Functional characterisation of the H365Y mutation of the 21-hydroxylase gene in congenital adrenal hyperplasia

The study subject was a 13 day-old boy admitted to hospital, with weight loss since birth. He presented with the vomiting and hypotension that are classical features of congenital adrenal hyperplasia (CAH). The most common type of CAH is an autosomal recessive disorder caused by mutations in the 21-hydroxylase (CYP21A2) gene. To examine the CYP21A2 gene, gene-specific PCR was carried out, followed by sequencing. The baby was shown to be a compound heterozygote H365Y/R356W for two CYP21A2 gene mutations each inherited from a different parent. One of the mutations has not previously been functionally characterised. The mutations were reconstructed in an expression plasmid and characterised in vitro after transient transfection into human embryonic kidney (HEK293T) and hepatoblastoma (C3A) cell lines followed by measurement of enzyme activity. The CYP21A2 H365Y mutant exhibited minimal 21-hydroxylase activity to convert 17-hydroxyprogesterone to 11-deoxycortisol or progesterone to 11-deoxycorticosterone. Western immunoblotting indicated that the H365Y enzyme was produced in more variable amounts than wild type; in particular, the H365Y mutant protein may be unstable and/or subject to a more rapid degradation by the human proteosome as well as catalytically inefficient. The double mutant genotype with a severe mutation on each allele is compatible with the clinical presentation.

Abstract P3-12-06: Biomarkers of Malignant Potential in Breast Tissue in Relation to Short-Term Breast Cancer Risk

Background:

Biomarkers expressed in benign or normal breast tissue may be important indicators of subsequent risk of malignancy, but investigations identifying such have been few. Limited previous evidence suggests that loss of expression of several breast cancer tumor markers in benign tissue, relative to normal tissue, may contribute to malignant progression. We examined expression of markers implicated in tumorigenesis among women who developed breast cancer shortly after benign biopsy. Material and Methods:

We conducted a nested case-control study within a population-based cohort of 15,000 women who received benign breast biopsies between 1996 and 2005 in six New Mexico counties. We identified 95 women who developed breast cancer within 5 years of biopsy, and matched them to 3 similar controls who did not develop cancer. Benign breast as well as adjacent normal tissue was assayed using immunohistochemistry for epithelial and stromal markers plausibly related to risk of cancer development. Logistic regression models were employed to estimate odds ratios and 95% confidence intervals for breast cancer risk after adjustment for age, race/ethnicity, and risk category of benign biopsy. Results:

Women who expressed estrogen receptor alpha in their normal tissue (10% or greater staining) had a 2.9-fold increased breast cancer risk (95% confidence interval (CI) 1.0-8.3). Those who expressed Cytokeratin 5/6 (Odds ratio (OR) 3.3; 95% CI 1.2-8.8) or Her2/neu (30% or greater staining) (OR 8.2; 95% CI 0.9-70.6) in normal tissue also appeared to have an elevated breast cancer risk, relative to those with expression below the threshold. In contrast, the presence of these markers in benign tissue was unrelated to subsequent development of breast cancer. Estrogen receptor staining of 10% or greater in normal tissue, but absence of staining in benign tissue, was not a risk factor for progression to breast malignancy (OR 4.9; 95% CI 0.7-34.8) Discussion:

Our results suggest that biomarker expression in normal breast tissue may be an important component of risk assessment among women whoreceive benign breast biopsies. Findings such as these aim to identify women at highest risk for breast cancer development, allowing for the implementation of more frequent follow-up and new targeted interventions, while classifying most women as at low risk, providing reassurance and reducing the need for chemoprevention.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-12-06.

Abstract P2-06-16: Total Choline Measurement in Human Breast Using High-Speed MR Spectroscopic Imaging at 3T

