Low-Cost 3D-Printed Reactionware for the Determination of Fatty Acid Content in Edible Oils using a Base-Catalyzed Transesterification Method in Continuous Flow

A low-cost flow system was designed, manufactured, and tested to perform automated base-catalyzed transesterification of triacylglycerols to determine the fatty acid content in edible oils. In combination with traditional gas chromatographic analysis (GC-FID), this approach provides a semi-automated process that requires minimal manual intervention. The main flow system components, namely syringe pumps, connectors (i.e., flangeless fittings), and reactors, were manufactured using 3D-printing technology, specifically fused deposition modeling (FDM). By fine-tuning 3D-printer settings, high-quality leak-tight fittings with standard threading were manufactured in polypropylene (PP), which reduced the overall cost of the flow system significantly. Due to the enhanced reactivity in flow, lower catalyst concentrations (≤ 1.5 wt.%) were needed compared to traditional batch reactions (5 wt.%). The suitability of the automated flow method was determined by comparing results with the certified fatty acid content in sunflower seed oil from Helianthus annuus. Acceptable levels of accuracy (relative errors < 5%) and precision (RSD values ≤ 0.02%) were achieved. The mostly 3D-printed flow system was successfully used to determine the fatty acid content of sunflower and other commercial edible oils, namely avocado oil, canola oil, extra virgin olive oil, and a canola and olive oil blend. Linoleic acid (C18:2) was the major component in sunflower oil, whereas all other oils consisted mainly of oleic acid (C18:1). The fatty acid content of the edible oils was comparable to certified and literature values.

POS0637 INCIDENCE AND DETERMINANTS ASSOCIATED WITH RETRANSITIONING FROM BIOSIMILAR SB4 TO ORIGINATOR ETANERCEPT

Background:

The market entry of the etanercept biosimilar SB4 (BS-ETA) reduced prices; and, therefore, many patients in clinical practice are transitioned from originator etanercept (OR-ETA) to BS-ETA. However, previous studies demonstrated that 2.7-17.1% of patients who transitioned from OR-ETA to BS-SB4, retransitioned to OR-ETA (i.e. restarted originator), which might reduce the (financial) benefits of biosimilars. Insight in the incidence of retransitioning and characteristics of patients who are most likely to retransition, can provide lessons to clinicians for successful introduction of biosimilars.

Objectives:

To assess the incidence of retransitioning from BS-ETA to OR-ETA in patients with a rheumatic disease (RD) and to identify determinants thereof.

Methods:

All patients diagnosed with RD who transitioned in 2016 from OR-ETA to BS-ETA in a Dutch general teaching hospital (the Spaarne Gasthuis, Haarlem/Hoofddorp) were included in this cohort study. All patients were followed until retransitioning, switching to another biological, discontinuing of biological treatment death, loss to follow up or until censor date. The incidence of retransitioning and duration of BS-ETA use was assessed using the Kaplan-Meier method. Potential determinants for retransitioning, including age, gender, BS-SB4 dosing interval, use of other biologicals prior to OR-ETA, initiation or intensification of corticosteroids or immunomodulators, hospitalisations and the number of outpatient visits to the rheumatology department, were assessed in a nested case control study, using (multivariate) conditional logistic regression.

Results:

In total, 342 patients (median age 57.8 years, 53.5% females, median follow-up 2.7 years) were included. 9.4% of patients had retransitioned to OR-ETA one year after transitioning. Additionally, one year after transitioning 69.7% of patients were still treated with BS-ETA, 3.8% switched to other treatment and 17.1% discontinued all biological treatment. At the end of follow-up (median 2,7 years), 46 patients (13.5%) retransitioned to OR-ETA; median time until retransitioning was 0.50 (IQR 0.98) years.

Univariate determinants for retransitioning included female gender (OR 2.37, 95% CI 1.18-7.74), initiating or intensifying corticosteroids or immunomodulators (OR 3.24, 95% CI 1.38-7.63) and number of visits to the rheumatology department (OR 2.32, 95% CI 1.70-3.17). Based on the multivariate analysis, only the number of visits to the rheumatology department was associated with retransitioning (OR 2.19 95% CI 1.60-3.00), as demonstrated in Table 1.

Conclusion:

When introducing BS-SB4 in clinical care, clinicians should anticipate on about one in seven patients retransitioning to OR-ETA. These patients might be identified prior to retransitioning based on their contacts to the rheumatology department. Information specifically aiming for their concerns might prevent them from retransitioning. However, more qualitative studies are needed to explore patients’ underlying reasons for retransitioning, in order to improve the introduction of biosimilars in clinical care.

