Connector sensors for permittivity-based thrombus monitoring in extracorporeal life support

Extracorporeal circulation is vital in cardiovascular surgery, but thrombus formation at connector interface is a major threat. Optical coherence tomography (OCT) is presently used to monitor thrombogenesis at connectors, but it is expensive to install and complex to use. This study fabricated and evaluated a connector sensor for real-time permittivity-based thrombus monitoring at tube-connector interface. Computational simulations were initially done to pre-evaluate the applicability of connector sensor. The sensor was fabricated by incorporating two stainless steel electrodes on acrylic tube for measuring permittivity changes at the tube-connector interface. OCT images were also taken from the interface at intervals for comparisons. Results show that the sensor was able to detect thrombus formation at the interface in form of sudden rise in permittivity after time t = 9 min. The permittivity changes were confirmed by OCT images which showed thrombus formation after time t = 14 min implying that permittivity changes were due to regional aggregation of red blood cells. The connector sensor is therefore envisioned as an affordable alternative to OCT for real-time permittivity-based monitoring of thrombogenesis at tube-connector interface.

Investigation of Physiological Swelling on Conductivity Distribution in Lower Leg Subcutaneous Tissue by Electrical Impedance Tomography

There is a strong need for a non-invasive measurement technique that is capable of accurately identifying the physiological condition change or heterogeneity of subcutaneous adipose tissue (SAT) by localizing the abnormalities within the compartment. This paper aims to investigate the feasibility of Electrical Impedance Tomography (EIT) to assess the interstitial fluid in subcutaneous adipose tissue as an enhancement method of bioelectrical impedance spectroscopy (BIS). Here, we demonstrate the preliminary result of EIT with a wearable 16 electrodes sensor. The image-based reference EIT with fat weighted threshold method is proposed. In order to evaluate the performance of our novel method, a physiological swelling experiment is conducted, and Multi-Frequency Bioelectrical Impedance Analysis (MFBIA) is also applied as a comparison with EIT results. The experimental results showed that the proposed method was able to distinguish the physiological swelling condition and effectively to remove the unexpected background noise. Furthermore, the conductivity variation in the subcutaneous layer had a good correlation with extracellular water volume change from MFBIA data; the correlation coefficient R² = 0.927. It is concluded that the proposed method provides a significant prospect for SAT assessment.

2206Prevalence and determinants of complicated grief in bereaved caregivers of patients admitted for cardiovascular diseases

Introduction

Few studies have examined complicated grief in bereaved caregivers of patients with cardiovascular diseases (CVD), in contrast with studies in caregivers of patients with cancers. We examined the prevalence and determinants of complicated grief among bereaved caregivers of patients with CVD.

Methods

We conducted a cross-sectional survey using a self-administered questionnaire for bereaved family members of CVD patients who had died in the cardiology departments of 9 tertiary care centers in Japan. We assessed bereaved caregiver grief status using the Brief Grief Questionnaire (BGQ), and its association with their depression (Patient Health Questionnaire-9 [PHQ-9]). Questionnaire also covered following associated factors: bereaved family member and patient characteristics, end-of-life care (Care Evaluation Scale [CES], a scale for assessment of the structure and process of care); and the quality of the deceased patients' death (Good Death Inventory [GDI]).

Results

A total of 269 bereaved caregivers (mean age, 64±12 years; 35% male) of patients with CVD (heart failure n=155 myocardial infarction n=32, cardiopulmonary arrest n=15, arrhythmia n=8, and others n=59) were enrolled in the study. Overall, 14.1% of the bereaved caregivers had complicated grief (BGQ≥8), 32.3% had subthreshold complicated grief (BGQ=5–7), and 13.3% had depression (PHQ-9≥10). Bereaved caregivers with complicated grief frequently developed depression (58% vs. 6%, p<0.001). Among the bereaved caregivers with complicated grief, the assessment of end-of-life care was worse (CES score: 28 [21–40] vs. 23 [19–39], p=0.04), and the assessment of the deceased patients' quality of death tended to be worse (GDI score: 4.0 [3.0–4.8] vs. 4.3 [3.7–4.9], p=0.05). The cause of admission as well as preferences of the patient and family (e.g., treatment [focusing on extending life vs. relieving discomfort], desire for information, place of end-of-life) were not associated with the prevalence of complicated grief. The prevalence of complicated grief was associated with loss of a spouse, poor psychological health during the deceased patients' admission, and poor preparation for the patient's imminent death (all p<0.05). Bereaved caregivers with complicated grief had experienced more decisional burdens regarding the deceased patients' treatment (55% vs. 25%, p=0.001). Notably, 64% of bereaved caregivers with complicated grief were not treated (i.e., neither routine follow-up by psychiatrists/psychotherapist nor prescription for anti-depressants/tranquilizers).

