Competitive Immunoassay in a Microfluidic Biochip for In-Field Detection of Abscisic Acid in Grapes

Viticulture and associated products are an important part of the economy in many countries. However, biotic and abiotic stresses impact negatively the production of grapes and wine. Climate change is in many aspects increasing both these stresses. Routine sample retrievals and analysis tend to be time-consuming and require expensive equipment and skilled personnel to operate. These challenges could be overcome through the development of a miniaturized analytic device for early detection of grapevine stresses in the field. Abscisic acid is involved in several plant processes, including the onset of fruit ripening and tolerance mechanisms against drought stress. This hormone can be detected through a competitive immunoassay and is found in plants in concentrations up to 10-1 mg/mL. A microfluidic platform is developed in this work which can detect a minimum of 10-11 mg/mL of abscisic acid in buffer. Grape samples were tested using the microfluidic system alongside benchmark techniques such as high-performance liquid chromatography. The microfluidic system could detect the increase to 10-5 mg/mL of abscisic acid present in real berry samples at the veraison stage of ripening.

Microfluidic bioreactors for enzymatic synthesis in packed-bed reactors-Multi-step reactions and upscaling

Enzymatic synthesis of biochemical commodities is of upmost importance as it represents a greener alternative to traditional chemical synthesis and provides easier downstream processing strategies compared to fermentation-based processes. A microfluidic system used to optimize the enzymatic production of both levodopa (L-DOPA) and dopamine in both single-step and multistep-reaction sequences with yield of approximately 30 % for L-DOPA production and 70 % for dopamine production is presented. The system for L-DOPA production was then up-scaled (780-fold increase) to a milliliter scale system by maintaining similar mass transport properties resulting in the same yield, space-time yield and biocatalyst yield as its microscale counterpart. The results obtained for yield and biocatalyst yield (351.7 mg_L-DOPA mg^-1_Tyr h^-1) were similar to what is reported in the literature for similar systems, however the space-time yield (0.806 mg_L-DOPA L^-1 h^-1) was smaller. This work demonstrates a microfluidic bioreactor that can be used for complex optimizations that can be performed rapidly while reducing the consumption of reagents by immobilizing the catalyst on a carrier which can then be used in a packed-bed reactor, thus extending the enzyme life span.

P1541 Left ventricular global longitudinal strain can predict the risk of ventricular arrhythmias in hypertrophic cardiomyopathy patients with preserved left ventricle function

Introduction

Hypertrophic cardiomyopathy (HCM) is characterized by a heterogeneous clinical expression with increased risk of sudden cardiac death (SCD) from ventricular arrhythmias (VAs).Several studies have shown that patients with malignant arrhythmias have increased electrical dispersion and in homogeneity of intraventricular conduction. Strain by echocardiography is an excellent tool for assessing regional and global left ventricular (LV) function and mechanical dispersion reflects heterogeneous myocardial contraction. We aimed to explore the value of strain parameters in prediction of VAs in HCM with LV preserved systolic function.

Methods

Retrospective observational study including all patients with HCM and ICD implanted in setting of primary prevention in our centre. Patients with LVEF < 40% or coronary artery disease were excluded. LV GLS was defined as the average of peak longitudinal strains from a 16 LV segments model, obtained from three apical views. Time to peak strain was defined as the time from onset Q/R wave on ECG to peak negative longitudinal strain during the entire cardiac cycle. Mechanical dispersion was defined as the standard deviation of time to peak negative strain in 16 LV segments. Patients with VA (group1) and patients without VA (group2) were compared.

Results

The study population included 48 patients, 63.3% of male gender. A family history of HCM was present in 64 pts (43%). All patients were under anti arrhythmic therapy (BB in 95.6%, other anti-arrhythmic in 28.2%). VAs (sustained and non sustained) were documented in 27 (55%) patients. The study groups did not differ regarding to mean age (54 ± 12 vs 56 ± 12 years, p = 0.67), male gender (54% vs 56%, p = 0.87) and BB therapy (91% vs 96%,p = 0.07). Mean LVEF was 58% in group 1 and 61% in group 1, p = 0.56; a LVOT gradient >30mmHg was present in 52% of group 1 pts and 45% of group 2 pts, p = 0.06. Mean wall thickness was 22mm vs 18 mm, p = 0.03, respectively.

