Novel H6PDH mutations in two girls with premature adrenarche: 'apparent' and 'true' CRD can be differentiated by urinary steroid profiling.

Inactivating mutations in the enzyme hexose-6-phosphate dehydrogenase (H6PDH, encoded by H6PD) cause apparent cortisone reductase deficiency (ACRD). H6PDH generates cofactor NADPH for 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1, encoded by HSD11B1) oxo-reductase activity, converting cortisone to cortisol. Inactivating mutations in HSD11B1 cause true cortisone reductase deficiency (CRD). Both ACRD and CRD present with hypothalamic-pituitary-adrenal (HPA) axis activation and adrenal hyperandrogenism. To describe the clinical, biochemical and molecular characteristics of two additional female children with ACRD and to illustrate the diagnostic value of urinary steroid profiling in identifying and differentiating a total of six ACRD and four CRD cases. Clinical, biochemical and genetic assessment of two female patients presenting during childhood. In addition, results of urinary steroid profiling in a total of ten ACRD/CRD patients were compared to identify distinguishing characteristics. Case 1 was compound heterozygous for R109AfsX3 and a novel P146L missense mutation in H6PD. Case 2 was compound heterozygous for novel nonsense mutations Q325X and Y446X in H6PD. Mutant expression studies confirmed loss of H6PDH activity in both cases. Urinary steroid metabolite profiling by gas chromatography/mass spectrometry suggested ACRD in both cases. In addition, we were able to establish a steroid metabolite signature differentiating ACRD and CRD, providing a basis for genetic diagnosis and future individualised management. Steroid profile analysis of a 24-h urine collection provides a diagnostic method for discriminating between ACRD and CRD. This will provide a useful tool in stratifying unresolved adrenal hyperandrogenism in children with premature adrenarche and adult females with polycystic ovary syndrome (PCOS)

Plasma 1,5-anhydro-d-glucitol concentration and its relation to other plasma components in renal failure and renal transplant recipients

Plasma levels of 1,5-anhydro-D-glucitol (AG) were measured in non-diabetic patients with renal failure or following renal transplant. For patients with renal failure (n = 20) from various causes, the plasma level of AG was found to be positively associated with urate and negatively with both urea and prior dialysis. The results for seven renal transplant recipients, serially assessed during the post-transplant period, verified an increase in plasma AG with time, approaching normal levels (> or = 70 mumol/l) after 60 days, and which was adversely affected by rejection episodes. The actual mean rate of plasma AG rise ranged from 0.35 to 1.29 mumol/l per day. AG levels for long term (> 1000 days) surviving renal transplant recipients (n = 16) were predominantly related to renal function as assessed by plasma creatinine

Nitroglycerin tolerance in human vessels: evidence for Impaired Nitroglycerin Bioconversion

Background—The basis for progressive attenuation of the effects of organic nitrates during long-term therapy (nitrate tolerance) remains controversial; proposed mechanisms include impaired nitrate bioconversion resulting in decreased release of nitric oxide (NO) from nitrates and/or increased NO clearance through a reaction with incrementally generated superoxide (O2–). Methods and Results—Patients undergoing elective coronary artery bypass were randomized to receive 24 hours of intravenously infused nitroglycerin (NTG; nitrate group) or no nitrate therapy (control group). Discarded segments of the internal mammary artery and saphenous vein were used to examine (1) vascular responsiveness to NTG, sodium nitroprusside, and the calcium ionophore A23187; (2) bioconversion of NTG to 1,2- and 1,3-glyceryl dinitrate; and (3) the generation of O2–. Responses to NTG were reduced 3- to 5-fold in vessels from the nitrate group compared with control vessels (P<0.01 for both types of segments), whereas responses to sodium nitroprusside and A23187 were unchanged. Tissue content of 1,2-glyceryl dinitrate was lower (P=0.012) in the saphenous veins from the nitrate group than in those from the control group. O2– generation was greater (P<0.01) in internal mammary artery samples from the nitrate group than in those from the control group. However, incremental O2– generation induced by an inhibitor of superoxide dismutase did not affect NTG responses. Conclusions—NTG tolerance in patients with coronary artery disease is nitrate-specific and is associated with evidence of impaired NTG bioconversion. Tolerance was associated with incremental O2– generation, but short-term elevation of O2– did not affect NTG responsiveness, suggesting increased NO clearance by O2– has a minimal contribution to tolerance.Peter R. Sage, Ivan S. de la Lande, Irene Stafford, Catherine L. Bennett, George Phillipov, John Stubberfield, John D. Horowit

The Design of a Valid and Reliable Questionnaire to Measure Osteoporosis Knowledge in Women: The Osteoporosis Knowledge Assessment Tool (OKAT)

Background: Osteoporosis knowledge is an important contributor to improving exercise and calcium intake behaviour. However, there are few validated instruments for measuring osteoporosis knowledge levels. The aim of this study was to design a valid and reliable instrument to measure osteoporosis knowledge in Australian women. Methods: A 20 item instrument with true, false and don't know responses was drafted, based on the Osteoporosis Australia Osteoporosis Prevention and Self-management course and the information leaflet "Understanding Osteoporosis". The scoring range was 1 to 20. This was administered to a 467 randomly-selected, healthy women aged 25–44 years. Questionnaire performance was assessed by Flesch reading ease, index of difficulty, Ferguson's sigma, inter-item and item-total correlations, Cronbach's alpha and principal component factor analysis. Results: Flesch reading ease was higher than desirable at 45, but this was due to the use of the word osteoporosis in many items. Of the individual items 17 had an index of difficulty less than 0.75. The questionnaire had a Ferguson's sigma of 0.96, a Cronbach's alpha of 0.70 and factor analysis consistent with only one factor (osteoporosis knowledge) being measured. Levels of osteoporosis knowledge were low with a mean score of 8.8 out of 20 which suggests the OKAT may be sensitive to change. Conclusions: The OKAT for measuring osteoporosis knowledge has good psychometric properties in Australian 25–44 year old females. While it should be applicable to other Caucasian populations, this will require confirmation by further research