Conclusions

The prevalence of complicated grief of bereavement was 14.0%. When subthreshold complicated grief was included, the prevalence of complicated grief increased to include half of the caregivers; therefore, routine screening of the bereaved could be recommended. Clinicians should pay particular attention to bereaved families with high risk factors to identify those at risk for future development of complicated grief.

P684Long-term outcomes in patients with cancer undergoing percutaneous coronary intervention: analysis from a Japan multicenter registry

Background

Cancer and cardiovascular disease (CVD) is the most common cause of death in developed countries, and substantial overlap exist in their medical care. However, the detailed and updated information on outcome of cancer patients with cardiovascular disease (CVD), particularly in clinically significant coronary artery disease (CAD) remain unknown.

Purpose

We sought to describe the prevalence and long-term outcomes of cancer patients undergoing percutaneous coronary intervention (PCI), which has become a coronerstone in the management of CVD.

Methods

Patient data extracted from a regional prospectiveprocedure-based multicenter registry for PCI was analyzed. A total of 4,455 patients who underwent PCI at 15 hospitals within metropolitan Tokyo from September 2008 to 2012 were followed for 2 years. “Active” cancer patient was defined as having a history of cancer not cured or in remission. We analyzed in acute and stable presentation.The occurrence of clinical outcomes was assessed via Kaplan-Meier survival curve, and Cox-regression hazard model to adjust for known clinical predictors.

Results

Within the studied patients, 173 (3.9%) had a concomitant “active” cancer at the time of intervention. There was a significant difference between the patients with and without active cancer in each situation. In stable presentation, cancer group were older, lower BMI, frequently had silent ischemia, COPD and cerebrovascular/peripheral disease, and less often had dyslipidemia compared with non-cancer group. In acute presentation, cancer group were older, frequently had COPD, CKD, peripheral disease and history of HF compared with non-cancer group. The prescription rate of RAAS inhibitor was lower in the cancer group than in the non-cancer group in acute presentation. Notably, in both acute and stable presentation, these patients had significantly higher risk of all-cause mortality (HR 8.01: 95%, p<0.001 and HR5.53: 95%, p<0.001, respectively), and they were also at higher risk of major cardo- and cerebrovascular events (MACCE; HR2.38, p<0.001, HR2.33, p=0.001), when referenced to non-cancer patients after 2 year of follow-up.

Conclusion

Cancer patient was present in 3.9% of all PCI patients and was strongly associated with both non-cardiac and cardiac adverse events.

P2622Use of intravenous vasodilators in patients hospitalized with acute heart failure: insights from Tokyo cardiovascular care unit network database

Background

Despite recommendations from clinical practice guidelines, there is scant evidence confirming the effects of vasodilators on clinical outcomes in patients with acute heart failure (AHF).

Purpose

We sought to investigate the effects of intravenous vasodilators on clinical outcomes and to identify the potential patient populations that would benefit from its use.

Methods

Data of 26 212 consecutive patients urgently hospitalized for AHF between 2009 and 2015 were extracted from a multicenter data registration system (Tokyo Cardiovascular Care Unit Network Database, including 72 institutions within the Tokyo metropolitan area in Japan). Patients who did not present with typical AHF episodes, including those without pulmonary congestion on physical and/or chest X-ray and serum B-type natriuretic peptide level <500 pg/ml, as well as those who had hypotension and/or hypoperfusion (systolic blood pressure [SBP] <100 mmHg) as dominant presentation, were excluded. Propensity scores were calculated with multiple imputation and 1:1 matching performed between patients with and without vasodilators. The primary endpoint was in-hospital mortality and the secondary endpoints were length of intensive/cardiovascular care unit (ICU/CCU) stay and hospital stay.