GLS was significantly lower in group 1 (- 13.9 ±3.4 vs -16.1 ±3.5, p = 0.02), mechanic dispersion was significantly higher in group 1(81 ± 14 vs 60 ± 12ms, respectively, p = 0.01. Using a multivariate logistic regression model including variables included in SCD HCM risk score proposed by ESC mechanical dispersion (OR: 1.54 (1.03–8.7), p = 0,03) was a strong and independent risk predictor of VA. Using optimal cut-off values from ROC analyses, patients with mechanical dispersion >67 ms (AUC = 0.82, p= 0.02) had more VAs.

Conclusions

Mechanical dispersion and GLS may help to identify HCM patients with high risk of VAs and SCD.

Abstract P1541 Figure 1

P3358Cardiovascular risk, aortic valve microcalcification and vascular microcalcification: is there a link?

18F-sodium fluoride (18F-NaF) has been used to evaluate aortic stenosis. It is know that its uptake is related with microcalcification. The purpose of this study is to assess the relationship between 18F-NaF uptake by the aortic valve and by the main arterial vessels and cardiovascular risk.

Twenty-five hypertensive patients without known cardiovascular disease or aortic stenosis underwent PET-CT with 18F-NaF. Cardiovascular risk was assessed through the ASCVD risk calculator. The patients had a mean age of 64.0±8.6 years and 56% were males. The mean ASCVD risk was of 28.8±19.0 (IQR: 10–48.5). The uptake of 18F-NaF assessed through the corrected uptake per lesion (CUL = max SUV – mean blood-pool SUV) was of 0.49±0.14 (IQR: 0.44–0.57) and the mean uptake in the aortic, coronary and carotid territories was of 0.66±0.21 (IQR: 0.53 - 0.76).The patients were classified according to the ASCVD: Group A: patients with a risk above the 50thpercentile of the ASCVD risk distribution (50thpercentile=25), 12 patients) and Group B: patients with a risk under or equal to the 50thpercentile of the ASCVD risk distribution, 13 patients.

The uptake of 18F-NaF in the aortic valve (AoV)and in the main vascular territories (VT) were evaluated in both groups: A vs B: AoV CUL = 0.57±0.09 vs 0. 42±0.14, p=0.005; VT= 0.78±0.16 vs 0.54±0.20, p=0.003. We also evaluate the relation between AoV uptake and VT uptake and they were significantly related (r=0.69, p=0.0001).

In conclusion on this study microcalcification of the aortic valve and in the main vessels, evaluated through 18F-NaF uptake, were related between them and with cardiovascular risk reinforcing the importance of cardiovascular risk prevention in aortic valve degeneration and vascular atherosclerosis.

P2655ST-elevation myocardial infarction in women: a more satisfactory outcome?

Background

Despite all the advances registered in the last decade regarding acute myocardial infarction with ST-segment elevation (STEMI) treatment, this entity remains prevalent and highly lethal. Women constitute a lower proportion of STEMI patients, however, they show important differences when compared to men. Thanks to the lower representation of women in STEMI trials, less is know about this patient subpopulation.

Purpose

To determine and understand gender differences in patients admitted with STEMI in a coronary care unit (CCU).

Methods

Observational retrospective study of patients admitted with STEMI in a CCU, between 2006 and 2017. Patients were split between groups according to gender and were assessed in terms of risk factors, diagnosis, treatment, complications and mortality.

Results

A total of 2516 patients were included in the study. 1833 were men (72.9%) and 682 were women (27.1%). Mean age was superior in women (73.3±13.2 vs. 64.1±12.8 years, p<0.001), and displayed a greater cardiovascular comorbidity burden such as hypertension (79.6% vs. 66.2%, p<0.001) and diabetes (55.8% vs. 45.3%, p<0.001). At admission time women registered a higher mean TIMI (2.79 vs. 2.62, p=0.009) and GRACE score (166.3 vs. 146.3, p<0.001) which did not reflect in a higher hospital stay (mean 4.75 vs. 5.29 days, p=0.043). Before admission women were less treated with aspirin (26.4% vs. 33.2%, p=0.014) and statins (36.8% vs. 46.5%, p=0.001). There were no differences regarding access to revascularization (98% vs. 96.5%, p=0.105) but women presented more normal coronary angiographies (10.2% vs. 3.6%, p<0.001). During hospital stay, women evolved more to Killip-Kimball (KK) class III (4.5% vs. 1.9%, p<0.001) and KK class IV (15.9% vs. 11.2%, p<0.001). Intra-hospital (13.9% vs. 8.2%, p<0.001), 1-month (18.4% vs. 13.2%, p<0.001), 6-month (22.2% vs. 16.1%, p<0.001) and 1-year mortality (25.7% vs. 17.8%, p<0.01) was superior in women. After multivariate analysis heart failure on admission (OR 9.2, CI 95% 6.7–12.8), intravenous amiodarone use (OR 3.5, CI 95% 2.5–4.8), diabetes (OR 2.3, CI 95% 1.8–2.8), female gender (OR 1.6, CI 95% 1.3–2.0) and peak serum creatinine during hospital stay (OR 1.7, CI 95% 1.6–1.9) were independent predictors of 1-year mortality. After adjustment for age, diabetes, hypertension, previous acute myocardial infarction and initial KK, female gender maintained its potency as a significant 1-year mortality predictor.

