Screening for primary aldosteronism using the newly developed IDS-iSYS® automated assay system

BACKGROUND

The recommended approach to screening for primary aldosteronism (PA) in at-risk populations is to determine the ratio of aldosterone concentration (serum (SAC)/plasma (PAC)) to renin measured in plasma as activity (PRA) or concentration (DRC). However, lack of assay standardisation mandates the need for method-specific decision thresholds and clinical validation in the local population.

AIM

The study objective was to establish method-specific aldosterone: renin ratio (ARR) cut-offs for PA in men and women using the IDS-iSYS® assay system (IDS plc).

METHODS

A prospective cohort study design was used. PAC and DRC were measured immunochemically in ethylenediamine-tetraacetic acid (EDTA) plasma on the IDS-iSYS® instrument.

RESULTS

A total of 437 subjects (218 men, 219 women) were recruited including: healthy normotensive volunteers (n=266) and women taking the oral contraceptive pill (OCP; n=15); patients with essential hypertension (EH; n=128); confirmed PA (n=16); adrenal cortical carcinoma (ACC; n=3); Addison's disease (AD; n=4) and phaeochromocytoma/paraganglioma (PPGL; n=5). In this population, an ARR cut-off at >37.4 pmol/mIU provided 100% diagnostic sensitivity, 96% specificity and positive likelihood ratio for PA of 23:1. When the ARR decision threshold was stratified according to gender, a cut-off of >26.1 pmol/mIU in men and >113.6 pmol/mIU in women resulted in diagnostic sensitivity and specificity of 100%.

CONCLUSION

This study demonstrates that decision thresholds for PA should not only be method-specific but also gender-specific. However, given the small number of PA patients (n=16), particularly women (n=4), further validation through a prospective study with a larger PA cohort is required before the thresholds presented here could be recommended for routine clinical use.

Runx1 Orchestrates Sphingolipid Metabolism and Glucocorticoid Resistance in Lymphomagenesis

The three‐membered RUNX gene family includes RUNX1, a major mutational target in human leukemias, and displays hallmarks of both tumor suppressors and oncogenes. In mouse models, the Runx genes appear to act as conditional oncogenes, as ectopic expression is growth suppressive in normal cells but drives lymphoma development potently when combined with over‐expressed Myc or loss of p53. Clues to underlying mechanisms emerged previously from murine fibroblasts where ectopic expression of any of the Runx genes promotes survival through direct and indirect regulation of key enzymes in sphingolipid metabolism associated with a shift in the “sphingolipid rheostat” from ceramide to sphingosine‐1‐phosphate (S1P). Testing of this relationship in lymphoma cells was therefore a high priority. We find that ectopic expression of Runx1 in lymphoma cells consistently perturbs the sphingolipid rheostat, whereas an essential physiological role for Runx1 is revealed by reduced S1P levels in normal spleen after partial Cre‐mediated excision. Furthermore, we show that ectopic Runx1 expression confers increased resistance of lymphoma cells to glucocorticoid‐mediated apoptosis, and elucidate the mechanism of cross‐talk between glucocorticoid and sphingolipid metabolism through Sgpp1. Dexamethasone potently induces expression of Sgpp1 in T‐lymphoma cells and drives cell death which is reduced by partial knockdown of Sgpp1 with shRNA or direct transcriptional repression of Sgpp1 by ectopic Runx1. Together these data show that Runx1 plays a role in regulating the sphingolipid rheostat in normal development and that perturbation of this cell fate regulator contributes to Runx‐driven lymphomagenesis. J. Cell. Biochem. 118: 1432–1441, 2017. © 2016 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

Screening for phaeochromocytoma and paraganglioma: impact of using supine reference intervals for plasma metanephrines with samples collected from fasted/seated patients