Results

Overall, 8 863 patients were included in the present analysis; they were predominantly male (57%) with a median age of 79 (interquartile range: 70–86) years. Compared with the group without vasodilator use, the vasodilator group had higher SBPs and heart rates and higher frequency of assisted ventilation use, but lower frequency of intravenous diuretics use. After propensity score matching, there were no significant differences in in-hospital mortality rates (7.8% vs. 8.9% in patients without vasodilators, p=0.16) or in length of ICU/CCU stay (5.8 days vs. 5.4 days, p=0.44) and hospital stay (22.7 days vs. 23.8 days, p=0.22) between the groups. However, in subgroup analyses, favorable impacts of vasodilator use on in-hospital mortality were observed among patients who had higher SBPs and among those who had no atrial fibrillation upon admission (Figure). In addition, vasodilators were likely to be more effective in AHF patients with SBP increasing; while levels below 140 mmHg of SBP appeared to be associated with an increased risk for mortality among patients treated with vasodilators compared with those without vasodilators.

Figure 1

Conclusions

In patients with AHF, vasodilator use was not universally associated with improved in-hospital outcomes; however, its effect was dependent of individual clinical presentation. Detailed phenotyping might aid tailoring of treatment strategies for patients with AHF.

Acknowledgement/Funding

the Tokyo Metropolitan Government

Numerical Study of Enhancement of Positive Dielectrophoresis Particle Trapping in Electrode-Multilayered Microfluidic Device

Enhancement of positive dielectrophoresis (pDEP) particle trapping by a co-occurring fluid flow under an ac electric field in an electrode-multilayered microfluidic device is investigated by three-dimensional particle-fluid flow simulations. The particle motion near one cross section of the microfluidic device is simulated under a zero flow condition by the Eulerian-Lagrangian method incorporating the ac electrothermal effect, thermal buoyancy, and dielectrophoresis. The mean trapping rate under the steady state R_m is evaluated from the simulated number of trapped particles N_trap for 54 cases with four parameters: electrode excitation pattern, medium conductivity σ, applied voltage ϕ_e, and the real part of the Clausius-Mossotti factor Re[K(ω)]. The simulated pDEP velocity in the upper part of the flow channel is validated by an experiment using cell suspension and is fitted so that the non-dimensional velocity error is within 15% of a typical velocity of pDEP. The mean trapping rate R_m is greatly increased by the fluid flow only in the high conductivity and high voltage cases. Regardless of the electrode excitation pattern, R_m increased almost proportionally to the inflow rate into the capture region, where the pDEP force is effective. From a fitted equation of the results, the increase of R_m when Re[K(ω)] = 0.1 to 0.5 is found to be about 20% to 30% of the number of particles transported into the capture regions. The results quantify the enhancement of pDEP trapping by the fluid flow occurring under practical conditions in the device.

Effects of Sitagliptin on Pancreatic Beta-Cells in Type 2 Diabetes With Sulfonylurea Treatment: A Prospective Randomized Study

Background

This prospective randomized, multicenter, open-label, comparative study was performed to analyze the effects of sitagliptin on glycemic control and maintenance of beta-cell function in patients with poorly controlled type 2 diabetes treated with low-dose glimepiride.

Methods

Forty-one patients with type 2 diabetes mellitus treated with low-dose glimepiride (≤ 2 mg/day) were prospectively enrolled in this study (age: 20 - 75 years; hemoglobin A1c (HbA1c): 7.4- 9.4%). The patients were randomized into two groups: the glimepiride (G) group, in which glimepiride dose was increased gradually to 6 mg/day, and the sitagliptin (S) group, in which sitagliptin was added at a dose of 50 mg/day.