PURPOSE: We developed a novel, quantitative and high-speed MR spectroscopic imaging (MRSI) method to map total Choline (tCho), a sensitive biomarker of breast tumor status, as an adjunct to enhance the limited specificity of routine dynamic-contrast enhanced (DCE) MRI. Quantitative tCho maps measured in 7 minutes were compared with tCho obtained with conventional Single Voxel Spectroscopy (SVS). METHOD AND MATERIALS: Measurements on a total of 18 healthy female subjects (mean age: 25.6±5) were performed using 3T MR scanners (Siemens Trio, Erlangen, Germany) located at the two partner sites equipped with 4-channel breast coil (Siemens, Erlangen, Germany) or 8-channel breast coil (Sentinelle Medical, Toronto, Canada). 2D MRSI data of an entire oblique slice were collected using Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI) [1] with MEGA lipid suppression. Acquisition parameters were: TR/TE=1500ms/125ms, matrix size=32x32, voxel size=2x2x2mm3 (8cc), number of signal averages= 16 with weighted k-space sampling and total acquisition time=7 minutes. PRESS SVS data were acquired with 8 cc voxel size using identical TR/TE and acquisition time. The absolute metabolite concentration was calculated in reference to tissue water (millimoles of tCho per kilogram of solute) using LCModel (s-provencher.com) fitting to estimate the Choline peak baseline and subsequent spectral integration using a Cramer-Rao lower bound threshold of 25%.

RESULTS: tCho was detected in 7 of the 15 subjects (47%) in both SVS and PEPSI data. In the PEPSI data sets, tCho was detected in multiple voxels (Fig. 1). Subjects in which tCho was detected exhibited narrower water line width and smaller lipid content than subjects in which tCho was not detectable (2-tailed t-test, P<0.01). The absolute tCho concentrations corrected for relaxation effects in these 7 subjects using SVS and PEPSI was 0.43±0.34 mmol/kg and 0.51±0.19 mmol/kg, respectively. In comparison with SVS data (21.8±8.6Hz), PEPSI spectra demonstrated larger water line width (33.9±12.6Hz) and displayed greater lipid contamination from adipose tissue areas and larger baseline distortion due to the spatial point spread function.

CONCLUSION: Despite less favorable shimming and lipid suppression conditions compared to SVS, it is feasible to quantitatively map tCho in healthy breast tissue using high-speed MRSI, with concentration values that are consistent with those from SVS. Studies in breast cancer patients are in progress to assess the feasibility of breast cancer diagnosis and treatment monitoring with MRSI. Results will be reported at the Symposium. The long-term goals are to utilize high-speed MRSI as an early predictor of treatment failure in women undergoing systemic therapy (i.e. chemotherapy, endocrine therapy) for breast cancer and to develop an improved screening protocol for high risk patients. Fig. 1: PEPSI slice localization (left) and spectral array (right) with superimposed LCModel fit and integrated tCho peak

Ref: (1) Posse et al. Magn. Reson. Med. 2007;58(2):236-244.

Comparison of the prognostic value of tumour- and patient-related factors in patients undergoing potentially curative surgery for colon cancer

AIM

To comprehensively compare the prognostic value of tumour- and patient-related factors in patients undergoing curative surgery for colon cancer.

METHOD

From a database of 287 patients who underwent elective resection between 1997 and 2005, tumour factors including stage and host factors including systemic inflammatory response [modified Glasgow Prognostic Score (mGPS)] were identified.

RESULTS

Median follow-up was 65 months. Over this period, 125 patients died, 80 from cancer. On multivariate analysis of all significant patient and tumour related factors, Dukes stage (P < 0.01), vascular invasion (P < 0.01) and the mGPS (P < 0.01) were independently associated with cancer-survival. Of the patient-related factors, age (P < 0.01), haemoglobin (P < 0.01), white-cell (P < 0.01), neutrophil (P < 0.01) and platelet (P < 0.01) counts, and alkaline phosphatase (P < 0.01) were most significantly associated with the mGPS.

CONCLUSION

In addition to tumour-related factors such as Dukes stage and vascular invasion, the preoperative mGPS should be included to guide prognosis in patients undergoing curative resection for colon cancer.

Nomogram for the decline in serum antimüllerian hormone: a population study of 9,601 infertility patients

OBJECTIVE

To define an optimal model for the decline in circulating antimüllerian hormone (AMH) with age and develop a validated age-related nomogram.

DESIGN

Cohort study with validation of linear, biphasic linear, differential, power, and quadratic equations undertaken in two additional cohorts.

SETTING

United Kingdom infertility clinics.

PATIENT(S)

Training cohort of 4,590 infertile women. Two separate validation cohorts; 4,588 infertile women, and 423 women with confirmed ovulation and normal pelvic ultrasound who have a male partner with severe oligospermia.

INTERVENTION(S)

Serum AMH measurement.

MAIN OUTCOME MEASURE(S)

Optimal fit and age-related AMH nomogram.

