Citations

Abstract Background Factitious hypoglycemia, a deliberate attempt to induce low blood glucose levels occurring secondary to the surreptitious administration of exogenous insulin, can be difficult to diagnose due to a variety of factors including the increased use of synthetic insulin analogs in clinical practice. Traditional insulin immunoassays demonstrate variable cross-reactivity with commonly prescribed insulin analogues and their metabolites, making it difficult to measure specific analogs. The development of liquid chromatography high resolution accurate mass (LC-HRAM)-mass spectrometry (MS) assays has largely circumvented the limitations of traditional immunoassays for detection and quantitation of insulin analogs. Analytical challenges remain, however, specifically in differentiating lispro, an isomeric human insulin analog formed by the transposition of proline and lysine near the C-terminal end of the B chain, from human insulin in patient samples due to the equivalent mass-to-charge ratios of their precursor ions. Methods Immunoaffinity purification of insulin from calibrators and quality control material prepared by spiking insulin-depleted serum with pharmaceutical insulin preparations, as well as patient samples, was performed using tips coupled with anti-insulin monoclonal antibody. An automated liquid handler was programmed to perform aspiration and dispense cycles. Eluate from the purification protocol was submitted for analysis using a TLX-2 multiplex LC system paired with a Thermo Scientific Q Exactive Plus mass spectrometer. Various HPLC column chemistries were evaluated, a column passivation procedure was established, and column heater temperature was optimized to identify a combination of parameters yielding the best chromatographic separation of human insulin and lispro. Additionally, parallel reaction monitoring (PRM) targeted tandem mass spectrometry (MS/MS) analysis was utilized in combination with the full scan data to increase specificity through the monitoring of fragment ions produced from human insulin and each insulin analog. Results We found that a 1000 Å Diphenyl, 2.7 µm, 2.1 x 100 mm analytical column in a column heater maintained at a temperature of 80°C allowed for human insulin and lispro to be differentiated as two chromatographically separated extracted ion chromatographic peaks (XICs) and quantified down to 2.5 mcIU/mL with near-baseline separation. Before use, the column required passivation with a high protein buffer (0.05% bovine serum albumin in 20% acetonitrile [ACN] + 0.2% acetic acid) followed by increasingly organic buffers (20% ACN + 0.2% acetic acid and 50% ACN + 0.2% acetic acid). MS/MS was used to confirm the presence of analogs detected. Conclusions The LC-HRAM-MS method described here, coupled with optimized column chemistry, column passivation, and proper column temperature control allows for chromatographic separation of human insulin and lispro. Incorporating a PRM scan into the mass spectrometry full scan method provides confirmation of the insulin detected in the XICs. The results obtained from preliminary studies suggest this method is appropriate for use to facilitate the clinical investigation of suspected factitious hypoglycemia with the ability to differentiate isomeric compounds, such as human insulin and lispro.

Abstract Background Our established method for measuring plasma catecholamines utilized a Shimadzu HPLC coupled to an ESA Coulochem III electrochemical detector. Chromatographic run times were long, resulting in slow turnaround times. Instrument maintenance was labor intensive, and the assay was prone to interferences. To overcome these limitations, we changed the method to liquid chromatography-tandem mass spectrometry (LC-MS/MS) measurements. Methods After the addition of a labeled internal standard for each analyte, samples are loaded onto 50 mg of activated alumina at pH 8.6, utilizing a Tris-HCl, sodium carbonate and EDTA buffer. After incubation the alumina is then washed with 50% acetonitrile followed by water. Elution off the alumina is performed with 2% acetic acid. Derivatization is then performed on the eluate utilizing acetaldehyde and a cyanoborohydride buffer. Following derivatization, the samples are analyzed for epinephrine, norepinephrine, and dopamine by LC-MS/MS using a Sciex 7500 coupled to a ThermoFisher Scientific TLX-4 equipped with Vanquish pumps. Chromatographic separation was obtained using a Phenomenex Kinetex 2.6 um BiPhenyl 50x3 mm analytical column. Results Runtimes were significantly shorter than with the previous method, and no interferences were observed. Assay validation consisted of: intra/inter assay precision, accuracy, recovery, linearity, carryover, limit of detection (LOD), and interferences. Three levels were assessed for intra assay precision and each of the analytes monitored yielded %CVs of less than 6%. Four levels were assessed for inter assay precision and each of the analytes monitored yielded %CVs of less than 10%. When using linear regression analysis to compare results with the previous clinical assay, the slope, y-intercept and R2 were the following; dopamine: 1.06, 2.74, 0.978; epinephrine: 0.905, 2.20, 0.989; norepinephrine: 0.919, 9.75, 0.953. Spike and recovery from five samples yielded a mean average recovery of 93.4% for dopamine, 100% for epinephrine and 98.1% for norepinephrine. For linearity 4 samples were diluted and the mean % difference from expected was -1.66% for dopamine, -0.25% for epinephrine and 1.78% for norepinephrine. Blanks were injected following the high standard and carryover was negligible. LOD was determined by running a low sample pool along with a blank over 20 assays. The LOD was determined to be less than the LLOQ. Sixty-two common drugs/vitamins along with varying levels of hemolysis, lipemia, and bilirubin were also tested to ensure no interferences were seen. Conclusions The LC-MS/MS method exceeded the performance of the historical Shimdazu HPLC system with ESA Coluochem III electrochemical detector method. We anticipate that the better analytical performance will improve the testing quality of our patients.