Conclusions

Women presenting with STEMI register poorer outcomes compared to men. In our study, female gender was considered a good independent predictor of short-term and long-term mortality.

Bi-axially Oriented Blown Film Technology

A set of commercial polyethylenes (three LDPE and three LLDPE) was rheological characterized and processed in a laboratory double bubble extrusion line with the purpose of investigating: i) whether their relative processability could be predicted in the laboratory and ii) the effect of operating and machine variables on processability. Oscillatory shear and extensional measurements were able to differentiate the various materials, who also behaved quite differently upon processing. Those with a stronger shear thinning behaviour, higher elasticity and higher melt strength were the most suited to the process. Bubble stability and thickness uniformity were assumed as the main requirements for processability. The former was estimated by monitoring the time required to stabilize the bubble and examining any variation/oscillation in size/shape. Bubble stability depends on the interaction between various parameters, the most relevant being those related with the film cooling stage, namely the axial position of the air rings, the air flow rate and air velocity. The study was preceded by an assessment of the performance of the re-heating oven and die/calibration/centring, as these parameters could also narrow the practical operating window.

Drosophila BRUCE inhibits apoptosis through non-lysine ubiquitination of the IAP-antagonist REAPER

Active caspases execute apoptosis to eliminate superfluous or harmful cells in animals. In Drosophila, living cells prevent uncontrolled caspase activation through an inhibitor of apoptosis protein (IAP) family member, dIAP1, and apoptosis is preceded by the expression of IAP-antagonists, such as Reaper, Hid and Grim. Strong genetic modifiers of this pathway include another IAP family gene encoding an E2 ubiquitin conjugating enzyme domain, dBruce. Although the genetic effects of dBruce mutants are well documented, molecular targets of its encoded protein have remained elusive. Here, we report that dBruce targets Reaper for ubiquitination through an unconventional mechanism. Specifically, we show that dBruce physically interacts with Reaper, dependent upon Reaper's IAP-binding (IBM) and GH3 motifs. Consistently, Reaper levels were elevated in a dBruce -/- background. Unexpectedly, we found that dBruce also affects the levels of a mutant form of Reaper without any internal lysine residues, which normally serve as conventional ubiquitin acceptor sites. Furthermore, we were able to biochemically detect ubiquitin conjugation on lysine-deficient Reaper proteins, and knockdown of dBruce significantly reduced the extent of this ubiquitination. Our results indicate that dBruce inhibits apoptosis by promoting IAP-antagonist ubiquitination on unconventional acceptor sites.

Influence of substrate conductivity on circulation reversal in evaporating drops

Nonuniform evaporation from sessile droplets induces radial convection within the drop, which produces the well-known "coffee-ring" effect. The evaporation also induces a gradient in temperature and consequently a gradient in surface tension, generating a Marangoni flow. Here we investigate theoretically and experimentally the thermal Marangoni flow and establish criteria to gauge its influence. An asymptotic analysis indicates that the direction of the flow depends on the relative thermal conductivities of the substrate and liquid, k_{R} identical withk_{S}/k_{L}, reversing direction at a critical contact angle over the range 1.45<k_{R}<2. We corroborate the theory experimentally and demonstrate that the Marangoni flow can significantly influence the resulting patterns of particle deposition.

Early retardation of 99mTc-DTPA radioaerosol transalveolar clearance in irradiated canine lung

The alteration of 99mTc-labeled diethylenetriaminepentaacetic acid (DTPA) transalveolar clearance in an initial phase of radiation lung injury was experimentally investigated.