RESULT(S)

The linear model had the largest sum of absolute and squared residuals and provided a less adequate fit than the four nonlinear models. Of these, the R(2) ranged from 19.45% to 19.48% in the training dataset, from 21.30% to 21.36% in the validation dataset, and from 13.29% to 13.75% in the partners of oligospermic males. The parameters of the differential model were difficult to estimate, and the goodness-of-fit of the power model was slightly inferior to the quadratic model.

CONCLUSION(S)

Circulating AMH concentrations decline with increasing reproductive age in a manner optimally described by a quadratic equation. This validated age-related AMH nomogram will enable counseling of infertility patients regarding reproductive performance.

Measurement of 25-hydroxyvitamin D in the clinical laboratory: current procedures, performance characteristics and limitations

In this review we describe procedures, performance characteristics and limitations of methods available for the measurement of 25-hydroxyvitamin (25OHD) since the year 2000. The two main types of methods are competitive immunoassay and those based on chromatographic separation followed by non-immunological direct detection (HPLC, LC-MS/MS). Lack of a reference standard for 25OHD has, until recently, been a major issue resulting in poor between-method comparability. Fortunately this should soon improve due to the recent introduction of a standard reference material in human serum (SRM 972) from the National Institute of Standards and Technology (NIST). For immunoassay, specificity can be an issue especially in relation to the proportion of 25OHD2 that is quantified whereas HPLC and LC-MS/MS methods are able to measure the two major vitamin D metabolites 25OHD2 and 25OHD3 independently. HPLC and LC-MS/MS require more expensive equipment and expert staff but this can be offset against lower reagent costs. Increasingly procedures are being developed to semi-automate or automate HPLC and LC-MS/MS but run times remain considerably longer than for immunoassays especially if performed on automated platforms. For most HPLC and LC-MS/MS methods extraction and procedural losses are corrected for by the inclusion of an internal standard which, in part, may account for higher results compared to immunoassay. In general precision of immunoassay, HPLC and LC-MS/MS are comparable and all have the required sensitivity to identify severe vitamin D deficiency. Looking to the future it is hoped that the imminent introduction of a standard reference method (or methods) for 25OHD will further accelerate improvements in between method comparability.

The concordance between serum anti-Mullerian hormone and testosterone concentrations depends on duration of hCG stimulation in boys undergoing investigation of gonadal function

BACKGROUND

In boys undergoing investigation of gonadal function, the relationship between a single measurement of serum anti-Mullerian hormone (AMH) and hCG stimulated serum testosterone is unclear.

AIM

The aim of the study was to assess concordance between serum AMH and testosterone concentrations following hCG stimulation of two different durations.

METHODS

Samples from 284 children (M : F, 154 : 130) with a median age of 8 years (10th, 90th centiles, 0.25, 14) were used to establish an AMH reference range. Clinical data were reviewed in boys undergoing investigation of gonadal function and who had an AMH measurement and a hCG stimulated (3-day or 3-week) (n = 26) testosterone. Of these 26 boys, 11 had combined genital anomalies, whereas the rest had conditions such as isolated hypospadias, undescended testes or microphallus. Normal testosterone response to hCG stimulation was defined as a level greater than 3.5 nmol at day 4 and 9.5 nmol/l at day 22.

RESULTS

In the reference group, the 5th centile AMH for boys below 1 year was 215 pmol/l and between 1 and 8 years 180 pmol/l. The 95th centile for girls for these respective age groups was 30 pmol/l and 25 pmol/l. In those cases where serum testosterone concentrations were available at day 1, day 4 and day 22 of the 3 week-hCG test, five cases had a normal serum testosterone at day 4 and three cases only showed such a response by day 22. In those where serum AMH was less than 180 pmol/l, a poor testosterone response of less than 3.5 nmol was observed in approximately seven of eight (88%) cases with a 3-day hCG stimulation test or the 3-week test. An AMH of greater than 180 pmol/l was associated with a normal testosterone response at day 4 in 10 out of 15 (67%) cases and at day 22 in eight of 11 (73%) cases. However, a low serum testosterone concentration of less than 3.5 nmol after the 3-day hCG test was only associated with a likelihood of a low AMH in three of eight (37%) cases. With the 3-week hCG test, a low day 22 testosterone of 9.5 mmol/l or less was associated with a low AMH of 180 pmol/l or less in four of seven (57%) cases.

CONCLUSION

In boys undergoing investigation of gonadal function, the concordance between AMH and testosterone is better at day 22 than day 4. A normal AMH may provide useful information on overall testicular function but does not exclude the need for an hCG stimulation test.