Results

HbA1c level was significantly decreased after 24 weeks, but not 12 weeks, in the G group, while a significant decrease was seen after 12 weeks in the S group. Although there were no significant differences in HbA1c level at 24 weeks between the two groups (P = 0.057). The overall trend of changes in HbA1c level suggested that the glucose-lowering effects were superior in the S group. Furthermore, a significant change in fasting glucose was seen in the S group, but not in the G group. Glycemic control target was achieved in 36.7% and 16.7% patients in the S group and the G group, respectively. The proinsulin/insulin (P/I) ratio was significantly increased in the G group, whereas it tended to decrease in the S group. After 24 weeks of treatment, no significant difference was observed in the P/I ratio between the two groups, whereas a significant difference was noted in the ΔP/I (amount of change). Albuminuria tended to increase in the G group compared with the S group.

Conclusion

The results of the present study suggested that sitagliptin effectively lowered hyperglycemia and that it may have a protective effect on pancreatic beta-cells when combined with a low dose of glimepiride. Therefore, sitagliptin may represent a useful combination therapy with low-dose sulfonylurea, not only for achieving glycemic control but also for protection of pancreatic beta-cells.

Microfluidic device embedding electrodes for dielectrophoretic manipulation of cells-A review

Microfluidic device embedding electrodes realizes cell manipulation with the help of dielectrophoresis. Cell manipulation is an important technology for cell sorting and cell population purification. Till now, the theory of dielectrophoresis has been greatly developed. Microfluidic devices with various arrangements of electrodes have been reported from the beginning of the single non-uniform electric field to the later multiple physical fields. This paper reviews the research status of microfluidic device embedding electrodes for cell manipulation based on dielectrophoresis. Firstly, the working principle of dielectrophoresis is explained. Next, cell manipulation approaches based on dielectrophoresis are introduced. Then, different types of electrode arrangements in the microfluidic device for cell manipulation are discussed, including planar, multilayered and microarray dot electrodes. Finally, the future development trend of the dielectrophoresis with the help of microfluidic devices is prospected. With the rapid development of microfluidic technology, in the near future, high precision, high throughput, high efficiency, multifunctional, portable, economical and practical microfluidic dielectrophoresis will be widely used in the fields of biology, medicine, agriculture and so on.

Image Reconstruction Under Contact Impedance Effect in Micro Electrical Impedance Tomography Sensors

Contact impedance has an important effect on micro electrical impedance tomography (EIT) sensors compared to conventional macro sensors. In the present work, a complex contact impedance effect ratio ξ is defined to quantitatively evaluate the effect of the contact impedance on the accuracy of the reconstructed images by micro EIT. Quality of the reconstructed image under various ξ is estimated by the phantom simulation to find the optimum algorithm. The generalized vector sampled pattern matching (GVSPM) method reveals the best image quality and the best tolerance to ξ. Moreover, the images of yeast cells sedimentary distribution in a multilayered microchannel are reconstructed by the GVSPM method under various mean magnitudes of contact impedance effect ratio |ξ|. The result shows that the best image quality that has the smallest voltage error U_E = 0.581 is achieved with measurement frequency f = 1 MHz and mean magnitude |ξ| = 26. In addition, the reconstructed images of cells distribution become improper while f < 10 kHz and mean value of |ξ| > 2400.

Distinct Motion of GFP-Tagged Histone Expressing Cells Under AC Electrokinetics in Electrode-Multilayered Microfluidic Device

The distinct motion of GFP-tagged histone expressing cells (Histone-GFP type cells) has been investigated under ac electrokinetics in an electrode-multilayered microfluidic device as compared with Wild type cells and GFP type cells in terms of different intracellular components. The Histone-GFP type cells were modified by the transfection of green fluorescent protein-fused histone from the human lung fibroblast cell line. The velocity of the Histone-GFP type cells obtained by particle tracking velocimetry technique is faster than Wild type cells by 24.9% and GFP type cells by 57.1%. This phenomenon is caused by the more amount of proteins in the intracellular of single Histone-GFP type cell than that of the Wild type and GFP type cells. The more amount of proteins in the Histone-GFP type cells corresponds to a lower electric permittivity ϵ_c of the cells, which generates a lower dielectrophoretic force exerting on the cells. The velocity of Histone-GFP type cells is well agreed with Eulerian-Lagrangian two-phase flow simulation by 4.2% mean error, which proves that the fluid motion driven by thermal buoyancy and electrothermal force dominates the direction of cells motion, while the distinct motion of Histone-GFP type cells is caused by dielectrophoretic force. The fluid motion does not generate a distinct drag motion for Histone-GFP type cells because the Histone-GFP type cells have the same size to the Wild type and GFP type cells. These results clarified the mechanism of cells motion in terms of intracellular components, which helps to improve the cell manipulation efficiency with electrokinetics.