METHODS

Fourteen dogs were irradiated to the hemithorax with a single dose of 20 Gy. A DTPA radioaerosol study was performed before irradiation and on day 12 after irradiation. On day 14, the DTPA study was repeated again, with seven animals undergoing the study after inhalation of an aerosolized synthetic surfactant. The penetration index (P.I.) and clearance half-time (T(1/2)) of DTPA were measured in each lung. To evaluate the changes in lung surfactant after irradiation, alveolar lipids were stained in the resected lungs (n = 14), and the amounts of alveolar surfactant phospholipid and protein were measured by a bronchoalveolar lavage study in another six irradiated dogs.

RESULTS

In all of the 14 irradiated animals, DTPA radioaerosol distributed uniformly throughout the lungs without significant changes in P.I. The T(1/2) values in irradiated lungs were significantly prolonged compared with the matched baseline values and those in nonirradiated lungs (P < 0.05 and 0.001, respectively). The aerosolized synthetic surfactant retarded the DTPA clearance both in the irradiated and in the nonirradiated lungs (P < 0.001) without significant changes in P.I. The histologic and bronchoalveolar lavage studies revealed an increase of alveolar surfactant materials in the irradiated lungs without substantial histologic changes in the alveolar structures.

CONCLUSION

DTPA transalveolar clearance was retarded soon after irradiation. Increased alveolar surfactant may be partly responsible for this retarded DTPA clearance because the aerosolized synthetic surfactant also prolonged the clearance in nonirradiated lungs. A DTPA clearance test is sensitive for the early detection of radiation lung injury and seems helpful for clarifying the association of epithelial integrity changes and lung surfactant in radiation lung injury.

Structure of Tetrahymena CCT theta gene and its expression under colchicine treatment

We report here the cloning and the characterization of the Tetrahymena pyriformis chaperonin-containing-TCP1 theta gene (TpCCT theta), an orthologue of the mouse chaperonin gene CCT theta. TpCCT theta gene is interrupted by eight introns, ranging in size between 91 and 419 nucleotides, and encodes a protein consisting of 540 amino acid residues (59.1 kDa), with a putative pI of 5.73. The amino acid sequence of TpCCT theta reveals 39.4-46.0% identity with the sequences of Candida albicans and mouse CCT theta subunits and 28.0-32.6% identity with the other TpCCT subunits known so far. We have studied the expression of this gene in exponentially growing Tetrahymena cells and in cells treated with colchicine for different times. The steady-state levels of CCT theta mRNA rapidly decrease in the first 30 min of colchicine treatment. Interestingly, treatment for subsequent 60 min gives expression levels higher than those found in exponentially growing cells.

Effect of inhaled surfactant on pulmonary deposition and clearance of technetium-99m-DTPA radioaerosol

To establish the effect of an aerosolized synthetic surfactant (Exosurf) on pulmonary 99mTc-diethylenetriamine pentaacetic acid (DTPA) aerosol deposition and clearance, radioaerosol studies were performed at varying times and under varying conditions after surfactant inhalation in canine lungs.

METHODS

Twenty-three dogs had a baseline 99mTc-DTPA study; 2 days later the study was repeated after inhalation of a 1.5-ml/kg dose of Exosurf aerosolized by an ultrasonic nebulizer. The clearance half-time (T1/2) of 99mTc-DTPA from each lung was measured at different times (from 10 min to 3 hr) after Exosurf inhalation. For comparison, five animals had a 99mTc-DTPA study 10 min after inhalation of the same dose of saline as Exosurf. An additional five animals inhaled a 99mTc-DTPA-Exosurf mixture to investigate the distribution of Exosurf.

RESULTS

Technetium-99m-DTPA distributed uniformly without significant changes in penetration indexes before and after inhalation of Exosurf and the 99mTc-DTPA-Exosurf mixture. After Exosurf inhalation, 99mTc-DTPA clearance at 10 min (T1/2; 35.6 +/- 8.7 min; n = 6) and 40 min (29.4 +/- 6.3 min; n = 4) was significantly prolonged compared with the matched baseline values (24.7 +/- 6.4 min, p < 0.0001; and 21.7 +/- 8.9 min, p = 0.01, respectively). However, later clearance times were not prolonged. By contrast, after saline inhalation, 99mTc-DTPA distributed inhomogeneously, and clearance times T1/2) were not altered from the matched baseline values.

CONCLUSION

Aerosolized Exosurf distributes homogeneously in the lungs. Exosurf initially retards 99mTc-DTPA aerosol clearance, but 99mTc-DTPA transalveolar clearance returns to baseline rates within 1-2 hr. Technetium-99m-DTPA aerosol clearance measurements can be used to monitor the effect of inhaled Exosurf on pulmonary epithelial integrity.