A screening procedure for primary aldosteronism based on the Diasorin Liaison® automated chemiluminescent immunoassay for direct renin

Background

Primary aldosteronism (PA), the most common secondary cause of hypertension, can be screened for using the aldosterone/renin ratio. This ratio is raised in PA and its accuracy depends on the ability to measure plasma renin at extremely low concentrations.

Methods

We compared two different procedures for assessing plasma renin. The conventional method, which measures plasma renin activity (PRA), is technically demanding and laborious, and the Diasorin Liaison® method, which measures plasma renin concentration (PRC), is an automated immunoassay. Results from each method were used to calculate the aldosterone/renin ratio (ARR) and the performance of the Diasorin Liaison® method compared with that of the conventional assay using receiver operator characteristic curves.

Results

The analytical and functional sensitivity of the PRC method were 2.1 and 5 μIU/mL, respectively. Intra- and inter-assay precision were <7.2% and 10.4%, respectively. There was significant (9%) prorenin interference. Samples with PRA > 1.0 ng/mL/h showed significant correlation with PRC ( r = 0.93; P < 0.05; n = 146); however, with PRA < 1.0 ng/mL/h, no significant correlation occurred ( r = 0.14; P < 0.05; n = 79). An aldosterone (pmol/L)/PRC(μIU/mL) ratio of >35, in patients with aldosterone >300 pmol/L, resulted in 100% sensitivity and 93% specificity, when compared with the commonly accepted aldosterone (pmol/L)/PRA (ng/mL/h) ratio of >750, in identifying patients who may suffer from PA.

Conclusion

This study indicates the feasibility of using the automated PRC assay as a replacement for the conventional manual PRA assay in calculating the ARR as a first-line screen for PA.

Exaggerated adrenarche in a cohort of Scottish children: clinical features and biochemistry

OBJECTIVE

To investigate the reported association between exaggerated adrenarche (EA) and reduced foetal growth and to identify possible risk factors for future morbidity in Scottish children with clinical features of EA.

DESIGN

Three-year prospective study.

MEASUREMENTS

Auxology, blood pressure (BP), biochemical analysis of blood and urine, pelvic ultrasound in girls.

RESULTS

Fifty-two patients were recruited of whom one girl had nonclassical congenital adrenal hyperplasia (17-OHP 17 nmol/l) and one had insufficient blood for analysis. The final cohort comprised 42 girls of mean (SD) age 7.7 (0.99) and eight boys of 8.8 (0.67) years. Mean (SD) birth weight was 3.27 (0.49) and 3.10 (0.76) kg in girls and boys respectively. Height/weight SDS were 1.13/1.69 in girls and 1.69/1.88 in boys. Mean systolic/diastolic BP was 107.8/60.4 (50th-75th centile) in girls and 115.5/63.9 (75th-91st centile) in boys. Uterine and ovarian development was prepubertal. Median serum dehydroepiandrosterone sulphate (DHEAS) was 2.1 and 4.1 mumol/l, androstenedione 3.1 and 3.8 nmol/l in girls and boys respectively, with DHEAS within the reference range/undetectable in 18/2 and androstenedione in 12/6 patients. Fasting insulin was 9.0 and 15.0 mU/l in girls and boys respectively, with concomitant low normal SHBG. Anti-Mullerian hormone (AMH) was 15.7 pmol/l in 27 girls, compared with 5.0 pmol/l in normal girls aged 5-8 years.

CONCLUSIONS

Our Scottish EA cohort showed female predominance, no evidence of reduced foetal growth, a tendency to overweight with commensurate mild hyperinsulinaemia and modest elevation of serum androgens in some patients. We have found raised AMH levels in the girls, indicating advanced ovarian follicular development.

Familial and phenotypic associations of the aldosterone Renin ratio

CONTEXT

The aldosterone to renin ratio (ARR) is a marker of aldosterone excess, widely used to screen for primary aldosteronism (PA). The significance of a raised ARR in normotensive and hypertensive subjects and the phenotypic and familial factors affecting it are unclear.

OBJECTIVE

We estimated the distribution and heritability of the ARR and tested for associations between ARR and blood pressure (BP) with 11 polymorphisms at the CYP11B1/CYP11B2 locus.

DESIGN AND SETTING

A total of 1172 individuals from 248 Caucasian families ascertained via a hypertensive proband were evaluated.