Indomethacin inhibits melanogenesis via down-regulation of Mitf mRNA transcription

Non-steroidal anti-inflammatory drugs (NSAIDs) exhibit several divergent biological effects. In this study, we investigated the effect of indomethacin on melanin synthesis using B16F1 melanoma cells. Indomethacin inhibited α-melanocyte stimulating hormone (α-MSH)-enhanced melanin synthesis in a dose-dependent manner. Western blotting analysis revealed that indomethacin significantly suppressed tyrosinase and Mitf protein levels. In a luciferase reporter assay, we found that indomethacin reduced tyrosinase promoter activity. Moreover, real-time RT-PCR analysis showed that indomethacin lowered mRNA levels of melanogenic genes, including Mitf. Together, our findings indicate that indomethacin inhibits melanogenesis via the suppression of Mitf transcription.

Development of three-dimensional integrated microchannel-electrode system to understand the particles' movement with electrokinetics

An optical transparent 3-D Integrated Microchannel-Electrode System (3-DIMES) has been developed to understand the particles' movement with electrokinetics in the microchannel. In this system, 40 multilayered electrodes are embedded at the 2 opposite sides along the 5 square cross-sections of the microchannel by using Micro Electro-Mechanical Systems technology in order to achieve the optical transparency at the other 2 opposite sides. The concept of the 3-DIMES is that the particles are driven by electrokinetic forces which are dielectrophoretic force, thermal buoyancy, electrothermal force, and electroosmotic force in a three-dimensional scope by selecting the excitation multilayered electrodes. As a first step to understand the particles' movement driven by electrokinetic forces in high conductive fluid (phosphate buffer saline (PBS)) with the 3-DIMES, the velocities of particles' movement with one pair of the electrodes are measured three dimensionally by Particle Image Velocimetry technique in PBS; meanwhile, low conductive fluid (deionized water) is used as a reference. Then, the particles' movement driven by the electrokinetic forces is discussed theoretically to estimate dominant forces exerting on the particles. Finally, from the theoretical estimation, the particles' movement mainly results from the dominant forces which are thermal buoyancy and electrothermal force, while the velocity vortex formed at the 2 edges of the electrodes is because of the electroosmotic force. The conclusions suggest that the 3-DIMES with PBS as high conductive fluid helps to understand the three-dimensional advantageous flow structures for cell manipulation in biomedical applications.

Investigation of particle inertial migration in high particle concentration suspension flow by multi-electrodes sensing and Eulerian-Lagrangian simulation in a square microchannel

The inertial migration of neutrally buoyant spherical particles in high particle concentration (αpi  > 3%) suspension flow in a square microchannel was investigated by means of the multi-electrodes sensing method which broke through the limitation of conventional optical measurement techniques in the high particle concentration suspensions due to interference from the large particle numbers. Based on the measured particle concentrations near the wall and at the corner of the square microchannel, particle cross-sectional migration ratios are calculated to quantitatively estimate the migration degree. As a result, particle migration to four stable equilibrium positions near the centre of each face of the square microchannel is found only in the cases of low initial particle concentration up to 5.0 v/v%, while the migration phenomenon becomes partial as the initial particle concentration achieves 10.0 v/v% and disappears in the cases of the initial particle concentration αpi  ≥ 15%. In order to clarify the influential mechanism of particle-particle interaction on particle migration, an Eulerian-Lagrangian numerical model was proposed by employing the Lennard-Jones potential as the inter-particle potential, while the inertial lift coefficient is calculated by a pre-processed semi-analytical simulation. Moreover, based on the experimental and simulation results, a dimensionless number named migration index was proposed to evaluate the influence of the initial particle concentration on the particle migration phenomenon. The migration index less than 0.1 is found to denote obvious particle inertial migration, while a larger migration index denotes the absence of it. This index is helpful for estimation of the maximum initial particle concentration for the design of inertial microfluidic devices.