Immunoassay quantification of human insulin added to ternary parenteral nutrition containers: comparison of two methods

International audienceAdding insulin directly into infusion bags seems to be a useful method for controlling hyperglycemia in patients under ternary parenteral nutrition (TPN). Its efficacy is assessed by glycemic monitoring but few data are available on insulin stability in this situation. Among the various methods for quantifying insulin levels in human serum, the immunoassay ones seemed potentially appropriate for a TPN admixture containing high lipid concentrations. We sought to identify and validate which of two immunoassay methods was the better to quantify human insulin and consequently be adapted to studying its stability in a TPN admixture. Two immunoassay methods to quantify recombinant human insulin were assessed in industrial TPN: an immunoradiometric assay (IRMA) and an immunoelectrochemiluminometric assay (IECMA). Validation trials for both methods were based on the accuracy profile method. Interference with immunometric assays due to the high lipidic content of TPN was eliminated through an improved preparation protocol using a bovine serum albumin (BSA) diluted in phosphate buffer saline (PBS). The relative total error of IECMA varied from 1.74 to 4.52% while it varied from -0.32 to 8.37% with IRMA. Only IECMA provided an accuracy profile with a 95% confidence interval of calculated-tolerance limits falling between the chosen acceptance limits (i.e., total error ≤±10%). IECMA combined with a BSA dilution is a simple and semi-automatic method that provides an accurate quantification of human insulin in a TPN admixture without any interference from lipids

Local-regional recurrence of sporadic or syndromic abdominal extra-adrenal paraganglioma : incidence, characteristics, and outcome

Background: Operative excision of abdominal extra-adrenal paragangliomas (EAPs) does not preclude the late development of local-regional recurrence. We describe the incidence, characteristics, and outcome of this rarely reported feature. Methods: Retrospective analysis of local-regional recurrence that occurred during follow-up of 51 consecutive patients operated for a sporadic (n = 26) or hereditary (n = 25) EAP. Results: Seven patients with a sporadic or syndromic EAP (n = 4: von Hippel-Lindau syndrome and SDHB, SDHC, and SDHD gene mutations) underwent reoperation for a local-regional recurrence after a median time of 46 months (interquartile range [IQR], 16-100). The Kaplan-Meier estimated incidence of local-regional recurrence ( standard error of the mean) reached 1.5% +/- 7% at 5 years and 23% +/- 9% after 10 years. Recurrent EAPs were all secreting and 38% provoked clinical symptoms. New lesions were smaller than the primary EAP (P = .01) and more often associated with lymph node metastases (43% vs 4%, P = .01). Operative excision seemed complete in 5 patients. Clinical remission was maintained in 4 Patients after a median follow-up of 5 7 months (IQA 22-102). Conclusion: Local-regional recurrence of sporadic and syndromic EAPs is frequent and may be delayed beyond 10 years, requiring lifelong follow-up after the initial operation. Men technically feasible, operative excision can lead to prolonged remission