MAIN OUTCOME MEASURE

Plasma aldosterone was measured by RIA, and plasma renin concentration was measured by the LIAISON Direct Renin chemiluminescent immunoassay.

RESULTS

Unadjusted and adjusted ARR were continuously distributed in normotensives and hypertensives, with no evidence of a cutoff that would identify a separate population with PA. Median ARR was 4.19 ng/liter per mIU/liter (range, 0.04-253.16). ARR levels were higher in females and associated with age, body mass index, and potassium. Antihypertensive agents had significant predictable effects on the ARR. Renin was negatively associated, and ARR was positively associated with ambulatory BP readings (P < 0.001) in subjects not taking antihypertensives. The heritability of the ARR was 38.1% (P < 10(-8)). Plasma aldosterone, but not ARR, was influenced by the intron 2 conversion variation in the CYP11B2 gene (beta = -0.07; P = 0.04).

CONCLUSIONS

The ARR is continuously distributed, is influenced by genetic and environmental factors, and is not a marker of a distinct pathological abnormality but possibly reflects the long-term influence of aldosterone on cardiovascular homeostasis.

A re-investigation of saliva collection procedures that highlights the risk of potential positive interference in cortisol immunoassay

BACKGROUND

The use of saliva for measurement of cortisol permits non-invasive study of adrenal function, but collection can be technically difficult, particularly in small infants. Saliva collection can be assisted by citric acid to increase saliva flow, or by the use of cotton or polyester swabs in the mouth.

AIM

To determine whether different methods of saliva collection affect cortisol radioimmunoassay (RIA) performance.

EXPERIMENTAL

Cortisol was measured in saliva collected from 16 adults using intra-oral cotton swabs or polyester swabs, compared with saliva dribbled directly into a pot either alone (plain saliva) or after citric acid had been placed on the tongue. An in-house RIA, without prior extraction, was used to measure cortisol with an encapsulated sheep antibody.

RESULTS

Mean (median) salivary cortisol was 10.9 (10.5) nmol L(-1) in plain saliva, 10.4 (8.4) nmol L(-1) in citric acid stimulated saliva; 25.3 (25.1) nmol L(-1) in saliva collected on cotton swabs, and 27.9 (27.3) nmol L(-1) collected on polyester swabs. Cortisol in saliva collected using citric acid was not significantly different from plain saliva (p=0.997), but cortisol in saliva collected using cotton and polyester swabs was significantly higher than that of plain saliva (p<0.01).

CONCLUSION

The use of cotton or polyester swabs for collection of saliva can result in spuriously high levels of cortisol when measured by RIA.

Short‐term growth and bone turnover in children undergoing occlusive steroid (‘Wet‐Wrap’) dressings for treatment of atopic eczema

To assess the effects of steroid wet-wrap therapy on short-term growth and bone turnover, eight prepubertal (M:F,5:3) children with a median age of 5.1years (range 3.3-8.8) were studied over a 2-week period prior to therapy and at 2-week intervals during therapy. Short-term growth was assessed by measuring lower leg length velocity (LLLV) by knemometry and bone and collagen turnover was assessed by urinary deoxypyridinoline crosslink excretion corrected for creatinine excretion (DPD). Median duration of study during occlusive dressings was 12 weeks (range 2-18). Topical beclomethasone dipropionate diluted 1:10 or 1:4 in white soft paraffin was applied under tubular (Tubifast) bandages in 7/8 children. Median LLLV before and during therapy were 0.43 mm/week (10(th),90(th) centile; 0.0,0.7) and 0.42 mm/week (10(th),90(th) centile; -0.35,1.01), respectively (not significant). Median DPD before and during therapy were 25.9 nmol/l/creatinine (10(th),90(th) centile; 20.8, 33.0) and 26.3 nmol/l/creatinine (10(th),90(th) centile; 21.7, 34.1) respectively (not significant). Non-invasive assessment of the effects of steroid wet-wrap therapy can be performed in children with eczema. These preliminary results show no substantial growth promoting or adverse effects of therapy.

A simple automated solid-phase extraction procedure for measurement of 25-hydroxyvitamin D3 and D2 by liquid chromatography-tandem mass spectrometry

Background

Measurement of 25-hydroxyvitamin D3 (25OHD3) and D2 (25OHD2) is challenging. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods have been described but they are often complex and difficult to automate. We have developed a simplified procedure involving an automated solid-phase extraction (SPE).