Background The Endocrine Society Clinical Practice Guideline on Phaeochomocytoma and Paraganglioma recommends phlebotomy for plasma-free metanephrines with patients fasted and supine using appropriately defined reference intervals. Studies have shown higher diagnostic sensitivities using these criteria. Further, with seated-sampling protocols, for result interpretation, reference intervals that do not compromise diagnostic sensitivity should be employed. Objective To determine the impact on diagnostic performance and financial cost of using supine reference intervals for result interpretation with our current plasma-free metanephrines fasted/seated-sampling protocol. Methods We conducted a retrospective cohort study of patients who underwent screening for PPGL using plasma-free metanephrines from 2009 to 2014 at Galway University Hospitals. Plasma-free metanephrines were measured using liquid chromatography-tandem mass spectrometry. Supine thresholds for plasma normetanephrine and metanephrine set at 610 pmol/L and 310 pmol/L, respectively, were used. Results A total of 183 patients were evaluated. Mean age of participants was 53.4 (±16.3) years. Five of 183 (2.7%) patients had histologically confirmed PPGL (males, n=4). Using seated reference intervals for plasma-free metanephrines, diagnostic sensitivity and specificity were 100% and 98.9%, respectively, with two false-positive cases. Application of reference intervals established in subjects supine and fasted to this cohort gave diagnostic sensitivity of 100% with specificity of 74.7%. Financial analysis of each pretesting strategy demonstrated cost-equivalence (€147.27/patient). Conclusion Our cost analysis, together with the evidence that fasted/supine-sampling for plasma-free metanephrines, offers more reliable exclusion of PPGL mandates changing our current practice. This study highlights the important advantages of standardized diagnostic protocols for plasma-free metanephrines to ensure the highest diagnostic accuracy for investigation of PPGL.

International scale implementation of the CNOSSOS-EU road traffic noise prediction model for epidemiological studies

The EU-FP7-funded BioSHaRE project is using individual-level data pooled from several national cohort studies in Europe to investigate the relationship of road traffic noise and health. The detailed input data (land cover and traffic characteristics) required for noise exposure modelling are not always available over whole countries while data that are comparable in spatial resolution between different countries is needed for harmonised exposure assessment. Here, we assess the feasibility using the CNOSSOS-EU road traffic noise prediction model with coarser input data in terms of model performance. Starting with a model using the highest resolution datasets, we progressively introduced lower resolution data over five further model runs and compared noise level estimates to measurements. We conclude that a low resolution noise model should provide adequate performance for exposure ranking (Spearman's rank = 0.75; p < 0.001), but with relatively large errors in predicted noise levels (RMSE = 4.46 dB(A)).

Pure aldosterone-secreting adrenocortical carcinoma in a patient with refractory primary hyperaldosteronism

We describe a young male patient with longstanding hypertension, who was diagnosed with primary hyperaldosteronism and treated by an attempted retroperitoneoscopic total unilateral adrenalectomy for a left-sided presumed aldosterone-secreting adenoma. Imaging had shown an unremarkable focal adrenal lesion with normal contralateral adrenal morphology, and histology of the resected specimen showed no adverse features. Post-operatively, his blood pressure and serum aldosterone levels fell to the normal range, but 9 months later, his hypertension recurred, primary aldosteronism was again confirmed and he was referred to our centre. Repeat imaging demonstrated an irregular left-sided adrenal lesion with normal contralateral gland appearances. Adrenal venous sampling was performed, which supported unilateral (left-sided) aldosterone hypersecretion. Redo surgery via a laparoscopically assisted transperitoneal approach was performed and multiple nodules were noted extending into the retroperitoneum. It was thought unlikely that complete resection had been achieved. His blood pressure returned to normal post-operatively, although hypokalaemia persisted. Histological examination, from this second operation, showed features of an adrenocortical carcinoma (ACC; including increased mitoses and invasion of fat) that was assessed as malignant using the scoring systems of Weiss and Aubert. Biochemical hyperaldosteronism persisted post-operatively, and detailed urine steroid profiling showed no evidence of adrenal steroid precursors or other mineralocorticoid production. He received flank radiotherapy to the left adrenal bed and continues to receive adjunctive mitotane therapy for a diagnosis of a pure aldosterone-secreting ACC.

