resources (MC Lab, South San Francisco, CA, USA). The steroid conversion was analyzed following our laboratory procedure and characterized by liquid chromatography equipped with mass spectrometry (LC–MS) (5) . Cell culture, transfection, western
Jasmeet Kaur, Luis Casas and Himangshu S Bose
Punith Kempegowda, Lauren Quinn, Lisa Shepherd, Samina Kauser, Briony Johnson, Alex Lawson and Andrew Bates
high performance liquid chromatography with a diode-array detector (HPLC-DAD), gas chromatography–mass spectrometry (GC-MS) and high-resolution mass spectrometry (LC-QT of MS). Samples were compared to a library of compounds present on each instrument
Angelo Paci, Ségolène Hescot, Atmane Seck, Christel Jublanc, Lionel Mercier, Delphine Vezzosi, Delphine Drui, Marcus Quinkler, Martin Fassnacht, Eric Bruckert, Marc Lombès, Sophie Leboulleux, Sophie Broutin and Eric Baudin
Mitotane (o,p′-DDD) is the standard treatment for advanced adrenocortical carcinoma (ACC). Monitoring of plasma mitotane levels is recommended to look for a therapeutic window between 14 and 20mg/L, but its positive predictive value requires optimization. We report the case of an ACC patient with a history of dyslipidemia treated with mitotane in whom several plasma mitotane levels >30mg/L were found together with an excellent neurological tolerance. This observation led us to compare theoretical or measured o,p′-DDD and o,p′-DDE levels in a series of normolipidemic and dyslipidemic plasma samples to explore potential analytical issues responsible for an overestimation of plasma mitotane levels. We demonstrate an overestimation of mitotane measurements in dyslipidemic patients. Mitotane and o,p′-DDE measurements showed a mean 20% overestimation in hypercholesterolemic and hypertriglyceridemic plasma, compared with normolipidemic plasma. The internal standard p,p′-DDE measurements showed a parallel decrease in hypercholesterolemic and hypertriglyceridemic plasma, suggesting a matrix effect. Finally, diluting plasma samples and/or using phospholipid removal cartridges allowed correcting such interference.
- Hypercholesterolemia (HCH) and hypertriglyceridemia (HTG) induce an overestimation of plasma mitotane measurements.
- We propose a routine monitoring of lipidemic status.
- We propose optimized methodology of measurement before interpreting high plasma mitotane levels.
Charlotte Boughton, David Taylor, Lea Ghataore, Norman Taylor and Benjamin C Whitelaw
We describe severe hypokalaemia and hypertension due to a mineralocorticoid effect in a patient with myelodysplastic syndrome taking posaconazole as antifungal prophylaxis. Two distinct mechanisms due to posaconazole are identified: inhibition of 11β hydroxylase leading to the accumulation of the mineralocorticoid hormone 11-deoxycorticosterone (DOC) and secondly, inhibition of 11β hydroxysteroid dehydrogenase type 2 (11βHSD2), as demonstrated by an elevated serum cortisol-to-cortisone ratio. The effects were ameliorated by spironolactone. We also suggest that posaconazole may cause cortisol insufficiency. Patients taking posaconazole should therefore be monitored for hypokalaemia, hypertension and symptoms of hypocortisolaemia, at the onset of treatment and on a monthly basis. Treatment with mineralocorticoid antagonists (spironolactone or eplerenone), supplementation of glucocorticoids (e.g. hydrocortisone) or dose reduction or cessation of posaconazole should all be considered as management strategies.
- Combined hypertension and hypokalaemia are suggestive of mineralocorticoid excess; further investigation is appropriate.
- If serum aldosterone is suppressed, then further investigation to assess for an alternative mineralocorticoid is appropriate, potentially using urine steroid profiling and/or serum steroid panelling.
- Posaconazole can cause both hypokalaemia and hypertension, and we propose that this is due to two mechanisms – both 11β hydroxylase inhibition and 11β HSD2 inhibition.
- Posaconazole treatment may lead to cortisol insufficiency, which may require treatment; however, in this clinical case, the effect was mild.
- First-line treatment of this presentation would likely be use of a mineralocorticoid antagonist.
- Patients taking posaconazole should be monitored for hypertension and hypokalaemia on initiation and monthly thereafter.
N F Lenders and J R Greenfield
suppression test. Computed tomography (CT) adrenals demonstrated a 3.2 cm left adrenal tumour with density measurements of 39 HU pre-contrast and washout of 65% ( Fig. 1 ). 24-h urine steroid metabolites (gas chromatography-mass spectrometry) are demonstrated
Kamel Mohammedi, Charbel Abi Khalil, Sophie Olivier, Imane Benabad, Ronan Roussel and Michel Marre
based on the findings of hypoinsulinemic hypoglycemia associated with the presence of big IGF2 (4) . Data about the detection methods of big IGF2 are scarce. Size-exclusion acid chromatography has been considered as the gold standard method for the
Khaled Aljenaee, Osamah Hakami, Colin Davenport, Gemma Farrell, Tommy Kyaw Tun, Agnieszka Pazderska, Niamh Phelan, Marie-Louise Healy, Seamus Sreenan and John H McDermott
allows for separation by structural difference ( 2 ). Thus, methods of HbA1c analysis can be divided into two categories: those based on the charge differences (such as in cation-exchange chromatography, electrophoresis, and isoelectric focusing) and
Benjamin G Challis, Nicolai J Wewer Albrechtsen, Vishakha Bansiya, Keith Burling, Peter Barker, Bolette Hartmann, Fiona Gribble, Stephen O'Rahilly, Jens J Holst and Helen L Simpson
.e. proglucagon X-61), and the second, a sandwich ELISA assay that only detects intact glucagon (proglucagon 33–61). To further characterise these glucagon moieties, plasma was subjected to gel filtration chromatography. Analysis of the gel filtration profile
Cheuk-Lik Wong, Chun-Kit Fok and Vicki Ho-Kee Tam
/mL 251** <149 MN pg/mL 56** <58 Abnormal results are in bold. *Performed in Hospital A using liquid chromatography-tandem mass spectrometry (LC–MS/MS) – reference ranges: NE < 627 nmol/24 h, EPI < 86 nmol/24 h
Pinaki Dutta, Anuradha Aggarwal, Yashpal Gogate, Uma Nahar, Viral N Shah, Mandeep Singla, N Khandelwal and Anil Bhansali
IGF2’ or immature IGF2, which is a 10–17 kDa fraction and mature IGF2 which is a 7.5 kDa form. These variants of IGF2 can only be detected by BIOGEL P-60 column chromatography. ‘Big IGF2’ normally contributes only 10–20% to the total pool of IGF2, but