Methods

Internal standard (hexadeuterated 25-hydroxyvitamin D3) was added to serum or plasma followed by protein precipitation with methanol. Following centrifugation, a robotic instrument (CTC PAL [Presearch] for ITSP™ SPE [MicroLiter Analytical Supplies, Inc]) performed a six-step SPE procedure and the purified samples were injected into the LC-MS/MS. Quantification of 25OHD3 and 25OHD2 was by electrospray ionization MS/MS in the multiple-reaction monitoring mode.

Results

The lower limit of quantitation was 4.0 nmol/L for 25OHD3 and 7.5 nmol/L for 25OHD2. Within- and between-assay precision was below 10% over the concentration range of 22.5–120 nmol/L for D3 and 17.5–70 nmol/L for D2 ( n = 10). The calibration was linear up to 2500 nmol/L ( r = 0.99). Recoveries ranged between 89% and 104% for both metabolites and no ion suppression was observed. The results obtained compared well ( r = 0.96) with the IDS-OCTEIA 25-hydroxyvitamin D enzyme immunoassay for samples containing less than 125 nmol/L, at higher concentrations the immunodiagnostic system (IDS) method showed positive bias.

Conclusions

Our simplified sample preparation and automated SPE method is suitable for the measurement of 25OHD3 and D2 in a routine laboratory environment. The system can process up to 300 samples per day with no cumbersome solvent evaporation step and minimal operator intervention.

A novel CYP11B2 gene mutation in an Asian family with aldosterone synthase deficiency

CONTEXT

Three siblings of Pakistani origin presented neonatally with isolated hyperreninemic hypoaldosteronism and were well controlled on fludrocortisone therapy during childhood and adolescence.

OBJECTIVE/DESIGN

These individuals were reevaluated as adults after fludrocortisone withdrawal to investigate the biochemical and molecular basis of their disorder.

RESULTS

When reassessed off fludrocortisone treatment, hyperreninemic hypoaldosteronism was confirmed in all subjects but with significant hyperkalemia in only one case. Profiling of urinary steroid metabolites showed a biochemical pattern (elevated tetrahydrocorticosterone to 18-hydroxytetrahydro-11-dehydrocorticosterone ratio but normal 18-hydroxytetrahydro-11-dehydrocorticosterone to tetrahydroaldosterone ratio) consistent with partial type 1 aldosterone synthase deficiency. Sequencing of the CYP11B2 gene showed that affected subjects were homozygous for a single nucleotide substitution (T925C) in exon 5, corresponding to a serine to proline mutation (S308P) in the predicted protein, with unaffected family members being heterozygous. Consistent with structural modeling showing that the mutated residue is located within the alpha-helix I, close to the hemebinding, active site of the enzyme, functional characterization of the S308P mutant protein in vitro showed complete loss of enzyme activity. However, administration of dexamethasone further reduced levels of circulating aldosterone and its urinary metabolites in affected subjects, suggesting that some mineralocorticoid biosynthesis occurs in vivo.

CONCLUSION

We have identified the first CYP11B2 gene defect in a family of Asian origin, associated with a type 1 aldosterone synthase deficiency phenotype. Preservation of some aldosterone production suggests either residual mutant CYP11B2 enzyme activity in vivo or mineralocorticoid biosynthesis via an alternative pathway.

Leptin and coronary heart disease: prospective study and systematic review

OBJECTIVES

This study sought to better determine the link between leptin and coronary heart disease (CHD).

BACKGROUND

Circulating leptin is considered a risk factor for CHD but larger studies are needed.

METHODS

Leptin levels were measured in 550 men with fatal CHD or nonfatal myocardial infarction and in 1,184 controls nested within a prospective study of 5,661 British men and set in context with a meta-analysis.

RESULTS

Baseline leptin correlated with body mass index (BMI), blood pressure, total cholesterol, triglyceride, and inflammatory markers; correlations persisted after BMI adjustment. The within-person consistency of leptin values over 4 years (correlation coefficient: 0.79; 95% confidence interval [CI]: 0.73 to 0.83) was higher than those of some established cardiovascular risk factors. In a comparison of individuals in the top third with those in the bottom third of baseline leptin, the age- and town-adjusted odds ratio for CHD was 1.25 (95% CI: 0.96 to 1.62), decreasing to 0.98 (95% CI: 0.72 to 1.34) after adjustment for BMI. A systematic review identified 7 prospective reports with heterogeneous findings (I(2) = 60%, 13% to 82%). The combined adjusted risk ratio across all studies was 1.44 (95% CI: 0.95 to 2.16) in a comparison of extreme thirds of leptin levels. The inconsistency between studies was partially explained by sample size, with combined estimates from studies involving >100 CHD cases (1.28, 95% CI: 0.80 to 2.04) being somewhat weaker than those from smaller studies (1.81, 95% CI: 0.76 to 4.31).