Abstract Background Patients with sporadic or hereditary Medullary Thyroid Carcinoma (MTC) often undergo total thyroidectomy and lymph node dissection, with postoperative surveillance relying on serum calcitonin levels and ultrasound examinations. According to American Thyroid Association (ATA) guidelines, detectable levels of serum calcitonin and Carcinoembryonic Antigen (CEA) post-thyroidectomy suggest potential disease persistence or recurrence, necessitating frequent monitoring for early detection. This study sought to reassess the role of postoperative calcitonin levels in identifying possible tumor recurrence. Methods A retrospective analysis was conducted using Siemens Atellica to test calcitonin levels in 562 samples collected between 09/27/2022 and 08/11/2023, at least 3 months post-total thyroidectomy. Imaging studies performed within 6 months of the calcitonin assessment were also reviewed. Sample pools with calcitonin concentrations near 3.00 and 5.00 pg/mL were utilized to determine the limit of quantification (LoQ). CEA results were included for comparison. Additionally, 16 serum samples were analyzed using the Roche Cobas system at a reference laboratory. Results Precision analysis around 3.00 and 5.00 pg/mL revealed coefficients of variation (CVs) of 16.49% and 8.87%, respectively. Comparison of calcitonin levels between Siemens Atellica and Roche Cobas systems demonstrated consistent levels < 5.00 pg/mL in 15 out of 16 samples, indicating alignment and reliability between the platforms. A calcitonin cutoff of 1.89 pg/mL yielded 43% sensitivity and 67% specificity, while a cutoff of 5.00 pg/mL resulted in 0% sensitivity and 100% specificity. Conclusions Our findings suggest that a 5 pg/mL calcitonin cutoff on the Siemens Atellica platform may be suitable for identifying tumor persistence or recurrence in post-thyroidectomy patients within our institution. However, individual laboratories should establish their LoQ criteria when interpreting calcitonin levels for postoperative monitoring of tumor recurrence.

Stenosis of the left main coronary artery (LM stenosis) is associated with significant mortality and morbidity due to the large area of affected myocardium. Evidence on the use of percutaneous coronary intervention (PCI) for the treatment of LM stenosis is growing. However, the role of Western guidelines on patients in the Asian-Pacific region is unclear due to anatomical variations, substantial heterogeneity in healthcare resources and infrastructure, and the lack of consensus on the optimal management of LM stenosis in the Asia-Pacific region. Hence, an Asian Pacific Society of Cardiology (APSC) working group developed consensus recommendations on the use of PCI in the management of LM stenosis in the Asia-Pacific region. The APSC expert panel reviewed and appraised the available evidence using the Grading of Recommendations Assessment, Development, and Evaluation system. Consensus recommendations were developed and put to an online vote. Consensus was reached when 80% of votes for a given recommendation were in support of ‘agree’ or ‘neutral’. The resulting 12 statements provide guidance for clinical practitioners in the region on the use of PCI in the treatment of patients with LM stenosis.