Randomized controlled trial of alendronate in airways disease and low bone mineral density

BACKGROUND: Patients with airways disease have been demonstrated to be at risk of osteoporosis, and this is likely to be multifactorial. Our aim was to identify patients with low bone mineral density (BMD) using a screening program, and then evaluate the benefit of daily alendronate. METHOD: Subjects with hip or lumbar spine baseline T-scores < - 2.5, or Z-score < - 1.0 commenced on alendronate/calcium (10 mg/600 mg day) or placebo/calcium, in a double blind randomized controlled trial. BMD by dual emission X-ray absorptiometry (lumbar vertebrae 2-4, neck of femur, total femur) was repeated after 12 months, with adverse events recorded. RESULTS: 145 subjects (74 male, 71 female, mean age 67, median FEV1 1.0 litres = 43% of predicted) were enrolled; 66 alendronate/calcium, 79 placebo/calcium with 24 and 26 withdrawals, respectively. Per protocol but not intention to treat analysis of covariance demonstrated statistically significant improvements in T and Z scores for lumbar spine bone mineral density (P = 0.035, P = 0.040), with no improvement demonstrated at the hip. CONCLUSIONS: Improvement in bone mineral density has been demonstrated at the lumbar spine, but not hip, by per protocol analysis, with daily alendronate, at 12 months.BJ Smith, LL Laslett, KD Pile, PJ Phillips, G Phillipov, SM Evans, AJ Esterman, and JG Berr

Randomized controlled trial of alendronate in airways disease and low bone mineral density

BACKGROUND: Patients with airways disease have been demonstrated to be at risk of osteoporosis, and this is likely to be multifactorial. Our aim was to identify patients with low bone mineral density (BMD) using a screening program, and then evaluate the benefit of daily alendronate. METHOD: Subjects with hip or lumbar spine baseline T-scores < - 2.5, or Z-score < - 1.0 commenced on alendronate/calcium (10 mg/600 mg day) or placebo/calcium, in a double blind randomized controlled trial. BMD by dual emission X-ray absorptiometry (lumbar vertebrae 2-4, neck of femur, total femur) was repeated after 12 months, with adverse events recorded. RESULTS: 145 subjects (74 male, 71 female, mean age 67, median FEV1 1.0 litres = 43% of predicted) were enrolled; 66 alendronate/calcium, 79 placebo/calcium with 24 and 26 withdrawals, respectively. Per protocol but not intention to treat analysis of covariance demonstrated statistically significant improvements in T and Z scores for lumbar spine bone mineral density (P = 0.035, P = 0.040), with no improvement demonstrated at the hip. CONCLUSIONS: Improvement in bone mineral density has been demonstrated at the lumbar spine, but not hip, by per protocol analysis, with daily alendronate, at 12 months.BJ Smith, LL Laslett, KD Pile, PJ Phillips, G Phillipov, SM Evans, AJ Esterman, and JG Berr

Gas chromatography/mass spectrometry (GC/MS) remains a pre-eminent discovery tool in clinical steroid investigations even in the era of fast liquid chromatography tandem mass spectrometry (LC/MS/MS)star, open

Liquid chromatography tandem mass spectrometry (LC/MS/MS) is replacing classical methods for steroid hormone analysis. It requires small sample volumes and has given rise to improved specificity and short analysis times. Its growth has been fueled by criticism of the validity of steroid analysis by older techniques, testosterone measurements being a prime example. While this approach is the gold-standard for measurement of individual steroids, and panels of such compounds, LC/MS/MS is of limited use in defining novel metabolomes. GC/MS, in contrast, is unsuited to rapid high-sensitivity analysis of specific compounds, but remains the most powerful discovery tool for defining steroid disorder metabolomes. Since the 1930s almost all inborn errors in steroidogenesis have been first defined through their urinary steroid excretion. In the last 30 years, this has been exclusively carried out by GC/MS and has defined conditions such as AME syndrome, glucocorticoid remediable aldosteronism (GRA) and Smith–Lemli–Opitz syndrome. Our recent foci have been on P450 oxidoreductase deficiency (ORD) and apparent cortisone reductase deficiency (ACRD). In contrast to LC/MS/MS methodology, a particular benefit of GC/MS is its non-selective nature; a scanned run will contain every steroid excreted, providing an integrated picture of an individual's metabolome. The “Achilles heel” of clinical GC/MS profiling may be data presentation. There is lack of familiarity with the multiple hormone metabolites excreted and diagnostic data are difficult for endocrinologists to comprehend. While several conditions are defined by the absolute concentration of steroid metabolites, many are readily diagnosed by ratios between steroid metabolites (precursor metabolite/product metabolite). Our work has led us to develop a simplified graphical representation of quantitative urinary steroid hormone profiles and diagnostic ratios