CONCLUSIONS

Previous studies appear to have overestimated associations of leptin and CHD risk. Our results suggest a moderate association that is largely dependent on BMI.

A 5-year-old boy with cryptorchidism and pubic hair: investigation and management of apparent male disorders of sex development in mid-childhood

BACKGROUND

Late presentation of congenital adrenal hyperplasia as a 46,XX disorder of sex development due to 11-beta hydroxylase deficiency is uncommon. Such a case raises issues regarding appropriate investigation and management.

CASE HISTORY

A 5-year-old boy who had recently moved to the United Kingdom presented at the endocrinology clinic with recurrent abdominal pain. He was normotensive and had a history of ambiguous genitalia since birth, a relatively small penis, bilateral cryptorchidism and pubic hair. A systematic workup revealed low anti-Mullerian hormone levels for age and sex and elevated serum testosterone, androstenedione and deoxycortisol levels. A urinary steroid profile confirmed a diagnosis of 11-beta hydroxylase deficiency. The child's karyotype was 46,XX. Further genetic analysis revealed a compound heterozygote mutation in the CYP11B1 gene. Ultrasound scan showed evidence of Mullerian structures and accumulation of menstrual blood in the vagina (haematocolpos). Following discussion at a multidisciplinary clinic, the patient did not undergo sex reassignment and subsequently proceeded to surgery for removal of the Mullerian structures.

CONCLUSIONS

This case emphasizes the importance of a systematic approach to investigation of older children presenting with apparent male undermasculinisation. It also raises important issues about gender reassignment in mid-childhood and the indications for removal of Mullerian organs in a 46,XX boy.

Feline combined diaphyseal radial and ulnar fractures. A retrospective study of 28 cases

Feline combined diaphyseal radial and ulnar fractures were reviewed in a retrospective study of cases that were admitted to two university teaching hospitals. A high incidence of complications was noted, with 6/26 (23.1%) of cases requiring revision surgery. Open fractures were significantly more likely to require revision surgery. The two main repair methods were external skeletal fixation (ESF) or radial plating. The success rate was greater for radial plating, with only 1/10 (10%) cases requiring revision versus 4/14 (28.6%) for ESF. However, ESF tended to be applied to the more complicated fractures. Stabilisation of both bones proved to be an effective repair strategy with only 1/8 cases (12.5%) requiring revision versus 5/18 cases (27.8%) where only one bone was stabilised. Synostoses and radiohumeral luxation were noted as complications associated with the fractures stabilised by ESF. Final limb function following recovery was assessed as 'good' or 'excellent' in 93.3% of cases.

Effect of moderate-intensity exercise session on preprandial and postprandial responses of circulating ghrelin and appetite

Responses of plasma total ghrelin and appetite were investigated during preprandial and postprandial stages of recovery from a moderate-intensity cycling session. Healthy recreationally active men underwent one exercise and one control trial. In the exercise trial, subjects exercised for approximately 60 minutes, while in the control trial they rested quietly for the same duration. After the intervention, subjects rested for 120 minutes and then consumed a test meal. Measurements were obtained immediately and 120 minutes after the intervention and then during 180 minutes of the postprandial period. The post-intervention concentration of total ghrelin was lower (p<0.05) in the exercise than in the control trial. The modulating effect of exercise was related to the reduction in the postprandial rather than preprandial concentration. Post-intervention scores of appetite were not different between the two trials, but when preprandial and postprandial responses were considered separately, postprandial hunger and desire to eat was higher (p<0.05) in the exercise trial. In summary, during recovery from moderate-intensity exercise, total ghrelin does not respond in a compensatory manner to disturbances in energy balance. Thus, an exercise-induced increase in appetite during the later stages of recovery coinciding with the postprandial state cannot be explained by changes in the plasma concentration of total ghrelin.