Telemedicine for stroke (Telestroke) has been a key component to efficient, widespread acute stroke care for many years. The expansion of reimbursement through the Furthering Access to Stroke Telemedicine Act and rapid deployment of telemedicine resources during the COVID-19 public health emergency have further expanded remote care, with practitioners of varying educational backgrounds, and experience providing acute stroke care via telemedicine (Telestroke). Some Telestroke practitioners have not had fellowship-level vascular neurology training and many are without training specific to virtual modalities. While many vascular neurology fellowship programs incorporate Telestroke training into the curriculum, components of this curriculum are not consistent, extent of involvement is variable, and not all fellows receive hands-on training in remote care. Furthermore, the extent of training and evaluation of Telestroke in American Board of Psychiatry and Neurology training requirements and Accreditation Council for Graduate Medical Education assessments for vascular neurology fellowship are not standardized. We suggest that Telestroke be formally incorporated into vascular neurology fellowship curricula and provide considerations for key components of this training and metrics for evaluation.

Pheochromocytomas are rare neuroendocrine tumors characterised by the secretion of catecholamines and their metabolites. While some patients may be asymptomatic, they can also present with various symptoms including hypertensive crisis, headaches, palpitations, diaphoresis or other signs of catecholamine toxicity. Adrenal haemorrhage, though rare, is a potentially fatal complication that is often diagnosed during autopsy. In all patients with suspected pheochromocytoma, regardless of whether haemorrhagic conversion has occurred, prompt diagnosis is imperative. Early identification allows for the timely initiation of treatment, preventing potentially life-threatening complications. This case report details the haemorrhagic conversion of an undiagnosed pheochromocytoma in a female patient in her 30s.

Abstract Background Celiac disease (CeD) is a chronic autoimmune disorder triggered by the ingestion of gluten in persons with the genetic risk factors human leukocyte antigens (HLA)-DQ2 and DQ8. Diagnostic evaluation of patients with suspected CeD often includes serology tests for tissue transglutaminase (tTG) antibodies. While the presence of HLA-DQ2 or DQ8 is required for the initiation and development of CeD, the genetic risk associated with the various alleles is not equivalent. Previous studies in patients with normal total IgA demonstrated the risk gradients of various HLA-DQ2 and DQ8 heterodimers in CeD. However, the impact of both gene variants in IgA deficient patients has not been investigated. In this study, HLA-DQ2 and HLA-DQ8 as risk factors for tTG-IgG positivity in IgA deficient patients were evaluated. Methods Retrospective data was collected from a cohort of individuals (n=3,515) with IgA concentrations below the age-dependent reference interval with suspicion for CeD who were tested for HLA-DQ genotyping and tTG-IgG (reference interval < 6 U/mL) at Mayo Clinic Laboratories. Total IgA was measured using quantitative nephelometry (Siemens BN™ II System); HLA typing was performed using the reverse SSO DNA typing assay (LABType SSO kits). tTG-IgG was determined by enzyme-linked immunosorbent assay (QUANTA Lite R h-tTG, Werfen Diagnostics) on the Dynex Agility System. The prevalence and frequency distribution of HLA-DQ2 and DQ8 haplotypes were determined and the odds ratio (OR) was calculated to evaluate the risk gradient for tTG-IgG positivity based on different HLA-DQ variants. Results Among IgA deficient patients, 58% (n=2,041) expressed HLA-DQ2 or DQ8 haplotypes. Relative to patients without permissive alleles, patients homozygous for HLA-DQ2.5 exhibited a significantly increased risk for tTG-IgG positivity (OR = 10.98, 95% CI: 6.56-18.18, p < 0.001) while those homozygous for HLA-DQ2.2 and DQ8 did not (DQ2.2/DQ2.2_OR = 0.72, 95% CI: 0.04-3.44, p = 0.75; DQ8/DQ8_OR = 0.96, 95% CI: 0.05-4.64, p = 0.97). Patients heterozygous for HLA-DQ2.5 (DQ2.5/x) displayed a lower odds ratio relative to homozygous patients (OR = 3.31, 95% CI: 2.29-4.82, p < 0.001); however, the risk for tTG-IgG positivity increased in the presence of HLA-DQ2.2 (DQ2.5/DQ2.2_OR = 7.59, 95% CI: 4.48-12.65, p < 0.001) or HLA-DQ8 (DQ2.5/DQ8_OR = 6.26, 95% CI: 3.55-10.73, p < 0.001) alleles. Conversely, in the absence of HLA-DQ2.5, HLA-DQ2.2 heterozygotes (DQ2.2/x_OR = 2.80, 95% CI: 1.77-4.39, p < 0.001) and HLA-DQ8 heterozygotes (DQ8/x_OR = 0.99, 95% CI: 0.52-1.77, p = 0.99) displayed lower correlations with tTG-IgG positivity, suggesting a potential risk elevation for tTG-IgG positivity is associated with the combination of DQ2.5 and DQ2.2 or DQ8. Conclusions Our study indicates the risk gradient of HLA-DQ genes in IgA deficient patients. Overall, compared to patients without HLA-DQ2 or DQ8 haplotypes, the homozygous HLA-DQ2.5 genotype had the highest correlation with tTG-IgG positivity, followed by HLA-DQ2.5/DQ2.2 and HLA-DQ2.5/DQ8 heterodimers. The results suggest that HLA-DQ2.2 or HLA-DQ8 alone does not confer risk, but when in the presence of HLA-DQ2.5 these alleles may increase the risk for tTG-IgG positivity. Results from this study shed light on the risk of CeD in patients with IgA deficiency.