A review of the management of positive biochemical screening for phaeochromocytoma and paraganglioma: a salutary tale

BACKGROUND

Phaeochromocytomas (PC) and paragangliomas (PGL) are rare neuroendocrine tumours of chromaffin cells. Diagnosis depends on biochemical evidence of excessive production of catecholamines. This is straightforward when test results are orders of magnitude above the concentrations expected in healthy individuals and those with essential hypertension. Equivocal results pose a management dilemma.

AIM

We reviewed biochemical screens that were positive and the ensuing management for PC/PGL at our institution. The objective was to inform the development of a standardised approach to investigation and clinical follow-up.

METHOD

All records of positive biochemical screening for PC/PGL were extracted from the laboratory information system between January 2004 and June 2012. Clinical notes of patients with positive results were reviewed.

RESULTS

A total of 2749 biochemical screens were performed during the evaluation period. Of these, 106 (3.9%) performed on 82 patients were positive. Chart review determined that 12/82 patients had histologically confirmed PC/PG. Of the 70 patients remaining, the most common indication for biochemical screening was hypertension and the medical subspecialty most frequently requesting the test was Endocrinology. The primary team carried out repeat testing on 35/70 (50%) patients and in 29 results normalised. Notably, 35/70 (50%) patients did not have any follow-up of positive test results.

CONCLUSION

This study highlights the necessity for a standardised diagnostic protocol for PC/PGL. We suggest that appropriate follow-up of borderline-elevated results should first include repeat biochemical testing. This should be performed under standardised pre-analytical conditions and where possible off all potentially interfering medications, measuring plasma free metadrenalines.

Young adult type 1 diabetes care in the West of Ireland: an audit of hospital practice

BACKGROUND

It is well recognised that management of young adults with type 1 diabetes (T1DM) poses difficult challenges for physicians and health care organisations as a whole. In Ireland and in particular the west of Ireland there has been little audit or research on young adults with T1DM and the services available to them.

DESIGN

In 2011 a retrospective review of this patient population in our territory referral centre was carried out.

RESULTS

The average glycaemic control in this population was poor at 81mmols/mol and diabetes related complications were present in 32%. Engagement by this population with services was poor with an average of 3 missed clinic appointments over a 24 month period.

CONCLUSION

These results have prompted a re think of how health care professionals can deliver a service that better suits the needs of this challenging patient group.

A double-blind randomized controlled trial showing the analgesic and anesthetic properties of lidocaine E to be equivalent to those of ropivicaine and bupivacaine in carpal tunnel release surgery

In a three-phase trial, the anesthetic properties of lidocaine, bupivacaine and ropivicaine were compared in carpal tunnel release surgery. In phase I, two groups of 25 sequential patients were injected with either lidocaine plain 2% or lidocaine 2% with adrenaline 1:100,000 (E), as the local anesthetic for outpatient carpal tunnel release surgery. Subjective injection pain, postoperative pain at 2 h increments and the number of analgesic pills taken were recorded. During the first postoperative hours, outcome measures were superior in the lidocaine E group. In phase II, a double-blind randomized design compared 42 patients injected with either lidocaine E or a combination of lidocaine E and bupivacaine. Postoperative pain scores and analgesic pills taken were compared using nonparametric statistical tests. During the first 4 h there was a slight benefit in the duration of the anesthetic and fewer pain pills were used in the bupivacaine group. Phase III was a randomized double-blind comparison of ropivicaine and lidocaine E 2% in 72 patients. There was a slight decrease in pain scores and fewer analgesic pills required during the first 6 h in the ropivicaine group. Lidocaine plain 2% provided significantly inferior analgesic and anesthetic properties compared with lidocaine E 2%, bupivacaine or ropivicaine. Sequential randomized comparisons between lidocaine E and bupivacaine and ropivicaine showed clinical equivalence. The present study showed lidocaine E 2% to be a satisfactory and comparatively cost-effective anesthetic for outpatient carpal tunnel surgery.

Measurement of atmospheric neutrino oscillations with IceCube

We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored.

First observation of PeV-energy neutrinos with IceCube

We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04±0.16 and 1.14±0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current ν(e,μ,τ) (ν(e,μ,τ)) or charged-current ν(e) (ν(e)) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082±0.004(stat)(-0.057)(+0.041)(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9×10(-3) (2.8σ) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.