Effect of variation in CYP11B1 and CYP11B2 on corticosteroid phenotype and hypothalamic-pituitary-adrenal axis activity in hypertensive and normotensive subjects

BACKGROUND

Aldosterone is important in the development of hypertension. We have shown that a single nucleotide polymorphism (SNP) (-344T) in the 5' regulatory region (UTR) of the gene encoding aldosterone synthase (CYP11B2) associates with aldosterone excess and hypertension as well as altered adrenal 11-hydroxylation efficiency (deoxycortisol to cortisol). This conversion is carried out by the enzyme 11beta-hydroxylase, encoded by the adjacent gene, CYP11B1. We proposed that the effects of CYP11B2 are explained by linkage disequilibrium (LD) across the CYP11B locus. We have demonstrated high LD across this locus and identified two SNPs in the 5' UTR of CYP11B1 (-1859 G/T, -1889 A/G) that associate with reduced transcription in vitro and altered 11-hydroxylation efficiency in vivo. Accordingly, we hypothesized that the reduced adrenal 11-hydroxylation may lead to chronic resetting of the pituitary-adrenal axis, with chronically increased ACTH drive resulting in aldosterone excess.

METHODS

To test this, we examined hypothalamic-pituitary-adrenal (HPA) axis activity in hypertensive and normotensive individuals stratified according to genotype at CYP11B2 (-344T/C) and CYP11B1 (-1859 G/T, -1889 A/G). Fifty-six subjects homozygous for CYP11B2 SNP (27 TT, 12 CC), and 38 homozygous for CYP11B1 SNPs (18 TTGG, 20 GGAA) were recruited. Diurnal variation and the effects of dexamethasone suppression and ACTH stimulation on plasma aldosterone, cortisol and ACTH under controlled conditions were studied.

RESULTS

Subjects with SNPs associated with reduced 11-hydroxylation efficiency (-344T CYP11B2; TTGG CYP11B1) showed reduced inhibition of ACTH after dexamethasone (P = 0.05) and an altered cortisol-ACTH relationship (decreased cortisol-ACTH ratio, P < 0.02). The same individuals also demonstrated close correlations between plasma cortisol and aldosterone (-344T CYP11B2 r = 0.508, P < 0.004; TTGG CYP11B1 r = 0.563, P < 0.003) suggesting that there was common regulation (possibly ACTH) of these hormones in genetically susceptible subjects.

CONCLUSIONS

Variation in CYP11B2 and CYP11B1 associates with chronic up-regulation of the HPA axis. These novel data support the suggestion that chronic aldosterone excess, in genetically susceptible individuals, may be a consequence of increased ACTH drive to the adrenal and identify novel molecular mechanisms that may lead to the development of hypertension within the general population.

Prolonged human chorionic gonadotrophin stimulation as a tool for investigating and managing undescended testes

OBJECTIVE

To observe the outcome in a group of children with undescended testes (UDT) given prolonged human chorionic gonadotrophin (hCG) stimulation as part of their management.

STUDY DESIGN

Retrospective review of 16 prepubertal boys given intramuscular hCG, 1500 U, on Days 1, 2 and 3 and then twice a week for 2 weeks with assessment of serum testosterone (T), SHBG, dihydrotestosterone (DHT) and androstenedione (A) on Days 1, 4 and 22.

RESULTS

In seven boys (44%), peak rise in T was by Day 4; in 5 boys (31%), the rise was by Day 22 and in the remainder, serum T stayed low. The median Day1 testosterone : androstenedione (T : A) ratio rose from 0.4 (range 0.2-1.5) to 1.7 (range 0.2-5.3) at Day 4 (P < 0.05) with no further rise by Day 22. The median dihydrotestosterone : testosterone ratio (DHT : T) at Day 1 and Day 4 remained unchanged. SHBG levels were more likely to be lower at Day 22 than at Day 4. The mean testosterone : SHBG (T : SHBG) ratio as a marker of androgen sensitivity was 0.2 (1SD 0.1). Bilateral testicular descent deemed immediate surgery unnecessary in 3 out of 15 (20%) boys where outcome data were available.

CONCLUSION

Whilst a 3-day hCG stimulation regimen may exclude 17beta-hydroxysteroid dehydrogenase-3 and 5alpha-reductase deficiencies, some boys with cryptorchidism may require more prolonged stimulation to assess androgen production and sensitivity. The possibility that this regimen leads to a reduced need for orchidopexy requires further exploration.