Abstract INTRODUCTION Brain tumors constitute significant morbidity and mortality in sub-Saharan Africa (SSA). Improvements in neuro-oncology practice and research have seen increased diagnosis of brain tumors. However, to our knowledge, there have been no previous projects on brain tumor genetics in SSA. To understand the feasibility of developing brain tumor biobanking and registries, this project aims to start by mapping out the current neuro-oncology capacity in terms of workforce and available services. METHODOLOGY We will conduct a descriptive questionnaire-based online survey among a cross section of neuro-oncology practitioners spread across SSA countries. The dissemination of the survey questionnaire will be facilitated by the Society for Neuro-oncology in SSA (SNOSSA). The Google designed questionnaire will capture information on the distribution, and number of available neuro-oncology care practitioners, capacity for brain tumor diagnosis and management, cancer registration, tumor biobanking, and research. CLINICAL IMPACT AND CONCLUSION This study will generate robust data from SSA, which can be used to improve future research and promote advocacy towards brain tumor diagnosis and management. This work will also serve as a pilot study for subsequent research that will focus on the development of brain tumor-specific registries and biorepositories in SSA.

Background The pipeline embolization device (PED) has been increasingly used to treat brain aneurysms; however, concerns have been raised about braid stability with newer drawn filled tubing technology devices. Objective To evaluate braid stability of PED early generations using data from the PREMIER trial. Methods All consecutive intracranial aneurysms treated with PED (Classic and Flex) within the PREMIER trial were reviewed for braid stability (fish mouthing, foreshortening, braid bump, braid collapsing). Immediate postprocedure cone-beam CT and angiography were compared with 1- and 2- years' follow-up. Analyses included safety, measured with the modified Rankin Scale (mRS) score, including +1 mRS point and a good clinical outcome (mRS score 0–2), vessel stenosis ≥50%, effectiveness measured with Raymond-Roy Scale, and re-treatment rates. Results 133/141 aneurysms had a complete dataset. 8/133 (6%) aneurysms showed braid deformations. Inter-reader agreement was excellent (κ=0.83). Braid deformations were statistically significantly associated with in-stent vessel stenosis >50% (P=0.029), without impact on effectiveness or safety. Fish mouthing was found in 1/133 (0.75%) at 1 year, causing >50% vessel stenosis. Foreshortening occurred in 6/133 (4.5%), and braid bump in 1/133 (0.75%) associated with severe in-stent stenosis. Four other cases (3.0%) of asymptomatic in-stent stenosis due to neointimal hyperplasia were seen without braid changes. No new braid stability deformations were found at the 2-year follow-up. Conclusion Our study demonstrates excellent braid stability among patients treated with the PED Classic and Flex in the PREMIER trial. Within the uncommon braid changes observed, none affected the PED safety or efficacy. Trial registration number NCT02186561 .