problems and to allow greater applicability to the individual patient.

Mutational analysis of DAX1 in patients with hypogonadotropic hypogonadism or pubertal delay

Although delayed puberty is relatively common and often familial, its molecular and pathophysiologic basis is poorly understood. In contrast, the molecular mechanisms underlying some forms of hypogonadotropic hypogonadism (HH) are clearer, following the description of mutations in the genes KAL, GNRHR, and PROP1. Mutations in another gene, DAX1 (AHC), cause X-linked adrenal hypoplasia congenita and HH. Affected boys usually present with primary adrenal failure in infancy or childhood and HH at the expected time of puberty. DAX1 mutations have also been reported to occur with a wider spectrum of clinical presentations. These cases include female carriers of DAX1 mutations with marked pubertal delay and a male with incomplete HH and mild adrenal insufficiency in adulthood. Given this emerging phenotypic spectrum of clinical presentation in men and women with DAX1 mutations, we hypothesized that DAX1 might be a candidate gene for mutation in patients with idiopathic sporadic or familial HH or constitutional delay of puberty. Direct sequencing of DAX1 was performed in 106 patients, including 85 (80 men and 5 women) with sporadic HH or constitutional delay of puberty and patients from 21 kindreds with familial forms of these disorders. No DAX1 mutations were found in these groups of patients, although silent single nucleotide polymorphisms were identified (T114C, G498A). This study suggests that mutations in DAX1 are unlikely to be a common cause of HH or pubertal delay in the absence of a concomitant history of adrenal insufficiency.

HESX1: a novel gene implicated in a familial form of septo-optic dysplasia

The homeobox gene Hesx1, which encodes a pituitary transcription factor, is first expressed at gastrulation in the mouse embryo. Hesx1 expression begins in prospective forebrain tissue but later becomes restricted to Rathke's pouch, the primordium of the anterior pituitary gland. Transgenic mice lacking Hesx1 exhibit a phenotype comprising variable anterior CNS defects, such as a reduced prosencephalon, abnormalities in the corpus callosum and septum pellucidum, anophthalmia or microphthalmia, defective olfactory development and bifurcations in Rathke's pouch with pituitary dysplasia. A comparable and highly variable phenotype in humans is septo-optic dysplasia. We have cloned and sequenced the human homologue HESX1 and screened for mutations in affected individuals using single-stranded conformational polymorphism analysis. Two siblings with septo-optic dysplasia were homozygous for a missense mutation within the HESX1 homeobox. This mutation resulted in the substitution of a highly conserved arginine residue (Arg53) by cysteine and led to a loss of in vitro DNA binding. Hence, a vital role for Hesx1/HESX1 in forebrain and pituitary development in mice and humans is suggested.

The relative roles of continuous growth hormone-releasing hormone (GHRH(1-29)NH2) and intermittent somatostatin(1-14)(SS) in growth hormone (GH) pulse generation: studies in normal and post cranial irradiated individuals

OBJECTIVES

Pulsatile GH release in humans is thought to involve the coordinated interaction of growth hormone-releasing hormone (GHRH) and somatostatin (SS). Disordered GH secretion is seen in most patients following high dose (> 30 Gy) cranial irradiation in childhood and could result from dysregulation of these hypothalamic hormones or reflect direct pituitary damage. We have used a peptide 'clamp' to assess the relative roles of continuous GHRH and intermittent SS in GH pulse generation in healthy volunteers and short-and long-term survivors of childhood brain tumours.

DESIGN

Randomized controlled study.

PATIENTS

12 adult male long-term survivors of childhood brain tumours (median age 17.0 years (15.2-19. 7); 12.2 years (5.8-14.0) postradiotherapy, > 30Gy whole brain irradiation) with 9 matched control volunteers and 6 short-term survivors of childhood brain tumours (median age 6.4 years (5.9-7. 7); 2.5 years (1.7-3.6) post radiotherapy, > 30Gy whole brain irradiation) with 6 matched controls (studies of spontaneous GH release alone).

MEASUREMENTS

Serum GH concentrations in 24 h spontaneous GH profiles and during three 'clamp' studies: continuous GHRH(1-29)NH2 (60 ng/kg/minutes, subcutaneous infusion, 24 h); intermittent SS(1-14) withdrawal (20microg/m2/hour, intravenous infusion, 3 h on/1 h off, 2-3 cycles over 8-12 h); intermittent SS and continuous GHRH combined (2-3 cycles over 8-12 h). Data were analysed by spectral analysis, 'peak' and 'trough' determination and serial array averaging.

RESULTS

In normal adults, discrete pulsatility was seen in all profiles of spontaneous GH secretion. Continuous GHRH amplified peak GH concentrations (median basal peak 21.1 mU/l vs. GHRH 62.0 mU/l, P = 0.008) whilst pulse timing remained unaffected. Rebound GH release following SS withdrawal alone was variable. Combining continuous GHRH with intermittent SS produced regular GH responses upon SS withdrawal (20.3 mU/l; range 2. 3-105.4). Heterogeneous patterns of spontaneous GH release were seen in the irradiated subjects. Spontaneous peak GH release was reduced in the children following irradiation (Irradiation 14.9 mU/l vs. Control 25.1 mU/l, P = 0.007). Peak GH concentrations were significantly amplified by GHRH in half of them. Adult long-term survivors had lower spontaneous GH concentrations and continuous GHRH amplified GH release in most subjects (Spontaneous 4.2 mU/l vs. GHRH 6.5 mU/l, P = 0.008) but peak concentrations remained far less than those of controls. Combining intermittent SS with continuous GHRH regularized GH release in many patients but the GH responses remained attenuated (4.6 mU/l; 2.5-17.5).

CONCLUSION

GH pulsatility can be generated in normal volunteers by the combination of continuous GHRH and intermittent SS and provides indirect evidence for a role for GHRH in GH synthesis and replenishment of stored GH pools at times of high SS tone. Patterns of GH release in short-and long-term survivors of childhood brain tumours are heterogeneous suggesting that combined hypothalamic deficiencies of GHRH and SS occur following high dose radiotherapy. The attenuated GH release seen in long-term survivors compared to controls suggests that GH secretory dysfunction does not simply reflect reduced GHRH and SS secretion, and that trophic effects or pituitary damage may be important with time.