An unusual presentation of MEN2A

A 35-year-old woman presented with non-specific symptoms of fatigue and weight loss. Radiological investigations diagnosed a metastatic process and large bilateral adrenal masses. Histology from a liver biopsy and skin biopsy confirmed a diagnosis of metastatic medullary thyroid cancer. Further biochemical investigations revealed a positive 24-h urinary metanephrine collection and evidence of primary hyperparathyroidism. Genetic testing confirmed a mutant RET oncogene, confirming our clinical suspicion of multiple endocrine neoplasia type 2 (MEN2A) syndrome. The patient had no family history of endocrine disease and presented with widespread metastatic disease, making this an unusual presentation of MEN2A syndrome. Furthermore cutaneous metastases are rarely encountered in conjunction with metastatic medullary thyroid cancer. This case draws attention to the importance of genetic counselling in first-degree relatives of patients with confirmed MEN2A. This allows for timely diagnosis and reduced morbidity and mortality.

The prevalence of diabetes, pre-diabetes and the metabolic syndrome in an Irish regional homeless population

BACKGROUND

Diabetes is a major chronic health condition. Prevalence is rising, superseding public health estimates. Chronic diseases are more common among lower socioeconomic groups, for example, the homeless population. There is paucity of data on the health status of the homeless population in Ireland, and the prevalence of diabetes and associated cardiovascular risk factors is unknown.

AIM

We aimed to assess the prevalence of diabetes, pre-diabetes and the metabolic syndrome (MetS) in an Irish regional homeless population.

DESIGN

This study is a cross-sectional study of the homeless population living in a regional university city of Ireland.

METHODS

After informed consent and following an overnight fast, blood was drawn for fasting plasma glucose, total cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein and glycosylated haemoglobin (HbA1c). A 75 g glucose load was given orally and an oral glucose tolerance test completed. Anthropometric measurements and blood pressure were recorded. Smoking, alcohol and drug status were noted.

RESULTS

Of the 252 participants, 8% (n = 20), 10% (n = 24) and 21% (n = 54) were diagnosed with type 2 diabetes, pre-diabetes and MetS, respectively. Obesity (body mass index >30) was present in 22%, while 90% displayed abdominal obesity. Participants who screened positive for diabetes, pre-diabetes and MetS demonstrated an inferior cardiovascular risk profile.

CONCLUSION

The prevalence of diabetes, pre-diabetes and MetS in this homeless population is in keeping with national estimates. As this cohort is less likely to seek health care, this may result in later diagnosis and a greater risk of diabetic complications at presentation.

Measurement of the atmospheric νe flux in IceCube

We report the first measurement of the atmospheric electron neutrino flux in the energy range between approximately 80 GeV and 6 TeV, using data recorded during the first year of operation of IceCube's DeepCore low-energy extension. Techniques to identify neutrinos interacting within the DeepCore volume and veto muons originating outside the detector are demonstrated. A sample of 1029 events is observed in 281 days of data, of which 496±66(stat)±88(syst) are estimated to be cascade events, including both electron neutrino and neutral current events. The rest of the sample includes residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is consistent with models of atmospheric neutrinos in this energy range. This constitutes the first observation of electron neutrinos and neutral current interactions in a very large volume neutrino telescope optimized for the TeV energy range.

Search for dark matter annihilations in the sun with the 79-string IceCube detector

We have performed a search for muon neutrinos from dark matter annihilation in the center of the Sun with the 79-string configuration of the IceCube neutrino telescope. For the first time, the DeepCore subarray is included in the analysis, lowering the energy threshold and extending the search to the austral summer. The 317 days of data collected between June 2010 and May 2011 are consistent with the expected background from atmospheric muons and neutrinos. Upper limits are set on the dark matter annihilation rate, with conversions to limits on spin-dependent and spin-independent scattering cross sections of weakly interacting massive particles (WIMPs) on protons, for WIMP masses in the range 20-5000  GeV/c2. These are the most stringent spin-dependent WIMP-proton cross section limits to date above 35  GeV/c2 for most WIMP models.