Table 1.Casesn = 46Controlsn = 184OR(univariate)95% CIOR(multivariate)95% CIAge, years (median, IQR)59.0 (16.5)56.5 (22.3)1.01 (0.98–1.03)-GenderMale15 (32.6%)97 (52.7%)RefRefFemale31 (67.4%)87 (47.3%)2.37 (1.18–7.74)1.36 (0.60–3.07)BS-SB4 dosing interval (index date)7 days35 (76.1%)129 (70.1%)Ref->7 days11 (23.9%)55 (29.9%)0.72 (0.33–1.56)Previous use other biologicalNo43 (93.5%)172 (93.5%)Ref-Yes3 (6.5%)12 (6.5%)1.00 (0.27–3.74)Initiation/ intensification corticosteroid/ immunomodulatorNo35 (76.1%)168 (91.3%)RefRefYes11 (23.9%)16 (8.7%)3.24 (1.38–7.63)2.31 (0.84–6.38)HospitalisationNo41 (89.1%)166 (90.2%)Ref-Yes5 (10.9%)18 (9.8%)1.12 (0.40–3.18)No. visits rheumatology departmentRef(median, IQR)2 (2)0 (1)2.32(1.70–3.17)2.19 (1.60–3.00)

Disclosure of Interests:

None declared

Exploring quantitative group-wise differentiation of Alzheimer's disease and behavioural variant frontotemporal dementia using tract-specific microstructural white matter and functional connectivity measures at multiple time points

Objectives

This study explored group-wise quantitative measures of tract-specific white matter (WM) microstructure and functional default mode network (DMN) connectivity to establish an initial indication of their clinical applicability for early-stage and follow-up differential diagnosis of Alzheimer’s disease (AD) and behavioural variant frontotemporal dementia (bvFTD).

Methods

Eleven AD and 12 bvFTD early-stage patients and 18 controls underwent diffusion tensor imaging and resting state functional magnetic resonance imaging at 3 T. All AD and 6 bvFTD patients underwent the same protocol at 1-year follow-up. Functional connectivity measures of DMN and WM tract-specific diffusivity measures were determined for all groups. Exploratory analyses were performed to compare all measures between the three groups at baseline and between patients at follow-up. Additionally, the difference between baseline and follow-up diffusivity measures in AD and bvFTD patients was compared.

Results

Functional connectivity of the DMN was not different between groups at baseline and at follow-up. Diffusion abnormalities were observed widely in bvFTD and regionally in the hippocampal cingulum in AD. The extent of the differences between bvFTD and AD was diminished at follow-up, yet abnormalities were still more pronounced in bvFTD. The rate of change was similar in bvFTD and AD.

Conclusions

This study provides a tentative indication that quantitative tract-specific microstructural WM abnormalities, but not quantitative functional connectivity of the DMN, may aid early-stage and follow-up differential diagnosis of bvFTD and AD. Specifically, pronounced microstructural changes in anterior WM tracts may characterise bvFTD, whereas microstructural abnormalities of the hippocampal cingulum may characterise AD.

Key Points

• The clinical applicability of quantitative brain imaging measures for early-stage and follow-up differential diagnosis of dementia subtypes was explored using a group-wise approach.

• Quantitative tract-specific microstructural white matter abnormalities, but not quantitative functional connectivity of the default mode network, may aid early-stage and follow-up differential diagnosis of behavioural variant frontotemporal dementia and Alzheimer’s disease.

• Pronounced microstructural white matter (WM) changes in anterior WM tracts characterise behavioural variant frontotemporal dementia, whereas microstructural WM abnormalities of the hippocampal cingulum in the absence of other WM changes characterise Alzheimer’s disease.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06061-7) contains supplementary material, which is available to authorized users.

Functional connectivity and microstructural white matter changes in phenocopy frontotemporal dementia

Objectives

Phenocopy frontotemporal dementia (phFTD) is a rare and poorly understood clinical syndrome. PhFTD shows core behavioural variant FTD (bvFTD) symptoms without associated cognitive deficits and brain abnormalities on conventional MRI and without progression. In contrast to phFTD, functional connectivity and white matter (WM) microstructural abnormalities have been observed in bvFTD. We hypothesise that phFTD belongs to the same disease spectrum as bvFTD and investigated whether functional connectivity and microstructural WM changes similar to bvFTD are present in phFTD.

Methods

Seven phFTD patients without progression or alternative psychiatric diagnosis, 12 bvFTD patients and 17 controls underwent resting state functional MRI (rs-fMRI) and diffusion tensor imaging (DTI). Default mode network (DMN) connectivity and WM measures were compared between groups.

Results

PhFTD showed subtly increased DMN connectivity and subtle microstructural changes in frontal WM tracts. BvFTD showed abnormalities in similar regions as phFTD, but had lower increased DMN connectivity and more extensive microstructural WM changes.

Conclusions

Our findings can be interpreted as neuropathological changes in phFTD and are in support of the hypothesis that phFTD and bvFTD may belong to the same disease spectrum. Advanced MRI techniques, objectively identifying brain abnormalities, would therefore be potentially suited to improve the diagnosis of phFTD.

Key points

• PhFTD shows brain abnormalities that are similar to bvFTD.

• PhFTD shows increased functional connectivity in the parietal default mode network.

• PhFTD shows microstructural white matter abnormalities in the frontal lobe.

• We hypothesise phFTD and bvFTD may belong to the same disease spectrum.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-016-4490-4) contains supplementary material, which is available to authorized users.